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Triple Arthrodesis: PreOp Planning and X-rays

- PreOp Planning: 
- knee deformities should be corrected prior to any forefoot fusions; 
- stability of talus in mortise is necessary for successful arthrodesis; 
- determine if flexibility of forefoot and hindfoot; 
- if foot can be reduced to a satisfactory position then an in situ type of arthrodesis may be considered; 
- if hindfoot deformity is fixed & cannot be brought back to good position, corrective type of triple arthrodesis will be necessary; 
- varus hindfoot will usually have a compensatory forefoot valgus w/ plantarflexed first ray; 
- look for cavus type deformity 
- hammer toes may also be present; 
- dynamic hammer toe formation in cavus type of foot; 
- valgus hindfoot will usually be assoc w/ varus forefoot deformity to compensate, along with an abducted forefoot via hindfoot joint; 
- look for Achilles contracture w/ pronation deformity of the foot; 
- achilles tendon contracture is difficult to asses w/ fixed valgus deformity; 
- in the acquired flatfoot there may be an accentuation of midfoot collapse at midstance just prior to heel raise; 
- PreOp Xrays: 
- standing AP radiograph of both ankles
- look for calcaneovalgus impingement in acquire flatfoot as well as any valgus or varus deformities of ankle joint; 
- anatomic axis of tibia w/ ankle & hindfoot is evaluate; 
- standing lateral: - look for divergences of lateral talocalcaneal angle, & note "sag" sign of the foot at the talonavicular joint; 
- look for a stress frx of the fibula as a result of prolonged lateral impingment