Histopathology in Periprosthetic Joint Infection: When Will the Morphomolecular Diagnosis Be a Reality?

The presence of a polymorphonuclear neutrophil infiltrate in periprosthetic tissues has been shown to correlate closely with the diagnosis of septic implant failure. The histological criterion considered by the Musculoskeletal Infection Society to be diagnostic of periprosthetic joint infection is "greater than five neutrophils per high-power field in five high-power fields observed from histologic analysis of periprosthetic tissue at ×400 magnification." Surgeons and pathologists should be aware of the qualifications introduced by different authors during the last years in the histological techniques, samples for histological study, cutoffs used for the diagnosis of infection, and types of patients studied. Recently, immunohistochemistry and histochemistry studies have appeared which suggest that the cutoff point of five polymorphonuclear neutrophils in five high-power fields is too high for the diagnosis of many periprosthetic joint infections. Therefore, morphomolecular techniques could help in the future to achieve a more reliable histological diagnosis of periprosthetic joint infection.

Hip prostheses in young adults. Surface prostheses and short-stem prostheses. / Las prótesis de cadera en el adulto joven. Prótesis de superficie y prótesis de vástago corto.

The poor results obtained in young patients when using a conventional prosthesis led to the resurgence of hip resurfacing to find less invasive implants for the bone. Young patients present a demand for additional activity, which makes them a serious challenge for the survival of implants. In addition, new information technologies contribute decisively to the preference for non-cemented prostheses. Maintaining quality of life, preserving the bone and soft tissues, as well as achieving a very stable implant, are the goals of every hip orthopaedic surgeon for these patients. The results in research point to the use of smaller prostheses, which use the metaphyseal zone more and less the diaphyseal zone, and hence the large number of the abovementioned short stem prostheses. Both models are principally indicated in the young adult. Their revision should be a more simple operation, but this is only true for hip resurfacing, not for short stems.

[Clinical safety and professional liability claims in Orthopaedic Surgery and Traumatology]. / Seguridad clínica y reclamaciones por responsabilidad profesional en Cirugía Ortopédica y Traumatología.

The specialist in orthopaedic and traumatological surgery, like any other doctor, is subject to the current legal provisions while exercising their profession. Mandatory training in the medical-legal aspects of health care is essential. Claims against doctors are a reality, and orthopaedic and traumatological surgery holds first place in terms of frequency of claims according to the data from the General Council of Official Colleges of Doctors of Catalonia. Professionals must be aware of the fundamental aspects of medical professional liability, as well as specific aspects, such as defensive medicine and clinical safety. The understanding of these medical-legal aspects in the routine clinical practice can help to pave the way towards a satisfactory and safe professional career. The aim of this review is to contribute to this training, for the benefit of professionals and patients.

KLIC-score for predicting early failure in prosthetic joint infections treated with debridement, implant retention and antibiotics.

Debridement, irrigation and antibiotic treatment form the current approach in early prosthetic joint infection (PJI). Our aim was to design a score to predict patients with a higher risk of failure. From 1999 to 2014 early PJIs were prospectively collected and retrospectively reviewed. The primary end-point was early failure defined as: 1) the need for unscheduled surgery, 2) death-related infection within the first 60 days after debridement or 3) the need for suppressive antibiotic treatment. A score was built-up according to the logistic regression coefficients of variables available before debridement. A total of 222 patients met the inclusion criteria. The most frequently isolated microorganisms were coagulase-negative staphylococci (95 cases, 42.8%) and Staphylococcus aureus (81 cases, 36.5%). Treatment of 52 (23.4%) cases failed. Independent predictors of failure were: chronic renal failure (OR 5.92, 95% CI 1.47-23.85), liver cirrhosis (OR 4.46, 95% CI 1.15-17.24), revision surgery (OR 4.34, 95% CI 1.34-14.04) or femoral neck fracture (OR 4.39, 95% CI1.16-16.62) compared with primary arthroplasty, C reactive protein >11.5 mg/dL (OR 12.308, 95% CI 4.56-33.19), cemented prosthesis (OR 8.71, 95% CI 1.95-38.97) and when all intraoperative cultures were positive (OR 6.30, 95% CI 1.84-21.53). A score for predicting the risk of failure was designed using preoperative factors (KLIC-score: Kidney, Liver, Index surgery, Cemented prosthesis and C-reactive protein value) and it ranged between 0 and 9.5 points. Patients with scores of ≤2, >2-3.5, 4-5, >5-6.5 and ≥7 had failure rates of 4.5%, 19.4%, 55%, 71.4% and 100%, respectively. The KLIC-score was highly predictive of early failure after debridement. In the future, it would be necessary to validate our score using cohorts from other institutions.

