Outcomes, Union Rate, and Complications After Operative and Nonoperative Treatments of Neer Type II Distal Clavicle Fractures: A Systematic Review and Meta-analysis of 2284 Patients

Background: As nonoperative treatment of Neer type II distal clavicle fractures is associated with nonunion rates up to 33%, operative treatment is frequently advocated. However, evidence is lacking regarding which operative treatment to perform and whether this is superior to nonoperative treatment in terms of functional outcome and complication rate. Purpose: (1) To evaluate which surgical technique in the treatment of Neer type II distal clavicle fractures is optimal with regard to patient-reported outcomes and union and complication rates. (2) To review nonoperatively treated patients. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review of the literature and meta-analysis were performed on January 27, 2021, in PubMed, Embase, CENTRAL, CINAHL/EBSCO, Web of Science/Clarivate Analytics, and SPORTDiscus/EBSCO. The search included all studies regarding nonoperative and operative treatment of Neer type II distal clavicle fractures with a minimum of 20 patients and follow-up of 12 months. The primary and secondary outcomes were patient-reported outcome measures at 12 months and union, complication, and revision rates. Results: A total of 59 articles were included involving 2284 patients. Coracoclavicular fixation, hook plate, transacromial pins, alternative plate, tension band wire/K-wire, a combination of surgical techniques, and a nonoperative group were described. Hook plates showed lower Constant-Murley scores as compared with coracoclavicular fixation (standard mean difference, -0.77; 95% CI, -1.26 to -0.28; P = .002). However, no significant difference was seen when the hook plate was compared with the locking plate and tension band wire/K-wire groups, and no significant difference in union rate was seen among all operative treatment groups. Operatively treated patients had significantly higher union rates than patients treated nonoperatively (standard mean difference: 0.05; 95% CI, 0.01 to 0.37; P = .004). Conclusion: Patients treated with hook plates showed significantly lower Constant-Murley scores and higher complication and revision rates as compared with those treated with coracoclavicular fixation, without differences in union rate. Higher Constant-Murley scores were seen in those patients with supplemental coracoclavicular fixation when using locking. Nonoperatively treated patients showed good functional outcome despite the 31% nonunion rate, although future studies are necessary to substantiate this conclusion. When using a locking plate, additional craniocaudal fixation showed significant better functional outcome.