First record of the black twig borer, Xylosandrus compactus (Coleoptera: Curculionidae, Scolytinae) in Spain.

We present the first record for Spain of the black twig borer, Xylosandrus compactus, an ambrosia beetle of Asian origin, collected from an infested carob tree located in Calvià (Majorca, Balearic Islands, Spain). X. compactus is included in the EPPO Alert List, and it has been recently reported causing damages in a Mediterranean maquis ecosystem in Italy and Southern France. Here, we discuss about the first steps of management of this Invasive Alien species (IAS), the eradication plan and the hypothesis of the path of introduction in this Western Mediterranean island.

Early clinical and radiological outcomes for the Taperloc Complete Microplasty stem.

The use of short stem designs in total hip arthroplasty is not a new concept, but its popularity has increased as a bone-sparing alternative to traditional stems. This study analyzed the midterm clinical and radiological results of the Taperloc Complete Microplasty stem (Zimmer Biomet® Warsaw, IN, USA). A total of 32 patients (20 men and 12 women) were retrospectively documented and received 40 stems (eight bilateral). The median patient age was 50 years (interquartile range 43-58) at the time of surgery. The median follow-up was 36.5 months (interquartile range 26.75-50.25). Indication for total hip arthroplasty was osteoarthritis (62.5% of patients), avascular necrosis (25%), and developmental dysplasia of the hip (12.5%). The Merle d'Aubigné score improved from a mean 11.5 preoperatively to a mean 17.5 at the latest follow-up. During X-ray assessment, we observed one subsidence of the stem (3 mm) and four cases of varus malalignment without clinical consequences. No cases of osteolysis were reported, and no stems were revised. According to our results, this short tapered stem shows a good early-term outcome. Prospective results and a longer follow-up are needed to assess the long-term survival of this stem fully.

Relationship between femoral offset and dislocation in preformed antibiotic-loaded cement spacers (Spacer-G®).

INTRODUCTION: A reduction in femoral offset may decrease muscle tension and lead to spacer dislocations even though proximal femur, musculature and acetabulum remain intact. In this study, we aimed to determine whether postoperative lateral femoral offset (LFO) and modified vertical femoral offset (MVFO) values affect the risk of dislocation of a hip spacer. MATERIALS AND METHODS: We measured LFO and MVFO in properly centred, postoperative, anteroposterior radiographs of the pelvis in 66 patients (71 spacers). We then compared the operated and non-operated sides and recorded any dislocations. RESULTS: Although LFO decreased (p<0.001), the reduction was not associated with dislocation (p = 0.471). MVFO remained unchanged after spacer implantation (p = 0.277) and was not associated with dislocation (p = 0.418). CONCLUSIONS: In conclusion, the preformed spacer decreased LFO but not MVFO compared with the contralateral hip. The variations did not significantly affect the dislocation rate.

Trabecular TitaniumTM cups and augments in revision total hip arthroplasty: clinical results, radiology and survival outcomes.

BACKGROUND: Large acetabular defects remain a challenge in hip revision arthroplasty. Experience with Trabecular Titanium™ (TT) cups (Limacorporate S.p.a.) has not been widely reported. Therefore, we assessed the survivorship and clinical and radiological outcomes of patients receiving TT cups, with or without supplementary trabecular titanium hemispherical modules for acetabular reconstruction, in primary and revision total hip arthroplasty (THA). METHODS: Between January 2009 and July 2014, we performed 67 revisions and 5 primary THAs using TT cups in 69 patients. To achieve stability and/or restore the hip's centre of rotation, hemispherical modules were used in 17 cases based on preoperative templating and/or intraoperative findings. Mean follow-up was 30.5 months. Acetabular bone defects were classified according to the Paprosky classification. Survivorship, functional outcomes (Merle d'Aubigné) and radiological outcomes were analysed. RESULTS: 8 patients underwent cup revision: 2 for loosening, 3 for infection, and 3 for hip dislocation. The remaining cases did not present radiological signs of loosening. None of the cases with Paprosky type I classifications needed revision, while 4 with type II and 4 with type III needed revision (p = 0.028). The respective mean values for pain, walking, and range of motion (Merle d'Aubigné scores ± standard deviation) were 3.6 ± 1.4, 3.7 ± 0.7, and 3.8 ± 0.6 preoperatively, and 5.7 ± 0.7, 5.3 ± 0.7, and 5.6 ± 0.7 at the latest follow-up (p<0.001). CONCLUSIONS: In the short term, results with TT cups appear to be encouraging, with satisfactory survival rates for both simple and complex cases.

