T he proximal humerus is a common anatomic location for the occurrence of sarcomas. Although various reconstruction options are available after intraarticular resection, surgeons most commonly use endoprosthetic implantation. The glenohumeral articulation is extremely complex, composed of several musculotendinous units that all function synergistically to produce the most mobile joint in the body. This complexity is extremely difficult to reproduce after endoprosthetic reconstruction. As a result, two problematic issues tend to arise—instability and poor active ROM. Both of these conspire to produce a lifetime of poor function postoperatively in a frequently young and active patient population. Several solutions to these issues have been proposed. Use of allograft-prosthetic composites, which facilitate repair of the rotator cuff to the allograft, provides a theoretical advantage of biological healing [1]. Suture of the rotator cuff tendons directly to various synthetic mesh materials, which are wrapped around the endoprosthesis, as has been reported in the current study, provides a solid and stable platform for which to repair the transected tendons [3]. In both of these situations, instability continues to be a problem in a subset of patients and functional ROM is rarely, if ever, obtained. A more recent development is the reverse shoulder prosthesis, which relies on the retained deltoid to allow for a more functional ROM. Despite some evidence that active ROM is improved, the evidence must be weighed against the risk of prosthetic loosening and subsequent need for revision [2]. It remains evident that a satisfactory solution still eludes us.