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Equal Length of Lower Limbs is Important
Discrepancy in the length of lower limbs resulting from excessive growth, growth inhibition of bones, congenital defects, or trauma is not always problematic. However, if the difference in limb length exceeds 1 cm, causing the patient to limp and experience pain, it is essential to consult a specialist. This is important because unequal limb length can lead to several significant early and long-term consequences, including lateral spinal curvature (scoliosis), joint mobility restrictions, hip joint dysfunction, bursitis, axial deformities of the knee joint, and in later life, the development of degenerative joint changes or Achilles tendon contracture.
Who Qualifies for Limb Lengthening Surgery
Candidates for limb lengthening surgery include children with a minimum lower limb discrepancy of 2 cm caused by conditions such as congenital defects (e.g., congenital absence of the fibula, congenital femoral deficiency), growth plate fractures, childhood bone infections, or unknown causes (idiopathic). Patients with dwarfism may also qualify, as simultaneous lengthening of both lower limbs can significantly increase height. The procedure can also be performed on children and adults who have experienced bone healing in a shortened and deformed position due to trauma.
How Does the Bone Lengthening Process Work?
The bone lengthening process begins with osteotomy, which involves cutting through the cortical layer of the bone while leaving the bone marrow intact. This creates two bone segments. At the same time, an orthopedic device for bone lengthening is installed. This device can either be an intramedullary nail (e.g., PRECICE or FITBONE) placed inside the bone or an external fixator, such as the Taylor spatial frame or Ilizarov apparatus, attached to the outside of the body. Within 5-7 days after surgery, the repair processes begin between the bone segments.
After this initial period, the process enters the distraction phase, during which the bone segments are gradually separated. The gap created is filled with newly formed bone tissue called the bone regenerate. During this phase, the device is adjusted daily, slowly increasing the distance between the bone segments at a rate of approximately 1 mm per day. The distraction phase not only facilitates bone formation but also stretches soft tissues such as muscles, nerves, blood vessels, and skin. The growth rate is carefully monitored by a physician, making regular follow-up visits (approximately every two weeks) necessary.
During the lengthening process, the patient undergoes rehabilitation and performs exercises at home. It is also important for patients to maintain a healthy lifestyle and take recommended vitamin and supplement preparations. The distraction phase continues until the desired bone length is achieved, with patients required to engage in a minimum of 4 hours of rehabilitation daily.
The next stage is the consolidation phase, during which the bone regenerate gradually hardens and transforms into mature bone. This phase lasts an additional 2-3 months, during which the bone lengthening device remains in place. Once the remodeling and calcification of the new bone are complete, the lengthening device can be removed. External fixators are typically removed after 4-6 months, and in some cases, conversion to an intramedullary nail for bone stabilization may be necessary. For intramedullary nails, removal occurs approximately 1-1.5 years after the initial surgery.
Internal Limb Lengthening
Lower limb bone lengthening surgery involves significant discomfort as it requires considerable intervention in the patient’s body. The least invasive procedure, involving a few small incisions, is internal bone lengthening using expandable intramedullary nails. This method involves placing a lengthening nail (e.g., PRECICE or FITBONE) inside the bone, within the medullary canal. This specialized telescopic rod is equipped with a mechanism activated by magnetic fields or electrical impulses, controlled externally to facilitate gradual nail elongation.
The surgeon uses a specialized drill to prepare the bone for nail placement. The insertion method depends on the patient’s individual characteristics and the bone being lengthened. For the femur, the device may be inserted from the top (near the pelvis) or the bottom (near the knee). For the tibia, the nail is inserted from the knee. After surgery, the patient stays in the hospital for 2-3 days and subsequently attends follow-up visits every two weeks during the distraction phase. During the consolidation phase, until the bone fully heals, follow-up visits occur once a month.
Throughout both phases of the limb lengthening process, high-intensity physiotherapy is essential to accommodate the lengthening of not only the bone but also soft tissues such as tendons and muscles. Physiotherapy is a crucial component to minimize the risk of complications associated with limb lengthening. The nail is typically removed approximately 18 months after implantation.
External Fixators
In cases where the medullary cavity of the bone is too small to accommodate an intramedullary nail during lower limb lengthening, external fixation is necessary. This involves a type of metal framework encasing the lower limb and attached to the bone using pins or screws. External fixators are used for both bone lengthening and correcting bone deformities. They come in two forms: monolateral (a single-sided bar) and circular.
The implantation of an external fixator, like intramedullary nails, requires a minimally invasive percutaneous osteotomy. Lengthening in this case is performed manually by the patient or their caregiver, following medical instructions. Intensive rehabilitation is also essential, as with intramedullary nails. Proper daily care of the external fixator is crucial to minimize the risk of superficial or deep infections around the pins or screws securing the device to the bone.
Possible Side Effects
- Postoperative wound infections,
- Deep vein thrombosis or pulmonary embolism,
- Nerve and blood vessel damage,
- Pain,
- Issues with bone tissue remodeling,
- Restricted range of motion in joints adjacent to the lengthened bone.
Cosmetic Limb Lengthening
Short stature is a significant concern for many individuals. Fortunately, modern medicine has made substantial advancements in addressing short stature. Orthopedic advancements now enable limb lengthening to achieve additional height while maintaining proportions appropriate to the patient’s body and needs.
The PRECICE/FITBONE technology allows for femoral lengthening of up to 7-8 cm. By combining this with tibial lengthening (up to 5 cm) in a subsequent stage, a total height increase of 12-13 cm can be achieved. However, not all patients are eligible for this combined procedure. The extent of lengthening depends on the patient’s bone and soft tissue characteristics. Importantly, the planned lengthening is determined during preoperative planning and may be adjusted during the process without affecting the overall treatment duration.
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References:
- The Journal of Bone and Joint Surgery. British volumeVol. 88-B, No. 7 - The results of limb lengthening by callus distraction using an extending intramedullary nail (Fitbone) in non-traumatic disorders - S. Singh, A. Lahiri, M. Iqbal
- Lower limb lengthening and deformity correction using the Fitbone motorized nail system in the adolescent patient - AL-Sayyad, Mohammed J. - Journal of Pediatric Orthopaedics B: March 2012 - Volume 21 - Issue 2 - p 131-136
- Bone lengthening using the Fitbone® motorized intramedullary nail: The first experience in France - F.Accadbled, R.Pailhé, E.Cavaignac, J.Sales de Gauzya - Orthopaedics & Traumatology: Surgery & Research - Volume 102, Issue 2, April 2016, Pages 217-222
