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Contents
1. 40 45 50 55 60 65 6 indicia of arc travel representing millimeters of reference pad travel However the novelty of the present improvement lies in the modification of the indicator to be a maximum read indicator In other words once it is zero adjusted the analog indicator of the present improvement moves only in the direction indicative of pad travel and does not reverse its movement when the pads return to their original positions The indicator of the present invention functions the same way that a medical thermometer functions by reaching a maximum reading and remaining in that condition until reset The advantage gained by a maximum read pad travel distance indicator is that the examining doctor no longer has to apply concentrated vigilance in observing the distance travel indicator it will now with the present invention automatically maximum read The examining doctor will be free to observe the patient and the conditions of the exami nation without undue or special focus on observing the prior art KT 1000 which very briefly displays numerical value of an indicator While the preferred embodiment of the present invention employs the above described maximum read analog dis tance indicator a non preferred embodiment of the present invention provides for a digital display of distance traveled As to solving the problem of the prior art KT 1000 force indicator having an audible horn the preferred em2. manufactured and sold by MEDmetric Corporation 4901 Morena Boulevard Suite 322 San Diego Calif 92117 and protected by U S Pat No 4 583 555 The KNEE LIGAMENT ARTHROMETER in common use is known as the Model KT 1000 The KT 1000 is the prior art upon which the present invention is an improvement on both the apparatus and the method of use The MEDmetric Corporation teaches that its KT 1000 is to be used for measuring and assessing the integrity of only the ligaments in the knee of a patient being examined MED metric teaches away from the present invention in that the present invention embodies a method of use of the KT 1000 for ankle laxity measurement and is thus specifically disapproved taught away from by MEDmetric While MEDmetric teaches use of its KT 1000 only for the knee the present invention teaches use of the KT 1000 with appropriate novel modifications as herein presented and described for use in measuring the laxity in the ankle joint The ankle joint like the knee joint is a point of frequent injury and in particular sprained and twisted ankles and ankles with more serious ligament injuries need diagnosis as often if not more often than injured knee joints Thus the novel method of use of the modified KT 1000 represents not only novel apparatus modification to the KT 1000 not only a novel method of using the modified KT 1000 but also a greatly expanded use for the modified KT 1000
3. amount of lateral force applied to the refer ence pads comprises a plurality of lights sequentially illu minated in response to discrete incremental changes in force applied to the reference pads wherein further each light sequentially illuminated represents 3 pounds of force applied to the reference pads 11 The device of claim 8 further wherein the means for indicating the amount of force applied to the reference pads comprises a plurality of indicator lights sequentially illumi nated in response to discrete incremental changes in force applied to the reference pads wherein further the plurality of indicator lights is comprised of varying colors with the illumination of each respective color and or each respective combination of colors providing a coded indication of the amount of force 12 The device of claim 8 further wherein the means for indicating the amount of force applied to the reference pads comprises a maximum reading digital indicator requiring manual resetting and further wherein the indicia of relative distance traveled by the reference pads comprises digital indicia 13 A method of measuring the ankle joint laxity in a patient being medically examined comprising the steps of a affixing the device of claim 1 to the anatomy of the patient s foot ankle and leg on the right or left side of the patient s body as required by the medical exami nation b applying the reference pad comprising the receptacle t
4. horn of the prior art KT 1000 In addition comparison trials were made using maximum manual force in place of the prior art KT 1000 The foregoing test procedure was then repeated after transecting the anterior talofibular ligament ATFL and again after transecting the calcaneofibular ligament CFL After all data on relative translational distance movement i e a measurement of ankle joint laxity were acquired and recorded for each ankle a complete dissection of the joint was performed in order to examine the specimen for any conditions such as arthritis which might have caused data to be rejected The results of the aforedescribed trials were as follows It was found that relative displacement of the ankle joint increased upon each subsequent ligament transection Neutral lt ATFL Cut lt ATFL amp CFL Cut It was also found that trial using manual maximum force testing produced greater displacements than standardized 20 pound force as indicated by the audible indicator horn of the prior art KT 1000 It was further found that testing with the ankle at 30 plantarflexion produced greater displacements than testing with the ankle at the neutral position 0 After adjustment for all other factors no effect on ankle joint displacement was attributable to the observer F 0 80 p 0 45 After adjustment for all other factors the ankle joint displacement within each subject did not differ signifi cantly between trials A
5. in that ankle injuries as a new category of injury will be added to the utility of the newly modified KT 10007M 10 15 20 25 30 40 45 50 55 60 65 2 In so doing the present invention addresses a long felt need in the art of orthopedic diagnosis of ankle joint injury namely to standardize and to make quick convenient and most important reliable the assessment and diagnosis of injury to the ankle joint This is especially important in view of the large number of ankle joint sports injuries which are currently being treated The type of injury for which MEDmetric teaches that its KT 1000 is useful is in diagnosis of injury to the knee in which the cruciate ligament s is are injured by tearing hyperextending or otherwise Cruciate ligaments are struc tures which are specific to the knee Injury to the cruciate ligaments often manifests itself in the laxity of the cruciate ligaments which laxity in turn results in the tibial bone having more relative translational movement ability than would be available to the tibial bone in a normal healthy knee Because the tibial bone is able to wobble in a knee where the cruciate ligaments are compromised a knee with injury to the cruciate ligaments may be termed unstable by an orthopedic surgeon The person afflicted with this kind of cruciate ligament injury is not going to be able to rely on the firm placement of the tibial bone The injured person m
