Ultrasound properties of articular cartilage in the tibio-femoral joint in knee osteoarthritis: relation to clinical assessment (International Cartilage Repair Society grade)

Femoral cartilage ultrasound echo-intensity is a valid measure of cartilage composition

This study aimed to create a conversion equation that accurately predicts cartilage magnetic resonance imaging (MRI) T2 relaxation times using ultrasound echo-intensity and common participant demographics. We recruited 15 participants with a primary anterior cruciate ligament reconstruction between the ages of 18 and 35 years at 1-5 years after surgery. A single investigator completed a transverse suprapatellar scan with the ACLR limb in max knee flexion to image the femoral trochlea cartilage. A single reader manually segmented the femoral cartilage cross-sectional area to assess the echo-intensity (i.e., mean gray-scale pixel value). At a separate visit, a T2 mapping sequence with the MRI beam set to an oblique angle was used to image the femoral trochlea cartilage. A single reader manually segmented the cartilage cross-sectional area on a single MRI slice to assess the T2 relaxation time. A stepwise, multiple linear regression was used to predict T2 relaxation time from cartilage echo-intensity and common demographic variables. We created a conversion equation using the regression betas and then used an ICC and Bland-Altman plot to assess agreement between the estimated and true T2 relaxation time. Cartilage ultrasound echo-intensity and age significantly predicted T2 relaxation time (F = 7.33, p = 0.008, R2 = 0.55). When using the new conversion equation to estimate T2 relaxation time from cartilage echo-intensity and age, there was strong agreement between the estimated and true T2 relaxation time (ICC2,k = 0.84). This study provides promising preliminary data that cartilage echo-intensity combined with age can be used as a clinically accessible tool for evaluating cartilage composition.

Utilizing MSK Ultrasound for Comprehensive Assessment of the Femoral Trochlea: A Game Changer in Sports Medicine

Musculoskeletal (MSK) ultrasound has emerged as a valuable tool for sports physical therapists in the assessment and treatment of various knee pathologies. Its ability to provide high-resolution images of soft tissue and superficial bone surfaces makes it especially useful for sports physical therapists and orthopedic clinicians. Specifically, MSK-ultrasound is increasingly recognized as a potent tool for the assessment of the femoral trochlea. Its non-invasive nature and dynamic imaging capabilities make it particularly suited for visualizing the femoral trochlea, a critical component in knee function and biomechanics. The use of MSK ultrasound in the evaluating the femoral trochlea provides sports medicine professionals with a dynamic, non-invasive, and cost-effective means to diagnose, and monitor knee-related injuries. This article delves into the utility of MSK ultrasound in the anatomical and functional assessment of the femoral trochlea, elucidating its benefits, limitations, and clinical implications for athletes.

Intraoperative Acoustic Evaluation of Living Human Knee Cartilage-Comparison with Respect to Cartilage Degeneration and Aging

OBJECTIVE

The objective of the study was to evaluate the mechanical properties of living human knee cartilage using our ultrasonic device, and to compare the measurements with respect to cartilage degeneration and aging.

DESIGN

A total of 95 knees which had undergone arthroscopic knee surgery, from 88 patients, were included in the study, with informed consent. All procedures were reviewed and approved by the ethical committee of our hospital. In the study group, there were 41 men, 47 women, 39 right knees, and 56 left knees. The conditions primarily included knee osteoarthritis and anterior cruciate ligament rupture. The mean operative age was 44.1 years old (range = 10-83). We compared mechanical properties of the knee cartilage with respect to aging and gender, in comparison with normal cartilage. A P value of <0.05 represented statistical significance.

RESULTS

In the context of the International Cartilage Repair Society (ICRS) classification of cartilage degeneration (grade 0-3), the signal intensity in grade 0 was significantly larger than that in grade 1, 2, or 3. The thickness in grade 0 was significantly higher than that in grade 1, 2, or 3. Normal cartilage in older women had the lowest signal intensity and the least cartilage thickness among all the groups.

