Approximately one-fifth of patients are not satisfied with total knee arthroplasty (TKA). Preoperative variables associated with poorer outcomes are severity and chronicity of pain and psychological disease, which may present as anxiety and depression. It is unclear whether this is constitutional or the result of knee pain. To address this, we explored the association of anxiety and depression with knee disability before and after TKA.

Forty patients undergoing TKA completed Hospital Anxiety and Depression Scale (HADS) and Oxford Knee Scores (OKS) preoperatively and at three and six months postoperatively. Both were elevated preoperatively and improved significantly post-operatively (P<0.001). The severity of preoperative anxiety and depression was associated with worse knee disability (coefficient −0.409, p=0.009). Postoperatively reduction in anxiety and depression was associated with improvement in knee disability after three (coefficient −0.459, p=0.003) and six months (coefficient −0.428, p=0.006).

The difficulty in interpreting preoperative anxiety and depression and the outcome of TKA is establishing whether they are the cause or effect of pain in the knee. As anxiety and depression improves with knee pain and function, this study suggests that knee pain contributes to the psychological symptoms and that a successful TKA offers an excellent chance of improving both.

We prospectively followed 191 consecutive collarless polished tapered (CPT) femoral stems, implanted in 175 patients who had a mean age at operation of 64.5 years (21 to 85). At a mean follow-up of 15.9 years (14 to 17.5), 86 patients (95 hips) were still alive. The fate of all original stems is known. The 16-year survivorship with re-operation for any reason was 80.7% (95% confidence interval 72 to 89.4). There was no loss to follow-up, with clinical data available on all 95 hips and radiological assessment performed on 90 hips (95%). At latest follow-up, the mean Harris hip score was 78 (28 to 100) and the mean Oxford hip score was 36 (15 to 48). Stems subsided within the cement mantle, with a mean subsidence of 2.1 mm (0.4 to 19.2). Among the original cohort, only one stem (0.5%) has been revised due to aseptic loosening. In total seven stems were revised for any cause, of which four revisions were required for infection following revision of the acetabular component. A total of 21 patients (11%) required some sort of revision procedure; all except three of these resulted from failure of the acetabular component. Cemented acetabular components had a significantly lower revision burden (three hips, 2.7%) than Harris Galante uncemented components (17 hips, 21.8%) (p < 0.001).

The CPT stem continues to provide excellent radiological and clinical outcomes at 15 years following implantation. Its results are consistent with other polished tapered stem designs.

Background

Venous thromboembolism deterrent (TED) stockings are recommended for all orthopaedic patients. Clinical evidence supporting their use is limited and the risk of DVT increases four-fold if pressure gradients are reversed. This study aims to investigate the efficacy of TED stockings and their application using pressure gradients as the outcome measure.

We reviewed the seven- to ten-year results of our previously reported prospective randomised controlled trial comparing total hip replacement and hemiarthroplasty for the treatment of displaced intracapsular fracture of the femoral neck. Of our original study group of 81 patients, 47 were still alive.

After a mean follow up of nine years (7 to 10) overall mortality was 32.5% and 51.2% after total hip replacement and hemiarthroplasty, respectively (p = 0.09). At 100 months postoperatively a significantly greater proportion of hemiarthroplasty patients had died (p = 0.026). Three hips dislocated following total hip replacement and none after hemiarthroplasty. In both the total hip replacement and hemiarthroplasty groups a deterioration had occurred in walking distance (p = 0.02 and p < 0.001, respectively). One total hip replacement required revision compared with four hemiarthroplasties which were revised to total hip replacements. All surviving patients with a total hip replacement demonstrated wear of the cemented polyethylene component and all hemiarthroplasties had produced acetabular erosion.

There was lower mortality (p = 0.013) and a trend towards superior function in patients with a total hip replacement in the medium term.

We compared the medium-term clinical and radiological results of hybrid total hip replacement (THR) with metal-on-metal Birmingham hip resurfacing (BHR) in two groups of 54 young patients matched for age, gender, body mass index and pre-operative levels of activity.

