[Endoprosthetic replacement of hallux rigidus]

Replacement of the first metatarsophalangeal joint (MTP1) is still controversial when compared with MTP1 fusion in treating hallux rigidus and other disabling conditions of the MTP1 joint. Prospective studies concerning endoprosthetic replacement of the MTP1 joint are not available yet. Nevertheless, better understanding of biomechanics and tribology show favour towards total endoprosthesis. Some currently available models are described (Toefit-Plus, Roto-glide, ReFlexion, Bio-Action, Moje). Furthermore the authors report their results with 30 Toefit-Plus total endoprostheses. Five complications (16.6%) included two dislocations of total prostheses and three bone fissures. In 3 of 14 cases (21%) with a 3-year follow-up, revision surgery was necessary (subluxation, persistent pain, recurrence of hallux rigidus). Of 11 cases (63%) with a 4-year follow-up, 7 revealed secondary loss of range of motion. A more aggressive postoperative treatment with early weight bearing and regular push-off of the first ray is recommended. Based on our results, MTP1 replacement should be indicated restrictively (hallux rigidus, no experiments in cases of important first ray insufficiency).