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Awkward swing phase biomechanics

Discussion in 'Biomechanics, Sports and Foot orthoses' started by Simon Spooner, Oct 1, 2008.

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    Yesterday I saw a 39 year old female who 3 years ago was training for a marathon and found herself scuffing the floor- she put it down to a change in shoes. She completed the marathon. Since then, she's had a raft of tests: nerve conduction, EMG, MRI to lower spine all of which have detected no abnormalities. They've given her anti-epileptics, and MS medication- these just made her feel ill. No familial history. Manual muscle
    testing for strength and length revealed nothing of note other than slight
    weakness of extensor digitorum longus- this was bilateral though. In fact
    everything you would predict should be tight or weak wasn't!! No obvious
    muscle wasting, No limitation in joint motion. Slight LLD R> L approx. 5mm. Neurological testing revealed no abnormalities except her balance is rubbish- on both legs! She is generally pain free- occasional lower back pain.

    Craig will post a link to a video of her gait, your thoughts are invited.

    Thanks Craig.
  2. admin

    admin Administrator Staff Member

    Thanks Simon....to see the video, right click here to download - use 'Save'. This will download a zip file, that the video is inside.
  3. Simon:

    The left side looks like not only swing phase is abnormal but also the propulsive phase is shortened, causing her to have an antalgic gait, favoring the left side. In other words, stance phase appears shortened on left versus right side due to less propulsive gait pattern on left.

    It also appears that the hip may be dropping on the left side, which would require a video of her hips to confirm this.

    The knee appears to rapidly externally rotate at heel off which may be causing the foot to also abduct rapidly after heel off, nearly like an abductory twist.

    Does she have symptoms? Where are they? How is ankle joint dorsiflexion and STJ axis position? Any detectable asymmetries other than possible LLD??

    This is an interesting gait pattern.
  4. David Wedemeyer

    David Wedemeyer Well-Known Member


    She appears to have a mild Trendelenburg gait on the left, more of what I would expect to be a "sign" rather than true Trendelenburg gait of course.

    Have her stand balanced on one leg at a time with the other knee flexed and watch the pelvis for a few seconds. If the unsupported side pelvis drops she may have gluteus medius weakness/lurch. I believe that Kevin is onto something here suggesting that the left hip may be dropping.

    If there is palpable tenderness just lateral of the greater sciatic notch,
    I would direct attention to the superior gluteal nerve. Piriformis syndrome is one culprit especially if she is one of the lucky few who's SGN passes through the belly of the piriformis muscle.
  5. I agree with you evaluation of the video. She has no symptoms other than occasional back ache- this does not trouble her really, What she wants to know (and me) is why has she stated to walk like this- what's causing it? Ankle joint dorsiflexion shows no restriction, STJ axis (static) is normal L, very slightly more medial on right in standing, non weightbearing no real difference. But dynamically the oblique propulsive strategy on the left is likely to result in laterally deviated STJ axis.
    Last edited: Oct 2, 2008
  6. David, I've already done this and there was no obvious Trendelenburg sign in static assessment but there is a slight drop in gait. My experience of piriformis syndrome is that it's painful and or areas of numbness- she has no pain or numbness. I'll try and capture some more video of whole body and post it.
    Last edited: Oct 2, 2008
  7. efuller

    efuller MVP

    Hi Simon,

    What is the wear pattern on the tip of her left shoe? Is the rotation of the knee occuring with the toe on the ground or just after lift off?

    It could be she is initiating swing with a hip flexor that also acts as a thigh external rotator. Maybe an internal rotator is weak. I'd agree that the left is much less propulsive than the right so there would have to be more "hip pull" on the left.

    Is the balance bad because of sensory or motor?

    Just a coupld of thoughts,

  8. Sammo

    Sammo Active Member

    Hi Guys,

    Thought I'd try playing with the big boys for a little while.. :eek:

    A couple of observations from me, please feel free to shoot me down in flames if what I say is complete B******s.

