Hip problems are widespread among cerebral palsy sufferers, but they occur most frequently in patients with spastic cerebral palsy. Aside from hip deformation, hip displacement (subluxation and dislocation) is also common. Hip dysfunction is associated with limited motor function and, in some cases, with pain. It is sometimes possible to treat such hip dysfunction with certain surgical techniques, such as bone shortening or soft-tissue lengthening.
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BACKGROUND: Hip displacement is considered to be common in children with cerebral palsy but the reported incidence and the proposed risk factors vary widely. Knowledge regarding its overall incidence and associated risk factors can facilitate treatment of these children. METHODS: An inception cohort was generated from the Victorian Cerebral Palsy Register for the birth years 1990 through 1992, inclusive, and multiple data sources pertaining to the cohort were reviewed during 2004. Gross motor function was assessed for each child and was graded according to the Gross Motor Function Classification System (GMFCS), which is a valid, reliable, five-level ordinal grading system. Hip displacement, defined as a migration percentage of >30%, was measured on an anteroposterior radiograph of the pelvis with use of a reliable technique. RESULTS: A full data set was obtained for 323 (86%) of 374 children in the Register for the birth years 1990 through 1992. The mean duration of follow-up was eleven years and eight months. The incidence of hip displacement for the entire birth cohort was 35%, and it showed a linear relationship with the level of gross motor function. The incidence of hip displacement was 0% for children with GMFCS level I and 90% for those with GMFCS level V. Compared with children with GMFCS level II, those with levels III, IV, and V had significantly higher relative risks of hip displacement (2.7, 4.6, and 5.9, respectively). CONCLUSIONS: Hip displacement is common in children with cerebral palsy, with an overall incidence of 35% found in this study. The risk of hip displacement is directly related to gross motor function as graded with the Gross Motor Function Classification System. This information may be important when assessing the risk of hip displacement for an individual child who has cerebral palsy, for counseling parents, and in the design of screening programs and resource allocation.
[Soo, B., Howard, J. J., Boyd, R. N., Reid, S. M., Lanigan, A., Wolfe, R., Reddihough, D. & Graham, H. K. (2006). Hip displacement in cerebral palsy. The Journal of Bone and Joint Surgery. American Volume, 88(1), 121-9.]
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BACKGROUND: The reported prevalence of hip pain in patients with severe cerebral palsy has varied widely. It is unclear whether surgical treatment is indicated for progressive hip subluxation in immature patients with severe involvement. In the present study, we evaluated seventy-seven adults who were profoundly affected with cerebral palsy to determine if either spastic hip displacement (subluxation or dislocation) or osteoarthritis was associated with hip pain and/or diminished function. METHODS: Data regarding the medical history, level of function, pain, and use of analgesics were obtained from a review of medical records and from caregiver interviews. The range of motion of the hip, the degree of spasticity, the presence of pressure ulcers, and changes in vital signs as well as in the Face, Legs, Activity, Cry, and Consolability behavioral pain score were documented. Radiographs of the pelvis and spine were blindly evaluated for evidence of osteoarthritis and subluxation or dislocation. Statistical analysis was performed in order to identify associations between the medical history, the physical examination findings, and the radiographic measurements. RESULTS: The study group included seventy-seven adult subjects (thirty-eight men and thirty-nine women) with a mean age of forty years. Twenty-three (15%) of the 154 hips in these subjects were dislocated, eighteen (12%) were subluxated, and thirty-five (23%) had radiographic evidence of osteoarthritis. Twenty-eight (18%) of the 154 hips were definitely painful, and sixty-nine (45%) were definitely not painful. Increased hip pain and problems with perineal care were noted in patients with decreased hip abduction (<30 degrees ) (p = 0.01), windswept hip deformities (p = 0.02), and flexion contractures of >30 degrees (p = 0.07). Increased spasticity was associated with higher rates of osteoarthritis, dislocation, pain, and pressure ulcers. Spastic hip subluxation or dislocation was significantly associated with osteoarthritis (p = 0.0001), but not with hip pain. There was no association between radiographic evidence of osteoarthritis and hip pain. CONCLUSIONS: Neither hip displacement (i.e., subluxation or dislocation) nor osteoarthritis was found to be associated with hip pain or diminished function. Because the prevalence of hip pain is low and is not associated with hip displacement or osteoarthritis, we suggest that surgical treatment of the hip in severely affected patients be based on the presence of pain or contractures and not on radiographic signs of hip displacement or osteoarthritis. LEVEL OF EVIDENCE: Prognostic study, Level II-1 (retrospective study). See Instructions to Authors for a complete description of levels of evidence.
