Femoroacetabular impingement alters hip and pelvic biomechanics during gait: Walking biomechanics of FAI

Femoroacetabular impingement (FAI) has been reported to cause hip pain in a variety of daily activities including walking. However, the biomechanics of level gait has not been compared between FAI patients and a control group. This study quantified the affect of cam FAI on the three-dimensional (3-D) kinematics of the hip and pelvis, as well as the 3-D kinetics generated at the hip during walking. A unilateral cam impingement group (n = 17) was compared to a matched control group (n = 14) using between-group one-way ANOVAs. The FAI group had significantly lower peak hip abduction (p = 0.009), frontal range of motion (ROM) (p = 0.003), as well as attenuated pelvic frontal ROM (pelvic roll) (p = 0.004) compared to the controls during level gait. There was also a trend of the impinged group having a lower sagittal ROM (p = 0.047) than the controls. However, there were no kinetic differences between the two groups. Attenuated hip abduction, frontal ROM and sagittal ROM during gait in FAI individuals may be caused by soft tissue restriction, and decreased frontal pelvic ROM could result from limited mobility at the sacro-lumbar joint.     

Relationships among spinal mobility and sagittal alignment of spine and lower extremity to quality of life and risk of falls

Spinal deformities can affect quality of life (QOL) and risk of falling, but no studies have explored the relationships of spinal mobility and sagittal alignment of spine and the lower extremities simultaneously. Purpose of this study is to clarify the relationship of those postural parameters to QOL and risk of falling. The study evaluated 110 subjects (41 men, 69 women; mean age, 73 years). Upright and flexion and extension angles for thoracic kyphosis, lumbar lordosis, and spinal inclination were evaluated with SpinalMouse^®. Total-body inclination and hip and knee flexion angles in upright position were measured from lateral photographs. Subjects were divided into Fallers (n = 23, 21%) and Non-fallers (n = 87, 79%) based on past history of falls. QOL was assessed using the Short Form 36 Health Survey (SF-36^®). Age, total-body inclination, spinal inclination upright and in extension, thoracic kyphosis in flexion, lumbar lordosis upright and in extension, and knee flexion correlated significantly with the SF-36. Multiple regression analysis revealed total-body inclination and knee flexion to have the most significant relationships with the SF-36. SF-36, total-body inclination, spinal inclination in extension, thoracic kyphosis in flexion, lumbar lordosis upright and in extension, and hip and knee flexion angles differed significantly between Fallers and Non-fallers (P < 0.05 for all). Multivariate logistic regression analyses revealed lumbar lordosis in extension to be a significant predictor of falling (P = 0.038). Forward-stooped posture and knee-flexion deformity could be important indicator of lower QOL. Moreover, limited extension in the lumbar spine could be a useful screening examination for fall prevention in the elderly.     

Effects of high-heeled footwear on static and dynamic pelvis position and lumbar lordosis in experienced younger and middle-aged women

There is still conflicting evidence about the effect of high-heeled footwear on posture, especially if methodological confounders are taken into account. The purpose of this study was to investigate the effect of high-heeled footwear on lumbopelvic parameters in experienced younger and middle-aged women while standing and walking. Thirty-seven experienced younger (n = 19:18–25 years) and middle-aged (n = 18:26–56 years) women were included in this randomized crossover study. Using a non-invasive back shape reconstruction device (rasterstereography), static (pelvic tilt and lumbar lordosis angle) and dynamic (pelvic rotation, median lumbar lordosis angle and range of motion) parameters representing pelvis position and lumbar curvature were measured. In order to analyse standing and walking on a treadmill (0.83 m/s), the effects of high-heels (7–11 cm) were compared to standard control shoes. There were no effects on the lumbar lordosis angle or range of motion under static or dynamic conditions (p > 0.05, d ≤ 0.06). But there was a small effect for a reduced pelvic tilt (p = 0.003, d = 0.24) and a moderate effect for an increased transversal pelvic rotation (p = 0.001, d = 0.63) due to high heel shoed standing or walking, respectively. There were no significant age-group or interaction effects (p > 0.05).Altered pelvic parameters may be interpreted as compensatory adaptations to high-heeled footwear rather than lumbar lordosis adaptations in experienced wearers. The impact of these findings on back complaints should be revisited carefully, because muscular overuse as well as postural load relieving may contribute to chronic consequences. Further research is necessary to examine clinically relevant outcomes corresponding to postural alterations.     

