457 - Posterior Interosseous Nerve (PIN) Syndrome in an Otherwise Healthy 43-year-old Firefighter: A Case Study

This case study provides an example of PIN syndrome in an otherwise healthy 43-year-old male after working on fire crews two summers in a row. 

Case Description:

A 43-year-old right hand dominant male presented to the PM&R clinic with right hand weakness for EMG consultation. He worked on a fire crew two summers in a row, during which time he carried a heavy chainsaw and backpack regularly. Since working on the fire crews, he noticed gradual weakness of the right hand. Manual muscle testing revealed finger drop and wrist extensor weakness on the right. Muscle stretch reflexes were +1/4 in the biceps, brachioradialis and triceps. Tinel’s sign at the wrist and Phalen’s sign were negative. The electrodiagnostic studies were consistent with a radial neuropathy on the right, predominantly involving the posterior interosseous branch of the radial nerve. Active denervation with no signs of reinnervation was noted, and the patient was referred to a hand surgeon for further evaluation and management. 

Discussions:

The posterior interosseous nerve is a branch of the radial nerve and provides motor innervation to the extensor muscles of the forearm. Initial management of PIN syndrome includes rest, bracing, NSAIDs and physical therapy. If there is no improvement after 3 months of conservative management, surgery is usually considered. Without intervention, muscle atrophy and fibrosis occurs, and tendon transfers are a last resort surgical option.1 As the patient presented above had been experiencing symptoms for several years, referring to orthopedic surgery was the most appropriate next step in management. In general, radial nerve decompression surgeries are not as successful as carpal or cubital tunnel decompression surgeries.2 

Conclusions:

This case study provides an example of PIN syndrome for which conservative management was no longer an option and referral to orthopedic surgery was necessary, highlighting the importance of early intervention.