The alpha defensin lateral flow test is effective in predicting eradication of periprosthetic joint infection after surgical debridement.

The primary aim of this study was to assess the utility of the alpha defensin lateral flow (ADLF) test for predicting the eradication of PJI after surgical debridement. The secondary aim was to describe the reliability of ADLF test in diagnosis of PJI intra- operatively. A prospective observational study was conducted in three independent orthopaedic centres. Twenty-two patients undergoing revision surgery (debridement, antibiotics and implant retention (DAIR), single or two-stage revision) for PJI were recruited, 13 female and 9 male with an average age of 64 years. Samples were collected intra-operatively at the start of the first surgical procedure and then at the completion of debridement or prior to reimplantation depending on the operation performed. These samples were tested using ADLF and then sent for microbiological analysis. The ADLF result was then compared to the corresponding culture result in order to determine the diagnostic predictive accuracy. The reliability of ADLF test to predict eradication of infection after debridement of PJI was excellent for specificity and positive predictive value (PPV) of which both where 100%, but had a poor sensitivity (14.3%) and negative predictive value (NPV) (62.5%). The reliability of ADLF test to predict PJI was poor with only a 50% sensitivity and specificity. The ADLF test has a high specificity and PPV for diagnosing eradication of infection after debridement. In contrast the ADLF testing appears to have poor diagnostic accuracy for PJI when used on intra-operative samples, prior to surgical intervention.

Diagnostic value of routine pre-operative investigations used in combination in the diagnosis of periprosthetic joint infection.

The primary aim of this study was to assess the diagnostic accuracy of joint aspiration culture, serum C-reactive protein (CRP) and serum erythrocyte sedimentation rate (ESR), individually, and in combination for the diagnosis of periprosthetic joint infection (PJI). A consecutive patient series with pre-operative inflammatory marker levels, an aspiration culture of either hip or knee arthroplasty and intra-operative culture samples from subsequent revision surgery was compiled. This retrospective patient cohort analysis included 128 aspiration. The data were analysed to compare pre-operative aspiration cultures, serum ESR and CRP levels to the chosen gold standard for PJI diagnosis of intra-operative culture samples. A diagnostic algorithm was created using the above tests combined with clinical suspicion index. The values that had the highest sensitivity and specificity of predicting PJI were >5 for CRP and >16 for ESR. CRP used individually had the highest sensitivity and negative predictive value (NPV) of any test (75.0% and 75.9%, respectively). ESR + aspirate had the highest specificity and positive predictive value (PPV), of 100% for both. Using all three tests together the specificity and PPV were higher than the test individual values (95.3% and 85.0% respectively). Based on subgroup analyses the combination of ESR or CRP plus joint aspiration has superior PPV compared to individual tests. ESR and CRP had the highest NPV when used in isolation. An algorithm has been developed to guide clinical diagnosis.

The Importance Of Multi-site Intra-operative Tissue Sampling In The Diagnosis Of Hip And Knee Periprosthetic Joint Infection - Results From A Single Centre Study.

Introduction: The primary aim of this study was to determine whether the tissue type and anatomical location of intra-operative samples influences the accuracy of culture in the diagnosis of periprosthetic joint infection (PJI). The secondary aim was to create a predictive model of PJI using other known patient variables. Methods: A retrospective cohort of 3460 intra-operative samples from 887 patients was identified. The data was then analysed to compare intra-operative culture results (positive or negative) to the chosen gold standard of clinical diagnosis made by the treating team (infected or non-infected prosthetic joint). The intra-operative samples were grouped according to their labelling at the time of collection. Results: No single tissue type or anatomical location had both high sensitivity and specificity. The highest specificity for an anatomical location was hip bursa with 100%, for tissue type it was synovium with 93%. Sensitivity was highest in the anatomical locations for hip capsule (68%) and in the tissue types for pus (83%). Data analysis was performed to create a model for PJI and identified pre-operative predictors of PJI (increased white cell count, knee joint and non-revision surgery) which when used in combination with intra-operative culture results increased the sensitivity. Conclusion: Sample type and anatomical location influenced the reliability of the diagnosis of PJI however, no single sample type had higher diagnostic accuracy than samples combined thereby highlighting the necessity of obtaining multiple intra-operative samples in the diagnosis of PJI. The variation in predictive values of tissue types as well as improvement in sensitivity when combined with patient factors indicates that types of intra-operative sampling and the overall diagnostic pathway should vary depending on the individual case.

Patterns of changes in femoral bone mineral density up to five years after hip resurfacing.

This is a prospective study of 26 patients (29 hips) on the patterns of change in the Bone Mineral Density (BMD) in various zones of the femoral neck and proximal femur five years after hip resurfacing. We have found that BMD continues to positively change up to five years after hip resurfacing. This was observed primarily in the trochanteric and superior neck regions. In both these regions BMD had decreased by up to 10% at six-weeks and three-months after surgery and then had recovered to preoperative level by one year. A regression analysis to assess the influence of age, gender, BMI, preoperative BMD, component size and orientation revealed that the best predictor of change in BMD at five years in the trochanteric area was acetabular component inclination.

