"Patellar Tilt" is essentially a finding/abnormality based on the X-ray study, not on the physical examination. It is seen on the Tangential or Sunrise view of the Patella. As such, for ICD-10, the M22 Code Set for Disorder of the Patella is totally lacking of the "specificity" needed for this diagnosis. There are several possibilities: M22.2X _: Patellofemoral disorders; M22.3X _: Other derangements of the patella; and M22.8X _: Other disorders of the patella. As usual, "Other" applies to "none of the above." M22.2X _ is for Patellofemoral disorders, which implies that the problem involves both the Patella and Femur, which "Patellar Tilt" does not. I frankly don't know the difference between "disorder" and "derangement" as it applies to the Patella. From my perspective, they are the essentially the same. I even looked them up in the dictionary and couldn't find any significant difference in their definitions. Based on that, I would say that both M22.3X _ or M22.8X _ would be correct, with M22.3X _ being slightly more specific.
Furthermore, I can not figure out why there is a 5th Character X in M22.2X, M22.3X, or M22.8X. The 5th Character could have simply been for laterality. If someone can explain/justify that for me, I would appreciate it.
Hopefully this will help (some).
Respectfully submitted, Alan Pechacek, M.D.
icd10orthocoder.com