Search

Summary Objective 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. Design 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. Results 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, 108]μm). 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, 687]μm). 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, 996]μm) or delayed ACLR (adjusted mean difference: 449 μm [108, 791]μm) than for patients treated with rehabilitation alone. Conclusions 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. Trial registration ISRCTN84752559.

Background: The J-bone graft is presumably representative of iliac crest bone grafts in general and allows anatomic glenoid reconstruction in cases of bone defects due to recurrent traumatic anterior shoulder dislocations. As a side effect, these grafts have been observed to be covered by some soft, cartilage-like tissue when arthroscopy has been indicated after such procedures. Purpose: To evaluate the soft tissue covering of J-bone grafts by use of magnetic resonance imaging (MRI) and histological analysis. Study Design: Case series; Level of evidence, 4. Methods: Patients underwent MRI at 1 year after the J-bone graft procedures. Radiological data were digitally processed and evaluated by segmentation of axial images. Independent from the MRI analysis, 2 biopsy specimens of J-bone grafts were harvested for descriptive histological analysis. Results: Segmentation of the images revealed that all grafts were covered by soft tissue. This layer had an average thickness of 0.87 mm compared with 1.96 mm at the adjacent native glenoid. Of the 2 biopsy specimens, one exhibited evident hyaline-like cartilage and the other presented patches of chondrocytes embedded in a glycosaminoglycan-rich extracellular matrix. Conclusion: J-bone grafts are covered by soft tissue that can differentiate into fibrous and potentially hyaline cartilage. This feature may prove beneficial for delaying the onset of dislocation arthropathy of the shoulder.

Background The goal of this longitudinal study was to investigate the fate of the lateral femoral notch (LFN), which is frequently seen as an impaction fracture of the lateral femoral condyle in patients with anterior cruciate ligament (ACL) tears. Methods Patients who underwent early ACL reconstruction between 2006 and 2010 were reviewed. If post-injury magnetic resonance images showed an LFN greater than 1.5 mm in depth, patients with untreated LFN were followed. Two blinded observers performed quantitative and qualitative imaging analysis. Results Sixteen patients (five women, 11 men) were available for follow-up nine years (six to 10 years) post-injury. The median defect area of the LFN significantly decreased from 2.3 cm2 (range: 0.9–3.8 cm2) to 1.6 cm2 (range: 0.4–3.2 cm2) (P .05). The International Cartilage Repair Society (ICRS) score increased from 1.5 (range: 0–3) post-injury to 2.0 (range: 0–4) at follow-up (P Conclusions The defect area of the LFN decreased overtime, whereas the depth of the impression remained. Focal cartilage lesions were found in all except two patients post-injury and progressed during follow-up. However, patient-reported outcome scores were satisfying.

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 mu m/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 mu m [OV1] and 116 versus 69 mu m [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. (Less)

Quadriceps heads are important in biomechanical stabilization and in the pathogenesis osteoarthritis of the knee. This is the first study to explore the relative distribution of quadriceps head anatomical cross-sectional areas (ACSA) and volumes, and their response to pain and to training intervention.The relative proportions of quadriceps heads were determined in 48 Osteoarthritis Initiative participants with unilateral pain (65% women; age 45-78 years). Quadriceps head volumes were also measured in 35 untrained women (45-55 years) before and after 12-week training intervention. Cross-sectional areas of the vastus medialis (VM), inter-medius (VIM), and lateralis (VL), and of the rectus femoris (RF) were determined from axial T1-weighted MR images.The proportion of the VM on the total quadriceps ACSA increased from proximal to distal. The difference in quadriceps ACSA of painful (vs. pain-free) limbs was -5.4% for the VM (p0.001), -6.8% for the VL (p0.01), -2.8% for the VIM (p=0.06), and +3.4% for the RF (p=0.67) but the VM/VL ratio was not significantly altered. The muscle volume increase during training intervention was +4.2% (p0.05) for VM, +1.3% for VL, +2.0% for VIM (p0.05) and +1.6% for RF.The proportion of quadriceps head relative to total muscle ACSA and volume depends on the anatomical level studied. The results suggest that there may be a differential response of the quadriceps heads to pain-induced atrophy and to training-related hypertrophy. Studies in larger samples are needed to ascertain whether the observed differences in response to pain and training are statistically and clinically significant.

Summary Little is known about changes in human cartilage thickness and subchondral bone plate area (tAB) during growth. The objective of this study was to explore longitudinal change in femorotibial cartilage thickness and tAB in adolescent athletes, and to compare these data with those of mature former athletes. Twenty young (baseline age 16.0 ± 0.6 years) and 20 mature (46.3 ± 4.7 years) volleyball athletes were studied (10 men and 10 women in each group). Magnetic resonance images were acquired at baseline and at year 2-follow-up, and longitudinal changes in cartilage thickness and tAB were determined quantitatively after segmentation. The yearly increase in total femorotibial cartilage thickness was 0.8% (95% confidence interval [CI]: −0.5; 2.1%) in young men and 1.4% (95% CI: 0.7; 2.2%) in young women; the gain in tAB was 0.4% (95% CI: −0.1; 0.8%) and 0.7% (95% CI: 0.2; 1.2%), respectively (no significant difference between sexes). The cartilage thickness increase was greatest in the medial femur, and was not significantly associated with the variability in tAB growth (r = −0.19). Mature athletes showed smaller gains in tAB, and lost >1% of femorotibial cartilage per annum, with the greatest loss observed in the lateral tibia. In conclusion, we find an increase in cartilage thickness (and some in tAB) in young athletes toward the end of adolescence. This increase appeared somewhat greater in women than men, but the differences between both sexes did not reach statistical significance. Mature (former) athletes displayed high rates of (lateral) femorotibial cartilage loss, potentially due to a high prevalence of knee injuries.

ObjectiveTo quantitatively evaluate the position, size, and shape of the menisci in subjects with radiographic knee osteoarthritis (OA) compared to subjects without OA, using magnetic resonance imaging (MRI). MethodsWe studied the right knees of 39 Osteoarthritis Initiative participants (24 women and 15 men with a mean age of 59.6 +/- 8.7 years) with medial compartment radiographic tibiofemoral OA (Kellgren/Lawrence grade of 2 or 3). Subjects were matched individually for age, sex, and height to controls without knee OA and without risk factors for knee OA. The right knees of the controls were used as references. One observer performed manual segmentation of the tibial plateau and the medial and lateral meniscus based on a coronally reconstructed double-echo steady-state sequence with water excitation, focusing on 5 central 3T MRIs. ResultsIn OA knees, there was less meniscal coverage of the medial tibial plateau (435 mm(2) versus 515 mm(2); P = 0.0004), the medial meniscus body showed more extrusion (2.64 mm versus 0.53 mm; P < 0.0001), and the peripheral margin had a more convex shape, i.e., bulged more (mean 0.61 mm versus 0.27 mm; P < 0.0001). The thickness or volume of the medial meniscus body of OA knees did not differ substantially from reference knees. In contrast, in OA knees the lateral meniscus body had a larger volume (mean 266 mm(3) versus 224 mm(3); P = 0.0005) and extruded more (mean 1.16 mm versus -1.01 mm; P < 0.0001), and the external margin bulged more (mean 0.53 mm versus 0.35 mm; P < 0.0001), than in reference knees. ConclusionOur findings indicate altered meniscal position and shape (i.e., more bulging) in both compartments in medial compartment knee OA. These changes may be important features of OA pathogenesis and/or disease consequences. (Less)

