STJ Article Summaries Flashcards
Which articles support Root’s ‘normal stance criteria?’
- Root, 1966 ‘Axis of Motion of the STJ’ (Cadaver study)
- Bailey, 1984, ‘Subtalar joint neutral a study using tomography’
- Wright, 1964, ‘Action of the subtalar and ankle joint complex during the stance phase of walking’
Which articles refute Root’s ‘normal stance criteria?’
- Phillips, 2000 ‘The Normal Foot’
- Nester et.al. 2014, ‘Movement of the human foot in 100 pain free individuals aged 18-45: implications for understanding normal foot function’
- Kirby, 2001, ‘Subtalar joint axis location and rotational equilibrium theory of foot function’
Root, 1966, ‘Axis of Motion of the STJ’ (Cadaver study)
Method Aim Findings Reliability/ Weakness/ Reproducibility (repeatability of results & collection instrument) Level Paradigm
Method:
- Studied x22 cadavers
- Dissected feet, ligaments attached & inter cortical pins on talus, on bones to represent ROM
Aim: dispute Manter’s (1941) theory STJ screw like in nature & refine STJ axis of motion
Findings: STJ is hinge-like & tri-planar in motion (TP/ SP/ FP)
- STJ angled avg. 17° from SP & 41° from TP
- Agrees (w Manter) axis of rotation is perpendicular to plane of motion
- Lots of variation in data – the position of axis has lots of variation, altering function of joint
Weakness: cadavers- no muscles attached & pt. not alive, lacks external validity
Level 5- Observational study
Root paradigm
Wright, 1964, ‘Action of STJ & ankle complex during the stance phase of walking’
Method Aim Findings Reliability/ Weakness/ Reproducibility (repeatability of results & collection instrument) Level Paradigm
Method:
Motion between shoe & leg during the stance phase of walking analysed
(rotation about STJ & AJ axes)
-Previously believed motion of STJ & AJ was hinge like & joints had a simple axis of motion.
Found:
- STJ axis 10 degrees from SP & 45 degrees from TP
- In-toeing & out-toeing & action/tightness of triceps surae altered STJ & AJ motion
- STJ small, essential role in motion between foot & leg during stance
- STJ & AJ are interdependent & act as single mechanism in walking
Weakness:
- Only tested 1 person
- Level 5 - Observational Study
- No mention of validity or reliability (face validity present only)
Root paradigm/ supports Root theory
Bailey, 1984, ‘STJ neutral. A study using Tomography’
Method Aim Findings Reliability/ Weakness/ Reproducibility (repeatability of results & collection instrument) Level Paradigm
Aim: locate STJ neutral using tomography (validity of tomography)
Method: Tomographs taken of ankle, STJ (with calcaneus inverted/ everted) & STJ neutral (by talar congruency, as described by Root)
Findings:
- STJN position varies from person to person & left foot to right foot
- Not always found 1/3 from fully everted
- STJ Neutral = 2:1 ratio of inversion: eversion (of calcaneus)
- Location of the STJN position is variable in relation to total ROM available at STJ
Weakness:
- Small sample size x15ppl (males>females)
- Unknown method of participant selection
Level 5 study – Non-experimental, descriptive case study
Root/ Support’s Root’s theory
Kirby, 2001, Subtalar joint axis location and rotational equilibrium theory of foot function’
Method Aim Findings Reliability/ Weakness/ Reproducibility (repeatability of results & collection instrument) Level Paradigm
Aim:
-Propose new theory of foot function,
to improve existing podiatric biomechanics theory based on works of Root et al
- Theory based on spatial location of STJ axis, in weightbearing & rotational equilibrium in line with current research & clinical findings
- STJ rotational equilibrium theory
Findings:
-Externally created forces (GRF) & internally created forces (ligamentous & tendon tensile forces & joint compression forces) affect mechanical behaviour of foot
-STJ axis varies among individuals & has clinical implications
-Proposes that STJ is not thought of as one axis, instead many small axes that pass through the talocalcaneal joint