Radiography versus multidetector computed tomography in assessing graft integration after acetabular reconstruction.

PURPOSE: To compare radiography with multidetector computed tomography (MDCT) in the evaluation of graft integration following acetabular reconstruction for failed total hip arthroplasty (THA). METHODS: Records of 5 men and 6 women aged 60 to 78 (mean, 71.8) years who underwent acetabular reconstruction using structural allografts for severe acetabular deficiency secondary to aseptic loosening (n=9) or septic loosening (n=2) were reviewed. The mean survival time of the THA was 136.4 (range, 12-360) months. Acetabular defects were classified as IIC (n=2), IIIA (n=3), or IIIB (n=6). Structural allografts were fixed with impaction followed by a reinforcement ring (n=10), an antiprotrusio cage (n=2), and/or an oblong cup (n=1) with gentamicineloaded cement. Cup loosening, graft integration, and graft resorption were evaluated using radiography. In addition, graft integration was evaluated using MDCT. RESULTS: At a mean follow-up of 4.2 (range, 2-11) years, the survival of the acetabular reconstruction was 90.9%. No patient had any signs of infection. One patient underwent reoperation 22 months later for dislocation secondary to abductor deficiency caused by nonunion of the trochanteric fracture. According to radiography, all patients had graft integration. One patient had definitive and another had possible cup loosening. Four patients had minor graft resorption. According to MDCT, graft integration was complete in only one patient, partial >50% in 3, partial <50% in 4, and absent in 2. CONCLUSION: MDCT is more accurate than radiography in evaluating graft integration following acetabular reconstruction.

Calidad del informe de alta hospitalaria realizado por médicos internos residentes de especialidades quirúrgicas / Quality of hospital discharge report conducted by surgical resident physicians

Introducción: Los médicos internos residentes (MIR) deben adquirir competencia en la correcta redacción del informe de alta hospitalaria (IAH). Este documento debe contener un conjunto de datos mínimos y ha de ser comprensible para el paciente, su médico de familia u otros profesionales. El proceso de adquisición de esta competencia ha sido poco estudiado y la calidad de los IAH firmados por MIR no se ha evaluado previamente. Sujetos y métodos: El presente estudio ha evaluado la calidad de 124 IAH de urgencias comparando aquellos firmados por especialistas, firmados únicamente por MIR o firmados por MIR y especialista, en las especialidades de cirugía ortopé- dica y traumatología y de cirugía general. Resultados: El resultado ha sido más favorable que el de publicaciones previas, con una puntuación superior a 7 sobre 10 en el 94,4% de los casos. Además, los IAH realizados por residentes de primer año y supervisados por especialistas han sido los informes con mejor puntuación, con diferencias estadísticamente significativas (p = 0,003). No se observaron diferencias estadísticamente significativas entre los informes redactados por la mañana respecto de los redactados por la madrugada (p = 0,6). En cuanto a los contenidos, un 12,9% de los informes presentaba siglas de difícil comprensión. Conclusión: Nuestro estudio objetiva el efecto beneficioso de la supervisión del IAH en el primer año de residencia, al igual que se identifica un objetivo de mejora consistente en minimizar el uso de siglas médicas

