Aims

The use of technology to assess balance and alignment during total knee surgery can provide an overload of numerical data to the surgeon. Meanwhile, this quantification holds the potential to clarify and guide the surgeon through the surgical decision process when selecting the appropriate bone recut or soft tissue adjustment when balancing a total knee. Therefore, this paper evaluates the potential of deploying supervised machine learning (ML) models to select a surgical correction based on patient-specific intra-operative assessments.

We present seven patients with recurrent haemarthroses after total knee arthroplasty, caused by an inherent platelet function defect. These patients developed painful knee swelling, persistent bleeding and/or wound breakdown, a platelet factor 3 availability defect being identified in all cases. Surgical exploration, with joint debridement, lavage and synovectomy, was performed in four patients who did not improve with conservative therapy. Histopathological examination of synovium revealed a focal synovial reaction with histiocytic infiltration, and occasional foreign-body giant cells. One patient required an early revision because of aseptic loosening of their tibial component. The condition was treated by single-donor platelet transfusions with good results. The diagnosis, management, and relevance of this disorder are discussed

Aims. Currently, there is no single, comprehensive national guideline for analgesic strategies for total joint replacement. We compared inpatient and outpatient opioid requirements following total hip arthroplasty (THA) versus total knee arthroplasty (TKA) in order to determine risk factors for increased inpatient and outpatient opioid requirements following total hip or knee arthroplasty. Methods. Outcomes after 92 primary total knee (n = 49) and hip (n = 43) arthroplasties were analyzed. Patients with repeat surgery within 90 days were excluded. Opioid use was recorded while inpatient and 90 days postoperatively. Outcomes included total opioid use, refills, use beyond 90 days, and unplanned clinical encounters for uncontrolled pain. Multivariate modelling determined the effect of surgery, regional nerve block (RNB) or neuraxial anesthesia (NA), and non-opioid medications after adjusting for demographics, ength of stay, and baseline opioid use. Results. TKAs had higher daily inpatient opioid use than THAs (in 5 mg oxycodone pill equivalents: median 12.0 vs 7.0; p < 0.001), and greater 90 day use (median 224.0 vs 100.5; p < 0.001). Opioid refills were more likely in TKA (84% vs 33%; p < 0.001). Patient who underwent TKA had higher independent risk of opioid use beyond 90 days than THA (adjusted OR 7.64; 95% SE 1.23 to 47.5; p = 0.01). Inpatient opioid use 24 hours before discharge was the strongest independent predictor of 90-day opioid use (p < 0.001). Surgical procedure, demographics, and baseline opioid use have greater influence on in/outpatient opioid demand than RNB, NA, or non-opioid analgesics. Conclusion. Opioid use following TKA and THA is most strongly predicted by surgical and patient factors. TKA was associated with higher postoperative opioid requirements than THA. RNB and NA did not diminish total inpatient or 90-day postoperative opioid consumption. The use of acetaminophen, gabapentin, or NSAIDs did not significantly alter inpatient opioid requirements. Cite this article: Bone Joint Open 2020;1-7:398–404

Aims. The aim of this study was to determine the impact of the severity of anaemia on postoperative complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA). Methods. A retrospective cohort study was conducted using the American College of Surgeons National Quality Improvement Program (ACS-NSQIP) database. All patients who underwent primary TKA or THA between January 2012 and December 2017 were identified and stratified based upon hematocrit level. In this analysis, we defined anaemia as packed cell volume (Hct) < 36% for women and < 39% for men, and further stratified anaemia as mild anaemia (Hct 33% to 36% for women, Hct 33% to 39% for men), and moderate to severe (Hct < 33% for both men and women). Univariate and multivariate analyses were used to evaluate the incidence of multiple adverse events within 30 days of arthroplasty. Results. Following adjustment, patients in the THA cohort with moderate to severe anaemia had an increased odds of 6.194 (95% confidence interval (CI) 5.679 to 6.756; p < 0.001) for developing any postoperative complication. Following adjustment, patients in the TKA cohort with moderate to severe anaemia had an increased odds of 5.186 (95% CI 4.811 to 5.590; p < 0.001) for developing any postoperative complication. Among both cohorts, as severity increased, there was an increased risk of postoperative complications. Conclusion. Preoperative anaemia is a risk factor for complications following primary arthroplasty. There is a significant relationship between the severity of anaemia and the odds of postoperative complications. Patients who had moderate to severe anaemia were at increased risk of developing postoperative complications relative to patients with mild anaemia. When considering elective primary THA or TKA in a moderately or severely anaemic patient, surgeons should strongly consider correcting anaemia prior to surgery if possible. Cite this article: Bone Joint J 2020;102-B(4):485–494

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This study aimed to investigate the risk of postoperative complications in COVID-19-positive patients undergoing common orthopaedic procedures.

