PATELLAR TENDON DEFECT DURING THE FIRST-YEAR AFTER ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION - APPEARANCE ON SERIAL MAGNETIC-RESONANCE-IMAGING

The purpose of this study was to use magnetic resonance imaging to eva luate various parameters of the patellar tendon during the first year after harvest for anterior cruciate ligament (ACL) reconstruction. Twe lve consecutive patients were serially imaged on a 1.5 Tesla GE magnet (GE Medical Systems, Milwaukee, WI) with a dedicated knee coil at 3 w eeks, 3 months, 6 months, and 1 year after undergoing ACL reconstructi on using a central one-third patellar tendon autograft. The tendon def ect was not closed primarily, but the paratenon was approximated. The following measurements were performed: tendon width, defect width, cro ss-sectional area of the tendon, and tendon length. In addition, the p atellar bone harvest site was evaluated for healing. The width of the tendon defect decreased by 62% over 12 months (P < .05). Only two pati ents showed complete closure of the defect. Tendon width was noted to decrease by 6.5% (P = .017). The ratio of defect width to overall tend on width (designated R) decreased by 58% (P < .05). Tendon length was noted to decrease during this by 8% (P = .037). The tendon cross-secti onal area was noted to increase by 9% at 1 year, but this was not foun d to be statistically significant (P = .39). One year after ACL recons truction using a central one-third patellar tendon, the tendon defect has begun to reconstitute itself but there is still a significant gap. This persistent defect must be taken into consideration when planning revision ACL surgery using reharvest of the central one third of the patellar tendon. The entire tendon also exhibits a reduction in width and length, while cross-sectional area increases slightly. Complete he aling of the graft defect can not be assumed at 12 months post-ACL rec onstruction.