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Indications for Use
The Biomet
®
OrthoPak
®
Non-invasive Bone Growth Stimulator System is indicated for the
treatment of an established nonunion acquired secondary to trauma, excluding vertebrae and all
flat bones, where the width of the nonunion defect is less than one-half the width of the bone to
be treated. A nonunion is considered to be established when the fracture site shows no visible
progressive signs of healing. The original approval was based on a PMA Study, which included
69 patients with efficacy of 72.5%. An additional cohort of 21 recalcitrant patients with multiple
prior procedures and unsuccessful electrical stimulation with different modality was added and
yielded efficacy of 33.3%. Seventy-nine patients out of 90 treated had at least 4 years follow-up
after the date of treatment termination for a follow-up rate of 88%. The follow-up results were 45
patients healed; four previously healed patients have died; three patients, who were “healing” at
the end of treatment, were healed with additional treatment. Counting only the 45 unconditionally
healed patients, the efficacy at 4 year follow-up was 50%. A subsequent survey of 295 patients
conducted from March 1988 to September 1990 by an independent agency, yielded an efficacy
of 73.2%.
Device Design Rationale
The Biomet
®
OrthoPak
®
Non-invasive Bone Growth Stimulator System provides a noninvasive,
transdermally applied electrical treatment of nonunions acquired secondary to trauma.
The transdermal application of the treatment current to the patient has been also referred to
as “capacitive coupling”, to denote the resulting capacitive phase shift between the treatment
current and the applied voltage in the Biomet
®
OrthoPak
®
Non-invasive Bone Growth Stimulator
System. The time varying electrical field developed in the tissue between the electrodes is
distributed through a wide volume of tissues, including bone. Thus, some latitude is permitted
in the placement of the electrodes. A 20 degree misalignment is allowed in the placement of the
electrodes on either side of the nonunion site, and the permissible tolerance in the plane of the
long axis of the bone is equal to the diameter of an electrode (i.e., plus or minus 1-3/8 inches).
Utilization of this device allows full weight bearing on the casted extremity unless gross motion
(greater then 5 degrees in any plane) at the nonunion site is presented. In such cases, weight
bearing is not advised.
Contraindications
The use of this device is contraindicated if the individual has synovial pseudoarthrosis.
Warnings
Utilization of this device allows full weight bearing on the casted extremity unless gross motion
(greater than 5 degrees in any plane) at the nonunion site is present. In such case, weight
bearing is not advised and should not be permitted as this may compromise the effectiveness
of the treatment. The safety and effectiveness of the use of the device on individuals lacking
skeletal maturity has not been established. In the presence of a maligned nonunion, careful
consideration on the use of this device must be undertaken on an individual basis, as treatment
with this device is not yet intended to alter or affect the degree of malalignment.
Animal safety studies conducted to date indicate that the Biomet
®
OrthoPak
®
Non-invasive
Bone Growth Stimulator System does not interfere with the normal intrinsic activity of
the heart. However, the Stimulator does interfere with the operation of certain pacemakers.
The concomitant use of the device and a pacemaker must be assessed on an individual basis,
prior to use (such as with an electrocardiogram). The amplitude of the treatment current must
be between 5 and 10 milliamperes RMS.
Treatment with this device is not recommended on patients whose electrical impedance of
the tissue between the electrodes will not allow the device to operate within the prescribed 5
to 10 milliamperes range. The safety and effectiveness of the use of this device on individuals
with nonunion secondary to, or in conjunction with, a pathological condition has not been
established.
Animal studies conducted to date do not suggest any long term adverse effects from use of this
device. However, long term effects in humans are unknown. General tissue sensitivity at the skin/
electrode site with unknown specific etiology may occur. This tissue sensitivity may be caused by
the electrode gel, excess perspiration or a combination of both. Such a reaction generally resolves
spontaneously following diagnosis and correction of the underlying cause.
Other components, accessories and parts may not be compatible, and may damage the device.
If any component does not function properly, contact Biomet. No attempt should be made to
modify or repair the device.
Precautions
Although laboratory teratological studies performed with this device demonstrate no adverse
findings, the safety of this device used during pregnancy and nursing in humans has not been
established.
Compliance with the treatment schedule, daily battery pack change and proper maintenance
of the device and the change of the electrodes are essential. The device will not perform
properly and treatment may be unnecessarily prolonged if you fail to adhere to the care routine.
Components in this system are to be used only with Biomet approved parts. No attempt should
be made to modify or repair this device.
