WO2012136972A1 - A surgical drive tool - Google Patents

A surgical drive tool Download PDF

Info

Publication number
WO2012136972A1
WO2012136972A1 PCT/GB2012/050318 GB2012050318W WO2012136972A1 WO 2012136972 A1 WO2012136972 A1 WO 2012136972A1 GB 2012050318 W GB2012050318 W GB 2012050318W WO 2012136972 A1 WO2012136972 A1 WO 2012136972A1
Authority
WO
WIPO (PCT)
Prior art keywords
drive
drive shaft
portion
head
sleeve
Prior art date
Application number
PCT/GB2012/050318
Other languages
French (fr)
Inventor
Tim BIRD
Original Assignee
Finsbury (Development) Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to GB1105932.6 priority Critical
Priority to GBGB1105932.6A priority patent/GB201105932D0/en
Application filed by Finsbury (Development) Ltd filed Critical Finsbury (Development) Ltd
Publication of WO2012136972A1 publication Critical patent/WO2012136972A1/en

Links

Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/16Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans
    • A61B17/1613Component parts
    • A61B17/162Chucks or tool parts which are to be held in a chuck
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/16Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans
    • A61B17/1659Surgical rasps, files, planes, or scrapers
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00Surgical instruments, devices or methods, e.g. tourniquets
    • A61B17/16Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans
    • A61B17/1662Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans for particular parts of the body
    • A61B17/1664Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans for particular parts of the body for the hip
    • A61B17/1666Bone cutting, breaking or removal means other than saws, e.g. Osteoclasts; Drills or chisels for bones; Trepans for particular parts of the body for the hip for the acetabulum

Abstract

A surgical drive tool and method of coupling of a rotational driver to a surgical instrument are described. The tool includes a drive shaft having a first end arranged to couple to a rotational driver. A drive head is coupled to- a second end of the drive shaft. A first portion of the drive head does not extend outside of a predetermined shape surrounding the drive shaft axis and incorporates a drive head slot. A drive dog is coupled to the drive shaft and is arranged to slide relative to the drive shaft to engage the drive head slot. The combination of the first portion and the drive dog extends outside of the predetermined shape. The drive dog is arranged to retract from the drive head slot to allow the first portion to be inserted through an orifice defined by the predetermined shape in a surgical instrument. The drive head is arranged to rotate within the orifice such that the first portion cannot be retracted from the orifice and such that the drive dog can engage the drive head slot through the orifice to limit further rotational movement between the drive tool and the orifice.

Description

A Surgical Drive Tool

The present invention relates to a surgical drive tool. In particular, embodiments of the present invention relate to a surgical drive tool for coupling a rotational driver such as a drill to a reamer to provide rotational drive to the reamer.

An acetabular reamer is a surgical instrument for cutting a socket into a patient's acetabulum to receive an acetabular cup forming the socket part of a hip joint prosthesis. An acetabular reamer typically comprises a cutting cup, which is generally hemispherical to conform to the shape of the acetabular cup, and a backing plate incorporating a drive coupling feature to connect the reamer to a drive tool. The drive tool in turn is coupled to portable drill or other rotational driver to provide rotational drive to the cutting cup. The cutting cup incorporates a plurality of cutting edges which engage the bone and remove portions of the bone so as to form a bone socket generally in the shape of the cutting cup. Bone fragments may pass through openings associated with each cutting edge to collect within the cutting cup.

Known surgical drive tools suitable for driving acetabular reamers provide coupling features that include bayonet connectors and plug and socket connectors. One particular known coupling mechanism comprises a pin arranged to pass through an orifice in a backing plate of a reamer and a flange arranged to bear against the backing plate surrounding the orifice. The pin supports a spring loaded retaining mechanism arranged to pass through the orifice and engage the inside of the reamer surrounding the orifice to draw the reamer towards the flange. Such a mechanism may be difficult to clean. Additionally, it may be difficult to manufacture such a mechanism with sufficient accuracy to prevent play between the two parts.

An acetabular reamer may be a single use surgical instrument to be disposed of after it has been uses to cut a single bone socket. It is desirable to be able to readily engage and disengage the reamer on the drive tool. Alternatively, it may be necessary to be able to remove an acetabular reamer from a drive tool in order to be able to clean or maintain the reamer. At the same time, it is important to ensure that the drive tool securely engages the reamer to prevent misalignment of the bone socket, or damage to the drive tool or reamer.

It may be the case that a reamer is arranged to be driven in only a single rotational direction. However, for certain reamers it may be that the reamer can be driven in both directions. Consequently it is desirable that a drive tool is capable of coupling to a reamer such that the reamer can be driven in both directions without the reamer detaching from the drive tool. It is a further requirement of all reusable surgical instruments, including drive tools, that they are easy to clean. While acetabular reamers may be inexpensive, disposable items, typically drive tools are more complex and expensive and so must be reused.

It is an object of embodiments of the present invention to obviate or mitigate one or more of the problems associated with the prior art, whether identified herein or elsewhere. In particular, it is an object of embodiments of the present invention to provide an improved surgical instrument drive tool that is simple and quick to couple to surgical instruments, capable of driving a surgical instrument in both rotational directions and is relatively easy to clean. According to a first aspect of the present invention there is provided a surgical drive tool comprising: a drive shaft having a first end arranged to couple to a rotational driver; a drive head coupled to a second end of the drive shaft, a first portion of the drive head not extending outside of a predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis, the first portion of the drive head incorporating a drive head slot; and a drive dog coupled to the drive shaft and arranged to slide relative to the drive shaft to engage the drive head slot such that the combination of the first portion of the drive head and the drive dog extends outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis; wherein the drive dog is arranged to retract from the drive head slot to allow the first portion of the drive head to be inserted through an orifice defined by the predetermined shape in a surgical instrument, the drive head being arranged to rotate within the orifice such that the first portion of the drive head cannot be retracted from the orifice and such that the drive dog can engage the drive head slot through the orifice to limit further rotational movement between the drive tool and the orifice.

An advantage of the first aspect of the present invention is that because the drive dog engages the drive head slot through the orifice, the drive dog bears against the edge of the orifice limiting further rotational movement between the drive head and the surgical instrument. This allows the surgical instrument to be driven in both rotational directions. Additionally, in certain embodiments the drive dog is resiliently biased towards the drive head such that the drive dog can automatically retract as the drive head is inserted into the orifice and then automatically engage the drive head slot as the drive head is rotated within the orifice. This simplifies the process of coupling the drive tool to the surgical instrument as it is necessary only to push the drive head into the orifice and then rotate the drive tool relative to the surgical instrument until the drive dog automatically engages the drive head slot through the orifice.

The first portion of the drive head may comprise at least two spaced apart slots and the surgical drive tool may comprise at least two drive dogs arranged to engage the drive head slots, said at least two drive dogs extending towards the drive head from a drive sleeve arranged to slide along the drive shaft.

