Treatment outcomes of patients with Cutibacterium acnes-positive cultures during total joint replacement revision surgery: a minimum 2-year follow-up.

INTRODUCTION: Periprosthetic joint infection (PJI) is a devastating complication following total joint replacement (TJR). Cutibacterium acnes (C. acnes) is a low virulent skin commensal, commonly found during TJR revision surgery for "aseptic" causes. The purpose of the present study was to report the treatment outcomes of patients with C. acnes contamination or infection in the presence of a TJR treated with a revision surgery ± implant exchange ± prolonged (≥ 8 weeks) postoperative antibiotics. METHODS: Medical records of patients with at least one positive C. acnes culture in intraoperative tissue samples or sonication fluid from a TJR revision surgery between January 2005 and December 2014 were retrospectively evaluated. The primary endpoint was infection eradication according to Delphi criteria. The diagnostic accuracy of preoperative TJR aspiration regarding the diagnosis of C. acnes PJI was also investigated. RESULTS: A total of 52 TJR (28 shoulders, 17 hips, 7 knees) in 52 patients (35 males, 17 females) with an average age of 63 ± 11 (33-86) years were included. At an average follow-up of 67 ± 33 (24-127) months, the infection eradication of C. acnes PJI was 97% regardless of the surgical treatment or administration of prolonged postoperative antibiotics. The incidence of unsuspected C. acnes PJI was 28.8%. The sensitivity and specificity of preoperative joint aspiration in detecting C. acnes PJI were 59% and 88%, whereas the PPV and NNV were 83% and 67%, respectively. CONCLUSION: Infection eradication of C. acnes PJI was very high at a minimum follow-up of 24 months, suggesting that C. acnes PJI could be adequately treated with a combination of revision surgery and prolonged postoperative antibiotics. The preoperative diagnosis of C. acnes PJI might be challenging with more than one-quarter of patients presenting without suspicion of C. acnes PJI. The appropriate treatment of patients with a single positive culture remains still unclear. A negative TJR aspiration should not rule out a C. acnes PJI, especially in the presence of clinical correlates of infection. LEVEL OF EVIDENCE: Retrospective case-control study, Level III. IRB APPROVAL: Kantonale Ethikkommission Zürich, BASEC Nr.:2017-00567.

Synovial C-reactive protein features high negative predictive value but is not useful as a single diagnostic parameter in suspected periprosthetic joint infection (PJI).

OBJECTIVES: Synovial fluid C-reactive protein (syCRP) has been recently described as a new biomarker in preoperative diagnostics to identify periprosthetic joint infections (PJI). The aim of this study was to evaluate syCRP in a large cohort of patients with suspected PJI and to calculate the optimal cut-off to diagnose PJI. METHODS: Between September 2015 and June 2017, we prospectively included patients with suspected PJI, in which syCRP was additionally measured along with routine preoperative diagnostic serum and synovial biomarkers. We analysed the sensitivity and specificity of syCRP using receiver operating characteristic curves. RESULTS: We included 192 cases (hip n = 80, knee n = 91, shoulder n = 21) with a final diagnosis of PJI in 26 cases (14.0%). Combined for all joints, the syCRP values were significantly higher in the PJI group than in the no PJI group (median: 13.8 vs. 0 mg/l; p < 0.001). The optimal cut-off (Youden Index: 0.71) for the PJI diagnosis combined for all joints was at a syCRP value of 2.9 mg/l with a sensitivity of 88%, a specificity of 82%, and a negative predictive value of 98%. CONCLUSIONS: SyCRP features high negative predictive value but is not useful as a single diagnostic parameter in suspected periprosthetic joint infection (PJI).

Inflammatory disorders mimicking periprosthetic joint infections may result in false-positive α-defensin.

