Kinematic foot types in youth with pes planovalgus secondary to cerebral palsy.

Kinematic variability of the foot and ankle segments exists during ambulation among individuals with pes planovalgus (PPV) secondary to cerebral palsy (CP). Clinicians have previously recognized such variability through classification schemes to identify subgroups of individuals, but have been unable to identify kinematic foot types. The purpose of this work was to identify kinematic foot types among children with PPV secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during gait as inputs for principal component analysis (PCA) and K-means cluster analysis. In a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 31 children/adolescents with pes planovalgus (49 feet) and 16 typically developing (TD) children/adolescents (31 feet). PCA was used as a data reduction technique on 34 kinematic variables. K-means cluster analysis was performed on the identified principal components (PCs) and one-way analyses of variance (ANOVA) was done to determine the effect of subgroup membership on PC scores. The PCA reduced the kinematic variables to seven PCs which accounted for 91% of the total variance. Six distinct kinematic foot types were identified by the cluster analysis. The foot types showed unique kinematic characteristics in both the hindfoot and forefoot. This study provides further evidence of kinematic variability in the foot and ankle during ambulation associated with pes planovalgus secondary to CP. The specific contributions of the hindfoot and forefoot would not have been detected using a single segment foot model. The identification of kinematic foot types with unique foot and ankle characteristics has the potential to improve treatment since patients within a foot type are likely to benefit from similar intervention(s).

Amene J ，Krzak JJ ，Kruger KM ，Killen L ，Graf A ，Altiok H ，Smith PA ，Harris GF ... -  《-》

Kinematic foot types in youth with equinovarus secondary to hemiplegia.

Elevated kinematic variability of the foot and ankle segments exists during gait among individuals with equinovarus secondary to hemiplegic cerebral palsy (CP). Clinicians have previously addressed such variability by developing classification schemes to identify subgroups of individuals based on their kinematics. To identify kinematic subgroups among youth with equinovarus secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during locomotion as inputs for principal component analysis (PCA), and K-means cluster analysis. In a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 24 children/adolescents with equinovarus and 20 typically developing children/adolescents. PCA was used as a data reduction technique on 40 variables. K-means cluster analysis was performed on the first six principal components (PCs) which accounted for 92% of the variance of the dataset. The PCs described the location and plane of involvement in the foot and ankle. Five distinct kinematic subgroups were identified using K-means clustering. Participants with equinovarus presented with variable involvement ranging from primary hindfoot or forefoot deviations to deformtiy that included both segments in multiple planes. This study provides further evidence of the variability in foot characteristics associated with equinovarus secondary to hemiplegic CP. These findings would not have been detected using a single segment foot model. The identification of multiple kinematic subgroups with unique foot and ankle characteristics has the potential to improve treatment since similar patients within a subgroup are likely to benefit from the same intervention(s).

Krzak JJ ，Corcos DM ，Damiano DL ，Graf A ，Hedeker D ，Smith PA ，Harris GF ... -  《-》

Segmental kinematic analysis of planovalgus feet during walking in children with cerebral palsy.

Pes planovalgus (flatfoot) is a common deformity among children with cerebral palsy. The Milwaukee Foot Model (MFM), a multi-segmental kinematic foot model, which uses radiography to align the underlying bony anatomy with reflective surface markers, was used to evaluate 20 pediatric participants (30feet) with planovalgus secondary to cerebral palsy prior to surgery. Three-dimensional kinematics of the tibia, hindfoot, forefoot, and hallux segments are reported and compared to an age-matched control set of typically-developing children. Most results were consistent with known characteristics of the deformity and showed decreased plantar flexion of the forefoot relative to hindfoot, increased forefoot abduction, and decreased ranges of motion during push-off in the planovalgus group. Interestingly, while forefoot characteristics were uniformly distributed in a common direction in the transverse plane, there was marked variability of forefoot and hindfoot coronal plane and hindfoot transverse plane positioning. The key finding of these data was the radiographic indexing of the MFM was able to show flat feet in cerebral palsy do not always demonstrate more hindfoot eversion than the typically-developing hindfoot. The coronal plane kinematics of the hindfoot show cases planovalgus feet with the hindfoot in inversion, eversion, and neutral. Along with other metrics, the MFM can be a valuable tool for monitoring kinematic deformity, facilitating clinical decision making, and providing a quantitative analysis of surgical effects on the planovalgus foot.

