Hip Osteoarthritis Group Research Articles

Mobility Requirements and Joint Loading during Straight Walking and 90° Turns in Healthy Older People and Those with Hip Osteoarthritis.

Background/Objectives: Hip mobility and joint loading in hip osteoarthritis (HOA) patients are mostly assessed during straight walking. Yet, mobility limitations in the frontal and transverse planes are rarely found during this task in subjects with mild-to-moderate symptoms. Turning movements are frequently encountered during everyday life and might require larger hip mobility compared to straight walking, especially in the frontal and transverse planes. Thus, hip mobility and hip loading during straight walking and 90° turns in persons with HOA and healthy older adults were compared in this study. Methods: A retrospective analysis was conducted on 21 subjects with mild-to-moderate HOA and 21 healthy controls. Hip angles and moments were assessed during straight walking and 90° step and spin turns. Gait analysis was conducted using a motion capture system and a force plate. Group and movement task differences were assessed with a mixed-model ANOVA. Results: Peak abduction and adduction angles were largest during the step and spin turn, respectively, as were the group differences between HOA subjects and healthy subjects. Both turns require a greater transverse hip range of motion compared to straight walking. Limitations in transverse hip mobility in the HOA group were especially prominent during the step turn. Both turns cause higher joint moments than straight walking. Conclusions: The additional inclusion of 90° step and spin turns into gait analysis can enhance early identification of hip mobility limitations in the frontal and transverse planes in subjects with mild-to-moderate hip osteoarthritis. Early diagnosis is crucial for the timely application of conservative treatment strategies.

Patients with Hip Osteoarthritis Have a Higher Rate of Spinal Reoperation Following Lumbar Spinal Fusion.

Lumbar spinal pathology is known to affect outcomes following total hip arthroplasty (THA). However, the effect of hip osteoarthritis (OA) on outcomes following lumbar fusion has not been well studied. The purpose of this study was to determine the association between hip OA and spinal reoperation following lumbar spinal fusion. The 5% Medicare Part B claims database was queried for all patients who underwent primary elective lumbar fusion from 2005 to 2019. Patients were divided into 2 groups: those who underwent elective THA within 1 year after primary lumbar fusion, indicating that they had severe hip OA at the time of lumbar fusion, and those who underwent lumbar fusion with no diagnosed hip OA and no THA during the study period. Exclusion criteria included THA as a result of trauma, revision THA or primary THA in the 5-year period before primary lumbar fusion, <65 years of age, and no enrollment in the database for 5 years before and 1 year after primary lumbar fusion. The primary outcome was spinal reoperation within 1, 3, and 5 years. Multivariable Cox regression was performed with age, sex, diabetes, heart disease, obesity, smoking status, osteoporosis, number of levels fused, use of posterior instrumentation, use of an interbody device, use of bone graft, and surgical approach as covariates. Overall, 1,123 patients (63.4% female; 91.3% White; mean age, 76.8 ± 4.1 years) were included in the hip OA group and 8,893 patients (56.2% female; 91.3% White; mean age, 74.8 ± 4.9 years) were included in the control group. After multivariable analysis, patients with severe hip OA had significantly greater rates of revision surgery at 3 years (odds ratio [OR], 1.61; p < 0.001) and 5 years (OR, 1.87; p < 0.001) after the index lumbar fusion. Patients with severe hip OA at the time of primary lumbar fusion had a significantly increased risk of spinal reoperation at 3 and 5 years postoperatively. These data provide further evidence to support performing THA prior to lumbar fusion in the unsettled debate regarding which surgery should be prioritized for patients with simultaneous degenerative diseases of the hip and lumbar spine. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Analysing Pre-Operative Gait Patterns Using Inertial Wearable Sensors: An Observational Study of Participants Undergoing Total Hip and Knee Replacement