OBJECTIVES: The antimicrobial peptide α-defensin has recently been introduced as a potential 'single' biomarker with a high sensitivity and specificity for the preoperative diagnosis of periprosthetic joint infections (PJIs). However, most studies assessed the benefits of the test with exclusion of patients with rheumatic diseases. We aimed to evaluate the α-defensin test in a cohort study without exclusion of people with inflammatory diseases. METHODS: Between June 2016 and June 2017, we prospectively included cases with a suspected PJI and an available lateral flow test α-defensin (Synovasure®) in synovial fluid. We compared the test result to the diagnostic criteria for PJIs published by an International Consensus Group in 2013. RESULTS: We included 109 cases (49 hips, 60 knees) in which preoperative α-defensin tests had been performed. Among these, 20 PJIs (16 hips, four knees) were diagnosed. Preoperative α-defensin tests were positive in 25 cases (22.9%) with a test sensitivity and specificity of 90% and 92.1% (95% CI 68.3%-98.8% and 84.5%-96.8%, respectively), and a high negative predictive value of 97.6% (95% CI 91.7%-99.4%). We interpreted seven α-defensin tests as false positive, mainly in cases with inflammatory rheumatic diseases, including crystal deposition diseases. CONCLUSIONS: A negative synovial α-defensin test can reliably rule out a PJI. However, the test can be false positive in conjunction with an underlying non-infectious inflammatory disease. We therefore propose to use the α-defensin test only in combination with Musculoskeletal Infection Society criteria and assessment for crystals in synovial aspirates.

[Indications for joint replacement : Total hip arthroplasty]. / Indikationen zum Gelenkersatz : Hüfttotalendoprothese.

Total hip arthroplasty (THA) is a very successful and effective orthopedic operation with very good immediate as well as long-term results to alleviate pain and improve health-related quality of life. A THA is indicated in end-stage hip osteoarthritis with a high degree of persistent suffering when conservative treatment has failed and in patients who wish a THA. This statement is generally valid for patients where the medical history, clinical examination and radiographic findings are conclusive, the pressure of suffering and the expectations are realistic. The timing of THA is based on the patient's discomfort. The treatment of these patients should include an interdisciplinary approach and the main goal is to improve the quality of life. Patients will learn to have reasonable expectations and should be well informed about the risks and benefits of THA. Realistic patient expectations seem to be a predictive factor for a good subjective outcome after THA.

Femoroacetabular impingement inducing non-union of a femoral neck fracture: a case report.

INTRODUCTION: We describe a case in which femoroacetabular impingement (FAI) was identified as the cause of non-union of a femoral neck fracture and the subsequent treatment strategy. MATERIALS AND METHODS: Retrospective review of a 35-year-old patient, without any risk factors for non-union, who sustained a femoral neck fracture. Pre-existing FAI was identified as the cause for the non-union of the femoral neck fracture, with successful treatment of the non-union according to established arthroscopic treatment of the hip. RESULTS: After treatment of the FAI, the non-union healed uneventfully within 3 months. CONCLUSIONS: FAI may be a less common but potential cause of delayed union or non-union in the setting of femoral neck fracture in the young.

Cost analysis of fresh-frozen femoral head allografts: is it worthwhile to run a bone bank?

To assess the sustainability of our institutional bone bank, we calculated the final product cost of fresh-frozen femoral head allografts and compared these costs with the use of commercial alternatives. Between 2007 and 2010 all quantifiable costs associated with allograft donor screening, harvesting, storage, and administration of femoral head allografts retrieved from patients undergoing elective hip replacement were analysed. From 290 femoral head allografts harvested and stored as full (complete) head specimens or as two halves, 101 had to be withdrawn. In total, 104 full and 75 half heads were implanted in 152 recipients. The calculated final product costs were €1367 per full head. Compared with the use of commercially available processed allografts, a saving of at least €43 119 was realised over four-years (€10 780 per year) resulting in a cost-effective intervention at our institution. Assuming a price of between €1672 and €2149 per commercially purchased allograft, breakeven analysis revealed that implanting between 34 and 63 allografts per year equated to the total cost of bone banking.

The anterior center edge angle in Lequesne's false profile view: interrater correlation, dependence on pelvic tilt and correlation to anterior acetabular coverage in the sagital plane. A cadaver study.