The clinical outcome was assessed by the University of California, Los Angeles (UCLA) activity score, the Oxford Hip Score (OHS) and the EuroQol scores. Radiologically, all hips were assessed for migration and osteolysis, the hybrid THRs for polyethylene wear and the BHRs for a pedestal sign. The mean follow-up of the patients with a hybrid THR was ten years and for those with a BHR, nine years. Four patients with a hybrid THR and one with a BHR had died. In each group five were lost to follow-up. The revision rate of the hybrid THRs was 16.7% (9 of 54) and of the BHRs 9.3% (5 of 54) (p = 0.195). Radiographs of a further eight hybrid THRs demonstrated wear and osteolysis, and they await revision (p = 0.008). Of the unrevised BHRs 90% had radiological changes, of which approximately 50% had progressed over the previous four years. All hybrid THRs demonstrated linear polyethylene wear with a mean of 1.24 mm (0.06 to 3.03). The BHRs recorded superior OHS (p = 0.013), UCLA (p = 0.008), and EuroQol visual analogue scores (p = 0.009).

After nine years, patients with BHRs remained more active and had a lower rate of revision than those with hybrid THRs. Both groups demonstrated progressive radiological changes at medium-term follow-up.

Resurfacing hip arthroplasty is a successful option for the treatment of the young and active patient with hip arthritis. However, it is complicated by femoral neck fracture and avascular necrosis, which result from devascularisation during surgery. Devascularisation maybe caused by thermal necrosis. Thermal necrosis of bone has been shown to occur in temperatures of 47°C and above. We investigated the temperatures generated during femoral head preparation to see if the temperatures reached were great enough to induce osteonecrosis.

Method: Eight patients with osteoarthritis underwent standard resurfacing hip arthroplasty through the posterior approach. From the first over-drilling of the femoral heads until the prosthesis was cemented in place the temperatures generated at the bone surface were recorded using an infra-red thermal imaging camera. Images were captured every 4 seconds as the operation was performed with no interference to the surgeon

Results: The maximum temperatures generated occurred during sleeve reaming at 88.4°C. Seven patients had a temperature recorded greater than 47°C. Removing the femoral caput with an oscillating saw had the highest mean temperature 62.2°C, followed by sleeve reaming (mean 48.7°C). Female patients had the lowest temperature rises and patients receiving the larger femoral prosthesis the greatest temperatures at the bone surface.

Conclusions: Heat generated during femoral head preparation exceeded 47°C in all but one case. Osteonecrosis secondary to thermal insult is likely to occur during femoral head preparation. Strategies need to be devised to decrease the temperatures generated during femoral head preparation.

Introduction: Resurfacing hip arthroplasty is a successful option for the treatment of the young and active patient with hip arthritis. However, it is complicated by femoral neck fracture and avascular necrosis, which may result from devascularisation during surgery. Devascularisation maybe caused by thermal necrosis. Thermal necrosis of bone has been shown to occur in temperatures of 47°C and above. We investigated the temperatures generated during femoral head preparation to see if the temperatures reached were great enough to induce osteonecrosis.

Method: Eight patients with osteoarthritis underwent standard resurfacing hip arthroplasty through the posterior approach. From the first over-drilling of the femoral heads until the prosthesis was cemented in place the temperatures generated at the bone surface were recorded using an infra-red thermal imaging camera. Images were captured every 4 seconds as the operation was performed with no interference to the surgeon

Results: The maximum temperatures generated occurred during sleeve reaming at 88.4°C. Seven patients had a temperature recorded greater than 47°C. Removing the femoral caput with an oscillating saw had the highest mean temperature 62.2°C, followed by sleeve reaming (mean 48.7°C). Female patients had the lowest temperature rises and patients receiving the larger femoral prosthesis the greatest temperatures at the bone surface.

Conclusions: Heat generated during femoral head preparation exceeded 47°C in all but one case. Osteonecrosis secondary to thermal insult is likely to occur during femoral head preparation. Strategies need to be devised to decrease the temperatures generated during femoral head preparation.

We undertook a randomised controlled trial to compare the outcomes of skin adhesive and staples for skin closure in total hip replacement. The primary outcome was the cosmetic appearance of the scar at three months using a surgeon-rated visual analogue scale. In all, 90 patients were randomised to skin closure using either skin adhesive (n = 45) or staples (n = 45). Data on demographics, surgical details, infection and oozing were collected during the in-patient stay. Further data on complications, patient satisfaction and evaluation of cosmesis were collected at three-month follow-up, and a photograph of the scar was taken. An orthopaedic and a plastic surgeon independently evaluated the cosmetic appearance of the scars from the photographs. No significant difference was found between groups in the cosmetic appearance of scars at three months (p = 0.172), the occurrence of complications (p = 0.3), or patient satisfaction (p = 0.42). Staples were quicker and easier to use than skin adhesive and also less expensive. Skin adhesive and surgical staples are both effective skin closure methods in total hip replacement.

