ISAKOS Congress 2021

2021 ISAKOS Biennial Congress Paper


MRI After ACL Reconstruction Demonstrates that Hamstring Grafts Heal and Integrate at Different Rates

Sven Edward Putnis, MBChB, FRCS(Orth), Bristol UNITED KINGDOM
Takeshi Oshima, MD, PhD, Sydney, NSW AUSTRALIA
Antonio Klasan, MD, Linz AUSTRIA
Samuel Grasso, PhD, B. Engineering (Mechanical), Sydney, NSW AUSTRALIA
Thomas Neri, MD, PhD, Asst. Prof., Saint-Etienne FRANCE
Myles R. J. Coolican, FRACS, Sydney, NSW AUSTRALIA
Brett A. Fritsch, MBBS BSc(Med), FRACS, FAOrthA, Hunters Hill, NSW AUSTRALIA
David A. Parker, MBBS, BMedSc, FRACS, Sydney, NSW AUSTRALIA

Sydney Orthopaedic Research Institute, Sydney, NSW, AUSTRALIA

FDA Status Not Applicable


New MRI analysis at 1 and 2 years after ACL reconstruction demonstrates that hamstring grafts heal and integrate at different rates



To establish whether a hamstring ACL reconstruction graft changes in appearance on MRI between 1 and 2 years, and whether it affects a patient’s ability to return to sport.


Patients with a hamstring autograft ACL reconstruction using adjustable suspensory fixation had MRI and clinical outcome measures at 1 and minimum 2 years. Signal intensity ratio (SIR) at multiple areas using oblique reconstructions both parallel and perpendicular with the graft were calculated alongside tunnel aperture sizes. Clinical outcome was side to side anterior laxity, and patient reported outcome measures (PROMs).


Forty-two patients had full datasets. At 1 year the mean SIR for the graft was 2.7 +/- 1.2, with proximal graft signal significantly higher than distal. Overall, there was no significant change at by 2 years apart from those with the highest proximal graft signal (SIR > 4) at 1 year. This group had a reduction in signal and were also most likely to have a reduction in tunnel aperture area. The finding of tunnel aperture area reduction between 1 and 2 years was significant across the full cohort (mean tibial -6.9mm2, p< 0.001, mean femoral -13.5mm2, p< 0.001). A high patient sporting level was seen, with a median Tegner activity score of 6 [5-10], with a third of patients scoring either a 9 or 10. Overall, PROMs were not affected by MRI appearance.


In the majority of patients graft signal does not change after one year. However, a significant reduction is seen in those with high signal at one year. Tunnel contraction correlates with a reduction in graft SIR suggesting this could be a useful measure of graft integration.

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