French to English Medical Medical (general)

The term “plateau évolutif” appears in a report written by a physician who reviewed a work accident case. In his report, the reviewer briefly summarizes the findings of each of the 30 or so visits the worker had with his treating physician over a 2-year period, which visits started in February 2010. From May of 2010 onward, the treating physician noted almost every time that the patient’s condition had not changed, with only one instance of “slight improvement” and two instances “condition has worsened”. The reviewing physician states that “le Dr X constate un plateau évolutif depuis mai 2010”. Is there an equivalent term for “plateau évolutif” in English or will I need to use a paraphrase (e.g., “…a plateau in the course of the patient’s injury”)?