Whether patients with asymptomatic bacteriuria should be investigated and treated before elective hip and knee replacement is controversial, although it is a widespread practice. We conducted a prospective observational cohort study with urine analyses before surgery and three days post-operatively. Patients with symptomatic urinary infections or an indwelling catheter were excluded. Post-discharge surveillance included questionnaires to patients and general practitioners at three months. Among 510 patients (309 women and 201 men), with a median age of 69 years (16 to 97) undergoing lower limb joint replacements (290 hips and 220 knees), 182 (36%) had pre-operative asymptomatic bacteriuria, mostly due to Escherichia coli, and 181 (35%) had white cells in the urine. Most patients (95%) received a single intravenous peri-operative dose (1.5 g) of cefuroxime as prophylaxis. On the third post-operative day urinary analysis identified white cells in 99 samples (19%) and bacteriuria in 208 (41%). Pathogens in the cultures on the third post-operative day were different from those in the pre-operative samples in 260 patients (51%). Only 25 patients (5%) developed a symptomatic urinary infection during their stay or in a subsequent three-month follow-up period, and two thirds of organisms identified were unrelated to those found during the admission. All symptomatic infections were successfully treated with oral antibiotics with no perceived effect on the joint replacement.

We conclude that testing and treating asymptomatic urinary tract colonisation before joint replacement is unnecessary.

Cite this article: Bone Joint J 2014;96-B:390–4.

We reviewed the outcome of 69 uncemented, custom-made, distal femoral endoprosthetic replacements performed in 69 patients between 1994 and 2006. There were 31 women and 38 men with a mean age at implantation of 16.5 years (5 to 37). All procedures were performed for primary malignant bone tumours of the distal femur. At a mean follow-up of 124.2 months (4 to 212), 53 patients were alive, with one patient lost to follow-up. All nine implants (13.0%) were revised due to aseptic loosening at a mean of 52 months (8 to 91); three implants (4.3%) were revised due to fracture of the shaft of the prosthesis and three patients (4.3%) had a peri-prosthetic fracture. Bone remodelling associated with periosteal cortical thinning adjacent to the uncemented intramedullary stem was seen in 24 patients but this did not predispose to failure. All aseptically loose implants in this series were diagnosed to be loose within the first five years.

The results from this study suggest that custom-made uncemented distal femur replacements have a higher rate of aseptic loosening compared to published results for this design when used with cemented fixation. Loosening of uncemented replacements occurs early indicating that initial fixation of the implant is crucial.

Cite this article: Bone Joint J 2014;96-B:263–9.

Since the introduction of the National Institute for Health and Care Excellence (NICE) guidelines on thromboprophylaxis and the use of extended thromboprophylaxis with new oral agents, there have been reports of complications arising as a result of their use. We have looked at the incidence of wound complications after the introduction of dabigatran for thromboprophylaxis in our unit.

We investigated the rate of venous thromboembolism and wound leakage in 1728 patients undergoing primary joint replacement, both before and after the introduction of dabigatran, and following its subsequent withdrawal from our unit.

We found that the use of dabigatran led to a significant increase in post-operative wound leakage (20% with dabigatran, 5% with a multimodal regimen; p < 0.001), which also resulted in an increased duration of hospital stay. The rate of thromboembolism in patients receiving dabigatran was higher (1.3%) than in those receiving the multimodal thromboprophylaxis regimen, including low molecular weight heparin as an inpatient and the extended use of aspirin (0.3%, p = 0.047). We have ceased the use of dabigatran for thromboprophylaxis in these patients.

Cite this article: Bone Joint J 2014;96-B:122–6.

In our department we use an enhanced recovery protocol for joint replacement of the lower limb. This incorporates the use of intravenous tranexamic acid (IVTA; 15 mg/kg) at the induction of anaesthesia. Recently there was a national shortage of IVTA for 18 weeks; during this period all patients received an oral preparation of tranexamic acid (OTA; 25 mg/kg). This retrospective study compares the safety (surgical and medical complications) and efficacy (reduction of transfusion requirements) of OTA and IVTA. During the study period a total of 2698 patients received IVTA and 302 received OTA. After adjusting for a range of patient and surgical factors, the odds ratio (OR) of receiving a blood transfusion was significantly higher with IVTA than with OTA (OR 0.48 (95% confidence interval 0.26 to 0.89), p = 0.019), whereas the safety profile was similar, based on length of stay, rate of readmission, return to theatre, deep infection, stroke, gastrointestinal bleeding, myocardial infarction, pneumonia, deep-vein thrombosis and pulmonary embolism. The financial benefit of OTA is £2.04 for a 70 kg patient; this is amplified when the cost saving associated with significantly fewer blood transfusions is considered.

