Resultant Joint Reaction Forces Research Articles

Standard and special liner in primary hip arthroplasty : Current study and survey results from the German Arthroplasty Registry (EPRD)

Instability constitutes the main reason for revision hip arthroplasties. Modified polyethylene liners are designed to improve the stability of ahip replacement. In July 2022 The Bone & Joint Journal published astudy with data of the German Arthroplasty Registry (EPRD). The study investigated mechanical failure of standard and modified liner designs in primary, cementless total hip arthroplasty. Following the study, the EPRD conducted asurvey of German clinics to research the utilization of lipped liners in primary total hip replacement. The liner study included 151,096 primary, elective, cementless total hip arthroplasties. Data from November 2012 to November 2020 were obtained from the EPRD. Standard polyethylene liners were compared with lipped, angulated, offset and angulated/offset inlays. Cumulative incidences for endpoint revision due to mechanical complication were calculated with acompeting risk analysis. The influence of other variables was investigated with amultivariate Cox regression. In the following online survey, 237 out of 789 hospitals completed aform. In our analysis, only offset liners were, compared to standard liners, associated with areduced risk of mechanical failure in ashort to medium follow up. However, the resultant joint reaction force is increased with offset liners due to the lateralization of the hip center of rotation. Thus, the long-term performance of offset liners needs to be observed. Our survey indicated that lipped liners were implanted more often if the posterior approach was used. Moreover, lipped liners were mostly positioned with the elevated rim in the biomechanically less optimal posterior-superior quadrant. To improve stability it is suggested to position the elevated rim in the posterior-inferior quadrant.

Femoral version deformities alter joint reaction forces in dysplastic hips during gait

Developmental dysplasia of the hip (DDH) causes hip instability and early-onset osteoarthritis. The focus on pathomechanics in DDH has centered on the shallow acetabulum, however there is growing awareness of the role of femoral deformities in joint damage. The objective of this study was to determine the influence of femoral version (FV) on the muscle and joint reaction forces (JRFs) of dysplastic hips during gait. Magnetic resonance images, in-vivo gait data, and musculoskeletal models were used to calculate JRFs and simulate changes due to varying FV deformities. Rotation about the long axis of the femur was added in the musculoskeletal models to simulate FV values from −5° (relative retroversion) to + 35° (increased anteversion). In our simulations, FV deformities caused the largest changes to the anteroposterior and resultant JRFs. From a normal FV of 15°, a 15° increase in femoral anteversion caused JRFs to be less posterior in early stance (Δ = 0.43 ± 0.22 xbodyweight) and more anterior in late stance (Δ = 0.60 ± 14 xbodyweight). Relative retroversion caused anteroposterior changes that were similar to anteversion in early stance but opposite in late stance. Resultant JRFs experienced the largest changes during late stance where anteversion raised the peak by 0.48 ± 0.15 xbodyweight and relative retroversion lowered the peak by 0.32 ± 0.30 xbodyweight. Increasing anteversion increased hip flexor and abductor muscle forces, which caused the changes in JRFs. Identifying how FV deformities influence hip joint loading can elucidate their role in the mechanisms of hip degeneration in patients with DDH.

Effect of simulated rehabilitation on hip joint loading during single limb squat in patients with hip dysplasia

Rehabilitation for patients with developmental dysplasia of the hip (DDH) addresses modifiable factors in an effort to reduce symptoms and prevent or delay the development of osteoarthritis, yet its effect on joint mechanics remains unknown. Our objective was to establish how rehabilitation (muscle strengthening and movement training), simulated with a musculoskeletal model and probabilistic analyses, alters hip joint reaction forces (JRF) in patients with DDH during a single limb squat. In four patients with DDH, hip abductor strengthening was simulated by increasing the maximum isometric force value between 0 and 32.6% and movement training was simulated by decreasing the hip adduction angle between 0 and 10° relative to baseline. 2,000 Monte Carlo simulations were performed separately to simulate strengthening and movement training, from which 99% confidence bounds and sensitivity factors were calculated. Our results indicated that simulated movement training aimed at decreasing hip adduction had a substantially larger influence on hip JRF than strengthening, as indicated by 99% confidence bounds of the resultant JRF (0.88 ± 0.55 xBW vs. 0.31 ± 0.12 xBW, respectively). Relative to baseline, movement training that resulted in a 10° decrease in hip adduction decreased the resultant JRF by 0.78 ± 0.65 xBW, while strengthening the abductors by 17.6% increased resultant JRF by 0.18 ± 0.06 xBW. To our knowledge, these results are the first to provide evidence pertaining to the effect of rehabilitation on joint mechanics in patients with DDH and can be used to inform more targeted interventions.

