No abstract

The results provide quantitative data to guide clinical assessment of forward bending motion. Results also suggest that although people with a history of low back pain have amounts of lumbar spine and hip motion during forward bending similar to those of healthy subjects, the pattern of motion is different. It may be desirable to teach patients with a history of low back pain to use more hip motion during early forward bending, and hamstring stretching may be helpful for encouraging earlier hip motion.

In the present study, the tensile mechanical properties of all of the collateral ligaments of the human ankle joint were determined, in vitro, from tensile tests conducted on 120 ligaments obtained from 20 fresh lower limbs. The ultimate load of the lateral collateral ligaments increased in an anteroposterior sequence, with the anterior fibulotalar ligament less than the fibulocalcaneal ligament and less than the posterior fibulotalar ligament. For the medial collateral ligaments, the increasing order of ultimate load was found to be tibiocalcaneal ligament, tibionavicular ligament, tibiospring ligament, posterior tibiotalar ligament. The posterior tibiotalar ligament and tibiospring ligament, so frequently neglected in the anatomical and orthopaedic literature, demonstrated the highest yield force and ultimate load of all of the collateral ligaments of the ankle. Additionally, the tibiospring ligament showed high yield and ultimate elongation properties probably related to its distal attachment to the spring ligament. The fibulocalcaneal ligament was found to have high linear elastic modulus suggesting some type of unique material properties or internal fiber organization. Knowledge of the mechanical characteristics of the ligaments of the ankle joint contributes to an understanding of their normal function, pathomechanics of injury, and their optimal surgical reparative procedure and reconstructive material. A knowledge of the normal mechanical properties of the ankle ligaments provides a data base to evaluate which of the multiplicity of present tendon graft materials has mechanical properties similar to those of the ligaments to be replaced. Those tendon grafts will be the most suitable for replacement of specific ligaments. Finally, data on the mechanical properties of these ligaments offer the possibility for evaluating any future biological or prosthetic grafts.

The in-vitro, three dimensional kinematic characteristics of the human ankle and subtalar joint were investigated in this study. The main goals of this investigation were: 1) To determine the range of motion of the foot-shank complex and the associated range of motion of the ankle and subtalar joints; 2) To determine the kinematic coupling characteristics of the foot-shank complex, and 3) To identify the relationship between movements at the ankle and subtalar joints and the resulting motion produced between the foot and the shank. The tests were conducted on fifteen fresh amputated lower limbs and consisted of incrementally displacing the foot with respect to the shank while the motion of the articulating bones was measured through a three dimensional position data acquisition system. The kinematic analysis was based on the helical axis parameters describing the incremental displacements between any two of the three articulating bones and on a joint coordinate system used to describe the relative position between the bones. From the results of this investigation it was concluded that: 1) The range of motion of the foot-shank complex in any direction (dorsiflexion/plantarflexion, inversion/eversion and internal rotation/external rotation) is larger than that of either the ankle joint or the subtalar joint.; 2) Large kinematic coupling values are present at the foot-shank complex in inversion/eversion and in internal rotation/external rotation. However, only a slight amount of coupling was observed to occur in dorsiflexion/plantarflexion.; 3) Neither the ankle joint nor the subtalar joint are acting as ideal hinge joints with a fixed axis of rotation.; 4) Motion of the foot-shank complex in any direction is the result of rotations at both the ankle and the subtalar joints. However, the contribution of the ankle joint to dorsiflexion/plantarflexion of the foot-shank complex is larger than that of the subtalar joint and the contribution of the subtalar joint to inversion/eversion is larger than that of the ankle joint.; 5) The ankle and the subtalar joints have an approximately equal contribution to internal rotation/external rotation movements of the foot-shank complex.

Participants who were currently asymptomatic but had a history of low back pain moved in a manner similar to that of participants with no history of low back pain except that they demonstrated greater lumbar motion and velocity during the initial phase of extension. This may have been the result of low back pain or a contributing factor in recurrent low back pain.