Background: Tendon lesions affecting the proximal rectus femoris (PRF) muscle represent about 1.5% of hip injuries. Most acute cases are managed conservatively with physiotherapy. There is a lack of consensus regarding surgical intervention for chronic injuries. This article, alongside a literature review, presents a case of anatomical surgical reinsertion for chronic complete avulsion rupture of the PRF tendon. Case Report: A 34-year-old amateur athlete experienced acute inguinal pain from overexertion, with conservative treatment having failed over 3 months. Seven months later, proximal tendon rupture involving both PRF muscle heads was confirmed. An anterior Hueter approach released the tendon from the adhesions and fibrosis. The direct portion was reinserted into the inferior anterior iliac spine, and the reflex portion was reattached to the supraacetabular groove. The patient showed excellent improvement on the modified Harris Hip and Lysholm–Tegner scales. The quadriceps muscle force decreased by 20% compared to the contralateral leg at 3 months, reducing to 4% by 12 months. Normal activities resumed after six weeks, and sports resumed after 4 months. Conclusions: The patient experienced significant postoperative improvement, as shown by the enhanced functional scores and muscle force recovery over one year. The success of the anatomical reconstruction in restoring tendon continuity underscores the importance of tendon healing mechanisms, including tissue remodeling and revascularization, in chronic avulsion injuries. This case highlights the efficacy of anatomical reconstruction for chronic PRF tendon avulsion. The literature review offers further insights into treatment options and the physiological basis of recovery for such injuries.
