Slight pelvic obliquity is normal in a healthy population: a cross‐sectional study

Abstract

Purpose Pelvic obliquity (PO) has not been extensively investigated, and there is no gold standard for measurement. The PO is essential for surgeons in planning hip arthroplasty, which includes the restoration of leg length discrepancy (LLD). We aimed to establish a normative range of PO angles by measuring healthy individuals without musculoskeletal disorders. Methods Our study included 134 consecutive cases (70 females) referred to our institution between April 2020 and September 2021 for non-orthopedic problems. Patients were screened for normal gait and posture using the visual observation method (VOM) and the Modified Gait Abnormality Rating Scale (GARS-M). In standing standard radiographs, the PO angle was measured as the angle between the horizontal plane and the inter-teardrop line. Results Patients' mean age and Body Mass Index (BMI) were 39.7 ± 16.8 and 22.3 ± 3.1, respectively. PO angles did not follow a normal distribution, with a median (IQR) of 2.0° (0.9°—3.1°). According to the Wilcoxon one-sample test, the median PO angle differed significantly from zero (P < 0.001). The PO angle did not differ significantly between males and females (2° vs. 2°, P = 0.46), nor did it correlate significantly with age (P = 0.24). Considering the 95% percentile of PO angles was 5.6°, this range (0°—5.6°) was regarded as a normative value. Conclusion Normative values for PO in the normal healthy population range from 0° to 5.6°, with a median value of 2.0°. The PO angle was independent of age and sex and differed significantly from 0°. Slight pelvic obliquity may be normal, and physicians should not always assume that it is caused by pain, scoliosis, or weakness of the abductors. Level of evidence III.

Effects of Artificially Induced Leg Length Discrepancy on Treadmill-Based Walking and Running Symmetry in Healthy College Students: A Lab-Based Experimental Study

“…The size of the study sample was considered adequate to achieve statistical significance with a = 0.05, with an 80% power and effect size (f) = 0.25 (calculated based on a partial η 2 = 0.06), based on an a priori power analysis using an online power analysis application (G*Power v. 3.1.9.2; Universität Düsseldorf: Psychologie – HHU, Düsseldorf, Germany). Individuals with musculoskeletal soft tissue or joint injuries of the lower limb, pathological conditions that could prevent normal walking and running, or a leg length discrepancy of >5 mm, as well as excessive skeletal deviations in the trunk (e.g., >5.0° of rotation of the thoracic or lumbar spine when performing the Adam’s test indicative of ≥20° scoliosis), pelvis (e.g., >2° obliquity [ 41 ]), and feet (e.g., overpronation or supination as defined by the Foot Posture Index-6, (FPI-6 [ 42 ])), were excluded from the study. All inclusion/exclusion criteria that were related to prior lower extremity injuries and frontal plane body deviations were selected based on the clinical applicability and the potential impact that they could have on the study variables.…”

Exploring 3D Pelvis Orientation: A Cross-Sectional Study in Athletes Engaged in Activities with and without Impact Loading and Non-Athletes

“…Herrington showed that the pelvis was tilted anteriorly by no more than 7° in most of the asymptomatic population studied [ 9 ]. In a recent study, Moharrami et al identified pelvic obliquity ranging from 0° to 5.6° in male and female individuals considered part of the normal population [ 10 ]. In essence, the outcomes of these studies suggest that the pelvis in the general population undergoes positional shifts influenced by both internal forces from capsuloligamentous structures and muscles, as well as external impacts arising from daily activities such as interactions with the ground.…”