Development of a virtual reality arthroscopic knee simulator.

The virtual reality arthroscopic knee simulator (VR-AKS) consists of a computer platform, a video display, and two force-feedback (haptic) interfaces which also monitor the position of the instruments in the user's hands. The forces that the user would normally apply to the lower limb during arthroscopy are directed through an instrumented surrogate leg. Proprietary software furnishes the mathematical representation of the physical world and replicates the visual, mechanical, and behavioral aspects of the knee while task-oriented programs monitor and record specific areas of user performance. A prototype has demonstrated the feasibility of the system and work on the first, fully functional simulator will begin soon.

Treatment of articular cartilage defects of the knee with autologous chondrocyte implantation.

The treatment of focal full thickness articular defects in the knee has continued to present a challenge, with no traditional treatment method providing consistent acceptable long-term clinical results. Patients with significant chondral defects frequently have persistent joint line pain, swelling, and catching in the knee. In contrast to marrow stimulation treatment techniques, such as abrasion arthroplasty, drilling, or microfracture which populate the defect with pluripotential stem cells, the use of cultured autologous chondrocytes fills the defect with cells of a committed pathway to develop hyaline-like cartilage. This hyaline-like cartilage more closely recreates the wear characteristics and durability of normal hyaline cartilage than the fibrous or fibrocartilage repair tissue formed by pluripotential stem cells. The purpose of this paper is to review the efficacy of available treatment options as well as the basic science rationale, indications, technique, postoperative rehabilitation, and clinical results of using cultured autologous chondrocytes in the treatment of focal full thickness chondral defects of the knee.

Disruption of the anterior cruciate ligament in a 4-year-old child.

Anterior cruciate ligament (ACL) injuries in children are rare. Thus, the natural history of ACL injuries in skeletally immature patients is unknown. This case represents the longest follow-up (11 years) reported in the literature of an ACL injury in a child of less than 5 years old.

Anterior cruciate ligament reconstruction: evaluation with MR imaging.

Fifty magnetic resonance (MR) imaging examinations were performed in 37 patients after arthroscopic anterior cruciate ligament (ACL) reconstruction with patellar bone-tendon-tibial bone autografts. T1-weighted sagittal and axial images were obtained. In 34 patients with clinically stable ACL autografts, 43 of 47 MR examinations demonstrated a well-defined, intact ACL autograft. All three patients with ACL laxity failed to demonstrate a well-defined autograft, for an overall correlation between MR imaging and clinical examination results of 92%. Of the 12 patients who underwent second-look arthroscopy, 100% correlation was present between MR imaging and arthroscopic results. As in the nonreconstructed knee, buckling of the posterior cruciate ligament was suggestive of ACL laxity. MR imaging also documented optimum placement of bone tunnels in the femur and tibia. MR imaging has proved to be an excellent noninvasive imaging modality for evaluating ACL reconstruction, while also providing ancillary information about the postoperative knee.

Effect of model traumatic injury on hepatic drug-metabolizing enzymes.

Abdominal aorta ligation in rats was found to be a suitable model traumatic injury for the study of the effect of trauma on drug-metabolizing enzymes. This procedure was found to result in a rapid decrease in both cytochrome P-450 and mixed function amine oxidase activities. Recovery of mixed function amine oxidase activity was slower than recovery of cytochrome P-450 activity.