[Screening with angiographic images prior to (99m)Tc-HMPAO labelled leukocyte scintigraphy in the diagnosis of periprosthetic infection]. / Cribado mediante angiogammagrafía previo a la realización de gammagrafía con leucocitos (99m)Tc-HMPAO en el diagnóstico de infección de prótesis articulares.

AIM: To evaluate the impact of the angioscintigrapy of the three phase bone scan as screening method to rule out infection of the hip and knee prosthesis prior to performing the (99m)Tc-HMPAO leukocyte scintigraphy. MATERIAL AND METHODS: A total of 120 (70 women, 50 men; mean age 71±11years) with clinical suspicion of hip (n=63) or knee (n=57) infection of the prosthesis and clinical suspicion of infection were evaluated prospectively. All patients underwent three-phase bone scan (angioscintigraphy, vascular and bone phase) and (99m)Tc-HMPAO-labelled white blood cell scintigraphy. Final diagnosis of infection was made by microbiological documentation or clinical follow-up for at least 12months. RESULTS: Eighteen out of 120 patients were diagnosed of infection of hip prosthesis (n=10) or knee prosthesis (n=8). The angioscintigraphy was positive in 15/18 infected cases and in 21/102 of the non-infected cases with a sensitivity of 83%, specificity of 79% and negative predictive value of 97%. Sensitivity and specificity of (99m)Tc-HMPAO leukocyte scintigraphy were 72% and 95%, respectively. If the leukocyte labeled scintigraphies had been used exclusively for patients with positive angioscintigraphy, this would have saved up to 70% of the (99m)Tc-HMPAO leukocyte scintigraphies performed. There were no cases of infection with positive labeled leukocyte scintigraphy and negative angioscintigraphy. CONCLUSION: Angioscintigraphy (blood flow phase of bone scan) is a useful technique for screening for hip and knee joint prosthesis infection, significantly reducing the need for (99m)Tc-HMPAO leukocyte scintigraphy without affecting the sensitivity of the technique.

[Analysis of the failures of a cemented constrained liner model in patients with a high dislocation risk]. / Análisis de los fracasos de un modelo de cotilo constreñido cementado en pacientes de alto riesgo de luxación.

OBJECTIVE: To evaluate the short-term results of an ultra high molecular weight polyethylene retentive cup in patients at high risk of dislocation, either primary or revision surgery. MATERIAL AND METHOD: Retrospective review of 38 cases in order to determine the rate of survival and failure analysis of a constrained cemented cup, with a mean follow-up of 27 months. We studied demographic data, complications, especially re-dislocations of the prosthesis and, also the likely causes of system failure analyzed. RESULTS: In 21.05% (8 cases) were primary surgery and 78.95% were revision surgery (30 cases). The overall survival rate by Kaplan-Meier method was 70.7 months. During follow-up 3 patients died due to causes unrelated to surgery and 2 infections occurred. 12 hips had at least two previous surgeries done. It wasn't any case of aseptic loosening. Four patients presented dislocation, all with a 22 mm head (P=.008). Our statistical analysis didn't found relationship between the abduction cup angle and implant failure (P=.22). CONCLUSIONS: The ultra high molecular weight polyethylene retentive cup evaluated in this series has provided satisfactory short-term results in hip arthroplasty patients at high risk of dislocation.

Comparison of bacterial results from conventional cultures of the periprosthetic membrane and the synovial or pseudocapsule during hip revision arthroplasty.

INTRODUCTION: Bacterial identification is essential to diagnose and treat a revision for prosthetic loosening of an infected hip. The purpose of this study was to determine whether conventional cultures from the periprosthetic membrane are superior to synovial/pseudocapsule samples in the diagnosis of infection in hip revision arthroplasty. MATERIALS AND METHODS: We performed a prospective study including all hip revisions from October 2009 to October of 2011. Once the implants were removed and prior to the administration of the antibiotic prophylaxis, six periprosthetic samples from different sites were sent to the laboratory for culturing: two periprosthetic fluid samples, two solid material (synovial/pseudocapsule) samples and two swabs. Once the six samples were taken, antibiotic prophylaxis was administered and just as the implant was removed, two more solid samples of the periprosthetic membrane were obtained. RESULTS: Of a total of 86 hip revision surgeries, 22 were considered septic revisions postoperatively, of which 16 resulted in positive cultures. Of these 16 revisions, 14 obtained the same microbiologic diagnostic when considering either the synovial/pseudocapsule culture results or the solid membrane sample. CONCLUSIONS: We conclude that the membrane sample for a conventional culture is not superior to the synovial/pseudocapsule sample in detecting microorganisms.

