chapter 20

20

Connect Highlights

patella alta patella baja genu valgum genu varum genu recurvatum

hemarthrosis translation iliotibial band friction

syndrome

Key Terms

Anatomy of the Knee 557

Functional Anatomy 562

Assessing the Knee Joint 563

Prevention of Knee Injuries 577

Recognition and Management of Specifi c Injuries 578

Knee Joint Rehabilitation 595

Summary 600

Outline

ObjectivesWhen you fi nish this chapter you should be able to

Recognize the normal structural and functional knee anatomy.

Demonstrate the various ligamentous and meniscal stability tests discussed in this chapter.

Explain how knee injuries can be prevented.

Compare and contrast male/female differences relative to anterior cruciate ligament (ACL) injuries.

Discuss etiological factors, symptoms and signs, and management procedures

for the injuries to the ligaments and menisci.

Identify the various etiological factors, symptoms and signs, and management procedures for injuries that occur in the patellofemoral joint and in the extensor mechanism.

Design appropriate rehabilitation protocols for the injured knee.

The Knee and Related Structures

Visit connect.mcgraw-hill.com for further exercises to apply your knowledge:

Clinical application scenarios covering assessment and recognition of knee injuries, etiology, symptoms and signs, and management of knee injuries, as well as rehabilitation for the knee Click and drag questions covering structural anatomy of the knee, assessment of knee injuries, and rehabilitation plan of the knee Multiple choice questions covering anatomy, assessment, etiology, management, and rehabilitation of knee injuries Selection questions covering rehabilitation plan for various injuries to the knee Video identifi cation of special tests for the knee injuries, rehabilitation techniques for the knee, and taping and wrapping for knee injuries Picture identifi cation of major anatomical components of the knee, rehabilitation techniques of the knee, and therapeutic modalities for management

pre23739_ch20_556-604.indd 556pre23739_ch20_556-604.indd 556 1/19/10 1:50:25 PM1/19/10 1:50:25 PM

www.mhhe.com/prentice14e Chapter Twenty The Knee and Related Structures 557

B ecause so many activities place extreme stress on the knee, it is one of the most traumatized joints in the physically active population. The knee is commonly considered a hinge joint because its two principal movements are fl exion and extension.

However, because rotation of the tibia is an essen-tial component of knee movement,

the knee is not a true hinge joint. The stability of the knee joint depends primarily on the ligaments, the joint capsule, and the muscles that surround the joint. The knee is designed primarily to provide stability in weight bearing and mobility in locomotion; however, it is espe-cially unstable laterally and medially.

ANATOMY OF THE KNEE Bones The knee joint complex consists of the femur, the tibia, the fi bula, and the patella (Figure 201). The distal end of the femur expands and forms the con-vex lateral and medial condyles, which are designed to articulate with the tibia and the patella. The articu-lar surface of the medial condyle is longer from front to back than is the surface of the lateral condyle. An-teriorly, the two condyles form a hollowed femoral groove, or trochlea, to receive the patella. The proxi-mal end of the tibia, the tibial plateau, articulates with the condyles of the femur. On this fl at tibial plateau are two shallow concavities that articulate with their respective femoral condyles and are divided by the

Muscles and ligaments provide the main source of stability in the knee.

popliteal notch. Separating these concavities, or ar-ticular facets, is a roughened area where the cruciate ligaments attach and from which a process commonly known as the tibial spine arises.

Patella The patella is the largest sesamoid bone in the human body. It is located in the tendon of the quad-riceps femoris muscle and is divided into three medial facets and a lateral facet that articulate with the femur (Figure 201). The lateral aspect of the patella is wider than the medial aspect. The patella articulates between the concavity provided by the femoral condyles. Track-ing within this groove depends on the pull of the quad-riceps muscle and patellar tendon, the depth of the femoral condyles, and the shape of the patella.

Articulations The knee joint complex consists of four articula-tions between the femur and the tibia, the femur and the patella, the femur and the fi bula, and the tibia and the fi bula.

Menisci The menisci (Figure 202A) are two oval (semilunar) fi brocartilages that deepen the articular facets of the tibia, cushion any stresses placed on the knee joint, and maintain spacing between the femoral condyles and tibial plateau. The consistency of the menisci is much like that of the intervertebral disks. They are located medially and laterally on the tibial plateau, or shelf. The menisci transmit one-half of the contact force in the medial compartment and an even higher percent-age of the contact load in the lateral compartment. The menisci help stabilize the knee, especially the medial meniscus, when the knee is fl exed at 90 degrees.

Medial Meniscus The medial meniscus is a C-shaped fi brocartilage, the circumference of which is attached fi rmly to the medial articular facet of the tibia and to the joint capsule by the coronary ligaments. Posteri-orly, it is also attached to fi bers of the semimembra-nous muscle.

Lateral Meniscus The lateral meniscus is more O-shaped and is attached to the lateral articular facet on the superior aspect of the tibia. The lateral meniscus also attaches loosely to the lateral articular capsule and to the popliteal tendon. The ligament of Wrisberg is the part of the lateral meniscus that proj-ects upward, close to the attachment of the posterior cruciate ligament. The transverse ligament joins the anterior portions of the lateral and medial menisci.

Meniscal Blood Supply Blood is supplied to each me-niscus by the medial genicular artery. Each meniscus can be divided into three circumfer-ential zones: the

Generally, the meniscus has a poor blood supply. FIGURE 201 The bones of the knee joint. A, Anterior

view. B, Posterior view.

Base of patellaArticular facets

Lateral condyleApexHead of fibula

Apex of patellaIntercondylareminence

Gerdys tubercle

Proximaltibiofibular joint

Lateral surface

Fibula

A B

FibulaTibia

Anteriorcrest

Tibial tuberosity

Medialcondyle

Lateralepicondyle

Femoral groove (trochlea)

Lateralepicondyle

Lateral condyle

FemurShaft

Medialepicondyle

Medialcondyle

Intercondylarfossa


558 Part Five Musculoskeletal Conditions

muscles, especially the hamstring muscle group, to stabilize the knee joint.

Posterior Cruciate Ligament Some portion of the pos-terior cruciate ligament is taut throughout the full range of motion. In general, the posterior cruciate ligament resists internal rotation of the tibia, prevents hyperextension of the knee, limits anterior translation of the femur during weight bearing, and limits poste-rior translation of the tibia in nonweight bearing.

Capsular and Collateral Ligaments Additional sta-bilization of the knee is provided by the capsular and collateral ligaments. Besides providing stability, they also direct movement in a correct path. Although they move in synchrony, they are divided into the medial and lateral complexes.

Medial Collateral Ligament The superfi cial posi-tion of the medial (tibial) collateral ligament (MCL) is separate from the deeper capsular ligament at the joint line. It attaches above the joint line on the me-dial epicondyle of the femur and below on the tibia, just beneath the attachment of the pes anserinus. The posterior aspect of the ligament blends into the deep posterior capsular ligament and semimembranous muscle. Fibers of the semimembranous muscle go through the capsule and attach to the posterior aspect of the medial meniscus, pulling it backward during knee fl exion. Some of its fi bers are taut through fl ex-ion and extension. Its major purpose is to prevent the knee from valgus and external rotating forces. The medial collateral ligament was thought to be the prin-cipal stabilizer of the knee in a valgus position when combined with rotation. It is now known that other structures, such as the anterior cruciate ligament, play an equal or greater part in this function. 68

Deep Medial Capsular Ligaments The deep medial capsular ligament is divided into three parts: the

red-red zone is the outer, or peripheral, one-third and has a good vascular supply; the red-white zone is the middle one-third and has minimal blood supply; and the white-white zone, on the inner one-third, is avas-cular (Figure 202B). 24

Stabilizing Ligaments The major stabilizing ligaments of the knee are the cruciate ligaments, the collateral ligaments, and the capsular ligaments (Figure 203).

Cruciate Ligaments The cruciate ligaments ac-count for a considerable amount of knee stability. They are two ligamentous bands that cross one an-other within the joint capsule of the knee. The an-terior cruciate ligament (ACL) attaches below and in front of the tibia; then, passing backward, it attaches laterally to the inner surface of the lateral condyle. The posterior cruciate ligament (PCL), the stronger of the two, crosses from the back of the tibia in an upward, forward, and medial direction and attaches to the anterior portion of the lateral surface of the medial condyle of the femur.

Anterior Cruciate Ligament The anterior cruciate ligament comprises three twisted bands: the an-teromedial, intermediate, and posterolateral bands. In general, the anterior cruciate ligament prevents the femur from moving posteriorly during weight bearing and limits anterior translation of the tibia in nonweight bearing. It also stabilizes the tibia against excessive internal rotation and serves as a secondary restraint for valgus or varus stress with collateral ligament damage.

When the knee is fully extended, the posterolat-eral section of the cruciate ligament is most tight. In fl exion the posterolateral fi bers loosen and the anteromedial fi bers tighten. 61 The anterior cruci-ate ligament works in conjunction with the thigh

FIGURE 202 A, Menisci and blood supply of the knee. B, Three vascular zones.

