Rubbing of the orthotic footplate upright against the malleolus can occur when placing the hinge too superior to the tip of the malleolus. The hinge movements then occur against the boney fragile skin of the malleolus, rather than at the inferior to the tip of the malleolus where there is no bone pressure. Solution: Always mark the malleoli of the patient prior to casting; make sure the marks transfer to the negative cast. Check the malleolar pivot location of the brace against the patient at time of dispensal.
Rubbing of the medial malleolus can also occur in severe pronation disorders where there is significant medial displacement of the distal tibia associated with closed chain midtarsal joint pronation-subluxation. Sometimes, the off-weight bearing negative cast technique fails to capture the true medial displacement of the tibia (and talus) which ultimately occurs with weight bearing. Also, when there is poor control of the foot and the foot slides laterally off the orthotic footplate there is an accompanying medial shift of the tibia and talus.
Solutions: Always perform a weight bearing assessment of the patient prior to casting. Determine if there is significant medial shift of the tibia. Note this on the special instructions of the Richie Brace orthotic prescription form. The lab can adjust the correction of the malleolar platforms to avoid brace rubbing.
When a patient develops rubbing after brace dispensal, carefully evaluate if the foot is sliding or pronating laterally off the orthotic footplate. The arch may be too high on the footplate, causing the lateral slide. Or the footplate may have poor conformity to the foot in a neutral position, loosing orthotic control. Check conformity of the heel, medial and lateral arches just as you would check accuracy of correction with any functional foot orthotic. Also, check the alignment of the footplate relative to the foot in the transverse plane.
In severe transverse plane subluxation, the footplate of the Richie Brace should be positioned in a more abducted alignment to the limb supports (malleolar postion). If not, the footplate will be abnormally positioned medially on the foot of the patient and poor conformity and control will result. If the lab is notified at time of original fabrication, the footplate can be positioned 15 to 30 degrees more abducted to the malleoli than standard required protocol.
Spot heating and adjusting the upright portion of the orthotic footplate can many times solve the medial malleolar rub. The heat should be focused on the segment just BELOW the medial ankle rivot. When the plastic becomes pliable, push the medial LIMB UPRIGHT downward, in a slight medial direction, forcing a slight bend in the orthotic plate medial upright. Hold for approximately 1 minute and then check to see if there has been adequate bending of the medial hinge section away from the patientâ€™s medial malleolus. If attempts at spot heating fail, the brace should be returned to the lab with instructions to expand the ankle width of the brace of correct any deficiencies in the footplate control.
Adding additional padding to the malleolar portion of the limb uprights does not usually solve irritation problems—this only increases the pressure against the malleolus. Finally, loss of pronation control can many times be solved by proper footwear prescription. Motion-control running shoes with medial posted midsoles and rigid shanks are recommended.
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