MOJE TOTAL TOE REPLACEMENT

Abstract

We prospectively assessed a consecutive series of patients undergoing MTPJ arthroplasty with the MOJE prosthesis. All patients entered into the study were assessed preoperatively with the AOFAS 100-point Hallux Meta-tarsophalangeal-Interphalangeal Joint Scale and the range of motion was recorded. Patients were assessed on table postoperatively for range of motion (ROM) and then at 3, 12 and 24 months with AOFAS scores and ROM.

Forty-two toes (40 patients) were recruited into the study. There were 24 women and 16 men. The mean patient age on the day of surgery was 59 (range 37 to 73). 18 operations were carried out on the left hallux and 24 on the right. All operations were carried out for a diagnosis of hallux rigidus (although one patient also had hallux valgus, with an intermetatarsal angle of 24° and a hallux valgus angle of 40°).

The mean pre-op AOFAS score increased from 36.0 to 82.2 at 3 months (p< 0.001) and was 87.0 at 12 months and 84.2 at 24 months. There was no significant change in scores from 3 months onwards. Only 2 patients had a follow-up of 36 months; both of them had AOFAS scores of 95.

The mean arc of motion reduced from 70.8° on-table to 33.3° by 24 months (p< 0.001). The difference in arc of motion from 3 months to 12 months was a decrease from 45.6 to 40.0 which was borderline significant.

In 4 radiographs there was evidence of progressive loosening (figure 4). This was at 24 months in all 4 cases. For 3 of the patients the AOFAS score was 85. For the 4th patient the AOFAS score was 65

One patient had a spontaneous fusion of the toe. There were also three episodes of wound breakdown, one patient had intra-operative division of the EHL tendon that was repaired. We also noted post-operatively that: three feet developed Morton’s neuromata; one patient developed tarsometatarsal joint osteoarthritis of the great toe, one sesamoid osteoarthritis and one plantar fasciitis.

At the most recent follow-up appointment 33 out of 40 patients (82.5%) were satisfied with the results of their operation, 2 were dissatisfied (5%) and results regarding satisfaction were not available for 5 patients.

The results obtained in this paper demonstrate good, prospective, short-term results with the press-fit zirconium ceramic Moje implant. We believe that in the correct patient group good short term results can be achieved in the treatment of 1st MTPJ osteoarthritis as an alternative to fusion, particularly in those patients who are unwilling to have permanent stiffness in this joint for cosmetic or functional reasons