GB2567161A

GB2567161A - An attachment mechanism for a surgical instrument

Info

Publication number: GB2567161A
Application number: GB1716128.2A
Authority: GB
Inventors: Murgatroyd Matthew
Original assignee: DePuy Ireland ULC
Current assignee: DePuy Ireland ULC
Priority date: 2017-10-03
Filing date: 2017-10-03
Publication date: 2019-04-10
Also published as: GB201716128D0

Abstract

An attachment mechanism for detachably coupling a first component 10 with a second component as part of a surgical instrument. The attachment mechanism is provided on first component 10 and comprises: a first member 12 having a longitudinal axis X1 extending between the first member’s distal and proximal ends 14&16; and a second member 50 in a sliding relationship with the first member 12. First member 12 comprises a deflectable connection element 26 comprising an urging surface 28 to releasably engage with a complementary connection element on the second component. Second member 50 slides relative to the first member 12 to urge against urging surface 28 of connection element 26, so deflecting it from a first position where connection element 26 is disengaged from the second component’s complementary connection element, to a second position where the connection element 26 is deflected relative to first member’s longitudinal axis X1 to engage with the second component’s complementary connection element. The attachment-mechanism may comprise a locking mechanism to lock the first and second members 12,50 in a position relative to each other where the connection element 26 is in the second position. First component 10 may be a handle and the second component may be a cutting tool, a broach, a reamer or a grater.

Description

AN ATTACHMENT..MECHA^§M^

The present invention relates to an attachment mechanism for surgical instrument components. In particular, the invention relates to an attachment mechanism that can be used ίο releasably attach one component to another component as part of a surgical instrument. The invention also relates to a surgical instrument comprising the attachment mechanism.

Surgical instruments often have modular components or parts that can be coupled and decoupled by means of a simple attachment mechanism. Such an attachment mechanism may be in the form of actuating levers or latches. Examples of modular components that are required to be releasably detached from each other includes reamer heads onto reamer drivers., broaches onto broach handles, drill bits onto drill drivers and impaction heads onto impaction handles.

A problem associated with current attachment mechanisms, such as those based on levers or latches, is mechanical fatigue resulting from cyclic loading. Weld fractures are particularly problematic as these might lead to parts ofthe attachment mechanism, such as pins, becoming loose. This might result in the surgical instrument becoming unusable, 20 or parts inadvertently dropping into the surgical site.

Another drawback with current attachment mechanisms is that they require a twohanded approach in order to engage and disengage the two components.

Summary.ofihe.inyenliqn

According to an aspect of the invention there is provided an attachment mechanism for detachably coupling a first component io a second component as part of a surgical instrument, the attachment mechanism being provided on the first component and 30 comprising;

a first member having a distal end, a proximal end and a longitudinal axis extending between the distal and proximal ends, the first member comprising a deflectable connection element configured to releasably engage with a complementary connection

-2element on the second component, the deflectable connection element comprising an urging surface;

a second member in a sliding relationship with the first member:

in which the second member is configured to slide relative to the first member to urge against the urging surface of the deflectable connection element to deflect the deflectable connection element from a first position in which the deflectable connection element is disengaged from the complementary connection element io a second position in which the deflectable connection element is deflected relative to the longitudinal axis of the first member to engage with the complementary connection element.

The design of the attachment mechanisms described herein provides an improved robustness to surgical instruments (e.g., a broach handle) over the conventional designs. This improvement is achieved, for example, by the uncoupling/isolation of any pins required for securing components together within a surgical instrument (e.g., a broach) from the attachment mechanism. This minimises the likelihood of failure due to fatigue (e.g., weld failure).

Optionally, the first member is a sleeve and the second member is an arm located within the sleeve. The arm may be configured to slide along the longitudinal axis of the sleeve such that a part of the arm to urges against the urging surface of the deflectable connection element.

Optionally, the sleeve includes a pair of opposed deflectable connection elements.

Optionally, the arm extends along the longitudinal axis of the sleeve.

In some constructions of the attachment mechanism, a distally located end of the second component is configured to slide into contact with the urging surface of the or each of the deflectable connection members to deflect the or each deflectable connection element from the first position to the second position.

Optionally, the distally located end of the second member is urged against the urging surface of the or each deflectable arm when the first member slides over the second

-3member. Optionally, the first member slides in a proximal direction relative to the second member.

The attachment mechanism may include a biasing element, for example a spring, to bias the second member in a position in which the second member is not in contact with the urging surface of the or each deflectable connection member on the first member.

In another construction of the attachment mechanism, a distally located portion of the second member is tapered to provide a ramp surface extending outwardly, in a distal direction, from a longitudinal axis of the second member., and in which the ramp surface urges against the urging surface of the or each deflectable member as the second member slides relative to the longitudinal axis of the first member to deflect the or each deflectable connection element from the first position to the second position.

