Neutral calcaneal stance position (NCSP)

Wikis > Biomechanics > Clinical Biomechanics > Biomechanical Assessment > Lower Limb Alignment > Neutral calcaneal stance position (NCSP)

Neutral calcaneal stance position (NCSP):
Patient is positioned in relaxed standing with feet in their angle and base of gait. The foot is manipulated into its NCSP by having the patient internally and externally rotate the legs while the head of the talus is palpated until it is equally prominent on the medial and lateral aspects (congruent). Both feet should be in the NCSP before measuring. The NCSP is the angle that the calcaneal bisection makes with vertical. Generally considered that it should be vertical or up to 2-3 degrees inverted. This has been traditionally assumed to be the position that the rearfoot should be in at the midstance phase of gait, as well as being assumed to be the most stable position for the foot

A vertical calcaneus is considered ideal, but there is nothing inherently stable about this position as the plantar surface of the weightbearing medial tubercle of the calcaneus is curved. What may be more important is the relationship of the contact point of the calcaneus relative to the subtalar joint axis.

Difference between NCSP and RCSP is a measure of how much the subtalar joint has compensated for a proximal or distal structural or functional variation.

If calcaneus is inverted more than normal  rearfoot varus, tibial varum, genu varum
If calcaneus is more everted than normal  rearfoot valgus

Reliability -

Clinical use:
• this position is the position that the foot is assumed to be in during midstance
• it could be considered as an ideal functional position for the foot to be in
• the aim of neutral position functional foot orthoses are aiming to hold the foot in
• as this position is usually written on the foot orthoses prescription form, so the orthoses lab knows which position the foot needs to be held in by the orthoses  need reliable measurement

Methods to improve reliability:
• accurate calcaneal bisection, careful placement of patient in subtalar joint neutral and accurate used of measurement tool
• after taking measurement, stand back and look – does the bisection look accurate, does the calcaneus appear to be inverted or everted the same amount that was just measured  may want to adjust up or down the measurement value based on this observation.

Common sources of error:
• may need to redraw bisection in a weightbearing position if skin movement changes position of bisection
• STJ not placed in its defined neutral position
• patient is not in angle and base of gait
• not measuring in the plane parallel to the posterior aspect of the calcaneus
• not placing both feet in NCSP before measuring

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