Cadaveric studies suggest that the acceptable deformity in fifth metacarpal neck fractures is maximally 30° palmar angulation. This systematic review verifies the validity of these threshold values. Eighteen prospective comparative studies on operative and/or conservative treatment options in adults were included. None of the studies demonstrated any correlation between the residual or initial angulation and the clinical results despite accepting more severe angular deformities. Closed reduction and immobilization without internal fixation improved the palmar angle by 5° to 9° in three studies and 29° in a fourth. Operative treatments compared with non-reducing conservative treatments showed no benefit of the surgery other than aesthetic issues. The synthesis of this review indicates that 90% of fractures of the metacarpal neck with apex angulation up to 70° can be treated successfully with a functional metacarpal brace without reduction. Disability of the Arm, Shoulder and Hand questionnaire scores <10 are uniformly reported. I modified my own practice accordingly a decade ago to treating these fractures conservatively regardless of the palmar angulation, except in patients with exceptional demands or other fracture deformities.
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