Disclosures: Matthew A. Cascio, DO: No financial relationships or conflicts of interest
Sukhdeep S. Bains, DO: No financial relationships or conflicts of interest

Case Diagnosis: 76-year-old female with posterior interosseous nerve palsy following open reduction internal fixation of Monteggia fracture

Case Description or Program Description: A 76-year-old female presented for evaluation of posterior interosseous nerve palsy after open reduction internal fixation for a right Monteggia fracture and right radial head arthroplasty. She sustained the injury after a mechanical fall. She had difficulty extending her wrist and fingers. She had limited range of motion in wrist flexion, extension and finger extension and 3/5 strength in wrist flexion, extension and handgrip, and 0/5 in finger extension.

Setting: Outpatient

Assessment/Results: On nerve conduction study, the right radial nerve at the forearm and elbow was nonresponsive. EMG of the right extensor digitorum communis showed increased insertional and spontaneous activity. The right extensor indicis showed increased insertional activity, spontaneous activity, polyphasic potentials, and early recruitment. Patient was diagnosed with axonal posterior interosseous neuropathy with muscle denervation.

Discussion (relevance): A Monteggia fracture is a fracture of the proximal ulna and dislocation of the radial head. They account for 1-2% of all forearm fractures. It is most commonly due to direct trauma to the forearm with the elbow extended and forearm hyperpronated. Fractures in elderly females are usually due to falls. These fractures are considered unstable and require surgical intervention, usually with open reduction internal fixation. Posterior interosseous nerve palsy occurs in about 10% of injuries. Nerve injuries rarely require treatment as they self-resolve in 9 to 12 weeks.

Conclusions: Although nerve injuries are relatively rare in Monteggia fractures, they must be considered if patients exhibit motor and sensory deficits. In this case, the patient developed posterior interosseous palsy leading to weakness in wrist flexion, wrist extension and finger extension. Despite these deficits, there is a good prognosis as symptoms usually self-resolve. The goal of rehabilitation is the return of full range of motion and fine motor skills with the absence of pain.

Level of Evidence: Level III

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/posterior-interosseous-nerve-palsy-following-monteggia-fracture/