Total hip arthroplasty in HIV-infected patients: a retrospective, controlled study.

BACKGROUND: Although HIV-infected patients are at greater risk of presenting with ischaemic necrosis of the femoral head, there have been concerns about whether total hip arthroplasty (THA) may have worse outcomes than expected. METHODS: From the Orthopedic and Trauma Surgery database we identified all patients who had undergone THA because of ischaemic necrosis of the femoral head from January 2001 until March 2010. Patient's diagnosis of HIV infection was confirmed at the time of arthroplasty by cross-matching with the HIV unit database. For every THA in HIV-infected patients, two THAs in patients not known to be HIV-infected, with the same diagnosis of ischaemic necrosis of the femoral head and having undergone surgery over the same period, were randomly selected. THAs were compared in HIV- and non-HIV-infected patients for surgical procedure, in-patient stay and long-term prognosis. RESULTS: There were 18 THAs in 13 HIV-infected patients and 36 THAs in 27 non-HIV-infected patients. No significant differences were observed in the mean time spent in surgery (106 vs. 109 minutes, respectively; P = 0.66), the need for red cell transfusion (1 vs. 4, respectively; P = 0.48) or the mean duration of hospitalization (7.8 vs. 9.4 days, respectively; P = 0.48). The two groups showed similar postoperative functional results, which were maintained until the end of the follow-up period (median 3.3 years in the HIV-positive group and 5.8 years in the HIV-negative group). CONCLUSION: Our study suggests that the outcome of THA in HIV-positive patients is not worse than that of HIV-negative patients, although future research on larger numbers of patients is required to confirm this.

[Study of the consistency of a system for preoperative planning digital in total arthroplasty of the hip]. / Estudio de la concordancia de un sistema de planificación preoperatoria digital en artroplastia total de cadera.

OBJECTIVE: Check the agreement of a preoperative digital templating, compared with the final result in the postoperative radiograph. MATERIAL AND METHOD: The study was carried out on a 55 total hip prosthesis. A templating-software Neteous (Socincer, Gijón, Spain) was used. Agreement was measured using the Kappa Index for the stem offset or Lin Index for others variables: stem size, cup size, femoral neck length, and the distance from the center of rotation of the femoral head to the lesser trochanter. The percentage of accurate hits was also described. RESULTS: Stem size: The exact success or error of only one size was of 61.6%. Quantitatively the Lin Index was 0.64 (substantial). Horizontal offset: satisfactory agreement was obtained (Kappa index of 0.75). In 6 cases (10.90%) was changed to lateralized during surgery, for more joint stability. Size of the cup: the agreement obtained was 0.67 (substantial) with a hit grade of 43.6%. Prosthetic neck length: the exact hit or error of only one size were found in 50.9%, moderate level of agreement. Distance from the center of rotation to the lesser trochanter: was observed for almost perfect agreement with Lin Index of 0.95. The exact percentage of hits or gap error less than 5mm was 74.5%. DISCUSSION AND CONCLUSION: In ours hands, the preoperative templating software analyzed, has provided acceptable agreement rates, when compared with the postoperative result. But it takes more works verified by independent observers.

Usefulness of monitoring linezolid trough serum concentration in prolonged treatments.

Linezolid has proven valuable in musculoskeletal infections, however, failure and resistance have been described and toxicity is worrisome when more than 28 days are necessary. We describe the first 5 cases in whom linezolid trough serum concentrations were weekly measured and its relationship with clinical outcome and toxicity.

[Prosthetic joint infection by Candida spp.]. / Infección por Candida spp. sobre prótesis articulares.

