In limb salvage surgery for osteosarcoma of the distal femur, which of the following represents an absolute contraindication to limb-sparing resection?

• A Pathological fracture through the tumour before neoadjuvant chemotherapy
• B Soft-tissue extension abutting the popliteal vessels without encasement
• C Skip lesion in the ipsilateral proximal femur ✓
• D Tumour crossing the physis in a skeletally immature patient

Explanation

A skip lesion (a separate focus of osteosarcoma in the same bone or across a joint, without continuity) implies multifocal intraosseous spread and mandates amputation because a single en-bloc resection cannot achieve oncologically clear margins encompassing both lesions. Pathological fracture is a relative contraindication (may still attempt salvage after good neoadjuvant response if haematoma is contained). Physeal crossing changes reconstruction strategy but is not an absolute contraindication.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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