Surgery – Instruments – Orthopedic instrumentation
Patent
1996-02-20
1998-02-17
Buiz, Michael
Surgery
Instruments
Orthopedic instrumentation
606 72, 606 60, 606 86, 606104, 606224, 606232, A61B 1758
Patent
active
057187061
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates generally to a fastener for attaching tendons to bones and in particular to a surgical screw having a washer for immobilising tendons within pre-formed 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 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 40 mm 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 one aspect the present invention consists in a surgical fastener for attaching one end of a graft tendon to a bone, the bone having a hole formed therein to receive the surgical fastener, the surgical fastener being a screw having a head, a neck and a shank with an end distal the head, the shank having a thread formed along at least a portion of its length, the head being generally hemispherical and of a diameter greater than the shank, and an annular washer being disposed about the neck of the screw intermediate the head and shank, wherein the washer is arranged such that in operation the one end of the tendon can be attached thereto and substantially immobilised between the head and the inside of the hole.
The thread in longitudinal section along the entirety of the thread is preferably devoid of an outermost cutting line. In one embodiment the screw has a shank having a thread formed along the entirety of the shank. The screw thread is preferably approximately or wholly sinusoidal in longitudinal section so as to present a soft thread devoid of an outermost cutting line.
The screw preferably has a drive socket concentric with the head and a longitudinal cannulation concentric of the shank.
In a further embodiment the annular washer is positioned adjacent the head of the screw and preferably has at least one hole in its annular portion. The washer more preferably has four holes in its annular portion, the four holes preferably confined to one half of the annular portion.
In a second aspect an annular plug made of bone is disposed about the neck of the screw between the annular washer and the head. The neck of the screw in this embodiment is preferably adapted such that the bone plug is compressed laterally when the screw is in use.
In a further embodiment the present invention comprises a method for attaching one end of a tendon to a bone, using the surgical fastener according to the first aspect of the invention, comprising the steps of: end and comprising two portions, the first portion, adjacent the first end, having a diameter larger than the diameter of the second portion, distal to the first end, such that there is formed an annular abutment in the hole; washer is positioned proximate the
REFERENCES:
patent: 4828562 (1989-05-01), Kenna
patent: 4988351 (1991-01-01), Paulos et al.
patent: 5129902 (1992-07-01), Goble et al.
patent: 5383878 (1995-01-01), Roger et al.
Buiz Michael
Hip Developments Pty. Ltd.
Shai Daphja
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