Gr Colborne

ANALYSIS OF MECHANICAL AND METABOLIC FACTORS IN THE GAIT OF CONGENITAL BELOW KNEE AMPUTEES: A Comparison of the SACH and Seattle Feet

Prosthetic feet have been developed with the intention that they deform during the first half of the stance phase, to store energy that can be released at the end of stance and contribute to push-off. The purpose of this study was to examine the three-dimensional kinematics and kinetics of gait and metabolic energy cost in children and adolescents with below-knee amputations using the SACH and Seattle prosthetic feet. The metabolic test consisted of an 8-min walk around an oval track while expired gases were collected and analyzed. The biomechanical test consisted of 10 walking trials: 5 for each of the prosthetic and sound limbs. Stance and swing phase moments and powers were calculated for both the prosthetic and sound limbs. A four-camera VICON system recorded movements of the limb segments to calculate joint kinematics, and these were combined with ground reaction force data in a three-dimensional model to determine moments and powers about the hip, knee and ankle joints. The Seattle foot produced a small increase in stride length, which led to a small increase in walking velocity. Biomechanical data revealed that the Seattle foot was less resistant to passive dorsiflexion in midstance, and although there was no effect on the work done across the prosthetic ankle, a knee flexor moment dominated the stance phase when the SACH foot was tested, whereas the Seattle foot allowed a normal extensor moment. The profile of work was unaffected by the type of foot. On the sound side, the hip produced most of the positive work while the ankle output was below normal. The metabolic results showed that the energy cost of walking was slightly lower for the Seattle foot.

Feedback of ankle joint angle and soleus electromyography in the rehabilitation of hemiplegic gait

A computer-assisted feedback system was developed to present to walking subjects instantaneous feedback of their muscle activity or joint angular excursions during gait. Targets for muscle activity or joint motion were displayed on the feedback screen along with timing cues that prompted muscle activity or joint flexion/extension at specific times during the gait cycle. The purpose was to compare the effectiveness of joint angle and electromyographic (EMG) feedback to a focused program of physical therapy for gait. Eight hemiplegic stroke patients were treated with ankle joint angle feedback, EMG biofeedback from the soleus muscle, and conventional physical therapy for gait in a three-period crossover design. PT was given either first or last in the sequence of treatments. Gait analysis prior to and following each type of treatment revealed that the feedback treatments resulted in significant increases in stride length and walking velocity and in positive changes in push-off impulse, gait symmetry, and standing weight-bearing symmetry, as evaluated in a general linear model and paired t-tests. Overall, physical therapy produced no significant changes. However, when physical therapy was the first treatment of the sequence, significant increases in stride length and velocity were observed. When physical therapy was last, there were significant negative changes in gait symmetry and standing weight-bearing symmetry, and negative trends in stride length, walking velocity, and push-off impulse. It is concluded that computer-assisted feedback is an effective tool for retraining gait in stroke patients.

Symmetry of hind limb mechanics in orthopedically normal trotting Labrador Retrievers

OBJECTIVE To evaluate symmetry of the hind limbs in orthopedically normal trotting dogs. Animals-19 orthopedically normal Labrador Retrievers with no history of lameness. PROCEDURES Retroreflective markers were applied to the hind limb joints, and a 4-camera kinematic system captured positional data at 200 Hz in tandem with force platform data collection while the dogs trotted. Morphometric data were combined with kinematic and force data in an inverse dynamics method to calculate net joint moments and powers at the joints as well as total support moment for each limb. Dogs were identified as right or left dominant when their total support moment was > 10% asymmetric between sides. RESULTS 10 of the 19 dogs were mechanically dominant in the right hind limb as determined by their total support moments. One dog was left dominant, and the remaining 8 were symmetric. Right-dominant dogs had larger net joint moments at the right hip, tarsal, and metatarsophalangeal joints and a smaller moment at the right stifle joint, compared with values for the left hind limb. The 1 left-dominant dog had the exact opposite findings. Hip and stifle joint moments and powers varied between limbs of the right-dominant and left-dominant groups in the timing of their transition from negative to positive, and power amplitudes varied at the hip, tarsal, and metatarsophalangeal joints but not the stifle joint. CONCLUSIONS AND CLINICAL RELEVANCE Sound trotting dogs can have asymmetries in limb and joint mechanics. These natural mechanical asymmetries should be taken into account when considering models to evaluate stresses at joints and when considering surgery for cruciate ligament rupture.

