Vastus Medialis Cross-sectional Area Research Articles

Morphological Differences of Knee Extensor Muscles Between Women With and Without Lateral Patellar Compression Syndrome

Background and Aims: The morphology of knee joint extensor muscles including vastus medialis (VM) and vastus lateralis (VL), is one of the important and effective factors in lateral patellar compression syndrome (LPCS). This study aims to examine the morphological differences of these knee extensor muscles between women with and without LPCS. Methods: In this causal-comparative study, 15 women with LPCS aged 18-30 years and 15 women without LPCS as controls participated who were selected by a convenience sampling methhod. For muscle imaging, the anteromedial (VM) and anterolateral (VL) thigh distal ends were scanned by using a two-dimensional digital ultrasound device (SonoSite Co., USA). The muscles’ cross-sectional area at the patellar base was measured in square centimeters and the muscle-fiber pennation angles of these muscles was measured in degree. Independent t-test was used to compare the variables between the two groups. The significance level was set at 0.05. Results: The cross-sectional area of VM in the control group was significantly higher than in the LPCS group (P=0.001), while the cross sectional area of VL was not significantly different between the two groups (P>0.05). The muscle-fiber pennation angle of VM in the LPCS group was significantly lower than in the control group (P=0.016), while the muscle-fiber pennation angles of VL in the LPCS group was significantly higher than in the control group (P=0.021). Conclusion: The morphology of VM and VL in women with LPCS symptoms shows a significant muscle imbalance that can change the patella position from normal to a more lateral position and increase the contact between the lateral facet of the patella and the lateral femoral condyle, resulting in increased pressure on this area and eventually knee pain.Muscle morphology, Cross-sectional area, Muscle-fiber pennation angle, Lateral patellar compression syndrome, Knee extensors

Knee Muscles Composition Using Electrical Impedance Myography and Magnetic Resonance Imaging.

We evaluated the correlation of electrical impedance myography (EIM) measurements of knee muscles composition using Skulpt ChiselTM with MRI data retrieved from muscles segmentation. A total of 140 patients (71 females, 52 ± 21 years) underwent knee MRI, EIM with Skulpt®, and clinical evaluation (SARC-F questionnaire). MRIs were reviewed to assess the cross-sectional area (CSA) and skeletal muscle index (SMI = CSA/height2) of vastus medialis, vastus lateralis, biceps, semimembranosus, and sartorius. We tested the correlations of EIM-derived parameters [body fat-percentage (BF%) and muscle quality] with total CSA, CSA of each muscle, SMI, and SARC-F scores (0–10) using Pearson correlation coefficient. We found medium negative correlation of BF% with SMI (r = −0.430, p < 0.001) and total CSA (r = −0.445, p < 0.001), particularly with biceps (r = −0.479, p < 0.001), sartorius (r = −0.440, p < 0.001), and semimembranosus (r = −0.357, p < 0.001). EIM-derived muscle quality showed small-to-medium positive correlation with MRI measurements, ranging from r = 0.234 of biceps (p = 0.006) to r = 0.302 of total CSA (p < 0.001), except for vastus lateralis (r = 0.014, p = 0.873). SARC-F scores showed small correlations with EIM and MRI data, ranging from r = −0.132 (p = 0.121) with EIM muscle quality to r = −0.288 (p = 0.001) with CSA of vastus medialis. Hence, we observed small-to-medium correlations of muscle parameters derived from Skulpt ChiselTM with SARC-F scores and MRI parameters. We recommend using Skulpt ChiselTM with caution for assessing knee skeletal muscles composition.

Effect of atorvastatin on skeletal muscles of patients with knee osteoarthritis: Post-hoc analysis of a randomised controlled trial.

