PLC : CHOOSE THE RIGHT CASE Dr. Amrish Kumar Jha Ms (Ortho) Visiting Consultant ILS Multispecialty Hospitals, Dumdum, Kolkata Visiting Consultant Medica Superspeciality Hospitals, Kolkata

INTRODUCTION 7-16% knee injury cases with added PLC injury Isolated PLC injury is very rare Usually combined with PCL > ACL injury Missed PLC injury is common cause of ACLR failure

Common Mechanisms Blow to anteromedial knee Varus blow to flexed knee Contact and noncontact hyperextension injuries Knee dislocation

Associated injuries Common peroneal nerve (15-29%) Vascular injury PCL injury ACL injury

ANATOMY

Classification Grade I (0-5mm of lateral opening and minimal ligament disruption) Grade II (5-10mm of lateral opening and moderate ligament disruption) Grade III (>10mm of lateral opening and severe ligament disruption and no endpoint)

Symptoms Instability symptoms when knee is in full extension Physical exam Gait exam varus thrust or hyperextension thrust

Tests for PCL integrity Sag Sign Posterior Drawer Test Quadriceps Active Test

Varus stress Varus laxity at 0° indicates both LCL & cruciate (ACL or PCL) injury Varus laxity at 30° indicates LCL injury

Dial test > 10° external rotation asymmetry at 30° only consistent with isolated PLC injury > 10° external rotation asymmetry at 30° & 90° consistent with PLC and PCL injury

External Rotation Recurvatum Positive when lower leg falls into external rotation and recurvatum when leg suspended by toes in supine patient from 10 degree.

Reverse Pivot Shift Test Knee positioned at 90° and external rotation and valgus force applied to tibia as the knee is extended the tibia reduces with a palpable clunk – tibia reduces from a posterior subluxed position at ~20° of flexion to a reduced position in full extension (reduction force from IT band transitioning from a flexor to an extensor of the knee)

Peroneal Nerve Injury Altered sensation to dorsum of foot and weak ankle dorsiflexion approximately 25% of patients have peroneal nerve dysfunction

Radiographs Avulsion fracture of the fibula (arcuate fracture ) or femoral condyle Stress radiography can be done

MRI: CAN’T ASSESS DEGREE OF INSTABILITY 100% accurate for PCL Less accurate for PLC In acute injury may see bone bruising of medial femoral condyle and medial tibial plateau.

TREATMENT PROTOCOL

Nonoperative Indications – In isolated PLC Grade I or II injuries – Immobilize knee in full extension with protected weight bearing for ~3 weeks – Progressive functional rehabilitation focusing on quad strengthening with return to sports in 8 weeks

PRINCIPLES OF SURGERY

PLC repair Indications o only in isolated PLC injuries with bony or soft tissue avulsion o Able to operate within 3 weeks of injury

PLC reconstruction Indications – Most grade III isolated injuries – When repair not possible or has poor tissue quality

PLC repair/reconstruction, ACL and/or PCL reconstruction, +/- HTO indications – In acute and chronic combined ligament injuries HIGH TIBIAL OSTEOTOMY – in patients with varus mechanical alignment – failure to correct bony alignment jeopardizes ACL and PLC reconstruction success