Revision total hip replacement is a procedure often associated with significant blood loss and subsequent transfusion. Intra-operative cell salvage is one approach to minimising this problem.

We carried out a retrospective study of 134 consecutive revision total hip carried out by one surgeon between June 2003 and September 2006 in the Southern General Hospital, Glasgow, 134 replacements (excluding those performed in the presence of active infection where cell salvage is contra-indicated).

In Group A (56 patients), operated upon after October 2005, Intra-operative cell salvage was routinely used. In Group B (78 patients), operated upon before October 2005, Intra-operative cell salvage was not used.

Data was collected on transfusion of salvaged blood, transfusion of allogenic blood, operation type, indication for surgery, complications and length of hospital stay.

In Group A, an average of 1.52 units of allogenic blood was transfused per case, compared with an average of 3.35 units in Group B (p=0.01), a reduction of 55%.

In Group A 50% of patients received allogenic blood transfusion, compared with 68% of patients in Group B, a relative reduction of 26% (0.1> p> 0.05).

There was no difference between the two groups regarding haemoglobin drop and length of hospital stay. Data regarding complications yielded no significant results due to small cohort size.

Further Breakdown of data by operation type and indication did not yield significant results due to the small cohort size.

Our results show that routine use of intra-operative cell salvage in revision total hip replacement leads to a significant reduction in allogenic blood transfusion with subsequent implications upon cost, resource management, and patient safety.

Introduction: Metal on Metal articulations produce Cobalt Chromium nanoparticles (CoCrNP) which seems to affect the adaptive immune system, as evident from the perivascular infiltrate of lymphocytes & plasma cells found around some implants, and the reduced CD8+ count described with hip resurfacing. We therefore analyzed effects of CoCrNP on Dendritic Cells, T cells & B cells.

Methods: CoCrNP were produced by repetitive short spark discharges between electrodes of prosthetic CoCr alloy. Electron micrography & BET both confirmed nanoparticle size.

Dendritic Cells were cultured from mouse bone marrow and incubated with CoCrNP of varying concentrations, for 24hrs, or lipopolysaccharide as a positive control. Activation status was then characterized by CD40 expression on FACS analysis.

Results: CoCrNP did not significantly increase CD 40 expression on DCs or Cd 40/ Cd 86 expression on B cells. At subletal concentrations, CoCrNP inhibited ∝CD3 & ∝CD28 dependent T-cell proliferation.

Discussion: CoCrNP reduces both signal 1 & signal 2 dependent T cell proliferation, which may explain the observed reduction in CD 8+ count with hip resurfacing.

Introduction: Acetabular introducers have an inbuilt inclination of 45 degrees to the shaft. With the patient in the lateral position the operator aims to align the introducer shaft to vertical to implant the acetabulum at 45 degrees. We examined if a bulls-eye spirit level attached to an introducer improved the accuracy of implantation.

Methods: A small circular bulls-eye spirit level was attached to the handle of an acetabular introducer directly over the shaft. A sawbone hemipelvis was fixed to a horizontal, flat surface. A cement substitute was placed in the acetabulum and subjects asked to implant a polyethylene cup into the acetabulum, aiming to obtain an angle of inclination of 45 degrees. Two attempts were made with the spirit level dial masked and two attempts made with it unmasked. The distance of the air bubble from the spirit level’s centre was recorded by a single assessor. The angle of inclination of the acetabular component was then calculated. Subjects included a city hospital’s Orthopaedic consultants and trainees.

Results: Eighteen subjects completed the study, with no significant difference in performance between consultants and trainees. Accuracy of acetabular implantation when using the unmasked spirit-level improved significantly in all grades of surgeon. With the spirit level masked, 11 out of 36 attempts were accurate at 45 degrees, 19 attempts ‘closed’ (< 45degrees) and 6 were ‘open’ (> 45 degrees). With the spirit level visible, all subjects achieved an inclination angle of exactly 45 degrees on both attempts. The mean difference between masked and unmasked implantation angle was 0.94 degrees (95% CI 0.64 to 1.24, p< 0.0001).