The surgical drive tool may further comprise a resilient element extending between the drive sleeve and a portion of the drive shaft, the resilient element being arranged to bias the drive sleeve towards the drive head such that the drive dogs are biased towards a position in which they engage the drive head slots. The resilient element may comprise a spring extending between the drive sleeve and a portion of the drive shaft.

The drive sleeve may comprise a longitudinal channel arranged to pass over a portion of the drive shaft such that the drive sleeve partially surrounds the drive shaft. The surgical drive tool may further comprise a spring bearing mounted on the drive shaft and arranged to slide along the drive shaft, the spring extending between the drive shaft thrust face and the spring bearing, the spring bearing being arranged to engage an internal thrust face within the drive sleeve channel. The spring bearing may comprise a non-circular aperture arranged to slide along a corresponding non-circular spring bearing guide portion of the drive shaft such that rotation of the spring bearing about the drive shaft is limited, the spring bearing being further arranged to engage the sides of the drive sleeve channel to limit rotation of the drive sleeve relative to the spring bearing. The drive sleeve, the spring bearing and the spring bearing guide portion of the drive shaft may be arranged such that when the drive dogs are engaged in the drive head slots the spring bearing slides along the spring bearing guide portion of the drive shaft causing rotation of the drive sleeve about the drive shaft to be limited.

The drive shaft may further comprise a groove having a maximum width less than the minimum width of the spring bearing aperture in a plane perpendicular to the drive shaft axis and a length along the drive shaft axis sufficient to accommodate the spring bearing, the groove being positioned along the drive shaft such that when the drive dogs disengage the drive head slots the spring bearing is arranged to engage the groove allowing the spring bearing and the drive sleeve to rotate about the longitudinal axis of the drive shaft.

The drive shaft may further comprise a locking portion which is non circular in cross section such that in a first radial direction about the drive shaft axis the locking portion has a first width which is narrower than the width of the mouth of the drive sleeve channel, and in a second radial direction the locking portion has a second width which is larger than the width of the mouth of the drive sleeve channel but smaller than the diameter of a body portion of the channel such that the locking portion can rotate within the body portion of the channel.

When the drive sleeve is mounted on the drive shaft and the spring bearing is positioned on the spring bearing guide portion of the drive shaft the second width of the drive shaft locking portion may be aligned with the mouth of the drive shaft channel such that the drive sleeve channel cannot pass over the drive shaft locking portion. The predetermined shape has at least twofold rotational symmetry. The predetermined shape may have three sides. The first portion of the drive head may comprise three spaced apart slots arranged to be engaged by three drive dogs with one slot positioned on each side of the predetermined shape. The predetermined shape may be defined by three arcs extending between inner and outer circles centred on the drive shaft axis, the arcs being tangential to the inner circle at three spaced apart points and tangential to the outer circle at three spaced apart points intermediate the three spaced apart points on the inner circle.

Collectively, at least the portion of the drive dogs arranged to engage the slots may not extend outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis.

According to a second aspect of the present invention there is provided a surgical drive tool as described above, wherein the drive head further comprises: a flange positioned between the drive head first portion and the drive shaft, the flange extending outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis so as to limit insertion of the drive head into an orifice defined by the

predetermined shape in a surgical instrument, the drive head slots extending through the flange; and a groove between the drive head first portion and the flange, the maximum width of the drive head within the groove being less than the minimum width of the drive head first portion perpendicular to the drive shaft axis.

The surgical drive tool may further comprise an outer sleeve arranged to extend around at least part of the drive shaft and to rotate about the drive shaft, the outer sleeve

incorporating a first feature arranged to engage the drive sleeve as it slides along the drive shaft to limit the extent of sliding movement of the drive sleeve along the drive shaft such that the drive dogs do not disengage the drive head slots.

According to a third aspect of the present invention there is provided a surgical instrument set comprising: a surgical drive tool as described above; a rotational driver arranged to couple to the first end of the surgical drive tool to impart rotational drive to the surgical drive tool; and a surgical instrument incorporating an orifice defined by the predetermined shape and arranged to be engaged by the drive head such that the surgical drive tool can impart rotational drive to the surgical instrument.

The surgical instrument may be a reamer comprising a reaming body incorporating cutting edges arranged to remove portions of bone and a coupling portion incorporating the orifice.

According to a fourth aspect of the present invention there is provided a method of coupling a rotational driver to a surgical instrument, the method comprising; coupling a rotational driver to a first end of a drive shaft part of a surgical drive tool such that the rotational driver can impart rotational drive to the surgical drive tool; inserting a first portion of a drive head coupled to a second end of the drive shaft through an orifice in a surgical instrument, the drive head first portion not extending outside of a predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis, and the predetermined shape defining the shape of the orifice; rotating the drive head first portion such that the first portion of the drive head cannot be retracted from the orifice; sliding a drive dog coupled to the drive shaft towards the drive head such that the drive dog can engage a slot in the first portion of the drive head slot through the orifice to limit further rotational movement between the drive tool and the orifice, the combination of the first portion of the drive head and the drive dog extending outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis to prevent the drive head being withdrawn through the orifice.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of a drive tool in accordance with an embodiment of the present invention;

Figure 2 is a perspective view of the drive tool of figure 1 with the drive shaft safety sleeve and the safety clip removed;

Figure 3 is an exploded view of portions of the drive tool of figure 1 ; Figure 4 is a perspective view of a drive shaft safety sleeve forming part of the drive tool of figure 1 ;

Figure 5 is a perspective view of a drive sleeve forming part of the drive tool of figure 1 from a reverse angle compared to the exploded view of figure 3;

Figure 6 is a perspective view of the drive tool of figure 1 with the drive shaft safety sleeve and the safety clip removed and with the drive sleeve retracted from the drive head;

Figure 7 is a perspective view of the drive tool of figure 1 with the drive shaft safety sleeve and the safety clip removed and with the drive sleeve retracted from the drive head and rotated part way through the process of disassembling the drive tool;

Figure 8 is a perspective view of an acetabular reamer arranged to be driven by the drive tool of figure 1 ;

Figure 9 is a cross sectional view of the drive tool of figure 1 coupled to the acetabular reamer of figure 8;

Figure 10 is a view from the second end of the drive tool of figure 1 coupled to the acetabular reamer of figure 8 with the cutting cup removed; and

Figure 1 1 illustrates in greater detail the shape of the orifice in the reamer of figure 8.

