Mid-term results of the Moje Hallux MP joint replacement.

BACKGROUND: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.

Incidence of periprosthetic fractures after hip hemiarthroplasty: Are uncemented prostheses unsafe?

Displaced intracapsular fractures of the neck of femur are routinely treated in the elderly with either cemented or uncemented hemiarthroplasty. Recent evidence suggests a superior outcome with the use of cement, but uncemented prostheses are still employed for those with multiple co-morbidities or particular frailty. In Scotland, the Scottish Intercollegiate Guidelines Network (SIGN) recommendations are used to identify which patients should receive a cemented prosthesis. These are simply based upon the presence of cardiorespiratory disease, particularly in the frail elderly patient. Between January 2007 and June 2010, a total of 1397 patients with neck-of-femur fractures presented to our unit. Retrospective analysis was performed with particular attention given to the rate of postoperative periprosthetic fracture. As many as 546 fractures were treated with hemiarthroplasty, of which 183 were treated with a cemented Exeter Trauma Stem (ETS) and 363 were treated with an uncemented Austin-Moore prosthesis (AMP). At the time of our retrospective analysis, we found that 15 (4%) patients treated with an uncemented prosthesis went on to sustain a periprosthetic fracture. There were no periprosthetic fractures in the cemented group (p=0.004). Data analysis by case-note review of those patients sustaining a periprosthetic fracture was then performed. Seven (50%) suffered from confusion secondary to dementia, six (43%) had a history of significant cardiac disease (recent myocardial infarction (MI) or cardiac failure) and two (14%) had known renal impairment. The mean time to fracture after uncemented hemiarthroplasty was 2 years. The majority (80%) were fractures which required further surgery. Revision surgery in these patients was associated with an overall complication rate of 42% (mainly deep infection and haemorrhage requiring transfusion). Two of the patients had a fracture that could be treated conservatively. It is concluded that, in conjunction with the treating senior anaesthetist, cemented implants should be considered in all patients, especially those who are deemed to be frail and with multiple co-morbidities. A periprosthetic fracture rate of 14% at a mean of 2 years after uncemented hemiarthroplasty represents a potentially unacceptable risk for such a frail population. In particular, we feel that the AMP should not be used for treating displaced intracapsular neck-of-femur fractures.

Uncemented ceramic-on-ceramic THA in adults with osteonecrosis of the femoral head.

Advanced osteonecrosis of the femoral head is increasingly treated with uncemented total hip arthroplasty (THA), particularly in the younger population. While early outcomes appear promising, little is known about the optimum bearing surface in this patient subpopulation. The goal of this study was to evaluate the clinical and radiological outcomes of uncemented ceramic-on-ceramic THA in young adults with osteonecrosis of the femoral head. Twenty-four consecutive patients (24 hips) with osteonecrosis of the femoral head and 24 patients (24 hips) with osteoarthritis were treated with an uncemented ceramic-on-ceramic THA. Mean patient age for the osteonecrosis group was 46 years and for the osteoarthritis group was 50 years. At a mean follow-up of 34 months, functional improvement was significant in both groups (P<.01). The outcome was good to excellent for 85% of patients (17 hips) in the osteonecrosis group and 90% of patients (19 hips) in the osteoarthritis group. Harris and Oxford Hip scores were significantly better (P<.05) in the osteoarthritis group than in the osteonecrosis group at 6 months postoperatively but at no other assessment visit. Our results suggest that ceramic-on-ceramic THA in osteonecrotic patients produces similar clinical and radiological outcomes to those with osteoarthritis at a minimum 24-month follow-up. Ceramic-on-ceramic uncemented THA is therefore a useful adjunct for the treatment of advanced osteonecrosis of the femoral head.