Michelle M. Dowsey

Does Accurate Anatomical Alignment Result in Better Function and Quality of Life? Comparing Conventional and Computer-Assisted Total Knee Arthroplasty

This is a randomized prospective controlled trial comparing the alignment, function, and patient quality-of-life outcomes between patients undergoing conventional (CONV) and computer-assisted (CAS) knee arthroplasty. One hundred and fifteen patients (60 CAS, 55 CONV) underwent cemented total knee arthroplasty. Three patients were lost to follow-up. Eighty-eight percent (CAS) vs 61% (CONV) of knees achieved a mechanical axis within 3 degrees of neutral (P = .003). Aligning femoral rotation with the epicondylar axis was accurately achieved in CAS and CONV with no significant difference. Patients with coronal alignment within 3 degrees of neutral had superior International Knee Society and Short-Form 12 physical scores at 6 weeks, 3 months, 6 months, and 12 months after surgery. Computer-assisted total knee arthroplasty achieves greater accuracy in implant alignment and this correlates with better knee function and improved quality of life.

Obesity is a Major Risk Factor for Prosthetic Infection after Primary Hip Arthroplasty

AbstractThe incidence of obesity and the number of hip arthroplasties being performed in Australia each year are increasing. Although uncommon, periprosthetic infection after surgery can have a devastating effect on patient outcomes. We therefore asked whether obesity correlated with periprosthetic infection after primary hip arthroplasty. We further asked whether variables such as patient comorbidities, operative time, blood transfusions, use of drains, and cementation practices correlated with periprosthetic infection. We hypothesized obesity was an independent risk factor for the development of acute periprosthetic infection after primary hip arthroplasty. We reviewed 1207 consecutive primary hip arthroplasties separating patients into four weight groups, normal, overweight, obese, and morbidly obese, and compared for incidence of periprosthetic infection between the groups. We observed a considerably higher infection rate in obese patients; the correlation was independent of patient comorbidities such as diabetes and cardiovascular disease. We also observed a correlation between infection rates and using a posterior approach in obese patients. The incidence of periprosthetic infection was not influenced by operative time, transfusion requirements, use of drains, and cementation practices. In this series, obesity was an independent risk factor for acute periprosthetic infection after primary hip arthroplasty. Level of Evidence: Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

The impact of pre-operative obesity on weight change and outcome in total knee replacement: A PROSPECTIVE STUDY OF 529 CONSECUTIVE PATIENTS

We carried out a prospective, continuous study on 529 patients who underwent primary total knee replacement between January 2006 and December 2007 at a major teaching hospital. The aim was to investigate weight change and the functional and clinical outcome in non-obese and obese groups at 12 months post-operatively. The patients were grouped according to their pre-operative body mass index (BMI) as follows: non-obese (BMI < 30 kg/m(2)), obese (BMI (3) 30 to 39 kg/m(2)) and morbidly obese (BMI > 40 kg/m(2)). The clinical outcome data were available for all patients and functional outcome data for 521 (98.5%). Overall, 318 (60.1%) of the patients were obese or morbidly obese. At 12 months, a clinically significant weight loss of > or =5% had occurred in 40 (12.6%) of the obese patients, but 107 (21%) gained weight. The change in the International Knee Society score was less in obese and morbidly obese compared with non-obese patients (p = 0.016). Adverse events occurred in 30 (14.2%) of the non-obese, 59 (22.6%) of the obese and 20 (35.1%) of the morbidly obese patients (p = 0.001).

Risk factors associated with acute hip prosthetic joint infections and outcome of treatment with a rifampin‐based regimen

Background and purpose Acute prosthetic infection is a serious problem. We report factors related to the incidence of acute infection and results of combined joint debridement and prolonged rifampicin-based antibiotic therapy. Patients and methods Between 1998 and 2004, 14 acute infections occurred after 819 primary hip arthroplasties. The association between patient-related and surgical factors and the risk of infection were analyzed. Infections were treated with multiple joint lavage, debridement, 2 weeks of antibiotic therapy, and then oral antibiotics for a minimum of 6 months. Results There was a correlation between having a body mass index (BMI) of ≥ 30, and also more than 2 co-morbidities, and an increased risk of infection. Diabetes was a potential risk factor. Following our regime of treatment, 11 of 14 patients retained their prosthesis. 2 of 3 who required resection arthroplasty underwent successful staged revision, while the third patient had no further surgery because of being deemed unfit. Interpretation Primary joint replacement was salvaged in 11 of 14 patients. When successful re-implanta-tion was included, 13 of 14 patients had a mobile prosthetic joint without further infection.

Risk factors for prosthetic hip and knee infections according to arthroplasty site.

Prosthetic joint infection is a devastating complication of arthroplasty. Previous epidemiological studies have assessed factors associated with arthroplasty infections but have not assessed the impact of comorbidity on infection at different arthroplasty locations. We used a case-control design to investigate risk factors for prosthetic joint infection with reference to the anatomical site. During an eight-year period at a single hospital, 63 patients developed a prosthetic joint infection (36 hips, 27 knees). Cases of prosthetic hip or knee joint infection were matched 1:2 to controls. The results suggest that factors associated with arthroplasty infections differ with anatomical location. Following knee arthroplasty, wound discharge was associated with an increased risk of prosthetic joint infection whereas the presence of a drain tube reduced the risk. By contrast, increased body mass index, increased drain tube loss and superficial incisional surgical site infections (SSIs) were associated with prosthetic hip infection. When analysed as a combined cohort, systemic steroid use, increased SSI drain tube losses, wound discharge, and superficial incisional SSIs were predictors of infection.

