BACKGROUND: How the joints exactly move and interact and how this reflects PD-related gait abnormalities and the response to dopaminergic treatment is poorly understood. A detailed understanding of these kinematics can inform clinical management and treatment decisions. The aim of the study was to investigate the influence of different gait speeds and medication on/off conditions on inter-joint coordination, as well as kinematic differences throughout the whole gait cycle in well characterized pwPD.
METHODS: 29 controls and 29 PD patients during medication on, 8 of them also during medication off walked a straight walking path in slow, preferred and fast walking speeds. Gait data was collected using optical motion capture system. Kinematics of the hip and knee and coordinated hip-knee kinematics were evaluated using Statistical Parametric Mapping (SPM) and cyclograms (angle-angle plots). Values derived from cyclograms were compared using repeated-measures ANOVA for within group, and ttest for between group comparisons.
RESULTS: PD gait differed from controls mainly by lower knee range of motion (ROM). Adaptation to gait speed in PD was mainly achieved by increasing hip ROM. Regularity of gait was worse in PD but only during preferred speed. The ratios of different speed cyclograms were smaller in the PD groups. SPM analyses revealed that PD participants had smaller hip and knee angles during the swing phase, and PD participants reached peak hip flexion later than controls. Withdrawal of medication showed an exacerbation of only a few parameters.
CONCLUSIONS: Our findings demonstrate the potential of granular kinematic analyses, including > 1 joint, for disease and treatment monitoring in PD. Our approach can be extended to further mobility-limiting conditions and other joint combinations.
BACKGROUND: The study is registered in the German Clinical Trials Register (DRKS00022998, registered on 04 Sep 2020).

Wearable robots are emerging as a viable and effective solution for assisting and enabling people who suffer from balance and mobility disorders. Virtual prototyping is a powerful tool to design robots, preventing the costly iterative physical prototyping and testing. Design of wearable robots through modelling, however, often involves computationally expensive and error-prone multi-body simulations wrapped in an optimization framework to simulate human-robot-environment interactions. This paper proposes a framework to make the human-robot link segment system statically determinate, allowing for the closed-form inverse dynamics formulation of the link-segment model to be solved directly in order to simulate human-robot dynamic interactions. The paper also uses a technique developed by the authors to estimate the walking ground reactions from reference kinematic data, avoiding the need to measure them. The proposed framework is (a) computationally efficient and (b) transparent and easy to interpret, and (c) eliminates the need for optimization, detailed musculoskeletal modelling and measuring ground reaction forces for normal walking simulations. It is used to optimise the position of hip and ankle joints and the actuator torque-velocity requirements for a seven segments of a lower-limb wearable robot that is attached to the user at the shoes and pelvis. Gait measurements were carried out on six healthy subjects, and the data were used for design optimization and validation. The new technique promises to offer a significant advance in the way in which wearable robots can be designed.

AI-powered segmentation of hip and knee bony anatomy has revolutionized orthopedics, transforming pre-operative planning and post-operative assessment. Despite the remarkable advancements in AI algorithms for medical imaging, the potential for biases inherent within these models remains largely unexplored. This study tackles these concerns by thoroughly re-examining AI-driven segmentation for hip and knee bony anatomy. While advanced imaging modalities like CT and MRI offer comprehensive views, plain radiographs (X-rays) predominate the standard initial clinical assessment due to their widespread availability, low cost, and rapid acquisition. Hence, we focused on plain radiographs to ensure the utilization of our contribution in diverse healthcare settings, including those with limited access to advanced imaging technologies. This work provides insights into the underlying causes of biases in AI-based knee and hip image segmentation through an extensive evaluation, presenting targeted mitigation strategies to alleviate biases related to sex, race, and age, using an automatic segmentation that is fair, impartial, and safe in the context of AI. Our contribution can enhance inclusivity, ethical practices, equity, and an unbiased healthcare environment with advanced clinical outcomes, aiding decision-making and osteoarthritis research. Furthermore, we have made all the codes and datasets publicly and freely accessible to promote open scientific research.

