Assessment of antimicrobial mismatches in empirical treatment in early PJI after aseptic revision arthroplasty.

Background: In early periprosthetic joint infection (PJI), 'debridement, antibiotics and implant retention' (DAIR) is a widely accepted form of treatment. Empirical antimicrobial treatment is started while culture results of tissue samples taken during debridement are pending. Objectives: In this retrospective study we assessed the antimicrobial mismatch rate between empirical treatment and the susceptibility of the causative microorganisms of PJI after aseptic revision arthroplasty. We analysed risk factors for antimicrobial mismatches and the impact of mismatches on the outcome of PJI treatment. Results: A total of 119 patients were included in the analysis. In 72% (86/119) of the cases there was an antimicrobial mismatch in empirical treatment. Most of the antimicrobial mismatches were caused by multidrug-resistant (MDR) Staphylococcus spp. (77%, 66/86). In multivariable analysis, polymicrobial PJI was significantly associated with antimicrobial mismatch (OR: 6.89; 95% CI: 2.38-19.53; P < 0.001), and antimicrobial mismatch was significantly associated with reduced success rate of PJI treatment (OR: 0.20; 95% CI: 0.05 ±â€…0.82; P = 0.026). There was no difference in successful outcome between PJI caused by Gram-negative bacilli (61%) and Gram-positive bacteria (69%, P = 0.516). Conclusions: Mismatching empirical antimicrobial treatment after DAIR following aseptic revision arthroplasty was significantly associated with failure of PJI treatment. Polymicrobial PJI is a risk factor for antimicrobial mismatch of the empirical treatment of PJI. Antimicrobial mismatch and delay in targeted treatment should be integrated in the approach to optimize antibiotic treatment to improve clinical outcomes, while minimizing unintended side effects of antimicrobial use (antimicrobial stewardship).

The unsuspected prosthetic joint infection : incidence and consequences of positive intra-operative cultures in presumed aseptic knee and hip revisions.

AIMS: Positive cultures are not uncommon in cases of revision total knee and hip arthroplasty (TKA and THA) for presumed aseptic causes. The purpose of this study was to assess the incidence of positive intra-operative cultures in presumed aseptic revision of TKA and THA, and to determine whether the presence of intra-operative positive cultures results in inferior survival in such cases. PATIENTS AND METHODS: A retrospective cohort study was assembled with 679 patients undergoing revision knee (340 cases) or hip arthroplasty (339 cases) for presumed aseptic causes. For all patients three or more separate intra-operative cultures were obtained. Patients were diagnosed with a previously unsuspected prosthetic joint infection (PJI) if two or more cultures were positive with the same organism. Records were reviewed for demographic details, pre-operative laboratory results and culture results. The primary outcome measure was infection-free implant survival at two years. RESULTS: The incidence of unsuspected PJI was 27 out of 340 (7.9%) in TKA and 41 out of 339 (12.1%) in THA. Following revision TKA, the rate of infection-free implant survival in patients with an unsuspected PJI was 88% (95% confidence intervals (CI) 60 to 97) at two years compared with 98% (95% CI 94 to 99) in patients without PJI (p = 0.001). After THA, the rate of survival was similar in those with unsuspected PJI (92% (95% CI 73 to 98) at two years) and those without (94% (95% CI 89 to 97), p = 0.31). CONCLUSION: Following revision of TKA and THA for aseptic diagnoses, around 10% of cases were found to have positive cultures. In the knee, such cases had inferior infection-free survival at two years compared with those with negative cultures; there was no difference between the groups following THA. Cite this article: Bone Joint J 2017;99-B:1482-9.

Moderate clinical improvement after revision arthroplasty of the severely stiff knee.

