Traumatic and degenerative cartilage lesions: arthroscopic differentiation using near-infrared spectroscopy (NIRS)

Abstract

Cartilage lesions or defects are the most common finding during knee arthroscopy. During arthroscopy, it is often difficult to differentiate between degenerative and traumatic cartilage lesions. The study aimed to determine the impact of near-infrared spectroscopy (NIRS) on the distinction between traumatic and degenerative cartilage lesions in the medial femoral condyle (MFC). It was hypothesized that NIRS as able to distinguish between traumatic and degenerative cartilage lesions. Arthroscopic evaluation was performed in six patients who had undergone anterior cruciate ligament (ACL) reconstruction and in six patients who had undergone high tibial osteotomy (HTO). In both groups, a grade III cartilage lesion was present within the MFC. NIRS evaluation was performed with a special probe (arthrospec-one, Arthrospec GmbH, Jena, Germany). NIRS measurements produced semi-quantitative values ranging from 0 (heavily degenerated cartilage) to 100 (completely intact cartilage). The mean near-infrared-light absorption within the traumatic lesions in the MFC of the ACL group was 71.5 (range 61-80). In the HTO patients, this value was significantly (p < 0.001) lower at 31.7 (range 31-33). The margin of the MFC outside the lesion in the ACL group had the same adsorption as the lesion (p = 0.549). After an injury, cartilage has a normal or nearly normal absorbance on near-infrared-light. Thus, it is possible to distinguish intraoperatively between traumatic and degenerative lesions. In addition, our results demonstrate that evaluating cartilage with NIRS is a dependable method for improving the diagnosis of significant chondral lesions.