INTRODUCTION: Lequesne's vertical-center-anterior margin (VCA) angle measured on the false profile view of the pelvis aims at quantifying the anterior acetabular coverage of the femoral head. The anterior delimitation of the acetabular roof is often defined on the false profile view but there are no data on its interrater reliability. Additionally, it is not known how pelvic tilt may influence this angle. Finally, the plane in which this angle is measured lies at an angle of 65 degrees to the sagittal plane and we wondered if this angle would be transposable to the anterior acetabular coverage measured in the sagittal plane. METHODS: Eight hips from four cadaver pelvises were investigated by means of a total of 72 false profile views, each taken in defined pelvic inclinations at 5 degrees increments ranging from -20 degrees to +20 degrees , and the VCA angle measured by three independent raters. A computed tomography (CT) of each hip was performed in a neutral pelvic tilt position and a sagittal 2D reconstruction calculated in order to measure anterior coverage in the sagittal plane. The interrater reliability of the VCA angles was assessed using the intra-class correlation coefficient (ICC). The dependence of the VCA angle on pelvic tilt was assessed by regression analysis. The Correlation between the VCA angle and anterior coverage in the sagittal plane of the CT was analyzed using a simple linear regression model. RESULTS: The interrater reliability for measurements of the VCA angle was almost perfect (ICC:0.97). Regression analysis showed that each degree of pelvic tilt was accompanied by a change of the VCA angle by a value of 0.63 degrees (P < 0.001). A low correlation between the VCA angle measured in the false profile view and the anterior coverage in the sagittal plane was statistically not significant (r = 0.667, P = 0.06). CONCLUSIONS: Lequesne's VCA angle has an excellent interrater reliability and represents a reliable measure of acetabular dysplasia for comparisons with published data. Lequesne's VCA angle is influenced by pelvic tilt in a linear manner. Performing the false profile view in a standing position may reduce the clinical relevance of this dependency on pelvic tilt. The correlation of Lequesne's VCA angle to anterior acetabular coverage in the sagittal plane is low and therefore unsuitable to be transposed into the sagittal plane.

Clinical and structural outcomes of nonoperative management of massive rotator cuff tears.

BACKGROUND: The natural history of massive rotator cuff tears is not well known. The purpose of this study was to determine the clinical and structural mid-term outcomes in a series of nonoperatively managed massive rotator cuff tears. METHODS: Nineteen consecutive patients (twelve men and seven women; average age, sixty-four years) with a massive rotator cuff tear, documented by magnetic resonance imaging, were identified retrospectively. There were six complete tears of two rotator cuff tendons and thirteen complete tears of three rotator cuff tendons. All patients were managed exclusively with nonoperative means. Nonoperative management was chosen when a patient had low functional demands and relatively few symptoms and/or if he or she refused to have surgery. For the purpose of this study, patients were examined clinically and with standard radiographs and magnetic resonance imaging. RESULTS: After a mean duration of follow-up of forty-eight months, the mean relative Constant score was 83% and the mean subjective shoulder value was 68%. The score for pain averaged 11.5 points on a 0 to 15-point visual analogue scale in which 15 points represented no pain. The active range of motion did not change over time. Forward flexion and abduction averaged 136 degrees; external rotation, 39 degrees; and internal rotation, 66 degrees. Glenohumeral osteoarthritis progressed (p = 0.014), the acromiohumeral distance decreased (p = 0.005), the size of the tendon tear increased (p = 0.003), and fatty infiltration increased by approximately one stage in all three muscles (p = 0.001). Patients with a three-tendon tear showed more progression of osteoarthritis (p = 0.01) than did patients with a two-tendon tear. Four of the eight rotator cuff tears that were graded as reparable at the time of the diagnosis became irreparable at the time of final follow-up. CONCLUSIONS: Patients with a nonoperatively managed, moderately symptomatic massive rotator cuff tear can maintain satisfactory shoulder function for at least four years despite significant progression of degenerative structural joint changes. There is a risk of a reparable tear progressing to an irreparable tear within four years.