Introduction: Physical challenges and a long term treatment for Perthes disease can affect patients’ behaviour in their adolescence. We carried out a study to assess the long term psychosocial development of children treated non-operatively using abduction cast and brace.

Methodology: 104 patients treated for Perthes disease between 1992 and 2001 were recruited for a retrospective study. Besides clinical review, patients and their main carers were asked to fill in Strengths and Difficulties Questionnaires (SDQ). SDQ included scores for total difficulties, emotional symptoms, conduct problems, hyperactivity, peer problems, social behaviour and total impact. 70 controls, matched for age and sex, attending the clinics for other unrelated pathology were requested to fill in the same questionnaires along with their main carers.

Results: Data from 91 patients was available for assessment. Age at diagnosis was 1.9 to 7.3 years (median 3.9 years). Follow-up duration was 5.6 to 15.1 years (median 8.7 years). The age of subjects at final follow up was 8.9 to 20.4 years (median 15.3 years). The mean duration of treatment in abduction cast or brace was 2.4 years.

57 controls and 69 subjects were found to be low risk for emotional disorder (p> 0.05).

Similarly 58 control and 74 subjects were predicted to be low risk for behavioural disorder. 16 controls and 18 subjects had medium or high risk for hyperactivity or concentration disorder (p> 0.05; student t test). There was no significant difference between the self report and parent questionnaires for difficulties or their impact.

Conclusion: Perthes disease and the resultant restricted physical activities in early childhood does not affect the emotional and mental well being of patients in a long term.

To study the survival analysis of the Accord TKR and to analise the causes for its failure. 111 Accord knees were implanted in 106 patients between 1986 and 1996. All components were cemented. Eighty-seven patients were followed up and assessed according to the Knee Society Clinical Rating System.

Life table analysis of this implant using revision as the end point shows a survival of 25% at 11–12 years.

Of the 87 knees, only 31 were still in situ and of these 7 showed radiographic signs of severe loosening. However, the average knee score for these 31 was only 65/100 and average functional score was down to 42/100.

56 implants have been revised, 21 due to aseptic loosening, 11 due to gross valgus/varus instability, 9 due to deep infection, 8 due to loosening of the patella liner and 7 due to mobile bearing complications.

All 21 (24%) cases of aseptic loosening were found to have a loose femoral component; however, 56% of the total showed significant radiographic osteolysis around the stem of the tibial implants.

Retrieved implants in 5 patients showed significant delamination of the UHMWP at its margins and also revealed a track through the tibial baseplate into the medullary cavity of the tibia.

Conclusion: Early failure of this implant is due to increased debris formation from the UHMWP due to edge loading and early delamination probably as a consequence of the shape of its articulating surface. This situation was significantly aggravated by a design fault in the tibial baseplate, which encouraged unrestricted access of debris into the medullary cavity of the tibia and hence early and severe osteolysis.

A study of 50 consecutive osteoporotic pelvic rami fractures has been carried out to investigate the full extent of injury following low energy falls.

50 consecutive elderly patients with fresh fractures of the pelvis were each investigated with an MRI scan of the pelvis in order to assess the competency of the pelvic ring. The 50 patients consisted of 45 female and 5 males with a mean age of 77.7 years. 44 patients had unilateral pubic rami fractures. The mechanism of injury in all cases was a simple fall in the home environment. On admission 96% of the patients complained of sacral pain and were tender in the sacral or posterior pelvic region. On MRI, 90% of patients had a sacral fracture associated with the pubic rami fractures and in all but 4 of these the posterior pelvic pain was directly related to the sacral fracture site. At 6 month follow-up, 82% still complained of posterior pelvic tenderness. Areas of tenderness corresponded to the sites of the fractures. Before the injury, 38 of the final 44 reviewed were reasonably independently mobile, whilst at review 39 were significantly disabled.

Conclusion: The study shows that the apparently benign traumatic pelvic rami fracture in the elderly has a high association with sacral fractures. After discharge from hospital, attention should be paid to treatment of the on-going anterior and posterior pelvic pain.

The purpose of this study: is to test the hypothesis that there is little or no stress shielding afforded by a carbon composite femoral hip prosthesis when implanted in the human subject, and to investigate the possibility that a hydroxyapatite coating would prevent loosening.

The need for this development: is that loosening remains a problem for young patients who need a long term, reliable fixation of hip replacements, and it appears that if a solution exists to this problem then it probably lies away from the traditional cemented metal varieties.

One of the causes of loosening is stress shielding caused by rigid metal implants and a carbon composite femoral stem has been developed to overcome this. Paradoxically, flexible stems result in increased micro-motion at the prosthetic-bone interface and as a result they tend to loosen more frequently than metal ones. To overcome this, the carbon stem has been coated on its proximal third with hydroxyapatite, in order to get a secure fixation to the upper femur, but left bare distally to minimise weight transfer within the lower shaft.

The Study: 50 patients have entered the trial to date, and the detailed results of the first 35, which have been followed up for an average of 4 years will be presented. Stress shielding by the prosthesis was assessed, clinically, radiologically, and by dexa-scanning (usinga Hologic scanner with metal exclusion software). Two dexa-scan studies were carried out on each patient, at 1 and 2 years post operatively, and the bone mineral density of the implanted bone was compared with that of the normal contralateral side, using the Gruen zones as the basis of comparison. These results were compared with published figures for metal stems, and also with a small series of our own metal stems.

Results: 13 males and 22 females entered the trial, with an average age of 61.

Bone density around the carbon composite hip was found to increase by an average of 2% between the measurements carried out at 1 and 2 years post-op.

Conclusion: it appears that this prosthesis is fulfilling the predictions made for it, and although there is a spread of responses to it, the average patient is showing a steady increase in periprosthetic bone mineral density and is

Clinically asymptomatic. Progress to a wider trial can now be recommended.