Individuals with multi-compartment knee osteoarthritis (KOA) frequently experience challenges in activities of daily living (ADL) such as stair ambulation. The Levitation “Tri-Compartment Offloader” (TCO) knee brace was designed to reduce pain in individuals with multicompartment KOA. This brace uses novel spring technology to reduce tibiofemoral and patellofemoral forces via reduced quadriceps forces. Information on brace utility during stair ambulation is limited. This study evaluated the effect of the TCO during stair descent in patients with multicompartment KOA by assessing knee flexion moments (KFM), quadriceps activity and pain. Nine participants (6 male, age 61.4±8.1 yrs; BMI 30.4±4.0 kg/m2) were tested following informed consent. Participants had medial tibiofemoral and patellofemoral OA (Kellgren-Lawrence grades two to four) diagnosed by an orthopaedic surgeon. Joint kinetics and muscle activity were evaluated during stair descent to compare three bracing conditions: 1) without brace (OFF); 2) brace in low power (LOW); and 3) brace in high power (HIGH). The brace spring engages from 60° to 120° and 15° to 120° knee flexion in LOW and HIGH, respectively. Individual brace size and fit were adjusted by a trained researcher. Participants performed three trials of step-over-step stair descent for each bracing condition. Three-dimensional kinematics were acquired using an 8-camera motion capture system. Forty-one spherical reflective markers were attached to the skin (on each leg and pelvis segment) and 8 markers on the brace. Ground reaction forces and surface EMG from the vastus medialis (VM) and vastus lateralis (VL) were collected for the braced leg. Participants rated knee pain intensity performing the task following each bracing condition on a 10cm Visual Analog Scale ranging from “no pain” (0) to “worst imaginable pain” (100). Resultant brace and knee flexion angles and KFM were analysed during stair contact for the braced leg. The brace moment was determined using brace torque-angle curves and was subtracted from the calculated KFM. Resultant moments were normalized to bodyweight and height. Peak KFMs were calculated for the loading response (Peak1) and push-off (Peak2) phases of support. EMG signals were normalized and analysed during stair contact using wavelet analysis. Signal intensities were summed across wavelets and time to determine muscle power. Results were averaged across all 3 trials for each participant. Paired T-tests were used to determine differences between bracing conditions with a Bonferroni adjustment for multiple comparisons (α=0.025). Peak KFM was significantly lower compared to OFF with the brace worn in HIGH during the push-off phase (p Table 1: Average peak knee flexion moments, quadriceps muscle power and knee pain during stair descent in 3 brace conditions (n=9). Quadriceps activity, knee flexion moments and pain were significantly reduced with TCO brace wear during stair descent in KOA patients. These findings suggest that the TCO assists the quadriceps to reduce KFM and knee pain during stair descent. This is the first biomechanical evidence to support use of the TCO to reduce pain during an ADL that produces especially high knee forces and flexion moments. For any figures or tables, please contact the authors directly.
The pathogenesis of scoliosis progression remains poorly understood. Seventy-two subject data sets, consisting of four successive values of Cobb-angle and lateral deviations at apices for six and twelve-months intervals in the coronal plane, were used to train and test an artificial neural network (ANN) to predict spinal deformity progression. The accuracies of the trained ANN (3-4-1) for training and testing data were within 3.64° (±2.58°) and 4.40° (±1.86°) of Cobb angles, and within 3.59 (±3.96) mm and 3.98 (±3.41) mm of lateral deviations, respectively. The adapted technique for predicting the scoliosis deformity progression has promising clinical applications. Scoliosis is a common and poorly understood three-dimensional spinal deformity. The study purpose is to predict scoliosis progression at six and twelve months intervals in the future using successive spinal indices with an artificial neural network (ANN). The adapted ANN technique enables earlier detection of scoliosis progression with high accuracy. Improved prediction of scoliosis progression will impact bracing or surgical treatment decisions, and may decrease hazardous X-ray exposure. Seventy-two data sets from adolescent idiopathic scoliosis subjects recruited at the Alberta Children’s Hospital were used in this study. Data sets composed of four successive values of Cobb angles and lateral deviations at apices for six and twelvemonth intervals (coronal plane) were extracted to train and test a specific ANN for predicting scoliosis progression. Progression patterns in Cobb angles (n = 10) and lateral deviations (n = 8) were successfully identified. The accuracies of the trained ANN (3-4-1) with the training and testing data sets were 3.64° (±2.58°) and 4.40° (±1.86°) of Cobb angles, 3.59 (±3.96) mm and 3.98 (±3.41) mm of lateral deviations, respectively. These results are in close agreement with those using cubic spline extrapolation techniques (3.49° ± 1.85° and 3.31 ± 4.22 mm) and adaptive neuro-fuzzy inference system (3.92° ±3.53° and 3.37 ±3.95 mm) for the same testing data. ANN can be a promising technique for prediction of scoliosis progression with substantial improvements in accuracy over current techniques, leading to potentially important implications for scoliosis monitoring and treatment decisions. Funding: AHFMR, CIHR, Fraternal Order of Eagles, NSERC, GEOIDE.
