UniX® Metaphyseal Hinge Fixator

The UniX® Metaphyseal Hinge Fixator is a unilateral external fixator for gradual or acute correction of frontal-plane deformities of the proximal tibia, with a hinge that aligns to the center of the deformity and corrects up to 20° of varus or 10° of valgus.

Available in three sizes (small, medium, large) to match tibial anatomy, fixed with four conical 6 mm titanium half pins.

At 9 mm thick, it is one of the lowest-profile external fixators available, supporting patient comfort through the correction and consolidation period.

All-titanium construction keeps the frame lightweight and easier to maintain than a ring fixator, positioned over the region of thinnest soft tissue coverage at the knee.

Designed on the idea and patent of Prof. Rainer Baumgart MD, trauma surgeon and mechanical engineer.

Acute correction with a static plate does not account for how the surrounding ligaments react once the patient bears full load, which can leave the construct under- or over-corrected relative to the plan. Correcting from valgus to varus acutely can also stretch the peroneal nerve, risking drop foot.

Gradual correction with the hinge lets the surgeon adjust the angle under load, reducing the risk of over- or under-correction and nerve traction injury.

New bone forms by callus distraction, the same mechanism used in limb lengthening, rather than requiring a fixed osteotomy reduction at the time of surgery.

For open-wedge corrections, gradual distraction can avoid the need for iliac crest bone grafting.

UniPlasty® is Response Ortho's joint-preserving realignment technique built around the UniX Metaphyseal Hinge Fixator, built around four priorities for the surgeon and patient:

Minimally invasive — correction is achieved through small incisions rather than an open reduction.

No major secondary surgery for removal — the frame and pins come out in a smaller outpatient procedure once healing is confirmed.

No residual material in the body — no permanent plate or screws remain in the bone once the frame is removed.

Accurate alignment — the adjustable hinge lets the surgeon fine-tune the correction under load, rather than committing to a single acute reduction.

After a post-operative waiting period of 5–7 days, the hinge is adjusted twice daily — 0.33° each time, for a combined 0.66° per day — until the planned correction is reached. Bone consolidation typically takes 2–3 months, bringing the frame's total time on the leg to approximately 3–4 months before removal, once radiographs confirm sufficient healing.

Surgical technique details, dosing schedules and case material are available at www.UniPlasty.com.

This product is CE-marked and has also been cleared by the FDA for distribution in the United States.