In vivo performance of a novel silk fibroin scaffold for partial meniscal replacement in a sheep model.
OBJECTIVE
Due to the negative effects of meniscectomy, there is a need for an adequate material to replace damaged meniscal tissue. To date, no material tested has been able to replace the meniscus sufficiently. Therefore, a new silk fibroin scaffold was investigated in an in vivo sheep model.


METHODS
Partial meniscectomy was carried out to the medial meniscus of 28 sheep, and a scaffold was implanted in 19 menisci (3-month scaffold group, n = 9; 6-month scaffold group, n = 10). In 9 sheep, the defect remained empty (partial meniscectomy group). Sham operation was performed in 9 animals.


RESULTS
The silk scaffold was able to withstand the loads experienced during the implantation period. It caused no inflammatory reaction in the joint 6 months postoperatively, and there were no significant differences in cartilage degeneration between the scaffold and sham groups. The compressive properties of the scaffold approached those of meniscal tissue. However, the scaffolds were not always stably fixed in the defect, leading to gapping between implant and host tissue or to total loss of the implant in 3 of 9 cases in each scaffold group. Hence, the fixation technique needs to be improved to achieve a better integration into the host tissue, and the long-term performance of the scaffolds should be further investigated.


CONCLUSIONS
These first in vivo results on a new silk fibroin scaffold provide the basis for further meniscal implant development. Whilst more data are required, there is preliminary evidence of chondroprotective properties, and the compressive properties and biocompatibility are promising.
Institute of Orthopaedic Research and Biomechanics, Centre of Musculoskeletal Research, University of Ulm, Helmholtzstraße 14, 89081, Ulm, Germany.
Katharina
K
Gruchenberg
Institute of Orthopaedic Research and Biomechanics, Centre of Musculoskeletal Research, University of Ulm, Helmholtzstraße 14, 89081, Ulm, Germany.
Anita
A
Ignatius
Department of Trauma and Orthopaedic Surgery, Centre of Musculoskeletal Research, Hospital of the Federal Armed Forces Ulm, 89081, Ulm, Germany.
Benedikt
B
Friemert
Department of Trauma and Orthopaedic Surgery, Centre of Musculoskeletal Research, Hospital of the Federal Armed Forces Ulm, 89081, Ulm, Germany.
Falk
F
von Lübken
Orthox Ltd., Abingdon, OX14 3HG, UK.
Nick
N
Skaer
Division of Biomaterials and Tissue Engineering, Eastman Dental Institute, University College London, London, WC1X 8LD, UK.
Kris
K
Gellynck
Centre for Orthopaedic and Sports Medicine, 8047, Zurich, Switzerland.
Oliver
O
Kessler
Institute of Orthopaedic Research and Biomechanics, Centre of Musculoskeletal Research, University of Ulm, Helmholtzstraße 14, 89081, Ulm, Germany. lutz.duerselen@uni-ulm.de.
Lutz
L
Dürselen
D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D005349:Fibroins; D007718:Knee Injuries / Q000601:surgery*; D007719:Knee Joint / Q000601:surgery*; D008592:Menisci, Tibial / Q000601:surgery*; D019736:Prostheses and Implants; D012756:Sheep; D034561:Sheep, Domestic; D000070600:Tibial Meniscus Injuries; D054457:Tissue Scaffolds
D005349:Fibroins