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In the UK, the NHS generates an estimated 25 megatonnes of carbon dioxide equivalents (4% to 5% of the nation’s total carbon emissions) and produces over 500,000 tonnes of waste annually. There is limited evidence demonstrating the principles of sustainability and its benefits within orthopaedic surgery. The primary aim of this study was to analyze the environmental impact of orthopaedic surgery and the environmentally sustainable initiatives undertaken to address this. The secondary aim of this study was to describe the barriers to making sustainable changes within orthopaedic surgery.

Aims

Delayed postoperative inoculation of orthopaedic implants with persistent wound drainage or bacterial seeding of a haematoma can result in periprosthetic joint infection (PJI). The aim of this in vivo study was to compare the efficacy of vancomycin powder with vancomycin-eluting calcium sulphate beads in preventing PJI due to delayed inoculation.

Aims

Our primary aim was to establish the proportion of female orthopaedic consultants who perform arthroplasty via cases submitted to the National Joint Registry (NJR), which covers England, Wales, Northern Ireland, the Isle of Man, and Guernsey. Secondary aims included comparing time since specialist registration, private practice participation, and number of hospitals worked in between male and female surgeons.

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The COVID-19 pandemic drastically affected elective orthopaedic services globally as routine orthopaedic activity was largely halted to combat this global threat. Our institution (University College London Hospital, UK) previously showed that during the first peak, a large proportion of patients were hesitant to be listed for their elective lower limb procedure. The aim of this study is to assess if there is a patient perception change towards having elective surgery now that we have passed the peak of the second wave of the pandemic.

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The aim of this study was to surveil whether the standard operating procedure created for the NHS Golden Jubilee sufficiently managed COVID-19 risk to allow safe resumption of elective orthopaedic surgery.

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There is little published on the outcomes after restarting elective orthopaedic procedures following cessation of surgery due to the COVID-19 pandemic. During the pandemic, the reported perioperative mortality in patients who acquired SARS-CoV-2 infection while undergoing elective orthopaedic surgery was 18% to 20%. The aim of this study is to report the surgical outcomes, complications, and risk of developing COVID-19 in 2,316 consecutive patients who underwent elective orthopaedic surgery in the latter part of 2020 and comparing it to the same, pre-pandemic, period in 2019.

Aims

Orthopaedic surgeries are complex, frequently performed procedures associated with significant haemorrhage and perioperative blood transfusion. Given refinements in surgical techniques and changes to transfusion practices, we aim to describe contemporary transfusion practices in orthopaedic surgery in order to inform perioperative planning and blood banking requirements.

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Orthopaedic infection is a potentially serious complication of elective and emergency trauma and orthopaedic procedures, with a high associated burden of morbidity and cost. Optimization of vitamin D levels has been postulated to be beneficial in the prevention of orthopaedic infection. This study explores the role of vitamin D in orthopaedic infection through a systematic review of available evidence.

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The primary aim is to estimate the current and potential number of patients on NHS England orthopaedic elective waiting lists by November 2020. The secondary aims are to model recovery strategies; review the deficit of hip and knee arthroplasty from National Joint Registry (NJR) data; and assess the cost of returning to pre-COVID-19 waiting list numbers.

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The primary aim of this study was to assess the independent association of the coronavirus disease 2019 (COVID-19) on postoperative mortality for patients undergoing orthopaedic and trauma surgery. The secondary aim was to identify factors that were associated with developing COVID-19 during the postoperative period.

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The risk to patients and healthcare workers of resuming elective orthopaedic surgery following the peak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has been difficult to quantify. This has prompted governing bodies to adopt a cautious approach that may be impractical and financially unsustainable. The lack of evidence has made it impossible for surgeons to give patients an informed perspective of the consequences of elective surgery in the presence of SARS-CoV-2. This study aims to determine, for the UK population, the probability of a patient being admitted with an undetected SARS-CoV-2 infection and their resulting risk of death; taking into consideration the current disease prevalence, reverse transcription-polymerase chain reaction (RT-PCR) testing, and preassessment pathway.

