Transient osteoporosis of the hip is a rare condition of unknown aetiology affecting middle aged men with no risk factors and women in their third trimester of pregnancy. The condition invariably resolves spontaneously, however, due to its rarity and initially normal plain radiographs, the syndrome is often not appreciated early in its development, and particularly represents a diagnostic problem of differentiation from osteonecrosis.

We present a case of unilateral transient osteoporosis of the hip in a 52 year old male and a case of bilateral hip involvement in a 32 year old female in her 35th week of pregnancy. Both cases include the initial and follow-up plain radiographs, MRI and DEXA scan findings, through to symptomatic resolution.

We present a literature review of the disease and analyse the current evidence on aetiology, the problems in diagnosis and the current treatment modalities.

Dual Energy X-ray absorption (DEXA) has been used to measure bone mineral density (BMD) around total hip prostheses. With the recent increase in the use of metal on metal hip resurfacing, such as the Birmingham Hip Resurfacing (BHR), there has been renewed concern over per prosthetic femoral neck fracture and implant loosening. DEXA quantitatively measures bone mineral density and therefore could predict impending loosening and fracture. To the best of our knowledge, there are no recorded studies assessing BMD around metal-on-metal hip resurfacings such as the BHR. Our intention was to produce a reliable method of measuring bone density around a metal-on-metal hip resurfacing, such as the BHR, prior to a prospective study.

We performed DEXA scans on five patients (7 BHR’s), who had undergone resurfacing with the BHR within the last two years, using the Hologic QDR 45000A scanner. Each BHR was scanned twice on the same day with complete patient repositioning between scans. We analysed the data with the Hologic prosthetic hip (v 8.26a: 3) scan analysis software (operating software 9.80D) by identifying a variable number of same-sized regions of interest (ROI) within the femoral neck. These ROI’s were derived from an inter-trochanteric line and the axis of the BHR stem in the femoral neck. Each of the 14 scans was analysed twice, by three of the authors independently; with at least one week between repeat analysis by the same observer. Statistical analysis was carried out by the local University Department of Statistics.

The variation within the same ROI in a given BHR was 0.00353, whereas the variation between all ROI’s was 1.155. The intraclass-correlation was 0.997 (i.e. the correlation between any two assessments of one ROI) with an overall coefficient of variation of 5%. The variation between the two scans for each BHR and between the three assessors was not significant (p=0.87 and p=0.42 respectively). The mean BMD of the individual ROI’s, between the two assessments of the same scans by the same assessor (i.e. intra-observer variation) was lower on the second assessment by 0.0214gcm⁻² (SD=0.0025) representing 0.5% mean density for all ROI’s. This difference was statistically significant (p< 0.001).

This method demonstrates excellent reproducibility of the method. Inter-scan and inter-observer variation was so negligible that a tiny intra-observer variation of 0.5% (of mean bone density) became statistically significant (p< 0.001), despite it making no difference to the overall intraclass-correlation. Statistical advice suggested that this very small difference in mean density (intra-observer) only reached significance due to the highly sensitive measurements and excellent reproducibility.

We have designed and demonstrated a safe, non-invasive and highly reproducible method for scanning BHR implants in vivo using DEXA. We will now use this method to prospectively study our BHR population to detect impending loosening or fracture.

The aim of this study was to demonstrate the benefits of a simple blood transfusion protocol in Primary Total Knee Replacement.

Patients undergoing TKR in the UK usually have either blood cross matched or have an auto transfusion of drained blood postoperatively. Audit of blood requirements of patients undergoing TKR showed that a large amount of blood was wasted. A CT ratio (Ratio of number of units of blood cross matched to number of units transfused) of 4.86 was obtained. Range recommended by the blood transfusion society is 2: 1 to 3: 1. A protocol was then made to Group and Save and Antibody Screen for all patients having a primary TKR, except patients with haemoglobin less than 12.5 gm/dl pre operatively and those patients with multiple red cell antibodies in their blood.

A further study involving 50 patients was carried out using the new protocol. Two units of blood was cross matched for each of 5 patients (3 with Hb < 12 gm/dl and 2 with red cell antibodies). Post operatively the 3 patients with Hb < 12 gm/dl required blood transfusion of 2 units each, reducing the CT ratio to 1.7: 1.

The benefits from above protocol are : a). Patient safety as risks of transfusion are avoided and b). Cost saving for trust on haematology technician time and on transfusion sets which cost around £70 each.

Aim: To prospectively determine the functional outcome of revision total knee replacement (TKR).

Method: We carried out a prospective outcome study recruiting 65 consecutive revision total knee replacements carried out by the senior author between 1992 and 1995. The indications for revision were aseptic loosening in 40 cases, instability in 7, infection in 4, and 16 cases for other causes. All patient was assessed preoperatively and at 3 and 12 months postop using the Nottingham Health Profile (NHP) to measure general health status. As part of this ongoing study, followup data is available for 24 patient at 5 years.

Results: There were 65 revisions in 60 patients, 5 being bilateral. There were 37 females and 23 males, with a mean age of 63 years (range 29 to 86 years). The preoperative scores showed that the patient had significant disability related to their failed TKR. Three months postop, there was a significant improvement in the NHP scores for pain and social isolation. At 12 months, the level of pain was again significantly improved over the 3 month score.

At 5 years, the pain score for the revision group deteriorated but remained better than the baseline level. This is in contrast to post primary TKR, where the improvement in pain score was maintained from 3 months onwards.

Conclusion: This study shows a significant improvement in the level of pain following revision knee arthroplasty. However, patients remain significantly disabled afterwards and do not show the very marked improvement in general health seen after primary TKR.

Aim: To prospectively determine whether social deprivation has an effect on the level of disability at presentation and the outcome from total knee replacement (TKR).

Method: A prospective outcome study was carried out between 1992 and 1996, recruiting over 2500 total knee replacements. All patients were assessed preoperatively and at 3 and 12 months postop using the Knee Society (KS) scores for clinical evaluation and the Nottingham Health Profile (NHP) to measure general health status. The Townsend Score was used as the index of social deprivation and was calculated for each patient on the basis of their address.

Results: There was no significant difference between either the Knee Society or NHP scores at baseline and the Townsend Score. This indicated that social deprivation has no effect on the level of the knee arthritis immediately prior to joint replacement, both in terms of patient disability and health status.

There was also no significant difference between either the Knee Society or NHP scores postoperatively and the Townsend Score. This indicated that social deprivation has no effect on the outcome from knee replacement.

Conclusion: This study shows that social deprivation has no significant effect on the level of disability at presentation and the outcome from total knee replacement. This is contrary to previously published reports which have shown worse outcomes in more deprived patients.