Radial nerve palsy associated with closed humeral shaft fractures: a systematic review of 1758 patients

BACKGROUND AND PURPOSE: Humeral shaft fractures are often associated with radial nerve palsy (RNP) (8–16%). The primary aim of this systematic review was to assess the incidence of primary and secondary RNP in closed humeral shaft fractures. The secondary aim was to compare the recovery rate of primary RNP and the incidence of secondary RNP between operative and non-operative treatment. METHODS: A systematic literature search was performed in ‘Trip Database’, ‘Embase’ and ‘PubMed’ to identify original studies reporting on RNP in closed humeral shaft fractures. The Coleman Methodology Score was used to grade the quality of the studies. The incidence and recovery of RNP, fracture characteristics and treatment characteristics were extracted. Chi-square and Fisher exact tests were used to compare operative versus non-operative treatment. RESULTS: Forty studies reporting on 1758 patients with closed humeral shaft fractures were included. The incidence of primary RNP was 10%. There was no difference in the recovery rate of primary RNP when comparing operative treatment with radial nerve exploration (98%) versus non-operative treatment (91%) (p = 0.29). The incidence of secondary RNP after operative and non-operative treatment was 4% and 0.4%, respectively (p < 0.01). INTERPRETATION: One-in-ten patients with a closed humeral shaft fracture has an associated primary RNP, of which > 90% recovers without the need of (re-)intervention. No beneficial effect of early exploration on the recovery of primary RNP could be demonstrated when comparing patients managed non-operatively with those explored early. Patients managed operatively for closed humeral shaft fractures have a higher risk of developing secondary RNP. LEVEL OF EVIDENCE: Level IV; Systematic Review. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s00402-020-03446-y) contains supplementary material, which is available to authorized users.