Nonunion Rate and Clinical Outcomes Following Percutaneous Modified Lapidus Procedure with Intramedullary Nail Fixation and Early Weightbearing

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: Minimally invasive surgery (MIS) techniques have largely focused on first metatarsal osteotomies in hallux valgus correction, but have also been used for joint preparation in foot and ankle surgery. Concurrently, new fixation methods allow early weightbearing protocols with the open Lapidus procedure, with nonunion rates comparable to those of more traditional protocols requiring prolonged nonweightbearing. We aimed to assess the nonunion rate and clinical results of a percutaneous modified Lapidus (PML) technique with axial nail fixation (Phantom Lapidus Intramedullary Nail: Paragon28, Englewood, CO USA) and early weightbearing. Methods: A retrospective chart review was performed for a consecutive series of 88 feet in 70 patients who underwent the PML technique from June 2018 to January 2023 by two fellowship-trained orthopedic foot and ankle surgeons. Indications for surgery included moderate to severe hallux valgus deformity with or without first tarsometatarsal joint (TMT) instability, first TMT arthritis, adolescent bunion, and failed prior surgery. All patients initiated weightbearing in a controlled ankle motion (CAM) boot within 12 days from surgery. Nonunion rate was defined as a symptomatic nonunion (confirmed with CT scan) that underwent revision surgery. Patients were also sent follow-up questionnaires to obtain postoperative visual analog scale (VAS) pain scores, Patient-Reported Measurement Information System (PROMIS) Physical Function scores, PROMIS Pain Interference scores, and ability to return to work. Results: Overall nonunion rate was 9.1%. All nonunions were successfully treated with nail retention, medial plate augmentation and bone grafting. There was a 15.9% all-cause reoperation rate on the 1st ray. There were 3 minor wound complications (3.4%). Average tourniquet time for the PML technique (cases performed in isolation) was 65 minutes. Survey response rate was 50%. Average follow-up time from surgery to survey response was 3.4 years (SD 1.3, range 1.2 - 5.7). VAS scores improved from 3.5 (SD 2.6) preoperatively to 0.7 (SD 1.1, range 0 – 5). Mean postoperative PROMIS Physical Function and Pain Interference scores were 56.1 (SD 6.8) and 43.6 (SD 6.6), respectively. All patients who were employed within 6 months prior to surgery were able to return to work. Conclusion: The PML technique combined with early weightbearing yields low rate of wound complications and nonunion rates comparable to historical cohorts using prolonged weightbearing protocols. For the patient, this technique additionally provides improved cosmesis and accelerated rehabilitation.