Aims

The safe resumption of elective orthopaedic surgery following the peak of the COVID-19 pandemic remains a significant challenge. A number of institutions have developed a COVID-free pathway for elective surgery patients in order to minimize the risk of viral transmission. The aim of this study is to identify the perioperative viral transmission rate in elective orthopaedic patients following the restart of elective surgery.

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The aim of this study was to characterize the relationship between pre- and postoperative opioid use among patients undergoing common elective orthopaedic procedures

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To evaluate safety outcomes and patient satisfaction of the re-introduction of elective orthopaedic surgery on ‘green’ (non-COVID-19) sites during the COVID-19 pandemic.

Over a 13-year period we studied all patients who underwent major hip and knee surgery and were diagnosed with objectively confirmed symptomatic venous thromboembolism, either deep venous thrombosis or non-fatal pulmonary embolism, within six months after surgery. Low-molecular-weight heparin had been given while the patients were in hospital. There were 5607 patients. The cumulative incidence of symptomatic venous thromboembolism was 2.7% (150 of 5607), of which 1.1% had developed pulmonary embolism, 1.5% had deep venous thrombosis and 0.6% had both. Patients presented with deep venous thrombosis at a median of 24 days and pulmonary embolism at 17 days after surgery for hip fracture. After total hip replacement, deep venous thrombosis and pulmonary embolism occurred at a median of 21 and 34 days respectively. After total knee replacement, the median time to the presentation of deep venous thrombosis and pulmonary embolism was 20 and 12 days respectively. The cumulative risk of venous thromboembolism lasted for up to three months after hip surgery and for one month after total knee replacement. Venous thromboembolism was diagnosed after discharge from hospital in 70% of patients who developed this complication. Despite hospital-based thromboprophylaxis, most cases of clinical venous thromboembolism occur after discharge and at different times according to the operation performed

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Medical comorbidities are a critical factor in the decision-making process for operative management and risk-stratification. The Hierarchical Condition Categories (HCC) risk adjustment model is a powerful measure of illness severity for patients treated by surgeons. The HCC is utilized by Medicare to predict medical expenditure risk and to reimburse physicians accordingly. HCC weighs comorbidities differently to calculate risk. This study determines the prevalence of medical comorbidities and the average HCC score in Medicare patients being evaluated by neurosurgeons and orthopaedic surgeon, as well as a subset of academic spine surgeons within both specialities, in the USA.

Aims

As the peak of the COVID-19 pandemic passes, the challenge shifts to safe resumption of routine medical services, including elective orthopaedic surgery. Protocols including pre-operative self-isolation, COVID-19 testing, and surgery at a non-COVID-19 site have been developed to minimize risk of transmission. Despite this, it is likely that many patients will want to delay surgery for fear of contracting COVID-19. The aim of this study is to identify the number of patients who still want to proceed with planned elective orthopaedic surgery in this current environment.

Aims

Elective surgery has been severely curtailed as a result of the COVID-19 pandemic. There is little evidence to guide surgeons in assessing what processes should be put in place to restart elective surgery safely in a time of endemic COVID-19 in the community.

This population-based study investigated the incidence and trends in venous thromboembolic disease after total hip and knee arthroplasty over a ten-year period. Death or readmission for venous thromboembolic disease up to two years after surgery for all patients in Scotland was the primary outcome. The incidence of venous thromboembolic disease, including fatal pulmonary embolism, three months after surgery was 2.27% for primary hip arthroplasty and 1.79% for total knee arthroplasty. The incidence of fatal pulmonary embolism within three months was 0.22% for total hip arthroplasty and 0.15% for total knee arthroplasty. The majority of events occurred after hospital discharge, with no apparent trend over the period. The data support current advice that prophylaxis should be continued for at least six weeks following surgery. Despite the increased use of policies for prophylaxis and earlier mobilisation, there has been no change in the incidence of venous thromboembolic disease

Aims

The aim of this paper was to present the clinical features of patients with musculoskeletal sources of methicillin-sensitive Staphylococcus aureus (MSSA) septicaemia.

