High incidence of complications associated with shoulder girdle reconstruction utilizing a Stryker proximal humerus cap endoprosthesis following Tikhoff-Linberg resections.

INTRODUCTION: The Tikhoff-Linberg procedure is a limb salvage technique for tumours of the shoulder girdle which preserves function of the hand and elbow; however, shoulder function is limited. A humeral cap endoprosthesis (Stryker Orthopedics, Mahwah, NJ, USA) was developed within the Modular Replacement System (MRS) to act as a functional spacer for these defects; however, the outcomes of this implant have not been described. METHODS: Thirty-three (17 male, 16 female) patients underwent a Tikhoff-Linberg procedure at our institution. Of these, 17 (11 females, 6 males) were reconstructed with a MRS humerus endoprosthesis. Outcomes and complications were compared between patients who were reconstructed (n = 17) and those who were not (n = 16). RESULTS: Complications occurred in 14 (42%) patients, with more complications in patients who were reconstructed (n = 11, 65% vs. n = 3, 19%, p = 0.01). Endoprosthetic complications included stress shielding of the bone/prosthesis interface (n = 7, 41%) and subluxation/instability (n = 5, 29%), leading to a revision surgery in two (12%). Post-operatively, the mean Musculoskeletal Tumor Society Score (MSTS93) was 67 ± 11%, with no difference in the mean MSTS93 between patients who were reconstructed and those who were not (67 ± 10% vs. 68 ± 12%, p = 0.77). CONCLUSIONS: Reconstruction with a MRS humerus cap endoprosthesis resulted in a high rate of complications following a Tikhoff-Linberg procedure. Stress shielding and subluxation were common, and as such, the use of this prosthesis is limited to cases where a standard implant is not a feasible option.