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.

BACKGROUND: This study employs multi-segment foot modeling (MSFM) to examine flatfoot reconstruction among ambulatory children with cerebral palsy (CP). RESEARCH QUESTION: Does flatfoot reconstruction improve MSFM measures, physical examination and radiographic variables for forefoot varus and midfoot collapse and associated multi-planar compensatory features? METHODS: 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. RESULTS: 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. SIGNIFICANCE: 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.

Assessment of three-dimensional lumbar spine vertebral motion during gait with use of indwelling bone pins.

BACKGROUND: This study quantifies the three-dimensional motion of lumbar vertebrae during gait via direct in vivo measurement with the use of indwelling bone pins with retroreflective markers and motion capture. Two previous studies in which bone pins were used were limited to instrumentation of two vertebrae, and neither evaluated motions during gait. While several imaging-based studies of spinal motion have been reported, the restrictions in measurement volume that are inherent to imaging modalities are not conducive to gait applications. METHODS: Eight healthy volunteers with a mean age of 25.1 years were screened to rule out pathology. Then, after local anesthesia was administered, two 1.6-mm Kirschner wires were inserted into the L1, L2, L3, L4, L5, and S1 spinous processes. The wires were clamped together, and reflective marker triads were attached to the end of each wire couple. Subjects underwent spinal computed tomography to anatomically register each vertebra to the attached triad. Subjects then walked several times in a calibrated measurement field at a self-selected speed while motion data were collected. RESULTS: Less than 4° of lumbar intersegmental motion was found in all planes. Motions were highly consistent between subjects, resulting in small group standard deviations. The largest motions were in the coronal plane, and the middle lumbar segments exhibited greater motions than the segments cephalad and caudad to them. Intersegmental lumbar flexion and axial rotation motions were both extremely small at all levels. CONCLUSIONS: The lumbar spine chiefly acts to contribute abduction during stance and adduction during swing to balance the relative motions between the trunk and pelvis. The lumbar spine acts in concert with the thoracic spine. While the lumbar spine chiefly contributes coronal plane motion, the thoracic spine contributes the majority of the transverse plane motion. Both contribute flexion motion in an offset phase pattern. CLINICAL RELEVANCE: This is a valid model for measuring the three-dimensional motion of the spine. Normative data were obtained to better understand the effects of spine disorders on vertebral motion over the gait cycle.

Measurement and management of errors in quantitative gait data.

Gait analysis is a valuable tool in the evaluation of children and adults with movement disorders. The data produced from gait analysis, however, is not necessarily free of errors. The purpose of this study was two-fold: (i) to estimate the errors associated with quantitative gait data; and (ii) to propose a method for incorporating the knowledge of these errors into the clinical interpretation process. An experimental protocol was designed that allowed within-subject, within-observer and between-observer errors to be computed at each point in the gait cycle. The estimates were then used in a practical scheme for detecting significant deviations in joint angles. The results of this study provide a means for managing error, while simultaneously improving the rigor and objectivity of clinical interpretations.