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Huang CH, Aydemir B, Jalasutram A, Kabir I, Foucher KC. Impact of step length asymmetry on walking energetics in women with hip Osteoarthritis: A pilot study. J Biomech 2021; 129:110862. [PMID: 34794042 DOI: 10.1016/j.jbiomech.2021.110862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 11/03/2021] [Accepted: 11/03/2021] [Indexed: 10/19/2022]
Abstract
A step length difference between the involved and uninvolved limbs in participants with hip osteoarthritis (OA) has been reported. The implications of step length asymmetry on other aspects of walking mechanics are as yet unknown. The objective of the current study was to evaluate the consequences of step length asymmetry on motion of the center of mass (COM) and energy cost of walking. We hypothesized that (i) increased step length asymmetry is associated with decreased mechanical energy exchange; (ii) decreased mechanical energy exchange is associated with increased O2 cost; (iii) increased step length asymmetry is associated with increased oxygen O2 cost during walking in women with hip OA. We evaluated 24 women with unilateral hip OA using motion analysis as participants walked on a treadmill at self-selected speeds. Kinematic data were collected to compute step length asymmetry and mechanical energy exchange through the motion of COM. We also used a portable metabolic system to measure the energy cost of walking simultaneously. We used Pearson correlations and linear regression to test our hypotheses. We found that more asymmetric step lengths were associated with lower mechanical energy exchange (R2 = 0.231, p = 0.017). More mechanical energy exchange was associated with lower O2 cost during gait (R2 = 0.284, p = 0.009). Mechanical energy exchange predicted 54.5% of the variance in O2 cost after adjusting for self-selected walking speed. Findings suggest that modifying step length asymmetry could enhance metabolic gait efficiency indirectly by improving mechanical energy exchange in participants with hip OA.
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Affiliation(s)
- Chun-Hao Huang
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, USA.
| | - Burcu Aydemir
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, USA
| | | | - Ike Kabir
- Department of Bioengineering, University of Illinois at Chicago, USA
| | - Kharma C Foucher
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, USA
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2
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Iwasa M, Ando W, Uemura K, Hamada H, Takao M, Sugano N. Pelvic incidence is not associated with the development of hip osteoarthritis. Bone Joint J 2021; 103-B:1656-1661. [PMID: 34719275 DOI: 10.1302/0301-620x.103b11.bjj-2021-0472.r1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
AIMS Pelvic incidence (PI) is considered an important anatomical parameter for determining the sagittal balance of the spine. The contribution of an abnormal PI to hip osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the relationship between PI and hip OA, and the difference in PI between hip OA without anatomical abnormalities (primary OA) and hip OA with developmental dysplasia of the hip (DDH-OA). METHODS In this study, 100 patients each of primary OA, DDH-OA, and control subjects with no history of hip disease were included. CT images were used to measure PI, sagittal femoral head coverage, α angle, and acetabular anteversion. PI was also subdivided into three categories: high PI (larger than 64.0°), medium PI (42.0° to 64.0°), and low PI (less than 42.0°). The anterior centre edge angles, posterior centre edge angles, and total sagittal femoral head coverage were measured. The correlations between PI and sagittal femoral head coverage, α angle, and acetabular anteversion were examined. RESULTS No significant difference in PI was observed between the three groups. There was no significant difference between the groups in terms of the category distribution of PI. The DDH-OA group had lower mean sagittal femoral head coverage than the other groups. There were no significant correlations between PI and other anatomical factors, including sagittal femoral head coverage, α angle, and acetabular anteversion. CONCLUSION No associations were found between mean PI values or PI categories and hip OA. Furthermore, there was no difference in PI between patients with primary OA and DDH-OA. From our evaluation, we found no evidence of PI being an independent factor associated with the development of hip OA. Cite this article: Bone Joint J 2021;103-B(11):1656-1661.
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Affiliation(s)
- Makoto Iwasa
- Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Wataru Ando
- Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Keisuke Uemura
- Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hidetoshi Hamada
- Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masaki Takao
- Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Nobuhiko Sugano
- Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Osaka, Japan
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Abdullah AH, Todo M. Prediction of Bone Mineral Density (BMD) Adaptation in Pelvis-Femur Model with Hip Arthroplasties. J Funct Biomater 2021; 12:jfb12030049. [PMID: 34564198 PMCID: PMC8482249 DOI: 10.3390/jfb12030049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/27/2021] [Accepted: 08/29/2021] [Indexed: 11/20/2022] Open
Abstract
The prediction of bone remodeling behaviour is a challenging factor in encouraging the long-term stability of hip arthroplasties. The presence of femoral components modifies the biomechanical environment of the bone and alters the bone growth process. Issues of bone loss and gait instability on both limbs are associated with the remodeling process. In this study, finite element analysis with an adaptive bone remodeling algorithm was used to predict the changes in bone mineral density following total hip and resurfacing hip arthroplasty. A three-dimensional model of the pelvis–femur was constructed from computed tomography (CT-based) images of a 79-year-old female patient with hip osteoarthritis. The prosthesis stem of the total hip arthroplasty was modelled with a titanium alloy material, while the femoral head had alumina properties. Meanwhile, resurfacing of the hip implant was completed with a cobalt-chromium material. Contact between the components and bone was designed to be perfectly bonded at the interface. Results indicate that the bone mineral density was modified over five years on all models, including hip osteoarthritis. The changes of BMD were predicted as being high between year zero and year one, especially in the proximal region. Changes were observed to be minimal in the following years. The bone remodeling process was also predicted for the non-operated femur. However, the adaptation was lower compared to the operated limbs. The reduction in bone mineral density suggested the bone loss phenomenon after a few years.