Although the number of patients in the study is modest, this work supports the use of OTA, and we recommend that a randomised trial be undertaken to compare the different methods of administering tranexamic acid.

Cite this article: Bone Joint J 2013;95-B:1556–61.

The aim of this study was to evaluate whether coating titanium discs with selenium in the form of sodium selenite decreased bacterial adhesion of Staphylococcus aureus and Staph. epidermidis and impeded osteoblastic cell growth.

In order to evaluate bacterial adhesion, sterile titanium discs were coated with increasing concentrations of selenium and incubated with bacterial solutions of Staph. aureus (ATCC 29213) and Staph. epidermidis (DSM 3269) and stained with Safranin-O. The effect of selenium on osteoblastic cell growth was also observed. The adherence of MG-63 cells on the coated discs was detected by staining with Safranin-O. The proportion of covered area was calculated with imaging software.

The tested Staph. aureus strain showed a significantly reduced attachment on titanium discs with 0.5% (p = 0.011) and 0.2% (p = 0.02) selenium coating. Our test strain from Staph. epidermidis showed a highly significant reduction in bacterial adherence on discs coated with 0.5% (p = 0.0099) and 0.2% (p = 0.002) selenium solution. There was no inhibitory effect of the selenium coating on the osteoblastic cell growth.

Selenium coating is a promising method to reduce bacterial attachment on prosthetic material.

Cite this article: Bone Joint J 2013;95-B:678–82.

Cut-off values with highest sensitivity and specificity for the synovial fluid white cell and differential count will facilitate the accurate diagnosis of infection in total knee (TKR) and total hip replacement (THR). All patients undergoing revision TKR or THR for suspected prosthetic joint infection between 2009 and 2011 at two hospitals were identified. A total of 75 patients were included with a mean age of 70.3 years (38 to 89). Synovial fluid was aspirated pre-operatively and peri-prosthetic tissue samples were taken intra-operatively for histological and microbiological examination.

Receiver operating characteristic (ROC) plots were constructed for white cell and differential counts in aspirated fluid. The optimal cut-off for TKR and THR was 1590 white cells/µl and 65% neutrophilia. The white cell count cut-off value identified for THR was notably lower than previously quoted in the literature. A cut-off value for white cell count in synovial aspirate in suspected prosthetic joint infection of between 1100 and 1700 white cells/µl is likely to be applicable to both THR and TKR.

Cite this article: Bone Joint J 2013;95-B:554–7.

We have recently shown that waste heat from forced-air warming blankets can increase the temperature and concentration of airborne particles over the surgical site. The mechanism for the increased concentration of particles and their site of origin remained unclear. We therefore attempted to visualise the airflow in theatre over a simulated total knee replacement using neutral-buoyancy helium bubbles. Particles were created using a Rocket PS23 smoke machine positioned below the operating table, a potential area of contamination. The same theatre set-up, warming devices and controls were used as in our previous study. This demonstrated that waste heat from the poorly insulated forced-air warming blanket increased the air temperature on the surgical side of the drape by > 5°C. This created convection currents that rose against the downward unidirectional airflow, causing turbulence over the patient. The convection currents increased the particle concentration 1000-fold (2 174 000 particles/m³ for forced-air warming vs 1000 particles/m³ for radiant warming and 2000 particles/m³ for the control) by drawing potentially contaminated particles from below the operating table into the surgical site.

Cite this article: Bone Joint J 2013;95-B:407–10.

Although the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index was originally developed for the assessment of non-operative treatment, it is commonly used to evaluate patients undergoing either total hip (THR) or total knee replacement (TKR). We assessed the importance of the 17 WOMAC function items from the perspective of 1198 patients who underwent either THR (n = 704) or TKR (n = 494) in order to develop joint-specific short forms. After these patients were administered the WOMAC pre-operatively and at three, six, 12 and 24 months’ follow-up, they were asked to nominate an item of the function scale that was most important to them. The items chosen were significantly different between patients undergoing THR and those undergoing TKR (p < 0.001), and there was a shift in the priorities after surgery in both groups. Setting a threshold for prioritised items of ≥ 5% across all follow-up, eight items were selected for THR and seven for TKR, of which six items were common to both. The items comprising specific WOMAC-THR and TKR function short forms were found to be equally responsive compared with the original WOMAC function form.

Cite this article: Bone Joint J 2013;95-B:239–43.