Leg length and offset differences above 5 mm after total hip arthroplasty are associated with altered gait kinematics

We aimed to investigate the relationship between postoperative leg length/offset (LL/OS) reconstruction and gait performance after total hip arthroplasty (THA). In the course of a prospective randomized controlled trial, 60 patients with unilateral hip arthrosis received cementless THA through a minimally-invasive anterolateral surgical approach. One year post-operatively, LL and global OS restoration were analyzed and compared to the contralateral hip on AP pelvic radiographs. The combined postoperative limb length/OS reconstruction of the operated hip was categorized as restored (within 5 mm) or non-restored (more than 5 mm reduction or more than 5 mm increment). The acetabular component inclination, anteversion and femoral component anteversion were evaluated using CT scans of the pelvis and the femur. 3D gait analysis of the lower extremity and patient related outcome measures (HHS, HOOS, EQ-5D) were obtained pre-operatively, six months and twelve months post-operatively by an observer blinded to radiographic results. Component position of cup and stem was comparable between the restored and non-restored group. Combined LL and OS restoration within 5 mm resulted in higher Froude number (p < 0.001), normalized walking speed (p < 0.001) and hip range-of-motion (ROM) (p = 0.004) during gait twelve months postoperatively, whereas gait symmetry was comparable regardless of LL and OS reconstruction at both examinations. Clinical scores did not show any relevant association between the accuracy of LL or OS reconstruction and gait six/twelve months after THA. In summary, postoperative LL/OS discrepancies larger than 5 mm relate to unphysiological gait kinematics within the first year after THA. DRKS00000739, German Clinical Trials Register.     

Roussouly’s sagittal spino-pelvic morphotypes as determinants of gait in asymptomatic adult subjects

Sagittal alignment is known to greatly vary between asymptomatic adult subjects; however, there are no studies on the possible effect of these differences on gait. The aim of this study is to investigate whether asymptomatic adults with different Roussouly sagittal alignment morphotypes walk differently. Ninety-one asymptomatic young adults (46 M & 45 W), aged 21.6 ± 2.2 years underwent 3D gait analysis and full body biplanar X-rays with three-dimensional (3D) reconstructions of their spines and pelvises and generation of sagittal alignment parameters. Subjects were divided according to Roussouly’s sagittal alignment classification. Sagittal alignment and kinematic parameters were compared between Roussouly types. 17 subjects were classified as type 2, 47 as type 3, 26 as type 4 but only 1 as type 1. Type 2 subjects had significantly more mean pelvic retroversion (less mean pelvic tilt) during gait compared to type 3 and 4 subjects (type 2: 8.2°; type 3:11.2°, type 4: 11.3°) and significantly larger ROM pelvic obliquity compared to type 4 subjects (type 2: 11.0°; type 4: 9.1°). Type 2 subjects also had significantly larger maximal hip extension during stance compared to subjects of types 3 and 4 (type 2: −11.9°; type 3: −8.8°; type 4: −7.9°) and a larger ROM of ankle plantar/dorsiflexion compared to type 4 subjects (type 2: 31.1°; type 4: 27.9°). Subjects with type 2 sagittal alignment were shown to have a gait pattern involving both increased hip extension and pelvic retroversion which could predispose to posterior femoroacetabular impingement and consequently osteoarthritis.     

Does surgical approach or prosthesis type affect hip joint loading one year after surgery?