CONCLUSION

The ultrasonic system we developed was able to detect early degenerative changes in living cartilage in knees. The lowest signal intensity and least cartilage thickness in normal cartilage among older women were correlated to a large prevalence of knee osteoarthritis in women.

LEVEL OF EVIDENCE

Level IV, case series.

Plantar pressure profile during walking is associated with talar cartilage characteristics in individuals with chronic ankle instability

BACKGROUND

Individuals with chronic ankle instability typically present with abnormal gait patterns favoring the lateral foot. This gait pattern may alter cartilage stress potentially increasing the risk of osteoarthritis development, thus exploring this relationship may provide insights for early interventions. The purpose of this study was to examine the relationship gait biomechanics and talar articular cartilage characteristics.

METHODS

Talar articular cartilage was assessed with ultrasound at rest and after walking for 30-min in twenty-five adults (14 females, 22.6 ± 3.12 years, 168.12 ± 9.83 cm, 76.00 ± 15.47 kg) with chronic ankle instability. Cartilage was segmented into Total, Medial, and Lateral regions. During the 30-min walking period, plantar pressure of the entire foot was recorded every 5-min and condensed to create a biomechanical loading pattern and center of pressure gait line. Relationships between resting cartilage thickness and echo intensity, changes in thickness and echo intensity, and plantar pressure profiles were assessed with correlation coefficients.

FINDINGS

There was a significant relationship between plantar pressure in the lateral forefoot and medial talar cartilage deformation (r = 0.408, p < .05). Early stance center of pressure was correlated with deformation in the total (r = 0.439-0.524) and lateral (r = 0.443-0.550) regions (p < .05). There were no significant correlations between echo intensity and biomechanics.

INTERPRETATION

This study contributes to the growing evidence that talar cartilage strain patterns are associated with biomechanics during walking. Further validation is needed to determine a causal relationship between biomechanics and ultrasound cartilage characteristics after ankle sprains. In addition, research should continue determining the utility of ultrasound to monitor joint health after musculoskeletal injuries.

The Oral Administration of Highly-Bioavailable Curcumin for One Year Has Clinical and Chondro-Protective Effects: A Randomized, Double-Blinded, Placebo-Controlled Prospective Study

Purpose

The purpose of this study was to determine the clinical and chondroprotective efficacy and safety of orally administered Theracurmin in patients who underwent mosaicplasty for knee chondral or osteochondral diseases over 12 months of treatment.

Methods

We enrolled 50 patients, older than 20 years of age, who underwent mosaicplasty for their knee joint diseases. Theracurmin at 180 mg of curcumin per day or placebo was administered orally every day for 12 months. Because 7 patients dropped out of the study, 43 patients were examined; they included 14 men and 29 women and 24 right and 19 left knees. The mean operative age was 59.5 years (range, 24-84 years). We evaluated the Japanese Orthopaedic Association knee osteoarthritis score (JOA), visual analog scale (VAS), and Japanese Knee Osteoarthritis Measure (JKOM) as clinical symptoms; T2 mapping values using magnetic resonance imaging as an indication of the chondroprotective effect; and blood concentration of curcumin at 0, 3, 6, and 12 months after the operations. We performed intraoperative acoustic evaluation of articular cartilage as a measure of chondroprotective effect during the operations and second-look arthroscopy.

Results

The JOA, VAS and JKOM at 3, 6, and 12 months were significantly better than those during the preoperative period. However, the values of JOA, VAS and JKOM and T2 mapping were not significantly different between the Theracurmin and placebo groups. The blood concentration of curcumin in the Theracurmin group was significantly higher than that in the placebo group at 3, 6, and 12 months after the operations. Cartilage stiffness and surface roughness were significantly better in the Theracurmin group than in the placebo group at second-look arthroscopy.

Conclusions

The oral administration of Theracurmin for 1 year demonstrated significantly better chondroprotective effects and no worse clinical effects and adverse events than the placebo.

Level of Evidence

Level I, double-blinded, placebo-controlled, prospective study.