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Affiliation(s)
- Abdul Halim Abdullah
- School of Mechanical Engineering, College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
- Correspondence:
| | - Mitsugu Todo
- Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-koen, Kasuga 816-8580, Japan;
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Sex differences in proximal femur shape: findings from a population-based study in adolescents. Sci Rep 2020; 10:4612. [PMID: 32165724 PMCID: PMC7067853 DOI: 10.1038/s41598-020-61653-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Accepted: 02/27/2020] [Indexed: 11/18/2022] Open
Abstract
Hip shape is an important determinant of hip osteoarthritis (OA), which occurs more commonly in women. However, it remains unclear to what extent differences in OA prevalence are attributed to sex differences in hip shape. Here, we explore sex differences in proximal femur shape in a cohort of adolescents. Hip morphology was quantified using hip DXA scans from the Avon Longitudinal Study of Parents and Children. Independent modes of variation (hip shape mode (HSM) scores) were generated for each image using an adult reference statistical shape model (N = 19,379). Linear regression was used to examine sex differences for the top ten HSMs, adjusting for age, height, lean and fat mass. Complete outcome and covariate data were available for 4,428 and 4,369 participants at ages 14 and 18 years, respectively. Several HSMs showed sex differences at both time points. The combined effect of sex on hip shape at age 14 reflected flatter femoral head and smaller lesser trochanter in females compared with males and, following adjustment for age and body size, these differences became more pronounced. At age 18, smaller lesser trochanter and femoral neck width (FNW) in females still remained although differences in femoral head, femoral shaft and FNW were largely attenuated following adjustment. Sexual dimorphism in proximal femur shape can be discerned in adolescence and early adulthood. Observed differences in proximal femur shape, particularly at age 14 were largely independent of body size, however to what extent differences in hip shape in early life play a role in predisposing to hip OA in later life remains to be determined.
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Hip stress distribution - Predictor of dislocation in hip arthroplasties. A retrospective study of 149 arthroplasties. PLoS One 2019; 14:e0225459. [PMID: 31747433 PMCID: PMC6867650 DOI: 10.1371/journal.pone.0225459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 11/05/2019] [Indexed: 12/14/2022] Open
Abstract
Dislocation after hip arthroplasty is still a major concern. Recent study of the volumetric wear of the cup has suggested that stresses studied in a one-legged stance model could predispose arthroplasty dislocation. The aim of this work was to study whether biomechanical parameters of contact stress distribution in total hip arthroplasty during a neutral hip position can predict a higher possibility of the arthroplasty dislocating. Biomechanical parameters were determined using 3-dimensional mathematical models of the one-legged stance within the HIPSTRESS method. Geometrical parameters were measured from standard anteroposterior X-ray images of the pelvis and proximal femora. Fifty-five patients subjected to total hip arthroplasty that later suffered dislocation of the head and, for comparison, ninety-four total hip arthroplasties that were functional at least 10 years after the implantation, were included in the study. Arthroplasties that suffered dislocation had on average a 6% higher resultant hip force than the control group (p = 0.004), 11% higher peak stress on the load-bearing area (p = 0.001) and a 50% more laterally positioned stress pole (p = 0.026), all parameters being less favorable in the group of unstable arthroplasties. There was no statistically significant difference in the gradient index or in the functional angle of the weight bearing. Our study showed that arthroplasties that show a tendency to push the head out of the cup in the representative body position—the one-legged stance—are prone to dislocation. An unfavorable resultant hip force, peak stress on the load bearing and laterally positioned stress pole are predictors of arthroplasty dislocation.
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Moličnik A, Janša J, Kocjančič B, Kralj-Iglič V, Dolinar D. Secondary hip dysplasia increases risk for early coxarthritis after Legg-Calve-Perthes disease. A study of 255 hips. Comput Methods Biomech Biomed Engin 2019; 22:1107-1115. [PMID: 31429314 DOI: 10.1080/10255842.2019.1634193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The biomechanical parameters of the hip joint articular surface were analysed in 141 adult hips after Legg-Calve Perthes Disease, and 114 contralateral unaffected hips (controls), by using HIPSTRESS mathematical models. Geometrical parameters, assessed from anteroposterior and axial radiograms, were used as input to models for resultant hip force and contact hip stress. Results confirm previous indications that head enlargement after the Legg-Calve-Perthes Disease compensates the values of hip stress. Furthermore, it was found that an increased risk for coxarthritis development after the disease is secondary to concomitant hip dysplasia, with considerable and statistically significantly lower centre-edge angle and unfavourable distribution of stress.
