Archive for category Leg Length Inequality/Analysis



With the development of increasing evidence for the use of manipulation in the management of musculoskeletal conditions, there is growing interest in identifying the appropriate indications for care. Recently, attempts have been made to develop clinical prediction rules, however the validity of these clinical prediction rules remains unclear and their impact on care delivery has yet to be established. The current study was designed to evaluate the literature on the validity and reliability of the more common methods used by doctors of chiropractic to inform the choice of the site at which to apply spinal manipulation.


Structured searches were conducted in Medline, PubMed, CINAHL and ICL, supported by hand searches of archives, to identify studies of the diagnostic reliability and validity of common methods used to identify the site of treatment application. To be included, studies were to present original data from studies of human subjects and be designed to address the region or location of care delivery. Only English language manuscripts from peer-reviewed journals were included. The quality of evidence was ranked using QUADAS for validity and QAREL for reliability, as appropriate. Data were extracted and synthesized, and were evaluated in terms of strength of evidence and the degree to which the evidence was favourable for clinical use of the method under investigation.


A total of 2594 titles were screened from which 201 articles met all inclusion criteria. The spectrum of manuscript quality was quite broad, as was the degree to which the evidence favoured clinical application of the diagnostic methods reviewed. The most convincing favourable evidence was for methods which confirmed or provoked pain at a specific spinal segmental level or region. There was also high quality evidence supporting the use, with limitations, of static and motion palpation, and measures of leg length inequality. Evidence of mixed quality supported the use, with limitations, of postural evaluation. The evidence was unclear on the applicability of measures of stiffness and the use of spinal x-rays. The evidence was of mixed quality, but unfavourable for the use of manual muscle testing, skin conductance, surface electromyography and skin temperature measurement.


A considerable range of methods is in use for determining where in the spine to administer spinal manipulation. The currently published evidence falls across a spectrum ranging from strongly favourable to strongly unfavourable in regard to using these methods. In general, the stronger and more favourable evidence is for those procedures which take a direct measure of the presumptive site of care- methods involving pain provocation upon palpation or localized tissue examination. Procedures which involve some indirect assessment for identifying the manipulable lesion of the spine-such as skin conductance or thermography-tend not to be supported by the available evidence.

Chiropr Man Therap. 2013 Oct 21;21(1):36. [PMID:24499598]

Author information: Triano JJ, Budgell B, Bagnulo A, Roffey B, Bergmann T, Cooperstein R, Gleberzon B, Good C, Perron J, Tepe R. Canadian Memorial Chiropractic College, 6100 Leslie St,, Toronto, Ontario, Canada.

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The purpose of this study was to quantify  interexaminer reliability of a standardized supine leg check procedure  used to screen for leg-length inequality.


Two doctors of chiropractic used a standardized  supine leg check procedure to examine 50 volunteers for leg-length  inequality. The order of examination was randomized. The side and  magnitude of leg-length inequality were determined to the nearest 1/8  in. Subjects and examiners were blinded. Interexaminer reliability was  assessed with a Bland-Altman plot, tolerance table of absolute  differences, a quadratic weighted κ statistic for quantitative scores,  and a Gwet’s first-order agreement coefficient for dichotomous ratings.


The quadratic weighted κ statistic to quantify the  reliability of the rating scale was 0.44 (95% confidence interval,  0.21-0.67), indicating moderate reliability. The 2 examiners agreed  exactly 32% of the time, within 1/8 in 58% of the time, within 3/16 in  72% of the time, and within 3/8 in 92% of the time. The Bland-Altman  plot revealed possible heterogeneity in reliability that requires  additional study. The examiners agreed on the presence of a leg-length  inequality of at least 1/8 in in 40 (80%) of 50 subjects (first-order  agreement coefficient, 0.76), suggesting good agreement for this  diagnostic category.


The examiners showed moderate reliability in  assessing leg-length inequality at 1/8-in increments and good  reliability in determining the presence of a leg-length inequality.

