Hip Displacement After Triradiate Closure in Ambulatory Cerebral Palsy: Who Needs Continued Surveillance?

BACKGROUND: Hip surveillance in cerebral palsy (CP) is an accepted practice with evidence-based guidelines implemented. For the skeletally immature with open triradiate cartilage (TRC), recommendations for radiographic surveillance stemmed from population-based studies. For nonambulatory CP, progression of hip displacement after skeletal maturity has been reported; less is known for ambulatory CP. We aimed to determine the prevalence and risk factors associated with progressive hip displacement after TRC closure, a proxy for skeletal maturity, for ambulatory CP. METHODS: This is a retrospective cohort study of patients with ambulatory CP (Gross Motor Function Classification System I-III), with unilateral or bilateral involvement, hypertonic motor type, regular hip surveillance (≥3 radiographs after age 10 yr, 1 before TRC closure, ≥1 after age 16 yr), and 2-year follow-up post-TRC closure. The primary outcome was migration percentage (MP). Other variables included previous preventative/reconstructive surgery, topographic pattern, sex, scoliosis, epilepsy, and ventriculoperitoneal shunt. An "unsuccessful hip" was defined by MP ≥30%, MP progression ≥10%, and/or requiring reconstructive surgery after TRC closure. Statistical analyses included chi-square and multivariate Cox regression. Kaplan-Meier survivorship curves were also determined. Receiver operating characteristic analysis was used to determine the MP threshold for progression to an "unsuccessful hip" after TRC closure. RESULTS: Seventy-six patients (39.5% female) met the inclusion criteria, mean follow-up 4.7±2.1 years after TRC closure. Sixteen (21.1%) patients had an unsuccessful hip outcome. By chi-square analysis, diplegia (P=0.002) and epilepsy (P=0.04) were risk factors for an unsuccessful hip. By multivariate analysis, only first MP after TRC closure (P<0.001) was a significant risk factor for progression to an unsuccessful hip; MP ≥28% being the determined threshold (receiver operating characteristic curve analysis, area under curve: 0.845, P<0.02). CONCLUSIONS: The risk of MP progression after skeletal maturity is relatively high (21%), similar to nonambulatory CP. Annual hip surveillance radiographs after TRC closure should continue for Gross Motor Function Classification System I-III with an MP ≥28% after TRC closure, especially for bilateral CP and epilepsy. LEVEL OF EVIDENCE: III.

The Etiology of Neuromuscular Hip Dysplasia and Implications for Management: A Narrative Review.

This study summarizes the current knowledge of the etiology of hip dysplasia in children with neuromuscular disease and the implications for management. This article is based on a review of development of the hip joint from embryology through childhood growth. This knowledge is then applied to selective case reviews to show how the understanding of these developmental principles can be used to plan specific treatments. The development of the hip joint is controlled by genetic shape determination, but the final adult shape is heavily dependent on the mechanical environment experienced by the hip joint during growth and development. Children with neuromuscular conditions show a high incidence of coxa valga, hip dysplasia, and subluxation. The etiology of hip pathology is influenced by factors including functional status, muscular tone, motor control, child's age, and muscle strength. These factors in combination influence the development of high neck-shaft angle and acetabular dysplasia in many children. The hip joint reaction force (HJRF) direction and magnitude determine the location of the femoral head in the acetabulum, the acetabular development, and the shape of the femoral neck. The full range of motion is required to develop a round femoral head. Persistent abnormal direction and/or magnitude of HJRF related to the muscular tone can lead to a deformed femoral head and a dysplastic acetabulum. Predominating thigh position is the primary cause defining the direction of the HJRF, leading to subluxation in nonambulatory children. The magnitude and direction of the HJRF determine the acetabular shape. The age of the child when these pathomechanics occur acts as a factor increasing the risk of hip subluxation. Understanding the risk factors leading to hip pathology can help to define principles for the management of neurologic hip impairment. The type of neurologic impairment as defined by functional severity assessed by Gross Motor Function Classification System and muscle tone can help to predict the risk of hip joint deformity. A good understanding of the biomechanical mechanisms can be valuable for treatment planning.

