Effect of Stem Design and Positioning on the Leg Axis after Total Hip Arthroplasty: A Secondary Analysis.

Various parameters, like femoral offset and leg length, are associated with good patient outcomes after total hip arthroplasty. In this prospective study, the effects of stem design, its placement in the proximal femur and the resulting femoral offset on the total leg axis were investigated. The 27 patients included in this study received biplanar radiography (EOS, EOS Imaging) with 3D reconstruction using sterEOS both preoperatively and postoperatively.

Relevance of instrumented gait analysis in the prediction of the rebound phenomenon after guided growth intervention.

Predictors of rebound after correction of coronal plane deformities using temporary hemiepiphysiodesis (TH) are not well defined. The following research questions were tested: (1) Is the dynamic knee joint load useful to improve rebound prediction accuracy? (2) Does a large initial deformity play a critical role in rebound development? (3) Are BMI and a young age risk factors for rebound? Fifty children and adolescents with idiopathic knee valgus malalignment were included. A deviation of the mechanical femorotibial angle (MFA) of ≥ 3° into valgus between explantation and the one-year follow-up period was chosen to classify a rebound.

[An update on clinical gait analysis : Current developments and applications].

The objective acquisition and assessment of joint movements and loads using instrumented gait analysis has become an established tool in clinical diagnostics. In particular, marker-based 3D gait analyses make use of an increasingly comprehensive database for the assessment of orthopaedic or neurological questions. Based on this data and medical-scientific experience, increasingly reliable approaches and evaluation strategies are emerging, which also draw on methods from artificial intelligence and musculoskeletal modelling.

Influence of tension-band plates on the mechanical loading of the femoral growth plate during guided growth due to coronal plane deformities.

Correction of knee malalignment by guided growth using a tension-band plate is a common therapy to prevent knee osteoarthritis among other things. This approach is based on the Hueter-Volkmann law stating that the length growth of bones is inhibited by compression and stimulated by tension. How the locally varying mechanical loading of the growth plate is influenced by the implant has not yet been investigated.

Lower limb joint loading in patients with unilateral hip osteoarthritis during bipedal stance and the effect of total hip replacement.

Osteoarthritis of the hip is a common condition that affects older adults. Total hip replacement is the end-stage treatment to relief pain and improve joint function. Little is known about the mechanical load distribution during the activity of bipedal stance, which is an important daily activity for older adults who need to rest more frequently.

Peak knee joint moments accurately predict medial and lateral knee contact forces in patients with valgus malalignment.

Compressive knee joint contact force during walking is thought to be related to initiation and progression of knee osteoarthritis. However, joint loading is often evaluated with surrogate measures, like the external knee adduction moment, due to the complexity of computing joint contact forces. Statistical models have shown promising correlations between medial knee joint contact forces and knee adduction moments in particularly in individuals with knee osteoarthritis or after total knee replacements (R = 0.

Influence of implantation of a total hip endoprosthesis on the ipsilateral leg alignment: the effect of sex and dysplasia of the hip.

Introduction: Differences in leg and hip morphology exist between sexes and developmental hip dysplasia is known to alter proximal femoral morphology. The purpose of this study was to determine whether existing differences in leg alignment due to sex or developmental hip dysplasia have an effect on changes in leg alignment after total hip arthroplasty.

Materials And Methods: 30 hip osteoarthritis patients underwent biplanar full-length radiography in the standing position preoperatively and 3 months after total hip arthroplasty.

Comparison of Gait Symmetry and Joint Moments in Unilateral and Bilateral Hip Osteoarthritis Patients and Healthy Controls.

Patients with unilateral hip osteoarthritis show a characteristic gait pattern in which they unload the affected leg and overload the unaffected leg. Information on the gait characteristics of patients with bilateral hip osteoarthritis is very limited. The main purposes of this study were to investigate whether the gait pattern of both legs of patients with bilateral hip osteoarthritis deviates from healthy controls and whether bilateral hip osteoarthritis patients show a more symmetrical joint load compared to unilateral hip osteoarthritis patients.

Identification of Patients with Similar Gait Compensating Strategies Due to Unilateral Hip Osteoarthritis and the Effect of Total Hip Replacement: A Secondary Analysis.

