[Evaluation of cartilage degeneration by near infrared spectroscopy (NIRS): methodical description and systematic literature review].

Damage to hyaline cartilage is the most important pathophysiological tool in the development of osteoarthritis. Cartilage lesions are the most frequent pathological findings during arthroscopic operations. Arthroscopies as well as magnetic resonance tomography are gold standards for detection of cartilage lesions. But the arthroscopic evaluation of cartilage lesions is descriptive and subjective only. The surgeon is able to differentiate between intact cartilage surface, softening, superficial or deep fissure or flake and finally a complete defect. In routine arthroscopy the grading mostly is made by use of different scores [e.g. ICRS (International Cartilage Repair Society), Outerbridge, Insall, Jäger-Wirth or others]. Because the arthroscopic evaluation is subjective the reliability of this method is poor. Spectroscopic methods are established for evaluation of different tissue diseases in different indications. NIRS (near infrared spectroscopy) has become an important method for medical diagnostics in the last years. NIR is very energy-rich and suitable for glass fibre transport without relevant reduction. Insofar this technology may be ideal for endoscopic procedures. Our systematic literature review reveals that NIRS is a sufficient method for an objective diagnosis of cartilage lesions. In the current work we demonstrate an NIRS-based device for intraoperative, real-time cartilage evaluation. Furthermore, we discuss the possible clinical consequences from such measurements.