Biochemical, biomechanical and histological properties of osteoarthritic porcine knee cartilage: implications for osteochondral transplantation

Abstract

Cartilage lesions of the knee joint are frequently observed during arthroscopy and when surgical intervention is required, osteochondral autograft procedures are an established method of treatment. Frequently lesions are located on the medial femoral condyle (MFC), and typical donor locations for osteochondral grafts include the medial and lateral patellar groove. This technique provides good results, even when the quality of cartilage transplanted from an osteoarthritic joint is doubtful. This study characterizes biological, biomechanical and histological properties of cartilage explants from the patellar groove harvested from osteoarthritic joints. Cylindrical cartilage explants were harvested from the arthritic areas of the MFC as well as normal appearing regions of the medial and lateral patellar groove from porcine joints revealing various grades of osteoarthritis. Matrix synthesis rates were determined, and explants were investigated by mechanical testing and histology. Articular cartilage obtained from the typical donor areas of the medial and lateral patellar groove provided constant enhanced material properties, matrix synthesis rates and histological appearance compared to samples from the arthritic lesions of the MFC, even in joints with end-stage osteoarthritis of the MFC. No significant difference was found between patellar groove cartilage samples harvested from joints with different stages of osteoarthritis. Our findings demonstrate that healthy appearing cartilage from the patellar groove does not undergo significant alterations in material properties due to the arthritic milieu present in osteoarthritic joints. Accordingly these locations provide a source of functional tissue for transplant procedures even in joints with end-stage osteoarthritis.