Despite good clinical functional outcome, deficits in gait biomechanics exist 2 years after total hip replacement surgery. The aims of this research were (1) to group patients showing similar gait adaptations to hip osteoarthritis and (2) to investigate the effect of the surgical treatment on gait kinematics and external joint moments. In a secondary analysis, gait data of 51 patients with unilateral hip osteoarthritis were analyzed.

Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading.

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements.

Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces.

Accuracy of Preoperative Templating in Total Hip Arthroplasty With Special Focus on Stem Morphology: A Randomized Comparison Between Common Digital and Three-Dimensional Planning Using Biplanar Radiographs.

Background: Accurate preoperative planning is a key component of successful total hip arthroplasty (THA). The purpose of the present study was to compare the accuracy and reliability of three-dimensional (hipEOS) and common digital two-dimensional (TraumaCad) templating with special focus on stem morphology.

Methods: 51 patients undergoing THA were randomized to two groups.

Knee Load Distribution in Hip Osteoarthritis Patients After Total Hip Replacement.

Reduced external knee adduction moments in the second half of stance after total hip replacement have been reported in hip osteoarthritis patients. This reduction is thought to shift the load from the medial to the lateral knee compartment and as such increase the risk for knee osteoarthritis. The knee adduction moment is a surrogate for the load distribution between the medial and lateral compartments of the knee and not a valid measure for the tibiofemoral contact forces which are the result of externally applied forces and muscle forces.

Validity of and recommendations for knee joint acoustic assessments during different movement conditions.

Knee joint sounds contain information on joint health, morphology and loading. These acoustic signals may be elicited by further, as yet unknown factors. By assessing potential elicitors and their relative contributions to the acoustic signal, we investigated the validity of vibroarthrographic assessments during different movement conditions with the aim to derive recommendations for their practical usage.

Non-invasive determination of frontal plane lower limb alignment using motion capture technique - An alternative for full-length radiographs in young patients treated by a temporary hemiepiphysiodesis?

Background: Multiple full-length standing anteroposterior radiographs are common practice to quantify the mechanical axis angle (MAA) in young patients with lower limb malalignment in the frontal plane treated with a temporary hemiepiphysiodesis.

Research Question: Is it possible to predict the MAA measured with gold-standard radiographs from a non-invasive method using the marker-based motion capture technique in a standing position and has an increased body mass index (BMI) a negative effect on this prediction?

Methods: Forty-six children and adolescents with valgus or varus malalignment of the knee were measured several times during the treatment period. In total 175 data sets were evaluated in this prospective study.

Effect of guided growth intervention on static leg alignment and dynamic knee contact forces during gait.

Background: Lower limb malalignment in the frontal plane is one of the major causes of developing knee osteoarthritis. Growing children can be treated by temporary hemiepiphysiodesis when diagnosed with lower limb malalignment.

Research Question: Is there a difference between medial or lateral knee contact force (KCF) before (PRE) and after (POST) hemiepiphysiodesis in patients with valgus malalignment and compared to a typically developed control group (TD)? Does a linear relationship exist between the static radiographic mechanical axis angle and dynamic medial/lateral KCF?

Methods: In this prospective study, an OpenSim full body model with an adapted knee joint was used to calculate KCFs in the stance phase of 16 children with diagnosed genu valgum and 16 age- and sex-matched TDs.

Muscle Activity of the Latissimus Dorsi after Tendon Transfer in Patients with Rotator Cuff Tears.

: Massive irreparable posterosuperior rotator cuff tears may result in the loss of external rotation. Most of the patients with posterosuperior rotator cuff tears suffer from a restriction in their daily life actions. Latissimus dorsi tendon transfer (LDTT) is a method to restore abduction and external rotation in these patients.

Effect of total joint replacement in hip osteoarthritis on serum COMP and its correlation with mechanical-functional parameters of gait analysis.

Objective: To study the effect of total hip replacement (THR) on serum cartilage oligomeric matrix protein concentration (sCOMP) and its correlation with joint loading during gait in patients with unilateral hip osteoarthritis.

Design: In this prospective multimodal (clinical, biomechanical, biochemical) study blood samples from 15 patients were taken before and up to three times after THR (7 days, 3 months and 1 year), each after a resting period of at least 30 min, for analysis of sCOMP. Gait analysis was performed before and 1 year after THR to determine hip and knee joint moments.

3D motion analysis of latissimus dorsi tendon transfer in patients with posterosuperior rotator cuff tears: Analysis of proprioception and the ability to perform ADLS.