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Affiliation(s)
- Andrej Moličnik
- Department of Orthopaedic Surgery, University Medical Centre Maribor , Maribor , Slovenia
| | - Jošt Janša
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana , Ljubljana , Slovenia
| | - Boštjan Kocjančič
- Department of Orthopaedic Surgery, University Medical Centre Ljubljana , Ljubljana , Slovenia
| | - Veronika Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Health Sciences, University of Ljubljana , Ljubljana , Slovenia
| | - Drago Dolinar
- Department of Orthopaedic Surgery, University Medical Centre Ljubljana , Ljubljana , Slovenia
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Escudier JC, Ollivier M, Donnez M, Parratte S, Lafforgue P, Argenson JN. Superimposition of maximal stress and necrosis areas at the top of the femoral head in hip aseptic osteonecrosis. Orthop Traumatol Surg Res 2018; 104:353-358. [PMID: 29462725 DOI: 10.1016/j.otsr.2018.01.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 01/05/2018] [Accepted: 01/10/2018] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Recent reports described possible mechanical factors in the development and aggravation of osteonecrosis of the femoral head (OFH), but these have yet to be confirmed on dedicated mechanical study. We therefore developed a 3D finite element model based on in-vivo data from patients with incipient OFH, with a view to determining whether the necrosis area was superimposed on the maximal stress area on the femoral head. HYPOTHESIS The location of the necrosis area is determined by stress on the femoral head. MATERIAL AND METHOD All patients from the rheumatology department with early stage OFH in our center were investigated. Analysis of CT scans showed stress distribution on the head by 3D finite elements models, enabling determination of necrosis volume within the maximal stress area and of the percentage intersection of necrosis within the stress area (%I n/s: necrosis volume in stress area divided by total stress area volume and multiplied by 100) and of stress within the necrosis area (%I s/n: stress volume in necrosis area divided by total necrosis area volume and multiplied by 100). RESULTS Nineteen of the 161 patients assessed retrospectively for the period between 2006 and 2015 had incipient unilateral OFH, 10 of whom (4 right, 6 left) had CT scans of sufficient quality for inclusion. Mean age was 52 years (range, 37-81 years). Mean maximal stress was 1.63MPa, mean maximal exported stress volume was 2,236.9 mm3 and mean necrosis volume 6,291.1 mm3. Mean %I n/s was 83% and mean %I s/n 35%, with no significant differences according to gender, age, side or stress volume. There was a strong inverse correlation between necrosis volume and %I s/n (R2=-0.92) and a strong direct correlation between exported stress volume and %I s/n (R2=0.55). %I s/n was greater in small necrosis (<7,000mm3). CONCLUSION OFH seems to develop within the maximal stress area on the femoral head. The present results need confirmation by larger-scale studies. We consider it essential to take account of these mechanical parameters to reduce failure rates in conservative treatment of OFH. LEVEL OF EVIDENCE IV.
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Affiliation(s)
- J-C Escudier
- ISM UMR 7287, CNRS, Aix-Marseille University, 13288 Marseille cedex 09, France; Department of Orthopedic Surgery and Traumatology, Institute of Movement and Locomotion, Saint-Marguerite Hospital, 270, boulevard Sainte-Marguerite BP 29, 13274 Marseille, France
| | - M Ollivier
- ISM UMR 7287, CNRS, Aix-Marseille University, 13288 Marseille cedex 09, France; Department of Orthopedic Surgery and Traumatology, Institute of Movement and Locomotion, Saint-Marguerite Hospital, 270, boulevard Sainte-Marguerite BP 29, 13274 Marseille, France.
| | - M Donnez
- ISM UMR 7287, CNRS, Aix-Marseille University, 13288 Marseille cedex 09, France
| | - S Parratte
- ISM UMR 7287, CNRS, Aix-Marseille University, 13288 Marseille cedex 09, France; Department of Orthopedic Surgery and Traumatology, Institute of Movement and Locomotion, Saint-Marguerite Hospital, 270, boulevard Sainte-Marguerite BP 29, 13274 Marseille, France
| | - P Lafforgue
- ISM UMR 7287, CNRS, Aix-Marseille University, 13288 Marseille cedex 09, France; Department of Rheumatology, Institute of Movement and Locomotion, Saint-Marguerite Hospital, 270, boulevard Sainte-Marguerite BP 29, 13274 Marseille, France
| | - J-N Argenson
- ISM UMR 7287, CNRS, Aix-Marseille University, 13288 Marseille cedex 09, France; Department of Orthopedic Surgery and Traumatology, Institute of Movement and Locomotion, Saint-Marguerite Hospital, 270, boulevard Sainte-Marguerite BP 29, 13274 Marseille, France
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Gait Characteristics, Symptoms, and Function in Persons With Hip Osteoarthritis: A Longitudinal Study With 6 to 7 Years of Follow-up. J Orthop Sports Phys Ther 2015; 45:539-49. [PMID: 25996360 DOI: 10.2519/jospt.2015.5441] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
STUDY DESIGN Longitudinal laboratory study. OBJECTIVES (1) To compare gait characteristics between individuals with early-stage hip osteoarthritis who underwent total hip replacement (THR) and those who did not undergo THR, and (2) to evaluate whether gait characteristics, function, and symptoms declined among individuals who did not undergo THR during a 6- to 7-year follow-up. BACKGROUND The natural history of symptoms, function, and gait changes secondary to hip osteoarthritis, including potential differences at an early stage of disease, is unknown. METHODS Forty-three individuals (mean age, 58.9 years) with radiographic and symptomatic hip osteoarthritis participated. Outcome measures included 3-D gait analysis; self-reported pain, stiffness, and function; hip range of motion; and the six-minute walk test. Baseline comparisons between individuals who later underwent THR and those who did not undergo THR were made using independent t tests or Mann-Whitney U tests. Comparisons of baseline measures and 6- to 7-year follow-up for the nonoperated individuals were conducted with paired-samples t tests or Wilcoxon signed-rank tests (P<.05). RESULTS Twelve (27.9%) of the 43 individuals initially evaluated had not undergone THR at the 6- to 7-year follow-up. At baseline, these individuals had larger sagittal plane hip and knee joint excursions, larger joint space width, lower body mass index, and superior self-reported function compared with the individuals who later underwent THR. At the 6- to 7-year follow-up, the individuals who did not undergo THR exhibited no decline in gait characteristics, minimum joint space, or overall function. Furthermore, their self-reported pain had significantly decreased (P = .024). CONCLUSION Individuals who did not undergo THR during a 6- to 7-year follow-up period did not exhibit a decline in gait, function, or symptoms compared to those who underwent THR. These findings are suggestive of a phenotype of hip osteoarthritis with a very slow disease progression, particularly in regard to pain. LEVEL OF EVIDENCE Prognosis, level 1b.
