Bone cements produced by different manufacturers vary in their mechanical properties and antibiotic elution characteristics. Small changes in the formulation of a bone cement, which may not be apparent to surgeons, can also affect these properties. The supplier of Palacos bone cement with added gentamicin changed in 2005. We carried out a study to examine the mechanical characteristics and antibiotic elution of Schering-Plough Palacos, Heraeus Palacos and Depuy CMW Smartset bone cements.

Both Heraeus Palacos and Smartset bone cements performed significantly better than Schering-Plough Palacos in terms of mechanical characteristics, with and without additional vancomycin (p < 0.001). All cements show a deterioration in flexural strength with increasing addition of vancomycin, albeit staying above ISO minimum levels. Both Heraeus Palacos and Smartset elute significantly more gentamicin cumulatively than Schering-Plough Palacos. Smartset elutes significantly more vancomycin cumulatively than Heraeus Palacos.

The improved antibiotic elution characteristics of Smartset and Heraeus Palacos are not associated with a deterioration in mechanical properties. Although marketed as the ‘original’ Palacos, Heraeus Palacos has significantly altered mechanical and antibiotic elution characteristics compared with the most commonly-used previous version.

We audited the relationship between obesity and the age at which hip and knee replacement was undertaken at our centre. The database was analysed for age, the Oxford hip or knee score and the body mass index (BMI) at the time of surgery. In total, 1369 patients were studied, 1025 treated by hip replacement and 344 by knee replacement. The patients were divided into five groups based on their BMI (normal, overweight, moderately obese, severely obese and morbidly obese).

The difference in the mean Oxford score at surgery was not statistically significant between the groups (p > 0.05). For those undergoing hip replacement, the mean age of the morbidly obese patients was ten years less than that of those with a normal BMI. For those treated by knee replacement, the difference was 13 years. The age at surgery fell significantly for those with a BMI > 35 kg/m² for both hip and knee replacement (p > 0.05). This association was stronger for patients treated by knee than by hip replacement.

Allografts of bone from the femoral head are often used in orthopaedic procedures. Although the donated heads are thoroughly tested microscopically before release by the bone bank, some surgeons take additional cultures in the operating theatre before implantation. There is no consensus about the need to take these cultures. We retrospectively assessed the clinical significance of the implantation of positive-cultured bone allografts. The contamination rate at retrieval of the allografts was 6.4% in our bone bank. Intra-operative cultures were taken from 426 femoral head allografts before implantation; 48 (11.3%) had a positive culture. The most frequently encountered micro-organism was coagulase-negative staphylococcus. Deep infection occurred in two of the 48 patients (4.2%). In only one was it likely that the same micro-organism caused the contamination and the subsequent infection.

In our study, the rate of infection in patients receiving positive-cultured allografts at implantation was not higher than the overall rate of infection in allograft surgery suggesting that the positive cultures at implantation probably represent contamination and that the taking of additional cultures is not useful.

Patients who have undergone total hip or knee replacement (THR and TKR, respectively) are at high risk of venous thromboembolism. We aimed to determine the time courses of both the incidence of venous thromboembolism and effective prophylaxis. Patients with elective primary THR and TKR were enrolled in the multi-national Global Orthopaedic Registry. Data on the incidence of venous thromboembolism and prophylaxis were collected from 6639 THR and 8326 TKR patients.

The cumulative incidence of venous thromboembolism within three months of surgery was 1.7% in the THR and 2.3% in the TKR patients. The mean times to venous thromboembolism were 21.5 days (sd 22.5) for THR, and 9.7 days (sd 14.1) for TKR. It occurred after the median time to discharge in 75% of the THR and 57% of the TKA patients who developed venous thromboembolism. Of those who received recommended forms of prophylaxis, approximately one-quarter (26% of THR and 27% of TKR patients) were not receiving it seven days after surgery, the minimum duration recommended at the time of the study.

The risk of venous thromboembolism extends beyond the usual period of hospitalisation, while the duration of prophylaxis is often shorter than this. Practices should be re-assessed to ensure that patients receive appropriate durations of prophylaxis.

This prospective study evaluates the role of new laboratory markers in the diagnosis of deep implant infection in 78 patients (41 men and 37 women) with a revision total knee or hip replacement.

The mean age at the time of operation was 64.0 years (19 to 90). Intra-operative cultures showed that 21 patients had a septic and 57 an aseptic total joint replacement. The white blood cell count, the erythrocyte sedimentation rate and levels of C-reactive protein, interleukin-6, procalcitonin and tumour necrosis factor (TNF)-α were measured in blood samples before operation. The diagnostic cut-off values were determined by Received Operating Characteristic curve analysis.

