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Knee Dislocation

Dr. Gajanan Pandit

Mumbai Port Trust Hospital

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Surgical anatomy

• It is a complex compound synovial joint• Superficial except posterior

• Knee stability - Osseous structures

Extraarticular structures, &

Intraarticular structures

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Osseous structures

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Extraarticular structures M

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Extraarticular structures L

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Extraarticular structures P

• popliteus muscle • arcuate ligament • prime medial rotator • withdraw L meniscus • rotary stability to

femur • preventing forward

dislocation + PCL

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Intraarticular structures

• Medial and Lateral Menisci

distribution of joint fluid, nutrition, shock absorption, deepening of the joint, stabilization of the joint, and a load bearing or weight bearing

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Intraarticular structures

• Cruciate ligaments

restrict the backward and forward motion of the tibia

assist control of both medial and lateral rotation

cruciate and collateral ligaments exercise basic antagonistic function during rotation

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Traumatic Dislocations

• Young adults, obese & athletic activities

• Relatively uncommon

• Spontaneous reduction • Diagnosis obvious except obese, polytrauma

• Devastating complications Poplitial artery ~20%

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Classification

• Open or closed

• velocity - high, low or ultra low

• Reducible or irreducible

• Position of the tibia (anterior, posterior, medial, lateral or rotary)

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Examination

• Deformity, pain, and swelling• Completion and documentation of a

thorough neurovascular examination are mandatory at initial evaluation, before reduction and after reduction

• Tests for ligamentous laxity attempted• Extensor mechanism • Compartment syndrome

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Radiographic Evaluation

• Anteroposterior, lateral and oblique views - direction of dislocation & bony injuries

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Radiographic Evaluation

• MRI

actual site cruciate and collateral ligament injury, meniscal disorders or injuries, and status of the popliteal tendon

• ACL-midsubstance tears (45%)> femoral avulsions (34%) > tibial avulsions (21%).

• PCL-femoral avulsion (76%)> midsubstance tear (17%)> tibial avulsion (7%).

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Sequence of Surgery for Traumatic Knee Dislocation

• Examination under anesthesia (EUA)  • Arthroscopic examination • Treatment of meniscal and osteochondral injuries  • Reconstruction of cruciate ligaments• Repair, augmentation, reconstruction of collateral

ligaments• ROM and EUA to ensure proper fixation • Radiographic confirmation

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Reconstruction of cruciate ligaments

• PCL tibial tunnel• PCL femoral tunnel• ACL tibial tunnel• ACL femoral tunnel

• PCL tibial tunnel• ACL tibial tunnel• ACL femoral tunnel• PCL femoral tunnel

Passage and fixation of PCL then ACL graft in femoral tunnel.

Tensioning and fixation of PCL graft with knee at 90 degrees of flexion & ACL in full extension.

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Rehabilitation