Use of locking humeral stems in reverse total shoulder arthroplasty for complex proximal humerus fractures: a scoping review

The use of locked humeral stems in reverse total shoulder arthroplasty (rTSA) has emerged as an alternative fixation strategy for treating complex proximal humerus fractures (PHFs). This scoping review synthesizes the available literature evaluating clinical outcomes, radiographic findings, and complications associated with interlocking humeral stems in rTSA for PHFs. Nine studies, encompassing 434 patients, were identified, of whom 308 underwent rTSA with a locking humeral stem. The mean patient age was 75.7 ± 5.1 years, with a mean follow-up of 20.0 ± 8.9 months, and at least 54% of patients were female. Postoperative functional outcomes demonstrated a mean forward flexion of 120° ± 13.2°, abduction of 101° ± 2.3°, external rotation of 29.3° ± 8.9°, and internal rotation to the lumbar spine. Patient-reported outcomes showed a mean Quick Disabilities of the Arm, Shoulder, and Hand score of 31.4 ± 4.2 and a Constant-Murley Score of 65.4 ± 10.7. Tuberosity healing was observed in 76% of cases. The overall complication rate was 13.0%, with locking screw -related complications occurring in 1.6% of cases, accounting for 12.5% of all reported complications. These findings suggest that locked humeral stems provide reliable diaphyseal fixation with a low incidence of screw-related complications in rTSA for complex PHFs. Long-term success depends on achieving stable metaphyseal fixation and osteointegration; cemented or press-fit stems without screws remain viable alternatives. Further prospective, comparative studies are needed to clarify long-term outcomes and optimize implant selection.