C-reactive protein (> 3.2 md/dl) and interleukin-6 (> 12 pg/ml) have the highest sensitivity (0.95). Interleukin-6 is less specific than C-reactive protein (0.87 vs 0.96). Combining C-reactive protein and interleukin-6 identifies all patients with deep infection of the implant. Procalcitonin (> 0.3 ng/ml) and TNF-α (> 40 ng/ml) are very specific (0.98 vs 0.94) but have a low sensitivity (0.33 vs 0.43).

The combination of C-reactive protein and interleukin-6 measurement provide excellent screening tests for infection of a deep implant. A highly specific marker such as procalcitonin and pre-operative aspiration of the joint might be useful in identifying patients with true positive C-reactive protein and/or interleukin-6 levels.

We conducted a multicentre cohort study of 228 patients with osteoarthritis followed up after total hip or knee replacement. Quality of life and patient satisfaction were assessed by self-administered questionnaires. Patient satisfaction was the dependent variable in a multivariate linear regression model. Independent variables included sociodemographic factors, pre- and post-operative clinical characteristics and the pre-operative and post-discharge health-related quality of life.

The mean age of the patients was 69 years (sd 9), and 43.8% were male. Pre- and postoperative clinical characteristics were not associated with satisfaction with health care. Only pre-operative bodily pain (p < 0.01) and pre-operative social functioning (p < 0.05) influenced patient satisfaction with care.

The pre-operative health-related quality of life and patient characteristics have little effect on inpatient satisfaction with care. This suggests that the impact of the care process on satisfaction may be independent of observed and perceived initial patient-related characteristics.

We carried out a blinded prospective randomised controlled trial comparing 2-octylcyanoacrylate (OCA), subcuticular suture (monocryl) and skin staples for skin closure following total hip and total knee arthroplasty. We included 102 hip replacements and 85 of the knee.

OCA was associated with less wound discharge in the first 24 hours for both the hip and the knee. However, with total knee replacement there was a trend for a more prolonged wound discharge with OCA. With total hip replacement there was no significant difference between the groups for either early or late complications. Closure of the wound with skin staples was significantly faster than with OCA or suture. There was no significant difference in the length of stay in hospital, Hollander wound evaluation score (cosmesis) or patient satisfaction between the groups at six weeks for either hips or knees.

We consider that skin staples are the skin closure of choice for both hip and knee replacements.

Implantation of allograft bone is an integral part of revision surgery of the hip. One major concern with its use is the risk of transmission of infective agents. There are a number of methods of processing allograft bone in order to reduce this risk. One method requires washing the tissue using pulsed irrigation immediately before implantation. We report the incidence of deep bacterial infection in 138 patients (144 revision hip arthroplasties) who had undergone implantation of allograft bone. The bone used was fresh-frozen, non-irradiated and pulse-washed with normal saline before implantation. The deep infection rate at a minimum follow-up of one year was 0.7%. This method of processing appears to be associated with a very low risk of allograft-related bacterial infection.

The routine use of surgical drains in total hip arthroplasty remains controversial. They have not been shown to decrease the rate of wound infection significantly and can provide a retrograde route for it. Their use does not reduce the size or incidence of post-operative wound haematomas. This prospective, randomised study was designed to evaluate the role of drains in routine total hip arthroplasty.

We investigated 552 patients (577 hips) undergoing unilateral or bilateral total hip arthroplasty who had been randomised to either having a drain for 24 hours or not having a drain. All patients followed standardised pre-, intra-, and post-operative regimes and were independently assessed using the Harris hip score before operation and at six, 18 and 36 months follow-up.

The rate of superficial and deep infection was 2.9% and 0.4%, respectively, in the drained group and 4.8% and 0.7%, respectively in the undrained group. One patient in the undrained group had a haematoma which did not require drainage or transfusion. The rate of transfusion after operation in the drained group was significantly higher than for undrained procedures (p < 0.042). The use of a drain did not influence the post-operative levels of haemoglobin, the revision rates, Harris hip scores, the length of hospital stay or the incidence of thromboembolism. We conclude that drains provide no clear advantage at total hip arthroplasty, represent an additional cost, and expose patients to a higher risk of transfusion.

We have investigated the contaminating bacteria in primary hip arthroplasty and their sensitivity to the prophylactic antibiotics currently in use. Impressions (627) of the gloved hands of the surgical team in 50 total hip arthroplasties were obtained on blood agar. The gloves were changed after draping, at intervals of 20 minutes thereafter, and before using cement. Changes were also undertaken whenever a visible puncture was detected. The culture plates were incubated at 37°C for 48 hours. Isolates were identified and tested for sensitivity to flucloxacillin, which is a recognised indicator of sensitivity to cefuroxime. They were also tested against other agents depending upon their appearance on Gram staining.

