The Indirect Method for Determining Leg Length Inequality

April 9th, 2008
  1. Patient should be in an open backed gown and lower clothing loosened in order to view the spine, sacral dimples, iliac crests, shoulder level, and head tilt.
  2. Have the patient stand with their back to you, and their bare feet 8 inches apart.
  3. Place hands on top of iliac crests to help visualize unleveling. Determine if there is any unleveling of the sacral dimples. Place hands on the Greater Trochanters to determine any unleveling. Determine if there is a spinal curvature, shoulder tilt, or head tilt.
  4. If you have observed unleveling of the iliac crest, greater trochanters, or sacral dimples, have the patient fully suppinate both feet. If the greater trochanters, iliac crests, and sacral dimples are restored to level, then the leg length inequality if determined to be functional. If fully suppinating the feet does not correct the unleveling then the leg length inequality is determined to be structural.
  5. If structural leg deficiency has been determined then place about 2 layers of the Leg Inequality Measurement Pad under the foot of the low iliac crest.
  6. Recheck as in item #3.
  7. If some unleveling persists, continue adding or reducing layers of the Leg Inequality Measurement Pad under foot until you are satisfied with the iliac crest, greater trochanter, and sacral dimple level.
  8. Count the number of layers under foot and multiply by 3 mm. The result will be a very close estimate of structural leg deficiency, and the total amount of heel lift, foot lift or combination foot/heel lift required.
  9. If you note severe pelvic asymmetry, then a radiograph of the lumbar spine, pelvis, and femur heads is recommended. View How to Determine Whether a Heel Lift is needed.

Leg Length Inequality Following Total Hip Replacement

March 27th, 2008

Management of Leg Length Inequality following Total Hip Arthroplasty

Total Hip Arthroplasty (THA) or Total Hip Replacement (THR) was introduced in the 1960’s, and was considered the “operation of the century”, because it revolutionized the management of elderly patients who were crippled with arthritis of the hip joints.1 Patients who suffered from hip fractures, or osteonecrosis of the femoral head have also benefited. Through the past 40 plus years many advancements in the technology of the hip prosthesis, pre-operative and intra-operative measurement techniques, and surgical procedures have resulted in much better outcomes in regard to hospital stays, better range of motion, improved gait, and durability of the prosthesis itself.

The major goal in total hip arthroplasty is to restore the biomechanics of the hip and minimize leg length inequality (LLI).

Leg length inequality is a common occurrence2 as the operated hip is usually lengthened with the placement of the femoral component of the prosthesis. In the 70’s one study revealed that the average leg lengthening following total hip arthroplasty was 15.9mm in 27% of the cases studied and required heel lifts on the opposite leg to help correct the problem.3 Another study revealed that revision hip surgery was required for symptomatic limb length discrepancy. The mean limb-length discrepancy at the time of the revision was 4 cm (range, 2 to 7 cm).4 4 cm being the equivalent to approximately a little over 1.5 inches. Studies have been done which reveal that 5mm of leg deficiency is significant and can cause low back and other related symptoms.5 Another point that needs to be considered is that some patients have leg deficiency, acquired or congenital, prior to hip arthroplasty, and the surgery can either aggravate or ameliorate this discrepancy.

Why does leg lengthening occur during this type of procedure?

In the literature, we find an emphasis on developing a systematic and reproducible approach to pre-operatively evaluating patients for leg length discrepancy before undergoing THA. A pre-operative x-ray will establish any pre-existing leg deficiency. Then an operative plan can established, but intra-operative evaluation must also be done based upon the components available and the final components after being implanted. Intraoperative objective measurement of limb length is critical to avoid over-lengthening. The surgeon has at his/her disposal several hip prosthesis to choose from during surgery based upon what conditions he/she finds during the procedure. For instance, the patient may need a certain type of shaft to improve stability because of the condition of the femur. Even with all the pre-examination, with x-rays, CT’s or MRI’s, the final decision on the size and type of prosthesis comes when the surgeon can actually view what he/she has to work with.

Techniques are being developed in digital templating and image guided surgery that may provide better accuracy and improved outcomes concerning LLI, but for now what is needed to keep leg length inequality minimal, is a good pre-operative plan, attention to detail, intra-operative measurements referencing the well leg after the components are implanted, and then post-operative measurements some weeks following the surgery. Even with those measures there will be cases of significant leg length inequality, but the post-op measurement will discern the amount, and simple procedures such as the addition of shoe lifts or heel lifts can reduce or eliminate LLI before related problems occur.

What are some of the problems that occur with leg deficiency following THA?

Some of the problems that occur are a limp, leg pain, hip and/or back pain, hip joint instability, paraesthesia in the lower extremity, disc problems, osteoarthritis of the knee, poor oxygen consumption while walking, and vertigo due to alteration of the postural control system.6, 7, 8, 9, 10, 11, 12
What can be done to help remedy the problem should it occur?

