Rapid-prototype endoprosthesis for palliative reconstruction of an upper extremity after resection of bone metastasis

To present a rapid-prototype (RP) endoprosthesis replacement after tumor resection in patients with bone metastasis of the upper extremity. The short-term complications and functional outcomes were evaluated as well as the survival of patients and endoprosthesis.

Bone metastasis patients who required bone resection and endoprosthesis replacement were enrolled and consented before operation. Custom-made endoprosthesis was fabricated from polymethyl methacrylate assisted by RP technology. After surgery was performed, patients were followed up daily until discharge and monthly until 6 months postoperatively for immediate post-operative complications and for signs of endoprosthesis failure. The functional outcome was evaluated 6 months postoperatively by the Musculoskeletal Tumor Society score (MTSS) and the Mankin score. Thereafter, patients' survival and arm condition were monitored every 3 months.

Sixteen cases participated on this study. There were nine proximal-, four total- and two distal humerus, and one proximal ulna replacement. The median follow-up period was 486 days. The mean MTSS was 55 % and the Mankin score was good in 64 % and fair in 36 % of the patients. Glenohumeral subluxation was observed in 23 % of the patients; however, a stable shoulder was achieved in all cases. There were no prosthesis failure or systemic breakage.

An RP endoprosthesis may have significant advantages when the entire humerus needs to be replaced, or periarticular sites are involved. This technique offers custom-made endoprosthesis with enough durability, and in a relatively short production time at reasonable costs which are suitable for palliative reconstruction.