[Noonan, K. J., Jones, J., Pierson, J., Honkamp, N. J. & Leverson, G. (2004). Hip function in adults with severe cerebral palsy. The Journal of Bone and Joint Surgery. American Volume, 86-A(12), 2607-13.]
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The prevalence of hip subluxation and dislocation in cerebral palsy ranges between 3% and 75% in the literature. Clinical signs are rigidity, pain and instability. We assessed functionality, stability and symptoms in 20 patients preoperatively and after follow-up. A varus derotation osteotomy was performed in cases with subluxation or dislocation, while a Chiari osteotomy was performed in the presence of a concomitant acetabular dysplasia. Results were good in 64%, fair in 22% and poor in 14% of patients treated with a varus derotation osteotomy. In patients treated with a Chiari osteotomy, results were good in 43% of cases, fair in 43% and poor in 14%. Subluxated or dislocated hips generally show several anomalies: their severity is directly proportional to the degree of neurological impairment. In the most severe cases, correction of just one of such anomalies might not be sufficient to guarantee good results of the surgery.
[Persiani, P., Molayem, I., Calistri, A., Rosi, S., Bove, M. & Villani, C. (2008). Hip subluxation and dislocation in cerebral palsy: Outcome of bone surgery in 21 hips. Acta Orthopaedic Belgica, 74(5), 609-14.]
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Hip dislocation in children with cerebral palsy is caused by a combination of factors, including spastic muscle imbalance, persistent fetal femoral geometry, acetabular dysplasia, and flexion-adduction contracture. The incidence of dislocation correlates with the severity of the spasticity, and the prevalence is close to 50% in neurologically immature, spastic quadriplegic children. Successful hip reductions improve muscular balance, provide satisfactory reduction of the femoral head, and establish good pelvic coverage. In 31 occurrences of established hip dislocation in 24 patients, the most successful operations used a combined procedure consisting of soft-tissue release, open reduction, femoral varus derotation and shortening osteotomy, and pelvic osteotomy.
[Gamble, J. G., Rinsky, L. A. & Bleck, E. E. (1990). Established hip dislocations in children with cerebral palsy. Clinical Orthopaedics and Related Research, 253, 90-9.]
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BACKGROUND: Hip dislocation in children with cerebral palsy (CP) is a common and severe problem. The dislocation can be avoided, by screening and preventive treatment of children with hips at risk. The aim of this study was to analyse the characteristics of children with CP who develop hip displacement, in order to optimise a hip surveillance programme. METHODS: In a total population of children with CP a standardised clinical and radiological follow-up of the hips was carried out as a part of a hip prevention programme. The present study is based on 212 children followed until 9-16 years of age. RESULTS: Of the 212 children, 38 (18%) developed displacement with Migration Percentage (MP) >40% and further 19 (9%) MP between 33 and 39%. Mean age at first registration of hip displacement was 4 years, but some hips showed MP > 40% already at two years of age. The passive range of hip motion at the time of first registration of hip displacement did not differ significantly from the findings in hips without displacement.The risk of hip displacement varied according to CP-subtype, from 0% in children with pure ataxia to 79% in children with spastic tetraplegia. The risk of displacement (MP > 40%) was directly related to the level of gross motor function, classified according to the gross motor function classification system, GMFCS, from 0% in children in GMFCS level I to 64% in GMFCS level V. CONCLUSION: Hip displacement in CP often occurs already at 2-3 years of age. Range of motion is a poor indicator of hips at risk. Thus early identification and early radiographic examination of children at risk is of great importance. The risk of hip displacement varies according to both CP-subtype and GMFCS. It is sometimes not possible to determine subtype before 4 years of age, and at present several definitions and classification systems are used. GMFCS is valid and reliable from 2 years of age, and it is internationally accepted.We recommend a hip surveillance programme for children with CP with radiographic examinations based on the child's age and GMFCS level.