Post-operatively a standing x-ray should be taken with the heels 8 inches apart and the knees extended. The primary ray should be at the level of the umbilicus and collimated to 14 X 17 inches. This film will reveal any leg deficiency, pelvic deficiency, sacral deficiency, or L5 deficiency.

standinga-p.jpg

More on Why, When, and How to Determine Whether You Should Use Heel Lifts - for clinical advice on diagnosing and measuring leg length discrepancy. Also, indirect examination using a calibrated foot support can be useful. If the measured deficiency is 2 cm or less a heel lift or shoe lift will certainly reduce if not eliminate the problem.

Should the deficiency be greater that 2 cm. and problems severe, further consultation with the orthopedist should be considered to assess other options.

Citations

1 Learmonth ID, Young C, Rorabeck C “The operation of the century: total hip replacement” Lancet. 2007 Oct 27;370(9597):1508-19

2 Maloney WJ, Keeney JA. “Leg length discrepancy after total hip arthroplasty” J. Arthroplasty. 2004 Jun;19(4 Suppl 1):108-10.

3 Williamson JA, Reckling FW, “Limb length discrepancy and related problems following total hip joint replacement” Clin Orthop 1978 Jul;134:135-138

4 Parvizi J, Sharkey PF, Bissett GA, Rothman RH, Hozack WJ “Surgical treatment of limb-length discrepancy following total hip arthroplasty” J Bone Joint Surg Am. 2003 Dec;85-A(12):2310-7.

5 Friberg O, “Clinical Symptoms and Biomechanics of Lumbar Spine and Hip Joint in Leg Length Inequality” Spine. Vol 8 Number 6 Pages 643-649

6 Austin MS, Hozack WJ, Sharkey PF, Rothman RH, “Stability and leg length equality in total hip arthroplasty” J Arthroplasty. 2003 Apr;18(3 Suppl 1):88-90.

7 Friberg O, “Clinical symptoms and biomechanics of lumbar spine and hip joint in leg length inequality” Spine. 1983 Sep;8(6):643-51.

8 ten Brinke A, van der Aa HE, van der Palen J, Oosterveld F, “Is leg length discrepancy associated with the side of radiating pain in patients with a lumbar herniated disc?” Spine 1999 Apr 1;24(7):684-6

9 Golightly YM, Allen KD, Renner JB, Helmick CG, Salazar A, Jordan JM “Relationship of limb length inequality with radiographic knee and hip osteoarthritis” Osteoarthritis Cartilage. 2007 Jul;15(7):824-9. Epub 2007 Feb 22

10 Williamson JA, Reckling FW, “Limb length discrepancy and related problems following total hip joint replacement” Clin Orthop 1978 Jul;134:135-138

11 Irvin RE. “The origin and relief of common pain” J Back Musculoskeletal Rehabil. 1998;11(2):89-130

12 Gurney B. “Leg length discrepancy” Gait Posture. 2002 Apr;15 (2):195-206.

Introduction and Purpose

March 13th, 2007

Art Gross, D.C.

The purpose of this Blog is to provide information concerning the effects of leg length deficiency and bone abnormalities on the biomechanics of the human body. There is a wealth of information concerning this subject, and it is my hope to bring that information out of the deep recesses of where it exists. We will be posting research summaries, articles, and commentary on topics we feel are timely and of importance. And we also will provide links to those topics so you can read the article or abstract and form your own opinion.

From time to time I may give you my view based on 39 years of practice and the intense interest I have on the mechanical effects of heel lifts, and heel wedges. It won’t be on philosophy, and it won’t be on technique. It will be on what seemed to help, and what didn’t.

Hopefully you’ll be exposed to things you weren’t aware of that can benefit patients or clients who are seeking help.

Our products, advice on using them, and links to information about shoe lifts elsewhere, can be found at G/W Heel Lift.

Art Gross, D.C.

Evaluating and Treating Leg Length Discrepancy

March 13th, 2007

Leg Length DeficiencyAn interesting article in Podiatry Management in September of 2006; a CME module, entitled “Evaluating and Treating Leg Length Discrepancy“.

Dr. Caselli makes several good points concerning structural limb length discrepancy and how to evaluate it, but there are a few points in which I would like to comment further.

He states that structural limb length discrepancy is present in 6 to 12 percent of the athletes that present with apparent leg deficiency, and that functional leg deficiencies are more common. In my experience, not only with athletes, but patients in general, structural leg deficiency was more prevalent than functional leg deficiency. Especially, patients with chronic back pain.

The article also discusses the direct and indirect methods of measuring leg deficiency. The consensus of many writers and researchers is the direct method is prone to error, is difficult to duplicate, and inter-examiner reliability is poor. In my opinion why do we even discuss it further? If it isn’t a valid test then it shouldn’t be taught in the schools any longer.