The purpose of this study was to compare the diagnostic accuracy for the detection of infection between the culture of fluid obtained by sonication (SFC) and the culture of peri-implant tissues (PITC) in patients with early and delayed implant failure, and those with unsuspected and suspected septic failure. It was hypothesised that SFC increases the diagnostic accuracy for infection in delayed, but not early, implant failure, and in unsuspected septic failure. The diagnostic accuracy for infection of all consecutive implants (hardware or prostheses) that were removed for failure was compared between SFC and PITC. This prospective study included 317 patients with a mean age of 62.7 years (9 to 97). The sensitivity for detection of infection using SFC was higher than using PITC in an overall comparison (89.9% versus 67%, respectively; p < 0.001), in unsuspected septic failure (100% versus 48.5%, respectively; p < 0.001), and in delayed implant failure (88% versus 58%, respectively; p < 0.001). PITC sensitivity dropped significantly in unsuspected compared with suspected septic failure (p = 0.007), and in delayed compared with early failure (p = 0.013). There were no differences in specificity.

Sonication is mainly recommended when there is implant failure with no clear signs of infection and in patients with delayed implant failure. In early failure, SFC is not superior to PITC for the diagnosis of infection and, therefore, is not recommended as a routine diagnostic test in these patients.

Cite this article: Bone Joint J 2013;95-B:244–9.

The results of hip and knee replacement surgery are generally regarded as positive for patients. Nonetheless, they are both major operations and have recognised complications. We present a review of relevant claims made to the National Health Service Litigation Authority. Between 1995 and 2010 there were 1004 claims to a value of £41.5 million following hip replacement surgery and 523 claims to a value of £21 million for knee replacement. The most common complaint after hip surgery was related to residual neurological deficit, whereas after knee replacement it was related to infection. Vascular complications resulted in the highest costs per case in each group.

Although there has been a large increase in the number of operations performed, there has not been a corresponding relative increase in litigation. The reasons for litigation have remained largely unchanged over time after hip replacement. In the case of knee replacement, although there has been a reduction in claims for infection, there has been an increase in claims for technical errors. There has also been a rise in claims for non-specified dissatisfaction. This information is of value to surgeons and can be used to minimise the potential mismatch between patient expectation, informed consent and outcome.

Cite this article: Bone Joint J 2013;95-B:122–6.

The aim of this study was to perform a cost–utility analysis of total hip (THR) and knee replacement (TKR). Arthritis is a disabling condition that leads to long-term deterioration in quality of life. Total joint replacement, despite being one of the greatest advances in medicine of the modern era, has recently come under scrutiny. The National Health Service (NHS) has competing demands, and resource allocation is challenging in times of economic restraint. Patients who underwent THR (n = 348) or TKR (n = 323) between January and July 2010 in one Scottish region were entered into a prospective arthroplasty database. A health–utility score was derived from the EuroQol (EQ-5D) score pre-operatively and at one year, and was combined with individual life expectancy to derive the quality-adjusted life years (QALYs) gained. Two-way analysis of variance was used to compare QALYs gained between procedures, while controlling for baseline differences. The number of QALYs gained was higher after THR than after TKR (6.5 vs 4.0 years, p < 0.001). The cost per QALY for THR was £1372 compared with £2101 for TKR. The predictors of an increase in QALYs gained were poorer health before surgery (p < 0.001) and younger age (p < 0.001). General health (EQ-5D VAS) showed greater improvement after THR than after TKR (p < 0.001). This study provides up-to-date cost-effectiveness data for total joint replacement. THR and TKR are extremely effective both clinically and in terms of cost effectiveness, with costs that compare favourably to those of other medical interventions.

Cite this article: Bone Joint J 2013;95-B:115–21.

Post-operative complications after total hip or knee replacement can delay recovery, prolong hospitalisation, increase rates of re-admission and, in the most severe cases, lead to long-term disability or even death. In this analysis of pooled data from four large, randomised, phase III clinical trials that compared the oral, direct Factor Xa inhibitor rivaroxaban with subcutaneous enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement (n = 12 729), the incidence of complications, including bleeding and adverse events related to surgery (such as wound infection, wound dehiscence and haemarthrosis) are reported. Interventions and procedures relating to surgery are also compared between the groups. Bleeding events, including excessive wound haematoma and surgical-site bleeding, occurred at similar rates in the rivaroxaban and enoxaparin groups. Over the total study duration, adverse surgical events occurred at a similar rate in the rivaroxaban group compared with the enoxaparin group after total knee replacement (2.26% vs 2.69%, respectively) and total hip replacement (1.48% vs 1.65%, respectively). Blood loss, wound drainage and transfusion requirements were also similar between the two groups.

This analysis shows that the incidence of adverse surgical events with rivaroxaban was similar to enoxaparin.

