The role of the Rolimeter in quantifying knee instability compared to the functional outcome of ACL-reconstructed versus conservatively-treated knees.

The purpose of this study is to correlate the measurement of anterior knee laxity using the Rolimeter with the functional outcome of anterior cruciate ligament (ACL) deficient knees. We tested 29 patients (12 males/17 females) with an average age of 33 years (range 19-47) that had been treated for ACL rupture, either by reconstruction or conservatively. The average follow-up at time of testing was 33 months (range 6-67).Functional outcome was graded by means of a questionnaire based on the IKDC score, the sports activity rating scale (SARS), the Cincinnati knee-rating system and the activities of daily living (ADL) scale, and by two functional knee tests (the one-leg hop test and the cross-over hop test). The anterior knee laxity was measured for both knees with the Rolimeter, and the side-to-side difference was calculated. We have found no correlation between the joint laxity and the functional outcome score.(P>0.05). When we compared both groups, we found a significant, though very low, correlation between the laxity and the functional questionnaire for the reconstructed group. (r=0.51, P=0.036). Therefore, the joint laxity measurement does not necessarily reflect the functional outcome of ACL-deficient knees. An explanation can be found in the importance of the proprioception and neuromuscular control in compensating the ACL-deficient knee.

Development of an ex vivo model of pig kidney perfused with human lymphocytes. Analysis of xenogeneic cellular reactions.

BACKGROUND: Because of the explosive nature and the extremely rapid process of hyperacute rejection (HAR), significant infiltration of the xenograft by immunocompetent cells is not observed, and the role and the mechanism of action of cell-mediated rejection in discordant xenografts are therefore still under discussion. METHOD: We developed an experimental approach using pig kidneys perfused with human peripheral blood lymphocytes (PBL) in which the immunologic barrier of hyperacute rejection was excluded and which mimics the in vivo situation. RESULTS: PBL retention in the kidney was evaluated at 20-minute intervals for 3 hours. Retention increased from 30% to 80% with the time of perfusion and was specific because significantly fewer syngeneic lymphocytes were retained. Phenotype analysis of recovered PBL showed a significant decrease in natural killer (NK) cells. Immunohistochemical studies revealed the presence of NK cells and T lymphocytes in the glomerular and interstitial tubular structures of the kidney. Functional studies showed a progressive cessation of diuresis and augmentation of renal vascular resistance when the kidney was perfused with PBL. Electron microscopy examinations of kidney sections perfused with PBL showed swollen endothelial zones, suggesting alterations to and damage of the endothelium. CONCLUSIONS: This system provides a valuable model for the study of early discordant xenogeneic cellular rejection and demonstrates the predominance of xenograft infiltration by NK cells.