Pre-Operative Femoral Cartilage Ultrasound Characteristics Are Altered in People Who Report Symptoms at 1 year After Anterior Cruciate Ligament Reconstruction

We assessed whether pre-operative femoral cartilage thickness and echo intensity on ultrasound are different between individuals who are symptomatic (n = 6) and asymptomatic (n = 7) at 1 year after a primary unilateral anterior cruciate ligament (ACL) reconstruction (age, 23 ± 4 y; 31% women, 69% men; body mass index, 24.9 ± 3.7 kg/m²). A pre-operative, bilateral ultrasound assessment was used to quantify average thickness and echo intensity in the medial, middle and lateral femoral trochlear regions. An inter-limb ratio (ACL/contralateral limb) was calculated for average thickness and echo intensity. At 1 y after ACL reconstruction, we operationally defined the presence of symptoms as scoring ≤85% on at least two Knee Injury and Osteoarthritis Outcome Score subscales. Independent-sample t-tests and Cohen's d effect sizes were used to compare ultrasound pre-operative inter-limb ratios between participants with and without symptoms at 1 y after ACL reconstruction. For medial femoral cartilage, symptomatic participants had significantly greater average cartilage thickness inter-limb ratios (p = 0.01, d = -1.65) and significantly lower echo intensity inter-limb ratios (p = 0.01, d = 1.72) compared with asymptomatic participants. Middle and lateral femoral cartilage average thickness and echo intensity were not different between symptomatic and asymptomatic participants. These findings provide preliminary evidence that a clinically feasible ultrasound assessment of the femoral trochlear cartilage may be prognostic of self-reported symptoms at 1 y after ACL reconstruction.

High-Frequency Acoustic Imaging Using Adhesive-Free Polymer Transducer

The piezoelectric polymer PVDF and its copolymers have a long history as transducer materials for medical and biological applications. An efficient use of these polymers can potentially both lower the production cost and offer an environment-friendly alternative for medical transducers which today is dominated by piezoelectric ceramics containing lead. The main goal of the current work has been to compare the image quality of a low-cost in-house transducers made from the copolymer P(VDF-TrFE) to a commercial PVDF transducer. Several test objects were explored with the transducers used in a scanning acoustic microscope, including a human articular cartilage sample, a coin surface, and an etched metal film with fine line structures. To evaluate the image quality, C- and B-scan images were obtained from the recorded time series, and compared in terms of resolution, SNR, point-spread function, and depth imaging capability. The investigation is believed to provide useful information about both the strengths and limitations of low-cost polymer transducers.

A Retrospective Analysis of Characteristic Features of Responders and Impaired Patients to a Single Injection of Pure Platelet-Rich Plasma in Knee Osteoarthritis

(1) Background: The emergence of injectable “biologic” medication creates a new approach to treat osteoarthritis (OA). Among them, the use of intra-articular injection of PRP became widespread despite the absence of consensus regarding its optimal composition. The aim of this study was to retrospectively correlate an extensive biological characterization of injected PRP to the clinical responses of patients presenting knee OA. (2) Methods: This retrospective study included 75 patients with knee OA. Cartilage lesions were assessed using magnetic resonance imaging and the International Cartilage Regeneration Society (ICRS) classification. PRP extensive biological characterization was performed and patients’ subjective symptoms were recorded before injection and 3 and 6 months after injection using the Knee injury and Osteoarthritis Outcome Score (KOOS). Responders were defined by an improvement of 10 points on KOOS. (3) Results: At 6 months, 63.0% of the patients were responders. Impairment was characterized by a significantly higher proportion of patients with three compartments altered at baseline MRI and receiving a significantly higher dose of platelets compared to responders. (4) Conclusions: Single injection of pure PRP resulted in significant clinical improvement in the management of knee OA. Both baseline MRI and PRP biological features may be predictive factors of the clinical response, highlighting that a better understanding of action mechanism of PRP is still required.

