New York Society for the Relief of the Ruptured and Crippled,

The Sampson Corporation

New York Society for the Ruptured and Crippled Maintaining the Hospital

New York Society for the Ruptured and Crippled Maintaining the Hospital for Special Surgery

New York Society for the Relief of the Ruptured and Crippled Maintaining

Albert H Burstein

Chitranjan S Ranawat

Donald L Bartel

Thomas P Sculco

Allan E Inglis

Timothy M Wright

Joseph David Lipman

John N Insall

Bruce H Robie

Joseph M Lane

Bertram L Koslin

Jeffrey S Bennett

James C Otis

Stephen Li

Jordan Ryalls

Kingsbury G Heiple

Lee R Straub

An instrument is provided for use in shaping a femur preparatory to implantation of a knee prosthesis. A gap checking device is fixed to the distal end of the patient's femur and referenced to the epicondyles of the femur. The gap checking device includes slots through which a cutting instrument can be passed to shape the femur so that it can receive the femoral component of the prosthesis. One of the slots enables the distal femoral cut to be made. The thickness of the gap checking device is selected so that the distance between the distal femoral cut and the distal surface of the gap checking device plus the thickness of a shim resting on the cut proximal tibia surface is equal to the combined thickness of the tibial and femoral components of the prosthesis. This enables balancing of the ligaments to be checked before the femoral cuts are made, but while the gap checking device is secured to the femur.

Method and apparatus for femoral resection

Shaped articles made from molded ultra high molecular weight polyethylene (UHMWPE) with an average molecular weight of between about 1 million and about 10 million and exhibiting a low modulus of elasticity throughout the shaped article or in selected regions of the shaped article are disclosed. These articles are produced by filling a mold with powdered UHMWPE, covering the mold with a piston, raising the temperature of the mold and its contents to between about 140.degree. and about 225.degree. C. while simultaneously applying a pressure of between about 2.5 and about 15 MPa to the mold and its contents, maintaining the pressure and temperature for between about 5 and about 25 minutes, with the time selected dependent upon the thickness of the molded part, then dropping the temperature of the molded part, either completely or in part at a rate between about 4.degree. and about 175.degree. C./minute either while maintaining the mold at the molding pressure, at pressure less than the molding pressure or under no external applied pressure. The shaped articles so produced exhibit a combination of properties including an elastic modules between about 500 MPA and about 800 MPA, a yield strength equal to or greater than about 20 Mpa, an elongation to rupture of greater than about 300%, crystallinity and density less than or equal to about that of the native powdered UHMWPE used to form the part and a melting point less than or equal to about that of native UHMWPE powder that has experienced melting and cooling at ambient pressure. The shaped articles are useful as the bearing surface of total knee joints, prosthetic hip joint cups and as other prosthetic shapes for replacement of other joints of the human body.

Process for producing ultra-high molecular weight low modulus

A knee joint prosthesis comprises femoral and tibial components. The femoral component includes a pair of condyles each curved generally to match the shape of an anatomical femoral condyle. The surface of each condyle is defined by (a) anterior posterior radii R.sub.CF and R.sub.CE, wherein R.sub.CF is the radius of curvature Of that portion of the condyle which is weight bearing in flexion and R.sub.CE represents that portion of the curvature of the condyle which is weight bearing in extension, and (b) a medial lateral radius R.sub.CML. The tibial component includes a pair of concavities, each of which is adapted to receive one of the condyles of the femoral component. The surfaces of the concavities are defined by an anterior posterior radius R.sub.TAP and a medial lateral radius R.sub.TML. The foregoing radii are selected to optimize the balance between range of motion and knee longevity.

Joint prosthesis

A bone fracture fixation device for stabilizing a fracture of a portion of a long bone overlying or closely adjacent to a prosthetic joint component comprises a fixation plate that is held adjacent to the bone by clamps joined to it by screws. The fixation plate and clamps have spikes that penetrate partly into the bone to fix the bone to the device and stabilize the fracture but that also remain partly outside the bone and serve as spacers to hold the plate and clamps spaced apart from the bone, thereby leaving the periosteum undisturbed and preserving good blood distribution to the bone at the fracture site and hence good conditions for healing of the fracture.

Bone fracture fixation device

A bone prosthesis for the leg and thigh comprises a distal femoral component that includes a body portion adapted to replace a resected portion of the distal femur and a condylar portion having a spherical surface along its inferior and posterior aspects and an axle hole extending through it in the latero-medial direction at the geometric center of the sperical surface and a proximal tibial component that includes a metal head portion having a cavity opening superiorly and defined by spaced-apart lateral and medial flange portions, each of which has an axle hole. A plastic tibial plateau insert is received in the cavity of the tibial head portion and has a spherical seat matching, receiving and pivotably supporting the femoral condylar spherical surface. A plastic bushing is received in the axle hole of each tibial flange portion, and a metal axle is received in the femoral and tibial axle holes. Clearances between the bushings and the portions of the axle received in the bushings provide latero-medial flexural and axial rotational laxities in the prosthetic joint throughout the range of flexural motion. A shaft component is used interchangeably to replace portions of the tibial and femoral shafts. A diaphysis component is provided or total femoral replacement. A proximal femoral component, used in conjunction with the shaft component or diaphysis component, replaces the femoral part of the hip joint. Identical Morse-type taper couplings are used to connect shaft components to joint components.

