Effect of Hip Versus Spinal Joint Mobilization on Hip Muscle Strength
Condition: Joint; Derangement, Knee
Study type: Interventional

Summary: 
      Patients with painful knee conditions often present with hip muscle weakness. This weakness
      can lead to, and perpetuate, knee problems. Diminished strength causes movement impairments
      that can lead to pathology, functional limitations and disablement. In some cases, this hip
      muscle weakness is not caused by simple disuse and muscle shrinkage (atrophy). Hip weakness
      may be caused by an inhibitory mechanism that limits the force output of a muscle. The
      inhibition is reflexive and is in response to pain or joint dysfunction. Joint
      mobilization/manipulation can quickly reduce pain and improve joint function, possibly
      decreasing inhibition and increasing strength. Joint mobilization/manipulation may facilitate
      strength recovery. By restoring strength sooner, the patient may avoid the deleterious
      effects of prolonged muscle weakness and achieve quicker or better outcomes.
    

Detailed description: 
      Patients with knee pain often present with hip muscle weakness. Hip muscle weakness can cause
      faulty hip mechanics that contribute to adverse knee joint kinematics. The gluteus maximus is
      the largest hip muscle and its primary actions are extension and external rotation of the hip
      joint. Gluteus muscle weakness was associated with varied knee injuries, including
      patellofemoral pain syndrome, iliotibial band syndrome and anterior cruciate ligament (ACL)
      sprains. In 2 systematic reviews that have assessed subjects with anterior knee pain, the
      authors found strong evidence for impaired hip extensor muscle strength and activation. In a
      prospective cohort study, weak hip external rotation strength was associated with the
      development of anterior knee pain and the hip strength further diminished after pain started.
      There is evidence supporting gluteal muscle strengthening for the management of anterior knee
      pain. Some authors argue that gluteal muscle weakness may be caused by muscle inhibition and
      not simple disuse atrophy. This reflexive muscle inhibition is neural-mediated and driven by
      pain or joint dysfunction. Joint mobilization/manipulation reduces pain and improves joint
      function and may help maximize strength by reducing inhibition. Yerys et. al. (2002)
      demonstrated that hip joint mobilization caused an immediate 14% increase gluteus maximus
      strength and Makofsky (2007) found an immediate 17% increase in gluteus medius strength after
      hip joint mobilization. Both of these studies, however, used asymptomatic subjects and their
      results may not translate to symptomatic patients. Chilibeck (2011) found an immediate 14%
      increase in hip extension strength, and 12% in hip abduction, after lumbar spine thrust joint
      manipulation. This study also used an asymptomatic sample. In addition, thrust joint
      manipulation is used less frequently in physical therapy practice compared to nonthrust joint
      mobilization. The scientific objective for this research is to assess the effect of spine and
      hip joint mobilization on hip muscle strength in patients with knee pain.

      The study aims to answers the following questions:

        1. Does hip joint mobilization immediately improve hip muscle strength in patients with
           knee pain?

        2. Does spinal joint mobilization immediately improve hip muscle strength in patients with
           knee pain?

        3. Does hip or spinal joint mobilization create a greater improvement on hip muscle
           strength in patients with knee pain?

      This pilot, prospective clinical trial will use a randomized clinical trial design. The
      primary dependent variable is isometric muscle strength, measured in pounds, an interval
      level of measurement. Muscle strength will be determined by the maximum voluntary contraction
      (MVC) and measured by an electronic hand-held dynamometer. Hand-held dynamometric muscle
      testing has demonstrated good intrarater reliability and validity when compared to Biodex
      dynamometry. Although there is no established minimal clinically important change (MCID)
      score for strength testing, some authors have suggested a 10% change in strength to be
      clinically significant. Pain will be measured at the ordinal level with the numeric pain
      rating scale (NRPS). Investigators will recruit subjects from routine clinical practice
      within the NYULMC-CMC. The outcomes variables (isometric muscle strength and strength) will
      be measured before and after the intervention at the initial evaluation visit. After these
      measures are obtained, the participation in the study is complete. There is no follow-up.
    

Intervention name(s): Joint mobilization
Intervention type(s): Other
Intervention description(s): Mobilization and manipulation are manual therapy techniques" comprising a continuum of skilled passive movements to the joints and/or related soft tissues that are applied at varying speeds and amplitudes, including a small-amplitude/high- velocity therapeutic movement."16 The term joint mobilization, or nonthrust mobilization, often refers to slow, "rhythmic, repetitive passive movements to the patients' tolerance, in voluntary and/or accessory range and graded according to examination findings."
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment