Takashi Habata

Measurement of the Mechanical Condition of Articular Cartilage with an Ultrasonic Probe : Quantitative Evaluation Using Wavelet Transformation

OBJECTIVE To develop a new diagnostic technology to evaluate articular cartilage quantitatively by introducing an ultrasonic probe into the knee joint under arthroscopy and analyzing the A-mode echogram by means of wavelet transformation. DESIGN Quantitative evaluation using comparison of two indices on the wavelet map and macroscopic evaluation using the Outerbridge classification. As the quantitative indices on the wavelet map, the maximum magnitude and the echo duration which was defined as the length of time that included 95% of echo signal were selected. BACKGROUND Quantitative evaluation of articular cartilage in situ is required for new tissue-engineered cartilage but an evaluation system that fully meets this requirement has yet to be established for clinical use. METHODS Human articular cartilage specimens were analyzed using an ultrasonic probe after macroscopic evaluation and the cartilage characteristics on the echo duration-maximum magnitude graph were examined. RESULTS There were significant differences between grade 1 and 3, and grade 2 and 3 in the echo duration and maximum magnitude. The cartilage specimens had a L-shaped distribution in echo duration-maximum magnitude graph. CONCLUSIONS The present study is the new quantitative evaluation system of the articular cartilage in situ and a clinical trial under arthroscopy is presently underway. The ultrasonic measurement is highly reproducible, so we can expect this system to be suitable for in situ reliable examination under arthroscopy. RELEVANCE Precise evaluation of articular cartilage is of particular importance for longitudinal clinical trials for determination of best surgical option or effect of new chondroprotective drugs in arthritic disease and rheumatoid arthritis.

Arthroscopic meniscal repair using fibrin glue. Part I: Experimental study

An experimental study of rabbit menisci was carried out to evaluate the healing-promoting properties of fibrin glue and fibrin glue-containing marrow cells. A full-thickness defect, 1.5 mm in diameter, was made within the avascular portion of the meniscus and left empty in 20 menisci (C group), filled with fibrin glue in 20 menisci (F group), and filled with fibrin glue-containing marrow cells in 20 menisci (M group). Measurements of the remaining defects and histological examinations were performed 1, 3, 6, and 12 weeks after each procedure. Overall, the remaining defects in the F group and, particularly, in the M group were significantly smaller than those in the C group at the various time points. Furthermore, the results of histological study showed earlier mature healing of the defects in the M group than of those in the F group. Our results suggest that fibrin glue, especially in a preparation containing marrow cells, may enhance meniscal healing.

Arthroscopic meniscal repair using fibrin glue. Part II: Clinical applications

Since 1984 we have arthroscopically repaired meniscal tears using a purified fibrin glue. This article describes clinical application of a fibrin-based glue to arthroscopic meniscal repair and a long-term follow-up study of 61 repaired menisci in 40 patients (average follow-up, 8 years; range, 5.1 to 11.4 years). Of these patients, 6 complained of recurrent meniscal symptoms and received partial meniscectomy. According to stepwise logistic regression analysis, the factors most strongly correlated with recurrent symptoms were insufficiency of the associated anterior cruciate ligament, repairs of fresh tears, and repairs requiring supplementary meniscal sutures (P < .05).

Quantitative ultrasound can assess the regeneration process of tissue-engineered cartilage using a complex between adherent bone marrow cells and a three-dimensional scaffold

