Smith & Nephew BIRMINGHAM HIP User manual

Surgical Technique

3
Disclaimer
The following technique is for informational and educational purposes only. It
is not intended to serve as medical advice. It is the responsibility of the
treating physician to determine and utilize the appropriate products and
techniques according to their own clinical judgment for each of their patients.
For more information on any product referenced herein, including indications
for use, contraindications, effects, precautions and warnings, please consult
the product’s Instructions for Use (IFU) prior to use.
Nota Bene
The technique description herein is made available to the healthcare
professional to illustrate the authors’ suggested treatment for the
uncomplicated procedure. In the nal analysis, the preferred treatment is that
which addresses the needs of the specic patient.
BIRMINGHAM HIP™
Resurfacing System
Contents
Indications/Contraindications ........................................................4
Warnings and Precautions .............................................................5
Surgical Approach..........................................................................5
Preoperative Planning ....................................................................6
Intraoperative Templating...............................................................7
Acetabular Preparation ..................................................................8
Curved Cup Introducer.................................................................10
Acetabular Cup Wiring Instruction ...............................................11
X-Bar............................................................................................13
Femoral Preparation .....................................................................14
Using the McMinn Alignment Jig .................................................15
Short Arm Alignment Jig Technique.............................................17
Using the Sleeve Cutter Stop .......................................................21
Using the Stem Drill .....................................................................29
Size Chart ....................................................................................31
Thrombo-embolic Prophylaxis......................................................32
Important Medical Information .....................................................38

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The BIRMINGHAM HIP™ Resurfacing (BHR™) System is a single
use device intended for hybrid fixation: cemented femoral head
component and cementless acetabular component.
The BHR System is intended for use in patients requiring primary
hip resurfacing arthroplasty due to:
• Non-inflammatory arthritis (degenerative joint disease) such
as osteoarthritis, traumatic arthritis, avascular necrosis, or
• Inflammatory arthritis such as rheumatoid arthritis.
The BHR System is intended for patients who, due to their
relatively younger age or increased activity level, may not be
suitable for traditional total hip arthroplasty due to an increased
possibility of requiring future ipsilateral hip joint revision.
Contraindications
• Patients who are female
• Patients with infection or sepsis
• Patients who are skeletally immature
• Patients with any vascular insufficiency, muscular atrophy, or
neuromuscular disease severe enough to compromise implant
stability or postoperative recovery
• Patients with bone stock inadequate to support the
device including:
- Patients with severe osteopenia or patients with a family history
of severe osteoporosis or severe osteopenia.
- Patients with osteonecrosis or avascular necrosis (AVN)
with >50% involvement of the femoral head (regardless
of FICAT Grade).
- Patients with multiple cysts of the femoral head (>1cm).
- Note: In cases of questionable bone stock, a DEXA scan may be
necessary to assess bone stock status.
• Patients with known moderate to severe renal insufficiency
• Patients who are immunosuppressed with diseases such as AIDS
or persons receiving high doses of corticosteroids
• Patients with known or suspected metal sensitivity (e.g., jewelry)
Indications for use

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• Patients who, from plain radiograph pre-operative templating,
appear to require 48mm femoral heads should not be considered
as candidates for BHR implantation. Patients requiring a 48mm
femoral head size are at a moderately elevated risk of requiring
revision surgery earlier than expected. While Smith & Nephew
concluded that the increased risk associated with this head
size does not outweigh the potential benefit to the patient in
the specific circumstance of intra-operative downsizing from
a pre-operatively templated 50mm to a measurement of 48mm
at the time of surgery, surgeons should use their best medical
judgment to consider this information relative to the patient’s
overall medical history and prognosis in determining its
appropriateness as a surgical treatment.
• Patients on medications (such as high-dose or chronic
aminoglycoside treatment) or with co-morbidities (such as
diabetes) that increase the risk of future, significant renal
impairment should be advised of the possibility of increase
in systemic metal ion concentration. Preoperative and
postoperative monitoring of renal function (such creatinine,
GFR, BUN) will be necessary for these patients.
• Only physicians who have received appropriate training and are
familiar with the implant components, instruments, procedure,
clinical applications, adverse events, and risks associated with
the BHR System should use this device. Contact Smith & Nephew
Orthopaedics Ltd. for the surgical technique manual and
procedural training protocol.
• Based on literature reports together with the manufacturer’s
post-market data, the following were identified as risk factors for
early revision:
- Patients who receive a 48mm femoral head;
- Patients who receive a device which is incorrectly positioned;
- Patients who have a diagnosis of avascular necrosis;
- Patients who have congenital dysplasia; and
- Patients who are obese
The more risk factors the patient has, the greater the risk of
procedure failure requiring a revision of the hip.
The surgical approach
The BIRMINGHAM HIP™ Resurfacing device may be implanted
through all normal surgical approaches.
The posterior approach is described in this operative technique.
Warnings and precautions

