The purpose of this study is to evaluate and compare the short and long-term effectiveness of two common interventions, manual physical therapy versus corticosteroid injection, for the treatment of shoulder impingement syndrome.

Dysfunction in the shoulder has been reported to affect up to 33% of the general population and generate up to 5% of all consultations from general practitioners. Shoulder problems have been reported as the second highest musculoskeletal complaint for those seeking care from a physical therapist in a deployed environment. Impingement syndromes occur in nearly anyone who repeatedly or forcefully uses their upper extremity in an elevated position, which is very common in the active duty population, and is often characterized by pain during this motion. Managed improperly, this can lead to disruption in work performance and prolonged disability.

Corticosteroid and analgesic injections are some of the most common procedures for orthopedists, rheumatologists, and general practitioners to use in the management of shoulder pain. Conflicting reports from systematic reviews questions the efficacy of corticosteroid injections over other interventions, including oral non-steroidal anti-inflammatory drugs (NSAIDs). Additionally they are not without potential risk such as infection or deleterious effects of prolonged corticosteroid use to include tissue degeneration reported in animal studies as well as other regions of the human body. Manual physical therapy offers a non-invasive approach with negligible risk in as few as three to six sessions and has been shown to improve strength and function in this patient population.

The purpose of this study is to evaluate and compare the effectiveness of two interventions that are commonly used in the management of shoulder impingement syndrome.

1. Evaluate the effect that a subacromial corticosteroid injection has on a subject's function and pain as measured by the Shoulder Pain and Disability Index (SPADI).
2. Evaluate the effect that manual physical therapy has on a subject's function and pain as measured by the Shoulder Pain and Disability Index (SPADI).
3. Compare the effect sizes of the two different interventions in a patient population with shoulder impingement syndrome.

Inclusion Criteria:

• Age between 18-65
• Read, write, and speak English
• Tricare beneficiary and eligible for healthcare at a military treatment facility
• Primary complaint of shoulder pain
• Meets diagnostic criteria for shoulder impingement (mentioned below)

To be included in the study participants are required to have:

1. pain with one of the 2 tests in category I, and
2. pain with one test from either category II or category III. * "pain" is defined as reproduction of the usual pain that the subject experiences that makes up the nature of their complaint.

Category I: Impingement signs

1. Passive overpressure at full shoulder flexion with the scapula stabilized.
2. Passive internal rotation at 90 degrees of shoulder flexion in the scapular plane and in progressive degrees of horizontal adduction.

Category II: Active shoulder abduction Active shoulder abduction Category Ill: resisted break tests

1. Abduction
2. Internal rotation
3. External rotation

Exclusion Criteria:

• History of shoulder injection in last 3 months
• History of shoulder dislocation, subluxation, fracture, adhesive capsulitis of the glenohumeral joint, or cervical/shoulder/upper back surgery
• Full-thickness rotator cuff tears
• Presence of cervical radiculopathy, radiculitis, or referral from cervical spine
• Total baseline SPADI score not less than 20% (to prevent a ceiling effect with treatment)
• Prior OMPT treatment to the involved limb for the current episode of pain
• Military service members pending a medical evaluation board, a physical valuation board, or equivalent discharge process, or in medical hold to determine long term disposition. For non-military personnel, anyone that is pending or undergoing any litigation for their injury.
• Contraindication to receiving a corticosteroid injection (allergies, adverse reactions, history of multiple injections in that area even if not within last 30 days, etc)
• Inability to fill out informed consent form
• Unable to come into the clinic for regular treatment over the course of the following month.

Data sharing can only occur after a Data Sharing Agreement has been approved by the US Defense Health Agency