Abstract
INTRODUCTION: The "Whoops Procedure" first described by Giuliano and Eilber in 1985 refers to an unplanned sarcoma resection, where a lesion presumed to be benign is inadvertently excised, only to later be diagnosed as malignant. This leads to higher risks of local recurrence, lower limb salvage rates, and poor functional outcomes. Osteosarcoma, the most common primary bone cancer in adolescents, requires meticulous pre-operative evaluation to prevent inadvertent contamination and ensure optimal treatment. CASE REPORT: We present a case of a 13-year-old girl who initially underwent curettage and intramedullary nailing for a suspected aneurysmal bone cyst of the proximal femur. Post-operative wound complications and persistent discharge prompted further evaluation, revealing a diagnosis of osteosarcoma. Due to medullary contamination from the prior surgery, limb salvage was not feasible, necessitating a total femur replacement with a modular prosthesis following perioperative chemotherapy. The procedure involved meticulous dissection, preservation of neurovascular structures, and reconstruction using customized titanium alloy prosthesis. The patient had an uneventful recovery with early mobilization and rehabilitation. DISCUSSION: Total femur replacement is a rare but necessary procedure in cases of extensive tumor involvement, especially after inadvertent contamination. Proper pre-operative planning, including imaging and biopsy by an experienced surgeon, is critical to avoid such complications. Advances in prosthetic design, including modular implants and enhanced fixation techniques, have improved functional outcomes. A multidisciplinary approach involving oncologists, orthopedic surgeons, and pathologists is essential for optimal management. CONCLUSION: This case highlights the critical role of early biopsy and specialized care in bone tumor management. The "Whoops Procedure" should be avoided through thorough pre-operative assessment. When faced with extensive contamination, total femur replacement remains a viable solution, offering good functional outcomes with proper surgical planning and rehabilitation.