Is a Three-component Video-based Version of the Foot Posture Index Valid for Assessing Pediatric Patients With Orthopaedic and Neurologic Foot Conditions?

BACKGROUND: The Foot Posture Index-6 (FPI6) is an assessment of foot position that can be useful for patients with orthopaedic complaints. The FPI6 rates six components of foot position from -2 to +2, resulting in a total score on a continuum between -12 (severe cavus or supination) to +12 (severe planus or pronation). The subscores are ratings made by the examiner and are subjective assessments of deformity severity. The FPI6 requires palpation of bony structures around the foot and therefore must be administered live during physical examination. Because it is sometimes impractical to perform these assessments live, such as for retrospective research, a valid and reliable video-based tool would be very useful. QUESTIONS/PURPOSES: This study examines a version of the FPI using three of the original six components to determine: (1) Are scores from the three-component version of the FPI (FPI3) associated with those from the original six-component version (FPI6)? (2) Is the three-component FPI3 as reliable as the original six-component FPI6? (3) Are FPI3 assessments done retrospectively from video as reliable as those done live? METHODS: A retrospective group of 155 participants (106 males; mean age 13 ± 4 years) was studied. All had undergone gait analysis including videotaping and in-person assessment using the FPI6. Ratings for three components (calcaneus inversion/eversion, medial arch congruence, and forefoot abduction/adduction) were extracted yielding an FPI3 score ranging from -6 to +6. The other three components of the FPI6 (talar head palpation, curves above and below the lateral malleolus, talonavicular joint bulge) were excluded from the FPI3. FPI6 and FPI3 scores and side-to-side asymmetry were compared for all participants and for diagnosis subgroups (cerebral palsy and Charcot-Marie-Tooth disease) using a Pearson correlation. Agreement for foot posture categorization between the FPI6 and FPI3 was assessed using weighted kappa. Intra- and interrater reliability of live and video-based assessments for the FPI3 and its components were examined using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. RESULTS: Scores from the FPI3 and FPI6 are highly associated with each other, suggesting the FPI3 is an adequate substitute for the FPI6. FPI6 and FPI3 scores (r = 0.98) and asymmetry (r = 0.96) were highly correlated overall and within the cerebral palsy (r = 0.98 for scores; r = 0.98 for asymmetry) and Charcot-Marie-Tooth (r = 0.96 for scores; r = 0.90 for asymmetry) subgroups (all p < 0.001). Agreement between the FPI6 and FPI3 was high for foot posture categorization (weighted agreement = 95%, weighted κ = 0.88; p < 0.001). Interrater reliability for live ratings was similar for FPI3 and FPI6 and high for both measures (ICC = 0.95 for FPI6 and 0.94 for FPI3; both p < 0.001). High reliability was seen in video versus live ratings for the FPI3 total score and each of its components regardless of whether they were performed by the same (ICC = 0.98) or different (ICC = 0.97) raters (both p < 0.001), and interrater reliability remained high when the FPI3 was scored from video recordings (ICC = 0.96; p < 0.001). CONCLUSION: The FPI3 is valid and reliable when done live or from video or by the same or different examiners. It is suitable for retrospective and multicenter research studies, provided videos are done using standardized protocols. Further research is recommended investigating possible ceiling and floor effects in patients with pathologic conditions.Level of Evidence Level III, diagnostic study.

Anterior Distal Femoral Hemiepiphysiodesis Does Not Change Pelvic Tilt in Children With Cerebral Palsy.

