Intermediate Outcomes of Hydrogel Implant for Hallux Rigidus

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus is the most common arthritic condition of the foot. Although a variety of great toe implants have been tried in an attempt to maintain toe motion, the majority have failed. In these cases, salvage to arthrodesis is more complicated and with a prolonged recovery. This prospective study assesses the intermediate efficacy and safety of a small (8/10 mm) hydrogel implant requiring minimal bone resection for moderate to severe hallux rigidus. Methods: Patients who underwent 1st MTP hemiarthroplasty with an organic polymer-based biomaterial implant (Cartiva), with at least five-year follow-up were contacted. Patients underwent a physical exam, and completed a pain visual analog scale (VAS) scale, SF-36, patient satisfaction questions, and the Foot and Ankle Ability Measure (FAAM). Results: Twenty-nine patients were available, with two lost to follow-up. The average time of follow-up was 5.3±0.5 years. The average age was 55.6±8.4, with 24(80%) females. The average VAS for pain improved from 64.6(±11.8) to 5.2(± 9.4) (p < 0.001). The average FAAM scores were: ADL subscale: 62.1(±16.4) to 95.8%(± 7.2) (p < 0.001); and Sports subscale: 40.2(±15.1) to 91.3%(±11.2) (p < 0.001); The average FAAM scores at follow-up for: Level of function during sports: 91.9%(±10.7); and Current level of function: 92.5%(±10.6). 69.2% of patients reported their level of function as normal, 26.9% nearly normal, and 3.8% abnormal function. Patients had 17.7 degrees of dorsiflexion, with a range of 12.7 to 22.7 degrees. Average peak dorsiflexion was 28.2°(±8.8). 92.3% stated they would undergo the procedure again. Conclusion: This study reports the mid-term results of an organic polymer-based biomaterial hemiarthroplasty implant for the management of hallux rigidus. Overall patients were very satisfied with the procedure. At an average of five years, patients are functioning very well, with limited pain and maintained motion of the 1st MTP joint. These results are promising as a viable alternative to fusion of the 1st MTP joint for management of moderate to severe hallux rigidus.