PURPOSE: Revision of the severe stiff total knee arthroplasty (TKA) is challenging, and clinical outcome is inferior to other indications for revision. The purpose of the present study was to determine clinical outcome of TKA revision in patients with severe stiffness (range of motion (ROM) ≤ 70°) and evaluate a possible influence of accompanying findings, such as component malposition, aseptic loosening or instability. METHODS: A prospective cohort of 40 patients with a preoperative ROM ≤ 70° and a minimum of 2-year follow-up after total system revision (Genesis or Legion stemmed condylar implant) was evaluated. ROM, Knee Society Scoring System (KSS) and visual analogue scale (VAS) pain scores were obtained preoperatively and at 2 years. Patient satisfaction and complication rate were assessed. Component malposition was most frequently reported as accompanying finding (n = 27). Comparisons between pre- and postoperative outcome (p < 0.05) and between different subgroups (component malposition, aseptic loosening, and instability) based on accompanying findings were made (no statistical comparison). RESULTS: ROM, KSS and VAS pain scores improved significantly (p < 0.001): median ROM at two years 85° (range 10-125) and median gain 25° (range -10 to +85). Median VAS satisfaction was 53.5 points (range 15-98). Seventeen patients reported at least one complication, including one re-revision. Six patients underwent manipulation under anaesthesia, and five were referred to the pain clinic. No clear differences between subgroups were observed. CONCLUSIONS: TKA revision in patients with severe stiffness resulted in a moderate but significant improved clinical outcome after 2 years. Accompanying abnormalities such as component malposition, aseptic loosening or instability did not influence clinical outcome. Realistic patient counselling on the moderate outcome and possible remaining limitations in daily life might help to improve patient satisfaction. LEVEL OF EVIDENCE: Therapeutic studies-case series with no comparison group, Level IV.

Debridement, antibiotics and implant retention in early periprosthetic joint infection after primary total hip arthroplasty : 88 percent survival after two years follow-up.

Treatment protocols and results of debridement, antibiotics, irrigation and retention of the prosthesis (DAIR) for early prosthetic joint infection (PJI) vary in literature. The purpose of this study was to analyze the results of DAIR with a multidisciplinary designed customized antibiotic protocol for early PJI after primary total hip replacement (THR). We retrospectively analyzed all patients with an early PJI between 2008 and 2012. When an infection was suspected, debridement of the prosthesis, and -collection of intraoperative cultures, was performed. -Patients were multidisciplinary discussed and treated with an appropriate antibiotic scheme for 12 weeks. Primary outcome was retention of the prosthesis after at least two years follow-up and without any signs of infection. We indentified 25 patients with early PJI. At a median follow-up time of 3.1 years (range 2.1-5.5 years), 88% had retention of the prosthesis and no signs of infection. This study suggests that DAIR with a multidisciplinary approach and an aimed antibiotic treatment for early PJI after THR is a reasonable treatment -option with 88% implant retention after two years follow-up.

Dual mobility acetabular component in revision total hip arthroplasty for persistent dislocation: no dislocations in 50 hips after 1-5 years.

BACKGROUND: A dual mobility cup has the theoretic potential to improve stability in primary total hip arthroplasty (THA) and mid-term cohort results are favorable. We hypothesized that use of a new-generation dual mobility cup in revision arthroplasty prevents dislocation in patients with a history of recurrent dislocation of the THA. MATERIALS AND METHODS: We performed a retrospective cohort study of patients receiving an isolated acetabular revision with a dual mobility cup for recurrent dislocation of the prosthesis with a minimum follow-up of 1 year. Kaplan-Meier survival analyses were performed with dislocation as a primary endpoint and re-revision for any reason as a secondary endpoint. RESULTS: Forty-nine consecutive patients (50 hips) were included; none of the patients was lost to follow-up. The median follow-up was 29 months (range 12-66 months). Two patients died from unrelated causes. Survival after 56 months was 100 % based on dislocation and 93 % (95 % CI 79-98 %) based on re-revision for any reason. Radiologic analysis revealed no osteolysis or radiolucent lines around the acetabular component during the follow-up period. CONCLUSION: The dual mobility cup is an efficient solution for instability of THA with a favorable implant survival at 56 months. LEVEL OF EVIDENCE: Level 4, retrospective case series.

Arthrodesis of the knee following failed arthroplasty.

PURPOSE: Primary stability in arthrodesis of the knee can be achieved by external fixation, intramedullary nailing or plate fixation. Each method has different features and results. We present a practical algorithm for arthrodesis of the knee following a failed (infected) arthroplasty, based on our own results and a literature review. METHODS: Between 2004 and 2010, patients were included with an indication for arthrodesis after failed (revision) arthroplasty of the knee. Patients were analyzed with respect to indication, fusion method and bone contact. End-point was solid fusion. RESULTS: Twenty-six arthrodeses were performed. Eighteen patients were treated because of an infected arthroplasty. In total, ten external fixators, ten intramedullary nails and six plate fixations were applied; solid fusion was achieved in 3/10, 8/10 and 3/6, respectively. CONCLUSIONS: There is no definite answer as to which method is superior in performing an arthrodesis of the knee. Intramedullary nailing achieved the best fusion rates, but was used most in cases without--or cured--infection. Our data and the contemporary literature suggest that external fixation can be abandoned as standard fusion method, but can be of use following persisting infection. The Ilizarov circular external fixator, however, seems to render high fusion rates. Good patient selection and appropriate individual treatment are the key to a successful arthrodesis. Based upon these findings, a practical algorithm was developed.

