To compare 5-year change in femorotibial cartilage thickness in 121 young, active adults with an acute anterior cruciate ligament (ACL) tear randomized to a strategy of structured rehabilitation plus ...early ACL reconstruction (ACLR) or structured rehabilitation plus optional delayed ACLR.
62 patients were randomized to early ACLR, 59 to optional delayed ACLR. Magnetic resonance imaging (MRI) was acquired within 4 weeks of injury, at two- and 5-years follow-up. Main outcome was 5-year change in overall femorotibial cartilage thickness. Secondary outcomes included the location-independent cartilage ChangeScore, summarizing thinning and thickening in 16 femorotibial subregions. An exploratory as-treated comparison was performed additionally.
Baseline and at least one follow-up MRI were available for 117 patients. Over 5 years, a comparable increase in overall femorotibial cartilage thickness was observed for patients randomized to early ACLR (n = 59) and patients randomized to optional delayed ACLR (n = 58, adjusted mean difference: −5 μm, 95% CI: −118, 108μm). However, the location-independent cartilage ChangeScore was greater in those treated with early ACLR than in patients treated with optional delayed ACLR (adjusted mean difference: 403 μm 119, 687μm). As-treated analysis showed no between-group differences for the main outcome, while the location-independent cartilage ChangeScore was greater for patients treated with early (adjusted mean difference: 632 μm 268, 996μm) or delayed ACLR (adjusted mean difference: 449 μm 108, 791μm) than for patients treated with rehabilitation alone.
In young active adults with acute ACL-injury, choice of treatment strategy for the injured ACL did not modify the magnitude of 5-year change in overall femorotibial cartilage thickness.
ISRCTN84752559.
Objective
Anterior cruciate ligament (ACL) rupture involves an increased risk of osteoarthritis. The purpose of this study was to explore changes in cartilage thickness over 5 years after ACL ...rupture.
Methods
A total of 121 young active adults (ages 18–35 years; 26% women) from the Knee ACL, Nonsurgical versus Surgical Treatment (KANON) study, who had acute traumatic rupture of the ACL were studied. Sagittal magnetic resonance images were acquired within 4 weeks of ACL rupture (baseline) and at the 2‐year and 5‐year followup assessments. Medial and lateral femorotibial cartilage was segmented (with blinding to acquisition order), and the mean cartilage thickness was computed across 16 femorotibial subregions. Total femorotibial cartilage thickness change was the primary analytic focus. Maximal subregional mean cartilage thickness loss (ordered value 1 OV1) and gain (ordered value 16 OV16), independent of its specific location in individual knees, were the secondary analytic focus.
Results
Overall femorotibial cartilage thickness increased by 31 μm/year over 5 years (95% confidence interval 18, 44). The increase was similar in men and women and was significantly greater in those younger, as compared with those older, than the median age (25.3 years). The rate of total cartilage thickness change did not differ significantly between the first 2 years and the later 3 years. However, the maximal annualized subregional cartilage loss (OV1) and gain (OV16) were both significantly greater (P < 0.001 and P < 0.05, respectively) during the earlier interval than during the later interval (−115 versus −54 μm OV1 and 116 versus 69 μm OV16).
Conclusion
Cartilage thickening was observed over 5 years following ACL injury, particularly in the medial femorotibial compartment and in younger subjects. Major perturbations in cartilage homeostasis were seen over the first 2 years after ACL rupture, with simultaneous subregional thinning and thickening occurring within the same cartilage plate or compartment.
