It is difficult during joint replacement within the human body to maintain the exact overall leg dimension after surgery. This is especially true when large joints such as hips, are repaired and or completely replaced.
One method for comparing leg length before and after hip surgery is described within U.S. Pat. No. 6,027,507 entitled xe2x80x9cLeg Length Gauge for Total Hip Replacementxe2x80x9d, wherein a removable gauge having pin-receiving apertures is employed.
U.S. Pat. No. 5,606,590 entitled xe2x80x9cSurgical Laser Beam-based Alignment System and Methodxe2x80x9d describes a sophisticated x-ray console that includes a laser source and lens for providing alignment during orthopedic surgery.
A further use of a laser distance detector for manufacturing operations is found in U.S. Pat. No. 4,733,969 entitled xe2x80x9cLaser Probe for Determining Distance.xe2x80x9d This arrangement employs lenses along with an electronic circuit, which functions as a coordinate measuring machine.
It would be economically advantageous to utilize the precision focus of inexpensive laser diodes, per se, without having to provide lenses and electronic circuits for distance determination during medical procedures.
One purpose of the instant invention is to provide a simple, non-invasive arrangement of laser diodes for determining pre-operative and post-operative limb and joint distance for maintaining or correcting the distance after surgical joint replacement.
A hand-held measurement console and surgical position indicator in the form of an enclosure containing a pair of spaced lasers is used in conjunction with a pair of temporary markers in the form of screws, indelible markings and the like, to determine a reference distance prior to joint replacement surgery. Immediately after surgery, the lasers are directed on the temporary markers to compare the post surgery distance to the reference distance and appropriate adjustments are made to cause the post-surgery distance to correspond to the pre-surgery reference distance or the desired leg length correction.
USPTO Backgrounds
USPTO Backgrounds