6. is exerted In a non preferred embodiment of the present invention the magnitude of force applied may be indicated by indicator lights of different colors singly illuminated or in combina tions For example a blue indicator light could indicate 3 pounds of applied force a green light could indicate 6 pounds and so forth Alternatively and also non preferred is an embodiment of the present invention in which printed indicia upon the improved device of the present invention may indicate a given force level as where for example a plurality of indicator lights have imprinted adjacent to them respectively 3 pounds 6 pounds 9 pounds and so forth so 5 957 869 7 that when a respective indicator lamp is illuminated the indication is the number of pounds of force imprinted adjacent to the illuminated lamp In yet another non preferred embodiment of the present invention applied force may be displayed digitally Such a digital display of distance traveled in relation to force applied is very common and well known in such fields of art as weight measurement in both commercial and laboratory settings Having solved the problems of the prior art KT 1000 for the knee joint measurement for which it was designed it is a further aspect of novelty of the present invention to provide a method of using the prior art KT 1000 in a way for which it was not designed and for which its manufacturer teaches that it is non useful namely
7. of different ligaments In this novel method using the prior art KT 1000 the present invention has solved the recognized problem in orthopedic diagnosis of how to reliably accurately reproducibly conveniently and comfortably measure the laxity of an injured ankle joint A further apparatus improvement made by the present invention over and above the prior art apparatus of the KT 1000 is an anatomical reference pad which comprises a receptacle The prior art KT 1000 has two reference pads as noted above a patella reference pad and a tibial reference pad Both of these pads in the prior art KT 1000 are substan tially flat and tabular They are placed in contact with the 5 957 869 9 patient but they do not conform to the contours of the patient s anatomy at the point where they contact the skin To provide a better contour fit as an improvement and to make ankle joint laxity measurement yet more reliable a patient heel receptacle has been added As a novel improvement over the prior art KT 1000 the present invention provides a molded form fitting heel receptacle which comprises one of the reference pads specifically the calcaneous reference pad for application to the patient s heel when ankle joint laxity is being measured In the preferred embodiment of the present improved KT 1000 invention the heel receptacle calcaneous reference pad is conveniently removable thus comprising an adapter for the dev
8. table of the overall results is as follows NORMAL ATFL ATFL amp CFL RESULTS UNCUT TRANSECTED TRANSECTED TABLE mm distance mm distance mm distance 20 LB FORCE 3 79 97 7 63 2 20 9 14 2 38 Neutral Angle 20 LB FORCE 3 51 1 04 7 31 2 91 9 03 2 87 30 Angle 5 957 869 11 continued NORMAL ATFL ATFL amp CFL RESULIS UNCUT TRANSECTED TRANSECTED TABLE mm distance mm distance mm distance MANUAL 5 68 4 1 11 9 82 4 2 33 11 73 1 91 MAXIMUM Neutral Angle MANUAL 6 47 1 41 11 80 4 3 15 14 61 4 2 50 MAXIMUM 30 Angle OVERALL 4 86 1 69 9 14 3 22 11 13 4 3 34 An analysis of the foregoing results of the use of the prior art KT 1000 for ankle joint laxity measurement demon strate that the novel method of the present invention using the prior art KT 1000 alone without the novel apparatus improvements of the present invention can reliably and reproducibly distinguish between varying ankle ligament conditions independent of ankle position and amount of force administered In addition the prior art KT 1000 when used with the novel method of use of the present invention and used alone without the novel apparatus improvements of the present invention can reliably and reproducibly distinguish between varying ankle ligament conditions independent of the person performing the test thus providing a low degree of intra observer variability From the results tabl
9. to describe and to claim a method of using the improved KT 1000 to measure the laxity not of the knee joint but of the ankle joint Using the improved KT 1000 for ankle joint laxity measurement may be accomplished as follows the anatomi cal reference pad which the KT 1000 manufacturer calls the patella pad will be used to contact the heel of the patient being examined Within the heel is the calcaneous bone and thus the reference pad in the improvement of the present invention is called the calcaneous pad when the improved device is used for ankle joint diagnosis When the patella pad is used as a calcaneous reference pad for ankle measurement the improved KT 1000 must be oriented upon the leg of the patient being examined in a manner different from its use in the prior art In the first place the use of the KT 1000 for the knee requires that the device be oriented so that the patella reference pad is located proximally or nearest to the body of the patient However when the improved KT 1000 is used for ankle joint measurement the patella pad now called the calcaneous pad in use for ankle joint measurement is oriented 180 opposite to its orientation for knee joint measurement This means that the patella pad now called the calcaneous reference pad is located distally or furthest from the body of the patient Simply put in order to use the improved KT 1000 to measure ankle joint laxity it is necessary to tur
10. 3 511 512 763 780 4 323 080 4 1982 Melhart et al 128 782 measuring ankle joint laxity is provided using the improved 4 583 554 4 1986 Mittelman et al 128 782 KT 1000 device of the present invention 4 583 555 4 1986 Makom et al 128 782 4 869 265 9 1989 McEwen 128 774 4 969 471 11 1990 Daniel et al sees 128 782 31 Claims 9 Drawing Sheets ME RT Sow Moa T y 5 A ee uvis 5 957 869 Sheet 1 of 9 Sep 28 1999 U S Patent gl LYV MdOltHd L Bld U S Patent 5 957 869 ry l E Fig 2 U S Patent Sep 28 1999 Sheet 3 of 9 5 957 869 22 24 23 23 U S Patent Sep 28 1999 Sheet 4 of 9 5 957 869 5 957 869 Sheet 5 of 9 Sep 28 1999 U S Patent U S Patent Sep 28 1999 Sheet 6 of 9 5 957 869 2 1i NT Ll Y z 10 Fig U S Patent Sep 28 1999 Sheet 7 of 9 5 957 869 U S Patent 5 957 869 f N Ta 3 R 5 957 869 Sheet 9 of 9 Sep 28 1999 U S Patent EL Blg 5 957 869 1 APPARATUS AND METHOD FOR MEASURING ANATOMICAL ORTHOPEDIC JOINT LAXITY BACKGROUND OF THE INVENTION Ankle sprains are the most common injury in sports the lateral ligament complex of the ankle is most often injured and approximately one quarter of all reported sports injuries occur in the foot among which about one half are sprains In addition ankle sprains ac
11. US005957869A United States Patent 5 11 Patent Number 5 957 869 Caruso et al 4 Date of Patent Sep 28 1999 54 APPARATUS AND METHOD FOR 5 335 674 8 1994 Siegler eee 128 782 MEASURING ANATOMICAL ORTHOPEDIC 5 402 800 4 1995 Hollis 128 779 JOINT LAXITY 5 435 321 7 1995 McMillen et al 128 782 5 471 996 12 1995 Boatright et al oe 128 774 76 Inventors Steven A Caruso 53 Cranford St OTHER PUBLICATIONS Staten Island N Y 10308 Steven C Sheskier 235 Warren St Brooklyn Wrist and Shoulder Motion Analyzer Research Disclo N Y 11201 sure Nov 1981 Little et al pp 404 405 Primary Examiner Max Hindenburg 21 Appl No 08 517 166 22 Filed Aug 21 1995 57 ABSLRACI BIN ARON arten A61B 5 00 improved apparatus and method are provided Tor force 52 US CI 600 592 600 595 and distance indication readings on the prior art MEDmet Ee Fi Id f S et h Er dk ee 128 774 779 rics KT 1000 which eliminate the need for an observer to ield of Search 5 R vigilantly scrutinize the analog distance indicator and which indicate the force used to produce a given distance of travel R with both the force and distance having maximum read 56 References Cited indicators In addition a removable receptacle is provided U S PATENT DOCUMENTS for adapting the prior art KT 1000 for use in measuring ankle joint laxity A method of reliably and accurately 128 782 3