Background. Knee and hip arthroplasty are two of the most frequently performed procedures in orthopaedic surgery. They are associated with positive patient-reported outcomes and significant improvements in quality of life for patients. Despite this, there may be room for further progress by quantifying functional improvements with gait analysis. Our study therefore aims to characterise the disease-specific gait pattern of participants with knee and hip osteoarthritis undergoing total joint replacement using a single chest-based wearable sensor. Methods. Twenty-nine participants awaiting total hip replacement and 28 participants awaiting total knee replacement underwent three-dimensional motion analysis with inertial wearable sensors. These gait metrics were then compared with 28 healthy controls of similar ages. Differences in gait metrics were evaluated using a T-test. The participants were recruited through a single centre to participate in this cross-sectional observational study. Participants with osteoarthritis severity sufficient to warrant surgical intervention were considered for inclusion in our study. The participants were instructed to walk 15–120 m in a hospital environment while fitted with a chest-based wearable sensor. Results. In total, three domains were evaluated, including spatiotemporal, variability and asymmetry parameters. There were marked variations in the gait asymmetry parameters and step length variation in both the hip and knee osteoarthritis patients compared with the healthy controls. The magnitude of gait deterioration in terms of step length asymmetry was greater on average in the hip osteoarthritis group than the knee group. The hip osteoarthritis (+180%, p &lt; 0.001) and knee osteoarthritis (+129%, p = 0.001) groups demonstrated marked differences in step length asymmetry. Discussion. A single chest-based sensor was found to be capable of detecting pathological gait signatures in osteoarthritis patients when compared with age-matched controls. Future studies should compare pre- and postoperative changes to disease-specific gait impairments to validate the use of wearable sensors as a clinical adjunct.

Risk factors for hip osteoarthritis after arthroscopy in patients with femoroacetabular impingement

To investigate the risk factors of hip osteoarthritis（HOA） after hip arthroscopy in patients with femoro-acetabular impingement（FAI） syndrome, and to reduce and prevent HOA. From September 2018 to September 2020, 106 patients with FAI underwent hip arthroscopy, including 40 males and 66 females, aged from 20 to 55 years old with an average age of （33.05±10.19） years old. The mechanism of injury included 51 cases for sports injury, 36 for traffic accidents, and 19 for blunt object injury. The duration of the disease ranged from 5 to 19 days with an average of （12.02±3.69） days. All patients were followed up for 18 months. Patients were divided into HOA group （23 cases） and non-HOA group （83 cases） according to the occurrence of HOA. Multivariate Logistic regression was used to analyze the risk factors of HOA after hip arthroscopy in FAI patients. By univariate analysis, aged from 50 to 70 years old, female, body mass index（BMI）> 30 kg·m-2, physical labor, cam type, postoperative infection, last follow-up hip degree of motion （range of motion, ROM） （flexion, abduction, adduction, internal rotation） and Tönnis grade 1 and above of the HOA group were higher than those of the non-HOA group （P<0.05）, and the relative appendicular skeletal muscle index （RASM） was lower than that of non-HOA group（P<0.05）. By multiple Logistic regression analysis, cam type, BMI>30 kg·m-2, last follow-up hip internal rotation ROM and Tönnis grade 1 were risk factors for HOA after hip arthroscopy in FAI patients （P<0.05）. FAI classification, body mass index, hip ROM and Tönnis grade are all related to HOA after hip arthroscopy in FAI patients. Follow-up and intervention should be strengthened in high-risk FAI patients to reduce the occurrence of HOA.

Digital musculoskeletal program is associated with decreased joint replacement rates.

To compare 12-month total knee arthroplasty (TKA) and total hip arthroplasty (THA) rates for digital musculoskeletal (MSK) program members vs patients who received traditional care for knee or hip osteoarthritis (OA). Retrospective, longitudinal study with propensity score-matched comparison group that used commercial medical claims data representing more than 100million commercially insured lives. Study participants with hip OA (M16.x) or knee OA (M17.x) International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) codes were identified in the medical claims database. Digital MSK program members were identified using record linkage tokens. The comparison group had hip- or knee-related physical therapy identified via ICD-10-CM and Current Procedural Terminology codes. Respectively in each knee and hip OA group, digital members were matched to control group patients with similar demographics, comorbidities, and baseline MSK-related medical care use. TKA and THA at 12 months post participation were compared. In the knee OA group, 739 of 56,634 control group patients were matched to 739 digital members. At 12months, 3.79% of digital members and 14.21% of control group patients had TKA (difference, 10.42%; P < .001). In the hip OA group, 141 of 20,819 control group patients were matched to 141 digital members. At 12 months, 16.31% of digital members and 32.62% of control group patients had THA (difference, 16.31%; P = .001). These findings suggest that patients who participated in a digital MSK program to manage OA have lower rates of total joint arthroplasty in the 12 months afterenrollment.

