Periprosthetic femoral fractures around tumor endoprostheses treated with limited revision surgery combined with allograft: A case report.

RATIONALE: Old periprosthetic femoral fractures (OPFFs) around a tumor prosthesis of the knee present formidable problems for orthopedic oncologists; large bone defects and inappropriate biomechanics of the revision implant design can impair successful reconstruction. Limited literature is available on the reconstruction of OPFFs using revision combined with massive allograft following resection of a bone tumor around the knee joint. In this study, we present the first reported case in the English literature of a limited revision followed by several segmental allografts for the reconstruction of the knee joint.

PATIENT CONCERNS: This case involved a 45-year-old female who was treated for a malignant fibrous histiocytoma (MFH) of the knee joint with surgical excision of the lesion and replacement of the defect using endoprosthetic reconstruction when she was 25 years old. Her surgical history was remarkable for a left tumoral knee prosthesis implanted 20 years ago. Nine years before revision, the patient had fall damage; however, she was able to walk independently and with moderate pain. In the 9-year period, prosthesis malfunction caused progressive left lower extremity shortening and a persistent swelling pain in the left thigh.

DIAGNOSES: According to her clinical history, imaging results and physical examination, we confirmed the diagnosis of OPFFs potentially due to aseptic loosening and trauma injury.

INTERVENTIONS: In this study, we present the first case of OPFFs around a tumor endoprosthesis that was successfully treated using limited revision combined with a massive allograft.

OUTCOMES: At 80 months after revision surgery, the patient had made a sufficient recovery from her symptoms. The bone union was complete without tumor recurrence or implant failure.

LESSONS: We propose that if prosthesis fracture is detected, revision surgery should be attempted as early as possible, and for patients with OPFFs, the use of limited revision combined with massive allografts may be useful for safely and adequately reconstructing OPFFs around the knee joint. However, patients should be followed-up closely after surgical treatment because of the high risk of revision.