That definitely sounds like spondyloarthritis. There are several kinds - psoriatic arthritis falls under the SpA umbrella, of course Ankylosing Spondylitis is the classic and more severe form of the disease (in terms of radiographic/x-ray damage) and so does enteropathic arthritis, which is what it is called when IBD is involved.
Spondyloarthritis is also classified by the joints that are involved. Axial SpA affects the spine. Have you had any lower back or butt pain? SI joint arthritis is usually the first sign of axial SpA.
Peripheral SpA affects joints other than the spine. The lower limb joints are commonly affected - the knees, hips, ankles but any joint can be affected.
Another feature of SpA is enthesitis which is inflammation where tendons and ligaments insert into the bone. Heel pain (where the achilles tendon meets the bone) is VERY common - probably the most common type of enthesitis. Elbow pain could also be enthesitis or arthritis (inflammation in the joint).
Common treatments are MTX for peripheral arthritis. You may need a higher dose - you can go all the way up to 25 mg. Sulfasalazine is sometimes used but it is weaker than MTX, so you're probably better off upping MTX.
MTX and Sulfasalazine do not work for SI joint or spinal arthritis, so if you have that (in addition to the peripheral joint pain), then a biologic would be your best bet. To rule out SI joint inflammation, usually an MRI is needed.
The biologics used are Remicade, Humira, Simponi and Cimzia - all anti-TNFs. All four of those would also work for your Crohn's.
If you have just peripheral involvement, then Stelara is also a good choice. It's an IL-23 and IL-12 inhibitor. Stelara failed in a trial for Ankylosing Spondylitis (AS), so it's not the best choice if your SI joints or spine are involved.
For the rheumatologist, can you ask to be placed on a cancellation list? That is what we do. I have two daughters and a husband with AS.
This is a good explanation of the types of arthritis associated with IBD:
http://www.crohnscolitisfoundation.org/assets/pdfs/emr/arthritiscomplications.pdf