Arthroscopic accessibility of the first metatarsophalangeal joint for osteochondral defects of the metatarsal head by two-portal technique - comparing joint distraction and plantarflexion.

Background: Several techniques and approaches for first metatarsophalangeal (MTP1) joint arthroscopy have been reported, where joint accessibility plays a key role. This study aimed to evaluate differences in arthroscopic accessibility of the first metatarsal head (MTH1) comparing non-invasive distraction and maximum plantarflexion in a two-portal approach.

Methods: Forty fresh-frozen lower leg specimens were included and divided into a distraction group (D-group) and a plantarflexion group (PF-group). A two-portal technique (1.9 mm-30°-scope) was used for arthroscopy, maximum reach at the MTH1 was marked. Following arthroscopy, specimens were dissected and examined for iatrogenic injuries. The reached area at the chondral surface was pinned and accessibility calculated.

Results: Accessibility of the MTH1 was 58.03 % ± 13.64 (D-group) and 55.93 % ± 10.30 (PF-group, p = 0.51). The dorsomedial hallucal nerve was injured in one specimen (2.5 %).

Conclusion: Maximum plantarflexion showed no difference in arthroscopic MTP1 joint accessibility compared to non-invasive distraction in a two-portal approach. During dorsomedial portal placement, the dorsomedial hallucal nerve is at risk for iatrogenic injury.