Fibular allograft augmentation shows potential benefits in treating medial column comminuted proximal humeral fractures with osteoporosis: a secondary analysis of a randomized controlled trial

BACKGROUND: Fibular allograft (FA) augmentation is proposed to address the lack of medial column support in plate-fixed proximal humeral fractures; however, the role of FA augmentation in these fractures remains inadequately elucidated. Our previous clinical trial did not show additional benefit in inserting an FA when treating adults with medial column comminuted proximal humeral fractures. Nonetheless, it is possible that some subgroups may still derive benefits from FA. This study aimed to investigate whether there were any subgroups benefit from FA. MATERIALS AND METHODS: Our randomized controlled trial (RCT) recruited adults with a medial column comminuted proximal humeral fracture and randomly allocated them to receive a surgery fixed with a locking plate (LP group) or with an LP augmented with an FA (FA group). This study was a subsequent subgroup analysis of the previous randomized controlled trial, in which we included 72 participants who completed follow-up at the time of 12 months for the current subgroup analysis. The primary outcome was the Disabilities of the Arm, Shoulder and Hand (DASH) score at 12 months postoperatively. The secondary outcomes included the DASH score at other time points, changes in neck-shaft angle and humeral head height. We used generalized linear models for subgroup analysis to evaluate the effect of intervention (FA or LP) on 12-month DASH score in subgroups. RESULTS: A total of 72 participants who completed follow-up at 12 months were included: 35 were in the FA group and 37 in the LP group. In participants with proximal humeral osteoporosis, both the unadjusted mean difference (-12.8; 95% confidence interval (CI) -22.2 to -3.2; p = 0.01) and the adjusted mean difference (-11.1; 95% CI -20.0 to -2.2; p = 0.02) in the 12-month DASH score were statistically significant. Furthermore, in proximal humeral osteoporosis category, the DASH scores at other time points showed the similar trends though did not reach statistical significance. CONCLUSIONS: FA augmentation seemed to have added values in treating osteoporotic proximal humeral fractures in combination with medial column comminution. LEVEL OF EVIDENCE: Level II, therapeutic study. TRIAL REGISTRATION: ChiCTR-IOR-16008817.