Incidence and risk factors of hip joint pain in children with severe cerebral palsy.

PURPOSE

Pain is a serious complication associated with hip dislocation in cerebral palsy (CP), limiting patient independence and quality of life. This study aimed to determine the frequency of pain in severe CP patients with hip dislocation and to reveal factors associated with the hip pain.

METHODS

Seventy-three consecutive new-intervention CP patients admitted to authors' institution with spastic quadriplegia, mean age 10.8 years (range 4.0-18.0 years) were enrolled: 31 females and 42 males, totally 99 dislocated hips. All patients were assessed level IV or V according to the Gross Motor Function Classification Scale (GMFCS) and had poor communication skills. Pain severity was evaluated according to the Numeric Rating Scale (NRS-11). Data concerning previously applied physiotherapy was collected to divide the patients into subgroups: A - no abduction therapy (n = 24), B - abduction therapy (n = 35) and C - abduction therapy and horse-back riding (n = 13). On the pelvic antero-posterior radiographs head migration percentage was measured to reveal hip dislocation. Femoral head cartilage degenerative lesions were evaluated for size and location in 45 hips undergoing surgical treatment.

RESULTS

Overall pain prevalence was 56%. The appearance of pain was associated with the patient age (p = 0.048), previous abduction physiotherapy (p < 0.00001), previous horse-back riding therapy (p < 0.00001) and anterior location of degenerative changes of the femoral head (p = 0.03). Pain intensity was related to the size of the degenerative cartilage lesions (p = 0.004) and to the degree of femoral anteversion (p < 0.0001).

CONCLUSIONS

Extensive abduction exercises, hippotherapy and presence of degenerative cartilage lesions on the anterior part of femoral head may be considered risk factors for hip pain appearance in the dislocated hip of a child with severe spastic CP. Other associated factors are abduction exercise intensity, age, excessive femoral anteversion and size of degenerative cartilage lesions.