Articular cartilage (hyaline cartilage) defects resulting from traumatic injury or degenerative joint disease do not repair themselves spontaneously. Therefore, such defects may require novel regenerative strategies to restore biologically and biomechanically functional tissue. Recently, tissue engineering using a complex of cells and scaffold has emerged as a new approach for repairing cartilage defects and restoring cartilage function. With the advent of this new technology, accurate methods for evaluating articular cartilage have become important. In particular, in vivo evaluation is essential for determining the best treatment. However, without a biopsy, which causes damage, articular cartilage cannot be accurately evaluated in a clinical context. We have developed a novel system for evaluating articular cartilage, in which the acoustic properties of the cartilage are measured by introducing an ultrasonic probe during arthroscopy of the knee joint. The purpose of the current study was to determine the efficacy of this ultrasound system for evaluating tissue-engineered cartilage in an experimental model involving implantation of a cell/scaffold complex into rabbit knee joint defects. Ultrasonic echoes from the articular cartilage were converted into a wavelet map by wavelet transformation. On the wavelet map, the percentage maximum magnitude (the maximum magnitude of the measurement area of the operated knee divided by that of the intact cartilage of the opposite, nonoperated knee; %MM) was used as a quantitative index of cartilage regeneration. Using this index, the tissue-engineered cartilage was examined to elucidate the relations between ultrasonic analysis and biochemical and histological analyses. The %MM increased over the time course of the implant and all the hyaline-like cartilage samples from the histological findings had a high %MM. Correlations were observed between the %MM and the semiquantitative histologic grading scale scores from the histological findings. In the biochemical findings, the chondroitin sulfate content increased over the time course of the implant, whereas the hydroxyproline content remained constant. The chondroitin sulfate content showed a similarity to the results of the %MM values. Ultrasonic measurements were found to predict the regeneration process of the tissue-engineered cartilage as a minimally invasive method. Therefore, ultrasonic evaluation using a wavelet map can support the evaluation of tissue-engineered cartilage using cell/scaffold complexes.

Marrow cell culture on poly-L-lactic acid fabrics

Bone marrow cells from rat femurs were cultured in Eagle Minimum Essential Medium containing 15% fetal calf serum until confluence. After the cells were trypsinized, they were subcultured on fabrics made of biodegradable poly-L-lactic acid for 2 weeks in the medium containing fetal calf serum, ascorbic acid phosphate, beta-glycerophosphate, and with and without dexamethasone. In the presence of dexamethasone, the fabrics showed many mineralized nodules together with cuboidal shaped cells that had osteoblastic activity, as evidenced by high alkaline phosphatase activity and the appearance of osteocalcin messenger ribonucleic acid. However, in the absence of dexamethasone, nodules did not form and many fibroblastic cells appeared with no evidence of osteoblastic activity. These results indicate the possibility of making a hybrid ligament substitute having an in vitro prefabricated bone anchor.

Relationship Between Meniscal Degeneration and Element Contents

The purpose of this study is to investigate the relationship between meniscal degeneration and element contents. The contents of elements (calcium, phosphorus, sulfur, and magnesium) in the menisci from 17 patients with osteoarthritis (OA) of the knee, 6 with rheumatoid arthritis (RA), and 2 who underwent the surgical operation for malignant tumors (control) were analyzed by inductively coupled plasma-atomic emission spectrometry, and the menisci were divided into four stages (Stage 0–3) of histological degeneration.The calcium contents of the menisci were 0.26±0.16 in Stage 0, 0.50±0.37 in Stage 1, and 0.69±0.66 in Stage 2, respectively (the values represent mg elements/g dry tissue). They increased with the progression of the stage. This tendency was found in the menisci with OA, but was not clear in those with RA. The calcium content in the control group was 0.17±0.09 mg/g. There was no significant relationship between the stage of degeneration and the contents of phosphorus, sulfur, or magnesium. The calcium content of the meniscus might indicate the degree of meniscal degeneration.

