Improve Patient Care and Grow Your Practice: Address the Short Leg

What if you could genuinely help improve existing and new patient outcomes while dramatically increasing compliance; yet add no extra hard costs to your practice and only 10 additional minutes to a typical treatment plan? In our practice, 35-40 percent of cases present with a short leg. The corrective results, functionally and structurally, are often astonishing. Correcting even as little as a 5 mm LLD in very fit patients creates a significant positive effect.

A Refresher: What Is a Short Leg?

Leg-length inequality or leg-length discrepancy (LLD) is well-documented in the literature, but grossly under-evaluated. There are two types of discrepancies: functional LLD and structural (true) LLD. A functional LLD occurs as a result of muscle imbalances, pelvic torsion or other mechanical reasons. The adjustments you already make positively address this.

An anatomical short leg is due to several orthopedic or medical conditions. Often, one growth plate closes before the other. Still unknown why this occurs, various studies report that between 25-50 percent of the population demonstrates a true LLD. Other causes include trauma, broken bones, surgical repair, joint replacement, radiation exposure, tumors or LCP [Legg-Calve-Perthes] disease.

The effects of a short leg depend upon the individual and the extent of discrepancy. The most common manifestation is a lateral deviation of the lumbar spine toward the short side, vertebral body rotation, and compensatory curves that can extend to the neck and even impact the TMJ. Studies have shown that A-P curve abnormalities can result, too. More significant are the biomechanic and kinematic changes that occur in patients, leading to chronic back and sacroiliac joint pain. Altered gait is particularly significant for athletes and runners who do not correct the LLD.^1-2

Idiopathic scoliosis accounts for less than 4 percent of the population. A recent study reported that 94.4 percent of idiopathic scoliosis patients demonstrated improves curves when appropriate measures were taken to correct LLD.³ This means that the majority of scoliosis cases are not really idiopathic!

Clues: Clinical Presentation

Patients may experience few or no symptoms prior to the age of 25-35. The most common symptom is chronic LBP, but frequent mid- and upper-back pain, and neck, hip or knee discomforts, are common subjectives. Same-sided and repeated injury, or pain to the hip, knee and/or ankle, is a hallmark of a long-standing untreated LLD. Many patients explain that chiropractic helps, but adjustments don't hold.

Marketing Flash: Use Social Media, the Web and Literature to Encourage Home Screening

It's easy for patients to evaluate whether they may have a short leg:

• Look in the mirror: Are the shoulders and collarbone even, or is one higher than the other?
• Does the head tilt to one side? (Look at the earlobes.)
• Does one hip or kneecap appear higher than the other?
• Do dress pants need to be hemmed differently on each side? Do skirts fall unevenly?
• Has a podiatrist suggested orthotics?
• Has a massage therapist commented that muscles are tighter on one side?
• Do you refrain from one-side-dominant activities (golf, softball, etc.)?
• Turn a well-worn pair of hard-soled shoes upside-down; is one shoe more worn than the other? (Usually the long leg erodes more.)

LLD Evaluation

Evaluation of LLD with a patient supine, using tape measurements from the ASIS to the malleoli, results in inter-examiner reliability only to 5 mm.⁴ Valid evaluation requires a weight-bearing A-P X-ray with the CR through the femur heads, and is as reliable as other more expensive and radiation intensive testing such as bone scans and 3-D imaging.⁵

Gait and foot analysis is critical with associated foot and ankle pain, as some conditions will significantly impact leg length. Excessive pronation can lower the pelvis and hip on that side and contribute to the appearance of a short leg, yet relying on orthotics to correct an LLD is seldom appropriate. Nike conducted an excellent study years ago to determine the best running shoe. The results were published, but not used as marketing material. The best shoe includes the least amount of padding.⁶ The incidence of ankle sprains is increased exponentially with the support of a "good" running shoe and the same is true for orthotics.⁷

If you don't perceive a stick underfoot, your foot and body don't make necessary accommodations, and you sprain your ankle. That said, running barefoot or in Keds might be great on crushed granite, dirt or grass, but the compromise made for modern running requires some padding to protect the foot from increased loading on hard asphalt.

[pb]Both a Functional LLD and a Structural LLD?

Empirical evidence suggests that a combined functional component is typically less than 4 mm; correction can work in favor or against it. In other words, an initial 18 mm LLD, after appropriate lifting regimen and chiropractic, may result in a final prescription of 18 mm, as little as 14 mm or as much as 22 mm.

Can LLD Correct Itself?

Beyond skeletal maturity, short of a Frankenstein-ian plan to re-break and stretch out bone, true LLD is not curable. However, the fix is effective and minimally inconvenient. If the patient is within a year or two of skeletal maturity, pediatric orthopedists may inject a solution to close the growth plate of the longer leg and allow the short leg to catch, which is often curative.

Treatment Considerations

Heel lifts: In an adult, adding a non-compressive silicone heel lift in increments of 3-4 mm per week seldom creates discomfort. Were we to give a patient 20 mm of lift all at once, the abnormal compensations already made often creates pain from the rapid dramatic change. When close to balancing a patient by lifting the leg with inserts, a follow-up X-ray will assist in determining the final shoe prescription.

A heel lift is typically fine up to 7-8 mm. When higher, the entire shoe must be modified because 1) the back of the shoe is generally too short to accommodate more than 7-8 mm; and 2) a heel lift greater than 7-8 mm can lead to Achilles tendon shortening, which then creates its own panoply of problems.

Shoe modification: Typically, pedorthists (highly skilled modern cobblers with special facilities to custom-alter shoes) modify shoes according to prescription. The visually undetectable lift is often incorporated between the shoe upper and the sole surface. Many insurance companies will reimburse patients for this service.

Too many shoes? We suggest patients modify three unused pairs: exercise, daily work and dress shoes. Movable or permanent heel-only lifts for occasional shoes can be purchased. Even for an 18 mm LLD, an 8 mm lift sometimes is better than nothing.

Why Add This to Your Practice?

The tremendous upside of evaluating anatomical LLD is that it is an easily managed correction that has significant positive effects on patient quality of life, enhancing their ability to participate in the activities they love. Add LLD symptoms to your marketing materials and watch patients call the office to be evaluated. Become the chiropractor who finds what others have missed, and patients will send you more referrals and make you their go-to doctor for all their chiropractic care.

References

1. Needham R, et al. The effect of leg length discrepancy on pelvis and spine kinematics during gait. Stud Health Technol Inform, 2012;176:104-7.
2. Kiapour A, et al. Relationship between limb length discrepancy and load distribution across the sacroiliac joint - a finite element study. J Orthop Res, 2012 Oct;30(10):1577-80.
3. D'Amico M, et al. Leg length discrepancy in scoliotic patients. Stud Health Technol Inform, 2012;176:146-50.
4. Jamaluddin S, et al. Reliability and accuracy of the tape measurement method with a nearest reading of 5 mm in the assessment of leg length discrepancy. Singapore Med J, 2011 Sep;52(9):681-4.
5. McWilliams AB, et al. Assessing reproducibility for radiographic measurement of leg length inequality after total hip replacement. Hip Int, 2012 Sep-Oct;22(5):539-44.
6. Nigg BM. The role of impact forces and foot pronation: a new paradigm. Clin J Sport Med, 2001 Jan;11(1):2-9.
7. Bramble DM, Lieberman DE. Endurance running and the evolution of Homo. Nature, 2004 Nov 18;432(7015):345-52.