UFC 239 · July 6, 2019
Thiago Santos Fought Five Rounds with Four Torn Ligaments
Thiago "Marreta" Santos challenged Jon Jones for the UFC light heavyweight title at UFC 239 on July 6, 2019. Post-fight imaging revealed that Santos had reportedly torn his ACL, PCL, MCL, and medial meniscus during the fight — yet continued competing for all five rounds, losing by split decision in one of the closest Jones fights in his title reign.
What happened at UFC 239
Jon Jones defended his light heavyweight title against Thiago Santos in a closely contested five-round fight at T-Mobile Arena. Santos entered as a significant underdog but went toe-to-toe with Jones for the entirety of the bout, landing significant strikes and challenging Jones in ways few opponents had. The judges awarded Jones the decision by split — one judge scored it in favour of Santos — making it one of the most competitive fights of Jones's title reign.
Following the fight, Santos revealed that his left knee had been compromised during the contest. Post-fight MRI confirmed the extent of the damage: tears to the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), medial collateral ligament (MCL), and the medial meniscus. Santos required surgery to address the multi-ligament injury and underwent an extended recovery before returning to competition.
What four torn knee ligaments actually means
The knee has four primary ligamentous stabilisers. Tearing all four — the ACL (anterior stability), PCL (posterior stability), MCL (medial/valgus stability), and meniscus (load distribution and secondary stability) — constitutes one of the most severe knee injury patterns in sport. In most clinical contexts, this degree of ligamentous disruption represents a true knee dislocation or near-dislocation, and is associated with a significant risk of popliteal artery injury that can threaten limb viability.
The fact that Santos completed five competitive rounds of elite MMA with this injury pattern is medically extraordinary. The explanation likely involves: the injury occurring gradually across multiple exchanges rather than a single catastrophic event; dynamic muscular stabilisation compensating partially for ligamentous insufficiency; the adrenaline and competitive context suppressing pain perception; and the specific pattern of injury being more tolerable for forward-plane movement (punching, kicking) than for the lateral agility and direction-change demands that would fully expose a multi-ligament knee.
Orthopaedic surgeons who commented publicly on the case emphasised that Santos's case is an extreme outlier — most athletes with four-ligament involvement cannot continue activity and require emergency assessment. The absence of vascular compromise was presumably confirmed before Santos continued; the specifics of in-cage medical assessment are not publicly documented.
Santos's recovery and return
Santos underwent multi-ligament knee reconstruction — a complex surgical procedure requiring staged or combined repair of the ACL, PCL, MCL, and meniscus. He returned to MMA competition in 2020, eventually challenging Glover Teixeira for the light heavyweight title at UFC 256 in December 2020 — approximately 17 months after the UFC 239 injury. His return at championship level, less than 18 months after multi-ligament reconstruction, is considered a rapid return by orthopaedic standards for this injury pattern.
Full Rehab Guide
Multi-Ligament Knee Injury
Full clinical guide to multi-ligament knee injuries — how multiple ligaments tear simultaneously, surgical planning, and the 12–18 month rehabilitation timeline for elite athletes.