We have reviewed 70 Harris-Galante uncemented acetabular components implanted as hybrid hip replacements with cemented stems between 1991 and 1995 in 53 patients whose mean age was 40 years (19 to 49). The mean follow-up was for 13.6 years (12 to 16) with no loss to follow-up. We assessed the patients both clinically and radiologically.

The mean Oxford hip score was 20 (12 to 46) and the mean Harris hip score 81 (37 to 100) at the final review. Radiologically, 27 hips (39%) had femoral osteolysis, 13 (19%) acetabular osteolysis, and 31 (44%) radiolucent lines around the acetabular component. Kaplan-Meier survival curves were constructed for the outcomes of revision of the acetabular component, revision of the component and polyethylene liner, and impending revision for progressive osteolysis.

The cumulative survival for revision of the acetabular component was 94% (95% confidence interval 88.4 to 99.7), for the component and liner 84% (95% confidence interval 74.5 to 93.5) and for impending revision 55.3% (95% confidence interval 40.6 to 70) at 16 years.

Uncemented acetabular components with polyethylene liners undergo silent lysis and merit regular long-term radiological review.

Introduction: Inadequate cementation of the acetabular component in hip replacement surgery leads to early aseptic loosening, the most common cause of revision. The optimum method of cementation has not been fully evaluated. This study aimed to determine the effect of the acetabular component flange on mean and peak pressure during component insertion.

Method: A 53mm deepened hemisphere was machined from aluminium. Pressure transducers were positioned at the rim, at 45 degrees, and at the base. Polyethelene acetabular components of different sizes and flange designs were mounted onto a materials testing machine and inserted at a constant rate into Palacos R cement within the aluminium hemisphere. Insertion was stopped at a pre-determined point when an even cement mantle was achieved. The same components were then tested without a flange. Each test was repeated six times. Output data from the transducers was analysed.

Results: Components with a flange create a mean pressure 6–18 times higher at the rim than those without a flange. At the base pressures are 2–4 times higher. A stiffer flange generates higher peak and mean pressures than a more malleable flange. Delaying insertion by one minute does not increase the pressures achieved unless a flange is used.

Discussion: These results strongly support the use of a flange to contain cement during insertion of the acetabular component. Unflanged components fail to achieve satisfactory mean or peak pressures, even if insertion is delayed. This is likely to result in poor cement penetration into bone and reduced longevity of interface fixation.

We have determined the 10 year life expectancy of 5,831 patients who had undergone 6,653 elective primary total hip replacements (THR) at a regional orthopaedic centre between April 1993 and October 2004.

Methods: We ascertained dates of deaths for all those who had undergone surgery during this period and constructed Kaplan Meier survivorship curves for these patients. Standardized mortality ratios were calculated by comparing this data with available UK mortality rates for the same age groups over the same time period.

Results: The mean age at operation was 73 with a male to female ratio of 2:3. Of those with 10 year follow up 29.5% had died a mean of 5.6 years after surgery. 10-year survivorship was 89% in patients under 65 years at surgery, 75% in patients aged between 65 – 74 years and 51% in patients over 75.

The standard mortality rates were significantly higher than expected for patients under 45 years, 20% higher for those between 45 and 64 years and progressively less than expected for patients aged 65 and over.

Discussion: By comparing our mortality curves with prosthesis survivorship curves from the most recent Swedish Arthroplasty Register results we were able to demonstrate that the survivorship of cemented hip arthroplasties exceeds that of the patients over the age of 60 in our area. As these prostheses are less expensive than their uncemented equivalents this suggests these are the prosthesis of choice in this age group.

We determined the 10 year life expectancy of 5,831 patients who had undergone 6,653 elective primary total hip replacements (THR) at a regional orthopaedic centre between April 1993 and October 2004. Using Hospital, General Practitioner (GP) and the local health authority’s records, we determined dates of deaths for all those who had undergone surgery during this period.

The mean age at operation was 73 (13–96) with a male to female ratio of 2:3. Of those with 10 year follow up 29.5% had died a mean of 5.6 (0–11.1) years after surgery. Using Kaplan Meier curves, 10-year survivorship was 89% in patients under 65 years at surgery, 75% in patients aged between 65 – 74 years and 51% in patients over 75.

The standardised mortality rates (SMR) were significantly higher than expected for patients under 45 years, 20% higher for those between 45 and 64 years and progressively less than expected for patients aged 65 and over.

