Helica hip

HELICA Hip Prosthesis

Surgery Manual

veterinary implants

Surgery Manual Preoperative Planning Pre-planning of the operation is essential for optimal implant seating. The cup and stem sizes required, as well as the anticipated head length, are established using X-ray templates.

To this end, templates in a ratio of 1.15:1 and 1:1 are available to the operator.

The choice of the best stem size is limited by the lenght and the diameter.

The HD X-Ray image gives the information about the lenght of the stem. The Frog positioned X-ray image gives the limit of the stem diameter in the section of the smallest neckdiameter.

max. length max. diameter

The choice of the best screw cup size can be measured by one of the images and is limited by the medial acetabular cortex.

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HELICA Hip Prosthesis Modular System Size Range Femoral Stems

ø08 mm x 26 mm ø09 mm x 28 mm ø10 mm x 28 mm ø11 mm x 32 mm ø12 mm x 32 mm

ø Length

Acetabular Cups

ø26 mm ø28 mm ø30 mm ø32 mm ø18 mm, Short ø18 mm, Middle ø18 mm, Long ø18 mm, XLong ø18 mm, XXLong

Femoral Heads (+0 mm) (+3 mm) (+6 mm) (+9 mm) (+12 mm)

ø

Length

ø

Operative Approach to the Hip Joint The standard longitudinal lateral approach with exposure of the anterior aspect of the joint should be used for this hip operation.nted.

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Surgery Manual Resection of the Femoral Head In the Helica Hip System, the resection line is located upside of the bone-cartilage interface direct through the femoral head. The resection cut is made perpendicular to the femoral neck.

Preparation of the Bed for the Screw Cup Reaming of the acetabulum is performed in stages using acetabular reamers, starting with the smallest and progressing to the largest.

Once the planned socket size has been achieved, punctuate bleeding should ideally be seen from all around the subchondral region.

The size of the last acetabular reamer used determines the size of the screw socket to be implanted.

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HELICA Hip Prosthesis

Final Reamer

Depth Reamer

Sample of the Preparation of the acetabular Bed

Dysplastic Acetabulum

Step 1

Step 2

Step 3

Step 1: Drilling a through boring up to the medial acetabular cortex and measuring the thickness.

Step2: Start reaming with the 24 mm “depth reamer�. Go sure by measurement that you are into the required depth. This procedure normally takes 3 or 4 times of measuring.

Step 3: Using the final reamer for surfacing the required diameter. For example the 26 mm reamer is the final and surfacing reamer for the 26 mm screw cup. The same applies for the other sizes.

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Surgery Manual Implantation of the Screw Cup

The first step is to attach the insertion plate corresponding to the size of socket to be used to the square-section T-grip. The screw socket is attached to the insertion plate and introduced into the prepared acetabulum. Depending upon operator requirements, a navigation aid can be attached to the T-grip.

The next step is to align the screw socket in the acetabulum. The angle of inclination is determined with the navigation aid. With the patient in the lateral position, the alignment should result in the alignment shaft being parallel to the surface of the operating table.

The operator establishes the anteversion angle by reference to the local anatomic conditions.

Once correct alignment has been achieved, the screw socket is screwed into the Acetabulum using the T-grip and light presure (turning clockwise).

The screw on the socket taps itself into the acetabulum. The screwing step is finished once the pole of the socket has reached the base of the acetabulum. Over-tightening should be avoided.

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HELICA Hip Prosthesis Preparation of the Marrow Cavity for the Femoral Shaft The marrow cavity is initially opened using a small drill (2,0 or 2,5 mm). This drill is positioned centrally on the resection surface and should go trough the lateral cortex. The long axis of the drill must follow the midline axis of the femoral neck, so that a CCD angle of 145° to 147° is achieved. The waisted course of the femoral neck must be followed while doing this.

The next step is to open the boring step by step starting with the smallest drill and ends with the drill that is provided for the implant size.

Tip: All drills should be coupled by a machine adaptor to a power drill with a three-jaw chuck suitable for 6 mm bits.

If required (taking into account the operative planning), the marrow canal can be widened using sequentially bigger drills. A variety of drill diameters are available to the operator for this step. The last drill used determines the size of the implant to be used (see Table 1).

Drill Size ø4,5 mm ø5,5 mm ø6,5 mm ø7,5 mm ø8,5 mm

Implantat Size ø08 mm x 26 mm ø09 mm x 28 mm ø10 mm x 28 mm ø11 mm x 32 mm ø12 mm x 32 mm

Table 1: Implant size in relation to drill diameter to use

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Surgery Manual Face-milling of the Femoral Neck Following drilling out of the marrow cavity, the femoral neck is milled flat. This step provides optimal seating of the segmented flange of the Stem onto the stump of the femoral neck.

The face-milling tool consists of a milling plate and a guide pin. The diameter to which the marrow cavity has been drilled out determines the diameter of the guide pin to be used. The selected guide pin is screwed into the milling plate. The construct is then connected to the drill via the machine adaptor.

During the milling process, the guide pin must run in the marrow cavity without bending. The milling process is complete when the milling plate lies snugly on the resection surface of the femoral neck circumferentially.

