Introduction: Motion analysis can be used to gain information needed for disease diagnosis as well as for the design and evaluation of intervention strategies in patients with hip osteoarthritis (HOA). Thereby, joint kinematics might be of great interest due to their discriminative capacity and accessibility, especially with regard to the growing usage of wearable sensors for motion analysis. So far, no comprehensive literature review on lower limb joint kinematics of patients with HOA exists. Thus, the aim of this systematic review and meta-analysis was to synthesise existing literature on lower body joint kinematics of persons with HOA compared to those of healthy controls during locomotion tasks.Methods: Three databases were searched for studies on pelvis, hip, knee and ankle kinematics in subjects with HOA compared to healthy controls during locomotion tasks. Standardised mean differences were calculated and pooled using a random-effects model. Where possible, subgroup analyses were conducted. Risk of bias was assessed with the Downs and Black checklist.Results and Discussion: A total of 47 reports from 35 individual studies were included in this review. Most studies analysed walking and only a few studies analysed stair walking or turning while walking. Most group differences were found in ipsi- and contralateral three-dimensional hip and sagittal knee angles with reduced ranges of motion in HOA subjects. Differences between subjects with mild to moderate and severe HOA were found, with larger effects in severe HOA subjects. Additionally, stair walking and turning while walking might be promising extensions in clinical gait analysis due to their elevated requirements for joint mobility. Large between-study heterogeneity was observed, and future studies have to clarify the effects of OA severity, laterality, age, gender, study design and movement execution on lower limb joint kinematics.Systematic Review Registration: PROSPERO (CRD42021238237).

Hip Osteoarthritis (HOA) is a common joint disease with serious impact on the quality of life of the affected persons. Additionally, persons with HOA often show alterations in gait biomechanics. Developing effective conservative treatment strategies is of paramount importance, as joint replacement is only indicated for end-stage HOA. In contrast to knee osteoarthritis, little is known about the effectiveness of hip bracing for the management of HOA. Studies analysing mechanically unloading hip braces partly showed beneficial results. However, methodological limitations of these studies, such as small sample sizes or lack of control groups, limit the applicability of the results. Additionally, mechanically unloading braces might impose restrictions on motion and comfort and thus, might not be suitable for people with only mild or moderate symptoms. The aim of this study was to comprehensively quantify the effects of unilateral HOA as well as functional hip bracing on gait biomechanics, pain, proprioception and functional capacity in people with mild to moderate HOA. Hip and pelvis biomechanics during walking were analysed in 21 subjects with mild to moderate HOA under three bracing conditions: unbraced, immediately after brace application and after 1 week of brace usage. Additionally, pain, hip proprioception and functional capacity were assessed. A matched group of 21 healthy subjects was included as reference. Kinematic and kinetic data were collected using a 16-camera infrared motion capturing system and two force plates. Visual analogue scales, an angle reproduction test and a 6-min walking test were applied to measure pain, hip proprioception and functional capacity, respectively. Subjects with HOA walked slower, with reduced step length, sagittal hip range of motion and peak extension angle and had a reduced functional capacity. After 1 week of brace application step length, walking speed and functional capacity were significantly increased. Additionally, pain perception was significantly lower in the intervention period. These results encourage the application of functional hip braces in the management of mild to moderate HOA. However, as key parameters of HOA gait such as a reduced peak extension angle remained unchanged, the underlying mechanisms remain partly unclear and have to be considered in the future.

