Abstract: An artificial implant includes an elongated stem member which is intended for cementless fixation in the medullary canal of a long bone. The stem member is provided with one or more longitudinally extending channels. A porous medium for enabling and encouraging bone ingrowth fixation is bonded to the bottom surface of each channel but is free of the sidewalls of the channel. It has a first outer surface lying in a plane generally parallel to that of the external surface of the stem member and second and third surfaces lying generally, respectively, in angularly spaced radial planes containing the longitudinal axis of the stem member. The resulting implant has a flexibility which can be tailored to that of the bone. Also, the porous medium enables an initial interference fit with the medullary canal of the long bone as well as bone ingrowth fixation over a substantially enlarged surface area than previously possible.

Abstract: A variable position acetabular cup assembly for replacing a natural hip socket includes a symmetrical base cup, a symmetrical polymer bearing, and a nonsymmetrical adapter ring situated between the base cup and the bearing. The base cup is designed to be affixed to the acetabulum to replace the natural socket. The bearing provides a bearing surface for receiving a femur ball. The adapter ring can be mounted on the base cup in a plurality of positions to change the position of the symmetrical bearing after the base cup is secured to the acetabulum.

Abstract: An analog-to-digital converter employs a capacitor circuit for integrating a sample of an input signal during a predetermined interval of time and, thereafter, the capacitor is discharged at a predetermined rate until the integration voltage is equal to that of a reference. The discharge time serves as a measure of the amplitude of the input signal. A measurement interval is established which is equal to an integral number of cycles of each of the possible values of frequency of the A.C. excitation. The signal integration interval has a duration less than or approximately equal to the shortest period of the A.C. excitation, this being the period of the highest frequency A.C. excitation. The signal integration is repeated periodically at each third half-cycle of the highest frequency excitation so that the total integration time experienced during positive half cycles is equal to that experienced during negative half cycles of any of the plurality of excitation frequencies.

Abstract: The invention teaches a method and kit for purifying nucleic acid, such as DNA, from a sample, such as lysed cell or tissue sample. A sample is applied to an anionic exchange matrix column uniformly distributing the sample therein. The column bed is then washed with a weak ionic salt solution which is then removed. The anionic exchange material is optionally primed with an amount strong ionic salt solution which is insufficient to elute the nucleic acid from the column. The priming solution is then removed. An elution buffer is added either directly after the washing step or after the priming step. This is also a strong ionic salt solution of an ionic salt. The elution buffer removes the purified nucleic acid from the material. The method permits purification of nucleic acids without using organic solvents, and, if the priming step is used, in more concentrated form. Uniform distribution of the sample via disturbance of the matrix or column facilitates the purification.

Abstract: A controlled stiffness elongated implant for use in the hip or other appropriate body joint. In the instance of the hip, a ball member fixed to the femur is rotatably engaged with a cup-shaped socket member fixed to the acetabulum of the pelvic bone. The ball member is mounted on one end of a femoral component which has an elongated stem receivable in the intramedullary canal of the femur. The stem has a generally longitudinally directed reduced mid-stem section. The dimension of the reduced mid-stem section is uniform or variable between the proximal and distal ends so as to affect the mass moment of inertia at any given location along the length of said stem to thereby achieve an optimal stem flexibility.

Abstract: The invention relates to a composition useful in determining an analyte in a sample. The composition contains an indicator system which forms a detectable signal in the presence of said analyte, and which is not a coupling system, as well as a pyrogallol derivative. The pyrogallol derivative causes uniform formation of detectable signal. Also described are kits useful in determining an analyte, apparatus which incorporate the composition, and a method for determining an analyte using the composition.

Abstract: A transmission for converting rotary motion to simultaneous reciprocating motion of a tool in two mutually transverse directions. A driver is selectively attached to one end of an input shaft and the opposite end of the input shaft terminates at an eccentric cam. An output shaft extends between a driven end and a working end. The driven end is apertured to rotatably receive the eccentric cam and the output shaft is slidably received in the diametrically extending bore of a spherical bearing member. Upon rotation of the input shaft, the working end of the output shaft is caused to reciprocate toward and away from the input shaft and, simultaneously, laterally relative to a longitudinal axis of the input shaft. The working end of the output shaft may be provided with appropriate cutting teeth to enable its use, for example, as a power broach for the precise removal of bone to enable proper implantation of a prosthetic device.

Abstract: A regulated power supply employs two separate sources of power which are serially connected by a variable impedance element, such as a transistor, connected between the two power sources. Output voltage of the power supply is equal to the sum of the individual power supply voltages minus a voltage drop across the variable impedance element. A sensor circuit employing standby and active mode branches is coupled between output terminals of the power supply for control of the variable impedance element. The active branch of the sensor is switchably connected to an output power terminal of the supply so as to be operative only during the active mode. The standby branch comprises a resistive network coupled to a reference diode while the active branch comprises a feedback amplifier coupled to the reference diode.

Abstract: A dynamic bone fixation screw for rejoining fracture fragments of a bone to their approximate original mutual dispositions. It includes a threaded distal end member for threaded engagement with one of the bone fragments and a head member at a proximal end for engagement with another of the bone fragments. A spring member integral with and extending between the distal end member and the head member enables a predetermined torque to be initially imparted to the bone. When stress relaxation in the bone occurs, the spring member relaxes accordingly while continuing to draw the bone fragments together. The bone screw is fabricated in a unique manner.

