AU697490B2 - Surgical staple and washer - Google Patents

Description

AxUSTRALIA Patents Act 1990 "t 1 DvcipUut G -Ly DL T' R' 4 t i I

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ORIGINAL

COMVPLErT SPECIFICATION STAN DARD P3ATENT Invpention 7'iile: Surgical Staple and Washer The following statement is a fUll description of this invention including thle best nmethod of performing it known to us:- .1o~ 4e .1 et 4 e e

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CC.e C...o C C A~e FIELD OF THE INVENTION The present invention relates generally to a fastener for attaching tendons to bones and in particular to a surgical staple having a washer for immobilising tendons within pre-fornied holes in bone.

BACKGROUND ART It is known that damaged anterior cruciate ligaments can be repaired by grafting a portion of patellar tendon. which has been harvested with blocks of bone physiologically bound at each end, between the femur and tibia at the knee joint. The harvested blocks of bone are typically positioned in pre-drilled holes in the femur and tibia.

This method of ligament repair is often a difficult and time consuming operation with consequent concerns about patient comfort and safety. The harvesting of patellar tendon can also itself cause problems for the patient. In many patients the graft tendon is also often not in a suitable 15 physiological condition for use. It is, therefore, desirable to harvest tendon without bone attached and then position the tendon at the required site such that the bone growth fixates the tendon to the bone.

A main requirement for fixation is that the graft tendon be held securely without moving or pistoning within a bone hole.

Current methods for fixation of a tendon !include a staple, around which the tendon is positioned prior to the staple being placed within the bone. This method suffers two main disadvantages. Firstly, on the femoral side. the staple is applied to the outer surface of the femur and an extra incision is therefore required. Secondly, because fixation is outside the femur and the tendon lies in a bone tunnel of around 40am in length, the elasticity of the tendon allows pistoning under load and so healing to the bone of the tendon graft may fail or be a weak, fibrous healing that allows later loosening.

DISCLOSURE OF THE INVENTION According to a first aspect. the present invention consists in a surgical fastener, the fastener being a staple for attaching a graft tendon to a bone. the surgical staple comprising two substantially parallel legs interconnected bv a transverse head menber. each leg being of substantially the same length and having a free end portion connected substantially at a right angle to a head portion. such that the head member is laterally displaced from the free end portions and a washer disposed around the free 4 lle n IdUrIme"i-WMW C C 0 oA.

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Coe end portions proximate the substantially right angled connection with the head portions.

The surgical staple preferably has two parallel legs, each leg of the same length and having a free end portion connected at a right angle to a head portion.

The transverse head member interconnecting the two head portions is preferably ranted downwardly from the plane of the head portions.

The surgical staple is preferably comprised of one linear member folded to the required shape. The linear member is preferably a wire with the free end portions preferably having a sharp arrow tip to facilitate insertion of the staple into the bone. The portions of the wire likely to come into contact with the tendon are preferably rounded to prevent damage to the tendon. The wire is preferably a biologically inert metal, The washer is preferably oval in shape with rounded edges to prevent damage to the graft tendon. There are preferably two holes laterally displaced in the washer for each of the legs. The washer is preferably-made of a biologically inert metal, In a further aspect, the present invention comprises a method for attaching a loop of tendon to a bone using the surgical fastener according to 20 the first aspect of the invention comprising the steps of: positioning the washer through the loop of the tendon: inserting the free end portions of the staple's legs through the washer so as to position the loop of tendon within the staple: and inserting the staple into the bone such that the tendon is firmly secured to the bone both under the washer and under the laterally displaced head member, such that any tilting of the staple under load will serve to press the head member more firmly onto the tendon thereby ameliorating loosening of the tendon and staple from the bone.

The staple is preferably inserted into the bone at the required site using an appropriate hammer like tool.

BRIEF DESCRIPTION OF THE DRAWINGS By way of example only, a preferred embodiment of the invention will be described with reference to the accompanying drawing, in which; Fig is a perspective view of a surgical fastener according to the present iivention.