Femoral Cartilage Ultrasound Echo Intensity Associates with Arthroscopic Cartilage Damage

This study compared quantitative cartilage ultrasound metrics between people with (n = 12) and without (n = 12) arthroscopic cartilage damage after anterior cruciate ligament injury (age, 24.9 ± 3.7 y; sex, 33% female, 67% male; days since injury = 50 ± 52). A transverse suprapatellar ultrasound assessment imaged the femoral cartilage in participants' injured knees before a clinical arthroscopy. A custom program automatically separated a manual cartilage segmentation into standardized medial and lateral femoral regions and calculated mean thickness (i.e., cross-sectional area/length of cartilage-bone interface), mean echo intensity and echo-intensity heterogeneity. An orthopedic surgeon assessed arthroscopic cartilage damage in the medial and lateral femoral condyles using the Outerbridge grading system (cartilage damage = Outerbridge ≥ 1). Separate logistic regressions for medial and lateral femoral cartilage were used to determine the association between each ultrasound metric and arthroscopic cartilage damage. In medial femoral cartilage, for every 1 standard deviation decrease in echo-intensity mean and heterogeneity, there is, respectively, a 91% (adjusted odds ratio, 0.09; 95% confidence interval, 0.01-0.69) and 97% (adjusted odds ratio, 0.03; 95% confidence interval, 0.002-0.50) increase in the odds of having arthroscopic cartilage damage. Lateral cartilage ultrasound metrics are not associated with lateral arthroscopic cartilage damage. This study provides preliminary evidence that femoral cartilage ultrasound echo intensity is a non-invasive measure associated with medial femoral cartilage health after anterior cruciate ligament injury.

Quantitative Parameters for the Degeneration in Cartilage and Subchondral Bone of Human Knee by 3-D Ultrasound Scanning System

This study was aimed at investigating the use of ultrasound parameters obtained non-invasively through soft tissue (ST) to evaluate degeneration in cartilage and subchondral bone (SB) in the human knee. We developed a 3-D ultrasound system and introduced the ratio parameters R_cb and R_cbT to suppress the attenuation effect in the ST or in both the ST and cartilage. As reference measurements, the grade for cartilage by visual judgment (G_sum) and ultrasound parameters for the cartilage and the SB were directly evaluated under arthroscopy. R_cb correlated significantly with G_sum (r_s = -0.63) and with the corresponding parameter obtained directly under arthroscopy (r = 0.55). R_cbT also correlated significantly with G_sum (r_s = -0.46) but was not superior to R_cb. R_cb is considered to be an efficient parameter that reflects the total degeneration in both the cartilage and SB, including the information on cartilage thickness.

Sonography: a sensitive and specific method for detecting trochlear cartilage pathologies

PURPOSE

MRI is now the modality of choice for evaluating articular cartilage. Nevertheless, it has some general drawbacks. Some patients cannot undergo MRI, and in others US scan could be the first examination and cartilage should be evaluated. Ultrasound could be a useful method for detecting trochlear cartilage low-grade lesions. In this study, our goal was to evaluate the efficacy of ultrasonography in detecting these lesions.

METHODS

All patients referred to our hospital, from July 2018 to July 2019, who were arthroscopic candidates due to sport-related pathologies, underwent ultrasound scan 1 day prior to surgery. Ultrasound assessment was performed by an expert radiologist, with a 13-MHz probe, located transversely proximal to the patella in different degrees of knee flexion to assess trochlear lesion grade and thickness. Arthroscopic examination of all patients was performed by an experienced orthopedic knee surgeon (second author). Sensitivity and specificity of ultrasound were calculated.

RESULTS

A total of 48 patients were involved in the study with a mean age of 33.2 years (SD: 9.7), between 19 and 51 years of age. Patients were 81% male (39 patients). The sensitivity of ultrasound in grading of trochlear cartilage lesion was 100%, meanwhile its specificity was 88.2% (30 cases had normal cartilage while this figure was 34 in arthroscopy).

CONCLUSION

Sonography is a low-cost, accessible diagnostic tool with high sensitivity and specificity for early detection of trochlear cartilage pathologies. It can play an important role as an outpatient diagnostic workup in patients with anterior knee pain.