The survivorship of cemented hip arthroplasties (derived from the Swedish Arthroplasty Register 2004) exceeds patients’ life expectancy in those over the age of 60 in our area suggesting that this is the procedure of choice in this population.

Introduction: Arthroplasty is the most effective management of displaced intracapsular femoral neck fracture. Hemiarthroplasty (HEMI) is associated with acetabular erosion and loosening in mobile active patients and total hip arthroplasty (THA) with instability.

We sought to establish whether HEMI or THA gave better results in independent mobile patients with displaced femoral neck fracture.

Method: Eighty-one patients were randomised into two groups. One arm received a modular HEMI, the second a THA using the same femoral stem. Patients were followed for a mean of three years after surgery.

Results: After HEMI, eight patients died, two were revised to THA and there is intention to revise three. One patient had a Peri-prosthetic fracture. Mean walking distance was 1.08 miles and Oxford Hip Score (OHS) 22.5. Twenty patients (64.5% of survivors) had radiological evidence of acetabular erosion.

After THA, three patients died, three dislocated, one required revision. Mean walking distance was 2.23 miles and OHS was 18.8. There was no radiological evidence of polyethylene wear

Patients with THAs after three years walked further (p=0.039) and had a lower OHS (p=0.033).

Discussion: HEMI is associated with a higher actual and potential revision rate than THA because of acetabular erosion, higher OHS after three years and shorter walking distances.

THA is a preferable option to HEMI in independent mobile elderly patients with displaced intracapsular femoral neck fracture.

We retrospectively reviewed 175 patients (191 hips) who had undergone primary cemented total hip replacement between November 1992 and November 1995 using a collarless polished double-tapered femoral component after a minimum of ten years (mean 11.08; 10 to 12.8). All stems were implanted using contemporary cementing techniques with a distal cement restrictor, pressurised lavage, retrograde cementing with a gun and proximal pressurisation. Clinical outcome was assessed using the Harris Hip score. Radiological analysis was performed on calibrated plain radiographs taken in two planes. Complete radiological data on 110 patients (120 hips) and clinical follow-up on all the surviving 111 patients (122 hips) was available. The fate of all the hips was known.

At final follow-up, the mean Harris Hip score was 86 (47 to 100), and 87 of 116 patients (75%) had good or excellent scores. Survival with revision of the stem for aseptic loosening as the endpoint was 100%; and survival with revision of the stem for any reason was 95.9% (95% confidence interval 87.8 to 96.8) at ten years. All the stems subsided vertically at the stem-cement interface in a predictable pattern, at an overall mean rate of 0.18 mm per year (0.02 to 2.16), but with a mean rate of 0.80 mm (0.02 to 2.5) during the first year. The mean total subsidence was 1.95 mm (0.21 to 24). Only three stems loosened at the cement-bone interface. There was excellent preservation of proximal femoral bone stock. There was a high incidence of Brooker III and IV heterotopic ossification affecting 25 patients (22%).

The collarless polished tapered stem has an excellent clinical and radiological outcome at a minimum of ten years’ follow-up. The pattern and magnitude of subsidence of the stem within the cement mantle occurred in a predictable pattern, consistent with the design philosophy.

We determined the ten-year life expectancy of 5831 patients who had undergone 6653 elective primary total hip replacements at a regional orthopaedic centre between April 1993 and October 2004. Using hospital, general practitioner and the local health authority records, we recorded the dates of death for those who died following surgery.

The mean age at operation was 67 years (13 to 96) with a male:female ratio of 2:3. Of 1154 patients with a ten-year follow-up 340 (29.5%) had died a mean of 5.6 years (0 to 10) after surgery. Using Kaplan-Meier curves, the ten-year survival was 89% in patients under 65 years at surgery, 75% in patients aged between 65 and 74 years, and 51% in patients over 75.

The standardised mortality rates were considerably higher for patients under 45 years, 20% higher for those between 45 and 64 years, and steadily reduced in patients aged 65 and over.

The survival of cemented hip replacement derived from the Swedish Hip Arthroplasty Register Annual Report 2004 exceeds the life expectancy of patients over the age of 60 in our area, suggesting that cemented hip replacement is the procedure of choice in this population.

We determined the effect of the surgical approach on perfusion of the femoral head during hip resurfacing arthroplasty by measuring the concentration of cefuroxime in bone samples from the femoral head. A total of 20 operations were performed through either a transgluteal or an extended posterolateral approach.

