Aim. The aim of our study was to assess macro– and microscopically the knee cartilaginous lesions outcome treated by mosaicplasty.

Material and method Our study included 32 patients which underwent mosaicplasty for nondegenerative cartilaginous lesions of the knee and a second look arthroscopy. In 21 patients, minibiopsies from the repaired lesion were performed under arthroscopic control (from the cartilaginous region of the transplanted osteocartilaginous grafts and from the spaces between grafts). All repaired lesions were carefully examined during arthroscopy and all harvested minifragments were studied by optical microscopy (staining method – hematoxylin eosin).

Results Macroscopically, the articular surface of the repaired cartilaginous lesions was smooth and congruent to the adjacent surfaces. The aspect and resistance to compression of grafted area was similar to those of the normal surrounding cartilage. The transferred cartilage maintained its height, being at the level of the neighboring cartilage. One year postoperatively, the limits of the cartilaginous autografts were still visible. Two years postoperatively, these limits were no longer visible. Microscopically, the region of the former lesion was constituted mainly by viable hyaline cartilage. Fibrous cartilaginous tissue was visualized in the spaces between the grafts.

Conclusions The second look arthroscopy showed that after mosaicplasty the repaired articular surface was smooth, leveled, homogenous and congruent to adjacent cartilage. The spaces between grafts are progressively covered by fibrous cartilaginous tissue with a more textured and uneven surface. Mosaicplasty is a biological surgical technique which restores the normal osteocartilaginous architecture of the most part of the grafted area. The transplanted osteocartilaginous cylindrical grafts maintain its viability and mechanical properties.