What are long term complications of mild to moderate leg length discrepancy?

Question

A leg-length discrepancy (from femur fracture or any other etiology) obviously causes an imbalance in gait, and therefore the entire kinetic chain. This often happens at a young age and therefore they face an entire lifetime of gait imbalance.

A large discrepancy is sometimes treated surgically (but it is not a minor procedure). Moderate, with a shoe lift. Mild, with an insole. But when not wearing a lift or insole (e.g. walking barefoot at home), your kinetic chain is still imbalanced.

Which leads me to ask:

• What are the long term MSK complications resulting from this imbalance?
• Are there physical therapy techniques that aid in minimizing harm to joints etc?

(This was an interesting case in my ortho rotation; I was not satisfied with the answers from 2 orthopedic surgeon attendings, who refer to orthotics but don't regularly refer to PT for this. My reading has yielded mixed opinions.)

Answer 1

Two Types of Leg Length Discrepancies (LLD)

Just a heads up it's pretty tough to give a general answer to such an involved area (I tried lol). I’m forced to leave quite a bit out as there are so many causes, tests, treatments etc.

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True LLD

• Simply put there is an anatomical or structural difference (L) vs (R)
• Typically these are congenital (i.e malformations such as adolescence coxa vara) or trauma (such as a fracture can also cause this)
• Exactly you’ve already outlined above. as this is an actually difference in length some type of external intervention is required.
• Unfortunately when dealing with a True LLD anytime the brace, orthotic etc. is removed the underlying kinematic imbalance will reappear.
• Not surprisingly you’ll see frontal plane devations toward the affected (shorter) side - such as a lateral pelvic tilt, scoliosis etc..

Functional LLD

• An apparent or functional LLD generally results from a compensation due to improper positioning -- they are never structural.
• There’s a whole battery of orthopedic tests used to narrow down the cause and type of LLD, I will not be going into this in any depth. Also there are TONS of conditions that can lead to this, for simplicity I’m going to focus primarily on Sacroiliac (SI) Joint and the related musculature.

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SacroIliac Joint Dysfunction

Pain in or around region of joint that is presumed to be due to malalignment or abnormal movement of SI joints

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Common Pelvic Girdle (SI) Dysfunctions

• Posterior torsion of innominate
• Anterior torsion of innominate
• Superior Pubis
• Innominate Upslip
• Innominate Outflares

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Sacroiliac Joint - 3 Kinetic Chains

• LE kinetic chain
  • Sacrum-innominate-LE
• Spine kinematic chain
  • L4-5-sacrum
• Closed kinetic chain
  • Innominate-sacrum-innominate

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Symmetrical Motion

• Movement of both in nominates relative to sacrum
  • See this primarily with ant and post pelvic tilts

• Asymmetrical motion

  • Antagonistic motions of each innominate relative to sacrum

• Lumbopelvic motion

  • Rotation of Spine & both innominates around femoral heads
• Posterior torsion
  • Ipsilateral ASIS higher
  • Ipsilateral PSIS lower

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SI Joint: Supportive Network of Musculature

• Iliopaoas
• Rectus Femoris
• Hip abductors/adductors
• Piriformis
• Gluteus maximus
• Sartorius
• Hamstrings
• Abdominals
• Quadratus Femoris
• Multifidus

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Joint Characteristics

• Primary support to SI jt - self locking mechanism, shape of the articular surfaces, and the ligaments

• SI Joint – Normally in a position of stable equilibrium and b/c of that there tends to be the need for significant force to disrupt it

• some of the strongest muscles in the body surround the SI but none have the primary function of moving it

• no voluntary SI movements and the movements that we do see is influenced by other body regions thru weight changes and positional changes -these surrounding muscles are going to facilitate the stability of the joint

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Musculature Details

Iliopsoas - Unilateral - when the pelvis and femur are fixed the iliopsoas will produce ipsilateral FB of the lumbar spine with contralateral RO. The FB of the spine relative to the pelvis will decrease lumbar lordosis Bilateral contraction of iliopsoas produces ant pelvic rotation and takes the sacrum along

Rectus Femoris - when pelvis is fixed, flexes the thigh on the pelvis - thigh and lumbar spine are fixed – and pelvis is free to move – it can cause ant innominate torsion ipsilaterally

Hip Abductors / Adductors - Directly influence SI jt thru the pubic symphysis - since the gluteus medius tends to pull the ilium away from the sacrum- almost a distraction effect - Create stress through public symphyisis - Adductors- create stress thru pubic symphysis - Abductors sartorius may have an anterior torsion effect on the innominate when the hip is extended and the knee is slightly flexed abductor

Piriformis: -Bilateral contraction of the piriformis produces a nutation effect on the sacrum – Unilaterally get a rotational effect toward contralateral side

Gluteus Maximus: Bilateral contraction of the maximus- post pelvic rotation – unilateral contraction – causes ipsilateral post torsion

Hamstrings: Tightness can cause post innominate torsion

Transversus Abdominis: Contributes to the stiffness of the SI jt

Quadratus Femoris - bilaterally contraction-stabilizes the lumbar spine and can result in sacral nutation

Multifidus – it is considered an anticipatory stabilizer of the LS spine the multifidi are recruited as a stabilizer before the Lower and Upper limbs move Co contraction of multifidus and the TrA – further increase stiffness of the SI jt. Ipsilateral side bending will increase the shearing stress to the ipsilateral SI jt

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Specific Treatments

As treatments are very evaluation dependent I’d really need results of an evaluation and orthopedic testing otherwise I’d just be throwing out random exercises.

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Sources

1. Orthopedic Clinical Examination: An Evidence Based Approach for Physical Therapists.

2. A System of Orthopaedic Medicine, 3rd Edition.