Methods of Bone Fixation in Limb Lengthening

Precise-2 is the previous generation of PRECISE limb lengthening family of products.  Precise-2 was introduced by Nuvasive in 2012.

The main disantvantage of Precise-2 , compared to the newer Stryde, is that it  doesn’t allow full weight bearing post-operatively. Although this is reasonably well tolerated in case of unilateral limb lengthening, (or bilateral upper limb) it is not very comfortable and efficient in cases of bilateral lower limb lengthening such as for cosmetic reasons.

Because of Precise-2’s weight bearing restrictions, we now offer Precise-2 in selected cases  only and after appropriate consultation. ( See more in Limb Lengthening Options and Financial Considerations.)

G-Nail is based on the successful design of Albizzia nail which was introduced to clinical practice by Dr Guichet in the USA in 1991. The current version of G-nail was developed in 2010 and has been in clinical use continuously since 2010.

G-nail is made of hardened stainless steel, Chromium and Cobalt alloy. This alloy is one of the most well studied and most commonly used in orthopaedic implants of all sorts. It has uninterrupted CE Mark approval in the EU since 2010. No signs of osteolysis related to metal debris and corrosion has ever been recorded and the CE mark was never withdrawn.

G-nail allows full weight bearing with crutches from the day of the surgery.

G-nail allows lengthening of the first 1 cm of lengthening on the day of surgery thus reducing the overall duration of the lengthening period.

G-nail doesn’t require external electrically powered appliances for the lengthening which makes early repatriation of patients at 6 weeks after surgery logistically easier (no need for technical support of the appliance, no problems with customs clearance of the appliance during traveling, no problems with incompatibility with electrical networks in different countries)

More than 700 nails have been implanted so far. The reported mechanical failure rate is less than 2% and the non-union rate is also less than 2%. With the newer anaesthetic protocols pain during  performing lengthening manuevers is non-existent or minimal.

An additional advantage of Axos instrumentation is that the femoral osteotomy is performed with the intramedullary low energy saw, allowing the surgeon to do the surgery with less skin incisions.

IMPLANT TEMPORARILY RECALLED BY THE MANUFACTURER. NOT AVAILABLE UNTIL FURTHER NOTICE.

STRYDE nail is an internal fixation device;this means there is no hardware outside of the body.

It is inserted percutaneously through small stab incisions  and it is locked with screws  below and above the osteotomy in order to provide rotational stability.

Right femur, Stryde nail, 2.5 months after surgery

The newly released STRYDE Limb Lengthening and Compression System represents Nuvasive’s  latest advancement in the PRECICE family of implants.  This 3rd generation advanced solution builds upon the reputation and efficacy of the PRECICE proprietary technology.

Stryde was commercially released in 2018 and introduced in the European Union in January 2019. Athens BJR hase been one of the first centres that the nail became available to.

Stryde is made of stainless steel. STRYDE Benefits include:
• 400% increased post-operative weight bearing (vs. PRECICE)
• Reinforced internal mechanism
• Customizable lengthening protocol
• Novel PRECICE magnetic technology
• Up to 80mm of distraction
• Nail may be reversed

The key to the NuVasive platform technology is the magnetic interaction between the PRECICE STRYDE intramedullary nail and remote control. The proprietary technology includes a complex internal gear system remotely activated and controlled by permanent magnets. This 3rd generation advancement in limb lengthening and compression allows for precision control and the ability to non-invasively customize treatment.

External Remote Controller (ERC)
The ERC is a portable, hand held unit that precisely lengthens or shortens the STRYDE nail through the touch of a button. The ERC prescription is customized by the physician to meet the needs of each patient. The ERC is
designed to be used in a clinic setting or from the comfort of the patient’s home.

STRYDE Weight bearing properties : 150lbs for the 10.0mm diameter
implant, 200lbs for the 11.5mm diameter implant and 250lbs for the 13.0
mm implant.

References

1. Data on File. PRECICE STRYDE Max Patient Weight Assessment. Report LR0838-1
2. Herzenberg JH, Standard SC, Specht SC. Limb lengthening in children with a new,
   controllable internal device. European Paediatric Orthopaedic Society (EPOS);
   April 17-20, 2013; Athens, Greece.