12. amping walls to adjustably pivot in relation to the receptacle 6 The device of claim 5 wherein further the concave shape of the receptacle is comprised of a plurality of facets and further where the receptacle further comprises a foot stop plate for use in applying to the device to the foot of a patient adjacent to the calcaneous bone when the device is used to measure the laxity of a patient s ankle joint 7 The device of claim 6 wherein the receptacle comprises a discrete user removable and user installable adapter hav ing means for convenient and suitable application to and removal from the reference pads 8 The device of claim 7 further wherein the receptacle comprises a concave shape further comprising five facets for contacting the anatomy of the patient being examined and wherein further the means for convenient and suitable application to and removal from the reference pads comprises a channel disposed on the receptacle for slidable friction fitting on the reference pads 9 The device of claim 8 further wherein the means for indicating the amount of relative force applied to the refer ence pads comprises a plurality of lights sequentially illu minated in response to discrete incremental changes in force applied to the reference pads wherein further each light sequentially illuminated represents 5 pounds of force applied to the reference pads 10 The device of claim 8 further wherein the means for indicating the
13. at the ligaments of the ankle fail under the stress of an injury such as an ankle sprain The least serious ankle injury involves compromise only to the first anterior talar fibula ligament Progressing injuries of increasing severity will compromise the calcaneofibular ligament second and finally the posterior talofibular ligament will be compro mised in the most severe ankle sprain With any or all of the foregoing ankle ligaments compromised the ankle joint will be permitted forward or anterior movement The more lax the ligaments the greater the anterior movement will be noted by the examining doctor It is reliability reproducibility comfort and conve nience to ankle joint laxity measurement that the method of the present invention provides Because of the configuration of the fibula and the calca neous bones forward or anterior motion of the ankle joint will depend upon the joint being adjusted so that the foot is 5 957 869 3 slightly bent down Orthopedically this condition is known as joint flexion When the foot bends downward from a neutral position the flexion is called plantar flexion Thus with an optimal degree of plantar flexion experimentally found to be about 10 from the neutral position ankle joint laxity can be reliably and accurately measured according to the present invention The usefulness of a machine as compared to an exami nation performed by a doctor orthopedist or surgeon using the hands al
14. ay thus experience a tibial wobble characterized by an inadvertent unwanted and uncontrolled mis alignment of the tibial bone in relation to the knee while the knee and leg are under stress as during a standing walking or sports playing activity The misalignment result ing from the wobble predisposes the person with the injured knee to further injury and or re injury The KT 1000 is an instrument specifically designed for use by an orthopedic doctor to measure the degree to which knee ligaments are lax thus permitting at least the possibil ity of a potentially dangerous tibial wobble If the knee ligaments are more lax than they should be the tibia will have the ability to travel anteriorly or posteriorly when an examining doctor applies force in the respective anterior or posterior direction to the calf of the patient since the tibial bone is in the calf If the tibia is permitted to travel more than a healthy distance in an anterior or a posterior direction knee ligament laxity and thus knee injury is indicated by the fact of the anterior or posterior movement Diagnostic measurement of ankle joint laxity is an impor tant part of the novelty of the method of use of the present invention In the ankle joint injury to and laxity of the following ligaments in the following order is involved 1 the anterior talofibular ligament 2 the calcaneofibular ligament and 3 the posterior talofibular ligament It is in that order th
15. bodiment of the present invention employs a plurality of indicator lights The indicator lights may be any suitable design or type such as LEDs and may be of a single color or a variety of colors where color coded force magnitude indication is desired In the preferred embodiment of the present invention force is indicated by the sequential illumination of a series of indicator lights in such a manner that each illuminated indicator light represents a given number of pounds of force For example each indicator light could represent 3 pounds of force so that when 4 such lights are illuminated 12 pounds of force are indicated As with the maximum read analog distance indicator the indicator lamps showing applied force are also maximum read indicators and will remain illuminated until the force indicator is reset Current for indicator lamp illumination will be provided by a suit able battery It is also possible to provide for a series of indicator lights which illuminate sequentially to indicate a narrow range of increasing force values as for example a series of indicator lights which do not light up until say 15 pounds of force is exerted But when 15 pounds of force is reached the indicator light illuinate sequentially as each 1 pound incre ment of force is applied Thus between the application of 15 pounds and 20 pounds of force there might be six indicator lights each illuminating when a successive individual pound of force
16. ce pads by the specific anatomical structure to which they are applied because when the modified KT 1000 is used in the present invention the ankle and not the knee is measured for laxity and the anatomical structures are different in the ankle than in the knee Therefore the present invention calls the sensor pads anatomical reference pads In the present invention as well as in the prior art KT 1000 the sensor pads are capable of moving laterally in relationship to each other The prior art KT 1000 measures relative translational movement of the tibia in the anterior and or in the posterior direction The more movement the greater the degree of laxity of the knee joint and thus the greater the severity of the injury being diagnosed Such relative translational movement is produced in the prior art KT 1000 when the examining doctor applies differential force to the patient s tibia by exerting a pulling force in an anterior direction or a pushing force in the posterior direction on the handle provided for that purpose in the prior art KT 1000 The patient s tibia if it can move anteriorly will cause anterior directional movement in the tibial sensor pad of the KT undergo posterior translational movement Thus the tibial sensor pad will experience relative ante rior movement or relative posterior movement of a certain number of millimeters relative to the patella sensor pad The greater the anterior or posterior distance
