JSES - 2026-08-01 - Journal Article
Analysis of factors influencing fragment displacement in greater tuberosity fractures: the number of involved facets as a key risk factor.
Yoshida Y, Yoshida A
Topics
Key Takeaway
In isolated greater tuberosity fractures, involvement of all 3 rotator cuff attachment facets is the strongest independent predictor of ≥5 mm displacement (OR 7.72; 95% CI 3.06–19.44), outweighing the presence of anterior dislocation.
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Summary
This study examined factors predicting ≥5 mm fragment displacement in 102 isolated GT fractures using 3D CT, evaluating facet involvement (superior, middle, inferior), fracture type (avulsion, split, depression), and presence of anterior dislocation. On multivariate logistic regression, 3-facet involvement was the dominant independent predictor (OR 7.72), while depression-type fractures were strongly protective against displacement (OR 0.05), and dislocation lost independent significance after adjustment (OR 3.01, P=.071). Among 34 nonoperatively managed shoulders, secondary displacement occurred in 4 cases, concentrated in 3-facet and split-type fractures.
Key Limitation
The study lacks patient-reported outcome data, so the clinical consequence of the displacement risk stratification—whether facet-count-guided operative versus nonoperative selection actually improves functional outcomes—remains unvalidated.
Original Abstract
BACKGROUND
Fragment displacement is a key determinant of treatment strategy and functional outcomes in isolated greater tuberosity (GT) fractures. However, the relative contributions of fracture morphology and shoulder dislocation to displacement remain unclear. This study aimed to identify factors associated with fragment displacement, with a particular focus on facet involvement, fracture type, and the presence of shoulder dislocation using three-dimensional computed tomography (CT). Secondary displacement during nonoperative management was also explored.
METHODS
We retrospectively analyzed 102 shoulders (mean age 64.5 ± 14.5 years) with isolated GT fractures, including shoulders with and without anterior dislocation. Using three-dimensional CT images obtained at the time of injury, fracture morphology was evaluated based on the number of rotator cuff attachment facets (superior, middle, and inferior) and fracture type, classified as avulsion, split, or depression. Fragment displacement was defined as ≥5 mm translation in any direction and was assessed on postreduction CT in dislocation cases. Associations between fragment displacement, fracture morphology, and the presence of dislocation were analyzed using chi-square tests and multivariate logistic regression. Secondary displacement during follow-up was evaluated in nonoperatively managed shoulders using standard radiographs.
RESULTS
Overall, 65 shoulders (63.7%) exhibited ≥5 mm displacement. Displacement correlated significantly with the number of involved facets (P < .001), fracture type (P = .008), and dislocation (P = .011). In the displaced group, 3 facets were involved in 49 shoulders, compared with only 8 in the nondisplaced group. Multivariate logistic regression identified facet count as the strongest independent factor (odds ratio [OR] 7.72; 95% confidence interval 3.06-19.44; P < .001). Compared with avulsion-type fractures, depression-type fractures showed a significantly lower risk of displacement (OR 0.05; 95% confidence interval 0.005-0.415; P = .006). Dislocation was associated with displacement on univariate analysis but did not remain an independent predictor after adjustment (OR 3.01; P = .071). Among 34 nonoperatively managed shoulders, secondary displacement occurred in 4 cases and was more frequently observed in fractures involving 3 facets and in split-type fractures.
CONCLUSION
Fragment displacement in GT fractures is most strongly associated with the number of involved facets, suggesting that the extent of rotator cuff attachment has a major influence on fragment stability. Although dislocation was associated with an increased risk of displacement, facet morphology was the decisive determinant. CT-based assessment of facet involvement provides valuable information for understanding displacement risk in GT fractures.