Background and Objectives Interscalene brachial plexus blockade is widely used in surgical procedures of the upper limb. Recently, we experienced the complication of a contralateral blockade after ultrasound-guided interscalene block. The clinical appearance was a blockade of both the ipsilateral and the contralateral cervical segments 6 to 8. We hypothesized that epidural spread of local anesthetics could be cause for this phenomenon. Methods We conducted a cadaveric study using ultrasound for needle guidance of interscalene blocks in 5 cadavers by a single investigator using contrast agent. Injections were made either ventral (extrafascial) or dorsal (subfascial) to the prevertebral lamina of the deep cervical fascia. Computed tomography was obtained following each injection with contrast agent immediately after incremental injections of progressively higher volumes. Subsequently, contrast spread to anatomic landmarks was investigated by a radiologist. Results After ultrasound-controlled injection of contrast agent beneath the prevertebral layer of the deep cervical fascia, 4 of the 5 investigated specimens showed contrast enhancement in the epidural space in the consecutive computed tomography scans. After extrafascial injection, none of the investigated specimens showed contrast enhancement in the epidural space. Conclusions Contralateral blockade after ultrasound-guided interscalene injection of local anesthetics is very likely to be the effect of epidural spread. Future in vivo studies are needed to understand the implications of needle location and volume on epidural spread in interscalene blockade.

Summary Objective To compare unbiased estimates of short- vs long-term cartilage loss in osteoarthritic knees. Method 441 knees [216 Kellgren Lawrence (KL) grade 2, 225 KL grade 3] from participants of the Osteoarthritis Initiative were studied over a 4-year period. Femorotibial cartilage thickness was determined using 3 T double echo steady state magnetic resonance imaging, the readers being blinded to time points. Because common measurement time points bias correlations, short-term change (year-1 to year-2: Y1 → Y2) was compared with long-term change (baseline to year-4: BL → Y4), and initial (BL → Y1) with subsequent (Y2 → Y4) observation periods. Results The mean femorotibial cartilage thickness change (standardized response mean) was −1.2%/−0.8% (−0.42/−0.28) over 1 (BL → Y1/Y1 → Y2), −2.1%/−2.5% (−0.56/−0.55) over 2 (BL → Y2/Y2 → Y4), −3.3% (−0.63) over 3 (Y1 → Y4), and −4.5% (−0.78) over 4 years. Spearman correlations were 0.33 for Y1 → Y2 vs BL → Y4, and 0.17 for BL → Y1 vs Y2 → Y4 change. Percent agreement between knees showing progression during Y1 → Y2 vs BL → Y4 was 59%, and 64% for BL → Y1 vs Y2 → Y4. The area under the receiver operating characteristic curve was 0.66 for using Y1 → Y2 to predict BL → Y4, and 0.59 for using BL → Y1 to predict Y2 → Y4 change. Conclusion Weak to moderate correlations and agreement were observed between individual short- vs long-term cartilage loss, and between initial and subsequent observation periods. Hence, longer observation periods are recommended to achieve robust results on cartilage loss in individual knees. At cohort and subcohort level (e.g., KLG3 vs KLG2 knees), the mean cartilage loss increased almost linearly with the length of the observation period and was constant throughout the study.

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 45–78years) 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 12months) 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 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.

Magnetic resonance imaging (MRI) allows one to analyze cartilage physiology in vivo. Cartilage deforms during loading, but little is known about its recovery after deformation. Here we study ‘nocturnal’ changes in knee cartilage thickness and whether postexercise deformation differs between morning and evening. Axial magnetic resonance (MR) images were acquired in the right knees of 17 healthy volunteers (age 23.5 ± 3.0 years) after a normal day, and then after 30 deep knee bends. Coronal images were additionally acquired in 8 of these volunteers after a normal day and then after 2 min of static loading of the leg with 150% body weight. The volunteers then remained unloaded overnight and the same protocol was repeated in the morning. A significant increase (p < 0.01) in cartilage thickness was observed between evening (preexercise) and morning (preexercise): +2.4% in the patella, +8.4% in the medial tibia and +6.2% in the lateral tibia. Deformation in the morning (–6.8/ –4.6/–5.1%) was generally greater than that in the evening (–5.4/–3.2/–3.7%), but this difference did not reach statistical significance. No significant difference in the nocturnal thickness increase (or postexercise deformation) was observed between men and women. We conclude that knee cartilage (thickness) recovers overnight by approximately 2–8%, independent of sex. Given the lack of ‘predeformation’ after nocturnal periods of unloading, morning postexercise deformation of the cartilage may have a greater magnitude than evening postexercise deformation.

To compare several sequence implementations of the 3D FLASH sequence in the context of quantitative cartilage imaging. Test–retest coronal fast low angle shot (FLASH) sequences with water excitation were acquired in knees of 12 healthy participants, using two 1.5 T scanners from the same manufacturer. On one of the scanners, the FLASH was additionally compared with a FLASH VIBE, 75% with 100% slice resolution, a non-selective with a conventional spatial pulse, and “asymmetric echo allowed” with “not allowed”. Implementations of the FLASH showed systematic differences of up to 3.3%, but these were not statistically significant. Precision errors were similar between protocols, but tended to be smallest for the FLASH VIBE with 100% slice resolution (0.6–6.7%). In the medial tibia cartilage volume and thickness differed significantly (P

To explore whether quantitative, three-dimensional measurements of meniscal position and size are associated with knee pain using a within-person, between-knee study design. We studied 53 subjects (19 men, 34 women) from the Osteoarthritis Initiative, with identical radiographic OA grades in both knees, but frequent pain in one and no pain in the other knee. The tibial plateau and menisci were analyzed using coronally reconstructed double echo steady-state sequence with water excitation (DESSwe) MRI. The medial meniscus covered a smaller proportion of the tibial plateau (−5%) and displayed greater extrusion of the body (+15%) in painful than in painless knees (paired t-test; p

Summary Objective The sensitivity to change of quantitative analysis of cartilage in knee osteoarthritis using magnetic resonance imaging (MRI) is compromised by the spatial heterogeneity of cartilage loss. We explore whether extended (medial–lateral) "ordered values" (OVs) are superior to conventional approaches of analyzing subregional cartilage thickness loss and to radiography, in differentiating rates of progression in knees with and without joint space narrowing (JSN). Methods 607 Osteoarthritis Initiative (OAI) participants (308 without and 299 with baseline JSN at baseline) were studied over 12 months. Subregional femorotibial cartilage loss was determined in all knees, and changes in minimum joint space width (mJSW) in a subset of 290 knees. Subregional thickness changes in medial and lateral tibial and femoral cartilages were sorted in ascending order (OV1-16). A Wilcoxon rank-sum test was used to compare rates of change in knees with and without JSN. Results JSN-knees displayed greater cartilage loss than those without JSN, with minimal P -values of 0.008 for femorotibial subregions, 3.3×10 −4 for medial OV1, and 5.4×10 −7 for extended (medial and lateral) OV1. mJSW measurements ( n =290) did not discriminate between longitudinal rates of change in JSN vs no-JSN knees ( P =0.386), whereas medial OV1 ( P =5.1×10 −4 ) and extended OV1 did ( P =2.1×10 −5 ). Conclusion Extended OVs showed higher sensitivity to detecting differences in longitudinal rates of cartilage loss in knees with and without baseline JSN than anatomical (sub)regions and radiography. The OV technique also circumvents challenges of selecting particular regions "a priori" in clinical trials and may thus provide a powerful tool in studying risk factors or treatment efficacy in osteoarthritis.