ObjectivePopulations with knee osteoarthritis (KOA) are at increased risk of cardiovascular disease, due to higher prevalence of risk factors including dyslipidaemia, where statins are commonly prescribed. However, the effect of statins on muscles and symptoms in this population is unknown. Thus, this study examined the effect of atorvastatin on muscle properties in patients with symptomatic KOA.DesignPost-hoc analysis of a 2-year multicentre randomised, double-blind, placebo-controlled trial.SettingAustralian community.ParticipantsParticipants aged 40–70 years (mean age 55.7 years, 55.6% female) with KOA who met the American College of Rheumatology clinical criteria received atorvastatin 40 mg daily (n = 151) or placebo (n = 153).Main outcome measuresLevels of creatinine kinase (CK), aspartate transaminase (AST), and alanine transaminase (ALT) at 1, 6, 12, and 24 months; muscle strength (by dynamometry) at 12 and 24 months; vastus medialis cross-sectional area (CSA) on magnetic resonance imaging at 24 months; and self-reported myalgia.ResultsThere were no significant between-group differences in CK and AST at all timespoints. The atorvastatin group had higher ALT than placebo group at 1 (median 26 vs. 21, p = 0.004) and 6 (25 vs. 22, p = 0.007) months without significant between-group differences at 12 and 24 months. Muscle strength increased in both groups at 24 months without between-group differences [mean 8.2 (95% CI 3.5, 12.9) vs. 5.9 (1.3, 10.4), p = 0.49]. Change in vastus medialis CSA at 24 months favoured the atorvastatin group [0.11 (−0.10, 0.31) vs. −0.23 (−0.43, −0.03), p = 0.02] but of uncertain clinical significance. There was a trend for more myalgia in the atorvastatin group (8/151 vs. 2/153, p = 0.06) over 2 years, mostly occurring within 6 months (7/151 vs. 1/153, p = 0.04).ConclusionsIn those with symptomatic KOA, despite a trend for more myalgia, there was no clear evidence of an adverse effect of atorvastatin on muscles, including those most relevant to knee joint health.

Vastus medialis intramuscular fat is associated with reduced quadriceps strength, but not knee osteoarthritis severity

BackgroundVastus medialis intramuscular fat has been proposed to be a modifiable determinant of knee cartilage loss in patients with knee osteoarthritis. The objective was to determine whether vastus medialis intramuscular fat relates to osteoarthritis severity and quadriceps muscle strength in patients with non-traumatic and post-traumatic knee osteoarthritis. MethodsFor this cross-sectional study, participants with knee osteoarthritis were classified into two groups: non-traumatic (n = 22; mean age = 60 years) and post-traumatic (n = 19; mean age = 56 years). Healthy adults were included (n = 22; mean age = 59 years). A 3-Tesla magnetic resonance imaging was used to measure vastus medialis cross-sectional area and intramuscular fat. Isometric knee extensor muscle torque was assessed using an isokinetic dynamometer and normalized to body mass (Nm/kg). Knee osteoarthritis severity was assessed using standing antero-posterior radiographs (Kellgren-Lawrence scores). Regression analyses examined relationships between 1) vastus medialis intramuscular fat with knee osteoarthritis severity and osteoarthritis group, after accounting for sex and body mass index, and 2) knee extensor muscle torque with vastus medialis intramuscular fat, after accounting for sex and vastus medialis cross-sectional area. FindingsVastus medialis intramuscular fat was positively associated with body mass index (B = 0.321, P < 0.001), but not with osteoarthritis severity or group (P > 0.05). Higher vastus medialis intramuscular fat was associated with reduced knee extensor muscle torque (B = -0.040, P = 0.018). InterpretationGreater vastus medialis intramuscular fat was associated with lower quadriceps muscle strength in patients with knee OA. It is unclear whether this is due to the accumulation of vastus medialis intramuscular fat or other potential factors, such as diet and physical inactivity.

Quadriceps femoris cross-sectional area and specific leg strength: relationship between different muscles and squat variations.