Several approaches may be used for hip replacement surgery either in combination with conventional total hip arthroplasty (THA) or resurfacing hip arthroplasty (RHA). This study investigates the differences in hip loading during gait one year or more after surgery in three cohorts presenting different surgical procedures, more specific RHA placed using the direct lateral (RHA-DLA, n = 8) and posterolateral (RHA-PLA, n = 14) approach as well as THA placed using the direct anterior (THA-DAA, n = 12) approach. For the DAA and control subjects, hip loading was also evaluated during stair ascent and descent to evaluate whether these motions can better discriminate between patients and controls compared to gait. Musculoskeletal modelling in OpenSim was used to calculate in vivo joint loading. Results showed that for all operated patients, regardless the surgical procedure, hip loading was decreased compared to control subjects, while no differences were found between patient groups. This indicates that THA via DAA results in similar hip loading as a RHA via DLA or PLA. Stair climbing did not result in more distinct differences in hip contact force magnitude between patients and controls, although differences in orientation were more distinct. However, patients after hip surgery did adjust their motion pattern to decrease the magnitude of loading on the hip joint compared to control subjects.     

Single leg stance control in individuals with symptomatic gluteal tendinopathy

BackgroundLateral hip pain during single leg loading, and hip abductor muscle weakness, are associated with gluteal tendinopathy, but it has not been shown how or whether kinematics in single leg stance differ in those with gluteal tendinopathy.PurposeTo compare kinematics in preparation for, and during, single leg stance between individuals with and without gluteal tendinopathy, and the effect of hip abductor muscle strength on kinematics.MethodsTwenty individuals with gluteal tendinopathy and 20 age-matched pain-free controls underwent three-dimensional kinematic analysis of single leg stance and maximum isometric hip abductor strength testing. Maximum values of hip adduction, pelvic obliquity (contralateral pelvis rise/drop), lateral pelvic translation (ipsilateral/contralateral shift) and ipsilateral trunk lean during preparation for leg lift and average values in steady single leg stance, were compared between groups using an analysis of covariance, with and without anthropometric characteristics and strength as covariates.ResultsIndividuals with gluteal tendinopathy demonstrated greater hip adduction (standardized mean difference (SMD) = 0.70, P = 0.04) and ipsilateral pelvic shift (SMD = 1.1, P = 0.002) in preparation for leg lift, and greater hip adduction (SMD = 1.2, P = 0.002) and less contralateral pelvic rise (SMD = 0.86, P = 0.02) in steady single leg stance than controls. When including strength as a covariate, only between-group differences in lateral pelvic shift persisted (SMD = 1.7, P = 0.01).ConclusionIndividuals with gluteal tendinopathy use different frontal plane kinematics of the hip and pelvis during single leg stance than pain-free controls. This finding is not influenced by pelvic dimension or the potentially modifiable factor of body mass index, but is by hip abductor muscle weakness.     

Improvements in spinal alignment after high tibial osteotomy in patients with medial compartment knee osteoarthritis

Since the correlation between spinal and lower extremity alignments is high, high tibial osteotomy (HTO) surgery may also affect spinal alignment, where the spinal alignment parameters are the most important parameters for the evaluation of spinal disorders. In this study, the effect of HTO surgery on spinal alignment during gait was investigated by comparing spinal alignment parameters between patients with knee osteoarthritis (OA) and healthy young controls. Eight patients (age, 55.0 ± 5.1 years; height, 160.3 ± 7.0 cm; weight, 71.3 ± 14.1 kg) with a medial compartment knee OA participated in the gait experiment two times approximately one week before and one year after HTO surgery and eight healthy young controls (age, 26.7 ± 1.7 years; height, 163.4 ± 6.5 cm; weight, 58.4 ± 11.3 kg) participated only once. Cervical curvature angle, thoracic curvature angle, lumbar curvature angle, coronal vertical axis, and coronal pelvic tilt in the coronal plane and cervical lordosis, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, and sagittal pelvic tilt in the sagittal plane were estimated using motion analysis system with skin markers. All spinal alignment parameters after HTO surgery were significantly closer to those of healthy young subjects than those before HTO, especially in the coronal plane. These findings suggest that the HTO had a positive effect on spinal alignment, as well as lower extremity alignment, and moreover, reduced the abnormality that may result in spinal problems such as degeneration or pain.     