The concentration of cefuroxime in bone was significantly greater when using the transgluteal approach (mean 15.7 mg/kg; 95% confidence interval 12.3 to 19.1) compared with that using the posterolateral approach (mean 5.6 mg/kg; 95% confidence interval 3.5 to 7.8; p < 0.001). In one patient, who had the operation through a posterolateral approach, cefuroxime was undetectable.

Using cefuroxime as an indirect measure of blood flow, the posterolateral approach was found to be associated with a significant reduction in the blood supply to the femoral head during resurfacing arthroplasty compared with the transgluteal approach.

We reviewed 142 consecutive primary total hip replacements implanted into 123 patients between 1988 and 1993 using the Exeter Universal femoral stem. A total of 74 patients (88 hips) had survived for ten years or more and were reviewed at a mean of 12.7 years (10 to 17). There was no loss to follow-up.

The rate of revision of the femoral component for aseptic loosening and osteolysis was 1.1% (1 stem), that for revision for any cause was 2.2% (2 stems), and for re-operation for any cause was 21.6% (19 hips). Re-operation was because of failure of the acetabular component in all but two hips.

All but one femoral component subsided within the cement mantle to a mean of 1.52 mm (0 to 8.3) at the final follow-up. One further stem had subsided excessively (8 mm) and had lucent lines at the cement-stem and cement-bone interfaces. This was classified as a radiological failure and is awaiting revision. One stem was revised for deep infection and one for excessive peri-articular osteolysis. Defects of the cement mantle (Barrack grade C and D) were found in 28% of stems (25 hips), associated with increased subsidence (p = 0.01), but were not associated with endosteal lysis or failure.

Peri-articular osteolysis was significantly related to the degree of polyethylene wear (p < 0.001), which was in turn associated with a younger age (p = 0.01) and male gender (p < 0.001).

The use of the Exeter metal-backed acetabular component was a notable failure with 12 of 32 hips (37.5%) revised for loosening. The Harris-Galante components failed with excessive wear, osteolysis and dislocation with 15% revised (5 of 33 hips). Only one of 23 hips with a cemented Elite component (4%) was revised for loosening and osteolysis.

Our findings show that the Exeter Universal stem implanted outside the originating centre has excellent medium-term results.

We compared the five- to seven-year clinical and radiological results of the metal-on-metal Birmingham hip resurfacing with a hybrid total hip arthroplasty in two groups of 54 hips, matched for gender, age, body mass index and activity level.

Function was excellent in both groups, as measured by the Oxford hip score, but the Birmingham hip resurfacings had higher University of California at Los Angeles activity scores and better EuroQol quality of life scores. The total hip arthroplasties had a revision or intention-to-revise rate of 8%, and the Birmingham hip resurfacings of 6%. Both groups demonstrated impending failure on surrogate end-points. Of the total hip arthroplasties, 12% had polyethylene wear and osteolysis under observation, and 8% of Birmingham hip resurfacings showed migration of the femoral component. Polyethylene wear was present in 48% of the hybrid hips without osteolysis. Of the femoral components in the Birmingham hip resurfacing group which had not migrated, 66% had radiological changes of unknown significance.

The aim of this study was to determine the outcome of total hip arthroplasty, with regard to dislocation, at our unit.

1727 primary total joint arthroplasties and 305 revision total hip arthroplasties were performed between 1993 and 1996 at our unit. We followed up 1567 of the primary hip arthroplasties and 284 of the revision hip arthroplasties at 8 to 11 years post surgery. Patients were traced by postal questionnaire, telephone interview or examination of case notes of the deceased.

The dislocation rates by approach were: 23 out of 555 (4.1%) for the posterior approach, 0 out of 120 (0%) for the Omega approach and 30 out of 892 (3.4%) for the modified Hardinge approach.

58.5% of dislocations after primary total hip arthroplasty were recurrent. The mean number of dislocations per patient was 2.81.

8.1% of revision total hip arthroplasties suffered dislocation. 70% of these became recurrent. The mean number of dislocations per patient was 2.87. The vast majority of dislocations occur within 3 months of surgery.

To our knowledge this is the largest multisurgeon audit of dislocation after total hip arthroplasty published in the United Kingdom. The follow-up of 8 to 11 years is longer than most comparable studies.

Introduction and aims: Leg length discrepancy (LLD) after total hip arthroplasty (THA) has been associated with a number of complications. The aim of this study was to assess the influence of LLD on the outcome of THA by comparing patients’ perception and their Oxford Hip Score with their anatomical leg length. A secondary aim was to identify the site at which LLD was created intraoperatively.

