Aim. Low-grade infections cannot be easily distinguished from aseptic complications frequently leading to false negative diagnoses and late onset of anti-bacterial therapy. Therefore, there is a great need to establish biomarkers for early detection of low-grade infections. Method. In this study, we focused on the investigation of anti-α-defensin, anti-C3, anti-C5 and anti-C9 as potential biomarkers for infection in a cohort of hip and knee septic revision cases, taking patient characteristics and comorbidities into account. Here we included 78 patients with septic (35) and aseptic (43) (woman:37, men:42, age 50 – 93 years) revision surgeries of hip and knee. CRP serum levels and leucocyte blood values were evaluated. Patient characteristics, including age, number of prior revision surgeries and comorbidities were recorded. Periprosthetic tissue was stained histologically with Hematoxylin/Eosin and immunohistologically with different antibodies. Results. The CRP values were significantly increased in the septic cohort, but no changes were observed in leucocyte count. Interestingly, we found a strong increase in the terminal complement system component C9 (septic: 0.1% ± 0.2% aseptic: 0.01% ± 0.05%, p= 0.0004) in the septic periprosthetic tissue. The predictive value of α-defensin staining was not statistically significant (septic: 0.5% ± 0.7% aseptic: 0.1% ± 0.6%, p= 0.09). Analyzing the synovial fluid of aseptic and septic patients, the presence of C9 in the septic group (1.8 ± 0.4) was not significantly higher compared to the aseptic (1.9 ± 0.7) group. The next step was to investigate the specificity C9 detection using different joint related diseases such as chondrocalcinosis (CC), rheumatoid arthritis (RA) and metallosis. The median of C9 staining in the CC group (0 ± 0.0001) was significant lower than the infection group. Similar results have been observed in RA (0.0003 ± 0.2) and the metallosis group (0.0002 ± 0.01). Conclusions. We found a strong predictive value of anti-C9 staining for tissue infection, suggesting that C9 deposition could be a novel biomarker for the identification of periprosthetic joint infections using tissue biopsies

INTRODUCTION. The diagnosis of peri-prosthetic infection may be difficult. But this diagnosis can guide antibiotic prophylaxis and implementation of intraoperative bacteriological samples. The hypothesis of this study was that a composite score using clinical, radiological and biological data could be used for positive and negative diagnostic of infection before reoperation on prosthetic hip or knee. MATERIAL. 200 reoperations on hip and knee arthroplasty for any cause were analyzed retrospectively. 100 cases concerned infected cases, while the diagnosis of infection was excluded in the other 100 cases. METHODS. Different criteria were collected: previous surgery of the operated joint, clinical, biological and radiological signs. Univariate analysis investigated the discriminating factors of infected and non infected cases. Multivariate analysis integrated concomitantly these factors. A composite score was defined, and its diagnostic efficacy was assessed by the percentage of the total variance explained by the score, by the percentage of correctly classified cases and by the sensitivity and specificity. RESULTS. The univariate and multivariate analyzes have isolated the following significant factors: body mass index, diabetes, prosthetic mechanical complication, fever, existence of a wound defect. The composite score so defined allows separating the infected and non infected patients accurately in 78% of cases, with a sensitivity of 57% and a specificity of 93%. DISCUSSION. The composite score defined predicts infection or no infection in the prosthetic joint before reoperation with good efficiency. This score could be a significant help to define the medical and surgical strategy in a prosthetic hip or knee reoperation for whatever reason. CONCLUSION. A prospective study is needed to confirm definitively the contribution of this score

