Abstract: The present invention relates to prosthetic knee devices providing for an expanded range of translational movement without substantially reducing the risk of inadvertent dislocation of the knee when implanted. The devices of the invention achieve the expanded range of motion without requiring a substantial posterioral shifting of the points of contact between the femoral and tibial components. The prostheses of the invention also reduce the risk of breakdown of the plastic components of the prosthesis and the underlying resectioned proximal tibia surface by providing an expanded, winged fixation post.

Abstract: Disclosed is a product which includes calcium carbonate and bone growth factor useful for the promotion of bone formation when implanted in the body. The calcium carbonate is preferably in the form of aragonite which can be recovered from naturally occurring coral. A preferred bone growth factor of the present invention is a protein mixture purified from bone. Also disclosed is a process for the induction of bone formation which includes implanting the product in a body. The product and process of the present invention are particularly useful in hip replacement operations, knee replacement operations, spinal fusion operations, repair of periodontal defects, treatment of osteoporosis, repair of bone tumor defects and repair of bone fractures.

Abstract: An intercondylar notch cutter using a plunge milling bit and bit guide which engages parallel tracks in a trial prosthesis. The intercondylar notch cutter comprises a cutting bit and a guide sleeve. The cutting bit can be thrust into the femur and then translated through the femur cutting a notch without removing the trial prosthesis. The bit is supported by a guide or housing with a guide platform which extends medially and laterally from the guide. Two condyle articulating surfaces on the platform slidingly engage a condyle surface on a trial prosthesis. Along the condyle surfaces on the trial prosthesis are two parallel grooves. Posts on the notch cutter are slidingly received within the grooves. A surgeon first places the trial implant on the femur without cutting an intercondylar notch. The surgeon can proceed immediately to cut an intercondyle notch without removing the femoral trial prosthesis.

Abstract: An orthopedic instrument having a quarter-turn disconnect apparatus. A female socket is provided on a broach or cutting instrument and a male plug with a locking mechanism is provided on a cutting apparatus. The male plug is inserted into the socket and pushed forward slightly against the resistance of a spring. The plug or socket are then turned one-quarter turn at which point the locking mechanism falls into place.

Abstract: An orthopedic bone plug cutter for cutting a customized bone plug for use with prosthesis having stems of complex geometry, such as a cruciate stem. The bone plug cutter comprises an anvil which supports a piece of bone obtained intraoperatively. A specialized cutting head is forced against the anvil by a parallel jaw clamp. The cutting head can then be removed from the clamp and the bone plug extruded from the cutter with a plunger.

Abstract: A patella planer for preparing a resected surface on a patella in a single operation. The patella planer has an adjustable stop which can be used on either side of the planer so that the planer may be used on the right or left knee. The adjustable stop has a floating zero pointer which can be set to accommodate varying thickness of the patient's patella. The amount of patella material to be removed can be selected by adjusting an offset stop pin.

Abstract: A prosthesis having a proximal portion of a stem formed as a wedge having opposed tapers such that prostheses can be thrust into a medullary canal and achieve fixation without unduly stressing the cortical bone remaining in the femur. Ribs secure the prosthesis against medial-lateral motion. Simultaneously, a degree of flexibility is provided in an anterior-posterior direction. A slotted distal portion of the stem is flared to enhance fixation distally.

Abstract: A tibial knee prosthesis having a plastic or polyethylene prosthesis body comprising an articulating surface and medullary stem. An intermediate metal plate locks on to the medullary stem and fits between the articulating surface and a resected proximal surface of the tibia. A distal surface of the plate may be provided with a porous coating adjacent the proximal resected surface of the tibia, to encourage bone ingrowth and fixation.

Abstract: A surgical jig for orienting a femoral component of a prosthetic knee prosthesis angularly with respect to the axis of the patient's femur which jig utilizes a single drill plate or guide for condylar pins, but permits variation in the placement of those pins. The jig comprises a distal plate which is placed against the distal end of the femur. The distal plate has two condyle fingers for grasping the posterior side of the femoral condyles. Gage means are provided to measure the size of the distal end of the femur. A rotatable drill guide permits the surgeon to adjust the placement of two drill bores for receiving condyle pins on a femoral component of a knee prosthesis.

Abstract: A jig for resecting the distal end of a femur to receive a femoral component of a knee prosthesis. The jig has independent medial and lateral condyle sagittal saw guides. The guides aid a surgeon in cutting three of four resected surfaces or planes for each condyle. The femoral component accepts shims over either condyle to compensate for uneven loss of healthy bone. The shims do not change the internal geometry of the femoral component, but associate each proximal displacement with an anterior displacement of the geometry. Each saw guide slides on a slanted dovetail track so that the proper amount of anterior displacement can be maintained so that shims may maintain the common internal geometry.

Abstract: An apparatus for disassembling a head and acetabular component of a bipolar orthopedic hip prosthesis. The head includes a female taper configured for engaging a corresponding male taper of a femoral component of a hip prosthesis. The acetabular component includes a cavity in which the head is elastically constrained. The apparatus includes a rod having a male taper at one end thereof sized and configured to be received in taper locking engagement in the female taper of the head of the bipolar prosthesis. The rod has external threads that engage internal threads of a sleeve surrounding the rod. The sleeve includes a thrust surface at one end that engages the acetabular component as the sleeve is rotated relative to the rod. The sleeve causes the acetabular component to be pressed off of the head while the head remains taper locked to the rod. Continued rotation of the sleeve causes the head to be pressed off of the taper of the rod.