Therapeutic Potential Low-Intensity Pulsed Ultrasound for Osteoarthritis: Pre-clinical and Clinical Perspectives

Osteoarthritis (OA), degeneration of cartilage associated with aging, lifestyle, and trauma, is one of the most common diseases that leads to lower quality of life and socioeconomic burden in the United States. Clinically, OA is initially managed by non-steroidal anti-inflammatory drugs, but eventually requires surgical intervention to reduce pain and increase function. Cartilage is a mechanotransductive tissue and requires a mechanical stimulus to sustain its mechanical and physiologic properties. Low-intensity pulsed ultrasound (LIPUS) is a cyclic acoustic wave that can provide essential mechanical stimuli to activate molecular and cellular pathways leading to chondrocyte proliferation, differentiation and activity, as well as to inhibit inflammatory pathways associated with OA. The activation of chondrocyte proliferation and inhibition of anti-inflammatory cytokines make LIPUS a potential therapy for mild to moderate OA. Although a few review articles have described the effects of ultrasound on chondrocytes and cartilage, there remains a need for a comprehensive analysis of our current understanding of the basic science and clinical status of the effects of low-intensity ultrasound on chondrocytes and cartilage and the implications of these studies on LIPUS as a therapeutic option for OA. This review analyzes recent literature describing the results of LIPUS using in vitro and in vivo pre-clinical models and clinical studies, as well as future directions for research.

Relationships Between Quantitative Pulse-Echo Ultrasound Parameters from the Superficial Zone of the Human Articular Cartilage and Changes in Surface Roughness, Collagen Content or Collagen Orientation Caused by Early Degeneration

We aimed to quantitatively investigate the relationship between amplitude-based pulse-echo ultrasound parameters and early degeneration of the knee articular cartilage. Twenty samples from six human femoral condyles judged as grade 0 or 1 according to International Cartilage Repair Society grading were assessed using a 15-MHz pulsed-ultrasound 3-D scanning system ex vivo. Surface roughness (R_q), average collagen content (A₁) and collagen orientation (A₁₂) in the superficial zone of the cartilage were measured via laser microscopy and Fourier transform infrared imaging spectroscopy. Multiple regression analysis with a linear mixed-effects model (LMM) revealed that a time-domain reflection coefficient at the cartilage surface (R_c) had a significant coefficient of determination with R_q and A₁₂ (R_LMMm²=0.79); however, R_c did not correlate with A₁. Concerning the collagen characteristic in the superficial zone, R_c was found to be a sensitive indicator reflecting collagen disorganization, not collagen content, for the early degeneration samples.

In Vivo Evaluation of the Potential of High-Frequency Ultrasound for Arthroscopic Examination of the Shoulder Joint

OBJECTIVE

Accurate arthroscopic evaluation of cartilage lesions could significantly improve the outcome of repair surgery. In this study, we investigated for the first time the potential of intra-articular ultrasound as an arthroscopic tool for grading cartilage defects in the human shoulder joint in vivo and compared the outcome to results from arthroscopic evaluation and magnetic resonance imaging findings.

DESIGN

A total of 26 sites from 9 patients undergoing routine shoulder arthroscopy were quantitatively evaluated with a clinical intravascular (40MHz) ultrasound imaging system, using the regular arthroscopy portals. Reflection coefficient (R), integrated reflection coefficient (IRC), apparent integrated backscattering (AIB), and ultrasound roughness index (URI) were calculated, and high-resolution ultrasound images were obtained per site. Each site was visually graded according to the International Cartilage Repair Society (ICRS) system. "Ultrasound scores" corresponding to the ICRS system were determined from the ultrasound images. Magnetic resonance imaging was conducted and cartilage integrity at each site was classified into 5 grades (0 = normal, 4 = severely abnormal) by a radiologist.

RESULTS

R and IRC were lower at sites with damaged cartilage surface (P = 0.033 and P = 0.043, respectively) and correlated with arthroscopic ICRS grades (r s = -0.444, P = 0.023 and r s = -0.426, P = 0.03, respectively). Arthroscopic ICRS grades and ultrasound scores were significantly correlated (rs = 0.472, P = 0.015), but no significant correlation was found between magnetic resonance imaging data and other parameters.

