surgical technique - mediservis · surgical technique the profemur®z is a femoral implant designed...

Surgical Technique

• Proven design philosophy

• Simple surgical technique

• Modular Necks for optimal joint reconstruction

Disclaimer

Proper surgical procedures and techniques are the responsibility of the medical professional. These guidelines are furnished for information purposes only. Each surgeon must evaluate the appropriateness of the procedures based on his or her personal medical training and experience. Prior to use of the system, the surgeon should refer to the product package insert for complete warnings, precautions, indications, contra-indications and adverse effects. Packaging inserts are also available by contacting Wright Medical Technology Inc.

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Surgical Technique

The PRoFEMuR®Z is a femoral implant designed with a rectangular cross section and a conical profile characterised by a constant increase in volume from the distal tip to the proximal area. This double taper configuration is intended to provide wide cortical contact, rotational stability and primary fixation thereby allowing secondary osteo-integration of the implant. Distally, the stem features a tapered tip in order to reduce potential for cortical impingement and associated anterior thigh pain.

The large metaphyseal section of the stem is designed to aid rotational stability and helps to prevent stem subsidence. It encourages a rapid osseointegration process in the proximal region and reduces stress on the calcar. The modular neck housing incorporates a polished collar that increases in height in proportion to stem size.

The wide range of modular necks, originally designed in 1985, boast a long clinical follow-up of over 140.000 cases. Rigorous laboratory tests have proven a near absence of “fretting” due to micro-movements, total reliability and stability under load. The neck of a prosthetic implant represents the extra-medullary component to which stability and functionality of the coxo-femoral joint are entrusted. The orientation of the neck has a determining influence on the distribution of the mechanical forces and stresses transferred to the implant. Modular necks permit the adjustment of the implant to the femoral morphology thus allowing optimal positioning of the implant according to individual patient morphology. use of the different neck angles allow restoration of leg length, varus-valgus orientation, ante-version, retro-version, off-set and correct joint mobility which is essential in hip arthroplasty. by means of screws.

The STEM

The MODULAR NECK

Wright Medical Modular Neck System,

comprising of: Neck length Neck style S L XL Straight x x x V.V. 8° x x x V.V. 15° x x A.R. 8° x x x A.R. 15° x x A.R./V.V.1 x x A.R./V.V.2 x x

(4 styles x 2 lengths + 3 styles

x 3 length)

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SIZES

The PRoFEMuR®Z is available in nine proportionally increasing sizes ensuring the system will suit a large patient population.

THE MATERIALThe PRoFEMuR®Z is manufactured from titanium alloy (Ti6Al4V) with a corundum sandblasted surface with a specific roughness of (Ra ≈ 8µ), known to be surface suitable for bone on-growth.

THE INSTRUMENTATIONThe precise and user friendly instrumentation allows for accurate implant positioning according to pre-planning. Rasps can be driven manually or by a pneumatic instrument. The rasps also serve as trial prosthesis as they can be utilized with a trial neck.

BIBLIOgRApHy

“FRETTING WEAR IN A MoDuLAR NECK HIP PRoSTHESIS”M. Viceconti ET. AL. JBMR: Vol. 35, 207 - 216 (1997)

“DESIGN RELATED FRETTING WEARING MoDuLAR NECK PRoSTHESIS”M. Viceconti ET. AL. JBMR: Vol. 30, 186 - 191 (1996)

“CoLLo AMoVIBILE: CRITERI DI PRoGETTAZIoNE, ANALISI DELLo STATo TENSIoNALE E PRoVE MECCANICHE” Technical dossier: on file at Wright Medical

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Accurate pre-planning is useful to act as a guide for what size of prosthesis and which kind of modular neck and head are most likely to be used. Templates are available with a 15% magnification and show all the various centres of rotation that can be obtained with the modular neck system.

Implanting the PRoFEMuR®Z does not require a specific technique and can be performed using a routine surgical approach. Experience indicates that the modular neck system is very helpful in a MIS technique as it allows for a reduction in length of incision.

Approximately 10.20mm below the greater trochanter, resect the neck at a 45° angle to the longitudinal axis of the femur.

