Manual Therapy to Treat Gluteus Medius Trigger Points

People with anterior knee pain have significant hip abductor muscle weakness compared to
healthy people (Prins, 2009). Hip abductor weakness has a strong correlation with impaired
lower extremity mechanics and increased pain with functional activity (Stickler et al. 2014).
A study by Roach et al in 2013 found that 97% of patients with anterior knee pain had a
trigger point in their gluteus medius muscle, while only 23% of healthy controls had trigger
points. Trigger points alter normal muscle activity and increase pain in patients (Lucas,
2010, Ibarra et al 2011). Hip abduction strengthening has been found to significantly
decrease pain and improve function in patients with anterior knee pain (Earl, 2011). By
decreasing trigger points in the gluteus medius the investigators may be able to increase hip
abduction strength reducing pain and dysfunction in patients with anterior knee pain.

Both Dry Needling (DN) and Soft Tissue Mobilization (STM) are manual therapy interventions
commonly used by physical therapist to decrease trigger points in muscles. Currently, no
research has examined the effectiveness of manual therapy to treat trigger points and improve
hip abductor strength in patients with anterior knee pain. Clinically, the investigators have
noted that after a patient has been treated with STM or DN that the investigators see
immediate improvements in hip abduction strength. The investigators do not know if noted
improvements result from repeated strength testing practice or actual improved firing
strength of muscles.

The primary objective of this study is to see if manual therapy to the gluteus medius can
significantly alter within-session measurements of hip abductor strength in patients with
anterior knee pain.

The secondary objective of this study is to see if manual therapy to the gluteus medius can
significantly alter within session pain in patients with anterior knee pain.

Patients referred to our physical therapy clinic for anterior knee pain will be considered
for this study. After explaining the study and answering any patient or parent questions,
informed consent will be obtained for those individuals wishing to participate. The
participants will be screened to see if they meet the inclusion criteria, and will be
randomly to a treatment group (Dry Needling, Soft Tissue Mobilization, Placebo control). This
will be a single blinded research study with the assessor being blinded to the intervention.
The therapist who performs the hip abductor strength measurements will not be the same
therapist who performs the experimental interventions. The patient cannot be blinded to the
treatment that they receive. The therapist performing the intervention will open a sealed
envelope that allocates patient to Dry Needling, Soft Tissue Mobilization, or Sham Needling
group. Following the experimental intervention all patients will perform the same hip and
core exercise protocol.

Pre-treatment evaluation measures will be taken on the patient blinded assessor.

These will consist of:

- Hand held dynamometer hip abduction strength measurements.

- Pain with single leg squat

The subject will then receive the appropriate treatment based on his/her random assignment to
experimental treatment groups by the treating therapist.

Post-treatment evaluation measures will be taken on all patients by the blinded assessor
immediately following treatment. These will be the same measures taken pre-treatment.

- Hand held dynamometer hip abduction strength measurements.

- Pain with single leg squat Patients will then perform the same hip and core exercise
protocol, Following these exercises Post-Exercise evaluation measures by the blinded
assessor. These will be the same measures taken pre-treatment.

Inclusion Criteria:

- Acute anterior knee pain of <90days

- Ipsilateral hip abductor weakness of >15%

- 2/10 pain with single leg squat

Exclusion Criteria:

- Contraindication to dry needling or soft tissue mobilization

- Non-mechanical anterior knee pain

- Fear of needles