Stabilization and compensation strategy of the hip angle during gait in hip-osteoarthritis patients from the perspective of whole-body movement synergy

BackgroundThe implementation of a strategy to control the hip angle during gait is important to avoid disease progression in patients with hip osteoarthritis (OA). Research questionDo patients with hip OA tend to stabilize their hip angles by a combination of whole-body movements during gait in terms of variability? MethodsA public gait dataset comprising 80 asymptomatic participants and 106 patients with hip OA was used. Uncontrolled manifold analysis was performed using the joint angles as elemental variables and the hip joint angles as performance variables. The synergy index ΔV, variances of elemental variables that did not affect the performance variable (VUCM) and of those that affected the performance variable (VORT), and index of covariation strategy (COV) were calculated in sagittal and frontal plane. A one-sample t-test for statistical parametric mapping (SPM) analysis was used for ΔV and COV. Two-sample t-tests of SPM analyses were used for ΔV, VUCM, and VORT to compare the two groups. ResultsIn both planes, the ΔV and COV were significantly larger than zero in both groups (p < 0.001). In the sagittal plane, the VORT was higher in the hip OA group than in the control group after 77 % of stance phase. In the frontal plane, the hip OA group had larger ΔV and VUCM after last half and last quartile of stance phase compared to the control group, respectively. The VORT was smaller in the hip OA group than in the control group. SignificanceThe hip angle was stabilized in the hip OA group in the frontal plane but insufficiently stabilized in the sagittal plane; however, the patients changed their hip angle during the early phase of stance. The combination of whole-body movements contributed to the stabilization of hip angle.

Individual muscle contributions to the acceleration of the centre of mass during gait in people with mild-to-moderate hip osteoarthritis

BackgroundPeople with mild-to-moderate hip osteoarthritis (OA) exhibit hip muscle weakness, alterations in hip kinematics and kinetics and hip contact forces during gait compared to healthy controls. However, it is unclear if those with hip OA use different motor control strategies to coordinate the motion of the centre of mass (COM) during gait. Such information could provide further critical assessment of conservative management strategies implemented for people with hip OA. Research questionDo muscle contributions to the acceleration of the COM during walking differ between individuals with mild-to-moderate hip OA and controls? MethodsEleven individuals with mild-to-moderate hip OA and 10 healthy controls walked at a self-selected speed while whole-body motion and ground reaction forces were measured. Muscle forces during gait were obtained using static optimisation and an induced acceleration analysis was performed to determine individual muscle contributions to the acceleration of the COM during single-leg stance (SLS). Between-group comparisons were made using independent t-tests via Statistical Parametric Modelling. ResultsThere were no between-group differences in spatial-temporal gait parameters or three-dimensional whole-body COM acceleration. The rectus femoris, biceps femoris, iliopsoas and gastrocnemius muscles in the hip OA group contributed less to the fore-aft accelerations of the COM (p < 0.05), and more to the vertical COM acceleration with the gluteus maximus (p < 0.05), during SLS, compared to the control group. SignificanceSubtle differences exist in the way people with mild-to-moderate hip OA use their muscles to accelerate the whole-body centre of mass during the SLS phase of walking relative to healthy controls. These findings improve understanding of the complex functional consequences of hip OA and enhance our understanding of how to monitor the effectiveness of an intervention on biomechanical changes in gait in people with hip OA.

Do individuals with knee osteoarthritis walk with distinct knee biomechanics and muscle activation characteristics? An investigation of knee osteoarthritis, hip osteoarthritis, and asymptomatic groups

