Background: Chronic prosthetic joint infection is a cause of patient morbidity and can be challenging to treat. Surgeons performing revision arthroplasty of the hip and knee are confronted with a growing number of patients with extensive loss of bone stock. The use of a modular endoprosthesis is a possible method of treatment in such patients.

Aim: The purpose of this study was to assess the functional outcomes and the success of a single and two stage revision procedure in eradicating chronic prosthetic joint infection using a femoral endoprosthesis.

Methods: A prospective database was reviewed of 20 patients who underwent a proximal, total or distal femoral endoprosthetic replacement after chronic prosthetic infection. Radiographs performed at the time of latest follow up were evaluated for signs of loosening, osteomyelitis and implant failure. The functional status was assessed using the Short Form (SF)-36 health survey score, Toronto extremity salvage score (TESS) and the Enneking score.

Results: Thirteen patients underwent a single stage revision procedure and seven had been treated with a staged revision. At the latest follow up none of the 13 patients treated with a single stage procedure had evidence of ongoing infection. Of the seven patients who had a staged revision, 3 patients had evidence of ongoing infection. The mean pre operative Enneking score for the entire group was 17.1 points and this improved to 47.5 points post operatively (p< 0.0002). The mean pre operative TESS score for the entire group was 42% and this improved to 59% post operatively (p< 0.005). There was also a statistically significant improvement in all of the components of the SF-36 score.

Conclusion: We believe that the use of a modular endo-prosthesis in the treatment of chronic prosthetic joint infection is a successful and viable option in eradicating infection, preserving the limb and providing a good functional result.

Aims: There are concerns over the physiological effects of intramedullary femoral fracture stabilisation in patients with pulmonary injury. This large animal study used invasive monitoring to obtain sensitive cardiopulmonary measurements and compared the responses of ‘Early Total Care’ (intramedullary fracture fixation) and ‘Damage Control’ (external fixation), after the induction of lung injury.

Methods: Acute lung injury (PaO2/FiO2 < 200 mmHg) was induced in 12 invasively monitored and terminally anaesthetised sheep via oleic acid infusion into the right atrium. Each animal underwent surgical femoral osteotomy and fixation with either reamed intramedullary (n=6) or external fixation (n=6). Haemodynamic and arterial blood-gas measurements were recorded at baseline, 5, 30 and 60 minutes after fracture stabilisation.

Results: The mean (+/− S.E.) PaO2/FiO2 fell significantly (p< 0.05) from 401 (+/− 39) to 103 (+/− 35) and 425 (+/− 27) to 122 (+/− 21) in the externally fixated and intramedullary nailed groups respectively after acute lung injury. The further combined effect of surgical osteotomy and fracture fixation produced a mean (+/− S.E.) PaO2/FiO2 of 98 (+/− 21) and 114 (+/− 18), in the externally fixated and intramedullary nailed groups immediately after surgery. This was not significantly different within or between groups. Similarly the pulmonary vascular resistance (PVR) measured at 5.8 (+/− 0.8) and 4.8 (+/− 0.7) after lung injury in the externally fixated and intramedullary nailed groups changed to 5.7 (+/− 0.5) and 4.0 (+/− 0.7) after surgical osteotomy and fracture fixation (no significant difference within or between groups). The PaO2/FiO2 or PVR was not significantly different at the monitored 5, 30 and 60 minute intervals after fracture stabilisation.

Conclusion: Against a background of standardised acute lung injury, there was no further deterioration produced by the method of isolated femoral fracture fixation in sensitive physiological parameters commonly used during intensive care monitoring.

There is little evidence describing the influence of body mass index on the outcome of Total Hip Replacement (THR). There are concerns that an increasing BMI may lead to increased blood loss, infection and venous thromboembolism. 800 consecutive patients undergoing primary cemented THR were followed for a minimum of 18 months. The Harris Hip Score (HHS) and SF-36 were recorded pre-operatively and at 6 and 18 months post-operatively. In addition other significant events were noted, namely death, dislocation, re-operation, superficial and deep infection and blood loss. Multiple regression analysis was performed to identify whether BMI was an independently significant predictor of the outcome of THR.

