Wedge-shaped spacer for correction of deformed extremities

• US 5,766,251 A
• Filed: 11/15/1996
• Issued: 06/16/1998
• Est. Priority Date: 03/13/1992
• Status: Expired due to Fees

• Current Assignee: Tomihisa Koshino
• Original Assignee: Tomihisa Koshino
• Inventors: Koshino, Tomihisa
• Primary Examiner(s): Weiss, John G.
• Assistant Examiner(s): Snow, Bruce E.
• Application Number:
  US08/749,678
• Time in Patent Office: 578 Days
• Field of Search: 623/16, 623/17-18, 623/20, 606/59-61, 606/63, 606/65, 606/67, 606/69-72, 606/88
• US Class Current: 623/11.11
• CPC Class Codes: A61B 17/8095 Wedge osteotomy devices
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30724 Spacers for centering an implant in a bone cavity, e.g. in a cement-receiving cavity
• CPC Class Codes: A61F 2002/2835 Bone graft implants for filling a bony defect or an endoprosthesis cavity, e.g. by synthetic material or biological material
• CPC Class Codes: A61F 2002/2892 Tibia
• CPC Class Codes: A61F 2002/30153 rectangular
• CPC Class Codes: A61F 2002/30158 trapezoidal
• CPC Class Codes: A61F 2002/30266 wedge-shaped parallelepipeds
• CPC Class Codes: A61F 2002/3028 polyhedral different from parallelepipedal and pyramidal
• CPC Class Codes: A61F 2002/30574 with an integral complete or partial collar or flange
• CPC Class Codes: A61F 2002/30736 Augments or augmentation pieces, e.g. wedges or blocks for bridging a bone defect
• CPC Class Codes: A61F 2002/30777 Oblong apertures
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30843 Pyramidally-shaped
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2230/0019 rectangular
• CPC Class Codes: A61F 2230/0026 trapezoidal
• CPC Class Codes: A61F 2230/0063 Three-dimensional shapes
• CPC Class Codes: A61F 2230/0082 parallelepipedal
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61L 27/12 : Phosphorus-containing materials, e.g. apatite

Abstract

A wedge-shaped spacer usable for varus, valgus, flexion, extension and derotation osteotomies such as corrective osteotomy for femoral shaft deformity, supracondylar osteotomy of the femur, intraarticular osteotomy of the femur, intraarticular osteotomy of the tibia, high tibial osteotomy and subtuberosity osteotomy of the tibia, supramalleolar osteotomy of the tibia and, corrective osteotomy of the calcaneus, is made of a sintered hydroxyapatite provided with a plurality of pores having a pore size of 50 to 250 μm and connected with each other and with the outside through a plurality of capillaries having a thickness of 0.5 to 5 μm, and having a compression strength of 300 kg/cm² and a porosity of 30 to 50%, and which spacer has at least one thorn-shaped projection extending outwardly in a projecting direction from at least one of the upper and lower surface thereof, and at least one hole extending from the upper surface to the lower surface therethrough in parallel to the projecting direction of the thorn-shaped projection.

Claims

1. A wedge-shaped spacer usable for varus, valgus, flexion, extension and derotation osteotomies comprising a sintering product of hydroxyapatite which is provided with a plurality of pores having a pore size of 50 to 250 μ

m and connected with each other and with the outside through a plurality of capillaries having a thickness of 0.5 to 5 μ

m, and has a compression strength of 300 kg/cm² and a porosity of 30 to 50%, and

having an upper surface and a lower surface, at least one thorn-shaped projection extending outwardly in a projecting direction from at least one of the upper and lower surface, and at least one hole extending from the upper surface to the lower surface through the wedge-shaped spacer in parallel to the projecting direction of the thorn-shaped projection.

2. The wedge-shaped spacer of claim 1 usable for varus, valgus, flexion, extension and derotation osteotomies wherein the hole has a polygonal cross-sectional profile.

3. The wedge-shaped spacer of claim 1 usable for varus, valgus, flexion, extension and derotation osteotomies wherein the upper and lower surfaces of the wedge-shaped spacer are inclined in relation to each other at an angle of 5 to 15 degrees.

4. The wedge-shaped spacer of claim 1 usable for varus, valgus, flexion, extension and derotation osteotomies wherein the thorn-shaped projection has a height of 2 to 4 mm.

5. The wedge-shaped spacer of claim 1 usable for varus, valgus, flexion, extension and derotation osteotomies wherein a plate member is attached to a head portion of the wedge-shaped spacer.