Proximal humerus allograft prosthetic composites: technique, outcomes, and pearls and pitfalls

Abstract

The proximal humerus is the second most common location of primary bone sarcomas and a frequent location of benign locally aggressive primary osseous tumors. In contrast to other locations, tumors in this region impose significant challenges for local control and reconstruction. This is due to glenohumeral joint anatomic characteristics such as lack of intrinsic stability and dependence on dynamic and static stabilizers. In addition, the close proximity of the axillary nerve and axillary vascular bundle places these at risk of resection when attaining local control. Allograft prosthetic composites (APCs) of the proximal humerus are one of the methods for mobile reconstruction. This modality presents lower fracture rates when compared to osteoarticular allografts and lower rates of subluxation and instability than endoprosthesis. Recent literature documents a trend for superior functional outcome at comparable complication rates. APC reconstruction is an important tool in the orthopedic oncologist armamentarium.

Complications and Survivorship of Distal Humeral Allograft Reconstruction After Tumor Resection: Literature Review and Case Series

“…Furthermore, several studies have shown allograft fracture, and not infection, to be the most common cause of failure and revision surgery in proximal humerus allograft reconstruction. 31 , 32 It is also important to note that fractures were the most common reason for revision surgery in our case series but were not found in the published literature. It is commonly thought that fractures are the number one reason for failure and subsequent revision surgery in allograft reconstructions, but this study shows that it is also important to assess nonunion and joint instability risk factors as well to prevent complications.…”

“…The second-most frequent complication is allograft fracture, which is a consistently prevalent event in allograft reconstruction of the proximal humerus in addition to subluxation. 32 Other complications from allograft reconstruction of the distal humerus include nerve injury and infections. Contrary to the common perception of the high risk of infection in this location because of soft-tissue coverage challenges, infection was not relevant.…”

Proximal Humerus Reconstruction after Tumor Resection: An Overview of Surgical Management

“…The association of allografts with prostheses theoretically allows matching the structural advantages from both reconstructions. Allograft's possibility to anchor surrounding soft tissues and therefore increase articular stability is combined with prostheses' durability; a more rigid construct is created and lower risk of fractures, subchondral collapses, and dislocations are achieved [ 128 ].…”

“…After an intraarticular 1A resection of proximal humerus, an allograft-reverse prosthesis composite should be taken into consideration, remembering that this reconstruction requires good bone stock on the glenoid, integrity of the axillary nerve, and preserved deltoid function to guarantee satisfactory functional outcomes [ 128 ]. Surgical procedure assumes the use of an appositely prepared frozen allograft to replace proximal humerus and accommodate the prosthetic stem; the proximal part of the prosthesis is cemented to the graft and the distal stem is inserted in the native bone canal, either cemented or press-fitted.…”

Proximal humerus reconstruction in orthopedic oncology

“…Technique: Prior to surgery, the planned resection of the humerus should be measured on the preoperative advanced imaging [23] . This is important to ensure that the appropriate length proximal humeral allograft is available during the surgery.…”