No relationship was seen between the BMI of an individual and the development of any of the complications noted. The HHS was seen to increase dramatically post-operatively in all patients. BMI did predict for a lower HHS at 6 and 18 months, and a lower physical functioning component of the SF-36 at 18 months. This effect was small when compared with the overall improvements in these scores.

Conclusion: THR provides good symptomatic relief irrespective of BMI. On the basis of this study we can find no justification for withholding THR solely on the grounds of BMI.

Background: Transcranial Doppler Ultrasound has been used to detect cerebral micremboli following long bone fractures and intramedullary stabilization. However the clinical effects in terms of cognitive function remain unclear. We aim to measure the cerebral embolic load and to clarify clinical cognitive function following lower limb long bone fractures stabilised by reamed intramedullary fixation.

Methods: 27 femoral and tibial diaphyseal fractures (median age 36 years) were cognitively assessed 3 days following surgery and compared to the normal age and intelligence matched population. A wide range of cognitive tests assessed: global cognitive function; verbal fluency and speed; immediate and delayed memory recall; attention and mental processing speeds. 20 patients had intra-operative transcranial Doppler ultrasound monitoring of the middle cerebral artery for embolic signals. In addition a marker of neuronal injury (S-100B protein) was measured pre-operatively and at 0, 24 and 48 hours following surgery. One sample Wilcoxon signed rank test compared median (percentile) cognitive scores for the fracture patient cohort to a value of 50 representing the normal population.

Results: A significant deterioration in immediate memory recall of unstructured material was noted following surgery. Using established criteria, 4 patients had detectable cerebral emboli with a median count of 3 (range 2–9). Scatter plot graphs indicated no correlation between cerebral embolic events and clinical cognitive dysfunction. S-100B protein levels increased from a pre-operative median (interquartile range) of 0.20 (0.23) to a peak immediately following surgery of 0.51 (0.97) with no correlation to clinical cognitive dysfunction

Conclusions: A small number of cerebral embolic events occur during intramedullary fracture stabilisation but with no direct correlation made to cognitive dysfunction on detailed testing. Recent concerns over the specificity of S100B protein due to extracerebral tissue release appear to be confirmed.

Significance: Clarify cognitive function following intramedullary fracture stabilisation and correlate with cerebral (systemic) embolic load.

Introduction: The water soluble vitamins B1, B2 and B6 are essential precursors for a wide variety of coenzymes involved in intermediary metabolism. Recent evidence suggests that the systemic inflammatory response associated with disease, injury and infection may lower micronutrient concentrations in plasma independent of tissue stores. Elective knee arthroplasty surgery has been shown to induce a significant and reproducible systemic inflammatory response and therefore provides an ideal model with which to examine the relationship between plasma and erythrocyte (intracellular) concentrations of B-vitamins and the evolution of the systemic inflammatory response.

Methods: The study was approved by the local ethics committee. All subjects were informed of the purpose and procedure of the study and all gave consent. Venous blood samples (EDTA) were withdrawn pre-operatively from 12 primary knee arthroplasty patients and at 12, 24, 48, 72 and 168 hours after the start of surgery. Analysis of plasma and red cell vitamins B1, B2, B6, C-reactive protein and albumin. Data presented as median and range. Data from different time periods were tested for statistical significance using the Freidman test and where appropriate comparisons of data from different time periods were carried out using the Wilcoxon signed rank test.

Results: All patients were over the age of 60 years and had circulating concentrations of B vitamins in the normal range (B1 275–675ng TDP/g Hb; B2 220–410nmol/l; B6 17–135nmol/l). On analysis of serial postoperative values over the study period 0–168hrs there were significant increases in C-reactive protein and significant decreases in albumin concentrations peaking/troughing at 48hrs returning towards normal concentrations at 7 days (p< 0.001). In contrast, during this period plasma albumin (p< 0.001), B2 (p< 0.001) and B6 (p< 0.001) concentrations fell transiently by as much as 50% returning towards normal in parallel with the fall in C-reactive protein concentrations. In contrast, neither red cell B2 nor B6 concentrations fell during the study period.

