The relationship between pelvic torsion and anatomical leg length inequality: a review of the literature

Abstract

Objective: Although it is common to find assertions relating functional leg length inequality (LLI) to pelvic torsion and other states of subluxation, comments and/or data concerning anatomical LLI in this same context are uncommon. This review of the literature synthesizes the evidence on pelvic torsion in relation to anatomical LLI. Methods: The literature was searched using the PubMed; Manual, Alternative, and Natural Therapy Index System; Allied and Complementary Medicine Database; Cumulative Index to Nursing and Allied Health Literature; and Index to Chiropractic Literature databases for primary studies that related LLI, either artificially created or naturally occurring, to pelvic torsion. Extracted data included natural vs artificial LLI, method of creating or detecting LLI, subject selection, methodology for measuring pelvic torsion, and results. Results: Nine English-language studies were retrieved published 1936-2004. Seven determined the impact of artificial, transient LLI on pelvic torsion, whereas 2 studied the effect of naturally occurring LLI. Conclusion: Across varying methodologies for measuring LLI and pelvic torsion, a consistent, dose-related pattern was identified in which the innominate rotates anteriorly on the side of a shorter leg and posteriorly on the side of the longer leg. This finding was contrary to the common assertion that the ilium rotates posteriorly on the side of a short leg and vice versa. Practitioners of manual medicine who derive vectors for intervention based on leg checking procedures should consider the possibility that the direction of pelvic torsion may be variable depending on whether the LLI is of anatomical or functional origin.

Comparison of Supine and Prone Methods of Leg Length Inequality Assessment

“…Three participants (7.0%) reported prior histories of lower extremity injuries and surgeries. The sample was 37% female, and their mean age was 25.5 years (range: [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42].…”

“…In addition to explaining how a primary posterior ilium rotation may result in a functional short leg, Reviews of the literature have also suggested that an anatomic short leg may be associated with anterior innominate rotation. 29 To link these considerations with the variable impact of prone and supine leg length assessment procedures, we must consider how the patient's body position influences the observation of LLIf. As stated earlier, the authors have suggested that pressure on the PSISs while lying supine mitigates pelvic torsion, thus damping the LLIf commonly attributed to pelvic torsion.…”

“…[19][20][21][22][23][24][25] The clinical interpretation of LLI crucially depends on the distinction between anatomic LLI (LLIa), [26][27][28] wherein the legs are measurably of different length, and functional LLI (LLIf), in which the legs are de facto equal in length and yet 1 has been drawn cephalad in some manner (Table 1). 29,30 A review article on pelvic torsion includes discussion of various models for the functional short leg. 31 Descriptions of leg length assessment procedures do not uniformly take into account that observed LLI (LLIo) may reflect primarily LLIa or LLIf, let alone what diagnostic difference this may make.…”

“…It has been suggested that a functional short leg may be associated with posterior innominate rotation, whereas an anatomical short leg has been found to predict anterior innominate rotation. 29 Considerations such as these suggest that discrimination of functional from anatomic short legs may have an impact on clinical outcomes. 32 Practitioners who focus on the upper cervical spine are also entrenched in functional leg checking.…”

Heuristic exploration of how leg checking procedures may lead to inappropriate sacroiliac clinical interventions

“…Although the article of Cooperstein and Lew primarily intended to review the basic science data on how pelvic torsion is associated with LLI, they did suggest the need to derive the clinical implications of these basic science data: "Given that many clinicians and technique systems believe that posterior innominate rotation occurs on the short leg side, the possibility exists that sacroiliac adjusting procedures may be using inappropriate vectors with a negative impact on patient outcomes". 1 This current article intends to explore the clinical implications of the basic science data.…”