Presented independently designed hip and knee joint mechanisms for integration into a smart hospital bed with continuous passive movement (CPM). Built and analyzed in CATIA, the mechanisms showed stable motion and replicated about 67.19% of natural flexion–extension angles, with discrepancies mainly due to software and prototype limitations. Overall, the system effectively mimicked key lower-limb movements. Future work should focus on adjustable anthropometrics, real-time biomechanical feedback, and clinical validation.