Lluís Puig-Verdié

Improved Diagnosis of Orthopedic Implant-Associated Infection by Inoculation of Sonication Fluid into Blood Culture Bottles

ABSTRACT Sonication improved the diagnosis of orthopedic implant-associated infections (OIAI). We investigated the diagnostic performance of sonication fluid inoculated into blood culture bottles in comparison with that of intraoperative tissue and sonication fluid cultures. Consecutive patients with removed orthopedic hardware were prospectively included and classified as having OIAI or aseptic failure (AF) according to standardized criteria. The diagnostic procedure included the collection of five intraoperative tissue cultures and sonication of the removed device, followed by conventional culture of the sonication fluid. Cultures were incubated for 7 days (aerobic) or 14 days (anaerobic). In addition, 10 ml of sonication fluid was inoculated into each aerobic and anaerobic BacT/Alert FAN blood culture bottle and incubated in the automated blood culture system for 5 days. Of 75 included patients, 39 had OIAI and 36 AF. The sensitivity of sonication fluid inoculated into blood culture bottles (100%) was higher than that of conventional sonication fluid (87%; P = 0.05) or intraoperative tissue cultures (59%; P < 0.01). Previous antibiotic therapy reduced the culture sensitivity of conventional sonication fluid to 77% and that of intraoperative tissue to 55%, while it remained 100% for blood culture-inoculated sonication fluid. The time to positivity was shorter in blood culture-inoculated sonication fluid, with detection of 72% of microorganisms after 1 day of incubation, than for intraoperative tissue and conventional sonication fluid cultures, with detection of 18% and 28% of microorganisms, respectively. In conclusion, compared to conventional sonication fluid and intraoperative tissue cultures, sonication fluid inoculated into blood culture bottles improved the diagnosis of OIAI and considerably reduced the time to culture positivity.

Influence of Depression on Total Knee Arthroplasty Outcomes

It is not clear whether indicating TKA-surgery is advisable in depressed patients. A prospective cohort of 716 patients undergoing TKA was designed. SF36, KSS, WOMAC and VAS plus 2 satisfaction questions were evaluated. There were 2 groups: 200 patients were depressed and 516 were not. Preoperative/postoperative results show better scores for non-depressed patients on almost every sub-scale. Nevertheless, net change results (improvement) were quite similar: 65.74 improvement in depressed-KSS and 74.58 in non-depressed (P=0.049); 8.93 net change in depressed-Physical Composite Score and 11.84 in non-depressed (P=0.003); 2.38 in depressed-Mental Composite Score and -0.61 in non-depressed (P=0.024). Depressed patients obtained great improvement from preoperative at one-year follow-up and even greater than non-depressed patients in some domains. Moreover, satisfaction was similar. Therefore, TKA can be recommended to depressed patients.

Use of antibiotic-loaded cement in total knee arthroplasty

Bone cement has the capacity to release antibiotic molecules if any antibiotic is included in it, and these elution properties are improved as cement porosity is increased. In vitro studies have shown high local antibiotic concentration for many hours or few days after its use. Antibiotic loaded bone cement (ALBC) is helpful when treating an infection in total knee arthroplasty (TKA) revision surgery. The purpose of this paper was to review the evidence for the routine use of ALBC in TKA in the literature, its pros and cons. Many authors have recommended the use of ALBC also in primary TKA for infection prophylaxis, but the evidence based on data from National Registries, randomized clinical trials and meta-analysis suggest a protective effect of ALBC against infection when used in hips, but not (or only mild) in knees. A possible explanation to this finding is that the duration and quantity of locally elevated antibiotic levels after surgery are smaller in TKA, due to the smaller amount of cement used for fixation in TKA-only a layer in the bone surface. There are some concerns about the routine use of ALBC in primary TKA as prophylaxis against infection: Firstly, there is a risk of hypersensivity or toxicity even when the chance is highly improbable. Secondly, there is a reduction in the mechanical properties of the cement, but this can be probably neglected if the antibiotic is used in low doses, not more than 1 g per 40 g cement package. Another significant concern is the increased economic cost, which could be overlooked if there were enough savings in treating fewer prosthetic infections. Finally, there is also a risk of selection of antibiotic-resistant strains of bacteria and this could be the main concern. If used, the choice of the antibiotic mixed in ALBC should consider microbiological aspects (broad antimicrobial spectrum and low rate of resistant bacteria), physical and chemical aspects (thermal stability, high water solubility), pharmacological characteristics (low risk to allergic reactions or toxicity) and economic aspects (not too expensive). The most commonly used antibiotics in ALBC are gentamicin, tobramycin and vancomycin. In conclusion, there is a paucity of randomized clinical trials in the use of ALBC in primary TKAs and the actual evidence of the effect of ALBC in reducing the risk of infection is insufficient. This, in addition to concerns about patient safety, risks of increase in the antibiotic resistance of microorganisms and the increase in costs in the procedure, lead us to recommend a cautious use of ALBC, perhaps only in high-risk patients (immunocompromised, morbidly obese, diabetic and patients with previous history of fracture or infection around the knee) unless the benefits of ALBC use were fully proven. Meanwhile, the rigorous use of peri-operative prophylactic systemic antibiotics and adoption of efficient antiseptic procedures and improved surgical techniques must be considered the gold standard in infection prevention in TKA surgery.

Highly crosslinked polyethylene does not reduce the wear in total knee arthroplasty: in vivo study of particles in synovial fluid.