We found contamination in 57 (9%) impressions and 106 bacterial isolates. Coagulase-negative staphylococci were seen most frequently (68.9%), but we also isolated Micrococcus (12.3%), diphtheroids (9.4%), Staphylococcus aureus (6.6%) and Escherichia coli (0.9%). Of the coagulase-negative staphylococci, only 52.1% were sensitive to flucloxacillin and therefore to cefuroxime. We believe that it is now appropriate to review the relevance of prophylaxis with cefuroxime and to consider the use of other agents.

We wished to estimate the incidence of surgical-site infection (SSI) after total hip replacement (THR) and hemiarthroplasty and its strength of association with major risk factors. The SSI surveillance service prospectively gathered clinical, operative and infection data on inpatients from 102 hospitals in England during a four-year period.

The overall incidence of SSI was 2.23% for 16 291 THRs, 4.97% for 5769 hemiarthroplasty procedures, 3.68% for 2550 revision THRs and 7.6% for 198 revision hemiarthroplasties. Staphylococcus aureus was identified in 50% of SSIs; 59% of these isolates were methicillin-resistant (MRSA). In the single variable analysis of THRs, age, female gender, American Society of Anesthesiologists (ASA) score, body mass index, trauma, duration of operation and pre-operative stay were significantly associated with the risk of SSI (p < 0.05). For hemiarthroplasty, the ASA score and age were significant factors. In revision THRs male gender, ASA score, trauma, wound class, duration of operation and pre-operative stay were significant risk factors. The median time to detection of SSI was eight days for superficial incisional, 11 days for deep incisional and 11 days for joint/bone infections. For each procedure the mean length of stay doubled for patients with SSI. The multivariate analysis identified age group, trauma, duration of operation and ASA score as significant, independent risk factors for SSI. There was significant interhospital variation in the rates of SSI. MRSA was the most common pathogen to cause SSI in hip arthroplasty, especially in patients undergoing hemiarthroplasty, but coagulase-negative Staph. aureus may be more important in deep infections involving the joint.

We randomised 120 patients who were undergoing either primary total hip or knee arthroplasty to receive either ferrous sulphate or a placebo for three weeks after surgery. The level of haemoglobin and absolute reticulocyte count were measured at one and five days, and three and six weeks after operation. Ninety-nine patients (ferrous sulphate 50, placebo 49) completed the study. The two groups differed only in the treatment administered.

Recovery of level of haemoglobin was similar at five days and three weeks and returned to 85% of the pre-operative level, irrespective of the treatment group. A small, albeit greater recovery in the level of haemoglobin was identified at six weeks in the ferrous sulphate group in both men (ferrous sulphate 5%, placebo 1.5%) and women (ferrous sulphate 6%, placebo 3%). The clinical significance of this is questionable and may be outweighed by the high incidence of reported side effects of oral iron and the cost of the medication. Administration of iron supplements after elective total hip or total knee arthroplasty does not appear to be worthwhile.

After total hip (THR) or knee replacement (TKR), there is still an appreciable risk of developing deep-vein thrombosis despite prophylaxis with low-molecular-weight heparin (LMWH). In a prospective, randomised study we examined the efficacy of LMWH in combination with intermittent pneumatic compression in patients undergoing primary unilateral THR or TKR. We administered 40 mg of enoxaparin daily to 131 patients combined with either the use of intermittent pneumatic compression or the wearing of graduated compression stockings.

Compression ultrasonography showed no evidence of thrombosis after LMWH and intermittent pneumatic compression. In the group with LMWH and compression stockings the prevalence of thrombosis was 28.6% (40% after TKR, 14% after THR). This difference was significant (p < 0.0001). In the early post-operative phase after THR and TKR, combined prophylaxis with LMWH and intermittent pneumatic compression is more effective than LMWH used with graduated compression stockings.

Following total hip arthroplasty (THA) and total knee arthroplasty (TKR) only the ‘visible’ measured blood loss is usually known. This underestimates the ‘true’ total loss, as some loss is ‘hidden’. Correct management of blood loss should take hidden loss into account.

We studied 101 THAs and 101 TKAs (with re-infusion of drained blood). Following THA, the mean total loss was 1510 ml and the hidden loss 471 ml (26%). Following TKA, the mean total loss was 1498 ml. The hidden loss was 765 ml (49%). Obesity made no difference with either operation.

THA involves a small hidden loss, the total loss being 1.3 times that measured. However, following TKA, there may be substantial hidden blood loss due to bleeding into the tissues and residual blood in the joint. The true total loss can be determined by doubling the measured loss.

Fat embolism occurs following fractures of a long bone or arthroplasty. We investigated whether paradoxical embolisation through a venous-to-arterial circulation shunt (v-a) could lead to cerebral embolisation during elective hip or knee arthroplasty.