BACKGROUND: Anterior distal femoral hemiepiphysiodesis (ADFH) is a surgical treatment choice to correct flexed knee gait and fixed knee flexion deformities in children with cerebral palsy who are skeletally immature. Increased anterior pelvic tilt has been reported after surgeries that correct knee flexion deformities, including hamstring lengthening (HSL) and distal femoral extension osteotomies, but anterior pelvic tilt has not been studied after ADFH. We hypothesized that anterior pelvic tilt would increase after ADFH, especially when combined with HSL, and it would correlate with the change in minimum knee flexion in stance and dynamic hamstring lengths. METHODS: Thirty-four eligible participants (age: 13.0, SD: 2.0) were included. Change in mean pelvic tilt across the gait cycle was compared as a function of clinical and gait parameters using linear mixed models. The relationship of change in pelvic tilt to change in other variables was examined using Pearson correlation. RESULTS: Overall, anterior pelvic tilt increased significantly after ADFH by 4.4 degrees ( P = 0.02). Further, the analysis revealed anterior pelvic tilt only increased significantly in the group that had concurrent HSL (11.1 degrees, P < 0.001). Overall, minimum knee flexion significantly decreased (increase in knee extension) in stance (-19.1 degrees, P < 0.001) and there was an increase in maximum normalized dynamic hamstring lengths (0.03, P < 0.001). The anterior pelvic tilt increased significantly in Gross Motor Function Classification System levels III to IV (5.9 degrees, P = 0.02) but did not change significantly in Gross Motor Function Classification System I to II (2.5 degrees, P = 0.37). Change in pelvic tilt was correlated with change in maximum dynamic hamstring lengths ( r = 0.87, P < 0.0001) and change in minimum knee flexion in stance ( r = -0.71, P < 0.0001). CONCLUSIONS: Anterior distal hemiepiphysiodesis without concurrent HSL for flexion knee deformities does not result in increased anterior pelvic tilt. Surgeons should consider anterior distal hemiepiphysiodesis in patients with cerebral palsy and flexed knee gait, who preoperatively have long dynamically modeled hamstrings, are skeletally immature, and when maintenance of pelvic tilt is desired. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Does Size Really Matter? Incidence of Periprosthetic Fractures After Femoral Osteotomy in Patients With Cerebral Palsy.

OBJECTIVE: Of children, 30% to 35% with cerebral palsy (CP) develop hip subluxation or dislocation and often require reconstructive hip surgery, including varus derotation osteotomy (VDRO). A recent literature review identified postoperative fractures as the most common complication (9.4%) of VDROs. This study aimed to assess risk factors for periprosthetic fracture after VDRO in children with CP. METHODS: A total of 347 patients (644 hips, 526 bilateral hips) with CP and hip subluxation or dislocation (129 females; mean age at index VDRO: 8.6 y, SD 3.4, range: 1.5 to 17.7; 2 Gross Motor Function Classification System (GMFCS) I, 35 GMFCS II, 39 GMFCS III, 119 GMFCS IV, 133 GMFCS V, 21 unavailable) were included in this retrospective, single-group intervention (VDRO) study at a tertiary referral center. Imaging and clinical documentation for patients age 18 years or younger at index surgery, treated with VDRO were reviewed to determine demographic data, GMFCS level, surgeon, type of hardware implanted, use of anticonvulsants and steroids, type of postoperative immobilization, presence of periprosthetic fractures, fracture location and mechanism, and time from surgery to fracture. Potential determinants of periprosthetic fractures were assessed using mixed effects logistic regression. RESULTS: Of 644 hips, 14 (2.2%, 95% CI: 1.3%, 3.6%) sustained a periprosthetic fracture, at a median of 2.1 years postoperatively (interquartile range: 4.6 y, range: 1.2 mo to 7.8 y). Patients with a fracture had a median age at index surgery of 7.3 years (interquartile range: 4.3, range: 2.8 to 17.8; 1 GMFCS II, 6 GMFCS IV, 7 GMFCS V). Periprosthetic fractures were not significantly related to age at index surgery ( P = 0.18), sex ( P = 0.30), body mass index percentile ( P = 0.87), surgery side ( P = 0.16), anticonvulsant use ( P = 0.35), type of postoperative immobilization ( P = 0.40), GMFCS level ( P = 0.31), or blade plate size ( P = 0.17). Only surgeon volume significantly related to periprosthetic fracture (odds ratio = 5.03, 95% CI: 1.53, 16.56, P = 0.008), with the highest-volume surgeon also using smaller blade plates ( P < 0.01). CONCLUSIONS: Periprosthetic fractures after VDRO surgery in children with CP are uncommon, and routine hardware removal appears unnecessary. The data suggest that the common dogma of putting in the largest blade plate possible to maximize fixation may increase the risk of periprosthetic fracture. Due to the overall low fracture rate, especially when contextualized relative to the risk of hardware removal, a reactive approach to hardware removal appears warranted. LEVEL OF EVIDENCE: Level III-retrospective study (targeting varus derotational osteotomies in children with cerebral palsy).

Gait Analysis Characteristics in Relapsed Clubfoot.