In vitro effects indicate a putative beneficial effect of Harpagophytum procumbens on cartilage turnover, however, in vivo protective effects on cartilage have yet to be demonstrated. A 7.1T MRI scanner was used to derive measurements of thickness, surface area and volume of the tibial condylar cartilage and to assess their precision (in the case of volume also accuracy) against the volumes of dissected cartilage measured by water displacement. Quantitative measurements were made in 16 rabbits, 6 months after unilateral medial meniscectomy and transection of the anterior cruciate ligament, after which eight of these were given a proprietary extract of Harpagophytum procumbens (HP). A semiquantitative MRI-based grading of the tibial cartilage was also compared with a ‘macroscopic’ grading based on direct visual inspection of dissected joints. The test–retest precision for MRI-based measurement was ≤6.4%. MRI-based measurements correlated well with volumes of surgically resected cartilage (r = 0.97, pair-wise random difference 4.2%). The medial tibial cartilage thickness and volume were about 35% smaller in the operated knees than in the non-operated contralateral knees (p

Summary Objective To compare femorotibial cartilage thickness changes over a 2- vs a 1-year observation period in knees with radiographic knee osteoarthritis (OA). Methods One knee of 346 Osteoarthritis Initiative (OAI) participants was studied at three time points [baseline (BL), year-1 (Y1), year-2 (Y2) follow-up]: 239 using coronal fast low angle shot (FLASH) and 107 using sagittal double echo at steady state (DESS) MR imaging. Changes in cartilage thickness were assessed in femorotibial cartilage plates and subregions, after manual segmentation with blinding to time-point. Results The standardized response mean (SRM) of total joint cartilage thickness over 2 years was modestly higher than over 1 year (FLASH: −0.44 vs −0.32/−0.28 [first/second year]; DESS: −0.42 vs −0.39/−0.18). For the subregion showing the largest change per knee (OV1), the 2-year SRM was similar or lower (FLASH: −1.20 vs −1.22/−1.61; DESS: −1.38 vs −1.64/−1.51) than the 1-year SRM. The changes in total joint cartilage thickness were not significantly different in the first and second year (FLASH: −0.8% vs −0.7%; DESS: −1.3% vs −0.8%) and were negatively correlated. Analysis of smallest detectable changes (SDCs) revealed that only few participants displayed significant progression in both consecutive periods. The location of the subregion contributing to OV1 in each knee was highly inconsistent between the first and second year observation period. Conclusions The SRM of region-based cartilage thickness change in OA is modestly larger following a 2-year vs a 1-year observation period, while it is relatively similar when an OV-approach is chosen. Structural progression displays strong temporal and spatial heterogeneity at an individual knee level that should be considered when planning clinical trials.

The objective of this study was to evaluate the location-specific magnitudes of an exercise intervention on thigh muscle volume and anatomical cross-sectional area, using MRI. Forty one untrained women participated in strength, endurance, or autogenic training for 12 weeks. Axial MR images of the thigh were acquired before and after the intervention, using a T1-weighted turbo-spin-echo sequence (10 mm sections, 0.78 mm in-plane resolution). The extensor, flexor, adductor, and sartorius muscles were segmented between the femoral neck and the rectus femoris tendon. Muscle volumes were determined, and anatomical cross-sectional areas were derived from 3D reconstructions at 10% (proximal-to-distal) intervals. With strength training, the volume of the extensors (+3.1%), flexors (+3.5%), and adductors (+3.9%) increased significantly (P < 0.05) between baseline and follow-up, and with endurance training, the volume of the extensor (+3.7%) and sartorius (+5.1%) increased significantly (P < 0.05). No relevant or statistically significant change was observed with autogenic training. The greatest standardized response means were observed for the anatomical cross-sectional area in the proximal aspect (10-30%) of the thigh and generally exceeded those for muscle volumes. The study shows that MRI can be used to monitor location-specific effects of exercise intervention on muscle cross-sectional areas, with the proximal aspect of the thigh muscles being most responsive.

SummaryObjectiveTo assess the presence, location, type and size of denuded areas of subchondral bone (dAB) in the femorotibial joint, measured quantitatively with 3T MRI, in a large subset of OAI participants.MethodsOne knee of 633 subjects (250 men, 383 women, aged 61.7±9.6y) were studied, spanning all radiographic osteoarthritis (OA) stages. dABs were determined quantitatively using segmentations of coronal FLASHwe images, representing areas where the subchondral bone was not covered by cartilage. Post hoc visual examination of segmented images determined whether dABs represented full thickness cartilage loss or internal osteophyte.Results7% Of the knees were Kellgren & Lawrence (KL) grade 0, 6% grade 1, 41% grade 2, 41% grade 3, and 5% grade 4. 39% Of the participants (48% of the men and 33% of the women) displayed dABs; 61% of the dABs represented internal osteophytes. 1/47 Participants with KL grade 0 displayed ‘any’ dAB whereas 29/32 of the KL grade 4 knees were affected. Even as early as KL grade 1, 29% of the participants showed dABs. There were significant relationships of dAB with increasing KL grades (P

Summary Objective To explore whether longitudinal change in cartilage thickness in femorotibial subregions of knees with radiographic osteoarthritis (ROA) differs from that in healthy knees. Methods 3T coronal magnetic resonance (MR) images were acquired in 152 women at seven clinical centers at baseline (BL) and 24 months. Knees from 75 women with signs of ROA in either anterior–posterior or Lyon schuss radiographs were compared with those from 77 asymptomatic healthy controls without ROA to identify knees showing greater change in cartilage thickness than expected based on observations in healthy knees. The femorotibial cartilage thickness was determined in BL and follow-up MR images across five tibial and three femoral subregions in the medial/lateral compartment, respectively. Results A substantial portion of knees with ROA were classified as having longitudinal cartilage thinning (28%) or thickening (20%) in at least one medial femorotibial subregion based on comparisons to longitudinal changes observed in healthy knees; only 5% showed both subregional thinning and thickening across (different) medial subregions at the same time. Whereas the estimated proportion of Kellgren Lawrence grade (KLG) 3 knees ( n =28) with significant medial cartilage thinning (46%) was substantially greater than that with cartilage thickening (18%), the estimated percentages of KLG2 knees ( n =30) with significant medial thinning (20%) and thickening (23%) were similar. Conclusion This exploratory study indicates that OA may not be a one-way-road of cartilage loss. Subregional analysis suggests that, compared with healthy knees, cartilage changes in ROA may occur in both directions. Medial femorotibial cartilage thickening was observed as frequently as cartilage thinning in KLG2 knees.

