Trial Outcomes & Findings for Initial Graft Tension and ACL Surgery (NCT NCT00434837)

Results Overview

Medial joint space width measurements were obtained from radiographs preoperatively and postoperatively using the semiflexed metatarsophalangeal view. Radiographs were taken of each knee, and the medial compartment joint space width was measured by calculating the distance between the femoral and tibial intersections with the bisecting midpoint line. Analysis was conducted using a MATLAB program. (Mehta N, Duryea J, Badger GJ, et al. Comparison of 2 Radiographic Techniques for Measurement of Tibiofemoral Joint Space Width. Orthop J Sports Med. 2017;5(9):2325967117728675. Published 2017 Sep 26. doi:10.1177/2325967117728675) Subjects are identified as having radiographic signs of OA if they exhibit a change in the medial or lateral compartments greater than 0.30 mm over the study period. This was the first method used for the study. It was used for baseline and 3-year follow-up prior to switching to the 'surface-fit' method at the 7-year follow-up.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

168 participants

Primary outcome timeframe

3 years

Results posted on

2025-04-01

Participant Flow

Recruitment took place between February 2004 and February 2007 in clinics of participating doctors: Dr. Paul D. Fadale, Dr. Michael J. Hulstyn, and Dr. Robert M. Shalvoy.

Patients between the age of 15-50 with isolated unilateral ACL injuries were considered for eligibility. Patients were excluded from the study if they required meniscectomy greater than 1/3 of meniscus, showed increased laxity of knee ligaments, or had a history of previous knee injuries and/or developing osteoarthritis. Of 108 subjects initially recruited to tension groups, 18 were excluded pre- or during surgery.

Participant milestones

Participant milestones
Measure	Low-tension Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group Uninjured age, sex, and race matched control group
Overall Study STARTED	46	44	60
Overall Study 6 Months	39	37	0
Overall Study 1 Year	35	34	48
Overall Study 3 Years	44	41	48
Overall Study 7 Years	36	36	34
Overall Study 10-12 Years	32	28	35
Overall Study COMPLETED	26	21	30
Overall Study NOT COMPLETED	20	23	30

Reasons for withdrawal

Reasons for withdrawal
Measure	Low-tension Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group Uninjured age, sex, and race matched control group
Overall Study Lost to Follow-up	20	23	30

Baseline Characteristics

Control subjects did not undergo ACL reconstruction and were not included in the calculations. 5 patients in the high-tension group and 1 patient in the low-tension group did not report an exact injury date and are excluded from this variable.

