Radiographic Assessment of Bone Quality Using 4 Radiographic Indexes: Canal Diaphysis Ratio Is Superior.

BACKGROUND: Osteoporosis increases the risk of periprosthetic fracture and loosening in hip arthroplasty. Many methods have been proposed to assess bone quality in X-rays, including both qualitative such as the Dorr classification and quantitative such as the Calcar-Canal Ratio (CCR) and Cortical-Thickness index/Canal-Bone ratio (CTI/CBR). The Canal-Diaphysis ratio (CDR) has been described as a predictor for hip fragility fractures; however, its relationship with bone mineral density (BMD) has not been described. The purpose of this study was to evaluate the correlation of the Dorr classification, CCR, CTI/CBR, and CDR with BMD of the proximal femur in patients without hip fracture. METHODS: Forty-seven patients over 45 years of age who had less than 6 months between radiographs and dual-energy X-ray absorptiometry were evaluated. Measurements of CCR, CBR, CDR, and Dorr classification were performed in all radiographs by 2 independent observers. RESULTS: The CDR had a high correlation (r = 0.74, P=<0.01) with BMD, whereas the CTI/CBR had a moderate correlation (r = 0.49, P=<0.01), and the CCR had no correlation with BMD (r = 0.06, P = .96). When evaluating the receiver operating characteristic curve, CDR showed the best performance (area under curve [AUC] = 0.75) followed by CBR (AUC = 0.73) and CCR (AUC = 0.61). The optimal cutoff value for the CDR was 0.49, with 100% sensitivity and 58% specificity. The inter- and intra-observer variability was good for all methods. No differences were found between Dorr classification of patients who had or did not have osteoporosis. CONCLUSION: Of all the analyzed methods, the CDR was found to have the best correlation with BMD. This study proposes the use of CDR as a tool for assessing bone quality when deciding the implant fixation method in hip arthroplasty.

Diagnostic utility of open biopsy in patients with two culture-negative aspirations in the diagnostic work-up of periprosthetic joint infection.

INTRODUCTION: Different approaches have been proposed for bacterial identification in patients with a suspected periprosthetic joint infection (PJI). If a one-stage procedure is considered, a higher rate of preoperative bacterial identification can be achieved if biopsy is included in the diagnostic work-up. The performance of open biopsy (OB) in the context of PJI has not been clearly determined yet. The purpose of this study was to determine the value of an OB added to two consecutive culture-negative joint aspirations during PJI workup. MATERIALS AND METHODS: We retrospectively analyzed the OB data from a single institution. Patients under PJI work-up of the hip or knee with two culture-negative periprosthetic aspirations who underwent OB were included. Sensitivity and specificity were calculated using the musculoskeletal infection society (MSIS) criteria as gold standard. Patients undergoing urgent irrigation and debridement and patients with history of surgery to the affected joint in the prior 6 weeks were excluded. RESULTS: 126 patients were included in this study. 62 (49.2%) patients had prior revisions, 48 of them due to PJI. The sensitivity and specificity of OB was 69.4% and 89.1%, respectively. The OB procedure led to the identification of the causative germ in 50 out of 126 (40%) cases so they could undergo one-stage (septic) exchange. CONCLUSION: The OB is a valuable resource if preoperative synovial fluid cultures are negative, a high suspicion of infection persists and a one-stage procedure is preferred. It intends bacteria identification and allows surgeons to evaluate prosthetic complications for further surgical procedures.

What is the rate of successful closed reduction of dislocated dual mobility cups following complex revision hip arthroplasty?

PURPOSE: The aim of this study was to assess the difference in success rates of closed reduction in septic and aseptic revision total hip arthroplasty (THA) performed with a dual mobility (DM) implant. Our objective was to answer the following questions: (1) Is there a difference in success rates of closed reduction between septic and aseptic revision THA with a DM implant? (2) Is closed or open reduction more successful in preventing re-dislocation? METHODS: Between January 2009 and October 2021, 924 revisions were performed with a DM implant. All patients presenting to our institution with a dislocation following septic or aseptic revision THA using a cemented DM cup were included in this study. We analyzed 106 cases of dislocation in 74 patients. For all patients, we collected reason for revision, and classified index surgery as septic or aseptic. RESULTS: Overall, 106 dislocations occurred (106/924, 11.5%). Thirty-nine cases (52.7%) had a dislocation after a septic exchange THA, while in 35 patients (47.3%), a dislocation occurred after an aseptic rTHA. In 29 patients (39.2%), successful closed reduction under general anesthesia was feasible, while the majority of cases required open reduction. In 31 of these patients (67.4%), open reduction was combined with a revision arthroplasty. CONCLUSIONS: In case of DM cup dislocation, there is a low success rate of closed reduction. To prevent re-dislocation, total revision leads to a significantly reduced risk compared to open or closed reduction alone. Careful X-ray analysis for a halo sign showing intra-prosthetic DM cup dislocation is mandatory to avoid futile reduction attempts. LEVEL OF EVIDENCE: III.

