The aim of this study was to determine whether the clinical outcome of autologous chondrocyte transplantation was dependent on the timing of a high tibial osteotomy in tibio-femoral mal-aligned knees. Between 2000 and 2005, forty-eight patients underwent autologous chondrocyte implantation with HTO performed at varying times relative to the second stage autologous chondrocyte implantation procedure. 24 patients had HTO performed simultaneously with their second stage cartilage transplantation, (the HTO Simultaneous Group). 5 patients had HTO prior to their cartilage procedure, (the HTO pre-ACI Group) and 19 had HTO performed between 1 to 4 years after their second stage cartilage implantation, (the HTO post-ACI Group). There were 29 men and 19 women with a mean age of 37 years (Range 28 to 50) at the time of their second stage procedure.

With average follow-up of 72 months we have demonstrated a significant functional benefit in performing the HTO either prior to or simultaneously with the ACI procedure in the mal-aligned knee. The failure rate in the Post-ACI group was 45% compared to the Pre-ACI and Simultaneous group, with failure rates of 20% and 25%, respectively.

An HTO performed prior to or simultaneously with an autologous chondrocyte implantation procedure in the mal-aligned knee, provides a significant protective effect by reducing the failure rate by approximately 50%.

The aim of this study is to investigate whether MoM implants result in more chromosome aberrations and increased blood metal ions postoperatively whe compared to MoP implants.

MoM arthroplasties are being inserted in increasing numbers of younger patients due to the increased durability and reduced requirements for revision in these implants. Recent studies have raised many concerns over possible genotoxicity of MoM implants.

This is a prospective study of patients who have undergone elective total hip replacement, they were selected and then randomised into two groups. Group A received a MoP implant and group B received a MoM implant. Patients are reviewed pre-operatively (control group), at 3 months, 6 months, 1 year and 2 years post-operatively. On each occasion blood tests are taken to quantify metal ion levels (chromium, cobalt, titanium, nickel and vanadium) using HR-ICPMS method and chromosome aberrations in T lymphocytes using 24 colour fluorescent in situ hydridisation (FISH).

51 patients have been recruited to date, 23 of whom had MoP prosthesis and 28 a MoM. 47 of these had their 1 year follow-up with blood analysis and 38 have had 2 year follow up. There appeared to be a bedding period for both MoM and MoP groups, with an increase in metal ion release. The blood concentration of chromium, cobalt and titanium rise significantly in the MoM group at the 2 year stage. Chromosome aberrations occurred in both groups. Both the MoM and MoP groups showed increase frequency of aneuploidy aberrations and structural damage. The greatest increase in metal ion levels occurred at the 1 to 2 year interval corresponding to significant rise in chromosome aberrations.

Preliminary results of this study show that the levels of chromium, cobalt and titanium are significantly higher in the MoM group compared to the MoP group. This corresponds to increases in chromosome aberrations in the groups with increases in structural chromosome damage after two years.

Introduction

Autologous chondrocyte implantation (ACI) is contra-indicated in a joint rendered unstable by a ruptured anterior cruciate ligament (ACL). We present our experience of ACI repair with ACL reconstruction