Obtaining a balanced flexion gap with correct femoral component rotation is one of the prerequisites for a successful outcome after total knee replacement (TKR). Different techniques for achieving this have been described. In this study we prospectively compared gap-balancing versus measured resection in terms of reliability and accuracy for femoral component rotation in 96 primary TKRs performed in 96 patients using the Journey system. In 48 patients (18 men and 30 women) with a mean age of 65 years (45 to 85) a tensor device was used to determine rotation. In the second group of 48 patients (14 men and 34 women) with a mean age of 64 years (41 to 86), an ‘adapted’ measured resection technique was used, taking into account the native rotational geometry of the femur as measured on a pre-operative CT scan.

Both groups systematically reproduced a similar external rotation of the femoral component relative to the surgical transepicondylar axis: 2.4° (sd 2.5) in the gap-balancing group and 1.7° (sd 2.1) in the measured resection group (p = 0.134). Both gap-balancing and adapted measured resection techniques proved equally reliable and accurate in determining femoral component rotation after TKR. There was a tendency towards more external rotation in the gap-balancing group, but this difference was not statistically significant (p = 0.134). The number of outliers for our ‘adapted’ measured resection technique was much lower than reported in the literature.

Using general practitioner records and hospital notes and through direct telephone conversation with patients, we investigated the accuracy of nine patient-reported complications gathered from a self-completed questionnaire after elective joint replacement surgery of the hip and knee. A total of 402 post-discharge complications were reported after 8546 elective operations that were undertaken within a three-year period. These were reported by 136 men and 240 women with a mean age of 71.8 years (34 to 93). A total of 319 reported complications (79.4%; 95% confidence interval 75.4 to 83.3) were confirmed to be correct. High rates of correct reporting were demonstrated for infection (94.5%) and the need for further surgery (100%), whereas the rates of reporting deep-vein thrombosis (DVT), pulmonary embolism, myocardial infarction and stroke were lower (75% to 84.2%). Dislocation, peri-prosthetic fractures and nerve palsy had modest rates of correct reporting (36% to 57.1%). More patients who had knee surgery delivered incorrect reports of dislocation (p = 0.001) and DVT (p = 0.013).

Despite these variations, it appears that post-operative complications may form part of a larger patient-reported outcome programme after elective joint replacement surgery.

We report a systematic review and meta-analysis of the peer-reviewed literature focusing on metal sensitivity testing in patients undergoing total joint replacement (TJR). Our purpose was to assess the risk of developing metal hypersensitivity post-operatively and its relationship with outcome and to investigate the advantages of performing hypersensitivity testing.

We undertook a comprehensive search of the citations quoted in PubMed and EMBASE: 22 articles (comprising 3634 patients) met the inclusion criteria. The frequency of positive tests increased after TJR, especially in patients with implant failure or a metal-on-metal coupling. The probability of developing a metal allergy was higher post-operatively (odds ratio (OR) 1.52 (95% confidence interval (CI) 1.06 to 2.31)), and the risk was further increased when failed implants were compared with stable TJRs (OR 2.76 (95% CI 1.14 to 6.70)).

Hypersensitivity testing was not able to discriminate between stable and failed TJRs, as its predictive value was not statistically proven. However, it is generally thought that hypersensitivity testing should be performed in patients with a history of metal allergy and in failed TJRs, especially with metal-on-metal implants and when the cause of the loosening is doubtful.

Patient expectations and their fulfilment are an important factor in determining patient-reported outcome and satisfaction of hip (THR) and knee replacement (TKR). The aim of this prospective cohort study was to examine the expectations of patients undergoing THR and TKR, and to identify differences in expectations, predictors of high expectations and the relationship between the fulfilment of expectations and patient-reported outcome measures. During the study period, patients who underwent 346 THRs and 323 TKRs completed an expectation questionnaire, Oxford score and Short-Form 12 (SF-12) score pre-operatively. At one year post-operatively, the Oxford score, SF-12, patient satisfaction and expectation fulfilment were assessed. Univariable and multivariable analysis were performed. Improvements in mobility and daytime pain were the most important expectations in both groups. Expectation level did not differ between THR and TKR. Poor Oxford score, younger age and male gender significantly predicted high pre-operative expectations (p < 0.001). The level of pre-operative expectation was not significantly associated with the fulfilment of expectations or outcome. THR better met the expectations identified as important by patients. TKR failed to meet expectations of kneeling, squatting and stair climbing. High fulfilment of expectation in both THR and TKR was significantly predicted by young age, greater improvements in Oxford score and high pre-operative mental health scores. The fulfilment of expectations was highly correlated with satisfaction.