[Implementation of a fracture liaison service. Experience with 177 patients]. / No Más Fracturas - Implementación de la primera Unidad de Coordinación de Fracturas en Chile: experiencia al año de funcionamiento.

BACKGROUND: Every year about 9 million fragility fractures (FF) occur worldwide and 80% of these are underdiagnosed or undertreated. Aiming to close the gap of diagnosis and treatment of osteoporosis, Fracture Liaison Services (FLS) were developed. AIM: To describe the implementation of the first FLS in Chile, its inclusion criteria, patient enrolment, treatment adherence and referrals during the first year. MATERIAL AND METHODS: A FLS was implemented at a health care network composed by two hospitals. The International Osteoporosis Foundation (IOF) guidelines were applied with a nurse practitioner as the coordinator. From May 2020 to April 2021 all patients diagnosed with a FF in the emergency rooms were invited to participate. Patients with pathological fractures and active cancer were excluded. Demographical data, fracture location, previous fractures, treatment and adherence, and mortality were recorded. RESULTS: From 443 patients with a diagnosis of FF, 177 patients (40%) accepted to participate. Their mean age was 74 ± 13 years and 84% (149) were female. Forty eight percent (84) had a lower extremity FF. Hip fractures were the most common (67). Ninety-five patients reported previous FF and 11,2% (20) had received anti-osteoporotic treatment. At four months of follow-up, 62% (50) had received vitamin D and calcium supplementation and 20% (16) of those patients with an indication of anti-osteoporotic drugs, had received them. CONCLUSIONS: The implementation of the FLS was successful with a 40% enrolment of patients, receiving certification by the IOF.

A novel intraoperative technique seeding morselized bone tissue into pediatric blood culture bottles improves microbiological diagnosis in patients with foot and ankle osteomyelitis.

BACKGROUND: Osteomyelitis, particularly cases involving the foot and ankle, is a challenging situation that frequently leads to amputations and major sequelae. Targeted antibiotics treating an identified pathogen are key to a successful outcome; however, traditional culture methods for bone tissue have poor sensitivity. This study prospectively compared a novel method for obtaining and processing infected bone tissue with the standard technique. METHODS: 107 patients presenting with a diagnosis of osteomyelitis of the foot and ankle between 2008 and 2017 were prospectively included. Diagnosis was done according to clinical, laboratory and imaging findings. We obtained paired samples of bone tissue from all patients; they were processed through a usual culture method (UCM), but they were also morselized and seeded into pediatric blood culture bottles (PBCBs). We compared the culture yield and the number of agents detected using both the McNemar and the Mann-Whitney tests, respectively. RESULTS: We studied 107 patients (63 with diabetic foot infection and 44 with nondiabetic osteomyelitis). The causative agent was identified in 60.7% of cases using the UCM and in 97.2% of cases using PBCBs (p < 0.001). We detected a mean of 1.05 ± 1.03 bacteria using the UCM and 1.67 ± 0.92 bacteria using PBCBs (p < 0.01). CONCLUSION: Cultures using morselized bone seeded in PBCBs identified the causative agent in a significantly larger percentage than the UCM. Additionally, this method identified a larger number of pathogen agents. A better agent identification method has advantages such as identifying more specific antibiotic treatment in these cases.

Ten-Year Results Following One-Stage Septic Hip Exchange in the Management of Periprosthetic Joint Infection.