Objective To determine by magnetic resonance imaging (MRI), whether knees with advanced radiographic disease (medial joint space narrowing [mJSN]) encounter greater longitudinal cartilage loss than contralateral knees with earlier disease (no or less mJSN). Methods Participants were selected from 2,678 cases in the Osteoarthritis Initiative, based on exhibition of bilateral pain, body mass index >25 (kg/m2), mJSN in 1 knee, no or less mJSN in the contralateral knee, and no lateral JSN in both knees. Eighty participants (mean ± SD age 60.6 ± 9.1 years) fulfilled these criteria. Medial tibial and femoral cartilage morphology was analyzed from the baseline and the 1-year followup MRI (sagittal double echo at steady state by 3.0T) of both knees by experienced readers blinded to the time point and mJSN status. Results Knees with more radiographic mJSN displayed greater medial cartilage loss (−80 μm) assessed by MRI than contralateral knees with less mJSN (−57 μm). The difference reached statistical significance in participants with an mJSN grade of 2 or 3 (P = 0.005–0.08), but not in participants with an mJSN grade of 1 (P = 0.28–0.98). In knees with more mJSN, cartilage loss increased with higher grades of mJSN (P = 0.003 in the medial femur). Knees with an mJSN grade of 2 or 3 displayed greater cartilage loss in the weight-bearing medial femur than in the posterior femur or in the medial tibia (P = 0.048). Conclusion Knees with advanced mJSN displayed greater cartilage loss than contralateral knees with less mJSN. These data suggest that radiography can be used to stratify fast structural progressors, and that MRI cartilage thickness loss is more pronounced at advanced radiographic disease stage.

Summary Objective To identify subregional differences in femorotibial cartilage morphology between healthy controls and women with different grades of radiographic knee osteoarthritis (OA). Design 158 women aged ≥40 years were studied. Weight-bearing extended anterior-posterior (AP) and Lyon schuss radiographs were obtained and the Kellgren Lawrence grade (KLG) determined. 97 women had a body mass index (BMI)≤28, no symptoms, and were AP KLG0. 61 women had a BMI≥30, symptoms in the target knee, and mild (KLG2=31) to moderate (KLG3=30) medial femorotibial radiographic OA in the AP views. Coronal spoiled gradient echo water excitation sequences were acquired at 3.0 Tesla. Total plate and regional measures of cartilage morphology of the weight-bearing femorotibial joint were quantified. Results KLG2 participants displayed, on average, thicker cartilage than healthy controls in the medial femorotibial compartment (particularly anterior subregion of the medial tibia (MT) and peripheral [external, internal] subregions of the medial femur), and in the lateral femur. KLG3 participants displayed significantly thinner cartilage than KLG0 participants in the medial weight-bearing femur (central subregion), in the external subregion of the MT, and in the internal subregion of the lateral tibia. These differences were generally unaffected when possible effects of demographic covariates were considered. Conclusions The results indicate that in femorotibial OA regional cartilage thickening and thinning may occur, dependent on the (radiographic) disease status of the joint. These changes appear to display a heterogeneous spatial pattern, where certain subregions are more strongly affected than others.

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.

Objectives:To examine whether the quantity of cartilage or semiquantitative scores actually differ in knees with mild radiographic osteoarthritis compared with knees without osteoarthritis.Methods:Framingham Osteoarthritis Study participants had knee tibiofemoral magnetic resonance imaging-based measurements of cartilage. Using three-dimensional FLASH-water excitation sequences, cartilage volume, thickness and subregional cartilage thickness were measured and cartilage scored semiquantitatively (using the whole-organ magnetic resonance imaging score; WORMS). Using weight-bearing radiographs, mild osteoarthritis was defined as Kellgren/Lawrence (K/L) grade 2 and non-osteoarthritis as K/L grade 0. Differences between osteoarthritis and non-osteoarthritis knees in median cartilage measurements were tested using the Wilcoxon rank sum test.Results:Among 948 participants (one knee each), neither cartilage volume nor regional thickness were different in mild versus non-osteoarthritis knees. In mild osteoarthritis, cartilage erosions in focal areas were missed when cartilage was quantified over large regions such as the medial tibia. For some but not all subregions of cartilage, especially among men, cartilage thickness was lower (pConclusions:In mild osteoarthritis, the focal loss of cartilage is missed by quantitative measures of cartilage volume or thickness over broad areas. Regional cartilage volume and thickness (eg, medial tibia) are not different in mild osteoarthritis versus non-osteoarthritis. Subregional thickness may be decreased in mild osteoarthritis. Semiquantitative scoring that assesses focal cartilage damage differentiates mild osteoarthritis from non-osteoarthritis.

Malalignment is known to affect the medial-to-lateral load distribution in the tibiofemoral joint. In this longitudinal study, we test the hypothesis that subchondral bone surface areas functionally adapt to the load distribution in malaligned knees. Alignment (hip–knee–ankle angle) was measured from full limb films in 174 participants with knee osteoarthritis. Coronal magnetic resonance images were acquired at baseline and 26.6 ± 5.4 months later. The subchondral bone surface area of the weight-bearing tibiofemoral cartilages was segmented, with readers blinded to the order of acquisition. The size of the subchondral bone surface areas was computed after triangulation by proprietary software. The hip–knee–ankle angle showed a significant correlation with the tibial (r2 = 0.25, P < 0.0001) and femoral (r2 = 0.07, P < 0.001) ratio of medial-to-lateral subchondral bone surface area. In the tibia, the ratio was significantly different between varus (1.28:1), neutral (1.18:1), and valgus (1.13:1) knees (analysis of variance [ANOVA]; P < 0.00001). Similar observations were made in the weight-bearing femur (0.94:1 in neutral, 0.97.1 in varus, 0.91:1 in valgus knees; ANOVA P = 0.018). The annualized longitudinal increase in subchondral bone surface area was significant (P < 0.05) in the medial tibia (+0.13%), medial femur (+0.26%), and lateral tibia (+0.19%). In the medial femur, the change between baseline and follow-up was significantly different (ANOVA; P = 0.020) between neutral, varus, and valgus knees, with the increase in surface area being significantly greater (P = 0.019) in varus than in neutral knees. Tibiofemoral subchondral bone surface areas are shown to be functionally adapted to the medial-to-lateral load distribution. The longitudinal findings indicate that this adaptational process may continue to take place at advanced age.

