Cognitive Reserve and Postoperative Delirium in Older Adults.

OBJECTIVES: To examine the role of cognitive reserve in reducing delirium incidence and severity in older adults undergoing surgery. DESIGN: Prospective cohort study. SETTING: Hospital. PARTICIPANTS: Older adults (mean age 71.2, 65% women) undergoing elective orthopedic surgery (N = 142). MEASUREMENTS: Incidence (Confusion Assessment Method) and severity (Memorial Delirium Assessment Scale) of postoperative delirium were the primary outcomes. Predictors included early- (literacy) and late-life (cognitive activities) proxies for cognitive reserve. RESULTS: Forty-five participants (32%) developed delirium. Greater participation in cognitive activity was associated with lower incidence (odds ratio = 0.92 corresponding to increase of 1 activity per week, 95% confidence interval (CI) = 0.86-0.98, P = .006) and severity (B = -0.06, 95% CI = -0.11 to -0.01, P = .02) of delirium after adjustment for age, sex, medical illnesses, and baseline cognition. Greater literacy was not associated with lower delirium incidence or severity. Of individual leisure activities, reading books, using electronic mail, singing, and computer games were associated with lower dementia incidence and severity. CONCLUSION: Greater late-life cognitive reserve was associated with lower delirium incidence and severity in older adults undergoing surgery. Interventions to enhance cognitive reserve by initiating or increasing participation in cognitive activities may be explored as a delirium prophylaxis strategy.

Nonsurgical Treatment of Aseptic Periprosthetic Gout Flare of the Knee: A Report of 2 Cases.

CASE: Gout is a rarely reported cause of a painful knee following total knee arthroplasty, but it can mimic infection in its symptomatology and workup. Two individuals who had previously undergone a knee replacement and had a history of gout had symptoms of infection. These patients presented with knee warmth and effusion, and they had elevated inflammatory markers and synovial cell counts. In both cases, there was a good response to medication, and surgery was avoided. CONCLUSION: Although simultaneous infection can occur, aseptic periprosthetic gout should be considered in individuals with a known history of gout, in those with a good response to anti-gout medication, and when there is an otherwise negative workup for infection.

Knee arthrotomy closure with barbed suture in flexion versus extension: a porcine study.

The purpose of this biomechanical study was to evaluate knee arthrotomy closure with a barbed suture in flexion versus extension. 48 porcine knees were randomized into three groups: full extension, 30° flexion, and 60° flexion. Each knee was then flexed to 90° and then 120°, with failures recorded. Arthrotomy closure in extension had significantly higher failure rates (6/16) upon flexion to 90° compared to arthrotomy closure in either 30° or 60° flexion (0/32) (P = 0.032). Upon ranging from 0° to 120°, arthrotomy failure occurred in 50% (8/16) of arthrotomies in the extension group, 6.25% (1/16) in the 30° flexion group and 18.75% (3/16) in the 60° flexion group (P = 0.022). Knee arthrotomy closure in extension compared to flexion had significantly higher rates of failure.

Infection rate following total joint arthroplasty in the HIV population.

The purpose of this study is to review a large series of HIV-infected patients who underwent total joint arthroplasty and identify potential risk-factors for infection. Sixty-nine HIV-infected arthroplasty cases were analyzed with 138 matched controls. Deep infection rate following total hip or knee arthroplasty was 4.4% (3 of 69) among HIV cases compared to 0.72% (1 of 138) among controls, yielding a non-significant 6.22 times increased odds of infection (95% CI 0.64-61.0, P=0.11). Kaplan-Meier survival curves for infection free survival and revision free survival revealed non-significantly decreased survival in HIV cases compared to controls (P=0.06 and P=0.09). Our results suggest that the rate of early joint infection following primary total joint arthroplasty in the HIV-infected population is lower than reported in a number of previously published studies.

The use of dermabond® as an adjunct to wound closure after total knee arthroplasty: examining immediate post-operative wound drainage.

Wound drainage after total knee arthroplasty (TKA) can be detrimental to surgical outcome. This IRB-approved randomized, prospective, blinded study examined the use of Dermabond® as an adjunct to wound closure after TKA. We proposed that Dermabond® supplementation to wound closure would result in a significant decrease in wound drainage after TKA. After standardized closure, patients were randomized into experimental or control groups with the experimental group receiving Dermabond® supplementation. Standardized dressings were evaluated postoperatively and drainage units were compared using a Mann-Whitney U Test. The median drainage for the Dermabond group (153) was lower than the drainage for the control group (657) at a statistically significant level (P<0.001).

Correcting fixed varus deformity with flexion contracture during total knee arthroplasty: the "inside-out" technique: AAOS exhibit selection.

