The Dorsal Intermetatarsal Approach for Plantar Plate and Lateral Collateral Ligament Repair of the Lesser Metatarsophalangeal Joints

Abstract

Category: Lesser Toes Introduction/Purpose: Access to the plantar plate has been described using either a plantar approach or an extensile dorsal approach that required complete joint destabilization and often a metatarsal osteotomy. Clinical scenarios related to plantar plate tear vary and the pathologies in early stages are frequently limited to unilateral soft tissue structures, a more focused surgical approach deemed appropriate. A novel approach requiring a release of only the lateral collateral ligament and the lateral half of the plantar plate was described and the adequacy of joint exposure was evaluated in a cadaver model. The ability to place a suture through the lateral collateral ligament and the plantar plate were analyzed and validated with pull-out strength. Methods: Nine fresh frozen cadaveric specimens were dissected in a randomized fashion across the 2nd to 4th MTP joints through the intermetatarsal space dorsally. Under distraction, soft tissue was sequentially released including dorsal capsule, lateral collateral ligament, and the lateral half of the plantar plate. Integrity of the extensor tendons, deep transverse intermetatarsal ligament, proximal attachment of the plantar plate, and osseous structures was carefully preserved. The joint exposure was quantified after each step with sizing rods. 2/o non-absorbable sutures were passed into the lateral collateral ligament and the plantar plate using a suture passer; and their pullout strength was measured using a tensiometer. Results: Progressive increase in mean of joint exposure was noted after each step of soft tissue release with the final exposure of 6mm after release of the lateral half of the plantar plate. Joint exposures after a capsulotomy and a lateral collateral release were 3mm and 4mm, respectively. Under distraction, the unilateral release of soft tissue created a lateral opening of the joint while the proximal phalangeal base adducted and medially deviated. Successful suture passage was noted in all specimens with mean pullout strength of 76 N for the lateral collateral ligament and 67 N for the plantar plate. There was a statistically significant (p < 0.01) higher suture pullout strength for the lateral collateral ligament in males when compared to female specimens Conclusion: The dorsal intermetatarsal approached appeared to be feasible for the access to the lateral collateral ligament and the lateral half of the plantar plate. The average joint exposure of 6 mm allowed a quality suture passage by a suture passer in both structures in all specimens without the need of a metatarsal osteotomy.