A study of in-shoe plantar shear in @entity1 with XXXX .

@entity1 @entity1066 @entity3949 @entity6
OBJECTIVE: To quantify in-shoe plantar shear in @entity6 feet. DESIGN: Plantar shear stresses are measured in a group of six @entity1 with a history of @entity6 . BACKGROUND: Although elevated pressure between foot and shoe frequently found in @entity6 @entity1 has been linked to a raised incidence of plantar ulceration, the shear component of stress at this interface is as yet unquantified. It is suggested that its effects may be equally damaging. METHODS: Measurements of shear were made locally beneath the medial four metatarsal heads and heel during unpaced gait in orthopaedic footwear, using a bi-axial magneto-resistive shear transducer. Similar methodology was previously employed on a group of asymptomatic adults, thereby allowing comparisons to be made. RESULTS: Overall the maximum shear stress for this @entity1 group (73 kPa) was not significantly different to that in the asymptomatic group (87 kPa). However the @entity1 group exhibited lower magnitudes of shear stress under the third/fourth metatarsal heads (average 51/39 vs. 86.5/71 kPa, respectively) and higher magnitudes under the first/second heads (73/64 vs. 35/31 kPa, respectively), indicating a medial shift. Step-to-step variability of maximum shear measured under the third metatarsal head showed an increase in the transverse component (coefficient of reliability 67% vs. 98%). CONCLUSIONS: Although the overall patterns of shear are broadly similar to the asymptomatic group, these pilot trials indicate a medial shift in shear loading under the forefoot coupled to increased step-to-step variability in the @entity6 group. RelevanceMechanical stress at the plantar interface between foot and shoe is of particular clinical relevance to the formation and management of @entity1066 in @entity3949 . Whereas the pressure component of stress is widely studied, the shear component is poorly described although it may be of equal importance.
