Incidence of Posterior Interosseous Nerve Trauma During Creation of the 3-4 Wrist Arthroscopy Portal in Cadavers

Purpose To describe histologic evidence of nerve trauma during the creation and use of the 3-4 portal. Methods Fourteen fresh-frozen cadaveric wrists were mounted on a custom-built frame that simulated a wrist arthroscopy traction tower. After the 3-4 portal was created in the usual manner, the skin was dissected off to identify possible trauma to the posterior interosseous nerve (PIN). Specimens were categorized into those where there was clearly no trauma to the PIN and those where trauma was possible. In the cases where trauma was possible, we harvested the PIN with a cuff of the proximal edge of the portal and examined the cross-sectional histology of the most distal sections for the presence of neural tissue. Results There was clearly no trauma to the PIN in 3 of the wrists during the creation of the 3-4 portal. In the remaining 11 wrists with possible trauma to the PIN, we identified axonal tissue on histologic examination at the proximal edge of the 3-4 portal in 7 of these specimens. In summary, 50% (7 of 14) of our specimens had visual and histologic evidence of trauma to the PIN. Conclusions Based on the findings of this study, there may be more instances of trauma to the PIN during routine wrist arthroscopy than have been previously reported. Clinical Relevance Findings suggest that transection or injury to this nerve may not lead to any clinical sequelae. However, if there is an instance where a patient has persistent, otherwise unexplained, dorsal wrist pain after a wrist arthroscopy procedure, iatrogenic neuroma of the PIN may be responsible and should be considered.