BackgroundThe aim was to determine the relationship between the cross-sectional area of the quadriceps femoris and strength performance in the deep and parallel barbell squat.MethodsThe sample included 16 university students (seven female, 24.1 ± 1.7 years). Muscle strength was expressed as external load, including the one-repetition maximum and the body mass segments involved (calculated according to Dempster’s method). The cross-sectional area of the quadriceps femoris muscles was determined using ultrasound, while leg muscle mass was measured using the Bioelectrical Impedance method.ResultsThe cross-sectional areas of the three vastii muscles and leg muscle mass showed moderate to strong correlation with external load in both squat types (r = 0.509–0.873). However, partial correlation (cross-sectional area of quadriceps femoris muscles were controlled) showed significant association only between leg muscle mass and deep squat (r = 0.64, p < 0.05). The cross-sectional area of the vastus lateralis showed a slightly higher correlation with external load in the parallel than in the deep squat (r = 0.67, p < 0.01 vs. r = 0.59, p < 0.05). The regression analysis extracted the vastus medialis cross-sectional area as the most important factor in manifesting strength (parallel squat: R2 = 0.569; deep squat: R2 = 0.499, both p < 0.01). The obtained results suggest that parallel squat strength depends mainly on the cross-sectional area of the vastii muscles, while it seems that the performance in the deep squat requires an additional engagement of the hip and back extensor muscle groups.

Correlates of vastus medialis cross-sectional area in adults with symptomatic knee osteoarthritis

Purpose: Knee osteoarthritis is a common chronic joint disease affecting the whole joint. There is some evidence that increased quadriceps strength and muscle cross-sectional area (CSA) may help alleviate symptoms and slow disease progression, but the data is inconclusive. The aim of the study was to examine (1) the association between vastus medialis CSA and tibial cartilage volume cross-sectionally and longitudinally over 2 years, and (2) the association between vastus medialis CSA and knee pain and function cross-sectionally and longitudinally over 2 years, in individuals with symptomatic knee osteoarthritis.

Atrophy of individual thigh muscles measured by MRI in older adults with knee osteoarthritis: A cross-sectional study.

The characteristics of thigh-muscle cross-sectional area (CSA) in older adults with knee osteoarthritis (KOA) remain controversial. This study aimed to evaluate atrophy of individual thigh muscles in older adults with KOA and to determine which muscle CSA should be measured to detect KOA-related muscle atrophy of the thigh. In older adults, individual thigh-muscle CSA measured by 1.5 Tesla MRI was analyzed at 5% intervals of the femoral length (FL) around the mid-thigh between the proximal 25% of the FL and the distal 25%. Participants with KOA grade≤1 and grade≥2 were compared for ratios of quadriceps muscle (QM) CSA to total thigh, individual QM CSA to QM, and individual hamstring (HAM) CSA to HAM at 5% intervals. We included 40 older adults [20 males; mean (SD) age 73.3 (4.7) years; 20 with KOA grade≤1 and 20 with KOA grade≥2]. The ratio of vastus medialis (VM) CSA to QM from the proximal 25% to distal 15% and the ratio of semi-membranosus (SM) CSA to HAM at the distal 10% to 25% were significantly lower with KOA grade≥2 than grade≤1; the effect sizes were 0.34 to 0.67 for VM and 0.40 to 0.60 for SM. The effect sizes were greatest for the ratios of VM CSA to QM at the mid-thigh with 5% intervals and the ratio of SM CSA to HAM at the distal 25%. The ratio of VM CSA to QM and/or that of SM CSA to HAM were low and were the best indicators to detect KOA-related muscle atrophy of the thigh. However, to detect KOA-related muscle atrophy, the VM CSA ratio should be analyzed in the thigh region around the mid-thigh, whereas the SM CSA ratio should be analyzed in the thigh region at the muscle belly.

