Cell-free repair of small cartilage defects in the Goettinger minipig: which defect size is possible?
OBJECTIVE
Cartilage repair of full-thickness chondral defects in the knees of Goettinger minipigs was assessed by treatment with cell-free collagen type-I gel plugs of three different sizes.


METHODS
In 6 adult Goettinger minipigs, three full-thickness chondral defects were created in the trochlear groove of one knee of the hind leg. These defects were treated with a cell-free collagen type-I gel plug of 8, 10, or 12 mm diameter. All animals were allowed unlimited weight bearing. After 1 year, the animals were killed. Immediately after recovery, a non-destructive biomechanical testing was performed. The repair tissue quality was evaluated immunohistologically, collagen type-II protein was quantified, and a semiquantitative score (O'Driscoll score) was calculated.


RESULTS
After 1 year, a high number of cells migrated into the initially cell-free collagen gel plugs and a hyaline-like repair tissue had been created. The O'Driscoll scores were: 8 mm, 21.2 (SD, 2.8); 10 mm, 21.5 (SD, 1.6); and 12 mm, 22.3 (SD, 1.0). The determination of the e-modulus, creep and relaxation revealed that mechanical properties of the two smaller defects were closer to unaffected hyaline cartilage.


CONCLUSIONS
As cell-free collagen type-I gel plugs of all three different sizes created hyaline-like repair tissue, this system seems suitable for the treatment of even larger defects.
Department of Orthopaedic and Trauma Surgery, Aachen University Hospital, Pauwelsstr. 30, 52074, Aachen, Germany. karstengavenis@gmx.de
K
K
Gavenis
U
U
Schneider
U
U
Maus
T
T
Mumme
R
R
Muller-Rath
Bernhard
B
Schmidt-Rohlfing
S
S
Andereya
D000818:Animals; D002356:Cartilage / Q000293:injuries* / Q000601:surgery*; D002465:Cell Movement; D024042:Collagen Type I / Q000008:administration & dosage*; D024043:Collagen Type II / Q000032:analysis; D048091:Guided Tissue Regeneration / Q000379:methods; D007150:Immunohistochemistry; D008297:Male; D008422:Materials Testing; D019637:Orthopedic Procedures / Q000379:methods; D013264:Stifle / Q000293:injuries / Q000601:surgery*; D013552:Swine; D013556:Swine, Miniature; D054457:Tissue Scaffolds
D024042:Collagen Type I; D024043:Collagen Type II