Objective. Malalignment is known to alter medial-to-lateral femorotibial load distribution and to affect osteoarthritis (OA) progression in the mechanically stressed compartment. We investigated the pattern of cartilage loss in neutral, varus, and valgus knees. Methods. Alignment was measured from full-limb radiographs in 174 participants with symptomatic knee OA. Coronal magnetic resonance images were acquired at baseline and a mean SD of 26.6 5.4 months later. The weight-bearing femorotibial cartilages were segmented from paired images. Cartilage volume, surface area, and thickness were determined in total cartilage plates and defined subregions using proprietary software. Results. The medial-to-lateral ratio of femorotibial cartilage loss was 1.4:1 in neutral knees (n 74), 3.7:1 in varus knees (n 57), and 1:6.0 in valgus knees (n 43). The relative contribution of cartilage thickness change tended to be greater in knees with mild cartilage loss, whereas the increase of denuded area was greater in knees with accelerated cartilage loss. In both varus and neutral knees, the greatest changes were observed in the same subregions of the medial femorotibial compartment (central and external medial tibia, and central medial femur). In valgus and neutral knees, the subregions with the greatest changes in the lateral femorotibial compartment were also similar (internal and central lateral tibia, external lateral femur). Conclusion. The medial-to-lateral rate of femorotibial cartilage loss strongly depended on alignment. Subregions of greater-than-average cartilage loss within the stressed compartment were, however, similar in neutral, varus, and valgus knees. This indicates that the medial-to-lateral loading pattern is different, but that the (sub)regional loading pattern may not differ substantially between neutral and malaligned knees.

Bone mass predicts a high proportion of variability in bone failure strength but is known to overlap among subjects with and without fractures. Here, we tested the hypothesis that trabecular bone microstructure, determined with micro-computed tomography (microCT), can improve the prediction of experimental failure loads in the distal forearm compared with bone mass alone. The right forearm and left distal radius of 130 human specimens were examined. Bone mineral density (BMD) was measured with peripheral dual energy X-ray absorptiometry (DXA). The specimens were mechanically tested to failure in a fall configuration, with the hand, elbow, ligaments, and tendons intact. Cylindrical bone samples from the metaphysis of the contralateral distal radius were obtained adjacent to the subchondral bone plate and scanned with microCT. When analyzing the total sample, BMD of the distal radius displayed a correlation of r = 0.82 with mechanical failure loads. After excluding 21 specimens with no obvious radiological sign of fracture after the test, the correlation increased to r = 0.85. When only including 79 specimens with loco typico fractures, the correlation was r = 0.82. The microstructural parameters showed correlation coefficients with the failure loads ofor =0.55 and did not add significant information to DXA in predicting failure loads in multiple regression models. These findings suggest that, under experimental conditions of mechanically testing entire bones, measurement of bone microstructure does not improve the prediction of distal radius bone strength. Determination of bone microstructure may thus be less promising in improving the prediction of fractures than commonly assumed.

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.

Objective Progressive knee osteoarthritis (OA) is believed to result from local factors acting in a systemic environment. Previous studies have not examined these factors concomitantly or compared quantitative and qualitative cartilage loss outcomes. The aim of this study was to test whether meniscal damage, meniscal extrusion, malalignment, and laxity each predicted tibiofemoral cartilage loss after controlling for the other factors. Methods Laxity and alignment were measured at baseline in individuals with knee OA. Magnetic resonance imaging included spin-echo coronal and sagittal imaging for meniscal scoring and axial and coronal spoiled gradient echo sequences with water excitation for cartilage quantification. Tibial and weight-bearing femoral condylar subchondral bone area and cartilage surface were segmented. Cartilage volume, denuded bone area, and cartilage thickness were quantified in each plate, with progression defined as cartilage loss >2 times the coefficient of variation for each plate. Qualitative outcome was assessed as worsening of the cartilage score. Logistic regression analysis with generalized estimating equations yielded odds ratios for each factor, adjusting for age, sex, body mass index, and the other factors. Results We studied 251 knees in 153 persons. After full adjustment, medial meniscal damage predicted medial tibial cartilage volume loss and tibial and femoral denuded bone increase, while varus malalignment predicted medial tibial cartilage volume and thickness loss and tibial and femoral denuded bone increase. Lateral meniscal damage predicted every lateral outcome. Laxity and meniscal extrusion had inconsistent effects. After full adjustment, no factor except medial laxity predicted qualitative outcome. Conclusion Using quantitative cartilage loss assessment, local factors that independently predicted tibial and femoral loss included medial meniscal damage and varus malalignment (medially) and lateral meniscal damage (laterally). A measurement of quantitative outcome was more sensitive at revealing these relationships than a qualitative approach.

SummaryObjectiveFast 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 3T. In this pilot study for the osteoarthritis (OA) initiative we compare their test–retest-precision and sensitivity to longitudinal change.MethodNine participants with mild to moderate clinical OA were imaged twice each at baseline, year 1 (Y1) and year 2 (Y2). Coronal 1.5mm FLASH and sagittal 0.7mm DESS sequences were acquired; 1.5mm 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.ResultsIn 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

MRI-based cartilage morphometry was previously validated in the absence of gadopentate dimeglumine (Gd-DTPA). However, Gd-DTPA is required for compositional (proteoglycan) imaging using delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). Therefore, the effect of Gd-DTPA on cartilage morphometry was studied. A total of 165 female participants (67 with and 98 without osteoarthritis [OA]) were imaged at 3.0 Tesla before and 2 hr after intravenous Gd-DTPA injection. Flip angles in post-Gd-DTPA scans varied between 12° and 35°. Cartilage volume and thickness of post- vs. pre-Gd-DTPA scans showed intraclass correlation coefficients (ICCs) of 0.85 ≥ r ≥ 0.95, mean differences between –2.1% and +1.1%, and standard deviations (SDs) of differences between 4.7% and 9.2%. Mixed-effect models found no consistent impact of flip angle and OA status on post- vs. pre-Gd-DTPA differences. Accurate morphological measurements of cartilage can be obtained after Gd-DTPA injection, allowing compositional and morphological imaging to be combined into one session. Magn Reson Med 58:402–406, 2007. © 2007 Wiley-Liss, Inc.

Background The goal of this present study was to precisely determine the dimension and location of the impaction fracture on the lateral femoral condyle in patients with an ACL rupture. Methods All patients with post-injury bi-plane radiographs and MRI images after sustaining a tear to the anterior cruciate ligament were included. Lateral radiographs of the affected knee were inspected for a lateral femoral notch sign. MRIs of patients with a lateral condylopatellar sulcus ≥1.5 mm were used to segment and measure the lateral condylopatellar sulcus. The MRI examination was interpreted by an expert in musculoskeletal radiology. The study was approved by the ethics committee of the state of Salzburg. Results A “lateral femoral notch sign”was seen in 50 patients. The average total surface area of the lateral femoral condyle was 3271.7 mm2 (SD 739.5 mm2). The defect had a mean surface area of 266.1 mm2 (SD 125.5 mm2), a mean volume of 456.5 mm3 (SD 278.5 mm3), a mean depth of 3.0 mm (SD 0.8 mm). On average 169 mm2 (SD 99.6 mm2) of the surface of the condyle were affected by the impaction fracture which corresponds to 5.2 % (SD 2.8 %) of the surface of the lateral femoral condyle. In 51 % the impaction fracture was located in the central-external area of the femoral condyle. Conclusions In cases of a clinically suspected ACL rupture lateral radiographs of the knee should be checked for a lateral femoral notch sign further MRI for confirmation should be performed. Knowing of the precise defect on the lateral femoral condyle is an additionally valuable information, as concomitant injuries to a rupture of the anterior cruciate ligament increase the risk for early-onset osteoarthritis in the future.

