"We believe one of the best ways to empower consumers is by giving them the ability to use their health and activity information to improve their own care," Apple COO Jeff Williams said in a statement. "We are proud to enable knee and hip replacement patients to use their own data and share it with their doctors seamlessly, so that they can participate in their care and recovery in a way not previously possible through traditional in-person visits."

Along with the app, Apple and Zimmer Biomet are working on a clinical study that will assess how mymobility impacts patient outcomes and costs. During the study, up to 10,000 patients will use an Apple Watch and mymobility as they work up to and recover from their knee or hip replacements. For now, only patients enrolled in the study will be able to use mymobility, but the company plans to roll it out to everyone in the future, CNBC reports.

This isn't the first time Apple has participated in such a study. Last year it teamed up with Stanford Medicine on a study to investigate how Apple Watch can be used to detect irregular heartbeats, and it just donated 1,000 Watches to the University of North Carolina for a study on eating disorders.

And these efforts are just part of Apple's strategy as it moves to have Apple Watch recognized as a health monitoring tool. With its ResearchKit platform, groups have developed ways for Apple Watch to spot signs of a stroke and monitor Parkinson's disease symptoms, among other applications. Last year, the FDA approved the first EKG band for the Apple Watch.

"We are incredibly excited to work with Apple to transform the knee and hip replacement experience for patients and surgeons," said Zimmer Biomet CEO Bryan Hanson. "At Zimmer Biomet, we are committed to improving care decisions through digital health and we are thrilled to launch one of the largest evidence-gathering clinical studies in orthopaedic history."