Surgical Imbrication of Plantar Plate to Metatarsal Neck in the Setting of Lesser Toe Metatarsophalangeal Joint Instability

Abstract

Category:Lesser Toes; Midfoot/ForefootIntroduction/Purpose:Persistent metatarsalgia refractory to non-operative therapy with accompanying plantar plate injury represents a common and challenging treatment problem. In previous studies, radiofrequency shrinkage has been used for the treatment of MTP joint instability secondary to low-grade plantar plate lesions.1 In the shoulder, this technique shows histological evidence of modest regenerative capacity but is also associated with several chronic sequelae including capsular stretching, nerve damage, recurrent instability, adhesive capsulitis, and thermally-induced chondrolysis.2-6 The purpose of this observational study was to examine the efficacy of surgical imbrication of the plantar plate to the metatarsal neck as a novel, cost-effective approach to repair Grade 0-1 plantar plate injuries. We sought to characterize patient-reported and radiographic outcomes in patients undergoing this procedure.Methods:Patients from a single fellowship-trained orthopaedic surgeon (1/2017 - 12/2020) were screened by electronic medical record review. Inclusion criteria were age >18 years, a pre-operatively measured Patient-Reported Outcomes Measurement Information System (PROMIS) score, a Grade 0 or 1 plantar plate tear discovered at time of surgery, and repair via surgical imbrication to the metatarsal neck. PROMIS Physical Function and Pain Interference scores were obtained from 14 enrolled patients (median age was 55 years; range: 40-69; 12 female) post-operatively at 6-9 weeks, 3 months, 6 months, and 1-2 years.Basic demographic information and pertinent medical information were also obtained. Three fellowship-trained orthopaedic surgeons independently reviewed radiographs to assess reduction of the metatarsophalangeal joint, and joints were graded as reduced, subluxated, or dislocated. Wilcoxon signed-rank tests compared pre- and post-operative PROMIS scores. Changes in PROMIS scores were compared to numerical and categorical patient characteristics via univariate linear regressions and Mann- Whitney U-tests, respectively.Results:Median postoperative times to most recent PROMIS score and radiographs were respectively 13.0 months (95% confidence interval: 10.0-21.4) and 7.6 months (2.9-10.0). Median preoperative and most recent Physical Function scores were 39.5 (35-50) and 52.5 (41-62), respectively (p=0.003), and median Pain Interference scores changed from 61.0 (56-68) to 53.5 (39- 58) (p=0.002) (Fig. 1). Changes in PROMIS scores showed no association with BMI, age, preoperative opioid use, wound complications, concomitant dislocation, fibromyalgia, or mood disorder (p>0.10). Preoperatively, 9 second MTP joints were concentrically reduced, and 5 were subluxated (n=14). At 6 weeks post-operation, 13 joints remained reduced (n=14). At most recent measurement, all (n=10) joints were reduced (4 patients missing data). 9 of 14 patients underwent concomitant correction of hallux valgus at time of surgery.Conclusion:Patients with Grade 0-1 plantar plate injuries improved significantly in radiographic parameters and patient reported outcome scores following surgical imbrication of the plantar plate to the metatarsal neck. This procedure represents a novel, alternative approach that is both efficacious and cost-effective. Our work contributes valuable surgical outcomes data to a limited knowledgebase regarding pathophysiology and management for low-grade plantar plate lesions in MTP joint instability. Future work will involve larger, prospective studies to better understand outcomes of and indications for this approach.