A comparison of patellofemoral cartilage morphology and deformation in anterior cruciate ligament deficient versus uninjured knees

Abstract

Anterior cruciate ligament (ACL) deficient patients have an increased rate of patellofemoral joint (PFJ) osteoarthritis (OA) as compared to the general population. Although the cause of post-injury OA is multi-factorial, alterations in joint biomechanics may predispose patients to cartilage degeneration. This study aimed to compare in vivo PFJ morphology and mechanics between ACL deficient and intact knees in subjects with unilateral ACL ruptures. Eight male subjects underwent baseline MRI scans of both knees. They then performed a series of 60 single-legged hops, followed by a post-exercise MRI scan. This process was repeated for the contralateral knee. The MR images were converted into three-dimensional surface models of cartilage and bone in order to assess cartilage thickness distributions and strain following exercise. Prior to exercise, patellar cartilage was significantly thicker in intact knees as compared to ACL deficient knees by 1.8%. In response to exercise, we observed average patellar cartilage strains of 5.4 ± 1.1% and 2.5 ± 1.4% in the ACL deficient and intact knees, respectively. Importantly, the magnitude of patellar cartilage strain in the ACL deficient knees was significantly higher than in the intact knees. However, while trochlear cartilage experienced a mean strain of 2.4 ± 1.6%, there was no difference in trochlear cartilage strain between the ACL deficient and uninjured knees. In summary, we found that ACL deficiency was associated with decreased patellar cartilage thickness and increased exercise-induced patellar cartilage strain when compared to the uninjured contralateral knees.

Activities of daily living influence tibial cartilage T1rho relaxation times

“…A randomly selected knee from each subject (2 left, 5 right) was imaged first thing in the morning (8 AM) and again in the afternoon (4 PM) (Coleman et al, 2013; Widmyer et al, 2013) using a 3.0T MR scanner (Trio Tim; Siemens Medical Solutions; Malvern, PA) and an eight-channel knee coil (Invivo; Gainesville, FL) (Carter et al, 2015; Taylor et al, 2013; Utturkar et al, 2013). Subjects were asked to refrain from any strenuous weight-bearing activities 12 hours prior to the morning imaging session, and each subject rested supine for 45 minutes immediately before the baseline MR scan to enable cartilage equilibration (Eckstein et al, 1999; Owusu-Akyaw et al, 2018; Sutter et al, 2014). In order to most directly capture the effects of activities of daily living on T1rho relaxation times, no rest period was provided prior to the afternoon imaging session.…”

In Vivo Assessment of Exercise-Induced Glenohumeral Cartilage Strain

“…This investigation quantified glenohumeral cartilage deformations in response to loaded exercise with previously validated MRI-based 3D solid modeling techniques. 8 , 9 , 15 , 16 , 24 , 29 , 32 Specifically, this study evaluated exercise-induced glenohumeral cartilage strain following a series of 30 push-ups. Compressive strains were measured in the glenoid (15%) and humeral head (17%) articular cartilage.…”

“…This method was previously validated and has been extensively used to quantify cartilage thickness in vivo in other joints. 8 , 9 , 15 , 16 , 24 , 29 , 32 Additionally, to ensure quality control, all segmentations were reviewed by a fellowship-trained musculoskeletal radiologist with 30 years of experience (C.E.S.). The bone and cartilage contours were then compiled to create a 3D surface mesh model of the humerus, the glenoid, and the respective cartilage surfaces (Geomagic Studio; Geomagic) ( Figure 1A ).…”

Editorial Commentary: Advances in 3-Dimensional Imaging are the Key to Improving our Surgical Precision in Hip Arthroscopy and Beyond

“…The double-echo steady-state sequence is like the previously described MERGE sequence in that it provides high-resolution contrast between bone and cartilaginous structures. 1,2,10 In their investigation, Schleich et al 9 found sensitivity, specificity, and accuracy of 98%, 76.2%, and 95.9%, respectively, for the detection of labral tears. A large part of what makes the study by Higashihira et al 4 unique, and ultimately compelling, is the description of labral tear frequency relative to acetabular location.…”