(EN) Proportion and possible gain
(EN) Early resuming of sport like bike, even on the same day as the surgery.Read More
Proportions and possible gains
The lengthening process can be directed towards altering both stature and proportion. Proportions such as trunk, limbs and bone segments are objective and can be changed if the desired result is cosmetically attractive and surgically feasible. Selecting which bone to lengthen would depend on disease, discrepancy level, beauty standards and cosmetic viability. Muscle gain can also be used to cosmetically ‘disguise’ or add to the desired effect, so these options can be discussed.
Stature/Height and proportions
For men, average height is 1.76 m (5 feet, 9.5 inches) and for women 1.68 m (5 feet, 6.25 inches). In terms of anthropometrics, the length of the femur represents 29% of standing height, while the tibia represents 80% of femur length.
Generally, the length of the longer limb is referenced where one is shorter than the other. In cases of limb-length discrepancy, the limbs are made equal through treatment.
In cases of dwarfism, an increase in height aims to improve quality of life and daily function. Approximately 1.45 m (4 feet, 9 inches) is the minimum height that allows someone to drive a vehicle and reach buttons on everyday appliances. The most important thing in this case is to achieve additional height while maintaining proportions.
In those with short stature with no dwarfism (constitutional short stature), cosmetic lengthening can be performed. Here, the goal is to gain height while retaining correct body proportions.
Cosmetic lengthening can be performed for specific and personal reasons and as gains are usually smaller, proportions are generally maintained more easily.
Trunk versus lower limbs
Seated height represents 55% of a person’s standing height. Seated height is measured when a person sits on a wooden block with their back against a wall. The measurement is taken from the top of the head to the wooden block. This demonstrates that the trunk is taller than the lower limbs.
Beauty standards have changed and developed over time. A canon of beauty can be used to tell us what was historically considered ‘normal’ in terms of body proportions. A perfectly proportioned figure used to be a ratio of 6 to 1, meaning the head height made up one sixth of the body’s stature. Today, we use a ratio of between 7 to 1 and 8 to 1 with more emphasis on the leg length. Celebrities and Barbie dolls often represent this ‘ideal’ beauty canon and have very long, exaggerated legs.
We sometimes measure beauty against the golden ratio (1.618), where lower limbs are longer than the trunk. In women’s fashion magazines, female models are often digitally elongated for aesthetic effect.
It is often the case that patients become ‘disproportioned’ after a cosmetic lengthening, unless the legs were unusually short to begin with. Visually, this can be resolved with muscle bulking if necessary. A large localized gain (i.e. on the femur or tibia alone), doesn’t necessarily cause any proportional issues. In this case it is actually easier to maintain a desirable silhouette, especially where body-building is considered to alter the physique.
Femur or tibias ?
A tibia is 80% of the length of a femur. Both are viable options for lengthening, depending on the patient’s preferences. However, external measurements are unreliable and do not accurately gage the length of an individual segment of bone.
Females often prefer femur lengthening because wearing high-heeled shoes can cause proportional (aesthetic) issues after a tibia lengthening. Yet, wearing high-heels is not a problem after a femoral lengthening.
The matter of surgical feasibility is the other important factor to consider. The femoral cortex, which is where the bone’s strength lies is far stronger than the tibial cortex, so screws are more stable in the femur. However, when using external fixators, the distance between the bone and fixator is shorter in the tibia. This creates a more stable lengthening and decreases the chance of axial deviations. Surgeons therefore prefer the tibia in general for these procedures, wishing their patients to choose the more risk-free option.
The femur in the thigh doesn’t come into contact with the skin. But the tibia does touch the skin, which increases risk of infection, which is an important point to consider.
In case of delayed healing, the femur is more secure and femur fixation is stronger. This is because the cortical bone is harder in the femur, and softer in the tibia.
When considering the biological perspective, lengthening the femur means faster healing, faster recovery and minimised risk in terms of healing, infection deviation etc.
Bulking and Clothes disguising
By gaining muscle (bodybuilding), a patient can focus on particular muscle groups and complement the visual effect of a large gain on one specific level (i.e. the femur).
The lengthening procedure stretches muscles, which then need time to adapt to the bone’s new length. Muscles can only be built up once the bone is fused, which can take between 6 and 9 months depending on the gain (between 5 and 8 cm). Muscles are disproportionate before fusion, but bulking post-fusion can change this.
The image below shows how a perfectly proportioned person can gain 9 cm on femurs and still achieve a balanced and attractively physique.
Clothing can enhance the perception of proportions, so it is worth considering what effect this can have. A higher waist-band, for example, can make legs appear longer.