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Satpathy J, Kannan A, Owen JR, Wayne JS, Hull JR, Jiranek WA. Hip contact stress and femoral neck retroversion: a biomechanical study to evaluate implication of femoroacetabular impingement. J Hip Preserv Surg 2015; 2:287-94. [PMID: 27011851 PMCID: PMC4765305 DOI: 10.1093/jhps/hnv040] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 04/24/2015] [Accepted: 05/17/2015] [Indexed: 11/12/2022] Open
Abstract
The current literature on femoroacetabular impingement (FAI) is focused on acetabular orientation and femoral head asphericity, with little emphasis on the effect of version of the femoral neck. A biomechanical model was developed to determine the causative effect, if any, of femoral retroversion on hip contact stress and, if present, delineate the type of FAI with femoral neck retroversion. Five pairs of cadaveric hips (n = 10) were tested by loading the hip in 90° of flexion and measured the peak joint pressure and the location of the peak joint pressure. The experiment was repeated after performing a subtrochanteric osteotomy and retroverting the proximal femur by 10°. Ten hips were successfully tested, with one hip excluded due to an outlier value for peak joint pressure. Retroversion of the proximal femur significantly increased the magnitude of mean peak joint pressure. With retroversion, the location of the peak joint pressure was shifted posteroinferiorly in all cases. In conclusion, femoral neck retroversion increases peak joint pressure in the flexed position and may act as a cause of femoroacetabular impingement. The location of peak joint pressure suggests a pincer-type impingement with retroversion. The version of femoral neck should be assessed as a possible causative factor in patients with FAI, especially those with pincer-type impingement.
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Affiliation(s)
- Jibanananda Satpathy
- Orthopaedic Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Arun Kannan
- Orthopaedic Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - John R Owen
- Orthopaedic Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Jennifer S Wayne
- Orthopaedic Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - Jason R Hull
- Orthopaedic Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
| | - William A Jiranek
- Orthopaedic Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
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Xu C, Yan YB, Zhao X, Wen XX, Shang L, Huang LY, Lei W. Pedobarographic Analysis Following Pemberton's Pericapsular Osteotomy for Unilateral Developmental Dysplasia of the Hip: An Observational Study. Medicine (Baltimore) 2015; 94:e932. [PMID: 26061319 PMCID: PMC4616480 DOI: 10.1097/md.0000000000000932] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Successful clinical and radiographic outcomes have been reported in patients with unilateral developmental dysplasia of the hip (DDH) following Pemberton pericapsular osteotomy (PPO). However, residual gait deviations are seen in both the affected and unaffected limbs. To date it is not known whether these deviations result in abnormal plantar pressure in such patients. This study investigated this possibility by performing pedobarographic, clinical, and radiographic examinations after PPO in 20 patients (age: 102.5 ± 19.0 months) with unilateral DDH who underwent PPO at 34.2 ± 9.8 months of age. Plantar pressure was evaluated using the Footscan pressure plate (RsScan International, Olen, Belgium). Each foot was subdivided into 10 zones and peak pressure, force-time integral as a percentage of total FTI, and contact time as a percentage of total stance time was estimated. The minimum duration of follow-up was 24 months (mean: 68.3 ± 20.3 months). The data were compared with 20 age- and weight-matched healthy controls. Despite clinical and radiographic examinations showing satisfactory results according to modified McKay and Severin criteria, significant differences in plantar pressure parameters were identified between the affected limbs, the unaffected limbs, and normal controls. No significant differences were found between patients classified as "excellent or good" and those rated as "fair" according to the modified Severin criteria. Pedobarographic results showed the existence of the residual plantar pressure deviations during walking in patients treated with PPO for unilateral DDH. Longer follow-up will be needed to more fully evaluate the effect of these deviations on gait.
