Femorotibial Compartment Research Articles

Rates and sensitivity of knee cartilage thickness loss in specific central reading radiographic strata from the osteoarthritis initiative

To compare the rate and sensitivity to change of quantitative cartilage thickness change with magnetic resonance imaging (MRI) across specific radiographic strata of knee osteoarthritis (KOA) from central expert readings of the Osteoarthritis Initiative (OAI). Specifically, we explored whether Kellgren Lawrence grade (KLG) 2 knees with radiographic joint space narrowing (JSN) displayed greater cartilage loss than those without JSN, and whether knees with medial JSN grade2 had greater loss than those with grade1. One-year femorotibial cartilage thickness change was obtained for 836 knees, 112 without, and 724 with definite radiographic KOA based on baseline site readings. The maximum subregional cartilage loss, and cartilage thickness change in the total femorotibial joint (FTJ) and medial femorotibial compartment (MFTC) were analyzed across different radiographic strata (central vs site readings). The maximum subregional rate of change was significantly greater in central_KLG2 knees with than in those without JSN (172 ± 152 vs 134 ± 100 μm; P = 0.03). In contrast, the rate did not differ significantly between central_KLG1 knees with and without JSN. MFTC cartilage loss in central_medial_grade2 JSN knees was substantially and significantly greater than in grade1 knees (-70 ± 159 vs -31 ± 126 μm; P = 0.02). For comparison, the loss in grade3 knees was -72 ± 122 μm. In KLG2 knees, presence of radiographic JSN was associated with significantly and substantially greater rates of subregional cartilage loss. Differentiating knees with mild vs moderate medial JSN, and definite radiographic OA knees with vs without JSN is important in predicting structural progression of KOA, and for planning clinical trials testing the efficacy of disease modifying drugs (DMOADs).

Longitudinal analysis of MR spin–spin relaxation times (T2) in medial femorotibial cartilage of adolescent vs mature athletes: dependence of deep and superficial zone properties on sex and age

Cartilage 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. Twenty 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). 16 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 < 0.01) and cMF (-1.3 ms; [-2.4, -0.3] ms; P < 0.05), without obvious differences between males and females. No significant change was observed in the superficial layers, or in the deep or superficial layers of the mature athletes. In this first pilot study on quantitative imaging of cartilage maturation in healthy, athletic subjects, we find evidence of cartilage compositional change in deep cartilage layers of the medial femorotibial compartment in adolescents, most likely related to organizational changes in the collagen matrix.

Intraarticular sprifermin (recombinant human fibroblast growth factor 18) in knee osteoarthritis: a randomized, double-blind, placebo-controlled trial.

To evaluate the efficacy and safety of intraarticular sprifermin (recombinant human fibroblast growth factor 18) in the treatment of symptomatic knee osteoarthritis (OA). The study was a randomized, double-blind, placebo-controlled, proof-of-concept trial. Intraarticular sprifermin was evaluated at doses of 10 μg, 30 μg, and 100 μg. The primary efficacy end point was change in central medial femorotibial compartment cartilage thickness at 6 months and 12 months as determined using quantitative magnetic resonance imaging (qMRI). The primary safety end points were nature, incidence, and severity of local and systemic treatment-emergent adverse events (AEs) and acute inflammatory reactions, as well as results of laboratory assessments. Secondary end points included changes in total and compartment femorotibial cartilage thickness and volume as assessed by qMRI, changes in joint space width (JSW) seen on radiographs, and pain scores on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). One hundred ninety-two patients were randomized and evaluated for safety, 180 completed the trial, and 168 were evaluated for the primary efficacy end point. We found no statistically significant dose response in change in central medial femorotibial compartment cartilage thickness. Sprifermin was associated with statistically significant, dose-dependent reductions in loss of total and lateral femorotibial cartilage thickness and volume and in JSW narrowing in the lateral femorotibial compartment. All groups had improved WOMAC pain scores, with statistically significantly less improvement at 12 months in patients receiving the 100-μg dose of sprifermin as compared with those receiving placebo. There was no significant difference in serious AEs, treatment-emergent AEs, or acute inflammatory reactions between sprifermin and placebo groups. No statistically significant relationship between treatment group and reduction in central medial femorotibial compartment cartilage thickness was observed; however, prespecified structural secondary end points showed statistically significant dose-dependent reductions after sprifermin treatment. Sprifermin was not associated with any local or systemic safety concerns.