We randomly allocated 50 total knee replacements to scrub teams wearing body-exhaust suits (BES) or Rotecno occlusive clothing. The effectiveness of the clothing was assessed using air and wound bacterial counts. Bacteria were recovered from 62% of wounds (64% BES, 60% Rotecno). The mean air count was 0.5 CFU/ m. 3. with BES and 1.0 CFU/m. 3. with Rotecno (p = 0.014). The mean wound counts were 14 bacteria/wound with BES and eight bacteria/wound with Rotecno (p = 0.171). There was no correlation between the air and wound counts (r = −0.011, Spearman’s). The higher air counts suggest that Rotecno occlusive clothing is less effective than BES, but wounds were equally contaminated with both types of clothing suggesting that at very low levels of air contamination the contribution of bacteria to the wound from the air is irrelevant. Even doubling the air counts from 0.5 to 1.0 CFU/m. 3. had no detectable effect on the wound. This allows a reassessment to be made of other sources of contamination the effect of which would previously have been overwhelmed by contamination from air

Bactericidal levels of antibiotics are difficult to achieve in infected total joint arthroplasty when intravenous antibiotics or antibiotic-loaded cement spacers are used, but intra-articular (IA) delivery of antibiotics has been effective in several studies. This paper describes a protocol for IA delivery of antibiotics in infected knee arthroplasty, and summarises the results of a pharmacokinetic study and two clinical follow-up studies of especially difficult groups: methicillin-resistant Staphylococcus aureus and failed two-stage revision. In the pharmacokinetic study, the mean synovial vancomycin peak level was 9242 (3956 to 32 150; sd 7608 μg/mL) among the 11 patients studied. Serum trough level ranged from 4.2 to 25.2 μg/mL (mean, 12.3 μg/mL; average of 9.6% of the joint trough value), which exceeded minimal inhibitory concentration. The success rate exceeded 95% in the two clinical groups. IA delivery of antibiotics is shown to be safe and effective, and is now the first option for treatment of infected total joint arthroplasty in our institution.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):31–6.

We investigated the long-term changes in the Harris Hip and Knee Society scores (HSS and KSS) to determine whether they result from overall functional decline rather than actual changes in the condition of the prosthesis. The HHS for 106 total hip arthroplasties with a minimum follow-up of ten years, no medical complications after operation and no evidence of radiological loosening, and the KSS for 264 total knee arthroplasties with a minimum follow-up of 12 years and no medical complications after operation or signs of radiographical loosening were evaluated. There were statistically significant drops in the functional scoring components of the joint evaluation systems despite no loosening of the prostheses or other significant medical complications. The HHS declined at an average of 0.67 points per year from between three and ten years after operation (p < 0.0001). Contributing to this were deterioration in gait and limp (p < 0.0004), the use of support aids (p < 0.0001), the distance walked (p < 0.0001) and the ability to climb stairs (p < 0.0455). The functional component of the KSS declined significantly at an average 0.88 points per year betwen the third and 12th years (p < 0.0001). There were significant declines in every component of the functional score including the distance walked (p < 0.0001), the ability to climb stairs (p < 0.0001) and the use of support aids (p < 0.0001). The knee score component of the KSS did not decline significantly (p < 0.9750). The combination of functional and pain scores within the HHS system leads to an inaccurate decline in the entire score. The decline of HHS and Knee Society functional scores in total joint arthroplasties, in the absence of implant-related problems, suggests that deterioration in the functional capacity of ageing patients is an important factor in longitudinal studies using these scoring systems

Aims

Computer hexapod assisted orthopaedic surgery (CHAOS), is a method to achieve the intra-operative correction of long bone deformities using a hexapod external fixator before definitive internal fixation with minimally invasive stabilisation techniques.

The aims of this study were to determine the reliability of this method in a consecutive case series of patients undergoing femoral deformity correction, with a minimum six-month follow-up, to assess the complications and to define the ideal group of patients for whom this treatment is appropriate.

The use of robots in orthopaedic surgery is an emerging field that is gaining momentum. It has the potential for significant improvements in surgical planning, accuracy of component implantation and patient safety. Advocates of robot-assisted systems describe better patient outcomes through improved pre-operative planning and enhanced execution of surgery. However, costs, limited availability, a lack of evidence regarding the efficiency and safety of such systems and an absence of long-term high-impact studies have restricted the widespread implementation of these systems. We have reviewed the literature on the efficacy, safety and current understanding of the use of robotics in orthopaedics.

