Purpose: The aim of this study was to critically examine the content of smartphone apps produced for patients undergoing total hip replacement and total knee replacement surgery.Materials and methods: A systematic search was conducted across the five most popular smartphone app stores: iTunes; Google Play; Windows Mobile; Blackberry App World; and Nokia Ovi. Apps were identified for screening if they: targeted total hip replacement or total knee replacement patients; were free of charge; and were in English. App quality assessment was conducted independently by three reviewers using the Mobile App Rating Scale.Results: 15 apps met the inclusion criteria. On the 5-point Mobile App Rating Scale, the mean overall app quality score was 3.1. Within the Mobile App Rating Scale, the "Aesthetics" subscale had the most inconsistency across all apps, generating the highest and lowest mean scores (4.7 and 1, respectively). The "functionality" subscale had the highest mean score (3.8) among the four subscales, and the "information" subscale had the lowest mean score (2.7).Conclusion: This study highlights that despite a wide range of apps currently available to total hip replacement and total knee replacement patients, there is significant variability in their quality. Future efforts should be made to develop apps in partnership with patients, to improve the content, interactivity and relevance of apps.Implications for RehabilitationClinicians and rehabilitation professionals should consider that patients are using Smartphone apps to supplement their rehabilitation and be aware of currently available apps.Although some apps show promise, at present there is no one openly available app which is clinically recommended for rehabilitation use following total hip replacement and total knee replacement.Rehabilitation professionals tailor recovery programmes to individual patient needs following total hip replacement and total knee replacement, and future apps should also consider personal needs.We recommend that patients are involved in all stages of designing and testing future total hip replacement and total knee replacement rehabilitation apps.