Discussion: A simple device attached to the handle of an acetabular introducer can significantly improve the accuracy of implantation of a cemented cup into a saw-bone pelvis in the lateral position. This technique may be easily transferable into an in-vivo study

Introduction: Instability after total hip arthroplasty is an important complication. It commonly occurs in the immediate postoperative period, but the risk is reported to continue over time. There are numerous surgical treatment options, but they have relatively unpredictable outcomes. Numerous factors have been associated with dislocation, but research has mainly focused on surgical factors. Epidemiological factors remain the subject of much debate. We aimed to establish the incidence of dislocation over time.

Methods: The Scottish National arthroplasty non-voluntary registry is based on SMR01 records (Scottish Morbidity Record) data. We analyzed the Scottish National Arthroplasty Project to find patients’ dislocation rates up to 12 years post surgery.

Results: There were 62,175 total hip arthroplasties performed from April 1989 to March 2004 with an annual incidence of dislocation of 0.9%. The majority of dislocations occur by 12 months (66%) but patients remain at relatively high risk even after the first 3 months by when only 23% of the total have occurred. We found no increase in the rate of dislocation after 2 years.

Discussion: Patients should be warned that the risk of dislocation remains for the first year. However, it appears there is no late increase in dislocation rate associated with wear and declining mental or muscle function.

Introduction: This study is a prospective series using a porous-coated cobalt-chromium alloy cup augmented with screw fixation for acetabular revisions.

Methods: Between August 1997 and December 2001, eighty-five consecutive cementless acetabular revisions (81 patients) were performed. The mean age at operation was 64 years. Using the AAOS classification of acetabular defects there was one type I defect, 25 type two defects and 59 type III defects. Eighty-three cases were available for review (98%) with an average follow up of 6 years 6 months (range 3 months – 110 months). Clinical outcome was measured using the Charnley Hip Score and radiological assessment by plain radiographic measurement.

Results: The Charnley Hip Score had improved from a pre-operative average of 7.52 (range 4–11) to the latest score of 14.84 (range 8 – 18). Significant cup migration occurred in only one case, which did not require revision. Sixteen cases demonstrated non-progressive radiolucent lines in one or two Delee and Charnley zones but none extended to all three zones. There were no cases of significant osteolysis. There were five dislocations none requiring re-operation; one revision was carried out for deep infection and one liner exchange at time of stem revision for subsidence. The results of Kaplan-Meier survival analysis using revision for all causes as the endpoint was 98.8% (95% confidence limits 0.964 to 1) at seventy-three months.

Discussion: This press fit porous-coated cobalt-chromium alloy cup augmented with screw fixation for acetabular revision surgery produced excellent midterm results. Changes in cup design and material should only be undertaken with consideration of such results.

Introduction: Instability after total hip arthroplasty is an important complication. Instability usually occurs in the immediate postoperative period, but the risk also increases with time. There are numerous surgical treatment options, but they have relatively unpredictable outcomes. Numerous factors are associated with dislocation, but research has mainly focused on surgical factors. Epidemiological factors remain the subject of much debate. The aim of this study was to find any such factors significantly associated with dislocation.

Methods: The Scottish National arthroplasty non-voluntary registry is based on SMR01 records (Scottish Morbidity Record) data. We analyzed the Scottish National Arthroplasty Project to find patients’ dislocation rates up to 1 year postoperatively for age, surgeon volume, gender, previous surgery, diagnosis, and follow-up duration.

Results: There were 14,314 total hip arthroplasties performed from April 1996 to March 2004. Two hundred sixty-six dislocations occurred for an average annual incidence of 1.9%. There was an association between rate of dislocation with age, surgical volume, and previous fracture. However, there was no increase in the rate of dislocation associated with gender or with diagnoses of stroke or Parkinson’s disease.

Discussion: Statistical analysis of large databases allows identification of the most relevant factors. There is a surprisingly low incidence of THA dislocation in patients with neurological conditions. This epidemiological data allows prognostic assessment of the risk of dislocation for individual patients. From this strategies can be employed to reduce the chance of dislocation in high-risk patients.