Anterior cruciateligament

Patella

Lateral meniscus

Posteriorcruciate

ligament

Medial meniscus

Lateral

Anterior

Posterior

Medial

A

Red-white zoneWhite-white zone

Red-red zone

B



and to the head of the fi bula. The lateral collateral ligament is taut during knee extension but relaxed during fl exion.

The arcuate ligament is formed by a thickening of the posterior articular capsule. Its posterior as-pect attaches to the fascia of the popliteal muscle and the posterior horn of the lateral meniscus.

Other structures that stabilize the knee laterally are the iliotibial band, popliteus muscle, and biceps femoris. The iliotibial band, a tendon of the tensor fasciae latae and gluteus medius, attaches to the lateral epicondyle of the femur and lateral tibial tu-bercle (Gerdys tubercle). It becomes tense during both extension and fl exion. The popliteus muscle stabilizes the knee during fl exion and, when con-tracting, protects the lateral meniscus by pulling it posteriorly.

anterior, medial, and posterior capsular ligaments. The anterior capsular ligament connects with the ex-tensor mechanism and the medial meniscus through the coronary ligaments. It relaxes during knee ex-tension and tightens during knee fl exion. The pri-mary purposes of the medial capsular ligaments are to attach the medial meniscus to the femur and to allow the tibia to move on the meniscus inferiorly. The posterior capsular ligament is sometimes called the posterior oblique ligament and attaches to the posterior medial aspect of the meniscus and inter-sperses with the semimembranous muscle. 4

Lateral Collateral Ligament and Related Structures The lateral (fi bular) collateral ligament (LCL) is a round, fi brous cord that is about the size of a pencil. It is attached to the lateral epicondyle of the femur

FIGURE 203 The ligaments of the knee. A, Anterior view. B, Posterior view. C, Capsular ligaments, posterior view.

Femur

Patellar surface

Lateral condyle

MedialcondylePosteriorcruciate ligament

Anteriorcruciate ligament

Fibula

Tibia

Lateral collateralligament

Medialcollateralligament

Patellarligament(cut)

Lateral meniscus

Transverseligament

Medialmeniscus

Anterior

Medial condyle

Posteriorcruciate ligament

Ligamentof Humphery

Anteriorcruciate ligament

Medial collateralligament

Medial meniscus Lateral

meniscus

Lateralcollateralligament

Articularcartilageof tibia

Posterior

A B

Posterior obliqueligamentMedial

capsularligament

C

Arcuate ligament

Popliteus m.(cut)



band, the patellar tendon, and the lateral patellar ret-inaculum. The superfi cial MCL and the medial patel-lar retinaculum reinforce the anteromedial corner.

Synovial membrane lines the inner surface of the joint capsule, except posteriorly, where it passes in front of the cruciates, making them extrasynovial (Figure 204).

Knee Musculature For the knee to function properly, a number of muscles must work together in a complex manner. The following is a list of knee actions and the mus-cles that initiate them (Figure 205). Table 201 lists all of the muscles that produce movement at the knee.

Knee fl exion is executed by the biceps femoris, semitendinosus, semimembranosus, gracilis, sar-torius, gastrocnemius, popliteus, and plantaris muscles. Knee extension is executed by the quadriceps muscle of the thigh, consisting of three vastithe vastus medialis, vastus lateralis, and vastus intermediusand by the rectus femoris. External rotation of the tibia is controlled by the biceps femoris. The bony anatomy also produces external tibial rotation as the knee moves into extension. Internal rotation is accomplished by the popliteal, semitendinosus, semimembranosus, sartorius, and gracilis muscles. Rotation of the tibia is limited and can occur only when the knee is in a fl exed position. The iliotibial band on the lateral side primarily functions as a dynamic lateral stabilizer.

Bursae A bursa is composed of pieces of synovial tissue separated by a thin fi lm of fl uid. The function of

The biceps femoris muscle also stabilizes the knee laterally by inserting into the fi bular head, iliotibial band, and capsule.

Joint Capsule The articular surfaces of the knee joint are com-pletely enveloped by the largest joint capsule in the

body (Figure 204). Anteriorly, the joint capsule extends up-ward underneath the patella to form the suprapatellar pouch. The inferior portion contains the infrapa-tellar fat pad and the infrapatellar bursa. Medially, a thickened section of the capsule forms the deep portion of the medial collateral ligament. Posteriorly, the capsule forms two pouches that cover the femoral condyles and the tibial plateau.

The capsule thickens medially to form the posterior oblique ligament and laterally to form the arcuate ligament (see Figure 203C).

The joint capsule is divided into four regions: the posterolateral, posteromedial, anterolateral, and an-teromedial. Each of these four corners of the cap-sule is reinforced by other anatomical structures. The posterolateral corner is reinforced by the iliotibial band, the popliteus, the biceps femoris, the LCL, and the arcuate ligament. The MCL, the pes anserinus tendons, the semimembranosus, and the posterior oblique ligament reinforce the posteromedial corner. The anterolateral corner is reinforced by the iliotibial

201

Cli

nica

l App

lica

tion

Exe

rcis

e

A tennis player injures her knee during a match. As she hits a forehand stroke, her knee is in full extension and she feels pain in it as she rotates on the follow-through. She feels some diffuse pain around her knee joint and is concerned that she has sprained a ligament.

? In a position of full extension, which of the supporting ligaments are taut? Which ligaments are most likely to be injured in this position?

Femur

Bursa under lateral head of gastrocnemius

Meniscus

Tibia

Joint cavity

Infrapatellar fat pad

Synovial membrane

Suprapatellarbursa (pouch)

Quadriceps femoris

Quadricepsfemoris tendon

Patellar ligament

PatellaPrepatellar bursa

Superficial infrapatellar bursa

Deep infrapatellar bursa

Articular cartilage

Joint capsule

FIGURE 204 Sagittal cross section of the knee, showing the location of bursae and synovial membranes.


FIGURE 205 Muscles of the knee. A, Anterior view. B, Posterior view. C, Deep posterior view.

Iliotibial band

Long head Short head

Biceps femorisHamstring group

Semitendinosus

Semimembranosus

Adductor magnus

Gracilis

Vastus lateralis

Gastrocnemius(lateral head)Gastrocnemius

(medial head)

A B

Iliotibialband

SartoriusQuadriceps femoris

Rectus femoris

Vastus lateralis

Vastus medialisoblique

Quadriceps femoristendon

Patella

Patellar ligament

Gracilis

Pes anserinusSartoriusGracilisSemitendinosus

Vastus intermedius(beneath rectusfemoris)

Heads of gastrocnemius(cut)

Popliteus

C

Plantaris

Soleus

TABLE 201 Muscles of the Knee

Muscle Origin InsertionMuscle Action (nonweight bearing) Innervation

Sartorius Anterior superior iliac spine

Proximal medial surface of the tibia, below the tuberosity

Knee fl exion and internal rotation

Femoral (L2, L3, L4)

Quadriceps femoris: Rectus femoris Anterior inferior iliac

spine and just above the acetabulum of the os coxae

Tibial tuberosity, via the patella and the

patellar ligamentKnee extension Femoral (L2, L3, L4)

Vastus lateralis Greater trochanter and lateral lip of the linea

aspera of the femur Vastus medialis Medial lip of the linea

aspera of the femur Vastus intermedius Anterior surface of

the shaft of the femurHamstrings: Biceps femoris

Long head: ischial tuberosityShort head: lateral lip of the linea aspera

Lateral surface of the head of the fi bula and

the lateral condyle of the tibia

Knee fl exion and external rotation

Sciatic (L5, S1, S2)

Semitendinosus Ischial tuberosity Medial surface of the proximal end of the tibia


Tibial (S1, S2)

Semimembranosus Ischial tuberosity Medial surface of the proximal end of the

tibia


Tibial (S1, S2)

Popliteus Lateral condyle of the femur

Posterior surface of the tibia below the

tibial plateau


Tibial (L4, L5, S1)

Gastrocnemius Lateral head: posterior lateral condyle of the

femurMedial head: popliteal surface of the femur

above medial condyle

Posterior surface of the calcaneous

Knee fl exion Tibial (S1, S2)

Plantaris Lateral supracondylar ridge of the femur

Posterior surface of the calcaneous

Knee fl exion Tibial (L4, L5, S1)

Gracilis Inferior ramus of pubis Medial surface of the tibia


Obturator (L3, L4)



Tibial nerve

Commonperonealnerve

Superficial peronealnerve

Posterior view

FIGURE 206 Nerve supply to the knee.

FIGURE 207 Blood supply of the knee. A, Anterior arteries. B, Posterior arteries. C, Venous supply.