Optionally, the distally located end of the second member is urged against the urging surface of the or each deflectable connection element when the second member slides within the first member. Optionally, the second member slides in a proximal direction relative to the sleeve.

The second construction of the attachment mechanism may also include a biasing element, for example a spring, to bias the arm in a first position in which the ramp surface is not in contact with the inwardly facing arm contacting portion, of each of the pair of deflectable members.

In order for the attachment mechanism to provide a surgical instrument that can be operated with one, rather than two hands, the engagement of the first component (e.g., a handle) with the second component (e.g., a cutting tool) docs not require the operation of a button or lever. For example, in the case of the engagement of a broach handle (i.e., the first component) with a broach (i.e., the second component), the broach may be retained in a vertical position, such that the opening of the proximally-located recess into which the handle will connect, faces uppermost. As the distal end of the broach handle is inserted into the recess, by a downward pushing action, the two components become connected together by virtue of the activation of the attachment mechanism.

For safety considerations, it is advantageous that the two components remain locked together until a user selects to disconnect them. It is also advantageous to be able to extract the second component from the surgical site as an assembly with the first component, rather than having to utilise a separate extraction tool.

Accordingly, the attachment mechanism as described herein optionally further comprises a locking mechanism to lock the first and second members in a position relative to each other at which the or each deflectable connection element is in the second position (i.e, the engaged position).

The user interface of the locking mechanism may in the form of a button or lever. Only when the user unlocks the locking mechanism is it possible for the two components to be disassembled. This prevents the unintentional disassembly of the two components during their operation. This is of particular advantage in situations in which the second component is a cutting tool, and more particular a rotary cutting tool. A rotary cutting tool which inadvertently disconnects from its handle has serious safety impheations.

According to a further aspect of the invention there is provided a device comprising the attachment mechanism as described herein. The device may be a surgical 20 instrument. In some constructions, the first component of the surgical instrument may comprise a handle. In some constructions, the second component may comprise a cutting tool, for example a broach, reamer or grater.

According to a further aspect of the invention there is provided a method of engaging a first component of a surgical instrument assembly with a second component surgical instrument assembly, the method comprising the steps of;

(i) using an attachment mechanism provided on a. first component as herein described;

(ii) contacting a distal end of the first component with a second component to which the first component is to be engaged;

(iii) causing the first and second members to slide relative to each other so as to urge a part of the second member against the urging surface of the or each deflectable

-5· connection, element to thereby deflect the or each deflectable connection element from a first position in which the or each deflectable connection element is disengaged from the complementary connection element on the second component to a second position in which the or each deflectable connection element is deflected relative to the longitudinal axis of the first member and into engagement with the complementary connection element on the second component.

each other comprises applying a force, for example a sliding force to the hand first component or an impaction force to the proximal end to its proxima

Optionally, the step of causing the first and second members to slide relative to e grip of the end.

Optionally, the step of causing the first and second members to slide relative to each other comprises causing the first member slide over the second member.

Optionally, the step of causing the first and second members to slide relative to each other comprises causing the second member slide over the first member.

According to a still further aspect of the invention, there is provided a method of disengaging a first component of a surgical instrument assembly from a second component of a surgical instrument assembly, the method comprising the steps of using an at tachment mechanism provided on a first component as described herein, the method comprising the step of:

causing the first and second members to slide relative to each other so as to remove an urging force applied to the urging surface of the or each deflectable connection element by a part of the second member, to thereby deflect the or each deflectable connection element from a second position in which the or each deflectable conne engaged with the complementary connection element on the second component to a first position in which the or each deflectable connection element is deflected relative to the longitudinal axis of the first component and out of engagement with the complementary connection element on the second comnonent.

A setion element ί

Optionally, the method of disengaging a first component from a second component as described above also comprises unlocking the arm from a position along the longitudinal axis of the sleeve at which the arm urges each deflectable connection element into the second position. The step of unlocking the arm may include a user depressing a button.

l^efdescriptton.ofthemyentton

Constructions of a surgical instrument comprising the attachment mechanism will be described hereinafter, by way of example only, with reference to the accompanying drawings in which like reference signs relate to like elements and in which:

FIG. 1 shows an isometric view of a surgical instrument which comprises a first construction of the attachment mechanism in the disengaged position;

FIG. 2 show's the assembled surgical instrument of FIG. 1;

FIG. 3 shows a cross-sectional view of a surgical instrument which comprises a first construction of the attachment mechanism in the disengaged position (FIG. 3a) and 20 engaged position (FIG. 3b);

FIG. 4 show s a cross-sectional view of a broach handle and a broach prior to connection (FIG. 4a) and connected (FIG. 4b);

handle to a broach;

FIG. 6 shows a cross-sectional view of a surgical instrument which comprises a second construction of the attachment mechanism in the disengaged position (FIG. 6a) and 30 in the engaged position (FIG. 6b).

