knee dislocation

1. KNEE DISLOCATION

2. EPIDIMOLOGY
• 0.2% of all orthopaedic injuries
• Usually NOT reported – Spontaneous reduction
• 14-44% associated with multiple trauma
• 5% bilateral

3. STABILIZERS OF KNEE JOINT
• Static
• Joint Capsule
• Collateral Ligaments
• Medial Patellofemoral Ligament
• Dynamic
• Quadriceps
• Biceps Femoris
• Pes Anserinus
• Gastronemius
• Tensor Fascia Lata
• Semimembranosus
• Popliteus

5. 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

7. ASSOCIATED INJURIES
• Vascular
• Neurologic

10. IMAGING

12. A- PCL INTACT KNEE DISLOCATION
B- BICRUCIATE – Parallel arrangement of patella with femur

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

14. CLINICAL FEATURES

15. KENNEDY CLASSIFICATION
• Anterior
• Posterior
• Medial
• Lateral
• Rotatory
• Anteromedial
• Anterolateral
• Posteromedial
• Posteolateral (MC ROTATORY)

16. 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

25. Treatment Indications Advantages Disadvantages
Early 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

26. 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

27. COMPLICATIONS
Stifness
Most common
Early ROM
MUA in 6 weeks if Physio does not yield good results