The role of lumbar lordosis and pelvic sagittal balance in femoroacetabular impingement

Abstract

Aims The purpose of this study was to evaluate spinopelvic mechanics from standing and sitting positions in subjects with and without femoroacetabular impingement (FAI). We hypothesize that FAI patients will experience less flexion at the lumbar spine and more flexion at the hip whilst changing from standing to sitting positions than subjects without FAI. This increase in hip flexion may contribute to symptomatology in FAI. Patients and Methods Male subjects were prospectively enrolled to the study (n = 20). Mean age was 31 years old (22 to 41). All underwent clinical examination, plain radiographs, and dynamic imaging using EOS. Subjects were categorized into three groups: non-FAI (no radiographic or clinical FAI or pain), asymptomatic FAI (radiographic and clinical FAI but no pain), and symptomatic FAI (patients with both pain and radiographic FAI). FAI was defined as internal rotation less than 15° and alpha angle greater than 60°. Subjects underwent standing and sitting radiographs in order to measure spine and femoroacetabular flexion. Results Compared with non-FAI controls, symptomatic patients with FAI had less flexion at the spine (mean 22°, sd 12°, vs mean 35°, sd 8°; p = 0.04) and more at the hip (mean 72°, sd 6°, vs mean 62°, sd 8°; p = 0.047). Subjects with asymptomatic FAI had more spine flexion and similar hip flexion when compared to symptomatic FAI patients. Both FAI groups also sat with more anterior pelvic tilt than control patients. There were no differences in standing alignment among groups. Conclusion Symptomatic patients with FAI require more flexion at the hip to achieve sitting position due to their inability to compensate through the lumbar spine. With limited spine flexion, FAI patients sit with more anterior pelvic tilt, which may lead to impingement between the acetabulum and proximal femur. Differences in spinopelvic mechanics between FAI and non-FAI patients may contribute to the progression of FAI symptoms. Cite this article: Bone Joint J 2018;100-B:1275–9.

Posterior Pelvic Tilt From Supine to Standing in Patients With Symptomatic Developmental Dysplasia of the Hip

“…For sagittal spinal alignment, parameters were measured from a standing lateral radiograph of the whole spine. Specifically, thoracic kyphosis (TK), lumbar lordosis (LL), deviation of the sagittal vertical axis (SVA), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and proximal femoral angle (PFA) were measured . As clinical assessments, the Visual Analogue Scale (VAS) and the Western Ontario, and McMaster universities (WOMAC) OA index were evaluated prior to and 2 years after surgery.…”

“…Specifically, thoracic kyphosis (TK), lumbar lordosis (LL), deviation of the sagittal vertical axis (SVA), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI), and proximal femoral angle (PFA) were measured. [26][27][28] As clinical assessments, the Visual Analogue JOURNAL OF ORTHOPAEDIC RESEARCH ® MARCH 2020 29 were evaluated prior to and 2 years after surgery. Additionally, range of motion (ROM) of the hip was measured by physical therapists preoperatively.…”

“…The sitting position is a functional position for the hip joint. It has been reported that the sitting position for patients following total hip arthroplasty was related to dislocation, and for patients with FAIS, it was related to impingement of the cam region . However, the weight‐bearing position is not the sitting position, but the standing position.…”

“…It has been reported that the sitting position for patients following total hip arthroplasty was related to dislocation, 27 and for patients with FAIS, it was related to impingement of the cam region. 28 However, the weight-bearing position is not the sitting position, but the standing position. In the standing position for patients with DDH, insufficient femoral head coverage by the acetabulum is more important than in the sitting position.…”

Editorial Commentary: The Hip-Spine Connection in Patients Undergoing Hip Arthroscopy: Should We Learn From Total Hip Replacement and Counsel Patients Differently If They Have Had Previous Back Surgery?

“…Individuals with the morphological features of FAI may remain asymptomatic if the spine is sufficiently mobile to provide compensatory flexion to avoid excess flexion at the hip joint. 8 A decreased pelvic incidence has been related to radiographic signs of FAI, as well. [9][10][11][12] These results suggest that limited range of motion in the spine can alter spinopelvic parameters and subsequently change the joint mechanics of the hip.…”