Spine and torso models were generated concurrently with x-rays for twenty-three patients undergoing scoliosis brace treatment. Clinical indices of spinal deformity and torso surface asymmetry indices were computed from models obtained when patient was first recruited and at approximately one year’s follow-up. Significant correction changes of the torso shape were detected in indices including orientation of cross-sectional principal axes of inertia (p=0.048) and Back Surface Rotation (p=0.08) though spinal corrections were from not significant to subtle (0.20_p_0.88). Trunk asymmetry should be assessed for an objective evaluation and understanding of the effect produced by a specific treatment. To assess changes in torso geometry and spinal deformity during treatment of idiopathic scoliosis with rigid brace. Relationship between torso surface geometry and spinal deformity when a rigid brace is applied is essential for better understanding of brace treatment mechanism and optimal application of external forces. Three-dimensional torso surface models were generated concurrently with postero-anterior x-rays for twenty-three patients undergoing scoliosis brace treatment, when first recruited and at approximately one year’s follow-up. Torso asymmetry indices describing principal axis orientation, back surface rotation, and asymmetry of the centroid line, left and right half-areas and the spinous process line were computed. The statistical paired t-Test (95% CI) was performed to test the probability that no difference exist after one year of treatment in both spinal and torso asymmetry indices. After one year follow-up patients showed a mean increase of only 2° for the major Cobb angle. This was consistent with not significant to subtle corrections found in clinical (p=0.88) and computed (p=0.75) Cobb angle, lateral deviation (p=0.20), orientation of plane of maximum deformity (p= 0.58) and maximum vertebral axial rotation (p=0.83). Furthermore, significant correction changes of the torso shape were detected in the orientation of cross-sectional principal axes (PAX) of inertia (p=0.048) and Back Surface Rotation (p=0.08). Here we have shown that we can acquire 3D torso surface and reliably measured a set of indices of transverse torso asymmetry. Future work will look at indication of predictive potential of torso surface indices. Funding: AHFMR, CIHR, Fraternal Order of Eagles, NSERC, GEOIDE.
Studies have shown significantly shorter hospital stays and earlier return to mobilization when epidural analgesia was used in lower extremity surgeries. This study quantified the effects of epidural analgesia on lower extremity kinetics and kinematics during gait. There were no significant differences found in hip, knee, or ankle joint moments or angles between baseline (no drug) and epidural trials, using two different drugs. These findings indicate that epidural analgesia does not alter normal gait in healthy subjects, suggesting that patients requiring epidural analgesia following orthopaedic surgery may also be able to participate in rehabilitation without significant epidural-related changes in gait. Epidural analgesia has been used post-operatively following chest, abdominal and lower extremity surgery, with significantly shorter hospital stay and earlier return to mobilization demonstrated. This study quantified the effects of epidural analgesia on lower extremity kinetics and kinematics during gait. Ten healthy volunteers were tested on different days with two drugs. With the catheter (L3-L4 intervertebral space) in place but prior to drug administration, gait was assessed. Testing was repeated 30 min after drug administration. Motion and ground reaction force data were recorded during walking with a four-camera video-based system (Motion Analysis Corp) and force platform (Kistler). No significant differences existed in 3-D hip, knee, or ankle joint moments or angles among baseline (no drug) and drug trials. These findings indicate that epidural analgesia does not alter normal gait in healthy subjects, suggesting that patients requiring epidural analgesia following orthopaedic surgery may also be able to participate in rehabilitation without significant epidural-related changes in gait. It is well documented that early mobilization and rehabilitation following orthopaedic surgery improve healing and shorten hospital stay. However, pain often limits full participation. Epidural analgesia appears to be an appropriate mode of pain relief that, despite somatosensory changes, may allow normal gait. Epidural analgesia in healthy volunteers does not alter lower extremity kinetics or kinematics, suggesting that it may be an effective mode of pain relief that will allow better participation in therapy following orthopaedic surgery.
