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The medial patellofemoral ligament (MPFL) is the primary static stabilizer to lateral translation of the patella and serves as part of the medial patellar soft tissue restraints. Because of the sensitivity of MPFL graft function after reconstruction to the position of the femoral tunnel, many studies have aimed to identify the exact point of the femoral origin, as well as defining techniques to confirm this position intraoperatively. We describe the ribbon-shaped footprint of the MPFL on the medial femur and the associated difficulty in identifying the origin as a single "point." Varying isometry and biomechanical functions have been shown to exist within the most proximal and most distal fibers, suggesting the function of the MPFL may not be fully recreated with a tubular graft in a round tunnel. We review the anatomical descriptions of the elongated femoral footprint of the MPFL and describe our surgical technique to recreate this. [ABSTRACT FROM AUTHOR]

Articular cartilage defects strongly predispose patients to developing early joint degeneration and osteoarthritis, but for more than 15 years, no new cartilage-repair technologies that we know of have been approved by the U.S. Food and Drug Administration. Many studies examining novel approaches to cartilage repair, including cell, tissue, or matrix-based techniques, have shown great promise, but completing randomized controlled trials (RCTs) to establish safety and efficacy has been challenging, providing a major barrier to bringing these innovations into clinical use. In this article, we review reasons that surgical innovations are not well-suited for testing through RCTs. We also discuss how analytical methods for reducing bias, such as propensity scoring, make prospective observational studies a potentially viable alternative for testing the safety and efficacy of cartilage-repair and other novel therapies, offering the real possibility of therapeutic innovation. [ABSTRACT FROM AUTHOR]

Background: There are limited treatment options for tissue restoration and the prevention of degenerative changes in the knee. Stem cells have been a focus of intense preclinical research into tissue regeneration but limited clinical investigation. In a randomized, double-blind, controlled study, the safety of the intra-articular injection of human mesenchymal stem cells into the knee, the ability of mesenchymal stem cells to promote meniscus regeneration following partial meniscectomy, and the effects of mesenchymal stem cells on osteoarthritic changes in the knee were investigated. Methods: A total of fifty-five patients at seven institutions underwent a partial medial meniscectomy. A single superolateral knee injection was given within seven to ten days after the meniscectomy. Patients were randomized to one of three treatment groups: Group A, in which patients received an injection of 50 × 106 allogeneic mesenchymal stem cells; Group B, 150 × 106 allogeneic mesenchymal stem cells; and the control group, a sodium hyaluronate (hyaluronic acid/ hyaluronan) vehicle control. Patients were followed to evaluate safety, meniscus regeneration, the overall condition of the knee joint, and clinical outcomes at intervals through two years. Evaluations included sequential magnetic resonance imaging (MRI). Results: No ectopic tissue formation or clinically important safety issues were identified. There was significantly increased meniscal volume (defined a priori as a 15% threshold) determined by quantitative MRI in 24% of patients in Group A and 6% in Group B at twelve months post meniscectomy (p = 0.022). No patients in the control group met the 15% threshold for increased meniscal volume. Patients with osteoarthritic changes who received mesenchymal stem cells experienced a significant reduction in pain compared with those who received the control, on the basis of visual analog scale assessments. Conclusions: There was evidence of meniscus regeneration and improvement in knee pain following treatment with allogeneic human mesenchymal stem cells. These results support the study of human mesenchymal stem cells for the apparent knee-tissue regeneration and protective effects. Level of Evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]