J Manipulative Physiol Ther. 2011 May;34(4):239-46. [PMID:21621725]

Author information: Woodfield HC, Gerstman BB, Olaisen RH, Johnson DF. Upper Cervical Research Foundation, Raleigh, NC, USA.

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D. Wayne Rhodes

Private Practice of Chiropractic, Tuscaloosa, AL 35401

Phillip A. Bishop

Department of Kinesiology, University of Alabama

To the Editor:

The Cooperstein and Lew1 article, “The relationship between pelvic torsion and anatomical leg length inequality: a review of the literature,” referenced our work.2 We feel that their statements should distinguish between anatomical leg length inequality (LLI) and functional LLI.

In the discussion section, they indicated that there was “… poor agreement found by Rhodes et al. between visual methods of leg checking and upright radiographs.” We reported the relationship between prone LLI measurements and standing radiograph as “The … correlation coefficient (r) between the two variables was … 0.719.”2 Most statisticians characterize this as a moderate positive correlation and not “poor agreement.”

Anatomical LLI exists. The LLI incidence is not known perhaps because of confused definitions. Mannello3stated, “It appears that the least controversial issue associated with LLI is its anatomical existence.” As we previously stated,2 “Structural, anatomical or actual LLI are synonymous terms and are diagnosed when either the femur or tibia is longer in one leg than in the other, as shown on X-ray.” Mannello3 defined it similarly.

Anatomical LLI denotes different bones lengths of right and left lower extremities. The criterion standard for anatomical LLI is the scanogram, radiograph of both femurs and tibias; so comparisons can be made. Of the scanogram, Mannello3 said, “This procedure is considered a valid indicator of lower extremity length.”

The Cooperstein and Lew review on anatomical LLI did not include any studies involving actual bony differences in leg length. However, Mannello3 pointed out, “Others define anatomical short leg as that which is shorter in length from the floor to the weight bearing surface of the femoral head.” This seems to be the definition adopted by Cooperstein and Lew, but no definition of anatomical LLI was included in their review.

Of the 9 studies in their review, 7 involved simulated LLI, with no anatomical bone length differences seen on radiograph. Of the other 2 included, one used tape measures of legs, which have been shown to be unreliable; as Cooperstein and Lew1 pointed out in their article, “Tape measure methods for measuring LLI have been found to be of equivocal accuracy and may be less accurate than radiological criterion standard method for assessing anatomical LLI.…” The other study included used radiographs of the femur heads, without full views of both lower extremities (Friberg4 method). A developer of that radiograph technique stated, “The method described here is not meant to substitute the methods for measuring accurately the length of the different parts of the lower extremity.”4 One cannot distinguish anatomical (structural) LLI from functional LLI with the Friberg method of comparison.

Methods that incorporate both anatomical and functional LLI without distinction (eg, Friberg method) necessarily overestimate the incidence of anatomical LLI5 compared with a stricter definition.


1. Cooperstein R., Lew M. The relationship between pelvic torsion and anatomical leg length inequality: a review of the literature. J Chiropr Med. 2009;8(3):107–118. [PMC free article] [PubMed]
2. Rhodes D.W., Mansfield E.R., Bishop P.A., Smith J.F. The validity of the prone leg check as an estimate of standing leg length inequality measured by X-ray. J Manipulative Physiol Ther. 1995;18(6):343–346.[PubMed]
3. Mannello D.M. Leg length inequality. J Manipulative Physiol Ther. 1992;15(9):576–590. [PubMed]
4. Friberg O., Koivisto E., Wegelius C. A radiographic method for measurement of leg length inequality.Diagn Imag Clin Med. 1985;54:78–81. [PubMed]
5. Knutson G.A. Anatomic and functional leg-length inequality: a review and recommendation for clinical decision-making. Part I, anatomic leg-length inequality: prevalence, magnitude, effects and clinical significance. Chiropr Osteopat. 2005;13(1):11. [PMC free article] [PubMed]

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The purpose of this study was to evaluate the interexaminer reliability of a leg length analysis protocol between an experienced chiropractor and an inexperienced chiropractic student who has undergone an intensive training program.