Socio-economic impact of Birmingham hip resurfacing on patient employment after ten years.

Birmingham hip resurfacing is an attractive option for treatment of arthritis in young and active patients. The aim of this study was to assess the socio-economic impact of Birmingham hip resurfacing on their employment and work intensity at ten years. A cohort of 90 consecutive patients with 100 Birmingham hip resurfacing, performed by single surgeon, were reviewed prospectively. The mean age was 51 years at surgery. Prospective review was undertaken from surgery until the tenth post-operative year. Overall, 90% of patients were in the same employment following surgery. Two patients who were employed before surgery were unemployed. Three patients had to decrease their work intensity but were still employed. Three out of five disabled patients regained employment following surgery. Seventy-eight patients were able to continue their employment with no or minimal restriction. Birmingham hip resurfacing allows the majority of patients to continue their same employment at similar intensity ten years following surgery.

Judet's quadricepsplasty, surgical technique, and results in limb reconstruction.

Quadricepsplasty has been described by Thompson and Judet to improve flexion in severely ankylosed knees. Judet's technique has potential advantages because it is less damaging to the quadriceps mechanism and addresses the problem of external fixator pin site tethering on the lateral side of the thigh. The outcome of Judet's quadricepsplasty was assessed in 10 consecutive patients who were treated with external fixation either as a primary treatment (three patients) or as a secondary treatment for nonunion or malunion (seven patients) in a limb reconstruction unit. The patients were reviewed and examined at a minimal followup of 20 months. Their average prequadricepsplasty flexion of 33 degrees was improved to 105 degrees in the operating room and to 88 degrees on final review after an average followup of 24 months. According to Judet's criteria, there were one fair, seven good, and two excellent results. Two patients had postoperative complications, one hematoma and one infection. A minimal extension lag (10 degrees ) developed in one patient. Judet quadricepsplasty successfully increases flexion range with minimum impairment of quadriceps function. Familiarity with this technique might lower the surgeon's threshold for considering quadricepsplasty in patients with severe knee ankylosis after severe femoral fractures and in particular after a prolonged period of external fixation.

Outcome of complex fractures of the tibial plateau treated with a beam-loading ring fixation system.

Fine-wire external fixation is accepted as a minimally invasive technique, which can provide better outcomes than traditional open methods in the management of complex fractures of the tibial plateau. Available fixators vary in their biomechanical stability, and we believe that a stable beam-loading system is essential for consistently good outcomes. We assessed, prospectively, the clinical, radiological and general health status of 20 of 21 consecutive patients with complex fractures of the tibial plateau who had been treated using a standard protocol, with percutaneous screw fixation and a neutralisation concept with a fine wire beam-loading fixator allowing early weight-bearing. Bony union was achieved in all patients, with 85% having good or excellent results. Full weight-bearing started during the first six weeks in 60% of patients. The general health status assessment correlated well with the knee scores and reflected a satisfactory outcome.

Treatment of displaced bicondylar tibial plateau fractures (OTA-41C2&3) in patients older than 60 years of age.

OBJECTIVE: To investigate the outcome (clinical, radiographic, and general health status) of the surgical treatment of displaced bicondylar tibial plateau fractures (OTA-41C) in patients >60 years old. DESIGN: Prospective cohort study. SETTING: Limb reconstruction service, university teaching hospital. PATIENTS: Eleven consecutive patients >60 years old with a mean age of 72 years (range 60 to 90 years). The indications for surgery were displaced bicondylar tibial fractures, open fractures, and fractures with severe soft tissue injury. INTERVENTION: All patients were treated according to a standard protocol, which involved limited articular reconstruction and percutaneous intrafragmentary screw fixation, followed by neutralization with a stable beam-loading external fixator and early mobilization. MAIN OUTCOME MEASUREMENTS: The clinical outcome was assessed using Rasmussen's system and the Iowa knee score. For general health assessment, the anglicized SF-36 was used. Radiographic assessment was performed for redisplacement and angulation on digitized radiographs. RESULTS: After a mean follow-up of 38 months (range 18 to 51 months), bony union was achieved in all patients. Seven of 11 patients started full weight bearing 2 to 6 weeks postoperatively. According to Rasmussen's system, 9 of 11 (82%) scored satisfactory results. Radiographic redisplacement was found in three severely comminuted cases resulting in >/=10 degrees of valgus malunion. One patient received a corrective osteotomy while still in the fixator. Another needed TKA. Limited knee flexion was found in three patients with cross knee fixation. Superficial pin site infection occurred in five patients, but there were no cases of deep infections or septic arthritis. CONCLUSIONS: All-ring external fixation, as a beam-loading system applied in a neutralizing mode, is a safe, stable, and reliable technique for the treatment of displaced bicondylar tibial plateau fractures in elderly patients.