Business decision to close study due to slow enrollment.

This is a prospective, single-center, randomized, comparative, controlled study. Penn Medicine Princeton Medical Center will enroll a total of 296 subjects (18 years or older) who are electing to have total knee or hip replacement surgery. Subjects will be randomized to either the treatment group (Health Partner alongside standard care) or the control group (standard care alone). Health Partner is a combination of a mobile application and a web-based portal. The primary objective is to compare care plan adherence (pre- and post-surgery) for Health Partner vs. control subjects. Secondary objectives include evaluating all-cause medical resource utilization, communication with health care provider, well-being, fear of surgery, confidence in recovery from surgery, sleep, and patient satisfaction for 90 days post-surgery.

Subjects meeting all the following specific criteria will be considered for participation in the study:

1. Subject is 18 years or older at the time of consent.
2. Subject must be identified by their provider as needing elective unilateral TKA or THA.
3. Subject must have a valid e-mail address and willing to access their inbox on a regular basis.
4. Subject must possess a smartphone/device capable of downloading the current version of the Health Partner mobile app and be willing to access and use digital materials for this project.
5. Subject must be able to comprehend and comply with the requirements of the study.
6. Subject must be able to speak, read and understand English fluently.
7. Subject is willing to give voluntary, written informed consent to participate in this service evaluation and authorize the transfer of his/her information to the Sponsor and Business Associate.

Subjects will be excluded from participation in the study if they meet any of the following criteria:

1. Subject is not able to follow the standard of care and would require special care or circumstances.
2. Subject scheduled to have TKA or THA less than or equal to 2 weeks (14 days) from the time they are enrolled in the study.
3. Subject is undergoing a revision to a previous surgery.
4. Subject is undergoing TKA or THA following traumatic injury (i.e. fracture).
5. Subject is expected to need another lower limb joint replacement (hip/knee) prior to completing this service evaluation.
6. Subject is a repeat patient and was enrolled in the study previously.
7. Subject has had prior experience with the Health Partner companion app.
8. Subject is currently involved in any personal injury litigation, medical-legal or worker's compensation claims.
9. Subject, in the opinion of their healthcare provider, is a drug or alcohol abuser (in the last 5 years) or has a psychological disorder that could affect his/her ability to complete patient reported questionnaires or be compliant with follow-up requirements.
10. Subject was diagnosed and is taking prescription medications to treat a muscular disorder that limits mobility due to severe stiffness and pain such as fibromyalgia or polymyalgia.
11. Subject has a significant neurological or musculoskeletal disorder(s) or disease that may adversely affect gait or weight bearing activities (e.g., muscular dystrophy, multiple sclerosis, Charcot disease).