Early Outcomes of an Anterior Ankle Fusion Plating System with rhPDGF-BB Beta Tricalcium Phosphate Graft

CATEGORY: Ankle; Ankle Arthritis INTRODUCTION/PURPOSE: Ankle fusion offers a reliable and effective treatment for end-stage ankle arthritis. Biomechanical studies have shown that plating systems may offer an advantage to ankle fusion patients with significant bone loss, bone deformity, or osteoporotic bone by providing a stiffer construct. One potential downside to plating systems is that they have been associated with soft tissue irritation due to their profile height. The objective of this case series was to assess the early patient clinical and radiographic outcomes of an anatomically designed, lower profile anterior ankle fusion plate used in combination with an autograft alternative, recombinant human protein derived growth factor (rhPDGF-BB). METHODS: All ankle fusions performed between May 2018 and August 2019 at two centers were retrospectively evaluated. All patients received an anatomically designed, low profile anterior ankle fusion plate (ORTHOLOC 3Di, Wright Medical Group, Memphis, Tennessee, USA) through an anterior surgical approach. All patients also received rhPDGF-BB as part of the surgical procedure. Patients were non-weight bearing for 6 to 8 weeks in a splint or short leg cast, before transitioning to protected partial weight bearing for another 6 to 8 weeks. Patient demographics, time to radiographic fusion, length of follow-up, and adverse events were collected as part of the review. RESULTS: There were 20 patients (12 male, 8 female) included in the analysis. The average age was 60.9 years (range, 42-90) and the average BMI was 31.6 kg/m2 (range, 21-52). There were eight diabetics, four smokers, and two patients who had preoperative ulcers. The average follow-up time was 7.8 months (range, 3-18). The fusion rate was 90%, with two nonunions. One nonunion patient was an obese, diabetic, neuropathic, smoker with a preoperative ulcer and a previous ankle fracture. She was treated with a bone stimulator and showed increased bony consolidation. The second nonunion patient was a neuropathic, diabetic who had previous hindfoot Charcot reconstruction. Her nonunion was stable and fibrous, which allowed her to ambulate pain free without bracing or assistive devices. CONCLUSION: This case series presents the first clinical results for this anatomically designed anterior ankle fusion plate. Outcomes were positive with a 90% fusion rate despite being used in a series of patients with a high incidence of risk factors and comorbidities. Additional complications were minor as related to wound healing. Further study is needed to confirm these promising initial results.