Cite this article: Bone Joint J 2015; 97-B:292–9.

Fresh-frozen allograft bone is frequently used in orthopaedic surgery. We investigated the incidence of allograft-related infection and analysed the outcomes of recipients of bacterial culture-positive allografts from our single-institute bone bank during bone transplantation. The fresh-frozen allografts were harvested in a strict sterile environment during total joint arthroplasty surgery and immediately stored in a freezer at -78º to -68º C after packing. Between January 2007 and December 2012, 2024 patients received 2083 allografts with a minimum of 12 months of follow-up. The overall allograft-associated infection rate was 1.2% (24/2024). Swab cultures of 2083 allografts taken before implantation revealed 21 (1.0%) positive findings. The 21 recipients were given various antibiotics at the individual orthopaedic surgeon’s discretion. At the latest follow-up, none of these 21 recipients displayed clinical signs of infection following treatment. Based on these findings, we conclude that an incidental positive culture finding for allografts does not correlate with subsequent surgical site infection. Additional prolonged post-operative antibiotic therapy may not be necessary for recipients of fresh-frozen bone allograft with positive culture findings.

Cite this article: Bone Joint J 2015;97-B:427–31.

Periprosthetic joint infection (PJI) complicates between 0.5% and 1.2% primary total hip arthroplasties (THAs) and may have devastating consequences. The traditional assessment of patients suffering from PJI has involved the serological study of inflammatory markers and microbiological analysis of samples obtained from the joint space. Treatment has involved debridement and revision arthroplasty performed in either one or two stages.

We present an update on the burden of PJI, strategies for its diagnosis and treatment, the challenge of resistant organisms and the need for definitive evidence to guide the treatment of PJI after THA.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):27–30.

Drug therapy forms an integral part of the management of many orthopaedic conditions. However, many medicines can produce serious adverse reactions if prescribed inappropriately, either alone or in combination with other drugs. Often these hazards are not appreciated. In response to this, the European Union recently issued legislation regarding safety measures which member states must adopt to minimise the risk of errors of medication.

In March 2014 the Medicines and Healthcare products Regulatory Agency and NHS England released a Patient Safety Alert initiative focussed on errors of medication. There have been similar initiatives in the United States under the auspices of The National Coordinating Council for Medication Error and The Joint Commission on the Accreditation of Healthcare Organizations. These initiatives have highlighted the importance of informing and educating clinicians.

Here, we discuss common drug interactions and contra-indications in orthopaedic practice. This is germane to safe and effective clinical care.

Cite this article: Bone Joint J 2015;97-B:434–41.

There has been an in increase in the availability of effective biological agents for the treatment of rheumatoid arthritis as well as a shift towards early diagnosis and management of the inflammatory process. This article explores the impact this may have on the place of orthopaedic surgery in the management of patients with rheumatoid arthritis.

Cite this article: Bone Joint J 2014;96-B:1287–9

We performed a systematic review and meta-analysis to compare the efficacy of intermittent mechanical compression combined with pharmacological thromboprophylaxis, against either mechanical compression or pharmacological prophylaxis in preventing deep-vein thrombosis (DVT) and pulmonary embolism in patients undergoing hip or knee replacement. A total of six randomised controlled trials, evaluating a total of 1399 patients, were identified. In knee arthroplasty, the rate of DVT was reduced from 18.7% with anticoagulation alone to 3.7% with combined modalities (risk ratio (RR) 0.27, p = 0.03; number needed to treat: seven). There was moderate, albeit non-significant, heterogeneity (I² = 42%). In hip replacement, there was a non-significant reduction in DVT from 8.7% with mechanical compression alone to 7.2% with additional pharmacological prophylaxis (RR 0.84) and a significant reduction in DVT from 9.7% with anticoagulation alone to 0.9% with additional mechanical compression (RR 0.17, p < 0.001; number needed to treat: 12), with no heterogeneity (I² = 0%). The included studies had insufficient power to demonstrate an effect on pulmonary embolism.

