Does the patellar tendon normalize after harvesting its central third?: a prospective long-term MRI study.

Background: The central third of the patellar tendon is the most frequently used autograft for ACL reconstruction.

Hypothesis: The patellar tendon at the donor site would look normal as seen on MRI 6 years after harvesting its central third.

Methods: Nineteen consecutive patients were included in the study. MRI examinations of the donor site were performed at 6 (5 to 10) weeks, 6 (6 to 8) months, 27 (24 to 29) months, and 71 (68 to 73) months postoperatively. The contralateral normal side was examined only on the first occasion.

Results: The size of the donor-site gap decreased significantly (P = 0.0001) between 6 weeks and 6 years. In most patients, a thinning of the central part of the patellar tendon was still found at 6 years. The thickness of the peripheral patellar tendon was increased, compared with the contralateral healthy side, until 2 years (P = 0.003). On all occasions, the width was increased compared with the contralateral side (P < 0.015).

Conclusion: Prospective MRI examinations revealed that the patellar tendon at the donor site had not normalized 6 years after harvesting its central third. The reharvesting of the patellar tendon can therefore not be recommended.