Evaluating the association of radiographic parameters of proximal humerus fractures managed conservatively with functional outcomes.

Introduction: Treatment of proximal humerus fractures remains controversial. Understanding the factors that can affect the long-term functional outcomes can aid with management choices. This primary aim of this paper is to evaluate the association of radiographic parameters with functional outcomes.

Methods: Radiographic parameters [Caput-collum-diaphyseal (CCD) angles, Y-scapular angles, and humeral head height (HHH)] were studied. The patients were split into varus and valgus groups based on the CCD angles and retroverted and anteverted groups based on Y-scapular angles. Functional outcome was measured by Oxford Shoulder Score (OSS), Constant Shoulder Score (CSS), and quick Disabilities of Arm, Shoulder and Hand score at 1 year follow-up. Intra- and interrater reliability were measured with the intraclass correlation coefficients (ICCs). Receiver operator curve (ROC) analysis and logistic regression analysis defined the optimal value for abnormalities on radiographic evaluation as an outcome predictor.

Results: 111 patients were recruited (mean age 69, 78% female). Median final radiographic assessment was at 7 months. Mean initial/final CCD was 119 /111 (varus, n = 36) and 153/140 (valgus, n = 75). Mean initial/final Y-scapula angle was 27/27 (retroversion, n = 101) and 70/40 (anteversion, n = 9). There was a significant relationship between OSS and final Y-scapular angle in the retroverted group (adj coeff 0.034, p = 0.009) with optimum predictive retroversion angulation of 25 predicting poor functional outcome (OSS < 40), area under the ROC curve of 0.614. Higher initial valgus and retroversion significantly predicted more change in the final angle (adj coeff - 0.349, p = 0.002, adj coeff - 0.527, p < 0.001 respectively). Both intra-rater and inter-rater reliability for the radiographic parameters were excellent (ICC > 0.9).

Conclusion: Radiographic parameters whilst having excellent reliability, have a limited ability to predict short-term functional recovery. The extent of retroversion is the most important predictor for functional recovery with 25 a cut-off guide. Fractures with a higher initial valgus and retroversion tend to displace more.