Abstract: A fixation system is disclosed for an elongated prosthesis such as a prosthetic ligament. Opposed ends of the ligament are attached to spaced apart bones such that the connections are external of the bones so as to permit a maximum of relative movement between the ligament and the bones while assuring requisite strength in tension. The design enables pretensioning of the ligament, guards against abrasion of the ligament by reason of moving contact with the bones, and is adjustable to accommodate a variety of required sizes.

Abstract: An apparatus for placing a bone cutting saw cutting guide adjacent a proximal surface of a human tibia bone having an elongated rod inserted into the tibia for clampingly supporting a rotating bar on the central longitudinal axis of the tibia bone. The bar being extended from the rod and connected to a pivot device which in turn is connected to a support arm that holds a saw cutting guide against a proximal portion of the tibia bone. The rotation angle of the rod determining the medial-lateral inclination of the saw cutting guide and the pivot device determining the anterior-posterior inclination of the saw cutting guide. The support arm is adjustable in length to determine the height of the saw cutting guide.

Abstract: A fluted and cannulated self-tapping bone screw which can be guided into proper position using a guide pin that slidably fits in the cannula of the bone screw. The flutes have cutting edges centered on axial centerline of the cannula.

Abstract: A dynamic bone fixation screw for rejoining fracture fragments of a bone to their approximate original mutual dispostion. It includes a threaded distal end member for threaded engagment with one of the bone fragments and a head member at a proximal end for engagement with another of the bone fragments. A spring member integral with and extending between the distal end member and the head member enables a predetermined torque to be initially imparted to the bone. When stress relaxation in the bone occurs, the spring member relaxes accordingly while continuing to draw the bone fragments together. The bone screw is fabricated in a unique manner.

Abstract: A fixation system for drawing together into engaging relationship mutually opposed fracture surfaces of a pair of bone fragments at a fracture site. An elongated blade with a sharpened leading end is driven into a first bone fragment generally parallel to and spaced from a fracture surface of the first bone fragment. A flange member integral with the blade extends transverse of the blade and overlies the fracture site between the first and second bone fragments. At least one screw fastener with a head and threaded shank extends through an opening in the flange and is threaded into the second bone fragment along an axis which extends away from the blade.

Abstract: A composition useful in determining analytes, such as glucose or cholesterol, is disclosed. The composition contains an enzyme which specifically reacts with the analyte to be determined, a soluble ferricyanide compound which is reducible to form a ferrocyanide, a soluble ferric compound which provides ferric ions for reacting with ferrocyanide to form a reaction product, and a buffer which does not prevent formation of this reaction product. The composition has a pH of from about 3.0 to about 6.0.

Abstract: A method and apparatus for modifying the distal end of the humerus deformed by injury or disease in preparation for fixation of an elbow joint replacement. A through hole is first formed in the superior aspect of the olecranon fossa communicating with the humeral canal. A stem member which extends from the platform of a distal cut guide tool is received through the hole and extends into the humeral canal. The distal cut guide tool is held so that the platform is generally coplanar with the junction of the medial epicondyle and the trochlea with proper inclinations, both in an anterior view and in a lateral view. Thereupon, a first resected surface is formed by sawing, using as a guide, a planar guiding surface provided on the platform.

Abstract: A carefully controlled amount of hydrogen is diffused into titanium or its alloys at an elevated temperature above the transformation temperature. After the elevated temperature is maintained for an approprate duration of time, eutectoid transformation is performed in an inert atmosphere, again for an appropriate period of time, during which or alternatively after which the hydrogen is removed and the metal cooled to room temperature. A sintered titanium alloy component of the type intended for use as a joint replacement subjected to such a treatment displays a fatigue strength which is noticeably improved over a similar article with an equiaxed or lamellar microstructure.

Abstract: A structural joint which may be for orthopedic use is effective to simultaneously resist bending and torsional loading. It includes a female member formed with a cone shaped bore and a mouth defining entry into the bore. A male member matingly engageable with the female member has a contoured outer surface which includes a coupling element sized and shaped for mating engagement with the bore. When the male and female members are joined, the coupling element extends to a location within the bore spaced from the mouth and joins, via a smooth surfaced intermediate element, to a transitional element whose transverse dimension is substantially smaller than the mouth of the bore as it extends through and beyond the mouth. The bore and the coupling element may be mutually tapered such that the male and female members become locked together when engaged.

Abstract: A cementless acetabular implant intended for use in instances of a bony defect in the pelvis at the acetabular cavity requiring substantial rebuilding of the acetabulum by use of bone graft material. It includes a substantially rigid metallic hemispherically shaped support cup for contiguous reception with the bone within the acetabular cavity. A flange extends outwardly from a peripheral rim of the support cup for supportive engagement on bone stock located beyond the acetabular cavity. The flange also serves to contain the bone graft material. The outer convex surface of the support cup is porous, as is a medial surface of the flange, to accept bone ingrowth. A bearing insert of low friction material for receiving the ball of a femoral prosthetic component is mounted in contiguous engagement with an inner surface of the support cup.

Abstract: A hand-held drill jig is utilized to locate and maintain a central axis through a head and an associated neck of a femur enabling a blind hole to be drilled into the femoral head oriented to the central axis. The drill jig is adjustable to accommodate a broad range of sizes of femurs and can be readily attached to, then removed from, the femur. A positioning mechanism is provided to firmly engage both the outer peripheral surface of the femoral head and the femoral neck. This operation renders associated drill bushing immobile relative to the femur and orients its longitudinal axis with the central axis. A drill bit is then capable of being guided through the drill bushing and into cutting engagement with the femoral head.