Postoperative regular use of a self-rehabilitation mobile application for more than two weeks reduces extension deficit and cyclop syndrome after anterior cruciate ligament reconstruction

PURPOSE: To investigate the minimum use that correlates with the best outcomes in term of complications associated with self-directed rehabilitation mobile application and to explore the user profile and usage habits. METHODS: This was a single-center retrospective study of 356 patients who underwent ACL reconstruction surgery between November 2019 and August 2020. Complications were defined as the presence of an extension deficit ≥ 5° after 6 weeks and/or the presence of cyclops syndrome. The demographics, sports competition level and number of connections were collected by the application. RESULTS: The complication rate was reduced 4.2-fold with at least 2 weeks of use (2.4% (3/123) (with 0.8% (1/123) of cyclops syndrome) versus 10.8% (23/212) (with 3.3% (7/212) cyclops syndrome), p = .04). The mean duration of use was 20 ± 23 days with a frequency of 2.1 ± 2.3 connections per day. The usage rate was 50% in week 1, 35% in week 2, and 24% in week 3. There was one peak in the abandon rate during the first few days of use and a second peak at Day 10 when physiotherapy sessions started. There were two dips in the abandon rate associated with the follow-up visits at Days 21 and 45. Greater use was found in older patients (p = .0001) and female patients (p = .04). CONCLUSIONS: When using the application for a minimum of 2 weeks, the risk of complications was reduced 4.2-fold. The typical users of a self-directed rehabilitation application after ACL surgery in this study were women and patients over 30 years of age. LEVEL OF EVIDENCE: IV, retrospective.