17. ce traveled by one pad relative to the other further comprises a maximum reading indicator so as to indicate increasing relative distance traveled by the reference pads without resetting itself the indicator requiring manual resetting for additional uses so as to relieve the user from the necessity of constant observation of the distance indi cator and further where c the receptacle comprises a substantially concave shape 3 The device of claim 2 further wherein the means for indicating the amount of relative force applied to the reference pads comprises a plurality of indicator lights sequentially illuminated in response to discrete incremental changes in force applied to the reference pads and further the receptacle is provided with a pair of laterally adjust able clamping walls for grasping the anatomy of the patient to be examined the clamping walls further being provided with means to comfortably and conveniently adjust the device in a clamped position on the anatomy of the patient 6 rh 5 957 869 15 4 The device of claim 3 further wherein the receptacle clamping means further comprise threaded locking walls and further wherein the receptacle comprises a suitable comfortable non slippery material for grasping and clamping upon the anatomy of the patient being examined 5 The device of claim 4 wherein the receptacle further comprises hinged attachment of the clamping walls to the receptacle permitting the cl
18. count for 10 to 15 of all time lost to injuries in football on the professional college and high school levels with the average player losing five weeks Ankle ligament injury is also the most common injury in modern and classical dance Current methods of determining degree of ankle joint instability i e ankle joint laxity include a stress X Ray technique of the Talar Tilt The disadvantages include the time consumed in producing and reading an X Ray the relatively high cost the complexity and the exposure of the patient to X Radiation The manual anterior drawer test comprises a trained person orthopedic surgeon or other medical professional pulling upon the suspect ankle to note laxity in the ankle ligaments Here again the disadvantages are unreliability and variability within and between doctors and patients The present invention provides a method and an improved apparatus for quick reliable reproducible low cost and risk free ankle joint laxity measurement which is also very low in variability both intra and inter observer Reliable orthopedic joint laxity measurement is an impor tant component of orthopedic injury diagnosis particularly for knee and ankle joints and particularly because knee and ankle joints are frequently injured by people engaging in sports An orthopedic surgeon who evaluated knee injury prior to the present invention typically may have used a prior art device known as a KNEE LIGAMENT ARTHROM ETER
19. d further comprising a a pair of reference pads for contacting the anatomy of the patient whose joint laxity is to be measured the reference pads being capable of moving relative to each other in response to relative force applied by the user and wherein further b the pair of reference pads is provided with indicator means for indicating the direction of travel of the pads relative to each other and the pair of reference pads is further provided with indicator means for indicating the distance traveled by one pad relative to the other and where d the pair of reference pads is further provided with indicator means for indicating the amount of relative force applied to the pads and e the pair of reference pads being further provided with a downwardly extending receptacle for convenient and secure alignment and affixing to the heel therebelow of a patient lying in the prone position for measuring the laxity of joints and wherein both the receptacle and the patient s ankle are free from exposure to weight bear ing force other than that applied for purposes of joint laxity measurement the receptacle being adjustable by the user to secure the device in place on the patient s anatomy being mea sured 2 The device of claim 1 further wherein a the means for indicating the amount of relative force applied to the reference pads comprises visual indica tion means and b the indicator means for indicating the distan
20. e above it is shown that testing at 30 plantarflexion yielded significantly greater ankle displace ments statistically than testing at neutral 0 This is due to the fact that the ankle mortise blocks the talus from significantly moving anteriorly when the ankle is in neutral Plantarflexion during an anterior draw test allows the talus to slide under the anterior border of the ankle mortise thus producing less resistance to anterior motion It was also found that testing with the manual maximum force procedure produced statistically significant increases in ankle joint displacement when compared to testing done using the standardized 20 pound force provided by the prior art KT 1000 Eleven ankles were actually tested in the above results but one set of data was discarded due to the post testing dissection of the specimen which revealed abnormal liga ment arrangements connections A study published after the data was collected for the above described clinical experiment determined that the optimum angle for anterior draw testing is 10 plantarflex ion The goal of the above experiment was to show that the Anterior Draw Test embodied by the above described method data and results could be reliably reproduced using the prior art KT 1000 regardless of a number of variables The 30 of plantarflexion used in the above experiment was considered to be the higher end of the expected range of motion of the average ankle joint and thu
21. e is placed on and in contact with the anterior portion of the patient s calf However to use the improved KT 1000 of the present invention the device is placed on and in contact with the posterior portion of the patient s calf The prior art KT 1000 as well as the improved KT 1000 of the present invention is conveniently and suitably affixed in position by means of hook and loop straps With the improved KT 1000 affixed in position for ankle joint measurement the calcaneous reference pad is in contact with the heel of the patient and the other reference pad is in contact with the posterior calf of the patient adjacent to the Achilles tendon While this area of the patient s anatomy is somewhat soft and might otherwise be considered subject to allow relative movement due to the absence of a firm anatomical reference structure it has been found in practice with the method of using the improved KT 1000 of the present invention that indeed it is not only possible to obtain reliable ankle joint laxity measurements but that such measurements are easy and convenient as well With the improved KT 1000 of the present invention in place on the patient the examining doctor measures the laxity of the ankle joint by applying force in an anterior or in a posterior direction As with the knee the laxity of the joint in a posterior movement indicates the laxity of certain ligaments while anterior laxity indicates the compromise
22. eference pads manual reset push button 51 allows the user to reset indicator 50 after each reading FIG 8 also shows a manu ally re settable plurality of indicator lamps 70 for sequential incremental illumination to display the amount of user force applied Manual reset push button 71 permits the user to re set incremental indicator lamps 70 after each reading Lamps 70 may be provided in different colors so that only one lamp of a given color is illuminated to indicate force applied For example a green lamp might indicate 3 pounds of force a white lamp 6 pounds of force and a red lamp for example might indicate 20 pounds of force FIG 9 shows a top view of the Prior Art KT100 having a novel manually re settable analog maximum reading indi cator 50 for displaying relative displacement of the reference pads manual reset push button 51 allows the user to reset indicator 50 after each reading FIG 9 also shows a manu ally re settable plurality of indicator lamps 80 for sequential incremental illumination to display the amount of user force applied Manual reset push button 81 permits the user to re set incremental indicator lamps 80 after each reading Indicator lamps 80 are provided with indicia 82 adjacent to each respective lamp to indicate total user force applied The plurality of lamps may illuminate up to and including the user force applied or alternatively only one lamp 80 may be illuminated to indicate by virtue of the adjace