BACKGROUND: Although 2-stage revision is still considered the gold standard for surgical management of periprosthetic joint infection (PJI), 1-stage revision has been reported to be as effective. Long-term reports for 1-stage revision in hip PJIs are lacking. METHODS: We reviewed our 10-11 years of results of 85 patients who underwent 1-stage exchange of the hip with an antibiotic-loaded bone cemented prosthesis due to PJI to determine the following: (1) What is the infection-free survival? (2) What is the overall survival? and (3) What are the long-term clinical outcomes? All 1-stage revision total hip arthroplasties (THAs) for infection between January 2006 and December 2007, with a minimum 10-year follow-up (range 10-11), were included in this retrospective cohort. Patients from another country or patients who were unable to participate were excluded. Eighty-five patients with a hip PJI were available at the last follow-up. Thirty-seven patients died during the 10-year study. Harris Hip Scores were recorded before the surgery and at last follow-up. Failures are reported as infection-related or aseptic. RESULTS: The 10-year infection-free survival was 94% and the surgery-free survival was 75.9%. The Harris Hip Scores improved from 43 (range 3-91) to 75 (range 10-91) (P < .001). The main indication for re-revision after 1-stage exchange was instability (10/20 patients). CONCLUSION: One-stage exchange of the hip for PJI is a reliable treatment option with high rate of infection control and long-lasting favorable outcomes.

Contamination rate of the surgical gowns during total hip arthroplasty.

INTRODUCTION: Surgical instrument contamination during total joint replacement is a matter of major concern. Available recommendations suggest changing suction tips, gloves and avoiding light handle manipulation during the procedure. There is a paucity of data regarding surgical gown contamination. The aim of the present study was to evaluate the contamination rate of surgical gowns (SGs) during total hip arthroplasty (THA) and secondarily compare it with other orthopedic procedures. MATERIALS AND METHODS: One hundred and forty surgical gowns (from 70 surgeries) were screened for bacterial contamination using thioglycolate (a high-sensitivity culture broth). The THA contamination rate was compared with those of knee and spine procedures. Controls were obtained at the beginning of every surgery and from the culture broth. The procedure's duration and the level of training of the surgeon were evaluated as potential risk factors for contamination. RESULTS: Bacterial contamination was identified on 12% of surgical gowns (22% of surgical procedures). The contamination rate during THA was 4.1% (2% in primary THA and 8.3% in revisions) vs 21.67% during other surgeries (spine and knee) (OR 6.15, p = 0.012). There were no contaminated SGs during THAs performed in ≤ 2 h (0/33 SGs) vs 7.5% (3/40) for THAs that took ≥ 2 h (p = 0.25). CONCLUSION: There was a high rate of SG contamination during orthopedic procedures that was higher during non-arthroplasty procedures and prolonged THAs. There were no contaminated surgical gowns in THAs under 120 min, efforts should point keeping primary THAs under this cutoff time. As a general recommendation, SGs should be changed every time there is concern about potential contamination.

[Management of hip fractures in the elderly. A national survey among Chilean orthopaedic surgeons]. / Controversias en el manejo de la fractura de cadera en el adulto mayor. Encuesta nacional a Traumatólogos especialistas en cirugía de cadera.

BACKGROUND: As the population ages, patients exposed to osteoporotic fractures increase, especially hip fracture, which is the most severe and costly. AIM: To characterize surgical practices in the management of hip fractures in older patients through a nationwide survey of specialized hip surgeons dedicated to the care of these patients. MATERIAL AND METHODS: A survey composed of 32 questions was formulated, including demographic factors, preoperative evaluation, definitive treatment, and postoperative management. It was sent to 140 specialists. 84 of them replied (61%), and 71 answers were included. RESULTS: Eighty six percent of respondents agreed that orthogeriatric management is fundamental in the outcome of these patients, but only 73% had the collaboration of an internist or a geriatrician. Although 97% considered 72 hours or less the ideal time to perform surgery, only 52% of the respondents declared performing surgery within that timeframe, with differences between private and public system. Regarding surgical treatment, 94-98% of femoral neck fractures are treated with an arthroplasty and 98-99% of per-subtrochanteric fractures are treated with internal fixation and osteosynthesis. Osteoporosis treatment is only carried out by 51% of the respondents and with significant variation. CONCLUSIONS: This survey shows that there is agreement in surgical practice between specialists treating these patients, but clear differences in preoperative optimization, treatment timeframe, and post fracture medical treatment.

Successful initial experience with a novel outpatient total hip arthroplasty program in a public health system in Chile.

PURPOSE: The aim of the present study was to assess the first experience with outpatient total hip arthroplasty (THA) in a public health environment in Chile. METHODS: Prospective series of the first 69 patients/72 hips. Surgery was performed in a public university-affiliated hospital. The patients were 64 (31-84) years old and healthy (ASA I-II) candidates for a primary hip arthroplasty. RESULTS: The outpatient track had 52.2% of arthroplasty candidates included and 94.4% (68/72 hips) were successfully discharged the same day. There were no emergency room visits during the first week after surgery. Two patients had single dislocation episodes, one requiring stem revision. There was one deep vein thrombosis. There were no other complications. All the patients reported to be satisfied with the outpatient track. INTERPRETATION: An outpatient track can be developed in a safe manner in this healthcare setting and population. This track of care was well accepted by the patients.

