Acromioclavicular (AC) Joint Arthritis

Evidence: Limited / Insufficient Evidence — ASPN 2024: Level III · Grade I

CAUSES

• Gradual degeneration
• A prior shoulder separation or trauma to the AC joint
• Repetitive overhead activity or heavy weightlifting

SYMPTOMS

• Pain localized to the very top of the shoulder
• Pain that worsens reaching across the body
• Tenderness with direct pressure over the joint

IMAGING

X-ray view best shows joint degeneration and osteophytes. MRI can be considered if there is concern for a coexisting rotator cuff problem.

CAN PRP HELP?

Less research exists for AC joint arthritis, and cortisone injection remains the more established first choice in this case. PRP can be considered as an alternative option once other measures have been tried or for patients for whom cortisone is contraindicated.

Leukocyte Preparation: Leukocyte-Poor, if pursued

Dosing: Single Injection

ASPN 2024 CONSENSUS GUIDELINE

ASPN grades AC joint pathology Level III, Grade I — evidence is thin and mostly case-report or narrative, and the panel considers it insufficient to judge one way or the other (a genuinely different verdict from a Grade D, which would mean evidence actively argues against it). One useful clinical pearl from the guideline: a type-3 acromion or existing AC joint arthrosis predicts a worse PRP response for an adjacent partial rotator cuff (supraspinatus) tear — so an AC joint injection shouldn’t be expected to rescue a poorly-responding cuff nearby.

Sources: D’Souza et al. (ASPN Consensus), Journal of Pain Research, 2024 · Berná-Mestre et al., AJR, 2020 · Vargas-Figueroa et al., Cureus, 2025

FREQUENTLY ASKED QUESTIONS

What’s the AC joint, and how is arthritis there different from arthritis in the shoulder itself?

The acromioclavicular (AC) joint is the small joint where the collarbone meets the shoulder blade at the very top of the shoulder. The GH joint is the larger ball-and-socket glenohumeral joint. AC joint arthritis causes pain localized to the top of the shoulder, often worse reaching across the body, rather than the deeper ache typical of glenohumeral arthritis.

Is PRP a first-choice treatment for AC joint arthritis?

No, a corticosteroid injection remains the more established first choice for this joint, since there isn’t much dedicated PRP research for AC joint arthritis specifically.

What does a “Level III, Grade I” evidence rating actually mean?

It means the evidence is thin and mostly case-report or narrative, and the ASPN panel considers it insufficient to judge one way or the other. This is still a different decision compared to Grade D, which would mean the evidence actively argues against using PRP.