Background: Massive irreparable posterosuperior rotator cuff tears may result in a loss of external rotation. Most of these patients lose their ability to perform activities of daily living (ADLs), especially where external rotation and abduction are needed. Latissimus dorsi tendon transfer (LDTT) is a method to restore abduction and external rotation in patients with posterosuperior rotator cuff tears.

Are changes in radiological leg alignment and femoral parameters after total hip replacement responsible for joint loading during gait?

Background: Gait kinematics after total hip replacement only partly explain the differences in the joint moments in the frontal plane between hip osteoarthritis patients after hip replacement and healthy controls. The goal of this study was to determine if total hip replacement surgery affects radiological leg alignment (Hip-Knee-Shaft-Angle, femoral offset, Neck-Shaft-Angle and varus/valgus alignment) and which of these parameters can explain the joint moments, additionally to the gait kinematics.

Methods: 22 unilateral hip osteoarthritis patients who were scheduled for total hip replacement were included in the study.

German Society of Biomechanics (DGfB) Young Investigator Award 2019: Proof-of-Concept of a Novel Knee Joint Simulator Allowing Rapid Motions at Physiological Muscle and Ground Reaction Forces.

The determination of realistic loads acting in knee ligaments, articular cartilage, menisci and their attachments during daily activities require the creation of physiological muscle forces, ground reaction force and unconstrained kinematics. However, no test setup is currently available that is able to simulate such physiological loads during squatting and jump landing exercises. Therefore, a novel knee joint simulator allowing such physiological loads in combination with realistic, rapid movements is presented.

Influence of Hip Geometry Reconstruction on Frontal Plane Hip and Knee Joint Moments During Walking Following Primary Total Hip Replacement.

Background: Following total hip replacement (THR), hip geometry reconstruction parameters such as the femoral offset (FO) correlate with hip stability and wear. The purpose of this study is to determine the relationship between hip geometry parameters and knee and hip joint loading during walking.

Methods: Forty-one patients were examined before and a minimum of 1 year after primary THR.

Long-term muscle changes after hamstring lengthening in children with bilateral cerebral palsy.

Aim: To evaluate short-term (1y postoperatively; E1) and long-term (at least 4y postoperatively; E2) changes in hamstring muscle-tendon length (MTL) and lengthening velocity after hamstring lengthening in children with bilateral cerebral palsy (CP).

Method: Three-dimensional gait analysis was performed in 19 children (16 males, 3 females; 36 limbs; mean age at surgery 9y [SD 3y]; range 6-10y) with flexed knee gait, preoperative ankle dorsiflexion lower than 20 degrees, and CP before bilateral hamstring lengthening (E0), at E1 and E2. Hamstring MTL (normalized by leg length) and velocity were assessed via OpenSim software.

Abnormal loading of the hip and knee joints in unilateral hip osteoarthritis persists two years after total hip replacement.

A total hip replacement (THR) is a common and routine procedure to reduce pain and restore normal activity. Gait analysis can provide insights into functional characteristics and dynamic joint loading situation not identifiable by clinical examination or static radiographic measures. The present prospective longitudinal study tested whether 2 years after surgery a THR would restore dynamic loading of the knee and hip joints in the frontal plane to normal.

Mid-term development of hamstring tendon length and velocity after distal femoral extension osteotomy in children with bilateral cerebral palsy: a retrospective cohort study.

Aim: Flexed knee gait can be treated with distal femoral extension osteotomy (DFEO) and additional patellar tendon advancement (PTA) in children with cerebral palsy (CP). This study assesses changes in hamstring muscle tendon length (MTL) and velocity after DFEO (+PTA).

Method: Nineteen children (mean age 13y [standard deviation 3y] at surgery) with CP and flexed knee gait who were treated with DFEO (15 limbs) or DFEO+PTA (10 limbs) were retrospectively included in this study.

Knee-ankle-foot orthosis with powered knee for support in the elderly.

A prototype of a powered knee orthotic device was developed to determine whether fractional external torque and power support to the knee relieves the biomechanical loads and reduces the muscular demand for a subject performing sit-to-stand movements. With this demonstrator, consisting of the subsystems actuation, kinematics, sensors, and control, all relevant sensor data can be acquired and full control is maintained over actuator parameters. A series-elastic actuator based on a direct current motor provides up to 30 Nm torque to the knee via a hinge joint with an additional sliding degree of freedom.