Role of thigh muscle cross-sectional area and strength in progression of knee cartilage degeneration over 48 months – data from the Osteoarthritis Initiative

To determine in a 48-month longitudinal study the association of thigh muscle cross-sectional area (CSA) and strength on progression of morphologic knee cartilage degeneration using 3T magnetic resonance imaging (MRI). Seventy Osteoarthritis Initiative (OAI) subjects aged 50-60 years, with no radiographic evidence of osteoarthritis (OA) and constant muscle strength over 48 months as measured by isometric knee extension testing were included. Baseline right thigh muscle CSAs were assessed on axial T1-weighted magnetic resonance (MR) images, and extensor to flexor CSA ratios were calculated. Degenerative knee abnormalities at baseline and 48-months were graded on right knee 3T MRIs using a modified whole organ MRI score (WORMS). Statistical analysis employed Student's t-tests and multivariable regression models adjusted for age, body mass index and gender. Extension strength was significantly and positively correlated with baseline thigh muscle CSA (r=0.65, P<0.001). Greater baseline total thigh muscle CSA was significantly associated with increase of cartilage WORMS scores over 48 months in patellar (P=0.027) and trochlear (P=0.038) compartments, but not in other knee compartments. Among specific muscle groups, CSA of extensors (P=0.021) and vastus medialis (VM) (P=0.047) were associated with patellar cartilage increase in WORMS. Baseline E/F ratio had a significant positive association with patellar WORMS cartilage score increase over 48 months, P=0.0015. There were no other significant associations between muscle CSA/ratios and increase in WORMS scores. Maintenance of proper extensor to flexor muscle balance about the knee through decreased E/F ratios may slow patellofemoral cartilage deterioration, while higher extensor and VM CSA may increase patellofemoral cartilage loss.

Factors associated with magnetic resonance imaging defined patellar tendinopathy in community-based middle-aged women: a prospective cohort study.

BackgroundPatellar tendinopathy identified by imaging modalities has been reported in asymptomatic athletes and associated with tendon-related symptoms. However there is little data in community-based populations. The aim of this cohort study was to examine the prevalence of magnetic resonance imaging (MRI) defined patellar tendinopathy, the factors associated with this condition, and whether it was associated with knee pain in community-based middle-aged women.MethodsOne hundred seventy six women, aged 40–67 years, with no significant knee pain or injury underwent knee MRI. Patellar tendinopathy was defined on both T1- and T2-weighted fat-saturated MRIs. The cross-sectional area of vastus medialis was measured from MRI. Height and weight were measured to calculate body mass index (BMI). Physical activity was assessed using a questionnaire. Knee pain was assessed using the Western Ontario and McMaster University Osteoarthritis Index.ResultsThe prevalence of MRI defined patellar tendinopathy was 30.1 %. Higher levels of physical activity (odds ratio 1.65, 95 % CI 1.09–2.51) and greater vastus medialis cross-sectional area (odds ratio 1.22, 95 % CI 1.04–1.43) were associated with increased prevalence of patellar tendinopathy, independent of age and BMI. The persistence of patellar tendinopathy was associated with the worsening of knee pain over 2 years (odds ratio 10.65, 95 % CI 1.14–99.77).ConclusionIn community-based middle-aged women MRI-diagnosed patellar tendinopathy is common, with higher levels of physical activity and greater vastus medialis size being risk factors suggesting a biomechanical effect. Persistent patellar tendinopathy is associated with worsening of knee pain. These findings suggest that further work is needed to determine the contribution of patellar tendinopathy on knee pain and function in older people.

THU0221 Pain Predicts Relatively Low Leg Muscle Mass in Knee Osteoarthritis

BackgroundLeg muscle mass is related to development and progression of knee OA, and some studies suggested low leg muscle mass quantified by cross-sectional images of CT or MRI was related...

