ObjectiveThe aim of this study was to investigate whether human articular cartilage can be quantitatively evaluated using a spectrocolorimeter.Materials and methodsHuman articular cartilage specimens were analyzed using a spectrocolorimeter after macroscopic evaluation using the Outerbridge classification. The cartilage characteristics were examined, the L*, a*, b* colorimetric system, the spectral reflectance distribution and the yellow/red spectral reflectance percentage (Y/R SRP). Moreover, the results of the spectrocolorimetric evaluation were compared with the histological score described by Mankin et al.ResultsThere were significant differences among the macroscopic four grades in the L*, a* and Y/R SRP values. The spectral reflectance distribution of grade 1 cartilage exhibited a gradual increase in the spectral reflectance ratio as the wavelength increased. The spectral reflectance curves of grades 2 to 4 cartilage had dips at a wavelength of around 580 nm. Across all the measured wavelengths, there were lower reflectance ratios with the progression of cartilage degeneration. Moreover, correlations were observed between the spectrocolorimetric values and Mankin score. A strong relationship existed between Mankin score and he Y/R SRP values.ConclusionsThe present study is the first to clearly demonstrate the relationship between spectrocolorimetric evaluation and the degeneration of human articular cartilage. The spectrocolorimeter may be a new quantitative evaluation tool for articular cartilage with clinical potential.

This study aimed to show the results of osteochondritis dissecans fragment excision. We reviewed 85 patients (98 knees) with osteochondritis dissecans in a retrospective study of the results of merely excising the osteochondral lesion. Thirty-one knees were treated by only the removal of the fragment. Of these, it was possible to contact and examine 14 patients (14 knees); the average follow-up periods were 8.3 years (range 4.5-32 years). Knee function was evaluated according to the criteria of the International Knee Documentation Committee (IKDC), 12 knees in the 14 patients had no further symptoms and the 2 others had mild pain when going up- and downstairs. Roentgenograms at follow-up showed slight osteoarthritic changes. The preoperative femoro-tibial angle measured at surgery showed no marked change compared with that at follow-up. The study suggests that clinical and radiological results are good following removal of the osteochondral loose fragments are excised.

Although numerous methods for regenerating articular cartilage have been investigated, the regenerated tissue showed various histological findings from hyaline-like cartilage to fibrous tissue. Without biopsy, we are unable to know whether the cartilage regeneration method was histologically successful or not. We developed a new ultrasonic evaluation system for articular cartilage using the maximum magnitude (MM) from ultrasonic analysis. The purpose of this study was to investigate the usefulness of ultrasonic judgment of the cartilage regeneration procedure. Using our system we quantitatively evaluated tissue-engineered cartilage in rabbit cartilage defects. The specimens were retrospectively divided into two groups on the basis of histological findings and investigated whether significant differences in ultrasonic analysis could be found between the two (group H: hyaline-like cartilage group, successful; group F: fibrous tissue group, failure). In the ultrasonic findings, the MM was 1.11 +/- 0.32 in group H and 0.65 +/- 0.18 in group F and these differences were significant (P = 0.00061). Our results suggest that the ultrasonic evaluation system used in the present study is capable of judging the success or failure of cartilage regeneration procedures, and therefore, it could be a valuable tool arthroscopic diagnosis of cartilage regeneration. (c) 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.

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.

Cartilage engineered from mesenchymal stem cells (MSCs) requires a scaffold to keep the cells in the cartilage defect and to act as a support for inducing hyaline cartilage formation. We developed a novel three-dimensional special poly-lactic-glycolic acid (PLGA) scaffold that provided structural support and stimulated repair. Three-dimensional PLGA scaffolds seeded with cultured MSCs were transplanted into large defects in rabbit knees and analyzed histologically at 4 and 12 weeks after the operation. Our findings showed that in the engineered cartilage with the PLGA scaffold, the defects were filled with smooth, shiny white tissue macroscopically and hyaline-like cartilage histologically at 12 weeks after the transplantation. The structure of the novel PLGA scaffolds provided architectural support for the differentiation of progenitor cells and demonstrated successful induction of in vivo chondrogenesis.

