Functional outcomes and postoperative shoulder stiffness in patients with proximal humerus fractures treated with PHILOS plating: A retrospective study

Background: Data on the functional outcomes and shoulder stiffness following treatment with proximal humeral internal locking system (PHILOS) plates for proximal humerus fractures (PHFs) are limited. This study aims to evaluate the functional outcomes and postoperative shoulder stiffness, as well as their predictors, in PHF patients treated with PHILOS plates. Methods: This retrospective study included 53 patients with PHF who underwent surgical treatment using PHILOS plates between January 2021 and January 2023. The primary endpoint measured was the Constant-Murley Score (CMS) and its associated factors, while secondary outcomes included variables related to shoulder stiffness. Results: Over a mean follow-up period of 19.6 ± 4.0 months, the union was achieved in 47 patients (89.3%). The mean postoperative CMS and Disabilities of the Arm, Shoulder, and Hand (DASH) scores were 83.6 ± 10.4 and 23.6 ± 6.93 points, respectively. The CMS was rated excellent in 18 patients (34.0%), good in 20 patients (37.7%), fair in nine patients (17.0%), and poor in six patients (11.3%). Complications arose in 34% of patients, notably shoulder stiffness (22.6%), followed by screw penetration and varus malunion (both 5.7%). Postoperative CMS was positively associated with DASH score (r = 5.35, p < 0.001) and comorbidities (r = 2.88, p = 0.003). Conversely, it was negatively associated with age (r = −3.22, p = 0.014) and complications (r = −3.40, p = 0.005). In multivariate analysis, only high-energy injuries were identified as independent predictors of shoulder stiffness (adjusted odds ratio, 10.07 [95% CI, 1.06–95.81]; p = 0.045). Conclusion: PHILOS plating demonstrates a reliable approach for managing PHFs, achieving a commendable union rate of 89.3% and positive functional outcomes. Postoperative CMS results are significantly affected by patient comorbidities and specific fracture characteristics. Furthermore, the predictive value of high-energy injuries on shoulder stiffness is crucial in devising targeted strategies to optimize recovery and reduce complications. These insights emphasize the importance of tailoring treatment plans to individual patient profiles, thereby enhancing the overall effectiveness of PHF management.