-Medially deviated STJ axis (internally rotated talus) = Excessive STJ pronation moments during weight bearing
-Clinical symptoms: plantar fasciitis, hallux limitus, abductor hallucis strain, second metatarsophalangeal joint capsulitis, sinus tarsi syndrome, posterior tibial tendonitis, posterior tibial tendon dysfunction, medial tibial stress syndrome, chondromalacia patellae & pes anserine bursitis
-Feet w lateral deviation of the STJ axis (externally rotated talus)
=Excessive supination moments during weight bearing
-Are less common
-Clinical symptoms: instability of ankle, inversion ankle sprains, & peroneal tendonitis
Central premise of the theory =
- The spatial location of STJ axis in relation to the osseous components of the foot, (altered by STJ rotation position & foot structure) affects pronation & supination moments acting across STJ axis during weight bearing
- Alterations in STJ axis (medial/lateral) = change motion of foot
Level 6 – Respectable opinion
Own paradigm/ Disputes Root’s Biomechanical theory
Phillips, 2000, ‘The normal foot’
Method Aim Findings Reliability/ Weakness/ Reproducibility (repeatability of results & collection instrument) Level Paradigm
Method:
Opinion piece based on historical descriptions a ‘normal foot’
Aim:
- Discuss problems assoc w determining what a ‘normal foot’ is
- Propose criteria to distinguish between normal and pathological foot
Findings:
- varies person to person & time period
- Suggests shoes create foot problems
- Each person has own definition of normal foot
- Human variation must be taken into account when treating
- Arch height does not equate to foot strength/deformity
- Root et al. in biomechanics book didn’t discuss all possible parameters or consider all foot types
Strengths:
- Further research is needed
- Takes human variation into account
Weaknesses:
- Articles not representative of all literature
- Expert opinion has little validity, low level evidence
- All references used are dated
Level 6 – Respectable opinion
Own paradigm, refutes Root’s hypothesis as doesn’t discuss all foot parameters of foot types
Nester, 2014, ‘Movement of human foot in 100 pain free individuals aged 18-45: implications for understanding normal foot function’
Method Aim Findings Reliability/ Weakness/ Reproducibility (repeatability of results & collection instrument) Level Paradigm
-understanding normal healthy foot needed to understand pathology & treatment interventions
Aim:
Address gaps in kinematic data from healthy feet (existing models based on theory)
Method:
Describe kinematics in x100 pain free ppl during walking
Results:
- Most movement in Saggital plane
- Least motion: between midfoot & calc
- Many different kinematic gaits & ‘normal’ symptom free foot types.
- Vary person to person
- Foot capable of many complex movements, not limited to supination/ pronation
- Data contradicts clinical concept: of ‘midtarsal joint locking’ in pronation to provide a rigid lever- all segments are compliant, not rigid lever
- kinematic data variation between ppl refutes ‘normal’ foot function
Level 5?
Refute/disagrees with Root’s theory
Jastifer, 2014, ‘The STJ: Biomechanics & functional representations in literature’
Method Aim Findings Reliability/ Weakness/ Reproducibility (repeatability of results & collection instrument) Level Paradigm
Aim: summarise biomechanical STJ concepts in literature
Method: Conducted literature review
Found:
- STJ important, difficult to study in vivo as few external landmarks
- Understanding clinically important
- Motion occurring at joint dependent on: anatomy, surface, axis, ligaments & muscles crossing joints
- Strong, low dislocation
-Action: PF & DF
& slight rotation abduction/adduction
Axis= 41 degrees from horizontal axis
& 16 degrees from 1st webspace (clinical landmark is talar head)
ROM: Ratio 2:1 of inversion: eversion
Manter believe screw & helix like in nature
- variation pt to pt clinically important
- transfer of tibial torque & force
- assessing rear foot alignment using goniometer unreliable, x-ray better
Level 6 - Expert opinion (author bias)
Root paradigm