THU0195 Semiquantitatively Assessed Bone Marrow Lesions, Cartilage Damage, Meniscal Damage and Extrusion PREDICT Quantitatively Measured Cartilage Thickness Loss in the Same Femorotibial Compartment: the Most Study

BackgroundStudies have shown associations of structural progression of knee OA with several MRI-assessed pathologic features such as bone marrow lesions (BMLs) cartilage damage and meniscal lesions1,2. However previous studies commonly...

Cartilage damage, bone marrow lesions and meniscal lesions predict quantitatively measured loss of cartilage over 30-months: the most study

Cartilage damage, bone marrow lesions and meniscal lesions predict quantitatively measured loss of cartilage over 30-months: the most study

Changes in articular cartilage and posterior meniscus geometries after anterior cruciate ligament injury

Changes in articular cartilage and posterior meniscus geometries after anterior cruciate ligament injury

Extracellular matrix changes in response to recombinant human fibroblast growth factor 18 studied in ex vivo cultures of articular cartilage

Extracellular matrix changes in response to recombinant human fibroblast growth factor 18 studied in ex vivo cultures of articular cartilage

A flat all-polyethylene tibial component in medial unicompartmental knee arthroplasty: a long-term study

The aim of this study is to present the clinical and radiological results of a cemented unicompartmental knee arthroplasty (UKA) using a flat all-polyethylene tibial component at long-term follow-up, in a homogeneous group of patients with medial femoro-tibial knee arthritis. The study group included 53 knees in 51 patients who were treated between January 1998 and November 1999 using a flat all-polyethylene tibial component. The same surgical technique was used for all patients. Inclusion criteria included a diagnosis of atraumatic arthritis, pre-operative flexion greater than 100° with no flexion deformity, a varus deformity of less than 10°, and a body mass index (BMI) less than 35. A neutral mechanical axis was considered the end-point in all interventions. The patients were assessed clinically using the International Knee Society (IKS) and the functional scores at follow-up. Plain radiographs were used to determine the alignment of the mechanical axis at 5, 10 and 14.7-year follow-up. A radiographic analysis of loosening, based on the method described by the IKS, was performed and the degree of arthritic progression in the non-resurfaced compartment was also assessed. At latest follow-up five patients had died and the data for three patients had not been collected. At final review four knees had undergone revision surgery and a further patient had declined a recommended revision TKA. The main indication for revision surgery was progressive aseptic loosening of the tibial component in female patients. No revisions were required because of arthritic progression in the lateral compartment. Over time the clinical outcomes did not show statistically significant differences. There was a significant worsening of the mechanical axis at the last follow-up compared with the results at five and ten year review. This study demonstrated that, in primary arthritis involving the medial femoro-tibial compartment, UKA using a flat all-polyethylene component could be considered an effective surgical option. Attention should be paid to progressive worsening of the mechanical axis over time associated with progressive radiolucency especially in female patients. IV.

Lateral and medial joint space narrowing predict subsequent cartilage loss in the narrowed, but not in the non-narrowed femorotibial compartment – data from the Osteoarthritis Initiative