Abstract: A posterior stabilized knee prosthesis with removable pin in the femoral component. The removable pin has a tapered split ring lock which prevents the pin from backing out. A split ring is provided on the pin which rides in a groove on the pin. When the pin is properly seated, the split ring engages a corresponding groove within the femoral prosthesis, locking the pin in place. Chamfers are provided on both the front and back of the split ring so that the split ring will compress as the pin is being screwed into the femoral component and also so that the pin can be removed if necessary.

Abstract: An orthopedic jig or saw guide for preparing a femoral knee joint to receive the femoral component of a posterior stabilized prosthesis. The jig is adapted for cutting a central cavity in the distal end of the femur. In one embodiment, the cavity has a curved surface, the curve extending medial-laterally and a curved osteotome for incising a curved surface between the resulting two longitudinal incisions. The jig further comprises longitudinal saw guides for guiding a sagittal saw to make appropriate incisions parallel to the longitudinal axis of a femur.

Abstract: An implantable prosthesis comprises a polyethylene prosthetic member that is substantially transparent to x-rays and a radiographic marker that is substantially opaque to x-rays. The radiographic marker is configured as a tension spring arranged as a continuous ring encircling the prosthetic member.

Abstract: A spacer to be used with femoral hip prostheses. The spacer is placed under a existing collar of a femoral hip prosthesis and cemented or tied in place or both. The spacer comprises a U-shaped segment adapted to fit under a medial collar and partially enclose part of a proximal portion of the stem of a hip prosthesis. Spacer plugs are provided to offset the spacer slightly and provide a space which is filled with bone cement (PMMA), securely attaching the spacer to the prosthesis. A distal ledge which lies adjacent the proximal body of the prosthesis keeps the cement enclosed between the stem and the spacer. An area of porous coating is provided distally. A peripheral groove is also provided.

Abstract: A tibial spacer saw guide for guiding the resection of a bony defect of the lateral or medial condyle of the proximal tibia to accommodate a spacer to be implanted beneath a tibial baseplate of a tibial prosthesis. The saw guide includes a plate having a plurality of locating holes corresponding in spacing and location to pins extending from the inferior surface of the tibial baseplate. The plate has medial and lateral guide edges for guiding a sagittal osteotomy where the guide edges are located relative to the locating holes, and thus relative to the pegs of the tibial baseplate. The saw guide also includes an anterior block extending from the plate and having a plurality of slots for guiding a horizontal osteotomy for the spacer of selected depth. The plate rests on an initially resected surface, and thus the horizontal osteotomy for the spacer is located relative to the initial osteotomy surface.

Abstract: A method for purifying bone-derived osteoinductive factors including an ultrafiltration process, an anion exchange process, a cation exchange process, and a reverse phase HPLC process. The ultrafiltration process preferably includes a first ultrafiltration step using a membrane having a nominal molecular weight cutoff of approximately 100 kilodaltons (kD) and a second ultrafiltration step employing a membrane having a nominal molecular weight cutoff of approximately 10 kD. For the anion exchange process, a strongly cationic resin is used, preferably having quaternary amine functional groups. Typically, the eluant for the anion exchange process has a conductivity from about 10,260 micromhos (.mu.mhos) (1.026.times.10.sup.-2 siemens (S)) to about 11,200 .mu.mhos (1.120.times.10.sup.-2 S). For the cation exchange process, a strongly anionic resin is used, preferably having sulfonic acid functional groups. The eluant for the cation exchange process typically has a conductivity from about 39,100 .mu.mhos (3.91.

Abstract: A prosthesis having a proximal portion of a stem formed as a wedge having opposed tapers such that prostheses can be thrust into a medullary canal and achieve fixation without unduly stressing the cortical bone remaining in the femur. Ribs secure the prosthesis against medial-lateral motion. Simultaneously, a degree of flexibility is provided in an anterior-posterior direction. A slotted distal portion of the stem is flared to enhance fixation distally.

Abstract: An apparatus for detecting an electrical potential in a human body to control the delivery of a therapy. The electrical potential comprises a principal signal and a baseline signal. The apparatus samples the potential through an electrode during a selected interval and stores the value of that potential at the end of the interval. The stored value of the potential will be restored as an initial condition on the electrode at the end of a second interval after delivery of the therapy. In a heart pacemaker, the baseline signal is useful for controlling the output pulses of the pacemaker. The apparatus permits sensing of the baseline signal despite stimulating pulses and charge canceling.

Abstract: An medullary caliper comprising a sleeve or tube with internally actuated caliper arms at a distal end thereof. The sleeve is graduated so that the depth at which a measurement is being taken can be immediately determined. A control rod extends the caliper arms radially outward within the medullary canal to perform the measurement. Displacement of the control rod is translated by a scale into a direct reading of the diametric dimension of the medullary canal.