Methods: LLD and hip function were assessed in 90 patients undergoing primary total hip arthroplasty before and 3 months after surgery. Hip function was measured by the Oxford Hip Score (OHS). We measured leg length on pre- and postoperative radiographs and the position of the centre of rotation and the stem length on the postoperative radiographs.

Results: Post operatively 62% of patients’ limbs were lengthened by a mean of 9 mm. This was perceived by 43% of the lengthened patients. The OHS in patients who perceived true lengthening was 27% worse than the rest of the population. In 98%, lengthening occurred in the femoral component. 20% perceived true shortening and their OHS was not affected.

Conclusion: The problem of LLD after THA is lengthening. Accurate placement of the femoral component and especially avoiding overlengthening could significantly reduce patients’ perception of this.

We assessed leg length discrepancy and hip function in 90 patients undergoing primary total hip arthroplasty before surgery and at three and 12 months after. Function was measured using the Oxford hip score (OHS). After surgery the mean OHS improved by 26 points after three months and by 30 points after 12.

After operation 56 (62%) limbs were long by a mean of 9 mm and this was perceived by 24 (43%) patients after three months and by 18 (33%) after 12. The mean OHS in patients who perceived true lengthening was 27% worse than the rest of the population after three months and 18% worse after 12. In 55 (98%) patients, lengthening occurred in the femoral component. Appropriate placement of the femoral component could significantly reduce a patient’s perception of discrepancy of length.

Claims for personal injury after whiplash injury cost the economy of the United Kingdom more than £3 billion per year, yet only very few patients have radiologically demonstrable pathology. Those sustaining fractures of the cervical spine have been subjected to greater force and may reasonably be expected to have worse symptoms than those with whiplash injuries.

Using the neck disability index as the outcome measure, we compared pain and functional disability in four groups of patients who had suffered injury to the cervical spine. After a mean follow-up of 3.5 years, patients who had sustained fractures of the cervical spine had significantly lower levels of pain and disability than those who had received whiplash injuries and were pursuing compensation (p < 0.01), but had similar levels to those whiplash sufferers who had settled litigation or had never sought compensation.

Functional recovery after neck injury was unrelated to the physical insult. The increased morbidity in whiplash patients is likely to be psychological and is associated with litigation.

The aim of our study was to determine the current incidence and outcome of infected total knee arthroplasty (TKA) in our unit comparing them with our earlier audit in 1986, which had revealed infection rates of 4.4% after 471 primary TKAs and 15% after 23 revision TKAs at a mean follow-up of 2.8 years. In the interim we introduced stringent antibiotic prophylaxis, and the routine use of occlusive clothing within vertical laminar flow theatres and 0.05% chlorhexidine lavage during arthroplasty surgery.

We followed up 931 primary TKAs and 69 revision TKAs for a mean of 6.5 years (5 to 8). Patients were traced by postal questionnaire, telephone interview or examination of case notes of the deceased.

Nine (1%) of the patients who underwent primary TKA, and four (5.8%) of those who underwent revision TKA developed deep infection. Two of nine patients (22.2%) who developed infection after primary TKA were successfully treated without further surgery. All four of the patients who had infection after revision TKA had a poor outcome with one amputation, one chronic discharging sinus and two arthrodeses.

Patients who underwent an arthrodesis had comparable Oxford knee scores to those who underwent a two-stage revision. Although infection rates have declined with the introduction of prophylactic measures, and more patients are undergoing TKA, the outcome of infected TKA has improved very little.

Introduction: Aseptic loosening is the main cause of revision in hip replacement surgery. Improved cementation techniques have reduced the rate of loosening of the femoral component, leaving the cemented acetabular cup as the major problem, with reported loosening rates as high as 25% at 12 – 15 years. The ideal method of acetabular cementation has not been fully evaluated.

Aim: To determine the ideal thickness of cement mantle to resist torsional forces.

Method: Mahogany blocks with a 54mm hemispherical hole were used to simulate an acetabular socket. Machined aluminium cups were created in 5 sizes (52mm to 44mm) to give a cement mantle that varied in size from 1mm to 5mm. Three 10mm keyholes were drilled in the blocks and appropriate-sized spacers were inserted to ensure the mantle was accurate and even. Silicone grease was used to prevent any micro-interlock between cement and wood. The cups were then cemented into the wooden blocks using vacuum-mixed Palacos R cement and left to cure in air for 7 days at 37 °C. The constructs were tested to failure using a servo-hydraulic testing machine. Each experiment was repeated six times.