To determine the predictive value of unicompartimental joint space narrowing (JSN) for MRI-based cartilage thickness loss in the narrowed and the non-narrowed femorotibial compartment. 922 knees from 922 Osteoarthritis Initiative (OAI) participants (62.2 ± 9.0 years, 61% females) with radiographic OA (158 without JSN [noJSN], 175 with lateral JSN [latJSN], 589 with medial JSN [medJSN]) were analyzed using 3 T MRI. One-year cartilage thickness change was determined in the lateral (LFTC) and medial femorotibial compartment (MFTC), and in femorotibial subregions. The probability of subsequent cartilage loss was calculated using predefined thresholds. The predictive value of JSN for the probability and magnitude of cartilage loss was compared between latJSN, medJSN and noJSN knees using Fisher's exact and Mann-Whitney-U tests. The probability of cartilage loss was greater in the narrowed compartment of latJSN/medJSN knees (34.9%/32.4%) than in noJSN knees (13.3%/12.7%, P ≤ 6.4 × 10(-6)) and so was the magnitude of cartilage thickness change (P ≤ 8.2 × 10(-6)). No significant differences were observed between the narrowed compartments of latJSN vs. medJSN knees (probability: P = 0.58, magnitude: P = 0.19) or between the non-narrowed compartment of latJSN/medJSN vs. noJSN knees (probability: P ≥ 0.35, magnitude: P = ≥0.23). These results were confirmed by the location-independent ordered value (OV) analyses of femorotibial subregions. The predictive value of latJSN for lateral compartment cartilage loss was comparable to that of medJSN for medial compartment cartilage loss, whereas cartilage loss in the non-narrowed compartment was similar to that in noJSN knees. These findings provide important clues to predicting progression of knee OA, and in tailoring inclusion criteria for clinical trials.

Clinical and technical factors influencing outcomes of unicompartmental knee arthroplasty: Retrospective multicentre study of 944 knees

Unicompartmental knee arthroplasty (UKA) is reserved for osteoarthritis confined to a single femoro-tibial compartment with an intact anterior cruciate ligament. UKA remains controversial. The objective of this retrospective multicentre study in a large sample was to assess the influence of age, sex, body mass index (BMI), patellofemoral involvement, and implant design on functional outcomes and prosthesis survival rates. Nine hundred and forty-four patients who underwent UKA at centres located in western France between 1988 and 2008 were re-evaluated. The IKS scores and KOOS were determined. Prosthesis survival according to various factors was assessed using the Kaplan-Meier method. A clinical evaluation was performed in 720 cases after a mean follow-up of 62 months. The IKS function score improved by 23.6 points in men and 17.3 points in women (P=0.007). Ten-year prosthesis survival was 83.7% overall; 79% in women versus 87% in men (P<0.01); and 76.7% in patients younger than 70 years versus 88.3% in those 70 years or over (P<0.01). BMI had no significant influence on prosthesis survival. No significant differences between clinical outcomes or prosthesis survival were found across implant design categories. The retrospective design and large number of centres and surgeons mandate caution when interpreting our results. Subgroup sizes were too small for an analysis of factors such as anterior cruciate ligament deficiency, BMI>40 kg/m(2), or cementless implant. Level IV, retrospective study.

Experimental osteoarthritis in rabbits: lesion progression

The aim of this study was to evaluate the progression of lesions in different stages of osteoarthritis (OA) experimental by radiography (RX), computed tomography (CT), macroscopic and histopathology, linking these different diagnostic methods, helped to provide information that helps the best time for the therapeutic approach. Four experimental periods were delineated at 3, 6, 9 and 12 weeks after induction of OA, known as PI, PII, PIII and PIV, respectively, each with six animals. We evaluated the five compartments of the femorotibial joint: medial femoral condyle (MFC), lateral femoral condyle (LFC), medial tibial plateau (MTP), lateral tibial plateau (LTP) and femoral trochlea (FT). Therefore we established an index by compartment (IC) and by adding such an index was estimated joint femorotibial (IFT). It was observed that the CFM was the compartment with the highest IC also differed significantly (p&lt;0.05) from other compartments. Compartments showed no significant difference (p&gt;0.05) between the PI and PII, however contrary fact occurred between the PII and PIII (p&lt;0.05), PIII and PIV (p&lt;0.01) and between PI and PIV (p&lt;0.001). Similarly the IFT, showed a significant difference in the animals of PIV compared to PI (p&lt;0.001), PII (p&lt;0.001) and PIII (p&lt;0.01), and there was no statistical difference (p&gt; 0.05) between the PI and PII. In the variation of the average interval between periods, there was a higher value between the PIII PIV and for the other intervals of time periods (PI, PII, and PIII-PII). However, these intervals showed no statistically significant difference (p&gt;0.05). Through the RX, CT, macroscopic and histopathological findings, we found similar patterns among individuals within the same period demonstrating a gradual progression of the disease. These results show that between 3 and 6 weeks progression of the lesion is slower and probably also can be reversed in comparison to other ranges where proved further progression between 9 and 12 weeks after induction of trauma OA. These results may provide a better therapeutic approach aimed at reversing the lesions in early stages of OA. We conclude that the interconnection of the four diagnostic methods individually classified into scores, which were unified in both indices in the evaluation by the femorotibial joint compartment and may represent a diagnostic condition closer to the true condition of the injury and its progression.

