Fitbone

A telescoping nail sits in the marrow canal, locked with screws above and below the cut. A small receiver is placed under the skin at the end of the nail, near the knee for a femoral nail, and joined to it by a thin cable. Outside the body, the Fitbone Control Set, electronics plus a transmitter on a lead, sends energy through the skin to the receiver, which powers the motor in the nail. The Orthofix guide: "There is no contact between the implanted intramedullary lengthening nail and the surface of the body." No magnets are involved, the design difference from PRECICE.

Distraction begins around the fifth day after surgery, at a rate "starting from 1 mm/day" that the surgeon adjusts to the X-rays. In a 34-patient French series the daily millimetre was split into three sessions. You hold the transmitter over the receiver, run the session, and write it in the distraction log the guide asks every patient to keep; that log is how a malfunction or a missed day gets caught. The patient's set only lengthens; shortening needs a clinician-only retraction set, and the implant "is not suitable for applying compression forces".

Orthofix's guide lists the indication as limb lengthening of the femur and tibia in adults and in pediatric patients older than 12 through 21. Its contraindications are specific about weight: more than 100 kg for the TAA11 and TAA13 nails, more than 50 kg for the slimmer TAA09. It also excludes leg-length differences under 20 mm, open growth plates the nail would cross, poor bone quality, a canal too narrow for the nail, bone infection that cannot be reliably excluded, metal allergy, pregnancy, and "expected non-compliance".

That 20 mm line is written for discrepancy cases. A cosmetic patient has no discrepancy, so ask the surgeon how the indication is documented. Two points follow from the electronics. The implant is MR unsafe; the guide says to keep away from MRI rooms. And electrical therapy through the limb, therapeutic ultrasound and magnetic-field therapy are to be avoided while the nail is in, with extra monitoring for a few days if a defibrillator has to be used. Raise any of those before choosing this nail.

The nail comes in three sizes, TAA09, TAA11 and TAA13, for which the guide has the canal reamed to 9, 11 or 13 mm, each in several stroke lengths; the stroke caps the gain from one surgery, so ask which is planned. In the 128-nail French series, lengthening ranged from 1.5 to 8 cm, mean 4.7 cm. Distraction runs from 1 mm a day, adjusted to the regenerate; the guide warns not to pause more than two days or the gap can bridge early. Load is the strict part: during distraction the implant must not carry more than 20 kg, "flat foot contact", walking aids are mandatory, and more than that can break the nail. Weight-bearing rises during consolidation as the X-rays allow.

Fitbone is "not a permanent implant and must be removed". Orthofix recommends removal once the regenerate carries load, "in general a period of 1 to 1 ½ years after implantation", and warns the nail may break if removal is delayed or skipped. Removal takes out nail, cable and receiver through the old scars. In the 34-patient series the mean interval to removal was 19.7 months, so plan for a second operation over a year out.

The guide's own side-effect list runs from "slight tingling to severe pain" during and after distraction and temporary loss of joint motion, plus the two mechanical warnings above. There is also more hardware than in a magnet nail: a receiver pocket and a cable that must survive the treatment and then be removed. The largest multicentre dataset is the 2023 Acta Orthopaedica cohort of 314 nails, 234 of them Fitbone: 53% of patients had at least one complication, device-related problems were the most frequent cause, and none of those left permanent harm. In crude figures Fitbone showed more complications per nail than PRECICE, but the difference disappeared in the adjusted analysis.

One risk it does not appear to share is the Stryde junction problem. A 2023 study of 128 Fitbone nails followed for a mean of 925 days found no focal osteolysis or periosteal reaction at the telescoping junction in any bone. What it did find was cortical thickening around the locking screws in 79% of nails, more than previously reported, and the authors called the absence of osteolytic change reassuring.

Fitbone sits in the same premium band as PRECICE 2: an internal, single-use implant for each bone, delivered as a per-patient system of nail, receiver and control set, with a removal operation at the end. It is most often quoted from centres in Germany, where it was developed with Prof. Rainer Baumgart, and from Turkey; Orthofix said at the 2020 acquisition that it had been used in more than 3,500 cases across more than 15 countries. What moves the number is the country's hospital overhead, the surgeon's fee, and how much of the 1 to 1 ½ year course the package covers.

Ask about physiotherapy, because the guide assumes regular prescribed physio and walking aids for months, and about the removal surgery, a separate admission. A package that ends at discharge from the lengthening admission is pricing the first part of the treatment only.

Questions to ask. Which nail, TAA09, TAA11 or TAA13, and does my weight sit under the limit for it? What is your weight-bearing rule during distraction, and does it match the manufacturer's 20 kg? When do you remove the nail, who does it, and is it in the quote? Who trains me on the control set and checks my distraction log? What is your plan if I over-distract or the motor stops? How do you document a cosmetic indication given the guide's discrepancy wording?

Red flags: marketing Fitbone as a "weight-bearing nail" or promising early full weight-bearing, which the guide contradicts; any suggestion the nail can stay in indefinitely; no mention of the receiver, the cable or the second scar; no distraction log; and a promise that MRI will be fine. A clinic that hands you the control-set instructions and the log before surgery is behaving the way the manufacturer expects.