A method for determining the hip joint laxity of a dog includes the steps of positioning the hip joints of the dog, in a coordinate system having three degrees of freedom, a first degree of freedom for flexion and extension of the hip joint, a second degree of freedom for adduction and abduction of the hip joint, and a third degree of freedom for internal and external rotation of the hip joint, where a neutral position is defined as positioning of an axis of the femur perpendicular to a plane defined by both ischiatic tuberosities and both cranial dorsal iliac spines and where both femoral condyles are perpendicular to the long axis of the pelvis, between 10 degrees of flexion and 30 degrees of extension, between about 10 and about 30 degrees of abduction, and from about zero degrees of rotation to about 10 degrees of external rotation; applying a lateral outward force on the femoral head, the magnitude of the force being sufficient to cause the hip to enter a high stiffness region and, while maintaining the lateral outward force on the femoral head, obtaining a radiographic image of the hip.
A method for measuring functional laxity in a dog for determining presence of or absence of canine hip dysplasia is provided by placing the dog in a weight-bearing position; and assessing hip joint subluxation by an imaging technique by estimating a degree of dorsolateral subluxation for each hip joint of the positioned dog, with the degree of dorsolateral subluxation determined by measuring the portion of femoral head medial to the acetabulum. Also provided is an apparatus for placement and positioning of a dog, being evaluated for canine hip dysplasia, in a weight-bearing position.
A method for distracting a coxofemoral joint of a patient having two hind legs includes the steps of placing the patient in ventral recumbency, positioning a distractor between the upper thighs so that the distractor acts as a fulcrum for lateral displacement of the coxofemoral joint, and applying inward pressure to the stifle regions to distract the coxofemoral joint. Related methods are also disclosed for imaging a distracted coxofemoral joint and for evaluating the likelihood of developing laxity of a coxofemoral joint in a patient. The imaging can be non-radiographic. A distractor apparatus, suitable for use in the methods, is also described.
In order to avoid the use of a marking element on the pelvic bone in a method for determining the mechanical axis of a femur, with which the femur is moved about the hip joint, the movement of the femur is followed via a navigation system by means of a marking element on the femur, position data of the femur obtained therefrom are stored and the position of the mechanical axis of the femur is calculated relative to the same from the various position data of the femur in various positions, it is suggested that the femur be pivoted from an initial position only through a maximum pivoting angle of 15.degree. in various directions and that the mechanical axis of the femur be calculated from the position data of the surface area thereby covered by the marking element and from the position data of the knee joint otherwise determined. In addition, a device for carrying out this method is described.
A distractor frame comprises an upper pin, a lower pin positioned substantially parallel to the upper pin, a pair of adjustment mechanisms, wherein each adjustment mechanism couples to the upper pin and the lower pin such that each adjustment mechanism is positioned generally perpendicular to the upper and lower pins, wherein each adjustment mechanism comprises a shaft, a first pin connector for coupling the upper pin to the shaft, a threaded rod coupled to an end of the shaft, a cylindrical sleeve adapted for threadedly engaging the threaded rod, such that a portion of the shaft and a portion of the threaded rod may be positioned within the cylindrical sleeve, and a second pin connector coupled to the cylindrical sleeve for coupling the lower pin.
