Contact Characteristics of Metatarsophalangeal Joint Osteochondral Defect Repairs Following a Novel Hybrid Procedure With a Subchondral Implant and Dermal Allograft.

Background: The purpose of this study was to quantify metatarsophalangeal (MTP) joint contact characteristics before and after reconstruction of osteochondral defects using a novel hybrid procedure.

Methods: The MTP joint contact areas, mean contact pressures, and peak contact pressures were measured using Tekscan pressure sensors with 50, 100, and 150-N compressive loads. Five conditions were tested: intact, 8-mm osteochondral defect, 8-mm repair, 10-mm defect, and 10-mm repair. Defects were created at the center and perpendicular to the metatarsal head by drilling. Defects were repaired with titanium fenestrated threaded implants countersunk in the subchondral bone. An acellular dermal allograft was placed and made flush with the surface of the metatarsal head.

Results: Repair of the 8-mm defect significantly increased MTP joint contact area by 24.1 ± 3.2 mm2 and significantly decreased contact pressure at all compressive loads by 97.9 ± 12.1 kPa compared with the defect condition. Repair of the 8-mm defect also significantly decreased peak contact pressure compared with the intact condition at 100 and 150 N an average of 510.6 ± 215.5 kPa (P < .041). Repair of the 10-mm defect significantly increased contact area at 100 and 150 N by 42.0 ± 8.3 mm2 (P < .001) and significantly decreased contact pressures at all compressive loads by 214.5 ± 30.7 kPa compared with the defect (P < .003).

Conclusions: The MTP joint contact areas, contact pressures, and peak pressures were restored to intact conditions and contact pressures decreased following reconstruction of both 8- and 10-mm osteochondral defects using subchondral implants with dermal allografts.