Structural reorganization of the cartilage tissue in chronic osteomyelitis of the foot bones

Abstract

Purpose To study structural reorganization of the cartilage tissue of the joints, depending on the location of osteomyelitis in the bones of the foot. Materials and methods Intraoperative material of 16 patients with chronic osteomyelitis in the foot bones was studied (10 males in the average age 45.3 (33 ÷ 56) years and six females in the average age of 40 (23 ÷ 53) years). The material was resected fragments of the osteo-cartilaginous complex: calcaneus, talus and adjacent joint tissue (subtalar and talo-navicular, phalangeal and metatarsal bones and metatarsophalangeal joint). The material was fixed in 10 % formalin. Paraffin sections (5-7 μm thick) were stained with hematoxylin and eosin. Histological studies were performed using a stereo microscope "AxioScope.A1" with a digital camera "AxioCam" and software "Zenblue" (CarlZeiss MicroImaging GmbH, Germany). Results The subchondral bone plate and basophilic line remained continuous and the vessels did not penetrate into the cartilaginous tissue in chronic osteomyelitis of the calcaneus and talus, when the osteomyelitis foci were remote from the articular surface. If an osteomyelitic lesion was present in the subchondral zone, abnormalities in the articular cartilage were detected both from the side of the subchondral bone and on the articular surface; and vascular invasion was observed. In the deep zone of the cartilage, there were hypertrophic chondrocytes with signs of chondroptosis, what indicated a violation of the chondrohematic barrier. Disorders of the basophilic line and penetration of the bone marrow pannus were revealed. From the side of the articular surface, a synovial pannus was observed invading the cartilage matrix. In chronic osteomyelitis of the phalanges and metatarsal bones, regardless of the phase of the inflammatory process, in all observations, disorders in the structure of the subchondral bone plate and articular cartilage were detected; there was invasion of blood vessels from the subchondral zone and articular surface that might be explained by the small size of those bones. Conclusion The intensity of articular cartilage destruction in chronic osteomyelitis of the calcaneus and talus depended on the location of the osteomyelitis focus and the phase of the inflammatory process. In chronic osteomyelitis of the phalanges and metatarsal bones, regardless of the phase of the inflammatory process, there were disorders in the structure of the articular cartilage and vascular invasion. The findings on structural changes in the articular cartilage in chronic osteomyelitis of adjacent bones are helpful for defining the tactics of surgical treatment.