We conclude that the addition of intermittent mechanical leg compression augments the efficacy of anticoagulation in preventing DVT in patients undergoing both knee and hip replacement. Further research on the role of combined modalities in thromboprophylaxis in joint replacement and in other high-risk situations, such as fracture of the hip, is warranted.

Non-tuberculous mycobacterial (NTM) infection of the musculoskeletal tissue is a rare disease. An early and accurate diagnosis is often difficult because of the indolent clinical course and difficulty of isolating pathogens. Our goal was to determine the clinical features of musculoskeletal NTM infection and to present the treatment outcomes. A total of 29 patients (nine females, 20 males between 34 and 85 years old, mean age 61.7 years; 34 to 85) with NTM infection of the musculoskeletal system between 1998 to 2011 were identified and their treatment retrospectively analysed. Microbiological studies demonstrated NTM in 29 patients: the isolates were Mycobacterium intracellulare in six patients, M. fortuitum in three, M. abscessus in two and M. marinum in one. In the remaining patients we failed to identify the species. The involved sites were the hand/wrist in nine patients the knee in five patients, spine in four patients, foot in two patients, elbow in two patients, shoulder in one, ankle in two patients, leg in three patients and multiple in one patient. The mean interval between the appearance of symptoms and diagnosis was 20.8 months (1.5 to 180). All patients underwent surgical treatment and antimicrobial medication according to our protocol for chronic musculoskeletal infection: 20 patients had NTM-specific medication and nine had conventional antimicrobial therapy. At the final follow-up 22 patients were cured, three failed to respond to treatment and four were lost to follow-up. Identifying these diseases due the initial non-specific presentation can be difficult. Treatment consists of surgical intervention and adequate antimicrobial therapy, which can result in satisfactory outcomes.

Cite this article: Bone Joint J 2014;96-B:1561–5.

The objective of this study was to determine the effectiveness of screening and successful treatment of methicillin-resistant Staphylococcus aureus (MRSA) colonisation in elective orthopaedic patients on the subsequent risk of developing a surgical site infection (SSI) with MRSA.

We screened 5933 elective orthopaedic in-patients for MRSA at pre-operative assessment. Of these, 108 (1.8%) were colonised with MRSA and 90 subsequently underwent surgery. Despite effective eradication therapy, six of these (6.7%) had an SSI within one year of surgery. Among these infections, deep sepsis occurred in four cases (4.4%) and superficial infection in two (2.2%). The responsible organism in four of the six cases was MRSA. Further analysis showed that patients undergoing surgery for joint replacement of the lower limb were at significantly increased risk of an SSI if previously colonised with MRSA.

We conclude that previously MRSA-colonised patients undergoing elective surgery are at an increased risk of an SSI compared with other elective patients, and that this risk is significant for those undergoing joint replacement of the lower limb. Furthermore, when an infection occurs, it is likely to be due to MRSA.

Hyaline articular cartilage has been known to be a troublesome tissue to repair once damaged. Since the introduction of autologous chondrocyte implantation (ACI) in 1994, a renewed interest in the field of cartilage repair with new repair techniques and the hope for products that are regenerative have blossomed. This article reviews the basic science structure and function of articular cartilage, and techniques that are presently available to effect repair and their expected outcomes.

The Oxford hip and knee scores are used to measure the outcome after primary total hip and knee replacement. We propose a new layout for the instrument in which patients are always asked about both limbs. In addition, we have defined an alternative scoring method which accounts for missing data. Over a period of 4.5 years, 4086 (1423 patients) and 5708 (1458 patients) questionnaires were completed for hips and knees, respectively. The hip score had a pre-operative median of 70.8 (interquartile range (IQR) 58.3 to 81.2) decreasing to 20.8 (IQR 10.4 to 35.4) after one year. The knee score had a pre-operative median of 68.8 (IQR 56.2 to 79.2) decreasing to 29.2 (IQR 14.6 to 45.8). There was no further significant change in either score after one year. As a result of the data analysis, we suggest that the score percentiles can be used as a standard for auditing patients before and after operation.

The Control of Infection Committee at a specialist orthopaedic hospital prospectively collected data on all episodes of bacteriologically-proven deep infection arising after primary hip and knee replacements over a 15-year period from 1987 to 2001.