Coronal alignment correlates with outcome after total knee arthroplasty: five-year follow-up of a randomized controlled trial.

In a prospective randomized control trial comparing computer-assisted vs conventional total knee arthroplasty, we previously reported that patients with coronal alignment within 3° of neutral had superior international knee society and Short-Form 12 (SF-12) physical scores at 6 weeks, 3 months, 6 months, and 12 months after surgery. Computer-assisted total knee arthroplasty achieved greater accuracy in implant alignment, and this correlated with better knee function and quality of life. At 5 years, 90 of 111 patients assessed in our original study were reviewed. Coronal alignment within 3° of neutral continued to be correlated with superior International Knee Society and SF-12 scores. Coronal alignment greater than 3° was associated with a significant decline in SF-12 mental health scores.

EARLY OUTCOMES AND COMPLICATIONS FOLLOWING JOINT ARTHROPLASTY IN OBESE PATIENTS: A REVIEW OF THE PUBLISHED REPORTS

The incidence of obesity and the number of hip arthroplasties being carried out in Australia each year are significantly increasing. There is an overrepresentation of obesity among patients presenting for elective orthopaedic surgery. The aim of this study was to present a review of published works reporting on obesity and joint replacement surgery in terms of early clinical, functional and quality‐of‐life outcomes. We conducted a metasearch of databases, including PubMed, Web of Science and The Cochrane Library, from January 1990 to May 2007. Studies published in English with a primary intention of exploring the relationship between obesity and joint arthroplasty were reviewed and results summarized. Key issues identified in relation to obesity and joint replacement surgery included clinical outcomes and complications, functional and quality of life and the influence of arthroplasty surgery on the management of obesity. Reports on early outcomes, that is in the first 12 months following joint replacement surgery, were included in the review. Results for these three key issues were summarized and reported separately. There is evidence in the published reports to support a correlation between obesity and complications following joint replacement surgery. Obesity has been found to be a specific risk factor for joint infection. Research on early functional and quality‐of‐life data as well as on the influence arthroplasty surgery has on weight management is lacking, and few conclusions can be drawn from the published reports. A study of significant size that examines all three issues in conjunction would be of value in identifying patients at high risk of failure in terms of both clinical and quality‐of‐life perspectives.

Gram-negative prosthetic joint infection treated with debridement, prosthesis retention and antibiotic regimens including a fluoroquinolone

Information is required about treatment outcomes of Gram-negative prosthetic joint infections treated with prosthesis retention and surgical debridement, especially where biofilm-active antibiotics such as fluoroquinolones are used. The outcome of 17 consecutive patients with an early Gram-negative prosthetic joint infection who had been treated with prosthesis retention and surgical debridement was analysed. Enterobacteriaceae were isolated in 16 patients and infections were mixed with other organisms in 13 (76%) patients. The median joint age was 17 days and the median duration of symptoms before debridement was 7 days. All patients initially received intravenous β-lactam antibiotic therapy and 14 patients were then treated with oral ciprofloxacin. Treatment failure occurred in two patients over a median period of follow-up of 28 months. In only one patient was a relapsed Gram-negative infection responsible for the failure and this patient had not been treated with ciprofloxacin. The 2-year survival rate free of treatment failure was 94% (95% CI, 63-99%). Prosthesis retention with surgical debridement, in combination with antibiotic regimens including ciprofloxacin, was effective and should be considered for patients with early Gram-negative prosthetic joint infection.

Economic burden of obesity in primary total knee arthroplasty.

To compare the hospital inpatient costs between nonobese and obese patients and estimate the economic burden of obesity in primary total knee arthroplasty (TKA).

Cost analysis of debridement and retention for management of prosthetic joint infection.

Prosthetic joint infection remains one of the most devastating complications of arthroplasty. Debridement and retention of the prosthesis is an attractive management option in carefully selected patients. Despite this, there are no data investigating the cost of this management modality for prosthetic joint infections. The aim of this case-control study was to calculate the cost associated with debridement and retention for management of prosthetic joint infection compared with primary joint replacement surgery without prosthetic joint infection. From 1 January 2008 to 30 June 2010, there were 21 prosthetic joint infections matched to 42 control patients. Controls were matched to cases according to the arthroplasty site, age and sex. Cases had a greater number of unplanned readmissions (100% vs. 7.1%; p <0.001), more additional surgery (3.3 vs. 0.07; p <0.001) and longer total bed days (31.6 vs. 7.9 days; p <0.001). In addition they had more inpatient, outpatient and emergency department visits (p <0.001, respectively). For patients with prosthetic joint infection the total cost, including index operation and costs of management of the prosthetic joint infection, was 3.1 times the cost of primary arthoplasty; the mean cost for cases was Australian dollars (AUD)