-7FIG. 7 shows a cross-sectional view of a surgical instrument which comprises a third construction of the attachment mechanism in the disengaged position (FIG. 7a) and in the engaged position (FIG. 7b).

FIG. 8 shows a cross-sectional view of a surgical instrument which comprises a fourth construction of the attachment, mechanism in the disengaged position (FIG. 8a) and in the engaged position ( FIG. 8b).

Detui led deseri pt io n

Constructions of the attachment mechanism are described in the following with reference to the accompanying drawings.

FIGS 1 to 5 are illustrative of a surgical cutting instrument that includes a first construction of the attachment mechanism as herein described. For illustrative purposes, the first component 10 is a broach handle and the second component 30 is a broach.

The broach handle 10 includes a first member in the form of a generally rectangular hollow sleeve 12. The sleeve includes a distal end 14, a proximal end 16 and a longitudinal axis Xi extending between the distal and proximal ends. The sleeve also includes a top wall 18, a bottom wall 20, a first lateral side wall 22 and a second lateral side wall 24. A transverse pin hole 25 is provided within die first and second lateral side walls 22, 24.

The sleeve 12 includes a pair of deflectable connection elements 26 which are configured to releasably engage with a complementary connection element on the second component. Each of the pair of deflectable connection elements 26 may be in the form of a hook-like element, configured to releasably hook into a complementary connection element on the second component. This complementary connection element may be in the form of a recess or groove within the second component. This recess or groove may be on an interior surface of the second component.

The hook-like element may be generally L-shaped. The long arm of the '‘L” may extend distally from at or near to the distal end of the sleeve. The short arm of the ’‘L’“ may extend outwardly and away from the longitudinal axis of the sleeve. The short arm is configured to releasably hook into a complementary connection element (e.g., a recess or groove) within the second component.

Each deflectable connection element. 26 includes an inwardly facing urging surface

28.

31.

Each deflectable connection element 26 also includes an outwardly facing projection

This projection is generally rectangular, and is configured to snap-fit into an appropriately dimensioned rectangular slot 32 within the top wall 18 and the bottom wall 20 of the sleeve, respectively. This form of connection provides a cantilevered connection member.

Each ofthe pair of deflectable connection elements 26 is deflectable from a neutral, first ('‘non-engaged’) position in which each deflectable connection element is not engaged with the complementary connection element to a second (“engaged”) position in which each deflectable connection element is deflected away from the longitudinal axis of the sleeve 12 to engage with the complementary connection element.

Grooves 34a, 34b extend longitudinally along the inner surface ofthe top wall 18 and bottom wall 20 ofthe sleeve from the proximal end 16 towards the distal end 14. These grooves are configured for sliding receipt of a second member, in the form of arm 50 (described below;).

The grooves 34a, 34b extend towards a depressible button 36. The button is a hollow cuboid. The button includes two lateral side walls 38, a top wall 40 and a bottom wall 42. The inner surface of the bottom wall includes a detent 44. This detent 44 is in the form of a step which extends between the two lateral side walls 38.

The button 36 is biased into a first position by a spring 48 located below the bottom wall 42. In this biased position, the top wall 40 of the button 36 protrudes above the top wall 18 ofthe sleeve 12.

The broach handle also includes a second member, shown here in the form of an arm

50. The ami includes a distal end 52, a proximal end 54 and a longitudinal axis Xi extending between the distal and proximal ends. This longitudinal axis is colinear with the longitudinal axis of the sleeve. An impaction plate 55 may be integral with, or assembled to the proximal end of the arm.

The ami 50 also includes a top wall 56, a bottom wall 58, a first, lateral side wall 60 and a second lateral side wall 62.

The top wall 56 and the bottom wall 58 of the arm includes ridges 64a, 64b. The ridges are dimensioned for sliding receipt by the grooves 34a, 34b on the sleeve.

An indentation 66 is located within the bottom wall 58 of the arm. This indentation is dimensioned for receipt of the step 44 that extends between the two lateral side walls 38 of the sleeve.

The arm also includes a generally rectangular transverse slot 68 that extends linearly along the longitudinal axis of the arm. The slot has smoothed edges. The arm further includes a transverse pin hole 70.

The arm 50 is assembled within the sleeve 12 such that ridges 64a, 64b are received within the grooves 34a, 34b on the inner surface of the sleeve.