The effects of acute experimental hip muscle pain on dynamic single-limb balance performance in healthy middle-aged adults

Middle-aged adults with painful hip conditions show balance impairments that are consistent with an increased risk of falls. Pathological changes at the hip, accompanied by pain, may accelerate pre-existing age-related balance deficits present in midlife. To consider the influence of pain alone, we investigated the effects of acute experimental hip muscle pain on dynamic single-limb balance in middle-aged adults. Thirty-four healthy adults aged 40–60 years formed two groups (Group-1: n = 16; Group-2: n = 18). Participants performed four tasks: Reactive Sideways Stepping (ReactSide); Star Excursion Balance Test (SEBT); Step Test; Single-Limb Squat; before and after an injection of hypertonic saline into the right gluteus medius muscle (Group-1) or ∼5 min rest (Group-2). Balance measures included the range and standard deviation of centre of pressure (CoP) movement in mediolateral and anterior-posterior directions, and CoP total path velocity (ReactSide, Squat); reach distance (SEBT); and number of completed steps (Step Test). Data were assessed using three-way analysis of variance. Motor outcomes were altered during the second repetition of tasks irrespective of exposure to experimental hip muscle pain or rest, with reduced SEBT anterior reach (−1.2 ± 4.1 cm, P = 0.027); greater step number during Step Test (1.5 ± 1.7 steps, P < 0.001); and slower CoP velocity during Single-Limb Squat (−4.9 ± 9.4 mms⁻¹, P = 0.024). Factors other than the presence of pain may play a greater role in balance impairments in middle-aged adults with hip pathologies.     

Spinal sagittal contour affecting falls: Cut-off value of the lumbar spine for falls

Spinal deformities reportedly affect postural instability or falls. To prevent falls in clinical settings, the determination of a cut-off angle of spinal sagittal contour associated with increase risk for falls would be useful for screening for high-risk fallers. The purpose of this study was to calculate the spinal sagittal contour angle associated with increased risk for falls during medical checkups in community dwelling elders. The subjects comprised 213 patients (57 men, 156 women) with a mean age of 70.1 years (range, 55–85 years). The upright and flexion/extension thoracic kyphosis and lumbar lordosis angles, and the spinal inclination were evaluated with SpinalMouse^®. Postural instability was evaluated by stabilometry, using the total track length (LNG), enveloped areas (ENV), and track lengths in the lateral and anteroposterior directions (X LNG and Y LNG, respectively). The back extensor strength (BES) was measured using a strain-gauge dynamometer. The relationships among the parameters were analyzed statistically. Age, lumbar lordosis, spinal inclination, LNG, X LNG, Y LNG, and BES were significantly associated with falls (P < 0.05). Multivariate logistic regression analyses revealed that lumbar lordosis was the most significant factor (P < 0.01). Univariate logistic regression analyses for falls about lumbar lordosis angles revealed that angles of 3° and less were significant for falls. The present findings suggest that increased age, spinal inclination, LNG, X LNG, Y LNG, and decreased BES and lumbar lordosis, are associated with falls. An angle of lumbar lordosis of 3° or less was associated with falls in these community-dwelling elders.     

Effects of distal hamstring lengthening on sagittal motion in patients with diplegia: Hamstring length and its clinical use

This study was undertaken to determine the effect of distal hamstring lengthening (DHL) on hip and knee sagittal kinematics, and to investigate the validity of modeled hamstring length for clinical use. Patient group consisted of 28 patients (56 limbs, mean age 7.4 years) with spastic diplegia who underwent bilateral DHL and tendo-Achilles lengthening with/without rectus femoris transfer (RFT) (DHL + RFT subgroup, 40 limbs; DHL subgroup, 16 limbs). Kinematic data was obtained by gait analysis, and hamstring lengths were obtained using a musculoskeletal modeling technique. Postoperatively, knee extension improved (p < 0.001) without aggravating anterior pelvic tilt (p = 0.565). However, DHL aggravated anterior pelvic tilt in the DHL subgroup (2.2°, p = 0.011). In terms of concurrent validity, hamstring length was found to be correlated with mean pelvic tilt (r = 0.798, p < 0.001) and popliteal angle (r = −0.425, p = 0.001), but the correlation between hamstring length and knee flexion at initial contact was minimal (r = 0.068, p = 0.753). In terms of construct validity, DHL did not lengthen mean hamstring length (p = 0.918). In conclusion, DHL appeared to significantly improve knee motion in patients with spastic diplegia. Furthermore, DHL did not increase pelvic tilt, when performed with RFT. Modeled hamstring length is believed to have limited validity in patients with cerebral palsy, because it does not reflect knee kinematics or postoperative change when DHL was combined with multilevel surgery.     

