Osteoarthritis is a common condition in which the surface of the joint becomes worn, and the adjacent bone thickens and forms osteophytes. It can affect the first metatarsophalangeal joint at the base of the big toe, which may become painful and stiff (hallux rigidus).
Conservative treatments include exercise, physiotherapy, orthotics, analgesics, non-steroidal anti-inflammatory tablets and cream, and corticosteroid injections into the joint. Surgery may be needed if severe osteoarthritis of the first metatarsophalangeal joint does not respond to conservative treatments. If an osteophyte on the surface of the joint is the only problem, it can be trimmed (cheilectomy). The main surgical options for treating the whole joint are fusion (arthrodesis), osteotomy or joint replacement. Rarely, excision arthroplasty is offered.
Synthetic cartilage implant insertion for hallux rigidus is usually done under general or regional anaesthesia. A moulded cylindrical implant made of polyvinyl alcohol (a soft plastic-like substance) and saline is used with specifically designed single-use instruments. A small incision is made over the top of the big toe joint, and a drill is used to remove enough bone to make an appropriately sized hole for the implant. The implant is placed into the hole in the bone and left slightly raised, providing a smooth and slippery surface in the area of the cartilage defect. Once the implant is in place, the incision is closed with sutures. Weight bearing can typically resume immediately after the procedure. The aim is to reduce pain and improve the toe's range of motion.