Foam splint versus spica cast - Early mobilization after hip reconstructive surgery in children - A prospective randomized clinical trial
Authors: Pisecky Lorenz , Großbötzl Gerhard , Allerstorfer Jakob , Bruckner Thomas , Horsch Axel , Gotterbarm Tobias , Klotz Matthias 
Published: December 2019

Abstract
Background Surgical hip joint reconstruction is the method of choice for children and adolescents with developmental dysplasia of the hip (DDH). After surgery, immobilization using a spica cast is considered to be the gold standard for preventing redislocation of the hip, dehiscence of the tightened hip joint capsule or secondary dislocation of the osteotomy. Neverthess, spica cast treatment may cause complications like hygiene problems, skin lesions, neurological deficits and rigidity of the adjacent joints. An alternative for postoperative immobilization is a foam splint. The purpose of this randomized controlled trial is to compare spica cast and foam splint immobilization after hip reconstruction in children and adolescents with DDH. The hypothesis of this study is, that foam splint immobilization leads to a higher satisfaction during postoperative aftercare in the patients and their caretakers. A further intent of the study is to analyse the complications occurring under the immobilization. Methods In a prospective randomized clinical trial children and adolescents (age: 4-14 years), who were diagnosed with DDH and received hip reconstruction surgery were included. Patient recruitment, group allocation, surgery and aftercare will be carried out at the Department for Department for Orthopedics and Traumatology, Kepler University Hospital, Linz, Austria. The approval of this study was granted by the local ethics committee (EK1183/2018) and a written informed consent will be obtained from each patient or his legal representative before start of the study. The study is funded by the Medical Society of Upper Austria and registered in the German Clinical Trials Register (DRKS-ID: DRKS00016861). A standardized questionnaire (SF-36, EQ-5D, CPCHILD) as well as a radiological assessment is gathered before, six and twelve weeks after surgery. Statistical methods are epidemiological calculations, analysis of covariance, t-test, chi-square test and graphical methods for visualisation. Power analysis showed a minimum optimum sample size of 15 individuals per group (t-test, two-sided, Cohen d 1.1, alpha=0.05, 1-beta=0.80). Discussion Recent retrospective studies suggest that foam splint immobilization after hip reconstruction surgery is a safe and feasible method, promising fewe complications rates compared to spica casting. Nevertheless, no prospective randomized clinical trials have been published to prove the promised and suspected benefits of foam splints compared to spica cast immobilization. Clinical trials on children, especially with physical and mental disorders, need to be planned with rigorous care for general ethics and legal rights. Advice from ethical review committees, self-help groups and legal advisers is mandatory. The presented clinical trial was planned under such strict standards and meets ethical and legal criteria. The results of this clinical trial will be published in national and international meetings for pediatric orthopaedics as well as in international journals for pediatric orthopaedics. The aim is to provide profound criteria for the usage of a foam splint instead of casting in immobilization after hip reconstructive surgery. Benefits for the patients may be fewer complications and no need for a second anaesthesia for recasting. Up to now, a comparable study does not exist.