Polyvinyl Alcohol Hydrogel Hemiarthroplasty of First Metatarsophalangeal Joint Hallux Rigidus: Single Surgeon Five-Year Experience

Abstract

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus (HR) is the most common arthritic condition of a foot with a prevalence of up to 45% in people aged >75 years-old. First metatarsophalangeal joint (MTPJ) arthrodesis has been the historical gold standard treatment for late-stage HR. Polyvinyl alcohol (PVA) hydrogel implants have similar biomechanical properties as native cartilage, and thus have gained popularity as a joint-sparing technique that provides preservation of MTPJ motion. Initial literature demonstrated pain relief and functional outcomes equivalent to first MTPJ arthrodesis and excellent five-year survivorship. However, recent studies report variable failure rates on PVA hydrogel implants for HR. The purpose of this study was to report the five-year experience and outcomes of PVA hydrogel implants for the treatment of HR performed by a single surgeon. Methods: Electronic health records were queried from August 2016 to August 2021 for patients who underwent primary PVA hydrogel implant hemiarthroplasty (Cartiva Synthetic Cartilage Implant; Cartiva Inc, Alpharetta, GA) for symptomatic late-stage HR. All patients were treated by a single foot and ankle fellowship trained orthopaedic surgeon. A minimum of six months follow- up was required. Patient demographics and perioperative data were collected. Preoperative and postoperative range of motion, visual analog scale (VAS) pain scores, and radiographs were evaluated. Complications and the overall implant survivorship were reported. A Kaplan-Meier analysis was used to evaluate implant survival. Descriptive and univariate statistics were used to analyze data. A total of 196 primary PVA hydrogel implant procedures were performed of which 146 had a minimum six-month follow-up and were included. The mean follow-up was 14.5 (+- 11.9) months. Results: The majority of patients were female (n=103, 70.5%) with a mean age of 58.1 (+-10.1) years-old, BMI of 27.3 (+-5.2) Kg/m2, and an ASA score < 3 (n=131, 89.7%). The majority of patients had stage II or III disease (n=115, 78.8%). Patients experienced significant improvement in VAS (p<0.0001) and hallux dorsiflexion (p=0.0005) postoperatively. There was a total of 22 (15.1%) complications including implant subsidence (n=15, 10.3%), deep infection (n=6, 4.1%), and hypertrophic ossification (n=1, 0.7%). Revision surgeries were required in 12.3% (n=18) of patients at an average of 9.4 (+- 9.2) months postoperatively. This included 9 (6.2%) revision PVA hydrogel implant procedures and 9 (6.2%) first MTJP arthrodesis. The one-and two-year survival to any revision surgery (n=18) were 89.1% and 80.5%, respectively. The one- and two-year survival to MTPJ arthrodesis (n=9) were 95.9% and 86.3%, respectively (Table 1). Conclusion: In the largest single-surgeon series reported, first MTPJ hemiarthroplasty with a PVA hydrogel implant resulted in significantly improved pain and hallux dorsiflexion at an average of 15 months postoperatively. There was a high two-year survivorship of 86.3% until failure with required first MTPJ arthrodesis. Future prospective studies should be performed to refine the indications for PVA hydrogel implants and identification of risk factors for failure.