Slipped Capital Femoral Epiphysis (SCFE) is one of the most common hip disorders in children and is characterized by a proximal femoral deformity, resulting in early osteoarthritis. Several studies have suggested that SCFE patients after in situ fixation show an altered gait pattern. Early identification of gait alterations might lead to earlier intervention programs to prevent osteoarthritis. The aim of this study is to analyse gait alterations in SCFE patients after in situ fixation compared to typically developed children, using the Computer Assisted Rehabilitation Environment (CAREN) system. This is a cross-sectional, multi-center case-control study in the Netherlands. Eight SCFE patients and eight age- and sex-matched typically developed were included from two hospitals. Primary outcomes were kinematic parameters (absolute joint angles), studied with gait analysis using statistical parametric mapping (SPM). Secondary outcomes were spatiotemporal parameters, the Notzli alpha angle, muscle activation patterns (EMG), and clinical questionnaires (VAS, Borg CR10, SF-36, and HOOS), analyzed using non-parametric statistical methods.Introduction and Objective
Materials and Methods
Osteoarthritis is one of the major causes of immobility. Most commonly, osteoarthritis manifests at the knee joint. Prevalence of knee osteoarthritis (KNOA) increases with age. Another important risk factor for KNOA is obesity. Research has shown that obese subjects have almost four times the risk of developing KNOA, which may be explained by both an increased knee loading. In medial compartment KNOA, the knee adduction moment (KAM) during gait is considered a marker for disease severity. KAM is dependent of the magnitude of the ground reaction force and its moment arm relative to the knee joint centre. In addition, obesity has been reported to augment KAM during gait. However, after removal of the direct contributions of body weight, KAM parameters may be different due to obesity-related gait adaptations to limit knee loading. While KAM has been thoroughly investigated during gait, little is known about KAM during stair negotiation, during which knee loads are higher compared to gait. The aim of the current study is therefore to compare normalized KAM during the stance phase of stair negotiation between lean KNOA patients, obese KNOA patients, and healthy controls. This case control study included 20 lean controls, 14 lean KNOA patients, and 16 obese KNOA patients. All subjects ascended and descended a two-step staircase at a self-selected, comfortable speed. Radiographic imaging and MRI were used to evaluate knee cartilage and KNOA status. Motion analysis was performed with a three-dimensional motion capture system. Kinetic data were obtained by one force platform. The parameters of study included: stance phase duration, toe-out angle, KAM peaks and KAM impulse. During stair ascent obese KNOA patients showed a longer stance phase than healthy controls (P 0.050). Despite high between-subject variability, KAM impulse was found 45% higher in the obese KNOA group during stair descent, when compared to healthy controls (P =0.012). The absence of a significant effect of groups on the normalized KAM during stair negotiation may be explained by a lower ambulatory speed in the obese KNOA group, that effectively lowers GRFz. Decreasing ambulatory speed may be an effective strategy to lower KAM during stair negotiation.
3D measurement of joint angles so far has only been possible using marker-based movement analysis, and therefore has not been applied in (larger scale) clinical practice (performance test) and even less so in the free field (activity monitoring). 3D joint angles could provide useful additional information in assessing the risk of anterior cruciate ligament injury using a vertical drop jump or in assessing knee range of motion after total knee arthroplasty. We developed a tool to measure dynamic 3D joint angles using 6 inertial sensors, attached to left and right shank, thigh and pelvis. The same sensors have been used for activity identification in a previous study. To validate the setup in a pilot study, we measured 3D knee and hip angles using the sensors and a Vicon movement lab simultaneously in 3 subjects. Subjects performed drop jumps, squats and ran on the spot. The mean error between Vicon and sensor measurement for the maximum joint angles was 3, 7 and 8 degrees for knee flexion, ad/abduction and rotation respectively, and 9, 7 and 10 degrees for hip flexion, ad/abduction and rotation respectively. No calibration movements were required. A major part of the inaccuracy was caused by soft tissue effects and can partly be resolved by improved sensor attachment. These pilot results show that it is feasible to measure 3D joint angles continuously using unobtrusive light-weight sensors. No movement lab is necessary and therefore the measurements can be done in a free field setting, e.g. at home or during training at a sport club. A more extensive validation study will be performed in the near future.
