Accessibility of the Metatarsal Head Comparing Distraction and Plantarflexion in a 2-Portal Technique for First Metatarsophalangeal (MTP 1) Joint Arthroscopy

Abstract

Category: Arthroscopy; Midfoot/Forefoot Introduction/Purpose: Arthroscopic treatment of osteochondral lesion of the first metatarsophalangeal (MTP1) joint is an established procedure. Non-invasive distraction is most commonly applied when a dorsal 2-portal technique is used. Alternatively, plantarflexion can be utilized. In order to compare the arthroscopic reachability of the first metatarsal head, a laboratory study in anatomical specimens was performed. Methods: Twenty matched pairs (n=40) of fresh-frozen lower leg specimens were obtained and randomly assigned into two groups, a distraction (DIS) and a plantarflexion (PF) group, respectively. A standard 2-portal approach (dorsolateral and dorsomedial portals) with a 1.9mm 30° scope was used. The arthroscopic accessibility of the first metatarsal head was evaluated using chondral picks. Markings at the metatarsal heads were made intraoperatively and measured after exarticulation. Results: In the DIS group the mean accessible area was 58.03%, while the accessible area in the PF group was 55.93%. Though there is a small difference between the two groups, this difference was not statistically significant (p=0.51). Range of motion of the MTP 1 joint did not affect reachability. In one specimen (2.5%) the dorsomedial hallucal nerve was injured during arthroscopy. Conclusion: Access to the MTP1-joint for the treatment of osteochondral lesions is similar using distraction or plantarflexion during arthroscopy. The plantarflexion technique has the advantage of less surgical equipment needed. The dorsomedial hallucal nerve is at danger at the medial portal.