Posture and balance control in patients with acromegaly: Results of a cross-sectional study

Acromegaly is a chronic debilitating disease that presents with multiple systemic manifestations, including changes in body composition, joint abnormalities, muscular impairment and visual disturbances. This study aimed to assess posture and body balance in acromegalic patients and to establish the correlation between these measures. Twenty-eight acromegalic patients and a similar number of control subjects matched for sex, age, weight, height and body mass index underwent postural evaluation using the photogrammetry and measurement of balance using the stabilometry in two tasks: feet apart, eyes open and feet together, eyes closed. In comparison with the control group, the acromegalic group presented postural deviations in lateral views in the vertical alignment of the trunk (P = 0.001 for the right side and P = 0.021 for the left), the hip angle (P = 0001 for the right side and P = 0.016 for the left side) and horizontal alignment of the pelvis (P = 0.017 for the right and P < 0.001 for the left side). Compared with healthy subjects, the acromegalic patients presented displacement of the centre of pressure in both the anterior–posterior direction and the medial–lateral direction in both evaluated tasks. We observed significant correlations between balance measures and the following posture evaluation variables: distance between the lower limbs, horizontal alignment of the head and vertical alignment of the head. Our results suggest that posture and balance need to be evaluated for acromegalic patients in clinical practice, as there are significant postural imbalances and deviations in these patients.     

Physical functioning four years after total hip and knee arthroplasty

Our previous study showed that 6 months after total hip arthroplasty (THA) or total knee arthroplasty (TKA), patients reported having less difficulty with daily activities, showed better functional capacity, and performed activities in their natural environment faster compared to preoperatively. However, their actual daily activity level was not significantly improved. Six months is a rather short follow-up period and the discrepancy in recovery among different aspects of functioning might be explained by this limited duration of follow-up. The objective of the present study was to examine the recovery of different aspects of physical functioning at a follow-up nearly 4 years after THA/TKA. Special attention was given to the actual daily activity level, and whether it had increased 4 years after THA/TKA compared to 6 months postoperatively.Seventy-seven (35 hip, 42 knee) patients who were measured preoperatively and postoperatively (6 months after surgery) in a previous study were invited to participate; 44 patients (23 hip, 21 knee) agreed to participate. The 4-year follow-up data were compared with the preoperative and 6-month postoperative data.The daily activity level after 4 years was found to be actually lower than at 6 months post-surgery (128 min vs. 138 min activity per 24 h; p-value 0.48). However, the patients continued to improve in other aspects of physical functioning.In conclusion, 4-year post-surgery patients continued to improve on perceived physical functioning, capacity, and performance of activities in daily life. However, even in this relatively healthy study population, patients did not adopt a more active lifestyle 4 years after surgery.     

Footwear characteristics are related to running mechanics in runners with patellofemoral pain

Running footwear is known to influence step rate, foot inclination at foot strike, average vertical loading rate (VLR) and peak patellofemoral joint (PFJ) force. However, the association between the level of minimalism of running shoes and running mechanics, especially with regards to these relevant variables for runners with patellofemoral pain (PFP), has yet to be investigated. The objective of this study was to explore the relationship between the level of minimalism of running shoes and habitual running kinematics and kinetics in runners with PFP. Running shoes of 69 runners with PFP (46 females, 23 males, 30.7 ± 6.4 years) were evaluated using the Minimalist Index (MI). Kinematic and kinetic data were collected during running on an instrumented treadmill. Principal component and correlation analyses were performed between the MI and its subscales and step rate, foot inclination at foot strike, average VLR, peak PFJ force and peak Achilles tendon force. Higher MI scores were moderately correlated with lower foot inclination (r = −0.410, P < 0.001) and lower peak PFJ force (r = −0.412, P < 0.001). Moderate correlations also showed that lower shoe mass is indicative of greater step rate (ρ = 0.531, P < 0.001) and lower peak PFJ force (ρ = −0.481, P < 0.001). Greater shoe flexibility was moderately associated with lower foot inclination (ρ = −0.447, P < 0.001). Results suggest that greater levels of minimalism are associated with lower inclination angle and lower peak PFJ force in runners with PFP. Thus, this population may potentially benefit from changes in running mechanics associated with the use of shoes with a higher level of minimalism.     

