Mapping of donor and recipient site properties for osteochondral graft reconstruction of subchondral cystic lesions in the equine stifle joint.

This study focuses on improving the process of osteochondral graft reconstruction in the stifle joint of horses by matching the properties of the donor and recipient sites. The research shows that there is considerable variation in the properties across the stifle joint, but identifies possible areas that can act as suitable donor sites for reconstruction.

Research Objectives

• To get a comprehensive understanding of the biomechanical and biochemical parameters influencing the healing and function of osteochondral grafts used to reconstruct subchondral cystic lesions in the stifle joint of horses.
• To identify suitable donor sites within the joint for reconstructing the femoral condyles.

Methods

• Two sets of studies were conducted, with each involving the harvest of osteochondral cores (cartilage and bone tissue) from distal femurs (the lower part of the thigh bone).
• The first study engaged in determining the modulus of elasticity (measures a material’s resistance to being deformed) and ultimate stress of the subchondral bone. 56 osteochondral cores were harvested for this purpose from 6 distal femurs.
• The second study, involving 28 harvested cores from 6 distal femurs, measured cartilage aggregate modulus (a measure of the cartilage’s mechanical properties), thickness, and sulphated glycosaminoglycan (sGAG) content (sGAGs play an essential role in the cartilage’s resilience and load-bearing properties).
• Both studies also used micro-CT imaging to measure the subchondral bone mineral density and bone volume fraction.
• Data obtained were used to generate a visual comparison of joint surface characteristics.

Results

• The study found that the material properties of bone and cartilage significantly vary over the surface of the stifle joint.
• The central region of the medial condyle (a part often affected by subchondral cystic lesions) typically showed the highest bone strength and modulus values.
• The thickness and aggregate modulus of cartilage were determined to be highest in the medial femoral condyle and axial aspect of the lateral condyle.

Conclusions

• The trochlear groove and axial aspect of the lateral trochlear ridge were identified as the best-matching graft donors for reconstructing the medial condyle.
• The properties of the lateral condyle were found to be most comparable to those of the trochlear groove and axial aspect of the medial trochlear ridge.