Effect of Prehabilitation on the Outcome of Anterior Cruciate Ligament Reconstruction

Background: Prehabilitation is defined as preparing an individual to withstand a stressful event through enhancement of functional capacity. Hypothesis: We hypothesized that a preoperative exercise program would enhance postoperative outcomes after anterior cruciate ligament reconstruction (ACLR). Study Design: Randomized controlled clinical trial; Level of evidence, 1. Methods: Twenty volunteers awaiting ACLR were randomly assigned to a control or exercise intervention group. The exercise group completed a 6-week gym- and home-based exercise program. Assessments include single-legged hop test; quadriceps and hamstring peak torque and magnetic resonance imaging cross-sectional area (CSA); Modified Cincinnati Knee Rating System score; and muscle biopsy of the vastus lateralis muscle completed at baseline, preoperatively, and 12 weeks postoperatively. Myosin heavy chain (MHC) isoforms protein and messenger RNA (mRNA) expression were determined with SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis) and RT-PCR (real-time polymerase chain reaction), respectively; IGF-1 (insulin-like growth factor 1), MuRF-1 (muscle RING-finger protein-1), and MAFbx (muscle atrophy f-box) mRNA expression were determined with quantitative RT-PCR. Results: Following 6 weeks of exercise intervention, the single-legged hop test results improved significantly in the exercise-injured limb compared with baseline (P = .001). Quadriceps peak torque in the injured limb improved with similar gains in CSA compared with baseline (P = .001). However, this was not significantly increased compared with the control group. Quadriceps and vastus medialis CSA were also larger in the exercise group than in controls (P = .0024 and P = .015, respectively). The modified Cincinnati score was better in the exercise-injured limb compared with baseline. At 12 weeks postoperatively, the rate of decline in the single-legged hop test was reduced in the exercise group compared with controls (P = .001). Similar trends were not seen for quadriceps peak torque and CSA. The vastus medialis CSA had regressed to similar levels as the control group (P = .008). The modified Cincinnati score continued to increase in the exercise group compared with controls (P = .004). The expression of the hypertrophic IGF-1 gene was significantly increased after the exercise intervention (P = .028), with a decrease back to baseline 12 weeks postoperatively (P = .012). Atrophic MuRF-1 gene expression was decreased after intervention compared with baseline (P = .05) but increased again at 12 weeks postoperatively (P = .03). The MAFbx levels did not change significantly in either group and within each time point. On the mRNA level, there was a shift from MHC-IIx isoform to MHC-IIa after exercise, with significant changes compared with control preoperatively (P = .028). Protein testing was able to reproduce this increase for MHC-IIa isoform expression only. Conclusion: The 6-week progressive prehabilitation program for subjects undergoing ACLR led to improved knee function based on the single-legged hop test and self-reported assessment using the modified Cincinnati score. These effects were sustained at 12 weeks postoperatively. This study supports prehabilitation as a consideration for patients awaiting ACLR; however, further studies are warranted.

Quadriceps Muscle Atrophy After Anterior Cruciate Ligament Transection Involves Increased mRNA Levels of Atrogin-1, Muscle Ring Finger 1, and Myostatin

The aim of this study was to assess the mRNA levels of atrogin-1, muscle ring finger 1, and myostatin in rat quadriceps after anterior cruciate ligament (ACL) transection. Wistar rats were randomized into three different groups: ACL (surgery and ACL transection), sham (surgery without ACL transection), and control. Vastus medialis, rectus femoris, and vastus lateralis muscles were harvested at 1, 2, 3, 7, and 15 days after ACL transection. The mRNA levels of atrogin-1, muscle ring finger 1, and myostatin, as well as the ubiquitinated protein content, muscle mass, and cross-sectional area of the muscle fibers, were evaluated. Elevated levels of atrogin-1, muscle ring finger 1, and myostatin mRNA were detected in all tested muscles at most time points. The ubiquitinated protein content was increased at 3 days in the ACL and sham groups. The muscle mass of the ACL group was reduced at 3, 7, and 15 days (vastus lateralis and vastus medialis) and at 7 and 15 days (rectus femoris), whereas it was reduced in the sham group at 3 and 7 days (vastus lateralis and vastus medialis) and at 7 days (rectus femoris). The cross-sectional area of vastus medialis was reduced at 3, 7, and 15 days in the ACL group and at 3 and 7 days in the sham group. The cross-sectional area of the vastus lateralis was reduced at 7 and 15 days in the ACL group and at 7 days in the sham group. Whereas muscle mass and cross-sectional area recovery was noted in the sham group, no recovery was observed in the ACL group. Quadriceps atrophy after ACL transection involves increased levels of myostatin, atrogin-1, and muscle ring finger 1 mRNA and the accumulation of ubiquitinated protein.