In vivo wear reduction of argon compared to air sterilized UHMW-polyethylene liners.

INTRODUCTION: To date, no studies have been published that report on the in vivo advantages of sterilisation in argon (ARGON) versus air (AIR) of UHMWPE liners with respect to wear extend and pattern in uncemented total hip arthroplasty. METHOD: Femoral penetration rates were measured in 93 AIR and 79 ARGON liners, during a mean follow-up of 8 (3-12) years. RESULTS: During the first 3 years after implantation, both groups showed no differences in mean wear rate (P = 0.13). Thereafter, the ARGON liner demonstrated a decrease in wear rate of 0.04 mm/year from 4 to 6 years (P = 0.006), 0.14 mm/year from 7 to 9 years (P < 0.001), and 0.33 mm/year beyond 9 years follow-up (P = 0.015) compared to the AIR liner. One AIR acetabular component required revision.

Porous-coated femoral components with or without hydroxyapatite in primary uncemented total hip arthroplasty: a systematic review of randomized controlled trials.

The purpose of this systematic review was to determine the clinical and radiologic benefit of hydroxyapatite coating in uncemented primary total hip arthroplasty. A database of Medline articles published up to September 2007 was compiled and screened. Eight studies involving 857 patients were included in the review. Pooled analysis for Harris hip score as a clinical outcome measure demonstrated no advantage of the hydroxyapatite coating (WMD: 1.49, P = 0.44). Radiologically, both groups showed equal presence of endosteal bone ingrowth (RR: 1.04, P = 0.66) and radioactive lines (RR: 1.02, P = 0.74) in the surface area of the prosthesis. This meta-analysis demonstrates neither clinical nor radiologic benefits on the application of a hydroxyapatite coating on a femoral component in uncemented primary total hip arthroplasty.

[How many steps does a doctor take in the hospital? No difference between internists and general surgeons, but a relationship with age and BMI]. / Hoeveel stappen zet een dokter in het ziekenhuis? Geen verschil tussen internisten en algemeen chirurgen, maar wel samenhang met leeftijd en BMI.

OBJECTIVE: To determine the number of steps taken during working days in the hospital by both internists and general surgeons and whether there is a difference between housemen, registrars and members of the staff. DESIGN: Comparative analysis. METHOD: A validated pedometer was used to count the number of steps taken by housemen, registrars and staff members in the departments of internal medicine and general surgery. The 2 groups of doctors comprised 131 subjects from 13 training hospitals. Possible factors likely to affect the number of steps, such as age, sex, weight and height, were recorded. RESULTS: The average number of steps taken per day was 5325 (range: 1105-10,250) and the average number per hour was 548 (range: 143-1105), with an average working day of 9.8 hours and 8.4 measured days. When corrected for age, sex and hierarchic status, no significant difference was observed between surgeons and internists (p = 0.097). There were also no differences within the hierarchic structure after correction (p = 0.936). Age and BMI seemed to be the most important factors predicting the number of steps in this population. Each additional year of age corresponded with an average decrease of 5 steps per hour on the job (p = 0.001), while each point rise in BMI (+1 kg/m) coincided with an average decrease of 20 steps per hour (p = 0.001). CONCLUSION: After correcting for confounding factors, no differences were observed in the number of steps taken in the hospital by general surgeons and internists. There was also no difference between hierarchic levels. Age and BMI were the most important variables that predicted the number of steps taken per hour in this research population.

Mid-term wear characteristics of an uncemented acetabular component.

We investigated the rate of polyethylene wear of a cementless acetabular component at different periods of follow-up in order to test the hypothesis than an irrecoverable deformation process (creep) was followed by an initially low, but gradually increasing wear rate. We studied prospectively 93 uncemented total hip arthroplasties in 83 patients (mean age 50 years (22 to 63)) with a mean follow-up of 8.2 years (3 to 12). We measured the penetration of the femoral head from radiographs taken immediately after surgery at three, six and nine years, or at the latest follow-up. The median wear rate was 0.17 mm per year in the first three years, a finding which we considered to be caused by creep. Thereafter, the rate of wear declined to 0.07 mm per year (four- to six-year period) and then increased to 0.17 mm per year (seven to nine years) and 0.27 mm per year (more than nine years), which we considered to be a reflection of genuine polyethylene wear. After the nine-year follow-up the wear rates were higher in patients with marked osteolysis. We found no relationship between the inclination angle of the acetabular component or femoral head orientation and the rate of wear. No acetabular component required revision.