Summary Objective The Osteoarthritis Initiative (OAI) is aimed at validating (imaging) biomarkers for monitoring progression of knee OA. Here we analyze regional femorotibial (FT) cartilage thickness ...changes over 1 year using 3 Tesla MRI. Specifically, we tested whether changes in central subregions exceed those in the total cartilage plates. Methods The right knees of a subsample of the OAI progression subcohort ( n = 156, age 60.9 ± 9.9 years) were studied. Fifty-four participants had definite radiographic osteoarthritis (OA) (KLG 2 or 3) and a BMI > 30. Mean and minimal cartilage thickness were determined in subregions of the medial/lateral tibia (MT/LT), and of the medial/lateral weight-bearing femoral condyle (cMF/cLF), after paired (baseline, follow up) segmentation of coronal FLASHwe images with blinding to the order of acquisition. Results The central aspect of cMF displayed a 5.8%/2.8% change in mean thickness in the group of 54/156 participants, respectively, with a standardized response mean (SRM) of −0.47/−0.31, whereas cartilage loss in the total cMF was 4.1%/1.9% (SRM −0.49/−0.30). In the central MT, the rate of change was −1.6%/−0.9% and the SRM −0.29/−0.20, whereas for the entire MT the rate was −1.0%/−0.5% and the SRM −0.21/−0.12. Minimal thickness displayed greater rates of change, but lower SRMs than mean thickness. Conclusions This study shows that the rate of cartilage loss is greater in central subregions than in entire FT cartilage plates. The sensitivity to change in central subregions was higher than for the total cartilage plate in the MT and was similar to the total plate in the medial weight-bearing femur.
The effects of exercise on articular hyaline articular cartilage have traditionally been examined in animal models, but until recently little information has been available on human cartilage. ...Magnetic resonance imaging now permits cartilage morphology and composition to be analysed quantitatively in vivo. This review briefly describes the methodological background of quantitative cartilage imaging and summarizes work on short‐term (deformational behaviour) and long‐term (functional adaptation) effects of exercise on human articular cartilage. Current findings suggest that human cartilage deforms very little in vivo during physiological activities and recovers from deformation within 90 min after loading. Whereas cartilage deformation appears to become less with increasing age, sex and physical training status do not seem to affect in vivo deformational behaviour. There is now good evidence that cartilage undergoes some type of atrophy (thinning) under reduced loading conditions, such as with postoperative immobilization and paraplegia. However, increased loading (as encountered by elite athletes) does not appear to be associated with increased average cartilage thickness. Findings in twins, however, suggest a strong genetic contribution to cartilage morphology. Potential reasons for the inability of cartilage to adapt to mechanical stimuli include a lack of evolutionary pressure and a decoupling of mechanical competence and tissue mass.
Summary Objective Increase of subchondral bone area (tAB) in OA has been reported, but it remains unclear if this is specific to OA. We investigated differences in knee tAB after one year in healthy ...subjects and in those with radiographic OA (rOA). Method MR images of 899 right knees from the OA Initiative were acquired at baseline and one year follow-up (year-1). Medial and lateral tibial cartilage (MT and LT) and weight-bearing femoral cartilage (cMF and cLF) were segmented and tAB computed. Subjects were stratified into: healthy controls, pre-rOA (K&L grades 0 and 1, with OA risk factors), established rOA (K&L grades 2–4), and independently with regards to joint space narrowing (without, with medial, lateral and bilateral JSN). Primary analysis tested if tAB was different between baseline and year-1 in rOA. Exploratory analyses investigated whether: (1) tAB changes differed between healthy controls and those with rOA; (2) tAB differences were greater in higher K&L grades; and (3) tAB was different between baseline and year-1 in JSN. Significance was set at P < 0.0125. Results Differences in tAB were found in rOA in MT, cMF and cLF (ranging from +0.2% to +0.4%; P < 0.001), but not in healthy controls or pre-rOA. Rates of change did not differ between groups. Within the JSN groups differences of 0.2–0.4% were found in the femur ( P < 0.05). Conclusion We find that knee tABs differ in rOA between baseline and year-1, but the change was not greater than in healthy knees, and is restricted to the femur in JSN.