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Affiliation(s)
- Chao Xu
- From Department of Orthopaedics, Xijing Hospital (CX, YBY, XZ, XXW, LYH, WL); and Department of Health Statistics, Faculty of Preventive Medicine, the Fourth Military Medical University, Xi'an, PR China (LS)
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11
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Lewis CL, Garibay EJ. Effect of increased pushoff during gait on hip joint forces. J Biomech 2014; 48:181-5. [PMID: 25468661 DOI: 10.1016/j.jbiomech.2014.10.033] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/23/2014] [Accepted: 10/31/2014] [Indexed: 11/19/2022]
Abstract
Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to "push more with your foot when you walk". We collected motion data of markers placed on the subjects' trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to "push more with your foot when you walk" reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces were 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain.
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Affiliation(s)
- Cara L Lewis
- Department of Physical Therapy & Athletic Training, College of Health & Rehabilitation Sciences: Sargent College, Boston University, 635 Commonwealth Avenue, Boston, MA 02215, USA.
| | - Erin J Garibay
- Center for Motion Analysis, Connecticut Children׳s Medical Center, Farmington, CT, USA
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12
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Rijavec B, Košak R, Daniel M, Kralj-Iglič V, Dolinar D. Effect of cup inclination on predicted contact stress-induced volumetric wear in total hip replacement. Comput Methods Biomech Biomed Engin 2014; 18:1468-73. [PMID: 24830356 DOI: 10.1080/10255842.2014.916700] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In order to increase the lifetime of the total hip endoprosthesis, it is necessary to understand mechanisms leading to its failure. In this work, we address volumetric wear of the artificial cup, in particular the effect of its inclination with respect to the vertical. Volumetric wear was calculated by using mathematical models for resultant hip force, contact stress and penetration of the prosthesis head into the cup. Relevance of the dependence of volumetric wear on inclination of the cup (its abduction angle ϑA) was assessed by the results of 95 hips with implanted endoprosthesis. Geometrical parameters obtained from standard antero-posterior radiographs were taken as input data. Volumetric wear decreases with increasing cup abduction angle ϑA. The correlation within the population of 95 hips was statistically significant (P = 0.006). Large cup abduction angle minimises predicted volumetric wear but may increase the risk for dislocation of the artificial head from the cup in the one-legged stance. Cup abduction angle and direction of the resultant hip force may compensate each other to achieve optimal position of the cup with respect to wear and dislocation in the one-legged stance for a particular patient.
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Affiliation(s)
- B Rijavec
- a Laboratory of Clinical Biophysics, Faculty of Health Sciences , University of Ljubljana , Zdravstvena 5, SI-1000 Ljubljana , Slovenia
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13
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Eitzen I, Fernandes L, Nordsletten L, Snyder-Mackler L, Risberg MA. Weight-bearing asymmetries during Sit-To-Stand in patients with mild-to-moderate hip osteoarthritis. Gait Posture 2014; 39:683-8. [PMID: 24238750 DOI: 10.1016/j.gaitpost.2013.09.010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 07/31/2013] [Accepted: 09/15/2013] [Indexed: 02/02/2023]
Abstract
The Sit-To-Stand (STS) transition is a mechanically demanding task that may pose particular challenges for individuals with lower limb osteoarthritis (OA). Biomechanical features of STS have been investigated in patients with OA, but not in patients with early stage hip OA. The purpose of this study was to explore inter-limb weight-bearing asymmetries (WBA) and selected kinematic and kinetic variables during STS in patients with mild-to-moderate hip OA compared with healthy controls. Twenty-one hip OA patients and 23 controls were included in the study. Sagittal and frontal plane kinematic and kinetic data were collected using an eight-camera motion analysis system synchronized with two force plates embedded in the floor. There were no distinctive biomechanical alterations in sagittal or frontal plane kinematics or kinetics, movement time, or time to reach peak ground reaction force (GRF) in hip OA patients compared with controls. However, the hip OA patients revealed a distinct pattern of WBA compared with the controls, in unloading their involved limb by 18.4% at peak GRF. These findings indicate that patients with early stage hip OA are not yet forced into a stereotypical movement strategy for STS; however, the observed pattern of WBA requires clinical attention.
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Affiliation(s)
- Ingrid Eitzen
- Norwegian Research Centre for Active Rehabilitation, Oslo, Norway; Department of Orthopaedics, Oslo University Hospital, Oslo, Norway.
| | - Linda Fernandes
- Norwegian Research Centre for Active Rehabilitation, Oslo, Norway; Department of Orthopaedic Surgery and Traumatology, Odense University Hospital, Odense, Denmark.
| | - Lars Nordsletten
- Department of Orthopaedics, Oslo University Hospital, Oslo, Norway.
| | | | - May Arna Risberg
- Norwegian Research Centre for Active Rehabilitation, Oslo, Norway; Norwegian School of Sport Sciences, Oslo, Norway.
