Limb Length Discrepancy Analysis

Limb length discrepancy

A limb length discrepancy (LLD) can manifest in many variations and can result in numerous injuries ranging from lower back pain, knee/hip osteoarthritis, stress fractures, abnormal transmission of forces and increased running related injuries(Defrin, Ben Benyamin, Aldubi, & Pick, 2005; Golightly, Allen, Helmick, Renner, & Jordan, 2009; Kendall, Bird, & Azari, 2014). The exact prevalence of LLD is unknown, as estimates vary between 65% and 90% (Kendall et al., 2014) of the general population, but it is generally understood that a LLD greater than 9mm is required to cause sufficient structural or postural changes to result in injury (Defrin et al., 2005; Gurney, 2002; Kendall et al., 2014) Although there is disagreement

Structural limb length discrepancy (SLLD) is characterized by a fixed osseous malformation, while a functional limb length discrepancy (FLLD) is an asymmetry without an osseous malformation (Gurney, 2002; Kendall et al., 2014). Unfortunately, distinguishing between these two deformities is not always easy as in many cases they will occur together. Mrs. Snow’s case is a good example of SLLD and FLLD presenting together - Her anatomically longer right leg functionally shortens by excessive genu valgum, pronation of the STJ, and hip hiking during gait. Her shorter left leg functionally lengthens by hyperextending the knee, lack of pronation of the STJ, and excessive external rotation and flexion of the hip. Her legs appear to be the same length, but it is evident that abnormalities reside, as she has asymmetrical posture and

The restoration of ideal position pairs with Root theory, while achieving coordinated muscle activity pairs with the Tissue Stress Theory The root theory is built around achieving a predetermined neutral STJ position (described as neither in pronation, nor in supination), along with other ideal parameters. The Root theory explains that any deviation from the ideal criteria of foot position will result in the presence of a pathology and reduce gait efficiently (Ball & Afheldt, 2002, Daniel & Colda 2012). In Mrs. Snow’s case, the restoration of the – supinated left STJ, pronated right STJ, excessive rearfoot varus (left and right), and forefoot abduction of the right foot would be addressed. An orthotic would feature a deep heel cup to restore neutral heel position, possible postings if a Tissue Stress theory focuses on kinetic assessment of gait as opposed to the kinematic assessment. In other words, rather then reestablish the ideal parameters of pronation, the reduction of pronation speed is determined more important. Also, changing the strength and orientation of the forces acting on the musculoskeletal system is vital to restoring normal function (Ball & Afheldt, 2002, Daniel & Colda