Dysplastic hip anatomy alters muscle moment arm lengths, lines of action, and contributions to joint reaction forces during gait

Developmental dysplasia of the hip (DDH) is characterized by abnormal bony anatomy, which causes detrimental hip joint loading and leads to secondary osteoarthritis. Hip joint loading depends, in part, on muscle-induced joint reaction forces (JRFs), and therefore, is influenced by hip muscle moment arm lengths (MALs) and lines of action (LoAs). The current study used subject-specific musculoskeletal models and in-vivo motion analysis to quantify the effects of DDH bony anatomy on dynamic muscle MALs, LoAs, and their contributions to JRF peaks during early (~17%) and late-stance (~52%) of gait. Compared to healthy hips (N = 15, 16–39 y/o), the abductor muscles in patients with untreated DDH (N = 15, 16–39 y/o) had smaller abduction MALs (e.g. anterior gluteus medius, 35.3 vs. 41.6 mm in early stance, 45.4 vs. 52.6 mm late stance, p ≤ 0.01) and more medially-directed LoAs. Abduction-adduction and rotation MALs also differed for major hip flexors such as rectus femoris and iliacus. The altered MALs in DDH corresponded to higher hip abductor forces, medial JRFs (1.26 vs. 0.87 × BW early stance, p = 0.03), and resultant JRFs (5.71 vs. 4.97 × BW late stance, p = 0.05). DDH anatomy not only affected hip muscle force generation in the primary plane of function, but also their out-of-plane mechanics, which collectively elevated JRFs. Overall, hip muscle MALs and their contributions to JRFs were significantly altered by DDH bony anatomy. Therefore, to better understand the mechanisms of joint degeneration and improve the efficacy of treatments for DDH, the dynamic anatomy-force relationships and multi-planar functions of the whole hip musculature must be collectively considered.

The influence of musculoskeletal forces on the growth of the prenatal cortex in the ilium: a finite element study

Remodelling and adaptation of bone within the pelvis is believed to be influenced by the mechanical strains generated during locomotion. Variation in the cortical bone thickness observed in the prenatal ilium has been linked to the musculoskeletal loading associated with in utero movements; for example the development of a thicker gluteal cortex is a possible response to contractions of the gluteal muscles. This study examines if the strains generated in the prenatal iliac cortex due to musculoskeletal loading in utero are capable of initiating bone remodelling to either maintain homeostasis or form new bone. Computational modelling techniques were used firstly to predict the muscle forces and resultant joint reaction force acting on the pelvis during a range of in utero movements. Finite element analyses were subsequently performed to calculate the von Mises strains induced in the prenatal ilium. The results demonstrated that strains generated in the iliac cortex were above the thresholds suggested to regulate bone remodelling to either maintain homeostasis or form new bone. Further simulations are required to investigate the extent to which the heterogeneous cortex forms in response to these strains (i.e., remodelling) or if developmental bone modelling plays a more pivotal role.

Evaluation of musculoskeletal modelling parameters of the shoulder complex during humeral abduction above 90°

Based on electromyographic data and force measurements within the shoulder joint, there is an indication that muscle and resulting joint reaction forces keep increasing over an abduction angle of 90°. In inverse dynamics models, no single parameter could be attributed to simulate this force behaviour accordingly. The aim of this work is to implement kinematic, kinetic and muscle model modifications to an existing model of the shoulder (AnyBody™) and assess their single and combined effects during abduction up to 140° humeral elevation. The kinematics and the EMG activity of 10 test subjects were measured during humeral abduction. Six modifications were implemented in the model: alternative wrapping of the virtual deltoid muscle elements, utilization of a three element Hill model, strength scaling, motion capture driven clavicle elevation/protraction, translation of the GH joint in dependency of the acting forces and an alteration of the scapula/clavicle rhythm. From the six modifications, 16 different combinations were considered. Parameter combinations with the Hill model changed the resultant GH joint reaction force and led to an increase in force during abduction of the humerus above 90°. Under the premise of muscle activities and forces within the GH joint rising after 90° of humeral abduction, we propose that the Hill type muscle model is a crucial parameter for accurately modelling the shoulder. Furthermore, the outcome of this study indicates that the Hill model induces the co-contraction of the muscles of the shoulder without the need of an additional stability criterion for an inverse dynamics approach.

