Introduction

Bilateral TKA is proven to be safe in a select group of patients. Patients with symptomatic bilateral knee arthritis who are not candidates for simultaneous bilateral TKA are subjected to staged surgery. The main objective of this study is to determine the safe window when second TKA can be performed in patients requiring bilateral TKA

Introduction

Recovery after total knee arthroplasty (TKA) may take longer than patients expect. Furthermore, there are a subset of patients who still experience pain and dissatisfaction despite normal physical examination, radiographs, and laboratory analysis. Corticosteroid injection (CSI) is commonly used nonsurgical treatment for painful knee arthritis. However, the efficacy of CSI in patients with a painful TKA remains unknown.

Purpose: Recently an orthopedic manufacturer has introduced a gender specific knee design implying that there is a substantial anatomical difference between the genders. If such concept is true then TKA prosthesis implanted in the female population over the last decades, by definition, must have suboptimal outcome when compared to the male patients. The purpose of this study was to examine the functional outcome, the incidence of complications, and the need for revision between the two genders receiving the same knee design.

Method: The study selected a matched group of 150 men and 250 women undergoing TKA at our instituion. The patients were matched for age, BMI, pre-op diagnosis, comorbidities, race, mode of fixation, and the type of implant. Other demographic, surgical, and medical factors between the two genders were similar. Both pre-op and post-op functional scores were compared between the two groups. Pre-op and post-op radiographic images were assessed for implant fit.

Results: There was a significant improvement in functional outcome as measured by Knee Society score, WOMAC, and SF-36 for all patients. The improvement in functional outcome was not different between the two groups. The incidence of complications, reoperations, and need for revision between the two genders was also not significantly different.

Conclusion: Total knee arthroplasty continues to be an effective surgical procedure. Both genders appear to enjoy relief of pain and improvement of function equally. Based on this retrospective study the use of non-gender specific knee prosthesis did not seem to result in suboptimal outcome in female patients. There appears to be little merit in introduction of gender specific knee designs when previous non-gender specific prosthesis appeared to function well in both genders.

The differential diagnosis of pain after total knee arthroplasty (TKA) should always include periprosthetic infection (PPI). The current diagnostic tools vary in sensitivity, specificity, and predictive value. Currently there is no test with an absolute accuracy for diagnosis of PPI. Furthermore, cost effectiveness of investigations has become an important issue in recent years as increased expenses can place an unnecessary heavy burden on the medical system.

We retrospectively evaluated 296 patients who underwent revision TKA at our institution during 2000–2005 and had preoperative erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) performed. The criteria used for diagnosing infection were a positive intraoperative culture on solid media, presence of an abscess or sinus tract that communicated with the joint, positive preoperative aspiration culture, and/or elevated fluid cell count and neutrophil differential of the aspirated fluid. The sensitivity, specificity, and predictive values of ESR and CRP were determined. Combinations were performed in parallel that necessitate both tests to be negative to rule out infection. The cost of each serological test was compared to that of other commonly used screening modalities.

One hundred and sixteen patients (39%) were classified as infected and 180 patients (61%) were considered non-infected. The sensitivity, specificity, positive predictive value, and negative predictive value for the ESR were: 91%, 72%, 68%, and 93%. The sensitivity, specificity, positive predictive value, and negative predictive value for the CRP were: 94%, 74%, 70%, and 95%. The sensitivity and negative predictive value for the combined studies were 96% and 95%, respectively. However, five infected patients (4%) had a normal

ESR and CRP. An organism was cultured on solid media in 4 of the 5 cases. ESR and CRP were the least costly of all the preoperative tests including radionuclide imaging and joint fluid analysis. ESR and CRP are important preoperative tests in diagnosis of PPI and their ability to clench the diagnosis in the majority of cases should not be underestimated. When combined, these simple serological tests have improved sensitivity and negative predictive value to rule out infection.