Radiological severity of hip osteoarthritis in patients with adult spinal deformity: the effect on spinopelvic and lower extremity compensatory mechanisms

Association of radiological severity of hip involvement with clinical characteristics and sagittal spinopelvic balance in patients with ankylosing spondylitis

INTRODUCTION

This is the first study to analyze the associations between the radiological severity of hip involvement with clinical characteristics and sagittal spinopelvic balance in patients with ankylosing spondylitis (AS).

METHOD

We evaluated 182 patients with AS who were referred to outpatient clinics. Patient demographic data and clinical and radiographic parameters were collected. Patients were divided into three groups based on the Bath Ankylosing Spondylitis Radiology Hip Index. Clinical characteristics and spinopelvic parameters acquired by a low-dose biplanar imaging system were evaluated among these groups.

RESULTS

Patients with more severe hip involvement were older and had longer disease duration and diagnostic delay, with lower Harris Hip Score (p < 0.001) and 12-item Short Form Health Survey Physical Component Score (p < 0.001) and higher Bath Ankylosing Spondylitis Disease Activity Index (p = 0.030) and Functional Index (p < 0.001). Patients with more severe hip involvement had significantly higher sacroiliac grade (p < 0.001) and higher modified Stoke Ankylosing Spondylitis Spinal Score (p < 0.001). Patients with moderate and severe hip involvement had similar lumbar lordosis and spino-sacral angle, whereas patients with severe hip involvement had lower pelvic tilt, pelvic femoral angle, higher sacral slope, and sagittal vertical axis.

CONCLUSIONS

The severity of hip involvement is associated with physical function and is not consistent with the severity of spinal involvement. Severe hip involvement impairs the ability to retrovert the pelvis to accommodate the sagittal deformity, and spinopelvic parameters should be concretely evaluated in preoperative counseling of patients with AS waiting for total hip arthroplasty. Key Points • The severity of hip involvement in patients with AS is associated with physical function. • Severe hip involvement impairs the ability to retrovert the pelvis to accommodate the sagittal deformity.

Revealing the Effect of Spinopelvic Alignment on Hip Disorders

Background

Hip osteoarthritis (HOA) is a growing burden and one of the leading causes of hip pain. The relationship between the HOA and the alignment of the spinopelvic region has been intensively studied, however the issue remains controversial. Spinopelvic imbalance, HOA, and dysplasia were investigated in relation to sagittal spinopelvic parameters in this study.

Methods

We collected computerized tomography (CT) topograms of the pelvis or abdomen from 380 patients. In antero-posterior (AP) topograms, Tonnis grading, center-edge angle (CEA) and Sharp's acetabular angle (AA) measurements were performed on each patient. Lateral topograms were used to evaluate the following spinopelvic parameters for each patient: pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), sacral table angle (STA), lumbar lordosis (LL), proximal lumbar lordosis (PLL), distal lumbar lordosis (DLL), and PI-LL difference. Initially, the cohort was divided into two subgroups based on whether or not they had HOA. Then, they were divided into two subgroups based on whether or not they had dysplasia. Ultimately, it was divided in half based on the PI-LL imbalance. Statistical analyses were conducted to determine the likely correlations between the spinopelvic parameters of these subgroups. In addition, the correlations between spinopelvic parameters were investigated.

Results

There were 380 patients evaluated. We found no association between HOA or dysplasia and spinopelvic parameters. In addition, there was no association between PI-LL imbalance and HOA or dysplasia.

Conclusion

There was no difference in constant PI and STA angle, besides other variable parameters, between groups having HOA and dysplasia or not. PI-LL imbalance has no effect on HOA and dysplasia.

Bilateral psoas release for long standing hip-spine syndrome: surgical technique and case report

Background

Severe positive sagittal malalignment can potentially lead to shortening and contracture of the psoas and joint capsule in a flexed spinopelvic position. The utilization of bilateral psoas release to supplement sagittal spinal deformity correction in the same hospitalization was not reported in the literature.

Case presentation

A 66-year-old patient presented with a 5-year history of severe global spinal deformity (sagittal vertical axis 220 mm, 60° spinopelvic mismatch) that did not improve on supine radiographs, and a modified Thomas test with more than 30° flexion contracture of bilateral hips. A 3-stage operation utilizing posterior spinal column osteotomies, anterior lumbar interbody fusion, and bilateral psoas releases was performed.

Outcome

Her postoperative alignment significantly improved and she was pleased with her new posture and the ability to stand up straight.

