Definition & Overview
A patellectomy is a surgical procedure used to remove the entire or part of the patella, a small bone located in the front part of the knee, which is also known as the kneecap. It is part of the knee joint, along with the thighbone or femur and the shinbone or tibia.
The patella is located within the quadriceps tendon, which connects the shinbone to the thigh muscles. It serves as the pulley for the quadriceps and plays a key role in knee movements and as such, is prone to overuse and damage. When this occurs, the patient may require medical intervention, such as the surgical removal of the patella, to relieve the symptoms.
Who Should Undergo and Expected Results
A patellectomy can be recommended in the case of the following conditions:
Chondromalacia patellae – This is caused by some damage to the cartilage attached to the back of the patella and commonly occurs together with patellofemoral pain syndrome.
Patellofemoral pain syndrome – This occurs when the patella is slightly misaligned, causing it to move beyond the lower femur. If this happens, the patella may rub against the lower femur, causing pain during knee movement.
Patellar tracking disorder – This condition occurs when the patella moves out of its proper position or alignment every time the leg bends and straightens. It is commonly accompanied by a popping sound and grinding feeling in the kneecap.
Locked patellar dislocation – This is a common injury that can occur when the patellar is forced or has a tendency to move out of its place. It is often caused by trauma or overuse.
Problems affecting the patella are commonly due to:
Overuse of the knees – This is a common problem among athletes, as their repetitive actions during training may eventually put a heavy strain on the kneecap.
Misaligned patella – Some people simply suffer from a structural problem affecting the patella, causing it to function in an abnormal manner that may cause pain. Misaligned patellas are commonly due to some imbalance in the knee and hip muscles.
Weak hip muscles – If a person’s hip muscles are weak, there is a tendency for the thigh bone to turn slightly inwards, causing the patella to veer slightly to one side.
Flat feet – People who have flat feet tend to experience overpronation, in which the foot rolls inwards more than normal. When this happens, the knee is forced to compensate. Due to the frequent strain on the knee, the kneecap may eventually suffer.
Knee injuries – Many sports accidents may cause knee injuries that can affect the patella.
A patellectomy helps relieve the symptoms caused by the above conditions or injuries, and also effectively rules out possible recurrences.
Despite its effectiveness, a patellectomy is no longer considered as a primary treatment for patella-related injuries or disease. Although it has been in use for quite some time, it poses some potentially negative effects on knee function. Thus, nowadays, it is more often used only as the last treatment option.
How is the Procedure Performed?
A patellectomy can be either complete (the entire kneecap is removed) or partial (only a certain part of it is removed).
Prior to the surgery, patients are given detailed instructions to ensure their own safety as well as the success of the procedure. First, they are asked to discontinue their use of any kind of anti-inflammatory medications at least a week before surgery as these medications have a blood thinning effect that may cause increased bleeding during the procedure.
They are also asked to undergo a pre-operative test, which is typically carried out a couple of days before surgery.
During the day of the procedure, the patient is made to lie down on the surgical table and general anesthesia is administered. The surgeon then makes a linear incision in the tendon where the patella is located to access the patella bone. Depending on the type of procedure being carried out (either partial or complete), the bone or a part of it is removed. The procedure leaves the tendon intact and functional, but some of its lasting effects on the overall knee function have made it a controversial medical procedure.
Possible Risks and Complications
Since a patellectomy requires an incision, patients face the common risks of surgical operations, namely:
- Delayed healing
To reduce the above risks, patients should follow pre- and post-surgical instructions very carefully.
A patellectomy is also linked to several long-term and serious problems that may affect the knee, including:
Weak knee extension – This occurs when the movement of the quadriceps muscles loses its natural efficiency due to the absence of the patella. This can make it hard for the patient to completely straighten his leg.
Abnormal laxity – The patella plays a key role in knee movement, which is why removing it may leave the quadriceps tendons more lax than normal.
Risk of femoral joint damage – The patella helps protect the femoral joint, making it likely to become damaged even with minor falls.
Some of the above effects are lasting, making the risks of a patellectomy more significant than its benefits.
More recently, some studies and developments have been made to reduce the long-term risks of the procedure. Some of these include newly developed resurfacing procedures, such as the replacement of the trochlea with a metal object to provide more stability following a patellectomy. Nevertheless, to ensure the long-term safety and stability of patients’ knees, a patellectomy is still only performed when all other options have been ruled out.
Gunal I., Karatosun V. (2001). “Patellectomy: an overview with reconstructive procedures.” Clin. Orthop. Relat. Res. 2001 Aug;(389):74-8. http://www.ncbi.nlm.nih.gov/pubmed/11501826
Michels F., Pouliart N., Oosterlinck D. (2008). “Locked patellar dislocation: a case report.” Journal of Medical Case Reports 2008. http://jmedicalcasereports.biomedcentral.com/articles/10.1186/1752-1947-2-371