[Proximal tibial reconstruction with gastrocnemius flap].

OBJECTIVE

Technique for limb-salvage surgery of tumors of the proximal tibia. Endoprosthetic replacement of the tibia with a modular tumor endoprosthesis and reconstruction of the extensor mechanism with a gastrocnemius flap.

INDICATIONS

Primary tumors and recurrences of semimalignant tumors of the proximal tibia. Diagnosis by biopsy and, depending on the entity, neoadjuvant chemotherapy.

CONTRAINDICATIONS

Tumor infiltration of nerves or vessels, massive soft tissue infiltration, pathologic fracture, superinfection.

SURGICAL TECHNIQUE

The tumor is resected en bloc with wide margins including the biopsy scar, the knee joint is resected intra-extra articular, politeal structures are exposed (anatomical border to the tumor is the popliteus muscle), osteotomy of the tibia 3-5 cm distal of the tumor. After removing the tumor, reconstruction with a modular tumor endoprosthesis is performed. The medial gastrocnemius muscle is detached and mobilized, rotated anteriorly and connected to the patella tendon. Closure of the muscle and skin.

POSTOPERATIVE MANAGEMENT

Suction drainage for 48 h, extension brace for 2 weeks, followed by partial weight-bearing for 6 weeks.

RESULTS

Despite technical developments over the years, a complication rate > 10% remains. Secondary amputation due to local recurrence is reported in about 10% of cases and due to infection in 6-12%. Transient or permanent palsy of the peroneal nerve is observed in 5% of cases. A quarter of all patients have full (< 20° extension lag) active extension, the mean extension lag is about 30°. The probability of a revision (including implant related) is 60-70% after 10 years. Based on the clinical results, the technical demanding resection of the proximal tibia is a recommendable procedure.