Conclusions

This report is the first to demonstrate safe and substantial correction of severe spinal deformities associated with bilateral hip flexion contracture in 1 hospitalization.

The Impact of Global Spinal Alignment on Standing Spinopelvic Alignment Change After Total Hip Arthroplasty

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

The interactions between hip osteoarthritis (OA) and spinal malalignment are poorly understood. The purpose of this study was to assess the influence of total hip arthroplasty (THA) on standing spinopelvic alignment.

METHODS

In this retrospective cohort study, patients undergoing THA for OA with pre-and postoperative full-body radiographs were included. Standing spinopelvic parameters were measured. Contralateral hip was graded on the Kellgren-Lawrence scale. Pre-and postoperative alignment parameters were compared by paired t-test. The severity of preoperative thoracolumbar deformity was measured using TPA. Linear regression was performed to assess the impact of preoperative TPA and changes in spinal alignment. Patients were separated into low and high TPA (<20 or >/=20 deg) and change in parameters were compared between groups by t-test. Similarly, the influence of K-L grade, age, and PI were also tested.

RESULTS

95 patients were included (mean age 58.6 yrs, BMI 28.7 kg/m2, 48.2% F). Follow-up radiographs were performed at mean 220 days. Overall, the following significant changes were found from pre-to postoperative: SPT (14.2 vs. 16.1, P = 0.021), CL (-8.9 vs. -5.3, P = .001), TS-CL (18.2 vs. 20.5, P = .037) and SVA (42.6 vs. 32.1, P = .004). Preoperative TPA was significantly associated with the change in PI-LL, SVA, and TPA. High TPA patients significantly decreased SVA more than low TPA patients. There was no significant impact of contralateral hip OA, PI, or age on change in alignment parameters.

CONCLUSION

Spinopelvic alignment changes after THA, evident by a reduction in SVA. Preoperative spinal sagittal deformity impacts this change. Level of evidence: III.

ASD with high pelvic retroversion develop changes in their acetabular orientation during walking

Introduction

It was hypothesized that pelvic retroversion in Adult Spinal Deformity (ASD) can be related to an increased hip loading explaining the occurrence of hip-spine syndrome.

Research question

How pelvic retroversion can modify acetabular orientation in ASD during walking?

Methods

89 primary ASD and 37 controls underwent 3D gait analysis and full-body biplanar X-rays. Classic spinopelvic parameters were calculated from 3D skeletal reconstructions in addition to acetabular anteversion, abduction, tilt, and coverage. Then, 3D bones were registered on each gait frame to compute the dynamic value of the radiographic parameters during walking. ASD patients having a high PT were grouped as ASD-highPT, otherwise as ASD-normPT. Control group was divided in: C-aged and C-young, age matched to ASD-hightPT and ASD-normPT respectively.

Results

25/89 patients were classified as ASD-highPT having a radiographic PT of 31° (vs 12° in other groups, p ​< ​0.001). On static radiograph, ASD-highPT showed more severe postural malalignment than the other groups: ODHA ​= ​5°, L1L5 ​= ​17°, SVA ​= ​57.4 ​mm (vs 2°, 48° and 5 ​mm resp. in other groups,all p ​< ​0.001). During gait, ASD-highPT presented a higher dynamic pelvic retroversion of 30° (vs 15° in C-aged), along with a higher acetabular anteversion of 24° (vs 20°), external coverage of 38° (vs 29°) and a lower anterior coverage of 52° (vs 58°,all p ​< ​0.05).

Conclusion

ASD patients with severe pelvic retroversion showed an increased acetabular anteversion, external coverage and lower anterior coverage during gait. These changes in acetabular orientation, computed during walking, were shown to be related to hip osteoarthritis.

Lack of correlation between hip osteoarthritis and anatomical spinopelvic parameters obtained in supine position on MRI

PURPOSE

Hip osteoarthritis (HOA) is known to have a multifactorial pathogenesis. Recent studies suggest that spinopelvic alignment may represent an important additional pathogenic abnormality resulting in HOA. This study aims to assess the correlation between spinopelvic parameters (pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL)) obtained in the supine position on MRI and HOA, lateral center edge (LCE) angle, and patient reported back pain.

METHODS

Asymptomatic participants from the whole-body MRI cohort (FF4) from the cross-sectional case-control "Cooperative Health Research in the Region of Augsburg" study (KORA) were included. Whole-body MRI was performed in a standardized fashion in each case, on which hip osteoarthritis (HOA), anatomical spinopelvic parameters and lateral center edge angle were measured. Presence of back pain was assessed using a standardized questionnaire. Correlations were estimated by logistic regression models providing odds ratio.

