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Periprosthetic infections following total knee arthroplasty (TKA) are diagnostically challenging. We evaluated the sensitivity and specificity of ESR and CRP, false negative rates, whether false negative rates differed between early post-operative and late infections, and the predictive ability of ESR and CRP to differentiate infected patients. Between 2000 and 2007, a prospectively collected database was reviewed to identify patients with suspected periprosthetic infections, and who had ESR and CRP laboratory values. One hundred and thirteen patients were identified. False negative rates were calculated. Finally, receiver operating characteristic curves were used to determine the predictive ability of ESR and CRP to differentiate infected from non-infected patients. CRP had a sensitivity of 95% and specificity of 20%. ESR had a sensitivity of 91% and a specificity of 33%. The false negative rate was 9.2% for ESR, 5.3% for CRP, and 11.1% for combined ESR and CRP. False negative rates were higher for early post-operative infections. Although ESR and CRP can be excellent adjunctive diagnostic tools, we emphasise that because some patients may not mount a sufficient immune response, the entire clinical picture must be evaluated, and periprosthetic infection should not be ruled out on the basis of ESR and CRP results alone. [ABSTRACT FROM AUTHOR]

The primary goals of this critical literature review were to determine whether revision rates of primary total hip arthroplasty in patients with osteonecrosis differ based on the underlying associated risk factors and diagnoses, whether the outcomes of this procedure have improved over the past two decades, and to compare outcomes based on study level of evidence. A systematic literature review yielded 67 reports representing 3,277 hips in 2,593 patients who had a total hip arthroplasty for osteonecrosis of the femoral head. Stratification of outcomes by associated risk factors or diagnoses revealed significantly lower revision rates in patients with idiopathic disease, systemic lupus erythematosus, and after heart transplant, and significantly higher rates in patients with sickle cell disease, Gaucher disease, or after renal failure and/or transplant. There was a significant decrease in revision rates between patients operated upon before 1990 versus those in 1990 or later, with rates of 17% and 3%, respectively. The results for arthroplasties performed in 1990 or later were similar to those for all hips in publicly reported national joint registries. Certain risk factors were associated with higher revision rates in patients with osteonecrosis who were treated by total hip arthroplasty. However, most patients (82%) do not have these associated negative risk factors. Overall, this critical literature review provides evidence that osteonecrosis itself, or when associated with the most common risk factors and/or diagnoses, is not associated with poor outcomes in total hip arthroplasty. [ABSTRACT FROM AUTHOR]

Surgical site infections following elective knee arthroplasties occur most commonly as a result of colonisation by the patient's native skin flora. The purpose of this study was to evaluate the incidence of deep surgical site infections in knee arthroplasty patients who used an advance cutaneous disinfection protocol and who were compared to patients who had peri-operative preparation only. All adult reconstruction surgeons at a single institution were approached to voluntarily provide patients with chlorhexidine gluconate-impregnated cloths and a printed sheet instructing their use the night before and morning of surgery. Records for all knee arthroplasties performed between January 2007 and December 2008 were reviewed to determine the incidence of deep incisional and periprosthetic surgical site infections. Overall, the advance pre-operative protocol was used in 136 of 912 total knee arthroplasties (15%). A lower incidence of surgical site infection was found in patients who used the advance cutaneous preparation protocol as compared to patients who used the in-hospital protocol alone. These findings were maintained when patients were stratified by surgical infection risk category. No surgical site infections occurred in the 136 patients who completed the protocol as compared to 21 infections in 711 procedures (3.0%) performed in patients who did not. Patient-directed skin disinfection using chlorhexidine gluconate-impregnated cloths the evening before, and the morning of, elective knee arthroplasty appeared to effectively reduce the incidence of surgical site infection when compared to patients who underwent in-hospital skin preparation only.

Dislocation is one of the most common complications of total hip arthroplasty. The use of constrained liners is an option for the management of chronic hip instability, typically used after other methods have failed. The purposes of this study were to evaluate the overall clinical outcomes and failure rates of a tripolar constrained liner design, to assess the radiographic outcomes of its use, and to examine whether various factors such as abductor mechanism quality and history of previous revision surgeries were associated with an increased risk of failure. Forty-three hips in 39 patients who had a mean follow-up of 51 months (range, 24-110 months) were reviewed. Ninety-one percent of the hips (39 of 43 hips) did not need any revisions over the study period. A new liner was implanted in all four failed hips with concurrent revision of the acetabular cup in three cases. No further dislocations occurred in this group. The mean hip score for surviving hips was 82 points (range, 38-100 points) at final follow-up. Radiographic evaluation revealed stable, well-fixed acetabular components in all surviving hips without progressive radiolucencies. No association was found between abductor muscle quality and the incidence of failure, but patients who experienced a constrained liner failure were more likely to have undergone at least one previous hip revision operation. Tripolar constrained acetabular liners can provide successful outcomes in patients with hip instability, although it is important not to rely on the use of a constrained liner alone in an attempt to compensate for other correctable factors such as component positioning.

The purpose of this study was to compare the incidence of reinfection in patients who received oral antibiotic prophylaxis with those who did not following two-stage revision knee arthroplasty. Additional purposes included: (1) comparison of these findings to the infection rate in patients who underwent revision for aseptic reasons, and (2) characterisation of the organisms responsible for reinfection following revision procedures. Twenty-eight two-stage revision knee arthroplasty procedures were followed up by a mean of 33 days of oral antibiotics (range, 28-43 days), while the remaining 38 procedures received only 24-72 hours of in-patient antibiotics. The incidence of reinfection in each group within 12 months was compared. The reinfection rates were additionally compared to those of 237 patients who underwent revision for aseptic loosening over the same time period. Patients who were treated with postoperative antibiotic prophylaxis had a considerably lower reinfection rate, with one reinfection in the prophylaxis group (4%), compared to six reinfections in the no-prophylaxis group (16%). The reinfection rates remained higher compared to those found in patients who underwent revision knee arthroplasty for aseptic loosening (1 of 237 patients; 0.4%). Both high and low virulence organisms were identified in the patients who were subsequently reinfected. A minimum of 28 days of postoperative oral antibiotics appeared to decrease reinfection rates following two-stage revision knee arthroplasty. These results suggest that the use of oral antibiotic prophylaxis following re-implantation may be appropriate in all patients undergoing two-stage revision, even in the absence of any signs of active infection.

The primary purpose of this study was to compare clinical and functional results of bilateral total knee arthroplasties in which a conventional total knee replacement was initially performed on one knee and a minimally invasive total knee replacement was later performed on the contralateral side. Operative factors, clinical and radiographic outcomes, and quadriceps muscle strength were evaluated in twenty-five patients (50 total knee arthroplasties). Twenty-one of the 25 patients preferred the minimally invasive approach. Knee society objective scores and range-of-motion were significantly greater in the minimally invasive group. Isokinetic testing demonstrated statistically improved quadriceps muscle strength in the minimally invasive technique group compared to the standard approach at both 12 weeks and one year postoperatively. Radiographic analysis did not reveal differences in alignment variables between the two approaches. The results of this study suggest that minimally invasive total knee arthroplasty offers superior short-term as well as possible long-term results.