Introduction: Resident intern physicians (MIR) must become competent in writing correct hospital discharge reports (HDR). This document must contain a minimum data set, and should be understandable to the patient, family doctor or other professionals. The acquisition of this competence has been little studied, and the quality of HDRs performed by MIR has not been previously evaluated. Subjects and methods: The present study evaluated the quality of 124 emergency HDRs comparing those signed by specialists, only signed or signed by MIR, or signed by MIR and specialist in the fields of Orthopaedic Surgery and General Surgery. Results: The result has been more favourable than that of previous publications, with a score of 7 out of 10 in 94.4 % of cases. HDRs made by first-year residents and supervised by specialists obtained the best scores with statistically significant differences (p = 0.003). No differences were observed between the reports by the morning or night (p = 0.6). In terms of content, 12.9% of reports had acronyms difficult to understand. Conclusion: Our study depicts the beneficial effect of HDR monitoring in the first year of residency as well as an improvement objective by minimizing the use of medical abbreviations

Mobility and efficacy of abamectin and imidacloprid against Rhynchophorus ferrugineus in Phoenix canariensis by different application methods.

BACKGROUND: Rhynchophorus ferrugineus is the most destructive pest of palms. As detection of early infestation stages is difficult, preventive measures, mostly chemical control, are crucial. Stipe injection of insecticides has developed rapidly as a suitable technique. However, pesticide movement within palms and palm reaction to wounding remain controversial. We used abamectin and imidacloprid applied by crown spray, stipe and frond injections to disentangle how these pesticides move within P. canariensis and how tissues wounded by injection heal. Furthermore, we established their lethal doses to larvae of R. ferrugineus. RESULTS: Maximum residues of imidacloprid (0.1 mg kg(-1) ) were detected in crown and frond samples for up to 2 months after stipe injection, whereas maximum residues of abamectin were found in frond tip samples (0.5 mg active substance kg(-1) ) 5 months after stipe injection. Based on the lethal concentrations calculated, these doses could satisfactorily protect palms for up to 3 months after treatment. No significant wound damage was observed 2 years after injection. CONCLUSION: Stipe injection, irrespective of the active substance considered, resulted in better distribution and higher persistence compared with frond injection and, especially, crown spray. As a consequence, our results point to stipe injection as a good alternative to control R. ferrugineus.

Field trapping of the flathead oak borer Coroebus undatus (Coleoptera: Buprestidae) with different traps and volatile lures.

The flathead oak borer Coroebus undatus F. (Coleoptera: Buprestidae) is one of the primary pests of cork oak Quercus suber L. in the Mediterranean region causing great economic losses to the cork industry. Very little is known about its biology and behavior and, so far, no control measures have been established. We present the results of a pilot study aimed to develop an efficient trapping method for monitoring this harmful pest. In a 3-year field study, purple-colored prism traps baited with a mixture of green leaf volatiles (GLVs) from the host have been shown the most effective combination to catch C. undatus adults (solely females) compared to other trap and lure types tested. Wavelength and reflectance measurements revealed that purple traps exhibit reflectance peak values similar to those found in the abdominal and elytral cuticle of both sexes, suggesting the involvement of visual cues for mate location in this species. The data presented are the first to demonstrate captures of adults of the genus Coroebus by an attractant-based trapping method.

Assessment of Patients with a DePuy ASR Metal-on-Metal Hip Replacement: Results of Applying the Guidelines of the Spanish Society of Hip Surgery in a Tertiary Referral Hospital.

The prognosis associated with the DePuy ASR hip cup is poor and varies according to the series. This implant was withdrawn from use in 2010 and all patients needed to be assessed. We present the results of the assessment of our patients treated with this device, according to the Spanish Society of Hip Surgery (SECCA) algorithm published in 2011. This retrospective study evaluates 83 consecutive ASR cups, followed up at a mean of 2.9 years. Serum levels of chromium and cobalt, as well as the acetabular abduction angle, were determined in order to assess their possible correlation with failure, defined as the need for revision surgery. The mean Harris Hip Score was 83.2 (range 42-97). Eight arthroplasties (13.3%) required revision due to persistent pain and/or elevated serum levels of chromium/cobalt. All the cups had a correct abduction angle, and there was no correlation between elevated serum levels of metal ions and implant failure. Since two previous ASR implants were exchanged previously to the recall, the revision rate for ASR cups in our centre is 18.2% at 2.9 years.

