Subtalar Neutral Assessment and Orthotics PDF

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PHTR 616 Adulthood & PT Practice I
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Subtalar Neutral Assessment and Orthotics 12/1/18 

One of the key things when you’re doing a foot assessment to know whether it’s compensated/uncompensated is subtalar inversion/eversion o If you have subtalar (ST) eversion then you can always compensate o If you don’t have eversion there, you can’t compensate  You will have to measure ST inversion/eversion to know whether its compensated/uncompensated

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Alignment- Tibial Torsion Test- Sitting

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 Often just eye-balled. Want to know where pt is starting out in NWB position Sit with knee flexed to 90 degrees. Place thumb of one hand over the apex of one malleolus and the index finger of the same hand over the apex of the other malleolus.  Tibia is usually ER, will always see a rotation Visualize the axes of the knee and of the ankle.  The lines are usually not parallel but instead form an angle of 13-18. 13-18 of lateral tibial torsion normal.  Anything greater is excessive ER of tibia  May see toe-out position in standing but may not be because of the tibia  Ante/retroversion o May come from the hip or tibia  Pronated o (+) Toe sign

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Alignment: “Too Many Toes” Sign

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Observation- Feiss Line  Mark medial malleolus, navicular, 1st MT. o Mark apex of medial malleolus and plantar aspect of the 1st MTP joint in NWB. o Palpate navicular tuberosity and note where it lies relative to a line joining the 2 points. o Patient stands with feet 3-6” apart. o Navicular tuberosity is palpated. o Normal- navicular lies on or close to the line joining the 2 points. o

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Patient stands in a normal relaxed position. Examiner views from behind and counts how many toes they see (always looking at affected vs non-affected side) More toes are seen on the affected side if: 1. Heel is in valgus 2. The forefoot is abducted 3. Tibia is rotated laterally more than normal. 4. Could be seen with hyper pronation if talus is positioned in neutral, calcaneus is in neutral, forefoot adducted on the rearfoot.

If when they stand (performed in WB position):  1st degree flatfoot  Navicular falls 1/3 the distance to the floor.  2nd degree flatfoot  Falls 2/3 the distance.  3rd degree flatfoot  Rests on the floor.

Gait Cycle (6:27)  The foot needs to be rigid (push-off) sometimes, flexible (uneven terrain) other times o Heel Strike  The foot is in a supinated position and immediately begins to pronate when going from heel strike to weight acceptance. o Pronation  Results in increased foot mobility to adapt to uneven terrain and absorb ground reaction forces.  Want to adjust to uneven terrain

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Subtalar Joint- Finding Neutral (8:23)

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Maximum pronation is reached at the end of weight acceptance (midstance) and the foot supinates from midstance to toe off (that’s when you need a more rigid foot) Supination  transforms the foot into a rigid level arm needed for propulsion.

Patient prone figure 4 position  Helps align tibia Examiner grasps foot over the 4th and 5th metatarsal heads with the index finger and thumb of one hand (outer hand).  With inner hand, come anteriorly on talus and palpate to see where subtalar neutral is  Supination  Will feel head come laterally  Pronation  Will feel head come medially The examiner palpates both sides of the talus on the dorsum of the foot, using the thumb and index finger of the other hand. The examiner then passively dorsiflexes the foot until resistance is felt. While the foot is dorsiflexed, the foot is moved back and forth through an arc of supination (talar head bulges laterally) and pronation (talar head bulges medially).  The foot is positioned so the talar head does not seem to bulge on either side.  STN: No bulging on either side  In STN, never find a rearfoot valgus  Normal is 2-8 varus, greater than 8 is abnormal

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Rearfoot Alignment (the angular relationship between the bisection of the calcaneous and the bisection of the lower 1/3 of the leg)