We compared peri-prosthetic bone mineral density between identical cemented and cementless LCS rotating platform total knee arthroplasties. Two matched cohorts had dual energy x-ray absorptiometry scans two years post-operatively using a modified validated densitometric analysis protocol, to assess peri-prosthetic bone mineral density. The knee that was not operated on was also scanned to enable the calculation of a relative bone mineral density difference. Oxford Knee and American Knee Society scores were comparable in the two cohorts.

Statistical analysis revealed no significant difference in absolute, or relative peri-prosthetic bone mineral density with respect to the method of fixation. However, the femoral peri-prosthetic bone mineral density and relative bone mineral density difference were significantly decreased, irrespective of the method of fixation, particularly in the anterior distal portion of the femur, with a mean reduction in relative bone mineral density difference of 27%.

There was no difference in clinical outcome between the cemented and cementless LCS total knee arthroplasty. However, both produce stress-shielding around the femoral implants. This leads us to question the use of more expensive cementless total knee components.

Revision of a total knee arthroplasty may require an extensile approach to permit a satisfactory exposure without compromising the attachment of the patellar tendon. It has been assumed that a rectus snip is a relatively benign form of release, but the effect of using this approach on function, pain and patient satisfaction is not known.

From January 1997 to December 1999, 107 patients who underwent revision of total knee arthroplasty were followed up at a minimum of two years (mean 40.5 months) and assessed by the Oxford Hip Score, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Short-Form (SF)-12 and patient satisfaction. Co-morbidity, surgical exposure, the Hospital for Special Surgery (HSS) knee scores and the range of movement were also used. A standard medial parapatellar approach was used in 57 patients and the rectus snip in 50. The two groups were equivalent for age, sex and co-morbidity scores. The WOMAC function, pain, stiffness and satisfaction scores demonstrated no statistical difference. The use of a rectus snip as an extensile procedure has no effect on outcome.

Dupuytren’s disease is a chronic inflammatory process which produces contractures of the fingers. The nodules present in Dupuytren’s tissue contain inflammatory cells, mainly lymphocytes and macrophages. These express a common integrin known as VLA4. The corresponding binding ligands to VLA4 are vascular cell adhesion molecule-1 (VCAM-1) present on the endothelial cells and the CS1 sequence of the fibronectin present in the extracellular matrix. Transforming growth factor-beta (TGF-ß) is a peptide hormone which has a crucial role in the process of fibrosis.

We studied tissue from 20 patients with Dupuytren’s disease, four samples of normal palmar fascia from patients undergoing carpal tunnel decompression and tissue from ten patients who had received perinodular injections of depomedrone into the palm five days before operation. The distribution of VLA4, VCAM-1, CS1 fibronectin and TGF-ß was shown by immunohistochemistry using an alkaline phosphorylase method for light microscopy.

In untreated Dupuytren’s tissue CS1 fibronectin stained positively around the endothelial cells of blood vessels and also around the surrounding myofibroblasts, principally at the periphery of many of the active areas of the Dupuytren’s nodule. VCAM-1 stained very positively for the endothelial cells of blood vessels surrounding and penetrating the areas of high nodular activity. VCAM-1 was more rarely expressed outside the blood vessels. VLA4 was expressed by inflammatory cells principally in and around the blood vessels expressing VCAM-1 and CS1 but also on some cells spreading into the nodule. TGF-ß stained positively around the inflammatory cells principally at the perivascular periphery of nodules. These cells often showed VLA4 expression and co-localised with areas of strong production of CS1 fibronectin.

Normal palmar fascia contained only scanty amounts of CS1 fibronectin, almost no VCAM-1 and only an occasional cell staining positively for VLA4 or TGF-ß.

In the steroid-treated group, VCAM-1 expression was downregulated in the endothelium of perinodular blood vessels and only occasional inflammatory cell expression remained. Expression of CS1 fibronectin was also much reduced but still occurred in the blood vessels and around the myofibroblast stroma. VLA4-expressing cells were also reduced in numbers. A similar but reduced distribution of production of TGF-ß was also noted.

Our findings show that adherence of inflammatory cells to the endothelial wall and the extravasation into the periphery of the nodule may be affected by steroids, which reduce expression of VCAM-1 in vivo. This indicates that therapeutic intervention to prevent the recommencement of the chronic inflammatory process and subsequent fibrosis necessitating further surgery may be possible.