Special issues involving periprosthetic infection in immunodeficiency patients.

Chronic systemic illnesses such as diabetes mellitus, chronic kidney disease (CKD), liver cirrhosis, neoplasia, etc. have been clearly associated with high rates of SWI. However, the exact mechanisms underlying these observations are still under investigation. Chronic kidney disease (CKD) is a growing problem in our society. Many of these patients will require an arthroplasty and it appears that the prosthetic infection risk for these types of patients is much higher than in the normal population. The risk of complications due to infection seems to be lower in patients with kidney transplants than in patients undergoing haemodialysis. Both prophylaxis and treatment of infection in patients with CKD should be carried out with a strict monitoring of potentially nephrotoxic antibiotics. The literature on the prognosis and risk of infection in patients with haematopoietic stem cell transplant is scarce and occasionally contradictory. The optimal time for the surgery should be determined by taking into account the immunological state of the patient and should be avoided, as much as possible, during the first year after the HSCT. Child's classification system is the most widely used method of stratifying the surgical risk for patients with cirrhosis; the infection appeared to be associated in a statistically significant way with advanced age and a Child B pre-operative classification. The prevention of prosthetic joint infections in HIV-infected patients should not be significantly different from the prevention for any other patient. Those patients that receive adequate antiretroviral treatment and periodic laboratory control show infection rates and periprosthetic complications that are similar to those for patients not affected by HIV. Therefore, the patient's level of immunodeficiency is the most important prognostic factor for prosthetic infection. The particular immunological condition of these patients can lead to infections due to particular microorganisms that immunocompetent patients do not have to deal with. Of all possibilities, because of their frequency and difficulty to treat, infections caused by methicillin-resistant S. aureus and fungus are highlighted.

Usefulness of histology for predicting infection at the time of hip revision for the treatment of Vancouver B2 periprosthetic fractures.

When facing a Vancouver B2 periprosthetic fracture, the most recommended treatment is the prosthesis replacement. Current tests do not provide enough reliability to identify whether the fracture has been produced on a septic or an aseptic loosened prosthesis. Our aim was to evaluate the usefulness of the histology for the diagnosis of infection in these cases. A total of 11 hip revision procedures were performed (mean age: 78.1 years, 8 women and 3 men). Sensitivity, specificity, positive predictive value and negative predictive value of the histology were 100%, 55.5%, 33.3% and 100% respectively. Of the six patients presenting with a positive histology, four of them had negative cultures (66.6% of false positives). Our results suggest that periprosthetic fractures are a cause of false-positive histology results for the diagnosis of infection during revision of a hip prosthesis for the treatment of Vancouver B2 periprosthetic fractures.

Relationship between the degree of osteolysis and cultures obtained by sonication of the prostheses in patients with aseptic loosening of a hip or knee arthroplasty.

