Soft tissue attachment of a filamentous carbon-absorbable polymer tendon and ligament replacement

Soft tissue structures can be replaced by a filamentous carbon-polylactic acid polymer tissue scaffold. A successful replacement requires a secure bond between the synthetic material and living soft tissue. This attachment has been investigated in a rabbit model. In 23 male, white New Zealand rabbits, the proximal third of the Achilles tendon of the hind leg was resected. Seventeen of these rabbits received composite tendon implants; six received no implants and served as shams. In all cases, the contralateral limb served as a unoperated control. Biological fixation of the synthetic material to the tendinous and myotendinous tissues of the rabbit gastrocnemius system was achieved. This occurred by ingrowth of soft tissue into the 7 mu carbon fiber network. This bond developed rapidly and was mechanically secure under physiologic loading conditions. The anastomoses' strengths were tested in tension over a 12-week period and compared to the breaking strengths of their contralateral, unoperated gastrocnemius systems and the sham systems. After four weeks, the systems with implants had strengths equivalent to those of the unoperated systems. Sham systems were significantly weaker throughout the test period. Histologically, the ingrowth process was associated with little inflammatory response. The ingrown tissue was found to be highly cellular with collagen oriented longitudinally to the tendon. After 12 weeks, the volume of collagenous tissue making up the regrown tendon section appeared nearly normal. Secure biological fixation of the carbon-polylactic acid scaffold to soft tissues may allow it application in repair or replacement of tendon or ligament deficits.