The relations among tissue quality, socket discomfort, gait characteristics, and socket pressures are not well established for the unilateral below-knee amputee population. These relations were evaluated for six amputees at seventeen regions of interest on the residual limb. Pressure sensors were placed directly on the residual limb. Peak dynamic socket pressures were not directly related to peak joint moments. However, increases in ground reaction forces (GRFs) related to increases in socket pressures. The relations among tissue quality, socket discomfort, gait characteristics, and socket pressures are not well established for the unilateral below-knee amputee population. The purpose of this study was to evaluate these relations for six amputees. A thorough understanding of pressure distribution between the residual limb and prosthetic socket is critical to socket design and limb health. The subjects ranged in age from thirty to seventy-two years of age. The inclusion criteria were male, unilateral transtibial amputation, ability to ambulate independently, non-diabetic, no debilitating health conditions, non-recent amputee. Tissue sensation and socket discomfort were evaluated at seventeen regions of interest on the residual limb. Tissue sensation was assessed using Semmes-Weinstein monofilaments to test light touch/deep pressure sensation, tuning fork to test vibration sensation, and pinprick to test pain sensation. Socket discomfort was assessed using 10 cm Visual Analogue Scale. Gait characteristics were recorded during walking using a Motion Analysis System. Socket pressure measurements were made using F-socket pressure sensors in conjunction with I-Scan software program. Pressure sensors were placed directly on residual limb. Gait characteristics and socket pressures were compared across three different testing days. The site-specific tissue sensitivity scores did not correlate with the socket discomfort scores. In addition, site-specific discomfort scores did not correlate with peak socket pressures recorded at subject’s normal walking speed. Significant day-to-day pressure differences were found at four of the seventeen areas of interest. Peak dynamic socket pressures were not directly related to peak joint moments. Two subjects demonstrated direct relations between ground reaction forces (GRFs) and socket pressure on the different test days.
Roentgen stereophotogrammetric analysis (RSA) is a tool that can provide quantitative information for objective evaluation and comparison of implant migration. The purpose of this study was to develop and validate a new method to determine the position and orientation of an implant with RSA that does not require the implant modification or acquisition of accurate 3D implant models. This method utilizes information from certain common features of implant geometry. This method has demonstrated in-vitro precision and accuracy of 0.005 !0.059 mm in position and 0.09 ! 0.166° in orientation which is equivalent to both marker and model based RSA methods Roentgen stereophotogrammetric analysis (RSA) is a tool that can provide quantitative information for objective evaluation and comparison of implant migration. RSA measures have demonstrated the ability to both predict premature implant failure before clinical or standard radiological signs appear, and to elucidate implant wear which is considered a major causal factor in failure. To provide this functionality, RSA requires either the modification of each implant by the addition of spherical markers or the acquisition of accurate 3D models of each implant. These approaches can significantly limit the application of the RSA method. The purpose of this study was to develop and validate a new method to determine the position and orientation of an implant with RSA that does not require the modifying or acquiring accurate 3D models of each implant. This method is based on the geometric inter-relationship between the pair of RSA images and geometric information from the projected outlines of certain paired (visible in both views) features of implant geometry. Evaluations were performed on a metallic acetabular cup modified with spherical markers. The implant features used in this case where the hemispherical shell and the planar circle at the base of the acetabular cup. This method has demonstrated an average in-vitro precision and accuracy of 0.005 !0.059 mm in position and 0.09 ! 0.166° in orientation which was equivalent to that achieved with the marker based method and equivalent to published model based RSA results.