Chondrocalcinosis of Femoro-Tibial and Proximal Tibio-Fibular Joints in Cadaveric Specimens: A High-Resolution CT Imaging Study of the Calcification Distribution

ObjectivesTo analyze calcium deposits by computed tomography (CT) in femoro-tibial compartments and proximal tibio-fibular joints; to assess the relationship with CT-assessed osteoarthritis (OA).Methods68 (34 pairs) cadaveric knees (mean age of 84) were scanned at high resolution CT. Menisci and hyaline cartilage calcifications in the femoro-tibial and proximal tibio-fibular joints were analyzed. OA was CT-assessed by the Kellgren and Lawrence score. Gross appearance of OA was evaluated on 29 left knees after dissection and India ink staining of tibial plateaus.ResultsIn femoro-tibial joints, meniscal calcifications (MC) and hyaline cartilage calcifications (HCC) were detected in 23(34%) and 14(21%) knees respectively. Calcifications mainly involved the three meniscal segments and were mainly observed in all thirds of the femoro-tibial compartments. In proximal tibio-fibular joints, HCC were detected in 19(28%) knees. The association HCC-MC in femoro-tibial joints and between calcifications in femoro-tibial and proximal tibio-fibular joints was strong (p<0.0001). Femoro-tibial and proximal tibio-fibular CT-assessed OA were respectively found in 23(34%) and 19(28%) knees. HCC were significantly associated with femoro-tibial OA (p = 0.04) while MC were not (p = 0.34). OA macroscopic evaluation showed a mean surface of cartilage lesions of 35% (range 0.13–0.55). No significant difference was demonstrated regarding the CT-detection of MC, HCC or CT-assessed OA.ConclusionsThis is the first study to report a strong association of chondrocalcinosis between femoro-tibial and tibio-fibular joints in addition to a strong association between MC and HCC in femoro-tibial compartments. No significant relationship between chondrocalcinosis and OA was demonstrated.

Revisiting spatial distribution and biochemical composition of calcium-containing crystals in human osteoarthritic articular cartilage

IntroductionCalcium-containing (CaC) crystals, including basic calcium phosphate (BCP) and calcium pyrophosphate dihydrate (CPP), are associated with destructive forms of osteoarthritis (OA). We assessed their distribution and biochemical and morphologic features in human knee OA cartilage.MethodsWe prospectively included 20 patients who underwent total knee replacement (TKR) for primary OA. CaC crystal characterization and identification involved Fourier-transform infra-red spectrometry and scanning electron microscopy of 8 to 10 cartilage zones of each knee, including medial and lateral femoral condyles and tibial plateaux and the intercondyle zone. Differential expression of genes involved in the mineralization process between cartilage with and without calcification was assessed in samples from 8 different patients by RT-PCR. Immunohistochemistry and histology studies were performed in 6 different patients.ResultsMean (SEM) age and body mass index of patients at the time of TKR was 74.6 (1.7) years and 28.1 (1.6) kg/m², respectively. Preoperative X-rays showed joint calcifications (chondrocalcinosis) in 4 cases only. The medial femoro-tibial compartment was the most severely affected in all cases, and mean (SEM) Kellgren-Lawrence score was 3.8 (0.1). All 20 OA cartilages showed CaC crystals. The mineral content represented 7.7% (8.1%) of the cartilage weight. All patients showed BCP crystals, which were associated with CPP crystals for 8 joints. CaC crystals were present in all knee joint compartments and in a mean of 4.6 (1.7) of the 8 studied areas. Crystal content was similar between superficial and deep layers and between medial and femoral compartments. BCP samples showed spherical structures, typical of biological apatite, and CPP samples showed rod-shaped or cubic structures. The expression of several genes involved in mineralization, including human homolog of progressive ankylosis, plasma-cell-membrane glycoprotein 1 and tissue-nonspecific alkaline phosphatase, was upregulated in OA chondrocytes isolated from CaC crystal-containing cartilages.ConclusionsCaC crystal deposition is a widespread phenomenon in human OA articular cartilage involving the entire knee cartilage including macroscopically normal and less weight-bearing zones. Cartilage calcification is associated with altered expression of genes involved in the mineralisation process.

