Not sure what a letter to the editor would accomplish. The nature paper only interpreted radiographs and the only claim of the authors was basically that the model is a better predictor of pain than KLG.
Your comment misinterpreted this as “using the patients' symptoms and objective data” (when they only used objective data) and added “may actually outperform current medical standards” which was not the claim as current medical standards already consider patient symptoms in addition to objective data, as stated in the article reference to the TKA guideline.
When I report a joint xray I’m not assessing the patient’s pain level, they can be asked that.