Review Question - QID 3832

This patient presents with numbness in the innervating distribution of superficial peroneal nerve (SPN). SPN is most at risk of injury with use of the anterolateral portal, shown as Portal 3.

Neurological injury is the most common complication associated with ankle arthroscopy. The rate of injury varies in the literature from 3.5-10%. The SPN crosses the fibula (from lateral compartment to anterior compartment) on average 11cm (range 3-15cm) proximal to the tip of the lateral malleolus. It then divides into its terminal branches, including the medial dorsal cutaneous nerve (MDCN) to the great toe and intermediate dorsal cutaneous nerve (IDCN) to the dorsum of the foot.

Ferkel et al. reviewed the complications associated with ankle arthroscopy and discuss strategies to prevent them. They again state that the overall complication rate is 9%. They report most complications associated with foot and ankle arthroscopy are transient and tend to resolve within 6 months.

Young et al. reviewed the complications of ankle arthroscopy. An overall complication rate of 6.8% was observed. 16/20 complications were neurologic - six of these were related to the anterolateral portal, and eight patients had dysesthesias involving the dorsal part of the midfoot.

Urguden et al. retrospectively reviewed 41 patients who underwent operative arthroscopy for anterolateral impingement of the ankle. They describe 3 classic intra-articular soft tissue pathologies causing impingement. These include: scar tissue of the synovium, meniscoid lesion associated with localized synovitis, and scar formation due to distal fascicle of the AITFL or tear of the AITFL.

Illustration A shows the described 'fourth toe flexion sign'. This is used to help define the course of the superficial peroneal nerve as it across the ankle joint and foot. Illustration B shows the classic anterior portals used in ankle arthroscopy.

Incorrect Answers:
Answer A: Injury to the peroneal neuorvascular bundle (deep peroneal nerve and anterior tibial artery) can occur with Portal 1 (mid-ankle portal)
Answer B: Injury to the sapheneous nerve can occur with Portal 2 (anteromedial portal)
Answer D: Portal 4 is not classically described.
Answer E: Injury to the sural nerve can occur with Portal 5 (posterolateral portal)