Aims The aim of this study was to determine the prevalence and characteristics of C-reactive protein (CRP)-negative prosthetic joint infection (PJI) and evaluate the influence of the type of infecting organism on the CRP level. Patients and Methods A retrospective analysis of all PJIs affecting the hip or knee that were diagnosed in our institution between March 2013 and December 2016 was performed. A total of 215 patients were included. Their mean age was 71 years (sd 11) and there were 118 women (55%). The median serum CRP levels were calculated for various species of organism and for patients with acute postoperative, acute haematogenous, and chronic infections. These were compared using the Kruskal–Wallis test, adjusting for multiple comparisons with Dunn’s test. The correlation between the number of positive cultures and serum CRP levels was estimated using Spearman correlation coefficient. Results Preoperative CRP levels were normal (< 10 mg/l) in 77 patients (35.8%) with positive cultures. Low-virulent organisms were isolated in 66 PJIs (85.7%) with normal CRP levels. When grouping organisms by species, patients with an infection caused by Propionibacterium spp., coagulase-negative staphylococci (CNS), and Enterococcus faecalis had significantly lower median serum CRP levels (5.4 mg/l, 12.2 mg/l, and 23.7 mg/l, respectively), compared with those with infections caused by Staphylococcus aureus and Streptococcus spp. (194 mg/l and 89.3 mg/l, respectively; p < 0.001). Those with a chronic PJI had statistically lower median serum CRP levels (10.6 mg/l) than those with acute postoperative and acute haematogenous infections (83.7 mg/l and 149.4 mg/l, respectively; p < 0.001). There was a significant correlation between the number of positive cultures and serum CRP levels (Spearman correlation coefficient, 0.456; p < 0.001). Conclusion The CRP level alone is not accurate as a screening tool for PJI and may yield high false-negative rates, especially if the causative organism has low virulence. Aspiration of the joint should be used for the diagnosis of PJI in patients with a chronic painful arthroplasty, irrespective of CRP level. Cite this article: Bone Joint J 2018;100-B:1482–86.

Background: Arthroscopic rotator cuff repair (RCR) with suture anchor–based fixation techniques has replaced former open and mini-open approaches. Nevertheless, long-term studies are scarce, and lack of knowledge exists about whether single-row (SR) or double-row (DR) methods are superior in clinical and anatomic results. Purpose: To analyze long-term results after arthroscopic RCR in patients with symptomatic rotator cuff tears and to compare functional and radiographic outcomes between SR and DR repair techniques at least 10 years after surgery. Study Design: Cohort study; Level of evidence, 3. Methods: Between 2005 and 2006, 40 patients with a symptomatic full-thickness rotator cuff tear (supraspinatus tendon tear with or without a tear of the infraspinatus tendon) underwent arthroscopic RCR with either an SR repair with a modified Mason-Allen suture–grasping technique (n = 20) or a DR repair with a suture bridge fixation technique (n = 20). All patients were enrolled in a long-term clinical evaluation, with the Constant score (CS) as the primary outcome measure. Furthermore, an ultrasound examination was performed to assess tendon integrity and conventional radiographs to evaluate secondary glenohumeral osteoarthritis. Results: A total of 27 patients, of whom 16 were treated with an SR repair and 11 with a DR repair, were followed up after a mean ± SD period of 12 ± 1 years (range, 11-14 years). Five patients underwent revision surgery on the affected shoulder during follow-up period, which led to 22 patients being included. The overall CS remained stable at final follow-up when compared with short-term follow-up (81 ± 8 vs 83 ± 19 points; P = .600). An increasing number of full-thickness retears were found: 6 of 22 (27%) at 2 years and 9 of 20 (45%) at 12 years after surgery. While repair failure negatively affected clinical results as shown by the CS ( P < .05), no significant difference was found between the fixation techniques ( P = .456). In general, progressive osteoarthritic changes were observed, with tendon integrity as a key determinant. Conclusion: Arthroscopic RCR with either an SR or a DR fixation technique provided good clinical long-term results. Repair failure was high, with negative effects on clinical results and the progression of secondary glenohumeral osteoarthritis. While DR repair slightly enhanced tendon integrity at long-term follow-up, no clinical superiority to SR repair was found.

BackgroundTwo-stage exchange arthroplasty is still the preferred treatment choice for chronic PJI. However, the results remain unpredictable. We analyzed the treatment success of patients with an infected hip prosthesis, who were treated according to a standardized algorithm with a multidisciplinary team approach and evaluated with a strict definition of failure.MethodsIn this single-center prospective cohort study, all hip PJI episodes from March 2013 to May 2015 were included. Treatment failure was assessed according to the Delphi-based consensus definition. The Kaplan-Meier survival method was used to estimate the probability of infection-free survival. Patients were dichotomized into two groups depending on the number of previous septic revisions, duration of prosthesis-free interval, positive culture with difficult-to-treat microorganisms, microbiology at explantation, and microbiology at reimplantation.ResultsEighty-four patients with hip PJI were the subject of this study. The most common isolated microorganisms were coagulase-negative staphylococci (CNS) followed by Staphylococcus aureus and Propionibacterium. Almost half of the study cohort (46%) had at least one previous septic revision before admission. The Kaplan-Meier estimated infection-free survival after 3 years was 89.3% (95% CI, 80% to 94%) with 30 patients at risk. The mean follow-up was 33.1 months (range, 24–48 months) with successful treatment of PJI. There were no statistical differences in infect eradication rate among the dichotomized groups.ConclusionsHigh infect eradication rates were achieved in a challenging cohort using a standardized two-stage exchange supported by a multidisciplinary approach.