BACKGROUND: Traditional methods for correcting a severe varus and flexion deformity of the knee during total knee arthroplasty can often lead to excessive release of the medial collateral ligament, hematoma formation, and reliance on constrained implants. The "inside-out" technique for correction of varus deformities involves performing a posteromedial capsulotomy at the level of the tibial cut and incising the superficial medial collateral ligament in a pie-crust manner in extension followed by serial manipulations with valgus stress. Our hypothesis was that this technique effectively corrects severe knee varus and flexion deformity with a reduced risk of complications. METHODS: Thirty-one consecutive patients (thirty-four knees) with a severe fixed varus and flexion deformity (varus alignment of ≥ 15° and flexion contracture of ≥ 5°) underwent total knee arthroplasty with use of the inside-out technique between October 2006 and December 2009. Physical examination, radiographs, and multiple outcome instruments were used to evaluate the results. RESULTS: The mean duration of follow-up was 3.1 ± 1.1 years (range, 1.7 to 4.9 years). There were no cases of hematoma formation, excessive release of the medial collateral ligament, or acute or delayed instability. A semi-constrained TC3 implant was used in two cases. The mean preoperative coronal alignment was 21.1° ± 4° of varus, which was corrected to 4.5° ± 1.6° of valgus after surgery. The mean preoperative flexion contracture was 10° ± 3.5°. Postoperatively, two patients (three knees) had a residual flexion contracture, which was ≤5° in all cases. The mean range of knee motion improved from 103.3° ± 14.1° preoperatively to 119.1° ± 8° at the time of final follow-up. The mean Knee Society Score pain subscore improved from 39.5 ± 12.6 to 93.2 ± 10.5, and the function subscore improved from 47.1 ± 17.8 to 78.5 ± 21.9. There was no evidence of implant loosening or osteolysis on radiographs. CONCLUSIONS: The technique described was safe, reproducible, and effective in treating combined varus and flexion deformity of the knee during total knee arthroplasty. It reduced the risks of over-release of the medial collateral ligament, hematoma formation, and the need for constrained implants.

The squeaking hip: a phenomenon of ceramic-on-ceramic total hip arthroplasty.

BACKGROUND: Early reports on modern ceramic-on-ceramic total hip replacements have demonstrated excellent clinical and radiographic results with few cases of catastrophic failure, which, in the case of earlier designs, often had been caused by implant fracture. Several reports, however, have noted the presence of audible squeaking. The purpose of the present study was to determine the incidence of squeaking in association with the use of this bearing couple. METHODS: During the period from March 2003 to May 2005, three surgeons performed 159 total hip arthroplasties in 143 patients with use of a ceramic-on-ceramic bearing. One hundred and forty-nine hips (131 patients) were available for review after at least one year of follow-up. These patients were followed prospectively with use of the modified Hospital for Special Surgery hip score and a patient-administered questionnaire. Additionally, a control group of sixty hips (forty-eight patients) with a metal-on-polyethylene bearing was matched to the ceramic group on the basis of age, sex, and body mass index to compare the incidence of squeaking and other noises. Radiographic evaluations were performed according to previously established criteria. RESULTS: Fourteen (10.7%) of 131 patients described an audible squeak during normal activities. However, squeaking was reproducible clinically in only four patients, and only one patient complained of squeaking before being presented with the questionnaire. The average Hospital for Special Surgery score improved from 19.8 preoperatively to 38.4 at the time of the latest follow-up, indicating excellent clinical results. Ninety-five percent of the patients had a satisfaction score of > or =8 of 10. Three hips dislocated. One of those three hips squeaked and was revised because of recurrent dislocations. One patient was considering revision because of squeaking. In the matched metal-on-polyethylene cohort, there were no cases of squeaking. CONCLUSIONS: The squeaking hip is a phenomenon that is unique to total hip replacements with hard-on-hard bearings. The incidence of squeaking in association with ceramic-on-ceramic bearings may be higher than previously reported as <1% of the patients in the present study reported this finding before being queried. The causes and implications of squeaking are yet to be determined. The use of hard-on-hard bearings offers many advantages in terms of wear reduction, especially for young and active patients. Nonetheless, patients considering ceramic-on-ceramic bearings should be counseled with regard to this phenomenon.

Multimodal pain management after total hip and knee arthroplasty at the Ranawat Orthopaedic Center.

UNLABELLED: Improvements in pain management techniques in the last decade have had a major impact on the practice of total hip and knee arthroplasty (THA and TKA). Although there are a number of treatment options for postoperative pain, a gold standard has not been established. However, there appears to be a shift towards multimodal approaches using regional anesthesia to minimize narcotic consumption and to avoid narcotic-related side effects. Over the last 10 years, we have used intravenous patient-controlled analgesia (PCA), femoral nerve block (FNB), and continuous epidural infusions for 24 and 48 hours with and without FNB. Unfortunately, all of these techniques had shortcomings, not the least of which was suboptimal pain control and unwanted side effects. Our practice has currently evolved to using a multimodal protocol that emphasizes local periarticular injections while minimizing the use of parenteral narcotics. Multimodal protocols after THA and TKA have been a substantial advance; they provide better pain control and patient satisfaction, lower overall narcotic consumption, reduce hospital stay, and improve function while minimizing complications. Although no pain protocol is ideal, it is clear that patients should have optimum pain control after TKA and THA for enhanced satisfaction and function. LEVEL OF EVIDENCE: Level V, expert opinion. See the Guidelines for Authors for a complete description of levels of evidence.