Development of gait performance and dynamic hip and knee joint loading after containment improving surgery in patients with Legg–Calvé–Perthes disease

Current surgery outcome evaluations in patients with Legg–Calvé–Perthes disease (LCPD) are usually based on static radiological changes. The aim of the present study was to assess the development of characteristic gait parameters and passive hip range of motion (ROM) measurements during the postoperative period up to healed stage of the femoral head represented by Stulberg classification. Twelve children (10 male, 2 female) with unilateral diagnosis of LCPD and 19 healthy control subjects at the same age participated in this prospective longitudinal study. Instrumented gait analysis was performed preoperatively, 13.4 (±1.7), and 28.0 (±4.4) months postoperatively. At final follow-up, the mean leg length of the involved side was reduced by 1.10 (±0.53) cm compared to the non-involved side. In addition, a significant reduction in maximum knee flexion (−26%, p = 0.037) and knee flexion/extension ROM (−26%, p = 0.017) in stance was still present in the patient group compared to controls indicating a “stiff knee gait pattern”. In contrast, the sagittal plane hip parameters, the ipsilateral trunk lean toward the involved stance limb, and the knee and hip joint loading during gait normalized during the postoperative period. The results of the present study should motivate further exploration if patients with LCPD stiffen their knees to compensate for leg length discrepancy. Besides the standard radiological evaluation of the surgery outcome, instrumented gait analysis is a valuable method of recording functional deficits and early recognition of the need for physiotherapeutic treatment or insole supply in patients with LCPD.     

Shod wear and foot alignment in clinical gait analysis

Sagittal plane alignment of the foot presents challenges when the subject wears shoes during gait analysis. Typically, visual alignment is performed by positioning two markers, the heel and toe markers, aligned with the foot within the shoe. Alternatively, software alignment is possible when the sole of the shoe lies parallel to the ground, and the change in the shoe’s sole thickness is measured and entered as a parameter. The aim of this technical note was to evaluate the accuracy of visual and software foot alignment during shod gait analysis. We calculated the static standing ankle angles of 8 participants (mean age: 8.7 years, SD: 2.9 years) wearing bilateral solid ankle foot orthoses (BSAFOs) with and without shoes using the visual and software alignment methods. All participants were able to stand with flat feet in both static trials and the ankle angles obtained in BSAFOs without shoes was considered the reference. We showed that the current implementation of software alignment introduces a bias towards more ankle dorsiflexion, mean = 3°, SD = 3.4°, p = 0.006, and proposed an adjusted software alignment method. We found no statistical differences using visual alignment and adjusted software alignment between the shoe and shoeless conditions, p = 0.19 for both. Visual alignment or adjusted software alignment are advised to represent foot alignment accurately.     

Effectiveness of an innovative hip energy storage walking orthosis for improving paraplegic walking: A pilot randomized controlled study

BackgroundThe high energy cost of paraplegic walking using a reciprocating gait orthosis (RGO) is attributed to limited hip motion and excessive upper limb loading for support. To address the limitation, we designed the hip energy storage walking orthosis (HESWO) which uses a spring assembly on the pelvic shell to store energy from the movements of the healthy upper limbs and flexion-extension of the lumbar spine and hip and returns this energy to lift the pelvis and lower limb to assist with the swing and stance components of a stride. Our aim was to evaluate gait and energy cost indices for the HESWO compared to the RGO in patients with paraplegia.MethodsThe cross-over design was used in the pilot study. Twelve patients with a complete T4-L5 chronic spinal cord injury underwent gait training using the HESWO and RGO. Gait performance (continuous walking distance, as well as the maximum and comfortable walking speeds) and energy expenditure (at a walking speed of 3.3 m/min on a treadmill) were measured at the end of the 4-week training session.ResultsCompared to the RGO, the HESWO increased continuous walking distance by 24.7% (P < 0.05), maximum walking speed by 20.4% (P < 0.05) and the comfortable walking speed by 15.3% (P < 0.05), as well as decreasing energy expenditure by 13.9% (P < 0.05).ConclusionOur preliminary results provide support for the use of the HESWO as an alternative support for paraplegic walking.     

