Recurrent Patellar Dislocation

Recurrent patellar dislocation occurs when the kneecap repeatedly moves out of its normal groove, usually toward the outer side of the knee. Some patients experience complete dislocations, while others feel repeated slipping, shifting, or a sense that the kneecap is about to move out of place.

Recurrent instability is different from a single traumatic dislocation. Repeated episodes often indicate that one or more stabilizing structures or anatomical factors are contributing to the problem. Treatment therefore requires evaluation of the entire patellofemoral joint rather than focusing only on the kneecap itself.

What Is Recurrent Patellar Dislocation?

The patella normally glides within a groove at the front of the femur called the trochlea.

Recurrent patellar dislocation means that the kneecap leaves this groove more than once.

In some patients, the patella completely dislocates. In others, it partially shifts outward and then returns to position, which is called patellar subluxation.

Why Does the Patella Dislocate Repeatedly?

Recurrent instability usually develops because several factors interact.

These may include:

• Previous traumatic patellar dislocation
• Injury or insufficiency of the medial patellofemoral ligament
• Trochlear dysplasia
• Patella alta
• Abnormal tibial tubercle position
• Femoral or tibial rotational abnormalities
• Generalized ligamentous laxity
• Lower-limb alignment problems
• Skeletal immaturity
• Family tendency toward patellar instability

What Is Patellar Instability?

Patellar instability describes excessive movement of the kneecap that can range from a feeling of looseness to repeated partial or complete dislocation.

Some patients experience instability only during sports, while others feel apprehension during stairs, squatting, turning, or even everyday movements.

What Is Patellar Subluxation?

Patellar subluxation is a partial displacement of the kneecap.

The patella shifts away from its normal position but does not necessarily remain completely dislocated.

Repeated subluxation can still cause pain, cartilage damage, apprehension, and loss of confidence in the knee.

What Are the Symptoms of Recurrent Patellar Dislocation?

Possible symptoms include:

• Repeated kneecap dislocation
• A feeling that the kneecap slips outward
• Fear of the kneecap dislocating again
• Pain around the front of the knee
• Recurrent knee swelling
• Difficulty running or changing direction
• Pain or instability on stairs
• Difficulty squatting
• Reduced confidence during sport
• Clicking, catching, or locking if cartilage damage is present

What Is Patellar Apprehension?

Patellar apprehension is the sensation that the kneecap is about to dislocate, especially when it is pushed or moves toward the outer side of the knee.

Patients may avoid certain positions or activities because they do not trust the knee.

Apprehension can remain even between complete dislocation episodes.

What Is the Medial Patellofemoral Ligament?

The medial patellofemoral ligament, or MPFL, is an important soft-tissue stabilizer on the inner side of the kneecap.

It helps prevent excessive outward movement of the patella, particularly during the early stages of knee bending.

The MPFL is frequently injured during a lateral patellar dislocation and may remain insufficient in patients with recurrent instability.

Does Every Recurrent Dislocation Come From an MPFL Tear?

No. MPFL insufficiency is important, but recurrent patellar instability is often more complex.

A shallow trochlear groove, high-riding patella, abnormal tibial tubercle position, rotational deformity, or generalized ligament laxity may also contribute.

Treating only the MPFL without recognizing important bony factors may not adequately correct instability in selected patients.

What Is Trochlear Dysplasia?

Trochlear dysplasia means that the groove at the front of the femur is shallower or differently shaped than usual.

A well-formed trochlear groove helps guide and stabilize the patella as the knee bends.

If the groove is shallow or abnormal, the kneecap can have less bony restraint and may dislocate more easily.

What Is Patella Alta?

Patella alta means the kneecap sits relatively high.

A high-riding patella may enter the trochlear groove later during knee flexion, leaving it less constrained during the early phase of bending.

This can contribute to instability in selected patients.

What Is the Tibial Tubercle?

The tibial tubercle is the bony attachment point of the patellar tendon on the upper tibia.

Its relationship to the trochlear groove influences the direction of force acting on the kneecap.

A substantially lateralized tibial tubercle can increase the tendency for the patella to move outward.

What Is the TT-TG Distance?

