In Vitro Cell Quality of Articular Chondrocytes Assigned for Autologous Implantation in Dependence of Specific Patient Characteristics

Objective: Autologous chondrocyte implantation (ACI) is a well-established therapeutic option for the treatment of cartilage defects of the knee joint. Since information concerning the cellular aspects of ACI is still limited, the aim of the present study was to investigate relevant differences between chondrocyte quality after in vitro cultivation and possible correlations with patient-specific factors.

Design: Cell quality of 252 consecutive ACI patients was assessed after chondrocyte in vitro expansion by determination of the expression of cartilage relevant surface marker CD44 and cartilage-specific differentiation markers (aggrecan and collagen type II). All cell quality parameters were correlated with patient-specific parameters, such as age, size and defect location, number of defects and grade of joint degeneration according to the Kellgren-Lawrence classification.

Results: Neither the expression of CD44, aggrecan or collagen type II nor cell density or viability after proliferation seemed to correlate with the grade of joint degeneration, defect aetiology or patient gender. However, chondrocytes harvested from the knee joints of patients at less than 20 years of age showed significantly higher expression rates of cartilage-specific markers when compared to older patients' chondrocytes.

Conclusions: The present study identifies relevant differences concerning chondrocyte quality after in vitro expansion in a highly preselected study population of 252 patients that from a surgical point of view were eligible for ACI. With the exception of patients aged 20 years or younger, no patient-specific parameters could be identified which might allow anticipation of cell quality in individual patients.