Total Hip Arthroplasty on Unrecognized Bone Tumors: Dramatic Outcome from 11 Cases

Background: Several mistakes in the diagnosis and treatment of bone tumors can be made, especially in non-specialized centers. Implanting conventional prostheses on an unrecognized bone tumor causes contamination of the entire region with dramatic consequences for prognosis. Purpose of our study was to try to understand which is the best way to deal with these patients. Does previous surgery affect prognosis? Does external hemipelvectomy achieve a better overall survival and local control than limb salvage surgery? Hypothesis: Demolitive surgery, scarifying the involved limb ensures better local control of the disease and improves life expectancy. Patients and Methods: We retrospectively evaluated all patients with bone sarcomas at the site of a total hip arthroplasty (THA) over the years 2000-2012. After reviewing the preoperative imaging and histological slides, 11patients had a THA implanted on an unrecognized hip sarcoma. Diagnosis was chondrosarcoma in 10 patients and osteosarcoma in one. Five patients were immediately treated with external hemipelvectomy. Results: Five of 11 patients (45%) died of disease at a mean time of 34 months (range 2-82 months), 4 are alive with disease and only 2are continuously disease free. Six of eleven patients (55%) had a local recurrence at a mean time of 17 months (range 3-36 months); six of these patients had conservative treatment. Conclusions: Although a very rare event, failure to recognize an occult malignant bone tumor during total hip arthroplasty associates with poor survival rate. Outcome after limb saving surgery is disappointing due to a high rate of local recurrences. According to our experience external hemipelvectomy provides better local control but this condition remains a dramatic event.