Limb lengthening is a surgical procedure that involves the gradual lengthening of a patient’s bone to increase height. This procedure involves several distinct phases that are essential to ensure a successful outcome. Understanding the different phases of limb lengthening is crucial for both patients and medical professionals involved in the procedure. In this article, we will discuss the four phases of limb lengthening: the surgical phase, the latency phase, the distraction phase, and the consolidation phase. By providing a comprehensive overview of each phase, we hope to enhance your knowledge of this procedure and help you prepare for a successful limb lengthening experience.
The surgical phase of limb lengthening is the initial stage of the procedure. During surgery, the surgeon cuts the bone to create two separate bone segments. The surgical procedure to cut a bone is called an osteotomy. In limb lengthening surgery, after the bone is cut through an osteotomy, the surgeon applies an orthopedic lengthening device to the bone. These devices can be either internal or external. Internal devices, such as the Precice nail, are inserted directly into the bone. External devices, such as monorail or circular frame, remain outside of the body and are attached to the bone through pins or wires. The surgical phase requires careful attention to detail. To ensure the safety and success of the limb lengthening procedure, it is crucial to have a skilled and experienced surgeon performing the surgical phase.
The limb lengthening latency period is also known as the distraction-free interval, and it allows the bone to heal and prepare for the lengthening process. There is no lengthening in the latency phase and the callus formation is waited for to begin. It usually takes 5-10 days.The duration of the latency period can vary depending on various factors such as age, overall health, and the specific bone being lengthened. It is important to determine the appropriate duration for the latency period to avoid complications such as premature consolidation or bone non-union.
Lengthening (Distraction) Phase
During the lengthening period, the bone segments are gradually separated from each other. The slow separation of bone segments stimulates the body to produce new bone (callus). The rate of distraction is typically about 1 mm per day, though it may vary depending on the bone being lengthened. The rate of distraction may need to be adjusted based on the appearance of the regenerated bone(callus) on X-rays, and the patient need to see the doctor several times a month to ensure the bone is lengthening at the appropriate rate. Regular x-rays every two weeks are necessary to assess the quality of lengthening and ensure no complications arise. When bone lengthening begins, the soft tissues around the bone also need to lengthen. The lengthening capacity of the soft tissues is not very fast, so this process can result in tension and discomfort in the soft tissues. For this reason intense physical therapy require at least five times per week during the distraction phase.When the target length is reached, the lengthening is stopped and the consolidation phase begins, in which the new bone tissue becomes denser and hardened.
The phase during which the newly formed bone tissue within the osteotomy gap consolidates and becomes hardened is referred to as the consolidation period. After the bone has been lengthened to the desired length, the new bone needs time to consolidate and strengthen. Regular x-rays are necessary to assess the progress of consolidation. Depending on individual parameters, full weight-bearing is usually allowed between 4 and 8 weeks after the end of the lengthening phase. Physiotherapy should also continue during the consolidation phase with a focus on muscle strengthening, re-education, and improvement of limb proprioception. The intramedullary nail can be surgically removed from the bone when the new bone tissue is fully consolidated and can bear body weight in any activity. This period usually lasts 1-1.5 years after surgery.