Mitral valve repair using the free-knot technique: A simple, precise, and length-stable method for expanded...

Artificial chordal implantation using expanded polytetrafluoroethylene (ePTFE) is widely adopted in mitral valve repair (MVr). However, achieving precise chordal length remains challenging because durable valve competence depends on fine intraoperative adjustment. Moreover, ePTFE sutures are slippery and may change in length during knot-tying, making stable fixation difficult. The free-knot technique enables incremental intraoperative length adjustment and maintains the intended length without alteration during final knot fixation. This study aimed to describe the free-knot technique and evaluate its short-term clinical and echocardiographic outcomes.

We retrospectively analyzed 118 consecutive patients who underwent MVr using the free-knot technique between April 2021 and March 2025 at a single institution.

The mean age was 59.4 ± 11.4 years, and 48% were male. Posterior, anterior, and bileaflet prolapses were present in 66.1%, 17.8%, and 16.1% of patients, respectively. All patients underwent annuloplasty, with a mean of 2.3 ± 1.1 artificial chordae implanted. None of the patients had moderate or severe residual mitral regurgitation findings at discharge. Freedom from recurrent moderate or greater mitral regurgitation was 92.9% at 1 year, 90.2% at 2 years, and 85.2% at 3 years. Freedom from severe MR and reoperation remained 100% throughout follow-up, with no significant difference in MR recurrence according to the prolapse site.

The free-knot technique is a simple, adjustable, and device-free method that ensures accurate chordal length tuning and stable fixation without length changes during knot-tying. This approach achieved excellent short-term outcomes across diverse prolapse sites, supporting its value as a versatile tool for contemporary MVr.