Table 2.

Comparison of the biomechanical properties of different cartilage repair methods.

Study	Operative Technique	Tissue Type	Measurement System	Biomechanical Results	Additional Findings
Ebenstein et al. [223]	MFx	Animal model—rabbits	Nanoindentation	Stiffness 0.03 ± 0.01 kN m−1—fibrous repair 0.17 ± 0.039 kN m−1—normal cartilage
Nakaji et al. [239]	OATS	Animal model—rabbits	Tactile frequency	Stiffness 107,695.1 ± 11,610.1 N/m2 after procedure; 95,386.8 ± 2689.4 after 1 week; 92,899.3 ± 3748.2 after 3 weeks; 95,969.8 ± 2157.1 N/m2 after 8 weeks; 104,683.7 ± 3311.5 N/m2 after 12 weeks 100,027.5 ± 396.4 N/m2—normal cartilage	Increase in bone trabeculae inside the subchondral region.
Kuroki et al. [240]	OATS	Animal model—porcine	Ultrasonic	Stiffness 9.2 ± 1.78 (before harvesting) and 9.0 ± 1.91 (after grafting) [corresponding values]—6 mm plug model 5.8 ± 1.54 (before harvesting) and 5.8 ± 1.87 (after grafting)—5 mm plug model	Changes in stiffness are more likely related to the healing or remodeling process rather than to the surgical procedure
Lane et al. [241]	OATS	Animal model—goats	Indentation	Stiffness 5.29 ± 1.04 N/mm—transferred plugs after 12 weeks 0.79 ± 0.15 N/mm—normal cartilage	In total, 95% of the cells counted manually by confocal microscopy were viable 12 weeks after transfer
Nam et al. [242]	OATS	Animal model—rabbits	Indentation	Stiffness 1213.6 ± 309.0 N/mm—12 weeks after transplant 483.1 ± 229.1 N/mm—6 weeks after transplant 774.8 ± 117.1 N/mm—normal cartilage	Modified O’Driscoll Histological Score (24 points max): 6-week OAT, 21.6 ± 1.3; 12-week OAT, 21.0 ± 1.8; 6-week full-thickness defects, 11.5 ± 2.8; 12-week full-thickness defects, 10.8 ± 4.4
Hangody et al. [237]	OATS	Human	Arthroscopic Indentation	Stiffness Stiffness of the resurfaced area similar to the surrounding hyaline cartilage (no numerical data)
Peterson et al. [250]	ACI	Human	Indentation	Stiffness 2.4 ± 0.3 N—grafted area 3.2 ± 0.3 N—normal cartilage 3.0 ± 1.1 N—mean value at hyaline repair 1.5 ± 0.35—mean value at fibrous repair
Vasara et al. [252]	ACI	Human	Indentation	Stiffness 2.04 ± 0.83 N—repair tissue 3.58 ± 1.04 N—normal cartilage
Henderson et al. [253]	ACI	Human	Arthroscopic Indentation	Stiffness 3 ± 1.5 N—maximum stiffness of the repair Avg. normalized stiffness—104% of the surrounding hyaline cartilage
Lee et al. [259]	MACI	Animal model—canine	Indentation	Aggregate modulus 15% of the native cartilage
Griffin et al. [261]	MACI	Animal model—equine	Custom tribometer	Avg. values of boundary mode friction coefficients—from 0.42 to 0.52 Shear modulus 0.2 to 0.5 MPa—repaired cartilage 1.0 to 1.5 MPa—normal cartilage
Franke et al. [220]	MACI (periosteal cells)	Animal model—miniature pigs	Nanoindentation	Stiffness 0.5 kN m−1—repaired cartilage 4.0 kN m−1—normal cartilage
Tanaka et al. [267]	Tissue Engineering	PLLA scaffolds	Indentation	Elastic moduli 3000–28,000 kPa