Arthroscopic Debridement for First Metatarsophalangeal Joint Arthrodesis With a 2- Versus 3-Portal Technique: A Cadaveric Study

Abstract

To evaluate the safety and efficacy of arthroscopic debridement for arthrodesis of the first metatarsophalangeal (MTP) joint using a 2-portal technique versus a 3-portal technique. Twelve cadavers, with a mean age of 60 years, were subjected to arthroscopic debridement of the first MTP joint. Dorsolateral and dorsomedial portals were used in 6 specimens, whereas a medial portal was added in the other 6 specimens. The articular cartilage was debrided on both the proximal and distal surfaces and stabilized with a K-wire. The surrounding neurovascular structures were evaluated for injuries and measured for the distance from the portals. The fusion contact areas were estimated and denuded surfaces were measured on both sides. Results between the 2- and 3-portal techniques were compared. Statistical significance was taken as P < .05. The mean estimated fusion contact area was 180.19 mm(2) on the proximal phalanx and 180.21 mm(2) on the distal metatarsal articular surfaces. On the proximal phalanx, the percentage of denuded area was 94.71% with the 2-portal technique and 97.60% with the 3-portal technique. On the distal metatarsal, the percentage of denuded area was 93.31% with the 2-portal technique and 95.22% with the 3-portal technique. The 3-portal technique statistically increased the area of debridement on the plantar-medial surface of the distal metatarsal. The mean distance from the dorsolateral portal to the dorsolateral hallucal nerve was 3.4 mm. The mean distance from the dorsomedial portal to the dorsomedial hallucal nerve was 4 mm. The medial portal was, on average, 10.5 mm from the dorsomedial hallucal nerve and 13 mm from the plantar-medial hallucal nerve. There was no visible nerve injury detected. The 3-portal technique for arthroscopic-assisted arthrodesis of the first MTP joint allowed more complete cartilage debridement when compared with the 2-portal technique. The additional medial portal was found to be safe from the surrounding neurovascular structures. Joint preparation for arthroscopic assisted arthrodesis of the first MTP joint can be safely and effectively performed using 3-portal technique, which may reduce the risk of non-union.