Magnetic resonance imaging of the patellar tendon after harvesting its central third: a comparison between traditional and subcutaneous harvesting techniques.

The aim of this study was to compare the 2-year results after anterior cruciate ligament reconstruction using patellar tendon autografts harvested through a paratenon-splitting, traditional technique (group A) with the results of a subcutaneous technique aiming at protecting the infrapatellar nerves and the paratenon (group B). Special emphasis was placed on evaluating the donor site. Magnetic resonance imaging (MRI) of the patellar tendon was performed to evaluate the reconstitution after harvesting its central third. Examinations of knee-walking ability and assessments of anterior knee sensitivity were made in order to evaluate donor-site discomfort and the function of infrapatellar nerves. Seventy-two consecutive patients were included in the study; group A comprised 35 patients and group B, 37 patients. At the 2-year follow-up, the Tegner activity level, the Lysholm score, and the IKDC evaluation system showed no significant differences between groups A and B. The median loss of normal anterior knee sensitivity was 16 cm2 (range, 0 to 200 cm2) in group A and 0 cm2 (range, 0 to 285 cm2) in group B (P = .20). In group A 20% of the patients and in group B 58% had normal sensitivity (P < .01). MRI showed that the donor-site gap (area corresponding to non-tendinous-like tissue signal) was 5 mm (range, 0 to 9 mm) in group A and 2 mm (range, 0 to 5 mm) in group B (P < .0001). At 2-year follow-up, the subcutaneous graft-harvesting technique resulted in less disturbance of anterior knee sensitivity and a smaller donor-site gap than the traditional technique.