We obtained information from the Elective Orthopaedic Centre on 1523 patients with baseline and six-month Oxford hip scores (OHS) after undergoing primary hip replacement (THR) and 1784 patients with Oxford knee scores (OKS) for primary knee replacement (TKR) who completed a six-month satisfaction questionnaire.

Receiver operating characteristic curves identified an absolute change in OHS of 14 points or more as the point that discriminates best between patients’ satisfaction levels and an 11-point change for the OKS. Satisfaction is highest (97.6%) in patients with an absolute change in OHS of 14 points or more, compared with lower levels of satisfaction (81.8%) below this threshold. Similarly, an 11-point absolute change in OKS was associated with 95.4% satisfaction compared with 76.5% below this threshold. For the six-month OHS a score of 35 points or more distinguished patients with the highest satisfaction level, and for the six-month OKS 30 points or more identified the highest level of satisfaction. The thresholds varied according to patients’ pre-operative score, where those with severe pre-operative pain/function required a lower six-month score to achieve the highest levels of satisfaction.

Our data suggest that the choice of a six-month follow-up to assess patient-reported outcomes of THR/TKR is acceptable. The thresholds help to differentiate between patients with different levels of satisfaction, but external validation will be required prior to general implementation in clinical practice.

In order to compare the effect of oral apixaban (a factor Xa inhibitor) with subcutaneous enoxaparin on major venous thromboembolism and major and non-major clinically relevant bleeding after total knee and hip replacement, we conducted a pooled analysis of two previously reported double-blind randomised studies involving 8464 patients. One group received apixaban 2.5 mg twice daily (plus placebo injection) starting 12 to 24 hours after operation, and the other received enoxaparin subcutaneously once daily (and placebo tablets) starting 12 hours (± 3) pre-operatively. Each regimen was continued for 12 days (± 2) after knee and 35 days (± 3) after hip arthroplasty. All outcomes were centrally adjudicated. Major venous thromboembolism occurred in 23 of 3394 (0.7%) evaluable apixaban patients and in 51 of 3394 (1.5%) evaluable enoxaparin patients (risk difference, apixaban minus enoxaparin, -0.8% (95% confidence interval (CI) -1.2 to -0.3); two-sided p = 0.001 for superiority). Major bleeding occurred in 31 of 4174 (0.7%) apixaban patients and 32 of 4167 (0.8%) enoxaparin patients (risk difference -0.02% (95% CI -0.4 to 0.4)). Combined major and clinically relevant non-major bleeding occurred in 182 (4.4%) apixaban patients and 206 (4.9%) enoxaparin patients (risk difference -0.6% (95% CI -1.5 to 0.3)).

Apixaban 2.5 mg twice daily is more effective than enoxaparin 40 mg once daily without increased bleeding.

Patients with infected arthroplasties are normally treated with a two-stage exchange procedure using polymethylmethacrylate bone cement spacers impregnated with antibiotics. However, spacers may act as a foreign body to which micro-organisms may adhere and grow. In this study it was hypothesised that subclinical infection may be diagnosed with sonication of the surface biofilm of the spacer. The aims were to assess the presence of subclinical infection through sonication of the spacer at the time of a second-stage procedure, and to determine the relationship between subclinical infection and the clinical outcome. Of 55 patients studied, 11 (20%) were diagnosed with subclinical infection. At a mean follow-up of 12 months (interquartile range 6 to 18), clinical failure was found in 18 (32.7%) patients. Of the patients previously diagnosed with subclinical infection, 63% (7 of 11) had failed compared with 25% (11 of 44) of those without subclinical infection (odds ratio 5.25, 95% confidence interval 1.29 to 21.4, p = 0.021). Sonication of the biofilm of the surface of the spacer is useful in order to exclude subclinical infection and therefore contributes to improving the outcome after two-stage procedures.

Patient warming significantly decreases the risk of surgical site infection. Recently there have been concerns that forced air warming may interfere with unidirectional airflow, potentially posing an increased risk of infection. Our null hypothesis was that forced air and radiant warming devices do not increase the temperature and the number of particles over the surgical site when compared with no warming device. A forced air warming device was compared with a radiant warming device and no warming device as a control. The temperature and number of particles were measured over the surgical site. The theatre was prepared as for a routine lower-limb arthroplasty operation, and the same volunteer was used throughout the study.

Forced air warming resulted in a significant mean increase in the temperature (1.1°C vs 0.4°C, p < 0.0001) and number of particles (1038.2 vs 274.8, p = 0.0087) over the surgical site when compared with radiant warming, which raises concern as bacteria are known to require particles for transport.