United States Patent
US Patent 4583555: Knee ligament testing system
US 4583555 ยท granted 1986-04-22
Abstract
A tibia-referenced system for objectively testing the integrity of the anterior and posterior cruciate ligaments of the knee with passive drawer, active drawer, and end point tests. Two simplified forms of the invention embody an elongated reference arm with a distal end pad that is fulcrumed against a distal region on the tibia and a proximal reference pad that rests on either the tibial tubricle or patellar bone structure, while a displacement indicator rod slidably mounted on the arm carries another proximal reference pad that rests on the other of these two bone structures adjacent the knee joint. In a third form of intermediate complexity, the second reference structure, instead of the indicator rod, is a second elongated reference arm distally pivotally connected to the other reference arm, each of the two arms carrying a reference pad that rests on a respective one of the tibial tubricle and pateller bone structures; and in this form the relative angular pivotal positions of the arms is translated to a displacement indicator dial that provides a direct readout of anterior or posterior drawer shift. The fourth and most complex form of the invention has the distally pivoted reference arms and direct readout displacement indicator dial of the third form, and further includes a case in which the arms are pivoted that is strapped against the tibia, with a force-applying handle extending anteriorly of the case and a force-indicating transducer operatively arranged between the handle and the case to audibly indicate predetermined applied force levels.
| Patent Number | 4583555 |
|---|---|
| Title | Knee ligament testing system |
| Filed | 1983-01-03 |
| Granted | 1986-04-22 |
| Inventor(s) | Daniel; Dale M., Jamison; Conny M., Landesman; Robert E., Malcom; Lawrence L. |
| Assignee | Medmetric Corporation |
| CPC Classification | A61B 5/103 |
| Number of Claims | 122 |
Abstract
A tibia-referenced system for objectively testing the integrity of the anterior and posterior cruciate ligaments of the knee with passive drawer, active drawer, and end point tests. Two simplified forms of the invention embody an elongated reference arm with a distal end pad that is fulcrumed against a distal region on the tibia and a proximal reference pad that rests on either the tibial tubricle or patellar bone structure, while a displacement indicator rod slidably mounted on the arm carries another proximal reference pad that rests on the other of these two bone structures adjacent the knee joint. In a third form of intermediate complexity, the second reference structure, instead of the indicator rod, is a second elongated reference arm distally pivotally connected to the other reference arm, each of the two arms carrying a reference pad that rests on a respective one of the tibial tubricle and pateller bone structures; and in this form the relative angular pivotal positions of the arms is translated to a displacement indicator dial that provides a direct readout of anterior or posterior drawer shift. The fourth and most complex form of the invention has the distally pivoted reference arms and direct readout displacement indicator dial of the third form, and further includes a case in which the arms are pivoted that is strapped against the tibia, with a force-applying handle extending anteriorly of the case and a force-indicating transducer operatively arranged between the handle and the case to audibly indicate predetermined applied force levels.
Claim 1
A method of testing a cruciate knee ligament which comprises the steps of: making a determination of first locations relative to each other, in the general anterior/posterior direction, of the tibial tubrical and patellar bone structures adjacent the knee joint of a leg by engaging first and second locating membersdirectly against the anterior surface of the leg in registry with the tibial tubrical and patellar bone structures, respectively, and making a first comparison of the relative positions of said locating members in the general anterior/posteriordirection; while maintaining said engagement of said locating members against said leg, applying a force to the proximal tibia of said leg in the general anterior/posterior direction, with said patellar bone structure being restrained against movement, soas to relatively displace said bone structures from their said first relative locations to second locations relative to each other in the general anterior/posterior direction which will cause a corresponding relative displacement between said locatingmembers; and while said force is being applied making a determination of said second relative locations of said bone structures by mak
Claims
122 totalA method of testing a cruciate knee ligament which comprises the steps of: making a determination of first locations relative to each other, in the general anterior/posterior direction, of the tibial tubrical and patellar bone structures adjacent the knee joint of a leg by engaging first and second locating membersdirectly against the anterior surface of the leg in registry with the tibial tubrical and patellar bone structures, respectively, and making a first comparison of the relative positions of said locating members in the general anterior/posteriordirection; while maintaining said engagement of said locating members against said leg, applying a force to the proximal tibia of said leg in the general anterior/posterior direction, with said patellar bone structure being restrained against movement, soas to relatively displace said bone structures from their said first relative locations to second locations relative to each other in the general anterior/posterior direction which will cause a corresponding relative displacement between said locatingmembers; and while said force is being applied making a determination of said second relative locations of said bone structures by mak