The microbiology of the infected knee arthroplasty.

We describe the results of a retrospective analysis of patients with microbiologically proven infection, who underwent revision TKA between 1994 and 2008. Of the 121 patients included in the study, 61 (50%) were male and 60 (50%) were female. The mean age was 71 (range 42-88) years. The most common organisms identified were Coagulase negative Staphylococcus (CNS) (49%) and Staphylococcus aureus (SA) (13%). The prevalence of CNS appears to be increasing, while that of SA and other organisms is decreasing. Vancomycin and teicoplanin were the most effective antibiotics with overall sensitivity rates of 100% and 96%, respectively. The results of our theoretical model suggest that gentamicin combined with vancomycin is the most effective empirical regimen. Staphylococcal species are the most common organisms encountered in deep infection of the knee. Gentamicin combined with vancomycin offers the most comprehensive protection and potentially allows for infected knee arthoplasties to be treated with a one-stage procedure.

The prophylaxis and treatment of heterotopic ossification following lower limb arthroplasty.

Heterotopic ossification following joint replacement in the lower limb occurs in 3% to 90% of cases. Higher grades of heterotopic ossification can result in significant limitation of function and can negate the benefits of joint replacement. The understanding of the pathophysiology of this condition has improved in recent years. It would appear to be related to a combination of systemic and local factors, including over-expression of bone morphogenetic protein-4. There is currently little evidence to support the routine use of prophylaxis for heterotopic ossification in arthroplasty patients, but prophylaxis is recommended by some for high-risk patients. Radiotherapy given as one dose of 7 Gy to 8 Gy, either pre-operatively (< four hours before) or post-operatively (within 72 hours of surgery), appears to be more effective than indometacin therapy (75 mg daily for six weeks). In cases of prophylaxis against recurrent heterotopic ossification following excision, recent work has suggested that a combination of radiotherapy and indometacin is effective. Advances in our understanding of this condition may permit the development of newer, safer treatment modalities.

Primary total knee replacement: a comparison of a nationally agreed guide to best practice and current surgical technique as determined by the North West Regional Arthroplasty Register.

INTRODUCTION: In 1999, a statement of best practice in primary total hip replacement was approved by the Council of the British Orthopaedic Association (BOA) and by the British Association for Surgery of the Knee (BASK) to provide a basis for regional and national auditable standards: we have compared practice in the North West of England to this document to ascertain adherence to this guide to best practice. MATERIALS AND METHODS: A direct comparison of data held on the North West Hip Arthroplasty Register for 2001/2002 and BASK/BOA guidelines was performed. 86 surgeons from 26 hospitals were included in the study. RESULTS: A mean of 93.3% of operations were performed in the surgeon's usual theatre. All of these theatres had vertical laminar air flow systems. 42.2% of respondents routinely used exhaust suits and 68.1% of respondents routinely used impermeable disposable gowns. All surgeons use some form of anti-thromboembolic prophylaxis; 66.2% use a combination of both mechanical and chemical means. All surgeons used antibiotic prophylaxis. The most popular choice of antibiotic was a cephalosporin. 93.7% of surgeons routinely use antibiotic-loaded cement. The PFC and Kinemax prostheses were the most commonly used prostheses. Interestingly, 97.7% of all first-choice implants were cemented. Only 2 surgeons used uncemented total knee replacement. 69.8% of surgeons used a posterior cruciate retaining design. A midline longitudinal skin incision is used by 87.2% of surgeons, a medial longitudinal skin incision by 7.0% and a lateral longitudinal skin incision by 5.8% of surgeons. A medial parapatellar capsular incision is preferred by 91.9% with the remainder using mid vastus or trivector retaining capsulotomy. Closure of capsulotomies is performed in flexion by 65.1% and in extension by 34.9%. In patients with osteoarthritis, 38.4% routinely resurfaced the patella, 34.9% never resurfaced the patella and 26.7% selectively resurfaced. This was in direct contrast to practice for patients with rheumatoid arthritis in whom 66.3% routinely resurfaced the patella, 22.1% never resurfaced the patella and 11.6% selectively resurfaced. DISCUSSION AND CONCLUSIONS: This study has demonstrated variation of practice in hip arthroplasty across the North West region and significant divergence from the BASK/BOA statement of best practice. The introduction of a properly funded national arthroplasty register will surely help to clarify the effect of such diverse practice on patient outcome.

Intraoperative bacterial contamination in operations for joint replacement.

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.

Primary total hip replacement: a comparison of a nationally agreed guide to best practice and current surgical technique as determined by the North West Regional Arthroplasty Register.