    It appears to me that the fast external rotation is happening on the left leg just after the toe leaves the floor. The left leg looks like there is some neurological deficit, as I think there appears to be an ever so slight foot drop. The left side appears to have a shorted stride length and an earlier heel lift (as has already been mentioned), which could be due to shorter calf muscle or less muscle power?

    Could the ext rotn be a compensation to avoid the foot dragging on the floor, with the amount of running she has done, is it possible she has retrained her gait to this effect?

    Also, a video of the hips would be nice, it appears there is lots of movement of the pelvis in the transverse plane on the left side.. could there be lack of hyper extension in the left hip? This could be a possible reason for the shorter stride length.

    Ok, enough from me.. I'm gonna put my head back below the parapet and remain quiet for another six months!

    Sam Randall
  9. I like what Sam said.

    Seems to me that the foot is struggling to clear the floor, then flicking inward rather more than is ideal. Hard to be sure but i wonder if the tib ant is fireing late and the EDL late or not enough (or at all!) . I do wonder if there is a problem with the activation of these muscles.

    None of which fits because of course this should have sowed up on an EMG! unless the problem is sporadic. Could it be that the tests were carried out at a time when it was less of a problem (for eg if the nerve compression in the spine was less severe that day).

    Always a tough one when the tests don't match what you seem to see in vivo. Either your observations or the tests are wrong, which do you trust?

  10. Gentlemen,

    Thanks for your input so far. I've just taken another look at the patient and checked and re-checked on the basis of comments so far:

    Piriformis- painless on palpation, no history of pain in this area or referred sensory symptoms.

    Trendelenburg- I've added video of pelvic motion to You tube and will post the links when they've finished processing... You can make you own minds up.

    Manual testing suggested slightly weaker left hip abduction- strengthening exercises given.

    Ankle dorsiflexion, initial testing pt. said left felt tighter, however upon re-test with goniometric measurement no difference in ROM both approx 10 degrees.

    STJ axes see picture attached.

    Hip flexor strength normal both sides.

    I too felt there was some foot drop- much easier to see playing the video through motion analysis software and was considering an AFO. I've trialled one on the patient and she feels it makes her more stable. However, all of the neural tests she has had showed no abnormalities. This included EMG nerve conduction and brain MRI. She has seen a physio who has given her strengthening exercises for ext digitorum longus- manual muscle testing showed slightly weak (was able to dorsiflex against resistance), but in my view this was bilateral.

    Rotation appears to occur just after toe off, there is an oblique propulsive strategy (low gear) followed by rapid rotation once the foot leaves the ground.

    No difference in hip extension on static testing.

    Cheers Y'all.

    Attached Files:

  11. Robert, you posted this as I was writing my latest post. I think EDL may be significant but I just can't work out why the EMG and nerve conduction studies didn't show anything here. Manual testing suggests it is a little weaker than it perhaps should be, but there is no obvious loss of muscle bulk and she can dorsiflex the lesser toes against resistance- all she needs to do in swing is dorsiflex against gravity- right? Next question- what's causing this?

    P.S. I just received a message from patient requesting an AFO.
  12. Griff

    Griff Moderator


    As an alternative to the AFO do you think your patient would benefit from a Richie Dynamic Assist Brace?

  13. Simon:

    I have seen other patients have unilateral weakness in their extensors when the NCV/EMG study comes back normal. Like you, I wonder how this could be the case. Maybe a false negative for some reason??? Could the tendon be damaged?

    The extensor weakness on the left could certainly explain the gait findings. Normally, the lateral extensors will pronate the STJ in early swing in order to allow easier toe clearance and then, once the toes have cleared the ground in mid-swing, the anterior tibial will supinate the STJ in order to prepare the STJ to be able to have sufficient pronation motion during contact phase to allow some shock absorption. If the EDL is weak, then this would explain the lack of pronation in early swing that this patient seems to demonstrate.
  14. Up with the lark Prof. Kirby? Agreed it's the neuro-findings that have been confusing me. Perhaps this is a red-herring. I've just spoken with the patient again and there is a history of previous inversion sprain to the ankle- perhaps EDL tendon got damaged in the process. There have been two lots of NCV/ EMG performed first approximately 12-18 months ago and more recently 2 months ago- False negative twice?