[Hagglund, G., Lauge-Petersen, H. & Wagner, P. (2007). Characteristics of children with hip displacement in cerebral palsy. BMC Musculoskeletal Disorders, 8, 101.]
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BACKGROUND: The aims of the present study were to assess the development of hip dysplasia in children with bilateral spastic cerebral palsy and to evaluate the factors that influence the progression. PATIENTS AND METHODS: 76 children, 42 with spastic quadriplegia and 34 with diplegia, were included in the study. Their mean age at the first radiographic examination was 3.5 (1-11) years. The patients were followed up until operative treatment (54 subjects) or until the most recent radiograph in those who did not undergo hip surgery. The mean length of follow-up was 4.8 (1-13) years. On the initial and most recent radiographs, the migration percentage (MP) was measured, which is the percentage of the femoral head lateral to the acetabular rim. RESULTS: The mean MP of the side with the largest displacement was 25% (-18-66) at the initial radiographic examination and 51% (9-100) at the last follow-up. The mean increase in MP was 7% (-2-33) per year. Linear multiple regression revealed that gait function and age were the most important variables that influenced the rate of MP progression. Children who could not walk had significantly greater MP progression per year (12%) than those who walked with or without support (2%). In the quadriplegics, the maximal yearly increase in MP was 13% under 5 years of age and 7% in older children. This difference was statistically significant, whereas no significant difference in relation to patient age was seen in the diplegics. INTERPRETATION: There is a pronounced trend towards displacement of the hips in quadriplegic CP patients who are under 5 years of age and cannot walk. Because hip dislocation may lead to severe problems, close follow-up is important in finding the appropriate time for hip surgery in order to avoid progression towards dislocation. The risk of severe hip dysplasia is considerably less in spastic diplegia.
[Terjesen, T. (2006). Development of the hip joints in unoperated children with cerebral palsy: A radiographic study of 76 patients. Acta Orthopaedica, 77(1), 125-31.]
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The aim of this study was to assess the rate of hip dislocation at different ages in children with bilateral spastic cerebral palsy attending special schools in southern Derbyshire, UK, between 1985 and 2000. The medical notes of 110 individuals (68 males, 42 females) were obtained. They were divided into four groups according to the Gross Motor Function Classification System (GMFCS). We determined whether or not their hips were dislocated at the ages of 5, 10, and 15 years, and the kind of surgery performed in each case. The percentage of individuals with one or both hips dislocated increased with age and with severity of disease. Of those in GMFCS Level II (n=18), none had dislocations; Level III (n=16), none had dislocations at ages 5 and 10, but 11% had by the age of 15; Level IV (n=35), 8% had dislocations by age 5, 19% by age 10, and 30% by age 15; Level V (n=41), 22% had dislocations by age 5, 48% by age 10, and 50% by age 15. Forty-two per cent of individuals with hip dislocation had not had previous preventive surgery. Twenty-one per cent of hips operated on still proceeded to dislocation. We conclude that there was a high rate of hip dislocation, especially in GMFCS groups Levels IV and V, and that this often occurred very early. Preventive surgery avoided dislocation in many children. However, orthopaedic referral was often not made before dislocation was discovered, or the referral was made too late for surgery on soft tissue to be successful. These results may be compared with those from current programmes of hip management, involving radiological surveillance and early use of conservative and surgical interventions.
[Morton, R. E., Scott, B., McClelland, V. & Henry, A. (2006). Dislocation of the hips in children with bilateral spastic cerebral palsy, 1985-2000. Developmental Medicine and Child Neurology, 48(7), 555-8.]
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Mechanical factors have a strong influence on the development of the musculoskeletal system. Muscle forces are one of the most important sources of the loadings acting on the bone elements and any disturbances in their activity can lead to severe pathology. Cerebral palsy is an example of such a situation and hip joint deformity, leading to its dislocation, is one of the most serious complications accompanied with muscle spasticity. The aim of the study is to perform an analysis of the stress and strain in hip joint of the children with the imbalance in muscle forces due to adductors spasticity (overactivity). Finite element model has been developed based on anatomical data obtained from computer tomography. The results of numerical simulations show an increase in stress and strain occurring in the femoral head and acetabulum as well as some relocation of its concentration zone in the medial direction.