Direct comparison of fixed flexion, radiography and MRI in knee osteoarthritis: responsiveness data from the Osteoarthritis Initiative

Minimum radiographic joint space width (mJSW) represents the Food and Drug Administration (FDA) standard for demonstrating structural therapeutic benefits for knee osteoarthritis (KOA), but only shows moderate responsiveness (sensitivity to change). We directly compare the responsiveness of magnetic resonance imaging (MRI)-based cartilage thickness and JSW measures from fixed-flexion radiography (FFR) and explore the correlation of region-matched changes between both methods. Nine hundred and sixty-seven knees of Osteoarthritis Initiative participants with radiographic KOA were studied: 445 over 1 year with coronal FLASH MRI and FFR, and 375/522 over 1/2 years with sagittal DESS MRI and FFR. Standardized response means (SRM) of cartilage thickness and mJSW were compared using the sign-test. With FLASH MRI, SRM was -0.28 for medial femorotibial compartment (MFTC) cartilage loss vs -0.15 for mJSW, and -0.32 vs -0.22 for the most sensitive MRI subregion (central MFTC) vs the most sensitive fixed-location JSW(x = 0.25). With DESS MRI, 1-year SRM was -0.34 for MFTC vs -0.22 for mJSW and -0.44 vs -0.28 for central MFTC vs JSW(x = 0.225). Over 2 years, the SRM was significantly greater for MFTC than for mJSW (-0.43 vs -0.31, P = 0.017) and for central MFTC than for JSW(x = 0.225) (-0.51 vs -0.44, P < 0.001). Correlations between changes in spatially matched MRI subregions and fixed-location JSW were not consistently higher (r = 0.10-0.51) than those between non-matched locations (r = 0.15-0.50). MRI displays greater responsiveness in KOA than JSW FFR-based JSW, with the greatest SRM observed in the central medial femorotibial compartment. Fixed-location radiographic measures appear not capable of determining the spatial distribution of femorotibial cartilage loss.

Quantitative MRI measures of cartilage predict knee replacement: a case–control study from the Osteoarthritis Initiative

ObjectiveKnee 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...