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).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 (KL grades 0 and 1, with OA risk factors), established rOA (KL 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 KL grades; and (3) tAB was different between baseline and year-1 in JSN. Significance was set at P 0.0125.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).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.

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.

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.

High-resolution magnetic resonance imaging (hrMRI) has recently made it possible to evaluate trabecular bone structure in vivo. Despite obvious gender differences in fracture incidence at the distal radius, little is known about gender differences in trabecular bone microarchitecture and its relationship to the structural strength of the forearm. The aim of this study was to determine trabecular bone structure in the distal radius of elderly women and men and its correlation with failure loads of the distal radius as determined in a fall configuration. Specifically, we tested the hypotheses that structural indices differ between women and men and that they offer information that is independent from BMD for predicting structural strength. Intact right arms were obtained from 73 formalin-fixed cadavers (age 80±11 years, 43 women, 30 men). Trabecular structural indices (apparent bone volume fraction [app. BV/TV], trabecular number [app. Tb.N], trabecular separation [app. Tb.Sp], trabecular thickness [app. Tb.Th] and fractal dimension [Frac.Dim]) were assessed in the distal metaphysis, using hrMRI with 156 µm in-plane resolution and proprietary digital image analysis, while BMD was measured with dual X-ray absorptiometry (DXA). Women displayed significantly lower BMD (−29.8%, p

Background: Knowledge of the deformational behaviour of articular cartilage in vivo is required to understand the pathogenesis of osteoarthritis and the mechanical target environment of prospective cartilage transplant recipients. Objectives: To study the in vivo deformational behaviour of patellar and femorotibial cartilage for different types of physiological activities; and to test the hypothesis that in vivo deformation of cartilage is modified by intense physical exercise. Methods: Magnetic resonance imaging and 3D digital image analysis were used to determine cartilage volume before and after physical activity in the patella of 12 volunteers (knee bends, squatting, normal gait, running, cycling). Deformation of femorotibial cartilage was investigated in 10 subjects (knee bends, static compression, high impact loading). Patellar cartilage deformation after knee bends was compared in seven professional weight lifters, seven sprinters, and 14 untrained volunteers. Results: Patellar cartilage deformation was –5.9% after knee bends, –4.7% after squatting, –2.8% after normal walking, –5.0% after running, and –4.5% after cycling. The pattern of patellar cartilage deformation corresponded to the range of motion involved in the particular activity. Tibial cartilage deformation was greatest under high impact loading (–7%), but small for other activities. No significant difference was found between athletes and non-athletic controls. Conclusions: Patellar cartilage deformation shows a "dose dependent" response, where more intense loading leads to greater deformation. Relatively little deformation was observed in the femorotibial joint, except during high impact activities. The findings provide no evidence that adult human cartilage properties are amendable to training effects in vivo.

Objective. Quantitative magnetic resonance imaging (MRI) of articular cartilage represents a powerful tool in osteoarthritis (OA) research, but has so far been confined to a field strength of 1.5T. The aim of this study was to evaluate the precision of quantitative MRI assessments of human cartilage morphology at 3.0T and to correlate the measurements at 3.0T with validated measurements at 1.5T. Methods. MR images of the knee of 15 participants with OA and 15 healthy control subjects were acquired using Siemens 1.5T and 3.0T scanners. Double oblique coronal scans were obtained at 1.5T with a 1.5-mm partition thickness, at 3.0T with a 1.5-mm partition thickness, and at 3.0T with a 1.0-mm partition thickness. Cartilage volume, thickness, and surface area of the femorotibial cartilage plates were quantified using proprietary software. Results. For 1.5-mm partition thickness at 1.5T, the precision error was 3.0% and 2.6% for cartilage volume and cartilage thickness, respectively. The error was smaller for a 1.5-mm partition thickness at 3.0T (2.6% and 2.5%) and still smaller for a 1.0-mm partition thickness at 3.0T (2.1% and 2.0%). Correlation coefficients between values obtained at 3.0T and 1.5T were high (r > 0.96), with no significant deviation between the two field strengths. Conclusion. Quantitative MRI measurement of cartilage morphology at 3.0T (partition thickness 1 mm) was found to be accurate and tended to be more reproducible than at 1.5T (partition thickness 1.5 mm). Imaging at 3.0T may therefore provide superior ability to detect changes in cartilage status over time and to determine responses to treatment with structuremodifying drugs.

We explore the relationship of region-specific densitometric and geometry-based (cortical) parameters at the distal radial metaphysis with gender, age, and osteoporotic status, using multislice computed tomography (CT). We specifically test the hypothesis that these parameters can improve the prediction of mechanical strength of the distal radius vs bone mass (bone mineral content [BMC]). The BMC was determined in 56 forearm specimens with peripheral dual-energy X-ray absorptiometry (DXA). Trabecular and cortical density and geometric properties of the metaphyseal cortex were determined using multislice CT and proprietary image analysis software. Specimens were tested to failure in a fall simulation, maintaining the integrity of the elbow joint and hand. Women displayed significantly lower failure strength (–34%), BMC (–35%), trabecular density (–26%), and cortical area (–12%) than men. The reduction of trabecular density with age and osteoporotic status was stronger than that of cortical density or thickness. DXA explained approx 50% ( r 2 ) of the variability in bone failure loads. This proportion was slightly increased (55%) when adding geometry-based parameters. The study suggests that high-resolution tomographic measurements with current clinical imaging methodology can marginally improve the prediction of mechanical failure strength. Further efforts are required to improve spatial resolution for determining metaphyseal cortical properties clinically.

The diagnosis of osteoporosis is generally based on the assessment of bone mineral content with dual X-ray absorptiometry (DXA) but does not account for the spatial distribution and inherent material properties of the tissue. Peripheral quantitative computed tomography (pQCT) permits one to measure the compartment-specific density and geometry-based parameters of cortical bone. Quantitative ultrasound (QUS) parameters are associated with material properties of cortical bone. The purpose of this study was to test the hypothesis that pQCT and cortical QUS provide additional information to DXA in predicting structural strength of the distal radius. The intact right arm and the isolated left radius were harvested from 70 formalin-fixed cadavers (age 79+/-11 years). The bone mineral content (BMC) was assessed with DXA at the radial metaphysis and shaft. pQCT was also used at the metaphysis and the shaft, while QUS was employed only at the shaft. The failure loads of the radius were assessed by use of a 3-point bending test (isolated radius) and a complex fall simulation (intact arm). The BMC (DXA) displayed a correlation of r=0.96 with the failure moments in 3-point bending ( P

Objective T scores (an indicator of the difference between patients and young healthy subjects) and Z scores (an indicator of the difference between patients and age-matched healthy subjects) are used in the diagnosis of osteoporosis and form the current basis for the definition of osteoporosis by the World Health Organization. We tested the feasibility of using T and Z scores derived from quantitative cartilage imaging with magnetic resonance imaging (MRI) for the diagnosis of osteoarthritis (OA). Methods High-resolution MR images of tibial cartilage were acquired from 126 young healthy adults (ages 20–35 years), 24 age-matched elderly healthy adults (ages 50–75 years), 7 OA patients prior to tibial osteotomy, and 7 OA patients prior to knee arthroplasty. Cartilage volume, thickness, surface area, and original joint surface area (before onset of disease) were determined in the medial and lateral tibia. Results The cartilage volume of the medial tibia of osteotomy patients with varus malalignment displayed moderate T scores (−1.0), and more negative T scores (−3.8) were observed in knee arthroplasty patients with varus malalignment. Normalization of the cartilage volume to the original joint surface area substantially enhanced the scores in patients undergoing osteotomy (−2.3) and in patients undergoing knee arthroplasty (−5.5), and this was superior to the normalization ratios of cartilage volume to body height and cartilage volume to body weight, in terms of distinguishing the loss of articular cartilage. Conclusion Quantitative analysis of OA by MRI is feasible using T and Z scores. However, cartilage volume should be normalized to the individual joint surface area in order to maximize the discriminatory power of this technique for the diagnosis of OA.

