Objective: To evaluate the load redistribution mechanisms in walking and trotting dogs with induced forelimb lameness. Animals: 7 healthy adult Beagles. Procedures: Dogs walked and trotted on an instrumented treadmill to determine control values for peak and mean vertical force as well as vertical impulse for all 4 limbs. A small sphere was attached to the ventral pad of the right forelimb paw to induce a reversible lameness, and recordings were repeated for both gaits. Additionally, footfall patterns were assessed to test for changes in temporal gait variables. Results: During walking and trotting, peak and mean vertical force as well as vertical impulse were decreased in the ipsilateral forelimb, increased in the contralateral hind limb, and remained unchanged in the ipsilateral hind limb after lameness was induced. All 3 variables were increased in the contralateral forelimb during trotting, whereas only mean vertical force and vertical impulse were increased during walking. Stance phase duration increased in the contralateral forelimb and hind limb during walking but not during trotting. Conclusions and clinical relevance: Analysis of the results suggested that compensatory load redistribution mechanisms in dogs depend on the gait. All 4 limbs should be evaluated in basic research and clinical studies to determine the effects of lameness on the entire body. Further studies are necessary to elucidate specific mechanisms for unloading of the affected limb and to determine the long-term effects of load changes in animals with chronic lameness arabic 10 English 72
Jalal Mohamed Abdelhadi(1-2013)

Animals alter their locomotor mechanics to adapt to a loss of limb function. To better understand their compensatory mechanisms, this study evaluated the changes in the fore-aft ground forces to forelimb lameness and tested the hypothesis that dogs unload the affected limb by producing a nose-up pitching moment via the exertion of a net-propulsive force when the lame limb is on the ground. Seven healthy Beagles walked and trotted at steady speed on an instrumented treadmill while horizontal force data were collected before and after a moderate lameness was induced. Peak, mean and summed braking and propulsive forces as well as the duration each force was exerted and the time to reach maximum force were evaluated for both the sound and the lame condition. Compared with the sound condition, a net-propulsive force was produced by the lame diagonal limbs due to a reduced braking force in the affected forelimb and an increased propulsive force in the contralateral hindlimb when the dogs walked and trotted. To regain pitch stability and ensure steady speed for a given locomotor cycle, the dogs produced a net-braking force when the sound diagonal limbs were on the ground by exerting greater braking forces in both limbs during walking and additionally reducing the propulsive force in the hindlimb during trotting. Consistent with the proposed mechanism, dogs maximize their double support phases when walking. Likely associated with the fore-aft force adaptations to lameness are changes in muscle recruitment that potentially result in short- and long-term effects on the limb and trunk muscles. arabic 13 English 78
Jalal Mohamed Abdelhadi(12-2012)

Objective To (1) evaluate thoracic limb loads and symmetry, and elbow function and morphology, before and after arthroscopic treatment of unilateral medial coronoid process disease (MCPD), and (2) determine if functional variables correlate with morphologic findings.Study DesignProspective case series.AnimalsDogs (n = 14) with thoracic limb lameness.Methods Dogs were included when unilateral MCPD was confirmed as the cause of lameness. Kinetic analysis of both thoracic limbs, along with kinematic analysis and goniometry of both elbows were carried out before, and 60, 120, and 180 days after partial coronoidectomy by arthroscopy. Radiography and computed tomography of both elbows were performed before and 180 days after arthroscopy.ResultsA nonsignificant (P = .11) increase in the peak vertical loads (PFz), and a significant (P = .022) increase in the vertical impulse (iFz) applied by the affected limb were seen. Symmetry indices improved, with significant differences between sessions (PFz: P = .019; iFz: P = .003). Kinematic variables showed no significant differences, between sessions or when comparing both elbows within sessions. Goniometry revealed no significant differences between sessions, but some significant differences were identified when comparing both elbows within sessions. Osteophytosis and degree of lameness showed no correlation, before (rs = −0.077; P = .79) or after arthroscopy (rs = 0.27; P = .35).Conclusions Kinetic variables improved after arthroscopy, without full restoration of function. Kinematic variables did not change significantly. Osteoarthritis and goniometric measurements in the affected joint worsened. Functional variables did not correlate with morphologic findings. arabic 23 English 137
Jalal Mohamed Abdelhadi(7-2004)