Femoralvein

Poplitealvein

Small saphenousvein

C Medial view

Superior lateralgenicular artery

Superiormedial

genicularartery

Inferior lateralgenicular artery

Inferiormedial

genicular artery

Popliteal artery

Fibular artery

A Anterior view B Posterior view

a bursa is to reduce the friction between anatomi-cal structures. Bursae are found between muscle and bone, tendon and bone, tendon and liga-ment, and so forth. As many as two dozen bursae have been identifi ed around the knee joint. The suprapatellar, prepatellar, infrapatellar, pretibial, and gastrocnemius bursae are perhaps the most commonly injured about the knee joint (see Figure 204).

Fat Pads There are several fat pads around the knee. The infrapatellar fat pad is the largest. It serves as a cushion to the front of the knee and separates the patellar tendon from the joint capsule. Other major fat pads in the knee include the anterior and pos-terior suprapatellar and the popliteal. Some fat pads occupy space within the synovial capsule (see Figure 204).

Nerve Supply The tibial nerve innervates most of the hamstrings and the gastrocnemius. The common peroneal nerve innervates the short head of the biceps femoris and then courses through the popliteal fossa and wraps around the proximal head of the fi bula. Because the peroneal nerve is exposed at the head of the fi bula, contusion of the nerve can cause distal sensory and motor defi cits. The femoral nerve innervates the quadriceps and the sartorius muscles (Figure 206).

Blood Supply The main blood supply to the knee comes from the popliteal artery, which stems from the femoral ar-tery. From the popliteal artery, four branches supply the knee: the medial and lateral superior genicular and medial and lateral inferior genicular arteries (Figure 207A&B). Blood drains via the small sa-phenous vein into the popliteal vein and then to the femoral vein (Figure 207C).

FUNCTIONAL ANATOMY Movement between the tibia and the femur in-volves the physiological motions of fl exion, ex-tension, and rotation as well as arthrokinematic motions, includ-ing rolling and gliding. As the tibia extends on the femur, the tibia glides and rolls anteriorly. If the femur is extending on the tibia, gliding occurs in an anterior direction, whereas rolling occurs posteriorly.

Axial rotation of the tibia relative to the femur is an important component of knee motion. In the screw home mechanism of the knee, as the knee extends, the tibia externally rotates. Rotation occurs because the medial femoral condyle is larger than the lateral condyle. Thus, when weight bearing, the tibia must rotate externally to achieve full exten-sion. The rotational component gives a great deal of stability to the knee in full extension. When weight bearing, the popliteus muscle must contract and ex-ternally rotate the femur to unlock the knee so that fl exion can occur.

The capsular ligaments are taut during full ex-tension and somewhat more lax during fl exion. This is particularly true of the lateral collateral liga-ment; however, portions of the medial collateral

Major actions of the knee:

Flexion Extension Rotation Rolling Gliding



ligament relax as fl exion occurs. Relaxation of the more superfi cial collateral ligaments allows rotation to occur. In contrast, the deeper capsular ligament tightens to prevent excessive rotation of the tibia.

During the last 15 degrees of extension, the tibia externally rotates and the anterior cruciate liga-ment unwinds. In full extension the posteriolateral portion of anterior cruciate ligament is taut, and it loosens during fl exion. As the femur glides on the tibia, the posterior cruciate ligament becomes taut and prevents further gliding. In general, the anterior cruciate ligament stops excessive inter-nal rotation, stabilizes the knee in full extension, and prevents hyperextension. The posterior cruci-ate ligament prevents excessive internal rotation of the tibia, limits anterior translation of the femur on the fi xed tibia, and limits posterior translation of the tibia in nonweight bearing. 31

In complete fl exion, approximately 140 degrees, the range of the knee movement is limited by the extremely shortened position of the hamstring muscles, the extensibility of the quadriceps muscles, and the bulk of the hamstring muscles. In this posi-tion, the femoral condyles rest on their correspond-ing menisci at a point that permits a small degree of inward rotation.

The patella aids the knee during extension by lengthening the lever arm of the quadriceps mus-cle. 26 It distributes the compressive stresses on the femur by increasing the contact area between the patellar tendon and the femur. 63 It also pro-tects the patellar tendon against friction. During full extension, the patella lies slightly lateral and proximal to the femoral groove, or trochlea. At 20 degrees of knee fl exion, there is tibial rotation, and the patella moves into the trochlea. At 30 de-grees, the patella is most prominent. At 30 degrees and more, the patella moves deeper into the tro-chlea. At 90 degrees, the patella again becomes positioned laterally. When knee fl exion is 135 de-grees, the patella has moved laterally beyond the trochlea. 63

The Knee in the Kinetic Chain The knee is part of the kinetic chain that was dis-cussed in Chapter 16. It is directly affected by mo-tions and forces occurring to and being transmitted from the foot, ankle, and lower leg. In turn, the knee must transmit forces to the thigh, hip, pelvis, and spine. Abnormal forces that cannot be distrib-uted must be absorbed by the tissues. When the foot is in contact with the ground, a closed kinetic chain exists. In a closed kinetic chain, forces must either be transmitted to proximal segments or be absorbed in a more distal joint. The inability of this closed system to dissipate these forces typically leads to a breakdown in some part of the system. As part of

the kinetic chain, the knee joint is susceptible to in-jury resulting from the absorption of these forces. 89

ASSESSING THE KNEE JOINT It is the responsibility of the team physician to pro-vide a medical diagnosis of the severity and exact nature of a knee injury. Although the physician is charged with the fi nal medical diagnosis, the athletic trainer is usually the fi rst person to observe the in-jury; therefore, he or she is charged with clinical diag-nosis and immediate care. The most important aspect of understanding what pathological process has taken place is to become familiar with the traumatic sequence and mechanisms of injury, either through having seen the injury occur or through learning its history (Figure 208). 18 Often, the team physician is not present when the injury occurs, and the athletic trainer must relate the pertinent information. 68

History To determine the history and major complaints in-volved in a knee injury, the athletic trainer should ask the following questions.

Current Injury

What were you doing when the knee was hurt? What position was your body in? Did the knee collapse? Did you hear a noise or feel any sensation at the time of injury, such as a pop or crunch? (A pop could indicate an anterior cruciate tear, a crunch could be a sign of a torn meniscus, and a tearing sensation might indicate a capsular tear.) Could you move the knee immediately after the injury? If not, was it locked in a bent or ex-tended position? (Locking could mean a menis-cal tear.) After being locked, how did it become unlocked? Did swelling occur? If yes, was it immediate, or did it occur later? (Immediate swelling could in-dicate a cruciate or tibial fracture, whereas later

FIGURE 208 It is extremely important that the se-quence and mechanism of a knee injury be known before the pathological process can be understood.



Does the patient walk with a limp, or is the walk free and easy? Is the patient able to fully extend the knee during heel strike? Can the patient fully bear weight on the affected leg? Can the patient perform a half-squat to extension? Can the patient go up and down stairs with ease? (If stairs are unavailable, stepping up on a box or stool will suffi ce.) Does the patient have full range of motion (full extension to 0 and 135 of fl exion)?

Leg Alignment The patient should be observed for leg alignment. Anteriorly, the patient should be evaluated for genu valgum, genu varum, and the position of the patella. Next, the patient should be observed from the side to ascertain conditions such as the hyperfl exed or hyperextended knee.

Deviations in normal leg alignment may be a factor in a knee injury but should always be con-sidered as a possible cause. Like alignment in any other body segment, leg alignment differs from person to person; however, obvious discrepan-cies could predispose the individual to an acute or chronic injury.

Anteriorly, with the knees fully extended, the following points should be noted:

Are the patellas level with each other? Are the patellas facing inward (squinting patella)?

Looking at the patients knees from the side, these questions should be answered:

Are the knees fully extended with only slight hyperextension? Are both knees equally extended?

Leg Alignment Deviations That May Predispose to Injury Four major leg deviations could adversely affect the knee and patellofemoral joints: patellar malalign-ment, genu val-gum (knock-knees), genu varum (bowlegs), and genu recur-vatum (hyperex-tended knees).

Patellar malalignment In patella alta, the patella sets in a more superior position than normal when the patient is standing. The ratio of patellar tendon length to the height of the patella is greater than the normal 1:1 ratio. In patella alta, the length of the patellar tendon is 20 percent greater than the height of the patella. In patella baja , the patella sets in a more in-ferior position than normal

Leg deviations:

Patella alta Patella baja Genu valgum Genu varum Genu recurvatum

patella alta Patella more superior.

patella baja Patella more inferior.

swelling could indicate a capsular, synovial, or meniscal tear.) Where was the pain? Was it local, all over, or did it move from one side of the knee to the other? Have you hurt the knee before? (Refer to Re- current or Chronic Injury, which follows)

When fi rst evaluating the injury, the athletic trainer should observe whether the patient is able to support body weight fl atfooted on the injured leg or whether the patient needs to stand and walk on the toes. Toe walking is an indication that the patient is holding the knee in a splinted position to avoid pain or that the knee is being held in a fl exed position by a piece of a torn or dislocated meniscus. In fi rst-time acute knee sprains, fl uid and blood effusion is not usually apparent until after a twenty-four-hour period. However, in an anterior cruciate liga-ment sprain, a hemarthrosis may occur during the fi rst hour after injury. Swelling and ecchymosis will occur unless the effusion is arrested through the use of compression, elevation, and cold packs.

