Knee Injuries From Falling on Concrete: Why it Hurts & When to Worry

The knee is one of the most commonly injured joints of the body. Injuries of the knee can be caused by twisting of the knee, a direct blow to the knee, or impact when you fall or slip and your knee hits a hard surface such as concrete.

What Happens if You Fall on Your Knee Really Hard?

Falling and hitting your knee on concrete can result in various types of injuries ranging from mild bruises that can be treated at home to severe fractures that may require surgical intervention.

Below are the most common types of knee injuries resulting from an impact:


Abrasion, sometimes called a scrape or a graze, involves damage to the skin when it rubs against a rough or hard surface. It is classified into first, second, and third degrees depending on the severity of the injury. 

  • A first-degree abrasion only affects the first layer of the skin (called the epidermis) and it does not cause bleeding. 
  • A second-degree abrasion affects both the first and second (called the dermis) layers of the skin, which can bleed mildly. 
  • Lastly, a third-degree abrasion, also called an avulsion, results in damage beyond the first two layers of the skin, causing profuse bleeding which may require medical attention.

Table 1: Degree of Abrasion

Degree of AbrasionBleeding
First Degree (1°)Absent
Second Degree (2°)Mild bleeding may be present
Third Degree (3°)Profuse bleeding


A laceration is a deep cut on the skin that is usually uneven or jagged. There is no missing skin like in abrasion as the cut directly penetrates the skin, and it is frequently infected with bacteria or contains some of the pieces of the material that caused it, such as shards of glass.

Treatment for lacerations can be done at home or may need medical care depending on how deep the cut is.


When your knee hits a hard surface, the impact can cause the blood vessels of the skin and the muscle to rupture resulting in a contusion or a bruise. This makes the blood leak around the area of impact, producing the purplish to blackish color seen on the surface of the skin.

A bruise can be painful and tender when touched, but it can be managed at home through rest and pain medications if necessary.

Knee Ligament Sprain Or Tear

A sprain indicates an injury to the ligament. Knee ligaments help support and stabilize the joint and hinder unnecessary movements. A high-impact force or blow to the knee can damage any of the knee ligaments which include:

  • Cruciate ligaments, consisting of the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL), which prevent your knee from moving forward or backward excessively.
  • Collateral ligaments, consisting of the medial collateral ligament (MCL) and the lateral collateral ligament (LCL), which keep your knee from moving extremely sideways.

A knee sprain is classified into Grades I, II, and III.

  • A Grade I sprain signifies a mild stretch resulting in micro-tears that usually heal on their own.
  • Grade II indicates that the ligament is partially torn, which can result in pain and some instability.
  • A Grade III sprain implies that the ligament is completely torn, causing severe pain, swelling, instability, and difficulty in walking, which warrants immediate medical attention.

Knee Dislocation

Knee dislocation seldom happens because the joint is reinforced strongly by muscles, tendons, and ligaments. However, when it does happen, it is usually severe and requires immediate medical attention. In knee dislocation, the thigh and leg bones that form the knee joint become misaligned or bent out of place.

This type of injury usually occurs due to high-energy forces such as those resulting from automobile accidents, falls from a height, and high-impact sports.

Knee dislocation is also associated with ligament tear, compression, or damage to important nerves of the leg, and rupture of major blood vessels. If this is not given immediate medical care, it can lead to leg amputation.

Knee Fracture

The knee joint is composed of the knee cap (patella), the thigh bone (femur), the shin bone (tibia), and the smaller calf bone (fibula). Any of these bones can break, resulting in a fracture. Fractures can be non-displaced or displaced and open or closed.

In non-displaced fractures, the broken bones remain in contact, while in displaced fractures, the pieces of the bones become misaligned. Open fractures are those in which a piece of the broken bone pierces the skin, while closed fractures are those in which the skin remains undamaged and broken bones remain inside.

When your knee hits concrete, your knee cap usually comes in contact with the ground and receives most of the impact; thus, this most commonly results in fractured knee bone.

A knee fracture results in pain, swelling, and difficulty bending the knee. Most mild fractures can heal with home treatment; however, you may be required to wear a cast to prevent excessive movement and to make sure that the bones are properly aligned as they heal.

How Do I Know If My Knee Injury Is Serious Enough To Have It Checked Out?

Mild abrasion, laceration, and contusion may be painful or tender when touched but they usually heal on their own and can be managed with home remedies.

However, if you fell or slipped with your knee hitting a concrete and you observe the following symptoms, seek immediate medical attention:

  • If you notice excessive bleeding or if the bleeding does not stop after a few minutes.
  • If after a few days you notice that there is pus leaking from the abrasion or laceration, which can indicate infection.
  • When you hear a popping or cracking sound as you hit the ground, which is usually associated with a ligament tear or a fracture.
  • When there is swelling and the injured knee is warm to the touch, especially if it persists or increases after 2 to 3 days.
  • When you find it hard to put weight on your injured leg.
  • When you stand or walk and your knee feels unstable, like it is buckling or giving out.
  • When you experience severe pain that interferes with your sleep and if the pain does not decrease with pain medications.
  • If your leg looks deformed and the joint looks out of place.

What Is The Best Medicine For Knee Pain?

Give adequate rest to the injured knee. Non-steroidal anti-inflammatory drugs are usually effective in relieving pain and swelling. You may try topical creams or gels that are sprayed or rubbed on the skin to relieve pain. However, these should not be spread directly over abrasions or lacerations.

A cold compress or cold patch can also be used to help relieve pain and swelling, but this should not be applied for more than 20 minutes and is only beneficial during the first two to three days after the injury.

After three days, when the pain and swelling are reduced, you may use a hot compress to prevent stiffness of the joint. A hot compress is beneficial to use before performing exercises to increase the blood flow in the area and facilitate further healing.

Pain is subjective and varies by person; thus, the effect of pain medications depends on the individual and the severity of the injury. 

Aside from taking pain medications, it is important to rest and refrain from moving the injured area to give it time to heal, especially during the first few days after the injury. 

If the pain is severe, does not improve, or worsens after a few days of home management, consult your doctor immediately.  

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