Background and Objectives: Sit-to-Stand (STS) movements are fundamental activities of daily living. As STS movements can be physically demanding especially for the elderly, bi- and unilateral STS movements are frequently used in motor tests to measure lower limb strength. In contrast to bilateral STS movements, the knee joint loads occurring during unilateral STS movements as well as the influences of chair height or lower limb dominance are still unknown. Methods: In a randomized study approach knee joint loads during unilateral STS movements from three different chair heights have been analyzed using biomechanical motion analysis in a population of 19 healthy middle-aged adults. Additionally, the influence of lower limb dominance and the level of perceived exertion have been investigated. Results: Lower limb dominance had no effect on knee joint load. In contrast, chair height significantly affected the peak shear forces in anterior (high: 3.94 ± 0.63 N/kg; low: 4.09 ± 0.61 N/kg) and lateral (high: 1.52 ± 0.79 N/kg; low: 1.78 ± 0.88 N/kg) direction as well as the peak knee adduction moment (high: 0.56 ± 0.29 Nm/kg; low: 0.65 ± 0.32 Nm/kg). Additionally, chair height but not limb dominance significantly affected the level of perceived exertion (high: 11.1 ± 2.8; low: 12.5 ± 3.5). Conclusion: The detected knee joint loads occurring during a unilateral STS movements are similar to those of other activities of daily living like e.g. stair ascent and thus, unilateral STS movements are applicable for usage in motor tests for middle-aged subjects. While lower limb dominance has no impact on the knee joint load, lower chair heights increase the load on the knee joint. Therefore, chair height should be considered when using unilateral STS movements in motor tests.

Stair walking is more demanding than level walking, and differences have been found between steady-state stair walking and gait-to-stair or stair-to-gait transition. However, there is limited knowledge on steady-state stair walking biomechanics in people with hip osteoarthritis (HOA) as all existing data were obtained during gait-to-stair transition. The aim of the present study was to investigate the effects of mild-to-moderate HOA on hip and trunk biomechanics and dynamic balance during steady-state stair walking. Hip and trunk biomechanics and dynamic balance during steady-state stair walking were assessed in 21 participants with mild-to-moderate HOA and 21 age-matched healthy controls using an optoelectronic motion capture system and a custom-built instrumented six-step staircase. Dynamic balance was assessed using the inverted pendulum model with an extrapolated centre of mass. Differences between the two groups were analysed with an independent t-test either on discrete parameters or on entire time curves using statistical parametric mapping. The HOA group showed longer stride and stance phase durations during stair ascent and descent, and lower peak vertical CoM acceleration during stair descent vs. the control group. Trunk kinematics did not differ between groups. Lower frontal plane hip range of motion and hip internal rotation moment, but greater anterior margin of stability were observed during stair ascent in the HOA vs. control group. Mild-to-moderate HOA reduced frontal hip mobility but did not affect mediolateral dynamic balance during steady-state stair walking. Despite a lack of alterations in sagittal hip or trunk kinematics or dynamics, greater anterior margin of stability in HOA vs. control participants showed a more stable but potentially less efficient motion during stair ascent. Lastly, lower vertical acceleration during stair descent might reduce impact and joint loading at initial contact. Future studies should analyse gait efficiency and joint loading, and the effect of HOA severity and muscle force capacity on steady-state stair walking biomechanics in people with HOA.

Turning movements are frequently encountered during daily life and require more frontal and transverse hip mobility than straight walking. Thus, analysis of turning might be an insightful addition in the evaluation of conservative treatment approaches for hip osteoarthritis patients. The study objective was to quantify the effects of mild-to-moderate symptomatic hip osteoarthritis on lower-body turning biomechanics and evaluate the effects of hip bracing in this cohort. Biomechanical analysis of 90° step and spin turns in 21 persons with hip osteoarthritis and 21 healthy controls (case-control-study) and intervention study on the effects of hip bracing in hip osteoarthritis participants. Hip and knee kinematics and dynamics were compared using independent sample t-tests or one-way repeated measure ANOVAs. Persons with hip osteoarthritis have reduced peak hip extension and sagittal and transverse hip range of motion during turning. During the spin turn reduced hip adduction and frontal hip range of motion were found. Bracing increased the movement velocity at turn initiation and limited the transverse hip range of motion during both turns but increased knee peak adduction and internal rotation moments during spin turns. Persons with hip osteoarthritis present altered hip kinematics during 90° spin turns in all movement planes. Their inclusion during clinical movement analysis might facilitate the detection of mobility deficits at an early disease stage. Bracing led to higher movement velocity at turn initiation without increasing load at the hip joint and reduced transverse hip range of motion, avoiding the painful reaching of range of motion endpoints.

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.