Following the osteotomy of the neck and removal of the femoral head, the intra-medullary canal is opened with the box chisel. In order to avoid a possible varus position of the femoral component, it is advocated to make sure that the location of this point of entry provides an access for the rasps in line with the femoral axis. The monobloc starter rasp can be used for a first preparation of the bony envelop, followed by the modular rasps until the final size is determined.The rasp handle shows a scale to assist in determining the seating of the rasp (and thereby of the implant) in relation to the tip of the greater trochanter. The outcome can be compared with the preferred implant size/position found at pre-planning.Preparation of the femoral canal is completed when the rasp is considered to be stable.

Note | on the rasp there is a clear junction between teeth and collar.This junction is also found on the final implants and acts as a landmark for seating of the implant.

Note | In case the rasp handle can not be used, the Extraction Ring (PPG30170) can be mounted into the rasp pocket to extract the rasp.

Surgical Technique

Pre-Operative Planning

Preparation of the Femur

Size A E OFF-SET

1 126 0 30.5

2 131 0 30.5

3 136 1.5 31.5

4 141 3 32.5

4 146 4.5 33.5

6 151 6 34.6

7 156 7.5 35.7

8 161 9 36.8

9 166 10.5 38

off-set is based on a short straight modular neck + medium modular head

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The final implant corresponds to the rasp used to test stability, trial reduction and consequent choice of modular neck and modular head.The stem is inserted with the special stem final impactor APA01114, and the final impactor PPF60200 can be used for final seating of the component. once seated a further trial reduction can be performed to confirm the chosen modular neck and head.

The choice of the final modular neck depends on the stability and range of motion experienced at trial reduction. Except for the straight necks all other styles of modular neck have a dual function thereby doubling the number of head centre options.Carefully clean and dry implant taper and modular neck pocket prior to assembly. Affix the neck by striking the head impactor with a light mallet tap, and then apply the femoral head. If a trial reduction is preferred prior to applying the final head implant, a trial head can be used.

Note | If using a ceramic head push and turn the head 180 degrees to securely lock it in place.

Surgical Technique

Choosing the Final implant

Choice of the Modular Neck

Final Reduction

BRIEF SUMMARY OF NECK OPTIONS

Straight necks create a neutral neck axis of 135°. Long and X-Long necks can

often avert the need for a skirted head.

Varus necks 8°/15° decrease the femoral neck angle to 127°/120° (neutral

position is 135°); the femoral head shifts medially and inferiorly; leg length is

shortened; offset is increased.

Valgus necks increase the femoral neck angle to 143°/150° (neutral position is

135°); the femoral head shifts laterally and superiorly; leg length is increased;

offset is decreased.

Anteverted necks shift the femoral head anteriorly relative to the stem

by 8° or 15°.

Retroverted necks shift the femoral head posteriorly relative to the stem

by 8° or 15°.

A.R. / V.V. necks combine anteversion/retroversion and varus/valgus necks to

offer a broad range of multi-dimensional head positions. Each A.R. / V.V. neck

provides 4° of A.R. and 6° of V.V.

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FEMORAL HEAD REMOVAL

The femoral head is removed by placing a plastic tipped femoral head impactor

or tamp on the under side of the femoral head and applying mallet blows

upward until the femoral head is removed.

FEMORAL NECK EXTRACTION

Screw the femoral neck adaptor onto the femoral neck in a clockwise motion.

The neck extractor goes over the top of the femoral neck and the adapter is

captured by the adjustable hook. By squeezing the handle an extraction force

is applied to the neck as the neck extractor pushes against the shoulder of the

prosthesis. The extractor is designed such that it will accommodate any style

and size of neck in combination with any style and size of prosthesis.

