Total Joint Replacement Educational Series Part 7: Limb Length Discrepancy After Total Hip Replacement Surgery
Addressing your questions and concerns
"I had my left hip replaced a month ago and everything is going well except that I feel off-balance, like my left is now longer than my right."
"My Physical Therapist told me that the leg that was operated on is longer than the other. What am I supposed to do about that?"
"Now that my right hip has been replaced, I use a lift in the heel of my left shoe to balance out my legs. My doctor prescribed the lift for me to make me more comfortable."
A common concern that patients have after total hip replacement surgery is a feeling that their legs are different lengths. This is called limb length discrepancy (LLD). The following information will explain the different types of LLD, possible explanations for its occurrence, and treatment options for patients who are uncomfortable with a LLD.
The Different Types of LLD
Apparent LLD: Some people have an "apparent" LLD which may make the affected leg seem longer than the other leg. There are several factors that can contribute to this feeling. Most commonly, contractures or shortening of the muscles surrounding the hip joint and pelvis make the involved leg feel longer even when they are really the same length. Also, contractures of the muscles around the lower back from spinal disorders (i.e. arthritis, spinal stenosis), curvatures of the spine from scoliosis, and deformities of the knee or ankle joint can make one leg seem longer or shorter. In the general public, some people have an "apparent LLD" as long as one half inch but usually don't notice it because the LLD occurs over time.
True LLD: A "true" LLD is where one leg is actually longer than the other. Patients can have unequal leg lengths of ¼ inch to ½ inch and never feel it too!
Combined LLD:
You can also have combinations of "true" and "apparent" LLD's.
Adjusting Leg Lengths in Surgery
During total hip replacement surgery, the surgeon may "lengthen" the involved leg by stretching the muscles and ligaments that were contracted, as well as by restoring the joint space that had become narrowed from the arthritis. This is usually a necessary part of the surgery because it also provides stability to the new hip joint. Your surgeon takes measurements of your leg lengths on x-ray prior to surgery. Your surgeon always aims for equal leg lengths if at all possible and measures the length of your legs before and during surgery in order to achieve this goal. Occasionally, surgeons may need to lengthen the operable leg to help improve stability and prevent dislocations as well improve the muscle function around the hip.
Right after your surgery it may feel like the leg that has been operated on is longer. One reason is that as opposed to the months to years that it took for your leg to shorten and muscles to become contracted, your surgeon has "lengthened" them in a very short period of time. It may take time, but your muscles usually readjust to their new position. Usually, it takes between 8 to 12 weeks for you to feel re-balanced.
Important: You must also understand that leg lengths and the potential for dislocations after surgery go hand in hand. Ideally, surgeons always aim for equal leg lengths and a very stable hip. However, at times, because of findings during your surgery, the surgeon may elect to make the operative leg a bit longer in order to tighten up the joint and prevent a possible dislocation. Small differences in LLD are usually well tolerated by patients given time. However, it is most important to understand that it's better from your perspective to have a slightly longer leg if necessary to prevent dislocations rather than a hip that is at risk for dislocating.
Treatment Options for Feeling "Off-Balance" after Hip Surgery
Most of the time, patients never feel this difference and therefore no treatment is needed. As previously stated, it may take a few months for your muscles to readjust. In the early months after surgery, interventions like stretching and strengthening exercises may actually speed the natural course of re-balancing. Factors that will influence whether you continue to feel the difference include arthritis of the opposite hip, spinal muscle contractures, scoliosis, and deformities or stiffness of the ankle and knee joints.
When patients continue to notice symptoms of LLD, treatment usually consists of inserting a "lift" into the shoe of the shorter leg. In some patients, one or two of the simple over the counter Dr. Scholl's-type heel inserts can be enough. Occasionally, patients may need a thicker insert. The goal of treatment and size of the insert is always based on how you feel and we recommend that you use the standing blocks as the best way to measure what makes you feel you feel balanced, rather than tape measures or x-rays.
We hope this information has been useful to you. If you have questions about LLD after surgery, please don't hesitate to ask your surgeon or assistant.
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On September 14, 2007 I had a right THR at King's College Hospital in London. I had previously had left THR and both knees TKR. (Also right ankle arthrodesis over a period of 7 years.) I have been left with an actual lld of 1". Apparently I have some pelvic tilt. I cannot walk properly since the procedure, even with a raised shoe. I'd like to know what is the percentage occurence of this outcome, which in my case has resulted in effectively crippling me.
I am a PT in USA. I have seen LLD many times. Many patients get upset too. Few have gone through revisions and few will live the way it is. It is sad but if there is an exisiting pelvic obliquity it is impossible to correct it till a PT works on stretching your muscles around the hip and on the good side.
While the various reasons for leg length discrepancy are listed in the text, the most important concept is that whether a patient has a true, apparent or a combination of both, the lift size is based on feel.
If you feel balanced using a one-inch heel lift, then this is what is important compared to an actual measurement. If the size of the heel lift is too large to fit in the shoe then some patients choose to have the lift built on the outside of the shoe.
Because you have a pelvic obliquity, it can be beneficial to try physical therapy to help stretch the muscles of the hip. After it has been a year since the hip replacement, however, physical therapy is not likely to drastically decrease the LLD.
Because LLDs are often attributed to multiple factors, it is hard to discern whether having a revision surgery would even help the problem. This is why revision surgery is rarely recommended or medically indicated for the correction of a LLD. Revision surgeries for the treatment of leg length discrepancy have a significant risk of instability, which could result in recurrent dislocations.
With any problem or pain after a surgery, one of the best things a patient can do is to obtain a second opinion from an orthopaedic surgeon who specializes in total joint replacement surgery. Most of the time revision surgery will not be recommended, but at least you will have a better idea of what is causing the LLD.
While there is no statistic for the frequency of LLDs, it is a common occurrence due to all of the factors that can be involved. Before our patients undergo a total hip replacement, they are thoroughly educated about LLDs, including treatment post-operatively. We also try to identify patients who are at increased risk for LLDs due to arthritis of the spine, a pelvic obliquity or hip arthritis on the non-operative side. While there is no way to eliminate the possibility of a LLD, preoperative education ensures that a patient can make an informed decision when deciding whether to undergo total hip replacement surgery.