PATELLA DISLOCATION

WAN AWATIF WAN MOHD ZOHDI

• Knee flexed, quadriceps relaxed >> patella forced laterally by direct force.:RARE

• Common: due to indirect force

MECHANISM OF INJURY

Sudden, severe contraction of quadriceps muscleWhile the knees is stretch in VALGUS & EXTERNAL

ROTATION

Lateral patellar dislocation. (a) Drawing shows the classic mechanism of injury: fixed tibia, internal femoral

rotation, and quadriceps contraction.

• Tearing sensation • Knee has gone ; out of joint• When running : they may collapse and fall to

the ground• Patella springs back into position

spontaneously• remains unreduced >>deformity

CLINICAL FEATURES

• Downward dislocation Stuck btw condylesMarked prominence on front of the knee• If spontaneous reduction:-swollen knee-bruising tenderness on medial side• Joint aspiration-blood stained-fat droplets (concurrent osteochondral #)

IMAGING

MRI

X-RAY

VIEW: AP, lateral

In unreduced dislocation: Patella is laterally displaced-tilted/rotated

X-RAY

Soft tissue lesion- disruption of medial patellofemoral ligament

MRI

MANAGEMENT

CONSERVATIVE

SURGICAL

CONSERVATIVE MX

Push back w/o difficulty & anesthesiaCast splintage;• If no sign of soft tissue lesion• Retained for 2-3 weeks• Quadriceps strengthening exercise ; 2-3

months• Jt aspiration and immobilized it in full

extension

SURGICAL MX

In intra articular (intercondylar) dislocation >> open reduction

If swelling, tenderness, bruising (medially)>> d/t patellofemoral ligaments torn, retinacular

t/s torn

• Recurrent dislocation• 1st time –treated as non-operatively• 15-20% recurrent dislocations.

COMPLICATION

TIBIAL PLATEAU FRACTURES

DEFINITION

• A tibial plateau fracture is a fracture involving the proximal (upper) portion of the tibia which extends through the articular surface .

• Caused by a varus/valgus force combined with axial loading

• Eg: car striking a pedestrian (bumper #)• Often: fall from a height in which the knee is

forced into valgus/varus• Tibial condyle is crushed/split by opposing

femoral condyle.• Combination of both the above

MECHANISM OF INJURY

• 60% lateral pleateau• 15% medial plateau• 25% bicondylar lesions.

TYPE 1:vertical split of the

lateral condyle

TYPE 2: vertical split of the lateral condyle +

depression of an adjacent loadbearing part of the

condyle

TYPE 3 : depression of the articular

surface with an intact condylar rim

TYPE 4 : # of the medial

tibial condyle

TYPE 5 : # of both condyles

TYPE 6 : combined condylar &

subcondylar #

PATHOLOGICAL ANATOMY

Schatzker classification

Type 1 •In younger people•Virtually undisplaced•Condylar fragment may be pushed inferiorly or tilted

Type 2 •Joint is widened•If # is not reduced : >> valgus deformity

Type 3 •Split to the edge of the plateau is absent•Stable joint•May tolerate early movement

Type 4 •2 types #•Low energy lesion : depressed, crush # of osteoporotic bone in elderly pt•High energy l/s : condylar spilt that runs obliquely

Type 5 •Column of metaphysis wedged in btw that remains in continuity with the tibial shaft

Type 6 •High energy injury•>>severe comminution•Tibial shaft disconnected from tibial condyles.

Clinical features

• Swollen knee• Deformed• Extensive bruising• Doughy tissue (d/t haemarthrosis)• Medial/lateral instability• Examined leg/foot carefully TRO

neuro/vascular injury

Imaging

• X-ray View : AP, Lateral , oblique• CT : amount of comminuted and depression #• Give information on the location of the main #

lines, site and size portion of condyle that is depressed

• Crushed lateral condyle, >>medial ligament is intact

• Crushed medial condyle >> lateral ligament may be torn

ManagementTYPE 1 #

Undisplaced

• Conservatively• Haemarthrosis is aspirated• Apply compression bandage• Limb is rest on CPM machine• Acute pain and swelling is subsided >> hinged cast-brace• Weight bearing –delayed ` 8 weeks

Displaced

• Open reduction• Internal fixation

TYPE 2 #

Slight depression(<5mm), stable knee, old patient,

osteoporotic pt•# is treated closed to gain mobility and fx ( not anatomical restitution)•Aspiration•Compression bandage•Skeletal traction via threaded pin.•Active exercises every day•# -sticky in 3-4 weeks >> remove traction pin•Apply hinge cast brace•Full weight bearing deferred ; 6 weeks

Depression >5mm

•Open reduction with elevation of plateau•Internal fixation•Small 3.5 mm screws // beneath the subchondral bone hold up elevated fragments : raft screws•Buttress plate :-in type 2,,5 or 6

TYPE 3 #

• Similar to type 2• But lateral rim of the condyle is INTACT• Stable knee• Depressed fragments :elevated through a

window in the metaphysis• Elevated fragements :supported by bone

graft , raft screws.• Post op :exercises, cast –brace till # is united.