The tibial tubercle-trochlear groove distance, commonly called the TT-TG distance, is an imaging measurement used to assess the relationship between the tibial tubercle and the trochlear groove.

It can contribute to surgical planning in selected patients with recurrent instability.

The measurement should not be used alone to decide whether surgery is required.

Can Rotational Deformity Cause Patellar Instability?

Yes. Excessive femoral internal rotation or tibial rotational abnormalities can influence the direction of forces acting on the kneecap.

Severe rotational abnormalities may be particularly important when instability continues despite previous treatment.

Rotational alignment is assessed selectively rather than routinely treating every patient as if a rotational deformity is present.

Can Generalized Joint Laxity Contribute?

Yes. Patients with generally flexible or lax joints may have less passive soft-tissue restraint around the patella.

This can increase the tendency for recurrent instability, especially when combined with anatomical risk factors.

Can Repeated Patellar Dislocations Damage Cartilage?

Yes. The patella can impact the femur when it dislocates or relocates, potentially damaging joint cartilage.

Repeated instability can increase the cumulative risk of cartilage injury over time.

This is one reason why recurrent episodes should be evaluated rather than treated as harmless events.

Can Recurrent Patellar Dislocation Cause an Osteochondral Injury?

Yes. A fragment containing cartilage and underlying bone can occasionally break away during a dislocation.

This is called an osteochondral fracture.

A displaced fragment may act as a loose body inside the knee and cause swelling, catching, or locking.

Can Patellar Instability Cause Arthritis?

Recurrent instability and repeated cartilage injury can contribute to patellofemoral degeneration over time.

However, not every patient with recurrent patellar dislocation will develop significant arthritis.

Long-term joint health depends on several factors, including cartilage damage, anatomy, instability frequency, and treatment.

How Is Recurrent Patellar Dislocation Diagnosed?

Evaluation begins with a detailed history of the first dislocation, the number of subsequent episodes, current instability symptoms, and activity limitations.

The examination may include:

• Patellar tracking
• Patellar apprehension testing
• Patellar mobility
• Knee range of motion
• Quadriceps strength
• Generalized ligament laxity
• Lower-limb alignment
• Rotational profile
• Hip and lower-limb control
• Assessment for cartilage or meniscus symptoms

Are X-Rays Important?

X-rays are an important part of evaluating recurrent patellar instability.

They can help assess patellar height, trochlear shape, alignment, previous osteochondral injury, and degenerative changes.

Different views may be used depending on the individual case.

When Is MRI Used?

MRI can evaluate the MPFL, articular cartilage, osteochondral injuries, loose bodies, and other soft-tissue structures.

It can also provide information about trochlear anatomy and patellar alignment.

MRI findings should be interpreted together with physical examination and other imaging measurements.

When Is CT Used?

CT may be useful in selected patients when detailed evaluation of bony anatomy or rotational alignment is required.

It can be particularly useful when significant femoral or tibial rotational deformity is suspected or complex reconstruction is being planned.

Can Recurrent Patellar Dislocation Be Treated Without Surgery?

Yes, in selected patients.

Rehabilitation can improve strength, movement control, and confidence, particularly when instability is relatively mild or surgery is not immediately indicated.

However, repeated complete dislocations despite appropriate rehabilitation may indicate a structural instability problem that cannot be corrected by exercise alone.

Non-Surgical Treatment for Recurrent Patellar Instability

Which Exercises Can Help?

An individualized rehabilitation program may include:

• Quadriceps strengthening
• Hip abductor strengthening
• Hip external rotator strengthening
• Gluteal strengthening
• Calf strengthening
• Squat progression
• Step-up and step-down exercises
• Single-leg balance exercises
• Jump and landing training
• Running progression
• Agility and direction-change training

Can Exercise Permanently Correct Patellar Instability?

Exercise can improve muscular control and function, but it cannot reshape a shallow trochlea, lower a high-riding patella, or correct significant bony rotational deformity.

This distinction is important when recurrent instability is primarily driven by structural anatomy.

Can I Run With Recurrent Patellar Instability?

Running may be possible when the knee is stable during straight-line activity and symptoms are controlled.

Cutting, pivoting, sudden direction changes, and contact sports may pose a greater instability challenge.

Activity should be progressed according to symptoms, control, strength, and recurrence risk.