Musculoskeletal models with generic and subject-specific geometry estimate different joint biomechanics in dysplastic hips

Optimizing the geometric complexity of musculoskeletal models is important for reliable yet feasible estimation of joint biomechanics. This study investigated the effects of subject-specific model geometry on hip joint reaction forces (JRFs) and muscle forces in patients with developmental dysplasia of the hip (DDH) and healthy controls. For nine DDH and nine control subjects, three models were created with increasingly subject-specific pelvis geometry, hip joint center locations and muscle attachments. Hip JRFs and muscle forces during a gait cycle were compared among the models. For DDH subjects, resultant JRFs from highly specific models including subject-specific pelvis geometry, joint locations and muscle attachments were not significantly different compared to models using generic geometry in early stance, but were significantly higher in late stance (p = 0.03). Estimates from moderately specific models using CT-informed scaling of generic pelvis geometry were not significantly different from low specificity models using generic geometry scaled with skin markers. For controls, resultant JRFs in early stance from highly specific models were significantly lower than moderate and low specificity models (p ≤ 0.02) with no significant differences in late stance. Inter-model JRF differences were larger for DDH subjects than controls. Inter-model differences for JRF components and muscle forces were similar to resultant JRFs. Incorporating subject-specific pelvis geometry significantly affects JRF and muscle force estimates in both DDH and control groups, which may be especially important for reliable estimation of pathomechanics in dysplastic hips.

The effects of Navy ship ladder descent on the knee internal joint reaction forces

ABSTRACTMilitary populations may be at risk for developing knee osteoarthritis and other knee problems when descending a Navy ship ladder, which differs from traditional stairs due to non-overlapping treads, a larger rise and a steeper inclination angle. The purpose of this study was to develop a forward dynamic model of the descent of a Navy ship ladder to determine how this motion affects the internal knee reaction forces and how altering the hamstring/quadriceps ratio affects the internal joint reaction forces in the knee. Kinematic and kinetic data were collected from three male sailors descending a replica of a Navy ship ladder and were used as input into a model constructed in OpenSim. The peak resultant joint reaction force was 6.6 × BW, which was greater than values reported in the literature in traditional stairs. Peak compressive and anterior joint reaction forces, 4.05 × BW and 5.46 × BW, respectively, were greater than reported values for a squat, a motion similar to descending a ship ladder. The average peak vertical and anterior internal joint reaction force at the knee were 4.05 × BW and 5.46 × BW, respectively. The resultant joint reaction forces calculated from the ladder descent were greater than stair descent and squatting. Little effects were found in the joint reaction forces after adjusting the quadriceps to hamstring muscle strength ratios, possibly because these ratios might change the distribution of the contact forces across the joint, not the resultant forces.

Prediction of ground reaction forces and moments during sports-related movements

When performing inverse dynamic analysis (IDA) of musculoskeletal models to study human motion, inaccuracies in experimental input data and a mismatch between the model and subject lead to dynamic inconsistency. By predicting the ground reaction forces and moments (GRF&Ms) this inconsistency can be reduced and force plate measurements become unnecessary. In this study, a method for predicting GRF&Ms was validated for an array of sports-related movements. The method was applied to ten healthy subjects performing, for example, running, a side-cut manoeuvre, and vertical jump. Pearson’s correlation coefficient ( $r$ ) and root-mean-square deviation were used to compare the predicted GRF&Ms and associated joint kinetics to the traditional IDA approach, where the GRF&Ms were measured using force plates. The main findings were that the method provided estimates comparable to traditional IDA across all movements for vertical GRFs ( $r$ ranging from 0.97 to 0.99, median 0.99), joint flexion moments ( $r$ ranging from 0.79 to 0.98, median 0.93), and resultant joint reaction forces ( $r$ ranging from 0.78 to 0.99, median 0.97). Considering these results, this method can be used instead of force plate measurements, hereby, facilitating IDA in sports science research and enabling complete IDA using motion analysis systems that do not incorporate force plate data.