Prevalence and Treatment of Surgical Complications Following Proximal Femoral Osteotomies in Children with Cerebral Palsy: An Analysis of 1085 Hips.

Purpose: Proximal femoral osteotomy (PFO) is a reconstructive surgical option used to improve hip containment or correct internal hip rotation gait in children with cerebral palsy (CP). A few reports describe the risk of surgical complications after PFO. The purpose of this study was to determine the risk factors associated with adverse postoperative surgical outcomes in pediatric patients with CP following PFO and to report the treatment of complications. Methods: Following institutional review board approval, 1085 (1003 primary and 82 secondary) PFO procedures were retrospectively reviewed in 563 children with CP with at least 1 year of follow-up after final surgery over an 18-year follow-up period. Demographic characteristics, motor type, gross motor function classification system (GMFCS) level, medical comorbidities, feeding tube status, seizure history, intervention type, and prevalence of PFO-related surgical complications and associated treatments were evaluated. Multivariate regression analysis was performed to determine risk factors for all surgical complications. Results: During a 5.8-year (± 3.8 years) follow-up, at least 1 surgical complication was identified in 143 (13.1%) hips in 121 (21.5%) patients after PFO in children with CP. Of these complications, the most common was heterotopic ossification (65 [6%] of hips); most of which were asymptomatic and required no treatment. Other complications included 25 (2%) nonunions, 21 (2%) deep or superficial infections, 13 (1%) delayed unions, 12 (1%) peri-implant fractures, and 7 early implant failures (0.64). The rate of revision surgery due to these complications was 13.1% (6.8% of hips), of which 41% (30 revision surgeries) were for the treatment of nonunion. Regarding the development of delayed union or nonunion, dystonia, GMFCS level IV/V, and seizure history were identified as risk factors by multivariate analysis. Conclusions: The prevalence of surgical complications after PFO was 13.1% with 6.8% of hips requiring revision surgery. Dystonia, seizure history, and nonambulatory status were the strongest predictors for the need for revision surgery after PFO. These data can be used to help counsel patients and families regarding the risks associated with PFO for children with CP.Level of proof: IV; retrospective study.

The impact of hamstring lengthening on stance knee flexion at skeletal maturity in ambulatory cerebral palsy.

This study reports the long-term outcomes of hamstring lengthening to treat flexed knee gait in children with ambulatory cerebral palsy (CP) after skeletal maturity. This retrospective longitudinal observational study used instrumented gait analysis (GA) <8 and >15 years old in children with bilateral CP. The primary variable was knee flexion in stance phase. Eighty children (160 limbs) were included; 49% were male, 51% female. Mean age at first GA was 6.0 (SD: 1.2) years and 19.6 (SD: 4.5) years at final GA. Mean follow-up was 13.7 (SD: 4.7) years. Children were classified as Gross Motor Function Classification System I-8, II-46 and III-26. Average Gross Motor Function Measure Dimension D was 72% (SD: 20%). Hamstring lengthenings occurred once in 82, twice in 54 and three times in 10 limbs. From initial to final GA, average knee flexion in stance was unchanged, 27.8° (SD: 14.8°) to final 27.0° (SD: 11.2°; P = 0.54). Knee flexion at foot contact was 39.6° (SD: 13.0°), improving to final GA of 30.7° (SD: 10.6°; P < 0.001). Initial gait deviation index was 65.8 (SD: 31.9), improving to final 78.9 (SD: 28.2; P < 0.001). Older age, males and concomitant plantar flexor lengthening predicted change toward more flexed knee gait. Hamstring lengthening did not lead to back-kneeing gait at maturity while maintaining childhood stance phase knee flexion. A subgroup still developed significant flexed knee gait posture and may have benefited from more aggressive treatment options. This outcome may also be impacted by diverse functional levels, etiologies and treatments of flexed knee gait.

Changes in foot posture evaluated with dynamic pedobarography over the course of childhood in ambulatory youth with cerebral palsy.