When Is Surgery Considered?

Surgery may be considered when there are repeated dislocations or persistent functional instability despite appropriate rehabilitation.

Possible reasons for surgical treatment include:

• Multiple complete patellar dislocations
• Persistent patellar apprehension and instability
• Inability to return to desired activities
• Significant MPFL insufficiency
• Important anatomical risk factors
• Osteochondral injury or loose body
• Failure of appropriate non-surgical treatment

Is There One Standard Operation for Recurrent Patellar Dislocation?

No. There is no single operation that is appropriate for every patient.

The surgical plan should address the specific reason the kneecap is unstable.

Some patients may require isolated soft-tissue reconstruction, while others need correction of bony alignment or a combination of procedures.

What Is MPFL Reconstruction?

MPFL reconstruction restores the main medial soft-tissue restraint of the kneecap using a tendon graft.

It is commonly used in patients with recurrent lateral patellar instability when the anatomy is appropriate for this procedure.

The graft is positioned to help prevent excessive outward movement of the patella.

Who May Be Suitable for Isolated MPFL Reconstruction?

Isolated MPFL reconstruction may be considered when recurrent instability is mainly related to medial soft-tissue insufficiency and major bony abnormalities are absent or not clinically significant.

The decision requires assessment of trochlear shape, patellar height, tibial tubercle position, rotational alignment, and cartilage condition.

What Is Tibial Tubercle Osteotomy?

Tibial tubercle osteotomy is a procedure in which the bony attachment of the patellar tendon is repositioned.

The direction of correction depends on the underlying problem.

It may be used in selected skeletally mature patients to improve patellar alignment, reduce excessive lateral pull, or modify patellofemoral loading.

What Is Trochleoplasty?

Trochleoplasty is a specialized procedure designed to reshape an abnormal trochlear groove.

It may be considered in carefully selected patients with severe trochlear dysplasia and recurrent instability.

Trochleoplasty is not necessary for every patient with recurrent patellar dislocation.

Can Rotational Deformity Require Osteotomy?

In selected patients with substantial femoral or tibial rotational deformity, a corrective rotational osteotomy may be considered.

These procedures address bony alignment rather than only stabilizing the kneecap with a ligament reconstruction.

Rotational osteotomy is reserved for carefully evaluated cases and is not part of routine treatment for every dislocation.

Can More Than One Procedure Be Performed?

Yes. Some patients have several important instability factors at the same time.

MPFL reconstruction may be combined with tibial tubercle osteotomy, cartilage treatment, or other corrective procedures when clinically appropriate.

Combining procedures unnecessarily can increase surgical complexity, so each component should have a clear indication.

What Happens If Cartilage Is Damaged?

Cartilage damage may be treated at the same time as patellar stabilization in selected patients.

Treatment depends on the size, location, depth, and condition of the cartilage or osteochondral lesion.

A repairable osteochondral fragment may sometimes be fixed, while other cartilage defects may require different techniques.

Recovery After Patellar Stabilization Surgery

Recovery depends on the exact procedure performed.

Isolated MPFL reconstruction generally follows a different rehabilitation pathway from surgery combined with tibial tubercle osteotomy, trochleoplasty, rotational osteotomy, or cartilage procedures.

Rehabilitation commonly progresses through swelling control, restoration of motion, strengthening, balance, running, jumping, and sport-specific training.

Is a Brace Used After Surgery?

A brace is commonly used after many patellar stabilization procedures.

The permitted range of motion, duration of brace use, and weight-bearing progression depend on the procedure and associated repairs.

When Can You Walk After Surgery?

Walking progression depends on whether the operation involves only soft-tissue reconstruction or also includes a bony procedure.

Patients undergoing osteotomy may require greater protection while bone healing occurs.

Weight-bearing instructions should therefore be individualized.

When Can You Return to Running?

Running is introduced after adequate healing, restoration of knee motion, sufficient strength, and good single-leg control.

A fixed timetable is not appropriate for every surgical technique.

When Can You Return to Sport?

Return to sport should be based on functional recovery rather than time alone.

