Khalid Azzam

Periprosthetic joint infection: the economic impact of methicillin-resistant infections.

The orthopedic community has begun to witness a worrisome rise in the incidence of periprosthetic joint infections (PJIs) caused by resistant organisms. Besides other challenges associated with treating these infections, it appears that these infections may pose a higher cost compared to infections caused by sensitive organisms. Significantly higher cost of care for treatment of infections due to methicillin-resistant organisms were seen at a mean of

Periprosthetic Infection Due to Resistant Staphylococci: Serious Problems on the Horizon

107,264 per case compared to

Irrigation and debridement in the management of prosthetic joint infection: traditional indications revisited.

68,053 for treating PJI caused by sensitive strains (P < .0001). More effective strategies for preventing the spread of infections caused by resistant organisms need to be implemented to ease the social and economic strains facing the orthopedic community due to resistant organisms.

Staged Revision for Knee Arthroplasty Infection: What Is the Role of Serologic Tests Before Reimplantation?

AbstractProsthetic joint infections (PJI) caused by methicillin-resistant staphylococci represent a major therapeutic challenge. We examined the effectiveness of surgical treatment in treating infection of total hip or knee arthroplasty caused by methicillin-resistant staphylococcal strains and the variables influencing treatment success. One hundred and twenty-seven patients were treated at our institution between 1999 and 2006. There were 58 men and 69 women, with an average age of 66xa0years. Patients were followed for a minimum of 2xa0years or until recurrence of infection. Débridement and retention of the prosthesis was performed in 35 patients and resection arthroplasty in 92. Débridement controlled the infection in only 37% of cases whereas two-stage exchange arthroplasty controlled the infection in 75% of hips and 60% of knees. Preexisting cardiac disease was associated with a higher likelihood of failure to control infection in all treatment groups. Antibiotic-resistant Staphylococci continue to compromise treatment outcome of prosthetic joint infections, especially in patients with medical comorbidities. New preventive and therapeutic strategies are needed.n Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Microbiological, clinical, and surgical features of fungal prosthetic joint infections: a multi-institutional experience.

Irrigation and debridement (I and D) is a procedure commonly used for the treatment of acute periprosthetic infection. This study retrospectively reviewed clinical records of patients with periprosthetic infection of the hip or knee who underwent I and D with retention of their prostheses between 1997 and 2005 at a single institution. One hundred four patients (44 males and 60 females) were identified. Mean age at time of initial debridement was 65 years. Average follow-up was 5.7 years. Treatment failure was defined as the need for resection arthroplasty or recurrent microbiologically proven infection. According to these criteria, I and D was successful in 46 patients (44%). Patients with staphylococcal infection, elevated American Society of Anesthesiologists score, and purulence around the prosthesis were more likely to fail. The high failure rate of this procedure implies that it should be preferably limited to select healthy patients with low virulence organisms and equivocal intraoperative findings.

Outcome of a second two-stage reimplantation for periprosthetic knee infection.

Erythrocyte sedimentation rate and C-reactive protein are common preoperative diagnostic markers for prosthetic joint infection but their prognostic role before reimplantation has yet to be defined. We therefore determined the prognostic value of erythrocyte sedimentation rate and C-reactive protein performed before second-stage reimplantation for the treatment of infected total knee arthroplasty (TKA). We studied 109 patients who had undergone two-stage revision TKA for sepsis from 1999 to 2006. Receiver operating characteristic curves were constructed to determine the discriminatory value of erythrocyte sedimentation rate and C-reactive protein before reimplantation in predicting persistent infection. Twenty-three of the 109 patients (21%) required revision surgery for recurrence of prosthetic joint infection. The receiver operating characteristic areas under the curve suggested erythrocyte sedimentation rate and C-reactive protein poorly predicted persistent infection after TKA reimplantation. Cutoff values could not be obtained because of the high variance. We reached similar conclusions regarding the change in erythrocyte sedimentation rate and C-reactive protein levels from time of resection. More accurate diagnostic tools are needed to support clinical judgment in monitoring infection progress and thus deciding whether to proceed with TKA reimplantation.Level of Evidence: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Limitations of the Knee Society Score in evaluating outcomes following revision total knee arthroplasty.