23. ent FIG 13 shows a side elevation of the calcaneous recep tacle of the present invention having a foot stop plate attached DETAILED DESCRIPTION OF THE DRAWINGS Further modifications may be made to the present inven tion without departing from its scope as noted in the appended claims FIG 1 shows the prior art KT 1000 having a patella sensor pad 10 a tibial sensor pad 12 an analog distance or displacement indicator dial 18 and a force transmitting handle 16 FIG 2 shows a persepctive view of the prior art KT 1000 with the novel improved calcaneous reference pad heel receptacle adapter 22 in place on the heel FIG 3 shows and end view of calcaneous reference pad heel receptacle adapter 22 having attachment channels 23 with friction spring clips 24 for easy and convenient slidable installation and removal from standard planar reference pad 10 provided in the prior art KT 10007 Non slippery material 26 for contacting the heel of a patient surrounds substantially concave receptacle area 27 5 957 869 13 FIG 4 shows a perspective view of the heel receptacle adapter 22 shown in FIG 3 having attachment channels 23 for slidable mounting of receptacle 22 onto calcaneous reference pad 10 of the prior art KT1000 Concave recep tacle area 27 is surrounded by non slippery material 26 for gripping the heel of a patient whose ankle joint laxity is being measured Concave receptacle area 27 is comprised of planar facets 28 o
24. f which there may be five as shown FIG 5 shows an end view modification of calcaneous reference pad heel receptacle adapter 22 having clamping wing walls 32 for grasping the heel of the patient FIG 6 shows a perspective detail of receptacle 22 as in FIG 5 having hingedly attached clamping wing walls 32 for adjusting to the size of the heel of a patient whose ankle joint laxity is being measured Threaded posts 40 comprise hinge pins for wing walls 32 Wing nuts 42 are provided for clamping the wing walls 32 in a clamped position upon the patient Threaded posts 40 are shown extending beyond the confines of receptacle 22 so as to accept wing nuts 42 thereon FIG 7 Shows a top view of the Prior Art KT1000 having novel analog manually re settable maximum reading indicator 50 for displaying relative displacement of the reference pads manual reset push button 51 allows the user to reset indicator 50 after each reading Novel digital manu ally re settable maximum reading indicator 60 is shown for displaying force applied by the user manual reset push button 61 allows resetting of the force indicator after each reading Indicators 50 and 60 are in the same general location on the prior art KT1000 as was occupied by the prior art displacement dial 18 as shown in FIG 1 FIG 8 shows a top view of the Prior Art KT100 having a novel manually re settable analog maximum reading indi cator 50 for displaying relative displacement of the r
25. he steps using the device of claim 9 18 The method of claim 17 further comprising perfor mance of the steps using the device of claim 10 19 The method of claim 18 further comprising perfor mance of the steps using the device of claim 11 20 The method of claim 19 further comprising perfor mance of the steps using the device of claim 12 21 An improved KT 1000 device for measuring the anatomical joint laxity of a patient undergoing medical examination comprising in combination with the KT 1000 at least one receptacle having means for convenient and secure affixing to desired anatomical structures for measuring the laxity of joints and wherein the at least one receptacle being attachable to and removable from the KT 1000 by the user and wherein further the at least one receptacle comprises means for secure and convenient attachment of the at least one receptacle to and removal of the at least one receptacle from the KT 1000 and wherein further the at least one receptacle comprises a substantially concave shape and the at least one recep tacle comprises a pair of laterally adjustable clamping walls for grasping the anatomy of the patient to be examined the clamping walls further being provided with means to comfortably and conveniently adjust the at least one receptacle in a clamped position on the anatomy of the patient 22 The device of claim 21 further wherein the receptacle clamping walls further comp
26. her comprising perfor mance of the steps using the device of claim 24 30 The method of claim 26 further comprising perfor mance of the steps using the device of claim 25 31 A method of measuring the ankle joint laxity in a patient being medically examined comprising the steps of a affixing the KT 1000 prior art device to the anatomy of the patient s foot ankle and leg b applying one KT 10007 reference pad to the patient s heel the reference pad so affixed comprising a calca neous reference pad and c applying a KT 1000 reference pad to the patient by bringing it in contact with the posterior portion of the patient s calf so that the reference pad is adjacent to and capable of pressing upon the patient s Achilles tendon the reference pad so affixed being a tibial reference pad since in position it is disposed adjacent to the patient s tibial bone and d applying force to the respective calcaneous and tibial reference pads so as to produce lateral movement therebetween e observing and recording the indication of the amount of lateral distance traveled by the respective reference pads relative to each other and observing and recording the indication of the amount of force applied to produce the relative distance traveled by the reference pads relative to each other as indicated by the KT 1000 force indicia and g repeating the foregoing steps on the patient s other foot ankle and leg for reference com
27. ice The heel receptacle adapter in place ankle joint laxity may be easily measured And with the adapter removed knee joint laxity may be easily measured The heel receptacle adapter is a substantially cube like structure having appropriate openings for accepting the foot and heel of the patient whose ankle laxity is being measured and the receptacle is further provided with an attachment channel for slidable friction fitting attachment onto the existing planar patella reference pad of the prior art KT 1000 In a non preferred embodiment the heel receptacle is provided as a built in non removable reference pad and the device is then useable only for measurement of ankle joint laxity In a further improvement the heel receptacle may be provided with a foot bottom stop member so as to provide not only a receptacle for the heel of the patient but also a flat bottom for the receptacle so as to conveniently and reliably locate the receptacle by contact with not only the patient s heel but also with the bottom of the patient s foot for the above described process of measuring ankle joint laxity To summarize the method of using the present invention to measure the ankle joint laxity in a patient being medically examined the steps of the method comprise the following a affixing the receptacle to the heel of the patient lying in the prone position on the ankle to be measured for joint laxity b applying a KT 1000 reference pad