[Perioperative care of older patients with hip fractures]. / Optimización perioperatoria del paciente anciano con fractura osteoporótica de cadera.

The number of osteoporotic fractures is increasing along with population aging. Most patients with these type of fractures are older than 65 years, with multiple chronic conditions and different degrees of disability. Hip fracture is the most relevant osteoporotic fracture due to its frequency, costs, severity and complications. Multidisciplinary management is of the utmost importance to obtain good therapeutic results. We herein review the management of this fracture. Orthogeriatric joint management should be incorporated in fragility fracture treatment. We contribute with general recommendations for the perioperative management, which can be homologated for the management of older patients with other type of fragility fractures.

[Vitamin D levels among Chilean older subjects with low energy hip fracture]. / Prevalencia de insuficiencia y deficiencia de vitamina D en adultos mayores con fractura de cadera en Chile.

BACKGROUND: Vitamin D deficiency is a common condition affecting 40-100% of geriatric population. AIM: To determine the prevalence of vitamin D insufficiency and deficiency in geriatric population surgically treated for hip fracture. PATIENTS AND METHODS: Analysis of a database of patients aged over 60 years operated for a low energy hip fracture in a three years period. Vitamin D was measured in identified patients, using a blood sample obtained on admission to the hospital. A logistic regression was carried out to evaluate age, gender, morbidity index and season as predictors of vitamin D deficiency. RESULTS: Two hundred and twenty-eight patients aged 84 ± 7 years (82% females), were included in the analysis. One hundred eighty-three patients (80%) presented vitamin D levels below 20 ng/dl (deficiency) and 39 patients (18%) presented with levels between 20 and 30 ng/dl (insufficiency), totaling 98% of patients with hypovitaminosis D. Vitamin D deficiency was especially common among patients with higher American Society of Anesthesiologists (ASA) Physical Status Classification System and during winter-spring period. A negative correlation between age and the proportion of subjects with vitamin D deficiency was found. There was no relation between gender and vitamin D levels. CONCLUSIONS: Vitamin D deficiency is especially prevalent in older subjects with hip fracture, reaching 98% in the studied population.

Inter- and intra-observer agreement using the new AOSpine sacral fracture classification, with a comparison between spine and pelvic trauma surgeons.

BACKGROUND: Sacral fractures treatment frequently involves both spine and pelvic trauma surgeons; therefore, a consistent communication among surgical specialists is required. We independently assessed the new AOSpine sacral fracture classification's agreement from the perspective of spine and pelvic trauma surgeons. METHODS: Complete computerized tomography (CT) scans of 80 patients with sacral fractures were selected and classified using the new AOSpine sacral classification system by six spine surgeons and three pelvic trauma surgeons. After four weeks, the 80 cases were presented and reassessed by the same raters in a new random sequence. The Kappa coefficient (κ) was used to measure the inter-and intra-observer agreement. RESULTS: The inter-observer agreement considering the fracture severity types (A, B, or C) was substantial for spine surgeons (κ= 0.68 [0.63 - 0.72]) and pelvic trauma surgeons (κ= 0.74 (0.64 - 0.84). Regarding the subtypes, both groups achieved moderate agreement with κ= 0.52 (0.49 - 0.54) for spine surgeons and κ= 0.51 (0.45 - 0.57) for pelvic trauma surgeons. The intra-observer agreement considering the fracture types was substantial for spine surgeons (κ= 0.74 [0.63 - 0.75]) and almost perfect for pelvic trauma surgeons (κ= 0.84 [0.74 - 0.93]). Concerning the subtypes, both groups achieved substantial agreement with, κ= 0.61 (0.56 - 0.67) for spine surgeons and κ= 0.68 (0.62 - 0.74) for pelvic trauma surgeons. CONCLUSION: This classification allows an adequate communication for spine surgeons and pelvic trauma surgeons at the fracture severity type, but the agreement is only moderate at the subtype level. Future prospective studies are required to evaluate whether this classification allows for treatment recommendations and establishing prognosis in patients with sacral fractures.

