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Objectives: Excellent knee stability is necessary to achieve good postoperative clinical results in anterior cruciate ligament (ACL) reconstruction. However, there is little evidence in the literature regarding hamstring graft choice for ACL reconstruction. Our study intended to debate the best autograft choice for this procedure. We aimed to examine the functional and biomechanical outcomes of three different autografts used in ACL reconstruction, namely, Semitendinosus and Gracilis quadrupled (STGR) autograft, tripled or quadrupled ST autograft, and tripled Gracilis tendon autograft (GR). Methods: We conducted an observational, comparative, prospective cohort on 248 ACL reconstructed patients spanning 2 years (2009–2010) and evaluated the primary outcome with KT-1000 knee arthrometer and secondary outcomes with International Knee Documentation Committee (IKDC), Tegner ctivity cale, and Lysholm score. Results: The data suggest a statistically significant increase in IKDC score and Lysholm score in the GR group – standing for better subjective outcomes like pain – compared to the STGR and ST groups (P = 0.0018 and P = 0.0034, respectively) and statistically non-significant differences between the STGR and ST groups for all evaluated parameters. KT-1000 side-to-side evaluation demonstrates that STGR autograft offers less structural knee laxity compared to GR autograft in ACL reconstruction (P = 0.044). Conclusion: The study found that STGR autograft offers more stability to the knee compared to the GR autograft alone yet is associated with inferior subjective outcomes compared to the GR group. GR autograft is a valid substitute for ACL reconstruction, especially in patients presenting with hyperlaxity or demanding lower functional performance.

A bioresorbable, mono-crystalline magnesium (Mg) ring device and suture implantation technique were designed to connect the ends of a transected anterior cruciate ligament (ACL) to restabilize the knee and load the ACL to prevent disuse atrophy of its insertion sites and facilitate its healing. To test its application, cadaveric goat stifle joints were evaluated using a robotic/universal force-moment sensor testing system in three states: Intact, ACL-deficient, and after Mg ring repair, at 30°, 60°, and 90° of joint flexion. Under a 67-N anterior tibial load simulating that used in clinical examinations, the corresponding anterior tibial translation (ATT) and in-situ forces in the ACL and medial meniscus for 0 and 100 N of axial compression were obtained and compared with a control group treated with suture repair. In all cases, Mg ring repair reduced the ATT by over 50% compared to the ACL-deficient joint, and in-situ forces in the ACL and medial meniscus were restored to near normal levels, showing significant improvement over suture repair. These findings suggest that Mg ring repair could successfully stabilize the joint and load the ACL immediately after surgery, laying the framework for future in vivo studies to assess its utility for ACL healing. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2001-2008, 2016.

A bioresorbable, mono-crystalline magnesium (Mg) ring device and suture implantation technique were designed to connect the ends of a transected anterior cruciate ligament (ACL) to restabilize the knee and load the ACL to prevent disuse atrophy of its insertion sites and facilitate its healing. To test its application, cadaveric goat stifle joints were evaluated using a robotic/universal force-moment sensor testing system in three states: Intact, ACL-deficient, and after Mg ring repair, at 30°, 60°, and 90° of joint flexion. Under a 67-N anterior tibial load simulating that used in clinical examinations, the corresponding anterior tibial translation (ATT) and in-situ forces in the ACL and medial meniscus for 0 and 100 N of axial compression were obtained and compared with a control group treated with suture repair. In all cases, Mg ring repair reduced the ATT by over 50% compared to the ACL-deficient joint, and in-situ forces in the ACL and medial meniscus were restored to near normal levels, showing significant improvement over suture repair. These findings suggest that Mg ring repair could successfully stabilize the joint and load the ACL immediately after surgery, laying the framework for future in vivo studies to assess its utility for ACL healing. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2001-2008, 2016.

The insertions of ligaments and tendons to bone are morphologically and biomechanically complex. Within a short distance, the insertion (“enthesis”) is transformed from soft connective tissue to hard bone. In this chapter, we discuss the anatomy of the enthesis, including a review of the gross morphology as well as histology and appearance of two distinct types of insertions: the direct and indirect insertions to bone. The biomechanical function of insertion sites is then presented, including some challenges with methods involved in determining their properties. We then review the changes that occur across the insertion site during growth and skeletal maturity, using the femur-MCL-tibia complex as an example. The negative effects of immobilization on the insertion and its slow recovery following remobilization, together with positive effects of exercise, will then be presented.