Factors influencing shoulder stiffness after open reduction and internal fixation of proximal humeral fractures.

Objectives: The study aimed to investigate the factors associated with shoulder stiffness following open reduction and internal fixation (ORIF) of proximal humeral fractures.

Patients and methods: The retrospective study included a total of 151 patients who underwent ORIF of proximal humeral fractures between January 2016 and May 2021. Based on their shoulder joint motion at the latest follow-up, the patients were divided into two groups. The stiffness group (n=32; 8 males, 24 females; mean age: 62.4±9.3 years; range, 31 to 79 years), exhibited restricted shoulder forward flexion (<120°), limited arm lateral external rotation (<30°), and reduced back internal rotation below the L3 level. The remaining patients were included in the non-stiffness group (n=119; 52 males, 67 females; mean age: 56.4±13.4 years; range, 18 to 90 years). Various factors were examined to evaluate the association with shoulder stiffness following ORIF of proximal humeral fractures by multivariate unconditional logistic regression models.

Results: The mean follow-up duration was 31.8±12.6 (range, 12 to 68) months. Based on the results of the multivariate regression analysis, it was found that high-energy injuries [compared to low-energy injuries; adjusted odds ratio (aOR)=7.706, 95% confidence interval (CI): 3.564-15.579, p<0.001], a time from injury to surgery longer than one week (compared to a time from injury to surgery equal to or less than one week; aOR=5.275, 95% CI: 1.7321-9.472, p=0.031), and a body mass index (BMI) >24.0 kg/m² (compared to a BMI between 18.5 and 24.0 kg/m² ; aOR=4.427, 95% CI: 1.671-11.722, p=0.023) were identified as risk factors for shoulder stiffness following ORIF of proximal humeral fractures.

Conclusion: High-energy injury, time from injury to surgery longer than one week, and BMI >24.0 kg/m² were identified as independent risk factors for shoulder stiffness after proximal humeral fracture surgery, which should be treated with caution in clinical treatment.