Purpose: Foot deformities are prevalent in children with cerebral palsy, but there is limited research on the progression of foot posture during growth. Our study aimed to evaluate the change in dynamic foot posture in children with cerebral palsy. Methods: Children with cerebral palsy, aged 17-40 months, were recruited to participate in this Institutional Review Board-approved prospective longitudinal study by having serial foot posture evaluations. The coronal plane index and foot segmental impulses were measured with dynamic pedobarography. Data were compared between children stratified by Gross Motor Function Classification System level and typically developing children using serial Welch's t-tests across time with Holm correction for multiple comparisons. Results: In total, 33 children (54 limbs) were included in the analysis (21 bilateral and 12 unilateral; Gross Motor Function Classification System: I-13, II-14, III-4, IV-2. Children completed 16.9 (± 4.4) evaluations (initial age 2.9 (± 0.7) and final age 18.6 (± 1.7) years)). Early valgus foot posture normalizes in children at Gross Motor Function Classification System levels I/II and persists in children at levels III/IV who do not have foot surgery. For most young children, foot posture development is variable. Conclusion: Foot posture in young children with cerebral palsy begins in valgus and tends to normalize in youth who walk without an assistive device. Conservative management of foot deformity is recommended in early childhood. Level of evidence: Level II, prognostic study.

Self-reported Health-related Quality of Life in Adolescents With Cerebral Palsy.

BACKGROUND: Happiness, comfort, and motor function contribute to satisfaction with life for individuals with cerebral palsy (CP). Evidence-based medical care can improve motor function and physical health of youth with CP. Less is known about medical care and its relationship to health-related quality of life (HRQOL) in adolescents and young adults with CP. This study aimed to describe HRQOL among adolescents with CP to examine differences between adolescent (self) and parent (proxy) reports of HRQOL and to explore associations of pain, age, and gross motor function with HRQOL. METHODS: This is a retrospective study including adolescents with CP classified as Gross Motor Function Classification System levels I to V, ages 11 to 20 years, reading ≥ a fourth-grade level, and who completed the self-reported Pediatric Outcomes Data Collection Instrument (PODCI). Parents completed the PODCI concurrently or within 12 months and scores were compared. In addition, self-reported scores were compared between age bands, across Gross Motor Function Classification System levels, with typically developing youth (TDY), and between youth with/without pain. RESULTS: PODCI scores from 102 adolescents [59 males; 15.0 (SD: 2.6) years old] were examined. Scores from 50 adolescents and parents were matched. Mean self-reported scores were significantly higher than mean parent-reported scores in 4 domains: upper extremity and physical function ( P =0.018), sports and physical function ( P =0.005), happiness ( P =0.023), and global functioning ( P =0.018). All domains, except Happiness, were significantly < TDY ( P <0.01). The presence of pain was associated with lower scores in all domains ( P <0.05). CONCLUSION: Examining HRQOL with the PODCI revealed significant limitations in physical function and higher pain in adolescents with CP compared with TDY. Self- and parent-reported PODCI results should be considered separately. Adolescents report higher HRQOL compared with parent proxy. Recognizing and validating the perspectives of youth and their parents presents an opportunity for providers to discuss different points of view with families. Such engagement can help promote self-efficacy in youth with CP as they transition to the responsibility of guiding their own care in adulthood. LEVEL OF EVIDENCE: III, Retrospective comparative study.

Bone alterations of pamidronate therapy in children with cerebral palsy complicating orthopedic management.

Cerebral palsy (CP) is a heterogeneous group of disorders with different clinical types and underlying genetic variants. Children with CP are at risk for fragility fractures secondary to low bone mineral density, and although bisphosphonates are prescribed for the treatment of children with bone fragility, there is limited information on long-term bone impact and safety. Children with CP usually present overtubulated bones, and the thickening of cortical bone by pamidronate treatment can potentially further narrow the medullary canal. Our purpose was to report bone alterations attributable to pamidronate therapy that impact orthopedic care in children with CP. The study consisted of 41 children with CP treated with pamidronate for low bone mineral density from 2006 to 2020. Six children presented unique bone deformities and unusual radiologic features attributed to pamidronate treatment, which affected their orthopedic care. The cases included narrowing of the medullary canal and sclerotic bone, atypical femoral fracture, and heterotopic ossification. Treatment with bisphosphonate reduced the number of fractures from 101 in the pretreatment period to seven in the post-treatment period (P < 0.001). In conclusion, children with CP treated with bisphosphonate have a reduction in low-energy fractures; however, some fractures still happen, and pamidronate treatment can lead to bone alterations including medullary canal narrowing with sclerotic bone and atypical femoral fractures. In very young children, failure to remodel may lead to thin, large femoral shafts with cystic medullary canals. More widespread use of bisphosphonates in children with CP may make these bone alterations more frequent. Level of evidence: Level IV: Case series with post-test outcomes.

