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Orthofix Eight-Plate Has Unacceptable Failure Rate in Blount Disease

Blount disease, a disorder that affects the growth of the tibia (shin bone), can make children with the disease look like they have a bowleg.
To correct this, surgeons work on fixing the tibia to straighten it, choosing one of several available techniques. One such technique is called the Orthofix eight-Plate, which is a tension band device designed to repair and straighten the bone, and strengthen it.

The authors of this article studied 24 patients (total of 31 deformities) to see how effective the Orthofix eight-Plate treatment was. Sixteen of the patients (18 legs total) had Blount disease and the other patients had deformities due to other reasons. All the patients had plates put on the tibia (shin bone) and 10 also received plates on the femur (thigh bone). The usual follow-up was about 17 months for the patients, with the shortest period being a year.

The results of the review found that the implant failed 26 percent of the time (in 8 cases) and all eight were among the patients who had Blount disease. The part that was broken in each case was a screw in the tibia and it usually happened around 13.6 months after surgery. No failures were found with the rest of the patients, those who didn't have Blount's disease.

To investigate possible causes, the researchers looked at the children's weights. The mean weight of the children whose repair failed was 95.3 kilograms (210 lbs) and the non-failure group mean weight was 76.8 kg or 169 lbs. The children with Blount disease, whether in the failure group or not, was 93.2 kg or 200 lbs, compared with 65.4 kg, or 144 lbs, in the children who didn't have Blount disease. However, within the group with Blount disease, the weight of a child didn't seem to have any connection to whether the procedure was a failure.

The authors concluded that while the Orthofix eight-Plate procedure was acceptable for correction of the deformities in children who didn't have Blount disease, the failure rate among Blount disease children was unacceptable.

References: Samuel Schroerlucke, MD, et al. Failure of Orthofix eight-Plate for the Treatment of Blount Disease. In Journal of Pediatric Orthopaedics. January/February 2009. Vol. 29, No. 1. Pp. 57 to 60.

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