There were 10 735 patients who underwent primary hip or knee replacement. In 34 of 5947 hip replacements (0.57%) and 41 of 4788 knee replacements (0.86%) a deep infection developed. The most common infecting micro-organism was coagulase-negative staphylococcus, followed by Staphylococcus aureus, enterococci and streptococci. Of the infecting organisms, 72% were sensitive to routine prophylactic antimicrobial agents.

Of the infections, 29% (22) arose in the first three months following surgery, 35% between three months and one year (26), and 36% (27) after one year. Most cases were detected early and treated aggressively, with eradication of the infection in 96% (72). There was no significant change in the infection rate or type of infecting micro-organism over the course of this study.

These results set a benchmark, and importantly emphasise that only 64% of peri-prosthetic infections arise within one year of surgery. These results also illustrate the advantages of conducting joint replacement surgery in the isolation of a specialist hospital.

This study was undertaken to evaluate the safety and efficacy of retrievable inferior vena cava filters in high-risk orthopaedic patients. A total of 58 patients had a retrievable inferior vena cava filter placed as an adjunct to chemical and mechanical prophylaxis, most commonly for a history of previous deep-vein thrombosis or pulmonary embolism, polytrauma, or expected prolonged immobilisation. In total 56 patients (96.6%) had an uncomplicated post-operative course. Two patients (3.4%) died in the peri-operative period for unrelated reasons.

Of the 56 surviving patients, 50 (89%) were available for follow-up. A total of 32 filters (64%) were removed without complication at a mean of 37.8 days (4 to 238) after placement. There were four filters (8%) which were retained because of thrombosis at the filter site, and four (8%) were retained because of incorporation of the filter into the wall of the inferior vena cava. In ten cases (20%) the retrievable filter was left in place to continue as primary prophylaxis. No patient had post-removal thromboembolic complications.

A retrievable inferior vena cava filter, as an adjunct to chemical and mechanical prophylaxis, was a safe and effective means of reducing the acute risk of pulmonary embolism in this high-risk group of patients. Although most filters were removed without complications, thereby avoiding the long-term complications that have plagued permanent indwelling filters, a relatively high percentage of filters had to be left in situ.

We examined the usefulness of neutrophil CD64 expression in detecting local musculoskeletal infection and the impact of antibiotics on its expression. Of 141 patients suspected of musculoskeletal infection, 46 were confirmed by microbiological culture to be infected and 95 had infection excluded. The median CD64 count of patients with localised infection was 2230 molecules per cell (interquartile range (IQR) 918 to 4592) and that of the patients without infection was 937 molecules per cell (IQR 648 to 1309) (p < 0.001). The level of CD64 correlated with the CRP level in patients with infection, but not in those without infection (r = 0.59, p < 0.01). Receiver operator characteristic curve analysis revealed that CD64 was a good predictor of local infection. When the patients were subdivided into two groups based on the administration of antibiotics at the time of CD64 sampling, the sensitivity for detecting infection was better in those who had not received antibiotics.

These results suggest that measurement of CD64 expression is a useful marker for local musculoskeletal infection.

Using a computer-based quality assurance program, we analysed peri-operative data on 160 patients undergoing one-stage bilateral hip or knee arthroplasties under regional anaesthesia with routine anaesthetic monitoring and only using peripheral intravenous access for peri-operative safety. We monitored defined intra-operative adverse events such as hypotension, myocardial ischaemia, arrhythmias, hypovolaemia, hypertension and early post-operative complications. We also determined post-operative hip and knee function, and patient satisfaction with different aspects of the anaesthetic management. Those patients undergoing one-stage bilateral arthroplasties were matched according to a cross-stratification which used three variables (American Society of Anesthesiologists’ physical status scoring system, age and joint replaced) to patients undergoing unilateral hip or knee arthroplasties. Serious intra-operative adverse events were, with the exception of intra-operative hypotension, very infrequent in patients undergoing bilateral (nine adverse events) as well as unilateral arthroplasties (five adverse events). Early post-operative complications were also infrequent in both groups. However, the risks of receiving a heterologous blood transfusion (odds ratio 2.5; 95% confidence interval (CI) 1.3 to 5.0, estimated by exact conditional logistic regression) or vasoactive drugs (odds ratio 3.9; 95% CI 2.0 to 7.8) were significantly greater for patients undergoing bilateral operations. Patient satisfaction with anaesthesia was high; all patients who underwent the one-stage bilateral operation would choose the same anaesthetic technique again.