Felix Stief

Effect of compensatory trunk movements on knee and hip joint loading during gait in children with different orthopedic pathologies

Ipsilateral trunk lean toward the affected stance limb has been identified as a compensatory mechanism to unload the hip joint. However, this altered gait pattern increases the lever arm around the knee joint by shifting the ground reaction vector more lateral to the knee joint center, which could be sufficient to deform the lateral compartment of the knee. The purpose of the present study was to show the effect of ipsilateral trunk lean on hip and knee joint moments in the frontal plane in 132 young patients with different orthopedic diagnosis. Linear correlations between ipsilateral trunk lean and the external knee and/or hip adduction moment were detected for patients with Legg-Calvé-Perthes disease (LCPD), arthrogryposis multiplex congenita, myelomeningocele, and unilateral cerebral palsy (CP). In contrast, children with bilateral CP did not show such a relationship due to an increased internal foot placement. In comparison to the hip joint, the effect of ipsilateral trunk lean in patients with LCPD is obviously more pronounced in the knee joint. The valgus thrust of the knee could initiate degenerative changes by placing altered loads on regions of the articular cartilage that were previously conditioned for different load levels. The results suggest that the ipsilateral trunk lean should not be considered and recommended as unloading mechanism for the hip joint on its own but also as a potential increased joint loading of the lateral knee compartment. Therefore, an acceptable therapy concept for limping patients should aim for an inconspicuous gait pattern with a reduced trunk movement.

Has a Mono- or Bisegmental Lumbar Spinal Fusion Surgery an Influence on Self-Assessed Quality of Life, Trunk Range of Motion, and Gait Performance?

Study Design. This investigation prospectively compared self-assessed quality of life and biomechanical measures of physical function before and after spinal fusion surgery in 26 adult patients with symptomatic lumbar degenerative disease. Objective. The objective was to demonstrate that (1) due to a reduction of low back pain, quality of life as well as gait parameters would improve after a spinal fusion surgery and (2) gait performance is more similar to that observed in healthy controls at the same age, whereas trunk range of motion remains unchanged after surgery. Summary of Background Data. Current outcome evaluations of spinal fusion surgery are based on radiological changes and self-report questionnaires. However, these traditional measures do not sufficiently assess the functionality. Methods. Twenty-six patients with a mean age of 59.3 (SD: 10.1) years and 20 healthy subjects at the same age were evaluated. Before and approximately 6 months after a mono- or bisegmental spinal fusion surgery, patients completed self-report questionnaires and biomechanical assessments of gait analysis and trunk range of motion in the 3 principal planes of the body. Results. Results indicated an improvement in quality of life as well as an increased pain-free walking distance, walking speed, step length, and maximum hip extension during the stance phase of gait. Anterior pelvis and thorax tilt were significantly reduced after the surgery without significant differences compared with the control group. Regarding the trunk range of motion, we observed a decrease in maximum forward flexion and an increase in the fingertip-floor distance after surgery. Conclusion. The study results show that lumbar spinal fusion is a useful procedure to improve patients quality of life and gait performance. Although we performed only mono- and 2-level fusions, the sagittal alignment of the pelvis and thorax during walking was normalized. Clinical gait analysis contributes to the advancement of our knowledge regarding the functional changes after a spinal fusion surgery. Level of Evidence: 2

Effect of lower limb malalignment in the frontal plane on transverse plane mechanics during gait in young individuals with varus knee alignment

BACKGROUND Varus knee alignment has been identified as a risk factor for the progression of medial knee osteoarthritis (OA). This study tested the hypothesis that not only frontal plane kinematics and kinetics but also transverse plane lower extremity mechanics during gait are affected by varus malalignment of the knee. METHODS Eighteen, otherwise healthy children and adolescents with varus malalignment of the knee were studied to examine the association between static varus malalignment and functional gait parameters. Kinematic data were collected using a Vicon motion capture system (Vicon Motion Systems, Oxford, UK). Two AMTI force plates (Advanced Mechanical Technology, Inc., Watertown, MA, USA) were used to collect kinetic data. RESULTS The results indicated that changes in transverse plane mechanics occur concomitantly with changes in knee malalignment in the frontal plane. A mechanical consequence of varus knee malalignment is obviously an increased endorotation of the foot (internal foot placement) and an increased internal knee rotation (tibia rotation) during stance phase. The linear correlation between the maximum external knee adduction moment in terminal stance and the internal knee rotation in terminal stance (r=0.823, p<0.001) shows that this transverse plane gait mechanics is directly in conjunction with intrinsic compressive load on the medial compartment during gait. CONCLUSIONS Understanding factors that influence dynamic knee joint loading in healthy, varus malaligned knees may help us to identify risk factors that lead to OA. Thus, three-dimensional gait analysis could be used for clinical prognoses regarding the onset or progression of medial knee OA.

