Radiological parameters in the evaluation of functional outcomes following locking plate fixation of comminuted proximal humerus fractures

Background: The incidence of PHF is about 5% of all fractures that are clinically treated and is more common in elderly females. Locking plates are commonly used for fracture stabilization and provide stable fracture management. But some problems like reduction loss and varus malunion can have a great effect on functional outcomes. This study aimed to assess the role of radiological parameters-neck-shaft angle (NSA) and humeral head height (HHH)-in predicting functional outcomes in comminuted PHF treated with locking plates. Methods: A retrospective study was done on 50 patients who were treated at Pradyumna Bal Memorial Hospital, KIMS from July 2018 to July 2019 with a minimum followup of one year. The Constant Shoulder Score (CSS) was used to assess functional outcomes. Radiographic parameters were assessed at 1 month, 3 months, 6 months and 1 year after surgery. Data was analysed using Jamovi software version 2.3.28. Results: The mean age of the study participants was 54 +/-(19) years, which included 29 (58%) males and 21 (42%) females. The fracture union was obtained in 44 (88%) patients and 6 (12%) patients needed revision surgery. The postoperative NSA was 130° (range 120° to 140°) and was found to be related to the higher CSS scores. Patients with optimal NSA and HHH (44 patients, 88%) had significantly better functional outcome (CSS ~85), while patients with nonunion or suboptimal alignment had lower scores (CSS ~60, p<0.05). Conclusions: Radiological alignment plays an important role in functional outcome following PHF treated with locked plates. A large NSA (>125°) and adequate humeral head height prevent varus malunion and improve shoulder function after surgery. Optimum recovery will be achieved with careful surgical planning and restoration of anatomical alignment.