Mid-term results of the Moje Hallux MP joint replacement

There are reports of good early results in small numbers of patients implanted with the 'Moje' ceramic prosthesis. Published evidence thus far involves only small groups of patients with short-term followup. The purpose of this prospective study was to evaluate the emerging mid-term clinical and radiographic results from our center.

We describe our single-surgeon experience of 63 components in 48 patients at a mean followup of 44 months. Patient satisfaction was assessed by questionnaire and radiographic assessment performed immediately post operatively and at the latest followup.

Mean American Orthopaedic Foot and Ankle Society (AOFAS) Hallux score increased from 56 to 72 (p < 0.01) and mean satisfaction score was 7.6 (scale 1-10). Sixty-seven percent reported minimal or no pain. Five implants have been removed (8%), four because of pain associated with implant loosening and subsidence, and one because of deep infection. Fifty-seven percent of metatarsal and 56% of phalangeal components had subsided and we found radiographic evidence of loosening in 58% of X-rays analyzed at latest followup. Prosthetic subsidence was associated with greater margin of uncovered bone under the prosthesis (p = 0.05 for metatarsal, p = 0.03 for proximal phalanx component) and longer followup (p < 0.001).

In spite of the good clinical outcome at the mid-term stage with 91% implant survival, given the widespread loosening and subsidence encountered in our study, the long-term outcome following this procedure is uncertain.