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Forefoot Alignment

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Prone figure 4 position. Examiner places mark over midline of calcaneus at the insertion of the Achilles tendon. Examiner places second mark approximately 1 cm distal to the first mark as close to the midline of the calcaneus as possible.  Calcaneal line is then made to join the 2 marks. (11:12) Examiner makes 2 marks on the lower 3rd of the leg in the midline. These 2 marks are joined to form the tibial line. Subtalar joint is held in neutral and the examiner looks at the lines Normal  Slight varus 2-8 degrees. Rearfoot Varus deformity  Greater than 8 degrees

Prone figure 4. (11:59) Position foot in subtalar neutral  Holding the 4th & 5th MT Examiner pronates the midtarsal joints maximally and then observes the relation between the vertical axis of the heel and the plane of the 2nd through fourth metatarsal heads.  Look at the relationship of the forefoot to the rearfoot

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If the medial side of the foot is raised- forefoot varus.  1st metatarsal head is up If the lateral side of the foot is raised, forefoot valgus.  1st met down, 5th met up= valgus If all the MT heads are going straight across, that’s a normal foot alignment for the forefoot  These terminologies are important to understand when you are trying to figure out what to do with an orthotic (13:59)

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Alignment: Neutral Position of the Talus (weight-bearing position) o Patient stands with feet in relaxed position.  See where navicular is and see how much it drops o Examiner palpates head of talus on the dorsal aspect of the foot with the thumb and forefinger of one hand. o Patient then pronates and supinates foot slowly and foot is positioned so that the talar head does not appear to bulge to either side. o Can measure how much the navicular drops from subtalar neutral to relaxed position.  Any measurement greater than 10 mm is considered abnormal.

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Normal Foot Structure o Lower limb vertical on WB. o The calcaneal condyles are flat on the ground and the calcaneus is in a vertical position. o The metatarsals are in one plane. o The forefoot to rearfoot relationship is such that the plane of the metatarsal heads is perpendicular to the bisection of the calcaneus. (16:23)

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Weight bearing Observations

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o Pronatio n

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Supinati on

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Forefoo t varus  M e d i a l

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Forefoot valgus  Lateral side up

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Range of Motion and Mobility Measurements o Calcaneal inversion o Calcaneal Eversion o First Ray Mobility o First Ray Position (PF or DF) o 5th Ray Mobility

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Calcaneal Inversion and Eversion  Important to look at to see if it’s compensated/uncompensated o

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Calcaneal Inversion (bisect calcaneus, bisect middle of leg)  Normal ROM: 25-30  Level gait: 12  Uneven terrains: 15  Sport activities: at least 20  If you don’t have pronation, foot cannot get medial condyle down on the ground (need eversion). If you don’t have eversion, can’t have compensation Calcaneal Eversion  Normal ROM: 0-5  Restricted or negative values constitute an uncompensated rearfoot varus deformity.  Normal or positive values constitute a compensated rearfoot varus deformity 

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Ex: You have pt in STN in prone & they have >8 of varus so they have a rearfoot varus. o How do you know if it’s compensated/uncompensated? Look at calcaneal inversion/eversion.  If they have enough eversion, then they can compensate.  With a varus foot, the medial part of the calcaneus is going to be a little up but you could have some pronation (that’s what’s going to bring the medial condyle down)

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Foot wants to have the most surface area (everts)

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Compensated Rearfoot Varus o There is enough eversion to compensate o At heel strike, the calcaneus excessively everts (pronates) to bring the medial calcaneus flat on the ground (22:14)  Everts to get it down o The eversion remains excessive throughout stance phase, resulting in a hypermobile foot.  May not have enough rigidity o Symptoms:  Callus under 2nd MT head  Land on the outer part of that calcaneus (eversion) & foot pronates in a fast way & hits 2nd MT  Posterior tibial tendonitis  Plantar fasciitis  Affects arch if you go into “flat foot” over & over  Achilles tendonitis  Constant movement there could aggravate Achilles  Patellofemoral pain  Change foot position & see how it affects their knee position & pain

