Analysis of Postoperative Gait, Hip Strength, and Patient-Reported Outcomes After OTA/AO 61-B and 61-C Pelvic Ring Injuries.

OBJECTIVES: To examine clinical gait parameters, hip muscle strength, pelvic functional outcomes, and psychological outcomes after surgical fixation of OTA/AO 61-B and 61-C pelvic ring injuries. DESIGN: Retrospective review identified 10 OTA/AO 61-B patients and 9 OTA/AO 61-C patients for recruitment who were between 1 and 5 years after pelvic fixation. Gait and strength assessments, and patient-reported outcome scores were performed/collected and analyzed. SETTING: Outpatient clinical motion performance laboratory. PATIENTS/PARTICIPANTS: Patients with OTA/AO 61-B and OTA/AO 61-C fractures who were between 1 and 5 years after pelvic fixation. MAIN OUTCOME MEASUREMENTS: Hip strength, kinetics, and spatial-temporal outcomes; Majeed Pelvic Outcome Score; Short Form 36; Hamilton Anxiety/Depression Rating Scales. RESULTS: There were no differences in age, body mass index, or time since definitive fixation between OTA/AO 61-B and 61-C groups. The OTA/AO 61-C group had higher median injury severity scores, longer length of stay, and greater postoperative pelvic fracture displacement. There was no difference in bilateral hip strength, bilateral peak hip moments, peak hip power, and walking speed between groups. Patients with OTA/AO 61-C fractures had lower scores on Short Form 36 General Health and Majeed Work, with a trend toward a lower Total Majeed score. There were no differences in self-reported total anxiety and depression symptoms. CONCLUSIONS: This study did not identify any gait, strength, or psychological differences between OTA/AO 61-B and 61-C injuries at 1-5 years of follow-up. However, increased injury severity in OTA/AO 61-C patients may have residual consequences on perceived general health and ability to work. This pilot study establishes a template for future research into functional recovery of patients with severe pelvic ring trauma. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Relative phase measures of intersegmental coordination describe motor control impairments in children with cerebral palsy who exhibit stiff-knee gait.

BACKGROUND: The purpose of this retrospective study was to explore lower limb intersegmental coordination as a clinically important indicator of motor control mechanisms in individuals with cerebral palsy exhibiting stiff-knee gait. We used the relative phase of thigh and foot segments around foot-off to describe motor control, given the relevance of the pre-swing phase of gait to the existence of stiff-knee gait. METHODS: Traditional gait parameters and thigh/foot intersegmental coordination were calculated using pre-and postoperative kinematic data from a cohort of 54 subjects (92 legs) with spastic cerebral palsy. All participants had stiff-knee gait, walked without assistive devices, and underwent rectus femoris transfer surgery to improve swing period knee flexion. Analyses included correlations between a) preoperative intersegmental coordination and gait variables (knee flexion range, rate and gait performance) and b) pre-to-postoperative intersegmental coordination change and change in gait variables. FINDINGS: Thigh/foot intersegmental coordination significantly (P < 0.001) correlated with knee flexion range, rate and walking speed. Postoperative intersegmental coordination was significantly more uncoupled than preoperative. Pre-to-postoperative intersegmental coordination improvement also significantly correlated with improvements in knee flexion range, rate and walking speed. Pre-to-postoperative changes in intersegmental coordination accounted for 43% and 36% of variance in knee flexion range change and knee flexion rate change respectively. INTERPRETATION: Intersegmental coordination is a clinically important factor in knee flexion limitations associated with stiff-knee gait for individuals with cerebral palsy. These findings are a foundation for further study of intersegmental coordination measures as complements to traditional instrumented gait analysis.

Energy neutral: the human foot and ankle subsections combine to produce near zero net mechanical work during walking.

The human foot and ankle system is equipped with structures that can produce mechanical work through elastic (e.g., Achilles tendon, plantar fascia) or viscoelastic (e.g., heel pad) mechanisms, or by active muscle contractions. Yet, quantifying the work distribution among various subsections of the foot and ankle can be difficult, in large part due to a lack of objective methods for partitioning the forces acting underneath the stance foot. In this study, we deconstructed the mechanical work production during barefoot walking in a segment-by-segment manner (hallux, forefoot, hindfoot, and shank). This was accomplished by isolating the forces acting within each foot segment through controlling the placement of the participants' foot as it contacted a ground-mounted force platform. Combined with an analysis that incorporated non-rigid mechanics, we quantified the total work production distal to each of the four isolated segments. We found that various subsections within the foot and ankle showed disparate work distribution, particularly within structures distal to the hindfoot. When accounting for all sources of positive and negative work distal to the shank (i.e., ankle joint and all foot structures), these structures resembled an energy-neutral system that produced net mechanical work close to zero (-0.012 ± 0.054 J/kg).

