Platelet-rich Plasma, Corticosteroid, or Lidocaine for Acromioclavicular Joint Pain

This study will compare three different treatment injections for the management of acromioclavicular joint dysfunction (ACJ Dysfunction). Patients that consent and enroll will be randomized to receive (1) a corticosteroid injection, (2) an injection of Platelet Rich Plasma, or (3) a Lidocaine injection. Follow-up will occur over a 1 year period.

Subjects with a diagnosis of AC joint dysfunction will be recruited through the primary care and orthopaedic clinics at participating hospitals and clinics. Patients that consent and enroll will be randomized to receive (1) a corticosteroid injection, (2) an injection of Platelet Rich Plasma, or (3) a Lidocaine injection. The primary outcome will be the change in PROMIS Physical Function Scale at 6 months post-enrollment. Secondary outcomes will include additional time points (viz, 1, 2, 3, 4, 5, and 12 months post-enrollment) and additional metrics (eg, AUC) as well as the PROMIS Pain Interference, Patient Acceptable Symptom State, Global Rating of Change, total limited duty days, and perceived recovery. Since the sample size is too small to establish non-inferiority by traditional hypothesis testing, a fully Bayesian approach will be used.

Eligibility Criteria:
Inclusion Criteria:

* TRICARE eligible beneficiaries (active duty, dependents, and military retired) with a primary complaint of AC joint pain.
* Age 18-65 years
* Able to speak and read English well enough to provide informed consent, follow study instructions and independently answer the questionnaires/surveys.
* Tender to palpation over the AC joint that reproduces the specific pain they are seeking care for
* Provocative test (cross-arm test, pain with push-ups, etc) that reproduces the specific pain they are here to seek care for

Exclusion Criteria:

* In the last year, the subject received any invasive interventions including injections (corticosteroid, hyaluronic acid, lidocaine, PRP, etc.) or surgery for the affected shoulder - specifically to the AC joint.
* Anyone separating from the military within 10 months (other than normal military retirement), pending a medical evaluation board, discharge from the military for medical reasons, or pending or undergoing any litigation for an injury
* AC Joint separation that are with a severity of Grades III-VI (in most cases, these are treated surgically, although 78% of military surgeons recommended preferring conservative care for Grade III separations, and 86% recommending at least 3 months of conservative care before surgical consideration.
* Systemic Disease that could otherwise be responsible for the shoulder pain (i.e. rheumatoid arthritis, gout, or psoriatic arthritis), non-musculoskeletal conditions causing shoulder pain, personal history of neoplasm, current or recent shoulder joint infection, acute fracture or dislocation of the shoulder related to the current episode of pain, or other more likely primary musculoskeletal shoulder disorders (rotator cuff pathology, bicipital tendonitis, etc.)
* Concurrent adhesive capsulitis of the affected shoulder
* History of intolerance or allergy to corticosteroids