Objective. To investigate ultrasonic evaluation methods for detecting whether the repair tissue is hyaline cartilage or fibrocartilage in new cartilage regeneration therapy.Methods. We examined four experimental rabbit models: a spontaneous repair model (group S), a large cartilage defect model (group L), a periosteal graft model (group P) and a tissue-engineered cartilage regeneration model (group T). From the resulting ultrasonic evaluation, we used %MM (the maximum magnitude of the measurement area divided by that of the intact cartilage) as a quantitative index of cartilage regeneration. The results of the ultrasonic evaluation were compared with the histological findings and histological score.Results. The %MM values were 61.1 +/- 16.5% in group S, 29.8 +/- 15.1% in group L, 36.3 +/- 18.3% in group P and 76.5 +/- 18.7% in group T. The results showed a strong similarity to the histological scoring.Conclusion. The ultrasonic examination showed that all the hyaline-like cartilage in groups S and T had a high %MM (more than 60%). Therefore, we could define the borderline between the two types of regenerated cartilage by the %MM.

OBJECTIVE:To evaluate regenerated articular cartilage quantitatively by introducing an ultrasonic probe into the knee joint under arthroscopy and analysing the A-mode echogram by means of wavelet transformation.METHODS:Three experimental rabbit models (spontaneous repair model, large cartilage defect model, treatment model) were examined using our ultrasonic evaluation system and a histological grading scale. From resulting wavelet map, the percentage of maximum magnitude was selected as the quantitative index of the ultrasonic evaluation system.RESULTS:The percentage maximum magnitude in the spontaneous repair model was 61.1%, that in the large defect model was 29.8% and that in the treatment model was 36.3%. There was modest correlation between the percentage maximum magnitude and the histological grading scale (r = -0.594)CONCLUSION:Our findings indicate that ultrasound analysis can predict the microstructure of regenerated cartilage.

INTRODUCTION:A lower threshold of suspicion is necessary for the appropriate diagnosis of a posterior horn tear in the medial meniscus. In these cases, radial tears or meniscus detachment from its insertion follow minor trauma and precipitate severe knee pain in middle-aged and elderly patients. The purpose of this paper is to demonstrate the key points for diagnosis through examination of the clinical features of this tear.MATERIALS AND METHODS:Arthroscopic examination of 250 knees with medial meniscus tears (and no ligamentous injuries; over 40 years old) identified 26 knees (26 tears) with a posterior horn tear. Of these 26 tears, 16 were radial, and 10 were detached.RESULTS:Eighty-five percent of patients could recall discrete events that preceded the pain. They described these events as a click or a feeling of shock. Afterwards, most patients complained of severe pain or giving way. Hydrarthrosis involving more than 5 ml was present in 81%. Most radiographs (92%) appeared nearly normal.CONCLUSION:It is important to note that this type of tear of the posterior horn in the medial meniscus is not rare. Because this area is difficult to visualize arthroscopically, it may be overlooked unless the threshold of suspicion is lowered.

OBJECTIVE:To investigate whether living human articular cartilage can be evaluated quantitatively by means of a new diagnostic technique that introduces an ultrasonic probe into the knee joint under arthroscopy and then analyzes the A-mode echogram by means of wavelet transformation.DESIGN:Intact and injured sites of living human articular cartilage were evaluated under arthroscopy. The maximum magnitude and the echo duration (defined as the length of time that included 95% of echo signal) were selected as the quantitative indices on the wavelet map.BACKGROUND:Quantitative evaluation of articular cartilage in situ has the potential to contribute to our understanding of cartilage breakdown and to the effectiveness of cartilage regeneration. However, a reliable method of quantitative cartilage evaluation has yet to be developed for clinical use.METHODS:Living human articular cartilage was analyzed using an ultrasonic probe under arthroscopy and the cartilage characteristics on the echo duration-maximum magnitude graph were examined.RESULTS:Unlike the L-shape distribution of human cadaver cartilage data, the distribution of the living human articular cartilage data showed a smooth curve with a steep initial gradient that flattens gradually at the highest value of echo duration on the echo duration-maximum magnitude graph.CONCLUSIONS:The present study suggests a new quantitative evaluation system for articular cartilage with clinical potential.