Anterior Cruciate Ligament Reconstruction Using a Ribbon-Like Graft With a C-Shaped Tibial Bone Tunnel

According to recent anatomic studies, the anterior cruciate ligament (ACL) appears to be a flat, “ribbon-like” structure, with a thin, oval-shaped insertion on the femur and a C-shaped tibial insertion. According to this anatomy, we describe an ACL-reconstruction technique that aims to approximate this natural anatomy. The basic principle of this technique is not to use conventional round tunnels but create tunnel shapes that resemble more closely the original ACL insertion sites. Using either a rectangular quadriceps tendon graft or a “flat” hamstring graft may not only provide a biomechanical advantage with increased rotational stability but also improve bone–tendon healing due to increased bone–tendon contact and decreased diffusion length. Creating a C-shaped tibial tunnel also avoids laceration of the anterior horn of the lateral meniscus, which is frequently harmed during conventional tibial tunnel drilling

Successful treatment of painful irreparable partial meniscal defects with a polyurethane scaffold: two-year safety and clinical outcomes

Background: A novel, biodegradable, polyurethane scaffold was designed to fulfill an unmet clinical need in the treatment of patients with painful irreparable partial meniscal defects. Hypothesis: The use of an acellular polyurethane scaffold for new tissue generation in irreparable partial meniscal defects provides both pain relief and improved functionality. Study Design: Case series; Level of evidence, 4. Methods: Fifty-two patients with irreparable partial meniscal defects (34 medial and 18 lateral, 88% with 1-3 previous surgeries on the index meniscus) were implanted with a polyurethane scaffold in a prospective, single-arm, multicenter, proof-of-principle study. Safety was assessed by the rate of scaffold-related serious adverse events (SAEs) and the International Cartilage Repair Society articular cartilage scoring system comparing magnetic resonance imaging (MRI) at 24 months to MRI at baseline (1 week). Kaplan-Meier time to treatment failure distributions were performed. Clinical outcomes were measured comparing visual analog scale, International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome Score (KOOS), and Lysholm scores at 24 months from baseline (entry into study). Results: Clinically and statistically significant improvements (P < .0001) compared with baseline were reported in all clinical outcome scores (baseline/24 months): visual analog scale (45.7/20.3), International Knee Documentation Committee (45.4/70.1), KOOS symptoms (64.6/78.3), KOOS pain (57.5/78.6), KOOS activities of daily living (68.8/84.2), KOOS sports (30.5/59.0), KOOS quality of life (33.9/56.6), and Lysholm (60.1/80.7), demonstrating improvements in both pain and function. The incidence of treatment failure was 9 (17.3%) patients, of which 3 patients (8.8%) had medial meniscal defects and 6 patients (33.3%) had lateral meniscal defects. There were 9 SAEs requiring reoperation. Stable or improved International Cartilage Repair Society cartilage grades were observed in 92.5% of patients between baseline and 24 months. Conclusion: At 2 years after implantation, safety and clinical outcome data from this study support the use of the polyurethane scaffold for the treatment of irreparable, painful, partial meniscal defects

Interobserver reliability of the international society of arthroscopy, knee surgery and orthopaedic sports medicine (ISAKOS) classification of meniscal tears

Background: Consistency of arthroscopic evaluation and documentation in meniscal tears between investigators is essential to the validity of multicenter studies. A group of experts developed a classification of meniscal tears that may be used internationally. Hypothesis: The International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification of meniscal tears provides sufficient interobserver reliability for pooling of data from international clinical trials designed to evaluate the outcomes of treatment for meniscal tears. Study Design: Cohort study (diagnosis); Level of evidence, 1. Methods: A pilot study was performed by having 8 members of the committee grade 10 arthroscopic videos for classification of tear depth, rim width, location, tear pattern, and quality of the tissue. The results of the pilot study were used to change the instruction sheet and evaluation form. International interobserver reliability was determined by having 8 orthopaedic surgeons who practice in different countries evaluate 37 arthroscopic videos selected to represent different meniscal tear characteristics. The Spearman rho correlation coefficient was used to compare the area of the meniscus excised, as drawn on the diagram, with the numeric percentage of meniscus excised. Results: There was an 87% agreement for anterior-posterior location of the tear (kappa=.65); 79% agreement for tear pattern (kappa=.72); 88% agreement for tear depth (kappa=.52); 68% agreement for anterior, middle, and posterior location of the tear (kappa=.46); and 72% agreement for tissue quality (kappa=.47). There was 54% agreement for the rim width (kappa=.25) and 67% agreement if the tear was central to the popliteal hiatus (kappa=.36). Based on the Landis and Koch criteria for kappa coefficients, there was substantial agreement for anterior-posterior location of the tear and tear pattern; moderate agreement for tear depth, anterior, middle, and posterior location of the tear, and tissue quality; and fair agreement for rim width and if the tear was central to the popliteal tear. Interobserver reliability based on the intraclass correlation coefficient (ICC) was good for tear length (ICC=.83) and moderate for percentage of meniscus that was excised (ICC=.65). The mean rho for all raters was .92 (95% confidence interval [CI],.89-.94) comparing the values for percentage of meniscus excised with the area on the diagrams. Conclusion: The ISAKOS classification of meniscal tears provides sufficient interobserver reliability for pooling of data from international clinical trials designed to evaluate the outcomes of treatment for meniscal tears

RECOGNITION PROBLEM OF FRONTAL SINGULARITIES

A natural class of mappings, frontal mappings, is explained from both geometric and algebraic aspects. Several results on the recognition of frontal singularities, in particular, cuspidal edges, folded umbrellas, swallowtails, Mond singularities, Shcherbak singularities, and their openings are surveyed