[Persistent radial palsy after humeral diaphyseal fracture: cause, treatment, and results. 30 operated cases].

PURPOSE OF THE STUDY: Radial palsy is a serious complication of humeral shaft fractures. The risk results from the anatomic position of the radial nerve which turns around the distal portion of the humeral shaft, in contact with the bone. As a rule, radial palsy regresses spontaneously, but in a few cases surgery may be required to achieve neurological recovery. We conducted a retrospective study of thirty cases of radial palsy after humeral fracture treated surgically. Our objective was to define causes of non-recovery and assess therapeutic efficacy, searching for the characteristic features of the fractures involved.

MATERIAL AND METHODS: We limited our analysis to post-humeral fracture radial palsies, which were operated due to the absence of neurological recovery. We recorded the type of fracture, treatment used to achieve bone healing, surgical approach, and type of radial nerve surgery. The series included 30 patients, predominantly male, mean age 38.4 years. The fractures were situated in the middle or lower third of the humeral shaft. Most were spiral fractures. Plate fixation (30%) or nailing (33%) were generally used for fixation. There were six cases of iatrogenic palsy, all after plate fixation. A revision procedure was required in one-third of the cases due to nonunion. Exploration of the radial nerve demonstrated compression at the intermuscular septum in one-third of the cases and a direct conflict with the fixation plate in one-fifth of the cases. Neurolysis was required in 23 cases, nerve grafts in five and first-intention tendon transfer in two.

RESULTS: Results of nerve surgery were assessed with the Alnot classification at a mean follow-up of 6.3 years. Outcome was rated good or very good in 22 patients, fair in one and poor (failure) in three. First-intention tendon transfers were performed in two patients and two patients were lost to follow-up. Mean delay to recovery was seven months after neurolysis and fifteen months after nerve grafts.

DISCUSSION: Our experience and data in the literature suggest that several factors could be involved in persistent radial palsy after humeral shaft fracture. The greatest risk of radial nerve injury or absence of recovery after the primary lesion is encountered after fracture of the lower third of the humerus, spiral fracture, and plate fixation. Particular features observed in our series were nonunion and compression in the intermuscular septum.