We investigated the effect of robotic assistance in a postoperative change in hip offset and the incidence of trochanteric bursitis among total hip arthroplasty (THA) patients. As part of a retrospective study of a consecutive series of patients over a 3-year period, 211 patients (102 traditional; 109 robotic) between 2013 and 2016 who underwent posterior-lateral THA were reviewed. Hip offset was measured on preoperative and postoperative anterior-posterior (AP) pelvis radiographs. The absolute change in total hip offset was higher in patients undergoing non-robotic THA than in patients undergoing robotic THA (5.98 ± 4.47 mm vs 4.33 ± 3.98 mm; p = 0.008). The rate of symptomatic trochanteric bursitis (p = 0.02) and cortisone injection was higher in non-robotic THA patients than in robotic THA patients (p = 0.002). Robotic arm-assisted THA is associated with a decreased postoperative change in hip offset, incidence of symptomatic trochanteric bursitis, and bursal steroid injections. (Journal of Surgical Orthopaedic Advances 32(4):112-116, 2023).

BACKGROUND: This study investigated the effects of changes in motor skills from an educational video program on the kinematic and kinetic variables of the lower extremity joints and knee ligament load.
METHODS: Twenty male participants (age: 22.2 ± 2.60 y; height: 1.70 ± 6.2 m; weight: 65.4 ± 7.01 kg; BMI: 23.32 ± 2.49 [Formula: see text]) were instructed to run at 4.5 ± 0.2 m/s from a 5 m distance posterior to the force plate, land their foot on the force plate, and perform the cutting maneuver on the left. The educational video program for cutting maneuvers consisted of preparatory posture, foot landing orientation, gaze and trunk directions, soft landing, and eversion angle. The measured variables were the angle, angular velocity of lower extremity joints, ground reaction force (GRF), moment, and anterior cruciate ligament (ACL) and medial collateral ligament (MCL) forces through musculoskeletal modeling.
RESULTS: After the video feedback, the hip joint angles increased in flexion, abduction, and external rotation (p < 0.05), and the angular velocity increased in extension (p < 0.05). The ankle joint angles increased in dorsiflexion (p < 0.05), and the angular velocity decreased in dorsiflexion (p < 0.05) but increased in abduction (p < 0.05). The GRF increased in the anterior-posterior and medial-lateral directions and decreased vertically (p < 0.05). The hip joint moments decreased in extension and external rotation (p < 0.05) but increased in adduction (p < 0.05). The knee joint moments were decreased in extension, adduction, and external rotation (p < 0.05). The abduction moment of the ankle joint decreased (p < 0.001). There were differences in the support zone corresponding to 64‒87% of the hip frontal moment (p < 0.001) and 32‒100% of the hip horizontal moment (p < 0.001) and differences corresponding to 32‒100% of the knee frontal moment and 21‒100% of the knee horizontal moment (p < 0.001). The GRF varied in the support zone at 44‒95% in the medial-lateral direction and at 17‒43% and 73‒100% in the vertical direction (p < 0.001).
CONCLUSIONS: Injury prevention feedback reduced the load on the lower extremity joints during cutting maneuvers, which reduced the knee ligament load, mainly on the MCL.

