A Randomized Controlled Trial of Leg Length Discrepancy Techniques

Hospital for Special Surgery (HSS)

Status: Terminated

Conditions: Leg Length Discrepancy

Treatments: Procedure: Percutaneous Drill Epiphysiodesis; Device: Tantalum Beads & Injector; Procedure: Percutaneous Screw Epiphysiodesis

Study type: Interventional

Funder types: Other

Identifiers

NCT02260856

2014-174

Details and patient eligibility

About

This is a randomized clinical trial of epiphysiodesis techniques: percutaneous transphyseal screw epiphysiodesis versus percutaneous drill epiphysiodesis for the correction of leg length discrepancy. Failed epiphysiodesis was selected as the primary outcome. Failed epiphysiodesis was defined as one or more of the following: development of angular deformity > 5°, revision epiphysiodesis, or growth inhibition < 70% of expected. EOS, low dose biplanar X-Ray, will be used to make all length measurements. Secondary outcomes assess mean growth at the physis following epiphysiodesis, in the subset of patients with bead implantation, fluoroscopy and operative times, length of stay, return to full weight bearing, as well as functional and quality of life outcomes. The following outcome scales will be used to measure pain (VAS), quality of life (PROMIS Pediatric Pain Interference Scale), and function (PROMIS Pediatric Mobility Scale, Pedi-FABS, and UCLA Activity Score). Each of these scales has been validated for use in children (Beyer, Denyes, & Villarruel, 1992; DeWitt et al., 2011; Fabricant et al., 2013; Novais et al., 2014; Varni et al., 2010a). We will also determine the cost associated with each technique and perform a cost-effectiveness analysis to establish which technique is preferred from a societal perspective.

Full description

Drill and screw epiphysiodesis are the two most common techniques for surgical correction of predicted limb length discrepancies 2-5cm. Both procedures require minimal incisions, less than 1cm, (Canale & Christian, 1990; Metaizeau et al., 1998). Previous studies have demonstrated that both drill and screw epiphysiodesis result in improved outcomes compared to open techniques (Alzahrani, Behairy, Alhossan, Arab, & Alammari, 2003; Canale & Christian, 1990). Moreover, alternative approaches such as medial and lateral 8 plates may not sufficiently tether growth, or cause peripheral but not central growth arrest (Stewart et al., 2013). We selected drill vs. screw epiphysiodesis as the two treatment groups as they are both minimally invasive, relatively effective, in common usage, and are thought to differ in costs and other characteristics.

Although outcomes of drill and screw epiphysiodesis exist{{10 Campens,C. 2010; 11 Ghanem,I. 2011}} , the assessments are retrospective non-randomized series, which may be at risk for selection bias, and may not adequately capture all of the outcomes of interest, depending on what data is routinely collected and documented in the medical chart. To our knowledge, no prospective randomized comparison of epiphysiodesis techniques and clinical outcomes has been published accurately assessing how effective each technique is in disabling growth at the physis, or taking into account patient-centered outcomes or cost. Operative measures such as the surgical time and radiation exposure from intra-operative fluoroscopy have not previously been compared. Patient-centered outcomes such as level of pain, activity, and function by measures such PROMIS and Ped-FABS, have not been previously assessed in this population. The proposed research study aims to fill this gap.

This study was designed as a multicenter randomized trial to answer an important clinical question and to do so with a clearly defined objective and validated outcomes. This trial can be executed on a relatively small budget with simple outcome measures, and recruitment of a moderate number of patients at each of a few centers well equipped for research. By involving multiple surgeons and patients from various geographies, we improve the generalizability of this study. Our institution and collaborating institutions have been successful in completing randomized clinical trials in the past. This study will answer a clinical question that is important and current, providing orthopedic surgeons with an evidence-based identification of the ideal technique for treating predicted limb length discrepancies 2-7cm.

This study will also be the first to accurately measure mean growth following both epiphysiodesis techniques, through implantation of tantalum beads in consenting participants. These beads will provide stationary landmarks by which growth can be measured directly, and not inferred. Previous methods of judging epiphysiodesis success have primarily relied on assessing efficacy by estimating growth inhibition through calculation. Tantalum beads have been successfully used in adults and children (Lauge-Pedersen,H. 2006), and although it requires implantation of small radio-opaque beads, it is considered the gold standard when making detailed radiographic measures, and the optimal technique for physeal growth measurements.(Lauge-Pedersen,H. 2006)(Haugan,K. 2012). Over 300 000 beads have been inserted in vivo without significant complications.

Enrollment: 170 estimated patients

Sex: All

Ages: 7 to 18 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Open growth plates
• Skeletally immature requiring isolated complete epiphysiodesis of the distal femur and/or proximal tibia
• At least one year of predicted growth remaining
• Less than 18 years of age
• Predicted limb length discrepancy 2-7 cm

Exclusion criteria

• Patients undergoing additional orthopedic procedures at time of epiphysiodesis
• Metabolic bone disease or "sick physis" syndrome, that may cause bone to grow in an unpredictable manner.
• Pregnancy

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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170 participants in 2 patient groups

Percutaneous Drill Epiphysiodesis

Active Comparator group

Description:

A 5 mm incision will be made centered over the physis both medially and laterally. A 4.5 mm drill will be passed repeatedly across the physis in a divergent manner. Curettes will then be used to further remove and disrupt the growth plate. Fluoroscopy will be used throughout to ensure proper passage of the drill and curettes. Omnipaque dye will then be inserted to confirm ablation of the physis.

Treatment:

Procedure: Percutaneous Drill Epiphysiodesis

Device: Tantalum Beads & Injector

Percutaneous Screw Epiphysiodesis

Experimental group

Description:

In the distal femur, guide wires will be placed in an antegrade fashion, with an 8 mm skin incision proximal to the physis both medially and laterally. The guide wire will be placed with the medial wire crossing the physis at the junction of the middle and medial third of the physis. The lateral guide wire will cross the physis at the junction of the lateral and middle third of the physis. The wires will extend into the epiphysis, but will not enter the joint. The guide wires will be over drilled with a 5 mm drill, and 7.3 mm fully threaded cannulated screws will be placed across the growth plate. For tibias, screw placement will be retrograde, with 8 mm incisions made medially and laterally distal to the physis, with guide wires aiming proximally.

Treatment:

Procedure: Percutaneous Screw Epiphysiodesis

Device: Tantalum Beads & Injector