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Kocjančič B, Moličnik A, Antolič V, Mavčič B, Kralj-Iglič V, Vengust R. Unfavorable hip stress distribution after Legg-Calvé-Perthes syndrome: a 25-year follow-up of 135 hips. J Orthop Res 2014; 32:8-16. [PMID: 24038236 DOI: 10.1002/jor.22479] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Accepted: 08/08/2013] [Indexed: 02/04/2023]
Abstract
To study the effect of hip and pelvis geometry on development of the hip after Perthes disease, we determined the resultant hip force and contact hip stress distribution in a population of 135 adult hips of patients who had been treated for Perthes disease in childhood. Contra-lateral hips with no record of disease were taken as the control population. Biomechanical parameters were determined by mathematical models for resultant hip force in one-legged stance and for contact hip stress, which use as an input the geometrical parameters assessed from anteroposterior radiographs. The mathematical model for stress was upgraded to account for the deviation of the femoral head shape from spherical. No differences were found in resultant hip force and in peak contact hip stress between the hips that were in childhood subject to Perthes disease and the control population, but a considerable (148%) and significant (p < 0.001) difference was found in the contact hip stress gradient index, expressing an unfavorable, steep decrease of contact stress at the lateral acetabular rim. This finding indicates an increased risk of early coxarthritis in hips subject to Perthes disease.
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Affiliation(s)
- Boštjan Kocjančič
- Department of Orthopaedic Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia
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15
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Lenzi T, Carrozza MC, Agrawal SK. Powered Hip Exoskeletons Can Reduce the User's Hip and Ankle Muscle Activations During Walking. IEEE Trans Neural Syst Rehabil Eng 2013; 21:938-48. [DOI: 10.1109/tnsre.2013.2248749] [Citation(s) in RCA: 143] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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16
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Damm P, Schwachmeyer V, Dymke J, Bender A, Bergmann G. In vivo hip joint loads during three methods of walking with forearm crutches. Clin Biomech (Bristol, Avon) 2013; 28:530-5. [PMID: 23643290 DOI: 10.1016/j.clinbiomech.2012.12.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 12/04/2012] [Accepted: 12/05/2012] [Indexed: 02/07/2023]
Abstract
BACKGROUND Patients with osteoarthritis, joint implants or fractures use crutches in order to reduce lower limb loading. However, insufficient information exists on how much the loading is then in fact reduced. This situation was studied by using seven patients who had instrumented hip implants. METHODS Part I: To investigate the effectiveness of forearm crutches, crutch and hip joint contact forces were measured in seven patients with instrumented hip prostheses. Additionally, the bending moments in the implant neck and torsion around its stem were determined. Reductions of peak loads during 3, 4, and 2-point gaits were compared with loads present when walking without crutches. Part II: This examines joint load reduction during a 4-point gait from one to 12 weeks post-operatively. FINDINGS Part I: During a 3, 4, and 2-point gait, the joint force was 17, 12, and 13% lower than it was while walking without crutches. The corresponding reductions of the bending moment were 16, 11, and 12%, while the maximum torque decreased by 19, 21, and 10%. Part II: The reductions of contact forces in comparison with walking without crutches were highest during the first 4 weeks after surgery. One and 4 weeks post-operatively, the force maximum was 21 and 8% lower than it was after 3 months. When compared with the initial values of the 1st week, crutch forces decreased by 28% in the 4th week and by 38% in the 3rd month. INTERPRETATION Average reductions of the joint load by more than 20% are achieved only during the first 4 post-operative weeks. Because fractures are in most cases relatively stable after 6 weeks, and bone ingrowth into implant interfaces is nearly finished after this time, a single crutch and a 2-point gait can be prescribed during the 5th and 6th post-operative week.
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Affiliation(s)
- Philipp Damm
- Julius Wolff Institute, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
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17
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Eitzen I, Fernandes L, Nordsletten L, Risberg MA. Sagittal plane gait characteristics in hip osteoarthritis patients with mild to moderate symptoms compared to healthy controls: a cross-sectional study. BMC Musculoskelet Disord 2012; 13:258. [PMID: 23256709 PMCID: PMC3542161 DOI: 10.1186/1471-2474-13-258] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 12/17/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Existent biomechanical studies on hip osteoarthritic gait have primarily focused on the end stage of disease. Consequently, there is no clear consensus on which specific gait parameters are of most relevance for hip osteoarthritis patients with mild to moderate symptoms. The purpose of this study was to explore sagittal plane gait characteristics during the stance phase of gait in hip osteoarthritis patients not eligible for hip replacement surgery. First, compared to healthy controls, and second, when categorized into two subgroups of radiographic severity defined from a minimal joint space of ≤/>2 mm. METHODS Sagittal plane kinematics and kinetics of the hip, knee and ankle joint were calculated for total joint excursion throughout the stance phase, as well as from the specific events initial contact, midstance, peak hip extension and toe-off following 3D gait analysis. In addition, the Western Ontario and McMaster Universities Osteoarthritis Index, passive hip range of motion, and isokinetic muscle strength of hip and knee flexion and extension were included as secondary outcomes. Data were checked for normality and differences evaluated with the independent Student's t-test, Welch's t-test and the independent Mann-Whitney U-test. A binary logistic regression model was used in order to control for velocity in key variables. RESULTS Fourty-eight hip osteoarthritis patients and 22 controls were included in the final material. The patients walked significantly slower than the controls (p=0.002), revealed significantly reduced joint excursions of the hip (p<0.001) and knee (p=0.011), and a reduced hip flexion moment at midstance and peak hip extension (p<0.001). Differences were primarily manifested during the latter 50% of stance, and were persistent when controlling for velocity. Subgroup analyses of patients with minimal joint space ≤/>2 mm suggested that the observed deviations were more pronounced in patients with greater radiographic severity. The biomechanical differences were, however, not reflected in self-reported symptoms or function. CONCLUSIONS Reduced gait velocity, reduced sagittal plane joint excursion, and a reduced hip flexion moment in the late stance phase of gait were found to be evident already in hip osteoarthritis patients with mild to moderate symptoms, not eligible for total hip replacement. Consequently, these variables should be considered as key features in studies regarding hip osteoarthritic gait at all stages of disease. Subgroup analyses of patients with different levels of radiographic OA further generated the hypothesis that the observed characteristics were more pronounced in patients with a minimal joint space ≤2 mm.