BackgroundBiomechanical markers including reductions in sagittal plane kinematics and moments, increases in knee adduction moments (KAM), and altered muscle activations have been identified as hallmark indicators of knee osteoarthritis (OA). However, it remains unknown whether these features of knee OA gait are exclusive to the diseased joint. Research questionTo determine whether specific gait outcomes previously linked to symptomatic medial compartment knee OA are unique to knee OA by concurrently investigating a group of asymptomatic individuals and those with hip OA. Methods16 individuals with moderate medial compartment knee OA, 16 individuals with moderate hip OA, and 16 asymptomatic controls were recruited. Participants walked on a treadmill while segment kinematics and ground reaction forces were recorded. Sagittal plane kinematics and sagittal and frontal plane moments were calculated. Surface electromyograms were recorded from lateral and medial hamstrings and gastrocnemius and vastus lateralis and medialis. Discrete variable analysis was used to investigate knee joint mechanics and muscle activation ratios. Analysis of Variance models using Bonferroni corrections determined between group differences (α = 0.0167). ResultsSagittal plane knee kinematics and moments were statistically similar among all groups (p > 0.0167). No differences were found for peak KAM and impulse between knee OA and asymptomatic groups (p > 0.0167) but peak KAM (p = 0.006 and impulse (p = 0.001) were greater in the knee OA group compared to hip OA. The hip OA group had a lower KAM impulse (p < 0.0167) compared to the knee OA and asymptomatic groups. A greater LH:MH activation ratio (p < 0.0167) was found in the knee OA group compared to hip OA and asymptomatic groups. No other activation ratio differences were found (p > 0.0167). SignificanceMedial and lateral hamstring muscle activation levels may provide utility as a knee OA gait biomarker compared to biomechanical outcomes, quadriceps and gastrocnemius activation, when differentiating knee OA from asymptomatic and hip OA cohorts.

Are inflammatory parameters an independent predictor of hip osteoarthritis severity? A prospective cross-sectional study.

This study aimed to investigate the relationship between the presence of hip osteoarthritis and the neutrophil-lymphocyte ratio, platelet-lymphocyte ratio, monocyte-lymphocyte ratio, and neutrophil-monocyte ratio. Participants with hip osteoarthritis and healthy controls aged 45-75 years were recruited in the study. The participants with hip osteoarthritis were divided into two groups: mild/moderate hip osteoarthritis and severe hip osteoarthritis. Complete blood parameters of the participants were recorded, and neutrophil-lymphocyte ratio, neutrophil-monocyte ratio, monocyte-lymphocyte ratio, and platelet-lymphocyte ratio were calculated. Pain severity was evaluated using a visual analog scale. A total of 76 participants with hip osteoarthritis and 59 healthy controls were included in the study. The mean age of the participants was 57.6±6.11 years. Mean neutrophil-lymphocyte ratio and neutrophil-monocyte ratio values were statistically significantly different between the hip osteoarthritis group and healthy control group (p<0.05). Platelet-lymphocyte ratio, monocyte-lymphocyte ratio, erythrocyte sedimentation rate, and C-reactive protein values were not significantly different between the groups. Also, there was no difference between all inflammatory parameters and hip osteoarthritis severity (p>0.05). Neutrophil-lymphocyte ratio and neutrophil-monocyte ratio values were higher in patients with hip osteoarthritis than in healthy controls. Mean platelet-lymphocyte ratio, monocyte-lymphocyte ratio, erythrocyte sedimentation rate, and C-reactive protein values did not change according to the presence of hip osteoarthritis. Not all hematological indices give valuable information regarding the severity of hip osteoarthritis.

Association between sagittal spinopelvic alignment and femoral head destruction in the early stage of rapidly destructive coxopathy.

AimsThis study aimed to evaluate sagittal spinopelvic alignment (SSPA) in the early stage of rapidly destructive coxopathy (RDC) compared with hip osteoarthritis (HOA), and to identify risk factors of SSPA for destruction of the femoral head within 12 months after the disease onset.MethodsThis study enrolled 34 RDC patients with joint space narrowing > 2 mm within 12 months after the onset of hip pain and 25 HOA patients showing femoral head destruction. Sharp angle was measured for acetabular coverage evaluation. Femoral head collapse ratio was calculated for assessment of the extent of femoral head collapse by RDC. The following parameters of SSPA were evaluated using the whole spinopelvic radiograph: pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), sagittal vertical axis (SVA), thoracic kyphosis angle (TK), lumbar lordosis angle (LL), and PI-LL.ResultsThe HOA group showed higher Sharp angles compared with the RDC group. PT and PI-LL were higher in the RDC group than the HOA group. SS and LL were lower in the RDC group than the HOA group. No difference was found in PI, SVA, or TK between the groups. Femoral head collapse ratio was associated with PT, SS, SVA, LL, and PI-LL. A PI-LL > 20° and a PT > 30° correlated with greater extent of femoral head destruction by RDC. From regression analysis, SS and SVA were significantly associated with the femoral head collapse ratio within 12 months after disease onset.ConclusionCompared with HOA, RDC in the early stage correlated with sagittal spinopelvic malalignment. SS and SVA may partially contribute to the extent of femoral head destruction by RDC within 12 months after the onset of hip pain. The present study indicates a potential role of SSPA assessment in identification of RDC patients at risk for subsequent bone destruction.Cite this article: Bone Jt Open 2022;3(1):77–84.

