Two-year postoperative MRI appearances of anterior cruciate ligament hamstrings autografts are not correlated with functional outcomes, anterior laxity, or patient age

Abstract

Aims MRI has been suggested as an objective method of assessing anterior crucate ligament (ACL) graft “ligamentization” after reconstruction. It has been proposed that the MRI appearances could be used as an indicator of graft maturity and used as part of a return-to-sport assessment. The aim of this study was to evaluate the correlation between MRI graft signal and postoperative functional scores, anterior knee laxity, and patient age at operation. Methods A consecutive cohort of 149 patients who had undergone semitendinosus autograft ACL reconstruction, using femoral and tibial adjustable loop fixations, were evaluated retrospectively postoperatively at two years. All underwent MRI analysis of the ACL graft, performed using signal-to-noise quotient (SNQ) and the Howell score. Functional outcome scores (Lysholm, Tegner, International Knee Documentation Committee (IKDC) subjective, and IKDC objective) were obtained and all patients underwent instrumented side-to-side anterior laxity differential laxity testing. Results Two-year postoperative mean outcome scores were: Tegner 6.5 (2 to 10); Lysholm 89.8 (SD 10.4; 52 to 100); and IKDC subjective 86.8 (SD 11.8; 51 to 100). The objective IKDC score was 86% A (128 patients), 13% B (19 patients), and 1% C (two patients). Mean side-to-side anterior laxity difference (134 N force) was 0.6 mm (SD 1.8; -4.1 to 5.6). Mean graft SNQ was 2.0 (SD 3.5; -14 to 17). Graft Howell scores were I (61%, 91 patients), II (25%, 37 patients), III (13%, 19 patients), and IV (1%, two patients). There was no correlation between either Howell score or SNQ with instrumented anterior or Lysholm, Tegner, and IKDC scores, nor was any correlation found between patient age and ACL graft SNQ or Howell score. Conclusion The two-year postoperative MRI appearances of four-strand, semitendinosus ACL autografts (as measured by SNQ and Howell score) do not appear to have a relationship with postoperative functional scores, instrumented anterior laxity, or patient age at surgery. Other tools for analysis of graft maturity should be developed. Cite this article: Bone Jt Open 2021;2(8):569–575.

Anterior cruciate ligament autograft maturation on sequential postoperative MRI is not correlated with clinical outcome and anterior knee stability

“…Accordingly, changes in MRI signal of the ACL graft can be observed due to ultrastructural changes of graft over time. Previously, research on ACL autograft maturation used different MRI measurement methods, such as the signal/noise quotient (SNQ) [ 6 , 8 , 12 , 17 , 21 , 26 , 38 , 48 ], signal intensity ratio (SIR) [ 11 ], or T2 mapping [ 3 , 9 , 16 , 24 , 45 ]. In the present study, the graft signal intensity on MRI was normalized to the subject-specific signal intensity of both the PCL and the gastrocnemius muscle in order to minimize inter-scan variability.…”

“…However, current studies evaluating the MRI signal changes of ACL autografts and their correlation to clinical outcome and knee laxity remain inconclusive [ 6 , 12 , 16 , 17 , 35 ]. It is further unknown how ACL autograft MRI signal changes compare to a native ACL MRI signal [ 11 , 12 , 16 , 17 , 24 ].…”

Identifying Clinical and MRI Characteristics Associated with Quality of Life in Patients with Anterior Cruciate Ligament Injury: Prognostic Factors for Long-Term

“…Functional outcome score (The International Knee Documentation Committee (IKDC) score) was obtained and considered the main clinical outcome variable. The IKDC evaluation form is a validated instrument to record the clinical state of ACL reconstructed patients at one time [ 27 , 28 ]. The IKDC scores form was used to measure QOL in our statistical analysis.…”

Magnetic Resonance Imaging Assessment of Hamstring Graft Healing and Integration 1 and Minimum 2 Years after ACL Reconstruction

“…A recent study concluded that 2-year MRI results had no correlation with functional outcome, anterior laxity, or patient age, but the study did not report graft rupture. 3 A link has also been demonstrated between graft signal and bone tunnel appearance; an MRI study of 22 patients over the course of 2 years demonstrated a correlation between femoral tunnel widening and higher graft signal. Detailed analysis of the entire tunnel shape found the strongest correlation at the femoral aperture of the tunnel.…”

“…A recent study concluded that 2-year MRI results had no correlation with functional outcome, anterior laxity, or patient age, but the study did not report graft rupture. 3…”