Tendon Regeneration After Partial-Thickness Peroneus Longus Tendon Harvesting: Magnetic Resonance Imaging Evaluation and In Vivo Animal Study.

BACKGROUND: In recent years, the use of the anterior half of the peroneus longus tendon (AHPLT) as an autograft source for ligament reconstruction has gained popularity. However, no reports are available regarding tendon regeneration after harvesting of the AHPLT.

HYPOTHESIS: When half of the tendon is preserved during tendon harvesting, the quality of the regenerated tendon is better than that of the regenerated tendon after full-thickness harvesting.

STUDY DESIGN: Case series; Level of evidence, 4; controlled laboratory study.

METHODS: A total of 21 patients who underwent AHPLT harvesting for lower extremity ligament reconstruction participated in the magnetic resonance imaging (MRI) study to evaluate tendon regeneration 1 year after the harvesting. An in vivo animal study was performed to compare the quality of the regenerated tendon after partial-thickness and full-thickness tendon harvesting. A total of 30 adult female Sprague-Dawley rats were allocated to 2 groups-15 rats underwent partial-thickness Achilles tendon harvesting (partial-thickness harvesting [PTH] group), and 15 rats underwent full-thickness Achilles tendon harvesting (full-thickness harvesting [FTH] group). The quality of the regenerated tendons was compared 180 days after tendon harvesting.

RESULTS: All 21 patients showed regeneration of the peroneus longus tendon (PLT) (homogeneously dark on both T1- and T2-weighted sequences). The cross-sectional area of the regenerated tendon divided by that of the preoperative tendon was 92.6% and 84.5% at 4 cm and 9 cm proximal to the tip of the distal fibula, respectively. In the animal study, the mean histologic score was better for the PTH group compared with the FTH group (9.17 ± 1.35 vs 14.72 ± 0.74; P < .001). The ultimate strength and the stiffness of the regenerated Achilles tendon were significantly higher for the PTH group compared with the FTH group (35.5 ± 8.3 vs 22.4 ± 8.3 N, P = .004; and 31.6 ± 7.7 vs 23.5 ± 4.8 N/mm, P = .016).

CONCLUSION: The PLT was found to regenerate after partial-thickness harvesting on MRI. In the animal study, the quality of the regenerated tendon when half of the tendon was preserved during tendon harvesting was better than that after full-thickness tendon harvesting.