Past Studies
The Effect of Leg Length Discrepancy on Health-Related Quality of Life:
Is The "2 cm Rule Appropriate?"
 Introduction:
A Leg Length Discrepancy (also known as LLD) is a condition when one of the legs is longer than the other. It is not uncommon for a growing child to have a slight LLD; however, a problem should be addressed if the leg length difference is more than 2 cm. The greater the difference in leg length, the more the child must compensate their normal posture and gait.
LLD can be caused by a number of things, all of which change bone growth. A fracture on a leg, for example, can damage the cells that help bone to grow on just that leg. This results in one leg growing more than another. Other LLDs are caused by diseases of the bone. Osteomyelitis is one such example. This disease of the bone can injure the growth plate, a specific region of the bone where growth in length occurs. Tumors can also invade the growth plates causing LLD. Other LLDs are congenital. This means that one is born with legs that are of unequal length.
Only Leg Length Differences over 2cm are usually detected. Limping, irregular gaits or unequal shoe wear are all signs of LLD. A patients with a LLD less than 2cm, most likely will not need treated. In the range of a 2-6cm leg length difference, orthotics (shoe lifts), epiphyseodesis, or femoral shortening to equalize the leg lengths are all treatment options. 6-20 cm leg length differences usually require leg lengthening procedures or a combination of leg lengthening and shortening of the opposite side.
The goal of surgical equalization of leg length discrepancy (LLD) is to improve the quality of life (QOL) of affected individuals by improving function and appearance. While many surgeons utilize a cutoff point of 2cm as a treatment guide, little attention has been focused on the effect of LLD on QOL. The purpose of this study is to determine the critical cutoff size for the effect of LLD on QOL. Such information may help refine the surgical indications of leg length equalization in these patients.
Methods:
QOL and scanogram data were collected from children diagnosed with LLD at our institution. QOL was assessed using the parent short-form of the Child Health Questionnaire (CHQ). QOL scores from this group were compared to normative data. Statistical analysis was conducted to assess the relationship between size of LLD and QOL.
Results:
Our study group consists of 41 patients (50 observations) with an average LLD of 2.05cm. Compared to the normal values, the LLD patients scored significantly lower on four CHQ domains. Correlation analyses revealed a negative relationship between size of LLD and several psychosocial domains. Independent t-test revealed that children with LLD ≤ 2cm scored significantly higher in six domains than children with LLD>2cm: General Health, Parental Impact-Emotional Scale, Parental Impact-Time Scale, Family Activities, Family Cohesion, Psychosocial Summary Score.
Conclusion:
With increasing LLD, differences in psychosocial health become especially apparent. This study suggests that children with LLD>2 cm experience significant differences in QOL. Therefore, we support the use of this cutoff as a guideline for intervention.
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