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Uncompensated Rearfoot Varus (24:39) o There is excessive calcaneal inversion with restricted calcaneal eversion at the STJ. Not enough eversion available.  Pt does not have enough eversion o In order to bring the medial calcaneal condyle flat on the floor, the MTJ will become increasingly hypermobile (midfoot) over time. Therefore, need to post more aggressively. o The first ray may want to PF down to attempt to improve medial loading o Symptoms:  Retrocalcaneal bursitis  Haglunds syndrome  Callus under 5th MT  Landing on outer part of foot & then trying to come down  PF first ray  Inversion ankle sprains  If they don’t have enough eversion  Excessive MTJ pronation

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Compensated Forefoot Varus (26:38)

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If you have a forefoot varus and you don’t have anything rearfoot, when the heel strikes the ground, everything is going to be fine No problems at heel strike, but in order to get the forefoot flat on the ground the STJ must pronate excessively.  Medial part will be up  Pronation at subtalar joint to get it down This pronation continues throughout the stance phase with a resulting hypermobile foot throughout propulsion. Forefoot is usually abducted (positive toe sign). Arch is usually low. Symptoms:  Callus beneath the 2nd and 3rd MTHs  Toe deformities (HAV, bunions, hammer toes, claw toes)  Patellofemoral pain  Neuromas  Hypermobility puts strain on nerves and tissues there  Metatarsalgia  Piriformis syndrome

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Uncompensated Forefoot Varus o The STJ cannot adequately compensate (pronate) to allow the medial forefoot to contact the ground.  Medial aspect up but don’t have enough pronation to bring it down (not enough calcaneal eversion) o The lateral aspect of the forefoot is subjected to excessive ground reaction forces. (can’t pronate to bring it down) o A lot of strain on the 5th MT o The 1st ray often plantarflexes  Tries to get foot flat o Symptoms:  Callus beneath the 5th MTH  Fractures of the 5th MT  Lack of shock absorption at heel strike  the 1st ray and MTJs may pronate to achieve forefoot contact, causing dorsal MTJ pain

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Compensated Rigid Forefoot Valgus o The medial aspect of the forefoot loads excessively at foot flat and the lateral side of the foot is lowered to the ground via compensatory STJ supination.  As you go on you are not going to see an uncompensated forefoot valgus because when the forefoot is in valgus, the lateral part is up more so you need to supinate; calcaneal inversion. Everyone will have enough calcaneal inversion to compensate

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This produces supination too quickly in the gait cycle, resulting in a rigid foot that has difficulty adapting on uneven terrains. Arch is usually high on weightbearing. Plantarflexion of the 1st ray may mimic a forefoot valgus. Symptoms:  Callus beneath the 1st and 5th MTH  Inversion sprains (supinated positions)  Difficulty adapting to uneven terrain

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Plantarflexed First Ray (33:24) o Normal 1st MTH position should lie in the same plane as the lesser metatarsals. o A plantarflexed 1st ray deformity is positioned below the plane of the lesser MTHs and allows the 1st MTH to move a longer distance below than above the plane of the lesser MTHs. o Functions like a forefoot valgus deformity if it is a rigid plantarflexed 1st ray  If it’s down further than the rest, see if it moves up. If so, it is flexible. When you put weight on it, it will move where it should be. Over time if it’s rigid/stuck down, then you can imagine the outer part is going to be up (valgus) then your body will be doing the same thing to compensate (will see it as a forefoot valgus)

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Compensated Plantarflexed 1st Ray o If the PF 1st MTH is flexible, then the foot will function as if it were not present on weightbearing. o If the PF 1st MTH is RIGID, then the foot will function as a forefoot valgus on weightbearing. You will see early loading of the 1st MTH and compensatory STJ supination. o Symptoms of a rigid PF 1st ray:  Same to those of a rigid forefoot valgus

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Goals of Orthotic Intervention (35:10) o Control the velocity of pronation. o Redistribute plantar pressure. o Support abnormal structural forefoot positions which lead to abnormal rearfoot function in stance o Support abnormal rearfoot deformities which cause excessive STJ pronation. o Improve calcaneal position at heel strike. o Reposition the subtalar joint in neutral position just prior to heel rise. o Fully pronate the MTJ, when the STJ is in neutral, in order to lock and stabilize the foot, converting it into a rigid lever for propulsion.  This is why you need orthotic intervention (stable/flexible when it needs) o Allow normal plantar flexion of the 1st ray, stabilizing the forefoot in response to the retrograde ground reaction forces sustained during propulsion. o Provide for a normal degree of contact phase shock absorption.

