***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To study the hip muscle strength and cross sectional area ( CSA ) in men with hip osteoarthritis ( OA ) compared to age and sex matched healthy controls . METHODS Based on the American College of Rheumatology criteria regarding classification of hip OA , 27 men ( aged 47 - 64 yrs ) with unilateral or bilateral hip OA and 30 age matched r and omly selected healthy male controls were studied . The maximal isometric hip abductor , adductor , flexor , and extensor strength ( Nm ) at 0 degree of hip flexion in the supine position was determined with a dynamometer . The isokinetic hip flexion and extension strength ( peak torque , Nm ) was determined using angular velocities of 60 degrees /s and 120 degrees /s . The subjective severity of hip pain was rated by visual analog scale prior to the muscle strength test . CSA of the pelvic and thigh muscles was measured from magnetic resonance images . RESULTS The reliability of intraclass correlation coefficients for repeated measures of muscle strength varied from 0.70 to 0.94 in controls and from 0.84 to 0.98 in subjects with OA . Hip isometric adductor and abductor strength was 25 % and 31 % lower ( p < 0.001 ) in OA subjects than in controls , respectively . The hip isometric and isokinetic flexion strength was 18 - 22 % lower ( p < 0.01 ) in OA subjects than in controls , but extension strength did not differ between groups . In OA subjects , the hip flexion and extension isometric and isokinetic strength values were 13 - 22 % lower ( p < 0.05 ) on the more deteriorated side compared to the better side . CSA of the pelvic and thigh muscles did not differ between the groups . However , in OA subjects , the CSA of the pelvic and thigh muscles was 6 - 13 % less ( p < 0.05 to < 0.001 ) on the more severely affected hip compared to the better hip . CONCLUSION Men with hip OA have significantly lower abduction , adduction , and flexion muscle strength than controls . The decrease of muscle size and hip pain may contribute to the decrease of muscle strength in hip OA . Other possible underlying causes of the muscle weakness need to be studied OBJECTIVE To compare treadmill training with partial body-weight support ( TT-BWS ) and conventional physical therapy ( PT ) in ambulatory patients with hip arthroplasty . DESIGN R and omized controlled trial . SETTING Rehabilitation center . PARTICIPANTS Eighty patients with a fully loadable implant who could walk independently with crutches after unilateral total hip arthroplasty were r and omized to receive either TT-BWS ( treatment group ) or conventional PT ( controls ) , for 10 working days . INTERVENTIONS Each patient received 45 minutes of individualized PT , either treadmill training plus PT in the experimental or PT alone in the control group . MAIN OUTCOME MEASURES The Harris score , recorded by blind assessors , served as the primary outcome measure . Secondary outcome measures were the hip extension deficit , gait velocity , gait symmetry , affected hip abductor power ; hip abductor amplitude of electromyographic activation ; and the interval from surgery to ab and oning crutches . RESULTS At the end of training , the treatment group 's Harris score was 13.6 points higher ( P<.0001 ) than the control group 's score . Further , hip extension deficit was 6.8 degrees less ( P<.0001 ) , gait symmetry was 10 % greater ( P=.001 ) , affected hip abductor was stronger ( Medical Research Council grade s 4.24 vs 3.73 ; P<.0001 ) , and the amplitude of gluteus medius activity was 41.5 % greater ( P=.001 ) than those measures for controls . Gait velocity did not differ in the 2 groups . These significant differences in favor of the treatment group persisted at 3 and 12 months . The treatment group ab and oned crutches sooner than the control group ( 3 vs 8wk ) . In the treatment group , 39 patients finished treatment , 35 appeared at 3 , and 26 at 12 months for follow-up . In the control group , the corresponding numbers were 40 , 35 , and 24 patients , respectively . CONCLUSION TT-BWS is more effective than conventional PT at restoring symmetrical independent walking after hip replacement AIM Benefits of less damage of soft tissues and muscles in minimally invasive hip replacement lead to expectations of better results in gait rehabilitation . The aim of the study is to evaluate post-operative walking ability in terms of different surgical approaches . METHOD 16 patients underwent a minimally invasive total hip replacement ( MIS group ) and 16 other patients got a THA using a transgluteal approach ( st and ard group ) . Differences in functional indices of ground reaction forces and symmetry indices were measured one day pre-operatively as well as 8 , 14 and 28 weeks post-operatively . The results were compared between the surgical approaches and to an age-matched healthy control group . RESULTS There are significantly