INTRODUCTION: Fungal periprosthetic infectionis a rare entity. The aim of this report was to review our experience in two different educational hospitals. MATERIAL AND METHODS: patients with documented prosthetic joint infection due to Candida spp. from February 2002 to October 2010 were retrospectively reviewed. Demographics, microbiological data, treatment and outcome of each patient was recorded. RESULTS: Ten patients, 8 women and 2 men, with a meanage of 77.7 (range 66-92) years were identified. Nine patients had previous bacterial infection, received antibiotic treatment for more than 15 days and required multiple surgeries. The most frequent species was C. albicans with 6 cases. All patients received fluconazole and surgical treatment consisted of debridement without removing the implant in 3 cases and 2-stage exchange with a spacer in 7. The first surgical and antifungal approach failed in all cases and a second debridement was necessary in one case, a resection arthroplasty in 8 and chronic suppressive treatment with fluconazol in one. After a mean follow-up of 31 (range 2-67) months, two patients were free of infection. CONCLUSION: Prosthetic joint infection was associated with long-term antibiotic treatment and multiples previous surgeries. Treatment with fluconazol and debridement or two stage replacement with a spacer was associated with a high failure rate.

Comparison of a low-pressure and a high-pressure pulsatile lavage during débridement for orthopaedic implant infection.

INTRODUCTION: The aim of our study was to compare the effectiveness of high-pressure pulsatile lavage and low-pressure lavage in patients with an orthopaedic implant infection treated with open débridement followed by antibiotic treatment. PATIENTS AND METHODS: Patients with an orthopaedic implant infection requiring open débridement from January 2008 to August 2009 were randomized prospectively to a low-pressure or a high-pressure pulsatile lavage arm. Relevant information about demographics, co-morbidity, type of implant, microbiology data, surgical treatment, and outcome were recorded. Comparison of proportions was made using χ(2) test or Fisher exact test when necessary. The Kaplan-Meier survival method was used to estimate the cumulative probability of treatment failure from open débridement to the last visit. RESULTS: Seventy-nine patients were included. There were no differences between the main characteristics between both groups (p > 0.05). Mean (SD) age of the whole cohort was 70.2 (11.9) years. There were 46 infections on knee prosthesis, 17 on hip prosthesis, 7 on hip hemiarthroplasties and 9 on osteosynthesis devices. There were 69 acute post-surgical infections, 8 acute haematogenous infections and 2 chronic infections. The most common microorganisms isolated were coagulase-negative Staphylococci in 34 cases, Staphylococcus aureus in 26 and Escherichia coli in 19 cases. There were 30 polymicrobial infections. A total of 42 and 37 patients were randomized to a high-pressure pulsatile or a low-pressure lavage, respectively. There was no difference in the success rate between both arms (80.9 vs. 86.5%, p = 0.56). CONCLUSION: The use of a high-pressure pulsatile lavage during open débridement of implant infections had a similar success rate as a low-pressure lavage.

Outcome and predictors of treatment failure in early post-surgical prosthetic joint infections due to Staphylococcus aureus treated with debridement.

Experience with debridement and prosthesis retention in early prosthetic joint infections (PJI) due to Staphylococcus aureus is scarce. The present study aimed to evaluate the outcome and predictors of failure. Patients prospectively registered with an early PJI due to S. aureus and 2 years of follow-up were reviewed. Demographics, co-morbidity, type of implant, clinical manifestations, surgical treatment, antimicrobial therapy and outcome were recorded. Remission was defined when the patient had no symptoms of infection, the prosthesis was retained and C-reactive protein (CRP) was ≤ 1 mg/dL. Univariate and multivariate analysis were performed. Fifty-three patients with a mean ± SD age of 70 ± 10.8 years were reviewed. Thirty-five infections were on knee prosthesis and 18 were on hip prosthesis. The mean ± SD duration of intravenous and oral antibiotics was 10.6 ± 6.7 and 88 ± 45.9 days, respectively. After 2 years of follow-up, 40 (75.5%) patients were in remission. Variables independently associated with failure were the need for a second debridement (OR 20.4, 95% CI 2.3-166.6, p 0.006) and a CRP > 22 mg/dL (OR 9.8, 95% CI 1.5-62.5, p 0.01). The onset of the infection within the 25 days after joint arthroplasty was at the limit of significance (OR 8.3, 95% CI 0.8-85.6, p 0.07). Debridement followed by a short period of antibiotics is a reasonable treatment option in early PJI due to S. aureus. Predictors of failure were the need for a second debridement to control the infection a CRP > 22 mg/dL and the infection onset within the first 25 days after joint arthroplasty.