Identification of risk factors for reconstructive hip surgery after intrathecal baclofen therapy in children with cerebral palsy.

OBJECTIVE: This study aimed to determine the risk factors for reconstructive hip surgery after intrathecal baclofen pump application in children with cerebral palsy. METHODS: Inclusion criteria were children with hypertonic (spastic or mixed spastic/dystonic motor type) cerebral palsy, intrathecal baclofen implantation <8 years of age, no reconstructive osteotomies prior to or concomitant with intrathecal baclofen implantation and at least a 5-year follow-up. Exclusion criteria included reconstructive osteotomies prior to or concurrent with intrathecal baclofen implantation, lack of at least 1 hip surveillance radiograph before intrathecal baclofen, lack of a 5-year follow-up, or having selective dorsal rhizotomy. In addition, patients with bony surgery plus last follow-up migration percentage ≥50% were labeled as required reconstruction hips. RESULTS: We identified 34 patients (68 hips). The mean follow-up was 9.2 ± 2.8 years. The mean age for intrathecal baclofen application was 6.4 ± 1.2 years. Seven patients were Gross Motor Function Classification System IV, and 27 were V. Eighteen patients (52.9%) with 31 hips (45.6%) were requiring reconstruction at the final follow-up. In multivariate analysis, male sex (odds ratio 12.8, P=.012), pre-intrathecal baclofen migration percentage (odds ratio 1.1, P=0.003), age at intrathecal baclofen implantation (odds ratio 0.24, P=.002), and delta migration percentage (odds ratio 1.1, P=.002) were significant risk factors for requiring reconstruction. Patients with intrathecal baclofen <6.2 years of age had a significantly higher rate of requiring reconstruction. A pre-intrathecal baclofen migration percentage >31% had a greater risk of progression to requiring reconstruction (P=.001). Delta migration percentage higher than 15% was significantly associated with progression to requiring reconstruction (P=.043). CONCLUSION: The risk of requiring reconstruction osteotomies after intrathecal baclofen was significantly increased in males, those younger (±migration percentage >31%) at the time of intrathecal baclofen implantation and those with an increased rate of migration percentage progression after intrathecal baclofen implantation. LEVEL OF EVIDENCE: Level IV, Prognostic Study.

Mortality after spinal fusion in children with cerebral palsy and cerebral-palsy-like conditions: A 30-year follow-up study.

AIM: To report survival probability of a large cohort of children with cerebral palsy (CP) after spinal fusion. METHOD: All children with CP who had spinal fusion between 1988 and 2018 at the reporting facility were reviewed for survival. Death records of the institutional CP database, institutional electronic medical records, publicly available obituaries, and the National Death Index through the US Centers for Disease Control were searched. Survival probabilities with different surgical eras, comorbidities, ages, and curve severities were compared using Kaplan-Meier curves. RESULTS: A total of 787 children (402 females, 385 males) had spinal fusion at a mean age of 14 years 1 month (standard deviation 3 years 2 months). The 30-year estimated survival was approximately 30%. Survival decreased for children who had spinal fusion at younger ages, longer postoperative hospital stays, longer postoperative intensive care unit stays, gastrostomy tubes, and pulmonary comorbidities. INTERPRETATION: Children with CP who required spinal fusions had reduced long-term survival compared with an age-matched typically developing cohort; however, a substantial number survived 20 to 30 years after the surgery. This study had no comparison group of children with CP scoliosis; therefore, we do not know whether correction of scoliosis affected their survival.