A pin 72 is inserted through the transverse pin hole 25 on the first lateral side wall 22 of the sleeve, through the transverse slot 68 on the arm, and then through the transverse pin hole 25 on the second lateral side wall 24 of the sleeve. The pin 72 is then welded in place. This connection secures the ami 50 within the sleeve 12, whilst enabling the arm to slide relative to the sleeve along the longitudinal axis of the sleeve. The pin 72 functions as a stop member, and limits the distal and proximal movement of the sleeve over the arm as a result of its abutment against the distal and proximal edges of the transverse slot 68.

-10As a result of contact between the distal end of the sleeve and the second component (e.g., the broach) the sleeve 12 slides in a proximal direction over the arm 50, moving from its original (unrestrained) position to a second (constrained) position. During this sliding action, the distal end 54 of the arm is caused to be urged against the inwardly facing urging surface 28 of each deflectable connection element 26. This results in the deflection of each deflectable connection element from the neutral, first (‘non-engaged”) position to the second (“ engaged”) post uon.

The sliding of the sleeve in. a distal direction over the arm 50 during reversion of the sleeve from its second (constrained) position ίο its original (unrestrained) position, causes the distal end 54 of the arm to be moved out of contact from the inwardly facing urging surface 28 of each deflectable connection element 2o. This releases the urging force applied by the arm. This results in the deflection of each deflectable connection element from the second (“engaged”) position to the neutral, first (“non-engaged”) position.

is original (unrestrained) nosition.

X .·* A

Spring 53a, 53b are located at the distal end of the arm and interact with the sleeve. These springs bias the sleeve to

In the construction illustrated, the engagement of each deflectable connection element 26 with a complementary connection element on the second component (e.g., the broach) can be performed in a one-handed operation by the user.

The illustrated construction includes a locking feature in the form of button 36. The provision of this button prevents any inadvertent sliding of the sleeve relative to the arm unti l the user depresses the button. As such, the distal end of the arm is prevented from moving out of contact with the inwardly facing urging surface 28 of each deflectable connection element 26 until the user has pressed the button. This prevents the automatic disengagement of the first component (i.e., the broach handle) from the second component (i.e., the broach).

-11When a user depresses the button 36, the spring 48 is compressed. The detent 44 (in the form of step) is moved clear of indentation 66. This enables the sleeve to be moved distally.

The broach handle also includes a handle member 80. The handle member is hollow.

The handle member has a proximal end 82 and a distal end 84. The broach handle also includes a top wall 88. a bottom wall 90, a first lateral side wall 92 and a second lateral side wall 94. Preferably, the handle member has a length that is sufficiently long such that when the handle member is assembled over the arm 50 and the sleeve 12, the distal end of the handle member 80 extends at least past the location of the pin 72.

Grooves (not shown) extend longitudinally along the inner surface of the top wall 88 and bottom wall 90 of the handle member from about midway along the length of the handle member towards the proximal end 82. These grooves 96a, 96b are configured for sliding receipt of the ridges 64a, 64b on the arm 50.

A transverse pin hole 96 is provided within the first, and second lateral side walls 92,

94.

The handle member 80 is assembled to the arm 50 and the sleeve 12 by sliding the handle member 80 over the arm 50 in a distal direction. Ridges 64a, 64b are received within the grooves 96a, 96b on the inner surface of the handle member.

When assembled the transverse pin hole 96 on the handle member is aligned with the transverse pin hole 70 on the arm. A pin 100 is inserted through the transverse pin holes 70, 96 and welded in place, thereby securing the handle member 80 to the arm 50.

The pin 100 has the potential for a weld failure. Any risk that this pin may fail and become dislodged from the instrument may be mitigated by overmolding of the pin.

The interaction of the ridges 64a, 64b on the arm 50 with the grooves 34a, 34b on the inner surface of the sleeve 12 and the grooves 96a, 96b on the inner surface of the handle

-12member 80 provides an improvement in the mechanical integrity of the device. This results from the fact that when the instrument is impacted via the strike plate 55, the impaction load is transferred down through the arm and, via the ridges, into the arm member 50 and sleeve 12, respectively. Consequently, the pin 72 is isolated from the impaction load.

As a direct load is not transmitted through the pin 72, the risk of a weld failure at this site is minimised. However, even if a weld failure does occur, the fact that pin 72 is housed within the handle member 80 means that the pin is contained within the assembly and cannot become dislodged from the transverse pin hole 25. This is advantageous for the safety of the surgical instrument during its lifetime of use. It is also advantageous, because even if a weld failure occurs, the attachment mechanism can still function, as the pin 72 remains in

FIG. 6 is illustrative of a surgical cutting instrument that includes a second construction of the attachment mechanism as herein described. For illustrative purposes, the first component 110 is a broach handle intended io attach to a second component 130, i.e., a broach (not shown).