Periprosthetic joint infection is one of the most dreaded and complex complications of total joint arthroplasty. Periprosthetic joint infection is now the major cause of failure following total knee arthroplasty1 and the third most common cause of failure following total hip arthroplasty2. It is estimated that the prevalence of periprosthetic joint infection may be on the rise3. A wide variety of pathogens are known to cause periprosthetic joint infection, with the majority of infections being caused by gram-positive bacteria, especially staphylococcal species4,5. The treatment of a confirmed periprosthetic joint infection often includes the need for surgical intervention, and two-stage exchange arthroplasty is the most common mode of surgical treatment in North America. Two-stage exchange arthroplasty relies on removal of all foreign material and insertion of an antibiotic-impregnated cement spacer for the purpose of delivering high doses of antibiotics locally in the interval of time between the resection arthroplasty and subsequent reimplantation.nnPeriprosthetic infection with fungi, although rare, represents a diagnostic and therapeutic challenge to which clear guidelines have not yet been established. It is not known if the protocol for treatment of a bacterial periprosthetic joint infection can also be applied in the same manner to fungal infections. Patients with fungal periprosthetic joint infection are believed to be a different type of host with decreased cellular immunity, mostly due to an underlying cause of immunosuppression, such as malignant disease, drug therapies (antineoplastic agents, corticosteroids, or immunosuppressive drugs), overuse or inappropriate use of antibiotics, and indwelling catheters (urinary or parenteral hyperalimentation). Other factors, such as diabetes, tuberculosis, intravenous drug use, and acquired immunosuppressive disease, are associated with an increased frequency of mycotic infection6. The lack of reliable antifungal medications for systemic and, in particular, local delivery poses a real challenge …

Deep venous thrombosis prophylaxis for total joint arthroplasty: American Academy of Orthopaedic Surgeons guidelines.

AbstractRecurrent or persistent infection after two-stage exchange arthroplasty for previously infected total knee replacement is a challenging clinical situation. We asked whether a second two-stage procedure could eradicate the infection and preserve knee function. We evaluated 18 selected patients with failed two-stage total knee arthroplasty implantation treated with a second two-stage reimplantation between 1999 and 2005. Failure of treatment was defined as recurrence or persistence of infection. The minimum followup was 24xa0months (mean, 40xa0months; range, 24–83xa0months). Recurrent or persistent infection was diagnosed in four of 18 patients, two of whom were successfully treated with a third two-stage exchange arthroplasty. Knee Society score questionnaires administered at the last followup showed an average Knee Society knee score of 73 points (range, 24–100 points) and an average functional score of 49 points (range, 20–90 points). The data suggest repeat two-stage exchange arthroplasty is a reasonable option for eradicating periprosthetic infection, relieving pain, and achieving a satisfactory level of function for some patients.n Level of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Revision of the unstable total knee arthroplasty: outcome predictors.

BACKGROUNDnTraditionally, the results of revision total knee arthroplasty have been determined with use of surgeon-based measures such as the Knee Society rating system. Recently, outcome and quality-of-life measures have shifted toward a greater emphasis on patient-based evaluation. The aim of our study was to determine the validity and responsiveness of the Knee Society rating system compared with the Short Form-36 health survey (SF-36), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and a four-question 4-point Likert scale satisfaction questionnaire following revision total knee arthroplasty.nnnMETHODSnA total of 152 patients underwent revision total knee arthroplasty at our institution, between August 2003 and January 2007, and had a two-year follow-up evaluation after revision surgery. The SF-36, WOMAC, Knee Society rating system, and satisfaction scores were completed preoperatively and postoperatively. Spearman correlation coefficients were calculated to determine the degree of correlation for each outcome scale. The SF-36, WOMAC, and patient satisfaction were correlated with the Knee Society rating system.nnnRESULTSnBoth before and after surgery, the correlation among items of the Knee Society rating system displayed low to negligible levels of association. The Knee Society rating system pain score showed modest levels of convergent construct validity with the WOMAC and SF-36. However, the Knee Society functional score displayed negligible to low correlation with its WOMAC functional counterpart preoperatively. The Knee Society pain and functional scores, respectively, showed marked and moderate association with satisfaction. The change in the Knee Society pain and functional scores had moderate association with the SF-36 and WOMAC counterparts, except low correlation was displayed between the pain scores for the Knee Society rating system and the SF-36. The Knee Society rating system pain score was found to be the most responsive of the measures with a standardized response mean of 1.6, whereas the Knee Society rating system functional score was found to be the least responsive at 0.7.nnnCONCLUSIONSnCurrently, there is no so-called gold standard that optimally reflects the status of the knee, as well as the patient, prior to and following revision total knee arthroplasty. Ideally, numerous assessment scales should be administered to the patient in order to accurately reflect the patient characteristics for the purpose of academic study, but from a practical standpoint, this may not be feasible. We encourage further research and development of a simple and concise standardized questionnaire for use before and after revision total knee arthroplasty.

Early Failure of a Nonmodular Titanium Femoral Stem After Primary Hip Arthroplasty

The orthopedic community continues to face a challenge with regard to the prevention of thromboembolism after total joint arthroplasty. The first and foremost issue facing surgeons is how to select the best agent or modality that is effective in preventing the untoward consequences of thromboembolism without causing other complications that can have dire consequences. Other challenges include the uncertainty regarding the dose and duration of various agents, the value of mechanical prophylaxis alone, and the exact end points that should be used to measure the efficacy of prophylaxis. This article discusses some of the recent developments in prevention and management of thromboembolism after total joint arthroplasty, in particular highlighting the guidelines that were developed by American Academy of Orthopedic Surgeons.