Summary Objective Fast low angle shot (FLASH) and double echo steady state (DESS) magnetic resonance imaging (MRI) acquisitions were recently cross-calibrated for quantification of cartilage ...morphology at 3 T. In this pilot study for the osteoarthritis (OA) initiative we compare their test–retest-precision and sensitivity to longitudinal change. Method Nine participants with mild to moderate clinical OA were imaged twice each at baseline, year 1 (Y1) and year 2 (Y2). Coronal 1.5 mm FLASH and sagittal 0.7 mm DESS sequences were acquired; 1.5 mm coronal multiplanar reformats (MPR) were obtained from the DESS. Patellar, femoral and tibial cartilage plates were quantified in a paired fashion, with blinding to time point. Results In the weight-bearing femorotibial joint, average precision errors across plates were 1.8% for FLASH, 2.6% for DESS, and 3.0% for MPR-DESS. Volume loss at Y1 was not significant; at Y2 the average change across the femorotibial cartilage plates was −1.7% for FLASH, −2.8% for DESS, and −0.3% for MPR-DESS. Volume change in the lateral tibia (−5.5%; P < 0.03), and in the medial (−2.9%; P < 0.04) and lateral femorotibial compartments (−3.8%; P < 0.03) were significant for DESS. Conclusions FLASH, DESS and MPR-DESS all displayed adequate test–retest precision. Although the comparison between protocols is limited by the small number of participants and by the relatively small longitudinal change in cartilage morphology in this pilot study, the data suggest that significant change can be detected with MRI in a small sample of OA subjects over 2 years.
Summary Objective To determine whether anatomical thigh muscle cross-sectional areas (MCSAs) and strength differ between osteoarthritis (OA) knees with frequent pain compared with contra-lateral ...knees without pain, and to examine the correlation between MCSAs and strength in painful vs painless knees. Methods Forty-eight subjects (31 women; 17 men; age 45–78 years) were drawn from 4,796 Osteoarthritis Initiative (OAI) participants, in whom both knees displayed the same radiographic stage (KLG2 or 3), one with frequent pain (most days of the month within the past 12 months) and the contra-lateral one without pain. Axial MR images were used to determine MCSAs of extensors, flexors and adductors at 35% femoral length (distal to proximal) and in two adjacent 5 mm images. Maximal isometric extensor and flexor forces were used as provided from the OAI database. Results Painful knees showed 5.2% lower extensor MCSAs ( P = 0.00003; paired t -test), and 7.8% lower maximal extensor muscle forces ( P = 0.003) than contra-lateral painless knees. There were no significant differences in flexor forces, or flexor and adductor MCSAs ( P > 0.39). Correlations between force and MCSAs were similar in painful and painless OA knees (0.44 < r < 0.66). Conclusions Knees with frequent pain demonstrate lower MCSAs and force of the quadriceps (but not of other thigh muscles) compared with contra-lateral knees without knee pain with the same radiographic stage. Frequent pain does not appear to affect the correlations between MCSAs and strength in OA knees. The findings suggest that quadriceps strengthening exercise may be useful in treating symptomatic knee OA.
Summary Objective The Osteoarthritis Initiative (OAI) is targeted at identifying sensitive biomarkers and risk factors of symptomatic knee osteoarthritis (OA) onset and progression. Quantitative ...cartilage imaging in the OAI relies on validated fast low angle shot (FLASH) sequences that suffer from relatively long acquisition times, and on a near-isotropic double echo steady-state (DESS) sequence. We therefore directly compared the sensitivity to cartilage thickness changes and the correlation of these protocols longitudinally. Methods Baseline (BL) and 12 month follow-up data of 80 knees were acquired using 1.5 mm coronal FLASH and 0.7 mm sagittal DESS (sagDESS) sequences. In these and in 1.5 mm coronal multi-planar reconstructions (MPR) of the DESS the medial femorotibial cartilage was segmented with blinding to acquisition order. In the weight-bearing femoral condyle, a 60% (distance between the trochlear notch and the posterior femur) and a 75% region of interest (ROI) were studied. Results The standardized response mean (SRM = mean change/standard deviation of change) in central medial femorotibial (cMFTC) cartilage thickness was −0.34 for coronal FLASH, −0.37 for coronal MPR DESS, −0.36 for sagDESS with the 60% ROI, and −0.38 for the 75% ROI. Using every second 0.7 mm sagittal slice (DESS) yielded similar SRMs in cMFTC for the 60% and 75% ROI from odd (−0.35/−0.36) and even slice numbers (−0.36/−0.39), respectively. BL cartilage thickness displayed high correlations ( r ≥ 0.94) between the three protocols; the correlations of longitudinal changes were ≥0.79 (Pearson) and ≥0.45 (Spearman). Conclusions Cartilage morphometry with FLASH and DESS displays similar longitudinal sensitivity to change. Analysis of every second slice of the 0.7 mm DESS provides adequate sensitivity to change.