Conclusions: In this study red blood cell B2 and B6 remained stable over the period of study. In contrast, plasma concentrations of B2 and B6 fell and were outwith the normal range, the trough coinciding with the peak of C-reactive protein before returning to baseline values. These results are consistent with the concept that plasma concentrations of vitamins are unlikely to be a reliable measure of status in patients with evidence of a systemic inflammatory response. Red cell B1, B2 and B6 concentrations more accurately reflect status in patients with evidence of a systemic inflammatory response.

Study Purpose To assess clinical cognitive function and measure cerebral embolic load following primary cemented hip arthroplasty.

Methods 34 primary cemented hip arthroplasty patients (mean age 69.9 (SD 11.0)0 and no history of cerebrovascular disease, underwent cognitive assessment before and after (day 4) surgery. Testing included: Verbal fluency and speed (Control Oral Word Association Test); Working memory to assess immediate and delayed recall (Weschler Memory Scale III); Attention and mental processing speeds (Colour Trails 1& 2). A one sample Wilcoxon signed rank test compared median differences before and after surgery. A sub-group of 20 patients had intra-operative transcranial Doppler ultrasound monitoring of the middle cerebral artery for embolic signals. A marker of neuronal injury (S-100B protein) was measured pre-operatively and at 0, 24 and 48 hours following surgery.

Results A significant difference was noted in Colour Trails tests 1& 2 following hip arthroplasty with P values (C.I.) of 0.002 (−21, −4) and 0.023 (−15.5, −1.0) respectively.

Using established emboli criteria 10 (50%) patients had true cerebral emboli with a range from 1 to 550 signals (median 2.5 interquartile range (IQ) 2 to 12.5). S-100B levels increased from a pre-operative median (IQ) of 0.15 microg/L (0.12 to 0.20) to a peak immediately following surgery of 1.88(1.36 to 4.24) returning to 0.26(0.18 to 0.37) by 48 hours (normal range: 0.03–0.15). Plotted scatter charts indicated no correlation between embolic load and cognitive dysfunction or with S-100B levels following surgery.

Conclusion Cognitive testing indicates deterioration in early measured attention, visual searching and mental processing speed shortly following hip arthroplasty. No direct correlation was found between cognitive dysfunction and cerebral embolic load.

Femoral revision total hip arthroplasty is a technically demanding procedure, especially when there is extensive proximal femoral bone loss. Secure fixation maynot be possible to achieve if the implant relies solely on proximal metaphyseal fit. The use of a long tapered cementless stem having a microporous surface offers a strong anchorage distal to the damaged bony segment. By bypassing the compramised proximal femur, initial implant stability is achieved and a high rate of osseointegration can be expected.

We present our experience with Link MP reconstruction stem which utilises distal fixation and has a modular proximal end.. The prosthesis is made of Tilastan( Ti6AI4V Eli Titanium Alloy) with microporous texture of about 70 microns pore diameter. The distally tapered stem is angled about 3 degrees proximally to enable easy insertion of the stem. In our series there were 53 stem revisions done in 51 patients. Twenty three were males and 28 were female patients. The average age of the male patient was 66 years and that of the female was 74 years. The mean followup was 37 months( range 12–76 months.) Indications for revision were aseptic loosening in 35 cases, infected hip replacements in 8 patients and periprosthetic fracture in ten cases. Revision for infected primary arthroplasty was done in two stages with the Link MP stem inserted at the second stage.