Referring first to figure 1, this illustrates a surgical drive tool in accordance with an embodiment of the present invention suitable for coupling to an acetabular reamer. The drive tool comprises a drive shaft 2 (only part of which is visible in figure 1 ) arranged to transfer rotational drive to a drive head 4 coupled to a second end of the drive shaft 2. The first end of the drive shaft 2 comprises a drive coupler 6 arranged to coupled the drive tool to a rotational driver such as a portable drill (not illustrated). The drive coupler 6 may be entirely conventional, for instance comprising a non-circular portion as illustrated to allow torque to be transferred to the drive tool, and so will not be further described here. The drive shaft 2 and drive head 4 may be formed from a metal so as to provide a high strength component for transferring torque. The drive head 4 is rigidly coupled to the second end of the drive shaft 2, for instance by welding, so that the drive shaft 2 directly transfers torque from the rotational driver to the drive head 4.

The drive tool further comprises a drive shaft safety sleeve 8 which surrounds the majority of the length of the drive shaft 2. The shaft safety sleeve 8 is illustrated removed from the drive tool in figure 4. The shaft safety sleeve 8 may be formed from a plastic material and is loosely coupled to the drive shaft 2 so that the drive shaft 2 can rotate within the shaft safety sleeve 8 while the shaft safety sleeve 8 is held by a surgeon during reaming. The shaft safety sleeve 8 comprises a first section 10 of generally uniform internal diameter arranged to be slightly larger than the corresponding portion of the drive shaft 2 to allow for free rotation. The shaft safety sleeve 8 further comprises a second section 12 having an enlarged internal diameter arranged to surround additional components of the drive tool, with a tapered transition between the first and second sections 10, 12.

The drive shaft 2 further comprises a first stop portion 14 having an increased diameter which exceeds the internal diameter of the first section 10 of the shaft safety sleeve 8 such that the shaft safety sleeve 8 cannot slip from the drive shaft 2. However, to permit the shaft safety sleeve 8 to be removed for cleaning and maintenance the sleeve 8 comprises a continuous longitudinal split 16 along a first side and an opposite longitudinal split 18 though the larger second section 12. The longitudinal splits 16, 18 allow the shaft safety sleeve 8 to be deformed such that it can pass over the first stop portion 14 for removal.

Referring now also to figure 2, this illustrates the drive tool of figure 1 with the drive shaft safety sleeve 8 removed such that further details of the drive tool are visible. The majority of the drive shaft 2 is visible showing a constant diameter portion 20 arranged to rotate within the first portion 10 of the shaft safety sleeve 8 and the first stop portion 14. The drive shaft 2 further comprises a second stop portion 22 in the form of a tapering flange which corresponds to the internal form of the shaft safety sleeve 8 at the transition between the first section 10 and the second section 12. Together the first and second drive shaft stop portions 14, 22 serve to retain the shaft safety sleeve 8 in position upon the drive shaft 2 such that in use the drive tool may be manipulated by a surgeon holding the shaft safety sleeve 8 leaving the surgeon with a free hand to control the rotational driver. Figure 2 illustrates further parts of the drive tool. A drive sleeve 24 partially surrounds the drive shaft 2. The drive sleeve 24 is also illustrated removed from the drive shaft 2 in figure 5. The drive sleeve 24 is illustrated removed from the drive tool in figure 5. The drive sleeve 24 is arranged to engage the drive head 2 so as to lock the drive head 4 to a reamer or other surgical instrument as will be described in greater detail below in connection with figure 9. The drive sleeve 24 has an open channel on one side so as to allow its removal from the drive shaft 2, as will be described below in connection with figure 7. The drive sleeve 24 is resiliency biased towards the drive head 4 by a

compression spring 26. The compression spring 26 extends between a thrust face 28 formed upon the drive shaft 2 and a spring bearing 30 which can slide along the drive shaft 2. The spring bearing 30 transfers spring force from spring 26 to the drive sleeve 24.

Referring now to figure 3 this illustrates in an exploded view the majority of the components of the drive tool of figure 1 , except for the drive shaft safety sleeve 8, so that their structure can be more clearly seen. When manufacturing the drive tool the compression spring 26 and spring bearing 30 are passed over the second end of the drive shaft 2 until the spring 26 bears against thrust face 28. Spring bearing 30 comprises an aperture 32 which is generally circular with flats 34 which reduce the width of the aperture 32. The shape of the aperture 32 corresponds to the cross sectional shape of a spring bearing guide section 36 of the drive shaft 2 which has corresponding flats 37.

Consequently, spring bearing 30 is only able to slide over the spring bearing guide section 36 when the spring bearing 30 is rotated to align flats 34 with the flats of spring bearing guide section 36. Spring bearing 30 further comprises a raised flag 38, the purpose of which will be explained below. Correct operation of the drive tool requires that the flag 38 is correctly orientated relative to the drive head 4. It will be understood that the spring bearing 30 can slide along spring bearing guide section 36 such that the flag 38 extends in one of two directions. In alternative embodiments of the present invention the shape of the spring bearing aperture 32 and the spring bearing guide portion 36 may be chosen such that the aperture 32 can only pass over the guide portion 36 when orientated in a single direction by ensuring that the aperture 32 and the guide portion 36 are not rotationally symmetrical.

Drive shaft 2 further comprises an annular groove 40, the maximum diameter of which is less than or equal to the distance between flats 34 of the spring bearing aperture 32 and the width of which is greater than or equal to the thickness of the spring bearing 3 .

Consequently, by compressing the spring 26, the spring bearing 30 is able to slide over the spring bearing guide section 36 until it reaches the annular groove 40, whereupon the spring bearing 30 may be rotated until the flats 34 are misaligned with flats 37 trapping the spring bearing 30 within the groove 40. Further movement of the spring bearing 30 towards the drive shaft second stop portion 22 is prevented by an enlargement of the drive shaft 2 over which the spring bearing aperture 32 cannot pass.

The drive head 4 is shown detached from the drive shaft 2 in figure 2. With the spring bearing 30 engaged in groove 40 and the spring 26 spaced away from the second end of the drive shaft 2 as described above the drive head 4 may be attached to the second end of the drive shaft 2. Figure 2 illustrates the drive head 4 having a hole 42 arranged to receive a pin 44 at the second end of the drive shaft 2. The pin 44 can be welded in position within the hole 42 when the drive head 4 is correctly rotated. It will be appreciated that alternative techniques for joining the drive head 4 to the drive shaft 2 will be well known to the appropriately skilled person. With the drive head 4 coupled to the drive shaft 2 the spring 26 and the spring bearing 30 are captured upon the drive shaft 2 and cannot be removed without destruction of the drive tool.

