Fact or fiction: the "5 mm Rule" in greater tuberosity fractures of the proximal humerus

The purposes of this study were 1) to assess the outcome of nonoperative management of GT fractures with > 5 mm of displacement and 2) to assess whether there is a correlation between degree of displacement and outcome.

This study was a retrospective review of consecutive low-energy GT fractures from 2011 to 2020. Radiographs from all visits were reviewed. The direction of maximal displacement was assessed. Subjects were stratified based on the amount of maximal displacement: Group 1: 0-5 mm, Group 2: 5-10 mm, Group 3: > 10 mm. Range of motion (ROM) at the time of final follow-up was assessed. The presence of persistent shoulder pain after healing was noted, as well as whether supplemental subacromial corticosteroid injection was provided as part of long-term treatment.

A cohort of 93 fractures comprised the study group. Mean age was 62 years. Mean follow-up was 20 months. All fractures went on to union. Mean displacement was 6.2 mm. There were 43 patients in Group 1, 43 in Group 2, and 7 in Group 3. Maximal displacement was most commonly inferolateral or lateral, accounting for a combined 77% of all patients. There was no difference in final ROM between displacement groups, with at least 155 degrees of forward elevation and 45 degrees of ER in all three groups. There was no difference between Group 1 and Groups 2/3 in frequency of persistent pain or likelihood of receiving a steroid injection.

Our findings do not support a discrete 5 mm displacement threshold for surgical repair of isolated greater tuberosity fractures.