Recurrent or Chronic Injury

What is your major complaint? When did you fi rst notice the condition? Is there recurrent swelling? Does the knee ever lock or catch? (If yes, it may be a torn meniscus or a loose body in the knee joint.) Is there severe pain? Is it constant, or does it come and go? Do you feel any grinding or grating sensations? (If yes, it could indicate chondromalacia or trau-matic arthritis.) Does your knee ever feel like it is going to give way, or has it actually done so? (If yes and often, it may be a capsular, cruciate, or meniscal tear; a loose body; or a subluxating patella.) What does it feel like to go up and down stairs? (Pain may indicate a patellar irritation or menis-cal tear.) What past treatment (past surgery, physical therapy, etc.), if any, have you received for this condition?

Observation A visual examination should be performed after the major complaints have been determined. The patient should be observed in a number of situations: walking, half-squatting, and going

up and down stairs. The leg also should be observed for alignment and symmetry or asymmetry.

If possible, the patient with an injured knee should be observed in the following actions:

Walking Half-squatting Going up and down stairs



position. Four components should be assessed when looking at patellar orientation: the glide component, the tilt component, the rotation component, and the anteroposterior tilt component. The glide compo-nent assesses whether the patella is deviated either laterally or medially to the center of the trochlear groove of the femur (Figure 2010). Glide should be assessed both statically and dynamically. Patellar tilt is determined by comparing the height of the me-dial patellar border with the lateral patellar border (Figure 2011). If the medial border is more anterior than the lateral border, a positive lateral tilt exists. Patellar rotation is identifi ed by assessing the devia-tion of the longitudinal axis (line drawn from supe-rior pole to inferior pole) of the patella relative to the femur (Figure 2012). The point of reference is the inferior pole. Thus, if the inferior pole is more lateral than the superior pole, a positive external ro-tation exists. The anteroposterior tilt component must be assessed laterally to determine if a line drawn from the inferior patellar pole to the superior pa-tellar pole is parallel to the long axis of the femur (Figure 2013). If the inferior pole is posterior to the superior pole, the patient has a positive anteroposte-rior tilt component. 68

Genu valgum The causes of genu valgum, or knock-knees, can be multiple (Figure 2014A). Nor-mally, toddlers and very young children display knock-knees. When the legs have strengthened and the feet have become positioned more in

genu valgum Knock-knees.

and the ratio of patellar tendon length to the height of the patella is less than the normal 1:1 ratio.

A patella that is rotated inward or outward from the center may be caused by a complex set of cir-cumstances. For example, a combination of genu recurvatum, genu varum, and internal rotation, or anteversion, of the hip and internal rotation of the tibia could cause the patella to face inward. Inter-nal rotation of the hip also may be associated with knock-knees, along with external rotation of the tibia, or tibial torsion. Patients who toe-out when they walk may have an externally rotated hip, or ret-roversion. The normal angulation of the femoral neck after eight years of age is 15 degrees; an increase of this angle is considered anteversion, and a decrease is considered retroversion. If an abnormal angulation seems to be a factor with the patella, malalignment or tibial torsion angles should be measured. Measuring for tibial torsion, femoral anteversion, and femoral retroversion Tibial torsion is determined by having the patient kneel on a stool with the foot re-laxed. An imaginary line is drawn along the center of the thigh and lower leg, bisecting the middle of the heel and the bottom of the foot. Another line starts at the center of the middle toe and crosses the center of the heel. The angle formed by the two lines is mea-sured (Figure 209); an angle measuring more or less than 15 degrees is a sign of tibial torsion.

Femoral anteversion or retroversion can be deter-mined by the number of degrees the thigh rotates in each direction. As a rule, external rotation and in-ternal rotation added together equal close to 100 de-grees. If internal rotation exceeds 70 degrees, there may be anteversion of the hip (see Chapter 21).

Hyperextension of the knee may result in inter-nal rotation of the femur and external rotation of the tibia. Internal rotation at the hip is caused by weak external rotator muscles or foot pronation.

Patellar orientation Patellar orientation refers to the positioning of the patella relative to the tibia. 68 As-sessment should be done with the patient in supine

FIGURE 209 Measuring for tibial torsion.

FIGURE 2010 Glide component. A, Normal. B, Positive medial glide.

Medial

B

Lateral

A



line with the pelvis, the condition is usually corrected. Commonly associated with knock-knees are pronated feet. Genu valgum places chronic tension on the liga-mentous structures of the medial part of the knee, ab-normal compression of the lateral aspect of the knee surface, and abnormal tightness of the iliotibial band. One or both legs may be affected, and the hips exter-nal rotator muscles may be weak.

Genu varum The two types of genu varum, or bowlegs, are structural and functional (Fig -ure 2014B). The structural type, which is seldom seen in young patients, re-fl ects a deviation of the femur and tibia. The more common functional, or postural, type usually is as-sociated with knees that are hyperextended and fe-murs that are internally rotated. Often, correcting genu recurvatum also corrects genu varum.

Genu recurvatum Genu recurvatum (Fig-ure 2014C), or hyperextended knees, commonly occurs as a compensation for lordosis, or swayback (see Figure 2510). 49 There is notable weakness and stretching of the ham-string muscles. Chronic

genu varum Bowlegs.

genu recurvatum Hyperextended knees.

FIGURE 2012 Rotation component. A, Normal B, Positive external rotation.

A

Lateral

B

Medial

FIGURE 2011 Tilt component. A, Normal. B, Positive medial tilt.

A

B

Lateral

Medial

FIGURE 2013 Anteroposterior tilt (lateral view). A, Normal. B, Positive inferior anteroposterior tilt.

A

Posterior

B

Anterior



FIGURE 2014 Leg alignment. A, Genu valgum. B, Genu varum. C, Genu recurvatum.

A B C

hyperextension can produce undue anterior pres-sure on the knee joint and posterior ligaments and tendons.

Knee Symmetry The athletic trainer must establish whether both of the patients knees look the same:

Do the knees appear symmetrical? Is one knee obviously swollen? Is muscle atrophy apparent?

Leg-Length Discrepancy Discrepancies in leg length can occur as a result of many causes, either anatomi-cal or functional (see Chapter 21 for a detailed dis-cussion). True anatomical leg length can be measured from the anterior superior iliac spine (ASIS) to the lateral malleolus. Functional leg length can be mea-sured from the umbilicus to the medial malleolus.

Anatomical differences in leg length can cause problems in all weight-bearing joints. Functional differences can be caused by rotations of the pelvis or malalignments of the spine.

Palpation Bony Palpation The bony structures of the knee are palpated for pain and deformities that might indicate a fracture or dislocation. The patient sits on the edge of the treatment table or a bench. With the patients knee fl exed to 90 degrees, the athletic trainer pal-pates the following bony structures:

Medial Aspect Medial tibial plateau Medial femoral condyle Medial epicondyle Adductor tubercle Gerdys tubercle

Lateral Aspect Lateral tibial plateau Lateral femoral condyle

Lateral epicondyle Head of the fi bula

Anterior Aspect Patella Tibial tuberosity

Patella Superior patellar border (base) Inferior patellar border (apex) Around periphery with the knee relaxed Around periphery with the knee in full extension

Soft-Tissue Palpation

The following soft-tissue structures should be palpated:

Anterior Vastus medialis Vastus lateralis Rectus femoris Quadriceps tendon Sartorius Medial patellar plica Patellar tendon Anterior joint capsule

Medial Medial collateral ligament, superfi cial portion Medial collateral ligament, capsular portion Pes anserinus insertion (sartorius, gracilis, semitendinosus) Medial joint capsule

Posterior Semitendinosus Popliteus Medial and lateral heads of the gastrocnemius Biceps femoris Posterior oblique ligament



after injury as possible. The injured knee and unin-jured knee are tested and contrasted to determine any differences in their stability.

Determination of the degree of instability is made by feeling the endpoint during stability test-ing. As stress is ap-plied to a joint, there will be some motion, which is limited by an intact ligament. In a normal joint, the end-point will be abrupt with little or no give and no reported pain. With a grade 1 sprain, the endpoint will still be fi rm with little or no instability, and some pain will be in-dicated. With a grade 2 sprain, the endpoint will be soft with some instability present and a moderate amount of pain. In a grade 3 complete rupture, the endpoint will be very soft with marked instability, and pain will be severe initially, then mild. 48

The use of magnetic resonance imaging (MRI) as a diagnostic tool has aided tremendously in the classifi cation of ligamentous sprains. Despite its ex-pense, MRI is being widely used by physicians to detect ligament injuries.

Table 202 provides a summary of the various tests and what a positive test indicates in terms of the injured structures.

