Prospective evaluation of protocol for surgical treatment of lesser MTP joint plantar plate tears

Abstract

Background: Instability of the lesser metatarsophalangeal (MTP) joints is a common cause of deformity and pain. The purpose of this study was to prospectively evaluate the surgical outcomes for the different grades of plantar plate tears and propose a treatment protocol.

Methods: Sixty-eight patients (100 MTP joints) were prospectively enrolled and graded according to the anatomical grade system for plantar plate tears. Based on this classification, the appropriate surgical procedure was chosen as follows: grades 0 and I, thermal shrinkage with radiofrequency; grades II and III, direct reinsertion of the plantar plate; and grade IV, flexor-to-extensor tendon transfer. All surgical procedures were associated with a Weil metatarsal osteotomy. Evaluations were performed before and after surgical treatment with a mean follow-up of 2 years (12-36 months), using clinical and radiological parameters: American Orthopaedic Foot and Ankle Society (AOFAS) Lesser MTP-IF Scale, visual analog scale (VAS), ground touch, joint stability, and toe purchase.

Results: The analysis of the clinical parameters demonstrated a significant improvement of all groups (P < .0001) after surgical treatment, but grade IV had less VAS improvement and a fair AOFAS average score (72 points). All groups improved regarding physical examination parameters, but grade I, III, and IV tears had proportionally less stable MTP joints following surgery, as well as a lower proportion of normal postoperative toe purchase and ground touch. All groups showed a significant improvement regarding radiographic parameters.

Conclusion: All groups of operatively treated patients had significant improvement with regard to subjective and objective parameters. Grades I, III, and IV presented inferior results compared with grades 0 and II.

Level of evidence: Level IV, case series.

Keywords: MTP plantar plate repair; MTP plantar plate tears; Weil metatarsal osteotomy; lesser toe dislocation; metatarsalgia; metatarsophalangeal joint instability.