The drive head 4 will now be described in further detail. The drive head 4 comprises a first portion 46 and a flange 48. The first portion 46 is shaped such that no part extends in a plane perpendicular to the longitudinal axis of the drive shaft 2 outside of a

predetermined shape surrounding the longitudinal axis. The predetermined shape corresponds to a shape of an aperture 50 within a backing plate 52 of an acetabular reamer 54 as illustrated in figures 8 and 9. Consequently the first portion 46 can pass through the aperture 50. At least part of the flange 48 extends beyond the predetermined shape in a plane perpendicular to the longitudinal axis of the drive shaft 2 such that the flange 48 limits the extent of insertion of the drive head 4 into the aperture 50. It will be appreciated that in alternative embodiments there may be no flange 48 and insertion of the drive head 4 into an orifice 50 may be limited by an internal structure within the reamer 54. Between the first portion 46 of the drive head 4 and the flange 48 there is a groove 56. The width of the groove 56 is larger than the thickness of the backing plate 52 of an acetabular reamer 54. The maximum diameter of drive head 4 within the groove 56 is less than the minimum width of aperture 50. The result is that the drive head 4 is able to rotate within the aperture 50 such that for at least part of the rotation the backing plate 52 surrounding the aperture 50 is captured between the drive head first portion 46 and the flange 48 as illustrated in the cross sectional view of figure 9.

The shape of the drive head first portion 46 and a locking mechanism for securing the drive head 4 to the acetabular reamer 54 will now be described. With reference to figure 8, the aperture 50 is generally triangular, though the sides are curved and the corners are rounded. More specifically, the predetermined shape is generally that of a Reuleaux triangle with rounded corners, though it is not a perfect form of a Reuleaux triangle. Figure 1 1 schematically illustrates the form of the predetermined shape 1 10. It can be seen that the predetermined shape 1 10 extends between first and second circles 1 12, 1 14. The predetermined shape 1 10 is forms from three arcs of the same shape, each extending 120° about the origin of circles 1 12, 1 14 and tangential to the circles 1 12, 1 14. It will be appreciated that in alternative embodiments the predetermined shape may vary

significantly. Viewed end on, the largest part of the drive head first portion 46 is generally the same shape. The flange 48 in contrast is generally circular and approximately equals the diameter of the largest other portions of the drive tool. The rounded comers and sides of the predetermined shape provide some degree of self alignment as the drive head first portion 46 is inserted into the aperture 50. Furthermore, as is clear from the perspective view of figure 3, the drive head first portion 46 tapers inwardly towards the end of the drive tool and the corners form smoothed noses, again to help with self alignment. Owing to the three sided shape of the drive head first portion 46, the drive head 4 may

alternatively be referred to as a tri-lobe end of the drive tool. Slots 58 are formed in the outer periphery of the drive head first portion 46 and the flange 48. The slots 58 are located mid way along each side of the drive head first portion 46. The slots 58 are arranged to receive drive dogs 60 which extend from the drive sleeve 24, as will now be described. The drive sleeve 24 is illustrated in two alternative perspective views in figures 3 and 5. The drive sleeve 24 is seated about the drive shaft 2 between the second stop portion 22 and the drive head 4. The drive sleeve 24 is generally U- shaped and can be detached from the drive shaft 2, as will be described below. In normal use however the drive sleeve 24 is coupled to the drive shaft 2 as shown in figure 2 and can slide along the drive shaft 2 without rotation. The drive sleeve 24 incorporates an internal thrust face 62 arranged to be engaged by the spring bearing 30 so as to transfer spring force from spring 26 to the drive sleeve 24 to bias the drive sleeve 24 towards the drive head 4.

The drive dogs 60 extend from the drive sleeve 24 towards the drive head 4 and are formed as lugs with a generally oval cross section. The drive dogs 60 correspond to the position and shape of the drive head slots 58 such that when drive sleeve 24 is released and free to slide the drive dogs 60 extend under the action of spring 26 through the slots 58 in flange 48 and part way into slots 58 in the drive head first part 46 as illustrated in figures 1 and 2. The drive dogs 60 may be retracted from slots 58 by manipulating the drive sleeve 24 to overcome the spring force as illustrated in figure 6. When the drive tool is fully assembled as illustrated in figure 1 an end 64 of the enlarged portion 12 of the shaft safety sleeve 8 is arranged to bear against a first rim portion 66 of the drive sleeve 24 so as to limit the extent to which the drive sleeve 24 can be retracted from the drive head 4 such that the drive dogs 60 do not fully retract from the slots 58 in the flange 48. This prevents the drive sleeve 24 from retracting far enough along the drive shaft 2 to push the spring bearing 30 into alignment with groove 40. Consequently, spring bearing 30 cannot rotate and in turn prevents the drive sleeve 24 from rotating, which prevents the drive sleeve 24 from detaching from the drive shaft, as will be described below.

When the drive dogs 60 are fully extended into the drive head 4 the drive dogs extend across groove 56 and overlap the drive head first portion 46. Further movement of the drive sleeve 24 towards the second end of the drive shaft 2 is limited by flange 48 which bears against a second rim portion 68 of the drive sleeve 24. The drive dogs 60 extend from the second rim portion 68. When viewed from the second end of the drive tool, outer parts of the drive dogs 60 engaged in the drive head slots 58 extend beyond the

predetermined shape about the drive shaft axis (the predetermined shape corresponding to the shape of the aperture 50 in an acetabular reamer 54). However, considered in isolation, the drive dogs 60 do not extend beyond the limits of the same predetermined shape when the shape is rotated relative to the drive had 4 about the longitudinal axis of the drive shaft 2. When the drive head first portion 46 is inserted into reamer aperture 5Qthe outer edges of the aperture 50 bear against the drive dogs 60 and cause the drive sleeve 24 to be push back against spring 26 until the flange 48 contacts the outside of the aperture 50. At this point the drive head 4 can be rotated within the aperture such that the edge of aperture 50 engages groove 56.

After the drive head 4 has been rotated 30° within the aperture 50 the drive dogs 60 are able to pass through the aperture 50. That is, because the drive dogs 60 are located centrally upon each side of the three sided drive head first portion 46, rotating the drive head 30° causes the drive dogs 60 to be aligned with the corners of aperture 50. The drive dogs 60 pass through the aperture 50 under the action of spring 26 until the second rim portion 68 of drive sleeve 24 contacts flange 48. Figure 9 illustrates one such drive dog 60 extending through aperture 50. Additionally, figure 10 illustrates the second end of the drive tool when coupled to a backing plate 52 of a reamer 54 (with the cutting cup 94 removed so that the second end of the drive tool can be seen). It can be seen that the corners of the drive head first portion 46 overlap the edges of the sides of orifice 50 while the drive dogs 60 engage the corners of the orifice 50. The drive dogs 60 prevent further relative rotational movement between the drive head 4 and the reamer 54. That is, the drive dogs 60 transfer torque from the drive tool to the reamer 54. The drive dogs 60 allow the reamer 54 to be driven by a rotational driver such as a power drill in either direction. To release the reamer 54 from the drive tool the drive sleeve 24 is manually retracted towards the drive shaft second stop portion 22 against the action of spring 26 until the drive dogs retract from the drive head first portion 46 and the groove 56 and optionally until the end 64 of the shaft safety sleeve 8 bears against the first rim portion 66 of the drive sleeve 24 preventing further movement of the drive sleeve 24. The drive head 4 can then be freely rotated within the aperture 50 until the drive head first portion 46 is aligned with the aperture 50 and can be removed.

