Validity of the sonographic longitudinal sagittal image for assessment of the cartilage thickness in the knee osteoarthritis

Does vitamin D affect femoral cartilage thickness? An ultrasonographic study

This study aims to investigate the association between vitamin D levels and distal femoral cartilage thickness in healthy subjects. Eighty patients who were admitted to our outpatient clinic between May and July 2013 were classified into three subgroups according to their 25-OH vitamin D levels of <10, 10-20, and ≥20 ng/mL. Distal femoral cartilage thickness was measured from the midpoints of the right medial condyle (RMC), right lateral condyle (RLC), right intercondylar area (RIA), left medial condyle (LMC), left lateral condyle (LLC), and left intercondylar area (LIA) by using musculoskeletal ultrasound (US). The group with severe vitamin D deficiency (<10 ng/mL) had thinner femoral cartilage thickness at LMC (p = 0.005). Positive correlations were determined only between vitamin D levels and US measurements in the severe vitamin D deficiency group at RLC (r = 444, p = 0.020), LMC (r = 357, p = 0.067), and LLC (r = 568, p = 0.002). Low levels of vitamin D seem to affect the femoral cartilage thickness, adversely. Further studies are necessary to ascertain the clinical relevance of this change in cartilage thickness and whether vitamin D supplementation can reverse the cartilage thinning process or the allied clinical symptoms in the course of knee osteoarthritis.

Ultrasonographic evaluation in symptomatic knee osteoarthritis: clinical and radiological correlation

AIM

To explore the relationship among clinical, radiological and ultrasonographical findings in knee osteoarthritis (OA).

METHOD

Sixty-one patients (122 knees) with knee OA were enrolled. Patients' knees were classified into two groups according to symptom severity. Group I consisted of 61 more symptomatic knees and Group II comprised 61 less symptomatic knees. Subjects were clinically assessed for pain and functional status by using a visual analog scale and the Western Ontario and McMaster Universities Arthritis Index (WOMAC), respectively. Knee radiographs were evaluated by using the Kellgren-Lawrence (K-L) grading system. All knees were also evaluated ultrasonographically for meniscal bulging, distal femoral cartilage thickness, cartilage grading and also for the presence of effusion, Baker's cyst and so on.

RESULTS

Baker's cyst and joint effusion were observed more in Group I when compared with Group II. Positive correlations were found between meniscal bulging and all WOMAC scores (all P < 0.05). K-L grades of the patients were also positively correlated with WOMAC scores (all P < 0.05). Meniscal bulging measurements and K-L grades were positively correlated (P < 0.001). There was a negative correlation between cartilage grades and cartilage thickness measurements (all P < 0.001).

CONCLUSIONS

We found that joint space narrowing seemed to be associated with meniscal bulging. Moreover, increased meniscal bulging and presence of Baker's cyst/joint effusion were associated with worse pain or poorer function.

Measurement of articular cartilage thickness using a three-dimensional image reconstructed from B-mode ultrasonography mechanical scans feasibility study by comparison with MRI-derived data

The present study aimed to develop a method to measure three-dimensional (3-D) thickness of cartilage (Tc) at the femoral condyle using B-mode ultrasonography (US) and to clarify the feasibility of US in clinical evaluations of articular cartilage by comparing the results with 3-D measurement values using magnetic resonance imaging (MRI) and assessing repeatability. The medial surface of the right knees of two healthy male volunteers (age, 37 and 59 years) and the knees on affected side of three male patients with osteoarthritis (OA) (age, 73, 81 and 83 years) were scanned using B-mode US with the knee flexed at 120°. The range of the angle of probe rotation for the arm was 0-80° and B-mode images (total, 101 images) were acquired every 0.8°. MRI of the knees was also performed using the double echo steady-state sequence. Both US and MRI images were used to create 3-D models of medial femoral condyle articular cartilage. Tc was determined at points 1 mm apart from one another in the US model (Tc-US) and MRI model (Tc-MRI). Tc-US was compared with Tc-MRI and the repeatability of Tc-US was assessed by mean Tc in the specific region of interest of the femoral condyle. Tc-US correlated significantly with Tc-MRI both in volunteers and in OA patients (p < 0.0001 each) and coefficients of correlation were 0.976 and 0.964 for volunteers and OA patients, respectively. The coefficient of variance for mean Tc-US was 4.90%. Our results show that 3-D US measurements of femoral cartilage are reproducible and correlate strongly with MRI measurements.