Bone prosthesis for the leg and thigh

An elbow joint prosthesis having a metal humeral component, the head of which has flanges forming a recess in which a U-shaped plastic insert is nested. A boss projecting anteriorly from the head portion of a metal ulnar component is received within the insert with latero-medial clearance for laxity. A tubular plastic sleeve is received in axle holes in the ulnar boss and the legs of the plastic insert, and an axle spanning the flanges of the humeral component and extending through the sleeve bore connects the ulnar component to the humeral component for articulation. Clearance between the sleeve and the axle hole of the ulnar boss provides laxity up to nominal limits, beyond which elastic deformation of plastic at contact areas of the sleeve and insert restrains rotational and angular motions under supination, pronation and varus-valgus angulation of the arm, absorbing energy in the process. Lateral and medial protuberances on the proximal portion of the humeral head enhance support of the humeral component in strong bone of the distal humerus at the border of the olecranon depression.

Elbow joint prosthesis

A femoral component for a hip joint prosthesis comprises a proximal portion adapted to be received in the intertrochanteric region of a femur, a neck portion extending obliquely medially, anteriorly and superiorly from the proximal portion and adapted to be joined to a femoral head element, and a stem portion smoothly merging with and extending inferiorly from the proximal portion. The proximal portion has anterior and prosterior aspects that converge medially and inferiorly and intersect a rounded medial aspect oriented obliquely to the stem portion both anteriorly and medially, said aspects defining a generally wedge-shaped body adapted to engage the endosteal surfaces of the femur in the intertrochanteric region such that substantially all loads are transmitted from the component to the bone in the intertrochanteric region and load transfers through other surfaces are minimized.

Femoral prosthesis for total hip replacement

A prosthesis for replacement of the first metatarsal-phalangeal articulation comprises a metatarsal component and a phalangeal component. The metatarsal component has a convex articulating surface and concave distal aspect, the metatarsal articulating surface being curved so as to approximate the natural articular surface of the first metatarsal bone and furthermore to articulate smoothly with the phalangeal articulating surface of the phalangeal component. The phalangeal component comprises a base member and an insert, the base member having a distal aspect adapted to engage and be secured to a resected end of the phalanx bone and also having a proximal aspect adapted to receive and have permanently attached thereto the insert. The insert, which includes the phalangeal articulating surface, is made available in various distal-proximal thicknesses, and an appropriately sized insert is selected during implantation so as to cause the tension in the natural soft tissue surrounding the prosthesis after implantation to approximate the tension of the soft tissue of the natural metatarsal-phalangeal articulation.

Metatarsal-phalangeal prosthesis

A wrist joint prosthesis comprises a metal radial component and a metal metacarpal component connected by a metal axle and providing triaxial motions that are comparable to those of the anatomical wrist joint and restraint of excessive motions. Energy is absorbed and shock loads are minimized by the interposition of a bearing member between the radial and metacarpal components and a bearing sleeve of polymeric material over the axle.

Wrist joint prosthesis

A total hip joint prosthesis has a ball, replacing the ball of the hip joint ball and socket, affixed to the femur by a stem. Stem stress is reduced by providing a rounded cross-section of the stem truncated along the lateral side in the critical section subject to greatest cyclic loading. The stem is of controlled low flexibility so that when the bone cement and stem composite structure is in place, the bone is subject to a maximum percent of normal stress from bending moments. By virtue of the truncated shape and its size relative to the bone cavity, stress in the stem is minimized when the stem alone carries the load.

Hip joint prosthesis

A box-like recess between the condylar portions of the femoral component has a transverse convexly curved cam follower portion at the posterior extremity of a superior wall which engages a concave cam surface at the inferior portion of the posterior surface of a tibial post that extends up from the plateau surface of the tibial component into the recess. The camming action between the cam follower and cam surface forces the zones of contact between the condylar portions of the femoral component and concavities in the tibial component posteriorly as the leg approaches full flexion, thereby increasing the range of flexion without interference between posterior surfaces of the femur and the tibial component and preventing anterior dislocation of the femur. The plateau of the tibial component slopes inferiorly and posteriorly, also to increase the range of flexion without interference.

Posteriorly stabilized total knee joint prosthesis

A woven basket is placed over the stem of a prosthesis and receives bone cement therewithin and through its intersticies. The resulting prosthesis-to-bone interface greatly improves the distribution of forces transferred to the bone.

Prosthesis-to-bone interface system

A fluted hip nail implant system for orthopaedic surgery for use in repair of fractures of the hip or for stabilization of surgically created fractures in the reconstruction of congenital deformaties of the hip. A single piece fluted hip nail with depending bone plate having a specially designed junction between the nail portion and the bone plate adapted to receive instrumentation for use in insertion and removal of the implant. The hip nail portion is formed with flutes terminating in sharp tips for cutting into the bone and providing torsional rigidity. A bone clamp tool having a ball member adapted to be received in a recess on the bone plate assists in clamping the bone plate to a femur to permit application of surgical screws.

Fluted hip nail implant system for orthopaedic surgery

A sub-trochanteric intramedullary rod for use in fracture fixation in the femur characterized in that it is fluted throughout its length and has a minor portion of a diameter greater than its major portion, thereby being of stepped configuration. The distal ends of the flutes in each of the major and minor portions have sharp points thereon adapted to cut into bone and means are provided beneath the points to receive bone particles and chips cut by the points.

Growing community of inventors

Stamford, CT, United States of America

Albert H Burstein