RESULTS

Among 340 subjects (mean age 56.3 ± 9.3 years; 56.5% male), HOA was present in 89.1% (male: 87.0%, female: 91.7%, p = 0.17). The LCE angle was 30.0° ± 5.5 (men: 29.8° ± 5.9; women: 30.1° ± 5.1; p = 0.696). Mean PI was 54.0° ± 11.3°, PT was 13.7° ± 5.9°, SS was 40.3° ± 8.8° (significantly smaller in women p<0.05) and LL was 36.4° ± 9.6° (significantly greater in women p<0.05). None of the spinopelvic parameters correlated significantly with hip osteoarthritis or LCE angle. HOA was not correlated with back pain.

CONCLUSION

Spinopelvic parameters as measured in the supine position on MRI, do not correlate with hip osteoarthritis or lateral center edge angle.

Risk Factors for Progressive Spinal Sagittal Imbalance in the Short-Term Course after Total Hip Arthroplasty: A 3 Year Follow-Up Study of Female Patients

Total hip arthroplasty (THA) for patients with hip osteoarthritis improves hip flexion contracture, subsequently improving spinal sagittal balance. However, in some cases, spinal sagittal imbalance develops in the course after THA, and its risk factors remain unknown. We aimed to investigate the risk factors of progressive spinal sagittal imbalance after THA. This retrospective cohort study of a prospectively maintained database included female patients aged ≥50 years who underwent THA. Before performing THA, we obtained each patient’s anthropometric and muscle strength measurements and whole-spine radiographs. Three years postoperatively, patients underwent whole-spine radiography to examine changes in the spinal sagittal balance. Patients were assigned into groups on the basis of their preoperative and 3 year postoperative sagittal vertical axis (SVA) values. Patients with 3 year postoperative SVA values ≥40 mm with an increase ≥30 mm were categorized into the imbalance group; the other patients were categorized into the non-imbalance group. Of 103 patients, 11 (10.7%) were in the imbalance group. In multiple logistic regression analysis, preoperative weak abdominal trunk muscle strength (ATMS) (p = 0.007) and small sacral slope (SS) (p = 0.005) were significant risk factors for progressive spinal sagittal imbalance. In conclusion, risk factors for progressive spinal sagittal imbalance after THA were weak preoperative ATMS and small SS.

Relieved Low Back Pain after Total Hip Arthroplasty in Patients with Both Hip Osteoarthritis and Lumbar Degenerative Disease

Objective

To investigate the relief of low back pain after hip arthroplasty in patients with hip joint and spinal degenerative diseases, and to discuss the effects of unilateral and bilateral hip surgery on the relief of low back pain.

Methods

In this retrospective study, we followed 153 patients (69 males and 84 females, age: 43–88 years) who had undergone total hip arthroplasty (THA) via a posterolateral approach and also suffered from lumbar degenerative diseases in the period of 2009 to 2019. The inclusion criteria were: (i) patients who had been diagnosed with severe hip degenerative disease and also been diagnosed with lumbar degenerative disease; (ii) patients who had undergone THA surgery; and (iii) patients who were retrospectively recruited. The exclusion criteria were: (i) patients who had undergone lumbar fusion or internal fixation surgery; or (ii) patients who had vascular claudication, history of major trauma, diabetic polyneuropathy, lumbar and pelvic infections, tumor diseases; (iii) or patients who had undergone THA because of femoral neck fracture or ankylosing spondylitis. The improvement of hip joint function and the relief of low back pain (LBP) were studied, and the effect of unilateral and bilateral THA on the relief of LBP were discussed. Hip pain and function were evaluated by the Harris Hip Score (HHS), LBP was evaluated by Visual Analog Scale (VAS), and lumbar function was evaluated by the Japanese Orthopaedic Association (JOA) scoring system.

Results

The average follow‐up time was 44.3 months (24–108 months). All patients recovered smoothly without complications. The LBP VAS of 153 patients decreased from 4.13 ± 1.37 preoperatively to 1.90 ± 1.44 postoperatively. The average HHS increased from 45.33 ± 13.23 preoperatively to 86.44 ± 7.59 postoperatively at the latest follow‐up. According to Japanese Orthopaedic Association scoring system, the proportion of patients with good response to treatment in these 153 patients reached 93.46%. LBP VAS decreased from 4.18 ± 1.38 preoperatively to 1.95 ± 1.49 postoperatively in unilateral group and from 3.94 ± 1.32 preoperatively to 1.73 ± 1.23 postoperatively in bilateral group, respectively. There were only nine patients with persistent or aggravated LBP after operation. Among them, six patients underwent subsequent lumbar surgery (five patients had pain relieved after reoperation and one patient had not) and the other three patients chose conservative treatment for pain.