All the proximal femoral defects were classified radiographically as described by Gustillo and Pasternak. There were 29 type 2 defects and 14 type 3 defects. The periprosthetic fractures were classified as per the Vancouver system and all the cases were type b fractures. Clinical scoring as described by d’Aubigne and Postel was used . The mean preoperative score was 3.5 while average score at the time of follow-up was 9.8. The subsidence ranged from none to 6mm. Good radiological evidence of proximal femoral restoration was seen in 44% of the cases in our series. Complications included greater trochanter fracture in 4 cases, perforation of the anterior cortex during reaming using the rasp in 2 cases and dislocation in one patient. In one case there was unacceptable penetration of the implant medially and this was subsequently treated by re-revision with a Huckstep stem. There were two intraoperative fractures which were treated with circlage wire fixation and they went on to union. None of the patients required a re-revision till date.

In conclusion , our experience with Link MP reconstruction stem has been encouraging as shown by the improved d’Aubigne & Postel scores and low rate of complications. We also observed proximal femoral restoration and high implant survivorship in our series.

Background: Long bone fractures and intramedullary stabilisation can result in the extravasation of fat and marrow emboli into the venous circulation. The effects of these emboli can become systemic causing neurological features.

Aim: To establish the cerebral microembolic load following femoral and tibial diaphyseal fractures treated by intramedullary fixation and to specify any neurological impairment with the application of a series of cognitive tests and a serum marker of neuronal injury.

Methods: 20 femoral and tibial fractures treated with intramedullary fixation had intra-operative transcranial doppler ultrasound monitoring of the middle cerebral artery with emboli detection software set to established guidelines. Cognitive testing (day 3), following surgery with an I.Q. assessment (PFSIQ) allowing comparison with age specific normative data. This included: verbal fluency and speed (COWAT – Control Oral Word Association Test); working memory with assessment of immediate and delayed recall; mini-mental state examination; executive function, attention and mental processing speeds (Colour Trails 1& 2). Beta S-100 levels measured pre-operatively, 0, 24 and 48 hours following surgery as a marker of neuronal injury.

Statistical Analysis: One sample Wilcoxon signed rank test to compare median of the cognitive scores with age matched normative data. Multiple regression analysis used to correlate embolic load with cognitive function.

Results: Mean age (SD) for the group is 32 (5.8). Mean PFSIQ of 52.8%, SD 21.4 [median 59.5, IQ range 28.3, 71.3]. No significant difference detected in cognitive testing compared with normative data. Cerebral microemboli detected in 17 of 20 patients with a count median (range) of 6 (0, 29). The mean pre-operative beta S-100 level was 0.36 micro g/l (normal range 0–0.15). This increased to a peak mean of 0.88 micro g/l immediately following surgery with a poor correlation to cerebral embolic load.

Discussion: Detailed clinical testing indicates no significant deterioration in cognitive function following intramedullary stabilisation of these fractures. A variable cerebral micro-embolic load was seen but with no detectable clinical effect. No direct correlation was found between the elevated levels of Beta S-100 seen following surgery and cerebral embolic load. This appears to correlate with previous concerns in the literature regarding the specificity and sensitivity of this established marker of neuronal injury.

Introduction Damage Control orthopaedic techniques have been proposed in the seriously injured with primary external fixation of long bone fractures, reducing the ‘second hit’ of surgery. We have developed a large animal (ovine) model for the study of major trauma.

Aim To clarify the sequence of pulmonary and systemic physiological responses over a 24-hour period following injury, comparing the effects of primary external femoral fixation to intramedullary stabilisation to better quantify the ‘second hit’ of these surgical techniques.

Methods Under terminal anaesthesia bilateral femoral diaphyseal fractures were produced using a mechanical pneumatic actuator (ram). Hypovolaemic shock was maintained for 4 hours before fluid resuscitation and surgical stabilisation.

24 sheep were randomised into 4 groups and monitored for 24 hours following injury:

Group 1 – Control Group (effects of general anaesthesia only)

Group 2 – Control Group for Trauma (injury but no long bone stabilisation)

Group 3 – Damage control group (Injury and external fixation)

Group 4 – Early total care (Injury and reamed intra-medullary stabilisation)

Outcome measures: Embolic load (Mayo score) using transoesophageal echocardiography; serum markers of coagulation (prothrombin time, activated partial thromboplastin time and fibrinogen levels) and inflammation (interleukin 6). Bronchoalveolar lavage to assess total cell count and cell differential to quantify the proportion of neutrophils present.