Hip Sway in Patients With Hip Osteoarthritis During One-Leg Standing With a Focus on Time Series Data.

This study aimed to investigate the hip sway and the relationship between the center of pressure (CoP) and kinematic parameters regarding the time series scaling component α in patients with hip osteoarthritis (OA) during a one-leg standing task. The scaling exponent α, SD, hip sway maximal acceleration change, and balance performance, which was measured using CoP parameters, were compared between hip OA and control groups during a one-leg standing task. The relationships between balance performance with CoP parameters and kinematic parameters were investigated with the regression analysis. In the hip OA group, the scaling exponent α was smaller in the medial-lateral direction, and the SD and maximal amount of change in hip sway acceleration were larger in the anterior-posterior direction in the hip OA group. In this group, the CoP parameters were significantly associated with α in the medial-lateral direction (negatively) and in the anterior-posterior direction (positively). In the hip OA group, hip sway adaptability in the medial-lateral direction was limited, while the anterior-posterior direction showed greater movement.

Effects of unweighting on gait kinematics during walking on a lower-body positive-pressure treadmill in patients with hip osteoarthritis

BackgroundHip osteoarthritis (OA) is a musculoskeletal condition that makes walking difficult due to pain induced by weight-bearing activities. Treadmills that support the body weight (BW) reduce the load on the lower limbs, and those equipped with a lower-body positive-pressure (LBPP) device, developed as a new method for unweighting, significantly reduce pain in patients with knee OA. However, the effects of unweighting on gait kinematics remain unclear in patients with hip OA. Therefore, we investigated the effects of unweighting on kinematics in patients with hip OA during walking on a treadmill equipped with an LBPP device.MethodsA total of 15 women with hip OA and 15 age-matched female controls wore a three-dimensional (3-D) motion analysis system and walked at a self-selected speed on the LBPP treadmill. Data regarding self-reported hip pain using a numeric rating scale (NRS) in which the scores 0 and 10 represented no pain and the worst pain, respectively, under three different BW conditions (100, 75, and 50%) were collected. Moreover, 3-D peak joint angles during gait under each condition were calculated and compared.ResultsIn the hip OA group, the NRS pain scores at 50 and 75% BW conditions significantly decreased compared with that at 100% BW condition (50%, P = 0.002; 75%, P = 0.026), and the peak hip extension angle decreased compared with that in the healthy controls (P = 0.044). In both groups, unweighting significantly decreased the peak hip (P < 0.001) and knee (P < 0.001) flexion angles and increased the peak ankle plantar flexion angle (P < 0.001) during walking.ConclusionsUnweighting by the LBPP treadmill decreased pain in the hip OA group but did not drastically alter the gait kinematics compared with that in the control group. Therefore, regarding the use of the LBPP treadmill for patients with hip OA, clinicians should consider the benefits of pain reduction rather than the kinematic changes.

Complexity of Gait Angle Measurements at the Ankle Joint During Midstance in Patients with Osteoarthritis.

The evolution of rehabilitation treatments can be quantified through goniometric measurements. Thus, a video goniometer, and an app-based goniometry program can be both useful and a reliable method of obtaining a data base through which we can see if a certain rehabilitation treatment works out for our patients and during times such as the Covid-19 pandemic, a telemedicine approach can be done. Midstance is a sub-moment of the gait pattern, important in the stability of the lower limb, but that can also direct us towards a patient prone to falls. Osteoarthritis is a disease that causes high disability because of the cellular degradation that also affects normal gait. Four groups of subjects: subjects suffering from hip osteoarthritis, knee osteoarthritis, hip and knee osteoarthritis and control group, have been filmed and recorded their midstance joint range of motion in the Angles App. The dominant limb has been proven to have a more extended ankle in the hip osteoarthritis group, compared to knee osteoarthritis, hip and knee osteoarthritis or control group. Females have presented a more extended ankle, wearing high heels for a long period of time can be the cause of that. Subjects with knee osteoarthritis have presented a more flexed ankle in the dominant limb compared to the ones suffering from hip and knee osteoarthritis or control group. The ankle joint can also have its range of motion measured with a video goniometer, helping us compare results in between sessions of rehabilitation in osteoarthritic patients.