Conclusion

THA can relieve LBP while relieving hip pain and restoring hip function in patients with both hip and lumbar degenerative disease, thus possibly avoiding further spinal surgery.

Applying the hip-spine relationship in total hip arthroplasty

Total hip arthroplasty dislocations that occur inside Lewinnek's anatomical safe zone represent a need to better understand the hip-spine relationship. Unfortunately, the use of obtuse and redundant terminology to describe the hip-spine relationship has made it a relatively inaccessible topic in orthopaedics. However, with a few basic definitions and principles, the hip-spine relationship can be simplified and understood to prevent unnecessary dislocations following total hip arthroplasty.In the following text, we use common language to define a normal and abnormal hip-spine relationship, present an algorithm for recognising and treating a high-risk hip-spine patient, and discuss several common, high-risk hip-spine pathologies to apply these concepts. Simply, high-risk hip-spine patients often require subtle adjustments to acetabular anteversion based on radiographic evaluations and should also be considered for a high-offset stem, dual-mobility articulation, or large femoral head for additional protection against instability and dislocation.

Relationship between hip joint proximity area and sagittal balance parameters: an upright computed tomography study

PURPOSE

A close relationship between sagittal spinal alignment and hip osteoarthritis (OA) has been documented. This study aimed to examine the relationship between hip joint proximity area and sagittal balance parameters in healthy subjects.

METHODS

This prospective study enrolled 47 healthy volunteers who underwent 320-detector row upright computed tomography. Acquired data were reconstructed in a virtual three-dimensional space. The proximity area was determined by < 1 mm of the Hausdorff distance between the acetabulum and the femoral head. Volunteers were divided into the anterior and posterior proximity groups depending on the position of the closest area. Sagittal balance parameters [sagittal vertical axis (SVA), T1 spinopelvic inclination (T1-SPi), T1-pelvic angle, pelvic tilt, sacral slope, pelvic incidence, lumbar lordosis, thoracic kyphosis), offset distance between the centre of the acoustic meati (CAM) and C7 plumb line (CAM-C7-offset), and offset distance between the CAM and hip axis (HA) (CAM-HA-offset)] were compared between the two groups using independent sample t test.

RESULTS

The anterior proximity group (n = 24) had higher SVA (p = 0.016) and T1-Spi (p = 0.015) than the posterior proximity group (n = 23). CAM-HA-offset was higher in the posterior than in the anterior proximity group (p < 0.000). There was no difference in other parameters (p > 0.05).

CONCLUSION

The anterior proximity group had a positive anterior spinal balance; the posterior proximity group may have a more posterior gravity line than the hip joint centre. The anterior spinal balance may contribute to the anterior loading of the hip joint, with known relation with the initiation and onset of hip OA.

Obesity Alters Spinopelvic Alignment Changes From Standing to Relaxed Sitting: the Influence of the Soft-tissue Envelope

Background

Changes in spinopelvic and lower extremity alignment between standing and relaxed sitting have important clinical implications with regard to stability of total hip arthroplasty. This study aimed to analyze the effect of body mass index (BMI) on lumbopelvic alignment and motion at the hip joint.

Methods

A retrospective review of patients who underwent full-body stereoradiographs in standing and relaxed sitting for total hip arthroplasty planning was conducted. Spinopelvic parameters measured included spinopelvic tilt (SPT), pelvic incidence (PI), lumbar lordosis (LL), PI minus LL (PI-LL), proximal femoral shaft angle (PFSA), and standing-to-sitting hip range of motion. Propensity score matching controlled for age, gender, PI, and hip ostoarthritis grade. Patients were stratified into normal (NORMAL; BMI, 18.5-24.9), overweight (OW; 25.0-29.9), and obese (OB; 30.0-34.9) groups. Alignment parameters were compared using one-way analysis of variance.

