The Canadian researchers grouped the most common symptoms, and the most important rehabilitation goals in different overarching themes: pain, sleep, limiting or avoiding activities, aesthetic appearance, and irritation from pressure on the joint. The researchers identified 38 items: patients with instability recognised themselves in 28 items and OA patients in 20 items.
Both patient groups agreed upon about a third of the 38 items. Both patients with instability and patients with OA experience clear localised pain around the AC joint, experience pain when reaching crosswise in front of the body, cannot sleep on the affected side, have difficulty carrying objects when the arms are along their body, often experience a clicking sensation around the joint and have difficulty turning their arm on their back which makes it difficult to fasten a bra or scratch their backs. They also report fatigue or loss of strength during daily activities or sports, and swimmers changed from front crawl to breaststroke. Many are reluctant to use their affected arm due to fear of pain or loss of control, and pressure on the joint by the strap of a bra, a seatbelt or a backpack for example irritates or is even unbearable.
Even though patients with instability or OA of the AC joint experience partly the same complaints, there are items which are unique to one of both patient groups. OA patients often report a burning sensation around the joint while patients with instability rather experience a dull pain. Pain when the arm is alongside the body, for example while walking or running, is unique for patients with instability, while patients with OA notice that they experience pain when they generate force alongside the body, for example when pushing up from a chair. Pain in different positions is more in the foreground with patients with OA, while patients with instability complain more about loss of strength and coordination. Patients with OA patients report pain in rest and when their arm is sideways (for example on the backrest of a couch) or above their head; patients with instability experience fatigue and loss of strength when they work above their heads. Patients with OA seldom mention anything about the cosmetic aspects, while a bulging clavicula is uncomfortable for some patients with instability. Patients with instability sometimes experience pain or cramp in the upper back or neck or have the feeling that their scapula is sticking out; patients with OA do not report this. However, researchers think they should be cautious about these findings: they only interviewed a small number of patients and the conversations did not have the purpose to determine differences between both groups. The fact that some items were not mentioned by one of both groups, does not exclude them from playing a role at all.