Results A sustained embolic shower was detected with each femoral fracture (mean Mayo score of 5 and 5.5 respectively). Intramedullary reaming and nailing produced further embolic events with a mean score of 2.5 and 1.5 respectively. Mean prothrombin time increased from a pre-fracture mean of 12 in each group to 18.8 (group 1) 20.7 (group 2); 24.8 (group 3); 31.1 (group 4). Alveolar lavage samples taken at 0, 4 and 24 hours following injury indicated a progressive neutrophilia developing in each group with a count pre-fracture of 4.3 increasing to 55.75 (group 1); 40 (group2); 49 (group3) and 31.7 (group 4) by 24 hours following injury.

Discussion The effects of damage control techniques in this model appear to be a reduced stimulation of the extrinsic coagulation system. An additional embolic hit was detected secondary to intramedullary reaming and nail insertion. Localised lung inflammation seems to develop in all groups with no significant differences seen due to treatment.

This prospective study aimed to establish if octogenarians undergoing primary hip arthroplasty experienced a similar clinical outcome and complication rate as younger patients.

A total of 585 patients were recruited over a 4-year period. Patients aged 70–79 years and 80–89 years (octogenarians) were placed into separate groups.

Harris hip and SF-36 scores were obtained before and at 6 and 18 months following surgery. Other measurements included: blood loss; blood transfusion rate; wound infection; thromboembolism; dislocation and 90-day mortality.

Statistical analysis included a two-sample t-test and chi-squared analysis with Yates correction to compare results in each group. Analysis of covariance was used to calculate confidence limits for the effect of age group on Harris hip and SF-36 scores at 6 and 18 months after adjusting for levels recorded prior to surgery. Multiple logistic regression analysis was performed to determine any predictive factors for a noted difference in blood transfusion rates between patient cohorts.

A significantly better (P=0.019) improvement in mean Harris Hip score (SD) was seen 18-months after surgery in the younger cohort (43.4 (13.8) compared to 39.8 (10.6)). Length of hospital stay was longer (P< 0.001) in the octogenarians (12.9 (SD 7.0) days versus 10.1 (SD 4.7)) with a higher blood transfusion rate of 40% compared to 28% (P = 0.009). Lower pre-operative haemoglobin levels strongly correlated with the need for blood transfusion. No significant differences in infection, dislocation, thromboembolism or 90-day mortality rates were found.

Conclusions: Octogenarians are more likely to require blood transfusion and a longer hospital stay, with less improvement in clinical outcome at 18 months after primary hip arthroplasty.

Study Design: Prospective randomized study.

Objectives: To compare the strategy of spinal fusion with that of rehabilitation for patients with chronic low back pain.

Methods: A multicentre trial of 349 candidates for spinal fusion (where both patient and surgeon were uncertain of the outcome) were randomised to either an operation that the surgeon considered was most appropriate for that patient or to an intensive rehabilitation programme. Rehabilitation was based on a 3 week (15 day) model of exercise therapy, spine stabilisation techniques and education using cognitive behavioural principles. Follow-up was at least 2 years from randomisation. The trial was 90% powered to show a 4 point difference between groups at α= 0.05. A full economic analysis is available.

Outcomes Measures: Oswestry Disability Index (ODI); the Shuttle Walking Test (SWT); SF-36 and EuroQol EQ-5D.

Results: 176 patients were randomized to surgery and 173 to rehabilitation. Demographic features including sex, age, diagnosis (spondylolisthesis, post-laminectomy syndrome, others) duration of back pain, smoking history, litigation, employment status, planned numbers of fused levels and baseline ODI were similar for both groups.