BACKGROUND: Relapse rates of clubfoot deformity after initial correction range between 19% and 68% regardless of treatment approach. Most studies focus on relapse before age 4. Little research has focused on late clubfoot relapse. The purpose of this study was to compare the gait characteristics of children with late clubfoot relapse (age ≥5 y) following treatment with the Ponseti method only compared with intra-articular and extra-articular surgeries. METHODS: A retrospective review was conducted of all patients with idiopathic clubfoot ≥5 years old who underwent computerized gait analysis for clubfoot relapse between 2001 and 2021. Joint range of motion, muscle strength, gait kinematics, and kinetics were compared among 3 groups based on prior clubfoot treatment: (1) Ponseti casting, (2) Extra-articular (EA) surgery, and (3) Intra-articular (IA) surgery. RESULTS: Sixty-eight subjects (107 feet) were included (39 bilateral). Thirty-one percent of feet had been treated with Ponseti casting alone; 57% had IA surgery, and 12% had EA surgery. The average age when presenting with late relapse was 8.2 years, 9.0 years and 10.7 years for the Ponseti, and IA and EA groups, respectively. The IA group had greater passive dorsiflexion than the other 2 groups (P<0.002), greater inversion weakness than the other 2 groups (P<0.0001), greater dorsiflexion during the stance phase of gait compared with the Ponseti group (P=0.001), and lower maximum power production at push-off compared with the other 2 groups (P=0.009). CONCLUSION: Late relapse can occur after all types of clubfoot correction. Consistent with existing literature, patients who have undergone posteromedial release surgery have significantly greater plantarflexor weakness resulting in poorer plantarflexor moment and power production during gait. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

The Effects of Prolonged Vibrotactile EMG-Based Biofeedback on Ankle Joint Range of Motion During Gait in Children with Spastic Cerebral Palsy: A Case Series.

AIMS: The objective of this case series was to examine the feasibility of vibrotactile EMG-based biofeedback (BF) as a home-based intervention tool to enhance sensory information during everyday motor activities and to explore its effectiveness to induce changes in active ankle range of motion during gait in children with spastic cerebral palsy (CP). METHODS: Ten children ages 6 to 13 years with spastic CP were recruited. Participants wore two EMG-based vibro-tactile BF devices for at least 4 hours per day for 1-month on the ankle and knee joints muscles. The device computed the amplitude of the EMG signal of the target muscle and actuated a silent vibration motor proportional to the magnitude of the EMG. RESULTS: Our results demonstrated the feasibility of the augmented sensory information of muscle activity to induce changes of the active ankle range of motion during gait for 6 children with an increase ranging from 8.9 to 51.6% compared to a one-month period without treatment. CONCLUSIONS: Preliminary findings of this case series demonstrate the feasibility of vibrotactile EMG-based BF and suggest potential effectiveness to increase active ankle range of motion, therefore serving as a promising therapeutic tool to improve gait in children with spastic CP.

Variation in Functional Mobility Within Gross Motor Function Classification System Levels.

BACKGROUND AND OBJECTIVE: Variation in walking performance within Gross Motor Function Classification System (GMFCS) levels for patients with cerebral palsy (CP) is often unrecognized. The Functional Mobility Scale (FMS) rates mobility at household, school, and community distances. This study evaluated the variability of walking performance within GMFCS levels as measured by the FMS. METHODS: Retrospective review of gait analysis records for ambulatory patients with CP. FMS rating distribution at each distance was examined for GMFCS levels I-IV within age groups (below 12 or above 12 y) and compared among levels using χ2 tests. RESULTS: A total of 788 patients (499 male; age 11.2, SD 3.9 y) were included. FMS score distribution differed significantly among GMFCS levels for all distances (P<0.001). GMFCS LEVEL: I-Children walked independently on all surfaces at home and school distances at all ages. In all, 5% to 7% used wheeled mobility in the community. II-Most walked at home and school distances. Some younger children crawled at home, and 5% to 8% of all subjects used walls and furniture. Approximately 50% of subjects in both age groups used some form of walking aids or a stroller/wheelchair in the community. III-Twenty-five percent to 30% walked unaided at home, requiring walking aids or wheeled mobility at school or in the community. Forty-five percent of younger and 18% of older subjects crawled at home. Eight percent of younger and 28% of older subjects used wheelchairs at school. Seventy-three percent to 75% of all subjects used strollers/wheelchairs in the community. IV-Sixty-two percent of younger and 43% of older subjects crawled at home. Approximately 15% of all subjects did some aided walking at home. Twenty-seven percent of younger children did some aided walking at school, while only 1 older subject did so. All used strollers/wheelchairs in the community. CONCLUSION: Mobility function varies within each GMFCS level with the most variability in GMFCS II at school and community distances and GMFCS III at household distances. These findings highlight the importance of using both the GMFCS and FMS when assessing functional mobility in children with CP. LEVEL OF EVIDENCE: Level III-retrospective study.

