Effect of voluntary soft tissue tension and articular conformity after total knee arthroplasty on in vivo anteroposterior displacement.

The in vivo relationship between the degree of voluntary soft tissue tension and articular conformity after total knee arthroplasty (TKA) and anteroposterior (AP) displacement was simultaneously investigated by analyzing LCS prostheses (posterior cruciate ligament-sacrificing rotating platform design) in 20 knees from 20 patients. AP displacement was measured using the KT-2000 arthrometer, at 30° and 75° flexion, while patients were conscious and under anesthesia; 30° flexion was regarded as high conformity and 75° as low conformity. Mean displacements at 30° and 75° were 5.1mm and 7.0mm, respectively, in conscious patients, and 6.7 mm and 7.7 mm, respectively, in patients under anesthesia. AP displacement was significantly associated with soft tissue tension (p=0.026) and conformity (p=0.001). No interaction was observed between the two variables (p=0.193). Surgeons should recognize that AP displacement is greater in anesthetized patients than in conscious patients, regardless of the degree of conformity, and that higher conformity shows less displacement, regardless of the degree of soft tissue tension. These results may help surgeons to determine the intra-operative AP displacement required for proper postoperative displacement in the current prosthetic design.

Protective mechanism of ultrafiltration against cardiopulmonary bypass-induced lung injury.

BACKGROUND: We previously demonstrated a negative effect of cardiopulmonary bypass (CPB) in a canine model of single-lung graft function and an improved effect with ultrafiltration during CPB. OBJECTIVE: To investigate the mechanism of these effects, focusing on cytokines and pulmonary surfactants using real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). MATERIALS AND METHODS: Fifteen left-sided single-lung transplant procedures were performed in pairs of dogs. The animals were divided into 3 groups. In one group, transplantation was performed without CPB (non-CPB group); in a second group, transplantation was performed with CPB and CPB flow was decreased slowly and pulmonary artery pressure was controlled (CPB group; and in the third group, transplantation was performed with CPB and ultrafiltration (CPB+UF group). Grafted lung specimens were harvested for RT-PCR of cytokines (IL-6, IL-8, and IL-10) and surfactant proteins (SP-A, SP-B, and SP-C). RESULTS: Real-time quantitative RT-PCR demonstrated increased IL-6 expression in the CPB group compared with the non-CPB group. IL-6 gene expression was suppressed and pulmonary surfactant restored using ultrafiltration. Gene expression of surfactant protein (SP)-A, SP-B, and SP-C was decreased in the CPB group compared with normal lung and ultrafiltration groups, which demonstrated sustained gene expression of SP-A and SP-B. CONCLUSION: Cardiopulmonary bypass has negative effects on grafts; however, ultrafiltration attenuates acute lung dysfunction by decreasing the inflammatory response and increasing pulmonary surfactant.

Economic impact of extended treatment with peginterferon alpha-2a and ribavirin for slow hepatitis C virologic responders.

It is difficult to achieve a sustained virologic response from antiviral therapy for genotype 1 hepatitis C virus-infected patients without a sufficient virologic response in the early weeks after treatment. However, a recent study has reported on the effectiveness of an extended course of treatment with peginterferon alpha-2a plus ribavirin for slow virologic responders. The aim of this study was to evaluate the economic impact of an extended course of treatment. A Markov cohort model of hepatitis C was designed in order to demonstrate the clinical states, based on the assigned transition probabilities over 30 years. The slow virologic responders treated with an extended 72-week course of therapy could increase by 0.55 the quality-adjusted life years (=15.35-14.80) and reduce the lifetime cost by $2762 (=71 559-69 438) in comparison with those treated by the standard 48-week course. One-way sensitivity analyses did not change the cost-effectiveness. Therefore, the extended 72 weeks of treatment with peginterferon alpha-2a plus ribavirin for slow virologic responders could be cost-effective in comparison with the standard 48 weeks of treatment.