Degeneration of the Sacroiliac Joint in Hip Osteoarthritis Patients: A Three-Dimensional Image Analysis.

Objective:The sacroiliac joint is an important source of low back pain and may be influenced by pathologies in adjoining structures such as the hip or the spine. This study aimed to investigate the influence of hip osteoarthritis on sacroiliac joint degeneration by examining the sacroiliac joints of hip osteoarthritis patients, focusing on the localization and quantity of vacuum phenomena.Materials and Methods:The preoperative computed tomography (CT) of 31 female hip replacement candidates (mean age 69.1) and pelvic CT of 34 age-matched controls (mean age 67.9) were used to reconstruct the sacroiliac joints three-dimensionally. The degeneration score of the sacroiliac joints on axial view, as well as the location and volume of vacuum phenomena in the three-dimensionally reconstructed sacroiliac joints, were analyzed.Results:The total sacroiliac joint degeneration scores were similar in hip osteoarthritis patients and controls but the breakdown of the score revealed that joint space narrowing and vacuum phenomena in the sacroiliac joint increase in hip osteoarthritis, while osteophytes decrease. Three-dimensional reconstruction revealed that the volume of vacuum phenomena in the sacroiliac joint was significantly larger in the hip osteoarthritis group and the vacuum areas were localized in the antero-superior region of the sacroiliac joint.Conclusion:Our results suggest that hip osteoarthritis and sacroiliac joint degeneration are related, and that with further investigation, the sacroiliac joint may become a new treatment target in hip osteoarthritis.

Individuals with mild-to-moderate hip osteoarthritis exhibit altered pelvis and hip kinematics during sit-to-stand

BackgroundPerformance of the sit-to-stand (STS) task is compromised in individuals with advanced hip osteoarthritis (OA). Understanding how STS performance is altered in individuals with mild-to-moderate hip OA may inform interventions to improve function and slow disease progression. Research questionDo trunk, pelvis, and hip biomechanics differ during a STS task between individuals with mild-to-moderate hip OA and a healthy, age-matched control group? MethodsThirteen individuals with mild-to-moderate symptomatic and radiographic hip OA and seventeen healthy, age-matched controls performed a standardized STS task. Data were acquired using a three-dimensional motion capture system. The primary outcome measures were task duration, sagittal and frontal plane trunk, pelvis, and hip joint angles, and sagittal and frontal plane trunk and hip joint moments. Comparisons of lower-limb measures were between the most affected side in the hip OA group and a randomly chosen limb for the control group, termed the index limb, prior to and following lift-off from the chair. ResultsParticipants with mild-to-moderate hip OA took longer to perform the STS task compared to controls. Prior to lift-off, the hip OA group exhibited greater posterior pelvic tilt, greater pelvic rise on the index side and less hip joint flexion relative to controls. Following lift-off, the hip OA group exhibited greater pelvic rise on the index side compared to controls. SignificanceIndividuals with mild-to-moderate hip OA exhibit subtle alterations in movement strategy compared to healthy controls when completing a STS task similar, to a small extent, to adaptations reported in advanced stages of the disease. Interventions to target these features and prevent further decline in physical function may be warranted in the management of mild-to-moderate hip OA while the opportunity remains.

Individuals with mild-to-moderate hip osteoarthritis walk with lower hip joint contact forces despite higher levels of muscle co-contraction compared to healthy controls

