Abstract

Introduction

The aim of this study was to see if the evaluation of the initial postoperative radiograph following primary knee and hip arthroplasty correlated with clinical outcome at five years postoperatively.

Chondral injuries of the knee are extremely common and present a unique therapeutic challenge due to the poor intrinsic healing of articular cartilage. These injuries can lead to significant functional impairment. There are several treatment modalities for articular osteochondral defects, one of which is autologous chondrocyte implantation. Our study evaluates the mid to long term functional outcomes in a cohort of 828 patients who have undergone an autologous chondrocyte implantation procedure (either ACI or MACI), identifying retrospectively factors that may influence their outcome.

The influence of factors including age, sex, presence of osteoarthritis and size and site of lesion have been assessed individually and with multivariate analysis. All patients were assessed using the Bentley Functional Score, Visual Analogue Score and the Cincinnati Functional Score. Assessment were performed pre-operatively and of their status in 2010.

The longest follow-up was 12 years (range 24 to 153 months) with a mean age of 34 years at time of procedure. The mean defect size was 409 mm² (range 64 to 2075 mm²). The distribution of lesions was 51% Medial Femoral Condyle, 12.5% Lateral Femoral Condyle, 18% Patella (single facet), 5% Patella (Multifacet) and 6% Trochlea. 4% had cartilage transplant to multiple sites.

High failure rates were noted in those with previous cartilage regenerative procedures or evidence of early osteoarthritis and those with transplantation to multiple sites.

Autologous chondrocyte implantation is an effective method of decreasing pain and increasing function, however patient selection plays clear role in the success of such procedure.

Patients with osteochondrodysplasia frequently require Total Hip Arthroplasty at a younger age, as a result of early degenerative disease of the hip joint. The outcome of Modular Total Hip Arthroplasty in this group of patients has been reported previously. In this retrospective study we evaluated the outcome of custom made (CADCAM) Total Hip Arthroplasty in patients with osteochondrodysplasia.

Between 1974 and 2009, twenty one CADCAM Total Hip Arthroplasty procedures were performed in fourteen patients in our institution. There were eight female and six male patients, with the mean age at time of surgery of 40.95 years (20 to 78). The patients were followed up clinically and with the Harris hip score for a mean of 7.12 years (0.5 to 17 years).

Four of the twenty-one hips (23.8%) required revision surgery at a mean of 11.54 years (6.5 to 17 years); one required it for aseptic loosening of the femoral component; one required complete revision of the acetabular component; one required exchange of acetabular liner; and one was for symptomatic non-union of a lesser trochanter avulsion.

This study shows encouraging clinical outcomes of custom made (CADCAM) Total Hip Arthroplasty in patients with osteochondrodysplasia,

Purpose

The rate of arthroplasty or osteotomy in patients who had undergone autologous chondrocyte implantation (ACI) for osteochondral defects in the knee was determined. Furthermore, we investigated whether any radiographic evidence of osteoarthritis (OA) prior to ACI was associated with poorer outcome following surgery.

The aim of this study is to investigate whether Metal-on-Metal (MoM) implants result in more chromosome aberrations and increased blood metal ions post-operatively when compared to Metal-on-Polyethylene (MoP) implants. Metal-on-metal arthroplasties are being inserted in increasing numbers of younger patients due to the increased durability and reduced requirement 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 hybridisation (FISH). 53 patients have been recruited to date. 24 of whom had MoP prosthesis and 29 a MoM. 37 of these have had their one year follow-up with blood analysis and 14 have had 2 year follow up. Cobalt and chromium concentration increased during the first 6 months in both MoM and MoP groups, in the MoM group the chromium levels were twice that of MoP group and 12x that of the preoperative samples. Chromosome aberrations occurred in both groups. At 6 months both the MoM and MoP groups showed increase frequency of aneuploidy aberrations with further increases after one year. Structural damage in the form of translocations occurred in the MoM group after one year, but not in the MoP group, by two years there was a profound increase in translocations Preliminary results of this study show that the levels of chromium and cobalt 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.

To analyse the intra-operative variation in mechanical axes of the lower limb at various stages during navigated total knee replacement.

A prospective study was performed to analyse the intra-operative variation in the mechanical axes of the lower limb during navigated total knee replacement. All consecutive patients who underwent navigated total knee replacement were included and patients with inadequate data were excluded from the study. The intra-operative initial, trial and the final mechanical hip-knee-ankle axes were recorded from the navigation system. The differences between these axes were calculated and analysed. There were forty patients, of which 24 were females and 16 males with the age ranging from 37-89 (average 68.4) years. The right knee was replaced in 27 and the left knee in 13 patients. The average initial mechanical axes alignment was 0.03° valgus (3° varus to 3° valgus), trial alignment 0.64° varus (3° varus to 1.5° valgus) and final alignment 0.25° varus (4° varus to 4° valgus). Average deviation from initial to trial axes was 0.97°, trial to final axes was 0.74° and initial to final axes was 1.08°. The correlation co-efficient between the initial and the trial axes was 0.25, trial and final axes was 0.43 & initial and final axes was 0.09.

This study highlights a significant variation in mechanical axes between the different stages of navigated total knee replacement. The potential sources of intra-operative errors causing these changes could be soft tissue imbalance, variations in implant placement and possible tracker micro motion. Execution of bony cuts in near normal neutral alignment does not guarantee achievement of near normal final alignment. We advocate surgeons to be vigilant to avoid potential malalignment during navigated total knee replacement.