Predictors of pelvic retraction in children with cerebral palsy derived from gait parameters and clinical testing

Excessive pelvic rotation in the transverse plane is common in patients with cerebral palsy. Knowing the underlying reasons is important for clinical decision making, since changes in pelvic retraction might have an effect on internally rotated gait. We hypothesized that the contralateral leg contributes considerably to pelvic rotation on the retracted side. Therefore the aim of this study is to calculate predictors for pelvic retraction using both, parameters from the retracted and from the contralateral protracted side. Thirty-two children with diplegia and 18 children with hemiplegia were examined by three-dimensional gait analysis followed by a clinical examination protocol. Stepwise multilinear regression of the response value mean pelvic retraction during stance phase was performed on 10 potential predictors of dynamic gait data and 10 corresponding predictors of clinical data of the retracted and the contralateral protracted side. Gait analysis revealed ankle push-off energy on the protracted side as the best predictors in hemiplegic patients explaining 59% of the variance in pelvic retraction. In diplegic patients external hip rotation of the protracted side was most accurate in predicting pelvic retraction (27%). Best clinical predictors for hemiplegic patients were ankle dorsiflexion on the retracted side (46%) and for diplegic patients it was the knee extension strength on the protracted side together with hip rotation on the retracted side (36%). In hemiplegic patients ankle push-off energy of the contralateral side is a significant compensation mechanism that might cause increased pelvic retraction to compensate for the weakness of the involved side. In diplegic patients prediction of pelvic retraction was only moderate and requires further investigation.

Unilateral hip osteoarthritis: The effect of compensation strategies and anatomic measurements on frontal plane joint loading†

In order to reduce pain caused by the affected hip joint, unilateral hip osteoarthritis patients (HOAP) adopt characteristic gait patterns. However, it is unknown if the knee and hip joint loading in the non‐affected (limbnon‐affected) and the affected (limbaffected) limb differ from healthy controls (HC) and which gait parameters correlate with potential abnormal joint loading. Instrumented 3D‐gait analysis was performed on 18 HOAP and 18 sex, age, and height matched HC. The limbnon‐affected showed greater first and second peak external hip adduction moments (first HAM: +15%, p = 0.014; second HAM: +15%, p = 0.021, respectively), than seen in HC. In contrast, the second peak external knee adduction moment (KAM) in the limbaffected is reduced by about 23% and 30% compared to the limbnon‐affected and HC, respectively. Furthermore, our patients showed characteristic gait compensation strategies including reduced peak vertical forces (pvF), a greater foot progression angle (FPA), and reduced knee range of motion (ROM) in the limbaffected. The limbaffected was 5.6 ± 3.8 mm shorter than the limbnon‐affected. Results of stepwise regression analyses showed that increased first pvF explain 16% of first HAM alterations, whereas knee ROM and FPA explain 39% of second KAM alterations. We therefore expect an increased rate of progression of OA in the hip joint of the limbnon‐affected and suggest that the shift in the medial‐to‐lateral knee joint load distribution may impact the rate of progression of OA in the limbaffected. The level of evidence is III.

Influence of the Lower Jaw Position on the Running Pattern.

Introduction The effects of manipulated dental occlusion on body posture has been investigated quite often and discussed controversially in the literature. Far less attention has been paid to the influence of dental occlusion position on human movement. If human movement was analysed, it was mostly while walking and not while running. This study was therefore designed to identify the effect of lower jaw positions on running behaviour according to different dental occlusion positions. Methods Twenty healthy young recreational runners (mean age = 33.9±5.8 years) participated in this study. Kinematic data were collected using an eight-camera Vicon motion capture system (VICON Motion Systems, Oxford, UK). Subjects were consecutively prepared with four different dental occlusion conditions in random order and performed five running trials per test condition on a level walkway with their preferred running shoes. Vector based pattern recognition methods, in particular cluster analysis and support vector machines (SVM) were used for movement pattern identification. Results Subjects exhibited unique movement patterns leading to 18 clusters for the 20 subjects. No overall classification of the splint condition could be observed. Within individual subjects different running patterns could be identified for the four splint conditions. The splint conditions lead to a more symmetrical running pattern than the control condition. Discussion The influence of an occlusal splint on running pattern can be confirmed in this study. Wearing a splint increases the symmetry of the running pattern. A more symmetrical running pattern might help to reduce the risk of injuries or help in performance. The change of the movement pattern between the neutral condition and any of the three splint conditions was significant within subjects but not across subjects. Therefore the dental splint has a measureable influence on the running pattern of subjects, however subjects individuality has to be considered when choosing the optimal splint condition for a specific subject.

Correction of static axial alignment in children with knee varus or valgus deformities through guided growth: Does it also correct dynamic frontal plane moments during walking?