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group	Total n=150 Participants Total of all reporting groups
Time from injury to surgery	112 days STANDARD_DEVIATION 86.5 • n=45 Participants • Control subjects did not undergo ACL reconstruction and were not included in the calculations. 5 patients in the high-tension group and 1 patient in the low-tension group did not report an exact injury date and are excluded from this variable.	116 days STANDARD_DEVIATION 119 • n=39 Participants • Control subjects did not undergo ACL reconstruction and were not included in the calculations. 5 patients in the high-tension group and 1 patient in the low-tension group did not report an exact injury date and are excluded from this variable.	—	114 days STANDARD_DEVIATION 102 • n=84 Participants • Control subjects did not undergo ACL reconstruction and were not included in the calculations. 5 patients in the high-tension group and 1 patient in the low-tension group did not report an exact injury date and are excluded from this variable.
Graft type Autologous Patellar Tendon	31 Participants n=46 Participants • Control patients did not undergo ACL reconstruction and therefore were not assigned a graft type.	27 Participants n=44 Participants • Control patients did not undergo ACL reconstruction and therefore were not assigned a graft type.	—	58 Participants n=90 Participants • Control patients did not undergo ACL reconstruction and therefore were not assigned a graft type.
Graft type Autologous Hamstring Tendon	15 Participants n=46 Participants • Control patients did not undergo ACL reconstruction and therefore were not assigned a graft type.	17 Participants n=44 Participants • Control patients did not undergo ACL reconstruction and therefore were not assigned a graft type.	—	32 Participants n=90 Participants • Control patients did not undergo ACL reconstruction and therefore were not assigned a graft type.
Age, Continuous	23.9 years STANDARD_DEVIATION 9.26 • n=46 Participants	23.1 years STANDARD_DEVIATION 7.19 • n=44 Participants	25.3 years STANDARD_DEVIATION 6.15 • n=60 Participants	24.2 years STANDARD_DEVIATION 7.53 • n=150 Participants
Sex: Female, Male Female	22 Participants n=46 Participants	26 Participants n=44 Participants	26 Participants n=60 Participants	74 Participants n=150 Participants
Sex: Female, Male Male	24 Participants n=46 Participants	18 Participants n=44 Participants	34 Participants n=60 Participants	76 Participants n=150 Participants
Race/Ethnicity, Customized White	43 participants n=46 Participants	36 participants n=44 Participants	52 participants n=60 Participants	131 participants n=150 Participants
Race/Ethnicity, Customized Black	0 participants n=46 Participants	2 participants n=44 Participants	1 participants n=60 Participants	3 participants n=150 Participants
Race/Ethnicity, Customized Asian	0 participants n=46 Participants	2 participants n=44 Participants	3 participants n=60 Participants	5 participants n=150 Participants
Race/Ethnicity, Customized Native Hawaiian or Other Pacific Islander	0 participants n=46 Participants	0 participants n=44 Participants	0 participants n=60 Participants	0 participants n=150 Participants
Race/Ethnicity, Customized More than one race	0 participants n=46 Participants	1 participants n=44 Participants	0 participants n=60 Participants	1 participants n=150 Participants
Race/Ethnicity, Customized Hispanic or Latino	2 participants n=46 Participants	3 participants n=44 Participants	3 participants n=60 Participants	8 participants n=150 Participants
Race/Ethnicity, Customized Unknown/Not Reported	1 participants n=46 Participants	0 participants n=44 Participants	1 participants n=60 Participants	2 participants n=150 Participants
Region of Enrollment United States	46 participants n=46 Participants	44 participants n=44 Participants	60 participants n=60 Participants	150 participants n=150 Participants
BMI	24.7 kg/m^2 STANDARD_DEVIATION 3.20 • n=46 Participants	24.5 kg/m^2 STANDARD_DEVIATION 3.56 • n=44 Participants	23.9 kg/m^2 STANDARD_DEVIATION 3.14 • n=60 Participants	24.3 kg/m^2 STANDARD_DEVIATION 3.28 • n=150 Participants

PRIMARY outcome

Timeframe: 3 years

Population: Insufficient time for imaging; loss to follow-up.

Medial joint space width measurements were obtained from radiographs preoperatively and postoperatively using the semiflexed metatarsophalangeal view. Radiographs were taken of each knee, and the medial compartment joint space width was measured by calculating the distance between the femoral and tibial intersections with the bisecting midpoint line. Analysis was conducted using a MATLAB program. (Mehta N, Duryea J, Badger GJ, et al. Comparison of 2 Radiographic Techniques for Measurement of Tibiofemoral Joint Space Width. Orthop J Sports Med. 2017;5(9):2325967117728675. Published 2017 Sep 26. doi:10.1177/2325967117728675) Subjects are identified as having radiographic signs of OA if they exhibit a change in the medial or lateral compartments greater than 0.30 mm over the study period. This was the first method used for the study. It was used for baseline and 3-year follow-up prior to switching to the 'surface-fit' method at the 7-year follow-up.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Radiographic Joint Space Narrowing (Midpoint Method) Baseline	0.0613 mm Interval -0.164 to 0.287	0.0634 mm Interval -0.126 to 0.253	-0.0321 mm Interval -0.185 to 0.121
Radiographic Joint Space Narrowing (Midpoint Method) 1-year	0.1374 mm Interval -0.042 to 0.317	0.1941 mm Interval 0.0342 to 0.354	-0.2413 mm Interval -0.409 to -0.074
Radiographic Joint Space Narrowing (Midpoint Method) 3-years	0.0705 mm Interval -0.07 to 0.211	0.0192 mm Interval -0.12 to 0.158	-0.1321 mm Interval -0.322 to 0.0575

PRIMARY outcome

Timeframe: 7 years

Population: Insufficient time for imaging; loss to follow-up. Baseline images of subjects presented at 7-year follow-up were analyzed again retroactively with this method.

