Lower‐limb joint mechanics after total hip arthroplasty during sitting and standing tasks

Abstract

While the effect of total hip arthroplasty on the operated limb mechanics is well documented, little is known on its effect on the contralateral limb. The purpose of this study was to measure the joint mechanics of both lower limbs during the tasks of sit-tostand and stand-to-sit. Twenty total hip arthroplasty patients and 20 control participants performed three trials of each task from which 3D lower-limb joint kinematics and kinetics were obtained. Total hip arthroplasty patients exhibited lower operated-hip joint flexion, extension moments, and power, occurring most frequently near seat-on and seat-off. Despite these reduced kinetic variables in the operated hip, the joints of the non-operated limb generated similar joint kinetics as the matched control participants. These results indicated the patients who underwent total hip arthroplasty could adopt a strategy that allowed them to reduce moments and power generated at the operated lower-limb joints without overcompensating with the non-operated leg. Although such a strategy may be desirable given that higher loads can increase friction and accelerate wear of the prosthesis, reduced loading may be an indication of inadequate muscle strength that needs to be addressed. reported that older adults stand up on average 65 times a day, making this task important to assess the overall function. Reduced lower-limb muscle strength greatly affects sit-to-stand biomechanics in healthy adults, 7,8 and since THA patients already demonstrate reduced peak torques in flexion, extension, and abduction in both operated and non-operated hips, 9 abnormal sitting and standing biomechanics and joint loading are expected. 10 This could contribute to the onset and/or development of disorders at other joints, such as the contralateral knee.11 Differences have been found in gait for hip range of motion 12 and pelvic obliquity.1 To our knowledge, no study has inquired into side differences in a sit-to-stand task. Therefore, our purpose was to measure 3D-kinematics and kinetics of lower-limb joints during sit-to-stand and standto-sit by comparing both limbs of THA patients with those of healthy, matched control participants.We hypothesized that extensor moments and powers would be lower on the operated side as compared to the control group. As asymmetries have been found in ground reaction forces for THA patients, 5 the non-operated limb was expected to have greater moments and powers at the hip and knee articulations to compensate for the operated side. For kinematics, we also hypothesized that THA patients would have a reduction in hip sagittal-plane range of motion and peak hip flexion, as this group already demonstrated this pattern during stair climbing. 13 METHODS ParticipantsTwenty patients that had THA 6-15 months prior to testing (10 men, 10 women; mean age 66.2 AE 6.7 years; mean BMI 27.2 AE 5 kg/m 2 ; mean post-operative testing 317 AE 85 days) participated. Exclusion criteria were: any surgeries at the other lower-limb joints, THA secondary to an infection, a frac...

Abnormal Joint Moment Distributions and Functional Performance During Sit‐to‐Stand in Femoroacetabular Impingement Patients

“…The patients with FAI in the current study performed the STS task with an increased time compared to the control participants, unlike post‐THA [10] and hip OA [9] patients who did not demonstrate differences in total time needed to perform the STS task when compared to controls. Differences in the definition of the stance phase of the STS task between the current study and previous studies [9,10] may help to explain the differences in time needed to perform the STS task between studies. More specifically, the current study used the COM of the lower body to determine the beginning and end of the STS task, whereas previous studies used joint position or marker velocity data to determine the beginning and end of the STS task.…”

“…On the contrary, in the current study, measurement of time to perform the STS task was different between groups and can be used to assess functional performance between patients with FAI and control participants. It should be noted that both the patients and control groups in previous work [9,10], were older than the FAI and control groups used in the current study. Despite this difference in patient age between these previous studies [9,10] and the current study, patients in one of these previous studies were able to perform the STS task in an amount of time similar to that of healthy age‐matched controls [10].…”

“…It should be noted that both the patients and control groups in previous work [9,10], were older than the FAI and control groups used in the current study. Despite this difference in patient age between these previous studies [9,10] and the current study, patients in one of these previous studies were able to perform the STS task in an amount of time similar to that of healthy age‐matched controls [10]. Therefore, it can be suggested that the increased time to complete the STS task by the patients with FAI may be due to the morphological abnormalities present at the hip joint in those with FAI.…”

“…Biomechanical assessment of patients with FAI during ADL may provide researchers and clinicians with the knowledge needed PM R 9 (2017) 563-570 www.pmrjournal.org to detect this pathology at an early stage and possibly reduce the adverse effects of this pathology on hip joint health and function. Assessment of biomechanical function during the sitto-stand (STS) task has been performed in patients with patellofemoral joint OA [5], knee joint OA [6][7][8], and hip OA [9], as well as in patients after total hip arthroplasty [10] and in healthy adults [11][12][13][14], but it is yet to be assessed in the FAI population. The STS task has been suggested to be the most mechanically demanding ADL [15] and is performed by adults an average of 60 times per day [11].…”

“…Also, the STS task was proven to be a sensitive performance-based measure in evaluating asymmetries due to unilateral lower extremity pathology [16][17][18]. Despite the previous studies [9,10] assessing lower extremity mechanics and function during the STS task, the results of these studies are not conclusive across these patient groups, and therefore suggest that further work is needed to understand the effects of pathology on lower extremity mechanics during the STS task.…”