Hyaline cartilage surface study with an environmental scanning electron microscope. An experimental study.

To obtain images of the articular surface of fresh osteochondral grafts using an environmental scanning electron microscope (ESEM). To evaluate and compare the main morphological aspects of the chondral surface of the fresh grafts. To develop a validated classification system on the basis of the images obtained via the ESEM. The study was based on osteochondral fragments from the internal condyle of the knee joint of New Zealand rabbits, corresponding to fresh chondral surface. One hundred images were obtained via the ESEM and these were classified by two observers according to a category system. The Kappa index and the corresponding confidence interval (CI) were calculated. Of the samples analysed, 62-72% had an even surface. Among the samples with an uneven surface 17-22% had a hillocky appearance and 12-16% a knobbly appearance. As regards splits, these were not observed in 92-95% of the surfaces; 4-7% showed superficial splits and only 1% deep splits. In 78-82% of cases no lacunae in the surface were observed, while 17-20% showed filled lacunae and only 1-2% presented empty lacunae. The study demonstrates that the ESEM is useful for obtaining and classifying images of osteochondral grafts.

Results of treatment of subtrochanteric femoral fractures with the AO/ASIF Long Trochanteric Fixation Nail (LTFN).

PURPOSE OF THE STUDY: This retrospective study reports on the clinical results of a group of 23 patients with subtrochanteric femoral fractures using the Long Trochanteric Fixation Nail (LTFN). MATERIAL: Between January 2005 and January 2008, 23 patients (20 women, 3 men; average age: 64.8 years old) with subtrochanteric femoral fractures were treated surgically. According to the AO/ASIF Classification, the most frequent fracture type was an 32-A1. They were also classified regarding the Seinsheimer Classification, in which the commonest type was the IIB. Of the 23 fractures, 14 of them had been the result of an unexpected fall, 2 were the result of a high-energy trauma and 7 consisted of pathologic fractures. METHODS: All the patients were treated using the LTFN device and they all received clinical and radiological follow-ups at least until their fractures were consolidated. The average surgery time, average decrease in haemoglobin in the first 24 hours post- surgery, average need for red blood cell transfusion, postoperative mortality at a 6th month follow-up, time to autonomous deambulation, most frequent destination at the time of discharge, average time for consolidation of the fracture and average follow-up time were reported. Intraoperative and postoperative complications were also recorded. RESULTS: The average surgery time from cut to stitch was 97.45 minutes with the decrease in haemoglobin averaging 26.45 g/L and, on average, the need for red blood cell transfusion was 1.12 concentrates. In the first postoperative week, 57.1% of the total number patients were capable of deambulation. The time to hospital discharge was 12.9 days. After an average follow-up of 13.9 months, total weightbearing was achieved in the 64.7% of the patients. The average consolidation time was 21.6 weeks and none of the patients developed pseudoarthrosis. Technical failures were seen in 4.3% of the cases: 1 patient suffered a migration of the distal locking screw. There were no cases of deep infection, cut-out, bending/breaking of the implant, malrotation or fracture of the femoral shaft at the tip of the implant. DISCUSSION: From a mechanical point of view the use of a long intramedullary nail in combination with a blade or a screw seems to be the most appropriate treatment for subtrochanteric fractures of the femur. Despite the improvement of implants and surgical techniques, failures due to complications are still considerable. The low distal shaft diameter of the LTFN, in combination with an extremely precise positioning of the blade in the middle of the femoral head, can prevent mechanical complications. Open reduction and cerclage cabling may be required so as to obtain a correct alignment of the fracture. CONCLUSION: We conclude that the LTFN is a safe and reliable intramedullary device for the treatment of subtrochanteric fractures of the femur. Deambulation within the first postoperative surgery is possible when positioned properly. Its implantation requires more surgical time than the standard nails.

[Potential use of bone marrow scintigraphy in suspected prosthetic hip infection evaluated with 99mTc-HMPAO-leukocytes]. / Valor de la gammagrafía de médula macrofágica en el diagnóstico de infección de prótesis total de cadera estudiada con leucocitos Tc-HMPAO.

