626 - Knee muscle strength after reconstruction of the anterior cruciate ligament (ACL) with patellar or hamstring autografts.

Thursday, February 19, 2026

5:00 PM - 6:30 PM AST

Presenting Author(s)

JF

Jeronimo J. Ferriol Alonso, MD, MS

Resident Physician
University of Puerto Rico School of Medicine
San Juan, Puerto Rico, United States

Co-Author(s)

JG

Jan I. Garcia-Rivera, MD

Resident Physician
University of Puerto Rico School of Medicine
San Juan, Puerto Rico, United States
CO

Claudia E. Otero-Fernandez, n/a

Undergraduate Student
University of Puerto Rico - Rio Piedras Campus
San Juan, Puerto Rico, United States
AP

Angel L. Pabon, DrPH

Biostatistician
University of Puerto Rico School of Medicine
San Juan, Puerto Rico, United States
AR

Anita Rivera-Brown, PhD

Professor
University of Puerto Rico School of Medicine
San Juan, Puerto Rico, United States
WM

William F. Micheo, MD

Professor and Chair
University of Puerto Rico School of Medicine
San Juan, Puerto Rico, United States
WF

Walter R. Frontera, MD, PhD, FRCP

Professor
University of Puerto Rico School of Medicine
San Juan, Puerto Rico, United States

Submitter(s)

JF

Jeronimo J. Ferriol Alonso, MD

Department of Physical Medicine, Rehabilitation & Sports Medicine, University of Puerto Rico School of Medicine
Ponce, Puerto Rico, United States

Objectives: The ACL is a major knee stabilizer that is frequently injured in sports. ACL reconstruction (ACL-R) is commonly done with a patellar (P) or hamstring (H) tendon autograft. After ACL-R, muscle weakness may be related to the type of autograft used. The purpose of this study was to compare limb muscle strength symmetry after ACL-R in patients with either P or H autograft.

Design: A cross-sectional retrospective study of athletes who underwent ACL-R between 2008 and 2024. Demographic and clinical data were acquired from testing reports. Isokinetic testing of the knee extensors and flexors was performed at 60 deg/s. In athletes with multiple tests, the first test was used. The primary outcome was the limb symmetry index (LSI) calculated as the highest torque of the ACL-R limb divided by the highest torque of the non-injured limb. An LSI >90% was considered acceptable. The data was analyzed with paired-sample t-test.

Results: 133 athletes were tested (P = 76 (57%) and H = 56 (43%); females = 62 (47%)). Overall mean age at the time of injury: 17.7 ± 4.8 years, time from injury to surgery: 3.8 ± 6.3 months, and time from surgery to test: 11.3 ± 8.3 months, with no difference between groups. Knee extensors strength was lower (P < 0.005) in ACL-R limb in both groups (P: 181.1 ± 47.3 vs. 133.1 ± 46.2; H: 190.3 ± 54.1 vs. 161.8 ± 54.4). Knee extensors LSI was lower in P (73.9 ± 18.0 %) compared to H (85.1 ± 14.5 %), P</span> < 0.05. Knee flexors LSI was acceptable in both groups (P = 98.6 ± 14.5; H = 92.0 ± 13.7, P</span> < 0.05).

Conclusions: ACL-R is associated with knee extensor strength asymmetry regardless of autograft. Emphasizing knee extensor strengthening in rehabilitation may accelerate return to sports and improve functional outcomes.