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Explaining Casemiro's injury

Real’s Brazilian midfielder picked up a fibula fracture against Espanyol last weekend and has been ruled out for several weeks. 

International Champions Cup 2016 - Real Madrid v Paris Saint-Germain Photo by Kirk Irwin/Getty Images

Fibula fractures are quite common in football and frequently occur after a physical challenge where a direct blow is taken to the shaft of the bone; normally in the middle third as in Casemiro’s case if it’s an isolated break. If the fracture is in the lower third then this can be a complication of ankle injuries, or if the break is in the upper third of the fibula this can arise in conjunction with knee injuries.

The fibula is usually referred to as a non-weight bearing bone whose primary purpose is to provide attachments for the muscles of the calf and the lateral ligaments of the ankle and knee. Because of the involvement of the fibula in the lateral ankle complex, some weight-bearing is inevitable and various authors have proposed that the exact extent of this varies between 6.7% (Takabe et al, 1984) and 17% (Wang et al, 1996) of body weight. Although others may differ in opinion, some authors argue that the fibula bears no physical weight at all.

Anatomically speaking, the bones of the lower leg comprise the tibia, which is the thick weight-bearing shaft of the shin, and the long thin fibula which lies adjacent to the tibia on the lateral part of the limb. In the illustration below, the fibula can be seen extending down to form the ankle joint. The shaft is long and thin and therefore vulnerable to the usual kicks and direct blows that are normal in football.

Fractures of the fibula are often referred to as the footballers’ fracture. This is because the fibula is normally the bone affected when a player takes a knock on the outside of the calf during the match. We’ve often read in the past that somebody “valiantly played on although clearly in a lot of pain” only for the player in question to come out with a statement to the effect that the club allowed him continue to play despite the fact that he had a broken leg!

This obviously wasn’t the situation in Casemiro’s case, but due to the primarily non-weight bearing role of the fibula as described above, it does happen a lot elsewhere.

Since it is possible to weight bear in cases of fibular fractures the scenario probably takes place up and down the country where players try to “run it off” in the mistaken belief that it’s only been a kick. However, unless it’s blatantly obvious at the time, it’s actually very difficult to tell right away whether you are dealing with a simple bone bruising or a potential fracture. Apart from the lower third which provides the upper part of the ankle joint, the fibula itself is hard to palpate on examination due to the surrounding muscles of the calf to which it provides a platform for their attachments.

Casemiro was subbed against Espanyol as a precaution and the diagnosis of a fibula fracture came a few days later once investigations had been completed. This is the usual protocol to follow since a fair amount of swelling around the injury site had delayed the initial examination and subsequent diagnosis.

Various suggestions have been made about when he will return to the team ranging from three weeks to one – two months. At the moment it wouldn’t make sense for the medical people to jump in and make a prediction since proper healing is dependent on complete union of the bone.

The exact recovery time following fibula fractures is always difficult to predict. The average healing time for a fibula fracture tends to be around the six week mark but you also need to allow for the bone mineral density to be at the right level before returning to play; otherwise the risk of re-fracture is high.

With any fracture, once the initial inflammatory stage has passed, the natural reparative stage begins once the new cells start to form and then these begin to harden and mature into stronger bone. It’s only once the latter has taken place that the fracture is anywhere near healed. Some callus formation, which is basically the new bone formation surrounding the fracture site, should also be visible. Strength of the new bone is essential to the healing process and this is easily identified by medical imaging. When looking at the fracture site on a plain x-ray the bone should appear as white as the non-affected areas and this signifies good healing. It might be stating the obvious, but fractures that don’t clearly show the healing process on repeat x-rays generally need more time to recover.

Nowadays it’s rare for a player to suffer an immediate re-fracture on coming back from injury. Modern return to play protocols, check MRI scanning and specific fitness testing tend to exclude the potential for recurrence before the player is allowed to go back into the team. Additionally, the players are usually required to join in full training for a reasonable period before a return to play is considered. If there are any complications following fibula fracture it’s usually if the bone is affected at either end such as at the knee or ankle as described earlier.

However, it’s always worth bearing in mind that non-union of the long bones such as the fibula can become a problem dependent on the nature of the fracture and whether any displacement has occurred (Soucacos et al, 2006). Of course we don’t have access to that kind of exact information with regards to Casemiro’s injury but Madrid’s medical people will be managing the situation accordingly.

As the club rightly point out, his recovery will continue to be assessed and that’s probably the most accurate statement to make at this point.


Soucacos PN, Dailiana Z, Beris AE, Johnson E0 (2006). Vascularised bone grafts for the management of non-union. Injury; International Journal of the Care of the Injured. Vol.37 (1); Supplement S41 – S50.

Takabe K, Nakagawa A, Minami H, Kanazawa H, Hirohata K (1984). Role of the Fibula in Weight-bearing. Clinical Orthopaedics & Related Research. Available at the “Current Orthopaedic Practice” website. Accessed 24th September, 2016.

Wang Q, Whittle M, Cunningham J, Kenwright J (1996). Fibula and it’s Ligaments in Load Transmission and Ankle Joint Stability. Clinical Orthopaedics & Related Research. Vol. 330; 261 – 270.

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