Viability of chondroscopy as a means of cartilage assessment

Correlation between arthroscopic and histopathological grading systems of articular cartilage lesions in knee osteoarthritis

PURPOSE

Arthroscopic and particularly histopathological assessments have been used to evaluate alterations of knee cartilage in osteoarthritis (OA). The aim of this study was to examine the correlation between an arthroscopic method to grade the severity of chondropathies and the histological/histochemical grading system (HHGS) applied to the corresponding articular cartilage areas in knee OA.

METHODS

The articular cartilage surface was examined by chondroscopy using the Beguin and Locker severity criteria, analysing the lesions in 72 chondroscopic areas. Afterwards, samples were obtained by dividing the cartilage surface of the medial tibiofemoral compartment of three OA knee joints into equal squares and they were evaluated histologically using the HHGS. The correlation between both grading methods was assessed using the weighted Kappa coefficient (K(w)).

RESULTS

The results obtained with both scores showed good agreement (K(w): mean+/-standard deviation, 0.619+/-0.071). While the average HHGS scores of the chondral samples showed a better agreement with arthroscopic grades 0, I and II, the arthroscopic evaluation has a tendency to overestimate chondral lesions for histological grades III and IV. The intra- and inter-observer reliability of the HHGS evaluation of chondral lesions was excellent (Intraclass Correlation Coefficient: 0.909 and 0.941, respectively).

CONCLUSION

In this study, we found a good quantitative correlation between established arthroscopic severity and histopathological scoring systems, particularly in less advanced lesions. Our results suggest that the arthroscopic method is a valuable tool in clinical research to score chondropathies in the medial femorotibial compartment of the OA knee, although some limitations should not be overlooked.

Arthroscopy as a research tool: a review

Arthroscopy continues to experience a growth in interest from the rheumatology community reflecting a common desire to gain better understanding of the underlying processes in inflammatory and degenerative joint diseases. Arthroscopy provides the ability to assess the internal appearances of a joint in a well tolerated and repeatable manner, to obtain tissue samples from the principle site of pathology within the joint and thus confers on it the role of "gold standard" amongst currently available imaging techniques. The evolution of arthroscopy is reviewed together with an overview of the evidence obtained from its research application in the rheumatology. Methodology for the conduct of arthroscopy and synovial biopsy is described.

Clinical assessment and significance of inflammation in knee osteoarthritis

The recognition of the role of cytokines in osteoarthritis (OA) has suggested new approaches for therapy of the disease, and also increases the importance of clinical assessment of inflammation. Accurate identification of the presence and degree of inflammation might allow the clinician to predict which individuals would respond to therapy with anti-inflammatory drugs. Several laboratory and clinical markers have been evaluated which may also serve as predictors and indicators of response to therapy and overall outcome.

Assessment of articular cartilage and subchondral bone: subtle and progressive changes in experimental osteoarthritis using 50 MHz echography in vitro

The main objectives of this work were to demonstrate the potential of 50 MHz echography for assessing initial and progressive morphological and structural changes of articular cartilage and bone developed in an experimental model of osteoarthritis (OA). Degenerative lesions were induced in rat knees by the unilateral intra-articular injection of a 3 mg dose of mono-iodo-acetic acid. To assess the lesion progression, the animals (n = 30) were sacrificed at different time intervals up to 8 weeks after the injection. Three-dimensional echographic data were acquired in vitro on patellar cartilage and bone at various stages of the remodeling process using a scanning ultrasound microscope. Changes involving the OA cartilage characteristics are discussed relative to those of the contralateral control joint which received a placebo. Images of control cartilage showed a smooth hyperechoic articular surface and an echoic matrix. The cartilage thickness was 266 +/- 44 microns (mean +/- SD) in the central region of the tissue. The precision of ultrasonic thickness measurements was better than 1.3%. First changes in cartilage internal structure and subchondral bone appeared on ultrasound images 3 days after the injection and were even more evident by day 7. They resulted in a slight thinning of the cartilage, a 30% increase of its internal structure echogenicity, and the appearance of echoic zones in subchondral bone. Histologic findings confirmed chondrocyte depletion and degeneration, decrease of matrix proteoglycans, and fibrovascular connective tissue proliferation at the subchondral plate. Progressive and severe lesions at both bone and cartilage surface and internal structure were assessed and correlated to histologic features. These results show that high resolution echography is sensitive to subtle and progressive osteochondral remodeling. This technique has the potential to be used for intra-articular quantitative imaging and assessment of early changes in bone and cartilage structure associated with natural human disease.

Diagnosis of osteoarthritis. Guidelines and current pitfalls

Diagnostic and classification guidelines for osteoarthritis based on clinical and radiographic signs for the most frequently involved joints (knee, hip and hand) have been developed by the American College of Rheumatology. Excellent, new 'high tech' biochemical and imaging methods and guidelines for clinical evaluation of the condition and its therapy have recently been developed and validated. Accordingly, we have consistent and reliable methods for assessing the established condition, but they provide little help in making an early and correct diagnosis for the different forms of osteoarthritis. Both the diagnostic process and the differential diagnosis consist of careful history taking and detailed analysis of the complaints (especially pain), with proper physical examination including a search for the source of pain and tenderness. Not all deformities and pain in and around the joints are signs and symptoms of osteoarthritis, even if the patient is of 'osteoarthritis age' and the joint shows 'osteoarthritis signs' on the x-ray. On the other hand, even if the underlying disease is osteoarthritis, the symptoms and signs may be due to disorders secondary to the basic disease (e.g. enthesopathy or tendinopathy) and the patient's complaints can be helped more easily by physiotherapy and local injections. The course of the disease and close follow-up yield diagnostic clues in cases where the cross-sectional diagnostic measures fail to provide them. Analysis of serum, joint fluid and x-ray films can be of diagnostic value, and other imaging methods (ultrasound, radioisotope scanning, computerised tomography, magnetic resonance imaging, arthroscopy) are also useful tools. Differential diagnosis is not only of theoretical value; misdiagnosis of osteoarthritis leads to either omitted or unnecessary treatment, and causes psychological stress to the patient.