TYPE 4 #

• Osteoporotic # crush –difficult to be reduced• >> varus deformity• Principles mx similar in type 2 #• Medial condylar split # : d/t high energy

impact.• Underlying lateral ligament injury

Assess ligament injury

If unstable joint after the fixation

Repair the torn structure on the lateral side.

TYPE 5 and 6 #

• Risk to compartment syndrome• In a simple condylar # and in an elderly pt:-reduced by traction-treated as type 2 injury• Usually internal fixation, early joint movement.• Danger of wide exposure to access both condyles:-increase wound breakdown-delayed or non-union

COMPLICATTIONS

LATE

JOINT STIFFNESS

DEFORMITY

OSTEOARTHRITIS

EARLY

COMPARTMENT SYNDROME

FRATURES OF TIBIA AND FIBULA

Mechanism of injury

• Twisting force >> spiral # of both bones at different levels• Angulatory force >> transverse, short oblique #, at the

same level• Indirect injury :-low energy-spiral or long oblique # , one of the bone fragments may

pierce the skin• Direct injury:-crushes/splits skin over the #Common in motorcycle accident

Pathological anatomy

• Behaviour of these injuries will depends on mode of treatment

• It depends on following factors:

State of soft tissues

Risk and CX depends on amount and type of

soft tissue damage

open# : Gustilo classification

closed # : Tscherne’s

Severity of bone injury

LOW ENERGY :-closed #

-Gustilo 1, 2 - spiral

HIGH ENERGY:-direct trauma

-open #-Gustilo 3

-transverse-comminuted

Stability of #

Consider displacement when weight bearing

is allowed

Sevely comminuted : least stable, need

mechanical fixation

IC1 •No skin lesion

IC2 •No skin laceration but contusion

IC3 •Circumscribed degloving

IC4 •Extensive, closed degloving

IC5 •Necrosis from contusion

TSCHERNE’s classification of skin lesions in CLOSED #

Clinical features

Examine limbs for signs of soft tissue damage• severe swelling, • bruising, • crushing or tenting of skin,• open wound, • circulatory changes, • weak or absent pulses, • loss of sensation, • Inability to move toes• Deformity

Alert for the compartment syndrome!!!!

Imaging

• X-ray of entire length of the tibia and fibula.(knee and ankle joints can be seen)

• Notes the :-types of #-level-angulation and displacement

MANAGEMENT

Limit soft t/s damage

Prevent/recognize compartment

syndrome

Obtain & hold the #

alignment

Start early weightbearing

Start joint movements

ASAP

LOW ENERGY #

• Gustilo type 1.• Conservative mx

LOW ENERGY #

Full length cast fr upper thigh to metatarsal necks

Knee is slightly flexed, ankle at a right angle

UNDISPLACED/

MINIMALLY DISPLACED

Reduced under GA with X-ray control

Alignment and rotation must be perfect

Full length cast.Position checked by x-ray

Limb is elevated, observe for 48-72 hours.

Discharged home on 2/3 rd day. With crutches

DISPLACED

EXERCISE

FUNCTIONAL

BRACING

SKELETAL FIXATION

CLOSED INTRAMEDULLARY NAILING

PLATE FIXATION

EXTERNAL FIXATION

HIGH ENERGY #

Transverse # • Usually stable after reduction• Treated as closed• Look for signs and symptoms of cx (excessive

pain, swelling, tightness, sensory change)Comminuted and segmental #• If a/w bone loss, unstable >> treat with early

surgical stabilization.

Closed #• External fixation• Closed nailing

Open #• Antibiotics• Debridement• Stabilization• rehabilitation

COMPLICATIONS

EARLY

VASCULAR INJURY

COMPARTMENT

SYNDROME

INFECTION

LATE

MALUNION

DELAYED UNION

NON-UNION

JOINT STIFFNESS

OSTEOPOROSIS