When Alexander Isak had to be helped off the pitch limping right after putting Liverpool ahead against Tottenham, it was clear he’d suffered a major injury. Subsequent reports suggested a possible leg fracture, with speculation that he could be out for anywhere from weeks to months. On the surface, a broken leg sounds like one of the hardest injuries to bounce back from, but how does it actually compare to other common football injuries like an ACL tear?

What are the types of leg fractures? When comparing a broken leg to other injuries, the simplest answer is 'it depends on which bone broke and how badly.' In football, the most common leg fractures occur in the lower leg—the tibia and the fibula. A fibula fracture involves the smaller of the two bones, which forms the outside of the shin and isn't weight-bearing, making it one of the fastest types of leg fractures to recover from. These usually heal relatively quickly, taking about 6 to 8 weeks. Conversely, the tibia is the larger, stronger shinbone, and a fracture there can take 3 to 4 months to heal.

In much rarer cases, a player might fracture their femur (thigh bone). The femur is significantly stronger than the tibia or fibula and is less likely to take a direct hit during a game, so femur fractures are much less common in football. Even in these cases, recovery is around 3 to 4 months. "It all depends on the severity," sports physiotherapist Nick Worth told BBC Sport. "If it’s a simple fibula fracture from a kick to the side of the leg, they could be back in 6 weeks." However, he added that if the tibia is involved, it could mean "3 to 4 months out with conservative treatment." He noted that the severity determines if surgery is needed or if pins and plates are required, which can extend recovery time as they work to stabilize the fracture.

How do ACL injuries compare? ACL injuries are among the most feared in sports because the recovery time is notoriously long. The ACL is a band of connective tissue inside the knee joint that can be affected by a player's sudden change of direction or landing from a jump. "Because of the complexity of ACL surgery and knee reconstruction, it takes a long time to regain muscle strength and stability," Worth added. "The knee is a crucial structure for maintaining overall leg stability, so realistically 9 to 12 months are needed after reconstruction. People usually say 6 to 8 months, but it often takes longer to get back to peak condition."

While ACL injuries used to be considered 'career-enders' for some, advances in surgical techniques—like more effective patellar tendon or hamstring grafts—mean most players eventually return to the pro level. Hamstring injuries are also common but require less invasive treatment compared to fractures or ACL tears. They are graded from 1 (mild strain, days of recovery) to 2 (partial tear, weeks) to 3 (severe or complete tear, months). Even a grade 3 tear requires specialist care, but surgery is generally less essential for hamstrings than for fractures or ACLs.

Why do recovery times differ? One reason a leg fracture can be faster to recover from than an ACL is that rehab can start much earlier. "You can do a certain amount of work on a fracture from the early stages because bones heal through stress lines," Worth said. "Once the fracture settles and the pain subsides, putting weight or pressure on it actually stimulates bone growth, helping it heal better and faster."