reduced pain symptoms and a higher functional ability in both surgical groups 8 weeks post-operatively . There are no differences in gait parameters between the surgical groups after 28 weeks . Trends in gait velocity , temporal parameters and in functional indices of ground reaction forces show advantages for the minimally invasive group 8 and 14 weeks post-operatively . Patients do not reach the age-matched control group . CONCLUSION Obviously the immediate post-operative advantages of minimally invasive hip replacement provide better chances for gait rehabilitation compared to the transgluteal approach . Due to the complexity of the problem clinical and gait analysis studies should be linked more closely This study examined the effect of the surgical approach used in  total hip arthroplasty ( THA )  on gait mechanics six months following surgery . Quantitative gait analysis was performed on 29 subjects : 10 anterolateral ( A-L ) and 10 posterolateral ( P-L ) THA patients and nine able-bodied , velocity-matched subjects . Discriminant function analysis was used to determine the distinction of the groups with respect to sagittal plane hip range of motion , index of symmetry , trunk inclination , pelvic drop , hip abduction , and foot progression angles . The A-L group had the largest trunk inclination ( 3.0+/-2.4 degrees ) and the smallest hip range of motion ( 34.0+/-7.4 degrees ) . Both THA groups demonstrated greater asymmetry as expressed by the smaller symmetry index ( 0.97+/-0.04 for A-L and 0.98+/-0.05 for the P-L ) than the able-bodied group ( 0.99+/-0.01 ) . The classification procedure correctly classified 89 % of the control group cases , 90 % of the A-L cases , and 50 % of the P-L cases . These results support the conclusion that six months following surgery , the gait of the majority ( 85 % ) of THA patients has not returned to normal . The A-L patients displayed distinct gait patterns , while a small percentage ( 30 % ) of the P-L patients demonstrated normal gait . While these differences are statistically significant , the clinical significance is unknown and linked to the duration that they persist OBJECTIVE To compare gait patterns in patients with total hip arthroplasty ( THA ) and surface hip arthroplasty .  DESIGN Observational study . SETTING Outpatient biomechanical laboratory . PARTICIPANTS Two groups of 10 surface hip arthroplasty and THA patients and 10 control subjects participated in the study ( N=30 ) . The patients were volunteers recruited from a larger r and omized study . INTERVENTIONS Not applicable . MAIN OUTCOMES MEASURES Gait patterns , hip abductor muscle strength , clinical outcomes , and radiographic analyses were compared between groups . RESULTS In the sagittal plane , the THA group showed a larger flexor moment and larger mechanical work in H2S and K3S power bursts compared with surface hip arthroplasty and control subjects . In the frontal plane , both THA and surface hip arthroplasty patients had smaller hip abductor muscles energy generation ( H3F ) than the control group . No difference was found for the hip abductor muscles strength . CONCLUSIONS In the THA group , the larger energy absorption in H2S and K3S would be a cost-effective mechanical adaptation to increase stability . The surface hip arthroplasty characteristics could allow the return to a more normative gait pattern compared with THA . The modification in the frontal plane in surface hip arthroplasty and THA would be related to the hip abductor muscles strength The hip-rating question naire was developed for the assessment of the outcome of total hip replacement . The purpose of this study was to evaluate its reproducibility , validity , and responsiveness . The question naire uses a 100-point scale in which equal weight is given to the domains of global or over-all impact of arthritis , pain , walking , and function . Ninety-eight patients were enrolled in the prospect i ve study and have been followed for at least three months ; sixty-two patients have been followed for six months ; and forty-two patients have been followed for one year .  Reproducibility was tested with the use of the kappa statistic in fifty patients whose condition was stable clinical ly , and it was found to be good or excellent both for individual questions and for the total score . The validity of the question naire was assessed by comparison with the scores from a six-minute walking-distance test and arthritis impact-measurement scales . The result of the six-minute walking-distance test correlated with the patient 's response concerning walking distance on the hip-rating question naire . The score for pain from the hip-rating question naire correlated well with the score for pain from the arthritis impact-measurement scales , and the total score from the hip-rating question naire correlated well with the total score from the arthritis impact-measurement scales . The