Purpose: Conservative non-pharmacological interventions are recommended for the clinical management of hip osteoarthritis (OA), though no existing treatments can modify structural disease progression. Evidence-based treatment targets are required to inform the development of disease-course altering interventions. Abnormal hip joint loading is potentially modifiable (e.g. gait and/or neuromuscular retraining) and may play an important role in hip OA progression. No previous study has investigated whether individuals with mild-to-moderate hip OA exhibit altered hip joint contact forces (HJCF) during gait, or identified any relevant contribution of altered hip muscle co-contraction to hip joint loading in this patient population. This study aimed to compare: (1) HJCF between individuals with mild-to-moderate hip OA and healthy controls during walking using an electromyography (EMG)-informed modelling approach; and (2) hip muscle co-contraction levels between groups. Methods: Eighteen participants (age=65±7 yrs; body mass index=27.6±4.8 kg.m-2; 72% females) with mild-to-moderate hip OA and 23 healthy controls without hip pain or radiographic hip OA (age=60±8 yrs; body mass index=25.1±4.8 kg.m-2; 74% females) performed 10 over-ground walking trials at a self-selected speed. Three-dimensional lower-body motion, ground reaction forces, and surface EMG from sixteen lower-limb muscles were synchronously acquired.Hip joint contact forces were solvedby balancing the external joint moments with internal muscle forces estimated using a calibrated EMG-informed neuromusculoskeletal model. Hip muscle contributions and co-contraction ratios (abduction/adduction and flexion/extension) were determined. Demographic, spatiotemporal, and primary outcome measures were compared between groups using independent t-tests. A secondary analysis of HJCF peaks was performed usingaone-way analysis of covariance with body mass index as a covariate (p<0.05). Results: Height, body mass, body mass index, and walking speed did not differ between groups. Participants with hip OA walked with an 11% lower first peak (p=0.01) and 28% lower second peak (p<0.01) HJCF compared to controls (Fig. 1). Differences remained significant when adjusted for body mass index. Participants in the hip OA group exhibited higher levels of hip muscle co-contraction in both flexion/extension (p<0.01) and abduction/adduction (p=0.04) during all phases of stance compared to controls. Hip muscle forces (p<0.01), peakhip extension (p<0.01) and peak hip adduction (p=0.03) joint angles, and peak hip flexion (p=0.01) and peak hip extension (p<0.01) joint moments were also lower in the hip OA compared to control group. Conclusions: Individuals with mild-to-moderate hip OA walk with lower HJCF, despite exhibiting higher levels of hip muscle co-contraction, compared to healthy controls. These observations contradict previous assumptions regarding the effect of higher levels of muscle co-contraction on joint loading in this cohort.This is the first study to demonstrate that under-loading is characteristic of individuals with early hip OA, and may suggest that interventions aimed at reducing hip joint loading are not appropriate for this patient group. Future studies are required to evaluate the effects of under-loading on hip cartilage health, with the aim of identifying modifiable treatment targets to slow disease progression in individuals with hip OA.

Preoperative dual-energy X-ray absorptiometry and FRAX in patients with lumbar spinal stenosis

BackgroundOsteoporosis implies an increased risk of complications after orthopedic surgery. For the mostly elderly group of patients undergoing lumbar spinal stenosis surgery (LSS), it is important to include skeletal health evaluation in the preoperative planning. The aim of this study was to assess spine and femoral neck (FN) bone mineral density (BMD) in LSS patients and to evaluate whether the World Health Organization (WHO) fracture risk assessment tool (FRAX) can identify patients with reduced BMD levels in the spine.MethodsThe study involved 65 LSS patients and 53 patients with hip osteoarthritis (HOA) for comparison. BMD was measured with dual-energy X-ray absorptiometry (DXA) in the lumbar spine in three projections: anterior-posterior (AP), lateral and lateral-mid (the mid-portion of the vertebrae), and FN. The LSS patients filled out the FRAX questionnaire.ResultsIn the LSS group, 43% of the women and 8% of the men were classified as being osteoporotic/osteopenic by AP spine measurement. The corresponding proportions using the lateral spine T-score ≤ − 2.5 were 87% and 57%, respectively, and 82% and 53%, respectively, for the FN. The FN BMD T-score was significantly lower in the LSS group compared with the HOA group. The FRAX questionnaire identified 40% of the LSS patients with a moderate/high risk of sustaining an osteoporotic fracture within 10 years, with or without simultaneous FN BMD, while 71% of these patients were classified as being osteoporotic with DXA lateral spine measurement.ConclusionIt is common with osteoporosis/osteopenia in patients undergoing spine surgery, and the identification may influence the surgical treatment why the evaluation of BMD is important preoperatively. FRAX evaluation could not replace DXA measurement of the spine regarding the identification of osteoporosis patients in the preoperative planning phase.

