Rotating Hinge Knee Arthroplasty for Revision Prosthetic-Knee Infection: Good Functional Outcomes but a Crucial Need for Superinfection Prevention.

Introduction: Management of chronic infection following total knee arthroplasty (TKA) is challenging. Rotating hinged prostheses are often required in this setting due to severe bone loss, ligamentous insufficiency, or a combination of the two. The nature of the mechanical and septic complications occurring in this setting has not been well-described. The aim of this study was to evaluate patient outcomes using a hinge knee prosthesis for prosthetic knee infections and to investigate risk factors for implant removal. Methods: This was a retrospective cohort study that included all patients treated in our tertiary level referral center between January 2009 and December 2016 for prosthetic knee infection with a hinge knee prosthesis. Only patients with a minimum 2-year of follow-up were included. Functional evaluation was performed using international knee society (IKS) "Knee" and "Function" scores. Survival analysis comparing implant removal risks for mechanical and septic causes was performed using Cox univariate analysis and Kaplan-Meier curves. Risk factors for implant removal and septic failure were assessed. Results: Forty-six knees were eligible for inclusion. The majority of patients had satisfactory functional outcomes as determined by mean IKS scores (mean knee score: 70.53, mean function score: 46.53 points, and mean knee flexion: 88.75°). The 2-year implant survival rate was 89% but dropped to 65% at 7 years follow-up. The risk of failure (i.e., implant removal) was higher for septic etiology compared to mechanical causes. Patients with American society of anesthesiologists (ASA) score>1, immunosuppression, or with peripheral arterial diseases had a higher risk for septic failure. Patients with acute infection according to the Tsukayamaclassification had a higher risk of failure. Of the 46 patients included, 19 (41.3%) had atleast one infectious event on the surgical knee and most of these were superinfections (14/19) with new pathogens isolated. Among pathogens responsible for superinfections (i) cefazolin and gentamicin were both active in six of the cases but failed to prevent the superinfection; (ii) cefazolin and/or gentamicin were not active in eight patients, leading to alternative systemic and/or local antimicrobial prophylaxis consideration. Conclusions: Patients with chronic total knee arthroplasty (TKA) infection, requiring revision using rotating hinge implant, had good functional outcomes but experienced a high rate of septic failure, mostly due to bacterial superinfection. These patients may need optimal antimicrobial systemic prophylaxis and innovative approaches to reduce the rate of superinfection.

Subcutaneous suppressive antibiotic therapy for bone and joint infections: safety and outcome in a cohort of 10 patients.

BACKGROUND: Optimal treatment of prosthetic joint infection and chronic osteomyelitis consists of surgical removal of biofilm-embedded bacteria, followed by a 6-12 week course of antimicrobial therapy. However, when optimal surgery is not feasible, oral prolonged suppressive antibiotic therapy (PSAT) is recommended to prevent prosthesis loosening and/or relapse of infection. Since 2010, we have used infection salvage therapy using off-label subcutaneous (sc) injection of a ß-lactam as PSAT for patients in whom oral PSAT is not possible. METHODS: A single-centre prospective cohort study (2010-18) reporting treatment modalities, efficacy and safety in all patients receiving sc PSAT. NCT03403608. RESULTS: The 10 included patients (median age 79 years) had polymicrobial (n = 5) or MDR bacterial (n = 4) prosthetic joint infection (knee, n = 4; hip, n = 3) or chronic osteomyelitis (n = 3). After initial intensive therapy, seven patients received ertapenem, three patients received ceftriaxone and one patient received ceftazidime by sc injection (one patient received 8 days of ceftriaxone before receiving ertapenem). In one patient, sc PSAT failed with recurrent signs of infection under treatment. In three patients, sc PSAT had to be discontinued due to side effects; in only one of these was the sc route implicated (skin necrosis following direct sc injection and not gravity infusion). Median treatment duration was 433 days. In six patients, sc PSAT was successful with favourable outcome at the time of writing. Interestingly, three patients with MDR bacterial carriage at baseline lost this under PSAT during follow-up. CONCLUSIONS: As salvage therapy, sc PSAT delivered by gravity infusion is a safe and interesting alternative when an optimal surgical strategy is not feasible and no oral treatment is available.

Prospective Cohort Study of the Tolerability of Prosthetic Joint Infection Empirical Antimicrobial Therapy.