Ultrasonic probe is useful for in vivo quantitative assessment of medial femoral condyle articular cartilage

PURPOSE

Although objective evaluation of articular cartilage is important for assessing the outcome of surgical treatment, no reliable method has yet been developed. It has recently been reported that quantitative ultrasound is applicable for assessment of living human cartilage. The purpose of this study was to investigate whether quantitative ultrasound is able to detect subtle changes in articular cartilage, as well as age-related changes in normal cartilage during arthroscopic surgery.

METHODS

Thirty-six patients with knee injury underwent ultrasonic evaluation of the articular cartilage during arthroscopy. The reflex echogram from the cartilage was converted to a wavelet map using wavelet transformation. As a quantitative index on the wavelet map, the maximum magnitude was selected. Whether or not the cartilage was damaged was judged from the arthroscopic view of the articular surface. Both normal sites (33 sites) and damaged areas (Outerbridge grade I-II, 11 sites) were measured.

RESULTS

The average maximum magnitude values for normal and damaged cartilage were 4.2 ± 1.6 and 1.4 ± 0.6, respectively. The maximum magnitude was significantly higher in intact, than in injured, cartilage (P < 0.01). The maximum magnitude for intact cartilage of the medial femoral condyle showed a significant correlation with patient age (r = -0.66, P < 0.01).

CONCLUSIONS

The present ultrasound measurement system offers potential for the detection of subtle change in cartilage. The maximum magnitude is particularly useful for quantitative assessment of medial femoral condyle articular cartilage. This ultrasound measurement system is useful for diagnosis of degenerative cartilage at an early stage.

Comparison of ultrasound speed in articular cartilage measured by different time-of-flight methods

The purpose of this study was to investigate whether different time-of-flight (TOF) methods including amplitude-related methods, which determine tissue borders from the reflected wave itself, and the cross-correlation method, which requires reference signals to determine borders, influence speed of sound (SOS) values for articular cartilage. Left femoral condyle samples from a 6-month-old pig and a 3-year-old pig were used. Radiofrequency signals from the cartilage surface and cartilage-bone interface were acquired using the ultrasound transducer for nine points in each sample. TOF was calculated by three amplitude-related methods (peak amplitude, peak envelope, signal phase) and a cross-correlation method. Cartilage thickness was measured microscopically, and SOS was calculated at each point. Mean (± standard deviation) SOSs in cartilage from the 9-point measurement by the four TOF methods were 1488 ± 51, 1488 ± 48, 1487 ± 54, and 1466 ± 51 m/s (for peak amplitude, peak envelope, signal phase, and cross-correlation methods, respectively) for the 6-month-old pig, and 1709 ± 107, 1717 ± 104, 1713 ± 105, and 1695 ± 138 m/s, respectively, for the 3-year-old pig. Paired t testing identified no significant differences between the amplitude-related methods and the cross-correlation method, although SOS values yielded by the amplitude-related methods tended to be higher than those from the cross-correlation method. These results suggest that amplitude-related methods of TOF measurement and the cross-correlation method are equivalently applicable to articular cartilage SOS measurement when a wave is clearly reflected from cartilage. TOF methods should thus be considered in studies on SOS measurement.

Sonographic evaluation of femoral trochlear cartilage in patients with knee pain

OBJECTIVES

The purpose of this study was to investigate whether routine clinical sonographic evaluation of femoral trochlear cartilage can identify abnormalities in patients with knee pain.

METHODS

Short-axis sonograms of the femoral trochlear cartilage were obtained from 20 symptomatic knees in 20 consecutive patients (16 women and 4 men; mean age, 54 years; range, 35-75 years) and 20 knees in 10 asymptomatic control participants (7 women and 3 men; mean age, 52 years; range, 31-74 years). Articular cartilage thickness was measured at 3 locations in each knee, and thickness at each site was compared between patients and controls. Subsequently, images from patients and controls were randomly assorted and evaluated by 3 blinded musculoskeletal radiologists, who independently evaluated the femoral trochlear cartilage in each sonogram for cartilage clarity, grade, and presence or absence of cartilage calcifications, osteophytes, and subchondral bony irregularity. The radiologists were instructed to rate the most severe lesion in each evaluated region (medial trochlea, trochlear notch, and lateral trochlea). Cartilage clarity was defined as how well the cartilage borders could be distinguished from the overlying intra-articular soft tissues, and grade was defined as the severity of focal cartilaginous lesions.