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Affiliation(s)
- Ingrid Eitzen
- The Norwegian Research Center for Active Rehabilitation (NAR)/Orthopaedic Department, Oslo University Hospital, Oslo, Norway
| | - Linda Fernandes
- The Norwegian Research Center for Active Rehabilitation (NAR)/Orthopaedic Department, Oslo University Hospital, Oslo, Norway
| | | | - May Arna Risberg
- The Norwegian Research Center for Active Rehabilitation/The Norwegian School of Sports Sciences/Orthopaedic Department, Oslo University Hospital, Oslo, Norway
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18
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Chang CF, Wang TM, Wang JH, Huang SC, Lu TW. Adolescents after Pemberton's osteotomy for developmental dysplasia of the hip displayed greater joint loading than healthy controls in affected and unaffected limbs during gait. J Orthop Res 2011; 29:1034-41. [PMID: 21308759 DOI: 10.1002/jor.21377] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 01/04/2011] [Indexed: 02/04/2023]
Abstract
Patients after reduced developmental dysplasia of the hip (DDH) are at higher than normal risk of developing avascular necrosis (AVN) of the femoral head and degenerative hip osteoarthritis (OA) that are closely related to abnormal loadings. We aimed to determine the lower limb loadings in adolescents after Pemberton's osteotomy for unilateral DDH. Eleven females (age: 10.6 ± 1.0 years), who had received Pemberton's osteotomy for unilateral DDH at 1.6 ± 0.5 years of age, and 12 age-matched healthy controls were studied using gait analysis. Compared to the normal controls, the patients were displayed greater peak axial forces at the hip, knee, and ankle in both limbs, with greater loading rates in the ground reaction force (GRF) and at the hips (p < 0.05 for all comparisons). The increased rates of repetitive loading around heel strike in both hips suggest that patients treated for unilateral DDH using Pemberton's osteotomy may be at higher risk of premature hip OA. The increased axial forces at the affected hip may be a contributing factor to the development of AVN of the femoral head in these patients, especially when incomplete coverage, insufficient congruency, and/or damaged articular surfaces remain after the osteotomy. Therefore, monitoring the loading condition at the hip is necessary for a more accurate assessment of the risk of developing joint pathology in patients after reduced DDH.
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Affiliation(s)
- Chu-Fen Chang
- Institute of Biomedical Engineering, National Taiwan University, No. 1, Section 1, Jen-Ai Road, Taipei 100, Taiwan
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19
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Lewis CL, Ferris DP. Invariant hip moment pattern while walking with a robotic hip exoskeleton. J Biomech 2011; 44:789-93. [PMID: 21333995 DOI: 10.1016/j.jbiomech.2011.01.030] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2010] [Revised: 01/01/2011] [Accepted: 01/26/2011] [Indexed: 11/15/2022]
Abstract
Robotic lower limb exoskeletons hold significant potential for gait assistance and rehabilitation; however, we have a limited understanding of how people adapt to walking with robotic devices. The purpose of this study was to test the hypothesis that people reduce net muscle moments about their joints when robotic assistance is provided. This reduction in muscle moment results in a total joint moment (muscle plus exoskeleton) that is the same as the moment without the robotic assistance despite potential differences in joint angles. To test this hypothesis, eight healthy subjects trained with the robotic hip exoskeleton while walking on a force-measuring treadmill. The exoskeleton provided hip flexion assistance from approximately 33% to 53% of the gait cycle. We calculated the root mean squared difference (RMSD) between the average of data from the last 15 min of the powered condition and the unpowered condition. After completing three 30-min training sessions, the hip exoskeleton provided 27% of the total peak hip flexion moment during gait. Despite this substantial contribution from the exoskeleton, subjects walked with a total hip moment pattern (muscle plus exoskeleton) that was almost identical and more similar to the unpowered condition than the hip angle pattern (hip moment RMSD 0.027, angle RMSD 0.134, p<0.001). The angle and moment RMSD were not different for the knee and ankle joints. These findings support the concept that people adopt walking patterns with similar joint moment patterns despite differences in hip joint angles for a given walking speed.
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Affiliation(s)
- Cara L Lewis
- Human Adaptation Laboratory, College of Health and Rehabilitation Sciences, Sargent College, Boston University, 635 Commonwealth Avenue, Boston, MA 02215, USA.
