James B. Grimes, MD
mis med pro

Patella Dislocation

The patella (knee cap) is a small bone attached to the quadriceps muscles of the thigh by the quadriceps tendon. The patella slides against the femur bone and forms the patellofemoral joint. The patella is protected by a ligament that secures the kneecap from gliding out and is called as medial patellofemoral ligament (MPFL).

Dislocation of the patella occurs when the patella moves out of the patellofemoral groove (called the trochlea). If the knee cap partially comes out of the groove, it is called a subluxation and if the kneecap completely comes out, it is called as dislocation . Patella dislocation is commonly observed in young athletes between 15 and 20 years and commonly affects women because of the wider pelvis creates lateral pull on the patella.


Some of the causes for patellar dislocation include direct blow or trauma, twisting of the knee while changing the direction, muscle contraction, and congenital defects. It also occurs when the MPFL is torn.


The common symptoms include pain, tenderness, swelling around the knee joint, restricted movement of the knee, numbness below the knee, and discoloration of the area where the injury has occurred.


Your doctor will examine your knee and suggests diagnostic tests such as X-ray, CT scan, and MRI scan to confirm condition and provide treatment.

Conservative Treatment Options

There are non-surgical and surgical ways of treating patellofemoral dislocation.

Non-surgical or conservative treatment includes:

  • PRICE (protection, rest, ice, compression, and elevation)
  • Nonsteroidal anti-inflammatory drugs and analgesics to treat pain and swelling
  • Braces or casts which will immobilize the knee and allows the MPF ligament to heal
  • Footwear to control gait while walking or running and also decreases the pressure on the kneecap.
  • Physical therapy is recommended to help control pain and swelling and helps prevent formation of scar tissue. It includes straightening and strengthening exercises which will improve range of motion

Surgical treatment

Surgical treatment is recommended for those individuals who have recurrent patella dislocation. Some of the surgical options include:

  • Lateral-release – It is done to loosen or release the tight lateral ligaments that pull the kneecap from its groove that increases pressure on the cartilage and causes dislocation. In this procedure, the ligaments that tightly hold the kneecap are divided using an arthroscope
  • Medial patellofemoral ligament reconstruction – In this procedure, the torn MPF ligament is reinforced using a tissue grafting technique. Grafts may come from the tissue bank or may be harvested from the hamstring tendons, located at the back of the knee. The tendon grafts are fixed to the patella using anchors. The grafts are either taken from the same individual (auto graft) or from a donor (allograft).
  • Tibial tubercle realignment or transfer – The tibial tubercle is the bony attachment site of the patella tendon. In this procedure, the tibial tubercle is moved towards the center and is then held by two screws. The screws hold the bone in place and allow faster healing and prevent the patella to slide out of the groove.

After the surgery, your doctor will suggest you to use crutches for few weeks, prescribe medications to control pain and swelling, and recommend physical therapy which will help you to return to your sports activities at the earliest.


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