The broach handle 110 includes a first member, shown here as a generally rectangular hollow sleeve 112, The sleeve includes a distal end I14, a proximal end 116 and a longitudinal axis X?. extending between the distal and proximal ends. The sleeve also includes a top wall I 18, a bottom wall 120, a first lateral side wall (not shown) and a second lateral side wall (not shown), A transverse pin hole (not shown) is provided within the first and second lateral side walls (not shown).

The sleeve 112 includes a pair of deflectable connection elements 126 ’which are configured to releasably engage with a complementary connection element on the second component. Each of the pair of deflectable connection elements 126 may be in the form of a hook-like element, configured to releasably hook into a complementary connection element on the second component. This complementary connection element may be in the form of a recess or groove within the second component. This recess or groove may be on an interior surface of the second component.

-13The hook-like element may be generally I.,-shaped. The long arm of the L may extend distally from at or near to the distal end of the sleeve. The short arm of the L may extend outwardly and away from the longitudinal axis of the sleeve. The short arm is 5 configured to releasably hook into a complementary connection element (e.g., a recess or groove) within the second component.

Each deflectable connection element 126 includes an inwardly facing urging surface

Each deflectable connection clement 126 also includes an outwardly facing projection 130. This projection is generally rectangular, and is configured to snap-fit into an appropriately dimensioned rectangular slot 132 within the top wall 118 and the bottom wall 120 of the sleeve, respectively. This form of connection provides a cantilevered connection member.

Each of the pair of deflectable connection elements 126 is deflectable from a neutral, first (“non-engaged”) position in which each deflectable connection element is disengaged from the complementary connection element to a second (“engaged”) position in which each deflectable connection element is deflected laterally away from the longitudinal axis Xi of the sleeve 112 to engage with the complementary connection element on the broach.

The broach handle also includes a second member, here shown in the form of an arm 150. The arm includes a distal end 152, a proximal end 154 and a longitudinal axis X2 extending between the distal and proximal ends. This longitudinal axis is colinear with the longitudinal axis of the sleeve. The arm 150 also includes a top wall 156, a bottom wall 158, a first lateral side wall (not shown) and a second lateral side wall (not shown). An impaction plate (not shown) may be integral with, or assembled to, the proximal end 116 of the sleeve 112.

A distally located portion of the distal end 152 of the arm 150 is tapered to provide a ramped surface 154 extending outwardly, in a distal direction, from the lc the arm.

ngitudinal axis of

The arm also includes a generally rectangular transverse slot 168 that extends linearly along the longitudinal axis of the arm. The slot has smoothed edges. T he arm further includes a transverse pin hole (not shown).

When the arm 150 is assembled within the sleeve I 12, a pin 172 is inserted through the transverse pin hole on the first lateral side wall of the sleeve, through the transverse slot 168 on the arm 150, and then through the transverse pin hole on the second lateral side wall of the sleeve. The pin 172 is then welded in place. This connection secures the arm 150 within the sleeve 112, whilst enabling the arm to slide relative to the sleeve along the longitudinal axis of the sleeve. The pin 172 functions as a stop member, and limits the distal and proximal movement of the arm within the sleeve as a result of its abutment against the distal and proximal edges of the transverse slot 168.

A biasing spring 152 is located at the proximal end 154 of the arm 150.

When the distal end 152 of the arm 150 contacts a surface (e.g., a broach), the arm is pushed in a proximal direction. This pushing action compresses the biasing spring 152. This pushing action also causes the ramp surface 154 to move proximally towards the inwardly facing urging surface 128 of each deflectable connection element 126. As contact is made between the ramp surface and the inwardly facing urging surface 128 of each deflectable connection element 126 an urging force is applied against the inwardly facing urging surface 128. This causes the deflection of each deflectable connection element laterally from the neutral, first (“non-engaged’) position to the second (“engaged”) position.

In this second construction of the attachment mechanism, the outer surface of the arm remains in contact with each deflectable connection element throughout linear sliding of the arm in both the proximal or distal direction. However, when the arm is returned to its original position (by the action of the biasing spring 152, as described below), the ramp surface 154 is moved out of contact with the inwardly facing urging surface 128 of each deflectable connection element 126. This removes the previously applied urging force. This causes the deflection of each deflectable connection element from the second (“engaged”) position to the neutral, first (non-engaged) position.

The illustrated construction includes a locking feature in the form of the depressible button 136. The provision of this button prevents any inadvertent sliding of the arm relative to the sleeve until the user depresses the button. As such, the distally-located ramp surface 154 at the end of the arm is prevented from moving out of contact with the inwardly facing urging surface 128 of each deflectable connection element 126 until the user has depressed the button, 't his prevents automatic disengagement of the first component (i.e., the broach handle) from the second component (i.e., the broach).

