Injuries are part and parcel of football and most players will experience them in one form or another throughout their careers.
However, some injuries are more severe than others and can affect how a player plays the game. Indeed, some can even threaten a player's entire livelihood.
A cruciate knee injury is one that gives footballers nightmares and makes fans wince, but what is it exactly? Goal brings you all you need to know about the affliction.
WHAT IS A CRUCIATE LIGAMENT INJURY?
A cruciate knee ligament injury is what happens when one or more of the ligaments connecting the femur (thigh bone) to the tibia (shin bone) are torn or ruptured. There are a number of these ligaments inside the knee in order to stabilise and protect the leg from overextension.
Perhaps the most common cruciate injury is an anterior cruciate ligament (also known as ACL ) injury. Indeed, of the 28 knee injuries suffered by Premier League players in the 2016-17 season, 17 of those were ACL injuries.
The reason an ACL injury strikes fear into the hearts of football folk worldwide is because it can require a recovery period of six to nine months , which can seriously scupper the plans of players and managers alike.
The ACL is located inside the knee and works in tandem with the posterior cruciate ligament ( PCL ) to prevent the femur and tibia from overlapping. The PCL is also found inside the knee, but it is bigger and usually stronger than the ACL.
Other knee ligaments prone to injury are the lateral collateral ligament ( LCL ) and the medial collateral ligament ( MCL ), which are located on either side outside of the knee.
Why is it common in football?
Due to the nature of football, which involves plenty of jumping, twisting and turning, as well as physical impact, cruciate knee injuries are a common mishap on pitches around the world at all levels.
The ever-increasing intensity of professional football at the highest level, with clubs and players pursuing success, has coincided with an upsurge in cruciate ligament injuries, leading some pundits, such as former Chelsea player Pat Nevin, to brand it an epidemic.
Footballers can become especially prone to the injury if they are suffering from fatigue, something that can occasionally occur during a busy period of matches.
CAN YOU PLAY AGAIN AFTER A CRUCIATE INJURY?
The short answer is yes. That was not always the case, though, and in days gone by a cruciate knee injury was sometimes considered the death knell for a player's career.
However, medical advances mean that surgeons are able to treat the injury in ways they previously could not and, depending on the severity, players are usually able to make a return to the game.
Cruciate ligament injury treatment
It normally takes a couple of days for doctors to properly diagnose the extent of a cruciate ligament injury, because they must wait for swelling to subside before taking conclusive scans or carrying out tests.
In cases of minimal damage, individuals can get away with resting, wearing a knee brace and engaging in light physiotherapy, but in many cases, where there is a complete rupture, reconstructive surgery is required in order to ensure the player can play again.
The purpose of a knee brace is to both protect the area from being affected by impact and limit movement in order to allow the ligament fibres to successfully heal.
As mentioned, a player can expect to be sidelined for six to nine months with a cruciate ligament injury and that recovery period can even be longer in some cases, depending on the type of tear and subsequent treatment.
PLAYERS WHO HAVE SUFFERED CRUCIATE INJURIES
Cruciate ligament injuries affect players at all strata of football and, despite the extensive measures that are taken to prevent it at the top level, some of the best footballers in the world have nonetheless experienced it.
One of the most recent examples of a player to be laid low by a cruciate ligament injury is Zlatan Ibrahimovic, who tore his ACL back in April while playing for Manchester United against Anderlecht in the Europa League.
The injury appeared to have brought an end to Ibrahimovic's Man United career, but the 35-year-old remains defiant that he will continue to play and has shared a number of videos depicting his recovery progress .
The former Barcelona and Paris Saint-Germain star suffered the injury when he landed awkwardly after challenging for a header and it came amid complaints from Jose Mourinho that his team was playing too many games. Coincidentally, Ibrahimovic's team-mate Marcos Rojo also injured knee ligaments in the same game.
World Cup winner Marco Reus has endured a difficult number of years thanks to a series of injuries and he was dealt a further blow while playing for Borussia Dortmund in the final of the DFB Pokal against Eintracht Frankfurt in May. Reus suffered a partial cruciate ligament tear in his right knee and underwent surgery in order to improve his chances of a full recovery.
The Germany international revealed in June that he had a long period of rehabilitation in front of him following the surgery and he is likely to miss the majority of the 2017-18 season. However, he has stressed his desire to return to full match fitness in time for the 2018 World Cup in Russia, having been ruled out of the 2014 World Cup thanks to an ankle injury.
"The surgery went fine and I'm already on the road to recovery," Reus wrote in a post on his social media pages. "Now there is a relatively long rehab phase which I will follow. I will tackle this with everything I have and I'll do anything to be back soon on the pitch."
Long before Roy Keane's infamous assault on Alf-Inge Haaland, roles were reversed as the Norwegian stood menacingly over the prostrate Irishman during a 1997 clash between Manchester United and Leeds United. Keane had inadvertently hurt himself in the process of trying to tackle Haaland and later revealed in his first autobiography that he "actually heard [his] cruciate snap."
The cruciate ligament injury required surgery and ruled Keane out for the majority of the 1997-98 season as United lost out to Arsenal in the race for Premier League glory. However, he returned from the set-back to lead Alex Ferguson's team to a historic treble as the Red Devils won the Premier League, FA Cup and Champions League in 1999.
Keane went on to play for another eight seasons before hanging up his boots at the conclusion of the 2005-06 season.