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.

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).

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 (I. 2. = 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 (I. 2. = 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

Post-discharge surveillance of surgical site infection is necessary if accurate rates of infection following surgery are to be available. We undertook a prospective study of 376 knee and hip replacements in 366 patients in order to estimate the rate of orthopaedic surgical site infection in the community. The inpatient infection was 3.1% and the post-discharge infection rate was 2.1%. We concluded that the use of telephone interviews of patients to identify the group at highest risk of having a surgical site infection (those who think they have an infection) with rapid follow-up by a professional trained to diagnose infection according to agreed criteria is an effective method of identifying infection after discharge from hospital

We describe a case of pyoderma gangrenosum which presented with severe wound breakdown after elective hip replacement. The patient was treated successfully with minimal wound debridement and steroids. This diagnosis should always be considered when confronted with an enlarging painful skin lesion which does not grow organisms when cultured and fails to respond to antibiotic therapy, especially if there are similar lesions in other sites. In patients who have a past history of pyoderma gangrenosum, prophylactic steroids may be indicated at the time of surgery or may be required early in the postoperative period

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

All surgical operations have the potential for contamination, and the equipment used can harbour bacteria. We collected samples from 100 elective primary hip and knee arthroplasties. These showed rates of contamination of 11.4% for the sucker tips, 14.5% for light handles, 9.4% for skin blades and 3.2% for the inside blades used during surgery; 28.7% of gloves used for preparation were also contaminated. Of the samples taken from the collection bags used during hip arthroplasty, 20% grew bacteria, which represents a significant microbial reservoir. Also, 17% of theatre gowns were contaminated at the end of the operation. Contamination was found in 10% of the needles used during closure of the fascia. Overall, 76% of the organisms grown were coagulase-negative staphylococcus. A total of 63% of operations showed contamination in the field of operation. Some changes in practice are suggested. Follow-up for a minimum of two years revealed one deep infection but the organism was not identified as a contaminant. These data provide a baseline for studying the bacteriology of the surgery of revision arthroplasty

We prospectively audited 79 patients undergoing primary knee or hip arthroplasty (38 knees, 41 hips) and found that 66% (58% of knees, 73% of hips) had at least one unit of blood transfused postoperatively, with a mean transfusion requirement of 1.3 units per patient (1.1 for knees, 0 to 6; 1.5 for hips, 0 to 4). We then established a new protocol for postoperative blood transfusion. This requires the calculation of the maximum allowable blood loss (MABL) that each individual patient can safely lose based upon their weight and preoperative haematocrit. The total blood loss up to this volume is replaced with colloid. When a patient’s total blood loss reaches their MABL their haematocrit is measured at the bedside using the Microspin system (Bayer plc, Newbury, UK). If their haematocrit is low (< 0.30 for men, < 0.27 for women), blood is transfused. As a safety net all patients have their haemoglobin formally checked on days 1, 2, and 3 after surgery and have a transfusion if the haemoglobin levels are less than 8.5 g/dl. We conducted a further audit of 82 patients (35 knees, 47 hips) after the introduction of this protocol. Under the new protocol only 24% of patients required blood (11% of knees, 34% of hips) with a mean transfusion requirement of 0.56 units per patient (0.26 for knees, 0 to 4; 0.79 for hips, 0 to 4). The use of clinical audit and the introduction of strict guidelines for transfusion can change transfusion practice and result in improved patient care. Our transfusion protocol is a simple and effective method of keeping transfusion to a minimum and is particularly useful in departments which do not have the facility to use autologous blood or reinfusion drains for elective orthopaedic surgery

Plots are an elegant and effective way to represent data. At their best they encourage the reader and promote comprehension. A graphical representation can give a far more intuitive feel to the pattern of results in the study than a list of numerical data, or the result of a statistical calculation.

The temptation to exaggerate differences or relationships between variables by using broken axes, overlaid axes, or inconsistent scaling between plots should be avoided.

A plot should be self-explanatory and not complicated. It should make good use of the available space. The axes should be scaled appropriately and labelled with an appropriate dimension.

Plots are recognised statistical methods of presenting data and usually require specialised statistical software to create them. The statistical analysis and methods to generate the plots are as important as the methodology of the study itself. The software, including dates and version numbers, as well as statistical tests should be appropriately referenced.

Following some of the guidance provided in this article will enhance a manuscript.

Cite this article: Bone Joint J 2015;97-B:1593–1603.

Currently, there is no animal model in which to evaluate the underlying physiological processes leading to the heterotopic ossification (HO) which forms in most combat-related and blast wounds. We sought to reproduce the ossification that forms under these circumstances in a rat by emulating patterns of injury seen in patients with severe injuries resulting from blasts. We investigated whether exposure to blast overpressure increased the prevalence of HO after transfemoral amputation performed within the zone of injury. We exposed rats to a blast overpressure alone (BOP-CTL), crush injury and femoral fracture followed by amputation through the zone of injury (AMP-CTL) or a combination of these (BOP-AMP). The presence of HO was evaluated using radiographs, micro-CT and histology. HO developed in none of nine BOP-CTL, six of nine AMP-CTL, and in all 20 BOP-AMP rats. Exposure to blast overpressure increased the prevalence of HO.