The button 136 is biased into a first position by a live spring latch 148 that extends in a proximal direction along the outer surface of the top wail 156 of the arm 150. The latch is generally [..-shaped. The short end of the “L” is configured for receipt in a notch 174 provided within the inner surface of the top wall 118 of the sleeve 112. In the biased position, the top wall 140 of the button 136 protrudes above the top wall 118 of the sleeve 112.

When the arm is pushed in a proximal direction as a result of the distal end 152 of the arm 150 contacting a surface (e.g., a broach), as discussed above, the short arm of the “L” of the live spring latch 148 moves proximally into engagement with the notch 174. This locks the arm in this position.

Only when a user depresses the button 136 can the arm revert to its original position under the biasing action of the biasing spring 152. Depressing the button causes the bottom wall 176 of the button to be pushed against the long arm of the “L”. This causes the short arm of the “L” to become disengaged from the notch 174, freeing the arm from its mechanics 1 constraint.

The unrestrained arm is then free to spring back to its original position under the action of the biasing spring 152.

16A handle portion, similar to the handle portion 80 described in reference to the first construction of the attachment mechanism may be assembled to the sleeve 112 and arm 150.

FIG. 7 is illustrative of a surgical cutting instrument that includes a third construction of the attachment mechanism as herein described. For illustrative purposes, the first component 210 is a broach handle and the second component 330 is a broach.

The broach handle 210 includes a first member, shown here in the form of a generally cylindrical sleeve 212. The sleeve includes a distal end 214, a proximal end 216 and a longitudinal axis X3 extending between the distal and proximal ends.

An impaction plate 218 may be integral with, or assembled to, the proximal end 216 of the sleeve.

The sleeve 212 also includes a distally located deflectable connection element 226 which is configured to releasably engage with a complementary connection element on the broach. The deflectable connection element 226 may be in the form of a hook-like element, configured to releasably hook into a complementary connection element on the broach, hi the illustrated construction, file complementary connection element on the broach is a notch

332.

At the proximal end of the connection member 226 there is an outwardly facing projection 228 configured to snap-fit into an appropriately dimensioned slot 230 within the wall member of the sleeve. This form of connection provides a cantilevered deflectable connection member.

At the distal end of the connection member 226 there is an outwardly facing projection 232 which is configured to releasably hook into the complementaiy connection element on the broach. At the distal end of the connection member 226 there is also an mwardlv facing urging surface 23

-17The deflectable connection element 226 is deflectable from a neutral, first (“nonengaged”) position in which the deflectable connection element is not engaged with the complementary connection element to a second (‘'•engaged”) position in which the deflectable connection element is deflected laterally away from the longitudinal axis X?, of the sleeve 212 to engage with the complementary connection element in the broach.

The sleeve includes an elongate channel 236 that extends from the distal end 214 of the sleeve in a longitudinal direction along axis X?>. Channel 236 is dimensioned for sliding receipt of a second member, here shown as an arm 238. A slot 240 extends through the shaft sleeve 212.

The arm has a proximal end 242 and a distal end 244.

The proximal end 242 of the arm includes two opposed, spaced apart fingers. The fingers are spaced apart by a gap of a sufficient dimension to enable the inner surface of each finger to slide over the outer surface of the sleeve. The proximal end of the arm has a pin hole 243.

A portion 248 of the distal end 244 of the arm is configured for receipt within a recess 334 in the proximal surface of the broach 330.

A pin 246 is received within pin hole 243 and spans the gap between the two opposed, spaced apart fingers.

Accordingly, as will be described in further detail below, the arm can be displacement linearly along the longitudinal axis X:> of the sleeve, from a first position in which the pin 246 abuts the proximal end of the blind bore 240, to a second position in which the pin is located towards the distal end of the blind bore.

When the arm is in the first position, the outer surface of the arm is not in contact with the inwardly facing urging surface 234 of the deflectable connection element 226. As the arm slides distally within the sleeve, the outer surface of the arm gradually moves into

-18contact with the inwardly facing urging surface 234 of the deflectable connection element 226. This contact urges the deflectable connection element 226 laterally in relation to the longitudinal axis Xj of the sleeve.

The broach handle 210 also includes a grip member 250. The grip member is attached to and surrounds the proximal portion of the sleeve 212.

When the user wishes to connect the broach handle to the broach, the user can grip the grip member 250 with one hand and push the grip member distally over the sleeve. This action allows the grip member to be linearly displaced from a first ‘non-engaged” position io a second '‘engaged’’ position to which it is biased by a spring (not shown) captured in a spring pocket 251 between the sleeve 212 and grip member 250,

Due to the mechanical linkage of arm 2,38 and the grip member 250, as the grip member is linearly displaced in a distal direction, the arm is slidably displaced into urging contact with the inwardly facing urging surface 234 of the deflectable connection member 226. This results in lateral displacement of the outwardly lacing projection 232 in relation to the longitudinal axis Xs of the sleeve and hence engagement of the deflectable connection element 226 with the complementary connection element on the broach. The broach handle and broach are thus reversibly connected.