Results: The stiffness of the cement mantle varied according to thickness as follows:

Discussion: A stiffer cement mantle will transfer more torque to the bone-cement interface, possibly leading to earlier loosening of the prosthesis. This biomechanical analysis suggests that surgeons should aim to achieve a mantle at least 2mm thick. There appears to be little further mechanical advantage gained if the mantle is increased in thickness beyond 4mm.

Our aim in this study was to determine the outcome of hip arthroplasty with regard to infection at our unit. Infection after total joint arthroplasty is a devastating complication. The MRC study in 1984 recommended using vertical laminar flow and prophylactic antibiotics to reduce infection rates. These measures are now routinely used. Between 1993 and 1996, 1727 primary total hip arthroplasties and 305 revision hip arthroplasties were performed and 1567 of the primary and 284 of the revision arthroplasties were reviewed between five and eight years after surgery by means of a postal questionnaire, telephone interview or examination of the medical records of those who had died.

Seventeen (1.08%) of the patients who underwent primary and six (2.1%) of those who underwent revision arthroplasty had a post-operative infection. Only 0.45% of patients who underwent primary arthroplasty required revision for infection.

To our knowledge this is the largest multi-surgeon audit of infection after total hip replacement in the UK. The follow-up of between five and eight years is longer than that of most comparable studies. Our study has shown that a large cohort of surgeons of varying seniority can achieve infection rates of 1% and revision rates for infection of less than 0.5%.

The rate of deep infection following primary joint replacement has reduced to below 1%, but the cost remains high. The surgical team is the most important source of bacteria causing infection. All surgical gowns are susceptible to penetration by these organisms, which may then spread to the wound via the surgeon’s hands or contact with wet drapes without ever being airborne.

There is insufficient clinical data on the penetration of bacteria through surgical gowns, in part due to the difficulty of in vivo measurement. A simple new method was developed, using petri dishes filled with horse blood agar that were attached to the outside of the gown material. This was used to assess bacterial penetration through disposable spun-bonded polyester gowns and re-usable woven polyester gowns during normal use.

There was a significant difference between the two gown types when tested in the axilla (p < 0. 05), the groin (p < 0. 05) and the peri-anal region (p < 0. 01), with the disposable gowns performing to a higher standard.

Re-usable gowns demonstrated significant variation in penetrability. This is most likely to be due to the number of laundering and sterilisation cycles that they had undergone. Unless the continued satisfactory performance of multiple-use gowns can be guaranteed, they may be unsuitable for use in orthopaedic implant surgery.

Aseptic loosening of the acetabular component is the main reason for revision hip arthroplasty surgery with loosening rates reported at 25% at 12–15years. The optimum method of acetabular preparation and cementation technique has not been fully evaluated. Clinical follow-up studies suggest multiple keyholes improve survival rates.

Keyholes increase penetration of cement and torsional resistance of the bone-cement interface. Some studies support the traditional three 1/2 inch keyholes other studies have shown multiple smaller holes improve stability. The optimum size and number of holes to provide the strongest fixation has yet to be determined.

Using an established 54mm diameter acetabular model, mahogany, three sizes of keyhole were tested-3x10mm holes, 12x5mm, and 48x2.5mm- the surface area of the defects created were the same in each group. The model acetabulum was filled with cement and a metal central bar inserted through which torque could be applied using an Instron machine. Six specimens from each group were tested. Three 10mm holes produced a significantly stronger resistance to torque when compared to 2.5mm (p≤0.017) and 5mm holes (p≤0.001). There was no significant difference between 2.5mm and 5mm holes (p≤0.139). Each addition of a further 10mm hole significantly increased the torque strength until the model was destroyed at six holes.

In laboratory testing larger key holes provide a stronger cement-acetabular interface.

