Introduction: Rehabilitation following total knee arthroplasty (TKA) includes various therapeutic interventions, such as continuous active motion (CAM) and continuous passive motion (CPM). This meta-analysis aimed to compare the effects of CAM and CPM on pain, function, and range of motion post-TKA, focusing on the early postoperative period. Methods: A systematic literature search was conducted in databases including Medline, Cochrane Library, Embase, and CINAHL to identify randomized controlled trials (RCTs) comparing CAM and CPM post-TKA. Studies were required to include at least two postoperative measurements and combine the interventions with standard physiotherapy. The methodological quality of the included studies was assessed using the JBI appraisal tool, and statistical analysis was performed on suitable studies. Results: Seven RCTs involving 501 patients were included. Meta-analysis indicated significant pain reduction and improved functional outcomes with CAM compared to CPM, particularly in postoperative pain assessments. CAM showed advantages in functional tests, including the Sit-to-Stand and Timed-Up-and-Go tests. However, no significant differences were found for active and passive range of motion (ROM). Patient-reported outcome measures (PROMs) showed high heterogeneity, limiting clear conclusions. Conclusions: CAM demonstrates significant benefits in pain reduction and functional recovery compared to CPM following TKA. However, variability in outcome measures and intervention protocols limits comparability across studies and therefore generalizability. CAM’s requirement for active patient engagement may present practical challenges, while CPM’s standardization allows for easier integration into routine postoperative care.

Introduction: Total hip arthroplasty (THA) is a highly successful surgical intervention, yet the assessment of postoperative physical function lacks standardization. This systematic review investigates the variability in outcome measures used to evaluate physical function following THA over the past 12 years. Methods: Following PRISMA guidelines, we analyzed 406 randomized controlled trials (RCTs) from PubMed, Ovid, ScienceDirect, and Epistemonikos, focusing on studies published between 2013 and February 2025. Outcome measures were categorized into patient-reported (PROMs), performance-based (PBOMs), and impairment-based (IBOMs) measurement tools. Data extraction included study design, measurement types, and temporal trends. Results: Significant heterogeneity was observed, with PROMs employed in 95% of studies (e.g., Harris Hip Score, WOMAC), while PBOMs (18%) and IBOMs (22%) were underutilized. Only 8% of studies combined all three measurement types. PROMs dominated surgical studies (97%), whereas PBOMs and IBOMs were more prevalent in rehabilitation research. Temporal analysis revealed stable PROM usage but declining PBOM and inconsistent IBOM adoption. Conclusion: The lack of standardized functional assessment complicates cross-study comparisons and meta-analyses. While PROMs provide valuable patient perspectives, their limitations necessitate complementary objective measures. We advocate for the adoption of core outcome sets, such as those proposed by OMERACT, to improve consistency in THA outcome evaluation. Future research should integrate PROMs, PBOMs, and IBOMs for a comprehensive assessment of postoperative function.