INTRODUCTION: The pathogenesis of prosthesis loosening is not well understood. The aim of our study was to sonicate components of joint prostheses removed due to aseptic loosening, culture the sonicate fluid, and to correlate these results with the degree of radiological osteolysis. METHODS: From January 2008 to June 2009 all consecutive patients who underwent a revision of hip or knee prosthesis due to aseptic loosening were included in the study. Aseptic loosening was established when the patient had radiological signs of loosening without symptoms or signs of infection. The diagnosis was confirmed when histology was negative, and ≥ 5 out of 6 standard cultures of periprosthetic tissue were negative. Bone lysis was measured according to the Paprosky or Engh classifications without knowing the result of sonication cultures. Removed components were placed in sterile bags and immediately transported to the microbiology laboratory and sonicated. Sonicate fluid was cultured and the results were correlated with the degree of bone lysis. The proportion of components with positive sonication culture according to the bone lysis classification was compared using χ(2) test. RESULTS: A total of 52 patients were included and 123 components were sonicated. In 30 patients at least 1 sonicated component was positive (57.7%) and 44 out of 123 (35.8%) components were positive. The proportion of positive sonication cultures was significantly higher in the group of components with a higher degree of bone lysis of 3 (76.5%) than in those with lower degrees (33.9% for 1 and 24% for 2) (χ(2) test, p = 0.0004). CONCLUSIONS: Sonication cultures were positive in 57% of patients who underwent revision arthroplasty for aseptic loosening. The percentage of positive sonication cultures was significantly higher in patients with severe osteolysis. LEVEL OF EVIDENCE: level I of Prognostic Studies-Investigating the Effect of a Patient Characteristic on the Outcome of Disease.

Accuracy of CT-guided joint aspiration in patients with suspected infection status post-total hip arthroplasty.

OBJECTIVE: To determine the accuracy of guided computed tomography aspiration in the detection of septic hip prosthesis before surgery. MATERIALS AND METHODS: Sixty-three patients (35 women and 28 men; age range, 29-86 years; mean age, 71 years) with clinically suspected septic hip prosthesis were prospectively studied with independent review board (IRB) approval. Volume and microbiological cultures of aspirated fluid and several computed tomography imaging findings such as periprosthetic fluid collections, prosthetic acetabular malposition, and heterotopic ossification were analyzed. All patients underwent revision surgery and infection was finally diagnosed in 33 patients. RESULTS: Statistical comparative analysis was performed comparing computed tomography aspiration and surgical findings (95% CI; level of significance at P=0.05 two-sided) with 70% sensitivity, 100% specificity, 84% accuracy, 100% positive predictive value, and 75% negative predictive value. Using Fisher's exact test, the presence of periprosthetic fluid collections (P=0.001), prosthetic acetabular malposition (P=0.025) and aspirated fluid volume (P=0.009) were significantly higher in infected than in non-infected prostheses, whereas heterotopic ossification was not (P=0.429). CONCLUSION: Computed tomography aspiration is accurate to preoperatively diagnose septic hip prosthesis on the basis of volume and bacterial cultures of aspirated joint fluid. Furthermore, imaging findings such as periprosthetic fluid collections and prosthetic acetabular malposition strongly suggest infected prosthesis.

Interface membrane is the best sample for histological study to diagnose prosthetic joint infection.

The objective of our study was to study which is the most accurate specimen for histological diagnosis of prosthetic joint infections (pseudocapsule or interface membrane). This is a prospective study including hip revision arthroplasties performed from January 2007 to June 2009. Specimens from pseudocapsule and from interface membrane were obtained from each patient. The histology was considered positive for infection when ≥5 neutrophils per high-power field ( × 40) were found. Definitive diagnosis of infection was considered when ≥2 cultures were positive for the same microorganism. According to the definition of infection, patients were classified in two groups: (A) patients with aseptic loosening in whom cultures obtained during surgery were negative and (B) patients with prosthetic joint infection. A total of 69 revisions were included in the study; 57 were classified in group A and 12 in group B. In group B, the percentage of positive interface membrane histology was significantly higher than the percentage of positive pseudocapsule histology (83 vs 42%, P=0.04, Fisher's exact test). The results suggest that periprosthetic interface membrane is the best specimen for the histological diagnosis of prosthetic joint infection.

Alignment guided by computer navigation of the femoral component in hip resurfacing.

Surgical navigation systems are offered to provide more precise implantation of the femoral component in hip resurfacing (HR), allowing to reduce the risk of malpositioning and of femoral neck fracture and notching. We conducted a retrospective analysis of 30 HR divided into two cohorts and compared the results of a nonnavigated group (15 hips) with those of a navigated group (15 hips). The BrainLAB Computer Navigation System was used in all cases. No notching occurred in either group. The femoral component did not show better positioning in the navigated group, but more outlier cases were observed in the nonnavigated group (7, versus 3 in the navigated group). Although there are no long-term studies showing that surgical navigation increases the survival of HR, the avoidance of outlier values justifies its use, especially during the surgical learning curve, which is a difficult and lengthy one.