Results

There were 84 patients in each group after propensity score matching. Standing alignment between BMI groups was similar for all parameters (P > .05) except for PFSA (P < .001). Significant differences were noted for sitting alignment between patients who are NORMAL, OW, and OB in: SPT (P = .007), PI-LL (P = .018), and LL (P = .029). PFSA between groups was not significantly different (P > .05). Significant differences were found for sitting-to-standing alignment across groups in PFSA change (P < .001), SPT change (P = .006), PI-LL change (P = .005), LL change (P = .037), and hip flexion (P < .001).

Conclusions

Significant differences in sitting and standing-to-sitting change in lumbopelvic alignment based on BMI suggest obese patients recruit more posterior spinopelvic tilt when sitting to compensate for soft-tissue impingement that occurs anterior to the hip joint and limiting hip flexion.

Clinical phenotypes based on clinical prognostic factors in patients with secondary hip osteoarthritis: preliminary findings from a prospective cohort study

OBJECTIVES

Recently, several clinical prognostic factors for hip osteoarthritis (OA) progression such as spinal malalignment, reduced spinal mobility, and excessive daily cumulative hip loading have been identified. This study aimed to identify clinical phenotypes based on clinical prognostic factors in patients with secondary hip OA using data from prospective cohort studies and to define the clinical features of each phenotype.

METHODS

Fifty patients participated. Two-step cluster analysis was performed to identify the phenotypes using the following potential prognostic factors for hip OA progression: spinal inclination in standing, thoracolumbar spine mobility, daily cumulative hip moment, and minimum joint space width (JSW) at baseline. Comprehensive basic and clinical features (age, body mass index, hip pain, Harris hip score, JSW, radiographic hip morphology, hip impairments, spinal alignment and mobility, and gait-related variables) and ratio of progressors in 12 months were compared among the phenotypes using bootstrap method (unadjusted and adjusted for age).

RESULTS

Three phenotypes were identified and each phenotype was characterized as follows (P < 0.05): phenotype 1 (30%)-relatively young age and higher daily cumulative hip loading; phenotype 2 (42.0%)-relatively older age, reduced JSW, and less spinal mobility; and phenotype 3 (28.0%)-changed thoracic spine alignment and less spinal (especially in the thoracic spine) mobility. The ratio of progressors among the phenotypes was not statistically significantly different. These characteristics remained after adjustment for age.

CONCLUSION

Three phenotypes with similar progression risk were identified. This finding will help in designing treatment tailored to each phenotype for hip OA progression prevention.Key Points• Three phenotypes with similar progression risk were identified based on clinical prognostic factors.• Phenotype 1 was characterized by young age and higher daily cumulative hip loading.• Phenotype 2 was relatively old age and had reduced JSW and less spinal mobility.• Phenotype 3 had changed thoracic spine alignment and less thoracic spine mobility.

Spinopelvic Compensatory Mechanisms for Reduced Hip Motion (ROM) in the Setting of Hip Osteoarthritis

STUDY DESIGN

Retrospective review from a single institution.

OBJECTIVE

To investigate the effect of hip osteoarthritis (OA) on spinopelvic compensatory mechanisms as a result of reduced hip range of motion (ROM) between sitting and standing.

SUMMARY OF BACKGROUND DATA

Hip OA results in reduced hip ROM and contracture, causing pain during postural changes. Hip flexion contracture is known to reduce the ability to compensate for spinal deformity while standing; however, the effects of postural spinal alignment change between sitting and standing is not well understood.

METHODS

Sit-stand radiographs of patients without prior spinal fusion or hip prosthesis were evaluated. Hip OA was graded by Kellgren-Lawrence grades and divided into low-grade (LOA; grade 0-2) and severe (SOA; grade 3 or 4) groups. Radiographic parameters evaluated were pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), PI-LL, thoracic kyphosis (TK), SVA, T1-pelvic angle (TPA), T10-L2, proximal femoral shaft angle (PFSA), and hip flexion (PT change-PFSA change). Changes in sit-stand parameters were compared between LOA and SOA groups.

RESULTS

548 patients were included (LOA = 311; SOA = 237). After propensity score matching for age, body mass index, and PI, 183 LOA and 183 SOA patients were analyzed. Standing analysis demonstrated that SOA had higher SVA (31.1 vs. 21.7), lower TK (-36.2 vs. -41.1), and larger PFSA (9.1 vs. 7.4) (all p < .05). Sitting analysis demonstrated that SOA had higher PT (29.7 vs. 23.3), higher PI-LL (21.6 vs. 12.4), less LL (31.7 vs. 41.6), less TK (-33.2 vs. -38.6), and greater TPA (27.9 vs. 22.5) (all p < .05). SOA had less hip ROM from standing to sitting versus LOA (71.5 vs. 81.6) (p < .05). Therefore, SOA had more change in PT (15.2 vs. 7.3), PI-LL (20.6 vs. 13.7), LL (-21.4 vs. -13.1), and T10-L2 (-4.9 vs. -1.1) (all p < .001), allowing the femurs to change position despite reduced hip ROM. SOA had greater TPA reduction (15.1 vs. 9.6) and less PFSA change (86.7 vs. 88.8) compared with LOA (both p < .001).