Quantitative Ultrasound Can Assess Living Human Cartilage

Introduction rticular cartilage forms the bearing surface of synovial joints. It provides a nearly friction-free load-bearing joint surface so that humans can make smooth movements without pain. However, this tissue may be damaged by trauma or inflammatory disease processes and may undergo progressive degeneration resulting in osteoarthritis. Once articular cartilage is damaged, the cartilage is not restored to its normal state because of its limited capacity for repair. New therapies such as mosaicplasty and cultured chondrocyte transplantation are used clinically for the treatment of cartilage defects. Moreover, numerous tissue-engineering initiatives have been undertaken to treat cartilage defects. Each treatment has its own strong and weak points, and it remains difficult to choose among them. Therefore, in vivo evaluation is essential to determine the best treatment, but the accurate assessment of articular cartilage in a clinical context has not yet been established. We developed a new ultrasonic evaluation system in which the acoustic properties of articular cartilage were measured by introducing an ultrasonic probe into the human joint arthroscopically. The analysis system is based on waveA

Spectrocolorimetric assessment of cartilage plugs after autologous osteochondral grafting: correlations between color indices and histological findings in a rabbit model

We investigated the use of a commercial spectrocolorimeter and the application of two color models (L* a* b* colorimetric system and spectral reflectance distribution) to describe and quantify cartilage plugs in a rabbit model of osteochondral autografting. Osteochondral plugs were removed and then replaced in their original positions in Japanese white rabbits. The rabbits were sacrificed at 4 or 12 weeks after the operation and cartilage samples were assessed using a spectrocolorimeter. The samples were retrospectively divided into two groups on the basis of the histological findings (group H: hyaline cartilage, successful; group F: fibrous tissue or fibrocartilage, failure) and investigated for possible significant differences in the spectrocolorimetric analyses between the two groups. Moreover, the relationships between the spectrocolorimetric indices and the Mankin histological score were examined. In the L* a* b* colorimetric system, the L* values were significantly lower in group H than in group F (P = 0.02), whereas the a* values were significantly higher in group H than in group F (P = 0.006). Regarding the spectral reflectance distribution, the spectral reflectance percentage 470 (SRP470) values, as a coincidence index for the spectral reflectance distribution (400 to 470 nm in wavelength) of the cartilage plugs with respect to intact cartilage, were 99.8 ± 6.7% in group H and 119.8 ± 10.6% in group F, and the difference between these values was significant (P = 0.005). Furthermore, the a* values were significantly correlated with the histological score (P = 0.004, r = -0.76). The SRP470 values were also significantly correlated with the histological score (P = 0.01, r = 0.67). Our findings demonstrate the ability of spectrocolorimetric measurements to predict the histological findings of cartilage plugs after autologous osteochondral grafting. In particular, the a* values and SRP470 values can be used to judge the surface condition of an osteochondral plug on the basis of objective data. Therefore, spectrocolorimetry may contribute to orthopedics, rheumatology and related research in arthritis, and arthroscopic use of this method may potentially be preferable for in vivo assessment.

How to diagnose isolated articular cartilage lesions of the knee in a consulting room

In order to clinically diagnose articular cartilage lesions of the knee in a medical examination, 121 knees (117 cases) with isolated lesions were investigated. Lesions of the patella (PAT), facies patellaris (F-PAT), lateral femoral condyle (LFC), lateral tibial plateau (LTP), medial femoral condyle (MFC), and medial tibial plateau (MTP) were found in 15, 10, 9, 57, 24, and 6 knees, respectively. The lesions often occurred in athletes, but many cases with lesions did not have a history of trauma. Giving way, pain in maximal flexion, pain after exercise, and pseudolocking were relatively common symptoms. Atrophy of the thigh on the involved side was not severe. Mild limitations in both extension and flexion were often found. Hydrarthrosis was frequent in cases with F-PAT, LFC, and MFC lesions. Valgus alignment was found in LTP lesions, while varus alignment was found in MFC and MTP lesions. Findings of fibrillation in PAT, flaps, deep defects, and softening in F-PAT and MFC, deep defects in LFC, and softening and fissuring in LTP were often seen during arthroscopy. Cartilage lesions such as softening were also thought to be related to the symptoms. Increases in joint fluid may suggest lesions in F-PAT, LFC or MFC where deep and wide lesions often occur. Cases with valgus alignment may have LTP lesions and those with varus alignment may have MFC or MTP lesions.