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General Principles of Posting o Post what you see (rearfoot and forefoot) o Varus deformities are posted medially (rearfoot) o Valgus deformities are posted laterally (forefoot)  Can’t be valgus @ rearfoot o Degree of posting:  Small  0-2  Medium  3-4  Large  5 or more o

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Calculating rearfoot deformity:  STN rearfoot varus minus normal amount (4 degrees) (example: 10 deg-4 deg= 6 degrees of pathological varus)  A 50% correction is a good place to start  If you post the rearfoot more than 3-4 you will need to add forefoot posting even if no forefoot varus deformity exists. If not, the orthotic will “wobble” If a forefoot varus is present and the rearfoot is neutral, and a 1 rearfoot post to stabilize the STJ

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Posting Examples (38:17) o Rearfoot varus:  in rearfoot you are posting medially  Medial condyle is resting on the orthotic so our foot doesn’t have to do all these crazy things to get the medial condyle down because it’s just resting on that orthotic. o Compensated Rigid Plantarflexed First Ray (RCS):  Acts as a forefoot valgus (lateral side up)  Post in the forefoot on the lateral side so the whole foot doesn’t have twisting down into that supination to contact (getting contact with orthotic) o Forefoot valgus:  Post laterally to accommodate it

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A comparison of different over-the-counter foot orthotic devices on multi-segment foot biomechanics o Compared 3 different types of OTC foot orthoses (SOLE, SuperFeet, and Powerstep)

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Custom Orthotics

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Prefabricated example- OrthoFeet Customized Arch Support

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All over-the-counter devices exhibited significant decreases in plantar fascia strain compared to no orthotic Powerstep exhibited significant decreases in peak rearfoot eversion Over-the-counter orthoses are a cost-effective alternative to custom-made devices

Unique bladder design, filled with polyurethane foam and cushioning Gel, dynamically shapes to the contours of the foot. It provides customized support and alleviates discomfort and fatigue off your feet, all the way up your knees and low-back.

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Comparison of custom and prefabricated orthoses in the initial treatment of proximal plantar fasciitis. o The percentages improved in each group were: (1) silicone insert, 95%; (2) rubber insert, 88%; (3) felt insert, 81%; (4) stretching only, 72%; and (5) custom orthosis, 68%. o When used in conjunction with a stretching program, a prefabricated shoe insert is more likely to produce improvement in symptoms as part of the initial treatment of proximal plantar fasciitis than a custom polypropylene orthotic device.

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Stride Orthotics- 24 Foot Types-Quadrastep System

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Stride Orthotics- 24 Foot Type Algorithm o The "24 Foot Types Algorithm" is a clinical algorithm identifying 24 unique foot-types. These 24 foot-types are subdivided into 6 groupings of 4, known as “quads.” Each quad has its own very specific foot and gait characteristics. A patient’s foot-type (quad-type) influences not only their gait, but the conditions that may afflict them throughout their lives. This modern theory takes into consideration the clinical impact of these foot types on foot biomechanics, muscle function during gait, and how the mechanics of each foot type can predict a patient's predisposition to particular musculoskeletal pathologies. This assessment is based on the examination of pathological gait conditions, resulting from the occurrence of rearfoot varus deformities (compensated and uncompensated), forefoot varus and forefoot valgus deformities, as well as their combined effects.

Foot Type A- Severe Pes Cavua Foot

Type B- Mild Pes Planus Foot Type C- Neutral

Foot Planus

Foot Type D- Moderate Pes

Foot Type E- Abductovarus Forefoot 12

Foot Type F- Severe Pes Planovalgus

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