3 PREFERRED MODE OF CARRYING OUT THE INVENTION An embodiment of the present invention is generally shown as 60 in Fig 1.

The surgical staple 60 includes two parallel legs 61 inter-connected by a rounded transverse head member 62. Each of the legs 61 comprises a free end portion 63 and a head portion 64 connected at right angles 65, such that the head member 62 is laterally displaced from the free end portion 63 of the legs 61. The surgical staple 60 also includes a washer 66 disposed around the free end portions 63 proximate the right angles 65 in the legs 61.

The free end portions have an arrow shaped tip 67 to facilitate insertion of the staple 60 into the bone.

The washer 66 is oval in shape with rounded edges 68 to prevent damage to the tendon 26 which is looped around the washer 66.

In order to secure the tendon 26 to a bone, the staple 60 is hammered 15 into a bone. with the tendon 26 secured both at the site of the washer 66 and :the transverse head member 62.

Any loosening of the staple 60 under load serves to further press the transverse head member 62 more firmly onto the tendon 26 thereby ameliorating any loosening of the tendon 26 from the bone.

20 It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be l* considered in all respects as illustrative and not restrictive.

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Claims (10)

1. A surgical fastener, the fastener being a staple for attaching a graft tendon to a bone, the surgical staple comprising two substantially parallel legs interconnected by a transverse head member, each leg being of substantially the same length and having a free end portion connected substantially at a right angle to a head portion, such that the head member is laterally displaced from the free end portions and a washer disposed around the free end portions proximate the substantially right angled connection with the head portions.

2. The surgical fastener of claim 1 wherein the surgical staple has two parallel legs, each leg of the same length and having a free end portion connected at a right angle to a head portion.

3. The surgical fastener of claims 1 or 2 wherein the transverse head member interconnecting the two head portions is canted downwardly from the plane of the head portions.

4. The surgical fastener of any one of the preceding claims wherein the surgical staple is comprised of one linear member folded to the required shape.

The surgical fastener of claim 4 wherein the linear member is a wire 20 with the free end portions having a sharp arrow tip to facilitate insertion of the staple into the bone and the portions of the wire likely to come into contact with the tendon are rounded to prevent damage to the tendon.

6. The surgical fastener of any one of the preceding claims wherein the washer is oval in shape with rounded edges to prevent damage of the graft tendon and has two holes laterally displaced for each of the legs.

7. A method for attaching a loop of tendon to a bone using the surgical fastener according to any one of the preceding claims comprising the steps of: positioning the washer through the loop of the tendon: inserting the free end portions of the staples' legs through the washer so as to position the loop of tendon within the staple; and inserting the staple into the bone such that the tendon is firmly secured to the bone both under the washer and under the laterally displaced head member, such that any tilting of the staple under load will serve to press the head member more firmly onto the tendon thereby ameliorating loosening of the tendon and staple from the bone. I- 111-- L4P--~C'i' Lp-YrCI

8. The method of claim 7 wherein the staple is inserted into the bone at the required site using an appropriate hammer like tool.

9. A surgical fastener for attaching a graft tendon to a bone substantially as described herein with reference to Fig. 1.

10. A method for attaching a loop of tendon to a bone using the surgical fastener as described herein with reference to Fig. 1. Dated this '19th day of August 1997 V 7 -OF 1111' I1EVEIflPkmMTfl pry T.TT Patent Attorneys for the Applican t: it I h I C C C CC tic, V 4 *Stt PG C C C 4. it F.B. RICE 8& CO. ZEN.- I I k- iI ABSTRACT A surgical staple for attaching a graft tendon to a bone. The staple comprises two legs interconnected by a head member, with each leg comprising a free end portion connected substantially at a right angle to a head portion such that the head member is laterally disposed from the free end portions. The fastener also includes a washer which is adapted to be disposed around their free end portions proximate the right angled connections with the respective head portions. *4*0 4 a 0 44 0 44 4 ~a 04 4a 4 4 9 0 4800 044) 4( 04 44 4d 4 41 4 0r a