The new AO classification system for intertrochanteric fractures allows better agreement than the original AO classification. An inter- and intra-observer agreement evaluation.

BACKGROUND: A new AO classification for intertrochanteric fractures was recently published; no studies have evaluated its inter- and intra-observer agreement. METHODS: Six evaluators (three hip subspecialists and three residents) assessed radiographs of 68 intertrochanteric fractures; fractures were classified using the original and the new AO classifications. The cases were displayed in a random sequence after a six-week interval for repeat evaluation. We used the Kappa coefficient (k) to determine inter- and intra-observer agreement. RESULTS: Inter-observer agreement was slight (k = 0.128 [0.092-0.170]) using the original and fair (k = 0.250 [0.186-0.327]), with the new AO classification. Orthopedic residents exhibited better agreement than hip surgeons using the original classification (k = 0.302 [0.210-0.416] and k= -0.018 [-0.058-0.029], respectively) and the new classification (k = 0.388 [0.294-0.514] and k = 0.109 [0.031-0.192], respectively). Using both classifications as dichotomous variables (stable or unstable patterns), the agreement was slight (k = 0.158 [0.074-0.246]) using the original classification and moderate (k = 0.425 [0.308-0.550]) with the new AO classification. INTRA-OBSERVER: The agreement was fair using the original (k = 0.350 [0.278-0.424]) and the new (k = 0.295 [0.239 to 0.353]) AO classifications, respectively. Residents had better agreement than hip specialists using the original (k = 0.405 [0.303-0.512]) versus (k = 0.292 [0.193-0.293]) and the new classification (k = 0.449 [0.370 to 0.528] versus k = 0.129 [0.064 to 0.208]). CONCLUSION: The inter-observer agreement using the new AO classification was significantly better than using its original version. Also, the new AO classification system allowed better agreement when distinguishing stable from unstable patterns.

Hip Fractures in the Elderly During the COVID-19 Pandemic: A Latin-American Perspective With a Minimum 90-Day Follow-Up.

INTRODUCTION: Hip fracture patients have been severely affected by the COVID-19 pandemic; however, the sub acute effects of a concomitant SARS-CoV-2 infection and the outcomes in highly exposed developing countries are still unknown. Our objective is to describe the morbidity and mortality of elderly patients admitted for a hip fracture during the COVID-19 pandemic in Chile, with a minimum 90-day follow-up. Also, to elucidate predictors for mortality and to compare mortality results with the pre-pandemic era. MATERIAL AND METHODS: Multicentric retrospective review of patients admitted for a fragility hip fracture in 3 hospitals during the COVID-19 pandemic, and during the same time in 2019. All clinical information and images were recorded, and patients were followed for a minimum of 90-days. Morbidity and mortality were the primary outcomes. Uni/multivariable models were performed to elucidate predictors for mortality utilizing the Weibull's regression. RESULTS: Three hundred ninety-one cases were included. From the 2020 cohort (162 patients), 24 (15%) had a concomitant SARS-CoV-2 infection. Fourteen patients (58%) tested positive after admission. The COVID-19(+) group had a higher risk of in-hospital, 30-day, and 90-day mortality (p < 0.001). They also had a prolonged hospital stay and presented with more complications and readmissions (p < 0.05). Only COVID-19(+) status and older age were independent predictors for mortality with a HR = 6.5 (p = < 0.001) and 1.09 (p = 0.001), respectively. The 2020 cohort had twice the risk of mortality with a HR = 2.04 (p = 0.002) compared to the 2019 cohort. However, comparing only the COVID-19 (-) patients, there was no difference in mortality risk, with a HR = 1.30 (p = 0.343). DISCUSSION: The COVID-19 pandemic has significantly affected healthcare systems and elderly patients. CONCLUSIONS: Hip fracture patients with a concomitant SARS-CoV-2 virus infection were associated with increased morbidity and mortality throughout the first 3 months. COVID-19 status and older age were significant predictors for mortality. Efforts should be directed into nosocomial infection reduction and prompt surgical management. LEVEL OF EVIDENCE: Level III.

Polyostotic fibrous dysplasia (McCune-Albright) with rare multiple epiphyseal lesions in association with aneurysmal bone cyst and pathologic fracture.

