Measuring Visualized Tendon Length in Peroneal Tendoscopy.

Background: Despite multiple studies outlining peroneal tendoscopy, no study exists to evaluate how effective tendoscopy is at visualizing the peroneal tendons without missing a lesion. We sought to measure the length of the peroneal tendons that could be visualized using tendoscopy.

Methods: Ten fresh cadaveric specimens were evaluated using standard peroneal tendoscopy techniques. Peroneus longus and brevis tendons were pierced percutaneously with Kirschner wires at the edge of what could be seen through the camera. The tendon sheaths were then dissected and the distances from anatomic landmarks were directly measured. During zone 3 peroneus longus tendoscopy, a more distal portal site was created for the final 5 specimens.

Results: The peroneus brevis could be visualized through the entirety of zone 1 and up to an average of 19.5 mm (95% confidence interval, 16.5-22.5) from its insertion onto the base of the fifth metatarsal in zone 2. Peroneus longus could be visualized through the entirety of zones 1 and 2 and up to an average of 9.7 mm from its insertion onto the base of the first metatarsal in zone 3. This distance was decreased significantly with a more distal portal. The muscle belly of peroneus brevis terminated an average of 1.8 mm (-3.7 to 7.3) above the tip of the lateral malleolus.

Conclusions: Despite limitations, these results suggest that the vast majority of the length of the peroneal tendons can be seen during routine peroneal tendoscopy. A more distal skin portal site may improve visualization of zone 3 of peroneus longus.

Clinical Relevance: This study confirms the ability of peroneal tendoscopy to see the entire tendon length with appropriate portal placement.