In an alternative method of use. the user may strike the impaction plate 218 with a suitable tool.

The broach handle and broach remain connected until the user wishes for them to be disconnected. To disconnect, the user depresses button 252 - which functions to lock the sleeve in the second “engaged” position.

Upon depression of the button, the sleeve will revert to its original position. The arm 30 is caused to be linearly displaced in the proximal direction. The urging force applied by the arm to the inwardly facing urging surface 234 of the deflectable connection element 226 is removed. As the urging contact is gradually removed, the deflectable connection element is

-19medially displaced in relation to the longitudinal axis X3 of the sleeve. Consequently, the outwardly facing projection 232 of the deflectable connection element 226 is dislodged from the complementary connection element within the broach handle. The broach handle and broach are thus disconnected.

The illustrated configuration of the attachment mechanism is advantageous because the design results in the isolation of the impaction/extraction forces from the handle locking mechanism. Instead the forces are transmitted via the sleeve. The isolation of the locking mechanism from these forces improves the durability of the mechanism.

FIG. 8 is illustrative of a surgical cutting instrument that includes a fourth construction of the attachment mechanism as herein described. For illustrative purposes, the first component 310 is a broach handle and the second component 430 is a broach.

Notably, this construction differs from the first, second and third constructions by the engagement of the broach handle with the broach being achieved by the medial rather than lateral displacement of the deflectable connection element relative to the longitudinal axis of the sleeve

c.

The broach handle 310 further includes a first member 312. The first member has a proximal end 314 and a distal end 316. A longitudinal axis X4 extends between the distal and proximal ends.

The distal end 316 is configured for receipt within a recess 432 within the proximal surface of the broach 430.

The distal end 316 of the first member 312 also includes a distally located deflectable connection element 318 which is configured to releasably engage with a complementary connection element on the broach. In the illustrated construction, the complementary connection element on the broach is a notch 434.

-20The deflectable connection element 318 includes an outwardly facing urging surface

320

The deflectable connection element is cantilevered. As illustrated, the deflectable connection element 318 may be in the form of a hook-like element, configured to releasably hook into a complementary connection element on the broach.

The deflectable connection element 318 is deflectable from a neutral, first (‘“nonengaged”) position in which the deflectable connection clement is not engaged with the complementary connection element on the broach to a second (“engaged”) position in which the connection member is deflected towards the longitudinal axis X4 of the first member to engage with the complementary connection element on the broach.

The broach handle 310 includes a second member 322. The second member 322 includes a distal end 324 and a proximal end 326 that extends from a grip member 328. In some constructions, the second member 322 and the grip member 328 may be welded together. The distal end of the second member 322 overlaps a part of the deflectable connection member 318.

When the user wishes to connect the broach handle to the broach, the user can grip the grip member 32,8 with one hand and push the grip member in a distal direction. This pushing action has to overcome a force provided by a biasing spring which biases the grip member to its original position. The biasing spring (not shown) is captured in a spring pocket 329 located between the first member 312 and the grip member 328.

The distal movement ofthe grip member causes the second member 322 to be distally displaced from, the first “non-engaged” position to a second “engaged” position. During this distal displacement, the inner surface 330 of the second member is caused to be slidably displaced against the outwardly facing urging surface 230 of the deflectable connection member, and apply an urging force. This results in the deflectable connection element being deflected medially relative to the longitudinal axis X4 ofthe first member. This leads to the engagement ofthe distal end of the deflectable connection element with the complementary

-21conneetion element on the broach. The broach handle and broach are thus reversibly connected.

The broach handle and broach remain connected until the user wishes for them to be disconnected. To disconnect, the user depresses button 330 - which functions to prevent the grip member from returning to its original position, to which it is biased. When the user depresses the button, the grip member reverts to its original position. By doing the second member is caused to be linearly displaced in the proximal direction. The urging contact between the inner surface 330 of the second member 322 and the outwardly facing urging surface 320 of the deflectable connection element is removed. As the urging force is gradually removed, the deflectable connection element is laterally displaced in relation to the longitudinal axis X.4 of the first member. Consequently, the distal end of the deflectable connection element is dislodged from the complementary connection element within the broach handle. The broach handle and broach are thus disconnected.

Although particular constructions of the invention have been described, it will be appreciated that many modifications/additions and/or substitutions may be made within the scope of the claimed invention.

