Copyright © 2019 by National Association of Orthopaedic Nurses. Unauthorized reproduction of this article is prohibited.

© 2019 by National Association of Orthopaedic Nurses Orthopaedic Nursing • January/February 2019 • Volume 38 • Number 1 57

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Introduction One of the major stabilizing ligaments of the knee, the anterior cruciate ligament (ACL) primarily functions to control anterior translation of the tibia as well as pro-vides stabilization for rotational forces and, to a lesser degree, varus and valgus stress. Consisting of two domi-nant bundles, an anteromedial and a posterolateral, the ACL originates on the medial aspect of the lateral femo-ral condyle and inserts onto the tibial plateau, approxi-mately 15 mm posterior to the anterior articular surface ( Friedberg, 2018 ).

The annual incidence of ACL tears is estimated at one in 3,500, although, given lack of a standard mecha-nism for reporting these injuries within the general pop-ulation, it is likely higher. Surgical reconstruction of ACL tears accounts for up to 200,000 procedures annu-ally in the United States ( Friedberg, 2018 ).

The National Collegiate Athletic Association Injury Surveillance System has tracked information on ath-letes participating in 15 major collegiate sports since 1988. Here, we fi nd tears associated with football, which account for the highest reported rates of ACL tears, are typically from contact. Across all major sports, young female athletes have a higher incident of ACL tears than their male counterparts. Outside of football, the most commonly described injury, known as a pivot shift in-jury, is a noncontact incident involving a rapid decelera-tion on a planted foot with a rotational or valgus force applied to the knee ( Agel, Rockwood, & Klossner, 2016 ; Boden, Dean, Feagin, & Garrett, 2000 ; Friedberg, 2018 ; Mountcastle, Posner, Kragh, & Taylor, 2007 ; Prodromos, Han, Rogowski, Joyce, & Shi, 2007 ).

Case Presentation A 38-year-old man presented with a 2-day history of right knee pain, swelling, and feelings of instability after sustaining a fall. He slipped on the last couple of steps of a marble staircase, lunging forward and landing on the right foot. He described a forceful pivot shift-type injury, as the rest of his body “tumbled over” the planted right foot, ultimately landed onto his buttock. He had consid-erable pain at that time, requiring assistance to get up from the fl oor. He was able to “limp away” and noted signifi cant knee swelling within minutes of the injury occurring. A friend took him home, and he spent re-mainder of the day resting, icing, and elevating the leg. He took a couple of doses of ibuprofen, which helped the aching pain. He had a knee brace from a previous

Tear of the Anterior Cruciate Ligament Patrick Graham

Patrick Graham, MSN, RN, ANP-BC, Advanced Practice Provider and Advanced Practice Nurse, Northwestern Medical Faculty Foundation, Chicago, IL .

The author and planners have disclosed no confl icts of interest, fi nancial or otherwise .

DOI: 10.1097/NOR.0000000000000536

injury and wore that when up and about, noting the knee felt unstable otherwise. When things had not improved after another day, he presented for evaluation.

Upon presentation was an alert, oriented, affected-appropriate male in no apparent distress. He ambulated with a signifi cantly antalgic, straight-legged gait on the right. He was wearing a knee brace but was not using any other assistive device. There was a moderate effusion and mild warmth. No deformity, discoloration, or abrasions were present. Vague tenderness about the medial and pos-terior knee was noted. Range of motion was 0 ° –110 ° , with painful end-range fl exion. There was noted laxity with an-terior drawer and Lachman’s test. Pivot shift, bounce home, and McMurray’s tests were all positive. His strength was 5/5 and found to be distally neurovascularly intact.

Imaging obtained at the time of evaluation included anteroposterior, lateral, and oblique radiographs of the right knee (see Figure 1 ). These images were unre-markable. Given fi ndings of physical examination, most concerning a tear of the ACL, the patient was recommended to have magnetic resonance imaging (MRI) of the knee. He agreed, and fi ndings confi rmed the suspected clinical diagnosis of ACL tear (see Figure 2 ). Other fi ndings of the MRI, including bone marrow edema, joint effusion, generalized muscle strains, and a small meniscus tear, were consistent with the reported pivot shift injury.

Management Initial management includes rest, ice, compression, ele-vation, use of nonsteroidal anti-infl ammatory drugs, brace wear, and potential need for crutches with pro-tected weight-bearing, given the patient’s pain level and ambulatory status. Although ACL tears can be managed conservatively, most young, active, and athletic individu-als opt for surgical reconstruction in order to return to higher level activities such as sports. Graft selection and postoperative rehabilitation programs vary by provider and continue to be a source of debate in the literature. There is, however, suffi cient evidence to support a pa-tient’s choice to delay surgery if he or she wishes to

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58 Orthopaedic Nursing • January/February 2019 • Volume 38 • Number 1 © 2019 by National Association of Orthopaedic Nurses

undergo attempted rehabilitation before proceeding with surgery, as the difference in 5-year outcomes has no statis-tical signifi cance ( Friedberg, 2018 ; Frobell et al., 2013 ).