28. lthough not statistically significant five right ankles and five left ankles were used for the clinical test All possible specimens were tested for range of motion using a goniom eter Ankles displaying acceptable ranges of motion ROMs particularly with regard to plantar flexion were tested In the test the cadaver was placed in a prone position so that the ankle and anterior tibia could be placed in a specially designed testing platform necessitated by the fact that cadavers could not assist in their own testing as would a live patient The testing platform allowed for ankle joint neutral posi tion testing and for testing the ankle with plantar flexion of 30 The cadaver specimen was kept immobile and the prior art KT 1000 was applied to the cadaver as described above in the method of use for ankle joint laxity testing The patella reference pad here used as a calcaneous pad was applied and contacted to the heel of the cadaver which is adjacent to the calcaneous bone within the heel Each specimen was tested for ankle joint laxity using the prior art KT 1000 with the above described method by two researchers taken from a pool of three researchers Each of the two researchers conducted three trials under a variety of variable conditions including plantarflexed angle of 30 and a neutral ankle flexion angle of zero degrees Force magnitude used in the prior art KT 1000 was at the 20 pound level as indicated by the audible
29. n it around 180 from its position used to measure knee joint laxity The patient must be in a prone position Furthermore the novel apparatus modification of the present invention includes a substantially cube shaped cal caneous reference pad comprising a receptacle for grasping the patient s heel With the patient s heel thus immobilized the device of the present invention is sufficiently positionally stable to produce reliable and reproducible results without wobbling in place upon the calcaneous of the patient The calcaneous pad receptacle may be comprised of a plurality of facets and the receptacle further comprises a foot stop plate for use in applying to the device to the foot of a patient adjacent to the calcaneous bone The receptacle may comprise a concave shape having internal facets of soft material such as foam rubber for comfortably grasping the heel of the patient The concave internal cavity of the receptacle preferably has five facets for contacting the heel of the patient being examined so as to form a cup like internal cavity The means for convenient and suitable application to and removal from the reference pads comprises a channel dis posed on the receptacle for slidable friction fitting on the reference pads The receptacle slides onto and off from the KT1000 patella reference pad here called the calcaneous pad 10 15 20 25 30 35 40 45 50 55 60 65 8 With the receptacle th
30. nt indica tion 82 the total number of pounds of user force applied FIG 10 shows an exploded view showing the Calcaneous reference pad 10 of the prior art KT1000 in positional relationship to attachment channels 23 of receptacle 22 and in positional relationship to use of the present invention on the heel of a patient for measuring ankle joint laxity FIG 11 shows a side elevation of the receptacle 22 of the present invention installed on the prior art KT1000 and in position for use in measuring ankle joint laxity of a patient 10 15 20 25 30 35 40 45 50 55 60 65 14 FIG 12 shows a cutaway perspective view of the calca neous receptacle 22 of the present invention installed upon the prior art KT1000 by sliding calcaneous pad 10 of the KT1000 into attachment channels 23 of receptacle 22 The cutaway view also shows non slippery material 26 in contact with the and grasping the heel of a patient FIG 13 shows a side elevation of calcaneous receptacle 22 having a foot stop plate 90 attached Foot stop plate 90 is suitably attached to receptacle 22 so as to contact the plantar surface of the patient s foot thereby conveniently and accurately positioning receptacle 22 upon the patient s heel What is claimed is 1 An improved KT 1000 device for measuring the anatomical joint laxity of a patient undergoing medical examination comprising means for measuring relative movement in anatomical joints an
31. o the patient s heel the receptacle so affixed being a calcaneous receptacle and 10 15 20 25 30 35 40 45 50 55 60 65 16 c applying the other reference pad by bringing it in contact with the posterior portion of the patient s calf so that the reference pad is adjacent to and capable of pressing upon the patient s Achilles tendon the refer ence pad so affixed being a tibial reference pad since in position it is disposed adjacent to the patient s tibial bone and d applying force to the reference pads so as to produce lateral movement therebetween e observing and recording the indication of the amount of lateral distance traveled by the reference pads in rela tion to each other and observing and recording the indication of the amount of force applied to the reference pads as indicated by the force indicia and g repeating the foregoing steps on the patient s other foot ankle and leg for reference comparison and h repeating the foregoing sequence to observe and record inherent intra patient variability 14 The method of claim 13 further comprising perfor mance of the steps using the device of claim 3 15 The method of claim 14 further comprising perfor mance of the steps using the device of claim 7 16 The method of claim 15 further comprising perfor mance of the steps using the device of claim 8 17 The method of claim 16 further comprising perfor mance of t
32. one is that a machine is capable of giving reliable indications of both force applied and the differential displacement of the joint in the case of knee joint exami nation Thus an important part of the problem solved by the novelty of the present invention is the introduction of instrument reliability and reproducibility to the diagnosis of ankle joint injury and the measurement of ankle joint laxity While The KT 1000 machine represents an effort to standardize diagnosis of cruciate ligament knee injury and is thus advantageous over the less reliable subjectivity of non instrumented diagnosis the KT 1000 also has disad vantages To begin with the KT 1000 is designed for contact upon and measurement of the knee joint only Consequently the KT 1000 has structures for contact ing the anatomy of a patient being examined which are specifically named for the body parts which are to be contacted The KT 1000 has two tabular anatomical reference pads which MEDmetrics respectively calls the patella sensor pad and the tibial sensor pad based upon the fact that when the KT 1000 is put in use as taught by MED metric the patella sensor pad is placed in contact with the patient s knee patella and the tibial sensor pad is placed in contact with the anterior aspect of the proximal tibia in other words on the front anterior portion of the lower leg below the patient s knee It is a disadvantage to name the anatomical referen
33. parison and h repeating the foregoing sequence to observe and record inherent intra patient variability T