Double-Bundle Versus Single-Bundle Anterior Cruciate Ligament Reconstruction

Background: Surgical technique is essential in anterior cruciate ligament (ACL) reconstruction. Purpose: This randomized 5-year study tested the hypothesis that double-bundle ACL reconstruction with hamstring autografts and aperture screw fixation has fewer graft ruptures and rates of osteoarthritis (OA) and better stability than single-bundle reconstruction. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Ninety patients were randomized: double-bundle ACL reconstruction with bioabsorbable screw fixation (DB group; n = 30), single-bundle ACL reconstruction with bioabsorbable screw fixation (SBB group; n = 30), and single-bundle ACL reconstruction with metallic screw fixation (SBM group; n = 30). The following evaluation methods were used: clinical examination, KT-1000 arthrometer measurement, and International Knee Documentation Committee (IKDC) and Lysholm knee scores. Additionally, radiographic evaluation was made by a musculoskeletal radiologist who was unaware of the patients’ clinical and surgical data. A single orthopaedic surgeon performed all the operations, and clinical follow-up assessments were made in a blinded manner by an independent examiner. Results: Preoperatively, there were no differences between the groups. Eleven patients (7 in the SBB group, 3 in the SBM group, and 1 in the DB group) had a graft failure during the follow-up and went on to ACL revision surgery (P < .043). Of the remaining 79 patients, a 5-year follow-up was performed for 65 patients (20 in the DB group, 21 in the SBB group, and 24 in the SBM group) who had their grafts intact. At 5 years, there was no statistically significant difference in the pivot-shift or KT-1000 arthrometer tests. In the DB group, 20% of the patients had OA in the medial femorotibial compartment and 10% in the lateral compartment, while the corresponding figures were 33% and 18% in the single-bundle groups, again an insignificant finding. Further, no significant group differences were found in the knee scores. Conclusion: The double-bundle surgery resulted in significantly fewer graft failures and subsequent revision ACL surgery than the single-bundle surgeries during the 5-year follow-up. Knee stability and OA rates were similar at 5 years. In view of the size of the groups, some caution should be exercised when interpreting the lack of difference in the secondary outcomes.

3-T MRI assessment of osteophyte formation in patients with unilateral anterior cruciate ligament injury and reconstruction

To define the number and distribution of osteophytes (OPs) in bilateral knee MRI (magnetic resonance imaging) of patients with unilateral anterior cruciate ligament (ACL) rupture. Bilateral knee MRIs of 20 patients with unilateral ACL rupture and reconstruction were retrospectively analyzed for OPs. OPs were graded following the KOSS (knee OA scoring system) classification and their compartmental distribution was assessed following the WORMS (Whole-Organ Magnetic Resonance Imaging Score) classification. All examined knees revealed OPs. Knees with ACL rupture showed significant (p < 0.001) higher total numbers of OPs (mean 11.6; SD ± 4.4) than knees with intact ACL (mean 5.1; SD ± 2.3). Knees with ACL rupture showed increased OP formation in all knee compartments with predominance of marginal OPs in the lateral femorotibial compartment especially on the tibia. Our results show that after knee injury with ACL rupture and reconstruction, all knee compartments were involved in post-traumatic increase of OP formation. The most affected compartment was the lateral femorotibial compartment on the tibial side.

Role of glucosamine in the treatment for osteoarthritis

Over the last 20 years, several studies have investigated the ability of glucosamine sulfate to improve the symptoms (pain and function) and to delay the structural progression of osteoarthritis. There is now a large, convergent body of evidence that glucosamine sulfate, given at a daily oral dose of 1,500 mg, is able to significantly reduce the symptoms of osteoarthritis in the lower limbs. This dose of glucosamine sulfate has also been shown, in two independent studies, to prevent the joint space narrowing observed at the femorotibial compartment in patients with mild-to-moderate knee osteoarthritis. This effect also translated into a 50 % reduction in the incidence of osteoarthritis-related surgery of the lower limbs during a 5-year period following the withdrawal of the treatment. Some discrepancies have been described between the results of studies performed with a patent-protected formulation of glucosamine sulfate distributed as a drug and those having used glucosamine preparations purchased from global suppliers, packaged, and sold over-the-counter as nutritional supplements.

Association of frequent knee bending activity with focal knee lesions detected with 3T MRI over a period of 3 years- data from the osteoarthritis initiative