Classifi cation of Knee Joint Instabilities A good deal of controversy exists over the most appropriate terminology for classifying instabilities in the knee joint. 76 For years the American Orthopedic Society for Sports Medicine has classifi ed knee laxity as ei-ther a straight or a rotatory instability. Straight insta-bility implies laxity in a single directionmedial, lateral, anterior, or posterior. Rotatory instability refers to excessive rotation of the tibial plateau relative to the femoral condyles and is identifi ed as anterolat-eral, anteromedial, posterolateral, or, rarely, postero-medial. It is not unusual to see combined instabilities, depending on the structures that have been injured. This classifi cation system is still the most widely used and accepted by athletic trainers (Table 203).

The concept of tibial translation has been pro-posed. 76 Translation refers to the amount of gliding of the medial tibial plateau as compared with the lateral tibial plateau relative to the femoral condyles. For example, in anterolateral

A marathon runner is com-plaining of nonspecifi c

anterior knee pain. She in-dicates that not only do her knees hurt during her train-

ing sessions but they also bother her when ascending or descending stairs, when

she squats and then tries to stand, and when she sits for

long periods of time.

? What anatomical and biomechanical factors that

might be contributing to the patients anterior knee pain

should the athletic trainer assess?

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translation Amount of gliding of the medial tibial plateau.

Lateral Lateral collateral ligament Iliotibial band Lateral joint capsule Arcuate complex

Palpation of Swelling Patterns Palpation of joint ef-fusion and associated swelling patterns are critical in assessing knee injury (Figure 2015). Swelling may be intracapsular (inside the joint capsule) or extracap-sular (outside the joint capsule). Intracapsular swell-ing may also be referred to as a joint effusion. A moderate amount of swelling that occurs immedi-ately following injury and that is caused by synovial

fl uid and by blood in the joint is called a hemarthrosis. A hemarthrosis can only be

identifi ed by having the team physician aspirate the joint with a needle. With intracapsular joint effusion, the fl uid in the joint can be moved manually from one side of the joint to the other. In a sweep maneuver, pressure applied from superior to the patella down-ward moves fl uid into the center of the joint capsule; then pressure from the medial side of the joint line will cause a bulging laterally. Joint effusion can also cause what has been referred to as a ballotable patella. With the knee in full extension and the quadriceps relaxed, a release of downward pressure on the pa-tella sitting on top of the joint capsule causes the patella to bounce back to its normal position.

Extracapsular swelling from bursitis, tendinitis, or injury to one of the collateral ligaments tends to localize over the injured structure and then gradu-ally migrate downward toward the foot and ankle because of the effects of gravity.

Special Tests for Assessment of Knee Joint Instability Both traumatic and overuse injury to the knee can produce ligamentous instability. It is advisable that the injured knees stability be evaluated as soon

hemarthrosis Blood in a joint cavity.

FIGURE 2015 Typical swelling sites around the knee.

Soft tissue(medial)

Prepatellarbursa

Joint effusion

Soft tissue(lateral)

Infrapatellarbursa



Collateral Ligament (Valgus and Varus) Stress Tests Valgus and varus stress tests are intended to reveal laxity of the medial and lateral stabilizing complexes, especially the collateral ligaments. The patient lies supine with the leg extended. To test the medial side, the athletic trainer holds the ankle fi rmly with one hand while placing the other hand over the head of the fi bula. The athletic trainer then places a force inward in an attempt to open the side of the knee. This valgus stress is applied with the knee fully extended, or at 0 degrees, and at 30 de-grees of fl exion (Figure 2016A&B). The examina-tion in full extension tests the MCL, posteromedial capsule, and cruciates. At 30 degrees of fl exion, the MCL is isolated. The athletic trainer reverses hand positions and tests the lateral side with a varus force on the fully extended knee and then with 30 de-grees of fl exion (Figure 2016C&D). With the knee

rotatory instability, the anterior translation of the lateral tibial plateau would be much greater than the more stable medial tibial plateau. The amount of anterior translation is determined by the integrity of the anatomical restraints that normally restrict excessive translation. More ligamentous, tendinous, and capsular structures will be damaged as the se-verity of the injury increases.

TABLE 203 Classifi cation of Instabilities

Straight Instabilities Rotatory Instabilities

Medial AnterolateralLateral AnteromedialAnterior PosterolateralPosterior

TABLE 202 Knee Stability Tests

Test If Positive

Valgus stress test at 0 Torn MCL and possibly ACL, PCL, PMCValgus stress test at 20/30 Torn MCL (if grade 3 check ACL, PCL, PMC)Varus stress test at 0 Torn LCL and possibly ACL, PCL, PLCVarus stress test at 20/30 Torn LCL (if grade 3 check ACL, PCL, PLC)Lachman drawer test (20/30 fl exion) Torn ACL, PCL (positive more often than anterior drawer

because hamstrings are relaxed and medial meniscus/collateral ligaments do not block anterior displacement at 20)

Anterior drawer test (neutral) Torn ACLAnterior drawer test (15 ER) Torn PMC, ACL, and possibly MCLAnterior drawer test (30 IR) Torn PLC, ACLPivot-shift tests (Galaway and McIntosh) Torn ACL, ALC Extension/IR/valgus (tibia subluxated) fl exion (tibia reduces at 20)Slocums test Torn ACL, ALC Sidelying extension/IR/valgus (tibia subluxated) fl exion (tibia reduces at 20)Jerk test (Hughston) Torn ACL, ALC Flexion/IR/valgus (tibia reduced) extension (tibia subluxates at 20)Losee test Torn ACL, ALC 45 fl exion/ER/valgus (tibia subluxated anteriorly) extension (tibia reduces at 20)Flexion-rotation drawer test Torn ACL 45 fl ex (tibia subluxated anteriorly/femur ER) fl exion (tibia reduces posteriorly/ femur IR)Posterior drawer test 90 Torn PCLExternal rotation recurvatum test (tibia ER) Torn PCL, PLCPosterior sag test 90 Torn PCLReverse pivot-shift test (Jakob) Torn PCL Extension (tibia reduced) fl exion (tibia subluxated posteriorly with ER)McMurrays test (IR) Torn LM (ER) Torn MMApleys grinding test Torn MMThessalys Test Torn LM or MM

ACL 5 anterior cruciate ligament; ALC 5 anterior lateral corner; ER 5 external rotation; IR 5 internal rotation; LCL 5 lateral collateral ligament; LM 5 lateral meniscus; MCL 5 medial collateral ligament; MM 5 medial meniscus; PCL 5 posterior cruciate ligament; PLC 5 posterior lateral corner; PMC 5 posterior medial corner.



upper portion of the leg immediately below the knee joint. The athletic trainer positions his or her fi n-gers in the popliteal space of the affected leg, with the thumbs on the medial and lateral joint lines (Figure 2018). The athletic trainer places his or her index fi ngers on the hamstring tendon to ensure that it is relaxed before the test is administered. 59 If the tibia slides forward from under the femur, this is considered a positive anterior drawer sign. 47 Slocums test should be performed with the patients leg rotated internally 30 degrees and externally 15 degrees (Figure 2018). Anterior translation of the tibia when the leg is externally rotated is an in-dication that the posteromedial aspect of the joint capsule, the anterior cruciate ligament, or possibly the medial collateral ligament is torn. Movement when the leg is internally rotated indicates that the

extended, the LCL and posterolateral capsule are examined. At 30 degrees of fl exion, the LCL is iso-lated. 48 NOTE: The lower limb should be in a neutral position with no internal or external rotation.

Apley Distraction Test With the patient in the same position as for the Apley compression test, the ath-letic trainer applies traction to the lower leg while rotating it back and forth (Figure 2017). This ma-

neuver distinguishes collateral ligamentous tears from capsular and meniscal tears. If the capsule or liga-ments are affected, pain will occur; if the meniscus is torn, no pain will occur from the traction and rotation. 48

Anterior Cruciate Ligament Tests A number of tests are used to establish the integrity of the cruciate

ligaments. 76 They are the drawer test at 90 degrees of fl exion, the Lachman drawer test, the pivot-shift test, the jerk test, and the fl exion-rotation drawer test.

Drawer Test at 90 Degrees of Flexion The patient lies on the treatment table with the injured leg fl exed. The athletic trainer stands facing the anterior aspect of the patients leg, with both hands encircling the

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e A football running back is hit on the lateral surface of his knee by an opponent making a tackle. He has signifi cant pain and some immediate swelling on the medial surface of his knee. The athletic trainer suspects that the athlete has sus-tained a sprain of the MCL.

? What are the most appropriate tests that the athletic trainer should do to determine the exact nature and extent of the injury?

