IndicationsHip Fusion


Young adult 

- 16 - 30 years old

- monoarticular disease

- heavy demand 


Exhausted options of osteotomy

- risk of THA failure  / multiple revision surgeries considered too high


Aims of arthrodesis


Maximise bony contact

Minimise shortening

Provide rigid internal fixation

Compress the fusion site

Facilitate future conversion to THR





- difficulties in obtaining arthrodesis without femoral bone stock


Poor bone stock due other causes


Bilateral hip disease

- need ROM in other hip 90o

- in order to compensate in gait


Polyarticular disease eg Rheumatoid arthritis

- likely to develop hip / knee / back OA


Degenerative disc disease

- lumbar spine ROM important to compensate in gait and ability to sit in chair


Stiff ipsilateral knee or contralateral hip 




Good pain relief


No activity restriction

- most patients employed

- can return to normal jobs, even heavy labour

- most able to walk > 1 mile


Long term solution c.f. THA




Functionally inferior to THA


Increased stress on other joints


1.  Lumbar spine 

- 50% back pain

- most common reason for converting to THR


2.  Ipsilateral knee 

- 50% knee pain and instability

- increase rotation demanded in knee due to arthrodesis


3.  Contralateral hip

- has to compensate with increased ROM

- may predispose to OA

- will certainly worsen any underlying arthritis


Difficulties with certain activities



Supine sex


Sitting erect in chair

Difficulty putting on shoes


Gait abnormalities


Increased energy requirements

- increased oxygen consumption

- gait 50% less efficient


Increased lumbar lordosis to compensate 

- decreases stride length

- shortened stance phase

- contralateral hip has increased mobility compared to normal






To retain option of conversion to THR 

- don't use pelvic osteotomy

- preserve abductors




1.  Intra-articular

- most common

- allows disease to be addressed

- better correction of deformity

- difficult in paediatrics due to large amount of cartilage present


2.  Extra-articular


3.  Combined

- usually use combination 




Sagittal / 25° flexion

- <20° flexion - difficult to sit

- >25° flexion - difficult to walk due to LLD


Coronal / 5° adduction

- never abduction: can't walk, fall over even with 5° abduction

- too much adduction: LLD


Rotation / 15° ER 


< 2 cm LLD




Pseudarthrosis - 10% 



Methods to Increase Union


1.  Inter-trochanteric / subtrochanteric osteotomy 

- can increase union rate by decreasing lever arm of abductors

- come back 6/52 later and fix intertrochanteric fracture


2.  Vascularised bony extra-articular method

- iliac crest with Tensor Fascia Lata still attached

- the graft is inserted into trough in the anterior joint




1.  Lateral cobra plate

- detach GT

- pelvis to femur

- nil pelvis osteotomy


Hip Fusion Cobra Plate


2.  DHS

- Sunderland method


Hip Fusion APHip Fusion Lateral 2


3.  Anterior plating

- Smith Peterson approach


4.  Double plating

- anterior and lateral plate


Sunderland Method


Intra-articular approach /  2 hole DHS




Radiolucent table with II

- supine


Smith Peterson approach

- leave abductors intact

- dislocate hip anteriorly

- between sartorius and TFL

- between G medius and Rectus Femoris

- take off reflected head


Remove cartilage from head & acetabulum

- cup arthroplasty instruments useful

- approximate raw surfaces

- pack cancellous autograft

- position hip & hold with guide-wires temporarily

- place one guide wire central in head


Check position of hip

- need to be able to do intra-operative Thomas test

- FFD 25o / Add 5o / ER 15o


Fix with 150° DHS

- through joint into thick supra-acetabular area of ilium

- supplement with additional screws as necessary

- +/- Sub-Trochanteric Osteotomy


Spica at 2/52 for final position 

- NWB until xray union union


Schneider Technique 


Previously very popular technique

- don't use now as THR conversion not possible 


Characterised by pelvic osteotomy

- increases surface area for fusion

- pelvic osteotomy compromises future THR conversion


Femoral head compressed into osteotomised pelvis

- Lateral Cobra plate fixed to pelvis




Lack of head technique

- for post AVN or failed THR

- using a lateral Cobra plate & inserting the neck into the acetabulum


Lateral approach with GT osteotomy

- reflect abductors cephalad

- denude acetabular cartilage

- apply lateral cobra plate

- fix the GT to the arthrodesis with screws and place graft at the site

- +/- anterior plate


Britian Technique 


Extra-articular arthrodesis

- ischio-femoral arthrodesis

- oblique subtrochanteric osteotomy

- place tibial cortical graft from inferior femur to osteotomy in ischium

- medialize femur on graft

- spica


Results of Arthrodesis


Sponseller JBJS 1984 (classic report)


53 patients at 20 years post fusion

- average age 14 years

- back pain 60% / similar incidence back pain to general POP

- ipsilateral knee pain 40%

- contralateral hip 20%

- pain was unrelated to length of arthrodesis

- high functional abilities / played sport

- knee laxity of MCL was common 2° to hip excesssive adduction in fusion

- 15% conversion to THR (for back or knee pain)


TKR with fused Hip


Technically difficult

- have knee over edge of bed

- only way to get high flexion of knee for insertion tibial prosthesis


Poor results

- poor ROM


Best to revise arthrodesis first

- not if abductors not functioning


Conversion to THR



- back pain main indication

- ipsilateral knee pain

- contralateral hip pain 




1. Abductors 

- adequate function related to good outcome

- test by palpation preoperatively


2. Reason for fusion ?infection


3. Bony loss at acetabulum & femur


4. LLD

- average 2cm


5. Skin


6.  Higher failure than 1° THR




Good relief of LBP

- less so hip and knee

- most patients happy

- hip scores change little (owing to good results from arthrodesis)


LL equality achieved


Improved ROM


Gait poor for a couple of years

- related to abductor function

- intensive physio required



- 80% 10 year

- increased risk of infection