The empirical use of vancomycin in combination with a broad-spectrum beta-lactam is currently recommended after the initial surgery of prosthetic joint infection (PJI). However, the tolerability of such high-dose intravenous regimens is poorly known. Adult patients receiving an empirical antimicrobial therapy (EAT) for a PJI were enrolled in a prospective cohort study (2011 to 2016). EAT-related adverse events (AE) were described according to the common terminology criteria for AE (CTCAE), and their determinants were assessed by logistic regression and Kaplan-Meier curve analysis. The EAT of the 333 included patients (median age, 69.8 years; interquartile range [IQR], 59.3 to 79.1 years) mostly relies on vancomycin (n = 229, 68.8%), piperacillin-tazobactam (n = 131, 39.3%), and/or third-generation cephalosporins (n = 50, 15%). Forty-two patients (12.6%) experienced an EAT-related AE. Ten (20.4%) AE were severe (CTCAE grade ≥ 3). The use of vancomycin (odds ratio [OR], 6.9; 95% confidence interval [95%CI], 2.1 to 22.9), piperacillin-tazobactam (OR, 3.7; 95%CI, 1.8 to 7.2), or the combination of both (OR, 4.1; 95%CI, 2.1 to 8.2) were the only AE predictors. Acute kidney injury (AKI) was the most common AE (n = 25; 51.0% of AE) and was also associated with the use of the vancomycin and piperacillin-tazobactam combination (OR, 6.7; 95%CI, 2.6 to 17.3). A vancomycin plasma overexposure was noted in nine (37.5%) of the vancomycin-related AKIs only. Other vancomycin-based therapies were significantly less at risk for AE and AKI. The EAT of PJI is associated with an important rate of AE, linked with the use of the vancomycin and the piperacillin-tazobactam combination. These results corroborate recent findings suggesting a synergic toxicity of these drugs in comparison to vancomycin-cefepime, which remains to be evaluated in PJI. (This study has been registered at ClinicalTrials.gov under identifier NCT03010293.).

The AES total ankle arthroplasty analysis of failures and survivorship at ten years.

BACKGROUND: AES mobile-bearing total ankle replacement was developed from the Buechel Pappas model. It was withdrawn in 2009, after identification of a higher than expected complication rate. The purpose of the current study was to analyse clinical outcomes, failures and survival of the initial series of 50 AES published in 2009. METHODS: In this single-centre continuous prospective study (2003-2006), 50 AES prostheses were included. Pre-operative osteoarthritis was mainly post-traumatic (50%) and secondary to instability (36%). All patients were assessed with clinical and radiographic follow-up at six months, one year, two years and every two to three years thereafter. A CT-scan was systematically performed before procedure, and at two years, five years and ten years. At last follow-up, all patients with TAR had a functional (SF 36, AOFAS) and clinical assessment. All complications or surgical events were analysed. RESULTS: The mean follow-up was ten ± two years (range, 9-13). The mean AOFAS score was 75 points (range, 26-100). The mean SF 36 score was 69 points (range, 35-97). There was a significant deterioration in AOFAS score at five years and at last follow-up (p < 0.05). Fifteen TARs underwent reoperation for cyst curettage-graft because of development of periprosthetic lesions. Six of them ended up with prosthesis removal-arthrodesis. At the last follow-up, 14 TARs were removed for arthrodesis. Of the 30 prostheses seen at last follow-up, four are awaiting prosthesis removal-arthrodesis and one for cyst curettage-graft. The ten year survivorships free of any prosthesis removal or arthrodesis and free of any reoperation were 68% (95% CI, 55-85) and 57% (95% CI, 44-74), respectively. CONCLUSION: Our data suggested a high rate of reoperation. Overall ten year survival was lower than with other designs, particularly due to cyst lesions. LEVEL OF EVIDENCE: Level IV, prospective case series.

Factors associated with Clostridium difficile infection: A nested case-control study in a three year prospective cohort.

BACKGROUND: Clostridium difficile infection (CDI) is a serious medical condition that is associated with substantial morbidity and mortality. Identification of risk factors associated with CDI and prompt recognition of patients at risk is key to successfully preventing CDI. METHODS: A 3-year prospective, observational, cohort study was conducted in a French university hospital and a nested case-control study was performed to identify risk factors for CDI. Inpatients aged 18 years or older, suffering from diarrhea suspected to be related to CDI, were asked to participate. RESULTS: A total of 945 patients were included, of which 233 cases had a confirmed CDI. CDI infection was more common in men (58.4%) (P = 0.04) compared with patients with diarrhea not related to C. difficile. Previous hospitalization (P < 0.001), prior treatment with antibiotics (P = 0.001) or antiperistaltics (P = 0.002), liver disease (P = 0.003), malnutrition (P < 0.001), and previous CDI (P < 0.001) were significantly more common in patients with CDI. Multivariate logistic regression analysis showed that exposure to antibiotics in the last 60 days (especially third generation cephalosporins and penicillins with ß-lactamase inhibitor), chronic renal or liver disease, malnutrition or previous CDI, were associated with an independent high risk of CDI. Age was not related with CDI. CONCLUSIONS: This study showed that antibiotics and some comorbid conditions were predictors of CDI. Patients at high risk of acquiring CDI at the time of admission may benefit from careful monitoring of antibiotic prescriptions and early attention to infection control issues. In future, these "high-risk" patients may benefit from novel agents being developed to prevent CDI.