This model may thus be used to elucidate cellular and molecular pathways of HO, the effect of varying intensities of blast overpressure, and to evaluate new means of prophylaxis and treatment of heterotopic ossification.

Cite this article: Bone Joint J 2015;97-B:572–6

The purpose of this article is to provide the reader with a seven-step checklist that could help in minimising the risk of PJI. The check list includes strategies that can be implemented pre-operatively such as medical optimisation, and reduction of the bioburden by effective skin preparation or actions taking during surgery such as administration of timely and appropriate antibiotics or blood conservation, and finally implementation of post-operative protocols such as efforts to minimise wound drainage and haematoma formation.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):18–22.

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.

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.

Nanotechnology is the study, production and controlled manipulation of materials with a grain size < 100 nm. At this level, the laws of classical mechanics fall away and those of quantum mechanics take over, resulting in unique behaviour of matter in terms of melting point, conductivity and reactivity. Additionally, and likely more significant, as grain size decreases, the ratio of surface area to volume drastically increases, allowing for greater interaction between implants and the surrounding cellular environment. This favourable increase in surface area plays an important role in mesenchymal cell differentiation and ultimately bone–implant interactions.

Basic science and translational research have revealed important potential applications for nanotechnology in orthopaedic surgery, particularly with regard to improving the interaction between implants and host bone. Nanophase materials more closely match the architecture of native trabecular bone, thereby greatly improving the osseo-integration of orthopaedic implants. Nanophase-coated prostheses can also reduce bacterial adhesion more than conventionally surfaced prostheses. Nanophase selenium has shown great promise when used for tumour reconstructions, as has nanophase silver in the management of traumatic wounds. Nanophase silver may significantly improve healing of peripheral nerve injuries, and nanophase gold has powerful anti-inflammatory effects on tendon inflammation.

Considerable advances must be made in our understanding of the potential health risks of production, implantation and wear patterns of nanophase devices before they are approved for clinical use. Their potential, however, is considerable, and is likely to benefit us all in the future.

Cite this article: Bone Joint J 2014; 96-B: 569–73.

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.

Staphylococcus aureus is one of the leading causes of surgical site infection (SSI). Over the past decade there has been an increase in methicillin-resistant S. aureus (MRSA). This is a subpopulation of the bacterium with unique resistance and virulence characteristics. Nasal colonisation with either S. aureus or MRSA has been demonstrated to be an important independent risk factor associated with the increasing incidence and severity of SSI after orthopaedic surgery. Furthermore, there is an economic burden related to SSI following orthopaedic surgery, with MRSA-associated SSI leading to longer hospital stays and increased hospital costs. Although there is some controversy about the effectiveness of screening and eradication programmes, the literature suggests that patients should be screened and MRSA-positive patients treated before surgical admission in order to reduce the risk of SSI.

Cite this article: Bone Joint J 2013;95-B:4–9.

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.

Periosteum is important for bone homoeostasis through the release of bone morphogenetic proteins (BMPs) and their effect on osteoprogenitor cells. Smoking has an adverse effect on fracture healing and bone regeneration. The aim of this study was to evaluate the effect of smoking on the expression of the BMPs of human periosteum. Real-time polymerase chain reaction was performed for BMP-2,-4,-6,-7 gene expression in periosteal samples obtained from 45 fractured bones (19 smokers, 26 non-smokers) and 60 non-fractured bones (21 smokers, 39 non-smokers). A hierarchical model of BMP gene expression (BMP-2 > BMP-6 > BMP-4 > BMP-7) was demonstrated in all samples. When smokers and non-smokers were compared, a remarkable reduction in the gene expression of BMP-2, -4 and -6 was noticed in smokers. The comparison of fracture and non-fracture groups demonstrated a higher gene expression of BMP-2, -4 and -7 in the non-fracture samples. Within the subgroups (fracture and non-fracture), BMP gene expression in smokers was either lower but without statistical significance in the majority of BMPs, or similar to that in non-smokers with regard to BMP-4 in fracture and BMP-7 in non-fracture samples. In smokers, BMP gene expression of human periosteum was reduced, demonstrating the effect of smoking at the molecular level by reduction of mRNA transcription of periosteal BMPs. Among the BMPs studied, BMP-2 gene expression was significantly higher, highlighting its role in bone homoeostasis.

In order to assess current opinions on the long-term outcome after primary total hip replacement, we performed a multicentre, cross-sectional survey in 22 centres from 12 European countries. Different patient characteristics were categorised into ‘decreases chances’, ‘does not affect chances’, and ‘increases chances’ of a favourable long-term outcome, by 304 orthopaedic surgeons and 314 referring practitioners. The latter were less likely to associate age older than 80 years and obesity with a favourable outcome than orthopaedic surgeons (p < 0.001 and p = 0.006, respectively) and more likely to associate age younger than 50 years with a favourable outcome (p = 0.006). Comorbidity, rheumatoid arthritis, and poor bone quality were thought to be associated with a decreased chance of a favourable outcome. We found important differences in the opinions regarding long-term outcome after total hip replacement within and between referring practitioners and orthopaedic surgeons. These are likely to affect access to and the provision of total hip replacement.

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.