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Background: The optimal treatment strategy for patients with an anterior cruciate ligament (ACL) rupture is still under debate. Different determinants of the need for a reconstruction have not been thoroughly investigated before. Purpose: To investigate why, when, and which patients with an ACL rupture who initially started with rehabilitation therapy required reconstructive surgery. Study Design: Case-control study; Level of evidence, 3. Methods: In the Conservative versus Operative Methods for Patients with ACL Rupture Evaluation (COMPARE) trial, 167 patients with an ACL rupture were randomized to early ACL reconstruction or rehabilitation therapy plus optional delayed ACL reconstruction. We conducted an exploratory analysis of a subgroup of 82 patients from this trial who were randomized to rehabilitation therapy plus optional delayed ACL reconstruction. The reasons for surgery were registered for the patients who underwent a delayed ACL reconstruction. For these patients, we used the International Knee Documentation Committee (IKDC) subjective knee form, Numeric Rating Scale for pain, and instability question from the Lysholm questionnaire before surgery. To determine between-group differences between the nonoperative treatment and delayed ACL reconstruction group, IKDC and pain scores during follow-up were determined using mixed models and adjusted for sex, age, and body mass index. Results: During the 2-year follow-up of the trial, 41 of the 82 patients received a delayed ACL reconstruction after a median time of 6.4 months after inclusion (interquartile range, 3.9-10.3 months). Most reconstructions occurred between 3 and 6 months after inclusion (n = 17; 41.5%). Ninety percent of the patients (n = 37) reported knee instability concerns as a reason for surgery at the moment of planning surgery. Of these patients, 18 had an IKDC score ≤60, 29 had a pain score of ≥3, and 33 patients had knee instability concerns according to the Lysholm questionnaire before surgery. During follow-up, IKDC scores were lower and pain scores were higher in the delayed reconstruction group compared with the nonoperative treatment group. Patients in the delayed reconstruction group had a significantly younger age (27.4 vs 35.3 years; P =.001) and higher preinjury activity level compared with patients in the nonoperative treatment group. Conclusion: Patients who experienced instability concerns, had pain during activity, and had a low perception of their knee function had unsuccessful nonoperative treatment. Most patients received a delayed ACL reconstruction after 3 to 6 months of rehabilitation therapy. At baseline, patients who required reconstructive surgery had a younger age and higher preinjury activity level compared with patients who did not undergo reconstruction. [ABSTRACT FROM AUTHOR]

Background: Anterior cruciate ligament (ACL) rupture is a well-known risk factor for development of knee osteoarthritis. Early identification of those patients at risk and early identification of the process of ACL rupture leading to osteoarthritis may aid in preventing the onset or progression of osteoarthritis. Purpose: To identify early degenerative changes as assessed on magnetic resonance imaging (MRI) after 2-year follow-up in patients with a recent ACL rupture and to evaluate which determinants are related to these changes. Study Design: Cohort study; Level of evidence, 2. Methods: Included in this study were 154 adults aged between 18 and 45 years with acute ACL rupture diagnosed by physical examination and MRI, without previous knee trauma or surgery, and without osteoarthritic changes on radiographs. A total of 143 patients completed the 2-year follow-up, and the results in this study apply to these 143 patients. All patients were treated according to the Dutch guideline on ACL injury. Of the 143 patients, 50 patients were treated nonoperatively during the 2-year follow-up period. Main outcome was early degenerative changes assessed on MRI defined as progression of cartilage defects and osteophytes in tibiofemoral and patellofemoral compartments. Patient characteristics, activity level, functional instability, treatment type, and trauma-related variables were evaluated as determinants. Results: The median time between MRI at baseline and MRI at 2-year follow-up was 25.9 months (interquartile range, 24.7-26.9 months). Progression of cartilage defects in the medial and lateral tibiofemoral compartments was present in 12% and 27% of patients, and progression of osteophytes in tibiofemoral and patellofemoral compartments was present in 10% and 8% of patients, respectively. The following determinants were positively significantly associated with early degenerative changes: male sex (odds ratio [OR], 4.43; 95% CI, 1.43-13.66; P = .010), cartilage defect in the medial tibiofemoral compartment at baseline (OR, 3.66; 95% CI, 1.04-12.95; P = .044), presence of bone marrow lesions in the medial tibiofemoral compartment 1 year after trauma (OR, 5.19; 95% CI, 1.56-17.25; P = .007), joint effusion 1 year after trauma (OR, 4.19; 95% CI, 1.05-16.72; P = .042), and presence of meniscal tears (OR, 6.37; 95% CI, 1.94-20.88; P = .002). When the patients were categorized into 3 treatment groups (nonoperative, reconstruction <6 months after ACL rupture, and reconstruction ≥6 months after ACL rupture), there was no significant relationship between the treatment options and the development of early degenerative changes. Conclusion: Two years after ACL rupture, early degenerative changes were assessed on MRI. Concomitant medial cartilage defect and meniscal injury, male sex, persistent bone marrow lesions in the medial tibiofemoral compartment, and joint effusion are risk factors for degenerative changes. [ABSTRACT FROM AUTHOR]

