Principles
Foot
A little equinus is better than calcaneus
A little valgus is better than varus
A little varus is better than severe valgus
TA lengthening is most over used operation in CP
Knee
A little knee flexion is better than recurvatum
Knees
Problems
Tight hamstrings
- prevents knee extension with hip flexion
Often have co-spasticity with tightness of quads
- unmasked when lengthen hamstrings
- limit the amount of knee flexion in gait
- result in a stiff knee gait which is very energy inefficient
- i.e. must check Ely's / may need release of RF
Jump Gait
Issue
Knee flexed / equinus ankle
Non-operative Management
Botox / physio
Operative Management
Lengthen hamstrings at the musculotendinous junction
- release the Semitendinosis with tenotomy
- intramuscular recession of Semimembranosus
- usually leave biceps femoris
- aim for Popliteal angle of 70o
Stiff - Knee Gait
Spastic rectus femoris can cause limited flexion of knee during swing phase of gait
- particularly after hamstring lengthening
Operative
- Transfer of this to sartorius / SemiT
- release of rectus is just as good
- find plane of tissue under vastus intermedius
Tibia
Problem
Externally rotated tibia
Management
TDRO / tibial derotation osteotomy
- supramalleolar
- anteromedial approach
- DCP
Foot and ankle
Problems
1. Equinus
2. Equinovarus
3. Valgus
4. Hallux Valgus
Equinus
T Achilles lengthening may be the most overused operation in CP
- over-lengthening will lead to slumping in the patient with spastic hamstrings and hip flexors
- crouched posture / debilitating calcaneus
Operative Options
1. Formal Z lengthening / Zone 3 / tendon
- > 2cm lose up to 80% of power
- soleus important contributer to power
- soleus might not be tight
- Silverskiold test determines gastrocnemius tightness
2. Hoke triple percutaneous slide technique
- proximal and distal cuts medial
- middle cut lateral
- similar problems to above
3. Musculotendinous release (Zone 1)
- best procedures
- Baumann - multiple perpendicular divisions of aponeurosis of gastrocnemius +/- soleus
- Strayer - gastrocnemius recession / single transverse division of aponeurosis of gastrocneumius
Equinovarus
Cause
Tibialis posterior and T Achilles both tight
- most common in spastic hemiplegia
Options
1. Perform intramuscular recession
- never extramuscular procedure for fear of reverse deformity
2. Tibialis posterior split transfer to Peroneus brevis
- very effective and preserves plantar flexion
3. Hindfoot deformity fixed
- Dwyer lateral closing wedge osteotomy
- lateral calcaneal slide
Valgus Defomity
Preoperative
Always standing Xray of the ankle to ensure no ankle valgus as well
- Coby x-ray
Operative Options
1. Grice extra-articular subtalar arthrodesis
Results of the Grice are not very good
Scott etal JPO 1988
- 62 feet - 30% fail, 60% poor
- best in child 4-12 years
2. Evans lateral calcaneal lengthening + first MT plantarflexion osteotomy + T Achilles lengthening
- need first MT plantarflexion osteotomy to enable MT to touch ground post lateral calcaneal lengthening
- may need FDL to T Post transfer also
3. STJ Fusion
Hallux Valgus
Should always fuse
- high failure with anything else