Although cemented fixation provides excellent results in primary total hip replacement (THR), particularly in patients older than 75 years, uncemented implants are most commonly used nowadays. We compare the rate of complications, clinical and radiological results of three different designs over 75-years-old patients. Materials and Methods. 433 hips implanted in patients over 75 years old were identified from our Local Joint Registry. Group A consisted of 139 tapered cemented hips, group B of 140 tapered grit-blasted uncemented hips and group C of 154 tapered porous-coated uncemented hips. A 28 mm femoral head size on polyethylene was used in all cases. The mean age was greater in group A and the physical activity level according to Devane was lower in this group (p<0.001 for both variables). Primary osteoarthritis was the most frequent diagnoses in all groups. The radiological acetabular shape was similar according to Dorr, however, an osteopenic-cylindrical femur was most frequently observed in group A (p<0.001). The pre- and post-operative clinical results were evaluated according to the Merle-D'Aubigne and Postel scale. Radiological cup position was assessed, including hip rotation centre distance according to Ranawat and cup anteversion according to Widmer. We also evaluated the lever arm and height of the greater trochanter distances and the stem position. Kaplan-Meier analysis was done for revision for any cause and loosening. Results. The hip rotation centre distance was greater and the height of the greater trochanter was lower in group B (p=0.003, p<0.001, respectively). The lever arm distance was lower in group C (p<0.001). A varus stem position was more frequently observed in group B (p<0.001). There were no intra- or post-operative fractures in group A, although there were five intra-operative fractures in the other groups plus two post-operative fractures in group B and four in group C. The rate of dislocation was similar among groups and was the most frequent cause for revision surgery (8 hips for the whole series). The mean post-operative clinical score improved in all groups. The overall survival rate for revision for any cause at 120 months was 88.4% (95% CI 78.8–98), being 97.8% (95% CI 95.2–100) for group A, 81.8% (95% CI 64.8–98.8) for group B and 95.3% (95% CI 91.1–99.6) for group C (log Rank: 0.416). Five hips were revised for loosening. The overall survival rate for loosening at 120 months was 91.9% (95% CI 81.7–100), being 99.2%(95% CI 97.6–100) for group A, 85.5 (95% CI 69.9 −100) for group B and 100% for group C (Log Rank 0.093). Conclusions. Despite a more osteopenic bone in the cemented group, the rate of peri-prosthetic fractures was higher after uncemented THR in patients older than 75 years. Although the overall outcome is good with both types of fixation, the post-operative reconstruction of the hip, which might be more reliable after cemented fixation, may affect the rate of complications in this population

Introduction:. The outcome of previous cemented total hip arthroplasty has been reported to be inferior in renal transplant patients because of poor bone stock resulting from long-term steroid use. Moreover, as renal transplant patients remain on immunosuppressant therapy for life, higher levels of overall morbidity must be considered. We evaluated the mid-term results of cementless total hip arthroplasty in renal transplant recipients with osteonecrosis of the femoral head, and compared those with age and sex matched osteonecrosis patients that had not undergone organ transplantation or been treated with long-term steroid. Materials & Methods:. Between October 1997 and October 2008, 45 consecutive primary cementless total hip arthroplasties were performed in 30 patients with advanced osteonecrosis of the femoral head after renal transplantation. There were 18 males (27 hips) and 12 females (18 hips) of overall mean age 44 years (22 to 68). The clinical and radiographic results of cementless total hip arthroplasty in these 45 hips were compared with those of 96 sex and age-matched osteonecrotic hips of 72 patients that had not undergone organ transplantation or long-term steroid use. Patients were evaluated at surgery and at a mean of 7.2 years (range, 2–13 years) postoperatively. Results:. The mean Harris hip score of patients improved from 48 points preoperatively to 94 points at last follow-up (p < 0.05). Three hips in patient group had massive osteolysis with polyethylene wear requiring revision surgery. One hip in the patient group underwent revision surgery because of recurrent dislocation at 11 years postoperatively. No intergroup differences in overall rates of complications or revisions were observed. However, patients had a significantly higher rate of ectopic ossification. Conclusion:. Despite diffuse osteopenia and chronic immunosuppression in renal transplant patients with osteonecrotic hips, contemporary cementless total hip arthroplasty showed durable implant fixation to bone and did not increase complications

Background. Ultrasound and MRI are recommended tools in evaluating postoperative pain in metal-on-metal hip (MoM) arthroplasty. Aim. To retrospectively compare MRI and ultrasound results of the hip with histopathology results in failed (MoM) hip arthroplasty. Methods. 25 hips (16 patients) who underwent revision hip surgery for painful (MoM) hip replacement/resurfacing were included in this study (March 2011 to May 2012). Average age 50.4 yrs (37–69y). Blood test for cobalt and chromium levels, ultrasound and MRI were done prior to revision surgery. 23 hips had ultrasound scan. 21 of these hips also had MRI scan prior to surgery. Scans were done at an average of 50 months from primary metal-on-metal surgery. All the ultrasound & MRI were done and reported by a single musculo-skeletal radiologist. During surgery multiple tissue samples were taken from acetabulum, capsule as well as tissue surrounding the femoral neck and sent for histopathology. 21 hip histopathology results were positive for metalosis. 2 hip histopathology results were negative for metalosis. Metalosis as defined by our histopathologist as that which is showing the presence of sheets of macrophages with dark brown pigmentation in their cytoplasm under polarized light. Results. Ultrasound examination was positive for fluid collection in 18 (78.2%). MRI was positive in 16 (76.1%). 4 patients (19%) had negative ultrasound and MRI results but were revised due to pain and were found to have histopathology positive metalosis. One patient had ultrasound positive for fluid collection with negative MRI. One patient was MRI positive for fluid but normal ultrasound findings. Conclusion. Although ultrasound and MRI are useful in screening of MoM patients still there are a significant percentage of hips, which failed with negative radiology findings