Joint angle, moment and power compensations in dogs with fragmented medial coronoid process

Fragmented medial coronoid process (FMCP) is the most common cause of forelimb lameness in juvenile medium and large breed dogs; however methods of assessing the disruption to their gait remain subjective. The purpose of this study was to objectively quantify the mechanical disruptions to gait in dogs with arthroscopically confirmed unilateral FMCP. Seven dogs underwent full inverse dynamic analysis at the time of diagnosis. Kinematic and force data were collected from both forelimbs at trot. Stance phase joint angles, net joint moments and net joint powers were calculated using custom software. There were gross differences in kinetic and kinematic patterns between FMCP affected and compensating forelimbs. Stance time was 0.24 sec on the lame side and 0.26 sec on the compensating side. The shoulder and the elbow were more flexed at ground contact, and elbow, carpal and MCP joints had smaller ranges of motion on the lame side. Net joint moments were significantly reduced (P < 0.05) in the elbow, carpal and MCP joints of the FMCP affected limb. Net joint powers were likewise significantly smaller (P < 0.05). However, the overall moment and power patterns persisted. Total limb support moment was significantly smaller on the affected side (P < 0.05). Total limb power was significantly reduced on the affected side (P < 0.05) being most affected in its propulsive phase in the second half of stance. Inverse dynamic analysis of this clinical condition is an objective means by which to assess the mechanical disruption to gait.

Lame broiler chickens respond to non-steroidal anti-inflammatory drugs with objective changes in gait function: A controlled clinical trial

Leg health of intensively reared broiler chickens is a significant problem, yet little is known regarding the nature of lameness-associated pain. Kinematic changes in gait have been reported in naturally lame broilers following subcutaneous non-steroidal anti-inflammatory drug (NSAID) administration, compared to a placebo group. In the current study, an extensive range of gait parameters were defined using a commercial motion-capturing system to record three-dimensional temporospatial information from walking broilers pre- and post-treatment. Data analysis, performed using multi-level models, revealed gait modifications in broilers receiving NSAID, but not in those receiving saline. The effect of walking velocity was accounted for retrospectively. An increase in velocity following NSAID treatment (carprofen: P<0.001; meloxicam: P=0.044) indicated improved walking ability. For several measures, the polarity of the treatment effect depended upon walking speed. At slow speeds certain parameters become more like those of non-lame broilers, which may have been indicative of improved stability: stride length and duration (both NSAIDs), transverse back displacement (meloxicam), and vertical leg displacement (carprofen). However, these same parameters also revealed that NSAID treatment caused imbalance at faster speeds, which may have signified an excessive dosage. Although doses employed were not conclusively effective, evidence was provided that factors besides body conformation influenced mobility in the test cohort. The study showed that the model would be useful in future studies to increase our understanding of pain associated with specific lameness types in broiler chickens.

Horizontal moment around the hoof centre of pressure during walking on right and left circles

REASONS FOR PERFORMING STUDY Recent research indicates that the digital joints experience some degree of extrasagittal motion during stance and that the moments under the hoof are asymmetric in horses walking in a straight line. On a circle, these have not been defined. OBJECTIVES To quantify the amplitude and symmetry of horizontal twisting moments around the vertical axis through the hoofs centre of pressure on left and right circles at walk. METHODS Six Thoroughbred horses were led at walk across a Kistler force platform on a left and a right circle of 5 m radius. The resultant moment around the hoof was calculated from the 4 horizontal forces and their moment arms. RESULTS Five of the 6 horses exerted an internal moment around their left forehoof, and 4 exerted an internal moment around their right forehoof on the left circle. On the right circle, 5 of the 6 exerted an internal moment around the left forehoof and a weak external moment around the right forehoof. The moments under the hind hooves were bilaterally similar for right and left circles. CONCLUSION Intrahorse variability in the applied moments is low, but there is some interhorse variability, especially in the forelimb moments, that indicates future studies of movements of the distal limb joints should be bilateral to account for mechanical asymmetry. POTENTIAL RELEVANCE The finding that horizontal moments vary between forelimbs in some horses will apply to how exercise on a circle is approached, especially in rehabilitation programmes for horses with orthopaedic injury of the distal limb.