34. rise threaded locking means and further wherein the receptacle comprises a suitable comfortable non slippery material for grasping and clamping upon the anatomy of the patient being examined 23 The device of claim 22 wherein the at least one receptacle further comprises hinged attachment of the clamping walls to the at least one receptacle permitting the clamping walls to adjustably pivot in relation to the recep tacle 24 The device of claim 23 wherein further the concave shape of the receptacle is comprised of a plurality of facets m 5 957 869 17 and further where the receptacle further comprises a foot stop plate for use in applying to the device to the foot of a patient adjacent to the calcaneous bone when the device is used to measure the laxity of a patient s ankle joint 25 The device of claim 24 further wherein the concave shape of the receptacle comprises five facets for contacting the anatomy of the patient being examined and wherein the means for convenient and suitable application to and removal of the receptacle respectively to and from the KT 1000 comprises a channel disposed on the receptacle for slidable friction fitting on the KT 1000 26 A method of measuring the ankle joint laxity in a patient being medically examined comprising the steps of a affixing the device of claim 21 to the anatomy of the patient s foot ankle and leg b applying the at least one receptacle to the patient
35. s heel the receptacle so affixed comprising a calcaneous receptacle and 6 applying a KT 1000 reference pad to the patient by bringing it in contact with the posterior portion of the patient s calf so that the reference pad is adjacent to and capable of pressing upon the patient s Achilles tendon the reference pad so affixed being a tibial reference pad since in position it is disposed adjacent to the patient s tibial bone and applying force to the respective reference pad and the calcaneous receptacle so as to produce lateral move ment therebetween observing and recording the indication of the amount of lateral distance traveled by the reference pad and the calcaneous receptacle relative to each other and observing and recording the indication of the amount of force applied to produce the relative distance traveled by the reference pad and calcaneous receptacle relative to each other as indicated by the force indicia and g repeating the foregoing steps on the patient s other foot ankle and leg for reference comparison and repeating the foregoing sequence to observe and record inherent intra patient variability jen eo m m 10 15 20 25 30 35 18 27 The method of claim 26 further comprising perfor mance of the steps using the device of claim 22 28 The method of claim 26 further comprising perfor mance of the steps using the device of claim 23 29 The method of claim 26 furt
36. s produced a high separation of variables It is thought that at the optimum angle of 10 of plantar flexion that the above described method will produce ideal results of accuracy reliability and reproducibility BRIEF DESCRIPTION OF THE DRAWINGS The invention can best be understood in conjunction with the drawings in which FIG 1 shows the prior art KT 1000 in a schematic view with the KT 1000 in position for measuring knee joint laxity FIG 1 shows the prior art KT 1000 having a patella sensor pad a tibial sensor pad an analog distance or displacement indicator dial and a force transmitting handle 10 15 20 25 30 35 40 45 50 55 60 65 12 FIG 2 shows the prior art KT 10007 in place for measuring ankle joint laxity according to the novel method of the present invention A calcaneous reference pad is shown in position on the heel of the patient FIG 3 shows an end view of the heel receptacle adaptor comprising the calcaneous reference pad FIG 4 shows a persepective view of the heel receptacle adaptor shown in FIG 3 FIG 5 shows an end view of a heel receptacle adapter having adjustable clamping wing walls FIG 6 shows a persepctive view of the adjustable heel receptacle adapter of FIG 5 FIG 7 shows a top view of the Prior Art KT100 having a novel manually re settable analog maximum reading indi cator for displaying relative displacement of the reference pads and a manuall
37. t i e how many millimeters are traveled by the reference pads and thus by the tibia under examination When the examining doctor releases his or her anterior direction pressure upon the handle of the prior art KT 1000 the patient s knee joint immediately resumes its pre examination position Unfortunately when the patient s knee resumes its position so does the analog distance indicator on the prior art KT 1000 and if the examining doctor failed to note the very brief extent of the arc swept by the analog indicator the doctor will have to repeat the pressure test A further disadvantage of the prior art KT 1000 is the fact that the examining doctor may apply pressure in an anterior direction by pulling the handle of the KT 1000 provided for that purpose but the doctor has no way to know how much pulling pressure is being applied until a force of 15 pounds or 67 Newtons N is achieved at which time the prior art KT 1000 sounds a horn Upon further application of 20 pounds 89 N of anterior direction force a second different tone is sounded by the KT 1000 horn to alert the examining doctor to the amount of force being applied Not only is there no available measure of smooth and continuous application of anterior force against which knee joint laxity may be measured but also the sounding of the horn is likely to frighten the patient And there is no way for the examining doctor to know how far above 20 po
38. ther 3 pounds 5 pounds 10 pounds 15 or 20 pounds of anterior direction force were required to produce the 4 millimeter movement If less force were required to produce the same movement then both force and movement should be taken into account in assessing joint laxity The same movement produced by less force indicates a more severely injured and thus less stable joint since it is ultimately the patient who will be applying the pressure of normal or rehabilitative effort to the joint being diagnosed The present invention solves the afore described prob lems of the reversible analog dial type distance indicator requiring intense observer vigilance the problem of the inability to note or to measure force other than at 15 and 20 pound discrete levels and the problem of patient fright by the prior art KT 1000 force indicator being provided in the form of an audible horn with different tones for the 15 and 20 pound levels Such an audible horn is a natural patient fright producer and is thus a severe drawback of the prior art KT 1000 OBJECTS OF THE INVENTION To overcome the disadvantages of the prior art it is an object of the present invention to provide a method of using an improved KT 1000 to measure ankle joint laxity It is a further object of the present invention to eliminate the need for observer vigilance on an analog measure of relative reference pad distance traveled It is yet another object of the present in
39. to the patient by bringing it in contact with the posterior portion of the patient s calf so that the reference pad is adjacent to and capable of pressing upon the patient s Achilles tendon the reference pad so affixed being a tibial reference pad since in position it is disposed adjacent to the patient s tibial bone and c applying force to the respective reference pad and the calcaneous receptacle so as to produce lateral movement therebetween d observing and recording the indication of the amount of lateral distance traveled by the reference pad and the calca neous receptacle relative to each other and e observing and recording the indication of the amount of force applied to produce the relative distance traveled by the reference pad and calcaneous receptacle relative to each other as indicated by the force indicia and f repeating the foregoing steps on the patient s other foot ankle and leg for reference comparison and g repeating the foregoing sequence to observe and record inherent intra patient variability Clinical testing by the inventors of the present invention using the prior art KT 1000 for ankle joint laxity mea surement has proved quite successful despite the manufac turer s indications that ankle joint measurement may be ineffective or impossible with the KT 1000 10 15 20 25 30 35 40 45 50 55 60 65 10 Ten human cadavers were obtained shortly after death A
