Clinical and radiographical ten years long-term outcome of microfracture vs. autologous chondrocyte implantation: a matched-pair analysis

Abstract

Purpose: To compare the clinical and radiographical long-term outcome of microfracture (MFX) and first-generation periosteum-covered autologous chondrocyte implantation (ACI-P).

Methods: All subjects (n = 86) who had been treated with knee joint ACI-P or microfracture (n = 76) with a post-operative follow-up of at least ten years were selected. Clinical pre- and post-operative outcomes were analyzed by numeric analog scale (NAS) for pain, Lysholm, Tegner, IKDC, and KOOS score. Radiographical evaluation was visualized by magnetic resonance imaging (MRI). Assessment of the regenerate quality was performed by the magnetic resonance observation of cartilage repair tissue (MOCART) and modified knee osteoarthritis scoring system (mKOSS). Relaxation time (RT) of T2 maps enabled a microstructural cartilage analysis.

Results: MFX and ACI of 44 patients (24 females, 20 males; mean age 38.9 ± 12.1 years) resulted in a good long-term outcome with low pain scores and significant improved clinical scores. The final Lysholm and functional NAS scores were significantly higher in the MFX group (Lysholm: MFX 82 ± 15 vs. ACI-P 71 ± 18 p = 0.027; NAS function: MFX 8.1 ± 3.5 vs. ACI-P 6.0 ± 2.5; p = 0.003). The MOCART score did not show any qualitative differences. KOSS analysis demonstrated that cartilage repair of small defects resulted in a significant better outcome. T2-relaxation times were without difference between groups at the region of the regenerate tissue.

Conclusion: This study did not demonstrate coherent statistical differences between both cartilage repair procedures. MFX might be superior in the treatment of small cartilage defects.

Keywords: Knee osteoarthritis scoring system; Magnetic resonance observation of cartilage repair tissue; Microfracture; Periosteum-covered autologous chondrocyte implantation.