Effects of Hip Abductor Strengthening on Musculoskeletal Loading in Hip Dysplasia Patients after Total Hip Replacement

Medial and lateral knee contact forces during walking, stair ascent and stair descent are more affected by contact locations than tibiofemoral alignment in knee osteoarthritis patients with varus malalignment

Introduction: Knee OA progression is related to medial knee contact forces, which can be altered by anatomical parameters of tibiofemoral alignment and contact point locations. There is limited and controversial literature on medial-lateral force distribution and the effect of anatomical parameters, especially in motor activities different from walking. We analyzed the effect of tibiofemoral alignment and contact point locations on knee contact forces, and the medial-lateral force distribution in knee OA subjects with varus malalignment during walking, stair ascending and stair descending. Methods: Fifty-one knee OA subjects with varus malalignment underwent weight-bearing radiographs and motion capture during walking, stair ascending and stair descending. We created a set of four musculoskeletal models per subject with increasing level of personalization, and calculated medial and lateral knee contact forces. To analyze the effect of the anatomical parameters, statistically-significant differences in knee contact forces among models were evaluated. Then, to analyze the force distribution, the medial-to-total contact force ratios were calculated from the fully-informed models. In addition, a multiple regression analysis was performed to evaluate correlations between forces and anatomical parameters. Results: The anatomical parameters significantly affected the knee contact forces. However, the contact points decreased medial forces and increased lateral forces and led to more marked variations compared to tibiofemoral alignment, which produced an opposite effect. The forces were less medially-distributed during stair negotiation, with medial-to-total ratios below 50% at force peaks. The anatomical parameters explained 30%-67% of the variability in the knee forces, where the medial contact points were the best predictors of medial contact forces. Discussion: Including personalized locations of contact points is crucial when analyzing knee contact forces in subjects with varus malalignment, and especially the medial contact points have a major effect on the forces rather than tibiofemoral alignment. Remarkably, the medial-lateral force distribution depends on the motor activity, where stair ascending and descending show increased lateral forces that lead to less medially-distributed loads compared to walking.

Differences in hip musculoskeletal loads between limbs during daily activities in patients with 3D-printed hemipelvic reconstructions following tumor surgery

BACKGROUND

Anatomical custom-made prostheses, thanks to computer-aided design and 3D-printing technology, help improve osseointegration and reduce mechanical complications in bone reconstructions following bone tumors. A recent quantitative analysis of long-term recovery in patients with 3D-printed reconstructions following pelvic tumor surgery showed asymmetries in ground reaction forces between limbs during different motor activities, while standing very good motor performance and quality of life.

RESEARCH QUESTION

We analyzed hip contact forces and muscle forces in that cohort of six patients with an innovative custom-made reconstruction of the hemipelvis, and we tested the hypothesis that asymmetries in ground reaction forces would result in more marked differences in musculoskeletal forces.

METHODS

State-of-the-art musculoskeletal modeling in an optimization-based inverse-dynamics workflow was used to calculate hip contact forces and muscle forces during five motor activities, and the differences between limbs were statistically evaluated across the motor activity cycles and on the force peaks.

RESULTS

The musculoskeletal loads were found to be not symmetric, as hip loads were generally higher in the contralateral limb. We found significant differences in considerable portions of the motor activities cycles except squat, load symmetry indices indicating a load increase (median up to 25%) on the contralateral limb, especially during stair descent and chair rise/sit, and significantly higher values in the contralateral limb at force peaks.

SIGNIFICANCE

We confirmed the hypothesis that residual asymmetries found in ground reaction forces were amplified when hip musculoskeletal loads were investigated, reflecting a shift of the loads toward the intact limb. Despite the general trend of higher loads found in the contralateral hip, this cannot be considered a risk of overloading, as both hips supported loads in a physiological range or lower, indicating a likely optimal recovery.

Analysis of contact pressure in a 3D model of dual-mobility hip joint prosthesis under a gait cycle

Hip joint prostheses are used to replace hip joint function in the human body. The latest dual-mobility hip joint prosthesis has an additional component of an outer liner that acts as a cover for the liner component. Research on the contact pressure generated on the latest model of a dual-mobility hip joint prosthesis under a gait cycle has never been done before. The model is made of ultrahigh molecular weight polyethylene (UHMWPE) on the inner liner and 316L stainless steel (SS 316L) on the outer liner and acetabular cup. Simulation modeling using the finite element method is considered static loading with an implicit solver for studying the geometric parameter design of dual-mobility hip joint prostheses. In this study, simulation modeling was carried out by applying varying inclination angles of 30°, 40°, 45°, 50°, 60°, and 70° to the acetabular cup component. Three-dimensional loads were placed on femoral head reference points with variations of femoral head diameter used at 22 mm, 28 mm, and 32 mm. The results in the inner surface of the inner liner, the outer surface of the outer liner, and the inner surface of the acetabular cup showed that the variations in inclination angle do not have a major effect on the maximum contact pressure value on the liner component, where the acetabular cup with an inclination angle of 45° can reduce contact pressure more than the other studied inclination angle variations. In addition, it was found that the 22 mm diameter of the femoral head increases the contact pressure. The use of a larger diameter femoral head with an acetabular cup configuration at a 45° inclination can minimize the risk of implant failure due to wear.

