What Is Patellar Subluxation

What Is Patellar Subluxation?

Patella: A small bone in your lower leg that connects to the knee joint.

Subluxation: An abnormal movement or position of a part of the body. For example, if one toe moves out from under another, it’s called a dislocation. If two bones move apart instead of together, it’s called a displacement.

Symptoms: When the kneecap (kneecap) moves out of place, it causes pain when you walk or run. Your knee may feel tight and swollen because the kneecap is pressing against the inside of your thighbone (femur). Sometimes, there are no symptoms at all.

Causes: There are many possible reasons why a person might have a patella dislocation. These include:

A fall while playing sports.

An injury to the kneecap during childhood. This type of injury usually happens when you’re jumping up and down too hard. You’ll probably hear a pop sound when you land. If so, then you’ve had a sprain (sprain) of the kneecap. Most children recover with rest and ice for 10 days before returning to play sports again.

If you’re an adult and have a sprain, it may be 2 to 3 weeks before you can return to your regular activities.

Playing sports that involve repeated jumping and landing (such as basketball or volleyball). The kneecap may move out of place more easily during these activities because the muscles and tendons around the knee aren’t as strong or flexible as they should be.

Other medical conditions. Muscular dystrophy and osteoporosis are diseases that cause your muscles to weaken. If you have either of these conditions, your kneecaps may move out of place more easily.

Tightness in the muscles and tendons around your knee. These muscles and tendons hold your kneecap in place. You can develop tightness due to an injury or activity (such as sports). This can make your kneecap more likely to move out of place.

Symptoms of an acute (acute) dislocation include a pop or snap sound, immediate swelling and bruising, and pain. These symptoms can occur with any type of dislocation.

Long-term complications of knee dislocations include:

Arthritis in the joint. Arthritis is a disease that causes pain, swelling, and loss of movement in your joints. If you dislocate your patella, you’re more likely to develop arthritis in that joint later in life.

Loss of knee function over time. This can happen if the kneecap dislocates multiple times. Each time the kneecap dislocates, some of the bones and soft tissues around your knee are strained and may become damaged. Over time, these injuries can lead to a decrease in movement and strength in your knee.

Tendonitis. This is an inflammation of the tendon that attaches your kneecap to your shinbone. This condition is common in people who have had multiple knee dislocations. It can cause pain, weakness, and a loss of movement in the joint.

Diagnosis: If your doctor suspects you have a dislocated kneecap, he or she will examine your knee and do an X-ray. The X-ray will show whether or not your kneecap is out of place. Your doctor will examine the ligaments that hold your knee together. These ligaments may be torn if you have a dislocation.

Treatment: A dislocated kneecap can be treated in several ways, depending on how severe the injury is and your age. Younger children who have a dislocated kneecap should see an orthopedist (bone doctor). The bone doctor will make sure the kneecap is back in place and then treat any injuries. The ligaments around the knee joint may need to be treated with a splint or cast for several weeks to help them mend. After that time, physical therapy is an excellent way to strengthen the muscles around your knee and prevent a recurrence of a dislocated kneecap.

A dislocated kneecap in an adult is treated more like a broken bone. The orthopedist will reposition the kneecap back into its normal place. Ice and a splint are used to reduce swelling and control pain. In some cases, surgery is needed to repair torn ligaments around the knee. If the knee dislocates frequently or if arthritis is present, surgery may be needed to tighten the ligaments around your knee.

Prevention: To prevent a dislocated kneecap, avoid any activity that risks straining the muscles or tendons around your knee. This includes running and jumping. You may want to wear an athletic support (knee strap) for extra support if you know you’ll be doing activities that could strain your knees, such as downhill skiing.

Sources & references used in this article:

The abnormal lateral patellofemoral angle: a diagnostic roentgenographic sign of recurrent patellar subluxation. by CA Laurin, HP Levesque, R Dussault… – The Journal of bone …, 1978 – europepmc.org

Subluxation of the patella. Computed tomography analysis of patellofemoral congruence. by M Inoue, K Shino, H Hirose, S Horibe… – The Journal of bone and …, 1988 – europepmc.org

Proximal and Distal Reconstruction of the Extensor Mechanism for Patellar Subluxation. by JC HUGHSTON, WM WALSH – Clinical Orthopaedics and Related …, 1979 – journals.lww.com

Patterns of knee arthrosis and patellar subluxation. by MM Harrison, TD Cooke, SB Fisher… – … and related research, 1994 – europepmc.org

Lateral release and proximal realignment for patellar subluxation and dislocation. A long-term follow-up. by G Scuderi, F Cuomo, WN Scott – The Journal of bone and joint …, 1988 – europepmc.org

Chondromalacia induced by patellar subluxation in the rabbit by BN Møller, F Møller-larsen, LH Frich – Acta Orthopaedica …, 1989 – Taylor & Francis

Effect of a patellar realignment brace on patients with patellar subluxation and dislocation by C Muhle, G Brinkmann, A Skaf… – … American journal of …, 1999 – journals.sagepub.com

Electromyography of the Quadriceps in Patellofemoral Pain with Patellar Subluxation. by KJ Mohr, RS Kvitne, MM Pink, B Fideler… – … and Related Research …, 2003 – journals.lww.com