CONCLUSION

The results suggest that ultrasound arthroscopy could facilitate quantitative clinical appraisal of articular cartilage integrity in the shoulder joint and provide information on cartilage lesion depth and severity for quantitative diagnostics in surgery.

The effect of cartilage degeneration on ultrasound speed in human articular cartilage

OBJECTIVES

We investigated the effect of cartilage degeneration on ultrasound speed in human articular cartilage in vitro.

METHODS

Ultrasound speed was calculated by the time-of-flight method for 22 femoral condyle osteochondral blocks obtained from osteoarthritis patients. In parallel, histological evaluation of specimens was performed using the modified Mankin and OARSI scores.

RESULTS

The mean ultrasound speed was 1757 ± 109 m/s. Ultrasound speed showed significant negative correlation with OARSI score, and a decreasing tendency with high Mankin scores. Good correlation was found between the optically measured and the calculated cartilage thickness.

CONCLUSION

Our results show that articular cartilage degeneration has relatively little influence on ultrasound speed. In addition, morphological evaluation of articular cartilage using a preset value of ultrasound speed seems to offer relatively accurate results.

Non-invasive and in vivo assessment of osteoarthritic articular cartilage: a review on MRI investigations

Early detection of knee osteoarthritis (OA) is of great interest to orthopaedic surgeons, rheumatologists, radiologists, and researchers because it would allow physicians to provide patients with treatments and advice to slow the onset or progression of the disease. Early detection can be achieved by identifying early changes in selected features of degenerative articular cartilage (AC) using non-invasive imaging modalities. Magnetic resonance imaging (MRI) is becoming the standard for assessment of OA. The aim of this paper was to review the influence of MRI on the selection, detection, and measurement of AC features associated with early OA. Our review of the literature indicates that the changes associated with early OA are in cartilage thickness, cartilage volume, cartilage water content, and proteoglycan content that can be accurately, consistently, and non-invasively measured using MRI. Choosing an MR pulse sequence that provides the capability to assess cartilage physiology and morphology in a single acquisition and advanced multi-nuclei MRI is desirable. The results of the review indicate that using an ultra-high magnetic strength, MR imager does not affect early OA detection. In conclusion, MRI is currently the most suitable modality for early detection of knee OA, and future research should focus on the quantitative evaluation of early OA features using advances in MR hardware, software, and data processing with sophisticated image/pattern recognition techniques.

Arthroscopic Ultrasound Assessment of Articular Cartilage in the Human Knee Joint: A Potential Diagnostic Method

OBJECTIVE

We tested whether an intra-articular ultrasound (IAUS) method could be used to evaluate cartilage status arthroscopically in human knee joints in vivo.

DESIGN

Seven patients undergoing arthroscopic surgery of the knee were enrolled in this study. An ultrasonic examination was conducted using the same portals as in the arthroscopic surgery. A high-frequency (40-MHz) ultrasound transducer (diameter = 1 mm) was directed to the desired location on the articular surface under arthroscopic control. In addition to ultrasound data, an IAUS video and optical video through the arthroscope were recorded. Classification of cartilage injuries according to International Cartilage Repair Society, as conducted by the orthopedic surgeon, provided reference data for comparison with the IAUS.

RESULTS

The IAUS method was successful in imaging different characteristics of the articular surfaces (e.g., intact surface, surface fibrillation, and lesions of varying depth). In some cases, also the subchondral bone and abnormal internal cartilage structure were visible in the IAUS images. Specifically, using the IAUS, a local cartilage lesion of 1 patient was found to be deeper than estimated arthroscopically.

CONCLUSIONS

The IAUS method provided a novel arthroscopic method for quantitative imaging of articular cartilage lesions. The IAUS provided quantitative information about the cartilage integrity and thickness, which are not available in conventional arthroscopy. The present equipment is already approved by the Food and Drug Administration for intravascular use and might be transferred to intra-articular use. The invasiveness of the IAUS method might restrict its wider clinical use but combined with arthroscopy, ultrasonic assessment may enlarge the diagnostic potential of arthroscopic surgery.