Transcranial Doppler ultrasound (TCD), following the intravenous injection of microbubble contrast, identified the presence of a shunt in 41 patients undergoing hip (n=20) or knee (n=21) arthroplasty. Intra-operative cerebral embolism was detected during continuous TCD monitoring. Of the 41 patients, 34 had a v-a shunt of whom 18 had an embolism and embolism only occurred in patients with a shunt (p = 0.012). Spontaneous and larger shunts were associated with a greater number of emboli (r_s = 0.67 and r_s = 0.71 respectively, p < 0.01). Observations in two patients with large spontaneous shunts revealed 368 and 203 emboli and unexplained post-operative confusion and pancreatitis.

Paradoxical cerebral embolisation only occurred in patients with a shunt and may explain both postoperative confusion and fat embolism syndrome following surgery.

The aim of this study was to determine the prevalence of deep venous thrombosis (DVT) following lower limb arthroplasty and to assess whether this adversely affected satisfaction, relief from pain, or the level of mobility as perceived by patients. Six hundred and ten consecutive recipients of primary total hip replacement (THR) or total knee replacement (TKR) underwent routine post-operative venography. The functional outcome had already been assessed at one year by using the Regional Arthroplasty Database questionnaire, the results of which were correlated to venographic records.

The combined prevalence of DVT after THR and TKR in the patients, who did not receive chemical thromboprophylaxis, was 46.4%. Thrombus was identified in 57.6% of those with a TKR and in 33.5% of patients with a THR. Proximal thrombus was found in 11.0% of TKRs and in 14.8% of THRs. One year after surgery, patients who had a DVT established by venography did not report higher levels of immobility (p = 0.07), discomfort (p = 0.12) or dissatisfaction (p = 0.23) when compared to those with patent venous systems.

This suggests that the prevalence of DVT following TKR/THR without chemical thromboprophylaxis is high and these findings are consistent with the literature. However, patients did not perceive thrombosis to compromise their overall outcome. This challenges the belief that DVT is associated with morbidity and calls for further comprehensive research in this area. The low morbidity of the lower limb associated with DVT in these patients does not support the use of chemical thromboprophylaxis.

We used prospective data from 862 total knee and 716 total hip replacements three years after surgery in order to derive and validate a reduced Western Ontario and McMasters University Osteoarthritis Index (WOMAC) function scale. The reduced scale was derived using the advice of clinical experts as well as analysis of data. The scale was tested for validity, reliability and responsiveness.

Items which were retained included: ascending stairs, rising from sitting, walking on the flat, getting in or out of a car, putting on socks, rising from bed, and sitting.

The reduced and full scales had comparable, moderate correlations with other measures of function, confirming convergent validity. Cronbach’s alpha was high (α > 0.85) with the reduced scale confirming reliability. Responsiveness was greater for the reduced scale (full = 1.4, reduced = 1.6).

This reduced version of the WOMAC function scale provides a practical, valid, reliable and responsive alternative to the full function scale for use after total joint replacement. Further work is needed to demonstrate its wider applicability.

There has been speculation as to how the outcome of revision total knee arthroplasty (TKA) compares with that of primary TKA. We have collected data prospectively from patients operated on by one surgeon using one prosthesis in each group. One hundred patients underwent primary TKA and 60 revision TKA. They completed SF-12 and WOMAC questionnaires before and at six and 12 months after operation.

The improvements in the SF-12 physical scores and WOMAC pain, stiffness and function scores in both primary and revision TKA patients were highly statistically significant at six months. There was no statistically significant difference in the size of the improvement in the SF-12 physical and WOMAC pain, stiffness and function scores between the primary and revision patients at six months after surgery. The SF-12 mental scores of patients in both groups showed no statistically significant difference after surgery at the six- and 12-month assessments.

Our findings show that primary and revision TKA lead to a comparable improvement in patient-perceived outcomes of physical variables in both generic and disease-specific health measures at follow-up at one year.

Residual pain after total hip due to a number of causes both local to and replacement may be distant from the hip. We describe pain related to the psoas muscle after total hip replacement in nine patients. All presented with characteristic symptoms. We describe the key features and management. Gratifying results were achieved with treatment. This diagnosis should be considered when assessing patients with pain after total hip replacement.

We report the mid-term results of femoral impaction grafting which was used in 53 patients during the second stage of a two-stage revision for an infected total hip replacement. We reviewed all cases performed between 1989 and 1998. All patients underwent a Girdlestone excision arthroplasty, received local and systemic antibiotics and subsequently underwent reconstruction, using femoral impaction grafting.

Four patients had further infection (7.5%), and four died within 24 months of surgery. One patient underwent revision of the stem for a fracture below its tip at ten months. This left 44 patients with a mean follow-up of 53 months (24 to 122). All had improved clinical scores and a satisfactory radiological outcome.