Fifty participants, aged from 18 to 55 years, were recruited from the New Zealand College of Chiropractic teaching clinic. An experienced chiropractor and a final-year chiropractic student were the examiners. Participants were examined for leg length inequality in the prone straight leg and flexed knee positions by each of the examiners. The examiners were asked to record which leg appeared shorter in each position. Examiners were blinded to each other’s findings. kappa statistics and percent agreement between examiners were used to assess interexaminer reliability.


kappa analysis revealed substantial interexaminer reliability in both leg positions and also substantial agreement when straight and flexed knee results were combined for each participant. kappa scores ranged from 0.61, with 72% agreement, for the combined positions to 0.70, with 87% agreement, for the extended knee position. All of the kappa statistics analyzed surpassed the minimal acceptable standard of 0.40 for a reliability trial such as this.


This study revealed good interexaminer reliability of all aspects of the leg length analysis protocol used in this study.

J Manipulative Physiol Ther. 2009 Mar-Apr;32(3):216-22. [PMID:19362232]

Author information: Holt KR, Russell DG, Hoffmann NJ, Bruce BI, Bushell PM, Taylor HH. esearch Department, New Zealand College of Chiropractic, Auckland, New Zealand.

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The purpose of this study was to perform an interexaminer reliability evaluation of the prone leg length analysis procedure.


Two chiropractors each examined a series of 45 patients with a history of low back pain. Patients were in the prone position, with the knees in both extended and flexed positions, and with the head rotated right and left. The clinicians were asked to determine the side of the short leg with knees extended and if a change in leg length occurred with head rotation or when the knees were flexed. They were also asked to visually judge the amount of leg length differential by categorizing the difference as either less than 0.25, 0.25 to 0.5, 0.5 to 0.75, or more than 0.75 in. The head rotation portion of the test was performed only with patients (n = 22) in whom the leg length differential was determined to be less than 0.25 in.


kappa statistics and frequency distributions were calculated for each of the respective observations. Reliability of determining the side of the short leg with knees extended was good at 82% agreement (kappa = 0.65) but fair for determining the amount of leg length difference at 67% agreement (kappa = 0.28). Reliability of the head rotation testing procedure was extremely poor, with only 50% and 45% agreement about the observed change in leg length with the head rotated left and right, respectively (kappa = 0.04, kappa = -0.195). There was no significant correlation found between the side of reported pain by the patient and the side of the short leg as noted by either clinician (chi2 = 0.55, P = .91, and chi2 = 1.55, P = .67). All of the patients (100%) were judged to have a leg length difference by both clinicians. When the knees were flexed, there was 93% agreement that the short leg became longer (43/45 cases), with no reported cases of the short leg getting shorter. Calculation of kappa statistics was confounded for these last 2 observations because of extremely high prevalence bias.


The results indicate that 2 clinicians show good reliability in determining the side of the short leg in the prone position with knees extended but show poor reliability when determining the precise amount of that leg length difference. The head rotation test for assessing changes in leg length was unreliable in this sample of patients. There does not appear to be any correlation between the side of pain noted by the patient and the side of the short leg as observed by the clinicians; all 45 patients in this sample were found to have a short leg by both clinicians.

J Manipulative Physiol Ther. 2007 Sep;30(7):514-21. [PMID:17870420]

Author information: Schneider M, Homonai R, Moreland B, Delitto A. Spine and Pain Care Center, Pittsburgh, Pa, USA.

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Activator Methods Chiropractic Technique (AMCT) has based its methods on a systematic protocol developed to determine the functional short leg or the “pelvic deficient side” Relative changes in leg length must be observed accurately by the examiner in order to be certain that the diagnosis and correction of subluxation were effective. Research has been conducted in the past to evaluate interexaminer reliability of prone leg-length assessment, with findings that reliability can be fair to good. Motion palpation and misalignment palpation have been determined to have poor to moderate reproducibility. However, these remain the gold standard of analysis at chiropractic colleges. The objective of this study was to determine if the AMCT procedures for determining leg-length discrepancy could be taught effectively by observing for reproducibility between examiners in a student population.