AIM: To evaluate the usefulness of (99m)Tc-Sulphur colloid when combined with leukocyte scintigraphy in suspected prosthetic hip infection, comparing the results with information from (99m)Tc-HMPAO-leukocyte scintigraphy alone. MATERIALS AND METHODS: Seventy patients (42 women, 28 men; mean age 68 +/- 13 years) with painful hip prostheses and suspicion of infection were evaluated prospectively. All patients had bone scintigraphy, (99m)Tc-HMPAO-labelled white blood cell scintigraphy and (99m)Tc-Sulphur colloid bone marrow scintigraphy. ESR and CRP levels were measured in all patients. The final diagnosis was made with microbiological findings or by clinical follow up of at least 12 months. RESULTS: Infections were diagnosed in 12 of the 70 patients (3 coagulase-negative Staphylococcus, 2 Staphylococcus aureus, 2 Staphylococcus epidermidis, 2 enterococcus and 3 polymicrobial agents). ESR and CRP values were higher in patients with infection than in patients without infection (51.8 +/- 29.4 vs. 25.4 +/- 16.4 and 2.8 +/- 2.2 vs. 1.1 +/- 1.3, respectively; p < 0.05). Bone scintigraphy did not show a characteristic pattern to differentiate infection from aseptic loosening. The pool phase of the bone scintigraphy was positive in only 3/12 patients with infection (25 %). Sensitivity and specificity of the leukocyte scintigraphy was 83 % and 57 %, respectively. When the results of the bone marrow scintigraphy were added, these values increased to 92 % and 98 %, respectively. CONCLUSION: Performing bone marrow scintigraphy significantly improves results when compared with leukocyte scintigraphy alone in the diagnosis of infected hip prostheses. Bone scintigraphy did not help to differentiate aseptic loosening from infection in this series.

Fracture of a ceramic liner in a total hip arthroplasty with a sandwich cup.

Alumina ceramic-on-ceramic total hip arthroplasty (THA) has been widely used due to its advantages such as low wear, scratch resistance, wettable surface and relatively low biological reactivity of the wear particles. Nevertheless, this material in THA still persists to be one of the major concerns about the risk of fracture, due to its brittleness. Many authors have reported a fracture of the ceramic head but few reported a fracture of the ceramic acetabular insert. In order to reduce the rigidity of the ceramic-on-ceramic coupling and prevent an impingement between the rim of the ceramic liner and the metal neck of the femoral stem, a modular acetabular component with a sandwich insertion (alumina/polyethylene/titanium) was proposed. We report the fracture of the ceramic acetabular liner of such a ceramic sandwich cup due to a slightly retroverted position of the cup that causes an impingement between the femoral stem and the rim of the insert. The fracture occurred 3 years after the operation without trauma. At revision the entire cup was replaced using a polyethylene liner without inner ceramic liner.

Treatment of acute post-surgical infection of joint arthroplasty.

The best antibiotic regimen for acute prosthetic joint infection, treated without removal of the implant, has not been well-defined. This study describes the use of a protocol based on oral rifampicin combinations to treat 47 cases that were followed prospectively for a 2-year period. The regimen used most commonly was levofloxacin 500 mg/24 h plus rifampicin 600 mg/24 h for a mean duration of 2.7 +/- 1 months. The cure rate was 76.9%, and the only independent risk-factor associated with treatment failure was infection caused by methicillin-resistant Staphylococcus aureus or Enterococcus spp. (OR 17.6, p 0.003). Overall, the results suggested that use of oral antibiotics, including rifampicin, for 2-3 months was a good treatment option.

Usefulness of teicoplanin for preventing methicillin-resistant Staphylococcus aureus infections in orthopedic surgery.

In order to gather more data on the use of teicoplanin for reducing MRSA infections in high-risk populations, the present study was conducted. At a hospital in Barcelona, Spain, there was a high prevalence of MRSA infections among patients who underwent surgery for femoral neck fracture during the first 5 months of 2002 (period A) when cefuroxime was the antibiotic prophylaxis. During the following 12 months (period B) 600 mg of teicoplanin was added to cefuroxime. The rates of overall and MRSA infection during period A were 5.07 and 2.73%, respectively. Pulsed-field gel electrophoresis demonstrated there was no clonal relationship among MRSA strains. No nasal carriers of MRSA were detected among health workers. During period B the rates of overall and MRSA infection were 2.36 and 0.19%, respectively. Both rates were statistically significantly lower than those in period A (p<0.05). These results suggest teicoplanin may be useful in patients undergoing orthopedic surgery when the prevalence of MRSA is high.