BACKGROUND: Smartphone and wearable technologies are novel devices for monitoring postoperative mobility and recovery in total knee arthroplasty (TKA) patients. This systematic review of the highest-level evidence studies evaluated the advantages of these technologies in postoperative care, specifically focusing on: 1) smartphone applications, 2) wearable devices, and 3) their combined use. METHODS: A systematic literature search from July 26, 2015, to June 13, 2024, identified level 1 and 2 published studies investigating smartphone applications and wearables for monitoring post-TKA recovery. A total of 3,131 studies were screened, with 31 meeting inclusion criteria as follows: 18 focused on applications, eight on wearables, and five on both. The study quality was evaluated using the Coleman methodology scoring. Key metrics analyzed included patient satisfaction scores and adherences, functional outcomes, and pain scores, ranges of motion and gait analyses, and measurements and comparison tools. RESULTS: Among the level 1 and 2 publications, 17 of 18 studies on smartphone applications for postoperative recovery in TKA highlighted benefits, including patient satisfaction, improved gait, optimized pain management through medication scheduling guidance, cost savings, and better functional outcomes. Among the eight studies focused solely on wearable technologies, seven exhibited positive outcomes and demonstrated accuracy in monitoring and effectiveness in gait and motion analysis. Additional benefits included improved recovery outcomes, enhanced return to function, cost reduction, and better pain management through patient interaction and guidance. The five studies, which integrated both applications and wearables, corroborated these findings, emphasizing patient satisfaction and overall mobility enhancement at three months postsurgery. CONCLUSIONS: Smartphone applications and wearable devices offer enhancements in postoperative rehabilitation following TKA. Randomized trials validate their accuracy, effectiveness, and utility in this context. Improved adherence to care plans and medication schedules emerged as recurrent findings. These technologies and resultant data not only provide direct patient benefits but also promise potential cost savings.