Patellar Instability or Patellar Dislocation
- May 18, 2022
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What is Patellar Instability or Patellar Dislocation?
The patella, formerly known as the kneecap, is the front bone of the knee, responsible for transmitting the strength of the thigh muscles. In some situations, this bone can move out of its normal location, called patellar instability or patellar dislocation, explains the orthopaedic in Delhi.
If the patellar dislocation occurred for the first time, it is called a primal patellar dislocation. From the second episode, it is called recurrent patellar dislocation.
What are the symptoms of patellar instability?
When a patellar dislocation occurs, there is severe pain and an inability to mobilize the knee. It is possible to see and feel that the patella has moved out of place.
Most of the time, the patella comes back into place on its own almost immediately. Rarely, a doctor needs to put it in place with a knee extension manoeuvre.
After a patellar dislocation, there may be a feeling of insecurity with the knee, even without the patella clearly moving out of place. This sensation is called a patellar seizure. It is a very uncomfortable symptom, which can interfere with normal activities, says the orthopaedic in Dwarka.
How and why does patella dislocation occur?
Patellar dislocation can occur from trauma, such as a blow or twist to the knee, or without trauma, in a common movement of the joint.
Some people have knee features that favor patellar dislocation. Among the main ones are:
- High patella
- The patellar tendon is longer, which makes the patella rest on the knee in a higher position, decreasing the bony socket at the beginning of knee flexion.
- Increased patellar tilt
- Femoral trochlea dysplasia
- The groove on the femur where the patella fits can be shallower than normal, completely flat, or even convex.
- Increase of the “Q” angle
- “Q” angle is formed by the direction of traction of the thigh musculature and the direction of traction of the patellar tendon.
- Patients with valgus knees (knees in, or in “X”)
- Ligament laxity is also more predisposed.
What is the medial patellofemoral ligament?
The medial patellofemoral ligament is the structure that prevents dislocation of the patella. When the patella is displaced, it is injured or loosened.
When the patellar dislocation is treated without surgery, what is expected is that this ligament will heal. In the surgical treatment of patellar dislocation, reconstruction of the medial patellofemoral ligament is performed in most cases, explains the orthopaedic surgeon in Delhi.
Learn more about patellar dislocation treatments below.
How is patellar instability diagnosed?
The diagnosis of patellar instability is made through a careful assessment of the patient’s clinical history and physical examination, complemented with imaging tests.
The main test to be evaluated is magnetic resonance imaging, which shows indirect signs of dislocation, injury to the medial patellofemoral ligament, and the anatomical changes that favor instability. In addition, MRI is essential to look for cartilage lesions. Other tests, such as radiographs in special positions and computed tomography, are useful for evaluating the shape of the knee and predisposing factors, states the orthopaedic in west Delhi.
How is patellar instability treated without surgery? In what situation is he indicated?
In the case of a patient with an episode of patellar dislocation, both non-surgical and surgical treatment are possible. The decision for one or the other must be individualized, after a detailed discussion between the patient and the orthopaedic surgeon in Dwarka.
Non-surgical treatment involves immobilization for a period, followed by rehabilitation focused on exercises to strengthen and control the thigh and hip muscles. The goal of successful non-surgical treatment is the absence of new episodes of dislocation and patellar apprehension, the feeling of discomfort or buckling caused by instability, explains the orthopaedic in Dwarka.
In which cases is surgery indicated?
Situations that indicate treatment with patellar dislocation surgery are:
- Recurrent episodes of dislocation (recurrent patellar dislocation)
- Association with cartilage injuries
- Symptoms of apprehension getting in the way of normal activities
Patients with a single episode of dislocation, although they can be treated without surgery, can also opt for surgical treatment. Surgery has the advantage of a lower chance of re-displacement or seizure symptoms for activities, says the orthopaedic surgeon in west Delhi.
What are patellar instability surgeries like?
According to the orthopaedic surgeon in Delhi, there are several procedures available for patellar instability, which are chosen according to the characteristics of each patient, and there may be a combination of procedures. This concept of individualized treatment is known as à la carte treatment, influenced by the French school.
These are the most common procedures performed for patellar dislocation.
- Reconstruction of the medial patellofemoral ligament
This ligament is the main restrictor of patellar dislocation, and its reconstruction is indicated in almost all cases. It is a graft from the patient’s own tendon to remake the ligament.
- Lateral release (or release)
Release of structures that hold the patella on the side or outside, when there is excess tension. Can be done openly or arthroscopically (video surgery)
- Tibial tuberosity osteotomy
A cut is made in the tibial bone to reposition the point where the patellar tendon attaches. This transfer allows for patellar realignment or patellar height correction.
Correction of the shape of the femoral trochlea, the groove where the patella rests on the femur.
- Treatment of cartilage injuries
When cartilage injuries also exist, these may also need specific treatment.
How is the postoperative period and rehabilitation?
Postoperative care depends on the technique used. They usually involve a period of support with crutches and a knee brace. However, from the beginning, it is already allowed to put the foot on the floor and remove the immobilizer to move the knee in most situations. Rehabilitation includes restoring knee mobility and restoring strength and control of the musculature of the thigh, hip, and trunk.