The long term goal of this project is to understand the biomechanical functions of the cruciate ligaments through an extensive and detailed study of the forces generated in these important structures. A series of controlled loading tests will be performed on fresh cadaveric specimens to identify the applied knee forces and moments which generate high cruciate ligament forces. Knowledge of cruciate ligament forces (and the types of knee loadings which produce them) is important in identifying and understanding mechanisms of injury, and for formulating recommendations for post-operative sports activities and rehabilitation exercises which will limit forces generated in a ligament which has undergone repair, augmentation, or substitution. The effects of graft pretension on the forces developed in an ACL substitute are important for developing protocols for optimum surgical implantation. In preliminary work, a new and unique experimental technique has been developed for the direct measurement of the resultant ACL force in cadaver specimens. This technique involves mechanical isolation of a bone plug containing the ACL's tibial insertion, and fixation of this bone plug into a specially designed miniature load cell which measures the three components of ACL force as external loads are applied to the tibia. The resultant force and its direction of pull are calculated and stored using a computerized data acquisition system. For this project, both the ACL and PCL will be instrumented and specific straight loading tests (under defined test conditions) will be performed including: passive flexion/extension, applied AP tibial force, applled internal/external tibial torque, and applied varus-valgus bending moment. Combined loading tests will consist of selected combinations of the above straight loading modes.
The specific aims of this investigation are as follows: 1. Forces in the PCL will be measured during a series of straight and combined loading tests. 2. The effect of detaching one cruciate ligament upon the force developed in the remaining cruciate ligament will be determined. 3. The relationship between localized ligament strains (as measured by implanted Hall effect transducers) and total ligament force (as recorded by the cruciate load cells) will be determined. 4. The effects of combined section of the posterolateral structures (lateral collateral ligament + popliteus tendon + arcuate complex) upon the force generated in the posterior cruciate ligament will be studied. 5. The relationship between graft pretension and the force developed in a cruciate ligament substitute will be studied.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR040330-02
Application #
3160678
Study Section
Respiratory and Applied Physiology Study Section (RAP)
Project Start
1991-07-01
Project End
1994-06-30
Budget Start
1992-07-01
Budget End
1993-06-30
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of California Los Angeles
Department
Type
Schools of Medicine
DUNS #
119132785
City
Los Angeles
State
CA
Country
United States
Zip Code
90095
Hame, Sharon L; Markolf, Keith L; Hunter, D Monte et al. (2003) Effects of notchplasty and femoral tunnel position on excursion patterns of an anterior cruciate ligament graft. Arthroscopy 19:340-5
Markolf, Keith L; Hame, Sharon L; Hunter, D Monte et al. (2002) Biomechanical effects of femoral notchplasty in anterior cruciate ligament reconstruction. Am J Sports Med 30:83-9
Markolf, Keith L; Hame, Sharon; Hunter, D Monte et al. (2002) Effects of femoral tunnel placement on knee laxity and forces in an anterior cruciate ligament graft. J Orthop Res 20:1016-24
Hame, Sharon L; Oakes, Daniel A; Markolf, Keith L (2002) Injury to the anterior cruciate ligament during alpine skiing: a biomechanical analysis of tibial torque and knee flexion angle. Am J Sports Med 30:537-40
Markolf, K L; Willems, M J; Jackson, S R et al. (1998) In situ calibration of miniature sensors implanted into the anterior cruciate ligament part I: strain measurements. J Orthop Res 16:455-63
Markolf, K L; Willems, M J; Jackson, S R et al. (1998) In situ calibration of miniature sensors implanted into the anterior cruciate ligament part II: force probe measurements. J Orthop Res 16:464-71
Markolf, K L; Slauterbeck, J R; Armstrong, K L et al. (1997) A biomechanical study of replacement of the posterior cruciate ligament with a graft. Part 1: Isometry, pre-tension of the graft, and anterior-posterior laxity. J Bone Joint Surg Am 79:375-80
Markolf, K L; Slauterbeck, J R; Armstrong, K L et al. (1997) A biomechanical study of replacement of the posterior cruciate ligament with a graft. Part II: Forces in the graft compared with forces in the intact ligament. J Bone Joint Surg Am 79:381-6
Markolf, K L; Slauterbeck, J L; Armstrong, K L et al. (1996) Effects of combined knee loadings on posterior cruciate ligament force generation. J Orthop Res 14:633-8
Markolf, K L; Burchfield, D M; Shapiro, M M et al. (1996) Biomechanical consequences of replacement of the anterior cruciate ligament with a patellar ligament allograft. Part I: insertion of the graft and anterior-posterior testing. J Bone Joint Surg Am 78:1720-7

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