Dynamic Analysis and Trajectory Tracking Control for a Parallel Manipulator with Joint Friction

To overcome the bearing capacity deficiencies of traditional serial hip joint simulators, complex trajectory simulation, among others, as well as a parallel manipulator with two pairs of artificial hip joints and two moving platforms are proposed. The movements and driving forces of the parallel manipulator under the required motion and loading are studied to provide a basis for further research. In this study, the modeling and analysis of inverse kinematics and dynamics for a parallel manipulator with joint friction are derived. In the inverse kinematic model, kinematic relationships between the linear module slider and the moving platform are established, and expressions for the slider are deduced. Subsequently, by analyzing the frictional forces of the artificial hip joint and thrust ball bearing, a rigid body dynamics model of the parallel manipulator with joint friction is established, which is subsequently decomposed into four driving torques associated with the moving platform, joint lever, slider, and screw. Finally, the difference in the kinematic performance between the two moving platforms is analyzed using numerical simulations and experiments, and the accuracy of the established model is verified.

Effect of Rehabilitation Nursing under the Guidance of the Health Action Process Approach Model on Perioperative Nursing Effect of Artificial Hip Arthroplasty: Effect on Promoting Quality of Life and Postoperative Rehabilitation

Objective

To explore the influence of rehabilitation nursing under the guidance of Health Action Process Approach (HAPA) model on the perioperative nursing effect of artificial hip replacement and to analyze the effect of this nursing model on the quality of life and postoperative rehabilitation of patients undergoing artificial hip replacement.

Methods

A total of 200 patients with hip arthroplasty treated in our hospital from January 2019 to July 2021 were enrolled. The patients were randomly assigned into the control group and study group. The former received routine nursing, and the latter received rehabilitation nursing under the guidance of the HAPA model. Nursing satisfaction, pain score, Harris hip function score, timed stand-up-walk test, MBI score, and quality of life score were compared.

Results

First of all, we compared the nursing satisfaction. In the study group, 86 cases were very satisfied, 8 cases were satisfied, and 6 cases were general; the satisfaction rate was 100%. In the control group, 48 cases were very satisfied, 22 cases were satisfied, 12 cases were general, and 18 cases were dissatisfied; the satisfaction rate was 82.0%. The nursing satisfaction in the study group was higher compared to that in the control group (P < 0.05). Secondly, we compared the pain scores. Before nursing, there exhibited no significant difference (P > 0.05). After nursing, the pain score of the two groups increased. Moreover, the pain score of the study group at discharge and 1 month, 3 months, and 6 months after operation was lower compared to that of the control group (P < 0.05). Before nursing, there exhibited no significant difference in the Harris hip joint function score (P > 0.05). After nursing, the Harris hip function score increased. Furthermore, the Harris hip function score of the study group at discharge and 1 month, 3 months, and 6 months after operation was higher compared to that of the control group (P < 0.05). In terms of the timed stand-up-walking test, there exhibited no significant difference before nursing (P > 0.05). After nursing, the time of the timed stand-up-walk test in both groups decreased. And the timed stand-up-walk test at discharge and 1 month, 3 months, and 6 months after operation in the study group was lower compared to that in the control group (P < 0.05). Compared with the MBI scores, there exhibited no significant difference before nursing (P > 0.05). After nursing, the MBI scores increased. Of note, the MBI scores of the study group at discharge and 1 month, 3 months, and 6 months after operation were higher compared to those of the control group (P < 0.05). Finally, we compared the scores of life quality. Before nursing, there exhibited no significant difference (P > 0.05). After nursing, the scores of life quality decreased. The scores of physiological function, psychological function, social function, and health self-cognition in the study group were lower compared to those in the control group (P < 0.05).

Conclusion

The perioperative rehabilitation nursing program of artificial hip replacement for the elderly based on the HAPA model is feasible, which can effectively enhance the functional recovery of hip joint, promote the ability of self-care of daily life, relieve pain and anxiety, and help to achieve dynamic balance and gait stability in the early stage. The rehabilitation program is better than routine nursing. As a new social cognitive model, the HAPA model is applied to the rehabilitation nursing environment of hip replacement from the aspect of social cognitive behavior, which can help to enhance the rehabilitation behavior of elderly patients, playing an important role in the rehabilitation effect of perioperative nursing.