The posterior antebrachial cutaneous nerve (PACN) can be compressed between the deltoid and triceps, with resultant pain and dysfunction. The active treatment for this study will be injection of the point of compression and along the painful course of the sensory nerve with 5% dextrose. The control treatment will be physical therapy.

The PACN is a purely sensory nerve that originates in the midforearm, courses anterior to the lateral epicondyle, and travels proximally until it dives between the posterior portion of the V shaped insertion of the deltoid and the external? insertion of the triceps, whereupon it joins with the radial nerve.

A proposed pathological explanation is that repetitive co-contraction produces irritation and compression of the nerve at the delto-tricipital (D-T) fascial penetration point. Clinically the patient experiences pain localized to that compression point, and traveling distally along the course of some or all of the posterior femoral cutaneous nerve.

Perineural injection of dextrose has been previously reported for therapeutic use in chronic pain associated with Achilles tendinopathy. Empirically,injection of D5W with a small needle along the course of the PACN and at the D-T penetrator has been found to resolve both pain and dysfunction (describe dysfunction).

Participants will be randomly assigned to either 1 month of physical therapy or to 0,1,2 and 3 week injection of D5W. The use of standardized measurement tools for pain (0-10 numerical rating scale) and function (Quick DASH) will be utilized to determine baseline status and status at 1 month. At 1 month, subjects receiving therapy will be allowed to cross over to injection treatment and all participants will receive as needed treatment until the 1 year period of follow-up. Thus only 1 month data is randomized but long term data will be gathered.

Inclusion Criteria:

1. Pain in the deltotricipital groove,extending down the lateral septum.
2. Pain rating 6 or more on a 0-10 numerical rating scale (NRS)
3. Reproduction of pain with provocative maneuvers. Lifting a 6 pound weight to 60 degrees with the below at 40 degrees of elbow extension and the clinician creating a flexion force on the elbow which the participant resists. (Need a picture)
4. Pain more than 3 months?

Exclusion Criteria:

1. Pain in other arm or shoulder locations on either side more than 2/10
2. Pain in other part of the body more than 4/10.
3. Taking narcotics for pain.
4. Pain with testing of shoulder laxity.
5. Massive rupture of rotator cuff (complete width tear) evidenced by examination or MRI scan.
6. Level III-IV or more shoulder arthritis on plain film of shoulder.
7. Other peripheral neuropathy.
8. Unstable psychiatric status