Posterolateral Approach to the Femur

What it exposes. The posterolateral approach gives extensile access to the femoral shaft from the greater trochanter to the lateral femoral condyle. Working the interval immediately behind the vastus lateralis and anterior to the lateral intermuscular septum delivers subperiosteal control of the linea aspera and the posterior, lateral and medial cortices through a single incision. Primary indications - Femoral shaft fractures requiring plate fixation — transverse, short oblique, or comminuted patterns unsuitable for intramedullary nailing.

• Femoral nonunion or malunion requiring open reduction, bone grafting and plate stabilisation.
• Infected nonunion requiring debridement, sequestrectomy and local antibiotic delivery.
• Tumour resection or biopsy of femoral shaft lesions.
• Revision surgery after failed intramedullary nailing when nail removal and exchange plating is planned. Why this approach is chosen. The linea aspera is the biomechanically ideal plate bed, and the exposure avoids the quadriceps mechanism anteriorly and the medial neurovascular bundle. It is extensile along almost the entire femur and can be combined with a separate anterolateral incision when dual plating or circumferential access is required. Contraindications (mostly relative) - Active infection in the surgical field (may still proceed for debridement).
• Severe soft-tissue loss or scarring that precludes closure.
• Inability to tolerate lateral or prone positioning (severe cardiopulmonary disease).
• Isolated anterior femoral lesions, which are better approached anterolaterally. Alternative approaches - Anterolateral approach — for proximal femoral fractures or when anterior plating is planned.
• Direct lateral approach — limited exposure, insufficient for long-plate constructs.
• Medial approach — rarely used; risks the femoral artery and vein.
• Posterior (Kocher–Langenbeck) approach — for acetabular or proximal pathology, not the shaft. Position & landmarks. Position the patient in lateral decubitus (affected side up) on a radiolucent table with full AP and lateral fluoroscopic access, or prone on chest rolls when bilateral posterior work is planned. Pad every pressure point (greater trochanter, fibular head, malleoli, axilla) and support the upper arm with the lower arm well padded. Slightly extend the affected hip and flex the knee 30–40 degrees to relax the sciatic nerve. Prep from the iliac crest proximally to the knee distally so the incision can extend in either direction. The palpable landmarks are the greater trochanter (proximal extent), the lateral femoral condyle (distal extent) and Gerdy's tubercle for distal orientation; the linea aspera is not directly palpable but corresponds to the posterior midline of the thigh. Soft-tissue guides are the iliotibial tract (a tight band along the lateral thigh with the knee extended), the biceps femoris tendon (posterior at the knee) and the vastus lateralis belly (anterior limit of dissection). Plan a 15–25 cm longitudinal incision along the posterior border of the iliotibial tract, centred over the pathology, allowing three to four screw holes proximal and distal to the fracture.

Work down through the layers along the posterior border of the iliotibial tract, develop the plane behind the vastus lateralis, divide the lateral intermuscular septum, ligate each perforator in continuity, and reach the linea aspera subperiosteally.

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Anatomy that governs the exposure - Bone: the femoral shaft is triangular in cross-section in the middle third, with the linea aspera forming the posterior apex. The shaft bows anteriorly with an average anterior bow of 10–15 degrees, and the nutrient foramen lies near the linea aspera in the middle third, entering from posterior.

• Muscle: the vastus lateralis arises from the linea aspera and the lateral intermuscular septum and is the only quadriceps muscle encountered. The lateral intermuscular septum separates the anterior compartment (vastus lateralis) from the posterior compartment (short head of biceps femoris and adductor magnus).
• Vessels: the perforating arteries (six to eight) arise from the profunda femoris, pierce the adductor magnus and the lateral intermuscular septum, and supply the vastus lateralis — each must be ligated.
• Nerve: the sciatic nerve lies in the posterior compartment, medial to the linea aspera in the proximal third, at risk during medial retraction; the femoral artery lies anteromedially and is shielded by the vastus medialis unless dissection is carried aggressively medial.

Structures at risk, by layer

Intra-operative complications

Post-operative complications

Sciatic nerve injury management - If the nerve is found transected intra-operatively, perform a primary repair; if neurapraxia is suspected, document and refer.

• For post-operative foot drop, obtain urgent EMG/NCS at 3 weeks and consider exploration if there is no recovery by 3–6 months.
• The reconstructive option for permanent foot drop is a tibialis posterior transfer to the dorsum of the foot. Extensile options - Proximal extension — carry the incision along the posterior border of the greater trochanter, split or retract the gluteus maximus in line with its fibres, and identify the sciatic nerve medial to the proximal femur to reach the piriformis fossa and subtrochanteric region. Watch for the superior gluteal vessels and the sciatic nerve.
• Distal extension — run the incision along the lateral femoral condyle, anterior to the biceps femoris tendon, open the iliotibial tract and reflect the vastus lateralis anteriorly; the knee capsule can be opened for intra-articular extension, protecting the lateral collateral ligament and popliteus posteriorly.
• Circumferential exposure — continuing subperiosteal elevation medially exposes the medial cortex and permits dual plating (lateral with posterior or medial) through the same incision.
• Combined approaches — pair the posterolateral with an anterolateral approach (through a separate incision) for dual plating of comminuted fractures, or with a medial approach for complex nonunion with bone loss; staged repositioning (lateral then supine) may be required. Closure & post-operative care - The lateral intermuscular septum needs no formal closure; close the fascia lata (iliotibial tract) with interrupted or continuous absorbable suture, let the vastus lateralis fall back, and close subcutaneous tissue and skin over a drain if dissection was extensive.
• Confirm reduction and fixation with AP and lateral radiographs of the entire femur.
• Neurovascular checks documenting sciatic function (dorsiflexion, plantarflexion, sensation) every 2 hours for the first 24 hours, with limb elevation and DVT prophylaxis (LMWH or aspirin per protocol, minimum 4–6 weeks).
• Weight bearing: non- or touch-weight-bearing for 6–12 weeks, progressing on radiographic healing to full weight bearing at 3–6 months for nonunion or comminuted fractures.
• Range of motion: early hip and knee ROM, aiming for full knee flexion and extension by 6–8 weeks, with quadriceps and hamstring strengthening once the wound has healed.
• Follow-up: 2 weeks (wound and suture/staple removal), 6 weeks, 3 months, 6 months (confirm union), and 1 year (final review).

• Femoral shaft plating — the principal operation: 4.5 mm broad or narrow DCP, LC-DCP or locking compression plate of adequate length, applied laterally (tension side) or posteriorly for buttress of posterior comminution, with cortical screws in compression diaphyseally and locking screws in poor-quality metaphyseal bone.
• Nonunion and malunion revision — debridement of the nonunion to bleeding bone, reduction, long-plate stabilisation with an adequate working length, and autograft (iliac crest or RIA from the contralateral femur) packed around the site; the exposure gives excellent posteromedial and posterolateral graft access.
• Infected nonunion — debridement, sequestrectomy and local antibiotic delivery with stabilisation.
• Tumour resection or biopsy of shaft lesions.
• Revision after failed intramedullary nailing — nail removal with exchange plating and grafting.
• Distal femur and Hoffa-type fractures — posterior-based plating and screw fixation through the distal extension.