Results: For the surgery group the mean ODI improved from 46.6 (SD 14.5) to 34.9 (SD 21) at two years. For the rehabilitation group mean ODI improved from 44.8 (SD 14.8) to 36.2 (SD 20.6) at two years. For the surgery group the mean SWT improved from 254 (SD 209) to 350 (SD 244.8) at two years. For the rehabilitation group mean SWT improved from 247 (SD 185) to 310 (SD 203) at two years. For the surgery group the mean SF-36 Physical component score improved from 22.2 (SD 18) to 43.6 (SD 32.1) at two years. For the rehabilitation group the mean SF-36 Physical component score improved from 24.0 (SD 20.6) to 40.5 (SD 31.1) at two years.

Conclusions: This is a comparison of treatment strategies: There was no clinical or statistical difference in outcome between the strategy of spinal fusion and that of rehabilitation. Patients randomised to surgery (spinal stabilisation) and patients randomised to rehabilitation have indicated a treatment effect, but this may be due to natural history. The surgery results parallel those reported in other trials. At two years the treatment costs of the surgery arm were approximately twice those of the rehabilitation arm. The costs of rehabilitation depend on how many patients opt for surgery (22% in this trial). “Failed” non-operative treatment is commonly listed as an indication for surgery. “Failed” non-operative treatment should include intensive rehabilitation appropriately supported by the treating surgeon.

Aim: To assess the results of total knee arthroplasty in a cohort of patients aged 80–89 years and compare them to a similar group of patients aged 70–79

Introduction: With the average age of the population steadily rising, more patients are likely to present with arthritis over 80 years of age. The benefits of Total Knee Arthroplasty (TKA) in the treatment of osteoarthritis are widely known, but there are few studies which examine the results of TKA in octogenarians.

Methods: Data was collected prospectively from 1995–2002 on 115 patients undergoing TKA aged 80–89 years and compared to 411 patients who were aged 70–79 undergoing TKA during the same period. Patients undergoing unicompartmental, revision or bilateral TKA were excluded. Patients were seen pre-operatively and scores for SF-36, American Knee Society (AKS) score and haemoglobin were taken along with demographic data. The outcome measurements used were SF-36 score, AKS score, blood loss, length of stay, mortality and post-operative complications. These were collected during the first week post-surgery and at 6 and 18 months post-surgery.

Results: Both groups showed significant increases in AKS score at 6 months, (54.17 and 54.45, both p=0.0001). We continued to see improvement of the AKS score up to 18 months (mean 85.38 and 85.12, p= 0.55) with no significant difference between the two groups. Patients over 80 had lower pre-op Haemoglobin (Hb) (mean 13.56 and 12.23, p=0.0001) but experienced the same Hb drop post-procedure. There was no difference in postoperative complications, but the length of stay (8.3 days and 13.9 days, p=0.0001) and mortality rate (0.7% and 5%, p=0.0001) were higher.

Conclusions: Our early results show that TKA can be beneficial to patients over 80 years in terms of mobility and independence, but they have a longer in-patient hospital stay and attract a slightly higher mortality risk at 90 days.

Background: Previous studies have reported mixed findings with regards to post operative complication rates and overall outcome in elderly patients undergoing total hip arthroplasty. The aim of this study was a prospective comparison of physical and functional outcome measurements following primary hip arthroplasty in patients aged 80–90 years to those aged 70–79.

Methods: Data was prospectively recorded from 1998–2002. 144 patients aged 80–90 years underwent primary hip arthroplasty compared to 441 aged 70–79. A pre-operative Harris Hip Score was obtained on all patients and a standardized follow up regimen was used for assessment at 6, 18 and 36 months post surgery. Data collection included: intraoperative blood loss; post operative transfusion rate; incidence of wound infection, DVT and pulmonary embolus; dislocation and mortality rates. Statistical analysis involved two-sample t-test and chi-squared with Yates correction.