Individuals with mild-to-moderate hip osteoarthritis have lower limb muscle strength and volume deficits

BackgroundIndividuals with advanced hip osteoarthritis (OA) exhibit generalized muscle weakness of the affected limb and so clinical practice guidelines recommend strength training for the management of hip OA. However, the extent and pattern of muscle weakness, including any between-limb asymmetries, in early stages of the disease are unclear. This study compared hip and knee muscle strength and volumes between individuals with mild-to-moderate symptomatic and radiographic hip OA and a healthy control group.MethodsNineteen individuals with mild-to-moderate symptomatic and radiographic hip OA (n = 12 unilateral; n = 7 bilateral) and 23 age-matched, healthy controls without radiographic hip OA or hip pain participated. Isometric strength of the hip and knee flexors and extensors, and hip abductors and adductors were measured. Hip and thigh muscle volumes were measured from lower limb magnetic resonance images. A full-factorial, two-way General Linear Model was used to assess differences between groups and between limbs.ResultsParticipants in the hip OA group demonstrated significantly lower knee flexor, knee extensor, hip flexor, hip extensor and hip abductor strength compared to controls and had significantly lower volume of the adductor, hamstring and quadriceps groups, and gluteus maximus and gluteus minimus muscles, but not tensor fasciae latae or gluteus medius muscles. There were no between-limb strength differences or volume differences within either group.ConclusionsAtrophic, bilateral hip and knee muscle weakness is a feature of individuals with mild-to-moderate hip OA. Early interventions to target muscle weakness and prevent the development of strength asymmetries that are characteristic of advanced hip OA appear warranted.

Intersegmental kinematics coordination in unilateral peripheral and central origin: Effect on gait mechanism?

BackgroundThe gait mechanism requires an efficient intersegmental coordination in order to ensure the displacement of the body while simultaneously maintaining the postural stability. However, intersegmental coordination may be disrupted by neurological or orthopaedic involvement, this increasing the metabolic cost associated with excessive or prolonged muscle co-contraction. Research questionOur aim was to evaluate and to understand how hip OA affects lower limbs coordination during gait by using the kinematic segmental covariation law method and predict the energy expenditure. MethodsIn order to evaluate the influence of unilateral alteration of the lower limbs on the gait mechanism, three groups namely 63 hip osteoarthritis patients, 65 chronic hemiparetic stroke patients and 72 healthy subjects performed an instrumented gait analysis. The subjects had to walk barefoot for at least 3 min at a self-selected speed on a force measuring motor-driven treadmill. The biomechanical variables (kinematic, kinetic and energetical cost) were simultaneously recorded. ResultsThe comparison between the three groups was tested using a repeated measure ANOVA. All biomechanical parameters show significant differences between the 3 groups highlighting the gait alteration for the patients groups. However, the energetic cost remains normal in the hip osteoarthritis group despite of the alteration of the other variables. A multivariate analysis allowed to identify the independent variables affecting more specifically their gait mechanisms. SignificanceThis study showed the importance of quantitative functional evaluation in order to better understand the impact of hip osteoarthritis on the gait mechanism. The biomechanical analysis provides objective evidence of the altered gait mechanism and more particularly of the intersegmental coordination in these patients. This gait analysis is therefore an interesting tool in the functional evaluation of the patient to better guide the diagnosis.

Sagittal spino-pelvic alignment in rapidly destructive coxarthrosis.

To investigate the sagittal spino-pelvic alignment (SSPA) in patients with rapidly destructive coxarthrosis (RDC). SSPA was investigated in 44 patients with RDC and 70 patients with hip osteoarthritis (HOA). The study included only female patients over the age of 70years because epidemiological reports indicate that RDC most commonly occurs in this group of patients. The SSPA parameters that were analyzed included lumbar lordosis (LL), lumbar range of motion (ΔLL), sacral slope (SS), pelvic incidence (PI), and pelvic tilt (PT). The pelvic inclination angle (PIA) in the supine position and the change in the PIA from the supine to the standing position (ΔPIA) were measured using anteroposterior pelvic radiographs. The values of these parameters were compared between the two groups. The levels of the SRS-Schwab classification modifiers were used to investigate the degree of sagittal malalignment. The RDC group showed significant lower LL, ΔLL and SS values, and significantly higher PT and ΔPIA values than the HOA group (P<0.01). With regard to the sagittal modifiers in the SRS-Schwab classifications of the patients, the PI-LL and PT levels of the RDC group were significantly worse than those in the HOA group (P<0.01). The present study suggests that the static factors of a reduction in the lumbar lordotic angle and greater posterior pelvic tilt, the dynamic factors of small ΔLL values and large ΔPIA values and the complex interaction of these two types of factors, may play important roles in the development of RDC.