Assessment may include:

• Full or near-full knee motion
• Minimal swelling
• Quadriceps strength
• Hip and lower-limb strength
• Single-leg control
• Jump and landing tests
• Running and agility ability
• Sport-specific movement
• Absence of significant apprehension
• Psychological readiness

Can the Patella Dislocate Again After Surgery?

Yes. Recurrent instability remains possible even after surgical treatment.

Risk depends on anatomy, surgical technique, healing, rehabilitation, trauma, and whether all major instability factors were appropriately addressed.

What Are the Risks of Patellar Stabilization Surgery?

Possible risks include:

• Infection
• Blood clots
• Knee stiffness
• Persistent pain
• Recurrent instability
• Overconstraint of the patella
• Graft-related problems
• Fracture in selected procedures
• Delayed bone healing after osteotomy
• Hardware irritation
• Need for additional surgery

Can Recurrent Patellar Dislocation Be Treated in Adolescents?

Yes. Recurrent instability is common in adolescents, but treatment must account for remaining growth.

Open growth plates may influence the choice of surgical technique and the placement of tunnels or bone procedures.

Surgical planning in growing patients should therefore be adapted to skeletal maturity.

Recurrent Patellar Dislocation vs Anterior Knee Pain

When Should You See an Orthopedic Specialist?

Evaluation is appropriate if:

• Your kneecap has dislocated more than once
• The kneecap repeatedly shifts or subluxates
• You feel instability during stairs or turning
• You avoid sport because of fear of another dislocation
• Recurrent swelling develops
• There is catching or locking
• Previous rehabilitation has not prevented instability
• You have persistent pain after repeated dislocations

When Is Recurrent Patellar Instability More Urgent?

Prompt assessment is appropriate after a new dislocation when the patella remains out of place, the knee is locked, there is severe swelling, significant trauma, inability to bear weight, or numbness or circulation changes in the lower leg.

These findings may indicate fracture, osteochondral injury, loose body, or another significant knee injury.

Recurrent Patellar Dislocation Treatment in Antalya

Recurrent patellar instability should be evaluated as an individual anatomical and functional problem. MPFL insufficiency may be one component, but trochlear dysplasia, patella alta, tibial tubercle position, rotational alignment, cartilage damage, and generalized ligament laxity may also influence treatment.

Evaluation may include physical examination, standing and patellar X-rays, MRI, and selected CT measurements when detailed bony or rotational assessment is necessary.

Some patients can improve with rehabilitation and patellar stabilization exercises. When repeated dislocations continue, surgery may involve MPFL reconstruction, tibial tubercle osteotomy, trochleoplasty, rotational correction, cartilage treatment, or a combination selected according to the patient's anatomy.

Frequently Asked Questions About Recurrent Patellar Dislocation

What is recurrent patellar dislocation?

It means the kneecap has completely dislocated more than once or repeatedly becomes unstable and shifts out of its normal track.

Why does my kneecap keep dislocating?

Recurrent instability may result from MPFL injury, trochlear dysplasia, patella alta, abnormal tibial tubercle position, rotational alignment problems, ligament laxity, or a combination of these factors.

Can recurrent patellar dislocation improve with exercise?

Rehabilitation can improve strength and movement control, but exercises cannot correct major bony anatomical abnormalities.

What is MPFL reconstruction?

MPFL reconstruction uses a tendon graft to restore an important ligament that helps prevent the patella from moving excessively toward the outside.

Does every patient need MPFL reconstruction?

No. Surgery should be based on the cause of instability. Some patients have bony factors that require a different or combined procedure.

What is trochlear dysplasia?

Trochlear dysplasia is an abnormal shape or shallowness of the groove that normally guides the kneecap.

What is patella alta?

Patella alta means the kneecap sits higher than usual, which may delay its engagement with the trochlear groove and contribute to instability.

Can recurrent dislocations damage cartilage?

Yes. Repeated dislocation or subluxation can damage patellar or trochlear cartilage and occasionally cause an osteochondral fragment.

Can I return to sport after stabilization surgery?

Many patients can return to sport after appropriate healing and rehabilitation, but return should be based on strength, stability, movement quality, functional testing, and confidence.

Can the kneecap dislocate again after surgery?

Yes. Recurrence is still possible, although appropriately selected stabilization surgery aims to reduce instability and improve function.