5 Common Soft Tissue Knee Injuries

Collisions, sporting mishaps, falls, sudden twisting, and even accidental movements can cause soft tissue injuries in the knee. These injuries range from ligament strains to tears in the knee cartilage, which can cause symptoms including pain, stiffness, and reduced movement in the knee.

Soft tissue knee injuries can take a long time to heal, so they need to be supported throughout the recovery process. Recovery from these injuries is possible with professional advice and treatment, which may include exercises, education, and the use of supportive orthopaedic braces. It’s always a good idea to seek medical attention after an injury, especially if the pain is severe, persistent, or makes it difficult to walk.

The Anatomy Of The Knee

anatomy of knee

The knee is a complex hinge joint, connecting three different bones: the femur, the tibia, and the patella. The tibiofemoral joint (between the femur and tibia) is the main joint in the knee and enables knee flexion and extension, as well as slight rotation. The patellofemoral joint (between the patella and femur) is the smaller but still critically important joint in the knee which is vital for strength of the knee muscles.

The muscles around the knee are powerful to enable movements like running, jumping, and hopping. The quadriceps muscles are responsible for straightening the knee, and the hamstring are responsible for flexing the knee.

As lots of force travels through the knee to enable movements like walking, the knee needs additional support from other soft tissue structures as well. This includes the cruciate ligaments which prevent unwanted forwards and backwards motion of the knee, as well as the collateral ligaments which prevent unwanted side to side movements. The meniscus cartilage cushions the joint, alongside other extracapsular and intracapsular structures.


Common Soft Tissue Injuries In The Knee

Given the high forces a knee withstands on a daily basis, some of the structures in the knee can get easily injured. Commonly this occurs in high-impact sports, but can also occur during simple awkward movements like slipping or twisting suddenly.

The following are five common soft tissues injuries that occur in the knee:

1. ACL/PCL Injury

The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) are intracapsular ligaments, located inside the knee joint. They are the main ligaments that support the knee, and connect the tibia to the femur in a cross-shaped or “cruciate” pattern.

Athletes, particularly in contact sports or sports that require frequent changes of direction, have a higher prevalence of ACL and PCL injuries. This is because the cruciate ligaments are commonly injured when changing direction suddenly, decelerating rapidly, landing awkwardly, or in a direct collision.

Signs and symptoms of an ACL/PCL injury include:

  • Pain
  • Swelling
  • An audible “popping” sound at the moment of injury
  • Stiffness or loss of movement in the knee
  • Discomfort or being unable to walk
  • Instability, or feeling like the knee will collapse

Knee Support After An ACL/PCL Injury

Treatment after an ACL or PCL injury depends on the severity of the injury, which can range from a sprain to a complete tear. A doctor will request a scan (usually an MRI) to confirm the diagnosis before recommending the treatment approach, usually either conservative (non-surgical) or surgical treatment.

Depending on the treatment, a doctor may prescribe a custom-designed knee brace for a short time during the recovery period. This is to minimize movement and promote healing, particularly after any surgery. Physiotherapy is usually introduced to rehabilitate and gradually re-strengthen the knee as well.

2. MCL/LCL Tear

The medial collateral ligament (MCL) and lateral collateral ligament (LCL) have an important role in stabilizing the knee, particularly in a side-to-side direction. Even a mild ligament strain can cause pain and affect leisure or sporting activities. Severe or complete tears can cause long-term pain and disability.

Signs and symptoms of an MCL/LCL injury include:

  • Pain
  • Swelling
  • Tenderness on the outside or inside of the knee
  • Instability, particularly from side to side
  • Reduced mobility
  • Difficulty putting weight through the affected leg

Knee Support After An MCL/LCL Injury

Surgery may be required after an MCL/LCL injury, depending on the severity. A physiotherapist is usually involved in the rehabilitation process to help restore range of motion, strength, and stability after injury. Additionally, a knee brace may be prescribed after an MCL/LCL injury to provide stability and comfort whilst the injury is healing. As instability can affect confidence after a knee injury, a brace can also provide support and promote knee confidence.

3. Meniscus (Knee Cartilage) Tears

The menisci are crescent-shaped structures made of fibrocartilage, which support the knee throughout the entire range of joint motion. The knee has two menisci: the medial (inner knee) meniscus and the lateral (outer knee) meniscus. Together, these menisci reduce friction in the knee and absorb the forces that travel through the knee throughout everyday movements.

The knee menisci can get damaged during rapid twisting movements, particularly when the knee is partly or fully bent. There are different types of meniscal tears, ranging from a bucket handle tear to an oblique tear, which have different recovery approaches and timelines.

Signs and symptoms of a meniscal injury include:

  • Sharp pain, particularly in full extension or flexion
  • Swelling
  • Tenderness across the joint line
  • Difficulty putting weight through the knee
  • Instability or locking
  • Pain when twisting or bending the knee

Knee Support After A Meniscal Injury

A meniscal injury can be successfully managed with exercises and mobility aids, like a knee brace. The angle of the brace can be set to protect the knee whilst it recovers. However, surgery may be required for more severe injuries, or when there are mechanical symptoms like locking or instability.

4. Hyperextension Injury

A hyperextension knee injury occurs when the knee is jarred or forced past the normal range. This can occur when suddenly changing directly or stopping, commonly seen in chasing sports such as football or rugby.

Signs and symptoms of a hyperextension injury include:

  • Pain
  • Bruising or swelling
  • Loss of range, particularly end flexion or extension
  • Difficulty putting weight through the knee

Knee Support After A Hyperextension Injury

Hyperextension injuries usually resolve on their own, unless there has been damage to other structures in the knee. A brace might be useful for a short period to provide stability and comfort whilst recovering and regaining secure movement.

5. Quadriceps Strain

The quadriceps muscles extend the knee, and are important in walking, running, and jumping movements. However, during these activities, it’s possible to strain the quadriceps muscle. This is more commonly seen in power sports like rugby or sprinting due to the high forces required. Quadricep strains are commonly categorized according to severity:

  • Grade 1 strain: mild damage to the quadriceps muscles from being slightly stretched
  • Grade 2 strain: a partial tear in the quadriceps muscles from being overstretched
  • Grade 3 strain: a complete tear in the quadriceps muscles, making it impossible to walk without assistance

Signs and symptoms of a quadriceps injury include:

  • Pain in the front of the thigh
  • Bruising in the affected area
  • Swelling
  • Difficulty keeping the knee straight, particularly when standing
  • For severe injuries, it may not be possible to extend the knee or walk

Knee Support After A Quadriceps Injury

Depending on the grade of the strain, surgery may be required to repair the tissue. For milder injuries, it may be possible to return to sport after a short period of time. Physiotherapy is critical in the recovery process to regain movement and strengthen the quadriceps and surrounding muscles.

Recovery After A Knee Soft Tissue Injury

Mild knee injuries often resolve on their own, however more complex injuries may need a structured rehabilitation plan or surgery. It’s important to consult an experienced health professional after an injury to get an accurate diagnosis and determine the best course of treatment. This may include an orthopaedic brace to help provide comfort and help regain confidence in the knee.