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20
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Recnik G, Vengust R, Kralj-Iglič V, Vogrin M, Krajnc Z, Kramberger S. Association between Sub-Clinical Acetabular Dysplasia and a Younger Age at Hip Arthroplasty in Idiopathic Osteoarthritis. J Int Med Res 2009; 37:1620-1625. [DOI: 10.1177/147323000903700541] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
Abstract
This retrospective study was designed to investigate whether sub-clinical acetabular dysplasia, defined by a reduced centre-edge angle of Wiberg, was associated with a younger age at hip arthroplasty in patients with idiopathic osteoarthritis (OA). Fifty-four patients with 69 performed arthroplasties and no previous referral for hip dysplasia were selected from a list of consecutive recipients of hip endoprostheses due to idiopathic OA. The centre-edge angle was measured from standard pelvic radiographs taken a mean of 5.1 years prior to the endoprosthesis operation when there were minimal signs of hip OA. The age at which hip arthroplasty was carried out was compared between those patients with low (20° − 35°) and those with high (≥ 35°) centre-edge angles. The mean age at hip arthroplasty was significantly younger in the group with centre-edge angles of 20° − 35° (65.6 years) compared with those with centre-edge angles ≥ 35° (69.2 years). These results suggest that sub-clinical acetabular dysplasia was associated with a younger age at hip arthroplasty in idiopathic OA.
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Affiliation(s)
- G Recnik
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
| | - R Vengust
- Department of Orthopaedic Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia
| | - V Kralj-Iglič
- Laboratory of Clinical Biophysics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - M Vogrin
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
| | - Z Krajnc
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
| | - S Kramberger
- Department of Orthopaedic Surgery, University Hospital Maribor, Maribor, Slovenia
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Recnik G, Kralj-Iglic V, Iglic A, Antolic V, Kramberger S, Rigler I, Pompe B, Vengust R. The role of obesity, biomechanical constitution of the pelvis and contact joint stress in progression of hip osteoarthritis. Osteoarthritis Cartilage 2009; 17:879-82. [PMID: 19162509 DOI: 10.1016/j.joca.2008.12.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2008] [Revised: 12/01/2008] [Accepted: 12/13/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The aim of our study was to explore whether earlier hip arthroplasty for idiopathic osteoarthritis (OA) might be explained by enlarged contact stress in the hip joint, and to what amount can that be attributed to obesity and biomechanical constitution of the pelvis. METHOD Fifty subjects were selected from a list of consecutive recipients of hip endoprosthesis due to idiopathic OA; standard pelvic radiographs made years prior to surgery were the main selection criteria. For 65 hips resultant hip force and peak contact hip stress normalized to the body weight (R/Wb and p(max)/Wb) were determined from the radiographs with the HIPSTRESS method. Body weight and body mass index (BMI) were obtained with an interview. Regression analysis was used to correlate parameters of obesity (body weight, BMI), biomechanical constitution of the pelvis (R/Wb, p(max)/Wb) and mechanical loading within the hip joint (R, p(max)) with age at hip arthroplasty. RESULTS Younger age at hip arthroplasty was associated with higher body weight (P=0.009), higher peak contact hip stress normalized to the body weight - p(max)/Wb (P=0.019), higher resultant hip force -R (P=0.027) and larger peak contact hip stress - p(max) (P<0.001), but not with BMI (P=0.121) or R/Wb (P=0.614). CONCLUSION Our results suggest that enlarged contact stress (p(max)) plays an important role in rapid progression of hip OA with both obesity (increased body weight) and unfavorable biomechanical constitution of the pelvis (greater p(max)/Wb) contributing.
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Affiliation(s)
- G Recnik
- Department of Orthopedic Surgery, University Hospital Maribor, Maribor, Slovenia.
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Lewis CL, Ferris DP. Walking with increased ankle pushoff decreases hip muscle moments. J Biomech 2008; 41:2082-9. [PMID: 18606419 DOI: 10.1016/j.jbiomech.2008.05.013] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 05/09/2008] [Accepted: 05/11/2008] [Indexed: 11/15/2022]
Abstract
In a simple bipedal walking model, an impulsive push along the trailing limb (similar to ankle plantar flexion) or a torque at the hip can power level walking. This suggests a tradeoff between ankle and hip muscle requirements during human gait. People with anterior hip pain may benefit from walking with increased ankle pushoff if it reduces hip muscle forces. The purpose of our study was to determine if simple instructions to alter ankle pushoff can modify gait dynamics and if resulting changes in ankle pushoff have an effect on hip muscle requirements during gait. We hypothesized that changes in ankle kinetics would be inversely related to hip muscle kinetics. Ten healthy subjects walked on a custom split-belt force-measuring treadmill at 1.25m/s. We recorded ground reaction forces and lower extremity kinematic data to calculate joint angles and internal muscle moments, powers and angular impulses. Subjects walked under three conditions: natural pushoff, decreased pushoff and increased pushoff. For the decreased pushoff condition, subjects were instructed to push less with their feet as they walked. Conversely, for the increased pushoff condition, subjects were instructed to push more with their feet. As predicted, walking with increased ankle pushoff resulted in lower peak hip flexion moment, power and angular impulse as well as lower peak hip extension moment and angular impulse (p<0.05). Our results emphasize the interchange between hip and ankle kinetics in human walking and suggest that increased ankle pushoff during gait may help to compensate for hip muscle weakness or injury and reduce hip joint forces.
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Affiliation(s)
- Cara L Lewis
- Division of Kinesiology, University of Michigan, 401 Washtenaw Avenue, Ann Arbor, MI 48109-2214, USA.
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