Calcaneal Sliding Osteotomy Versus Calcaneal Lengthening Osteotomy for Valgus Foot Deformity Correction in Children With Cerebral Palsy.

BACKGROUND: Medial calcaneal sliding (CS) osteotomy and lateral column lengthening (LCL) are often performed to relieve pain and improve transverse plane alignment and gait stability for children with cerebral palsy (CP) and valgus foot deformities. The purpose of this study was to examine the effectiveness of these procedures in this population. METHODS: Retrospective medical record review (including 3D gait analysis data) of patients with CP who underwent LCL (26 subjects, 46 limbs) or CS (46 subjects, 73 limbs). Data extraction included complications (modified Clavien-Dindo system), change in standing foot position (modified Yoo system), and change in gait kinematics and kinetics preoperatively to postoperatively. Groups were compared using paired t tests, Fisher exact test, and survivorship analysis using Cox proportional hazard models. RESULTS: Subjects were 57% male, average age at surgery 11.1 (SD 2.5) years. Average length of follow-up was 3.2 (SD 2.8) years, and was longer in the LCL group (P=0.0004). Complications were minor with similar rates between groups (P=0.14). Prolonged pain and plantar hypersensitivity occurred only in the CS group. Successful maintenance of deformity correction was achieved in 52/73 limbs (71%) in the CS group and 16/44 limbs (36%) in the LCL group (P<0.001). Recurrent pes valgus and need for repeat foot surgery were more common after LCL (P=0.003 and 0.001, respectively). Recurrent pes valgus never occurred when talonavicular fusion was done concomitantly with CS. After accounting for the between group difference in length of follow-up, there was no difference in the rates of recurrent valgus or repeat foot surgery between LCL and CS. None of the variables predicted development of pes varus (P>0.20). Ankle kinematics and kinetics during gait were unchanged in both groups. CONCLUSIONS: CS and LCL have similar effectiveness in providing long-lasting correction of valgus foot deformities. Concomitant talonavicular fusion is key to success of CS for lower functioning patients with severe deformities, and obligate brace wearers. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Rectus Femoris Transfer Surgery Worsens Crouch Gait in Children With Cerebral Palsy at GMFCS Levels III and IV.

BACKGROUND: Previous study has shown that children with cerebral palsy (CP) functioning at Gross Motor Function Classification System (GMFCS) levels III and IV do not benefit from distal rectus femoris transfer (DRFT) due to lack of improvement in stance knee extension. The fate of knees in such subjects who do not undergo DRFT is unknown. The purpose of this study was to compare knee kinematic outcomes in patients with CP and stiff knee gait who underwent single-event multilevel surgery with and without DRFT. METHODS: Preoperative and postoperative gait analysis data were retrospectively reviewed for ambulatory (GMFCS levels I to IV) patients with CP with crouch and stiff knee gait whom underwent single-event multilevel surgery, including hamstring lengthening either with DRFT (N=34) or without DRFT (N=40). Statistical analyses included t tests and χ tests, and multiple regression analysis was performed to adjust for covariates. Data were stratified by GMFCS level groups I/II and III/IV. RESULTS: Improved maximum knee extension in stance was seen for both the DRFT (P=0.0002) and no DRFT groups (P≤0.0006) at GMFCS levels I/II, and the no DRFT group at GMFCS levels III/IV (P=0.02). Excessive stance knee flexion persisted for those at GMFCS level III/IV after DRFT. Maximum knee flexion in swing was maintained after DRFT, but significantly decreased in the no DRFT group (P<0.002) for both GMFCS groups. Change in total knee range of motion improved after DRFT only in the GMFCS I/II group subjects with unilateral involvement (P=0.01). Timing of maximum knee flexion in swing improved for all patients regardless of DRFT or GMFCS level group (P<0.0001). CONCLUSIONS: In patients with CP functioning at GMFCS levels III and IV, DRFT results in persistent crouch postoperatively. Given the importance of maintaining upright posture in these patients, we do not recommend DRFT in patients functioning at GMFCS levels III and IV. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Prevalence of specific gait abnormalities in children with cerebral palsy revisited: influence of age, prior surgery, and Gross Motor Function Classification System level.