Medial joint space width measurements were obtained from radiographs preoperatively and postoperatively using the semiflexed metatarsophalangeal view. Radiographs were taken of each knee, and the medial compartment joint space width was measured at the midline of the compartment in the coronal plane using a validated computer algorithm. (Duryea et al., Trainable rule-based algorithm for the measurement of joint space width in digital radiographic images of the knee, Medical Physics 27, 580 (2000); doi: 10.1118/1.598897). Subjects are identified as having radiographic signs of OA if they exhibit a change in the medial or lateral compartments greater than 0.30mm over the study period. The surface-fit method was used for the 7-year follow-up and baseline radiographs instead of the Midpoint Method, after confirming less variability across knees within a participant. (Mehta et al. 2017)

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Radiographic Joint Space Narrowing (Surface-Fit Method) Baseline	0.1483 mm Interval -0.0979 to 0.3944	0.0029 mm Interval -0.2001 to 0.2058	-0.0492 mm Interval -0.2041 to 0.1058
Radiographic Joint Space Narrowing (Surface-Fit Method) 7-years	0.1858 mm Interval -0.037 to 0.4086	0.1969 mm Interval -0.0855 to 0.4792	-0.2314 mm Interval -0.4259 to -0.0369

PRIMARY outcome

Timeframe: 15 years

Population: Insufficient time for imaging; loss to follow-up. Method was used retroactively for existing baseline images.

Joint space width measurements in the medial compartment were calculated from weightbearing radiographs using the semi-flexed metatarsophalangeal view. Radiographs were manually segmented to outline articular surfaces of femur and tibia using Mimics. A custom program in MATLAB developed by Dr. Ata Kiapour was used to calculate joint space width as the perpendicular distance between the femoral condyle and tibial plateau boundaries at 25% of total bicondylar width. Measured JSW values were then scaled using image distances between beads of a calibration standard taped to the fibular head. This method was used for the baseline, 10-12, and 15-year follow-up as a comparable in-house method to the surface-fit method. Subjects are identified as having radiographic signs of OA if they exhibit a change in the medial or lateral compartments greater than 0.30 mm over the study period.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Radiographic Joint Space Narrowing (Kiapour Method) Baseline	-0.1076 mm Interval -0.3421 to 0.1268	0.0653 mm Interval -0.1947 to 0.3254	-0.0876 mm Interval -0.3242 to 0.149
Radiographic Joint Space Narrowing (Kiapour Method) 10-12-year	-0.1038 mm Interval -0.6593 to 0.4516	0.3238 mm Interval -0.0686 to 0.7162	0.3269 mm Interval -0.1281 to 0.7819
Radiographic Joint Space Narrowing (Kiapour Method) 15-year	0.1136 mm Interval -0.5391 to 0.7664	0.5509 mm Interval -0.1457 to 1.2474	-0.1553 mm Interval -0.5961 to 0.2856

SECONDARY outcome

Timeframe: 15 years

Population: Some subjects omitted responses from questions pertaining to the symptoms score. These subjects were omitted from the overall N for score calculations. Loss to follow-up between time-points accounts for the remaining population differences. Control subjects were not assessed at 6 months.

The five dimensions of Knee Osteoarthritis Outcome Score were scored separately: pain , symptoms ,activities of daily life function, sport and recreation function, and knee-related quality of life . Each sub score has a 0-100 scale. 0- extreme knee problems and 100- no knee problems.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Symptoms 3-years	85.9073 score on a scale Interval 81.9161 to 89.8986	82.1429 score on a scale Interval 76.7482 to 87.5375	93.2234 score on a scale Interval 90.449 to 95.9979
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Symptoms 10-12-years	83.4110 score on a scale Interval 77.9542 to 88.8677	85.0257 score on a scale Interval 78.8811 to 91.1703	91.7351 score on a scale Interval 89.1559 to 94.3144
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Symptoms Baseline	70.3704 score on a scale Interval 65.631 to 75.11	70.4319 score on a scale Interval 65.012 to 75.852	96.7292 score on a scale Interval 95.697 to 97.756
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Symptoms 6 months	79.5168 score on a scale Interval 75.6389 to 83.3947	78.4184 score on a scale Interval 72.0655 to 84.7712	—
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Symptoms 1-year	84.1270 score on a scale Interval 80.1998 to 88.0542	80.0824 score on a scale Interval 75.0444 to 85.1205	95.8207 score on a scale Interval 94.4758 to 97.1655
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Symptoms 7-years	82.2421 score on a scale Interval 76.9068 to 87.5773	85.8135 score on a scale Interval 80.5316 to 91.0954	92.3319 score on a scale Interval 89.4216 to 95.2423
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Symptoms 15-years	84.2033 score on a scale Interval 78.8341 to 89.5725	83.1633 score on a scale Interval 77.3211 to 89.0054	92.6190 score on a scale Interval 89.0315 to 96.2066

SECONDARY outcome

Timeframe: 15 years

Population: Some subjects omitted responses from questions pertaining to the pain score. These subjects were omitted from the overall N for score calculations. Loss to follow-up between time-points accounts for the remaining population differences. Control subjects were not assessed at 6 months.

