Once again I completely disagree with cuseregular. Disc herniations are almost always very obvious and easy diagnoses. If your in orthopedics and can't diagnosis a herniated disc then you shouldn't be in practice.
I would say that disc herniations is garden variety medicine and any competent health care provider should easily be able to diagnose and manage them
A good sports medicine doctor should NEVER miss a diagnosis as major as a avascular necrosis.
dude sorry for the tone of this response as I'm mirroring you, but you're completely clueless on disc herniation related issues and the clincial nuances associated with them. How do I know this with certainty? Oh where to start?
First I guess I'll make mention that I personally have an L5 disc herniation I've been dealing with for 15 years following a hoops game (the final straw) at age 35. Been dealing with recurrent LBP episodes since age 22 and with every episode the orthopedic testing evaluation was completely unproductive short of reduced motion issues and spasms found with any generic low back pain syndrome. And there was no consistent radicular leg symptoms and when there was it was infrequent. So now without any certainty with respect to disc concerns (negative ortho findings, no leg Sciatica symptoms characteristic of disc displacments), so what do you do?
Well since my friend runs a local MRI facility what you do is do an MRI and lo and behold there it is, a large L5 disc herniation (Protruding and mostly contained). Not exactly straight forward now is it in that scenario now is it?
How else do I know? Well being a college prof some 22 years now teaching orthopedics, neuro/spinal anatomy/neurophysiology you get a lot of exposure to related issues. For example with being exposed to and sometimes a part of clinical trials and studies; it's a well known fact that over 50% of the population over the age of 35 who are asymptomatic showing no pain symptoms, it's a fact that some 50-55% of them show up as having lumbar disc herniations. According to your logic of how "garden variety" disc hernations are well then all of them should have positive orthopedic findings for disc herniations. Anyone can google this fact and see the multiple studies and we at the college on a smaller scale have confirmed it in our unpublished look at this issue.
Well guess what, they don't. Why? Well this is where nuance comes in with associated factors and variable involved that do not allow for much in orthopedics to be cut and dry and 'garden variety'. Everyones anatomy is different to a certain exent and in the case of spinal issues and discs some people have larger spinal canals than others allowing them to accomodate a disc problem better such that they may never be symptomatic. Worse yet was the fact that until 15-20 years ago drs. used these MRI finding for an automatic reason to do surgery where as in point of fact that particular finding may frequently be coincidental.
This is why they call our professions "practices" because that's exactly what they are in that it is an art and a science. Even if someome is not showing traditional disc signs a competent practioner still has it in the back of their mind, especially so with advancing age and each recurrent back pain episode. Being in a health care practice environment some 21 years now you treat a lot of these cases and learn these facts after thousands of cases.
Furthermore, most textbooks on back pain and orthopedics associated with it will say that of all back pain somewhere around 14-18% of it are related to "disc herniation". These are the people with characteristic signs and symptoms of sciatic radiculitis, reduced lumbar flexion, productive (+) SLR with associated qualifiers (Braggard, Bonnets, Etc), or using your terms these are the "garden variety" cases of disc displacements.
So the astute practioner understands that the generally accepted number of 14-18% of LBP being related to disc herniation is actually ridiculously low and much higher due to nuance of individual circumstances (spinal canal size, type of herniation protrusion vs. prolapse, and the differing vaiable of each patients unique pain tolerance profile). This is how missed diagnosis occur. So very common.
Now with AVN the same nuance is true as well. It takes a while for the major symptoms to show up until sufficient damage is done to allow the diagnosis to finally occur. The pain is subtle at first and not particularly intense at first so it can evade detection do to it's rarity. It's not garden variety this issue and not the first thing that one thinks of with a limping patient who likely hasnt sustained a particular trauma. And when early on the orthopedic evaluaton is still non productive you still don't think about this. However, a few weeks into it (3-5) weeks if the patient is still having issues then it gets into your mind as a possible concern.
Nuance. If you're in health care in your early years you'll start to see it with patients. And if you are in it a while and you're not seeing it it's time to open your eyes.