We tested the hypothesis that muscle cross-sectional areas (MCSAs) are more highly (and independently) correlated with cartilage morphology than are body height and weight, and that the physiological reduction of cartilage thickness with aging is associated with a proportional, age-dependent decrease in MCSAs. In 59 asymptomatic individuals (23–75 years old), morphological parameters of the knee cartilages (volume, thickness, and bone–cartilage interface area), and MCSAs were determined from magnetic resonance imaging (MRI) data. Multiple regression models were used to calculate which proportion of the variability of the normal cartilage morphology can be predicted based on independent variables. MCSAs and body height and weight showed correlation coefficients of +0.66, +0.60, and +0.25, respectively, with knee-joint cartilage volume. The correlation coefficients with cartilage thickness were +0.44, +0.35, and +0.24, respectively. Age accounted for a significant (P < 0.01) reduction in cartilage thickness, but there was no proportional change of MCSAs. Approximately 76% of the variability of the knee cartilage volume could be predicted from independent variables in a multiple regression model with MCSAs contributing significant, independent information. In conclusion, we find that MCSAs are more highly correlated with cartilage morphology than are body height and weight. The significant decrease in cartilage volume and thickness with age is not associated with a proportional decrease in MCSAs. Anat Rec Part A 270A:175–184, 2003. © 2003 Wiley-Liss, Inc.

Objective Alterations of cartilage morphology and mechanical properties occur in osteoarthritis, but it is unclear whether similar changes also take place physiologically during aging, in the absence of disease. In this in vivo study, we tested the hypothesis that thinning of knee joint cartilage occurs with aging and that elderly subjects display a different amount of cartilage deformation than do young subjects. Methods We evaluated 30 asymptomatic subjects ages 50–78 years. Morphologic parameters for the knee cartilage (mean and maximum thickness, surface area) were computed from magnetic resonance imaging data. Results were compared with those in 95 young asymptomatic subjects ages 20–30 years. Deformation of the patellar cartilage was determined after the subjects performed 30 knee bends. Results There was a significant reduction of patellar cartilage thickness in elderly women (−12%; P < 0.05), but not in elderly men (−6%). Femoral cartilage was significantly thinner in both sexes (−21% in women, −13% in men; P < 0.01), whereas tibial cartilage thickness displayed only nonsignificant trends (−10% in women, −7% in men). Patellar cartilage deformation was −2.6% in elderly women and −2.2% in elderly men. These values were significantly lower (P < 0.05) than those in young subjects. Conclusion We confirmed the hypothesis that knee cartilage becomes thinner during aging, in the absence of cartilage disease, but that the amount of reduction differs between sexes and between compartments of the knee joint. We show that under in vivo loading conditions, elderly subjects display a lower level of cartilage deformation than do healthy young subjects.

SummaryObjectiveCartilage spin–spin magnetic resonance imaging (MRI) relaxation time (T2) represents a promising imaging biomarker of “early” osteoarthritis (OA) known to be associated with cartilage composition (collagen integrity, orientation, and hydration). However, no longitudinal imaging studies have been conducted to examine cartilage maturation in healthy subjects thus far. Therefore, we explore T2 change in the deep and superficial cartilage layers at the end of adolescence.MethodsTwenty adolescent and 20 mature volleyball athletes were studied (each 10 men and 10 women). Multi-echo spin-echo (MESE) images were acquired at baseline and 2-year follow-up. After segmentation, cartilage T2 was calculated in the deep and superficial cartilage layers of the medial tibial (MT) and the central, weight-bearing part of the medial femoral condyle (cMF), using five echoes (TE 19.4–58.2 ms).Results16 adolescent (6 men, 10 women, baseline age 15.8 ± 0.5 years) and 17 mature (nine men, eight women, age 46.5 ± 5.2 years) athletes had complete baseline and follow-up images of sufficient quality to compute T2. In adolescents, a longitudinal decrease in T2 was observed in the deep layers of MT (−2.0 ms; 95% confidence interval (CI): [−3.4, −0.6] ms; P

OBJECTIVE: Knee osteoarthritis commonly requires joint replacement, substantially reduces quality of life and increases healthcare utilisation and costs. This study aimed to identify whether quantitative measures of articular cartilage structure predict knee replacement, and to establish their utility as outcomes in clinical trials of disease-modifying therapy. METHODS: A nested case-control study was performed in Osteoarthritis Initiative participants, a multicentre observational cohort of 4796 participants with or at risk of knee osteoarthritis. 127 knees were replaced between baseline and 4 years follow-up, and one control knee per case matched for baseline radiographic disease stage (Kellgren-Lawrence grade; KLG), gender and age. Quantitative cartilage measures were obtained from 3 T magnetic resonance images at the exam before knee replacement, and longitudinal change during the previous 12 months when available (n=110). RESULTS: Cartilage thickness loss in the central and total medial femorotibial compartment (primary and secondary predictor variables) was significantly greater in case than control knees (AUC=0.59/0.58). Differences in cartilage loss were greater at earlier than later radiographic disease stages (p