The length of the guide pin is harmonised with the length of the corresponding HELICA Stem.

So it is ensured not to deep can be milled.

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HELICA Hip Prosthesis Implantation of the HELICA Stem There is a seating instrument available for implantation of the HELICA femoral stem. This is attached to the three-edged wedge on the conical end of the prosthesis. Next, the implant is placed on the prepared femoral neck and oriented so that the long axis of the implant follows the course of the drilling in the femoral neck. Then the femoral shaft is screwed in with light pressure (turning clockwise).

Tip: In order to support the self-tapping action of the thread on the HELICA prosthesis during insertion, it may be necessary to back out the screw by about a quarter turn for each full turn of insertion.

The insertion process is complete when the segmented collar of the implant sits snugly on the stump of the femoral neck. A gentle press-fit should be obtained.

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Surgery Manual Trial Relocation In order to permit optimal restoration of joint function, trial femoral heads and trial cup inlays are available in each size. The length of the heads changes in 3 mm steps. By trial relocation while using a variety of trial femoral heads, the tendency to sublux and the range of motion can be assessed.

Tip: In contrast to the implantable femoral heads, the trial heads do not result in conical jamming onto the femoral shaft and also do not generate a snap-on effect during relocation.

Insertion of the Cup Inlay Insertion of the Cup Inlay is achieved with the aid of the seating instrument. The inlay is attached to the adaptor and inserted into the screw Cup. A light tap on the strike plate of the seating instrument snaps the inlay into the screw Cup. It is important to ensure that the rim of the inlay sits flush with the socket margin.

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HELICA Hip Prosthesis Selection and Implantation of the Femoral Head After trial relocation and selection of the appropriate size, the corresponding femoral head is placed on the conical end of the femoral shaft. A light tap using the seating instrument achieves fixation. Finally, the joint is relocated.

During this step, the femoral head must snap into the inlay.

Tip: It is important to ensure that the cushion of air between the femoral head and the inlay is expelled. This can be achieved by repeated pressing of the head into the inlay, as well as by abduction/ adduction movements.

Aftercare of the Patient Careful education of the owner regarding the degree of exertion of the dog following the operation is very important for success.

There should be complete rest for the first 6 weeks following the operation. The daily walks should be short and stairs should be completely avoided.

Correct positioning of the implant is confirmed by check X-ray under sedation 6 weeks after the operation. Thereafter, the loading can be increased and after a further 2 weeks, no more restriction of movement is necessary.

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Surgery Manual HELICA Instrument Set Set 1: HELICA Hip Stem

15

10

16

14

9 8

13 7

12

6

2

11 1

3

12

4

5

Position

Description

REF-Nr.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Femoral Head Seating Instrument Femoral Shaft Seating Instrument Trial Femoral Head ø18 mm, Short Trial Femoral Head ø18 mm, Middle Trial Femoral Head ø18 mm, Long Marrow Cavity Drill ø4,5 mm Marrow Cavity Drill ø5,5 mm Marrow Cavity Drill ø6,5 mm Marrow Cavity Drill ø7,5 mm Marrow Cavity Drill ø8,5 mm Centering Pin ø4,5 mm for Plane Milling Tool Centering Pin ø5,5 mm for Plane Milling Tool Centering Pin ø6,5 mm for Plane Milling Tool Centering Pin ø7,5 mm for Plane Milling Tool Centering Pin ø8,5 mm for Plane Milling Tool Plane Milling Tool

300-SK-0 300-SH-0 300-PH-S 300-PH-M 300-PH-L 300-VB-45 300-VB-55 300-VB-65 300-VB-75 300-VB-85 300-ZS-45 300-ZS-55 300-ZS-65 300-ZS-75 300-ZS-85 300-PF-0

HELICA Hip Prosthesis

Set 2: Acetabular Cup

20

19

22 27

17

18

32

31

29

30

28

26 21 25 24 23

Position

Description

REF-Nr.

17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

Screw Cup Insertion Plate ø26 mm Screw Cup Insertion Plate ø28 mm Screw Cup Insertion Plate ø30 mm Screw Cup Insertion Plate ø32 mm T- Handle for Screw Cup Insertion Plate Seating Instrument Cup Inlay Acetabular Reamer ø24 mm Acetabular Reamer ø26 mm Acetabular Reamer ø28 mm Acetabular Reamer ø30 mm Acetabular Reamer ø32 mm Navigational Aid for Screw Cup Insertion Tool Trial Cup Inlay ø26 mm Trial Cup Inlay ø28 mm Trial Cup Inlay ø30 mm Trial Cup Inlay ø32 mm

300-ES-26 300-ES-28 300-ES-30 300-ES-32 300-TE-0 300-SI-0 300-AR-24 300-AR-26 300-AR-28 300-AR-30 300-AR-32 300-NP-0 300-PI-26 300-PI-28 300-PI-30 300-PI-32

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veterinary implants INNOPLANT veterinary Hรถfestraร e 25 30163 Hannover Germany Phone: ++49-511-64079-55 Fax: ++49-511-64079-56 Mail: info@innoplant-vet.de www.innoplant-vet.de

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