– By Meagan Stachnik –
The Chiropractic community is considered a group of professionals educated in the musculoskeletal system, neurology, vitalism, and scientific evidence approaches. Diversity in Chiropractic technique, analysis and philosophy that exists within the profession offers opportunity for clientele to choose the correct approach for their bodies and take control of their care and treatment plan. Patients may not necessarily know the differences and similarities of the assessment techniques performed by chiropractors, but they are always familiar with certain things every chiropractor may perform in one way or another. They’ll say, “My chiro pops my hip”, “My chiro does this hip pull on me”, and “my chiro does this leg sweep”. The terminology is often difficult to interpret when a patient is requesting an adjustment after seeing a different chiropractor, however, one analysis most chiropractors are taught one form of analysis leg length inequality check (LLI). Known by many names such as Derefields or prone leg check, the LLI is one of the most noninvasive tests that can provide a considerable amount of valid functional and structural information regarding a patient. However, should chiropractors trust the reproducibility and validity the LLI? Nguyen and colleagues (1999) sought to answer this question, and herein is a summary of their results and interpretation to shed some light on the LLI technique.
Nguyen et al. examined LLI with an activator method approach with a subject base of 34 patients. Patient exclusion criteria included structural short leg, significant leg trauma, cancer or infection diagnosis, paralysis, prosthesis, fractures or current sprains, and replacement surgery to the knee or hip. Examiners had 15 years of clinical and instructor experience of the activator method. The examiners were unblinded throughout the process. Appropriate footwear coined ‘laced-up oxford shoes’ were key to their protocol to ensure adequate reliability for the test. Inadequate shoes were removed, and the examiner prompted the patient onto a Hi-Lo table. The testing examiners each took turns administering the LLI.
Protocol performed by examiners:
1. Reference point of the leg length – welt of the heels
of the shoes.
2. Palms of their hands cupped the lateral malleoli
and brought legs together until heels touched and
formed horizontal right angles.
3. Thumbs under heel of each shoe, index fingers
on posterior aspect of lateral malleolus indicated a
‘finger gun’ position.
4. Examiners used their thumbs for removal of
inversion or eversion and dorsiflexed feet.
5. Flared or externally rotation of the feet so toes
abducted to a natural angle of 10-20 degrees.
6. Headward pressure applied with thumbs.
7. Leg length then observed and documented
Agreement between examiners was statistically significant (P<0.05) and reported at 85%. Further analysis using Kappa coefficient, which excludes the agreement you might expect by chance, demonstrated a k>0.75 which is considered excellent reproducibility. Unfortunately, the research results collected had a small sample size with a higher evaluation result of right LLI (potential bias). Other potential bias considerations include type l and ll examiner error, other health care treatment plans, equipment or patient position differentiations, and lack of radiographic findings. Leg length limitations could also be indicative of scoliosis to impede the structural or functional integrity of the findings.
Further studies will need to research other methodological evidence to support the findings while taking the elements listed above. Proper leg measurements due to potential fluctuations that can vary between leg lengths of patients and different LLI methods (e.g. drop table) should be considered. Activator method indicates bias between the examiner’s dominant hand to be able to apply more force headward compared to their non-dominant hand which could orchestrate a skewed result. This could be indicative of more right LLI compared to left as both examiners were right hand dominant. Variation in gait among patients could depleteshoe was re patterns and provide inconsistencies in LLI. Shoe wear patterns may depend on whether a patient wears orthotics. Are the orthotics structural and functionally accurate for the patient? Does the patient follow appropriate upkeep and check-in to ensure the orthotics are correctly fitted?
Nguyen et al. established a reproducible study, however, failed to prove clinical significance or validity of LLI. Chiropractors require more justification of their analysis technique to not only defend chiropractic but to expand more research into analysis systems and approaches. The rationale behind the “why” and “success” of certain chiropractic techniques will be able to go further with other health care professionals, patients and ultimately, other chiropractors when we can provide sufficient evidence of clinical and statistical significance of analysis. Reasonable evidence can give grounds for chiropractors to flourish under their respected and chosen technique.