Thoracic geometry changes during equine locomotion

Classic descriptions of rib motion during ventilation include three-dimensional movements that are tied to the locomotor pattern. It is still not clear how chest wall and diaphragmatic movements contribute to ventilation. The purpose of this paper was to evaluate how gait affects local thoracic geometry in horses. Hemispherical markers were placed on the skin over the ribs and spine to calculate thoracic hemi-diameter. Ventilatory airflows were recorded using an ultrasonic flowmeter system. Airflow and kinematic data were collected synchronously at walk (1.8 m s -1 ), trot (4 m s -1 ), canter and gallop (6, 8 and 10 m s -1 ) on the treadmill. At walk and trot, the changes in right and left hemi-diameter were approximately symmetric. At walk, mean hemi-diameter changes were 40 mm (rib 10) and 47 mm (rib 16). At trot, they were 33 mm (rib 10) and 34 mm (rib 16). Across the three canter and gallop speeds, leading (right) side hemi-diameter change increased from 25 to 30 to 35 mm (rib 10) and from 23 to 37 to 46 mm (rib 16). The trailing (left) side hemi-diameter increased from 50 to 67 to 70 mm (rib 10) and from 36 to 48 to 54 mm (rib 16) ( P ≪0.01). At canter and gallop, the non-lead side of the thorax is subjected to larger amplitude changes in hemi-diameter than the lead side, which tends to be more compressed overall and demonstrates smaller amplitudes of change in diameter.

Rehabilitation of an electrical burn patient through thermal biofeedback

A 22-year-old male subject, with high-voltage electrical burns to one wrist, utilized differential relaxation and visual biofeedback to increase skin temperature in the damaged hand. Through 14 thermal biofeedback and passive relaxation sessions, the subject was able to produce temperature increases in his damaged hand of up to 21°F, which considerably diminished the pain. Healing, feeling, and movement control seemed to progress with extreme rapidity, suggesting that axoplasmic transport was greatly enhanced.

Horizontal moment around the hoof's centre of pressure during walking in a straight line

REASONS FOR PERFORMING STUDY Joint congruity and ligaments restrain the distal limb joints from excessive motion in the transverse and frontal planes, but the magnitudes and direction of the horizontal twisting moments around the hoofs centre of pressure (CoP) that induce these motions are unknown. OBJECTIVES To quantify the horizontal moment around the vertical axis through the hoofs CoP at walk, and to determine whether these are symmetric. METHODS Nine sound Thoroughbred horses (mean age 53 years; mean mass 502 kg) were led at walk in a straight line across a Kistler force platform. Five trials were collected for each fore and hindlimb. The resultant moment around the hoofs CoP was calculated from the horizontal moment arms between the calculated CoP and the 4 horizontal forces in the transverse (X) and cranio-caudal (Y) directions. RESULTS The calculated moments were consistent within limbs and horses, but variable between horses. Hindlimbs demonstrated a biphasic moment pattern and the largest moments were typically in the first half of stance. Mean +/- s.d. peak moments were internal under both hindlimbs (L: Int 14.1 +/- 4.6 Nm; R: Int 133 +/- 5.5 Nm). In the forelimbs, 7/9 horses demonstrated an asymmetric moment pattern, with the left forelimb exerting an internal moment (L: Int 6.9 +/- 2.9 Nm) and the right forelimb an external moment (R: Ext 8.4 +/- 4.4 Nm), while the remaining 2 horses exerted internal moments in both forelimbs (L: Int 11.7 +/- 1.4 Nm; R:Int 6.6 +/- 1.9 Nm). CONCLUSION In 7/9 horses, the forelimbs exerted asymmetric horizontal moments around the hoof CoP. The hindlimbs appear to behave with mechanical symmetry during stance, exerting an internal moment during retraction. POTENTIAL RELEVANCE Extrasagittal joint motions in the forelimb are unlikely to be symmetric and future studies should account for possible bilateral variations.

An ex vivo investigation of the effect of the TATE canine elbow arthroplasty system on kinematics of the elbow

OBJECTIVE To devise a kinematic technique to objectively ascertain the location and orientation of the centre of rotation of the canine elbow and to compare this axis following arthroplasty with the first generation TATE™ prosthesis in an ex vivo model. METHODS Five pairs of cadaveric forelimbs were obtained and proximal limb soft tissues removed. Pin-mounted reflective markers were applied to the humerus and ulna. Limbs were mounted on a frame and six trials of the elbow manually cycled through its sagittal range of motion captured using 4 Qualisys cameras at 120 Hz. Radiography was performed to identify marker position. TATE™ cartridges were implanted and kinematic analysis repeated. Kinematic data were imported into custom software and the three-dimensional joint centre of rotation defined using a closed-form solution for absolute orientation. Paired t tests were performed to determine if the centre of rotation of the elbow differed significantly (P<0·05) pre- and postoperatively and between left and right limbs. RESULTS There was no significant difference in three-dimensional orientation of the elbow axis between pre and postoperative measurements or between left and right limbs. CLINICAL SIGNIFICANCE A critical factor in obtaining a successful functional outcome following elbow arthroplasty in humans is accurate reconstruction of the anatomic centre of rotation. The first generation TATE canine elbow arthroplasty cartridge and its instrumentation accurately reconstructed the anatomic centre of rotation in 8 of the 10 elbows assessed in this ex vivo model.