The five dimensions of Knee Osteoarthritis Outcome Score were scored separately: pain , symptoms ,activities of daily life function, sport and recreation function, and knee-related quality of life . Each sub score has a 0-100 scale. 0- extreme knee problems and 100- no knee problems.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Pain Baseline	75.3549 score on a scale Interval 70.8954 to 79.8145	77.0187 score on a scale Interval 72.5225 to 81.515	98.8889 score on a scale Interval 98.3103 to 99.4675
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Pain 6 months	86.6422 score on a scale Interval 83.0298 to 90.2545	86.2302 score on a scale Interval 80.3802 to 92.0801	—
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Pain 1-year	90.2317 score on a scale Interval 86.812 to 93.651	88.9245 score on a scale Interval 85.2901 to 92.5589	98.1679 score on a scale Interval 97.1089 to 99.2268
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Pain 3-years	90.6907 score on a scale Interval 86.8264 to 94.5549	91.0948 score on a scale Interval 87.6175 to 94.572	96.2963 score on a scale Interval 93.7527 to 98.84
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Pain 7-years	90.5671 score on a scale Interval 86.6955 to 94.4387	92.8241 score on a scale Interval 89.0008 to 96.6474	96.3848 score on a scale Interval 94.5122 to 98.2574
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Pain 10-12-years	90.8606 score on a scale Interval 87.192 to 94.5293	91.0493 score on a scale Interval 85.7998 to 96.2987	97.3806 score on a scale Interval 95.8193 to 98.9419
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Pain 15-years	90.7051 score on a scale Interval 86.6543 to 94.7559	93.5185 score on a scale Interval 89.9347 to 97.1023	98.1481 score on a scale Interval 96.6234 to 99.6729

SECONDARY outcome

Timeframe: 15 years

Population: Some subjects omitted responses from questions pertaining to the ADL score. These subjects were omitted from the overall N for score calculations. Loss to follow-up between time-points accounts for the remaining population differences. Control subjects were not assessed at 6 months.

The five dimensions of Knee Osteoarthritis Outcome Score were scored separately: pain , symptoms ,activities of daily life function, sport and recreation function, and knee-related quality of life . Each sub score has a 0-100 scale. 0- extreme knee problems and 100- no knee problems.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Activities of Daily Life Baseline	85.7680 score on a scale Interval 81.4825 to 90.0534	84.3365 score on a scale Interval 80.3405 to 88.3326	99.9755 score on a scale Interval 99.9265 to 100.0245
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Activities of Daily Life 6 months	94.8097 score on a scale Interval 92.8513 to 96.7681	90.5462 score on a scale Interval 84.5811 to 96.5114	—
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Activities of Daily Life 1-year	94.5440 score on a scale Interval 91.638 to 97.45	95.0415 score on a scale Interval 92.5158 to 97.5672	99.5037 score on a scale Interval 99.1101 to 99.9513
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Activities of Daily Life 3-years	94.5151 score on a scale Interval 91.424 to 97.6062	95.8478 score on a scale Interval 93.4576 to 98.2379	98.6779 score on a scale Interval 97.3206 to 100.0352
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Activities of Daily Life 7-years	94.8938 score on a scale Interval 91.7594 to 98.0282	96.5686 score on a scale Interval 93.5857 to 99.5515	98.6592 score on a scale Interval 97.7352 to 99.5832
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Activities of Daily Life 10-12-years	95.7313 score on a scale Interval 93.0805 to 98.3821	94.2263 score on a scale Interval 89.7832 to 98.6694	99.4094 score on a scale Interval 98.9962 to 99.8226
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Activities of Daily Life 15-years	94.4005 score on a scale Interval 90.7854 to 98.0155	97.6190 score on a scale Interval 95.4553 to 99.7827	99.0686 score on a scale Interval 98.2595 to 99.8778

SECONDARY outcome

Timeframe: 15 years

Population: Some subjects omitted responses from questions pertaining to the sport score. These subjects were omitted from the overall N for score calculations. Loss to follow-up between time-points accounts for the remaining population differences. Control subjects were not assessed at 6 months.

