Postoperative radial nerve palsy in humeral shaft nonunion reconstruction: Can the lateral paratricipital approach prevent this common complication?

BACKGROUND: Postoperative radial nerve palsy (RNP) is a well-known complication of nonunion reconstruction of the humerus. The purpose of the current study is to determine if the surgical approach for nonunion reconstruction of the humerus influences the rate of postoperative radial nerve palsy. METHODS: A retrospective case-control study of all humeral shaft and extraarticular distal humerus nonunion reconstructions performed between January 1, 2004, and August 31, 2021, was conducted. Patients included were over 18 years of age, had a non-pathologic humerus fracture nonunion and had intact radial nerve function prior to nonunion reconstruction. Exclusion criteria consisted of nonunions involving the proximal humerus, intraarticular fractures, and reconstructive treatment procedures with either intramedullary nail or external fixation methods. Perioperative variables were recorded and analyzed in regard to the development of postoperative RNP. A subgroup analysis was performed to assess the interaction of significant variables on the development of postoperative RNP. RESULTS: The overall rate of postoperative RNP in this series was 6/53 (11%). However, no cases of postoperative radial nerve palsy were observed in patients who underwent nonunion reconstruction with a lateral paratricipital approach. A new RNP was seen in 4/9 (44%) of those patients who underwent a triceps splitting approach, which was significantly higher than those utilizing either an anterolateral approach (2/28, 7%) or a lateral paratricipital approach (0/16, 0%, p = 0.007). DISCUSSION AND CONCLUSION: Our data suggests that the lateral paratricipital exposure decreases the risk of radial nerve injury with nonunion reconstruction of the humerus. The lateral paratricipital exposure offers the benefit of radial nerve exploration, decompression, neurolysis and protection prior to fracture manipulation and instrumentation. This study shows conventional approaches may predispose patients to a high rate of postoperative RNP, similar to that in the literature.