In a chiropractic college technique classroom setting, prior to training in AMCT procedures, 80 student patients were instructed to lie in the prone extended position. Each was instructed to wear shoes with welts or surgical boots and to remain motionless throughout all evaluative procedures. A chiropractor rated at advanced proficiency in AMCT used leg-length analysis to evaluate each student patient for leg- length discrepancy. The procedure includes observation of the shoe welt in the prone extended position; cupping the lateral malleoli with the examiner’s palms; and a “6-point landing” which involves positioning the index and middle fingers of the examiner around the lateral malleoli and the thumbs on the patient’s heels. Each student patient was assessed to have a right short leg, a left short leg, or even leg lengths. The results were recorded by the examiner and concealed. Immediately following, 80 untrained student doctors evaluated each of the student patients based on their prior knowledge of leg-length analysis. Results for each were recorded on a ballot and concealed from the next student doctor in an envelope as they rotated to the next student patient until all 80 were evaluated. The envelopes and ballots were collected and the student doctors’ results were compared to the AMCT doctor. Approaching the end of the Basic AMCT course, the procedure above was repeated by both the AMCT doctor and the trained student doctors. The data were analyzed and interexaminer reliability was calculated based on the student doctors’ results compared to the AMCT doctor’s results pre- and post- training


Pre-training analysis revealed an average of 69.9% between the students and the AMCT examiner in the 80 subjects, whereas post-training analysis revealed an average of 82.2% agreement. Overall improvement was found in 67% of the cases upon post-training analysis. Results were consistent in both pre- and post-training analysis in 14% of the cases and agreement declined in 19% of cases. Forty-three percent of students were in 100% agreement with the AMCT examiner after course training, compared to only 14% prior to course training. Sixty-six percent were at or above 80% agreement post-training, compared to 45% pre-training; 78% were at or above 70% agreement post-training, compared to 57% pre training; and only 10% were below 50% agreement after being trained in AMCT leg-length analysis, compared to 24% prior to being trained in AMCT leg checks.


The data collected indicate that leg-length analysis utilizing the AMCT protocol can be effectively taught in order to generate reproducible results. When a standard procedure is utilized, the results of interexaminer reliability remain most consistent. Therefore if leg-length analysis is going to be used in practice, it should be recommended that AMCT leg checks be taught in chiropractic colleges to improve reliability in the field. Although leg-length evaluation is used only for functional deficiencies, there was no exclusion of student patients who have a structural short leg, as every student is a class participant. This inclusion may have skewed results. Students or doctors in training of leg-length analysis must be made aware of the need to evaluate for a structural short leg using Allis’ test, tape measure, or X-ray analysis of femur head heights during their initial examination. They should also know that patient history of childhood epiphyseal disease or fracture could indicate an existing structural problem. The reproducibility of AMCT is dependent on some variables, and in this particular study footwear was controlled. However, inappropriate tables and patient positioning could have resulted in lower reliability. It is standard with AMCT to utilize a hi-lo elevation table to eliminate active positioning; therefore, weight bearing distortions and postural asymmetries are preserved. This study does not address the validity or clinical significance of prone leg checks. Many field practitioners value leg-length assessment to determine pelvic obliquity, assuming abnormal loading results and affects spinal alignment.


Pre-training analysis revealed an average of 69.6% agreement between the students and the AMCT examiner in the 80 subjects, whereas post-training analysis revealed an average of 82.2% agreement. Overall improvement was found in 67% of the cases upon post-training analysis. Results were consistent in both pre- and post-training analysis in 14% of cases and The AMCT leg check protocol appears to offer promise in consistency and interexaminer reliability. The results of this classroom study are encouraging and suggest that with further controlled studies, uniformity in leg-length analysis could be reached within the chiropractic profession.

Author information: Janeen Wallace, DC, New York Chiropractic College

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To investigate the interexaminer reliability of the prone extended relative leg-length check as described by Activator Methods, Inc.


