Common Knee Injuries

Common Knee Injuries

Knee injuries are very common.

In fact, it has been identified as one of the most prevalent reasons people see their doctors. In 2010 alone, approximately 10.4 million patients in the USA visited the doctor because of knee fractures, sprains, dislocations, ligament tears, and other injuries. Since the knee is a complex joint, it is vulnerable to a variety of injuries.

Fortunately, many knee injuries can be treated successfully using conventional measures (rehabilitation exercises, bracing, immobilization, etc.). However, other knee injuries might require surgery.

Anatomy of the Knee

The knee is considered the largest joint in the body. It is made up of 4 primary components—cartilage, ligaments, tendons, and bones.


Three bones meet to form the knee joint—femur (thighbone), tibia (shinbone) and patella (kneecap).

Articular Cartilage

The back of the patella and the ends of both the tibia and the femur are covered with articular cartilage. The slippery substance works by helping the knee bone glide smoothly across each other as the leg is straightened or bent.


The two-wedged shaped pieces of meniscal cartilage situated between the tibia and the femur act as a shock absorber. Unlike the articular cartilage, the meniscus is rubbery and tough and it helps stabilize the joint.


The tendons connect the muscles to the bones. The muscles in the front of the thigh are connected to the patella by the quadriceps tendon. Stretching from the patella to the shinbone is the patellar tendon.


The ligaments connect the bones to the other bones. The four primary ligaments in the knee function like strong ropes that hold the bones together and keep the knees stable.

Collateral ligaments

Collateral ligaments are situated on the sides of the knee. On the inside of the knee is the medial collateral ligament while on the outside is the lateral collateral ligament. They brace the knee against unusual movements and controls the knee’s sideways motion.

Cruciate ligaments

Cruciate ligaments are found inside the knee joint. Cruciate ligaments cross each other to form an “X,” with the posterior cruciate ligament in the back and the anterior cruciate ligament in the front. The back and forth motion of the knee is controlled by the cruciate ligaments.

Prevalent Knee Injuries

The most common knee injuries include dislocations, tears and sprains of the soft tissues, and fractures around the knee. In a lot of cases, the injuries involve more than one structure.

Swelling and pain are two of the most common indicators of a knee injury. The knee may also catch or lock up. Several knee injuries may also result in instability—a feeling that the knee is going to give out.

Kneecap (Patellar) Fractures

Because the kneecap functions as a shield for the knee joint, it can easily be broken. Patellar fractures account for at least 1 per cent of all the fractures and will often require surgery to heal as it is a floating and moving bone. It is common among people who are 20 to 50 years old. Men are twice more likely to get kneecap fractures compared to women.


Patellar fractures can be caused by direct blows (i.e. motor vehicle collisions or falls). It is also possible for the patella to be indirectly fractured. For instance, when the thigh muscles contract so violently, it can pull the patella apart. This often occurs in the elderly with osteoporosis.


Pain and swelling in the front of the knee are two of the most prevalent indicators of patellar fractures.

Additional symptoms can include:

  • Inability to walk
  • Inability to straighten the knee
  • Bruising


Nonsurgical Intervention

Surgery is not required when the pieces of the broken bone have not been displaced. Splints or casts may be utilized to keep the knee straight. It will also help ensure the broken ends are in the proper position as the injury heals. The patient won’t be able to put weight on the affected leg until the injury has healed fully. Recovery may take 6 to 8 weeks (or sometimes longer). Using crutches during the healing period is often recommended.

Surgical Treatment

If the patella has been displaced, surgery is often required. Fractured bones that are displaced may take some time to heal or may not heal at all. If there is no broken skin around the fracture site, the doctor may recommend waiting until the abrasions have healed before performing surgery.

Open fractures, on the other hand, exposes the fracture site to the environment and will require immediate surgery. The type of procedure that will be done will depend on the type of fracture sustained. Most commonly a coil wire is used as a tension band. Prior to the operation, the doctor will explain the procedure as well as any potential complications.

Patellar Tendon Tear

Patellar tendon tears can be partial or complete.

Partial Tears

The tear does not completely disrupt the soft tissue. This can be likened to a rope that is stretched that some of the fibers are frayed but the rope remains intact.

Complete Tears

This kind of tear separates the soft tissue in two pieces. When the patellar tendon is completely torn, it gets separated from the kneecap. Without the attachment, straightening the knee would become impossible.


A very strong force can cause the patellar tendon to tear, as in trying to avoid a trip. Direct impact to the knee’s front secondary to blows or falls can often cause patellar tears. Incorrect landing from a jump may also cause tearing of the patellar tendon.


A tearing or popping sensation is felt during patellar tendon tears. Swelling and pain typically follow. Patients are also no longer able to straighten the knee.

Other likely symptoms include:

  • Bruising
  • Cramping
  • Tenderness
  • Indentation at the bottom of the kneecap
  • Difficulty walking (this is often attributed to the knee buckling or giving out)


Key factors will be taken into account when planning the treatment approach. Some of the primary factors considered include the patient’s age, activity level, and the size and type of tear.

Nonsurgical Intervention

Small and partial tears will often respond favourably to nonsurgical interventions.


The doctor might recommend wearing a brace or knee immobilizer to keep the knee straight while it heals. Crutches might also be needed so putting weight on the affected leg is avoided.

Patients will be required to wear the brace or immobilizer for at least 3 to 6 weeks.

Physical Therapy

Once the swelling and initial pain have settled down, physical therapy can commence. Specific exercises that can help restore the range of motion and strength will be taught.

Surgical Treatment

Some cases will require surgery in order to regain knee function. Surgical repair will be carried out to reattach the torn tendon to the kneecap. While tendon repairs are done on an outpatient basis, some patients stay in the hospital for a night after the operation. Whether or not there is a need to stay overnight will depend on the patient’s medical needs. The surgery might be done with regional (spinal) or general anaesthetic.

Anterior Cruciate Ligament Injuries

Anterior cruciate ligament injuries are common knee ligament injuries. These type of tears are rarely partial and few have the potential to heal on its own. Many who suffer from anterior cruciate ligament injuries are able to return to playing sports without any knee stability issues if they receive the right form of treatment.


Twisting injuries to the knee and pulling or stretching of the ligament (hyperextension) can result in anterior cruciate ligament injuries.


Typical symptoms of the injury can include:

  • Pain and swelling
  • Difficulty walking
  • Unstable feeling in the knee


Nonsurgical Intervention


Wearing a brace might be recommended to keep the affected knee from moving. Crutches might also be suggested to keep the patient from putting weight on the affected knee. This is best instituted in the older sportsman.

Physical Therapy

Once the swelling goes down, specific exercises will be taught to help strengthen the leg muscles and restore function to the knee. Irrespective of whether surgery is performed, this remains the pillar of treatment for everyone.

Surgical Treatment

Surgery is often required in the event of combined injuries resulting in gross instability. For instance, if the knee is dislocated and there are multiple torn ligaments, then surgery is deemed necessary.

Since considered less invasive, arthroscopic surgery is often performed to rebuild the anterior cruciate ligament. Less invasive techniques are now preferred since it helps minimize trauma and pain and has a quicker recovery period.

Close Menu