Pediatric 8 Plate

Children need gentle guidance and correction in many aspects of their lives. For a significant number of children who do not spontaneously grow out of "bowed legs" or knock knees", pain and/or difficulty in running may ensue. These children can benefit from a new, minimally invasive surgical procedure that involves the insertion of a small device called the eight-Plate.™ The eight-Plate gently guides growth while allowing natural, safe and gradual correction of limb alignment. Growing up is tough enough on both children and their parents! Using the eight-Plate, your surgeon can accurately and selectively correct limb deformities so that your child can get on with growing up -strong and straight. Read on for more information about the correction of limb deformities using the eight-Plate and a procedure referred to as Guided Growth.

Knock Knees and Bowed Legs
In normal skeletal growth, limbs are equal in length and are properly aligned from the hips to the ankles. Sometimes, however, congenital abnormalities, infection, injury or other conditions can cause long bones of the leg (e.g., tibia, femur) to grow out of alignment.

This misalignment often may result in joint deformities of the leg known as valgus (knock knees) or varus (bowed legs) deformities. In these situations, normal use of the leg is impaired and walking or running may be painful. Unfortunately, bracing is not effective in the management of these conditions. The correction of limb deformities requires one of two surgical procedures: either an osteotomy [os-te-ot´o-me] or the minimally invasive hemi-epiphysiodesis[hemi-ep-i´fiz-e-o-de´sis] procedure.

Corrective Surgical Procedure
Correction using the osteotomy method is a significant surgical procedure that involves cutting the misaligned bone, adding or removing a wedge of bone (depending on the type of deformity) and realigning the bone. The realigned bone must be fixed into place with pins or with a plate and screw combination followed by a cast. Another alternative is to fix the realigned bone in place using pins in the bone segments and connecting them to an external frame. In addition to the inherent risks of such a surgery,the child must endure a prolonged hospital stay and delayed weight bearing,followed by a course of physical therapy. In many cases, multiple osteotomy surgeries may be necessary to fully correct the leg's alignment.

In contrast, correction using hemi-epiphysiodesis is a much less invasive surgical method for correcting pathological angular deformities. Epiphysiodesis is a term from the Greek in which "physis" means growth plate and "desis" means tether. This procedure, traditionally known as "epiphyseal stapling" utilizes surgical staples (typically 2 or 3) on one side of the physis, restricting its growth while permitting continued growth on the opposite, non-instrumented side. The goal is to permit realignment through growth. More simply put, bone growth is restricted on one side of the deformity while bone growth continues on the other side. Gradually, the bone realigns and the deformity is corrected. Since the bone is not cut (as with an osteotomy),there is no neurovascular risk, instability from the cut, or significant period of healing.

Despite the fact that epiphyseal stapling has been used with success for more than 50 years, there are drawbacks and limitations to the use of staples. Staples are rigid, U-shaped implants that allow no flexibility during the growth and realignment of the bone. Additionally, the staples compress the growth plate on one side. Surgical planning for the precise placement of the staples is complicated. Furthermore, when rigid implants such as staples are confronted by the powerful forces generated by physis (growth), the staples may migrate, bend or break and compromise the outcome. Staple retrieval or revision may prove difficult, resulting in inadequate correction (or over correction) of the deformity.

Correction Through Guided Growth Using the Orthofix eight-Plate
The new eight-Plate technique of Guided Growth overcomes the drawbacks associated with traditional hemi-epiphyseal stapling and can give your child improved correction of their pathological angular deformity.

The Orthofix eight-Plate or 'Guided Growth Plate' is a unique, figure-eight shaped device about the size of a paper clip that allows gradual correction of your child's limb deformity. The eight-Plate holds one side of the growth plate. As the opposite side of the physis continues to expand and grow, the screws diverge within the plate, effectively serving as a hinge. This hinge action also avoids compressing the growth plate that is being guided. And because of its flexibility, the chances of the plate or screws bending or breaking under the forces of bone growth are virtually eliminated.

The Surgical Procedure
Surgical implantation of the eight-Plate is performed under anesthesia and takes about an hour. During the procedure, the surgeon will make a 2-3 cm(approximately 1") incision at the physis of the bone to be corrected. The eight-Plate is secured to the bone with two small titanium screws. For "knock knees" the eight-Plate is placed on the medial side of the bone (i.e., inner side);for bowed legs, the eight-Plate is placed on the lateral side of the bone (i.e., outer side). Multiple deformities can be addressed during the same procedure, inserting one eight-Plate per physis. The incision is closed, generally with resorbable sutures. After recovery from anesthesia, your child may be taken home.

Post-Operative Recovery
The eight-Plate technique of Guided Growth involves minimal surgical trauma and pain when compared to an osteotomy. There is no cast; crutches are optional (for comfort) and physical therapy is seldom required. Your child is encouraged to walk and resume activities as tolerated, including sports when comfort permits, which is typically within 3 weeks.

Correction Occurs Gently Over Time
The eight-Plate temporarily restrains growth on one side of the bone plate while natural growth is allowed to continue on the opposite side. Gradually over time, (typically from several months up to one year) the deformity is corrected. To ensure timely and adequate correction, your child needs to be seen by the surgeon every 3 months for a check-up. If your child cannot return to the surgeon every 3 months, due to distance for example, another doctor should take x-rays of the legs (the most accurate film is a full length view taken in the standing position). Send these x-rays to the surgeon who implanted the eight-Plate. When the deformity is corrected, the surgeon will remove the eight-Plate, under anesthesia, in an out-patient surgery.

Glossary

Diaphysis - the middle shaft of a long bone, between the growing regions near the ends.

Epiphysis - the end of a long bone that makes up a joint, and that hardens and attaches to the shaft of the bone with age.

Epiphysiodesis - an operation to stop the activity of a growth plate. The effects can be permanent or temporary

Femur – the long bone of the thigh

Fibula - thin lower leg bone

Hemi-epiphysiodesis - to tether or restrain one side (medial or lateral) of the growth plate with an implant, such as a staple.

Implant – device inserted into a tissue for a specified period of time which is not absorbed by the body

Lateral – outer side, away from the middle or median plane

Physis - growth plate near either end of the long bones (femur and tibia) which allow for elongation. These close naturally at maturity (girls at age14, boys at age 16 approximately)

Medial – inner side near the midline

Metaphysis - the body of cartilage that separates the epiphyses (end) and the diaphysis (shaft) of long bones during growth. It is this part of the bone that grows during childhood; at roughly 18 to 25 years of age, it changes from cartilage into solid bone.

Osteogenesis – the step by step process of natural bone growth

Osteotomy – cutting a bone into two segments

Tibia – the larger leg bone between the knee and ankle (shin)

Varus - in outward angulation of the knee in which the knees are separated while the ankles are touching; "bowed legs"

Valgus - an inward angulation of the knee in which the ankles are separated while the knees are touching; "knock knees"