Twelve patients undergoing total hip replacements were given 600mg linezolid as a 20min intravenous infusion along with conventional prophylaxis of 1gm cefamandole immediately before surgery. Routine total hip arthroplasty was performed and at timed intervals during surgery, samples of bone, fat, muscle and blood were collected for assay by HPLC analysis. Samples of haematoma fluid that formed around the operation site and further blood samples were also collected at timed intervals following the operation for assay. The penetration of linezolid into bone was rapid with mean levels of 9.1mg/L (95% CI: 7.7–10.6mg/L) achieved at 10min after the infusion, decreasing to 6.3mg/L (95% CI: 3.9–8.6mg/L) at 30min. Correcting for the simultaneous blood concentrations gave values for bone penetration of 51% at 10min, 60% at 20min and 47% at 30min. although the penetration of linezolid into fat was also rapid, mean levels and degree of penetration were approximately 60% of those seen in bone at 10min: 4.5mg/L (95%CI:3–6.1mg/L; penetration 27%) 20min: 5.2mg/L (95% CI:4–6.4mg/L; penetration 37%) and 30min:4.1mg/L (95% CI:3.3–4.8mg/L; penetration 31%). For muscle, the corresponding values were 10min: 10.4mg/L (95%CI:8.1–12.7mg/L; penetration 58%), 20min 13.4mg/L (95%:10.2–16.5mg/L; penetration 94%) and 30min 12mg/L (95% CI:9.2–14.8mg/L; penetration 93%). Mean concentration of linezolid in the haematoma around the operation site were 8.2mg/L at 6–8h and 5.6mg/L at 8–10h after the infusion and 7mg/L at 2–4h following a second 600mg infusion given 12h postoperatively.

We conclude that linezolid exhibits rapid penetration in bone, fat and muscle of patients undergoing hip arthroplasty to achieve levels in excess of the MIC for sensitive organisms (MIC of < _ 4mg/L); with therapeutic levels maintained in the drainage which surrounds the operation site for more than 16h. This pharmaco-kinetic profile is similar to those of agents currently used for the treatment of bone and associated soft tissue infections and suggests a role for linezolid in the management of such patients

We undertook a prospective, randomised study to compare the analgesic effect of injection of steroid and of extracorporeal shock-wave therapy (ESWT) for the treatment of tennis elbow. Group 1 received a single injection of 20 mg of triamcinolone with lignocaine while group 2 received 2000 shock waves in three sessions at weekly intervals. After six weeks there was a significant difference between the groups with the mean pain score for the injection group falling from 66 to 21 compared with a decrease from 61 to 35 in the shock-wave group (p = 0.05). After three months, 84% of patients in group 1 were considered to have had successful treatment compared with 60% in group 2.

In the medium term local injection of steroid is more successful and 100 times less expensive than ESWT in the treatment of tennis elbow.

Percutaneous repair of the ruptured tendo Achillis has a low rate of failure and negligible complications with the wound, but the sural nerve may be damaged. We describe a new technique which minimises the risk of injury to this nerve.

The repair is carried out using three midline stab incisions over the posterior aspect of the tendon. A No. 1 nylon suture on a 90 mm cutting needle approximates the tendon with two box stitches. The procedure can be carried out under local anaesthesia.

We reviewed 27 patients who had a percutaneous repair at a median interval of 35 months after the injury. They returned to work at four weeks and to sport at 16. One developed a minor wound infection and another complex regional pain syndrome type II. There were no injuries to the sural nerve or late reruptures. This technique is simple to undertake and has a low rate of complications.

Nerve injury is a rare complication of total hip replacement which may be related to the exposure used for the operation. The posterior approach is traditionally associated with injury to the sciatic nerve. We have compared the incidence of nerve injury after primary total hip replacement (THR) using either a posterior or a direct lateral approach.

We studied 42 consecutive patients undergoing primary total hip replacement. The surgeons used a posterior (22 patients) or direct lateral (20 patients) approach in accordance with their normal practice. The obturator, femoral, posterior tibial and common peroneal nerves were assessed clinically and electrophysiologically by electromyography (EMG) and measurement of the velocity of nerve conduction before operation and at four weeks after.

All patients were free from symptoms of nerve injury after operation but five lesions were identified in four patients by the electrophysiological studies; the obturator nerve was involved in two, the femoral in one, the common peroneal in one and the posterior tibial in one. All these injuries occurred using the lateral approach.

Clinical assessment alone underestimates the incidence of nerve injury complicating THR. Our study does not confirm the association of nerve injury with the posterior approach which had been described previously.

Forty patients with a whiplash injury who had been reviewed previously 2 and 10 years after injury were assessed again after a mean of 15.5 years by physical examination, pain and psychometric testing.

Twenty-eight (70%) continued to complain of symptoms referable to the original accident. Neck pain was the commonest, but low-back pain was present in half. Women and older patients had a worse outcome. Radiating pain was more common in those with severe symptoms.

Evidence of psychological disturbance was seen in 52% of patients with symptoms. Between 10 and 15 years after the accident 18% of the patients had improved whereas 28% had deteriorated.