Z-type Clavicle Fractures in Adults: A Retrospective Comparative Study of Outcomes.

INTRODUCTION: Midshaft clavicle fractures with a "Z" deformity have historically been considered a surgical indication, although evidence is limited. This study compared rates of surgery to promote fracture healing between Z-type and non-Z-type clavicle fractures managed nonoperatively (nonsurgical cohort) and all-cause unplanned (re)operation rates among operatively and nonoperatively managed Z-type fractures (Z-type cohort).

METHODS: This retrospective cohort study included adult patients with midshaft clavicle fractures treated at two level 1 trauma centers between 2010 and 2023. Z-type fractures were defined as comminuted fractures with complete displacement and a vertically oriented butterfly fragment of ≥1 cm. The primary outcome was the rate of surgery to promote fracture healing in the nonsurgical cohort and the all-cause unplanned surgery rate in the Z-type cohort.

RESULTS: In total, 35 nonsurgical Z-type fractures, 157 nonsurgical non-Z-type fractures, and 95 surgical Z-type fractures were included. Rates of surgery to promote healing were similar between nonoperatively managed Z-type and non-Z-type fractures (17% vs. 22%, P = 0.552). Multivariable analysis showed no association between Z-type fractures and surgery to promote fracture healing (odds ratio, 0.84; 95% confidence interval, 0.29 to 2.17; P = 0.737). Among Z-type fractures, all-cause unplanned surgery rates were comparable between nonsurgical and surgical management (20% vs. 28%, P = 0.333). However, when excluding implant removal, nonoperatively managed Z-type fractures had a significantly higher all-cause unplanned surgery rate (20% vs. 4.2%, P = 0.009). Surgical management of Z-type fractures had a lower rate of surgery to promote fracture healing compared with nonsurgical management (1.1% vs. 17%, P = 0.002).

CONCLUSIONS: Among fractures initially treated nonoperatively, Z-type and non-Z-type midshaft clavicle fractures had similar rates of surgery to promote fracture healing. Surgical management of Z-type fractures demonstrated a lower rate of surgery to promote fracture healing compared with nonsurgical management. Regardless of initial treatment, all-cause unplanned surgery rates were comparable for Z-type fractures.

LEVEL OF EVIDENCE: Therapeutic Level III.