I have been avidly reading your postings and I have two things!:
1 Love, love, LOVE your blog! Thankyou for all your pearls - I have learnt lots and lots as a Podiatrist both technically and also in the lesson of never giving up on patients and their problems.
2 You put great emphasis on LLD assessment and treatment. Im always looking for info on this subject. You have put up quite a lot of stuff on this (including the diamond on full-length lifts - thanks!) but Im still slightly confused. In a nut shell can you lay out your structured approach to a new patient when trying to identify if they have a functional or actual LLD. If you have the time...please treat me as a novice!
thank you again
Dear Lawrence, Thank you very much for your kind words. I hope I can explain my thoughts well when I know it will affect many of your patients. I will work off the following outline of my overall approach, the timing can vary from patient to patient.
- History is taken for present and past injuries looking for patterns
- Gait evaluation looks for asymmetries with limb dominance pointing toward some type of limb length discrepancy
- Whether or not the patient has orthotic devices to correct for asymmetrical pronation, the standing exam done looks for differences at iliac crests, greater trochanters, and anterior superior iliac spines.
- Measure with and without orthotic devices the resting calcaneal stance postition (sum total of all pronatory and supinatory forces) for both sides with 3 degree difference significant for functional limb length difference
- Blocks (lifts) are placed under the supposed short leg and the 3 landmarks are measured (differences can be seen, even as to what side is short)
- Gait evaluation is done with lifts under the short side to see if there is complete resolution of limb dominance (of course, only 3/8 to 1/2 inches can be tested with athletic shoes)
- Gait evaluation will either show complete resolution, partial resolution, or worsening of the limb dominance
- When performing the gait evaluation without lifts initially (with and without orthotic devices if they have) note asymmetry of pronation (if you see asymmetry it is normally 5 degrees or more)
- When a patient has asymmetrical pronation, the shoes may break down uneven, making some of this exam very cursory until they purchase a new stable shoe
- If the pronation is asymmetrical and moderate to severe, the examiner may want to work on their pronation first, or second (since lift therapy can be much easier to get started)
When taking a history, limb length diffences have been tied to unilateral complaints (ie achilles tendonitis or plantar fasciitis on one side only), or continual one sided complaints over time (ie right knee pain 1999, right plantar fasciitis 2002, right hip pain 2007, and right achilles pain 2010). It is important to look at these patterns to see if treatment is worth the effort at times. Sometimes, I just point out that this is a potential area to delve into especially if the patient presents with a relatively minor problem (ie 2010 2 week history of right achilles pain). Remember the KISS principle.
Gait evaluation is my benchmark for analysis. When you see limb dominance (tendency to shift weight primarily to one side), you could be looking at several possibilities. Limb dominance is fairly easy to observe by watching the head. Does the head spend more time on one side of the body over the another? If so, it is called limb dominance. You could be dealing with a structural LLD, functional LLD, combination of structural and functional LLD ( limb length discrepancy), or a problem in the pelvis or spine (pelvic asymmetry or scoliosis).
How is this sorted out? Do the standing examination for limb length discrepancy and look at the height differences between the right and left side. The Anterior Superior Iliac Spines and the Iliac Crests are Pelvic Landmarks and the Greater Trochanters are a Femoral Landmark. Measure the difference by placing lifts under the shorter side until you level each landmark. Understand that you normally get different results at each point, so there will be some art in the introduction of lift therapy, unless you opt for Standing AP Pelvic Xrays. For Example, if you measured 6 mm at the Iliac Crest, 3 mm at the Greater Trochanters and 9 mm at the Anterior Superior Iliac Spines, but all showing the right shorter, you probably have a short right leg of 3 mm or greater.
Now, I will also measure the relaxed calcaneal stance position difference between the two sides. If they have orthotic devices, measure with and without so you can get a feel of the change that the orthotics make. Is it the same as you observe in gait evaluation. It is documented that a greater than 3 degreee difference between the sides means that a functional leg length difference exists. But, that is only one aspect, since there can definitely be asymmetrical pronation without a difference in the heel position.
When the standing exam points to a possible structural leg length difference, and your measurements approximate that difference, make the lifts for the short side in 1/8inch increments (ie. 3 lifts if 3/8inch is measured). Try to keep the lifts full length if possible, but they are tapered at the sulcus, and rarely go under the toes. This may require a separate visit to have the lifts made and/or the patient return with athletic shoes. Watch the patient walk and/or run with the lifts you feel will correct out the difference fully (we are limited to around 1/2inch, with part being just in the heel). Does this completely eliminate the limb dominance? Do not worry if the patient feels awkward, since it will take awhile to build up to that total amount. I will normally start with 1/8inch and add another 1/8th every 2 weeks. Start Low and Go Slow is the lift mantra.
This is a crucial time for the functional component. If you watched the gait pattern and felt that the patient had asymmetrical pronation (even if one side was normal, and the other overly supinates), then that patient has a functional or combination leg length difference. When you use lifts, or orthotics which lift the patient up in their shoes, watch the change in that pattern. By correcting with lifts, does the asymmetry improve, stay the same, or get worse, and how? Does the side that pronates more now pronate less, the same, or more? Does the side that pronates less now pronate less, the same, or more? These are very important observations especially when the patient looks worse. I have had to settle on a lower than ideal lift height when added lifts make the shoe too unstable and either the pronation worse, or produce lateral instablity (over supination). You must watch the patient with every pair of shoes that they put lifts on or into.
Recently, when I thought I had mastered this topic (ha ha!!!), I had 3 patients in a row, that after measuring their limb length difference and deciding on their lifts, looked worse in their limb dominance with those lifts. All 3 of these patients then had AP Standing Pelvic Xrays with shoes and orthotics on documenting that the other side was short. 80% of the time the standing exam is correct and the limb dominance disappears with lifts placed under the short side. Medicine will always attempt to keep us humble.
So, I hope this has helped, but I know at least for my sake, I better summarize this thoughts. I think a checklist will help.
New Patient Limb Length Discrepancy Checklist
- Historical Findings suggestive of LLD:
- Gait Findings Barefoot of Limb Dominance: Right or Left of Greater Pronation One Side: Right or Left
- Gait Findings Barefoot of Asymmetrical Pronation: Right Greater Left Greater (circle one)
- Gait Findings of Limb Dominance if orthotics made:
- Gait Findings of Asymmetrical Pronation if orthotics made:
- Block Test Results (side patient felt needed lift):
- Does patient need to bring in stable shoes for Gait Exam with lifts?
- Relaxed Heel Position with Orthotics: Right Left
- Relaxed Heel Position without Orthotics: Right Left
- Does the patient have good functioning orthotic devices?
- Did the orthotics make a difference in your exam of relaxed heel position?
- Should the orthotics be redone to better control pronation of one or both sides?
- Standing ASIS (ant sup iliac spine) higher: Right Left (circle one)
- Standing Iliac Crest higher: Right Left (circle one)
- Standing Greater Trochanter higher: Right Left (circle one)
- Amount to Level Iliac Crests (with orthos if they make difference):
- Amount to Level ASIS (with orthos if they make difference):
- Amount to Level Greater Trochanters (with orthos if they make difference):
- Should we consider xray evaluation?
- Estimated Initial Lift to be tried:
- Amount of Lift needed to Eliminate Limb Dominance:
- Troubles experienced by the patient getting used to the lifts:
- Summary of Possible Structural Short Leg:
- Summary of Functional Component: (circle one) Long Leg Pronate Short Leg Pronate