Repeated occurrences of chronic overuse conditions despite the application of appropriate therapy can be an indication of leg length discrepancy (LLD). This condition, also known as short leg syndrome, is characterised by a notable difference in length between the lower limbs.
In Singapore, symptoms of LLD are often hard for patients to verbalise and thus frequently overlooked or mistaken for another condition. Most patients report “feeling uneven” or “having one hip higher than the other”, and these descriptions are often accompanied by a feeling of lower back pain.
Leg length discrepancy can be caused by:
- structural factors where there is a noticeable difference in the lengths of the femur/tibia in both legs
- functional factors wherein the bony components are equal in length but surrounding muscles function asymmetrically. This asymmetry may be caused by tight muscles in the waist, hips, or lower back, causing one hip to be higher than the other, and function or look different from the collateral side.
Parents should be more attuned to their children’s gait; any signs of limping, reduced hip swing or restricted hip movement should be investigated for LLD. Aside from LLD, these symptoms can also be a sign of other serious conditions such as a slipped femoral epicondylitis, avascular necrosis, fracture, tumour or scoliosis.
Structural LLD can be caused by:
- Congenital defects (unilateral coxa vara)
- Tumours or an underlying bone disease
- Paediatric hip concerns
- Trauma (Road traffic accident)
- Infection (polio)
- Post-surgical shortening
Functional LLD can be caused by:
- Soft tissue contractures
- Unilateral pronation
- Anterior rotation of the pelvis
- Pelvic torsion
Some studies have shown that as much as 90% of the population has some form of LLD.1 However, the majority of LLD cases in adults are thought to be of little clinical significance except in overuse conditions.
Overuse conditions include instances of increased stress during physical activity, which causes individuals to experience elevated symptoms. Furthermore, the longer leg often experiences increased loading during gait movement as the body naturally compensates for the imbalance in length while trying to keep the head level at all times. This typically results in symptoms appearing first or being more severe in the longer leg due to increased stance time and excess pronation, leading to pain and tension.
Signs and symptoms of leg length discrepancy
- Back pain
- Hip pain/Inter-tibial band syndrome
- Early-onset osteoarthritis
- Neurological pain
- Pronation of the subtalar joint
- Uneven shoulders
- Achilles tendinopathy
- Early heel lift
How do we diagnose Leg Length Discrepancy?
Podiatrists, or foot specialists are trained to differentiate between structural or functional LLD. During the initial assessment, a series of clinical tests will be conducted to identify any differences in leg length and other conditions. One of these assessments is conducted by measuring each leg length from bony landmarks and a Galeazzi’s test to identify if the length difference is in the femur or tibia. If there is a difference of more than 1 cm, or if presenting symptoms are causing pain, your podiatrist will advise you on what they can do to help.
If a child has noticeable leg length discrepancy (LLD), It is important to consult a podiatrist immediately as LLD can lead to adverse effects on a child’s gait in a long run.
How can we help?
Custom prescription orthotics will be used to rectify the difference in leg length. Your podiatrist will also help devise specific stretching exercises to target muscle groups in the waist, hips and lower back to help your body adjust to the new posture.
Differences in leg length between individuals can vary from 3mm to 6cm or more depending on the cause of LLD. If the LLD is from congenital limb deformities then specialised knee, ankle, foot devices, or customized footwear may be required to achieve the desired symmetry and rectification. Speak to your podiatrist for more information and to see if you are a suitable candidate for this.