Device and method for knee ligament strain measurement
OwnerHermann Mayrinventor
Life of this patent
Estimating the term…
Abstract
A device for measuring displacement of the tibia in relation to the femur in response to an applied force or torque on the tibia. A first shaft is tiltable about a first axis close to the ankle and approximately parallel to the coronal plane of the patient's body. A second shaft is connected to the first shaft and is rotatable about a second axis perpendicular to the first axis, and is close to the ankle and approximately parallel to the tibia. A foot support platform is mounted on the second shaft, the foot support platform being configured for attachment of the foot at a fixed position. A displacement test device is provided for applying forces to the tibia and measuring the shift or displacement of the proximal tibia relative to the distal femur.
Claims15
A device for measuring displacement of the tibia (46) in relation to the femur (56) in response to an applied force or torque on the tibia and/or the femur, comprising
- a first shaft (10) being tiltable about a first axis close to the ankle and approximately parallel to the coronal plane of a patient's body,
- a second shaft (20) being connected to said first shaft (10) and being rotatable about a second axis perpendicular to said first axis, being close to the ankle and approximately parallel to the tibia,
- a foot support platform (30) being mounted on said second shaft (20), the foot support platform having means for attaching the foot thereto at a fixed position.
Method for measuring displacement of the tibia (46) with respect to the femur (56) in response to an applied force on the tibia, comprising the steps of:
- a) affixing the foot (42) to a foot support platform (30), the foot platform being positioned close to a natural position of the foot,
- b) tilting the foot support platform about a first axis close to an ankle and parallel to the coronal plane of the patient's body for dorsiflexion,
- c) rotating the foot support platform (30) about a second axis perpendicular to the first axis,
- d) measuring the rotational angle at a predetermined force or torque or measuring the force or torque at a predetermined rotational angle.
Method for measuring displacement of the tibia (46) with respect to the femur (56) in response to an applied force on the tibia, comprising the steps of:
- a) affixing the foot (42) to a foot support platform (30), the foot platform being positioned close to a natural position of the foot,
- b) tilting the foot support platform about a first axis close to the ankle and parallel to the coronal plane of the patient's body for dorsiflexion,
- c) rotating the foot support platform (30) about a second axis perpendicular to the first axis,
- d) applying at least one force to the tibia in relation to the femur or the patella,
- e) measuring displacement between the tibia and the femur or the patella.
Method according to claim 13,
- wherein the tilting in step b) is performed by a predetermined force or that tilting in step b) is finished when at least one of a predetermined angle, a predetermined position, or a predetermined force has been reached.
Method according to claim 13,
- Wherein the tilting in step b) comprises the following steps:
- b1) tilting the foot towards the patient for dorsiflexion with a constant torque, at a predetermined first force, or until a predetermined first position or a predetermined first force has been reached,
- b2) tilting into the opposite position for a predetermined time or a predetermined position,
- b3) tilting towards the patient for dorsiflexion with a constant torque, at a predetermined second force or until a predetermined second position or a predetermined second force has been reached,
- b4) optionally repeating previous tilting steps b1) to b3).
Method according to claim 13,
- wherein the tilting in step c) comprises the following steps:
- c1) rotating the foot in a first a direction with a predetermined first torque, at a predetermined first force, or until a predetermined first position or a predetermined first force has been reached,
- c2) rotating in the opposite direction for a predetermined time or a predetermined position,
- c3) rotating in the first direction at a predetermined second torque, with a predetermined second force or until a predetermined second position or a predetermined second force has been reached,
- c4) optionally repeating previous tilting steps c1) to c3).
Dependencies are inferred from the claim text.