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.

Correlation of dynamic impact testing, histopathology and visual macroscopic assessment in human osteoarthritic cartilage

OBJECTIVE

Improved staging of cartilage degeneration is required, particularly during the early stages. We correlated mechanical properties with histological and macroscopic findings.

METHODS

One hundred and twenty cartilage samples were obtained during total knee arthroplasty. Two adjacent plugs were harvested--one for histological classification and one for macroscopic and biomechanical purposes. Dynamic impact testing was performed; normal stress, dissipated energy (∆E), tangent modulus and stiffness were evaluated.

RESULTS

Samples were classified according to six categories of the ICRS histological scale. Mechanical characteristics revealing significant differences between the groups (p < 0.01) were specific damping and related absolute ∆E. A significant correlation was found between the macroscopic score and specific damping, as well as absolute and relative ∆E (p < 0.01). A strong relation was revealed between relative ∆E and cartilage thickness (p < 0.001; R (2) = 0.69).

CONCLUSIONS

Only ∆E correlated with the condition of the cartilage--the value increased with decreasing quality-and is the most suitable characteristic. This change appears substantial in initial stages of cartilage deterioration.

Ultrasonographic evaluation of degenerative changes in the distal radioulnar joint: correlation of findings with gross anatomy and MR arthrography in cadavers

OBJECTIVE

To determine the accuracy of ultrasonography (US) in the evaluation of degenerative changes in the distal radioulnar joint (DRUJ).

METHODS AND MATERIALS

Ten cadaveric specimens were obtained. US evaluation of cartilage degeneration and thickness was performed by two independent and blinded readers (R1 and R2). Gross anatomy and MR arthrography evaluated by two readers in consensus served as the reference standard. The joint surface not accessible to US was measured.

RESULTS

US interreader agreement was non-existent for cartilage thickness measurements and moderate for cartilage degeneration grading (weighted kappa = 0.41). Comparing US and MR imaging evaluation, there was no correlation between US R1 and MR imaging (Pearson correlation coefficient [PCC] = 0.352) and a moderate correlation between US R2 and MR imaging (PCC = 0.570) concerning cartilage thickness measurements. Concerning cartilage degeneration grading, there was a moderate to strong (R1 Spearman correlation coefficient [SCC] = 0.729)/R2 SCC = 0.767) correlation concerning cartilage degeneration grading. Comparing US and gross anatomic evaluation, there was no correlation for US R1 (PCC = 0.220) and a strong correlation for US R2 (PCC = 0.922) concerning cartilage thickness measurements, and a strong to moderate correlation (R1 SCC = 0.808/R2 SCC = 0.597) concerning cartilage degeneration grading. The mean sector of the articular surface of the ulna head not accessible to US was 13°.

CONCLUSION

In conclusion the DRUJ is accessible to US except in the central 13° sector of the joint surface. US was approved to be sufficient in demonstrating advanced stages of cartilage degeneration. Thus, US of the DRUJ is recommended in patients suffering from ulnar-sided wrist pain.

More intrinsic parameters should be used in assessing degeneration of articular cartilage with quantitative ultrasound

During the last decade, the quantitative ultrasound technique has been widely employed as a versatile modality to investigate a thin but crucial tissue layer – the articular cartilage. Previous studies provide information about the morphology and mechanical and acoustic properties of the tissue derived from ultrasound measurements and correlate them with cartilage degeneration. In a previous issue of Arthritis Research & Therapy, Kuroki and colleagues presented a study about the relationship between International Cartilage Repair Society grading and ultrasound echo magnitude, duration, and interval in human knee cartilage. We think indirect measurements of the intrinsic physical characteristics of cartilage, as reported in this study, should be interpreted more carefully as they can be affected by many experimental and physical factors. In this editorial, we offer our opinion that more intrinsic material parameters should be selected for the assessment of degeneration states of cartilage using quantitative ultrasound.