Inter- and Intra-Observer Reliability of the Iowa Level of Assistance Scale and the Effect of Staff Retraining

Inclusion Criteria: * For Observers (Physiotherapists): All physiotherapists working at the main Istituto Ortopedico Rizzoli (IOR) site in Bologna or at the two satellite sites in Argenta and Bagheria. Physiotherapists must have the role of observers in the study. All physiotherapists affiliated with the SAITeR service who have previously received initial training in the use of the ILoA scale; newly hired staff must have completed the specific training pathway. For Patients: Patients admitted to IOR Bologna or Argenta for whom administration of the ILoA scale is part of routine clinical practice. Patients undergoing primary hip or knee arthroplasty for osteoarthritis. Patients undergoing revision hip or knee arthroplasty. Patients undergoing hip arthroplasty or osteosynthesis for femoral fracture. Exclusion Criteria: * Refusal or inability to provide informed consent (for both physiotherapists and patients).