This paper explains some of the challenges that exist to make accessible the web interfaces of a Tele-rehabilitation platform for hip arthroplasty patients and propose an iterative method to improve the level of accessibility using automatic evaluation tools. Web accessibility is not concerned with the specific conditions of people who use the Web, but with the impact that their conditions have on their ability to use it. If the web interfaces of the Tele-rehabilitation platform for hip arthroplasty patients are not accessible enough, the patients will not be able to understand, perceive or operate adequately the platform to benefit completely of the physical therapy. The Web Content Accessibility Guidelines (WCAG 2.0) provides a set of rules and recommendations to help solve the problems of Web accessibility. Additionally, there are evaluation tools that allow identifying main web accessibility problems. These tools are best exploited when used by accessibility experts. The purpose of this research is threefold. First, to present the results of a web accessibility evaluation of the web interfaces of the Tele-rehabilitation Platform for Hip Arthroplasty Patients using three the evaluation tools: WAVE, AChecker and TAW. Second, to analyze the results presented by the tools according to the WCAG 2.0 guidelines to define a list of accessibility improvements. Third, to implement the improvements through the re-factorization of the existing code and re-testing the improved web interfaces to verify that they meet acceptable accessibility levels.