The structure of the drive sleeve 24 will now be described in greater detail. As noted above, in normal use the drive sleeve 24 is arranged to slide along the drive shaft 2 without rotation and biased towards the drive head 4 by the action of spring 26. Normal use is considered to be sliding movement of the drive sleeve 24 limited in a first direction by first rim portion 66 contacting the end 64 of the shaft safety sleeve 8 and limited in a second direction by second rim portion 68 contacting drive head flange 48. Within this extent of motion the drive dogs 60 do not fully retract from the portion of slots 58 extending through flange 48, which consequently acts as a first limit on rotation of the drive sleeve 24. A further limit on rotation of the drive sleeve comes about from interaction with the spring bearing 30. As noted above, spring 26 forces spring bearing 30 into contact with internal thrust face 62 of the drive sleeve 24. Spring bearing flag 38 extends upwards through open channel 70 which runs along the length of the drive sleeve 24. A first part of channel 70 running from internal thrust face 62 away from the drive dogs 60 is defined by parallel faces 72 which are spaced apart by the width of flag 38. Consequently flag 38 bears against parallel faces 72. As noted above, the spring bearing 30 slides along spring bearing guide 36 and is prevented from rotating by flats 34. Consequently, this inability to rotate is transferred to drive sleeve 24 by flag 38.

Drive shaft 2 further comprises a locking portion 74 in the form of a flange or increased diameter portion, the start of which provides spring thrust face 28. Drive shaft locking portion 74 is cylindrical but with flats 76. Drive sleeve 24 further comprises a series of differing diameter channel portions, the largest channel portion 78 being generally cylindrical and of just larger diameter than the greatest width of drive shaft portion 74 and larger in diameter than its mouth between flats 72. Channel portion 78 is arranged to slide over drive shaft locking portion 74 which serves to keep drive sleeve 24 aligned with the longitudinal axis of the drive shaft 2. Similarly, the internal thrust face 62 which engages the spring bearing 30 is slightly cupped in order to prevent radial movement of the drive sleeve 24 relative to the longitudinal axis of the drive shaft 2. Furthermore, the drive dogs 60 bear against the edges of slots 58 within drive head flange 48 preventing radial movement of the drive sleeve 24.

The distance between flats 76 is just smaller than the distance between parallel faces 72 defining the mouth of the drive sleeve channel portion 78. Consequently during disassembly of the drive tool rotating drive sleeve 24 until faces 72 are aligned with flats 76 releases the drive shaft portion 74 from channel 78. As discussed above, this rotation is not possible until the drive dogs 60 have retracted from the slots 58 in flange 48 and the spring bearing 30 is aligned with the drive shaft groove 40.

A second drive sleeve channel portion 80 extends from the second rim portion 68 to the internal thrust face 62. The second channel portion 80 is generally U shaped and the distance between faces 82 defining the mouth of channel portion 80 is equal to or greater than the largest diameter of the spring bearing guide portion 36. The second channel portion 80 is narrower than the first channel portion 78. The base of channel 80 is defined by a curve of equal or larger radius than the curved part of spring bearing guide 36. The second channel portion 80 is arranged to pass over the spring bearing guide portion 36 and allow the spring bearing guide portion 36 to freely rotate within the second channel portion 80.

A third channel portion 84 is positioned between the first and second channel portions 78, 80. The third channel 84 is generally U shaped and is defined by faces 72. The base of channel 84 corresponds to the shape of the lower part of the spring bearing 30 and the channel 84 is arranged to freely slide over the spring bearing 30. The third channel 84 is of intermediate width between the first and second channel portions 78, 80. The boundary between the second and third channels 80, 84 is defined by internal thrust face 62, which represents a step increase in size of the U shaped channels. The boundary between the first and third channel portions 78, 84 is defined by a stop face 86. The first channel portion 78 essentially is a continuation of the third channel portion 84 in which the U shaped third channel 84 has been enlarged to form a cylindrical part which has a diameter larger than the distance between faces 72 at the mouth of the first channel portion 78. When the drive sleeve 24 is coupled to the drive shaft 2 and in its normal operating sliding range a safety clip 88 may be coupled to the drive sleeve seated in a groove 90 lying between the first and second rim portions 66, 68 of the drive sleeve 24. The safety clip 88 reduces the risk of injury to a surgeon holding the drive tool by reducing the risk of inserting a finger into the channel 70 as. it is rotating at high speed. The clip 88 is generally C shaped and formed from a plastic material so that it can deform to pass over the drive sleeve 24 between the rim portions 66, 68. To ensure that the safety clip 88 does not spin round to open up the channel 70 twin lugs 92 extend from either side of the clip and are arranged to seat within the drive sleeve channel 70. Clip 88 is shown secured to the drive sleeve 24 in figure 1. The safety clip 88 also serves to cover over channel 70 between the rim portions 66, 68 to reduce the amount of bone and other debris that may accumulate in channel 70 during surgical use. Much of the remainder of channel 70 extending from the first rim portion 60 is covered over by the shaft safety sleeve 8. Reamer 54 illustrated in figure 8 comprises a backing plate 52 incorporating an orifice 50 which is substantially the same shape as the first portion 46 of the drive head 4 (ignoring the slots 58). The reamer 54 further comprises a cutting cup 94. The cutting cup 94 is generally hemispherical with a hemisphere part 96 but also has a parallel portion 98 as illustrated in figure 9 where the cutting cup 94 couples to the backing plate 52. Similarly, the backing plate 52 comprises a cylindrical rim part 100 which can be joined to parallel portion 98 of the cutting cup 94 for instance by welding or adhesive or any other known technique. Cutting cup 94 comprises a plurality of holes 102, each having a raised edge (not illustrated) to form a cutting edge. The use of thin metal sheet to form the cutting cup 94 means that sharpening of the edges may not be required, especially taking into account that the reamer 54 is a single use item. The raised edges may be in the form of a spherical deformation of the cutting cup on the trailing edge of the holes 102 with regard to the normal direction of motion. The holes 102 may be arranged in a spiral pattern starting from the pole of the cup 94. The spiral pattern may be a twin start spiral, for instance with the spirals extending generally parallel to one another. The pattern may vary. One hole, or a small cluster of holes, may be provided at the pole of the cutting cup 94 to initiate the cutting action to enable a plunge. The process of coupling the drive tool to a reamer will now be described. As discussed above, the drive head first portion 46 is capable of a certain amount of self alignment with a reamer aperture 50 owing to its generally tapered shape and smoothly curved corners. To align the drive head first portion 46 with the aperture 50 requires a maximum rotation of 60° in either direction as the drive head 4 and aperture 50 have threefold rotational symmetry. Once aligned, pushing the drive head first portion 46 into the aperture 50 applies force to the drive dogs 60 which contact the edge of the aperture 50. If the force applied to the drive dogs 60 exceeds the spring force provided by spring 26 then the drive dogs 60 retract until the drive head flange 48 contacts the reamer backing plate 52 surrounding the aperture 50. Once the backing plate 52 is aligned with drive head groove 56 it is possible to rotate the drive head 4 relative to the reamer 54.

