C Approach and Implant Removal

Pre-operative Planning

CT / quantify bone loss

X match 4 units

Cell saver

Anaesthetic review

Bone graft (cortical, cancellous)

Component removal gear

- extraction gear for femur / liners

- cement removers for cemented femur

- curved osteotomes for cemented cup

- X-plant for uncemented cup

Revision long stem femoral implants

Revision acetabular implants including cages

Exposure

Posterior approach

- often easiest in revision

- good for ETO

Recreate fascial and muscular layers

- aids exposure and closure

Wide exposure of hip joint

- removal of all pseudocapsule

- expose entire proximal femur & acetabulum

Extended Trochanteric osteotomy

Concept

Osteotomy lateral 1/3 to 1/2 of trochanter / femur

- posterior to anterior longitudinal cut

- short distal transverse cut

- levers / hinges open anteriorly

- maintains anterior vasculature / muscle attachment

Indications

1. Aid exposure

2. Removal cement (especially infection)

3. Removal well fixed uncemented prosthesis

4. Removal cement plug / bone very poor / risk of perforation high

5. Abnormalities of the proximal femur

Contraindications / Relative

1. Impaction bone grafting

2. Cementing revision prosthesis

Technique ETO

Length

- measured from tip GT

- 2 – 15 cm long

- need to preserve diaphysis if using distal press fit uncemented stem

Timing

- usually after implant removal

- may not be possible

Site

- elevate vas lateralis forward

- expose linea aspera

- expose posterior femur

Osteotomy

- use drill holes to mark osteotomy

- drill both cortices

- thin oscillating saw

- cut down through anterior and posterior femur in line with GT

- through both cortices

- transverse cut distally through 1/3 diameter

- lever open

Fixation

- 3 x cerclage cables, tension

- protect sciatic nerve

- submuscular

Results

98 – 100% union rate by 6/12

Removal Femoral Implant

A. Cemented

Initially

- must clear shoulder of prosthesis

- must ensure no GT overhang or will fracture on removal

Extraction devices

- stem often easily removed if cemented

- extraction devices hook around proximal prosthesis & backslap

- can release cement – implant interface

- combination flexible osteotomes, micro sagittal saw, small burr

Cement removal

- aided by ETO

- use arthroscopy light down femur

Cement removal kit

- flexible osteotomes, reverse hooks, cement splitters

- split cement radially & then removed

- can use high-speed burr

- may require distal window

Removal of cement plug

- remove proximal cement

- drill guide in centraliser

- insert tap, then extract

Need to be very careful to avoid inadvertant perforation

B. Uncemented

Can be very difficult to remove a well fixed stem

- i.e. if removing for infection

Consider component design

- proximally coated

- extensively coated

Breakdown osseointegration

- flexible osteotomes

- sagittal saw

- very difficult

- can perform ETO about stem

Extraction devices

- company specific

- hook under neck

Broken Stems

- stem is invariably well fixed distally

- osteotomy to site of fracture

- +/- distal window

Acetabulum Removal

Acetabular revision only

1. Leave femoral component in situ

Indications

- femur not loose / damaged / good orientation

- need to be able to match new cup / poly to femoral head

Technique

- can remove head if modular (use company device to lever off)

- make anterior pocket for femoral stem

- protect trunion with swab

Note

- can be a problem putting a ceramic head on an old trunion

- if needed, can get a ceramic head with a metal liner for trunion

2. Removal of cemented Femoral component / Re-cement a smaller prosthesis into a well fixed cement mantle

Revision Cup Only Cement in Cement Femur Pre

Removal

- as above

Re-cement prosthesis

- ensure cement mantle clean and dry

- trial small component

- cement in cement revison with high viscosity cement

- insert cement when very viscous

- put in new prosthesis very early

Removal Cemented Acetabulum

Technique PDF

Technique PDF 2

1. General principle is to loosen poly cup from cement

- do so with curved gouges

- between cement & cup

- cement then removed piecemeal

2. Can simply ream out the poly

3. Insert threaded extractor through drill hole in poly

- then disimpact poly from cement

Uncemented Acetabulum

Options

- may just be changing liner and leaving cup

- may need to remove well fixed cup i.e. infection

- may be removing loose cup

Liner

1. Company specific removal instruments

- need to disengage locking mechanism

2. Simply lever out liner with osteotomes

3. Drill hole in liner 4.5 mm

- insert 6.5 mm screw to push liner out

Metal Shell

1. Curved osteotomes

- risk bone loss

2. Zimmer Explant Acetabular Removal System

- 3 sizes depending on implant size

- central head to sit in liner

- must remove screws first, then replace liner

- diamond blades cut between cup and bone

- initial blade short

- second is thin and full radius