Background: Compressive and quadriceps forces have been associated with noncontact anterior cruciate ligament (ACL) injury. The purpose of this study was to quantify the relative importance of each load component during noncontact ACL injury.Hypothesis: We hypothesized that the introduction of a quadriceps force lowers the axial compressive force threshold to produce ACL injury.Study Design: Controlled laboratory study.Methods: Six pairs of fresh-frozen cadaveric knees, flexed to 15°, were loaded with axial compression (group A) or compression with a quadriceps force (group B) until failure. All specimens underwent axial compressive loading under displacement control with a time to peak load of 50 msec. The initial displacement of the MTS actuator was 8 mm and was increased in 2-mm increments with successive tests until catastrophic damage of the joint occurred. Failure was determined by a combination of clinical specimen examination and force-displacement data analysis and by dissection and direct visualization after failure was recognized. Differences in failure load between groups were examined using a paired t test (significance, P ≤ .05).Results: In group A, there were 2 isolated ACL injuries, 2 ACL ruptures combined with a tibial plateau fracture, and 2 isolated tibial plateau fractures. In group B, there were 5 isolated ACL ruptures and 1 tibial plateau fracture. There was a significant difference in the average failure load between groups A and B: 10 832 N (95% confidence interval [CI], 9743-11 604 N) and 6119 N (95% CI, 4335-7903 N), respectively.Conclusion: Isolated compressive forces displayed an ability to produce an ACL injury in this cadaveric model, but the addition of a quadriceps load significantly reduced the compressive force required for ACL injury.Clinical Relevance: Compressive and quadriceps forces contribute to noncontact ACL injury and should be taken into account when developing ACL injury prevention programs and rehabilitation after ACL reconstruction. [ABSTRACT FROM PUBLISHER]

Background: The knee is one of the most frequently injured joints, including 80 000 anterior cruciate ligament (ACL) tears in the United States each year. Bone bruises are seen in over 80% of patients with ACL injuries, and have been associated with an overt loss of cartilage overlying those regions within 6 months of injury. Hypothesis: The level of contact pressure developed in the human knee joint and the extent of articular cartilage and underlying subchondral bone injuries will depend on the mechanism of applied loads/moments during rupture of the ACL. Study Design: Controlled laboratory study. Methods: Seven knee pairs, flexed to 30°, were loaded in compression or internal torsion until injury. Pressure-sensitive film recorded the magnitude and location of contact. Histologic analysis and magnetic resonance imaging were used to document microtrauma to the tibial plateau cartilage and subchondral bone. Results: All specimens suffered ACL injury, either in the form of a midsubstance rupture or avulsion fracture. The contact area and pressures were higher for compression than torsion experiments. After being loaded, the articular cartilage in the central and posterior regions of the medial tibial plateau showed increased magnetic resonance imaging signal intensity, corresponding to an increased susceptibility to absorb water. Histologically, there were more microcracks in the subchondral bone and more articular cartilage damage in the compression than torsion experiments. Conclusion: Significant damage occurs to the articular cartilage and underlying subchondral bone during rupture of the ACL. The types and extent of these tissue injuries are a function of the mechanism of ACL rupture. Clinical Relevance: Patients suffering an ACL injury may be at risk of osteochondral damage, especially if the mechanism of injury involves a high compressive loading component, such as during a jump landing. [ABSTRACT FROM AUTHOR]