Posterolateral corner reconstruction: Indications and techniques

OVERVIEW

Chapter synopsis

Posterolateral corner (PLC) injuries are rare and usually part of a multiligament injury pattern. If left untreated, these injuries may result in chronic pain, instability, failure of cruciate ligament reconstruction grafts, and failure to return to work or sports. The authors’ preferred reconstruction technique utilizes a single Achilles tendon allograft to reconstruct the lateral collateral ligament (LCL), popliteofibular ligament (PFL), and popliteus tendon, as well as a lateral capsular shift. Outcome studies demonstrate excellent restoration of stability, improved patient-reported outcome measures, and low risk of revision.

Important points

Common mechanisms of injury are a varus-directed force, knee hyperextension, or an external rotation moment with the knee in flexion
Assessment of common peroneal nerve function and distal vascular status is imperative
Indications for PLC reconstruction include acute complete tears in the LCL, PFL, and popliteus tendon and chronic injuries with symptomatic instability

Clinical/surgical pearls

Identify and protect the common peroneal nerve throughout the procedure
Assess graft isometry prior to the creation of the LCL reconstruction tunnel by draping the graft over a Beath pin

Clinical/surgical pitfalls

Avoid creating the fibular tunnel too far laterally which could lead to “blow out” of the fibular head
Perform definitive fixation of the cruciate ligaments to restore the center of rotation, and the lateral side subsequently

Introduction

Posterolateral corner injuries are rare and often present as part of a multiligament injury pattern. If left untreated, posterolateral laxity can result in chronic pain, recurrent instability, and failure of cruciate ligament reconstructions. The posterolateral corner consists of three primary stabilizers: the lateral collateral ligament (LCL), popliteofibular ligament (PFL), and popliteus tendon. Diagnosis of these injuries can be challenging and is best performed using a combination of history, physical exam, plain radiographs, and advanced imaging. Standing hip to ankle radiographs are useful in the chronic setting as well to assess for varus alignment with lateral joint space widening for which osteotomy would be indicated. Reconstruction is typically recommended for acute mid-substance tears in the LCL, PFL, and popliteus tendon and for chronic posterolateral corner injuries. This chapter will present the authors’ preferred posterolateral corner reconstruction technique using a single Achilles tendon allograft and lateral capsular shift, describe key preoperative and postoperative considerations, and review clinical outcomes.

Preoperative considerations

History

A comprehensive history is essential when evaluating patients with a suspected posterolateral corner injury. Patients will commonly describe either a contact injury resulting in a varus-directed force, knee hyperextension, or an external rotation moment with the knee in flexion.

Typical history

Acute traumatic high energy injury
Sports injury
Ultra-low velocity injury in morbidly obese
Missed posterolateral corner injury in the setting of a failed anterior or posterior cruciate ligament reconstruction

Physical examination

Assessment of the overlying skin and soft tissues may reveal ecchymosis and swelling over the posterolateral knee. Since many posterolateral corner injuries result from knee dislocation, assessment of distal neurovascular status is imperative to identify common peroneal nerve and popliteal artery injury. If an arterial injury is suspected, the ankle-brachial index (ABI) should be calculated and compared to the contralateral side. Angiography can be performed as well depending on the clinical situation. The integrity of the cruciate ligaments should also be assessed.

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