Hospital at home in elective total hip arthroplasty.

With the recent trend towards reducing hospital stay, it has become increasingly important to ensure that early patient discharge after total hip replacement is a safe practice. We evaluated complications and length of hospital stay associated with primary unilateral hip arthroplasty in 47 patients undergoing a new early discharge protocol consisting of at home based specialized care after hospital discharge. The mean length of stay (and standard deviation) in hospital was 4.59 ± 0.68. The mean length of stay of home-based hospitalization was 3.7 ± 1. The prevalence of postoperative complications was 12.8% and the readmission rate was 6.4%. We saw a reduction of hospital stay with no difference in outcomes in comparison with previous data. On the basis of our findings we recommend the use of the early discharge protocol following elective primary total hip replacement and ongoing evaluation of the process.

Plate osteosynthesis for severe olecranon fractures.

PURPOSE: To review outcomes of 10 patients who underwent plate osteosynthesis for severe olecranon fractures. METHODS: Records of 7 men and 3 women aged 33 to 73 years who underwent plate osteosynthesis for severe olecranon fractures were reviewed. All had some degree of soft-tissue injury; 6 presented with associated fractures. Seven patients were treated with a limited contact dynamic compression plate, and the remaining 3 received a locking compression plate. Patients were followed up for fracture healing, range of motion, nerve damage, heterotopic ossification, infection, hardware complaints, and the need of a secondary surgical procedure. The Mayo Elbow Performance Score (MEPS) was determined at the final follow-up. The patient-answered questionnaire (PAQ) portion of the Liverpool Elbow Score (LES) was evaluated 2 to 37 months later by telephone. RESULTS: All patients had bone union. None had nerve damage or heterotopic ossification. Patients 4, 6, and 8 with type-IIIB fractures developed deep infections and severe soft-tissue swelling; all had been treated with the limited contact dynamic compression plate. Four patients underwent plate removal owing to hardware complaints. One patient underwent a secondary procedure to restore complete range of elbow motion. The mean MEPS score was 84 (range, 35-100); 5 patients attained excellent scores, one good, 2 satisfactory, and 2 unsatisfactory. The mean PAQ portion of the LES score was 31 (range, 23-36). CONCLUSION: Plate osteosynthesis achieves satisfactory results for severe olecranon fractures. The deep infection rate is higher in patients with severe soft-tissue injury.

Cortical strut allograft as an adjunct to plate fixation for periprosthetic fractures of the femur.

The use of cortical strut allografts in the treatment of periprosthetic femoral fractures remain controversial. Complications such as infection and the potential transmission of disease remain concerns. A retrospective review at a tertiary-care hospital was completed of 21 patients who had sustained a periprosthetic femoral fracture and who were treated using a plate and a deep-frozen cortical strut allograft, between 1996 and 2007. The average age at the time of surgery was 80.3 years old and included 16 women and 5 men. Three patients were lost to follow-up and four died within a few weeks of discharge. The remaining 14 patients were evaluated clinically and radiographically with a mean follow-up of 3.2 years. Fracture union was observed in 13 patients, and integration of the graft occurred in 12 patients. One of the 14 patients developed a deep infection with Coagulase-Negative Staphylococcus, with a satisfactory outcome after surgical debridement and antibiotic treatment. There were no cases of fixation failure or plate rupture. At the final evaluation, the mean EQ-5D VAS score was 64 (ranging from 40-90 points) and the mean EQ-5D health state index adapted to Spanish value sets was 0.57. The mean Oxford Hip Score was 31.2. The results support the use of cortical allograft for these fractures to increase the likelihood of fracture healing and to improve the bone stock. We consider that cortical strut grafting is specially indicated for B1 and C fractures in which decreased bone density is present.