Spring Ligament Tear Decreases the Ankle and Talonavicular Joint Reaction Forces

Category: Other Introduction/Purpose: Spring ligament tear is often noted in advanced stages of the adult acquired flatfoot deformity (AAFD). Previous anatomic studies demonstrated that the spring and deltoid ligaments are not separate structure, but form a confluent ligament in which the tibiocalcaneonavicular ligament (TCNL) comprises the largest component. A biomechanical study which utilized stage IIB AAFD model demonstrated inferior result of the anatomic spring ligament reconstruction compared to the tibionavicular ligament reconstruction. Therefore, the TCNL reconstruction has been proposed for effective restoration of the ankle and talonavicular joints stability in AAFD with a large spring ligament tear. We aimed to investigate if spring ligament tear of greater than 1.5 cm decreases the ankle and talonavicular joint reaction forces (JRF), and if they could be restored by the TCNL reconstruction. Methods: Ten fresh-frozen human cadaveric lower legs were obtained and disarticulated at the knee joint. Steinmann pins were percutaneously placed across the distal tibia, center of the talus and navicular while preserving adjacent soft tissues. A distraction force was applied across the ankle and talonavicular joints to determine the baseline force displacement curve to generate a best- fit polynomial equation to determine normal JRF. A spring ligament injury model was created by releasing the medial capsuloligamentous complex of the talonavicular joint and extending the resection 1.5 cm proximally. The TCNL reconstruction was performed with a forked semitendinosus allograft. The folded portion of the graft was fixed to the medial malleolar inter- colliculus. One limb of the separated part of the allograft was fixed to the navicular tuberosity and the other limb was fixed to the calcaneus below the sustentaculum tali. The resultant JRFs across the tibiotalar and talonavicular joints were measured after each step. Results: The mean baseline JRFs of the ankle and talonavicular joints were 8.36 N +/- 1.8 N and 3.01 N +/- 0.9 N, respectively. The spring ligament tear resulted in 29% decrease in tibiotalar JRF (5.97 N +/- 1.1 N, p< 0.05) and 13% decrease in talonavicular JRF (2.63 N +/- 0.8 N, p>0.05). Although the tibionavicular ligament reconstruction partially restored JRFs of the tibiotalar (7.83 +/- 2.4 N, p> 0.05) and talonavicular joints (4.08 N +/- 1.8 N, p> 0.05), they were not statistically significant. Addition of the tibiocalcaneal ligament reconstruction resulted in significantly increased JRFs of the tibiotalar (9.17 +/- 3.93 N, p> 0.05) and talonavicular joints (4.35 +/- 2.04 N, p> 0.05) compared to the spring ligament injury model. Conclusion: This is the first biomechanical study to demonstrate that a large size (>1.5 cm) spring ligament tear results in decreased JRF of the ankle joint. The decreased ankle and talonavicular JRFs were effectively restored by the novel TCNL reconstruction. This technique utilizes a forked allograft with two limbs for the tibionavicular and tibiocalcaneal ligaments reconstructions. Advanced AAFD with a large size spring ligament tear may have medial ankle instability that should not be overlooked. The novel TCNL reconstruction should be considered to prevent progression of valgus deformity. The biomechanical and clinical efficacies of the TCNL reconstruction warrant further investigation.

Hip joint geometry effects on cartilage contact stresses during a gait cycle.

The cartilage surface geometry of natural human hip joint is commonly regarded as sphere. It has been widely applied in computational simulation and hip joint prosthesis design. Some new geometry models have been developed and the sphere assumption has been questioned recently. The objective of this study was to analyze joint geometry effects on cartilage contact stress distribution and investigate contact patterns during a whole gait cycle. Hip surface was reconstructed from CT data of a healthy volunteer. Three finite element (FE) models of hip joint were developed from different cartilage geometries: natural geometry, sphere and rotational ellipsoid. Loads at ten instants of gait cycle were applied to these models based on published in-vivo data. FE predictions of peak contact pressure during gait of natural hip were compared with sphere and rotational ellipsoid replaced hip joint. Contact occurs mainly in upper anterior region of both acetabulum and femur distributing along sagittal plane of human body. It moves towards inferolateral aspect as the resultant joint reaction force changes during walking for natural hip. Peak pressures at the instant with maximum contact force were 7.48 MPa, 14.97 MPa and 13.12 MPa for models with natural hip surface, sphere replaced and rotational ellipsoid replaced surface respectively. During the whole gait cycle, contact pressure of natural hip ranked lowest in most of the instants, followed by rotational ellipsoid replaced and sphere replaced hip. The results indicate that rotational ellipsoid is more consistent with natural hip cartilage geometry than sphere during normal walking. This means rotational ellipsoid prosthesis could give a better description of physiological structure compared with standard sphere prosthesis. Therefore, rotational ellipsoid would be a better choice for prosthesis design.

The effect of glenosphere diameter and eccentricity on deltoid power in reverse shoulder arthroplasty.

The eccentric glenosphere was principally introduced into reverse shoulder arthroplasty to reduce the incidence of scapular notching. There is only limited information about the influence of its design on deltoid power and joint reaction forces. The aim of our study was to investigate how the diameter and eccentricity of the glenosphere affect the biomechanics of the deltoid and the resultant joint reaction forces. Different sizes of glenosphere and eccentricity were serially tested in ten cadaveric shoulders using a custom shoulder movement simulator. Increasing the diameter of the glenosphere alone did not alter the deltoid moment arm. However, using an eccentric glenosphere increased the moment arm of the deltoid, lowered the joint reaction force and required less deltoid force to generate movement. Eccentricity is an independent variable which increases deltoid efficiency and lowers joint reaction forces in a reverse shoulder arthroplasty. Cite this article: Bone Joint J 2016;98-B:218-23.

Determination of joint reactions in a rigid multibody system, two different approaches

In this paper two different methods for determination of frictionless joint reaction forces and moments are presented. The considered multibody system has an open kinematic chain structure. The first method refers to the determination of resultant joint reaction forces and moments based on the Rodrigues approach suitable for computation in a symbolic form. The second method presented is the method based on the so-called vectors of the body mass moments and vector rotators coupled for a pole and oriented axes. Both approaches are presented and discussed on the three- like rigid multibody system.