40. traveled the greater the knee joint laxity The examining doctor s concern in using the prior art KT 1000 is to ensure that the KT 1000 is properly posi tioned and aligned on the knee of the patient and to observe and record how much anterior direction force or posterior 10 15 20 25 35 40 45 50 55 60 65 4 direction force is used and how much instability exists in the knee joint as determined by the number of millimeters of anterior or posterior travel also called translational movement is available to the tibial bone Unfortunately other major disadvantages exist in the prior art KT 1000 surrounding the crucial functions of observation and data recordation by the examining doctor The prior art KT 1000 is provided with a dial type analog indicator for showing the relative distance of reference pad travel The prior art KT 1000 analog dial is marked in incre ments representing millimeters of pad travel and a rotary indicator turns clockwise or counterclockwise to indicate the direction of relative pad movement with the magnitude of distance indicated by the arc traveled by the dial indicator which sweeps out a given number of millimeter increments The prior art analog distance indicator is zero adjustable But the disadvantage in this analog dial type distance indicator is the fact that the examining doctor must keep his or her eyes vigilantly upon the dial to note how much movemen
41. unds of anterior force he or she may have applied and further there is no way for the doctor to know how much force was applied above 15 pounds but below 20 pounds since the 15 pound horn will sound at any applied force level at or above 15 pounds but below 20 pounds Indeed in product literature MEDmetrics president K R Watkins states that t here are several factors other than instrument accuracy which may affect displacement mea surement Physiological variation tester technique condi tioning of patient pretesting activity and apprehension of the patient are a few of these emphasis added Watkins K R introductory remark dated June 1990 San Diego Calif included with KT 1000 The product literature referred to comprises reprints of several studies which product literature is collectively called Knee Stability Measurement Using the KT 1000 Knee Ligament Arthrometer A collection of studies printed in journals compiled by MEDmetric Corporations manu facturers of orthopedic instrumentation including the KT 1000 and dated San Diego Calif June 1990 5 957 869 5 It would be a great advantage to be able to note not only how much anterior joint movement is present and thus how lax the joint is but also to know how much force was needed to produce the anterior joint movement If for example two patients show anterior movements of say 4 millimeters it may also help the examining doctor to know whe
42. us installed the Prior Art KT1000 becomes by virtue of its combination with the receptacle a new device for measuring ankle joint laxity The calcaneous pad modification of the present invention may be easily installed or removed onto or from the KT 1000 by a friction fit sliding channel arrangement In addition the walls of the cube like heel receptacle calcaneous pad in the preferred embodiment are capable of squeezing together in clamp like fashion by a threaded shaft hinge arrangement penetrating through the pad and drawing the cube wing walls toward each other The wing walls thus hinged and positionally adjustable upon the heel of a patient are clamped in place as desired by means of wing nuts disposed on a portion of the threaded hinge shaft which extends outward from the receptacle so that when the wing walls are in a desired position they may be clamped by the friction grasp provided by tightening of the wing nuts In this manner the calcaneous pad is capable of grasping the heel of the patient and thereby the KT 1000 device is stabilized in place in preparation for measurement of ankle joint laxity The calcaneous pad receptacle may be provided with an interior grasping surface of hard rubber or other suitable non slippery material such as a relatively hard elastomer which will not permit the patient s foot to move appreciably In addition when the prior art KT 1000 is used to measure the knee joint laxity the devic
43. vention to elimi nate a noisy and frightening audible horn indication of force applied It is another object of the invention to provide a maximum reading indicator for relative distance traveled by anatomical reference pads It is still another object of the invention to provide a maximum read continuous indication of force applied It is still another object of the invention to provide an improvement to the KT 1000 so as to have a calcaneous reference pad in the form of a receptacle It is yet another object of the invention to provide a receptacle calcaneous reference pad which is clampable and adjustable It is yet another object of the invention to provide a receptacle calcaneous reference pad which is conveniently removable from the prior art KT 1000 and which further can be conveniently installed and removed for switching between use of the improved KT 1000 of the present invention for ankle joint and for knee joint measurement It is also an object of the present invention to overcome the disadvantages of the prior art SUMMARY OF THE INVENTION In keeping with the aforesaid objects of the invention and others which may become apparent the present invention modifies the prior art KT 1000 with novel improvements as follows First the analog distance indicator of the prior art may remain as an analog dial type indicator which is zero adjustable and has radially disposed clock like incremental 10 15 30 35
44. y re settable digital maximum reading indicator for displaying user force applied FIG 8 shows a top view of the Prior Art KT100 having a novel manually re settable analog maximum reading indi cator for displaying relative displacement of the reference pads and a manually re settable plurality of indicator lamps for sequential incremental illumination to display the amount of user force applied FIG 9 shows a top view of the Prior Art KT100 having a novel manually re settable analog maximum reading indi cator for displaying relative displacement of the reference pads and a manually re settable plurality of indicator lamps for sequential incremental illumination to display the amount of user force applied where the indicator lamps have indicia adjacent thereto for indicating the amount of user force applied when each sequential lamp is illuminated FIG 10 shows an exploded view showing the Calcaneous reference pad of the prior art KT1000 in positional relation ship to receptacle and in positional relationship to use of the present invention on the heel of a patient for measuring ankle joint laxity FIG 11 shows a side elevation of the receptacle of the present invention installed on the prior art KT1000 and in position for use in measuring ankle joint laxity of a patient FIG 12 shows a cutaway perspective view of the calca neous receptacle of the present invention installed upon the prior art KT1000 and grasping the heel of a pati
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