UNASSIGNED: In upright standing, spinopelvic mismatch is compensated by hip extension. However, few studies have investigated the reciprocal relationship between the sagittal alignment of the hip joints and spinopelvic mismatch during upright standing in humans. Our study aims to investigate (I) the relationship between spinopelvic mismatch and hip extension and (II) whether insufficient hip extension against spinopelvic mismatch, i.e., pelvic incidence (PI)-lumbar lordosis (LL), affects trunk inclination in upright standing.
UNASSIGNED: This study was a retrospective cross-sectional study. We included 398 consecutive female patients treated for osteoporosis at our outpatient department between November 2017 and June 2022. Patients with any of the following were excluded from the study: (I) those whose plain whole-spine radiographs did not cover the femurs, (II) those with fractures in the vertebrae or lower extremities, (III) those with a history of surgery of the spine or of the lower extremities, (IV) those with scoliosis with a Cobb angle ≥10° in the anteroposterior radiograph, and (V) those with transitional vertebrae. Sixty-two patients were divided into normal and malalignment groups based on their sagittal spinal alignment. The patients underwent plain whole-spine radiography as a routine examination. A linear approximation between the pelvic femoral angle (PFA), representing hip extension, and PI-LL was obtained in both groups. The optimal PFA of each patient was obtained by substituting the PI-LL into the linear approximation of the normal group. The difference between the optimal and measured PFA was defined as the ΔPFA for each patient. The correlation between the ΔPFA and sagittal vertical axis (SVA) was evaluated in both groups.
UNASSIGNED: The PFA and PI-LL were correlated in both groups. The malalignment group had a significantly greater ΔPFA than the normal group. ΔPFA was correlated with SVA only in the malalignment group.
UNASSIGNED: The magnitude of the ΔPFA indicated insufficient hip extension to compensate for the spinopelvic mismatch during upright standing.

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In total hip arthroplasty (THA), determining the center of rotation (COR) and diameter of the hip joint (acetabulum and femoral head) is essential to restore patient biomechanics. This study investigates on-the-fly determination of hip COR and size, using off-the-shelf augmented reality (AR) hardware. An AR head-mounted device (HMD) was configured with inside-out infrared tracking enabling the determination of surface coordinates using a handheld stylus. Two investigators examined 10 prosthetic femoral heads and cups, and 10 human femurs. The HMD calculated the diameter and COR through sphere fitting. Results were compared to data obtained from either verified prosthetic geometry or post-hoc CT analysis. Repeated single-observer measurements showed a mean diameter error of 0.63 mm ± 0.48 mm for the prosthetic heads and 0.54 mm ± 0.39 mm for the cups. Inter-observer comparison yielded mean diameter errors of 0.28 mm ± 0.71 mm and 1.82 mm ± 1.42 mm for the heads and cups, respectively. Cadaver testing found a mean COR error of 3.09 mm ± 1.18 mm and a diameter error of 1.10 mm ± 0.90 mm. Intra- and inter-observer reliability averaged below 2 mm. AR-based surface mapping using HMD proved accurate and reliable in determining the diameter of THA components with promise in identifying COR and diameter of osteoarthritic femoral heads.

The 3 primary factors involved with preservation of the hip joint are femoroacetabular impingement (FAI), hip dysplasia, and femoral torsion abnormalities. Each of these factors affects the health of the acetabular labrum and femoroacetabular cartilage. The appropriate surgical treatments for each of these factors include arthroscopic or open femoroplasty or acetabuloplasty for FAI, periacetabular osteotomy (PAO) for acetabular dysplasia, and de-rotational femoral osteotomy for femoral torsion abnormalities. When evaluating patients with prearthritic hip conditions, orthopaedic surgeons should be aware of the various factors involved in hip joint preservation and, if surgery is indicated, surgeons should be sure to address all factors that need surgical treatment rather than focusing on the most obvious issue or injury (e.g., a labral tear). The purpose of this infographic is to illustrate the importance of the factors involved in hip joint preservation and the appropriate treatments for pathology in any of these factors.

Transient osteoporosis of the hip (TOH) is an important but often neglected cause of hip pain, which can gradually lead to debilitating mobility and carries risks such as fracture or avascular necrosis. A 39-year-old woman presented to the Rheumatology department two weeks post-cesarean delivery, reporting the onset of left mechanical hip pain since the 33rd week of pregnancy. After delivery, similar complaints emerged on the right side. Hip X-ray showed a decrease in bone density in the left hip. Later, Magnetic Resonance Imaging revealed bilateral bone marrow edema in both proximal femurs. The diagnosis of TOH was established, and the patient was treated with conservative measures. Seven months later, she was asymptomatic. Pregnancy is a recognized risk factor for TOH, especially in the last trimester. It is an important differential diagnosis to consider in cases of hip pain in pregnant or newly breastfeeding women.