Review Question - QID 214865

The patient has sustained a closed humerus fracture with a pre-operative radial nerve palsy that has remained persistent 2 months following surgery. The most appropriate next step in management is to proceed with nerve conduction studies (NCS) and electromyography (EMG).

Closed humeral shaft fractures are associated with radial nerve palsy at a rate of 10-15% with distal 1/3rd shaft fractures having shown a slightly higher rate (22%). Spontaneous recovery occurs in 85-90% of cases over the course of 3-6 months. If there is no sign of recovery after 1-2 months, an EMG/NCS is recommended to document the extent of nerve damage, to determine a baseline of function, and to monitor recovery. If no further improvement is noted, repeat EMG/NCS can be obtained at ~4 months to monitor for any recovery. There has been no evidence of deleterious effects occurring during this observation period. Exploration in the intermediate period between 1 and 4 months is not supported.

DeFranco et al. review the principals of management of radial nerve injuries associated with humeral shaft fractures. They note that EMG/NCS play no role in the acute setting following a radial nerve injury associated with a closed humerus fracture. The authors recommend that if patients do not show clinical improvement by ~2 months after the initial injury, then obtaining an EMG is the next appropriate step. They note that EMG at this stage is useful as it can be used to establish a baseline of function and to monitor recovery.

Shao et al. performed a systematic review of radial nerve palsy associated with closed humeral shaft fractures. The authors noted an overall prevalence of radial nerve palsy after closed humerus shaft fractures of 11.8% (532 palsies in 4517 fractures in 21 papers). The overall rate of recovery was 88.1%. They noted a mean onset of recovery at 7 weeks with a mean full recovery time of 6 months (range 3.4-12 months) for those managed conservatively. They noted a mean time to the nerve exploration of 4.3 months. The authors noted no difference in patient outcomes when comparing groups that were initially managed expectantly compared to those explored early (within 3 weeks). The authors concluded there is no benefit to early exploration of radial nerve palsies associated with closed humeral shaft fractures.

Figure A shows a humeral shaft fixation with a plate and screw construct.

Incorrect Answers:
Answer 1: Continued observation for an additional 6 months is not appropriate without an EMG/NCS
Answer 2: The patient is only 2 months out from his injury/onset of radial nerve palsy. He may still recover significant function and is not a candidate for tendon transfer
Answer 4 and 5: Given that the radial nerve palsy was present pre-op and that the nerve was visualized and protected during the surgical procedure, the next best step is an EMG/NCS to document the extent of nerve damage, to determine a baseline of function, and to monitor recovery.