ACL Tear

The overall aim of this multicenter RCT is to determine whether concomitant ALL reconstruction in children undergoing and ACL reconstruction will longitudinally result in a lower rate of graft failure than ACL reconstruction alone.

The goal of this prospective, cross-sectional study is to test the strength of the soleus muscle in participants who have a ACL tear confirmed by MRI. Previous studies have shown that the soleus muscle, which one of the muscles situated in the calf, decreases mechanical loading on the ACL. Therefore, we aim to test soleus muscle strength using a seated plantar flexor test. The main questions we aim to answer are: * Do patients with ACL tears demonstrate inter-limb soleus strength asymmetry (\>10%) * Do patients with ACL tears have soleus muscle weakness compared with uninjured (normative) participants? * Do changes in soleus strength values correlate with patient reported outcomes and stability, as measured by the IKDC questionnaire? To achieve this the VALD force frame will be used as the testing device for plantar flexor strength testing. This device records the force generated by the movement. This will be repeated three times on each leg as part of the testing procedure. Furthermore, as part of the testing procedure participants will be required to fill out an IKDC form to assess their knee stability. Interrater reliability of the force frame will be investigated. Further data from participants without ACL tears will be used to compare results. Thus allowing us to see if people with ACL tears have a weakness in the soleus muscle.

The purpose of this study is to investigate the effects of quadriceps focused interventions on knee function and biomechanics in adolescent patients with anterior cruciate ligament reconstruction (ACLR)

Currently the diagnosis of OA is based on radiographs and clinical findings, which is limited to detecting late-stage disease. There is a pressing, unmet clinical need for robust assessment of early changes in cartilage health. Towards this goal, extensive efforts are ongoing to develop quantitative MRI for cartilage matrix analysis. MR T1ρ and T2 relaxation times have shown to be promising imaging biomarkers for early cartilage degeneration and prediction of disease progression. However, many challenges remain to clinically applying these techniques, including lack of standardized acquisition and quantification methods, and long acquisition times. The study aims to develop novel, fast and reproducible MR T1ρ and T2 relaxation time imaging methods on MR systems from multiple vendors and establish a platform for standardization and cross validation of these measures as a tool for clinical trials using such techniques. Following method validation, patients at risk for osteoarthritis will be tested.

There is no consensus regarding the best surgical management of primary ACL tears. Recent evidence suggests that internal brace augmentation may increase load failure and therefore stabilize the graft in-situ at the time of ACL reconstruction. This prospective randomized controlled trial aims to compare the time to return to activity, and participant reported outcomes in participants with bone-tendon-bone ACL reconstruction with and without (control) internal brace augmentation.

The aim of this study is to investigate the efficacy of blood flow restriction (BFR) therapy in post-operative rehabilitation following knee arthroscopy for primary ACL reconstruction. BFR has been shown to effect time to return to activity and strength postoperatively. This study aims to analyze the effects of BFR therapy in patients who underwent primary ACL reconstruction surgery compared to controls. Participants will be randomized into either a treatment (BFR Cuff) or control (no BFR cuff) group. All participants will follow standard of care (SOC) physical therapy protocol for 12 weeks after surgery according to their treatment group. Strength and patient outcome measures will be recorded throughout the 2 year study period.

This study is being done to find out if metformin is effective at reducing pain by delaying the onset of post-traumatic osteoarthritis (PTOA) after anterior cruciate ligament (ACL) reconstruction. This research study will compare metformin to placebo. The placebo tablet looks exactly like metformin, but contains no metformin. Placebos are used in research studies to see if the results are due to the study drug or due to other reasons. Metformin is approved by the U.S. Food and Drug Administration (FDA) to treat type II diabetes. Notably, it also has anti-inflammatory effects, suggesting it could benefit people who have an ACL injury and are undergoing ACL reconstruction.

Our research is to evaluate the position and length of femoral tunnel, and to examine whether knee stability and clinical functional outcomes are better while using two-portal or three-portal technique .

The goal of this observational study is to explore the significance of subject-reported outcomes and clinical parameters in relation to the occurence of prolonged presence of arthrogenic muscle responses (AMR) in anterior cruciate ligament (ACL) reconstructed patients. The main questions it aims to answer are: 1\. Is there a link between the long-term occurence of AMR in ACL reconstructed patients and the level of kinesiophobia experienced before or after their ACL surgery? We hypothesize that ACL patients with higher levels of kinesiophobia are more likely to exhibit prolonged AMR as an unconscious reaction to protect their affected knee joint. 2\. Is the long-term presence of AMR in ACL reconstructed patients linked to their subjective knee function and stability (at certain time points throughout their recovery)? Our hypothesis is that poorer subjective knee function and stability might be associated with the presence of prolonged arthrogenic muscle responses in ACL reconstructed patients. 3\. Is the prolonged presence of AMR in ACL reconstructed patients linked to their pain levels (at certain time points throughout their recovery)? Our hypothesis is that ACL patients with higher pre- and/or postsurgical pain levels may exhibit a higher degree of long-lasting AMR. 4\. Is the long-term presence of AMR in ACL reconstructed patients linked to clinical parameters such as swelling, isometric quadriceps and hamstrings strength and knee range of motion (at certain time points throughout their recovery)? Our hypothesis is that ACL patients with poorer outcomes in terms of these clinical parameters may be more likely to exhibit prolonged AMR. Participants will: * Fill in the following questionnaires 1 week before surgery and at 1 and 3 months after surgery: * Demopgraphical information * Knee Injury and Osteoarthritis Outcome Score (KOOS) * Lysholm Score (only question 1) * Tegner Activity Scale (current activity level, pre-injury activity level and desired activity level after recovery) * Numeric Rating Score (NRS) for pain levels during the day \& during the night * ACL-Return to Sport after Injury Scale (ACL-RSI) * Complete a testing protocol 5 months after their surgery, which includes bilateral electromyographical measurements of the hamstrings and quadriceps during jumping tasks and a quadriceps inhibition measurement using the interpolated twitch method to evaluate the presence of prolonged AMR.

Anterior cruciate ligament repair (ACL) surgery presents moderate to severe pain during the inmediate postoperative period and the first days after surgery. In addition, due to the interest of surgeons and patients for early reinstatement, the use of blockages that decrease the strength of the quadriceps is avoided. Therefore, in recent years, the adductor canal block (ACB) has been used for postoperative analgesia with variable results. Genicular nerve block (GNB) has been used for pain management in patients with knee osteoarthritis and recently in knee arthroplasty surgery with results similar to the local anesthetic infiltration techniques by the surgeon (LIA). Considering their good results in these patients in addition to being a 100% sensitive block without risk of motor involvement. The investigators proposed this experimental study to evaluate tha analgesic efficacy of the genicular nerve block (GNB) compared with the adductor canal block (ACB) for the Anterior cruciate ligament (ACL) repair surgery.