Hinged Versus Conventional 8 Plate for Correction of Genu Valgum or Varum

Study Overview
=================
Brief Summary
-----------------
To assess the therapeutic effect of hinged 8-figure plate by comparing with the traditional 8-figure plate through a randomized controlled clinical trial by assessing the differences between preoperative and postoperative data. The hypothesis is that the hinged 8 plate provides low complications that this treatment is as good as the traditional one.

Detailed Description
-----------------
Angular deformities of the lower limb is major clinical problems encountered in pediatric orthopedics. Deformities can be either valgus or varus and most commonly affect the knee joint, which may result in patella dislocation, gait instability and serious impact on the appearance and function of the lower limbs. Biomechanical studies and gait analysis found that genu varus increased medial articular surface pressure of the knee, while genu valgus increased lateral articular surface pressure, and both of them are the risk factors for osteoarthritis. Surgical treatment techniques include osteotomy and hemiepipysidesis. Osteotomy surgery is the gold standard for severe angular deformity or epiphyseal closed patients, but it was associated with lots of complications, including osteofascial compartment syndrome, neurovascular injury, deep soft tissue infection, nonunion and requiring a long recovery time. While, for patients whose epiphyseal is not closed, the traditional 8 plate hemiepipysidesis has fewer complications. However, it showed some problems in clinical applications, such as steel plate or screw broken. The investigators designed a new hinged 8 plate, which has two arms and a built-in hinge. Based on the previous studies, investigators designed the rotation of the two arms ranged from 155° to 170° to better fit the contour of the physis in all stages of angular correction. That automatic change can also disperse repeated stress on the surface of periosteum and perichondrium during walking. The plate had been tested on animal models that the use of the hinged plate and screw system may be a more reliable technique with minimal complications for correction of angular deformities of the lower limb.

Official Title
-----------------
Comparison of the Outcomes of the Treatment of Semiepiphysiodesis Using Hinged and Conventional 8-figure Plates: A Randomized Controlled Clinical Trial

Conditions
-----------------
Genu Valgum or Varum, Growth; Arrested, Bone, Epiphyseal Arrest, Lower Leg

Intervention / Treatment
-----------------
* Device: hinged 8-figure plate
* Device: conventional 8-figure plate


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Idiopathic genu valgus or varum Without any treatment lower limb mechanical axis over the tibial plateau in the range of 1/2; Epiphyseal not yet closed, with more than 12 months of growth potential Exclusion Criteria: Physiological genu valgus or varum Epiphyseal have closed or no growth potential Pathological limb deformity(Blount disease, inflammation,trauma) Other causes of lower limb angular deformity. With surgical contraindications

Ages Eligible for Study
-----------------
Minimum Age: 2 Years
Maximum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Hinged 8-figure plate<br>Hinged 8-figure plate is a novel devise that has modifications in order to improve the treatment effect of conventional 8-figure plate. This arm will be used to verify the effectiveness and feasibility of the modification. | Device: hinged 8-figure plate<br>* Hinged 8-figure plate has two arms and a built-in hinge. The rotation of the two arms ranged from 155° to 170° to better fit the contour of the physis in all stages of angular correction. That automatic change can also disperse repeated stress on the surface of periosteum and perichondrium during walking.<br>|
| Active Comparator: conventional 8-figure plate<br>Conventional 8-figure plate is widespread method to treat genu varum and valgus. This arm, as a comparator, will be the control group to verify the feasibility of the novel hinged 8-figure plate. | Device: conventional 8-figure plate<br>* Conventional 8-figure plate is a widespread device to treat angular deformity of lower limbs with moderate successful rate. The device was designed based on the principle of tension band model. It consists of a plate and two screws (epiphyseal screw and metaphyseal screw).<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The complications. | Surgery related complications including osteofascial compartment syndrome, neurovascular injury, deep soft tissue infection and so on will be observed until correction of deformity. | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The corrective rates of medial slope angle. | The angle of medial slope will be measured when reexamination until the correction of deformity, which was used to calculate the corrective rates. | 2 years | 
| The corrective of Mechanical lateral distal femoral angle. | The corrective of Mechanical lateral distal femoral angle will be measured when reexamination until the correction of deformity. And investigators will calculating the change of this angle. | 2 years | 
| The movement of two arms of the hinged plate. | The movement of two arms during the experiment will be noted by the changing of two arms angle when reexamination until the correction of deformity. | 2 years | 
| The residual stress on the implants. | Residual stress (remaining stress of the sample after implant removal) at the rim of the metaphyseal screw hole will be measured using X-ray diffraction. | 2 years | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
genu valgum or varum, eight-plate, epiphysis arrest, hemiepiphysiodesis