Increase in vastus medialis cross‐sectional area is associated with reduced pain, cartilage loss, and joint replacement risk in knee osteoarthritis

Although there is evidence for a beneficial effect of increased quadriceps strength on knee symptoms, the effect on knee structure is unclear. We undertook this study to examine the relationship between change in vastus medialis cross-sectional area (CSA) and knee pain, tibial cartilage volume, and risk of knee replacement in subjects with symptomatic knee osteoarthritis (OA). One hundred seventeen subjects with symptomatic knee OA underwent magnetic resonance imaging of the knee at baseline and at 2 and 4.5 years. Vastus medialis CSA was measured at baseline and at 2 years. Tibial cartilage volume was measured at baseline and at 2 and 4.5 years. Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index at baseline and at 2 years. The frequency of knee joint replacement over 4 years was determined. Regression coefficients (B) and odds ratios were determined along with 95% confidence intervals (95% CIs). After adjusting for confounders, baseline vastus medialis CSA was inversely associated with current knee pain (r = -0.16, P = 0.04) and with medial tibial cartilage volume loss from baseline to 2 years (B coefficient -10.9 [95% CI -19.5, -2.3]), but not with baseline tibial cartilage volume. In addition, an increase in vastus medialis CSA from baseline to 2 years was associated with reduced knee pain over the same time period (r = 0.24, P = 0.007), reduced medial tibial cartilage loss from 2 to 4.5 years (B coefficient -16.8 [95% CI -28.9, -4.6]), and reduced risk of knee replacement over 4 years (odds ratio 0.61 [95% CI 0.40, 0.94]). In a population of patients with symptomatic knee OA, increased vastus medialis size was associated with reduced knee pain and beneficial structural changes at the knee, suggesting that management of knee pain and optimizing vastus medialis size are important in reducing OA progression and subsequent knee replacement.

Severity of comorbid osteoarthritis is not associated with increased risk for incident diabetes mellitus

s / Osteoarthritis and Cartilage 20 (2012) S54–S296 S187 Objective: Although there is evidence for a beneficial effect of increased quadriceps strength on knee symptoms, the effect on knee structure is unclear. This study examined the relationship between change in vastus medialis (VM) cross-sectional area (CSA) and knee pain, tibial cartilage volume and risk of knee replacement in subjects with symptomatic knee osteoarthritis (OA). Methods: 117 subjects with symptomatic knee OA had a knee MRI at baseline, 2 years, and 4.5 years. VM CSA was measured at baseline and 2 years. Tibial cartilage volume was measured at baseline, 2 years, and 4.5 years. Knee pain was assessed by the Western Ontario and McMaster University Osteoarthritis Index at baseline and 2 years. Knee joint replacement over 4 years was determined. Results: Baseline VM CSAwas inversely associated with current knee pain (r1⁄4-0.16, P1⁄40.04) andmedial tibial cartilage volume loss from baseline to 2 years (B1⁄4-11.2, 95% CI -20.1 to -2.4), but not baseline tibial cartilage volume. In addition, an increase in VM CSA from baseline to 2 years was associated with reduced knee pain over the same time period (r1⁄40.25, P1⁄40.01), reduced medial tibial cartilage loss from 2 to 4.5 years (B1⁄4-16.8, 95%CI -28.9 to -4.6), and reduced risk of knee replacement over 4 years (OR1⁄40.61, 95%CI 0.40-0.94). Conclusions: In a symptomatic knee OA population, increased VM size was associated with reduced knee pain and beneficial structural changes at the knee, suggestingmanagement of knee pain and optimizing VM size are important in reducing OA progression and subsequent knee replacement. 369 SEVERITY OF COMORBID OSTEOARTHRITIS IS NOT ASSOCIATED WITH INCREASED RISK FOR INCIDENT DIABETES MELLITUS G.A. Hawker , R. Croxford , A. Bierman , P. Harvey , L. Lipscombe . Women's Coll. Hosp., Toronto, ON, Canada; 2 Inst. For Clinical And Evaluative Sci., Toronto, ON, Canada; Univ. of Toronto,