Objective:The Osteoarthritis Initiative (OAI) is a multicentre study targeted at identifying biomarkers for evaluating the progression and risk factors of symptomatic knee OA. Here cartilage loss ...using 3 Tesla (3 T) MRI is analysed over 1 year in a subset of the OAI, together with its association with various risk factors.Methods:An age- and gender-stratified subsample of the OAI progression subcohort (79 women and 77 men, mean (SD) age 60.9 (9.9) years, body mass index (BMI) 30.3 (4.7)) with both frequent symptoms and radiographic OA in at least one knee was studied. Coronal FLASHwe (fast low angle shot with water excitation) MRIs of the right knee were acquired at 3 T. Seven readers segmented tibial and femoral cartilages blinded to order of acquisition. Segmentations were quality controlled by one expert.Results:The reduction in mean cartilage thickness (ThC) was greater (p = 0.004) in the medial than in the lateral compartment, greater (p = 0.001) in the medial femur (−1.9%) than in the medial tibia (−0.5%) and greater (p = 0.011) in the lateral tibia (−0.7%) than in the lateral femur (0.1%). Multifactorial analysis of variance did not reveal significant differences in the rate of change in ThC by sex, BMI, symptoms and radiographic knee OA status. Knees with Kellgren–Lawrence grade 2 or 3 and with a BMI >30 tended to display greater changes.Conclusions:In this sample of the OAI progression subcohort, the greatest, but overall very modest, rate of cartilage loss was observed in the weight-bearing medial femoral condyle. Knees with radiographic OA in obese participants showed trends towards higher rates of change than those of other participants, but these trends did not reach statistical significance.
Background: Quantitative magnetic resonance imaging (qMRI) may provide valuable measures of cartilage morphology in osteoarthritis (OA) but has been confined to sequences with relatively long ...acquisition times at 1.5 Tesla (T). Objective: To test the accuracy and precision of knee cartilage qMRI with a fast double echo, steady state (DESS) sequence with water excitation (we) at 3 T. Methods: As a pilot study for the Osteoarthritis Initiative, test-retest MR images were acquired in the knees of 19 participants with no OA to moderate degrees of clinical OA. Two double oblique coronal fast low angle shot (FLASHwe) sequences (1.5 mm slice thickness) were acquired at 3 T, and two sagittal DESSwe sequences (0.7 mm slice thickness). Double oblique coronal multiplanar reformats (MPR) were performed (1.5 mm slice thickness) from the sagittal DESSwe. Knee joint cartilage plates were quantified unpaired in random order with blinding to subject identification. Results: In the femorotibial joint, precision errors (root mean square coefficient of variation in % for unpaired analysis) for cartilage volume and thickness were 3.0–6.4% with coronal FLASHwe, 2.4–6.2% with coronal MPR DESSwe, and 2.3–8.2% with sagittal DESSwe. Correlation coefficients between DESSwe and FLASHwe ranged from r = 0.88 to 1.0. In the femoropatellar joint, precision errors (sagittal DESSwe) were 3.4–8.5%. Conclusions: DESSwe permits accurate and precise analysis of cartilage morphology in the femorotibial joint at 3 T. Further studies are needed to examine the accuracy of DESSwe in the femoropatellar joint and its ability to characterise sensitivity to longitudinal changes in cartilage morphology.
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