Thirty-four subjects were selected from a pool of 52 consecutive patients visiting a private chiropractic office.


Exclusion criteria included congenital or acquired conditions known to affect lower extremity length and inability to lie prone for a 10-minute period. Two experienced chiropractors who specialize in Activator Methods and are “advanced-proficiency rated” by Activator Methods, Inc. assessed each patient in random order for leg length inequality. Findings were recorded as left short leg, equal leg length, or right short leg.


The data for 34 subjects were organized in a 3 x 3 contingency table. Total agreement was 85%. A simple, unweighted kappa value yielded kappa = 0.66. A disproportionately greater number of right short leg findings than left short leg findings were observed by both examiners. In only 2 instances were equal leg lengths observed, and both were detected by the same examiner. Because examiners found only 2 of 34 subjects with equal leg lengths, several secondary analyses involving data reductions were conducted. The resulting kappa values were similar to the 3 x 3 analysis.


There was good reproducibility between 2 examiners by using the Activator Method to detect leg length inequality in the prone extended position. This study does not address the validity or clinical significance of the measurement method. Future studies should include larger numbers, a wider variety of subjects, and a diversity of examiners.

J Manipulative Physiol Ther. 1999 Nov-Dec;22(9):565-9. [PMID:10626698]

Author information: Nguyen HT, Resnick DN, Caldwell SG, Elston EW Jr, Bishop BB, Steinhouser JB, Gimmillaro TJ, Keating JC Jr. Los Angeles College of Chiropractic, Whittier, Calif, USA.

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To abstract the essential elements of chiropractic prone leg checking and subject them to controlled, experimental parametric testing.


Controlled, objective, repeated-measure analysis of the dynamic response of leg positions to distractive and compressive loading conditions.


Research laboratory in a chiropractic college.


Twenty-five compression and 30 distraction subjects, most of whom were male, asymptomatic chiropractic students.


The subjects were lowered to the prone position on a table optimized to detect dynamic leg positions, with separate sliding segments supporting each leg. A trial consisted of a 2-min control run, followed by two 2-min experimental runs in which compressive or distractive loads were applied incrementally to the table-leg segments.


An optoelectric system measured real-time absolute and relative leg positions.


Right legs showed a greater average response than left legs under both distractive and compressive loads, and tended to respond more proportionately to incremental load increases. The average response to compression exceeded the response to distraction. Both legs showed a greater average response in the second half of the trials. Correlation of weights with responses was about four times greater in traction than compression.


The functional short leg is confirmed as a stable clinical reality, a multitrial mean of unloaded leg positional differences. The prone leg check may be a loading procedure, albeit unmeasured, that detects non-weight-bearing, functional asymmetry in loading responses. These probably reflect differences in left-right muscle tone, joint flexibility and tissue stiffness. The relatively nonmonotonic, nonlinear quality of left leg responses is consistent with asymmetric neurological responses.

J Manipulative Physiol Ther. 1998 Jan;21(1):19-26. [PMID:9467097]

Author information: Jansen RD, Cooperstein R. Palmer Center for Chiropractic Research, Palmer College of Chiropractic West, San Jose, CA 95134, USA.

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The chiropractic concept of vertebral subluxation has served the purpose of unifying early DC’s by contrasting a unique approach to health problems offered by chiropractors to allopathic medicine. However, confusion over the use of this term, and the concepts surrounding it, has existed because of a lack of consensus among chiropractors. A variety of methods has been offered to identify and measure the effects of vertebral subluxation in order to provide evidence regarding its existence. How the chiropractic profession deals with its belief systems and model building in this era of increasing accountability may be more important than the search for the subluxation itself.


In order to assist practitioners to cope with this dilemma, an overview of selected subluxation assessment procedures is provided including a qualitative review of relevant studies examining reliability and validity of the various approaches. Criteria for assessing technology are presented, and recommendations are made regarding the value of a number of currently available assessment strategies. A discussion of future technology assessment issues is offered.

Top Clin Chiropr 1996; 3: 1-9.

Author information: Osterbauer, PJ.

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