Endoprosthetic Reconstruction of the Proximal Humerus with an Inverse Tumor Prosthesis

Abstract

Reconstructing the proximal humerus after tumor removal is challenging due to muscle and bone loss. The current methods often result in poor shoulder function. This study assessed the long-term functional and oncological outcomes of using an inverse proximal humerus prosthesis in 46 patients with bone tumors. The results showed a mean range of motion of 62° in anteversion, 28° in retroversion, and 55° in abduction. Notably, 23 patients achieved over 90° of shoulder abduction, with an average of 140°. The median Musculoskeletal Tumor Society Score was 25. Complications included infection in two radiotherapy patients and single dislocations in seven patients. One patient with recurrent dislocations needed revision surgery. In conclusion, the use of the inverse proximal humerus prosthesis in bone tumor treatment yields excellent shoulder function and high patient satisfaction. This approach is especially beneficial for those with metastatic disease.

Keywords: bone tumors; inverse tumor prosthesis; metastases; proximal humerus.

Figure 1

Study flow chart.

Figure 2

(A) MRI showing a Ewing’s sarcoma in a 13-year-old patient, (B) intraoperatively after reconstruction with an inverse tumor prosthesis and an attachment tube, (C) the 7-year follow-up X-ray shows, besides stress shielding, no signs of implant complications.

Figure 3

Range of motion in degrees. (MD—metastatic disease, PMT—primary malignant tumor, BR—bony resection, BSR—bone and soft tissue resection, RT—radiotherapy, NRT—no radiotherapy).

Figure 4

Active range of motion 5 years post-operation of a patient that was treated with Ewing’s sarcoma at the age of 13: neck grip, 180° abduction and anteversion.