[Piszczatowski, S. (2008). Analysis of the stress and strain in hip joint of the children with adductors spasticity due to cerebral palsy. Acta of Bioengineering and Biomechanics, 10(2), 51-6.]
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Hip disorders are common in patients with cerebral palsy and cover a wide clinical spectrum, from the hip at risk to subluxation, dislocation, and dislocation with degeneration and pain. Although the hip is normal at birth, a combination of muscle imbalance and bony deformity leads to progressive dysplasia. The spasticity or contracture usually involves the adductor and iliopsoas muscles; thus, the majority of hips subluxate in a posterosuperior direction. Many patients with untreated dislocations develop pain by early adulthood. Because physical examination alone is unreliable, an anteroposterior radiograph of the pelvis is required for diagnosis. Soft-tissue lengthening is recommended for children as soon as discernable hip subluxation (hip abduction <30 degrees, migration index >25%) is recognized. One-stage comprehensive hip reconstruction is effective treatment for children 4 years of age or older who have a migration index >60% but who have not yet developed advanced degenerative changes of the femoral head. Salvage options for the skeletally mature patient with a neglected hip are limited.
[Flynn, J. M. & Miller, F. (2002). Management of hip disorders in patients with cerebral palsy. The Journal of the American Academy of Orthopaedic Surgeons, 10(3), 198-209.]
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OBJECTIVES: Hip subluxation and dislocation in patients suffering from cerebral palsy (CP) develop in response to a muscle imbalance, caused by contracture of hip adductors and flexors. In the radiological measurement of hip joint instability, the Reimers migration percentage and migration index is used. These methods are useful in planning soft tissue or bony surgery and also for the post operative follow up. PATIENTS AND METHODS: Authors evaluated 15 spastic patients with spastic tetra and di-plegia with 19 dislocated hips who underwent one stage hip reconstruction between 1995-2000. At one stage surgery, adductor tenotomy, capsulotomy, iliopsoas tenotomy, shortening varus (rotation) femoral osteotomy and pelvic osteotomy was performed. RESULTS: Complete stability was obtained in 16 hips with neither redislocation nor subluxation. The mean MP was 11.5% at the 5 year follow up. In one patient, a bilateral proximal femoral resection due to painful hips was performed later. None of the patients showed evidence of AVN. CONCLUSION: Hip instability leading to subluxation or dislocation is a serious problem in children suffering from CP and is usually worse in severe condition. Once subluxation or dislocation occurs, muscle releases should be combined with varus and shortening osteotomy. In an acetabular insufficiency, pelvic osteotomy is necessary to obtain the stability (Tab. 1, Ref 2, Ref 8).
[Kokavec, M. (2007). Evaluation and treatment of hip joint instability in patients with cerebral palsy. Bratislavske Lekarske Listy, 108(9), 406-8.]
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Dislocation of the hip associated with cerebral motor disturbances differs considerably from that in children with normal motor activity. In patients with such disturbances ist is a relatively common and often serious complication. It occurs at an age when there are not usually any clear spastic signs, merely hypotonia with reflex-like movement patterns. Early dislocation is marked by early onset of acetabular dysplasia. In the final analysis, hip dislocation associated with cerebral motor disturbances is attributable to a more or less constant muscle imbalance. The prognosis for hip development is poor if there is an early tendency toward flexion and adduction postures and the course of general motor development is unfavorable. The classification proposed by Tönnis and Brunken (1968) is used for radiological assessment. The primary goal of therapy is to prevent further decentration of the hip joint. Therefore, physiotherapy plays the most important role in early treatment of impending dislocation. All other therapeutic measures are secondary to this.
[Matthiass, H. H. (1990). Hip changes in infantile cerebral palsy [German]. Zeitschrift fur Orthopadie und ihre Grenzgebiete, 128(4), 373-6.]
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