FIGURE 2016 Valgus and varus knee stress tests. A , Valgus at 0 degrees. B , Valgus at 30 degrees. C , Varus at 0 degrees. D, Varus at 30 degrees. S 5 Stabilize

A B

C D

S

S

S

S

FIGURE 2017 The thigh is stabilized with the examiners knee while the lower leg is distracted and rotated.



tends to mask the real extent of injury. The Lach-man drawer test is administered by positioning the knee in approximately 30 degrees of fl exion. The athletic trainer uses one hand to stabilize the leg by grasping the distal end of the thigh and the other hand to grasp the proximal aspect of the tibia and attempts to move it anteriorly. One problem with the Lachman test is that, if the patient is very large or if the athletic trainer has small hands, it is diffi cult to perform this test effi ciently. 36 Several alternative methods may be used. First, a tightly rolled towel or other support can be placed under the femur and the athletic trainer can use one hand to stabilize the femur and the other to anteriorly translate the tibia (Figure 2019B). A second alternative is to slide the lower leg off the edge of the examining table with the knee and femur supported by the edge of the table. Again, one hand should be used to stabilize the femur and the other to anteriorly translate the tibia (Figure 2019C). Finally, the patient may be placed prone with the knee and lower leg just off the edge of the table. This position minimizes any posterior sag of the tibia that can mask a positive test. 56 Using the table to stabilize the femur, the athletic trainer can anteriorly translate the tibia (Figure 2019D). A positive Lachman test indicates damage to the ante-rior cruciate.

Pivot-Shift Test The pivot-shift test is designed to determine anterolateral rotary instability (Fig-ure 2020A). It is most often used in chronic condi-tions and is a sensitive test when the anterior cruciate ligament has been torn. The patient lies supine. The

anterior cruciate ligament and posterolateral cap-sule may be torn. Anterior translation of inch, to inch, and inch or more (1.25 cm, 1.25 to 1.9 cm, and 1.9 cm or more) corresponds to grades 1, 2, and 3, respectively. 76

Lachman Drawer Test The Lachman drawer test is considered to be a better test than the drawer test at 90 degrees of fl exion (Figure 2019). 83 This prefer-ence is especially true for examinations immediately after injury. One reason for using it immediately after an injury is that it does not force the knee into the painful 90-degree position but tests it at a more comfortable 20 to 30 degrees. Another reason for its increased popularity is that it reduces the restriction created by the hamstring muscles. 56 That contrac-tion causes a secondary knee-stabilizing force that

FIGURE 2018 Anterior drawer test for cruciate laxity. With the knee fl exed to 90 degrees, apply an anterior force fi rst with the foot pointing straight. Slocums test is performed with the knee at 90 degrees and the leg internally rotated, then with the knee at 90 degrees and the leg externally rotated.

FIGURE 2019 Lachman drawer test for anterior cruciate laxity. A, Standard Lachman drawer test. B, Alternative technique one. C, Alternative technique two. D, Prone Lachman drawer test. ( S 5 Stabilize)

A B

C

S

S D



subluxated anteriorly. As the knee is extended, the tibia reduces at about 20 degrees (Figure 2022B).

Posterior Cruciate Ligament Tests Tests for post-erior cruciate ligament instability include the post-erior drawer test, the external rotation recurvatum test, and the posterior sag test.

athletic trainer uses one hand to press against the head of the fi bula and the other to grasp the patients ankle. To start, the lower leg is internally rotated and the knee is fully extended. The thigh is then fl exed 30 degrees at the hip while the knee is also fl exed, and the athletic trainer applies a simultaneous valgus force and axial load with his or her upper hand. If the anterior cruciate ligament is damaged, the lateral tib-ial plateau will be subluxated in the fully extended position. As the knee is fl exed to between 20 and 40 degrees, the lateral tibial plateau will reduce itself, producing a palpable shift or clunk. 76 A variation of the pivot-shift test is Slocums test, which is done in a side-lying position (Figure 2020B). 76

Jerk Test The jerk test reverses the direction of the pivot-shift test. 48 The position of the knee is identical to that for the pivot-shift test except that the knee is moved from a position of fl exion into extension with the lateral tibial plateau in a reduced position.

If there is anterior cru-ciate insuffi ciency, as the knee moves into extension the tibia will subluxate at about 20 degrees of fl exion, once again produc-ing a palpable shift or clunk (Figure 2021).

Flexion-Rotation Drawer Test With this test, the lower leg is cradled with the knee fl exed between 15 and 30 de-grees. At 15 degrees, the tibia is subluxated anteriorly with the femur externally ro-tated. As the knee is

fl exed to 30 degrees, the tibia reduces posteriorly and the femur rotates internally (Figure 2022A). 76 Losees test is similar to the fl exion-rotation drawer test, but it is done in a side-lying position. It begins at 45 degrees of fl exion with external tibial rotation and the tibia

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A lacrosse player carrying the ball attempts to avoid a defender by planting his right foot fi rmly on the ground and cutting hard to his left. His knee imme-diately gives way, and he hears a loud pop. He has intense pain immediately, but after a few minutes he feels as if he can get up and walk.

? What ligament has most likely been injured? What stability tests should the athletic trainer do to determine the extent of the injury to this ligament?

FIGURE 2020 A, Pivot-shift test (Gallaway and McIntosh) for anterolateral rotary instability. The tibia is subluxated in extension. It reduces at 20 degrees of fl exion. B, Slocums knee test is exactly the same but done in a side-lying position.

A B

FIGURE 2021 Jerk test of Hughston for anterolateral rotary instability. The tibia is reduced in fl exion. It sub-luxates as the knee moves to 20 degrees of extension.

FIGURE 2022 A, Flexion-rotation drawer test. The leg is externally rotated and moved from extension to fl exion. B, Losees test is similar but is done with the patient side-lying.

A

B



Instrument Assessment of Cruciate Laxity Several ligament-testing devices called arthrometers are cur-rently available that objectively quantify the anterior or posterior displacement of the knee joint, thus reducing much of the subjectivity associated with the previously described tests. 89 The KT-2000 knee arthrometer, the Stryker knee laxity tester, and the Genucom are three such testing devices (Figure 2026).

Measurements taken postoperatively and at pe-riodic intervals throughout the rehabilitation pro-cess provide an objective indication to the athletic trainer about the effectiveness of the treatment program in maintaining or reducing anterior or posterior translation. 76

Meniscal Tests Determining a torn meniscus can be diffi cult. The three most commonly used tests are McMurrays meniscal test, the Apley compression test, and the Thessaly test.

McMurrays Meniscal Test McMurrays meniscal test (Figure 2027) is used to determine the presence of a displaceable meniscal tear within the knee. The ath-lete is positioned faceup on the table with the injured leg fully fl exed. The athletic trainer places one hand on the foot and one hand over the top of the knee, fi ngers touching the medial joint line. The ankle hand scribes a small circle and pulls the leg into extension. As this occurs, the hand on the knee feels for a click-ing response. Medial meniscal tears can be detected when the lower leg is externally rotated, and internal rotation allows the detection of lateral tears.

Apley Compression Test The Apley compression test (Figure 2028) is performed with the patient lying facedown and the affected leg fl exed to 90 degrees. While stabilizing the thigh, the athletic trainer ap-plies a hard, downward pressure to the leg and ro-tates the leg back and forth. If pain results, a meniscal injury has occurred. A medial meniscal tear is noted by external rotation, and a lateral meniscal tear is noted by internal rotation of the lower leg.

Thessalys Test In the Thessalys test, the patient stands fl atfooted on the fl oor (Figure 2029).42 The clinician stands in front of and supports the patient by holding

Posterior Drawer Test The posterior drawer test is performed with the knee fl exed at 90 degrees and the foot in neutral. Force is exerted in a posterior direction at the proximal tibial plateau. A positive posterior drawer test indicates damage to the poste-rior cruciate ligament (Figure 2023).

External Rotation Recurvatum Test The athletic trainer grasps the great toe and lifts the leg off the table. If the tibia externally rotates and slides posteri-orly, there may be injury to the posterior cruciate lig-ament and posterolateral corner of the joint capsule, creating posterolateral instability (Figure 2024). 76

Posterior Sag Test (Godfreys Test) With the patient supine, both knees are fl exed to 90 degrees. Observ-ing laterally on the injured side, the tibia will appear to sag posteriorly when compared with the opposite extremity if the posterior cruciate ligament is dam-aged (Figure 2025). 76

FIGURE 2023 Posterior drawer test.

FIGURE 2024 External rotation recurvatum test.

FIGURE 2025 Posterior sag test (Godfreys test).

FIGURE 2026 Knee arthrometer for measuring knee laxity objectively.



antigravity muscles and assist humans in maintain-ing an erect, straight-leg position. They are in con-stant use in effecting movement. Atrophy results when a lower limb is favored and is not used to its potential. Measurement of the circumfer-ence of both thighs can often detect former leg inju-ries or determine the extent of exercise rehabilitation. Five sites have been suggested for girth measure-ment: the joint line (tibial plateau), 8 to 10 cm above the tibial plateau; the level of the tibial tubercle; the belly of the gastrocnemius muscle measured in cen-timeters from the tibial tubercle; and 2 cm above the superior border of the patella recorded in centime-ters above the tibial tubercle (Figure 2030). 48

Because the musculature of the knee atrophies so readily after an injury, girth measurements must be taken routinely.

his or her outstretched hands. The patient then rotates his or her knee and body, internally and externally, three times, keeping the knee in 5 degrees of fl exion. This procedure is repeated with the knee fl exed at 20 degrees. In a positive test, the patient reports me-dial or lateral joint-line discomfort and may have a sense of locking or catching. With this maneuver, the knee with a meniscal tear is subjected to excessive loading conditions. The test is always performed fi rst on the normal knee, so that the patient can compare the Normal with the injured knee. 42

Girth Measurement A knee injury is almost always accompanied by an eventual decrease in the girth of the thigh musculature. The muscles most affected by disuse are the quadriceps group, which are

FIGURE 2028 Apley compression test.

