A randomised controlled clinical trial and gait analysis of fixed- and mobile-bearing total knee replacements with a five-year follow-up.

This study compared the outcome of total knee replacement (TKR) in adult patients with fixed- and mobile-bearing prostheses during the first post-operative year and at five years' follow-up, using gait parameters as a new objective measure. This double-blind randomised controlled clinical trial included 55 patients with mobile-bearing (n = 26) and fixed-bearing (n = 29) prostheses of the same design, evaluated pre-operatively and post-operatively at six weeks, three months, six months, one year and five years. Each participant undertook two walking trials of 30 m and completed the EuroQol questionnaire, Western Ontario and McMaster Universities osteoarthritis index, Knee Society score, and visual analogue scales for pain and stiffness. Gait analysis was performed using five miniature angular rate sensors mounted on the trunk (sacrum), each thigh and calf. The study population was divided into two groups according to age (≤ 70 years versus > 70 years). Improvements in most gait parameters at five years' follow-up were greater for fixed-bearing TKRs in older patients (> 70 years), and greater for mobile-bearing TKRs in younger patients (≤ 70 years). These findings should be confirmed by an extended age controlled study, as the ideal choice of prosthesis might depend on the age of the patient at the time of surgery.

[Mechanical complications of total shoulder inverted prosthesis]. / Complications mécaniques de la prothèse totale inversée de l'épaule.

Our series of inverted prosthesis included 5 patients with a mean age of 73 +/- 6 years. In 4 cases, the implant was performed as a surgical revision. The follow up was 81 +/- 15 months. Three shoulders were pain free whereas two caused a dull pain after a free interval due to mechanical complications. The mean active elevation was 72 degrees while external rotation was - 2 degrees. The adjusted Constant score passed from 32 to 60. In case of complications, the score dropped to 32. Mechanical complications were important with in one case, an unscrening of the glenosphere and in two cases, a loosening of the glenoid prosthesis. This last and major complication occurred 6 years after surgery and was promoted by the occurrence of a progressive bone erosion in the scapula. This gap represented an attempt to accomodate the medial part of the humeral prosthesis under the scapula when the arm is at rest or in adduction. The concept of an inverted prosthesis is attractive and this implant remains one of the options in cuff-tear arthropathy. Our results were not as good as those reported by others but most of ours patients had been already operated before. The occurrence of an osseous gap on pilar of scapula may lead to failure of this prosthesis. This gap remains a threath as it can progress and as such warrants a design alteration of the prosthesis.