Comparative Study between Radiological Classification and Macro and Microscopic Analysis on Osteoarthritis Lesions of the Knee.

OBJECTIVES To compare the modified Ahlbäck radiological classification with macroscopic analysis of knee injuries and locate a chondral lesion in the tibial plateau, and to correlate this with integrity or lack of integrity of the anterior cruciate ligament. MATERIAL AND METHODS Between July and December 2009, 40 patients of mean age 67.1 years with an indication for total knee arthroplasty were selected. The modified Ahlbäck radiological classification was used. The International Cartilage Repair Society classification was used for macroscopic analysis of the lesions. Chondral injuries were correlated with the integrity or lack of integrity of the anterior cruciate ligament. RESULTS Regarding the radiological classification of the knees, three (7.5%) were classified as grade 1, two (5%) as grade 2, 17 (42.5%) as grade 3, 16 (40%) as grade 4 and two (5%) as grade 5. The macroscopic analysis of the knee showed that 25 patients (62.5%) had very severe injury and 15 (37.5%), severe. In eight knees (20%) with ruptured ACL, the lesion extended to the posterior region of the medial tibial plateau. When the ACL was intact, the lesion was located in the anterior-central region. CONCLUSION Knee osteoarthritis of grades 4 and 5 in the radiological classification, showed agreement with the macroscopic analysis, i.e. very severe chondral injury. However, grades 1, 2 and 3 were discordant. In the cases of osteoarthritis with intact ACL, the lesion was located in the anterior-central region of the medial tibial plateau, and those with ruptured ACL had the lesion extending to the posterior region of the plateau.