Osteoarthritis of the first metatarsophalangeal (MTP1) joint is a common disorder in elderly, resulting in pain and disability. Arthrodesis of this joint shows satisfactory results, with relieve of pain in approximately 85% of the patients. However, the compensation mechanism for loss of motion in the MTP1 joint after MTP1 arthrodesis is unknown. A reduced compensation mechanism of the foot may explain the disappointing result of MTP1 arthrodesis in the remaining 15% of the patients. This study was conducted to elucidate this compensation mechanism. We hypothesize that the ankle and forefoot are responsible for compensation after MTP1 arthrodesis. Gait was evaluated in eight patients with arthrodesis of the MTP1 joint (10 feet) and twelve healthy controls (21 feet) by using a sixteen-camera Vicon-system. The four-segmental, validated Oxford-Foot-Model was used to investigate differences in range of motion of the hindfoot-tibia, forefoot-hindfoot and hallux-forefoot segment during stance. For statistical analysis, the unpaired t-test with Bonferroni correction (p<0.0125) was performed. No differences in spatiotemporal parameters were observed between both groups. In the frontal plane, MTP1 arthrodesis decreased the range of motion in midstance, while an increased range of motion was observed in terminal stance for the hindfoot relative to the tibia in the transversal plane. Subsequently range of motion in the forefoot in preswing was increased. This resulted in less eversion in the hindfoot during midstance, increased internal rotation of the hindfoot during terminal stance and more supination in the forefoot during preswing in the MTP1 arthrodesis group. Motion of the hallux was restricted in the loading response (i.e. plantar flexion) and terminal stance (i.e. dorsiflexion). As hypothesized, both the ankle and the forefoot are responsible for compensation after MTP1 arthrodesis, because arthrodesis causes less eversion and increased internal rotation of the hindfoot and increased supination of the forefoot. As expected, both dorsiflexion and plantar flexion of the hallux was restricted due to arthrodesis. These findings suggest a gait pattern in which the lateral arch of the foot is more loaded and the stiff hallux is avoided during the stance phase of gait. Our results indicate that proper motion of the forefoot and ankle joint is important when considering arthrodesis of the MTP1 joint. Therefore, we emphasize careful assessment the range of motion in the forefoot and ankle joint in the pre-operative situation, since patients with a decreased range of motion in the forefoot and ankle joint have a less functioning compensation mechanism. We currently perform a study to evaluate the strength of the positive correlation between the pre-operative range of motion in the forefoot and ankle joint and the clinical outcome.
The quantification of T1Rho relaxation times is not related with internal loading. Improvements in modeling and imaging techniques might lead to better understanding of the pathomechanics of the knee. The onset and progression of knee osteoarthritis has been associated with an increased external knee adduction moment (EKAM). However, this external measure has no direct relationship with internal loading of the knee. For a better understanding of the pathomechanics of the knee musculoskeletal models could be used to relate external and internal knee loading. Consequently, high internal loading might cause cartilage degeneration in patients with OA. T1RhoMRI can detect changes in proteoglycan content and is therefore a non-invasive measure of cartilage degeneration in knee OA. The purpose of this study was to relate internal loading of the knee simulated by musculoskeletal models with cartilage health using T1rhoMRI.Summary
Introduction
Upper extremity activity was similar in patients and healthy subjects, showing no significant asymmetry between arms within subjects. Further improvements (e.g. thresholds, filters, inclinometer function) are needed to show the clinical value of AM for patients suffering shoulder complaints. Activity monitoring is becoming a popular outcome tool especially in orthopaedics. The suitability of a single 3D acceleration-based activity monitor (AM) for patients with lower-extremity problems has been shown. However less is known about its feasibility to monitor upper-extremity activity. Insight into the amount and intensity of upper-extremity activity of the affected and non-affected arm (asymmetry) may be of added value for diagnostics, therapy choice and evaluating treatment effects. This study investigates the feasibility of a single AM to evaluate (asymmetry in) upper-extremity activity in daily life.Summary
Introduction
A single 3D accelerometer is accurate in measuring upper-extremity activity durations, rest periods and intensities, suggesting its feasibility for daily life measurements with patients. Further enhancements are feasible to reduce residual false classifications of intensity from certain activities. Physical activity is an important outcome measure in orthopaedics as it reflects how surgically restored functional capacity is used in daily life. Accelerometer-based activity monitors (AM) are objective, reliable and valid to determine lower extremity activity in orthopaedic patients. However the suitability of a single AM to monitor upper-extremity activity, in terms of quantity and intensity, has not been investigated. This study investigates the suitability and validity of a single AM to measure quantity and intensity of upper-extremity activity.Summary
Introduction
An alternative way to assess three dimensional skin motion artefacts of kinematic models is presented and applied to a novel kinematic foot model. Largest skin motion is measured in the tarsal region. Motion capture systems are being used in daily clinical practise for gait analysis. Last decade several kinematic foot models have been presented to gain more insight in joint movement in various foot pathologies. No method is known to directly measure bone movement in a clinical setting. Current golden standard is based on measurement of motion of skin markers and translation to joint kinematics. Rigid body assumptions and skin motion artefacts can seriously influence the outcome of this approach and rigorous validation is required before clinical application is feasible. Validation of kinematic models is currently done via comparison with bone pin studies. However, these studies can only assess major bones in a highly invasive way; another problem is the non-synchronous measurement of skin markers and bone pins. Recently the Glasgow Maastricht kinematic foot model, which comprises all 26 foot segments, has been presented. To validate the model we propose a novel non-invasive method for the assessment of skin motion artefact, involving loaded CT data.Summary Statement
Introduction