AIM: To examine the impact of age, surgery, and Gross Motor Function Classification System (GMFCS) level on the prevalence of gait problems in children with cerebral palsy (CP). METHOD: Gait analysis records were retrospectively reviewed for ambulatory patients with CP. Gait abnormalities were identified using physical exam and kinematic data. Relationships among age, sex, previous surgery, GMFCS level, and prevalence of gait abnormalities associated with crouch and out-toeing, and equinus and in-toeing were assessed using univariable and multivariable logistic regression. RESULTS: One-thousand and five records were reviewed. The most common gait problems were in-toeing, excessive knee flexion, stiff knee, hip flexion, internal rotation, adduction, and equinus (all >50%). Odds ratios (OR) for various gait problems associated with crouch and out-toeing increased (OR 1.07-1.32), and those associated with equinus and in-toeing decreased (OR 0.80-0.94) significantly with increasing age for patients in GMFCS levels I to III. The same trends were seen with prior surgery (OR for crouch and out-toeing: 1.86-7.14; OR for equinus and in-toeing: 0.16-0.59). INTERPRETATION: The prevalence of gait abnormalities varies by GMFCS level, but similarities exist among levels. The study results suggest that in younger children, particularly those in GMFCS levels III and IV, treatments for equinus and in-toeing should be undertaken with caution because these problems tend to decrease with age even without orthopedic intervention. Such children may end up with the 'opposite' deformities of calcaneal crouch and out-toeing, which tend to increase in prevalence with age.

Long-term ambulatory change after lower extremity orthopaedic surgery in children with cerebral palsy: a retrospective review.

BACKGROUND: Long-term studies of lower extremity orthopaedic surgery in children with cerebral palsy (CP) tend to focus on gait kinematics and kinetics, with little to no emphasis on gross motor ambulatory function. The current study was undertaken to examine the long-term impact of surgery on ambulatory function in patients with CP enrolled in a government-funded, outpatient therapy program. METHODS: Retrospective medical record review was conducted of 127 children with CP, Gross Motor Function Classification System (GMFCS) levels I to IV, followed up to 14 years after lower extremity orthopaedic surgery. Data were extracted from medical/operative records and routine physical therapy evaluations performed over the course of follow-up. Functional Mobility Scale (FMS) scores were assigned based on gross motor function information contained in each 6- to 12-month physical therapy evaluation. Data were compared statistically among GMFCS levels. RESULTS: Average length of follow up was 11.8±4 years. Subjects underwent 0.61±0.43 surgical procedures per person-year in 0.16±0.09 operative sessions per person-year with no differences between GMFCS levels. Subjects at GMFCS level I improved significantly in community (P=0.02) but not household ambulation, reflecting the ceiling effect of the FMS. Subjects at GMFCS levels II to IV showed statistically significant improvements at all distances. Subjects at level III gained more in household than long-distance ambulation (P=0.002). Subjects functioning at GMFCS level II improved by 1 FMS level for household and school distances, and 2 FMS levels for community distances (P<0.02). Subjects at level IV exhibited small ambulatory gains at all distances (P<0.04). CONCLUSIONS: Significant long-term improvement in functional ambulation is seen after surgery for children at all GMFCS levels. Children with more independence tend to make gains in long-distance ambulation, whereas those who use assistive devices tend to improve more in short-distance ambulation. This information may be useful to clinicians when counseling patients and their families regarding potential for ambulatory improvement after lower extremity orthopaedic surgery. LEVEL OF EVIDENCE: Level IV: case series.

Knee Pain and Patellofemoral Symptoms in Patients With Cerebral Palsy.

BACKGROUND: Knee pain in cerebral palsy (CP) is associated with increased patellofemoral forces present when walking with flexed knees. In typically developing children, knee pain and patellofemoral dysfunction are associated with obesity, genu valgum, femoral anteversion, and external tibial torsion. These problems are also common in CP, and may contribute to knee problems in this population. The purposes of this study were to define the prevalence of knee pain and patellofemoral dysfunction in children with CP, and to identify physical and gait characteristics (using 3-dimensional gait analysis data) that predispose them to such problems. METHODS: Retrospective review of 121 children with CP, Gross Motor Function Classification System level I to IV, who underwent computerized gait analysis testing. Demographics, range of motion, body mass index and hip, knee, and ankle kinematics were compared between subjects with and without knee pain. RESULTS: Twenty-five of 121 subjects (21%) reported knee pain at the time of testing. Three of 121 subjects (2%) had a history of patellar subluxation/dislocation. Age and sex were significantly related to presence of knee pain. The likelihood of knee pain was almost 5 times higher in females (odds ratio=4.9, [95% confidence interval, 1.8-13.3], P=0.002), with a prevalence of 40% (17/42) in females versus 10% (8/79) in males. The likelihood of knee pain increased with age by approximately 13% per year (odds ratio=1.13, [95% confidence interval, 1.00-1.28], P=0.058). Malignant malalignment syndrome showed a potential relationship to more severe knee pain (P=0.05), which warrants further investigation. Body mass index, pes valgus, and degree of stance knee flexion showed no statistically significant relationships to knee pain (P>0.16). CONCLUSIONS: The prevalence of knee pain in ambulatory patients with CP is approximately 21%. Patellar subluxation (2%) and dislocation are rare in these patients. Knee pain is not always related to crouch, femoral anteversion, external tibial torsion, genu valgum, or pes valgus. Knee pain in these patients is more prevalent in females, and increases with increasing age. LEVEL OF EVIDENCE: Level III-case-control study.