Kruger KM ，Konop KA ，Krzak JJ ，Graf A ，Altiok H ，Smith PA ，Harris GF ... -  《-》

Surgical treatment of pes planovalgus in ambulatory children with cerebral palsy: Static and dynamic changes as characterized by multi-segment foot modeling, physical examination and radiographs.

This study employs multi-segment foot modeling (MSFM) to examine flatfoot reconstruction among ambulatory children with cerebral palsy (CP). Does flatfoot reconstruction improve MSFM measures, physical examination and radiographic variables for forefoot varus and midfoot collapse and associated multi-planar compensatory features? MSFM was performed preoperatively and postoperatively in a cohort of ambulatory CP patients undergoing flatfoot reconstruction (surgical group, n = 24). A comparison group of non-surgical group of ambulatory CP patients with pes planovalgus (flatfoot) who did not undergo flatfoot reconstruction was also identified (n = 17). All patients in this comparison group underwent MSFM at two separate time points. Physical examination was performed and standing AP and lateral foot radiographs were obtained during each gait analysis session. Patients in the surgical group had improvement in their forefoot varus deformity, as documented on physical examination and kinematics in the STJN position of the foot and ankle, as well as in the compensatory hindfoot eversion and midfoot abduction during stance phase of gait. Furthermore, patients in the surgical group had improvement in midfoot collapse as identified kinematically by midfoot dorsiflexion, physical examination descriptors of midfoot position, and radiographic measures of calcaneal pitch and AP and lateral talar-first metatarsal angle. Patients in the non-surgical comparison group did not demonstrate these changes. Improvements in foot motion after flatfoot reconstruction in ambulatory CP patients were identified by MSFM, physical examination measures, and radiographs. Patients in the surgical and non-surgical groups had similar pre-operative radiographic findings, suggesting that physical examination and MSFM data were important in the surgical decision making process. Finally, surgical intervention did not fully restore normal foot kinematic, physical examination, and radiographic parameters, which suggests that a different, perhaps more aggressive, surgical approach for flatfoot reconstruction is needed.

Nahm NJ ，Sohrweide SS ，Wervey RA ，Schwartz MH ，Novacheck TF ... -  《-》

Multi-segment foot kinematics during gait in children with spastic cerebral palsy.

Foot deformities (e.g. planovalgus and cavovarus) are very common in children with spastic cerebral palsy (CP), with the midfoot often being involved. Dynamic foot function can be assessed with 3D gait analysis including a multi-segment foot model. Incorporating a midfoot segment in such a model, allows quantification of separate Chopart and Lisfranc joint kinematics. Yet, midfoot kinematics have not previously been reported in CP. What is the difference in multi-segment kinematics including midfoot joints between common foot deformities in CP and typically-developing feet? 103 feet of 57 children with spastic CP and related conditions were retrospectively included and compared with 15 typically-developing children. All children underwent clinical gait analysis with the Amsterdam Foot Model marker set. Multi-segment foot kinematics were calculated for three strides per foot and averaged. A k-means cluster analysis was performed to identify foot deformity groups that were present within CP data. The deformity type represented by each cluster was based on the foot posture index. Kinematic output of the clusters was compared to typically-developing data for a static standing trial and for the range of motion and kinematic waveforms during walking, using regular and SPM independent t-tests respectively. A neutral, planovalgus and varus cluster were identified. Neutral feet showed mostly similar kinematics as typically-developing data. Planovalgus feet showed increased ankle valgus and Chopart dorsiflexion, eversion and abduction. Varus feet showed increased ankle varus and Chopart inversion and adduction. This study is the first to describe Chopart and Lisfranc joint kinematics in different foot deformities of children with CP. It shows that adding a midfoot segment can provide additional clinical and kinematic information. It highlights joint angles that are more distinctive between deformities, which could be helpful to optimize the use of multi-segment foot kinematics in the clinical decision making process.

Schallig W ，Piening M ，Quirijnen L ，Witbreuk MM ，Buizer AI ，van der Krogt MM ... -  《-》