Fibrous dysplasia, including McCune-Albright syndrome, is a genetic, non-inheritable benign bone disorder that may involve a single or multiple bone, typically occurring in the diaphysis or the metaphysis of long bones. In very rare instances polyostotic fibrous dysplasia present involvement of the epiphysis in long bones. Aneurysmal bone cysts are benign, expansile, lytic bone lesions formed by cystic cavities containing blood, that may occur de novo or secondary to other lesions of bone, including fibrous dysplasia. We report a case of an 18-year-old female with polyostotic fibrous dysplasia (McCune-Albright syndrome) with diaphyseal and unusual multiple foci of epiphyseal involvement of long bones as well as in the patella, and a simultaneous aneurysmal bone cyst of the left femoral neck with pathologic fracture. This is the first report of a simultaneous aneurysmal bone cyst in a patient with polyostotic fibrous dysplasia (McCune-Albright syndrome) with involvement of diaphysis and epiphysis of long bones, highlighting that fibrous dysplasia should be included in the differential diagnosis of polyostotic tumors involving the diaphysis as well as the epiphysis. In patients with polyostotic fibrous dysplasia there should be an active search for lesions in the epiphysis.

Clostridium histolyticum (AA4500) for the Treatment of Adhesive Capsulitis of the Shoulder: A Randomised Double-Blind, Placebo-Controlled Study for the Safety and Efficacy of Collagenase - Single Site Report.

BACKGROUND/HYPOTHESIS: Adhesive capsulitis of the shoulder results in pain and restricted movement of the glenohumeral joint. Hypothesis: There would be a difference in active range of movement in the affected shoulder of patients with adhesive capsulitis after receiving a series of injections of collagenase Clostridium histolyticum (CCH) compared to placebo. METHODS: This study reports the results from a single site that was part of a 321-participant, multicenter, double-blind, prospective parallel-group, randomized controlled clinical trial. Inclusion criteria: over 18 years of age, unilateral idiopathic adhesive capsulitis for >3 months, but <12 months. Exclusion criteria: recent physical therapy, injections, subacromial impingement, calcific tendonitis or glenohumeral joint arthritis in the affected shoulder. Subjects were randomized 3:1 to receive CCH 0.58 mg or placebo under ultrasound guidance. Injections were on days 1, 22, and 43. The primary outcome measure was a functional assessment of active range of movement. RESULTS: Overall, 37 patients were screened, 26 subjects were excluded, and 11 subjects were randomly assigned to the treatment group (n=9) or the control group (n=2). Both control and treatment groups showed improvement in ROM between baseline and day 95. In the treatment group, AROM improved from the baseline of 272.89° (SD 86.25) to 462.11° (SD 96.89) and the control group from 246.00° (SD 5.66) to 451.50° (SD 50.20) at day 95 with no statistical difference between groups p=0.78. Site data were in line with the whole study findings. Treatment-related adverse events at the injection site, including haematoma (bruising) and localised pain and swelling, were common. CONCLUSION: Although the participants showed improvement in function, statistical significance was neither reached in the site nor the overall study cohort. Given the adverse events and the potential risks of the procedure, we would not recommend this drug for the treatment of adhesive capsulitis of the shoulder. LEVEL OF EVIDENCE: 2, cohort from one site of RCT.

Methicillin-resistant Staphylococcus aureus colonization in patients undergoing primary total hip arthroplasty.

Introduction. Nasal and skin colonization by methicillin-resistant Staphylococcus aureus (MRSA) are linked to a higher incidence of infection after total joint replacement. The prevalence of colonization is poorly defined in Latin American countries.Aim. The aim of the present study was to determine the prevalence of MRSA colonization in the nostrils and groin using real-time polymerase chain reaction (RT-PCR) in patients undergoing total hip arthroplasty (THA).Methodology. In this cross-sectional study, 146 patients undergoing THA between December 2015 and March 2017 in a tertiary-care university-affiliated hospital in Chile were screened for MRSA colonization before the procedure using RT-PCR independently in the nostrils and groin. Risk factors for colonization were documented.Results. Seven of the 146 (5 %) patients undergoing THA were carriers of MRSA in the nostrils and/or the groin. Recent antibiotic use was identified as a risk factor for colonization, OR=4.86 [95 % confidence interval (CI): 1.56-13.96]. Patients reporting at least one of the seven surveyed risk factors had an OR of 2.39 (95 % CI: 0.37-25.77) for colonization. MRSA colonization frequency was twofold higher in the groin as opposed to the nostrils (P=0.014).Conclusion. Five percent of the patients undergoing THA were identified as carriers of MRSA. Recent antibiotic use is a relevant risk factor for MRSA colonization in patients undergoing primary total hip arthroplasty.