Dr. Caselli also states that a CT scan is the most accurate method of determining structural leg length. That is true, but it is not necessary in the majority of cases. After examination and ruling out a functional leg deficiency. A simple A to P standing x-ray, which includes the femur heads, the pelvis, and the 5 lumbar vertebrae, will give you a wealth of information as to the possible cause of the patients back pain problem. It will show you the amount of leg deficiency, pelvic unleveling, sacral unleveling, 5th lumbar unleveling, and the spinal angle. You should think of it as a blue print to help with restructuring.

The CT scan should be the next image of choice, following the plain A to P lumbo-pelvic (postural view), for those patients with extreme leg deficiencies of 2cm or more, and when it is necessary to determine if the deficiency is coming from the femur, or tibia and fibula.

If you have time, have a look at this article concerning the evaluation and treatment of leg length inequality. It may give you a few more tips on the evaluation of leg deficiency and its relationship with chronic back pain patients.

The content of this Blog is designed primarily for use by qualified physicians and healthcare providers. The information contained herein should not be used as a substitute for the advice of an appropriately qualified and licensed physician or other healthcare provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Heel lifts should always be used after evaluation and prescription by a qualified health care professional.

Design of Cork and Injection Molded Heel Lifts

March 13th, 2007

Cork Heel Lifts

With this blog just beginning, I feel it might be important for the readers to get a better understanding of why our heel lifts are designed the way they are.

Thirty years ago when we started manufacturing our own injection molded heel lifts, we knew that about 25% of the height of the lift was lost if the measurement was taken from the back of the heel, since the inferior part of the calcaneus strikes the heel of the shoe approximately in the center of the radius of the heel counter, not at the back of the heel counter.

That is to say, the weight of the body is supported the approximate center of the heel-bone. In other words, if you have a tapered heel lift that is marked 9mm as its size, which measures 9mm at the very rearmost edge of the lift, you are only receiving about 75% of the effective height of the heel lift.

An article published in The Foot, September 2006, verified this concept. By using other vendors’ heel lifts measured at the most posterior part of the lift, they found that the actual amount of elevation increase was only 76.4%. of the nominal height.

Grey foot diagram

Design of Cork Heel Lifts

Forty years ago the beveled cork heel lift was born. We felt that a slight bevel around the edge of the lift would be better because it would allow the lift to lie flat in the shoe and not attempt to curl up around the edge. Remember, the majority of shoes at that time did not allow you to lift the insole to slide a shoe pad or heel lift under it, much less remove the insole and replace it with a more comfortable one. Shoe components were glued and sewn together at that time.

Our cork lifts have an area at the advertised height at the center radius of the lift, then taper smoothly down into the arch of the foot, making a smooth indetectable transition underfoot.

A Cork Heel Lift from G&W

Dense cork is an excellent material for in-shoe lifts. It is lightweight, and compresses very little. (Our tests reveal less than 1mm compression after a year of constant use). Our cork lifts have a smooth vinyl top covering to protect them from abrasion and prolong their life. Cork lifts are a particularly good alternative for fashion or dress shoes, due to their light weight, and the ability to put them on the top of the insole of the shoe. Also, the cork is just soft enough to feel a little better than other types of lifts when placed on top of the insole directly underfoot.

Cork lifts are not as durable as injection molded lifts, but when used in dress shoes, or permanently placed in a shoe, they really don’t have to be. The need for durability is only an issue if you are going to be changing the lift from shoe to shoe.

Design of Injection Molded Heel Lifts

When we designed the molds for our injection molded lifts, we made them longer than had previously been practiced, tapered them back to front on a long slope, and designed the advertised height at the center of the rounded radius of the lift. By doing so, the calcaneus rests on that area and the full mechanical advantage of the lift is transferred up the leg. Hence, if the patient needs 9mm of lift to compensate for leg deficiency, they are getting 9mm in height advantage from the lift.

The long taper of the lift into the mid foot makes a smooth and comfortable transition from heel strike to toe off when standing, walking, or running.The injection molding process, compared to pouring material into an open-topped cavity mold, ensures consistent height, with no voids or defects in the lift. It also requires having as many as 25 different costly chrome-plated steel molds to produce the various width and height combinations.

We use a latex free PVC (vinyl) material with a durometer of 50-60 which results in strength, flexibility, and no compression with use. Our lifts can be easily trimmed with a razor blade, scissors, or sander if necessary.

All of our heel lifts are available in several different heights (3mm, 5mm, 7mm, 9mm, and 12mm) as well as 6 different widths in order to accommodate any shoe size.

Greater than 12mm height in an in-shoe lift is simply not realistic; the wearer will walk out of the shoe and become prone to ankle injuries due to poor stabilization in the shoe.

The content of this Blog is designed primarily for use by qualified physicians and healthcare providers. The information contained herein should not be used as a substitute for the advice of an appropriately qualified and licensed physician or other healthcare provider. The information provided here is for educational and informational purposes only. In no way should it be considered as offering medical advice. Heel lifts should always be used after evaluation and prescription by a qualified health care professional.