Those opting for conservative management are typi-cally low demand, such as older adults whose primary physical activity is community ambulation. Younger pa-tients who elect for conservative management should be aware of the risk of further joint damage, primarily me-niscal tears, which may result from joint instability. These patients also have signifi cantly lower return-to-sports rates as those who elect for surgery ( Friedberg, 2018 ; Frobell et al., 2013 ).

Referral to physical therapy, and patient compliance with the prescribed therapy treatments, is paramount in achieving optimal outcomes and returning patients to their previous level of function. Therapy regimens will vary but generally focus on quadriceps and hamstring strengthening, dynamic stabilization, gait training, and injury prevention. For those who intend to return to rig-orous sports, or strenuous physical activity in general, an ACL-stabilizing brace may be appropriate. Return to

sports should be done in a gradual fashion and only after the patient has achieved equal range of motion, strength, and stabilization within physical therapy ( Friedberg, 2018 ; Frobell et al., 2013 ).

Discussion An ACL tear should be primary on the list of differential diagnoses for any patient presenting with a pivot shift-type injury, especially if complaining of continued knee instability. This is confi rmed by testing joint laxity on physical examination. The advanced practice provider should be aware that Lachman’s testing is more sensi-tive than the anterior drawer test. If positive, the ad-vanced practice provider should perform MRI for con-fi rmation and potential surgical planning ( Friedberg, 2018 ; Frobell et al., 2013 ).

At minimum, patients should have initial conserva-tive management, followed by a course of physical ther-apy. Younger patients, which include most athletes, should be referred to an orthopaedic sports medicine

FIGURE 1. Anteroposterior, lateral, and oblique radiographs of the right knee. There is no evident fracture, dislocation, loose body, or signifi cant joint space narrowing noted on these images.

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© 2019 by National Association of Orthopaedic Nurses Orthopaedic Nursing • January/February 2019 • Volume 38 • Number 1 59

FIGURE 2. Sagittal T2 fat-suppressed and T1-weighted images, respectively—Ellipse denotes tear of anterior cruciate ligament. Note the “celery stalk” like appearance of this ligament, extending inferiorly-anteriorly from the 8 o’clock position on ellipse, which is evidence of underlying degeneration. There is also patchy bone marrow edema of the tibia and joint effusion that is better ap-preciated on the T2-weighted images .

surgeon for consultation regarding surgical options. Important conversations about the timing of surgery, graft selection, rehabilitation, and return-to-sports pro-grams should be done at the outset of treatment so that expectations better align with patient outcomes ( Friedberg, 2018 ; Frobell et al., 2013 ).

REFERENCES Agel , J. , Rockwood , T. , & Klossner , D. ( 2016 ). Collegiate

ACL injury rates across 15 sports: National Collegiate Athletic Association Injury Surveillance System data update (2004–2005 through 2012–2013) . Clinical Journal of Sport Medicine , 26 ( 6 ), 518 – 523 .

Boden , B. P. , Dean , G. S. , Feagin , J. A., Jr. , & Garrett , W. E., Jr . ( 2000 ). Mechanisms of anterior cruciate ligament injury . Orthopedics , 23 ( 6 ), 573 – 578 .

Friedberg , R. P. ( 2018 ). Anterior cruciate ligament injury . UpToDate. Retrieved from https://www.uptodate.com/

contents/anterior-cruciate-ligament-injury?search = acl%20tear&source = search_result&selectedTitle = 1 ∼ 36&usage_type = default&display_rank = 1#H19

Frobell , R. B. , Roos , H. P. , Roos , E. M. , Roemer , F. W. , Ranstam , J. , & Lohmander , L. S. ( 2013 ). Treatment of acute anterior cruciate ligament tear: Five year out-come of randomized trial . British Journal of Sports Medicine , 49 ( 10 ), 700 – 707 .

Mountcastle , S. B. , Posner , M. , Kragh , J. F., Jr. , & Taylor , D. C. ( 2007 ). Gender differences in anterior cruciate liga-ment injury vary with activity: Epidemiology of ante-rior cruciate ligament injuries in a young, athletic population . The American Journal of Sports Medicine , 35 ( 10 ), 1635 – 1642 .

Prodromos , C. C. , Han , Y. , Rogowski , J. , Joyce , B. , & Shi , K. ( 2007 ). A meta-analysis of the incident of anterior cruciate ligament tears as a function of gender, sport, and a knee injury-reduction regimen . Arthroscopy , 23 ( 12 ), 1320 – 1325 .

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