FIGURE 2027 McMurrays meniscal test. A, The clinician fl exes the knee and laterally rotates the tibia, then B, extends the knee while palpating the medial joint line. Next, the clinician fl exes the knee and medially rotates the tibia, then extends the knee while palpating the lateral joint line.

A

B

FIGURE 2029 Thessalys test performed at both 5 degrees and 20 degrees of knee fl exion.

FIGURE 2030 Five sites for girth measurement.

1

2

3

4

5

1. 8 to 10 cm above joint line

2. 2 cm above patella

3. Joint line (tibial plateau)

4. Tibial tubercle

5. Belly of gastrocnemius



and single-leg hop test are also useful functional tests. If the patient can do a deep knee bend or duck walk without discomfort, it is doubtful that there is a meniscal tear. The resistive strength of the hamstring and quadriceps muscles should be compared with the strength of the uninjured knee (Figure 2031). The patient should be able to perform these tests at full speed, without limping or favoring the injured knee. If baseline testing was done prior to injury, the baseline results should be used to compare with postinjury test results to determine if the patient is able to perform at preinjury levels.

Patellar Examinations Any knee evaluation should include inspection of the patella. Numerous evaluation procedures are associated with the patella and its surroundings. The following evaluation procedures can provide valuable information about possible reasons for knee discomfort and problems in functioning. 83

Subjective Rating Scales On occasion, subjective rating scales, such as the Lysholm Knee Scoring Scale, the Cincinnati Knee Scale, the International Knee Documentation Committee (IKDC) Scale, and the Knee Outcome Survey, have been used to deter-mine the patients perception of how well the injured knee is doing relative to pain, stability, and functional performance. The information obtained from these rating scales can be combined with fi ndings from sta-bility testing to help with an initial diagnosis or eval-uation of progress in rehabilitation ( Focus Box 201: Lysholm knee scoring scale).

Functional Examination It is important that the patients knee also be tested for function. The patient must be able to bear weight prior to attempting functional testing. The patient should be observed walking and, if possible, run-ning, turning, performing fi gure eights, backing up, and stopping. The cocontraction test, vertical jump,

FOCUS 201 FOCUS ON EVALUATION AND DIAGNOSIS

Lysholm knee scoring scale

Please check the statement that best describes the 1. way you walk.

_____ I never walk with a limp. _____ I rarely walk with a limp or I walk with a slight

limp. _____ I walk with a constant and severe limp.

Which of the following do you presently use as a sup-2. port while you walk?

_____ I can walk without crutches or a cane. _____ I can put some weight on my leg, but I need at

least one crutch or a cane to walk. _____ I cannot put any weight on my leg when walking.

Do you experience LOCKING of your knee? 3. _____ No, never. _____ My knee catches, but does not lock. _____ Yes, my knee locks occasionally. _____ Yes, my knee locks frequently. _____ Yes, my knee is locked all the time.

Do you experience slipping or giving way of your knee? 4. _____ No, never. _____ Yes, rarely during sporting activities or other

severe exertion. _____ Yes, frequently during sporting activities or

other severe exertion. _____ Yes, occasionally during daily activities. _____ Yes, frequently during daily activities. _____ Yes, on every step.

Which of the following best describes your level of 5. pain?

_____ I have no pain in my knee. _____ I have occasional pain, which is slight and

present only after severe exertion.

_____ I have marked pain during severe exertion. _____ I have marked pain after walking more than

2 miles. _____ I have marked pain after walking less than

2 miles. _____ I have constant pain.

Which of the following best describes swelling in your 6. knee?

_____ I have no swelling. _____ I have swelling only after severe exertion. _____ I have swelling after ordinary exertion. _____ I have constant swelling.

Which of the following best describes your ability to 7. climb stairs?

_____ I have no problems on stairs. _____ I am only slightly impaired on stairs. _____ I can negotiate stairs, but only one at a time. _____ I cannot go up or down stairs.

Can you get into a full squat position? 8. _____ Yes, no problems. _____ No, but I am only slightly impaired. _____ No, I cannot squat with my knee past

90 degrees. _____ No, I cannot squat at all.

THANK YOU FOR TAKING TIME TO COMPLETE THIS QUESTIONNAIRE.

From Tegner Y, Lysholm J: Rating systems in the evaluation of knee ligament injuries, Clin Orthop 198:43, 1985.



males and 15 degrees for females. Q angles that ex-ceed 20 degrees are considered excessive and could lead to a pathological condition associated with im-proper patellar tracking in the femoral groove. 45

The A Angle The A angle measures the patellar orientation to the tibial tubercle. It is created by the intersection of a line that bisects the patella longitu-dinally and a line from the tibial tubercle to the apex of the inferior pole of the patella (Figure 2032B). 3 An A angle of 35 degrees or greater has been cor-related with patellofemoral pathomechanics that seem to result in constant patellofemoral pain. The A angle serves as a quantitative measure of patellar realignment after rehabilitative intervention.

Palpation of the Patella With the patients quadri-ceps muscle fully relaxed, the examiner palpates the patella for pain sites around its periphery and under its sides (Figure 2033).

Patellar Compression, Patellar Grinding, and Apprehension Tests With the knee held to create approximately 20 degrees of fl exion, the patella is compressed downward into the femoral groove; it is then moved forward and backward (Figure 2034). If the patient feels pain or if a grinding sound is heard during the patellar grind test, a pathological condition is probably present. With the knee still fl exed, the pa-tella is forced forward and is held in this position as the athlete extends the knee (Figure 2035). A posi-tive Clarks sign is present when the patient experi-ences pain and grinding. Another test that indicates whether the patella can easily be subluxated or dislo-cated is known as the patellar apprehension test (Fig-ure 2036). With the knee and patella in a relaxed position, the examiner pushes the patella laterally.

The Q Angle The Q angle is created when lines are drawn from the middle of the patella to the antero-

superior spine of the ilium and from the tubercle of the tibia through the cen-ter of the patella

(Figure 2032A). It should be measured with the knee fully extended and with the knee fl exed at 30 degrees. The normal Q angle is 10 degrees for

A Q angle greater than 20 degrees could predispose the athlete to patellar femoral pathology.

FIGURE 2031 A, Testing quadriceps strength. B, Testing hamstring strength.

A

B

FIGURE 2032 A, Measuring the Q angle of the knee. B, Determining the A angle.

Patella(center)

Tibialtubercle

A

Q

Anteriorsuperioriliac spine

Tibialtubercle

Inferiorpatellarpole

A

B



The patient will express sudden apprehension at the point at which the patella begins to dislocate. 67

PREVENTION OF KNEE INJURIES Preventing knee injuries in sports is a complex problem. Physical conditioning, rehabilitation and skill development, and shoe type are important fac-tors. The routine use of protective bracing may be a questionable practice.

Physical Conditioning and Rehabilitation To avoid knee injuries, an athlete should be well con-ditioned, which means total body conditioning that

includes strength, neu-romuscular control, fl exibility, cardiovas-cular and muscle en-durance, agility, speed, and balance. 68 Spe-cifi cally, the muscles surrounding the knee joint must be strong and fl exible. The joints and soft tissue that make up the kinetic chain of which the knee is a part must also be considered sources 2

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A police offi cer is six months postACL recon-struction. He has been cleared by the physician to return to duty. However, he still has a concern about his knee being reinjured. He wants to know whether he should be wearing a functional knee brace.

? What should the athletic trainer recommend to this offi cer?

of knee injury and therefore must be specifi cally con-ditioned for strength and fl exibility. 74 Athletes partici-pating in a particular sport should acquire a strength ratio between the quadriceps and hamstring muscle groups. For example, the hamstring muscles of foot-ball players should have 60 percent to 70 percent of the strength of the quadriceps muscles. 68 The gas-trocnemius muscle should also be strengthened to help stabilize the knee. Although maximizing muscle strength may prevent some injuries, it fails to prevent rotatory-type injuries.

Avoiding abnormal contraction of the muscles through fl exibility exercises is a necessary protec-tion for the knee. Gradual stretching of the knee musculature helps the muscle fi bers become more extensible and elastic. 68 Of special concern in pre-venting knee injuries is the extensibility of the hamstrings, erector spinae, groin, quadriceps, and gastrocnemius muscles.

Knees that have been injured must be prop-erly rehabilitated. Repeated minor injuries to a knee make it susceptible to a major injury. (See the section on knee joint rehabilitation later in this chapter.)