CONCLUSIONS

Spinopelvic compensatory mechanisms are adapted for reduced hip joint motion associated with hip OA in standing and sitting.

LEVEL OF EVIDENCE

Level III.

Adult spinal deformity

Adult spinal deformity affects the thoracic or thoracolumbar spine throughout the ageing process. Although adolescent spinal deformities taken into adulthood are not uncommon, the most usual causes of spinal deformity in adults are iatrogenic flatback and degenerative scoliosis. Given its prevalence in the expanding portion of the global population aged older than 65 years, the disorder is of growing interest in health care. Physical examination, with a focus on gait and posture, along with radiographical assessment are primarily used and integrated with risk stratification indices to establish optimal treatment planning. Although non-operative treatment is regarded as the first-line response, surgical outcomes are considerably favourable. Global disparities exist in both the assessment and treatment of adults with spinal deformity across countries of varying incomes, which represents an area requiring further investigation. This Seminar presents evidence and knowledge that represent the evolution of data related to spinal deformity in adults over the past several decades.

Gait- and postural-alignment-related prognostic factors for hip and knee osteoarthritis: Toward the prevention of osteoarthritis progression

Osteoarthritis (OA) is a chronic progressive disease, and thus, prevention of this progression is an important issue. Currently, there is little evidence of the effect of exercise therapy for the prevention of hip and knee OA progression. An understanding of prognostic factors is the basis for the prevention of progression. Previous research indicates that in case of knee OA, abnormalities in knee alignment (varus or valgus) while standing, varus thrust during walking, increased knee flexion in the early stance phase, abnormal displacement of the femur in relation to the tibia, and an increase in knee adduction and flexion moment are risk factors for disease progression. At the same time, the prognostic factors in hip OA are anterior spinal inclination while standing, decreased mobility of the thoracolumbar spine, and increased cumulative hip loading during daily walking. Further research is required to investigate these prognostic factors, particularly the modifiable factors, to analyze the relationships between these factors, and to verify the structural and clinical efficacy of modifying these factors through interventions.

Gait- and Posture-Related Factors Associated With Changes in Hip Pain and Physical Function in Patients With Secondary Hip Osteoarthritis: A Prospective Cohort Study

OBJECTIVE

To identify gait- and posture-related factors associated with changes in hip pain and physical function in patients with hip osteoarthritis (OA).

DESIGN

Prospective cohort study.

SETTING

Clinical biomechanics laboratory of a university.

PARTICIPANTS

Consecutive sampling of female patients with mild-to-moderate secondary hip OA (N=30).

MAIN OUTCOME MEASURES

Hip pain (visual analog scale) and physical function (physical component summary of the Medical Outcomes Study 36-Item Short-Form Health Survey) were measured at baseline and 12 months later. With changes in hip pain and physical function as dependent variables, linear regression analyses were performed with gait- and posture-related factors as independent variables with and without adjustment for age, joint space width, and hip pain or physical function at baseline. Posture-related factors included angles of thoracic kyphosis, lumbar lordosis, sacral inclination, spinal inclination, and spinal mobility. Gait-related factors were walking speed, steps per day, joint angles, external hip joint moment impulses, and daily cumulative hip moments.

RESULTS

Multiple linear regression analyses showed that limited hip extension (adjusted standardized B coefficient [95% confidence interval]: -0.52 [-0.88 to -0.17]) and limited external rotation angles (-0.51 [-0.85 to -0.18]) during walking were associated with the worsening of hip pain. An increased thoracic kyphosis (-0.54 [-0.99 to -0.09]), less sacral anterior tilt (0.40 [0.01-0.79]), reduced thoracic spine mobility (0.59 [0.23-0.94]), less steps per day (0.53 [0.13-0.92]), and a slower walking speed (0.45 [0.04-0.86]) were associated with deterioration in physical function.

CONCLUSIONS

Gait- and posture-related factors should be considered when assessing risk and designing preventive interventions for the clinical progression of secondary hip OA.