Pathomorphology of articular cartilage of the knee and ankle joints in experimental repair of postresection tibial defect using the Ilizarov method and cement spacer

Abstract

Objective To explore histomorphological characteristics of articular cartilage of the knee and ankle joints in repair of postresection tibial defects using the Ilizarov method and cement spacer. Material and methods A defect-nonunion was simulated in the proximal tibia of 10 mongrel dogs using the Ilizarov external fixation followed by application of cement spacer to repair a defect-diastasis of at least 15 % of the original bone length. The spacer was removed after 30 days and tibial distraction commenced at a rate of 1 mm four times at the site of transverse osteotomy in the distal tibia for bone docking. Histomorphological evaluation of articular cartilage of the trochlea of the talus and femoral condyles was produced at 60-day fixation (F60) and 30 days following frame removal (FR30). Results The structure of articular cartilage of the trochlea of the talus was intact at F60 and FR30, and morphometric parameters were comparable with those in controls at the end of experiment. Pannus was detected on the articular surface of the femoral condyles in 60 % of observations, and subchondral bone structure appeared to be impaired with marrow pannus penetrating deep into the cartilage. Intact zonal structure of the cartilage with no pannus, persisted integrity of the basophilic line, thin subchondral bone were observed in 40 % of observations. Compared to controls, greater number of empty lacunes and cartilage thinning were recorded at FR30. Conclusion The Ilizarov external fixation and cement spacer used to repair simulated postresection tibial defect was shown to be a cartilage-sparing procedure for the ankle joint with a higher risk of irreversible destructive changes in articular cartilage of the knee joint.

Keywords

• tibia defect
• masquelet technique
• articular cartilage
• histomorphometry