Since the 1970s, several intramedullary lengthening nails have been developed to avoid various complications caused by long periods of external fixation.

The following devices have been the most clinically known: the Fitbone® (WittensteinIntens, Igersheim, Germany),  the Intramedullary Skeletal Kinetic Distractor (ISKD®; Orthofix Inc., Lewisville, Texas, USA), Biliskunov nail.

However, many of these have showed some issues associated with the lengthening mechanism or strength of the nail which resulted in nonoptimal results.

These implants heve not been used in our centre and are not offered to our patients. They are mentioned here for the purpose of completeness only.

References.

DH Lee,  S Kim, JW Lee, H Park,T Y Kim, and HW Kim.  A Comparison of the Device-Related Complications of Intramedullary Lengthening Nails Using a New Classification System. Hindawi,BioMed Research International, Volume 2017, https://doi.org/10.1155/2017/8032510

This section is under construction.

References

This section is under construction.

Limb lengthening with purely external fixation devices entails that the frame has to remain in situ for the whole consolidation period leading to frame times of up to 2 months per cm of lengthening. This prolonged time in a frame confers several disadvantages. First, there is a greater chance of complications like pin-tract infection and decreased range of motion in the surrounding joints. Second, it may have a psychological effect on patients, increasing frustration and decreasing compliance. Finally, when the frame is removed, there is an 8 to 9.4% reported risk for fracture of the regenerated bone due to the lack of any internal stabilization.

LATN was introduced as an idea to reduce the external fixator time and avoid some of the reported  limitations and risks of LON including infection, need for acute deformity correction when a deformity is present and inability to distract the bone and achieve the desired lengthening.

External fixation is used for lengthening during the distraction phase and when lengthening is completed then the patient is taken back to theatre and  an intramedullary nail is inserted and the frame is removed. The external fixator is applied so that an intramedullary nail can be inserted while the frame is in place, however, without contact between the internal fixation and the external fixation pins and wires.  Once length has been achieved, a reamed locked intramedullary nail is inserted across the regenerate bone and the frame is removed. The intramedullary nail supports the bone during the consolidation phase allowing removal of the external fixator after the distraction phase of lengthening.

LATN is now the preferred method (instead of LON) in our centre for bilateral cosmetic tibial lengthening, when purely internal methods are excluded because of financial and funding limitations or when simultaneous correction of bone deformitiy is required.

References
S. Robert Rozbruch, MD, Dawn Kleinman, BA, Austin T. Fragomen, MD, and Svetlana Ilizarov, MD. Limb Lengthening and Then Insertion of an Intramedullary Nail: A Case-matched Comparison. Clin Orthop Relat Res. 2008 Dec; 466(12): 2923–2932.

LON is now used in our center only in cases of unilateral femoral or tibial lengthening after appropriate counselling , when purely internal methods are excluded because of financial and funding limitations.

LON was introduced as an idea to reduce the time spent on an external fixator and the related problems. External fixation is safe, but the consolidation phase tends to take too long.  The prolonged fixator time puts the patience of the patient to the test and, when applied to the femur, this prolonged duration tends to increase knee stiffness.

Moreover, eccentric loading of bones in the limb creates a  tendency for axial deviation of the regenerate and malunion.  Loosening of the fixation pins, instability of the fixator and tightness of muscles increase the tendency for axial deviation in the lengthening phase.

Combining IM fixation with the Ilizarov fixator firstly adds to the stability of the construct. The next benefit of the addition of the IM nail is the prevention of axial deviation during the fixation period and also after removal of the fixator over the long term. This was proved in our series with very low rates of axial deviation.

The greatest concern with LON technique has been the risk of deep bone infection due to close proximity of external pins and the nail. With great care in pin insertion and postoperative care we have not faced this problem in our series. However, the literature has mentioned this problem in the series of Simpson who had three deep infections in twenty LON surgeries. Kristiansen reported giving up on this method to revert back to the Ilizarov technique due to many complications.