Comparison of 2 Orthotic Approaches in Children With Cerebral Palsy.

PURPOSE: To compare dynamic ankle-foot orthoses (DAFOs) and adjustable dynamic response (ADR) ankle-foot orthoses (AFOs) in children with cerebral palsy. METHODS: A total of 10 children with cerebral palsy (4-12 years; 6 at Gross Motor Function Classification System level I, 4 at Gross Motor Function Classification System level III) and crouch and/or equinus gait wore DAFOs and ADR-AFOs, each for 4 weeks, in randomized order. Laboratory-based gait analysis, walking activity monitor, and parent-reported questionnaire outcomes were compared among braces and barefoot conditions. RESULTS: Children demonstrated better stride length (11-12 cm), hip extension (2°-4°), and swing-phase dorsiflexion (9°-17°) in both braces versus barefoot. Push-off power (0.3 W/kg) and knee extension (5°) were better in ADR-AFOs than in DAFOs. Parent satisfaction and walking activity (742 steps per day, 43 minutes per day) were higher for DAFOs. CONCLUSIONS: ADR-AFOs produce better knee extension and push-off power; DAFOs produce more normal ankle motion, greater parent satisfaction, and walking activity. Both braces provide improvements over barefoot.

Update on the reliability of gait analysis interpretation in cerebral palsy: Inter-institution agreement.

BACKGROUND: Studies have shown good reliability for gait analysis interpretation among surgeons from the same institution. However, reliability among surgeons from different institutions remains to be determined. RESEARCH QUESTION: Is gait analysis interpretation by surgeons from different institutions as reliable as it is for surgeons from the same institution? METHODS: Gait analysis data for 67 patients with cerebral palsy (CP) were reviewed prospectively by two orthopedic surgeons from different institutions in the same state, each with > 10 years' experience interpreting gait analysis data. The surgeons identified gait problems and made treatment recommendations for each patient using a rating form. Percent agreement between raters was calculated for each problem and treatment, and compared to expected agreement based on chance using Cohen's kappa. RESULTS: For problem identification, the greatest agreement was seen for equinus (85% agreement), calcaneus (88%), in-toeing (89%), and out-toeing (90%). Agreement for the remaining problems ranged between 66-78%. Percent agreement was significantly higher than expected due to chance for all issues (p ≤ 0.01) with modest kappa values ranging from 0.12 to 0.51. Agreement between surgeons for treatment recommendations was highest for triceps surae lengthening (89% agreement), tibial derotation osteotomy (90%), and foot osteotomy (87%). Agreement for the remaining treatments ranged between 72-78%. Percent agreement for all treatments was significantly higher than the expected values (p ≤ 0.002) with modest kappa values ranging from 0.22 to 0.52. SIGNIFICANCE: Previous research established that computerized gait analysis data interpretation is reliable for surgeons within a single institution. The current study demonstrates that gait analysis interpretation can also be reliable among surgeons from different institutions. Future research should examine reliability among physicians from more institutions to confirm these results.

Impact of gait analysis on correction of excessive hip internal rotation in ambulatory children with cerebral palsy: a randomized controlled trial.