s / Osteoarthritis and Cartilage 20 (2012) S54–S296 S213 those with medial JSN (Table 1), and OV1 was significantly greater in knees with lateral than medial JSN1 in the FLASH sample (p1⁄40.001). Conclusions: Lateral uni-compartmental JSN is a strong predictor of cartilage loss in the lateral (but notmedial) femorotibial compartment, and medial uni-compartmental JSN is a strong predictor of cartilage loss in the medial (but not lateral) femorotibial compartment. The rate of lateral cartilage thickness loss in knees with lateral JSN was at least as great as that of medial cartilage loss in knees with the same medial JSN grade. This makes it attractive to enrich OA study populations with knees displaying lateral JSN, also in view of greater generalizability of results and potential treatment effects. In mixed cohorts with medial and lateral JSN, OV1 represents a uniform endpoint that can capture rates of change independent of the location. 424 ASSOCIATION OF FREQUENT KNEE BENDING ACTIVITY WITH FOCAL KNEE LESIONS DETECTED WITH 3T MRI OVER A PERIOD OF 3 YEARSDATA FROM THE OSTEOARTHRITIS INITIATIVE H. Alizai , W. Virayavanich , W. Lin , L. Nardo , M.C. Nevitt , J.A. Lynch , C.E. McCulloch , T.M. Link . Univ. of CaliforniaSan Francisco, San Francisco, CA, USA; Ramathibodi Hosp., Mahidol Univ., Bangkok, Thailand Purpose: To evaluate the association of frequent knee bending activities with the prevalence and progression of cartilage and meniscal abnormalities over a period of 3 years assessed with 3 Tesla (3T) MRI and to determine the effect of frequent knee bending on the different compartments of the knee. Materials and Methods: We recruited 115 subjects without radiographic knee osteoarthritis (OA) but with risk factors for OA from the Osteoarthritis Initiative (OAI) database. The inclusion criteria were: (1) age 45-55 years old, (2) body mass index (BMI) of 19-27 kg/m2, (3) Western Ontario and McMaster University (WOMAC) pain score of zero at baseline. Cartilage and meniscal abnormalities were graded on 3T MRI studies using the Whole-Organ MRI Score (WORMS). A self-reported questionnaire of knee bending activities (kneeling, squatting, stair climbing, and weight lifting) was completed at the initial visit. Logistic regression was used to determine the association of frequent knee bending activity with cartilage and meniscal abnormalities and odds ratios (OR) were calculated. Results: Frequent knee bending activities were associated with an increased risk of prevalent cartilage lesions (OR 3.63, 95%CI 1.39-9.52), in particular in the patellofemoral compartment (OR 3.09, 95%CI 1.22-7.79). The increase in risk associated with frequent knee bending was higher in subjects involved in two or more knee bending activities. At 3-year followup, individuals with frequent knee bending activities had higher progression of cartilage (OR 4.12, 95%CI 1.27-13.36) and meniscal abnormalities (OR 4.34, 95%CI 1.16-16.32). Conclusion: Frequent knee bending activities were associated with higher prevalence and progression of knee cartilage lesions in asymptomatic middle-aged subject, in particular at the patellofemoral compartment.

A study of the anatomy and injection techniques of the ovine stifle by positive contrast arthrography, computed tomography arthrography and gross anatomical dissection

Although ovine stifle models are commonly used to study osteoarthritis, meniscal pathology and cruciate ligament injuries and repair, there is little information about the anatomy of the joint or techniques for synovial injections. The objectives of this study were to improve anatomical knowledge of the synovial cavities of the ovine knee and to compare intra-articular injection techniques. Synovial cavities of 24 cadaver hind limbs from 12 adult sheep were investigated by intra-articular resin, positive-contrast arthrography, computed tomography (CT) arthrography and gross anatomical dissection. Communication between femoro-patellar, medial femoro-tibial and lateral femoro-tibial compartments occurred in all cases. The knee joint should be considered as one synovial structure with three communicating compartments. Several unreported features were observed, including a communication between the medial femoro-tibial and lateral femoro-tibial compartments and a latero-caudal recess of the lateral femoro-tibial compartment. No intermeniscal ligament was identified. CT was able to define many anatomical features of the stifle, including the anatomy of the tendinous synovial recess on the lateral aspect of the proximal tibia under the combined tendon of the peroneus tertius, extensor longus digitorum and extensor digiti III proprius. An approach for intra-articular injection into this recess (the subtendinous technique) was assessed and compared with the retropatellar and paraligamentous techniques. All three injection procedures were equally successful, but the subtendinous technique appeared to be most appropriate for synoviocentesis and for injections in therapeutic research protocols with less risk of damaging the articular cartilage.