Foam splint versus spica cast - Early mobilization after hip reconstructive surgery in children - A prospective randomized clinical trial

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.

4 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.

Background
Developmental dysplasia of the hip joint (DDH) and deformations of the proximal femur may be congenital. In addition to that many patients with neuromuscular disorders like cerebral palsy (CP) or myelomeningocele (MMC) have neuromuscular dysplasia of the hip (NDH) and/or dislocation of the hip.(1) Results may be pain when walking/standing/sitting as well as problems with walking or even the disability to stand.
In early childhood DDH or dislocation of the hip may be treated by casting or splinting. In case of failed conservative treatment surgical reposition and reconstruction of the hip is needed. Children with neuromuscular disorders show a high incidence of hip dislocations and failed conservative treatment due to NDH and DDH. (2) In CP, different authors could show an incidence of hip dislocation in 18-60% of their patients.(3) Especially in older children, who are already able to walk, tight soft tissue makes the procedure challenging. In most cases, a combination of soft tissue and bony procedures is necessary to achieve a reduction of the joint. (4,5) After surgery immobilization usually is done by spica-casting for six weeks, In a prospective randomized clinical trial we now want to show, that the foam splint leads to a higher satisfaction with the postoperative situation in the patients and their caretakers. Furthermore we want to show a lower number of complications, than in our control-group. Benefits for the patients may be fewer complications, a higher quality of life during the aftercare process and no need for a second anaesthesia for recasting. Up to now, a comparable study does not exist to our knowledge.

Methods/Design
We designed a non blinded, prospective randomized clinical trial to prove our Assignment process is random, using a coin-toss.
Criteria for exclusion are a lack of consent and cooperation.
Criteria for termination of the study is discontinuation of usage of foam splinting due to adverse events.
Individual criteria for termination of the study are loosening of osseous correction and withdrawal of informed consent.
Data storage and analysis is done pseudonymised. No data will be given to external partners, therefor no additional data monitoring committee is needed. No auditing is planned.
8 Statistical methods include a detailed epidemiological description with mean standard-deviation, minimum, maximum, median at continuous data and scores, relative frequency for explained variables. The main target, the CPCHILD-score, is analyzed using analysis of covariance using the assigned group as factor and the baseline score as discrete variate. All other characteristics are analyzed with a ttest or chi-square-test. When appropriate, graphical methods for visualisation are used.
The algorithm of the recruitment process is shown in figure 6. Complications are counted and cost-effectiveness is calculated.

Patient and Public involvement
The planning study was supported by the local ethical review committee including the representative for disabled patients, which provides professional ethical and legal advice. The ethical review committee reviewed the study protocol during the planning of the clinical trial and gave advice on ethical and legal topics. The committee partnered with us for the design of the study, the informational material to support the intervention, and the burden of the intervention from the patient's perspective.
Pseudonymisation of obtained data is performed. Data will be published after data collection in oral and written communication. Patients are informed of the results during their routine check-ups.

Discussion
Minors are not legally able to give informed consent and need their legal guardian's consent. The decision to participate in a clinical trial needs to be made carefully, with in depth discussion with the legal guardian, and appropriate discussion with the child, depending on their age and capacity. Dysplasia of the hip needs to be treated before the child is old enough to give informed consent, to prevent  completed_SPIRIT_checklist.docx