(P 280) COMPLEX SHOULDER EXTRA-ARTICULAR RESECTION AND RECONSTRUCTION: A NOVEL DESIGN

Objective: The proximal humerus is a common location for malignant bone lesions. The treatment gold standard includes tumor resection with adequate margins, limb preservation being appropriate for the majority of patients. Approximately a fourth of the patients will require an extra-articular resection to achieve oncologic margins, a procedure known to be skillfully demanding and associated with less than perfect outcomes with a considerable rate of revisions required throughout the patient’s lifetime. Here we present a reconstruction technique with a novel custom-made implant and 3 patient cases with good postsurgical functional outcomes.

Methods: A novel shoulder reconstruction implant was designed for patients where both rotator cuff and deltoid function is lost. It consists of two constrained joints in serial fashion to limit transfer of forces to the glenoid component whilst still preserving a full constrained design. The implant is made of 3-D printed titanium with a diamond-like carbon (DCL) surface and strong polyetheretherketone (PEEK) inlay. Soft tissue reconstruction was performed utilizing a polyethylene terephthalate tube. All three cases were performed by the same surgical team. Functional and oncologic outcomes were analyzed.

Results: Three patients agreed to participate and received a custom-made shoulder reconstruction device. Two patients had a telangiectatic osteosarcoma of the proximal humerus complicated with a pathological fracture and one patient had an unplanned resection of what was later diagnosed as synovial sarcoma. All three patients required the resection of the axillary nerve to achieve oncologic margins as well as an extra-articular resection including transection of rotator cuff tendons at the level of the scapular neck. Patients were seen to follow up at 2 and 6 weeks for wound assessment. Physical therapy was allowed after 6 weeks starting with pendulum exercises. At the latest follow up all three patients had good function and an acceptable MSTS score. All patients were pain free and had a stable shoulder joint. Passive abduction was possible up to 95 degrees, after which point implant impingement was noted. No acute complications occurred. No local recurrences occurred. The only later patient complaint was an altered shoulder figure with protruding implant which was well tolerated and accepted by all.

Conclusion: In the setting of young age patients with potentially good oncologic prognosis, achieving acceptable function permissible of a good quality of life is paramount. Reconstruction alternatives are scarce presently and are often associated with less than perfect outcomes. The presented novel implant with a design including two constrained joints in serial fashion has shown to be a promising alternative for reconstruction in these challenging cases.