Injuries to the anterior cruciate ligament (ACL) are at epidemic proportions especially in those involved in athletic endeavors. However much diagnosis, treatment and rehabilitation remain an enigma because of controversy regarding ACL functions. The investigators will use a miniature transducer to measure ACL strain in vivo. The transducer is based on a Hall-effect principle and will be arthroscopically inserted into the ACL in patients undergoing arthroscopic surgery. In all patients the ACL strain will be computed as the knee is passively taken from full extension to 120 degrees of flexion. Strain will also be established under active quadriceps and hamstring contractions. These data will be used to establish the effect of muscle contractions on strain, and will provide a basis for knee rehabilitation regimens. In addition, the electromyographic activity of the hamstrings and quadriceps will be related to ACL strain. ACL strain in vivo will also be established under varus/valgus and external and internal rotation torques and under clinical knee function testing. In some subjects the effect of continuous passive motion on the strain in the ACL will be established. The ACL strain will also be measured during clinical knee testing (Lachman and drawer) and this will be compared to results obtained in a new clinical test machine, the Genucom. The effect of knee rehabilitation machine, Cybex II, in straining the ACL, will be established. The ACL strain will also be determined in various simulated activities of daily living and in sporting activities. Knee braces will be evaluated by establishing the change of ACL strain with and without the braces. These data are expected to be extremely useful to those involved in the evaluation, treatment and rehabilitation of knee injuries.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR039213-04
Application #
3159194
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1988-02-01
Project End
1992-01-31
Budget Start
1991-02-01
Budget End
1992-01-31
Support Year
4
Fiscal Year
1991
Total Cost
Indirect Cost
Name
University of Vermont & St Agric College
Department
Type
Schools of Medicine
DUNS #
066811191
City
Burlington
State
VT
Country
United States
Zip Code
05405
Fleming, Braden C (2003) Biomechanics of the anterior cruciate ligament. J Orthop Sports Phys Ther 33:A13-5
Fleming, B C; Peura, G D; Beynnon, B D (2000) Factors influencing the output of an implantable force transducer. J Biomech 33:889-93
Fleming, B C; Beynnon, B D; Renstrom, P A et al. (1999) The strain behavior of the anterior cruciate ligament during stair climbing: an in vivo study. Arthroscopy 15:185-91
Fleming, B C; Good, L; Peura, G D et al. (1999) Calibration and application of an intra-articular force transducer for the measurement of patellar tendon graft forces: an in situ evaluation. J Biomech Eng 121:393-8
Fleming, B C; Beynnon, B D; Renstrom, P A et al. (1998) The strain behavior of the anterior cruciate ligament during bicycling. An in vivo study. Am J Sports Med 26:109-18
Beynnon, B D; Fleming, B C (1998) Anterior cruciate ligament strain in-vivo: a review of previous work. J Biomech 31:519-25
Beynnon, B D; Johnson, R J; Fleming, B C et al. (1997) The effect of functional knee bracing on the anterior cruciate ligament in the weightbearing and nonweightbearing knee. Am J Sports Med 25:353-9
Beynnon, B D; Johnson, R J; Fleming, B C et al. (1997) The strain behavior of the anterior cruciate ligament during squatting and active flexion-extension. A comparison of an open and a closed kinetic chain exercise. Am J Sports Med 25:823-9
Beynnon, B; Yu, J; Huston, D et al. (1996) A sagittal plane model of the knee and cruciate ligaments with application of a sensitivity analysis. J Biomech Eng 118:227-39
Beynnon, B D; Fleming, B C; Johnson, R J et al. (1995) Anterior cruciate ligament strain behavior during rehabilitation exercises in vivo. Am J Sports Med 23:24-34

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