Describing the Risk of ACL Injury Even though the exact mechanisms of ACL in-jury have not been scientifi cally confi rmed and agreed upon, the numerous theories concerning

FIGURE 2033 Palpating the periphery of the patella while the quadriceps muscle is fully relaxed.

FIGURE 2035 Patellar grind test. While the knee is fl exed, the patella is forced forward; the patient then actively contracts the quadriceps. The test reveals a positive Clarks sign if the athlete feels pain or grinding.

FIGURE 2034 Patellar compression test. The patella is pressed downward in the femoral groove and moved forward and backward to elicit pain or crepitus.

FIGURE 2036 Patellar apprehension test for the easily subluxated or dislocated patella.



Functional and Prophylactic Knee Braces Functional and prophylactic knee braces are discussed in Chapter 7. These braces have been designed to pre-vent or reduce the severity of knee injuries. 95 Prophy-lactic knee braces are worn on the lateral surface of the knee to protect the medial collateral ligament. 95 Functional knee braces are used to protect grade 1 or 2 sprains of the ACL or, most commonly, a surgically reconstructed ACL. These braces are custom-molded and are designed to control rotational stress or tib-ial translation. The effectiveness of protective knee braces is controversial at best (Figure 2037). 25 It is generally accepted that they have little or no effect on functional performance measures. 25

RECOGNITION AND MANAGEMENT OF SPECIFIC INJURIESLigament Injuries The major ligaments of the knee can be torn in isolation or in combination. Depending on the ap-plication of forces, injury can occur from a direct straight-line or single-plane force, from a rotary force, or from a combination of the two. 5

Medial Collateral Ligament Sprain Etiology Most knee sprains affect the MCL from

either a direct blow from the lateral side in a medial direction (valgus force) or from lateral tibial rotation. Greater injury results from medial sprains than from lateral sprains because of their more direct relation to the articular capsule and the medial meniscus (Figure 2038). Medial and lateral sprains occur in varying degrees, depending on knee position, previ-ous injuries, the strength of the muscles crossing the joint, the force and angle of the trauma, fi xation of the foot, and the conditions of the playing surface.

The position of the knee is important in estab-lishing its vulnerability to traumatic sprains. Any

biomechanical and neuromuscular aspects of ACL injury have provided the foundation for limited success in the early development of ACL injury prevention programs. An intervention plan consist-ing of instructional training techniques (e.g., verbal cues, videotape, slides, and physical practice) has been shown to be effective in reducing ACL injuries in female collegiate athletes. 29 A proprioceptive bal-ance board training program performed during the preseason has been shown to signifi cantly reduce the incidence of ACL injuries in professional soccer athletes. 68 A study looking at the effect of neuro-muscular training on the incidence of serious knee injury in female athletes showed that untrained fe-male athletes had a 3.6 times higher incidence of knee injury as compared with the neuromuscular- trained female athletes. 25 A program involving a combination of weight training, landing instruc-tional cues, stretching, and plyometric training has been successfully used to infl uence jump-landing kinematics and kinetics in adolescent athletes. 84

An intervention program consisting of strength, balance, and technique training was designed to infl uence an athletes ability to jump and land properly, to potentially reduce acute and chronic noncontact lower-extremity injuries. 22 The prem-ise of this program is based on the following con-cepts: jump-landing occurring in all functions (e.g., running, pivoting, and jumping), prehabilitation or the intervention of establishing ability prior to in-jury occurrence, and a single-leg concept of athletic movement that states that most athletic tasks are performed during a single-leg stance. The jump-landing technique is the main focus of the train-ing program and is based on the use of verbal cues, observational modeling, videotape feedback, and physical practice. Four verbal cues are stressed dur-ing the program: soft knees (landing with knee fl exion to absorb impact forces), load hips (hip fl exion to aid in impact absorption), quiet sound (try not to make a sound when landing), and toe-to-heel (landing on forefoot and rolling into heel contact). 57,58

Shoe Type During recent years, athletes who participate in collision sports, such as football, have been using soccer-style shoes. The change from a few long, conical cleats to a large number of short (no lon-ger than inch [1.25 cm]), broad cleats has sig-nifi cantly reduced knee injuries in football. A shoe with more and shorter cleats is better because the foot does not become fi xed to the surface but still allows controlled running and cutting. On artifi -cial or synthetic fi elds, the shoes worn generally have no cleats and the sole is merely some type of tread design.

FIGURE 2037 Prophylactic knee brace. (Courtesy DonJoy)



There is little or no joint effusion. There may be some joint stiffness and point ten- derness just below the medial joint line. Even with minor stiffness, there is almost full passive and active range of motion.

Management Immediate care consists of RICE for at least twenty-four hours. After immediate care, the following procedures should be undertaken:

Crutches are used if the patient is unable to walk without a limp. Follow-up care may involve cryokinetics, includ- ing twenty minutes of ice pack treatment before exercise or a combination of cold and compres-sion or pulsed ultrasound. Therapeutic exercise is essential, starting with phase 1 of the knee joint rehabilitation procedures.

Isometrics and straight-leg exercises are impor-tant until the knee can be moved without pain. The patient then progresses to stationary bicycle riding or a high-speed isokinetic program. Exercises for regaining neuromuscular function should also be incorporated.

position of the knee, from full extension to full fl ex-ion, can result in injury if there is suffi cient force. Full extension tightens both lateral and medial liga-ments. Flexion affords a loss of stability to the lateral ligament but maintains stability in various portions of the medial capsular ligament. 35 Medial collateral ligament sprains result most often from adduction and internal rotation. The most prevalent mecha-nism of a lateral collateral ligamentous or capsular sprain is one in which the foot is everted and the knee is forced laterally into a varus position.

Torn menisci seldom happen as a result of an initial trauma; most occur after the collateral liga-ments have been stretched by repeated injury. The cumulative effects of several mild to moderate sprains leave the knee unstable and thus vulnerable to additional internal derangements. The strength of the muscles crossing the knee joint is important in helping the ligaments support the articulation. These muscles should be strengthened to minimize the possibility of injury. Athletes can help protect themselves from knee injuries by developing mus-cular strength through proper conditioning.

The force and angle of the trauma usually de-termine the extent of injury that takes place. Even after an athletic trainer witnesses the occurrence of a knee injury, it is diffi cult to predict the amount of tissue damage. The most revealing time for testing joint stability is immediately after injury before ef-fusion masks the extent of derangement. Grade 1 medial collateral ligament sprain A grade 1 MCL injury of the knee has the following charac-teristics (Figure 2039A):

A few ligamentous fi bers are torn and stretched. The joint is stable during valgus stress tests.

Medialcollateralligamenttear

Valgusforce

External rotation

FIGURE 2038 A valgus force with the tibia in external rotation injures the medial collateral and capsular ligaments, the medial meniscus, and sometimes the anterior cruciate ligament.

FIGURE 2039 Medial collateral ligament sprain. A, Grade 1. B, Grade 2. C, Grade 3.

A Medial view

B Medial view

C Medial view



Functional progression activities should be incorporated early in the rehabilitation program. The patient should be encouraged to use a hinged brace when he or she tries to return to running activities.

Conservative care of the grade 2 medial collat-eral ligament sprain has been successful. Studies show that there can be spontaneous ligament and capsular healing because other structures, such as the anterior cruciate ligament, also protect the knee against valgus and rotary movement. 40 Grade 3 medial collateral ligament sprain Grade 3 MCL sprain means a complete tear of the supporting liga-ments (Figure 2039C). Major symptoms and signs include

Complete loss of medial stability Minimum to moderate swelling Immediate, severe pain followed by a dull ache Loss of motion because of effusion and hamstring guarding A valgus stress test that reveals some joint opening in full extension and signifi cant opening at 30 degrees of fl exion

Isolated grade 3 sprains of the MCL occur most often when the mechanism of injury involves a direct valgus force with the foot fi xed and loaded. MCL tears resulting from rotation combined with valgus stress with the foot fi xed but not loaded vir-tually always result in ACL and occasionally PCL tears. Thus, testing must include evaluation of ACL and PCL integrity. 76

Management RICE should be used for at least seventy-two hours. Conservative nonoperative treatment is recommended for isolated grade 3 MCL sprains. The question of repair or nonopera-tive management of MCL tears with associated ACL

The patient is allowed to return to full participa-tion when the knee has regained normal strength, power, fl exibility, endurance, and neuromuscular control. Usually, a period of one to three weeks is necessary for recovery. When returning to activity, the patient may require tape or brace support for a short period. Grade 2 medial collateral ligament sprain Grade 2 MCL knee sprain indicates both microscopic and gross disruption of ligamentous fi bers (Figure 2039B). The only structures involved are the me-dial collateral ligament and the medial capsular ligament. A grade 2 sprain is characterized by the following:

A complete tear of the deep capsular ligament and a partial tear of the superfi cial layer of the medial collateral ligament or a partial tear of both area

chapter 20

Documents

management of knee injuries

knee joint rehabilitation

injured knee

assessment of knee injuries

recognition of knee

prevention of knee injuries

knee joint complex

functional knee anatomy