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Templating
BHR™ template sets (Figure 1) are used to
determine component size and correct implant
positioning. The position of the femoral
component is a most important pre-operative
consideration. Varus positioning must be
avoided and slight valgus is recommended
(Figure 2).
To achieve optimal femoral component
positioning, place the appropriate BHR
template onto the X-Ray. Once happy with the
size chosen the medial head-neck-junction
may be identified to set up the correct
template positioning. This is aided by using
the cut out section on the template which
allows implant position markings to be made
with the template in situ.
With the head-neck-junction identified the
template is rotated around this point until
desired valgus position is achieved with the
implant’s centre line. One limiting factor for
implant positioning is the risk of femoral neck
notching. This may be avoided at the
templating stage by confirming there is no
contact between the superior aspect of the
femur and the template.
Once satisfied with the template positioning,
the X-Ray may be marked on the lateral cortex
of the femur using the appropriate cut-out
section. The marked position shows the
insertion point for the lateral pin used with
the standard Head-Centre-Alignment-Jig.
The distance from the pin insertion point on
the lateral femoral cortex to the tip of the
greater trochanter is measured with the ruler
found on the edge of each template. This
measurement is translated intraoperatively
onto the patient’s femur to achieve optimal
pin placement.
Figure 1
Figure 2
Preoperative planning
medial H/N
junction

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An assessment is made of the femoral neck
diameter using the head/neck template. This
provides vital information as to minimum head
component size that can be safely used and
also the minimum acetabular size that can be
utilised. If significant osteophyte formation is
present on the femoral neck then this should
be removed with rongeurs before definitive
assessment of femoral neck diameter is made
(Figure 3,4).
NOTE: Care should be taken to avoid
damage to the soft tissue and blood
supply during osteophyte removal.
Figure 3
Figure 4
Intraoperative templating

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If the anteroinferior capsule is tight an antero-
inferior radial capsulotomy is made in line with
the psoas tendon. A Hohmann retractor is
placed inferior to the radiographic teardrop. The
acetabular labrum, transverse ligament and
ligamentum teres are excised revealing an
unencumbered view of the complete acetabulum
and a view of the true floor of the acetabulum.
Sequential reaming with hemispherical acetabular
reamers is then performed and in normal
consistency bone, reaming proceeds to 2mm
less than the definitive acetabular component
to be inserted (Figure 5).
In large patients with soft cancellous bone
3mm under-reaming is recommended. In small
patients with sclerotic acetabulae 1mm of
under-reaming is recommended.
The cup trial may be used to determine correct
implant positioning. If in doubt, medical tweezers
can be used to identify optimal seating of the
cup. The trial is 1mm smaller than the definitive
component size (Figure 6).
Posteroinferior and anteroinferior osteophytes
are excised to allow unobstructed cup insertion.
Please note that some designs of acetabular
reamers do not have teeth at the periphery and
the acetabulum may be unreamed at its periphery
making cup insertion difcult (Figure 7).
It is recommended to leave a rim of osteophyte
to prevent Psosas impingement on the wall
of the acetabular component, avoiding
post-operative groin pain.
Figure 5
Figure 6
Figure 7
Acetabular preparation
High Performance Cup Introducer
Inspection Procedure
The following instructions should be followed to
maintain the performance of the BHR™ Cup Introducer:
• All instruments should be inspected before use. Any
instrument found with a loose or absent locking screw
should be returned to Smith & Nephew for
refurbishment. It is particularly important that a thread
locking mechanism is used to secure the screws
otherwise this problem may recur.
• There should be no excessive free play in the cable
tensioning mechanism.

