Midterm Outcomes of Polyvinyl Alcohol Hydrogel Hemiarthroplasty of the First Metatarsophalangeal Joint in Advanced Hallux Rigidus.

BACKGROUND Hallux rigidus is the most common arthritic condition of the foot. A randomized clinical trial of first metatarsophalangeal (MTP) joint hemiarthroplasty with a polyvinyl alcohol (PVA) hydrogel implant (Cartiva) demonstrated pain relief and functional outcomes equivalent to first MTP arthrodesis at 2 years postoperation, with no cases of implant fragmentation, wear, or bone loss. We prospectively determined 5-year outcomes of first MTP hemiarthroplasty with the PVA hydrogel implant. METHODS Patients who underwent first PVA hydrogel MTP hemiarthroplasty in the previously reported trial were evaluated at 5 years postoperatively. Patients underwent physical examination and radiographic evaluation and completed a pain VAS, the Short-Form-36 (SF-36), and the Foot and Ankle Ability Measure (FAAM) sports subscale and activities of daily living (ADL) subscale. At the time of this study, 29 patients had reached 5 years' follow-up. Two were lost to follow-up, leaving 27 patients with mean age 56.1 (range, 40.1-71.9) years. Mean follow-up was 5.4 (range, 4.9-6.4) years. RESULTS Postoperative active MTP natural joint dorsiflexion and peak MTP dorsiflexion were mean 18.2 (range, 10.0-30.0) and 29.7 (range, 10.0-45.0) degrees, respectively. Pain VAS, SF-36 PCS, FAAM ADL, and FAAM Sports scores demonstrated clinically and statistically significant improvements. Radiographically, no patient demonstrated changes in implant position, implant loosening or subsidence, or implant wear. One implant was removed because of persistent pain and converted to fusion 2 years postoperation. CONCLUSION Five years following first MTP hemiarthroplasty with a PVA hydrogel implant, functional outcomes improved significantly, pain was reduced significantly, and the implant demonstrated excellent survivorship. LEVEL OF EVIDENCE Level IV, prospective case series.