Clinical and radiographic outcomes of chronic anterior dislocations treated with reverse total shoulder arthroplasty

Reverse total shoulder arthroplasty (rTSA) for chronic locked anterior shoulder dislocations (CD) remains challenging due to glenoid bone loss, soft-tissue contractures, and risk of post-operative stiffness and instability. Outcomes of rTSA for CD remain poorly defined, particularly compared with rTSA for proximal humerus fractures (PHF), another high-risk indication associated with inferior results relative to traditional rTSA indications. This study evaluated clinical and radiographic outcomes of rTSA for CD vs. PHF. We hypothesized that patients with CD would demonstrate inferior post-operative outcomes compared with patients with PHFs.

A retrospective review was performed of all patients who underwent rTSA for CD or PHF between August 2015 and November 2024 at a single academic institution. Patients with CD were matched 1:3 to PHF controls using propensity scores, controlling for age at surgery, gender, body mass index, American Society of Anesthesiologists score, diabetes status, smoking status, insurance type, and follow-up duration. Collected variables included demographics, mechanism of injury, time to surgery after injury, and pre-operative radiographic findings. Post-operative outcomes included active forward elevation, active external rotation, internal rotation score, complications, and re-operations. Patient-Reported Outcomes Measurement Information System (PROMIS) scores, including PROMIS Upper Extremity, PROMIS Pain Interference, and PROMIS Pain Intensity scores were also recorded.

A total of 17 patients with CD were included in this study. Eleven patients had an isolated anterior dislocation, 6 patients had an associated glenoid fracture, and 3 had additional greater tuberosity fractures. The CD cohort collectively was then matched to 51 PHF controls. The mean follow-up duration was 28.1 (CD) and 20.9 (PHF) months (P = .39). There were no differences in the post-operative active forward elevation, active external rotation, or internal rotation measurements between the CD and PHF cohorts. Heterotopic ossification (capsular ossification) was more common in the CD group (23.5% vs. 3.9%; P = .04), but there were no differences in other complications,revision, or re-operation rates between the CD and PHF cohorts. The CD cohort demonstrated lower PROMIS Upper Extremity scores than the patients with PHF (36.2 ± 8.6 vs. 56.6 ± 9.8, P < .001). Patients with CD also had higher PROMIS Pain Interference scores (53.9 ± 9.0 vs. 46.2 ± 10.1, P = .03).

rTSA for CD results in lower functional outcome scores and higher pain interference scores but comparable range of motion when compared to rTSA for PHFs. The presence of a glenoid fracture or greater tuberosity fracture did not affect outcomes of rTSA in patients with CD.