The diameter of the drive head 4 at the groove 60 is less than or equal to the minimum width of the aperture 50. If the drive sleeve 24 is manually retracted then the drive head 4 may be freely rotated. However, if the drive sleeve 24 is left to act under the force of spring 26 then after a rotation of 60° in either direction the drive dogs 60 align with the corners of the aperture 50 and snap into engagement passing through the aperture 50 to extend across drive head groove 56. The tips of drive dogs 60 may be rounded to ease their passage between the edge of the aperture 50 and the drive head 4. Bi-directional drive off the reamer 54 is possible as the drive dogs 60 are located in the corners of the aperture 50 and each drive dog 60 bears against a pair of sides of the aperture 50. The reamer 54 is positively engaged to the drive tool. The automatic deployment of the drive dogs 60 under the action of spring 26 allows the reamer 54 to be coupled to the drive tool by a surgeon holding the reamer 54 in one hand and either the drive tool safety sleeve 8 or a portable drill coupled to the drive tool in the other hand. If the surgeon is holding the shaft safety sleeve 8 then the sleeve is free to rotate about the drive shaft 2. However, the axial force applied to the drive shaft by the reamer 54 causes the an internal chamfer within the shaft safety sleeve 8 at the junction between the first and second portions 10, 12 bears against the chamfered second stop portion 22 on the drive shaft 2 to provide sufficient frictional engagement to rotate the drive head 4 within the aperture 50. This allows one handed actuation of the spring loaded drive dogs mechanism and to rotate the drive head for engaging and disengaging a reamer. To disengage the reamer 54, a surgeon holding the shaft safety sleeve 8 can retract the drive sleeve 24 using a finger and thumb of the same hand until the sleeve end 64 contacts the first drive sleeve rim portion 66. This retracts the drive dogs 60 from the aperture 50 allowing the reamer 54 to be rotated with the surgeons other hand by 60° in either direction until the drive head first portion 46 is released from the aperture 50.

The process of assembling the drive tool will now be described. As noted above, the spring 26 and spring bearing 30 must be coupled to the drive shaft 2 before the drive head 4 is welded to the second end of the drive shaft 2. The spring bearing 30 has a cylindrical portion 104 which faces the drive head 4 and is arranged to be received in the cupped portion 106 of the drive sleeve 24. The drive head 4 is attached such that one corner of the drive head first portion 46 is aligned with one of the curved sides of the spring bearing guide portion 36 of the drive shaft.

It can be seen that flats 37 of the spring bearing guide portion 36 are not rotationally aligned with flats 76 of the increased diameter portion or flange 74. This is important to ensure that the drive sleeve 24 cannot be detached from the drive shaft 2 during normal use without rotation. Flats 37 are illustrated as being 90° out of alignment with flats 76, though it will be understood that a different amount of misalignment may be provided.

The spring bearing 30 is arranged to slide along the drive shaft 2 until it is aligned with groove 40. It may then be rotated to lock the spring 26 in compression and to align the spring bearing outer flats 108 with flats 76 on the drive shaft 2. The drive sleeve 24 can then be mated with the drive shaft 2 by passing channel 70 over the spring bearing 30 and the drive shaft locking portion 74 such that drive sleeve faces 72 slide over spring bearing flats 108 and drive shaft locking portion flats 76 until the cylindrical portion 104 of spring bearing 30 can engage the cupped portion 106 of thrust face 62 within the drive sleeve 24. This step is illustrated in figure 7. Spring bearing flag 38 must face out of channel 70 for this engagement to be possible. It can be seen in figure 2 that the curved top edge of flag 38 follows the same radius as the outer part of the drive sleeve 24 when assembled, though this is not essential. Rotating the drive sleeve 24 relative to the drive shaft 2 causes the curved part of enlarged drive shaft portion 74 to engage the sides of the drive sleeve first channel portion 78. Rotation of the drive sleeve 24 also drives rotation of the spring bearing 30 through flag 38 until spring bearing flats 34 are aligned with the spring bearing guide portion flats 37. This alignment releases the compressed spring 26 driving the drive sleeve 24 into engagement with the drive head 4. It will be appreciated that there are two possible directions of rotation that will release spring bearing 30 from drive shaft groove 40,. only one of which will correctly align the drive dogs 60 with the drive head slots 58. This is because the drive head slots 58 have threefold rotational symmetry whereas the spring bearing guide portion 36 has twofold rotational symmetry. Markings may be provided on the drive tool to remove the possibility of misalignment. Alternatively, if the wrong direction of rotation is chosen, recompressing the spring and rotating the drive sleeve 180° will correct the error. As noted above, in an alternative embodiment the spring bearing guide portion may be arranged to not be rotationally symmetrical to avoid this possible error.

When the drive sleeve 24 is correctly positioned the safety clip 88 can be located in groove 90 and the shaft safety sleeve 8 can be fitted over the drive shaft 2 by sliding over the first stop portion 14 (causing the shaft safety sleeve 8 to deform at longitudinal slots 16, 18. To disassemble the drive tool the safety clip 88 and the shaft safety sleeve 8 must first be removed. Alternatively the shaft safety sleeve may simply slide back until the whole of the retracted drive sleeve 24 is visible. The drive sleeve 24 is retracted against the force of spring 26 until a stop is felt. The stop is caused by spring bearing 30 coming to rest against the edge of groove 40 opposite the spring bearing guide portion 36. Alternatively, or in addition the stop may be caused by the stop face 86 within the drive sleeve coming to rest against the spring thrust face 28. In alternative embodiments the stop may be caused additionally or alternatively by the end of the drive sleeve 24 coming to rest against the drive shaft second stop portion 22. The drive sleeve 24 may then be rotated which drives rotation of the spring bearing 30 through flats 72 bearing against flag 38. This rotation of the spring bearing 30 locks the spring 36 in compression and causes the spring bearing outer flats 108 to align with flats 76 on the drive shaft 2. At that point the drive sleeve may be removed by slight axial movement towards the drive head 2 to release the cupped spring bearing cylindrical portion 104 and than radial movement away from the drive shaft 2 drawing the drive sleeve channel 70 over the spring bearing 30 and drive shaft locking portion 74. To aid cleaning when the drive sleeve 24 is removed the spring bearing 30 may be released from groove 40 to uncompress the spring 26.