The five dimensions of Knee Osteoarthritis Outcome Score were scored separately: pain , symptoms ,activities of daily life function, sport and recreation function, and knee-related quality of life . Each sub score has a 0-100 scale. 0- extreme knee problems and 100- no knee problems.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Sport 15-years	80.5769 score on a scale Interval 71.9835 to 89.1703	87.3810 score on a scale Interval 81.9653 to 92.7966	95.0000 score on a scale Interval 91.2021 to 98.7979
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Sport Baseline	54.7866 score on a scale Interval 47.7469 to 61.8263	54.8882 score on a scale Interval 47.9207 to 61.8557	98.0720 score on a scale Interval 96.909 to 99.2351
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Sport 6 months	75.7059 score on a scale Interval 69.6028 to 81.809	73.9286 score on a scale Interval 67.9167 to 79.9404	—
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Sport 1-year	79.5708 score on a scale Interval 74.416 to 84.726	80.3846 score on a scale Interval 74.33 to 86.4392	95.9575 score on a scale Interval 93.5311 to 98.3838
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Sport 3-years	81.6216 score on a scale Interval 76.0324 to 87.2108	83.2353 score on a scale Interval 77.2962 to 89.1744	92.6923 score on a scale Interval 87.0987 to 98.2859
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Sport 7-years	80.0000 score on a scale Interval 73.6754 to 86.3246	87.7778 score on a scale Interval 82.1937 to 93.3618	93.6765 score on a scale Interval 90.187 to 97.1659
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Sport 10-12-years	85.0000 score on a scale Interval 79.8987 to 90.1013	85.7407 score on a scale Interval 78.9669 to 92.5146	94.0000 score on a scale Interval 90.791 to 97.209

SECONDARY outcome

Timeframe: 15 years

Population: Some subjects omitted responses from questions pertaining to the QOL score. These subjects were omitted from the overall N for score calculations. Loss to follow-up between time-points accounts for the remaining population differences. Control subjects were not assessed at 6 months.

The five dimensions of Knee Osteoarthritis Outcome Score were scored separately: pain , symptoms ,activities of daily life function, sport and recreation function, and knee-related quality of life . Each sub score has a 0-100 scale. 0- extreme knee problems and 100- no knee problems.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Quality of Life Baseline	35.6944 score on a scale Interval 30.6595 to 40.7294	37.9360 score on a scale Interval 31.5675 to 44.3046	97.3517 score on a scale Interval 95.4119 to 99.2915
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Quality of Life 6 months	61.2132 score on a scale Interval 54.86 to 67.5665	58.1250 score on a scale Interval 52.239 to 64.011	—
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Quality of Life 1-year	74.0612 score on a scale Interval 68.719 to 79.404	67.6282 score on a scale Interval 60.4756 to 74.7808	95.4122 score on a scale Interval 92.1426 to 98.6819
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Quality of Life 3-years	78.8851 score on a scale Interval 71.6463 to 86.1239	77.7674 score on a scale Interval 71.2467 to 84.268	93.2692 score on a scale Interval 88.3153 to 98.2231
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Quality of Life 7-years	75.6944 score on a scale Interval 68.8883 to 82.5006	81.2500 score on a scale Interval 73.6973 to 88.8027	92.4632 score on a scale Interval 87.5754 to 97.3511
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Quality of Life 10-12-years	85.2823 score on a scale Interval 79.8469 to 90.7176	77.7778 score on a scale Interval 68.4543 to 87.1013	94.2857 score on a scale Interval 90.7215 to 97.8499
Knee Injury and Osteoarthritis Outcome Score (KOOS) - Quality of Life 15-years	81.9712 score on a scale Interval 75.1476 to 88.7947	75.5952 score on a scale Interval 64.398 to 86.7924	94.7917 score on a scale Interval 91.0095 to 98.5739

SECONDARY outcome

Timeframe: 15 years

Population: Loss to follow-up or questionnaire-only participant

Difference in Anterior-Posterior (A-P) knee laxity value; A-P laxity is defined as the amount of A-P directed translation of the tibia (relative to the femur) between the shear load limits of -90 N (posterior) and 133 N (anterior).