The surgical technique of the LON procedure include:

• Preparation (drilling holes) of the osteotomy site.
• Completion of reaming of the intrmedullary canal (to prepare it for the nail).
• Partial application of the external frame (with reamer insitu as a reference to guide external pins and wires clear from the nail.)
• Completion of osteotomy.
• Insertion of the nail and proximal locking only.
• Completion of external frame construct as needed

When the distraction phase is completed, the patient is taken back to theatre where the  nail is locked distally with to screws and the external frame is removed. This is a minor procedure which is done as a day case and the patient leaves the hospital on the same day.

References

1. Chaudhary M. Limb lengthening over a nail can safely reduce the duration of external fixation. Indian J Orthop. 2008 Jul-Sep; 42(3): 323–329.
2. Paley D, Herzenberg JE, Paremain G, Bhave A. Femoral lengthening over an intramedullary nail: A matched-case comparison with Ilizarov femoral lengthening. J Bone Joint Surg Am. 1997;79:1464–80.
3. Min WK, Min BG, Oh CW, Song HR, Oh JK, Ahn HS, et al. Biomechanical advantage of lengthening of the femur with an external fixator over an intramedullary nail. Pediatr Orthop B. 2007;16:39–43.
4. Simpson AH, Cole AS, Kenwright J. Leg lengthening over an intramedullary nail. J Bone Joint Surg Br. 1999;81:1041–5. 
5. Kristiansen LP, Steen H. Lengthening of the tibia over an intramedullary nail, using the Ilizarov external fixator: Major complications and slow consolidation in 9 lengthenings. Acta Orthop Scand. 1999;70:271–4.
6. Kocaoglu M, Eralp L, Kilicoglu O, Burc H, Cakmak M. Complications encountered during lengthening over an intramedullary nail. J Bone Joint Surg Am. 2004;86:2406–11.

HYBIEX tibia lengthening is a combined method of bilateral tibial lengthening which utilizes Precise-2 nail on one side and LATN with circular frame on the other side.

Indications

HYBIEX is indicated for patients who:

1. Cannot tolerate confining themselves on a wheelchair during the lengthening and early consolidation periods (i.e with Precise-2 nails).
2. Cannot tolerate bilateral external frames in their legs.
3. Are not amenable to Stryde nails becuse of narrow intramedullary canals of their tibias or they cannot financially afford Stryde.

How it is done
HYBIEX is done in two stages.
1.Stage one: Tibia osteotomy and IM nailing with Precise-2 nail on one side (Left or right is agreed with the patient pre-operatively) and tibia osteotomy and application of external circular frame on the other side. Latency period and lengthening as per standard tibia lengthening protocol (10 days with 1mm per day and then 0.75mm until completion of lengthening).
2. Stage two: Upon completion of lengthening, return to the operating room and IM nailing of the leg with the frame with a standard fracture tibia nail (Synthes expert tibia nail from Depuy Johnson & Johnson) and removal of the external frame.

Advantages of HYBIEX compared to Bilateral Precise-2 or Bilateral frames, LON, LATN
1. More independent mobilization than with two Precise-2 nails. HYBIEX allows walking with full weight bearing on the frame side and toe touch weight bearing on the Precise-2 side with crutches from the first day after the surgery. No need to be bound on the wheelchair for 5 months.
2. Having only one frame is far more convenient, comfortable and safer than having two frames! Having just one frame  means half the risk of deep infection and pin site infection compared to having two frames for bilateral LON or LATN.
3. Immediate mobilization means less need for long term blood thinners compared to bilateral Precise-2 nails.
4. Theoretically reduced risk of fat embolism because the nailing is not done on the same day on both sides.
5. Easier to maintain privacy about the clinical reason for lengthening because the treatment doesn’t look “similar” or “symmetrical” on both sides (applies especially in cosmetic cases, where patients often don’t wish to disclose the real reason of their treatment).

Disadvantages of HYBIEX compared to bilateral Precise-2 or Stryde nails:

1. All external or combined methods  carry a slightly increased risk of deep bone infection compared to all internal methods.  The risk  of deep bone infecton with nails is around 1% whereas with LATN is 2-2.5 %.
2. Need for one additional surgery (removal of frame and nailing at the end of the lengthening period).

Disantvantages of HYBIEX compared to bilateral external frames
1. HYBIEX is  more expensive.