The shape of the drive head first portion 46 and corresponding aperture 50 described is generally in the form of a rounded triangle. However, the present invention is not limited to this. Indeed the drive head first portion and aperture may be any shape which allows rotation of the drive head within the cavity to open up space for a drive dog to pass through the aperture to lock the reamer to the drive tool. It is advantages to use a shape having at least two fold symmetry as this reduces the amount by which the drive head must be rotated relative to the reamer to initially align the drive head and in order to lock the drive head to the reamer. In order to ensure that the drive dogs can engage the same aperture as the first portion of the drive head it is necessary to ensure that for the portion of the drive dogs that is intended to pass through the aperture no part of the drive dogs extends outside of the same predetermined shape as the first portion of the drive head, though with the shape rotated about the drive shaft axis relative to its application to the drive head.

It will be appreciated that as a minimum only one drive dog is required in order to drive the reamer. Drive to the reamer may be imparted by the single drive dog and the point of contact between the edge of the reamer in the drive head groove acting in combination. However, by providing at least two drive dogs spaced apart about the drive head it is possible for drive to be imparted to the reamer only through the drive dogs and not also through the drive head groove.

The use of a drive head first portion and aperture having threefold rotational symmetry provides particular advantages. Increasing the amount of rotational symmetry reduces the amount of rotation required in order to engage the reamer. This also assists with the ability of the drive head to self align to the aperture. However, increasing the amount of rotational symmetry reduces the space available for the drive dogs to pass through the aperture. The result is smaller drive dogs which may be more difficult to manufacture with sufficient accuracy to minimise play between the drive tool and the reamer and also which may be harder to clean. A three sided shape provides a balance between these two requirements.

Particular details of the drive shaft 2 and the drive sleeve 24 have been described, including the locking mechanism for engaging and disengaging the drive sleeve on the drive shaft. It will be appreciated that these are only one possible arrangement of features. More generally, a drive tool in accordance with an embodiment of the invention may incorporate a drive sleeve arranged to slide along the drive shaft without rotation for a predetermined distance and then be allowed to rotate such that it can be removed. The particular described arrangement of channel shape and flats upon the drive shaft and spring bearing are only one possible option. While surgical drive tools in accordance with embodiments of the present invention have been described above primarily in connection with driving an acetabular reamer, it will be appreciated that the present invention is not limited to this. Reamers requiring a rotational drive may be required when implanting other prostheses. More generally, the present invention is applicable to any situation in which it is necessary to provide rotational drive to a surgical instrument.

Further modifications to, and advantages of, the present invention will be readily apparent to the appropriately skilled person from the teaching herein, without departing from the scope of the appended claims.

Claims

CLAIMS:
1. A surgical drive tool comprising:
a drive shaft having a first end arranged to couple to a rotational driver;
a drive head coupled to a second end of the drive shaft, a first portion of the drive head not extending outside of a predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis, the first portion of the drive head incorporating a drive head slot; and
a drive dog coupled to the drive shaft and arranged to slide relative to the drive shaft to engage the drive head slot such that the combination of the first portion of the drive head and the drive dog extends outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis;
wherein the drive dog is arranged to retract from the drive head slot to allow the first portion of the drive head to be inserted through an orifice defined by the
predetermined shape in a surgical instrument, the drive head being arranged to rotate within the orifice such that the first portion of the drive head cannot be retracted from the orifice and such that the drive dog can engage the drive head slot through the orifice to limit further rotational movement between the drive tool and the orifice.
2. A surgical drive tool according to claim 1 , wherein the first portion of the drive head comprises at least two spaced apart slots and the surgical drive tool comprises at least two drive dogs arranged to engage the drive head slots, said at least two drive dogs extending towards the drive head from a drive sleeve arranged to slide along the drive shaft.
3. A surgical drive tool according to claim 2, further comprising a resilient element extending between the drive sleeve and a portion of the drive shaft, the resilient element being arranged to bias the drive sleeve towards the drive head such that the drive dogs are biased towards a position in which they engage the drive head slots.
4. A surgical drive tool according to claim 3, wherein the resilient element comprises a spring extending between the drive sleeve and a portion of the drive shaft.
5. A surgical drive tool according to claim 4, wherein the drive sleeve comprises a longitudinal channel arranged to pass over a portion of the drive shaft such that the drive sleeve partially surrounds the drive shaft and wherein the surgical drive tool further comprises a spring bearing mounted on the drive shaft and arranged to slide along the drive shaft, the spring extending between the drive shaft thrust face and the spring bearing, the spring bearing being arranged to engage an internal thrust face within the drive sleeve channel.
6. A surgical drive tool according to claim 5, wherein the spring bearing comprises a non-circular aperture arranged to slide along a corresponding non-circular spring bearing guide portion of the drive shaft such that rotation of the spring bearing about the drive shaft is limited, the spring bearing being further arranged to engage the sides of the drive sleeve channel to limit rotation of the drive sleeve relative to the spring bearing, wherein the drive sleeve, the spring bearing and the spring bearing guide portion of the drive shaft are arranged such that when the drive dogs are engaged in the drive head slots the spring bearing slides along the spring bearing guide portion of the drive shaft causing rotation of the drive sleeve about the drive shaft to be limited.
7. A surgical drive tool according to claim 6, wherein the drive shaft further comprises a groove having a maximum width less than the minimum width of the spring bearing aperture in a plane perpendicular to the drive shaft axis and a length along the drive shaft axis sufficient to accommodate the spring bearing, the groove being positioned along the drive shaft such that when the drive dogs disengage the drive head slots the spring bearing is arranged to engage the groove allowing the spring bearing and the drive sleeve to rotate about the longitudinal axis of the drive shaft.
8. A surgical drive tool according to claim 7, wherein the drive shaft further comprises a locking portion which is non circular in cross section such that in a first radial direction about the drive shaft axis the locking portion has a first width which is narrower than the width of the mouth of the drive sleeve channel, and in a second radial direction the locking portion has a second width which is larger than the width of the mouth of the drive sleeve channel but smaller than the diameter of a body portion of the channel such that the locking portion can rotate within the body portion of the channel.
9. A surgical instrument according to claim 8, wherein when the drive sleeve is mounted on the drive shaft and the spring bearing is positioned on the spring bearing guide portion of the drive shaft the second width of the drive shaft locking portion is aligned with the mouth of the drive shaft channel such that the drive sleeve channel cannot pass over the drive shaft locking portion.
10. A surgical drive tool according to any one of claims 2 to 9, wherein the predetermined shape has at least twofold rotational symmetry.
11. A surgical drive tool according to claim 10, wherein the predetermined shape has three sides and wherein the first portion of the drive head comprises three spaced apart slots arranged to be engaged by three drive dogs with one slot positioned on each side of the predetermined shape.
12. A surgical drive tool according to claim 1 1 , wherein the predetermined shape is defined by three arcs extending between inner and outer circles centred on the drive shaft axis, the arcs being tangential to the inner circle at three spaced apart points and tangential to the outer circle at three spaced apart points intermediate the three spaced apart points on the inner circle.
13. A surgical drive tool according to any one of claims 2 to 12, wherein collectively at least the portion of the drive dogs arranged to engage the slots does not extend outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis.
14. A surgical drive tool according to any one of the preceding claims, wherein the drive head further comprises:
a flange positioned between the drive head first portion and the drive shaft, the flange extending outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis so as to limit insertion of the drive head into an orifice defined by the predetermined shape in a surgical instrument, the drive head slots extending through the flange; and
a groove between the drive head first portion and the flange, the maximum width of the drive head within the groove being less than the minimum width of the drive head first portion perpendicular to the drive shaft axis.
15. A surgical drive tool according to any one of claim 2 to 14, further comprising an outer sleeve arranged to extend around at least part of the drive shaft and to rotate about the drive shaft, the outer sleeve incorporating a first feature arranged to engage the drive sleeve as it slides along the drive shaft to limit the extent of sliding movement of the drive sleeve along the drive shaft such that the drive dogs do not disengage the drive head slots.
16. A surgical instrument set comprising:
a surgical drive tool according to any one of the preceding claim;
a rotational driver arranged to couple to the first end of the surgical drive tool to impart rotational drive to the surgical drive tool; and
a surgical instrument incorporating an orifice defined by the predetermined shape and arranged to be engaged by the drive head such that the surgical drive tool can impart rotational drive to the surgical instrument.
17. A surgical instrument set according to claim 16, wherein the surgical instrument is a reamer comprising a reaming body incorporating cutting edges arranged to remove portions of bone and a coupling portion incorporating the orifice.
18. A method of coupling a rotational driver to a surgical instrument, the method comprising:
coupling a rotational driver to a first end of a drive shaft part of a surgical drive tool such that the rotational driver can impart rotational drive to the surgical drive tool; inserting a first portion of a drive head coupled to a second end of the drive shaft through an orifice in a surgical instrument, the drive head first portion not extending outside of a predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis, and the predetermined shape defining the shape of the orifice; rotating the drive head first portion such that the first portion of the drive head cannot be retracted from the orifice;
sliding a drive dog coupled to the drive shaft towards the drive head such that the drive dog can engage a slot in the first portion of the drive head slot through the orifice to limit further rotational movement between the drive tool and the orifice, the combination of the first portion of the drive head and the drive dog extending outside of the predetermined shape surrounding the drive shaft axis in a plane perpendicular to the drive shaft axis to prevent the drive head being withdrawn through the orifice.
PCT/GB2012/050318 2011-04-08 2012-02-14 A surgical drive tool WO2012136972A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB1105932.6 2011-04-08
GBGB1105932.6A GB201105932D0 (en) 2011-04-08 2011-04-08 A surgical drive tool