Results: Pre-operative Harris Hip Scores were 41.6 (SD 11.2) in the younger cohort and 39.3 (SD 12.4) in the octogenarian (P = 0.04). This score had improved by 39.3 and 38.1 points respectively (P = 0.5) at 6 months; 42.3 and 37.7 at 18 months (P = 0.02); 43.4 and 39.8 at 36 months (P = 0.24).

The mortality rate at 3 months following surgery was 4% in our octogenarian group compared to 1% (P=0.02). Mean length of hospital stay was significantly (P< 0.001) longer at 12.9 (SD 7.0) days compared to 10.1 (SD 4.7). The transfusion rate in our octogenarian group was 40% compared to 28% (P = 0.009). The incidence of deep infection was 1.4% in the older group compared to 0.5% (NS). Each group had a dislocation rate of 1%. and an incidence of DVT and pulmonary embolus that was comparable.

Discussion: Total hip arthroplasty can be performed safely in octogenarians with excellent relief of pain and improved function.

Tuberosity ‘avulsion’ fractures to the base of the fifth metatarsal respond well to symptomatic treatment. The purpose of this study was a prospective comparison of clinical and radiological outcome with treatment in a plaster slipper, compared to a tubigrip support.

Ethical approval was obtained and written consent with an information sheet issued at the first fracture clinic appointment. Forty three patients with this fracture were allocated to one of our two treatment groups and followed up at regular intervals over a 12 week period or until they were suitable for discharge. A combined foot score (maximum 100 points) was used at each follow up appointment to measure levels of pain (40 points) and function (60 points). A check radiograph was taken prior to discharge to assess union. A repeated measures analysis was used to assess any difference between the two treatment groups and whether this changed with time.

Results indicated no overall significant difference between the two treatment groups with a mean foot score of 73.5 for the tubigrip group and 80.3 for the plaster slipper group over the entire treatment period. At 2 weeks post injury the plaster group (70.9) had a significantly (p< 0.01) better combined foot score at assessment in comparison to the tubigrip group (54.1).By the 5–8 week stage, the mean combined foot scores had improved and were comparable at 89.5 (tubigrip) and 90 (plaster slipper). Radiographs taken prior to discharge indicated two patients in each treatment group with significant fracture site displacement. One patient remained clinically symptomatic and underwent surgical fixation.

In this small cohort of patients the eventual clinical and radiological outcomes were comparable. During the initial 2 week treatment phase the plaster slipper group recorded a significantly better mean foot score.

It is becoming widely accepted that research which considers only the outcome and not the costs associated with new technologies in health care, is of limited value in making decisions about the use of scarce resources. Economic evaluation is becoming a standard feature of clinical research but many published economic evaluations fall short of best practice in their methodology. We have described the essential features of economic evaluation, using published studies in orthopaedics, in order to try to improve the ability of orthopaedic surgeons to read, understand and appraise such studies critically, and to encourage them to consider including economic evaluation in future investigations.

We describe 129 patients with disabling instability of the knee due to deficiency of the anterior cruciate ligament. They were treated by replacement of the ligament with a Leeds-Keio prosthesis supplemented by an extra-articular MacIntosh lateral substitution reconstruction. After an average period of 71 months a satisfactory outcome was found in only 60% of knees. Nine had required revision because of recurrent instability and the pivot-shift sign had become positive in 40% of patients. In our opinion the long-term results are unsatisfactory when compared with those obtained using a graft from the medial third of the patellar tendon supplemented with a MacIntosh extra-articular tenodesis.

Tissues from five patients who underwent revision operations for failed total hip replacements were found to contain large quantities of particulate titanium. In four cases this metal must have come from titanium alloy screws used to fix the acetabular component; in the fifth case it may also have originated from a titanium alloy femoral head. Monoclonal antibody labelling showed abundant macrophages and T-lymphocytes, in the absence of B-lymphocytes, suggesting sensitisation to titanium. Skin patch testing with dilute solutions of titanium salts gave negative results in all five patients. However, two of them had a positive skin test to a titanium-containing ointment.