RESULTS

Using the Student t test, there was no significant difference (P > .05) between cartilage thickness in patients and controls for any location measured. However, using repeated measures analysis of variance, there were significant differences (P = .02) for both decreased cartilage clarity (df = 1/28; F = 5.76) and increased grade (df = 1/28; F = 5.77) in patients. There was also a nonsignificant (P > .05) trend toward more frequent calcifications, osteophytes, and bony irregularity in patients.

CONCLUSIONS

Routine clinical sonography can identify femoral trochlear cartilage abnormalities in patients with knee pain and therefore can be a useful adjunct to other imaging tests for identifying arthritic changes in the knee.

Reliability and validity of ultrasound imaging of features of knee osteoarthritis in the community

Background

Radiographs are the main outcome measure in epidemiological studies of osteoarthritis (OA). Ultrasound imaging has unique advantages in that it involves no ionising radiation, is easy to use and visualises soft tissue structures. Our objective was to measure the inter-rater reliability and validity of ultrasound imaging in the detection of features of knee OA.

Methods

Eighteen participants from a community cohort, had both knees scanned by two trained musculoskeletal sonographers, up to six weeks apart. Inter-rater reliability for osteophytes, effusion size and cartilage thickness was calculated by estimating Kappa (κ) and Intraclass correlation coefficients (ICC), as appropriate. A measure of construct validity was determined by estimating κ between the two imaging modalities in the detection of osteophytes.

Results

Reliability: κ for osteophyte presence was 0.77(right femur), 0.65(left femur) and 0.88 for both tibia. ICCs for effusion size were 0.70(right) and 0.85(left). Moderate to substantial agreement was found in cartilage thickness measurements. Validity: For osteophytes, κ was moderate to excellent at 0.52(right) and 0.75(left).

Conclusion

Substantial to excellent agreement was found between ultrasound observers for the presence of osteophytes and measurement of effusion size; it was moderate to substantial for femoral cartilage thickness. Moderate to substantial agreement was observed between ultrasound and radiographs for osteophyte presence.

Ultrasound biomicroscopy for the detection of early osteoarthritis in an animal model

RATIONALE AND OBJECTIVES

Osteoarthritis (OA) is a common disease, and early diagnosis is essential for preventing further cartilage destruction and decreasing severe complications. Ultrasound biomicroscopy (UBM) is sensitive for detecting minute lesions in tissue because of its higher resolution, but its B-mode characterization of the early stage of OA has not been widely studied. The aim of this study was to determine the usefulness of UBM for detecting the early stage of OA using a rabbit model of early OA.

MATERIALS AND METHODS

Eighteen adult New Zealand White female rabbits were used in this study, which included 12 rabbits that underwent transections of the left anterior cruciate ligament and six control rabbits. At 2, 4, and 6 weeks after surgery, four experimental rabbits and two control rabbits were euthanized. UBM was performed to evaluate the articular cartilage surfaces of the left knee, using a 55-MHz transducer. All the articular cartilage surfaces were independently assessed in blinded fashion by two radiologists for the severity of OA. The value of UBM, interobserver reliability, and the concordance between UBM and pathologic grades were determined.

RESULTS

For the first radiologist, the sensitivity, specificity, positive predictive value, and negative predictive value of UBM for the diagnosis of OA were 91%, 83%, 89%, and 86%, respectively. For the second radiologist, the sensitivity, specificity, positive predictive value, and negative predictive value of UBM were 93%, 86%, 91%, and 89%, respectively. The concordance between UBM and pathologic grades for both radiologists was high (κ = 0.72 and 0.76), and the interobserver agreement was high (κ = 0.80).

CONCLUSIONS

UBM can be used to evaluate cartilage defects in an animal model, and further study is needed to determine whether this technique can be valuable for detecting early OA in humans.