Kevin M. Wong, DC
According to Yale Medicine, it is quite common for people to have slight differences in leg length that they never notice. Columbia University Orthopedics indicates that a majority of people in the world have some degree of leg-length discrepancy of up to 2 cm. A study by Vogt, et al.,1 found that only around 25% of people have legs of equal lengths. The greater the discrepancy, the greater the chances of having a clinical problem down the road.
Symptoms of LLD include limbing, abnormal gait, posture problems, hip and back pain, a hyperextended knee on the short side and flexed on the long side, and fatigue.2 While small discrepancies may be asymptomatic, larger differences can lead to issues such as back pain, hip pain, and altered gait. A limp usually begins when LLD exceeds 2 cm and becomes extremely noticeable above 3 cm.
A Crucial Clinical Distinction
Proper clinical diagnosis is crucial to determining the type and extent of the discrepancy. Understanding the differences between the types of LLD is critical. LLD is classified into two types: structural (anatomical) and functional.3
Structural (anatomical) LLD occurs when there is a physical difference in the length of the bones. To determine if there is a quantifiable LLD, one can use the True Leg Length method.
Functional LLD arises from postural issues, muscular imbalances, or joint misalignments of the ankles, knees, hips, pelvis, and spine. The Derifield Leg Check or the Apparent Leg Length Measurement can be used here.
Adjust the Patient First!
Whatever type of LLD the patient has, evaluating and adjusting the patient’s ankles, knees, hips, pelvis, and spine is crucial. Often, the LLD we encounter in practice is functional and can be leveled up or significantly reduced through chiropractic adjustments. This helps prevent a practitioner from using an unnecessary heel lift and sets the stage for proper usage of custom scanned/casted, flexible, three-arch orthotics to provide a stable foundation for the feet and the spine.
Orthotics vs. Heel Lifts: Appropriateness
Often, chiropractors treat a patient, and we observe the use of a heel lift when unnecessary; in other words, once the DC has adjusted the patient, the legs/heels go even, and the lower extremity and pelvis appear balanced. If the patient’s feet are level and even, no heel lift is necessary.
Situations arise in which the LLD remains even after the chiropractic adjustments have tried to level up the lower extremity and spine as much as possible. Here, one can still observe and measure the difference between the two heels.
In this case, have the patient wear the custom, flexible three-arch orthotics for two weeks. These types of orthotics will absorb 1-3 mm of LLD and often negate the use of a heel lift.
What Type of Lift Should Be Used?
The rule of thumb for using heel lifts is to measure the difference between the two heels, divide that number by two, and place the proper-size heel lift under the orthotic on the shorter leg.
Use the heel lift/orthotic combination for two weeks and then re-evaluate the patient to see how their symptoms and LLD are responding favorably. If necessary, progress to the next-size heel lift for another two weeks until the desired effect for the patient is achieved.
Benefits of Heel Lifts
Heel lifts are inserts placed inside the shoe, under the orthotic, to elevate the shorter leg, thus balancing the length discrepancy. The benefits of using heel lifts include:
- Improved Posture: By correcting the leg length, heel lifts help maintain a balanced posture.
- Reduced Pain: Alleviating the uneven pressure on the body can reduce pain in the lower back, hips, and knees.
- Enhanced Mobility: Correcting the leg-length discrepancy can improve gait and overall mobility.
Order the Orthotic With the Heel Lift, or Gradually Add the Lift?
Frequently, a partial heel lift is built-in (permanent), and an adjustable lift can be attached underneath with Velcro to accommodate a more significant anatomical LLI. Usually, the highest lift is 7 mm, so more than 7 mm can be added if some of the lift is built in and the rest is attached externally.
What Lift Height Is Too High for a Shoe?
The appropriate height of a heel lift depends on the specific needs of the individual, the orthotic being used, and the type of shoes being worn.4 However, there are general guidelines to help determine when a heel lift might be too high for a shoe:
Comfort and Fit: The heel lift should not compromise the shoe’s comfort and fit. If it causes the shoe to feel too tight or if the patient’s foot feels cramped, the lift may be too high or can’t be used in that particular shoe.
Shoe Design: Most casual and athletic shoes can accommodate heel lifts up to 12-13 mm without significant issues. Beyond this height, it might be challenging to achieve a comfortable fit without modifying the shoe or using a shoe specifically designed to accommodate higher lifts.
Balance and Stability: A heel lift that is too high can affect balance and stability, increasing the risk of falls or injuries. Generally, lifts higher than 12 mm should be used with caution.
Gradual Increase: For significant leg-length discrepancies, it is often recommended to gradually increase the height of the heel lift, rather than using a high lift all at once. This allows the body to adjust to the change more comfortably.
Potential Issues to Consider:
- Discomfort: If the patient experiences discomfort, it might be due to an incorrect height or improper placement. Have them revisit the fit with you and adjust as necessary.
- Shoe Fit: Heel lifts may affect shoe fit. Recommend that the patient opt for shoes with removable insoles to accommodate the custom orthotics and lift them better.
- Wear and Tear: Heel lifts can wear out over time. To maintain their effectiveness, suggest that the patient regularly inspect them for signs of wear and replace them as needed.
Clinical Takeaway
The correction or alleviation of the symptoms of LLD does not have to be complicated. Utilizing chiropractic to reduce the spinal and extremity misalignments; prescribing proper custom scanned/cast, flexible, three-arch orthotics; and adding a heel lift if and when appropriate will help you and your patient successfully navigate the LLD phenomenon.
References
- Vogt B, Gosheger G, Wirth T, et al. Leg length discrepancy - treatment indications and strategies. Dtsch Arztebl Int, 2020 Jun 12;117(24):405-411.
- Brady RJ, Dean JB, Skinner TM, Gross MT. Limb length inequality: clinical implications for assessment and intervention. J Orthop Sports Phys Ther, 2003 May;33(5):221-34.
- Defrin R, Ben Benyamin S, Aldubi RD, Pick CG. Conservative correction of leg-length discrepancies of 10mm or less for the relief of chronic low back pain. Arch Phys Med Rehabil, 2005 Nov;86(11):2075-80.
- Havran M, Scholten JD, Breuer P, et al. Deconstructing chronic low back pain in the older adult - step-by-step evidence and expert-based recommendations for evaluation and treatment: Part XII: leg length discrepancy. Pain Med, 2016 Dec;17(12):2230-2237.
