[Acetabular plasty assisted by 3D printing for the treatment of dislocation of hip joint in children with cerebral palsy].

OBJECTIVE: To identify types of acetabular dysplasia, select the most suitable acetabular plasty, and analyze indications and efficacy of three types of acetabular plasty in treating dislocation of hip joint in children with cerebral palsy by 3D printing technology.

METHODS: From July 2019 to December 2019, 7 children with cerebral palsy with hip dislocation were treated with acetabular plasty assisted by 3D printing technology, including 3 males and 4 females, aged from 3 from 8 years old;3 patients on the left side, 2 patients on the right side, and 2 patients on both sides. Subluxation of hip joint occurred in 2 patients and dislocation of hip joint occurred in 5 patients. Preoperative full-length CT scan of pelvis and femur was performed in all children. The types of acetabular dysplasia were determined by 3D printing reconstruction technology, and the results were presented as follows:2 anterior hips, 2 anterior outer hips, 1 outer upper hip, 2 posterior hips, 1 posterior outer hip, and 1 hip without dysplasia(with no acetabular plasty). Pemberton, Dega and San Diego surgery simulations were performed on the 8 hips respectively to find the most suitable and the suitable operations were then conducted. Migration percentage (MP), acetabular index (AI) and cenal-edge angle (CEA), Shenton line, and gross motor function classification system(GMFCS) between preoperative and last follow-up were compared and complications were recorded.

RESULTS: The wound healed well after operation and no complication occurred. Seven patients were followed up for 18 to 24 months. The 8 hips were underwent soft tissue release for the first stage+proximal femoral varus and rotation reduction osteotomy+hip reduction+acetabular plasty;1 hip was underwent soft tissue release for the first stage+proximal femoral varus removal and rotation reduction osteotomy +hip reduction. MP decreased from 58% to 100% preoperatively to 0 to 17.9% at the latest follow-up. AI decreased from 25.0° to 47.6° preoperatively to 11.1° to 25.3° at the latest follow-up. CEA increased from 0° preoperatively to 21.1° to 48.5° at the latest follow-up. Shenton's lines changed from interrupted ones to continuous ones. The GMFCS grade of 5 cases decreased by 1 grade, and 2 cases showed no change.

CONCLUSION: There is diversity for the hip dislocation of hip in children with cerebral palsy of acetabular dysplasia present type. Accurate judgments could be made with the help of 3D printing reconstruction techniques. There are differences between scopes of applications for three kinds of acetabulum keratoplasty. 3D printing technology could be helpful to choose the most suitable operation method and estimate the treatment effect. Thus the individualized and accurate treatment for hip dislocation in children with cerebral palsy can be gained with 3D printing technology.