What is Hyperextension Injury of the Knee & How is it Treated?

Hyperextension injury of the knee is a potentially debilitating injury which is commonly suffered by athletes and sports people. The severity of the hyperextension injury of the knee depends on the cause of the injury and the athlete’s body and general health condition. Common symptoms of hyperextension injury of the knee consist of swelling, acute localized pain, decreased range of motion and instability on the injured leg.^[1]

Hyperextension injury of the knee occurs when there is excessive force placed on the knee joint and it is forced to extend or go beyond its normal range of motion. This injury occurs when huge amount of stress is placed on one or more of the major ligaments of the knee joint which include: anterior cruciate ligament (ACL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL) and medial collateral ligament (MCL). Anyone can suffer from hyperextension injury of the knee; however, this injury more commonly occurs as a result of sports injuries. Athletes competing in contact sports, such as soccer, football or lacrosse are at an increased risk to suffer from this injury. Skiing is one more sport where the knee joint can be forced to suddenly move out of its normal position resulting in hyperextension injury of the knee.^[2]

The severity of the hyperextension injury of the knee can be assessed by the method in which the injury was incurred. In mild injuries, patient will only have small amount of swelling or pain. If the injury is traumatic, then the hyperextension of the knee can cause damage to the surrounding cartilage, ligaments and soft tissues.

Excessive pressure or weight forces the knee joint into extension where the joint goes or extends beyond its normal range of motion resulting in swelling, soft tissue damage and potential strains or tears of the ACL, MCL, PCL or LCL. Some of the common causes of Hyperextension Injury of the Knee are:

• Unforeseen pressure or impact to the anterior part of the knee joint leading to backward movement of the knee joint resulting in ACL tear or strain; this type of impact is often seen in athletes where the football player is being tackled by the legs etc.
• Forcing the patella or femur over the tibia and putting excessive pressure on one or more of the major ligaments of the joint. Such type of impact can be experienced by a basketball player who stops abruptly and puts all of the body weight on one leg to do so.^[3]

There are different degrees of Hyperextension Injury of the Knee and symptoms of this condition depends on the manner in which the injury occurred, the overall strength of the knee joint and the athlete’s body. Hyperextension injury of knee can potentially cause serious damage to the surrounding ligaments and structures and patient feels immediate and severe pain.

Some of the common symptoms of hyperextension injury of the knee are:

• Acute pain is felt after the injury. Depending on the damage to the four primary ligaments in the knee joint, the extent of the pain varies.
• Patient who has sustained hyperextension injury of the knee will have symptoms of instability of the affected knee joint where it feels as if the knee is buckling or giving out.
• Symptoms of hyperextension injury of the knee will also include decreased mobility and limited range of motion of the affected knee joint due to pain, swelling and weakness in the knee joint.
• Fluid accumulation (knee effusion) can commonly occur within the knee joint after hyperextension injury of the knee. This condition is known as “water on the knee,” where the patient will also have reduced knee mobility.
• Bruising may also be present in the affected region if the hyperextension injury of the knee is severe so that it causes damage to the cartilage, ligaments and other soft tissues.^[4]

Diagnosis of hyperextension injury of the knee differs from patient to patient, as the severity of this injury is also broad. If the patient has suffered a severe or traumatic hyperextension injury of the knee, then there may be severe pain, bruising and ligament tear. In case of minor hyperextension injury of the knee, patient may have mild swelling and slight decrease in his/her mobility.

Diagnosis of hyperextension injury of the knee consists of three primary factors:

Medical History of the Patient: The doctor asks questions about the patient’s medical history before starting any treatment. If the patient has had prior knee injuries then he/she will be more prone to a more severe injury.

Physical Examination of the Patient: Physical examination is conducted to assess the severity of the injury. The patient’s range of motion is checked by moving the affected leg forwards and backwards. If the patient’s leg is locked then it indicates a more severe injury. The doctor will also look for swelling or bruising which can indicate a torn ligament and damage to other internal structures.

Imaging Tests: If the hyperextension injury of the knee is severe, then imaging tests will be done which commonly include x-rays and MRI of the affected knee joint/leg.^[5]

Treatment of hyperextension injury of the knee depends and differs from patient to patient. The treatment method depends on the patient’s medical history and general health and strength of the knee joint. Treatment also depends on the severity of the hyperextension injury of the knee, i.e. whether if there was damage to the ligament or cartilage etc. Common treatment methods of hyperextension injury of the knee include:

Medications such as NSAIDs (naproxen, ibuprofen) can be prescribed to help alleviate pain and swelling associated with of the hyperextension injury of the knee.

R.I.C.E. (resting, icing, compression, elevation) therapy to the knee joint is recommended.^[6]

Surgery is needed in cases of traumatic or severe hyperextension injury of the knee in order to repair the damage to the knee joint and other structures of the knee joint.

Surgery will consist of reconstructing and repairing ligaments and meniscus. Some of the common surgical procedures for severe hyperextension injury of the knee joint consist of:

Arthroscopy: In arthroscopic surgery, a remotely controlled, small endoscopic camera is inserted into the knee joint via an incision so that the surgeon is able to clearly see the affected area. Repair of some knee damage can also be done through this procedure.

Reconstruction: In reconstructive surgery, the damaged knee tissue is repaired. One of the common types of reconstructive surgery is ACL reconstruction. The nature of reconstruction surgery greatly depends on the exact nature of the injury and method in which the injury has occurred.

Recovery from surgery for hyperextension injury of the knee differs from patient to patient and depends on the severity of the injury. After the surgery, patient may need immobilization of the knee joint, needs to decrease his/her physical activities, and start physical therapy and training. Physical therapy should be started after complete healing has been achieved following the surgery. Physical therapy helps in restoring strength, flexibility and range of motion of the affected knee joint.

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