A comparative study of the healing of tendon autograft and tendon-bone autograft using patellar tendon in rabbits

In order to compare the healing of tendon to bone and the healing of bow to bone in a rabbit model, the lateral 4 mm of patellar tendons were detached from their insertion into the tibia either subperiosteally (group I) or wi th a bone block (group II) and implanted into drill holes in the proximal a rticular surface of the tibia. The histological and biomechanical features of the graft incorporation were observed at 2, 4, 8 and 12 weeks. Histologi cal patterns similar to normal tendon-bone attachment were seen at the tend on-bone interface in group I by 12 weeks, while direct bony union was seen in group II by 8 weeks. The maximum tensile load and stiffness were signifi cantly greater in group II at 4 and 8 weeks while the difference between th e two groups was not significant at 2 and 12 weeks. These findings show tha t more rapid incorporation of the graft occurs in group II although no sign ificant difference in biomechanical parameters was noted once healing was c omplete.