The aim was to assess if the reduction in polyethylene wear with highly crosslinked polyethylene suggested by studies with knee simulators is confirmed in patients with a knee arthroplasty. The use of a conventional or a highly crosslinked polyethylene was randomly assigned intraoperatively. Twelve months after surgery a knee arthrocentesis was performed and the synovial fluid of 17 patients in each group was studied analysing the number, size and shape of the polyethylene particles by scanning electron microscope. We found no significant differences in the concentration, size or morphology of polyethylene particles between groups. The great variability in the number of particles between individuals suggests that in vivo polyethylene wear depends on many factors and probably the type of polyethylene is not the most significant.

Preoperative antibiotic prophylaxis in prosthetic joint infections: not a concern for intraoperative cultures

BACKGROUND Culture negative prosthetic joint infections (PJI) still remain an issue even with the advantages of the new diagnostic tools for PJI. This is why some orthopedic surgeons have reservations relative to the use of preoperative antibiotic prophylaxis when a PJI is suspected. The purpose of the present study was to evaluate the influence of preoperative antibiotic prophylaxis on intraoperative cultures. MATERIAL AND METHODS An enhanced diagnostic protocol for PJI (Zimmerli criteria) was used for the inclusion criteria in order to collect all PJI that were seen in a university hospital. Patients were prospectively randomized into two groups. The control group received the classical preoperative antibiotic prophylaxis. The study group did not receive prophylaxis prior to surgery. RESULTS There were 14 patients in each group. They correspond to 13 total hip arthroplasty infections, 12 total knee arthroplasty infections and 3 reverse shoulder prosthesis infections. There were 10 patients in the study group and 10 patients in the control group with at least one positive microbiological criterion (P > 0.05). There were 4 patients in each group with a culture negative PJI (P > 0.05). CONCLUSIONS Preoperative antibiotic prophylaxis does not affect intraoperative cultures in suspected or confirmed PJI. Therefore it is essential to deliver antibiotic prophylaxis in any patient in which a prosthesis is to be implanted in order to protect the prosthesis from infection.

Long Term Follow-Up of Successfully Treated Superficial Wound Infections Following TKA

The relevance of wound complications in association with acute prosthetic joint infection (PJI) is well known. However, whether a successfully treated superficial infection can result in a chronic deep infection remains unclear. The aim of this study was to determine the prevalence, treatment and late complications of superficial wound infections following TKA. In a 3000 TKA prospective cohort, 45 superficial infections were diagnosed and treated successfully with antibiotic therapy along with or without surgical debridement. None of the cases developed deep chronic PJI at 70 months of follow-up. Three cases were in need of a TKA exchange due to aseptic loosening. A successfully treated superficial wound infection does not result in a chronic deep TKA infection.

Comparison of quality of life between elderly patients undergoing TKA.

The purpose of this study was to compare the short-term changes in quality of life for patients younger than 80 years with those 80 years and older undergoing total knee arthroplasty (TKA). It was hypothesized that patients 80 years and older had a similar quality of life after TKA compared with those younger than 80 years.All consecutive patients undergoing primary TKA were enrolled in this prospective, comparative, prognostic (level I evidence) study and were stratified into 2 groups based on their age (younger than 80 years and 80 years and older). Data on quality of life assessed using the Short Form 36 health survey were obtained preoperatively and 1 year postoperatively (short-term follow-up) and were compared between groups. A total of 328 (83.89%) patients younger than 80 years (mean age, 70.7 years) and 63 (16.11%) patients 80 years and older (mean age, 82.1 years) were included. No significant differences in preoperative quality of life were observed between groups. Postoperative physical function, vitality, social function, and physical component summary were lower in patients 80 years and older. Older patients had a lower difference between pre- and postoperative values in Short Form 36 physical function and role-emotional scores.Patients 80 years and older had a similar improvement in quality of life 1 year after TKA compared with patients younger than 80 years. Therefore, changes in quality of life justify TKA as a treatment option for elderly patients with end-stage knee osteoarthritis.

Distal Clavicle Osteolysis after Modified Weaver-Dunn’s Procedure for Chronic Acromioclavicular Dislocation: A Case Report and Review of Complications

Distal clavicle osteolysis after acromioclavicular joint stabilization has only been described after the use of hardware for clavicle stabilization or synthetic graft causing a foreign body reaction. This paper reports a very rare case of distal clavicle osteolysis after modified Weaver-Dunn procedure for the treatment of chronic acromioclavicular joint dislocation. The paper also provides a comprehensive review of complications of this surgical technique and discusses a potential vascular etiology and preventive strategies aimed at avoiding clavicle osteolysis.

Peri-operative Management in TKA

Total knee arthroplasty (TKA) has become the standard of care for patients with end-stage knee osteoarthritis (OA) and is one of the most frequently performed Orthopaedic procedures. Better knowledge of some complications that may occur in the TKA peri-operative period as they are infection, blood loss, thromboembolic events, and pain might allow for better management of the procedure from start to finish.

Cervical Paravertebral Osteolipoma: Case Report and Literature Review

Lipomas are the most frequent soft tissue tumors. Osteolipomas are a rare variant that can be difficult to diagnose. We report the case of a 66-year-old man consulting with a tumor of 2 years development in the right paravertebral cervical region. Neurologically, the patient had no sign of myelopathy or neurological focality. Magnetic resonance imaging showed a mass with a lipid component and calcifications inside within the right paravertebral musculature with a possible origin in the right C3 posterior root. A computed tomography scan and guided biopsy were performed, revealing hematic material and small bone spicules with no apparent neoplastic element. The tumor was totally removed, including the right C3 posterior branch, and was confirmed to be an osteolipoma on biopsy. The patient remains asymptomatic at 6-month follow-up. The osteolipoma is a benign tumor of soft tissue, characterized by lipoma areas with mature bone tissue differentiation, and even with hematopoietic marrow.