16 - Equinus Flashcards
What is equinus?
- Definition of muscular gastrocnemius or gastro-soleal equinus is limitation of dorsiflexion due to tight posterior muscle group
- Who knows? 5 /10/15/20 degrees beyond 90
- Consensus among the majority of experts is that at least +10 degrees of ankle dorsiflexion with knee extended is needed for normal gait with limited foot compensation
o 3-15 deg with knee extended and 10-20 deg with knee flexed is the range of reported normal dorsiflexion (Schweinberger, 2008 LOE 3)
Etiologies
- Congenital (most common)
- Developmental - Achilles tendon shortens as a result of another pathology
o Pronation, tarsal coalition, internal malleolar position, limb length, etc. - Acquired – trauma or casting
Pseudo equinus
- Actually have 10º of dorsiflexion at ankle, but functionally need more because of a plantarflexed forefoot
- Forefoot loads earlier due to anterior cavus foot
**Osseous equinus **
- Osseous impingement of the tibiotalar articulation
- Abrupt end to dorsal ROM
- Not dependent on knee position
- Radiographs will reveal an osseous block
- Charger radiographic view
How do we assess for dorsiflexory ROM to identify if equinus is present?
Multiple ways described in the literature: NWB and WB
- Neutral / Supinated appears to be the most accurate and reproducible*
- Pronation of the foot increases the measured DF by more than 10 degrees
- This perceived DF does not represent ankle movement
How do we test for equinus? (review)
- Landmarks are the lateral margin of the foot and the midline of the lateral calf
- Must evaluate from the lateral side
- Must avoid pronation of the foot
- Holding the foot Neutral to Slightly SUPINATED/varus is the most accurate and reproducible way to measure ankle DF (Molund et al, 2014)
- Patient must be relaxed and not fire anterior muscles- if they are results in reflexive inhibition of the gastroc-soleus complex (Chen & Greisberg 2009)
Examination
Clinical Exam: Silfverskiold Test
o Assesses for change in dorsiflexion with knee extended
Annrow et al (FAI, 2006)
o Cadaveric study that showed that both isolated gastrocnemius contracture and triceps surae contracture showed similar shift in wt bearing forces from hind foot to forefoot.
o Should the Silfverskiold exam dictate surgical procedure performed?
o Does it matter? Change in strength of IGR vs G-S R? Literature Unclear
Reliability of examination
- Mixed findings in the literature: possibly due to technique, positioning?
- Mooseley et al, 1991: Good inter and intra-rater reliability
- Ensure the same landmarks and technique are used
- Goniometer may not be the most reliable
- Does it matter if the difference is statistically significant if it is not clinically significant?
- Bigger question may be is equinus present or not- not to what exact degree
Equinus and gait resultis in
o More rapid entrance and exit into and out of mid-stance
o Reduced step length
o Slower walking velocity
o Increased forefoot pressure - leads to ulcer in diabetics
o ***Pronation of foot to obtain required dorsiflexion
Most common limiting factor is tight Gastroc or Gastroc-Soleus Complex
**Compensatory mechanisms – these are important, be comfortable with this list **
- Forward torso lean
- Pelvic rotation
- Hip Flexion
- Knee hyperextension
- Knee flexion (Chimera, You)
- External rotation of leg
- STJ & MTJ (oblique axis) Pronation
o Dorsiflexion of forefoot on rear foot compensates for the lack of ankle joint dorsiflexion
o This abnormal amount of motion in the foot leads to tendon, ligament and joint degeneration
Pathologic conditions often due in part to compensation for equinus
- If we have pronation due to equinus, there will be a higher incidence of the following
o First Ray hypermobility- HAV with MPAV (Hallux Limitus)
o Hammertoes
o Plantar Fasciitis
o Flatfoot deformity
o Metatarsalgia/Capsulitis
o Patello-femoral syndrome
o Overuse Syndromes (Stress Fractures, tendinopathy)
o Postural Fatigue
A LOT OF POTENTIAL COMPLICATIONS – this is why you need to be assessing for it
Treatment for equinus
- Conservative
- Surgical
What is the clinical outcome with a stretching protocol to treat equinus?
There is no consensus on how much and how often to stretch for equinus
Grady & Sexena STUDY
o Looked at the effect of time spent stretching (0.5, 2.0, 5.0 min/day) for 26 weeks.
o Contralateral limb control
o **No significant difference in time vs amount of dorsiflexion gained.
o 5 min group was closest to significance
Tendons are NOT going to respond well to stretching
o They can help with symptoms, but will not improve the pathology
Does stretching increase dorsiflexion?
o Stretching had a statistically significant effect on increasing ankle joint dorsiflexion.
o Reported increases of 2-8 deg of dorsiflexion
Conclusions on stretching
None of the studies report magnitude of increase in ankle dorsiflexion to produce clinically significant improvements in function.
o Minimal clinically important difference for ankle dorsiflexion ROM has not been established.
Due the brevity of the study periods (the longest study was 8 weeks), it is difficult to ascertain for how long conservative treatments may remain effective.