BACKGROUND: In 1999, a statement of best practice in primary total hip replacement was approved by the Council of the British Orthopaedic Association (BOA) and by the British Hip Society (BHS) to provide a basis for regional and national auditable standards. We have compared practice in the North West Region of England to this document to ascertain adherence to this guide to best practice. METHODS: A total of 86 surgeons from 26 hospitals were included in a questionnaire study. RESULTS: A mean of 93.3% of operations were performed in the surgeon's usual theatre. All of these theatres had vertical laminar air flow systems. Of respondents, 42.2% routinely used exhaust suits, 68.1% routinely used impermeable disposable gowns, and 26.1% used impermeable re-usable gowns. The Charnley femoral and acetabular prostheses were the most commonly used prostheses. All surgeons used some form of anti-thromboembolic prophylaxis: 66.2% use a combination of both mechanical and chemical means. All surgeons used antibiotic prophylaxis. The most popular choice of antibiotic was a cephalosporin--70.7% used a 3-dose regimen over 24 h, 2.6% of surgeons continued antibiotic prophylaxis for 48 h after surgery, and 93.7% of surgeons routinely use antibiotic-loaded cement. All surgeons routinely cleaned, irrigated and dried the acetabulum and femur before cement insertion. Only one surgeon did not use any form of femoral canal occlusion. 69.4% used an intramedullary bone block. Retrograde filling of the femoral shaft by means of a cement gun was practised by 65.1%. CONCLUSIONS: This study has demonstrated considerable variation of practice in total hip arthroplasty across the North West Region and significant divergence from the statement of best practice approved by the BOA and BHS. The introduction of a properly funded national hip register will surely help to clarify the effect of such diverse practice on patient outcome. We would recommend that all trusts locally audit their practices and correlate them with these nationally agreed guidelines.

Two stage revision knee arthroplasty for infection with massive bone loss. A technique to achieve spacer stability.

We report a technique for the intra-operative production of an antibiotic-impregnated cement spacer, reinforced with an intramedullary nail. The spacer is designed for use in cases where significant bone loss and/or ligamentous instability prevent the formation of a stable joint when using a conventional spacer during a two-stage revision knee arthroplasty. This technique has been performed in eleven patients. Nine patients have subsequently undergone a second-stage procedure. Two patients died of unrelated causes before a second-stage could be performed. In all but one case, the infection has been successfully eradicated and patients remain infection free at a mean follow-up of 32 months (range 21-64 months). We believe that the described technique is an effective alternative to the traditional spacer, in patients with significant bone loss and/or ligamentous instability. It delivers antibiotics locally, while producing a mechanically stable joint, on which the patient can mobilise, maintaining leg length and tissue tensions.

The microbiology of infected hip arthroplasty.

Infection following joint replacement surgery although rare presents a challenging problem. Bacterial resistance to antibiotics is an emerging problem. We analysed the microbiology of 337 single-stage revisions for deep infection. Coagulase negative staphylococcus was found to be the predominant organism, although staphylococcus aureus is gaining importance. Gentamicin only provides cover for 64.1% of organisms. Resistance to this commonly used antibiotic prophylaxis is escalating. Fusidic acid and erythromycin provide improved cover. We would suggest on a microbiological basis that these antibiotics be considered for addition to acrylic bone cement. This will provide local antibiotic delivery when performing a revision for deep infection.

Comfort assessment of personal protection systems during total joint arthroplasty using a novel multi-dimensional evaluation tool.

INTRODUCTION: A number of studies have assessed the usefulness of surgical gowns and exhaust suits with regards to barrier function and protection afforded to healthcare workers from blood strike-through, splashes and aerosols. PATIENTS AND METHODS: We have performed a comfort assessment comparison between the Charnley exhaust suit, disposable gown plus visor and the Stryker Steri-Shield system using a newly developed objective multidimensional ergonomic tool designed to measure wearable comfort across the dimensions of emotion, attachment, harm, perceived change, movement and anxiety. RESULTS: The total mean Comfort Rating Scale value for a disposable gown plus visor was 16.1 with a mean dimensional score of 2.7 (range, 0.2-8.4), for the Charnley system the values were 51.4 and 8.6 (range, 5.9-12.8), respectively, and for the Stryker Steri-Shield 15.4 and 2.6 (range, 0.8-5.6). CONCLUSIONS: The Steri-Shield system provides the least variation in comfort and, as such, may offer the best combination of comfort, protective qualities and form or style of personal protection equipment for lower limb arthroplasty operations.

Safety and efficacy of intra-articular injection of the hip.

The aim of the present study was twofold: a) to establish the therapeutic efficacy of the hip injection with marcaine and steroid; (b) to establish the safety of the procedure with respect to possible bacterial contamination at the time of passage of needle into the hip joint. Thirty-five patients with osteoarthritis of the hip were injected. All patients were admitted as day cases and the procedure was performed in a laminar flow theatre under full aseptic conditions. The hip was aspirated before injection. Aspirate and injecting needles were sent for microbiological examination. Both aerobic and anaerobic cultures were performed. All patients were followed up for three months after hip injection. Microbiology results were not revealed to reviewing clinicians. All patients were reviewed at two weeks and at twelve weeks. Thirty-three patients (94.3%) had no growth in the samples. Two cases out of thirty-five hips had a positive culture but none of the patients went on to develop clinical sepsis. Patient response for pain in the hip was graded using a 10 point visual analogue scale (VAS) with 10 point as maximum pain and 0 points as no pain. Pre-injection the patient VAS for pain was a mean value of 6.4 0.77 (median, 6). The mean value of VAS score at 2 weeks dropped to 2.6 2.7 with median of 2. This difference was highly significant (p=0.003). At 12 weeks mean VAS score was 2.7 2.5 with median value of 2 (p=001). Three patients were worse after the injection. We found the hip injection to be safe. The risk of bacterial contamination is low provided a strict aseptic protocol is observed. In this study, one third of the patients had excellent pain relief for 3 months after the injection but in two thirds of cases it failed to provide complete, long-term pain relief (> 3 months). (Hip International 2002; 4: 378-82).