Purpose: Patellofemoral joint (PFJ) osteoarthritis (OA) is a prevalent disease affecting young and elderly individuals and is recognized as a potent source of knee symptoms. Using quantitative MR image analysis it was reported that the femoral trochlea undergoes cartilage thinning within the first two years after an ACL tear and that such thinning wasmore frequent in older individuals. It is however unknown whether these changes continue (and if yes, at which magnitude) over longer follow-up periods. Thus, the purpose of the present work was to study the rate of change in cartilage thickness in the PFJ during the period of 2-5years after ACL tear and to explore differences related to age, gender and BMI. Methods: 121 young active adults (32 women, 26.0 4.9 years) with an acute ACL tear were included in a randomized control trial (the KANON-trial). The study compared rehabilitation plus early ACL reconstruction (n1⁄462), with rehabilitation plus the option of having delayed ACL reconstruction if needed (n1⁄459). Mean cartilage thickness was assessed by manual segmentation in the patella and femoral trochlea with blinding to time points and treatment groups. Crude and adjusted (age, sex & BMI) statistical testing was performed to explore the magnitude of cartilage loss between baseline (BL, within 4 weeks from ACL tear)-2years and 2-5years in the patella and the femoral trochlea. Results: 107 of 121 participants had a complete set of MR images at BL, 2 and 5 year follow up. Mean change of cartilage thickness in patella and trochlea was -8.9mm/[-26.4, 8.5] and -44.9mm/[-67.0, -22.8] (mean/[95% CI]) over the first 2 years after ACL tear and -3.8mm/[-22.1, 14.6] and -1.0mm/[-15.6, 13.5] over the period between 2-5 years, respectively. Older patients (above median age, 25.63years) lost significantly more cartilage thickness than younger individuals (below median age) in both the patella (p1⁄40.022) and in the trochlea (p1⁄40.009) over the first 2 years. Similar differences were seen in the patella (p1⁄40.004), but not in the trochlea (p1⁄40.17), between 2-5years (Table 1). Compared to individuals with a lower BMI (belowmedian, 23.66kg/m), individuals with a higher BMI (above median) had a significant decrease in cartilage thickness of the trochlea over the first 2 years (p1⁄40.045) but not between 2-5years. No corresponding differences related to BMI or gender were observed in the patella (Table 1). In a multi-variate model including age, BMI and gender, older age at ACL tear significantly increased the odds of losing cartilage thickness in the femoral trochlea (OR 1.06, 95% CI 1.01, 1.10) over the first 2 years after tear and in the patella (OR 1.04, 1.00, 1.08) in the period 2-5 years. Conclusions: These results show that cartilage loss in the femoral trochlea may be an early and temporary event occurring over the first 2 years after ACL tear. In contrast to that, cartilage loss in the patellar cartilage seems to occur later than 2 years after the ACL tear. Older age seems to be a risk factor for these changes. Our results indicate that different mechanisms may drive loss of cartilage in the femoropatellar joint after ACL tear.

To quantitatively evaluate the position, size, and shape of the menisci in subjects with radiographic knee osteoarthritis (OA) compared to subjects without OA, using magnetic resonance imaging (MRI).We studied the right knees of 39 Osteoarthritis Initiative participants (24 women and 15 men with a mean age of 59.6 ± 8.7 years) with medial compartment radiographic tibiofemoral OA (Kellgren/Lawrence grade of 2 or 3). Subjects were matched individually for age, sex, and height to controls without knee OA and without risk factors for knee OA. The right knees of the controls were used as references. One observer performed manual segmentation of the tibial plateau and the medial and lateral meniscus based on a coronally reconstructed double-echo steady-state sequence with water excitation, focusing on 5 central 3T MRIs.In OA knees, there was less meniscal coverage of the medial tibial plateau (435 mm(2) versus 515 mm(2) ; P = 0.0004), the medial meniscus body showed more extrusion (2.64 mm versus 0.53 mm; P0.0001), and the peripheral margin had a more convex shape, i.e., bulged more (mean 0.61 mm versus 0.27 mm; P0.0001). The thickness or volume of the medial meniscus body of OA knees did not differ substantially from reference knees. In contrast, in OA knees the lateral meniscus body had a larger volume (mean 266 mm(3) versus 224 mm(3) ; P = 0.0005) and extruded more (mean 1.16 mm versus -1.01 mm; P0.0001), and the external margin bulged more (mean 0.53 mm versus 0.35 mm; P0.0001), than in reference knees.Our findings indicate altered meniscal position and shape (i.e., more bulging) in both compartments in medial compartment knee OA. These changes may be important features of OA pathogenesis and/or disease consequences.

s / Osteoarthritis and Cartilage 20 (2012) S10–S53 S13 Conclusions: These results show that the shape of the hip as quantified by an SSM is able to predict the risk of THR, whereas variation in shape can not predict the development of clinical OA. The latter might be a result of the poor reliability of the ACR criteria. We observed that 87% of the individuals who had clinical OA at baseline, did not have clinical OA anymore after 5 years. In conclusion, minor shape variations at baseline have a good predictive value for the development of end-stage OA and may be used as a biomarker to predict the future risk for THR. 8 ASSESSMENT OF PERFUSION IN OSTEOARTHRITIS INDUCED BONE MARROW LESIONS USING DYNAMIC CONTRAST ENHANCED MAGNETIC RESONANCE IMAGING J.P. Dyke , D. Wheaton , L. Ling , C. Talmo , W.F. Harvey , D.J. Hunter . Weill Cornell Med. Coll., New York, NY, USA; New England Baptist Hosp., Boston, MA, USA; Royal North Shore Hosp. and Northern Clinical Sch., Sydney, Australia Purpose: Osteoarthritis (OA) is the most common joint disease in modern, aging societies and causes substantial physical and psychosocial disability. During the initiation and progression of OA, subchondral bone is the site of numerous dynamic morphological transformations due to an altered osteoblast metabolism, which is part of the pathological process. These in situ structural changes in subchondral bone can be readily observed using imaging techniques such as fat suppressed T2-weighted MRI during the course of OA. Whilst previous studies in the OA literature support a link between BMLs and knee pain, few have evaluated bone perfusion in relation to knee pain in OA. This study characterizes BML in OA by assessing perfusion in Ă subchondral bone with dynamic contrast-enhanced (DCE) MRI. Correlation of imaging parameters wasmadewith BML grade and size as well as WOMAC pain subscores. Methods: There were 37 participants with moderate to severe knee OA (mean 64.9 years, range 46 to 86) with radiographic Kellgren and Lawrencegradesof 3 and4. Themeanpain subscale of the Likert versionof the WOMAC index was 10.3 (0-20 scale). Subjects had an MRI performed of their knee on a 1.5T Twin Speed GE Excite scanner with a dedicated knee coil. BML localization was performed using a sagittal dual echo FSE fat suppressed sequencewithTR/TEof 4000ms/15ms, 60ms, 2.53mmslices, no skip/gap, 256X256matrix and 12 cm FOV. Each BMLwas graded from 0-3 on the basis of lesion size according to the BLOKS scoring system. Gadolinium-diethylenetriaminepenta -acetic acid (Gd-DTPA) was injected at a standard concentration (0.1 mmol/kg) using a power injector followed by a saline flush. Dynamic contrast enhanced (DCE) MRI was performed using a 3D FSPGR sequence with 20 sagittal slices of 3 mm thickness over 7 minutes with a 7.5 second time resolution with a TR/TE of 5.5ms/2.9ms with a 12 degree flip angle and 256x128 matrix. Subchondral BMLs were identified on T2W fat suppressed images as discrete areas of increased signal adjacent to subcortical bone and used for DCE-MRI perfusion analysis. A pharmacokinetic model was used to analyze perfusion parameters using in-house software to model transfer rates into and out of the BMLs using adjacent areas of muscle as internal controls. The relation between perfusion and pain was evaluated using multivariate linear regression and its relationship with pain at night was performed using ordinal logistic regression separately after adjustment for BML grade, age, gender and BMI. Results: There was a significant correlation between BML kel /Muscle kel (rate of contrast elimination) and BML grade (p1⁄40.001/0.002 in uni/ multivariate analyses). No significant associationwas foundbetweenBML DCE-MRI perfusionparameters and pain or pain at night.Moreover, BMLs Grades 1 and2 had small volumes compared to the total joint volume and may not contribute to the overall knee pain. An inverse relationship was also foundbetweenpainatnightandBMLgradedetermined fromtheprecontrast T2W fat suppressed images (p