What is a hyperextended knee?

A hyperextended knee is a common sporting injury where the knee bends backwards beyond its normal position. The severity of the injury can range from being a mild inconvenience to a serious injury. 

When do hyperextension injuries of the knee occur?

There are a number of ways for hyperextension injuries to occur, from getting your foot caught in a hole to someone jumping on your back from behind. However, the most common causes include: 

* An awkward landing that forces the knee back on itself whilst landing from a jump. For example: a netball player may get knocked off balance whilst in the air and land with a straight knee that then becomes hyperextended.

* An opponent striking the front of the knee whilst playing a contact sports such as rugby.

* A skier running into a bank of snow at speed and continuing to travel forward whilst the skis stop suddenly. This often happens when the heel binding doesn’t release and so the knee becomes hyperextended.


What are the symptoms of a hyperextended knee?

When a hyperextended knee first occurs a 'pop' sound can often be heard as the knee is forced backwards. The injury can cause pain, bruising and swelling. The knee swelling may come on quite quickly, within the first hour or two. In some cases, the knee ligaments could be torn, causing the knee to feel unstable. For more information about knee injury symptoms and diagnosis. 

What can be injured when the knee hyperextends?

The first step in treating any injury is to try and work out what has happened to the knee and then assess the severity. At its most serious, the knee can rupture all the major ligaments including the lateral collateral (LCL), medial collateral (MCL) and anterior cruciate (ACL). If this is the case, then the capsule or sac around the knee is usually torn so the knee may not swell. Although relatively rare, this is a very serious knee ligament injury and will require urgent attention. The knee would in most cases feel very unstable. You may also suffer with a loss of feeling in the lower part of the leg, if this happens you should seek advice immediately.

Hyperextended knee injuries that are painful and swell quickly often involve the anterior cruciate ligament (ACL). This is especially likely if there is a “pop” heard at the time of injury. Attempts to stand up on the leg may result in the knee feeling unstable or giving way. If you think that you have sustained this type of injury you should immediately seek advice from a specialist. At Wimbledon Clinics we specialize in the assessment and treatment of knee injuries. 

There are then injuries that don’t rupture the cruciate ligament, in these injuries the knee has hyperextended enough to cause a tear in one of the collateral ligaments, usually the medial collateral which is on the inside on the knee and likely to be very tender. 


What is the first thing to do if you think you have a hyperextended knee?

The first thing you need to do is try and rest the knee with it straight. Seek urgent help if the knee is severely painful, deformed or there is loss of feeling in the leg. If you can stand, then be cautious about bearing weight, but if you find that the knee gives way or buckles, then do not try to stand on it. If you can walk, get to somewhere where you can rest. 

In hyperextended knee injuries the knee may feel like it wants to bend backwards, so some form of support for the knee can be helpful. To identify the severity of the injury, see if you can bend the knee, then straighten it. The more significant injuries are usually too painful to bend.

For all knee injuries, then ensure you follow the following first aid protocol:

P-  prevent further injury

R-  rest

I-  ice the sore joint

C- compress with a bandage

E- elevate


What is the treatment for a hyperextended knee?

For minor injuries, you may be able treat by using the above first aid protocol, in addition to some pain medication such as paracetamol. Anti-inflammatories can also be useful for reducing pain as well as swelling if you tolerate them. Most minor injuries will settle down within a few days to a few weeks. 

For major injuries or an injury that persists beyond a few weeks you will require a proper assessment. Anything other than a minor injury will require a clear diagnosis and is where a specialist will assess exactly what has been injured and the severity of the injury.


How to recover from a hyperextended knee

For minor injuries (after the pain and swelling has been controlled) the next focus is on getting the knee moving. You can do this by carrying out a strengthening program. This will concentrate on strengthening the quads, hamstrings and calf. In minor injuries it is important to “listen” to the knee and progress as comfort allows.

For more significant injuries, you can also follow a strengthening programme, but you may also require a brace or crutches and may even require surgery. If you have this type of injury you need to have specialist advice and guidance throughout the recovery. Hyperextension injuries are difficult to self assess. Some of them require urgent care or surgery. 

If you are suffering from a suspected hyperextended knee or any other knee injury and need advice and specialist treatment, then contact us today and we’ll assess your injury and put together a clear strategy for treatment and recovery, so you can be back to your best as soon as possible.