Failures of Polyvinyl Alcohol Hydrogel Implant for Hallux Rigidus and Outcomes of Revision to Arthrodesis: Mid-Term to Long-Term Results

Hallux rigidus is the most common arthritic condition of the foot, typically treated with arthrodesis. Polyvinyl alcohol (PVA) hydrogel hemiarthroplasty implant, commonly known as the brand name Cartiva, has been a mainstream alternative treatment. Failure of PVA hydrogel implant may necessitate revision to arthrodesis. This study assessed radiographic and clinical outcomes of patients who underwent arthrodesis following failed first metatarsophalangeal joint (1st MTPJ) PVA hydrogel hemiarthroplasty. A comprehensive retrospective chart review and direct patient contact were conducted for all 1st MTPJ hemiarthroplasty procedures performed with a PVA hydrogel implant between 2009 and 2021 (n = 173). For patients requiring revision to arthrodesis, time to revision, fixation method and use of bone graft or substitutes were recorded. Functional outcomes were assessed using radiographic imaging and validated scoring systems. Of the 173 PVA hydrogel implants, 16 failures and subsequent conversion to arthrodesis were included in the analysis. Four of the 16 patients (26.6%) developed symptomatic nonunion, requiring secondary revisions, resulting in no significant loss of metatarsal length. Average SF-36 PFS (short form 36 physical functioning score) was 39.5, with an FAAM-ADL (Foot and Ankle Ability Measure-activities of daily living) of 77.2 and an Foot and Ankle Ability Measure-Sports subscales (FAAM-SDL) of 59.4, and visual analogue scale (VAS) pain score was 3.2. The Kaplan-Meier analysis demonstrated a 12-year revision-free PVA hydrogel implant survival probability of 84.16%. In conclusion, PVA hydrogel implants demonstrated good mid-term to long-term survival and converting a failure to fusion did not significantly affect metatarsal length but did show higher nonunion rates and worse functional outcomes compared with primary arthrodesis.<b>Levels of Evidence:</b> Level IV.