eight-Plate from Orthofix

Genu Varum - Dysplasia

C.W. is a three-year-old boy who developed progressive bow leg deformities causing leg pain, difficulty running, and a waddling, awkward gait. He has a hereditary bone growth abnormality (skeletal dysplasia) contributing to his deformity. It is likely that this eccentric loading is the cause of the patient's discomfort. The waddling gait results from the bow at the top of the femur (coxa vara).

Metaphyseal Dysplasia

The mechanical axis (or center of gravity) is represented by a dotted line drawn from the center of the hip to the center of the ankle. Normally this should bisect the knee (solid white line). The greater the distance between the actual vs. desired axis, the more outward force is subjected to the knee. The forces of gravity and weight-bearing combine to perpetuate the bowed deformity while subjecting the knee ligaments and cartilage to pathological overload.



Using the guided growth technique with the eight-Plate, the bones were never cut, neurovascular risk was avoided, instability was avoided, and there was no healing interval. Correction occured gradually through growth. As growth occured, the screws were free to diverge but the plate resisted longitudinal expansion on the instrumented side of the growth plate.



One year following surgery the center of gravity (depicted by the dotted white line) has been restored to the center of the knee. The plates were then removed. The child's symptoms have completely resolved; he is able to run and pursue full activities ("function follows form"). As long as the periosteum is left undisturbed, there will be no permanent or irreversible effects upon the growth plate.

By centralizing the forces of gravity and weight-bearing the knee ligaments, cartilage, and physis are spared deleterious shear and overload. Subsequent to eight-Plate removal, further growth should be monitored. If there is recurrent deformity, guided growth may be safely repeated.

Through understanding and patience, even complex deformities may be gradually and safely corrected through redirecting the physis without the risks and problems associated with the traditional methods requiring osteotomy and immobilization. This minimally invasive and biologically sound technique represents a powerful new tool in the orthopedic armamentarium.

Guided growth is applicable to virtually any angular deformity of any etiology, in any size child, providing the physis has not closed. Patient and parent acceptance is uniformly enthusiastic compared to other available techniques.