Buried or exposed Kirschner wire for the management of hand and forearm fractures: A systematic review, meta-analysis, and meta-regression

The recommendation on whether to bury or expose the Kirschner wire (K-wire) for the management of fractures has still been controversial with inconsistent results in the published studies due to the potential issue associated with exposed K-wire is the heightened risk of infection, as it comes into direct contact with the external environment and air. This study aims to summarize the specific outcomes between buried and exposed K-wire for the management of hand and forearm fractures. We conducted relevant literature searches on Europe PMC, Medline, Scopus, and Cochrane Library databases using specific keywords. This investigation focuses on individuals of any age diagnosed with hand or forearm fractures who underwent surgery involving Kirschner wire (K-wire) fixation. It examines the comparison between buried and exposed K-wire fixation, emphasizing primary outcome pin infection, along with secondary outcomes such as early pin removal, days to pin removal, and surgical duration. The study includes observational studies (cohort/case-control) or randomized clinical trials (RCTs). The results of continuous variables were pooled into the standardized mean difference (SMD), while dichotomous variables were pooled into odds ratio (OR) along with 95% confidence intervals using random-effect models. The quality of included studies was assessed with Cochrane Collaborations, Risk of Bias version 2 (RoB v2). A total of 11 studies were included. Our pooled analysis revealed that buried K-wire was associated with a lower risk of pin site infection [RR 0.49 (95% CI 0.36-0.67), p < 0.00001, I2 = 0%] and 33.85 days longer duration until pin removal [MD 33.85 days (95% CI 18.68-49.02), p < 0.0001, I2 = 99%] when compared with exposed K-wire. However, the duration of surgery was 9.98 minutes significantly longer in the buried K-wire [MD 6.98 minutes (95% CI 2.19-11.76), p = 0.004, I2 = 42%] with no significant difference in the early pin removal rate [RR 0.73 (95% CI 0.36-1.45), p = 0.37, I2 = 0%]. Further regression analysis revealed that sample size, age, sex, and duration of follow-up did not affect those relationships. Buried K-wire may offer benefits in reducing the infection rate with a longer duration until pin removal. However, further RCTs with larger sample sizes are still needed to confirm the results of our study.