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Description Code Size Stem Length

Stem PHA00232 1 126 mm









TYPE A Code

STRAIGHT

Short 28 PHA01202

Long 38.5 PHA01204

X-Long 46 PHA01206

VARUS / VALGUS 8°

Short 27 PHA01252

Long 38 PHA01254

X-Long 46 PHA01256

VARUS / VALGUS 15°

Short 27 PHA01262

Long 38 PHA01264

ANTE / RETRO 8°

Short 28 PHA01232

Long 38.5 PHA01234

X-Long 46 PHA01236

ANTE / RETRO 15°

Short 28 PHA01242

Long 38.5 PHA01244

ANTE / RETRO – VARUS / VALGUS 1

Short 28 PHA01222

Long 38.5 PHA01224

ANTE / RETRO – VARUS / VALGUS 2

Short 28 PHA01212

Long 38.5 PHA01214

Surgical Technique - Sizes and References

Implants

Dimensional Chart Femoral Necks (mm)

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Surgical Technique - Instrumentation

Description Code Size Quantity

Box Chisel PPR67704 1 1

Rasps APA01070 Starter

APA01072 1 1

APA01074 2 1

APA01076 3 1

APA01078 4 1

APA01080 5 1

APA01082 6 1

APA01084 7 1

APA01086 8 1

APA01088 9 1

Handle for

Pneumatic Impactor PPA30091 1

Broach Handle PPW38078 1

Extraction Ring PPG30170 1

Hexagonal Screwdriver PP275400 1

DIMENSIONAL CHART | STEMS

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Description Code Quantity

Stem Impactor APA01114 1

Final Impactor for stem PPF60200 1

Neck Extractor APA09500 1

12/14 Adaptor for

Neck Extractor APA09501 1

Wrench for Neck Extractor APA09502 1

Head Impactor PPR67702 1


Instrument

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Description Code Quantity

TRIAL NECK ( STRAIGHT – SHORT ) APA08102 1

TRIAL NECK ( STRAIGHT – LONG ) APA08104 1

TRIAL NECK ( STRAIGHT – X-LONG ) APA08106 1

TRIAL NECK ( ANT.-RET. / VAR.-VAL.1 SHORT) APA08112 1

TRIAL NECK ( ANT.-RET. / VAR.-VAL.1 LONG ) APA08114 1

TRIAL NECK ( ANT.-RET. / VAR.-VAL.2 SHORT) APA08122 1

TRIAL NECK ( ANT.-RET. / VAR.-VAL.2 LONG ) APA08124 1

TRIAL NECK ( ANT.-RET. 8° SHORT ) APA08132 1

TRIAL NECK ( ANT.-RET. 8° LONG ) APA08134 1

TRIAL NECK ( ANT.-RET. 8° X-LONG ) APA08136 1

TRIAL NECK ( ANT.-RET. 15° SHORT ) APA08142 1

TRIAL NECK ( ANT.-RET. 15° LONG ) APA08144 1

TRIAL NECK ( VAR.-VAL. 8° SHORT ) APA08152 1

TRIAL NECK ( VAR.-VAL. 8° LONG ) APA08154 1

TRIAL NECK ( VAR.-VAL. 8° X-LONG ) APA08156 1

TRIAL NECK ( VAR.-VAL. 15° SHORT ) APA08162 1

TRIAL NECK ( VAR.-VAL. 15° LONG ) APA08164 1

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Description Code Size Quantity

Trial Head 12/14 APA02112 Ø 22 mm M. 1

APA02113 Ø 22 mm L. 1

APA02121 Ø 28 mm S. 1

APA02122 Ø 28 mm M. 1

APA02123 Ø 28 mm L. 1

APA02131 Ø 32 mm S. 1

APA02132 Ø 32 mm M. 1

APA02133 Ø 32 mm L. 1

APA02142 Ø 36 mm S. 1

APA02144 Ø 36 mm M. 1

APA02146 Ø 36 mm L. 1

X-ray template

15% magnification MSS3CL01E


Instrument

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The PRoFEMuR®Z Revision stem is developed with the proven geometry of the primary stem in mind. The revision stems show a proportional growth in all dimensions and range in length from 176 mm to 216 mm. The proximal part of the ‘Z’ Revision is equal to the corresponding primary stem, however throughout the range it’s length has been increased by 40 mm.

The well-known conical features of the primary system have been kept unchanged. Therefore primary stability, rotational stability and load distribution over the major length of the stem is anticipated, although presence of bone depending. The PRoFEMuR® Z Revision stem can also be used in those primary cases where additional stem length is required.