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The desired size of acetabular component is
mounted on the acetabular introducer and
offered up to the acetabular rim. The acetabular
cup is rotated so that its anti-rotation splines
are adjacent to the ischium and pubis. The
acetabular component is then fully impacted
with 15-20˚ of anteversion and 40-45˚ inclination
angle (Figure 8).
The acetabular introducer is removed and the
polyethylene impactor cap is retracted at this
stage to check that the acetabular component is
correctly inserted. Adjustment of the cup position
can be made by re-attaching the acetabular
introducer. Cup removal is facilitated by the use
of the slide hammer extractor attached to the
acetabular introducer.
When it is certain that the component is correctly
inserted, the cup introducer cables are cut and
the cables and the polyethylene impactor cap
removed (Figure 9). If the cup must be removed
after the cables have been cut then separate
cables and extractor assembly are available
(code 900201&2). Any protruding osteophytes at
the acetabular edge are removed with rongeurs.
The femoral head is then reduced into the newly
inserted acetabular component.
Figure 8
Figure 9
* Cautionary statement
DO NOT over tighten the acetabular component on the
introducer. Over tightening and excessive wire tension
may cause wire breakage.
Acetabular Cup Introducer Wire Removal Procedure
The following instructions should be followed to
minimise the risk of separating the plastic coating
when removing the introducer wire.
• Use appropriate wire cutters, in good condition, for
the cutting task.
• Minimise the number of wormholes the wire is pulled
through (multiple cuts).
• Avoid acute angles between the wire and the cup
face during withdrawal.
• If the force required to remove the introducer wire is
excessive, remove the wire by pulling it in the
opposite direction.
• Check that the plastic coating is still present on the
wires following the wires removal.

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These instructions provide important information regarding
assembly and wiring for use of the BHR™ Curved Cup Introducer.
NOTE: This Curved Cup Introducer is for use with BHR
Resurfacing cups only.
Curved Cup Introducer

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The following is the recommended method of
attaching the Curved Cup Introducer to the
acetabular component.
To ensure correct component fixation, please
note that the wire loops are specified as wire
loops 1, 2 and 3.
Wire loop 3
Wire loop 1
Wire loop 2
Fixation nFixation n
Figure 1
Step 1
The acetabular component is placed over
the threaded spigot on the face plate of
the introducer, with the introducer passing
through wire loop 1.
To ensure correct alignment, check that the
fixation fins of the acetabular component are
positioned either side of the device (Figure 1, 2).
Figure 2
Step 2
Wire number 2 is then looped over the wire grip
(Figure 3).
Note: retracting the wire grip a small
way, using the thumb wheel, will apply
some tension to the wires and may aid
the assembly.
Wire loop 2
Figure 3
Acetabular Cup wiring instruction

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Step 3
As in Step 2, now loop wire 3 over the wire grip
(Figure 4). Wire loop 3
Figure 4
Step 4
With the two opposing wire loops (2&3)
positioned through the wire grip now capture
both wires by passing wire loop 1 over the top
(Figure 5).
Figure 5
Step 5
When satisfied that the cup wires are suitably
positioned, secure the device by tightening the
thumb wheel to a satis-factory tension (Figure 6).
Thumb Wheel
Figure 6
Acetabular Cup wiring instruction continued

13
X-Bar
X-Bar (Figure 7)
Figure 7
The X-Bar is attached to the curved Cup
Introducer. (Figure 8)
Figure 8
With the patient positioned correctly align the
impactor so that the appropriate bar on the guide,
left or right, is parallel to the longitudinal axis of
the patient while the vertical bar is perpendicular
to the oor. This will provide approximately 40-45˚
of abduction and 15-20˚ of anteversion. (Figure 9)
Surgical Tip
• Target acetabular component orientation for
optimal bearing function;
40-45˚ of abduction
15-20˚ of anteversion
<45˚ combined stem/cup anteversion
Figure 9

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The desired position of the femoral alignment pin
will be known from the preoperative templating.
Identify the tip of the greater trochanter through
the tissues with a spinal needle.
A ruler is used to measure the desired distance
down from the tip of the greater trochanter
(Figure 1) and the alignment pin is inserted
through the vastus lateralis fibres.
The front and back of the femoral shaft are felt
and pin insertion is then started in a transverse
direction into the mid-lateral cortex (Figure 2). Figure 1
Figure 2
Femoral preparation

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After the outer cortex is breached the drill is
angulated so that the alignment pin is directed
towards the femoral head (Figure 3).
The alignment pin is left protruding 5mm above
the outer fibres of vastus lateralis.
NOTE: It is recommended that “Pin in Femur”
is placed on the nurse’s swab count board.
Figure 3
Using the McMinn Alignment Guide
The appropriate head implant size is set up on
the head centre stylus. The alignment guide
(Figure 4) is hooked onto the alignment pin and
the leg fully internally rotated to deliver the
femoral head into the centre of the wound.
Figure 4