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Knee Joint Laxity Baseline	4.5107 Millimeters Interval 3.8889 to 5.1324	4.1532 Millimeters Interval 3.3972 to 4.9091	0.4383 Millimeters Interval 0.1187 to 0.758
Knee Joint Laxity 6-months	1.6605 Millimeters Interval 0.8297 to 2.4914	0.8389 Millimeters Interval -0.1027 to 1.7805	—
Knee Joint Laxity 1-year	2.3026 Millimeters Interval 1.4965 to 3.1086	2.1378 Millimeters Interval 1.1908 to 3.0848	0.1417 Millimeters Interval -0.2299 to 0.5133
Knee Joint Laxity 3-years	1.7727 Millimeters Interval 1.0241 to 2.5213	2.4545 Millimeters Interval 1.5927 to 3.3164	-0.8919 Millimeters Interval -1.4717 to -0.3121
Knee Joint Laxity 7-years	1.3436 Millimeters Interval -0.2096 to 2.8969	1.3890 Millimeters Interval 0.2023 to 2.5756	-0.3301 Millimeters Interval -1.2242 to 0.5641
Knee Joint Laxity 10-12-years	1.0763 Millimeters Interval -0.3137 to 2.4662	1.7086 Millimeters Interval -0.2736 to 3.6909	-0.0328 Millimeters Interval -0.9127 to 0.847
Knee Joint Laxity 15-years	.9907 Millimeters Interval 0.3171 to 1.6644	1.5967 Millimeters Interval -0.827 to 4.0204	1.1002 Millimeters Interval -0.4689 to 1.5917

SECONDARY outcome

Timeframe: 15 years

Population: Loss to follow-up or questionnaire-only subject

Clinical outcome was assessed using the 2000 IKDC Knee Examination Score (http://www.sportsmed.org). The IKDC scores evaluate 4 categories: function, symptoms, range of knee motion, and clinical examination.The IKDC score rates knees as normal (A), nearly normal (B), abnormal (C), and severely abnormal (D), with the final IKDC rating based on the score of the worst category.

Outcome measures

Outcome measures
Measure	Low-tension n=46 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the Low-tension group will receive the low-tension treatment with initial graft tension set so that the anterior-posterior (A-P) displacement of the reconstructed knee is equal to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	High-tension n=44 Participants Patients recruited to study the initial graft tension during ACL reconstruction surgery who were randomized to the High-tension group will receive the high-tension treatment with the initial graft tension set to reduce A-P displacement by 2 millimeters relative to that of the uninjured knee. Initial graft tension during ACL reconstruction surgery: The amount of tension that is applied to the graft at the time of fixation is being performed with the knee in two different positions. When the knee is at 30 degrees of flexion, the resulting laxity is approximately 2 mm less than the contralateral leg (the "High Tension" treatment). When the tension is performed with the knee in extension (0 degrees of flexion), the the laxity is equal to that of the contralateral leg (the "Low Tension" treatment). Both methods are commonly used in clinical practice. The effect it may have on articular cartilage remains unknown.	Uninjured Control Group n=60 Participants Uninjured age, sex, and race matched control group
Limb Strength International Knee Documentation Committee (IKDC) Score Baseline · B	27 Participants	28 Participants	2 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 1-year · B	11 Participants	16 Participants	2 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 15-years · C	3 Participants	2 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 15-years · D	1 Participants	0 Participants	1 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score Baseline · A	0 Participants	0 Participants	58 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score Baseline · C	17 Participants	13 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score Baseline · D	1 Participants	2 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 6-months · A	21 Participants	21 Participants	—
Limb Strength International Knee Documentation Committee (IKDC) Score 6-months · B	16 Participants	15 Participants	—
Limb Strength International Knee Documentation Committee (IKDC) Score 6-months · C	2 Participants	1 Participants	—
Limb Strength International Knee Documentation Committee (IKDC) Score 6-months · D	0 Participants	0 Participants	—
Limb Strength International Knee Documentation Committee (IKDC) Score 1-year · A	21 Participants	16 Participants	46 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 1-year · C	5 Participants	5 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 1-year · D	0 Participants	0 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 3-years · A	17 Participants	17 Participants	30 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 3-years · B	12 Participants	11 Participants	5 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 3-years · C	4 Participants	5 Participants	2 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 3-years · D	0 Participants	0 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 7-years · A	9 Participants	7 Participants	24 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 7-years · B	16 Participants	22 Participants	8 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 7-years · C	7 Participants	0 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 7-years · D	0 Participants	0 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 10-12-years · A	6 Participants	8 Participants	22 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 10-12-years · B	19 Participants	9 Participants	4 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 10-12-years · C	1 Participants	3 Participants	0 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 10-12-years · D	0 Participants	2 Participants	1 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 15-years · A	8 Participants	5 Participants	14 Participants
Limb Strength International Knee Documentation Committee (IKDC) Score 15-years · B	6 Participants	6 Participants	5 Participants

SECONDARY outcome

Timeframe: 15 years

Population: Some subjects omitted responses from questions pertaining to the physical functioning score. These subjects were omitted from the overall N for score calculations. Loss to follow-up between time-points accounts for the remaining population differences. Control subjects were not assessed at 6 months.