First Metatarsophalangeal Joint Space Area Decreases Within 1 Month After Implantation of a Polyvinyl Alcohol Hydrogel Implant: A Retrospective Radiographic Case Series

Cartiva: A Review of the Best Evidence

The Cartiva implant is a synthetic polyvinyl alcohol hydrogel cartilage substitute that is used as a treatment of first metatarsophalangeal joint arthritis. The implant was designed to relieve the pain associated with hallux rigidus while preserving or restoring range of motion. A summary of outcomes, reasons for these outcomes, and technique pearls will be reviewed here. Seminal articles and current evidence are all included in this article. The aim is for the surgeon to understand all the literature, allowing the surgeon to counsel their patients appropriately, optimize patient selection and to deal with complications.

Early Failures of Polyvinyl Alcohol Hydrogel Implant for the Treatment of Hallux Rigidus

BACKGROUND

The purpose of this study was to evaluate the clinical and radiological outcomes following a polyvinyl alcohol hydrogel implant in the treatment of hallux rigidus.

METHODS

A retrospective cohort study investigating patients treated with a polyvinyl alcohol hydrogel implant for hallux rigidus was performed. Clinical outcomes were evaluated with the Foot and Ankle Outcomes Score (FAOS) and visual analog scale (VAS) score at the final follow-up. Plain radiographs were assessed postoperatively. Eleven patients (11 feet) with a mean follow-up of 20.9 months (range, 14-27 months) were included. The mean age was 60.3 years.

RESULTS

All FAOS subscales showed pre- to postoperative improvements, but there was no statistical significance in all subscales. The mean VAS score showed improvement from 4.1 to 3.0 (P = .012). On postoperative plain radiographs, implant subsidence was observed 60% (6/10) at 4 weeks after surgery and 90% (9/10) at the final follow-up. Fifty percent (5/10) showed radiologic lucency around the implant. Forty percent (4/10) had erosion of the proximal phalanx of the great toe. Four patients (36%) reported no improvement following surgery at the final follow-up, which were considered as failures. Three patients required additional surgery related to the implants. An additional patient is waiting to revise the implant.

CONCLUSION

Our current cohort study demonstrated a high failure rate with the polyvinyl alcohol hydrogel implant in patients with hallux rigidus. Significant radiologic subsidence with lysis around the implant, erosion of the proximal phalanx countersurface, and implant wear are harbingers for concern in the long term.

LEVEL OF EVIDENCE

Level IV, case series.