Soft-tissue arthroplasty for hallux rigidus.

Seven patients (seven feet) were evaluated at an average follow-up of 42 months following soft-tissue interposition arthroplasty of the hallux metatarsophalangeal (MTP) joint for severe hallux rigidus. The technique involved reaming of the base of the proximal phalanx and metatarsal head to decompress the first MTP joint and placement of a soft-tissue tendon bundle as a biologic spacer. Six of seven patients had bilateral disease, and a positive family history of hallux rigidus. At final follow-up, all seven patients rated their result as good or excellent, the level of pain was substantially reduced, and the mean AOFAS score substantially improved from 46 to 86 points. Mild metatarsalgia was noted by four patients and characterized by mild plantar callosities in these cases. The mean MTP dorsiflexion improved from 9 degrees to 34 degrees and patients demonstrated good to excellent plantarflexion strength on manual muscle testing and with toe rise. Physical examination of the involved feet demonstrated no evidence of pes planus, metatarsus primus elevatus, Achilles tendon contracture, or metatarsocuneiform joint hypermobility in any of the seven. The technique of soft-tissue interposition arthroplasty as described gave excellent pain relief and reliable function of the hallux, and is an alternative treatment to MTP arthrodesis in select cases of severe hallux rigidus.