Fitbone
Advanced intramedullary lengthening system
The Fitbone™ system is an advanced intramedullary limb lengthening technology developed in Germany. Unlike older methods, Fitbone uses a fully internal motorized nail that is controlled externally. This design eliminates pin-site infections, minimizes scarring, and makes the lengthening process more comfortable.
Fitbone is especially valued by patients who want both medical safety and a more natural daily life during treatment. With Fitbone, you can walk with support right after surgery, perform daily lengthening sessions yourself, and stay mobile without external frames or long-term wheelchair use.
How Does the Fitbone Method Work?
The Fitbone method works through a simple but highly precise process. Everything happens inside the body with no external frames, and patients control the daily lengthening with a small handheld device. While you focus on your goal, the surgeon guides the pace and monitors progress with regular follow-ups and X-rays. Here’s how it works in practice:
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Surgery and hospital stay: The Fitbone nail is implanted inside the bone under general anesthesia. A small receiver is placed under the skin and connected to the nail. The operation takes 1.5 to 2 hours. Patients usually stay in the hospital for 5 days. Patients stand and walk with support one day after surgery, using a walker or crutches.
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Daily lengthening process: Lengthening begins about 5 days after surgery. Patients place a handheld transmitter over the receiver under the skin. 3 sessions per day equal 27 impulses, which is about 1 millimeter of new bone growth. Patients can gain 6 centimeters in about 60 days or 8 centimeters in about 80 days. The surgeon monitors progress with regular X-rays and adjusts the pace if needed.
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Bone growth and consolidation: As the nail expands, it creates space in the bone. The body fills this space with new bone tissue. After reaching the desired height, lengthening stops. The new bone then hardens during consolidation. The surgeon checks with X-rays and confirms when the bone is strong enough for full weight-bearing.
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Walking and mobility: Patients can walk during the lengthening phase with the assistance of a walker or crutches. Unassisted walking and full weight-bearing are only possible when the bone is fully healed. The surgeon decides the timing based on X-rays and the patient's progress.
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Physiotherapy and rehabilitation: Daily physiotherapy is part of the treatment. Stretching, strengthening, and mobility exercises keep the joints and muscles flexible and help them adapt to the new bone length. The program continues during lengthening and consolidation until the patient regains full mobility and strength.
How much height can you gain with Fitbone?
With the Fitbone limb lengthening system, patients can gain up to 8 cm (about 3.1 inches) in the femur and up to 7 cm (about 2.7 inches) in the tibia. The achieveable height increase depends on your individual anatomy, the condition of your soft tissues (muscles, nerves, blood vessels), and how well your body adapts during the lengthening process.
Advantages of Fitbone
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Fully internal system: No external fixators, no risk of pin-site infections.
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Minimal scarring: Only four small incisions with a discreet cosmetic result.
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Safe and precise: Durable stainless steel nail provides controlled and reliable lengthening.
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Early mobility: Patients walk with a walker or crutches one day after surgery.
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Everyday comfort: Clothing, hygiene, and movement are less restricted.
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Bidirectional control: The nail can lengthen, and under surgeon guidance, shorten if medically necessary.
Fitbone femur nails are available in 9 mm, 11 mm, and 13 mm diameters, and tibia nails in 9 mm and 11 mm diameters to suit different anatomies.
Considerations and limitations
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Cost: Fitbone is more expensive than LON due to its advanced technology.
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Receiver use: The small receiver under the skin must be used correctly for the system to work properly.
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Weight-bearing: Full, unassisted walking is possible only after the bone has gained enough strength, as confirmed by your surgeon.
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Commitment: Following postoperative guidelines, daily physiotherapy and exercises are necessary for a safe and successful outcome.
Fitbone Leg Lengthening Timeline
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Day 1: Arrival and hospital admission
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Day 2: Preoperative examinations and blood tests
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Day 3: Surgery with the Fitbone internal lengthening system
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Day 4: Mobilization begins with standing and assisted walking using crutches or a walker
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Day 5: Start of exercises with gentle knee and hip movements
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Day 7: Discharge from the hospital. The distraction (lengthening) process starts
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Day 7-9: Structured physiotherapy program begins
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Day 10–90: Daily distraction phase, 1 mm per day (up to 7–8 cm possible)
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Day 90–150: Consolidation phase, bone gradually hardens, walking aids still required
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Day 150–365: Gradual progression to full weight-bearing and independent walking
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12–18 months: Removal of the nail in a short procedure after full recovery
Everyday Life With Fitbone
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Patients can wear normal clothing since the system is fully internal.
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The external transmitter is compact and easy to carry.
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Walking with aids (walker or crutches) is possible from the first days after surgery.
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Patients can manage most daily activities independently, with certain limitations.
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Air travel is possible, but a medical letter should be carried for airport security.
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Sports, heavy lifting, and high-impact activities must be avoided until full recovery.
Risks and Safety Information
Every surgical procedure carries some risks, and limb lengthening with Fitbone is no exception. Potential complications include infection, blood clots, delayed or premature bone healing, joint stiffness, muscle contractures, nerve irritation such as tingling or numbness, and implant-related issues that may require revision surgery. These risks are carefully managed by your surgical team through detailed planning, gradual and controlled lengthening, structured physiotherapy, and close medical follow-up throughout the process.
Is Fitbone the Right Choice for You?
Fitbone™ is best for patients who want a fully internal limb lengthening solution without external frames, prefer smaller scars, and are ready to commit to physiotherapy, regular follow-ups, and daily exercises. It is also a good choice if you want more independence, as you can walk with a walker or crutches during the lengthening phase.