Leg length discrepancy: causes, symptoms and treatment options
A leg length discrepancy can be a significant problem for those affected, as it often leads to discomfort and restricted movement.
In this article, we shed light on the background to this medical phenomenon, explain the different causes and types of leg length discrepancy and provide a comprehensive overview of diagnosis and treatment options.
The aim is to provide those affected with a sound basis for better understanding the problem and finding suitable measures to alleviate the symptoms.
OVERVIEW
What is a leg length discrepancy?
There is a difference in leg length if there is a difference in length between the two legs.
This can have various causes and occur in different ways.
Those affected often suffer from restricted mobility and back pain, or have problems with poor posture.
A basic distinction is made between two types of leg length discrepancy:
Structural leg length difference
The so-called “true” leg length difference is congenital or is due to past infections, trauma or tumors.
It is caused by different lengths of the thigh and/or lower leg bones.
Functional leg length difference
Functional leg length discrepancies are caused by joint misalignments or contractures of soft tissue, muscles and ligaments.
Often one leg is permanently under more strain than the other or its muscle groups contract more strongly.
Postural problems can also cause pelvic obliquity.
Causes of different leg lengths
There are a variety of causes that lead to a difference in leg length.
The leg length difference often has a complex background, which can include both genetic and acquired factors.
Some cases of slight functional leg length discrepancies are not caused by asymmetrical bone growth, but by asymmetrical loading of the legs.
Misalignment of the spine – as in the case of scoliosis – can also cause pelvic obliquity, which results in a difference in leg length.
Congenital malformation of the hip joint (hip dysplasia) is also associated with problems with the position, which also causes a difference in leg length.
Anatomical leg length differences are caused by actually elongated or shortened sections of the skeleton.
Differences in the length of the leg bones can already be detected during growth.
Injuries to the growth plates of a growing skeleton can exacerbate malformations and cause differences in leg length.
Common causes of leg length discrepancies can be
- Muscular shortening
- Anatomical causes (e.g. foot deformities, paralysis, hip or leg deformities, growth disorders)
- Inflammation of the bone marrow due to infections
- Operations (e.g. on the hip joint)
- Laterally differentiated length growth after bone fractures
Symptoms and diagnosis
Symptoms: Pain and discomfort
A greater difference in leg length puts more strain on the musculoskeletal system, as the body has to compensate for the differences in length.
This often leads to pain in the lumbosacral region, as the pelvic rotation and tilt have to be compensated for by increased lordosis and rotation of the lumbar spine.
In patients with chronic lumbalgia, a difference in leg length can be detected in most cases.
Another way of recognizing a shortened leg is by the crooked position of the shoulder.
This is on the side of the longer leg.
A sideways tilt of the head towards the shorter leg can also be an indication.
Specialist diagnosis
The diagnosis of a leg length discrepancy begins with a detailed medical history.
The doctor asks about the patient’s complaints and medical history, including general and concomitant illnesses.
The orthopaedic surgeon then examines the patient and checks for asymmetries by visually inspecting and palpating the pelvic bones and spine.
The following steps are carried out as part of the investigation:
- Visual inspection: Check the symmetry of the skin folds and skin dimples above the sacrum as well as the height of the iliac crests when standing closed.
- Palpation: Palpation of the pelvic bones and spine to detect pelvic obliquity.
- Measurement of leg lengths: Measurement of the lengths from the iliac crest to the outer ankle. Comparison of leg length when lying down and sitting upright.
- Imaging procedures: If necessary, a whole-leg X-ray, CT or MRI scan is performed to obtain more precise results.
- 3D spine measurement: radiation- and pain-free reconstruction and measurement of the vertebral body position.
- Orthopaedic gait analysis: Assessment of pelvic obliquity by means of a gait analysis.
Treatment options for leg length discrepancy
Which treatment is suitable depends entirely on the causes, symptoms and anatomical conditions of the patient.
If the difference in leg length is less than 1 cm and there are no symptoms, treatment is not necessarily required.
If the difference is between 1-2 cm, the need for treatment must be assessed taking into account the patient’s medical history, age and extent of symptoms.
Leg length differences of more than 2 cm generally require treatment.
Conservative treatment
There are various treatment options for treating leg length discrepancies.
Conservative options include physiotherapeutic measures, orthopaedic insoles, heel raises, custom-made orthopaedic shoes with individual raises, orthoses or prostheses.
In some cases, surgery is also an option.
Surgical treatment
Surgical measures can vary depending on age and severity.
In patients who have not yet fully developed in adolescence, a leg length discrepancy is treated by so-called epiphysiodesis (the growth plate of the longer leg is manipulated in such a way that further growth is stopped).
In adult patients, a distinction is made between acute and chronic surgery.
Acute leg length correction
Acute leg length correction means that the entire difference is corrected in a single operation, with the bone being fixed in the desired position using plates, screws or nails.
Chronic leg length correction
Chronic leg length correction is performed more slowly and over a longer period of time, often by gradually lengthening or shortening the bone.
This can be achieved by using special devices such as fixators or lengthening intramedullary nails, which are then continuously adjusted.
The Ilizarov procedure or callus distraction, for example, can be used here.
This approach is often used for moderate differences in leg length, sometimes also in adolescent patients.
Which procedure is used depends on the extent and complexity of the deformity. If the difference in leg length is large or if there is a complex deformity, for example due to an additional twisting of the bone, chronic treatment is more suitable.
Exercises for prevention
To prevent a functional pelvic obliquity, it is important to have strong core muscles and good posture.
This can be achieved in particular by strengthening the abdominal and back muscles.
Preventive exercises include stretching exercises and targeted training of specific muscle groups to compensate for muscular imbalances.
A physiotherapist should first determine which muscle imbalances are present.
Stretching exercises should target the muscles that can shorten joints: the twin calf muscle and the gluteus maximus on the side of the shorter leg and the hip flexor on the side of the longer leg.
The back and inside of the thigh should be stretched equally on both sides.
However, stretching is not helpful if there is a real difference in leg length.
If you suspect you are suffering from a leg length discrepancy, do not hesitate to consult a doctor to avoid more serious consequences.
Early diagnosis of symptoms and targeted treatment are the key to a pain-free and active life.
As a doctor, I can help you find the best measures to correct and alleviate the pain.