POSTURAL STABILITY AND KINETIC CHANGE IN SUBJECTS WITH PATELLOFEMORAL PAIN AFTER A NINE-WEEK HIP AND CORE STRENGTHENING INTERVENTION.

BACKGROUND: Idiopathic patellofemoral pain (PFP) has been linked to hip weakness and abnormal lower extremity mechanics. The effect of a strengthening intervention on balance has not been well studied among individuals with PFP. HYPOTHESIS/PURPOSE: The primary aim of this study was to evaluate changes in center of pressure displacement during the single limb squat following a nine-week physical therapy intervention among adolescent females with PFP. STUDY DESIGN: Interventional and cross-sectional. METHODS: Seven adolescent females with PFP (10 extremities) were included in the study. Center of Pressure (CoP) excursions during a single limb squat task were measured before and after a nine week of physical therapy intervention focused on strengthening of the hip and core. Seven asymptomatic females were matched to the PFP group on the basis of age and activity level, and were tested as a reference group. CoP trajectories were reduced into four variables: mean distance (MDIST), root-mean-square distance (RDIST), range (RANGE), and 95% confidence interval circle area (AREA-CC). Maximum knee flexion angle, peak knee power generation and absorption were also recorded. Linear mixed models were used to test for within and between group differences in CoP metrics. RESULTS: Pre-intervention, CoP range, knee power absorption and generation were significantly decreased in the PFP group relative to the reference group. Post-intervention, the PFP group reported a significant decrease in symptom severity. There was also a significant (p<0.05) increase in MDIST, RDIST, RANGE, AREA-CC, peak knee flexion angle, peak power absorption and power generation. There was no difference (p>0.05) in knee flexion, knee power or CoP displacement between the two groups after the physical therapy intervention. CONCLUSION: Hip and core-strengthening resulted in a significant decrease in symptom severity as well as significant reductions in CoP displacement. LEVEL OF EVIDENCE: 3.

Analysis of Reach-to-Grasp by School-Aged Children with Down Syndrome Elucidates Limitations in Upper Extremity Motor Control.

AIMS: To identify limitations in preparatory planning (PP) and movement execution that constrain performance of reach-to-grasp (RTG) movements in school-aged children with Down syndrome (DS) and examine the effect of chronological age (CA) on performance. METHODS: Nine children with DS ages 6 to 12 years and nine with typical development (TD) participated in this pilot descriptive study. Three-dimensional kinematic analysis was applied to RTG movements performed in the context of two functional tasks. RESULTS: PP variables focused on the coordination of reach and grasp. Compared to the group with TD, the group with DS demonstrated significant limitations in anticipatory slowing down of hand transport and orientation of the hand in preparation for object contact. There was also relatively late onset of preparatory grip formation in the group with DS. In regard to movement execution, reach trajectories of the group with DS showed significantly greater deviation from the straight path. Correlations of study variables with CA were low and insignificant in both groups. CONCLUSIONS: Motor control mechanisms that mediate both PP and execution of the fundamental RTG movement are potential factors limiting upper extremity activity in school-aged children with DS. They should be addressed in future intervention-based research.

Sagittal plane coordination dynamics of typically developing gait.

BACKGROUND: Individuals who undergo an instrumented gait analysis often have an aberrant gait pattern due to neuromuscular impairments that adversely affect their coordination. Conventional instrumented gait analysis descriptors fail to capture the complex coordination dynamics of gait. This paper presents a straightforward methodology for generating descriptors of coordination dynamics based on dynamical systems theory and provides the largest reported dataset of sagittal plane coordination measures, including adjacent and non-adjacent segment pairings, from individuals free of gait pathology walking over-ground. METHODS: Tri-planar marker trajectories from 104 unimpaired subjects between the ages of 8 and 66 years were collected as they walked at a self-selected speed on a level surface. Phase portraits for the pelvis, thigh, shank, and foot and continuous relative phase diagrams for the segment pairs of pelvis-thigh, thigh-shank, shank-foot, and thigh-foot were calculated. FINDINGS: The low coefficients of variation for each coordination curve are comparable to inter-subject coefficients of variation for kinematic curves, narrow confidence intervals for relative phase angles at four essential footfall conditions, and small standard deviation bands of the continuous relative phase diagrams are evidence that these curves characterize the coordination dynamics of normal gait. INTERPRETATION: These findings support the use of this normative dataset as a reference for coordination studies in the clinic or research laboratory. Improving our understanding of gait strategies from the level of coordination and characterizing the natural variability in gait patterns offer a means to enhance our understanding of atypical gait patterns.