Increase in vastus medialis cross-sectional area is associated with reduced pain, cartilage loss and joint replacement risk in knee osteoarthritis

Objective: Although there is evidence for a beneficial effect of increased quadriceps strength on knee symptoms, the effect on knee structure is unclear. We undertook this study to examine the relationship between change in vastus medialis cross-sectional area (CSA) and knee pain, tibial cartilage volume, and risk of knee replacement in subjects with symptomatic knee osteoarthritis (OA). Methods: One hundred seventeen subjects with symptomatic knee OA underwent magnetic resonance imaging of the knee at baseline and at 2 and 4.5 years. Vastus medialis CSA was measured at baseline and at 2 years. Tibial cartilage volume was measured at baseline and at 2 and 4.5 years. Knee pain was assessed by the Western Ontario and McMaster Universities Osteoarthritis Index at baseline and at 2 years. The frequency of knee joint replacement over 4 years was determined. Regression coefficients (B) and odds ratios were determined along with 95% confidence intervals (95% CIs). Results: After adjusting for confounders, baseline vastus medialis CSA was inversely associated with current knee pain ( r = −0.16, P = 0.04) and with medial tibial cartilage volume loss from baseline to 2 years (B coefficient −10.9 [95% CI −19.5, −2.3]), but not with baseline tibial cartilage volume. In addition, an increase in vastus medialis CSA from baseline to 2 years was associated with reduced knee pain over the same time period ( r = 0.24, P = 0.007), reduced medial tibial cartilage loss from 2 to 4.5 years (B coefficient −16.8 [95% CI −28.9, −4.6]), and reduced risk of knee replacement over 4 years (odds ratio 0.61 [95% CI 0.40, 0.94]). Conclusion: In a population of patients with symptomatic knee OA, increased vastus medialis size was associated with reduced knee pain and beneficial structural changes at the knee, suggesting that management of knee pain and optimizing vastus medialis size are important in reducing OA progression and subsequent knee replacement.

Neuromuscular electrical stimulation decrease atrogenes expresion after anterior cruciate ligament rupture on quadriceps muscle of rats

The aim of this study was to evaluate the effects of neuromuscular electrical stimulation (NMES) on quadriceps atrophy in the acute period after anterior cruciate ligament (ACL) rupture. We assessed the mRNA levels of atrogin-1 and MuRF1, and the cross sectional area (CSA) of vastus medialis (VM), rectus femoris (RF) and vastus lateralis (VL) muscles. Wistar rats were evaluated after 24h, 48h and 72h of ACL rupture, as follows: Control, Sham (surgery without ACL rupture), ACL (ACL ruptured), SE (sham treated with NMES) and ACLE (ACL treated with NMES). Muscle fiber CSA of VL reduced only in ACL after 72h, while VM decreased in both S and ACL groups after 72h compared to control values (p<0.05). Conversely, NMES increased CSA of VM in both SE and ACLE compared to ACL after 72h. MuRF1 and atrogin-1 mRNA levels increased in all muscles and periods investigated compared to control (p<0,05). Interestingly, NMES decreased the MuRF1 and atrogin-1 mRNA levels in the ACL and S groups in their respective period (p<0,05) as follow: 24h for both VM and VL; 48h for both VL and RF, and in 72h for VM, VL and RF. In conclusion, NMES reduced the accumulation of ubiquitin proteossome pathway genes in the majority of analyzed muscle and minimized the CSA reduction of VM in the acute period after ACL rupture or surgery procedure in quadriceps muscle of rats. JL Durigan has a Post-Doctoral fellowship provided by FAPESP (2008/09408-4).

