Polyvinyl Alcohol Hydrogel Hemiarthroplasty of the Great Toe

Abstract

Joint replacements of the first metatarsophalangeal (MTP) joint have traditionally had limited success. Joint replacements designed to date can be subdivided into hemiarthroplasties and total joint replacements. Despite ongoing requests from patients to have a joint replacement to preserve shoe wear options, many have failed to meet expectations because of loosening, implant wear, osteolysis, or loss of motion. Fusion has therefore remained the gold standard for treatment of end-stage MTP joint arthritis. A polyvinyl alcohol hydrogel implant shows promise. The Cartiva implant is a 8 or 10 mm disk of durable hydrogel material shown to resist compression and shear with exceptional wear characteristics. It is implanted with approximately 1 to 1.5 mm protrusion and acts as a spacer for the first MTP joint. This implant is commercially available in Europe and Canada. A prospective, randomized, multicenter clinical trial is underway in the United Kingdom and Canada to assess outcomes with this implant. This article outlines the indications for surgery, surgical technique, and potential complications for hemiarthroplasty of the great toe.

Prospective, Randomized, Multi-centered Clinical Trial Assessing Safety and Efficacy of a Synthetic Cartilage Implant Versus First Metatarsophalangeal Arthrodesis in Advanced Hallux Rigidus

“…The detailed surgical technique for the synthetic cartilage implant has been standardized and published previously. 17,18 A straight dorsal incision was placed centered over the medial edge of the extensor hallucis longus tendon to access to the first MTP joint. Alternatively, a standard mid-medial approach to the first MTP joint was used.…”

Association Between Patient Factors and Outcome of Synthetic Cartilage Implant Hemiarthroplasty vs First Metatarsophalangeal Joint Arthrodesis in Advanced Hallux Rigidus

“…The standardized operative technique used for the synthetic cartilage implant and postoperative protocol has been published previously. 4,24 Briefly, the first MTPJ was accessed via a straight dorsal incision, or a standard mid-medial approach (Figure 2A). The osteophytes were removed from the metatarsal head; in some cases, the osteophyte on the dorsal side of the proximal phalanx was also removed (Figure 2B).…”

“…A desire to preserve motion at the first MTPJ has prompted the development of several great toe implants, many of which demonstrated high rates of failure as a result of loosening, malalignment, dislocation, subsidence, implant fragmentation, and bone loss. 23,24…”

Hallux rigidus: a review

“…It is designed to sit proud of the metatarsal head by 1.5e2.0 mm and therefore functions as both a hemiarthroplasty and as an inter-positional spacer. 40 It has similar material properties to human articular cartilage in terms of its Young's modulus, water content and tensile strength 41 therefore making it a suitable synthetic cartilage implant.…”