The Low Contact Stress (LCS) mobile-bearing total knee replacement (TKR) was designed to minimize polyethylene wear, aseptic loosening and osteolysis. However, registry data suggests there is a significantly greater revision rate associated with the LCS TKR.

The primary aim of this study was to assess long-term survivorship of the LCS implant. Secondary aims were to assess survival according to mechanism of failure and identify predictors of revision.

We retrospectively identified 1091 LCS TKRs that were performed between 1993 and 2006. There was incomplete data available 33 who were excluded. The mean age of the cohort was 69 (SD 9.2) years and there were 577 TKRs performed in females and 481 in males. Mean follow up was 14 years (SD 4.3).

There were 59 revisions during the study period: 14 for infection, 18 for instability, and 27 for polyethylene wear. 392 patients died during follow up. All cause survival at 10-year was 95% (95%CI 91.7–98.3) and at 15-year was 93% (95%CI 88.6–97.8). Survival at 10-years according to mechanism of failure was: infection 99% (95%CI 94–100%), instability 98% (95%CI 94–100%), and polyethylene wear 98% (95%CI92–100). Of the 27 with polyethylene wear only 19 had associated osteolysis requiring component revision, the other 8 had simple polyethylene exchanges. Cox regression analysis, adjusting for confounding variables, identified younger age was the only predictor of revision (hazard ratio 0.96, 95%CI 0.94–0.99, p=0.003).

The LCS TKR demonstrates excellent long-term survivorship with a low rate of revision for osteolysis, however the risk is increased in younger patients.

Total Hip Arthroplasty (THA) is one of the most successful and cost-effective treatments available for painful hip arthritis. Unfortunately, dislocation following primary THA is one of the most common complications, occurring in approximately 0.50–10percnt; cases. However, there is little literature that investigates the effects that dislocation has on the patient's overall function and satisfaction.

We reviewed 229 THA patients that had sustained dislocation from a prospective database, consisting 156 single dislocations and 73 with two or more. Patient outcomes were compared with a matched control group of 196 patients without dislocation in the same follow-up period. Harris Hip Score (HHS) and patient satisfaction were recorded pre-operatively and at one, five and ten years post-operatively. Mann-Whitney test compared HHS between control and dislocation groups, Chi-Square test compared patient satisfaction and implant survival.

Total HHS and functional component were significantly lower in the dislocation group at one, five and ten years (p<0.05). HHS Pain component revealed a significant difference but only at one and three years (p<0.05). Patient satisfaction only showed a significant difference at one-year review. Dislocation rates were significantly higher in females. Implant survivorship was significantly lower in the dislocation group at 15-years.

Hip-function and implant survival is significantly reduced following prosthesis dislocation, however patient satisfaction and pain levels appear unaffected at long-term follow-up.

Introduction

There is limited evidence assessing the effect of the Ankle Foot Orthosis (AFO) on gait improvements in diplegic cerebral palsy. In particular, the effect of the AFO on vertical forces during gait has not been reported. Appropriate vertical ground reaction forces are crucial in enabling children with CP to walk efficiently. This study investigated the effect of AFO application on the vertical forces in gait, particularly the second vertical peak in force (FZ2) in late stance. The force data was compared with the barefoot walk.