AIM: The aim of this study was to determine if gait analysis improves correction of excessive hip internal rotation in ambulatory children with spastic cerebral palsy (CP). METHOD: Children undergoing orthopedic surgery were randomized to receive or not receive a preoperative gait analysis report. This secondary analysis included all participants whose gait report recommended external femoral derotation osteotomy (FDRO). One-year postoperative, and pre- to postoperative change in femoral anteversion, mean hip rotation in stance, and mean foot progression in stance were compared between groups and in subgroups based on whether the recommendation for FDRO was followed. RESULTS: Outcomes did not differ between the group which received a gait report (n=39; 19 males, 20 females; mean age 10y 4mo [SD 3y]; hemiplegia, 3; di/triplegia, 28; quadriplegia, 8; Gross Motor Function Classification System [GMFCS]: level I, 5; level II, 12; level III 19; level IV, 3) and the control group (n=26; 14 males, 12 females; mean age 9y 5mo [SD 2y 10mo]; hemiplegia, 1; di/triplegia, 21; quadriplegia, 4; GMFCS: level I, 4; level II, 1; level III, 9; level IV, 2; all p values >0.29), but improved more in the gait report subgroup in which the FDRO recommendation was followed (seven limbs; change in anteversion -32.9°, hip rotation -25.5°, foot progression -36.2°) than in the control group (anteversion -12.2°, hip rotation -7.6°, foot progression -12.4°; all p values ≤0.02) and the gait report subgroup in which FDRO was not performed (32 limbs; anteversion -1.0°, hip rotation 0.5°, foot progression -8.0°; all p values ≤0.003). Postoperative measures became normal only in the gait report subgroup in which the recommended FDRO was performed. INTERPRETATION: Gait analysis can improve outcomes when its recommendations are incorporated in the treatment plan.

Transverse plane gait problems in children with cerebral palsy.

Transverse plane deviations are significant contributors to pathologic gait in children with cerebral palsy (CP). Due to limitations in neuromuscular control, balance, strength and coordination, transverse plane gait deviations are poorly tolerated in these children. Transverse plane malalignment results in lever arm dysfunction and can be seen with either intoeing or out-toeing. Frequent causes of transverse plane problems and lever arm dysfunction include long bone (femoral and/or tibial) torsion, pelvic rotation, and pes varus or valgus. Computerized motion analysis facilitates accurate identification of transverse plane abnormalities. This article addresses appropriate identification and treatment of transverse plane gait deviations in children with CP.

Repeat hamstring lengthening for crouch gait in children with cerebral palsy.

BACKGROUND: Progressive crouch gait occurs in patients with cerebral palsy with increasing age. Hamstring lengthening improves crouch in these patients, but hamstring contractures can recur over time. The purpose of this study was to determine whether revision hamstring lengthening is as effective as primary lengthening in improving crouched gait. METHODS: Retrospective review was performed for 39 patients with static encephalopathy, average age 10±4 years, who underwent hamstring lengthening. Twenty-one subjects underwent a single hamstring lengthening (HSL group), and 18 underwent repeat HSL (rHSL group). Range of motion (ROM) and kinematic measures from preoperative and postoperative gait analysis testing were compared within and between groups using t tests, χ2 tests, and multiple regression analyses as appropriate. RESULTS: A total of 15/21 subjects in the HSL group (71%) improved stance knee extension by ≥10 degrees, as compared with 5/18 (28%) in the rHSL group (P=0.007). The HSL group had improved popliteal angle, static knee and hip extension ROM, and knee flexion at initial contact and in stance phase (P<0.003). No such improvements were seen in the rHSL group. Popliteal angle, knee and hip extension ROM, and knee flexion at initial contact and in stance phase had significantly greater improvement in the HSL than the rHSL group (P<0.01). These differences persisted after adjusting for preoperative minimum hip flexion in stance, the only variable that differed between groups preoperatively. CONCLUSIONS: Repeat hamstring lengthening may delay progressive crouch, but does not result in long-term correction of crouch gait. Recurrent crouch may be caused by other factors such as quadriceps insufficiency, and may reflect the natural history of CP. Patients with recurrent crouch after hamstring lengthening are likely to benefit more from alternative surgical interventions to improve their knee position and function during gait. LEVEL OF EVIDENCE: Level IV-case series.

Comparison of kinematics between Theia markerless and conventional marker-based gait analysis in clinical patients.

