KNEE DISLOCATION

EPIDIMOLOGY

• 0.2% of all orthopaedic injuries

• Usually NOT reported – Spontaneous reduction

• 14-44% associated with multiple trauma

• 5% bilateral

STABILIZERS OF KNEE JOINT• Static

• Joint Capsule• Collateral Ligaments• Medial Patellofemoral Ligament

• Dynamic• Quadriceps• Biceps Femoris• Pes Anserinus• Gastronemius• Tensor Fascia Lata• Semimembranosus• Popliteus

CLINCAL FEATURES

• May Present with irreducible dislocaton

• Deformity, pain ,cannot ambulate

• Spontaneously reduced- with only effusion

• Normal Knee ,BUT on examination shows instability

• Dislocation + Ipsilateral # lower extremity – Diagnostic

Challenge

• EUA following fracture stabilization

ASSOCIATED INJURIES• Vascular • Neurologic

IMAGING

A- PCL INTACT KNEE DISLOCATIONB- BICRUCIATE – Parallel arrangement of patella with femur

MRI • After reduction or suspected spontaneous reduction• To assess ligament status

CLINICAL FEATURES

KENNEDY CLASSIFICATION• Anterior • Posterior• Medial• Lateral• Rotatory

• Anteromedial• Anterolateral• Posteromedial• Posteolateral (MC ROTATORY)

POSTEROLATERAL• Hallmark – Irreducibility

• Medial femoral condyle buttonholes through the medial capsule and medial collareral ligament invaginates into knee joint preventing closed reduction

• TRANSVERSE FURROW in medial aspect of knee

Treatment Indications Advantages DisadvantagesEarly Open Repair (First

week)

Avulsions with

large bony

fragments

1.Secure fixation

2.Maintain native ligaments

1.Most injuries are either midsubstance

tears or are avulsions without bone and

repair is not possible

2.Wound healing problems due to soft

tissue envelope injury

3.Increased risk of stiffness

Acute (2-“4 weeks)

reconstruction of all

ligaments

Knee dislocation

with bicruciate

injury and no large

bony fragments

1.Early restoration of ligament

2.Fewer surgical procedures than staged

cruciate reconstruction

3.Allows early rehabilitation

Length of surgery

Acute (2-4 weeks)

reconstruction cruciates

staged with delayed (6

weeks) ACL

reconstruction

Knee dislocation

with bicruciate

injury and no large

bony fragments

1.Shorter initial procedure

2.Return to OR at 6 weeks allows

manipulation to increase motion

3.Allows early rehabilitation

1.Requires one additional surgery

2.Rehabilitation in the first 6 weeks as

in an ACL-deficient knee

Delayed (>1 month)

reconstruction after

motion is reestablished

and ipsilateral injuries

are healed

Knee dislocation

with soft tissue

injury

1.Establishes good motion prior to

surgery

2.Simultaneous bicruciate

reconstruction better tolerated

1.Delays full reconstruction

2.Delays functional recovery to job,

sports, etc.

3.More difficult to obtain stable knee

with chronic reconstruction

Early spanning external

fixator with removal at

6-8 weeks,

manipulation, and

reconstruction if

necessary after motion is

obtained

Knee dislocation in

poor rehabilitation

candidate

1.Avoids lengthy procedure with

significant complications until

rehabilitation potential is clarified

2.Fewer complications

1.Difficult to obtain functional result

equivalent to early reconstruction

2.Delayed recovery

3.Staged procedure that may require

additional surgeries

4.Risk of infection

COMPLICATIONS

Stifness

Most common

Early ROM

MUA in 6 weeks if Physio does not yield good results

THANK YOU