score on the  hip-rating question naire was responsive to the change in the clinical condition of the patient , as indicated by a favorable index of responsiveness . The results of the question naire were sensitive enough to demonstrate differences among treatment groups with relatively small sample sizes . This question naire has the characteristics of a useful instrument for assessment of outcomes , such as that after an operation OBJECTIVE To quantify gait impairments in women with pregnancy-related pain in the pelvis which persisted post-partum . Design . Nine patients and nine healthy subjects were studied during treadmill walking at different velocities . BACKGROUND Walking problems in patients with pregnancy-related pain in the pelvis have been known to exist for a long time . To date , no quantitative gait studies have been conducted in this population . METHODS Maximum attainable walking velocity was determined , amplitudes of pelvic and thoracic rotations were calculated , and spectral analysis was used to assess the harmonicity of these rotations . Coordination between pelvic and thoracic rotations was characterized as mean relative Fourier phase and weighted coherence . RESULTS Maximum attainable walking velocity was highly variable between patients , but on average significantly lower than in healthy controls . Moreover , patients had a significantly lower mean relative Fourier phase ( again , highly variable ) and higher weighted coherence . The other parameters did not differ significantly between groups . CONCLUSIONS Coordination between pelvic and thoracic rotations in the transverse plane was affected in patients with pregnancy-related pain in the pelvis . Individual patients may apply different strategies during walking to cope with the underlying problems . RELEVANCE Pregnancy-related pain in the pelvis is poorly understood . Patients with this condition are known to have problems with locomotion . The present study reveals that gait coordination is altered . Theoretically , this underlines the importance of analysing coordination in pathological movement . Clinical ly , better underst and ing the gait problems of women with pregnancy-related pain in the pelvis may contribute to more appropriate treatments Purpose sPost arthroplasty gait analysis has up till now been performed on subjects walking slowly on flat ground rather than challenging them at faster speeds or walking uphill . We therefore asked : ( 1 ) Is there a measurable difference in the performance of  hip resurfacing arthroplasty ( HRA )  and  total hip arthroplasty ( THA ) limbs at patients ’ self-determined fastest walking speeds and steepest inclines ? and ( 2 ) Is there a relationship between the observed differences between the gait of HRA and THA implanted limbs and patient walking speeds and inclines . Methods In an ethically approved study we recruited patients with bilateral hip arthroplasties : one HRA and one THA . Nine subjects were assessed using an instrumented treadmill at a range of speeds and inclines by a blinded observer . The ground reaction forces of subjects were recorded and an age , sex and BMI matched control group was used for comparison . Results Increasing walking speed correlated strongly with between leg differences in weight acceptance ( r = 0.9 , p = 0.000 ) and push-off force ( r = 0.79 , p = 0.002 ) . HRA implanted limbs accepted significantly more weight at top walking speeds ( 1208 N ± 320 versus 1279 N ± 370 , p = 0.026 ) and pushed off with greater force when walking uphill ( 818 N ± 163 versus 855 ± 166 , p = 0.012 ) . HRA limbs more closely approximated to the gait of the normal control group . Conclusions Arthroplasty implants do have an impact on the gait characteristics of patients . Differences in gait are more likely to be evident when assessment is made at fast speeds and walking uphill . This study suggests that HRA may enable a more normal gait Although treatments for osteoarthritis of the knee are often directed at relieving pain , pain may cause patients to alter how they perform activities to decrease the loads on the joints . The knee-adduction moment is a 
    Output:
    
Compared to controls , reductions were identified in the operated hip in sagittal range of motion , peak extension , sagittal power generation , abduction moment and external rotation moment .
During stair ascent , these reductions did not become more apparent , although deficits in hip kinetics in all three planes were found .
Walking speed and step length were reduced compared to controls at longer-term follow-up , but not at short-term follow-up .
INTERPRETATION The hip abduction moment deficit was present both in level walking and in stair ascent in total hip arthroplasty patients compared to controls .
Reduced sagittal hip power generation and external rotation moment were also found , of which the clinical relevance remains to be established .