Purpose The goal of this study is to compare the cartilage of anterior cruciate ligament (ACL)‐reconstructed and uninjured contralateral knees using T1ρ MRI 12–16 months after ACL reconstructions. Methods Eighteen patients with ACL‐reconstructed knees (10 women, 8 men, mean age = 38.3 ± 7.8 years) were studied using 3T MRI. Injured and contralateral knee MR studies were acquired 12–16 months post‐operatively. Cartilage sub‐compartment T1ρ values of each injured knee were compared with the contralateral knee's values. Subgroup analysis of sub‐compartment T1ρ values in both knees was performed between patients with and without meniscal tears at the time of ACL reconstruction using a paired Student's t test. Results In ACL‐injured knees, the T1ρ values of the medial tibia (MT) and medial femoral condyle (MFC) were significantly elevated at 12–16 months follow‐up compared to contralateral knees. Patients with a medial meniscal tear had higher MFC and MT T1ρ values compared to respective regions in contralateral knees. Patients with lateral meniscal tears had higher lateral femoral condyle and LT T1ρ values compared to respective regions in contralateral knees. There were no differences between the injured and contralateral knees of patients without meniscal tears. Conclusions T1ρ MRI can detect significant changes in the medial compartments’ cartilage matrix of ACL‐reconstructed knees at 1 year post‐operatively compared to contralateral knees. The presence of a meniscal tear at the time of ACL reconstruction is a risk factor for cartilage matrix degeneration in the femorotibial compartments on the same side as the meniscal tear.

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Purpose Altered kinematics following ACL-reconstruction may be a cause of post-traumatic osteoarthritis. T1ρ MRI is a technique that detects early cartilage matrix degeneration. Our study aimed to evaluate kinematics following ACL-reconstruction, cartilage health (using T1ρ MRI), and assess whether altered kinematics following ACL-reconstruction are associated with early cartilage degeneration. Methods Eleven patients (average age: 33±9 years) underwent 3T MRI 18±5 months following ACL-reconstruction. Images were obtained at extension and 30° flexion under simulated loading (125 N). Tibial rotation (TR) and anterior tibial translation (ATT) between flexion and extension, and T1ρ relaxation times of the knee cartilage were analyzed. Cartilage was divided into five compartments: medial and lateral femoral condyles (MFC/LFC), medial and lateral tibias (MT/LT), and patella. A sub-analysis of the femoral weight-bearing (wb) regions was also performed. Patients were categorized as having “abnormal” or “restored” ATT and TR, and T1ρ percentage increase was compared between these two groups of patients. Results As a group, there were no significant differences between ACL-reconstructed and contralateral knee kinematics, however, there were individual variations. T1ρ relaxation times of the MFC and MFC-wb region were elevated (p≤0.05) in the ACL-reconstructed knees compared to the uninjured contralateral knees. There were increases (p≤0.05) in the MFC-wb, MT, patella and overall average cartilage T1ρ values of the “abnormal” ATT group compared to “restored” ATT group. The percentage increase in the T1ρ relaxation time in the MFC-wb cartilage approached significance (p=0.08) in the “abnormal” versus “restored” TR patients. Conclusions Abnormal kinematics following ACL-reconstruction appears to lead to cartilage degeneration, particularly in the medial compartment.

Objective To evaluate the association of exercise and knee-bending activities with magnetic resonance (MR)-based knee cartilage T2 relaxation times and morphologic abnormalities in asymptomatic subjects with and without osteoarthritis (OA) risk factors from the Osteoarthritis Initiative. Methods We studied 128 subjects with knee OA risk factors and 33 normal controls aged 45–55 years, with a body mass index of 18–27 kg/m2, and no knee pain. Subjects were categorized by exercise level, using the leisure activity component of the Physical Activity Scale for the Elderly, and by self-reported frequent knee-bending activities. Two radiologists graded the cartilage using the Whole Organ MR Imaging Score (WORMS) of right knee MR images. Cartilage was segmented and compartment specific T2 values were calculated. Statistical significance between the exercise groups and knee-bending groups was determined using multiple linear and logistic regression models. Results Among subjects with risk factors, light exercisers had lower T2 measurements than sedentary and moderate-strenuous exercisers (p=0.001); in women, moderate-strenuous exercise was associated with higher T2 values (p=0.001). Subjects without risk factors displayed no significant differences in T2 values by exercise. However, frequent knee-bending activities were associated with higher T2 values in both groups (p<0.02) and more severe cartilage lesions in the group with risk factors (p<0.001). Conclusions In subjects at risk for OA, light exercise was associated with low T2 measurements, whereas moderate-strenuous exercise in women was associated with high T2 values. Higher T2 values and WORMS grades were also found in frequent knee-benders and suggest greater cartilage degeneration in these individuals.

Perioperative blood loss during total knee arthroplasty can be significant, with magnitudes typically ranging from 300 mL to 1 L, with occasional reports of up to 2 L. The resultant anemia can lead to severe complications, such as higher rates of postoperative infection, slower physical recovery, increased length of hospital stay, and increased morbidity and mortality. Although blood transfusions are now screened to a greater extent than in the past, they still carry the inherent risks of clerical error, infection, and immunologic reactions, all of which drive the need to develop alternative blood management strategies. Thorough patient evaluation is essential to individualize care through dedicated blood management and conservation pathways in order to maximize efficacy and avoid associated complications. Interventions may be implemented preoperatively, intraoperatively, and postoperatively.