Guichet Nail (G-Nail)

The nail is two metal tubes, one sliding inside the other. Twisting the leg turns one tube against an internal ratchet, and each notch lets the nail out by one-fifteenth of a millimetre. That is the click you hear and feel. Dr Guichet's own site describes the routine plainly: 15 clicking movements produce 1 mm, performed as five clicks three times a day, muscles relaxed, hip and knee usually in slight flexion. His 2003 paper in the Journal of Bone and Joint Surgery used the same figure, fifteen alternating internal and external rotations per millimetre. The rotation needed per notch is about 20 degrees, according to the Freiburg institute that builds its own Albizzia-derived nail on the same principle.

There is no remote control, no magnet and no battery. You, a relative or a physiotherapist perform the movement. That independence is the selling point. It is also the weak point: the movement has to be repeated about 900 times for a 6 cm gain, and it hurts some people badly enough that they cannot finish it without help.

This is a European device with a European footprint. The inventor, Jean-Marc Guichet, currently lists consulting rooms and operating hospitals in London and Milan on his site; the site's patient stories also describe surgery and nail removal in Marseille. Beyond his own practice, a clinic in Athens listed on this site offers the nail under the name X-os G-nail and describes it as CE-marked in the EU since 2010. The published Albizzia series came from Nancy, Montpellier, Madrid and Salford. None of the 64 US clinics or 22 Turkish clinics on this site list it.

It suits a patient who wants an internal nail without weight-bearing restrictions and who is prepared to do the clicking personally, every day, for two months or more. The inventor's site is candid that the femur takes priority in bilateral cases and that the tibia heals less well, with some tibias needing a bone graft. A patient with low pain tolerance, or nobody at home to help with the rotations, should think hard before choosing a rotation-driven nail.

Clicking starts around day five and runs at 1 mm a day, the rate Guichet described in 1999 and the Madrid group used across its 24 femora. The Athens clinic states it takes the first centimetre in the operating theatre to shorten the lengthening phase. The inventor's site puts a 6 cm femoral gain at about two months of clicking and gives the femoral ceiling as 10 cm, more only with a nail exchange.

Published gains sit well below that ceiling. Guichet's 2003 series averaged 6.3 cm in bilateral stature cases (range 4.6 to 8.4 cm) and 3.4 cm in unilateral discrepancy cases. Acharya and Guichet's 27 bilateral cosmetic patients averaged 6.2 cm. Montpellier averaged 4.7 cm across mixed indications.

Walking: the inventor's protocol allows crutch-assisted support from day one and full support before lengthening ends, with a warning that unrestricted walking can wear the internal screw and stop further lengthening. The nail comes out after the bone has consolidated, a second operation followed by two to three weeks on crutches because the empty screw holes weaken the bone.

Three problems recur across Albizzia-family series; none exist with a magnetic nail.

First, pain during clicking. Guichet's own 2003 paper reported ratcheting under general anaesthesia in 13 of 41 femora. In the independent Montpellier series, 8 of 36 patients needed at least one ratcheting under anaesthesia, and three lengthening programmes failed outright. Calder's 2017 historical review in Injury states that the motorised Fitbone was developed precisely to remove the pain of the manual leg rotation the ratchet requires.

Second, premature consolidation. The inventor's site describes a window two to three weeks after surgery when bone forms so fast that clicking becomes 'very difficult, if not impossible', needing a brief anaesthetic to force a few clicks or, if caught late, a new operation to cut the bone. The Salford series saw premature consolidation in 4 of 8 femora.

Third, the opposite: uncontrolled movement. Salford also reported one runaway lengthening and a bent nail. Any twist can advance the ratchet, so the mechanism that lets you lengthen at home can also lengthen when you did not intend it. The ordinary internal-nail risks of non-union and hardware failure sit on top of all three.

Thin, and old. PubMed returns seven results for 'Guichet nail' and eleven for 'Albizzia nail' (searched September 2026), not all of them relevant; the relevant papers date from 1997 to 2012, and the largest is Guichet's own 31-patient series. The independent series are small: 36 femora in Montpellier, 24 in Madrid, five Albizzia nails in Salford. We found no peer-reviewed series of the current Guichet nail, the version a clinic will actually implant today.

Compare that with the magnetic nails. The 2020 Bone & Joint Research systematic review of cosmetic stature lengthening pooled 795 patients across 11 studies, and not one used an Albizzia or Guichet nail. Frost's 2023 multicentre cohort of 314 lengthening nails covered Fitbone and PRECICE only. The internal-nail complication ranges quoted elsewhere on this site do not transfer to this device.

What the old data does say is consistent. Knee motion is well preserved: mean flexion was unchanged at about 148 degrees in 27 bilateral patients. Consolidation ran at 35 days per centimetre in Madrid. And patients averaged three operations per limb in Guichet's own cohort, counting insertion, removal and anything in between.

Ask four things.

Who does the clicking when it hurts? A clinic that says pain is 'non-existent or minimal' should also tell you how many of its patients needed an anaesthetic to ratchet. The inventor's own site allows for a brief general anaesthetic when clicking stalls; a clinic that never mentions this is leaving something out.

Where are the numbers published? The Athens clinic's page states a mechanical-failure rate 'less than 2%' and a non-union rate 'less than 2%'; the inventor's site states a 67 mm average. Neither figure appears in a peer-reviewed journal as far as we could find. Ask for the paper. If there is none, the number is an internal audit at best.

Which version of the nail, and who made it? The Guichet nail replaced the Albizzia; the Athens clinic calls its implant X-os. Ask for the CE certificate and for the surgeon's personal count with this specific nail.

What happens if it stalls? Get the plan for premature consolidation and for a bent or jammed nail in writing, including who pays for the second operation and where it happens if you have already flown home.