Purpose

Many studies have found associations between laboratory biomarkers and periprosthetic joint infection (PJI), but it remains unclear whether these biomarkers are clinically useful in ruling out PJI. This meta-analysis compared the performance of interleukin-6 (IL-6) versus procalcitonin (PCT) for the diagnosis of PJI.

The purpose of this prospective randomized study was to compare the visible, hidden, total blood loss and postoperative haemodynamic change of subcutaneous and intra-articular indwelling closed suction drainage method after total knee arthroplasty (TKA). Patients with primary osteoarthritis, who underwent unilateral TKA were enrolled; Group A with subcutaneous (n=78) and group B with intra-articular (n=79) indwelling closed suction drainage method. Total blood loss, visible blood loss, internal blood loss, postop (day 1), 5^th, 10^th day hemoglobin, hematocrit levels were compared. Allogenic blood transfusion rate and complications related to soft tissue hematoma formation were additionally compared. Subcutaneous indwelling closed suction drainage method reduced both the visible blood loss and total blood loss (hemovac drainage + internal blood loss) thus decreasing the rate of allogenic transfusion. Although the minor complications such as the incidence of bullae formation and the ecchymosis were higher in the subcutaneous indwelling group, the functional outcome at postoperative 2 year did not demonstrate difference from intra-articular drainage group.

To investigate the effectiveness of avulsion fracture of tibial insertion of posterior cruciate ligament using the safe postero-medial approach through analyzing the clinical and radiographic outcomes. We treated 14 cases of acute PCL tibial avulsion fracture with “safe postero-medial approach”. The PCL and avulsion bony fragment was fixed with 1 cannuated screw and washer. The patients were assessed clinically and radiographically at 3 months, 6 months, and 12 months. Clinical examination for each visit included assessment of the knee range of motion, using goniometer and the posterior drawer test. The patients were evaluated according to the Lysholm and Tegner rating scales. Patients were followed-up for 12 to 16 months. X-ray showed that satisfactory reducdtion and bony healing was achieved in all cases. There was no neurovascular complication. All patients had negative posterior drawer tests. Excellent outcomes were reported by all patients with the Lysholm score system. And there was no signicant difference between the Tegner scores before injury and last follow-up. Surgical treatment of acute tibial avulsion fracture of the PCL with this approach can restore the stability and fuction of the joint safely in most patients without neurovascular complication. Therefore “safe postero-medial approach” may be suitable for the treatment of isolated tibial avulsion fracture of the PCL.

It has been suggested that metal ion levels are indicative of in vivo bearing performance of metal-on-metal hip replacements. A cobalt or Chromium level of 7μg/L or higher is proposed to be indicative of a bearing malfunction and the need for clinical intervention. Component design, size, acetabular orientation, patient gender and activity level have been suggested as factors leading to accelerated wear and elevated metal ions. The contact patch to rim (CPR) distance is a calculation that describes the distance from the point where a theoretical joint reaction force intersects the cup to the acetabular rim for a patient in standing position, dependent on the coverage, size, and orientation of the acetabular component. It has been suggested that CPR distance determines the hip joint susceptibility to edge loading, and the risk for increased wear and high ion levels (Langton et al JBJS Br 91: 2009). This study examined the effects of patient activity, gender, and CPR distance on serum metal ion concentrations in a series of patients treated with one type of metal on metal hip resurfacing arthroplasty (MMHRA) performed by one surgeon.

182 patients (73 females and 109 males)with a unilateral Conserve Plus (WMT, TN USA) MMHRA and had who had provided blood for metal ion analysis data from December 2000 to June 2011 were retrospectively studied. Only measurements made more than 12 months after surgery were included in order to exclude hips that had yet to reach steady-state wear. For patients with multiple draws, the most recent qualifying draw was used. Activity level was assessed by the UCLA activity score. The mean age was 51.5 years (20.0 to 77.5 years). The mean follow-up time for the last blood draw was 70 months (range, 12 to 165). Serum cobalt (CoS) and chromium (CrS) levels were analyzed using inductively coupled plasma mass spectrometry in a specialized trace element lab. Using acetabular abduction and anteversion measured by EBRA, component size, and reported coverage angle of the acetabular component, the CPR distance was calculated as previously described. Multiple logistic regression was performed to identify significant relationships between high metal ion levels (7 μg/L or greater) and gender, activity and CPR distance.

The median CoS level for the entire cohort was 1.13 μg/L (range, 0.15 to 175.30), and the median CrS level was 1.49 μg/L (range, 0.06 to 88.70). The average CPR distance was 13.8 mm (range, 3.2 to 22.1). There was a significant association between low CPR values and CoS and CrS. There was a 37-fold increase in the risk of CoS >7μg/L (p=0.005) and 11-fold increase in the risk of CrS > 7μg/L (p=0.003) when CPR distance was 10 mm or less. No associations were shown for gender and UCLA activity scores.

CPR distance was found to be a reliable predictor of ion levels > 7μg/L and appears to be a useful indicator to evaluate the multi-factorial process of edge-loading and wear. Patients with a low CPR distance should be monitored for increased metal ion levels.