Vastus medialis cross-sectional area is positively associated with patella cartilage and bone volumes in a pain-free community-based population

IntroductionAlthough vastus medialis and lateralis are important determinants of patellofemoral joint function, their relationship with patellofemoral joint structure is unknown. The aim of this study was to examine potential determinants of vastus medialis and lateralis cross-sectional areas and the relationship between the cross-sectional area and patella cartilage and bone volumes.MethodsTwo hundred ninety-seven healthy adult subjects had magnetic resonance imaging of their dominant knee. Vastus medialis and lateralis cross-sectional areas were measured 37.5 mm superior to the quadriceps tendon insertion at the proximal pole of the patella. Patella cartilage and bone volumes were measured from these images. Demographic data and participation in vigorous physical activity were assessed by questionnaire.ResultsThe determinants of increased vastus medialis and lateralis cross-sectional areas were older age (P ≤ 0.002), male gender (P < 0.001), and greater body mass index (P ≤ 0.07). Participation in vigorous physical activity was positively associated with vastus medialis cross-sectional area (regression coefficient [beta] 90.0; 95% confidence interval [CI] 38.2, 141.7) (P < 0.001) but not with vastus lateralis cross-sectional area (beta 10.1; 95% CI -18.1, 38.3) (P = 0.48). The cross-sectional area of vastus medialis only was positively associated with patella cartilage volume (beta 0.6; 95% CI 0.23, 0.94) (P = 0.001) and bone volume (beta 3.0; 95% CI 1.40, 4.68) (P < 0.001) after adjustment for potential confounders.ConclusionsOur results in a pain-free community-based population suggest that increased cross-sectional area of vastus medialis, which is associated with vigorous physical activity, and increased patella cartilage and bone volumes may benefit patellofemoral joint health and reduce the long-term risk of patellofemoral pathology.

Vastus medialis cross-sectional area is associated with patella cartilage defects and bone volume in healthy women

Although vastus medialis and vastus lateralis are important muscular determinants of patellofemoral joint function, it is unclear how these muscles relate to the structure of the patellofemoral joint. The aim of this cross-sectional study was to determine the relationship between the vasti muscles and patella cartilage volume and defects and patella bone volume. One hundred and seventy-five women, aged 40-67 years, with no knee pain or clinical lower-limb disease had magnetic resonance imaging (MRI) of their dominant knee. The cross-sectional areas of the distal vastus medialis and lateralis were measured 37.5mm superior to the quadriceps tendon insertion at the proximal pole of the patella. Patella cartilage volume and defects and patella bone volume were measured from these images using validated methods. There was no significant association between the distal vastus medialis cross-sectional area and patella cartilage volume. For every 1mm(2) increase in the distal vastus medialis cross-sectional area, there was an associated increased risk of patella cartilage defects [odds ratio (OR): 1.2; 95% confidence interval (CI) 1.004, 1.5; P=0.05], and an associated increase in patella bone volume (OR: 3.9; 95% CI 2.0, 5.8; P<0.001) after adjustment for potential confounders. There was no significant relationship between vastus lateralis cross-sectional area and measures of patella cartilage or bone. An increased cross-sectional area of the distal portion of the vastus medialis muscle is associated with an increased risk of patella cartilage defects, and an increase in patella bone volume among healthy women. Although these results need to be confirmed in longitudinal studies, they suggest that an increase in the distal vastus medialis cross-sectional area is associated with structural change at the patellofemoral joint.