This prospective observational study will compare recovery after anterior cruciate ligament reconstruction using quadriceps tendon autograft or hamstring tendon autograft. The main goal is to examine differences in knee muscle strength recovery during the early and mid-term postoperative period. Participants aged 13 to 45 years who undergo unilateral ACL reconstruction and meet the eligibility criteria will be followed at Hacettepe University. Knee extensor and flexor strength will be assessed using isometric testing at postoperative weeks 4, 8, and 12 and month 6, and with isokinetic concentric testing at months 3 and 6. Functional outcomes and kinesiophobia will also be evaluated at month 6 using IKDC, KOOS, and the Tampa Scale for Kinesiophobia. All participants will receive the same standard postoperative rehabilitation program under physiotherapist supervision. The study aims to clarify whether graft type is associated with different patterns of muscle strength recovery and functional improvement after ACL reconstruction
Age 13 to 45 years
Undergoing anterior cruciate ligament reconstruction with either hamstring tendon autograft or quadriceps tendon autograft
Unilateral anterior cruciate ligament injury
Complete ACL tear with accompanying minimal collateral ligament injury and first-degree meniscal tear
Anterior cruciate ligament reconstruction with patellar tendon autograft or allograft
Revision surgery
Systemic or neurological disease
Multiple ligament injuries
Participants will be patients with anterior cruciate ligament reconstruction using either quadriceps tendon autograft or hamstring tendon autograft who are referred by an orthopedist to the Hacettepe University Sports Health Unit, meet the eligibility criteria, and provide voluntary consent
Cohort
Prospective
Not listed
Isometric Quadriceps Muscle Strengt
Maximum voluntary isometric quadriceps strength measured with an IsoMed 2000 dynamometer at 60° of knee flexion. The highest value from 3 maximal 5-second contractions will be recorded and normalized to body weight (Nm/kg).
Isometric Hamstring Muscle Strength
Maximum voluntary isometric hamstring strength measured with an IsoMed 2000 dynamometer at 60° of knee flexion. The highest value from 3 maximal 5-second contractions will be recorded and normalized to body weight (Nm/kg)
Concentric Quadriceps- Hamstring Peak Torque at 60°/s and 180°/s
Concentric quadriceps and hamstring peak torque measured with an IsoMed 2000 dynamometer during isokinetic testing at 60°/s for 5 repetitions and 180°/s for 15 repetitions. Values will be normalized to body weight (Nm/kg).
Limb Symmetry Index
Limb Symmetry Index calculated from isokinetic peak torque values as operated limb / contralateral limb × 100.
International Knee Documentation Committee Subjective Knee Form Score
Patient-reported knee symptoms, function, and sports activity assessed using the IKDC Subjective Knee Form. Scores range from 0 to 100, with higher scores indicating better knee function.
Knee Injury and Osteoarthritis Outcome Score
Patient-reported knee outcomes assessed using the KOOS, including pain, symptoms, activities of daily living, sport and recreation, and knee-related quality of life. Scores range from 0 to 100, with higher scores indicating better status.
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