Floor Reaction Orthosis

Courtesy: Orthopaedic Principles ICL Kochi by Dr Hitesh Gopalan

FLOOR REACTION ORTHOSIS
A PIECE OF PLASTIC CAN DO WONDERS IF PROPERLY FITTED
– DR APJ ABDUL KALAM

ORTHOSIS :

AN ORTHOPAEDIC APPLIANCE / DEVICE DESIGNED TO CORRECT , PROTECT , SUPPORT OR ASSIST FUNCTION OF BODY PART

FRO is custom made orthosis made of polypropylene or carbon fibre reinforced polypropylene . It is used in quadriceps weakness.

Synonyms : Floor reaction orthosis /Floor reaction ankle foot orthosis / Ground reaction orthosis / Ground reaction force ankle foot orthosis .
Introduced by SALTIEL in 1979 , in India it was popularized by Prof P K SETHI and Prof S C LAKKAD in 1983 .

Components
• Full toe base (foot plate )in equinus (6 -8 degree plantar flexion)
• Uprights
• Anterior / pretibial/ knee piece

Combination of three components allow the plantarflexion -knee extension couple to occur

• FRO works in stance phase of normal gait cycle .
• In stance phase the load bearing axis lies in front of the ankle joint , knee joint and behind the hip joint .
• this is possible with the controlled flexion of knee joint and eccentric muscle pull by the quadriceps muscle .

Patient with paralyzed quadriceps , stance phase causes initial contact at heel , weight line to pass posterior to the knee axis , that causes buckling of knee .

Working principle :NEWTONS 3RD LAW

• Initial floor contact occurs at the forefoot as the FRO foot plate made with 5 to 8 degree plantar flexion . this will help the weight bearing axis to pass in front of the knee joint .
• Here the weight of the body over orthosis and over the ground is action.
• foot and orthosis absorb ground reaction forces which enter the body and keep the foot and knee straight .
• During the mid stance phase , the body brings the heel downwards , there is extension moment of prepatellar band pushing the knee backwards, which prevents buckling .

Indications
• Post polio residual paralysis -Most common indication
• Spinal cord injury
• Menigomyelocele
• Cerebral palsy
(Quadriceps weakness )

Wearing schedule : start with one hour on the 1st day and gradually increase with one hour daily , and by 2 to 3 weeks patient will be very much trained to use the FRO.

Usually it is worn over a stockinet or socks to prevent skin maceration. Patient can also wear shoes over the orthosis .

FRO works as a KAFO without a mechanical knee joint .

Patient can utilize his anatomical knee joint without buckling .

Highly complaint /cosmetically acceptable as it can be worn under shoes .

Disadvantages : custom made , skin irritations .

Limitations:
o Hip and knee FFD more than 10 degrees.
o Flail knee / flail ankle
o Angular deformities of foot , ankle , tibia , trunk imbalance .
o Minimum quadriceps strength of 2 +/3 –

Working tips :-

• Avoid using FRO with different shoes , as varied heel height affects stability .
• Ensure heel is properly seated inside orthosis
• Don’t immerse FRO inside water , just wipe dry .