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The adjustable joint in the long arm of the
alignment guide is set so that the guide wire will
be directed down the mid-lateral axis of the
femoral neck (Figure 5a). Bisect the neck with
forceps to aid visualisation (Not illustrated).
Next the proximal portion of the guide is moved
on the femoral head to allow the stylus to be
passed around the femoral neck, having first
been set to the desired femoral component size
(Figure 5b, 5c).
When the stylus can be passed around the
femoral neck at an equal distance, then the
central cannulated rod is locked into position by
impacting the teeth on this rod into the femoral
head. Thus the whole assembly is stabilised.
Fine-tuning of this position can then occur.
Figure 5a
Figure 5b Figure 5c
Femoral preparation continued

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Templating
BHR™ template sets are used to determine
component size and correct implant positioning.
The position of the femoral component is a most
important preoperative consideration. Varus
positioning must be avoided and slight valgus
is recommended.
To achieve optimal femoral component
positioning, place the appropriate BHR template
onto the x-ray. Once satisfied with the size
chosen the medial head/neck junction may
be identified to set up the correct template
positioning. This is aided by using the cut out
section on the template which allows implant
position markings to be made with the template
in situ.
With the head/neck junction identified the
template is rotated around this point until desired
valgus position is achieved with the implant’s
centre line. One limiting factor for implant
positioning is the risk of femoral neck notching.
This may be avoided at the templating stage
by confirming there is no contact between the
superior aspect of the femoral neck and the
template.
When the desired template position has been
achieved, the distance from the tip of the lesser
trochanter to the centre line of the implant
template is measured. The long axis of the ruler
template (Figure 6) is overlayed with the centre
line of the implant template to identify the pin
insertion point on the intertrochanteric crest.
This measurement is translated intraoperatively
onto the patient’s femur using the measuring
guide (Figure 7) to achieve optimal pin, Jig and
ultimately femoral implant positioning. The pin
insertion point may be marked using
electrocautery or a medical needle to ensure
optimal pin, jig and femoral positioning.
NOTE: To achieve correct measurement from
the tip of the lower trochanter to the pin
insertion point, the patient’s leg must not
be externally rotated while taking the x-ray
in supine position of the pelvis.
X-ray magnication must be taken into
account during this preparation.
10
20
30
40
50mm
9012-4120™Trademark of Smith & Nephew REV 0 06/06
Short Arm Alignment Jig Ruler
0120
Figure 6- Short Arm Alignment Jig Ruler
IMAGE NOT TO SCALE
Figure 7 - Measuring Guide
Short Arm Alignment Jig technique

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Short Arm Alignment Jig technique continued
The measuring guide is placed on the tip of the
lesser trochanter translating the preoperative
measurement on to the intertrochanteric crest.
The alignment pin insertion point can now be
marked (Figure 8).
Using the marked insertion point on the
intertrochanteric crest, the assembled jig is
fixed to the femur by inserting the collared
alignment pin through the hole in the distal slot
of the alignment arm (Figure 9).
NOTE: Care should be taken to use the
correct collared alignment pin as this differs
from the item used with the traditional long
arm jig.
The alignment jig can now be used to correctly
position the long guide wire and ultimately
achieve correct implant positioning (Figure 10).
The operation of the short arm jig remains
consistent with the traditional McMinn alignment
jig as described earlier in this surgical technique.
On correct positioning of the long guide wire the
alignment guide assembly is released from the
femur by first removing the collared pin.
Figure 8
Figure 9
Figure 10

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A guide wire is inserted when the desired
position of the alignment guide has been
achieved (Figure 11).
The central rod is removed and the guide
assembly completely removed.
NOTE: Guide wires are intended for single
use only
The stylus is re-inserted on the guide wire and
a final check made to ensure that the stylus
passes comfortably around the femoral neck
(Figure 12).
NOTE: A re-drill guide is available for the
correction of minor alignment errors (Not
Illustrated).
Secondly, a check is made to ensure that when
the sleeve cut is made some peripheral femoral
head support exists. This is not only important
with respect to support for the implant, but is
very important with respect to the pressurisation
of cement. Care must be taken in cases of
slipped epiphysis, or in pistol-grip deformity
where the femoral head is not symmetrically
located on the femoral neck.
Figure 11
Figure 12

20
Short Arm Alignment Jig technique continued
When the desired position of the guide wire has
been achieved then the guide wire is overdrilled
to the appropriate depth for the implant being
inserted (Figure 13).
At this stage a hole is drilled and the vent
is inserted into the lesser trochanter and
connected to the second suction device
(not illustrated).
The guide wire is removed and the guide rod
inserted (Figure 14).
The most stability is achieved when the transition
between the bearing and the solid distal tip is
aligned with the apex of the femoral head
(Figure 15).
Figure 13
Figure 14 Figure 15