BACKGROUND: Markerless motion capture systems have the potential to make clinical gait analysis more efficient and convenient. Theia3D is a commercially available markerless system that may serve as an alternative to traditional gait analysis for clinical gait laboratories. RESEARCH QUESTION: What is the concurrent validity of markerless gait analysis using Theia3D compared to traditional marker-based gait analysis in pediatric clinical gait patients? METHODS: Thirty-six patients (20 male, age 2-25 years) with a range of diagnoses underwent clinical gait analysis with data being captured concurrently by a traditional marker-based motion capture system (Vicon Nexus) and a commercial markerless system (Theia3D). Multiple left strides were averaged for each subject, and the difference in kinematics (Theia - Vicon) was calculated over the gait cycle and evaluated using root mean square difference (RMSD), mean difference, and RMSD after subtracting the mean value across the gait cycle (RMSDoffset). Sub-analysis was performed for 25 patients with foot deformities, 9 wearing ankle-foot orthoses, and 6 walking with assistance (cane, crutches, walker, or handheld). RESULTS: Kinematics showed similar patterns between the marker-based and markerless systems. RMSD was < 6° except for pelvic tilt, hip flexion, ankle inversion, foot progression, and transverse plane rotation of the hip, knee, and ankle. These measures mainly differed due to an offset between the curves. After adjusting for offsets, all RMSDoffset were < 6°. RMSD was larger for patients with foot deformities, wearing orthoses, or using assistive devices, but all RMSDoffset were still < 8°. In some cases, however, the markerless system had greater trial-to-trial variability, showed a larger knee varus "bump" in swing, or failed to track the subject. SIGNIFICANCE: This study provides preliminary evidence of concurrent validity of Theia3D for pediatric patients with abnormal gait. However, some questions remain regarding identification of the knee axis and for patients with foot deformity or assistive devices.

Predictors of Changes in Pelvic Rotation after Surgery with or without Femoral Derotational Osteotomy in Ambulatory Children with Cerebral Palsy.

Asymmetry of pelvic rotation affects function. However, predicting the post-operative changes in pelvic rotation is difficult as the root causes are complex and likely multifactorial. This retrospective study explored potential predictors of the changes in pelvic rotation after surgery with or without femoral derotational osteotomy (FDRO) in ambulatory children with cerebral palsy (CP). The change in the mean pelvic rotation angle during the gait cycle, pre- to post-operatively, was examined based on the type of surgery (with or without FDRO) and CP distribution (unilateral or bilateral involvement). In unilaterally involved patients, pelvic rotation changed towards normal with FDRO (p = 0.04), whereas patients who did not undergo FDRO showed a significant worsening of pelvic asymmetry (p = 0.02). In bilaterally involved patients, the changes in pelvic rotation did not differ based on FDRO (p = 0.84). Pelvic rotation corrected more with a greater pre-operative asymmetry (ß = -0.21, SE = 0.10, p = 0.03). Sex, age at surgery, GMFCS level, and follow-up time did not impact the change in pelvic rotation. For children with hemiplegia, internal hip rotation might cause compensatory deviation in pelvic rotation, which could be improved with surgical correction of the hip. The predicted changes in pelvic rotation should be considered when planning surgery for children with CP.

Persistent increase in anterior pelvic tilt after hamstring lengthening in children with cerebral palsy.

BACKGROUND: Hamstring lengthening has traditionally been the surgical treatment of choice to correct flexed knee gait in children with cerebral palsy (CP). Improved passive knee extension and knee extension during gait are reported post hamstring lengthening, but concurrent increased anterior pelvic tilt also occurs. RESEARCH QUESTION: Does anterior pelvic tilt increase after hamstring lengthening in children with CP both in the short-term and mid-term, and what predicts increased post-operative anterior pelvic tilt? METHODS: 44 participants were included (age 7.2, SD 2.0 years; 5 GMFCS I, 17 GMFCS II, 21 GMFCS III, 1 GMFCS IV). Mean pelvic tilt was compared between visits, and the effect of potential predictors of change in pelvic tilt was examined using linear mixed models. The relationship of change in pelvic tilt to change in other variables was examined using Pearson correlation. RESULTS: Anterior pelvic tilt increased significantly post-operatively by 4.8° (p < 0.001). It remained significantly higher by 3.8° at 2-15 years follow-up (p < 0.001). Change in pelvic tilt was not affected by sex, age at surgery, GMFCS level, assistance during walking, time since surgery, or baseline values of hip extensor strength, knee extensor strength, knee flexor strength, popliteal angle, hip flexion contracture, step length, walking speed, maximum hip power in stance, or minimum knee flexion in stance. Pre-operative dynamic hamstring length was associated with greater anterior pelvic tilt at all visits but did not affect amount of change in pelvic tilt. Patients in GMFCS I-II showed a similar pattern of change in pelvic tilt to GMFCS III-IV. SIGNFICANCE: When considering hamstring lengthening for ambulatory children with CP, surgeons should weigh increased mid-term anterior pelvic tilt post-operatively with the desired outcome of improved knee extension in stance. Patients with neutral or posterior pelvic tilt and short dynamic hamstring lengths pre-operatively have lowest risk of excessive post-operative anterior pelvic tilt.