The impact of residual angulation on patient reported functional outcome scores after non-operative treatment for humeral shaft fractures

Purpose To determine if residual angular deformity following non-operative treatment of humeral diaphyseal fractures correlates with patient reported outcomes. Methods Skeletally mature patients treated by one of three orthopaedic trauma surgeons at a level 1 trauma centre with humeral shaft fractures treated without surgery were retrospectively identified over a 7 year period. After inclusion and exclusion criteria, 42 patients were eligible for the study. Disabilities of the Arm, Shoulder, and Hand (DASH); Simple Shoulder Test (SST); General health questionnaire SF-12 physical component summary (SF-12 PCS) and mental component summary (SF-12 MCS) were obtained from study participants. Healed angular deformity was obtained from patient charts. Results Thirty two subjects were successfully recruited (32/42 or 76%). Average age was 45 ± 22 with average study follow up being 47 ± 29 months. Average outcome scores were DASH 12 ± 16, SST 10 ± 2.7, SF-12 PCS 50 ± 7.9, and SF-12 MCS 54 ± 8.8. Healed sagittal plane deformity averaged 8 ± 5.7° [range 0−18], and 15 ± 7.9° [range 2−27] in the coronal plane. There was no correlation between residual sagittal or coronal plane deformity and outcome scores (DASH and SST for both p > 0.05). Patients with at least 20° (n = 7; 22%) of healed coronal deformity had similar outcomes to those with <20° ([DASH (13.2 ± 18.7 vs 11.7 ± 16.1; p = 0.83]; [SST (10.3 ± 2 vs 10.0 ± 2.9; p = 0.81]). Higher SF-12 PCS and MCS scores correlated with better DASH and SST scores (p < 0.05 for all). Conclusion Residual angular deformity ranging from 0 to 18° in the sagittal plane and from 2 to 27° in the coronal plane after non-operative treatment for humeral shaft fractures had no correlation with patient reported DASH scores, SST scores, or patient satisfaction. Instead, overall physical and mental health status as measured by the SF-12 significantly correlated with patient reported outcomes.