What are the biomechanical consequences of a structural leg length discrepancy on the adolescent spine during walking?

Structural leg length discrepancy (LLD) is a common phenomenon. However, its effect on spinal gait kinematics remains unclear. How does LLD affect spinal gait kinematics in patients with structural LLD and what is the immediate effect of a shoe lift?. 10 adolescents with structural LLD (20-60 mm) and 14 healthy controls were included. All of whom were fitted with a trunk marker set and requested to walk barefoot as well as with an orthotic shoe lift (only patients). Data were collected using a 12-camera motion capture system. Group comparisons were conducted using one-dimensional Statistical Parametric Mapping (SPM). Patients with LLD showed statistically significant increased frontal plane lumbar bending angles to the longer side (p = 0.007), increased pelvic drop on the shorter side (p < 0.001) and increased hip adduction angles on the longer leg (p < 0.001) compared to the healthy controls. In the sagittal plane, patients demonstrated changed knee (shorter leg) and ankle joint (longer leg) motion. All gait deviations observed in patients with LLD could immediately be altered by correcting the LLD using a shoe lift. Due to the LLD, patients showed a lateral pelvic drop on the shorter side, which appeared to be compensated for by a contralateral bending in the lumbar spine and a lateral shift of the pelvis towards the longer side. In addition, the use of an orthotic correction seems to be a suitable option to instantly normalize gait kinematics in patients with mild to moderate LLD.

Bangerter C ，Romkes J ，Lorenzetti S ，Krieg AH ，Hasler CC ，Brunner R ，Schmid S ... -  《-》

Orthotic correction of lower limb function during gait does not immediately influence spinal kinematics in spastic hemiplegic cerebral palsy.

Foot equinus and leg length discrepancy (LLD) are common problems in hemiplegic cerebral palsy (hCP), both causing secondary deviations of pelvic motion during gait. It can therefore be assumed that the spinal deviations observed in hCP patients are secondary as a compensation for the position of the pelvis arising from the disturbed leg function. This study investigated the effects of correcting lower extremity function by orthotics on spinal gait kinematics in hCP patients. Ten adolescent hCP patients and 15 healthy controls were included. Using a validated and previously used enhanced marker set, sagittal and frontal plane spinal curvature angles as well as general trunk and lower extremity kinematics were measured while walking barefoot as well as with an orthotic correction (only hCP patients) using a 12-camera motion capture system. The hCP patients in both the barefoot and orthotic conditions indicated clinically relevant greater lumbar lordosis angles (d≥0.96, p≤0.071), smaller thoracic kyphosis angles (d≥0.84, p≤0.142) and differences in frontal plane lumbar curvature angles (d≥1.00, p≤0.105) compared to controls. However, these angles were not influenced by the successful restoration of a normal heel-to-toe gait pattern and the correction of any LLD using lower extremity orthotics. Spinal gait deviations in adolescents with mild hCP seemed not to result secondarily from foot equinus or LLD, but probably from structural deformities such as hip flexor contractures. Future research should address long-term effects of an AFO treatment as well as the relationship between spinal kinematics and severity of disease.

Schmid S ，Romkes J ，Taylor WR ，Lorenzetti S ，Brunner R ... -  《-》

Gait patterns in children with limb length discrepancy.

Aiona M ，Do KP ，Emara K ，Dorociak R ，Pierce R ... -  《-》

Mild leg length discrepancy affects lower limbs, pelvis and trunk biomechanics of individuals with knee osteoarthritis during gait.

Leg length discrepancy greater than 1cm increases odds of progressive knee osteoarthritis in the shorter limb. Biomechanical data of 15 knee osteoarthritis participants were collected while they walked under two conditions: (1) control - wearing thick sandals; (2) short limb - wearing a thin sandal on the osteoarthritic limb and a thick sandal on the contralateral limb. The thick and thin sandals had 1.45cm of thickness difference. The knee osteoarthritis limb was analyzed for both conditions. Ankle, knee, hip, pelvis and trunk kinematics and moments were measured with a motion and force capture system. Principal component analysis and mean hypothesis' tests were used to compare the conditions. The short limb condition reduced rearfoot plantarflexion in loading response and increased plantarflexion in late stance (p<0.001), increased ankle dorsiflexion moment (p=0.003), increased knee flexion angle in loading response and delayed knee flexion in late stance (p=0.001), increased knee extension moment in loading response and increased knee flexion moment in terminal stance (p=0.023), reduced hip extension moment in early stance and reduced hip flexion moment in late stance (p<0.001), reduced knee adduction moment (p=0.015), reduced hip adduction angle (p=0.001) and moment (p=0.012) and increased pelvic (p=0.023) and trunk (p=0.001) external rotation. Mild leg length discrepancy affects the entire kinetic chain of individuals with knee osteoarthritis during gait, increasing knee sagittal plane loading, which helps to explain why mild leg length discrepancy accelerates knee osteoarthritis progression. Mild leg length discrepancy should not be overlooked in knee osteoarthritis individuals.

Resende RA ，Kirkwood RN ，Deluzio KJ ，Morton AM ，Fonseca ST ... -  《-》

Effects of orthotic insole on gait patterns in children with mild leg length discrepancy.

Leg length discrepancy (LLD) is commonly associated with compensatory gait strategies leading to musculoskeletal disorders of the lower extremity and lumbar spine. Orthotic insole (OI) is considered as a conservative treatment for patients with mild LLD, especially for children. However, the restoration of normal gait when wearing OI with foot lift are still poorly understood. What are the immediate effects of OI on the gait patterns in children with mild LLD? Gait data and plantar pressure data were collected for 12 children with mild anatomical LLD in barefoot and OI conditions. Paired t-test was performed to determine the changes in gait between these two conditions, and also the symmetry between limbs in the same condition for spatiotemporal, kinematic, and kinetic variables. Children with mild LLD showed an immediate gait improvement confirmed by increased step length and velocity, decreased peak plantar pressure in both limbs with OI. Additionally, the significant between-limb differences disappeared for peak ankle dorsiflexion, hip adduction, pelvis upward obliquity and also second peak plantar pressure with OI, which improved gait symmetry. This study provides a better understanding of the immediate effect of OI with foot lift on biomechanical changes in gait, which identify that OI with foot lift could be a potential therapeutic option for children with mild structural LLD to improve gait metrics.

Shi Y ，Pang H ，Xu H ，Li X ，Cao Y ，Merryweather A ，Zheng P ，Xiang J ... -  《-》