The "comma sign": an anatomical investigation (dissection of the rotator interval in 14 cadaveric shoulders).

PURPOSE: The aim of the present study was to describe the precise anatomy of the so-called "Comma Sign" which has been observed during arthroscopy in retracted subscapularis (SSC) tears. METHODS: Fourteen fresh cadaveric shoulders were prepared to obtain an articular view comparable to arthroscopic posterior portal view. A step-by-step dissection was carried out to verify the presence of any anatomic structure inserting directly on the lateral margin of the SSC tendon. A sequential detachment of the superior gleno-humeral ligament (SGHL), the coraco-humeral ligament (CHL), and the SSC tendon from their bony humeral insertions was performed. Under intra-articular and extra-articular view, the SSC and its connections with the supraspinatus (SS), the SGHL and the CHL were evaluated. RESULTS: The detachment of the CHL and the SGHL from the humerus did not reveal any structure directly inserted on the superior-lateral margin of the SSC tendon. However, when the SSC tendon was excised from the lesser tuberosity and pulled medially, a bundle of fibers, which inserted directly onto its superior-lateral edge, was constantly observed. CONCLUSIONS: We constantly found an effective link between the superior-lateral corner of the SSC tendon and a bundle of fibers coming from SS and CHL. It became visible only after medial traction of the detached SSC. This structure yields the "Comma Sign" in subscapularis tendon tears.

Fixation failures of dual mobility cups: a mid-term study of 2601 hip replacements.

BACKGROUND: The use of dual-mobility cups has increased because of a low rate of dislocations combined with a 96% 15-year survival rate. However, late cup migrations have been attributed to their fixation (tripod - exact fit with two pegs and one extraacetabular screw) and the absence of porous coating. In a second-generation device, the designs were modified to achieve press-fit fixation and a layer of titanium beads was sintered on stainless steel cups. QUESTIONS/PURPOSES: We therefore (1) determined the midterm survival of press-fit, grit-blasted, second-generation cups with or without additional screws, compared with original tripod and (2) compared survival of grit-blasted dual-mobility cups with bimetallic porous-coated cups. METHODS: From a multiinstitutional trial, we reviewed 2408 patients with osteoarthritis implanted with 2601 prostheses of seven designs of a second-generation dual-mobility cup. The criteria for failure were migration, widening radiolucencies in any zone of the interface, or revision for cup loosening. The minimum followup was 5 years (mean, 7.7 years; range, 5-11 years). RESULTS: The 8-year survival rate of press-fit, grit-blasted cups was lower than that for press-fit, grit-blasted cups fixed with screws (91% versus 100%) and for tripod fixation (98%). The 8-year survival rate of press-fit, grit-blasted cups was less than that for press-fit, porous-coated cups made of the same alloy (91% versus 95%). CONCLUSIONS: The data suggested primary fixation of grit-blasted dual-mobility cups should be secured with screws. Porous coating sintered on the convex side improved midterm survivorship. No deleterious effect of metallosis resulted from sintered titanium beads on stainless steel. Long-term followup is required to confirm these findings.

Cementoplasty in the treatment of avascular necrosis of the hip.

OBJECTIVE: This retrospective study evaluated the role of percutaneous cementoplasty in the treatment of avascular necrosis (AVN) of the hip in order to postpone or avoid total hip replacement. METHODS: The study population comprised 40 patients (47 hips) with mean age of 46 +/- 4.7 years and mean body mass index of 26.7 +/- 4.6 kg/m(2). AVN was classified according to the Ficat-Arlet classification as one stage I, 30 stage II, and 16 stage III. The minimum followup was 9 months. RESULTS: It was found that 74.5% of hips were secondarily operated for total hip replacement a mean of 19.9 +/- 15 months (median 14 mo) after cementoplasty. As well, 94% of patients with stage 3AVN and 68% with stage 2AVN underwent surgery. Twelve hips were not operated, with a mean followup of 39 +/- 19.2 months. Pain decreased by more than 80% after cementoplasty in two-thirds of patients, but the mean pain-free interval was only 8.1 +/- 6.6 months (median 5 mo). Nineteen of the 29 working patients were able to transiently return to work. The outcome was more unfavorable with radiological stage III AVN, joint effusion, and/or a double-line sign around the lesions on magnetic resonance images. CONCLUSION: Despite early relief of pain, the results of the cementoplasty technique were disappointing, with need for arthroplasty surgery in most cases within 2 years. Alternative percutaneous techniques using different filler materials with osteoinductive properties should be evaluated in further studies.