METS

Hemi-PelvisConed

Surgical procedure

Surgical Procedure

Contents

1.0

2.03.04.0

5.0

Product overview 21.1 Indications1.2 Absolute contra-indications1.3 Relative contra-indications1.4 Capabilities and restrictions of use

Components of the coned hemi-pelvis and ancillary 3

Instrumentation overview 4

Operation instructions and guidelines 5 – 64.1 Pre-operative planning4.2 Recommendations for component selection4.3 Prosthetic insertion

Parts and order references 7

1

1.0 Product overviewThe coned hemi-pelvis is designed to provide an off-the-shelf range of specialised hemi-pelvic reconstructive shells for acetabular cup support to be used for intensive hemi-pelvic bone reconstruction. Pelvic anchoring is provided by a fixed stem augmented with bone cement and reinforced with pins and screws, producing a stable acetabular reconstruction. Having created the acetabulum, a suitable acetabular cup is cemented into the cone for use with a total hip replacement. This device has been designed to complement and work with the METS range.

1.1 Indications– Major acetabular bone loss– Revision hip procedures– Bone tumour

1.2 Absolute contra-indications– Infection and sepsis

1.3 Relative contra-indications– Inadequate or incomplete soft

tissue coverage– Uncooperative or unwilling patient or

patient unable to follow instructions– Foreign body sensitivity. Where materials

sensitivity occurs, seek advice with respect to testing

– Vascular disorders, neuromuscular disorders or muscular dystrophy

– Obesity

1.4 Capabilities and restrictions of use– The components should only be used

in the manner specified. Any deviation from this may reduce the in-service life of the prosthesis.

– The coned hemi-pelvis is designed to work in conjunction with a suitably sized cemented cup, up to 50mm (outer diameter). This could be plastic, ceramic or cobalt chrome. Cups with fins, spikes, studs, HA coated, or anything else which prohibits the fit or fixing using cement is not permitted and could lead to mal-alignment, excessive wear and premature failure.

– The acetabulum is reconstructed using a suitably sized coned hemi-pelvis (anchoring is provided by a fixed stem), augmented with bone cement and reinforced with pins and screws. A suitable acetabular cup is cemented into the cone for use with a total hip replacement.

– The implant components are for SINGLE USE only and they must not be re-used.

– A set of instruments is provided to assist insertion of the prosthesis. The reamers that are provided are also used as the trial components.

– This implant is produced from titanium alloy and therefore, under no circumstances, must it be allowed to come into contact with any stainless steel devices (such as bone screws, wires or plates) as this would induce galvanic corrosion.

Modular Coned Hemi-Pelvis1.0 Product Overview

2 – 3

Modular Coned Hemi-Pelvis2.0 Components of the coned hemi-pelvis and ancillary

2.0 Components of the coned hemi-pelvis and ancillary

Multi-axisymmetric holes for optimal bone screw alignment and cement fixing

Large internal diameter shell for cup sizes up to 50mm outer diameter.

ShellOD=63mmID=56mm

Part HA coated for better bone integration

Cutting teeth to ensure positive insertion with maximum rotational stability

Steinmann pins

Bones screws

Modular Coned Hemi-Pelvis3.0 Instrumentation overview

3.0 Instrumentation overview

1 Long impactor 2 Reamer 9 > 7mm3 Reamer 10 > 8mm 4 Reamer 12 > 9mm5 Reamer 16 > 10mm6 Allen key

1 Rod cutter handle2 Rod cutter handle3 Hammer (with soft ends) 4 Rod cutter5 Slap hammer extractor claw6 Slap hammer extractor weight7 Slap hammer extractor rod

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Modular Coned Hemi-Pelvis4.0 Operation instructions and guidelines

4.1 Pre-operative planningIt is important to assess the radiographs before the operation to establish that the device is suitable for the patient. It would also be beneficial to consider the fitment of the device with the acetabular cup and total hip replacement. The following recommendations and procedures should only be used for guidance and each case should be reviewed individually.

4.2 Recommendations for component selectionThe device is to be used with a suitably sized cemented acetabular cup. This could beplastic, ceramic or cobalt chrome. Cups with fins, spikes, studs, HA coated, or anythingelse which prohibits the fit or fixing using cement is not permitted and could have adetrimental effect on the patient such as loosening and excessive wear. The acetabularcup must be fixed to the coned hemi-pelvis shell using bone cement. The coned hemi-pelvis is available in four different stem sizes and one shell size. The shell size remains constant throughout the range and can accommodate a cup diameter of up to 50mm (outer diameter). The stem length for each device is 93mm. The reamer instruments provided with the kit are used as trials and match the stem size to indicate the overall positioning of the shell head. Reamers have been marked with a circumferential groove to indicate the centre of the coned hemi-pelvis shell.

Modular Coned Hemi-Pelvis4.0 Operation instructions and guidelines

4.3 Prosthetic insertion

– Resect the required length of bone. This is dependent upon the patient’s condition; however, the minimum amount of bone required for the device to anchor in a stable condition is 40mm.

– Select the correctly sized reamer and ream into the Ilium at the required angle so that the position of the acetabular shell will be as anatomically correct as possible. To avoid incorrect sizing, start with the smallest reamer.

– Reamers have been marked with a circumfencial groove to indicate the centre of the Coned Hemi-Pelvis shell.

– Once the Ilium has been correctly prepared, using the long impactor and hammer, insert the coned hemi-pelvis implant in the correct orientation.

– Added support can be provided by using the available Steinmann pins (cut down to the appropriate length using the rod cutters provided) and bone screws. The bone screws can fit in the holes of the coned hemi-pelvis shell. However, ensure that the screw head sits flush within the shell so that any cemented acetabular cup used will sit properly in the shell.

– It may be necessary to remove the device once inserted. In such an event, a slap hammer extractor has been provided and should be used. Assemble the extractor by placing the “rod” through the “weight” and screw the claw tightly. To remove the device, place the extractor claw over the coned hemi-pelvis shell and apply sharp but controlled pulls on the weight impacting against stop block to ease the device out. To avoid damage to the device, extractor or injury to the patient, the extractor should be used so that the pull is in line with but in the opposite direction to insertion.

– For the insertion of a cup, refer to the manufacturers’ surgical planning guide specific for that cup.

A

C

B

Coned hemi-pelvis inserted

Bone cement

Using bone cement, reconstruct the pelvis.

Level of resection

Steinmann bone pinsand bone screws for added support

B

C

A

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Coned hemi-pelvis Stem Ø9 > 7mm Length = 93mm mchp/Ø9 Ø10 > 8mm Length = 93mm mchp/Ø10 Ø12 > 9mm Length = 93mm mchp/Ø12 Ø16 > 10mm Length = 93mm mchp/Ø16 Steinmann bone pins (x3) Ø5mm Length = 300mm msp/300Ø5 Bone screws (x3) Ø4.5mm Length = 50mm mbscrwx/50Ø4.5 Ø4.5mm Length = 80mm mbscrwx/80Ø4.5

Modular Coned Hemi-Pelvis5.0 Parts and order references

Modular Coned Hemi-PelvisNotes

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QF125/1/M

AR

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