Clinical and MRI evaluation of medium- to long-term results after autologous osteochondral transplantation (OCT) in the knee joint

Abstract

Purpose: Autologous osteochondral transplantation (OCT) is one of the surgical options currently used to treat cartilage defects. It is the only cartilage repair method that leads to a transfer of hyaline cartilage repair tissue. The purpose of this study was to evaluate the magnetic resonance observation of cartilage repair tissue (MOCART) score, the 3D MOCART score and various clinical scores in patients after OCT in knee joints.

Methods: Two women and eight men were evaluated 6-9 years (median 7.2 years) after OCT on the femoral condyle of the knee joint. All patients were evaluated by magnetic resonance imaging (MRI) measurement, using a 3.0 T Scanner with different cartilage-specific sequences. Clinical assessment included the knee injury and osteoarthritis outcome score (KOOS), the international knee documentation committee (IKDC) subjective knee form, the Noyes sport activity rating scale and the Tegner activity score. For MRI evaluation, the MOCART score and 3D MOCART score were applied.

Results: Clinical long-term results after OCT showed median values of 77 (range 35.7-71.4) for the IKDC; 50 (6.3-100), 66.7 (30.6-97.2), 65 (0-75), 57.1 (35.7-71.4) and 80.9 (30.9-100) for the KOOS subscales (quality of life, pain sports, symptoms and activity of daily living); 61.4 (22.3-86.2) for the Noyes scale; and 3 (0-6) for the Tegner activity score. The median MOCART score was 75 (30-90) after both 1 and 2 years and 57.5 (35-90) after 7 years, as assessed by different cartilage-specific sequences. The 3D MOCART score showed values of 70 (50-85) and 60 (50-80) in the two different isotropic sequences after 7 years.

Conclusion: The MOCART and 3D MOCART scores are applicable tools for patient follow-up after OCT. Post-operative follow-up assessments would also benefit from the inclusion of OCT-specific parameters. Long-term results after OCT reflect an impairment in clinical scores in the first 2 years with good results during follow-up. Stable conditions were observed between 2 and 7 years after surgery. The filling of the defects and the cartilage interface appeared good at MRI evaluation after the first 2 years, but cartilage loss was observed between the medium- and long-term follow-ups. Isotropic imaging with multiplanar reconstruction is useful for daily clinical use to assess bony cylinders in cartilage repair, especially in combination with the 3D MOCART.

Level of evidence: Retrospective therapeutic study, Level IV.