    Ian, you asked AFO or Richie Brace? A Richie Brace is an AFO. What benefits do you think the Richie Brace might have over another form of AFO in this case?

    Anyone, got any other ideas in terms of treatment?

    On behalf of myself and the patient, thanks for your time and input in this.
    Last edited: Oct 2, 2008
  15. Griff

    Griff Moderator


    Apologies for not being more clear - I was referring to the particular type of Richie Brace which passively dorsiflexes the foot during the swing phase, as opposed to what I visualise when I hear AFO (the classic rigid L shaped device)

  16. Yeah, no worries- need to look into costings.
  17. efuller

    efuller MVP

    Hi all,

    There is no callus on the toe from spinning at toe off. So, the twist is behavioral at the initiation of swing. In looking at the whole body from behind, part of the funny motion appears to be a "hip hike" where there is sort of a jump to help the left leg clear the ground in swing. Look at the height of the left shoulder in relation to the mark on the far wall with different feet on the ground. There is also less knee flexion on the left during swing. This makes the leg functionally longer and harder to clear during swing. I agree with whoever said that the twist is to help the left foot clear the floor in swing.

    I'll bet she likes the ankle dorsiflexion assist AFO. I have no idea why her knee is not flexing and her foot is not dorsiflexing very much at the initiation of swing and there is much less push off with he right foot. Maybe it's a fatigue issue. If you have any leg weights you could hang off of the foot and see if she fatigues sooner with the left.

    Interesting case,
  18. Further thoughts on this, she does have an incredible range of inversion at the STJ, could the oblique propulsion be supinating the stj so much that the axis is lateral to the EDL insertions, i.e. EDL becomes supinator?

  19. Little chance of the EDL becoming a supinator, in my opinion. However, since the EDL is the prime pronator of the STJ in early swing and if the EDL is weak (for whatever reason), then the anterior tibial (AT), which is a strong supinator, will be need to be used more just to allow sufficient ankle joint dorsiflexion moment in order to help clear the toes over the ground in early swing. And this is what appears to be happening...the AT is winning out over the EDL, causing early swing phase supination which then makes the foot-lower extremity relatively longer for toe clearance during early swing. This "longer foot" during swing will then necessitate the individual to raise the left hip more and flex the hip more during swing in order to allow toe clearance.
  20. Sammo

    Sammo Active Member

  21. Thanks Sam. Patient had MRI of leg and foot today- looking for EDL tendon damage (and anything else in this region). We will probably go for a dynamic assist type AFO (thanks Ian and Eric), but just waiting to see what, if anything, this throws up. I suspect, as Kevin previously suggested that given the normal NCV/ EMG there may be damage/ adhesions to the tendon unit of the EDL preventing normal function.

    I'll post the results when I know them.
  22. Ben

    Ben Member


    Looking at the video's I think there must be something functionally inactive at the hip flexors. Maybe the problem is initiating higher in the spinal cord and impacting psoas major. There definitely appeared to be some trendelenburg signs and the right pelvic position seemed dropped.

    It doesnt look like there was any tib ant/ehl function in dorsiflexing the foot, and maybe can look at quad - specifically rec fem/sartorius - function also??

  23. David Smith

    David Smith Well-Known Member


    I've just looked in on this thread and I've downloaded the vid from admins link but I cant play it on any software I have. I wanted to look in slo mo and magnified.
    Can you send me a vid by email - foothouse@talktalkbusiness.net

    From what I see from your You tube vid and bearing in mind all your test have shown nothing remarkable, the left hip is clearly higher than the right. I would add a 25mm heel lift r/f and taper to 5mm at met heads. Revideo then and then review in 1 week see if anything has changed. It may be that she cannot clear the ground during swing of left leg and just chooses this unusual compensation.


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