Early Outcomes, Revisions, and Patient Satisfaction Following Synthetic Cartilage Implant for Hallux Rigidus
Authors: Hunt Kenneth J. , Bowers Mark W. , Hamati Mary C. , Bartolomei Jonathan , Moon Daniel K. , Metzl Joshua A. 
Published: January 2022

Category: Midfoot/Forefoot; Other Introduction/Purpose: Hallux rigidus is a common condition estimated to affect 1 in 40 adults older than 60 years old. Patients experience functional limitations secondary to progressive pain and stiffness of the 1st metatarsophalangeal (MTP) joint. Historically, 1st MTP arthrodesis has been considered the gold-standard treatment for end-stage hallux rigidus. In 2016, the US Food and Drug Administration (FDA) approved the use of a synthetic cartilage implant (SCI) for the treatment of hallux rigidus grades 2-4 with an aim to improve pain and preserve range of motion at the 1st MTP joint. Studies evaluating patient satisfaction and need for reoperation have varied considerably (4-20%). We aim to evaluate outcomes, complication rate, revision rate, and overall satisfaction for patients undergoing primary SCI for hallux rigidus. Methods: In a single-institution retrospective study, we evaluated patients undergoing primary SCI for hallux rigidus between August 2016 to May 2020 by three fellowship-trained foot and ankle surgeons. Preoperatively, patient demographics, age at the time of surgery, laterality, body mass index (BMI), hallux rigidus grade, hallux valgus angle, and first-second intermetatarsal angle were collected. Operative reports were reviewed for concomitant procedures and implant size. Postoperatively, we recorded all additional treatments for continued pain or stiffness and need for revision surgery or conversion to arthrodesis. Patients were surveyed via email or telephone by an author not previously involved in their care administering patient reported outcomes (PROs): PROMIS physical function (PF), and pain interference (PI) surveys, foot and ankle SANE score, and a satisfaction survey. Results: A total of 59 feet in 56 patients underwent a primary SCI procedure for hallux rigidus. Patients were classified as grade 2 (32%), 3 (59%), or 4 (2%). Nineteen (34%) patients underwent additional procedures, and 8 (14%) had a history of prior surgery to the MTP joint. Forty-five patients (80%) completed surveys at an average of 19.5-month follow-up. The majority (58%) considered surgery a success and 42% reported being unsatisfied or very unsatisfied. Mean (+-SD) post-operative foot and ankle SANE, PROMIS PF and PI scores were 57 (+-27), 48 (+-7) and 54 (+-9), respectively. The overall revision rate was 11% (6/56) with 3 patients undergoing conversion to arthrodesis. The majority of patients (61%) stated they would undergo the procedure again. Conclusion: Consistent with existing literature, we found that the majority of patients undergoing the procedure were satisfied and would undergo the procedure again. Further, post-operative PRO scores were favorable, even when factoring in patients who were less satisfied. While our revision rate (11%) is consistent with early studies of the implant, 42% reported being unsatisfied or very unsatisfied with their procedure. These findings emphasize the importance of preoperative patient counseling regarding post- operative limitations, risks, satisfaction, and revisions rates. Further investigation into factors that may predict successful outcomes is needed to inform surgical decision-making and appropriate patient selection for this procedure.