Malaligned knees are predisposed to the development and progression of unicompartmental degenerations because of the excessive load placed on one side of the knee. Therefore, guided growth in skeletally immature patients is recommended. Indication for correction of varus/valgus deformities are based on static weight bearing radiographs. However, the dynamic knee abduction moment during walking showed only a weak correlation to malalignment determined by static radiographs. Therefore, the aim of the study was to measure the effects of guided growth on the normalization of frontal plane knee joint moments during walking. 15 legs of 8 patients (11-15 years) with idiopathic axial varus or valgus malalignment were analyzed. 16 typically developed peers served as controls. Instrumented gait analysis and clinical assessment were performed the day before implantation and explantation of eight-plates. Correlation between static mechanical tibiofemoral axis angle (MAA) and dynamic frontal plane knee joint moments and their change by guided growth were performed. The changes in dynamic knee moment in the frontal plane following guided growth showed high and significant correlation to the changes in static MAA (R=0.97, p<0.001). Contrary to the correlation of the changes, there was no correlation between static and dynamic measures in both sessions. In consequence two patients that had a natural knee moment before treatment showed a more pathological one after treatment. In conclusion, the changes in the dynamic load situation during walking can be predicted from the changes in static alignment. If pre-surgical gait analysis reveals a natural load situation, despite a static varus or valgus deformity, the intervention must be critically discussed.

Unilateral hip osteoarthritis: Its effects on preoperative lower limb muscle activation and intramuscular coordination patterns

The objective of this study was to test if patients with unilateral hip osteoarthritis (OA) show greater muscle activity asymmetry between their affected and non-affected limbs than healthy controls between their left and right limbs. Seventeen patients with unilateral hip OA (7 females, 10 males) and 17 age-matched healthy controls (7 females, 10 males) participated in this study. Both groups performed instrumented gait analysis at comparable speeds. Muscle activity was recorded simultaneously for the tibialis anterior (TA), gastrocnemius medialis (GM), vastus lateralis (VL), semitendinosus (ST), tensor fasciae latae (TFL), and gluteus medius (GLM) muscles. In hip OA patients, EMG data showed greater activity of the TA muscle in the non-affected limb, and greater TFL muscle activity in the affected limb. Compared to healthy controls, greater asymmetries between paired limbs were observed for the TA and GM muscles. Finally, the TFL muscle of the affected limb contributed more to the total limb muscle activity than did the non-affected limb. The observed alterations in TA and GM muscle activity in hip OA patients may be due to the greater peak braking and peak vertical forces measured in the non-affected limb. Contrary to this, greater TLF muscle activity of the affected limb indicates the demands put on stabilizing the hip during stance phase. Further studies are necessary to test whether leg length discrepancy affects muscle activation alterations between the affected and non-affected limb in unilateral hip OA patients.

Differences in Gait Performance, Quadriceps Strength, and Physical Activity Between Fallers and Nonfallers in Women with Osteoporosis

The present study should reveal differences in gait performance, quadriceps strength, and physical activity (PA) between fallers and nonfallers in women with osteoporosis. Forty-one women with osteoporosis (17 fallers, 24 nonfallers) participated. Gait analysis shows that fallers were walking with a slower walking speed (-9%, p = .033) and had a shorter stride length (-7%, p = .039). Moreover, fallers showed a decreased ankle power generation (-18%, p = .045). The quadriceps strength was decreased by 24% for fallers (p = .005) while PA showed no significant differences. Although a decrease in ankle power generation could have an effect on floor clearance for limb advancement in the swing phase, the causal relationship between spatiotemporal parameters (walking speed, stride length) and walking ankle joint power generation remains unknown and warrants further investigation. In conclusion, walking speed, stride length, ankle power generation, and quadriceps strength can be used to differentiate between fallers and nonfallers in women with osteoporosis.

Abnormal loading of the hip and knee joints in unilateral hip osteoarthritis persists two years after total hip replacement: JOINT LOADING AFTER 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. Instrumented gait analysis was performed shortly before surgery and approximately 2 years after THR on 15 unilateral hip osteoarthritis (OA) patients. 15 asymptomatic matched individuals were recruited as healthy controls. Results showed that abnormal joint loading persisted 2 years after THR. The 2nd external knee adduction moment in terminal stance in the affected (−34%, p = 0.002, d = 1.22) and non‐affected limb (−25%, p = 0.035, d = 0.81) was lower compared to controls and thus indicated a shift in the knee joint load distribution from medial to lateral. A correlation analysis revealed that a smaller hip range of motion explained 46% of 2nd knee adduction moment alterations. In contrast, the 2nd external hip adduction moment in terminal stance was postoperatively higher in the affected (+22%, p = 0.007, d = 1.04) and non‐affected limb (+22%, p = 0.005, d = 1.05). Here, 51% of 2nd hip adduction moment alterations can be explained with a greater hip adduction angle. Patients with a THR may therefore be at higher risk for abnormal joint loading and thus for the development of OA in other joints of the lower extremities.