Anterior Cruciate Ligament Patellar Tendon Autograft Fixation at 0° Versus 30° Results in Improved Activity Scores and a Greater Proportion of Patients Achieving the Minimal Clinical Important Difference For Knee Injury and Osteoarthritis Outcome Score Pain: A Randomized Controlled Trial

Arthroscopy. 2022 Jun;38(6):1969-1977. doi: 10.1016/j.arthro.2021.12.018. Epub 2021 Dec 22.


Purpose: The aim of the current study was to determine the effect of the knee flexion angle (KFA) during tibial anterior cruciate ligament (ACL) graft fixation on patient-reported outcomes, graft stability, extension loss, and reoperation after anatomic single-bundle ACL reconstruction.

Methods: All 169 included patients (mean age 28.5 years, 65% male) were treated with anatomic single-bundle ACL reconstruction using patellar tendon autograft and were randomized to tibial fixation of the ACL graft at either 0° (n = 85) or 30° (n = 84). The primary outcome was the Knee Injury and Osteoarthritis Outcome Score (KOOS) 2 years after surgery. Secondary outcomes were the Marx Activity Scale (MAS), the rate of reoperation, and physical examination findings at 1 year, including KT-1000 and side-to-side differences in knee extension.

Results: The follow-up rate was 82% (n = 139) for the primary outcome. Graft failure rate at 2 years was 1% (n = 2, 1 per group). ACL tibial graft fixation at 0° or 30° did not have a significant effect on KOOS scores at 2 years after ACLR. Patients whose graft was fixed at a knee flexion angle of 0° had greater scores on the MAS (mean 9.6 95% confidence interval [CI] 8.5 to 10.6, versus 8.0, 95% CI 6.9 to 9.1; P = .04), and a greater proportion achieved the minimal clinical important difference (MCID) for the KOOS pain subdomain (94% versus 81%; P = .04). There was no significant difference in knee extension loss, KT-1000 measurements, or reoperation between the 2 groups.

Conclusion: In the setting of anatomic single-bundle ACLR using patellar tendon autograft and anteromedial portal femoral drilling, there was no difference in KOOS scores between patients fixed at 0° and 30°. Patient fixed in full extension did demonstrate higher activity scores at 2 years after surgery and a greater likelihood of achieving the MCID for KOOS pain.

Level of evidence: II, prospective randomized trial.

Trial registration: NCT03875807.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anterior Cruciate Ligament / surgery
  • Anterior Cruciate Ligament Injuries* / surgery
  • Autografts
  • Female
  • Humans
  • Knee Joint / surgery
  • Male
  • Osteoarthritis*
  • Pain
  • Patellar Ligament* / transplantation
  • Prospective Studies

Associated data