Tissue engineering for total meniscal substitution: animal study in sheep model.
OBJECTIVE
The aim of the study was to investigate the use of a novel hyaluronic acid/polycaprolactone material for meniscal tissue engineering and to evaluate the tissue regeneration after the augmentation of the implant with expanded autologous chondrocytes. Two different surgical implantation techniques in a sheep model were evaluated.


METHODS
Twenty-four skeletally mature sheep were treated with total medial meniscus replacements, while two meniscectomies served as empty controls. The animals were divided into two groups: cell-free scaffold and scaffold seeded with autologous chondrocytes. Two different surgical techniques were compared: in 12 animals, the implant was sutured to the capsule and to the meniscal ligament; in the other 12 animals, also a transtibial fixation of the horns was used. The animals were euthanized after 4 months. The specimens were assessed by gross inspection and histology.


RESULTS
All implants showed excellent capsular ingrowth at the periphery. Macroscopically, no difference was observed between cell-seeded and cell-free groups. Better implant appearance and integrity was observed in the group without transosseous horns fixation. Using the latter implantation technique, lower joint degeneration was observed in the cell-seeded group with respect to cell-free implants. The histological analysis indicated cellular infiltration and vascularization throughout the implanted constructs. Cartilaginous tissue formation was significantly more frequent in the cell-seeded constructs.


CONCLUSIONS
The current study supports the potential of a novel HYAFF/polycaprolactone scaffold for total meniscal substitution. Seeding of the scaffolds with autologous chondrocytes provides some benefit in the extent of fibrocartilaginous tissue repair.
Kon
Elizaveta
E
Laboratorio di Biomeccanica, Rizzoli Orthopedic Institute, Bologna, Italy. e.kon@biomec.ior.it
Chiari
Catharina
C
Marcacci
Maurilio
M
Delcogliano
Marco
M
Salter
Donald M
DM
Martin
Ivan
I
Ambrosio
Luigi
L
Fini
Milena
M
Tschon
Matilde
M
Tognana
Enrico
E
Plasenzotti
Roberto
R
Nehrer
Stefan
S
D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology / Q000637:transplantation; D019902:Chondrocytes / Q000637:transplantation; D005260:Female; D020007:Implants, Experimental; D007596:Joints / Q000473:pathology; D008592:Menisci, Tibial / Q000502:physiology* / Q000601:surgery*; D008855:Microscopy, Electron, Scanning; D023421:Models, Animal; D016062:Porosity; D012756:Sheep; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds