Efficacy of the shape-memory alloy ring hugger and microplate in proximal clavicle fractures

Abstract

The efficacy and safety of shape-memory alloy (SMA) ring hugger and microplate in the treatment of proximal clavicle fractures were compared to better improve the quality of patient rehabilitation and minimize complications. The mechanical properties of Ni-Ti alloy and Ti64Al4V (compressive strength and elastic modulus) were examined in the physicochemical property tests, while, mouse osteoblasts were cultured to test their biocompatibility. Subsequently, clinical data of patients with clavicle fractures treated at our hospital from January 2012 to January 2022 were retrospectively analyzed. The patients were divided into microplate and SMA groups based on the surgical methods, and the follow-up period was 1 year post-surgery. Clinical treatment, mobility and functional recovery (DASH score and Constant score) of the affected upper limb, numbness, and adverse effects were compared between the two groups. SMA exhibited a compressive strength similar to that of Ti6Al4V, but its modulus of elasticity was significantly lower. Meanwhile, the results of the cellular experiments suggested that the addition of SMA and Ti6Al4V would not markedly decrease the osteoblast activity, suggesting that both internal fixation implants had good biocompatibility. In addition, SMA ring hugger was effective in reducing operative time, intraoperative bleeding, wound size, fracture end healing time, and residual fracture shortening. In terms of postoperative assessment of affected limb mobility, SMA ring hugger better improved the mobility of the affected shoulder in supination, abduction, adduction, and forward flexion, and was more effective in decreasing the DASH score and increasing the Constant score. Meanwhile, SMA ring hugger effectively reduced numbness in the affected area and decreased the incidence of delayed wound healing, exercise restrictions, proliferative scars, and vegetative stimulus. Therefore, SMA ring hugger demonstrates favorable mechanical performance and biocompatibility, meanwhile, it can better promote postoperative functional recovery of the affected limb in clavicle fracture patients with guaranteed safety.