Combination of Filtered Bone Marrow Aspirate and Biomimetic Scaffold for the Treatment of Knee Osteochondral Lesions: Cellular and Early Clinical Results of a Single Centre Case Series

Osteochondral injury is a very common orthopaedic pathology, mainly affecting young, active population, with limited current treatment options. Herein we are presenting cellular and early clinical data of a patient series treated for chronic osteochondral lesions in the knee with a filter-based intra-operative bone marrow aspirate (BMA) separation device.

The filter-based BMA separation procedure significantly increased the frequency of mesenchymal stem/stromal cells (MSCs), however their concentration was not increased. The clinical evaluation revealed high safety profile of the treatment and resulted in improved clinical status of the patients.

Fifteen patients with chronic knee osteochondral lesions (60% females, 19-59 years) were included in this prospective case series. Filtered BMA (f-BMA), containing mesenchymal stem/stromal cells (MSCs), was combined with a biomimetic collagen-hydroxyapatite scaffold (CHAS) and implanted into the site of the lesion. Harvested BMA and post-separation f-BMA were analysed for blood cell counts, flow cytometry, and fibroblast colony forming units (CFU-Fs). Patients were followed for serious adverse events and graft failures. Clinical evaluation was assessed using the knee injury and osteoarthritis outcome score (KOOS). In 8 patients a magnetic resonance imaging (MRI)/arthroscopy were performed.

Cell suspension contained 0.027% CD271+ CD45- 7-AAD- cells, 0.15% CD73+ CD90+ CD105+ cells and 0.0012% CFU-Fs of all nucleated cells with 86% viability. Filtration process resulted in 12.8 (4.0-40.8) fold enrichment in terms of CFU-F content in comparison to initial BMA. No serious adverse events related directly to the osteochondral treatment were reported. After an average follow-up of 20 months (14-25) all KOOS subscales (Symptoms/Pain/Daily activities/Sport and recreation/Quality of life) increased significantly from pre-operative 55/56/67/30/30 to post-operative 73/76/79/51/52 (p values < 0.05), respectively. MRI or arthroscopic evaluation revealed nearly normal to normal overall International Cartilage Repair Society assessment in 7/8 patients.