Femoral tensing and sizing device

• US 6,056,756 A
• Filed: 08/11/1998
• Issued: 05/02/2000
• Est. Priority Date: 08/11/1998
• Status: Expired due to Term

• Current Assignee: DePuy Orthopaedics Incorporated (Johnson & Johnson)
• Original Assignee: Johnson and Johnson Professional Inc (Johnson & Johnson)
• Inventors: Slamin, John, Colleran, Dennis, Eng, Lisanne
• Primary Examiner(s): Smith, Jeffrey A.
• Application Number:
  US09/132,279
• Time in Patent Office: 630 Days
• Field of Search: 606/86, 606/87, 606/88, 606/90, 606/96, 606/102
• US Class Current: 606/87
• CPC Class Codes: A61B 17/025 Joint distractors
• CPC Class Codes: A61B 17/155 Cutting femur
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/30546 for adjusting elasticity, flexibility, spring rate or mechanical tension
• CPC Class Codes: A61F 2002/4658 for measuring dimensions, e.g. length
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2250/0012 for adjusting elasticity, flexibility, spring rate or mechanical tension

Abstract

A tool for preparing a bone end for prosthetic joint replacement. The tool rests on a resected end of one bone of an articulating joint set, and includes a jack assembly for supporting an opposing bone of the set in flexion while the bone ends remain attached together by ligaments. The jack pivotally supports the opposing bone and raises it to the spacing of the intended prosthesis to allow the surgeon to balance soft tissue tension. This support allows the bone to rotate under the tension of the connecting ligaments, into natural alignment while a template carried by the jack assembly lies against the prepared end, so subsequent cuts are in correct rotational alignment and the bone enjoys a natural posture when the joint components are attached. Preferably, a sizing jig in the tool contacts the bone to determine an offset, and a positioning block coupled to the sizing jig confirms the size, and positions drill holes on the bone surface contacted by the jig to set the orientation for attaching a cutting block. The sizing jig may include a template for indicating the size of a required joint component, and the jack may support the bone on an intramedullary rod. In one embodiment, the jack moves a gimballed assembly which fits about the intramedullary rod, allowing the template to rest flat against the resected bone end. Preferably, the device places drill holes in position for a cutting block to fit a femoral end component of a prosthetic knee.

Claims

1. A tool for prosthetic joint replacement surgery, such tool comprising

a jack for supporting a bone of an articulating set of bones to which a prosthetic end component is to be fastened at a respective end of said bone as it remains attached by ligaments to an opposed bone of said set, said jack including a jack assembly for raising said bone to permit the surgeon to adjust soft tissue tension in flexion, and support means raised by the jack assembly, said support means pivotally engaging and supporting said bone such that said bone rotates due to tension of said ligaments, and

a jig carried on the jack. said jig including a template for placing an aligned mark to prepare said bone for fastening the prosthetic end component

said jack cooperating with said jig to position the template while the bone has rotated into natural alignment, thereby assuring a correct rotational alignment of the bone when the prosthetic end component is attached.

2. A tool according to claim 1, wherein the jig includes a drill guide for positioning drill holes in an end surface of the bone to secure a cutting block.

3. A tool according to claim 1, wherein the jig and jack include scale markings that cooperate to indicate size of the component.

4. A tool according to claim 1, wherein the support means includes an intramedullary rod extending from the jack assembly into the bone such that the bone rotates about its longitudinal axis.

5. A tool according to claim 4, wherein the jig marks an orientation or position of a saw cut plate for fitting a femoral end component.

6. A tool according to claim 4, wherein the jack includes a gimballed assembly that engages the intramedullary rod to support the bone, and the back varies height of the gimballed assembly, thereby allowing the bone to assume a natural varus/valgus orientation.