Timing of antibiotic prophylaxis for primary total knee arthroplasty performed during ischemia.

BACKGROUND: There is no clinical trial analyzing the best moment to infuse an antibiotic during knee arthroplasty performed during ischemia. We designed a single-center, randomized, double-blind, placebo-controlled trial to evaluate whether antibiotic therapy should be administered before tourniquet inflation or just before tourniquet deflation. MATERIAL AND METHODS: Patients who underwent a primary knee arthroplasty were randomized to receive (1) 1.5 g of cefuroxime 10-30 min before inflation of the tourniquet and placebo 10 min before release of the tourniquet (standard arm) or (2) placebo 10-30 min before inflation of the tourniquet and 1.5 g of cefuroxime 10 min before release of the tourniquet (experimental arm). In both arms, a postoperative dose of 1.5 g of cefuroxime was given 6 h after the surgical procedure. The main variables associated with the rate of deep-tissue infection after 3 and 12 months of follow-up were gathered. Continuous variables were compared using Student's t test, and categorical variables were compared using the chi(2) test or Fisher's exact test. RESULTS: From September 2004 through December 2005, a total of 908 patients were randomized, 442 and 466 of whom were allocated to the standard and experimental arms, respectively. There were no differences between treatment arms in terms of age, sex, comorbidity, American Society of Anaesthesiologists score, duration of surgery, need of blood transfusion, or fourth-day hematocrit. The rates of deep-tissue infection among the standard and experimental groups were 3.4% and 1.9%, respectively, at 3 months of follow-up (P = .21) and 3.6% and 2.6%, respectively, at 12 months of follow-up (P = .44). CONCLUSION: The administration of prophylactic antibiotics just before tourniquet release was not inferior to standard antibiotic prophylaxis.

Usefulness of histological analysis for predicting the presence of microorganisms at the time of reimplantation after hip resection arthroplasty for the treatment of infection.

BACKGROUND: Appropriate interpretation of a frozen section has a relatively high specificity and sensitivity for the diagnosis of infection when septic loosening of a prosthesis is suspected. However, its usefulness for predicting the presence of microorganisms at the time of reimplantation after hip resection arthroplasty for the treatment of infection is not well defined. The aim of the present study was to evaluate the usefulness of histological analysis in this situation. METHODS: From January 2002 to February 2006, a total of twenty-one patients underwent reimplantation after hip resection arthroplasty for the treatment of infection. Histological studies and cultures of specimens of periprosthetic tissue that had been obtained at the time of reimplantation were retrospectively reviewed. The results of culture were considered positive when the same microorganism was isolated in at least two samples. Two histological criteria were used to diagnose infection: (1) Criterion A (the Feldman criterion), defined as the presence of at least five neutrophils per high-power field (x400) in at least five separate microscopic fields and (2) Criterion B (the Athanasou criterion), defined as the presence of at least one neutrophil per high-power field (x400), on average, after examination of ten microscopic fields. The sensitivity, specificity, positive predictive value, and negative predictive value of each of these criteria were calculated with use of microbiological results as the gold standard for defining infection. RESULTS: Seven of the twenty-one patients had a positive result on culture, and the most common microorganism was coagulase-negative staphylococcus. The sensitivity, specificity, positive predictive value, and negative predictive value of frozen-section analysis were 28.5%, 100%, 100%, and 73.6%, respectively, according to the Feldman criterion and 71.4%, 64.2%, 50%, and 81.8%, respectively, according to the Athanasou criterion. The numbers of lymphocytes and plasma cells did not help in the diagnosis of infection. Fibrosis was more common in patients without an infection. CONCLUSIONS: The probability of infection is high when at least five neutrophils per high-power field are found in the periprosthetic tissue, but it is not possible to rule out infection when the number of neutrophils is less than five. LEVEL OF EVIDENCE: Diagnostic Level I.