Vitamin d is related to gait recovery after total hip arthroplasty: A prospective analysis

ObjectivesTo investigate the association between baseline serum levels of 25-hydroxyvitamin D (25(OH)D) and gait pattern in patients undergoing total hip arthroplasty (THA).MethodsProspective study of patients with hip osteoarthritis undergoing primary THA between January 2012 and December 2013. Blood samples were collected on the day of hospital admission. Gait analyses were performed before surgery and 3 months postoperatively. Internal moments were captured.ResultsMajor improvements were observed in gait data after THA. 25(OH)D levels correlated with change in peak extension (R = 0.25, p = 0.017) and peak power generation (R = 0.25, p = 0.04). Multiple linear regression analyses were performed. In model 1, 25(OH)D and change in gait speed explained the variability of peak extension (R2 = 0.1, p = 0.004). In model 2, only 25(OH)D explained the variability of peak power generation (R2 = 0.05, p = 0.044).Conclusions25(OH)D levels were correlated with change in peak extension and peak power generation. The effect of 25(OH)D on change in gait variables after THA is modest.     

Root mean square of lower trunk acceleration during walking in patients with unilateral total hip replacement

Although several studies have described abnormal trunk motion before and after total hip arthroplasty (THA) surgery, few studies have examined trunk motion using accelerometry. The aim of this study was to determine whether abnormal trunk motion persisted after THA using accelerometry.A total of 24 female patients (61.0 ± 6.9 years) and 20 healthy female subjects (59.9 ± 6.8 years) participated in this study. Patients were assessed at 1 month prior to surgery and 12 months after surgery. Trunk acceleration during gait was measured using a triaxial accelerometer attached to the L3 spinous process. We calculated the root mean square (RMS) and RMS ratio (RMSR) in the vertical (VT), medio-lateral (ML), and anterior–posterior (AP) directions.Results revealed that the RMS in the VT and AP directions postoperatively was greater than that preoperatively, whereas there was no difference in the RMS in the ML direction. In addition, the preoperative RMSR in the ML direction was significantly greater compared with that of healthy individuals and the postoperative RMSR. There was no difference in the RMSR in the ML direction between healthy individuals and postoperatively.These findings suggested that the trunk motion in the frontal plane prior to surgery had improved and was comparable to that of healthy individuals following THA.     

Evaluation of the association between osteoporosis and postural balance in postmenopausal women

The incidence of osteoporosis has been increasing, as have fractures resulting from falls. Postural balance was evaluated in postmenopausal women with and without lumbar osteoporosis. One hundred and twenty-six postmenopausal women aged 55–65 years were evaluated and separated into two groups according to the bone mineral density values of their lumbar spine: the osteoporosis group and the control group, paired by age (P = 0.219) and physical activity (P = 0.611). There was no difference between the groups (P = 0.139) regarding falls reported in the previous 12 months. Functional mobility was evaluated through the Timed Up and Go Test. Postural balance was evaluated using a portable force platform in standard standing position, with eyes open and closed, for 60 s. Muscle strength was evaluated through an isokinetic dynamometer. This study shows that there is no difference in knee muscle strength and functional mobility (P = 0.121), postural balance with eyes open [mediolateral displacement (P = 0.286) and mean velocity of the center of pressure (COP) (P = 0.173)] and with eyes closed [mediolateral displacement (P = 0.163), and the mean velocity of displacement of the COP (P = 0.09)] in both groups. Subjects reporting falls had greater mediolateral displacement (P = 0.028) in both groups. Postmenopausal women aged between 55 and 65 years do not present changes in postural balance irrespective of lumbar osteoporosis. Greater COP mediolateral displacement is related to the occurrence of falls in postmenopausal women in the previous year.