Introduction: Osteochondral lesions of the talus (OCL III–IV°) need both extensive debridement for revitalisation and osteochondral reconstruction of the joint surface. This can be achieved by autologous cancellous bone-grafting and combination with a cell-free bioresorbable collagen-I/III scaffold. Our first results with this technique are presented.

Methods: 25 patients (13 female, 12 male, mean age 30.9 years) with 26 osteochondral lesions of the talus (OCL III–IV°, 15 right, 11 left, 24 medial, 2 lateral, 1 bilateral case) were treated by minimal-invasive debridement, autologous cancellous bone-grafting and application of a porcine collagen-I/III scaffold (ChondroGide^®) and evaluated prospectively by clinical scoring and MRI. The average follow-up was 23.2 (6–36) months. The mean defect size was 2.0 cm², the mean depth 0.7 cm. 14 defects have had at least one (1–3) operation on the defect before. By the use of a distractor a malleolar osteotomy could be avoided in all cases.

Results: The AOFAS-score increased from 67.4 ± 12.2 to 89.5 ± 7.4 points (p< 0.01, t-test). On a visual 10-point scale pain decreased significantly from 6.2 to 1.7 while subjective ankle function improved from a mean of 4.4 ± 1.9 to 7.2 ±1.5. The results were rated excellent in 10/26 cases (38.4%), good in 14/26 (53.8) and fair in 2/26 (7.8%) cases. MRI follow-ups showed a complete or nearly complete defect filling. In two ankles a second-look arthroscopy unveiled the defects filled completely by a regenerative tissue with a smooth surface and good bonding. Full-core biopsies showed a mixed, mostly fibrocartilagenous tissue.

Conclusion: By combination of cancellous bone-grafting with a cell-free collagen-I/III scaffold typical osteochondral lesions of the talus can be adressed effectively in a minimal-invasive one-step procedure. By utilizing mesenchymal stem cells (MSC) for an autogenous reparation process the use of expensive cultured chondrocytes is not necessary. The results concerning clinical functional improvement, pain reduction and patients’ satisfaction as well as defect filling in MRI are promising.

Introduction: Bone-marrow stimulating techniques like microfracturing for focal chondral defects of the knee joint are widespread utilizing mesenchymal stem cells (MSC) for an autogenous reparation process. Microfracturing shows good results for smaller defects up to 2cm² while larger defects tend to an early secondary degeneration. Autologous Matrix Induced Chondrogenesis (AMIC®) combines microfracturing with application of a porcine collagen type-I/III bilayer matrix to host the MSC and to stabilize the blood clot.

Methods: 32 patients (25m, 7f, mean age 37.4y (18–52y)) with 35 focal chondral defects of the knee joint (ICRS III–IV°) of the condyle, trochlea and/or patella were treated by standardized microfracturing and application of a collagen matrix (Geistlich Biomaterials, Wolhusen, Switzerland). The outcome was evaluated prospectively by clinical scores and MRI with a follow-up of 6 to 24 months. The mean defect size was 3.86 cm² (1.0 – 6.8 cm²). 22 patients (68%) had at least one operation (1–8) on the knee before. 9 defects were caused by trauma. All 7 patients with osteochondritis dissecans had an autologous bone grafting. In 5 patients an ACL stabilization was performed simultaneously.

Results: All patients considered their knee as abnormal (ICRS III° (70%)) or severely abnormal (ICRS IV° (30%)) preoperatively according to the ICRS functional status. The Cincinnati-Score improved from 52.9 to 81.1 points while the Lysholm-Score rose from 60.4 to 85.9 points (each p< 0.001). Pain decreased significantly from 6.1 to 2.2 (10=max.) on the visual analogue scale. 4 biopsies (4–21 months) revealed reasonable results with regard to surface formation, filling and integration in the Brittberg score (∅10.25 pts., 12 pts.=max.) The MRI follow-ups showed an adequate filling of the defect, no prolonged effusion occured.

Conclusion: Microfracturing in combination with a collagen matrix (AMIC®) is a minimal invasive, effective technique for the repair of focal cartilage defects of the knee joint. Not using cultured chondrocytes it can be performed cost-effectively as a single-step procedure. Both primary and secondary treatments are possible. The first results concerning clinical functional improvement, pain reduction and patients’ satisfaction as well as defect filling in MRI are promising.