Publications (1)

Publication Number Publication Date
WO2012136972A1 true WO2012136972A1 (en) 2012-10-11

Family

ID=44072132

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB2012/050318 WO2012136972A1 (en) 2011-04-08 2012-02-14 A surgical drive tool

Country Status (2)

Country Link
GB (1) GB201105932D0 (en)
WO (1) WO2012136972A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3485821A1 (en) * 2017-10-10 2019-05-22 Symmetry Medical Manufacturing, Inc. Orthopaedic reamer system
EP3530216A1 (en) * 2018-02-23 2019-08-28 Hpf S.R.L. Surgical reamer

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030216716A1 (en) * 2000-06-24 2003-11-20 Yves Desarzens Dual reamer holder for surgical use
WO2004080315A1 (en) * 2003-03-13 2004-09-23 Depuy International Limited An assembly for use in orthopaedic surgery
WO2009024798A1 (en) * 2007-08-23 2009-02-26 Smith & Nephew Plc Medical device and method
WO2010004267A1 (en) * 2008-07-07 2010-01-14 T. J. Smith & Nephew Limited Medical device

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20030216716A1 (en) * 2000-06-24 2003-11-20 Yves Desarzens Dual reamer holder for surgical use
WO2004080315A1 (en) * 2003-03-13 2004-09-23 Depuy International Limited An assembly for use in orthopaedic surgery
WO2009024798A1 (en) * 2007-08-23 2009-02-26 Smith & Nephew Plc Medical device and method
WO2010004267A1 (en) * 2008-07-07 2010-01-14 T. J. Smith & Nephew Limited Medical device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
None

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3485821A1 (en) * 2017-10-10 2019-05-22 Symmetry Medical Manufacturing, Inc. Orthopaedic reamer system
EP3530216A1 (en) * 2018-02-23 2019-08-28 Hpf S.R.L. Surgical reamer

Also Published As

Publication number Publication date
GB201105932D0 (en) 2011-05-18

Similar Documents

Publication Publication Date Title
US4716894A (en) Acetabular cup inserting instrument
US7033363B2 (en) Snap-lock for drill sleeve
EP1537829B1 (en) Medical device comprising instrument insert and means for blocking the movement of the handle
US9364221B2 (en) Surgical stapling device with captive anvil
US9265516B2 (en) Blade retention mechanism for surgical instrument
US5683399A (en) Acetabular cup insertion tool
US7559927B2 (en) Surgical instrument with telescoping attachment
US7276074B2 (en) Angled tissue cutting instrument having variably positionable cutting window, indexing tool for use therewith and method of variably positioning a cutting window of an angled tissue cutting instrument
CA2623409C (en) Prosthetic valve crimping device
CA2116741C (en) Surgical drill
CN102048568B (en) Locking shipping wedge
US20160113649A1 (en) Adapter with fire rod j-hook lockout
US9113917B2 (en) Surgical drill instrument with motor and locking mechanism to receive an attachment and a cutting burr
US5630818A (en) Tool holding mechanism for a motor driven surgical instrument
AU771805B2 (en) Soft tissue repair material fixation apparatus and method
US7846167B2 (en) Driver assembly and fastener apparatus
US6174335B1 (en) Alignment guide for slotted prosthetic stem
US7122028B2 (en) Reconfiguration surgical apparatus
EP1912587B1 (en) Carry and drive device and dental implant
US4600006A (en) Cranial perforator
EP1346787A1 (en) Rotary tool and cutting part comprised in the tool
US4362161A (en) Cranial drill
DE102004051794B4 (en) Coupling system for a medical dissecting tool
JP6276510B2 (en) Joint implant test component
US4456010A (en) Cranial drill

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 12705709

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct app. not ent. europ. phase

Ref document number: 12705709

Country of ref document: EP

Kind code of ref document: A1