In revision cases the integrity of the proximal femoral bone is often compromised, potentially leading to a fissure. The corners at the proximal-medial part of the Z Revision have been rounded off for stress reduction

A full series of dedicated broaches is available. These broaches work in combination with all instruments used with the PRoFEMuR® Z primary

Revision Stems

Instrumentation

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The PRoFEMuR®Z system comes with a single set of instruments accommodating both the primary as well as revision components. Pre-operative planning plays an important role in the succesful outcome of joint reconstruction. A series of templates is available to estimate the size of prosthesis to be used as well as the preferred off-set, CCD-angle and leg length (MSS3CL02EB).. It is advocated to achieve a fit into good femoral bone, distal to the tip of the previous prosthesis, thereby bridging possible bone defects.

After removal of the failed implant (and possible cement layer), the femoral canal is openend by means of a straight rigid reamer. Care should be taken to be in full alignment of the femoral shaft axis to prevent a possible varus position. It therefore might be necessary to enlarge the femoral canal into the greater trochanter.

Broaches are used to prepare the bony envelop, usually starting with the broach 2 sizes smaller than the prosthesis size found at templating. Gradually increase broach size until proper stability and depth is achieved.After removal of the broach handle, the broach can be used as a trial prosthesis by applying a trial modular neck and head. Suggestion: start with a short straight neck and 0 head.

The modular neck system allows for multiple options to fine-tune the joint reconstruction for the best possible functional outcome and thereby patient satisfaction.

once the preferred femoral neck and modular head have been determined, the trial neck is removed and the broach/trial prosthesis is extracted, to be rapleced by the appropriate final implants. First the stem is implanted, followed by proper cleaning of the modular neck pocket. If required, another trial reduction can be performed by using the trial femoral neck and head components.After cleaning the pocket the final neck / head components are applied to the stem and both are secured by a light hammer tap.

The hip is reduced and the wound if closed in a routine fashion

Size A B C D E Implant nr. Rasp nr.

3 176 37.5 20.6 10.1 1.5 PHA00606 APA01048

4 181 39.0 21.8 10.5 3.0 PHA00608 APA01050

5 186 40.5 23.0 10.9 4.5 PHA00610 APA01052

6 191 42.0 24.1 11.4 6.0 PHA00612 APA01054

7 196 43.5 25.3 11.8 7.5 PHA00614 APA01056

8 201 45.0 26.5 12.2 9.0 PHA00616 APA01058

9 206 46.5 27.6 12.6 10.5 PHA00618 APA01060

10 211 48.0 29.0 13.1 12.0 PHA00620 APA01062

11 216 49.5 30.5 13.5 13.5 PHA00622 APA01064

Surgical Technique

Surgical Technique

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Notes

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Acetabular Cup

Hemi-spherical Flattened dome 12 Equatorial finsPlasma sprayedTitanium coating

w/wo HA coating

Hemi-spherical Flattened dome 14° Rim FlarePorous coating titanium beadsw/wo HA coating

Group Head ø

Cup Size

A28

42

B 44

C32

46 - 48

D 50

E

36

52 - 54

F 56 - 58

G 60 - 62 - 6466-68

Group Head ø

Cup Size

B28

44

C 46 - 48

D32

50

E 52 - 54

F

36

56 - 58

G 60 - 62 - 6466 - 68

Biolox Delta CeramicSuper Finished Metal

A-CLASS™ AdvancedX-Linked Polyethylene

Cups come with 3 holes for additional fixation by means of screws. The in-line screw holes are positioned away from the dome of the cup to achieve maximum lever arm, optimal purchase in the iliac wing and thereby maximise stability. The screws have 20° freedom of direction.From size 44 and up these screw holes are closed with a plug, including the dome hole.

The increase in head diameter provides an increase in unrestricted range of motion and a larger ‘jump-distance’, which reduces the potential for impingement and associated sub-luxation or dislocation. The unique combination of internal taper and RIM-LoCK™ locking groove allows the use of Metal, Ceramic or Polyethylene bearing liners in a single shell design.

Large bearing diameter uncemented acetabular components

X-ray: courtesy of Dr. E. Tozzi,Pisa-Calambrone, Italy

EH007-807E

www.wmt.com™ Trademarks and ®Registered marks of Wright Medical Technology, Inc.

© 2005 Wright Medical Technology, Inc. All Rights Reserved.

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surgical technique - mediservis · surgical technique the profemur®z is a femoral implant designed...

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