Claims

I. An attachment mechanism for detachably coupling a first component to a second component as part of a surgical instrument, the attachment mechanism being provided on the first component and comprising;

a first member having a distal end, a proximal end and a longitudinal axis extending between the distal and proximal ends, the first member comprising a deflectable connection element configured to releasably engage with a complementary connection element on the second component, the deflectable connection element comprising an urging surface;

a second member in a sliding relationship 'with the first member;

in which the second member is configured to slide relative to the first member to urge against the urging surface of the deflectable connection element to deflect the deflectable connection element from a first position in which the deflectable connection element is disengaged from the complementary connection element to a second position in which the deflectable connection element is deflected relative to the longitudinal axis of the first member to engage with the complementary connection element.
2.

The attachment mechanism of claim 1, in which the first member is a sleeve and the second member is an arm located within the sleeve and being configured to slide along a longitudinal axis of the sleeve to urge against the urging surface of the deflectable connection element.
3.

The attachment mechanism of claim 2, in which the sleeve includes a pair of opposed deflectable connection elements.
4. The attachment mechanism of claim 2 or 3, in which the arm extends along the longitudinal axis.

The attachment mechanism of any of claims 2 to 4., in 'which a distally located end of the arm is configured to slide into contact with an inwardly facing urging surface of the
5.

-23or each of the deflectable connection elements to deflect the or each deflectable connection element from the first position to the second position.
6.

The attachment mechanism of claim 5, in which the distally located end of the arm is urged against the inwardly facing urging surface of the or each deflectable connection element when the sleeve slides over the arm.

biasing

The attachment mechanism of any preceding claim, further comprising a element to bias the first member in a first position in which the second member is not m contact with the urging surface of the or each deflectable connection element.

The attachment mechanism of claim 7, in which the biasing element is a spring.

9.

The attachment mechanism of claim 2, in which a distally located portion of the tapered to provide a ramp surface extending outwardly, in a distal direction, from the longitudinal axis of the arm, and in which the ramp surface urges against an inwardly facing urging surface of the or each of the deflectable connection elements as the sleeve slides along the longitudinal axis of the arm to deflect the or each deflectable connection element from the first position to the second position.

arm
10. The attachment mechanism of claim 9, in which the distally located end of the arm. is urged against the inwardly facing urging surface of the or each deflectable connection element when the arm slides within the sleeve.
11. The attachment mechanism of claim 9 or 10, further comprising a biasing element to bias the arm in a first position in which the ramp surface is not in contact with the inwardly facing urging surface the or each deflectable connection element.

The attachment mechanism of claim 11, in which die biasing element is a spring.

The attachment mechanism of claim 1, in which the attachment mechanism further comprises a locking mechanism to lock the first and second member in a position relative to each other at which the or each deflectable connection element is in the second position.

13.
14. A device comprising the attachment mechanism according to any preceding claim.
15. The device of claim 14, in which the device is a surgical instrument
16. The device of claim 15, in which the first component comprises a handle and the second component comprises a cutting tool.
17. The device of claim 16, in which the second component is a broach, reamer or 10 grater.
18. A method of engaging a first component of a surgical instrument assembly with a second component of a. surgical instrument assembly, the method comprising the steps of;

(i) using an attachment mechanism provided on a first component according to any of claims 1 to 13;

(ii) contacting a distal end of the first component with a second component to which the first component is to be engaged;

(iii) causing the first and second members to slide relative to each other so as to urge a part of the second member against the urging surface of the or each deflectable connection element, to thereby deflect the or each deflectable connection element from a first position in which the or each deflectable connection element is disengaged from the complementary connection element on the second component to a second position in which the or each deflectable connection element is deflected relative to the longitudinal axis of the first member and into engagement with the complementary connection element on the second component.
19. The method of claim 18. in which the step of causing the first and second members to slide relative to each other comprises applying a force to the proximal end of the first component.
20. A method of disengaging a first component of a surgical instrument assembly from a second component of a surgical instrument assembly, the method comprising the steps of using an attachment mechanism provided on a first component according to any of claims 1 to 13, the method comprising the step of:

causing the first, and second members to slide relative to each other so as to remove an urging force applied to the urging surface of the or each deflectable connection element by a part of the second member, to thereby deflect the or each deflectable connection element from a second position in which the or each deflectable connection element is engaged with the complementary connection element on the second component to a first position in which the or each deflectable connection element is deflected relative to the longitudinal axis of the first component and out of engagement with the complementary connection element on the second component.
21. The method of claim 20, in which the method further comprises a step of unlocking the second member from a position relative to the first member at which a part of the second member urges against the urging surface of the or each deflectable connection elemen
22, The method of claim 21, in which the step of unlocking the arm comprises a user depressing a button.