Patellar dysfunction

Patellar dysfunction

Patellar stability is provided by a combination of bony, ligamentous and muscular structures.
In cases of patellar dysfunction, such as a patellar dislocation, a variety of treatment approaches may be considered, ranging from rehabilitation and immobilization to surgical procedures to realign and stabilize the patella.
Patellar realignment surgery includes techniques such as MPFL reconstruction, tibial tuberosity realignment, and other procedures aimed at restoring normal knee function.

Patellar dysfunction

Stability
The extensor apparatus
MPFL
Patella dislocation

How is patellar stability ensured?

The stability of the kneecap (or patella) is ensured by a combination of anatomical and dynamic factors:

Anatomical Factors:

Bony Structures: The femoral trochlea (groove on the surface of the femur) guides the patella during flexion and extension movements of the knee.
Ligaments: The medial patellofemoral ligament (MPFL), patellotibial ligaments, and other ligamentous structures help hold the kneecap in place.

Dynamic Factors:

Muscles: The quadriceps, primarily the vastus medialis oblique (VMO), exerts a medial force to stabilize the patella.
Tendons: The quadriceps and patellar tendons are essential for joint movement and for keeping the kneecap aligned.

What is the extensor device?

Shock Absorption
The menisci absorb and distribute forces and loads applied to the knee during walking, running, and other activities, reducing direct impact on the articular surfaces of the femur and tibia.

Joint stability
They contribute to knee stability by increasing the congruence between the articular surfaces of the femur and tibia, limiting excessive movements that could damage the joint.

Joint Lubrication and Nutrition
The menisci promote the distribution of synovial fluid throughout the knee joint, which helps lubricate and nourish the articular cartilage, essential for healthy joint function.

Load Distribution
They help to evenly distribute the load across the knee joint, reducing pressure on specific areas and minimizing wear and tear on the joint cartilage.

Proprioception
The menisci contain sensory receptors that provide information about the position and movement of the knee, contributing to proprioception, which is the body's ability to sense joint position.

What is MPFL?

The Medial Patellofemoral Ligament (MPFL) is a ligamentous structure that connects the kneecap (patella) to the medial portion of the femur (thigh bone).
It plays a crucial role in preventing lateral dislocation of the patella, particularly between 0 and 30 degrees of knee flexion.
It is often damaged during patellar dislocation.

What is Patellar Dislocation?

Patellar Luxation occurs when the kneecap moves from its normal position in the femoral trochlea, usually outward (lateral dislocation). It can occur due to:

Trauma: Direct impact or twisting of the knee.
Anatomical Abnormalities: Trochlear dysplasia, excessive rotation of the femur or tibia, or poor insertion of the patellar tendon.
Ligamentous Laxity: Weakening of the ligaments that hold the kneecap in place.
How can a dislocated kneecap be treated?
Treatment of patellar dislocation may be nonsurgical or surgical, depending on the severity and frequency of the dislocations.

Non-Surgical Treatments:

Closed Reduction: Patella repositioning technique.
Immobilization: Use of a splint or cast to stabilize the knee while it heals.
Physiotherapy: Strengthening of the quadriceps muscles, particularly the vastus medialis oblique (VMO), to improve patellar stability.

Surgical Treatments:

MPFL Reconstruction: Replacement or reinforcement of the MPFL.
Soft Tissue Realignment: Surgery to adjust the tissue structures around the kneecap.
Osteotomies: Bone realignment to correct anatomical abnormalities.
What is patellar re-centering surgery?
Patellar re-centering surgery aims to realign and stabilize the kneecap to prevent recurrent dislocations.

MPFL Reconstruction
Realignment
Osteotomy

Reconstruction of the MPFL:

 

 

Medial patellofemoral ligament (MPFL) reconstruction is a surgical procedure to restore stability to the kneecap (patella) by replacing or strengthening the MPFL ligament.
This ligament is crucial for maintaining the patella in alignment, especially during the first few degrees of knee flexion. Reconstruction is often necessary after repeated episodes of patellar dislocation or severe MPFL injury.

Indications for MPFL Reconstruction
Repeated Patellar Dislocations: Repeated dislocations or chronic instability of the patella.
MPFL failure: Significant injury or weakening of the ligament following an acute dislocation.
Anatomical Abnormalities: Malformations of the femoral trochlea or misalignment of the patella increasing the risk of dislocation.

Preparation for Surgery
Medical Assessment:

Consultation with an orthopedist specializing in knee pathologies.
Complete assessment of the knee joint, including MRI to assess the condition of the MPFL and surrounding structures.

Surgical Planning:

Choice of graft (often a hamstring tendon or an allograft).
Assessment of the patient's specific needs and planning of anatomical corrections if necessary.

Anesthesia:

MPFL reconstruction is performed under regional or general anesthesia.

Surgical Procedure

Incisions:

Small incisions are made to insert the arthroscope and surgical instruments.

Preparation of the graft:

The graft is prepared using either autologous tendon (e.g., hamstring tendon) or allograft.

Fixing the graft:

Medial Insertion Point: The graft is fixed to the medial part of the patella.
Femoral Insertion Point: The graft is then delivered and secured to a specific point on the medial femur, often with screws or anchors.

Tension and Verification:

The tension of the graft is adjusted to ensure optimal stability of the patella.
Checking patella mobility and alignment by flexion and extension of the knee.

Closing the Incisions:

The incisions are closed with sutures or adhesive strips.
The joint is cleaned and irrigated to remove debris.

Postoperative and Rehabilitation
Wake up and Return Home:

Most patients are able to return home the same day or after a short hospital stay.
Follow the post-operative instructions given by the surgeon.

Pain and Swelling Management:

Pain medications prescribed to manage post-operative discomfort.
Apply ice and elevate the knee to reduce swelling.

Immobilization and Rehabilitation:

A splint or brace may be used to immobilize the knee for the first few weeks.

Physiotherapy Program:

Gentle mobility exercises to prevent joint stiffness.
Progressive exercises to strengthen the quadriceps muscles and other muscles around the knee.
Proprioception and balance exercises to improve knee stability.

Back to Activities:

The return to daily and sporting activities is gradual, based on individual recovery.
Patients can usually return to light activities within a few weeks and more intense sports activities within 4 to 6 months, depending on medical advice.
Expected Results and Potential Complications

Positive Results:

Significant improvement in patella stability.
Reduction of dislocation episodes.
Improved knee function and reduced pain.

Potential Complications:

Risk of infection, although rare.
Deep vein thrombosis (DVT).
Graft failure or loss of fixation requiring reintervention.
Joint stiffness or temporary loss of mobility.

MPFL reconstruction is a surgical procedure to restore stability to the patella by replacing or strengthening the MPFL ligament.
It is particularly indicated in patients with recurrent patellar dislocations or chronic patellar instability. Adequate preparation, precise surgical execution and rigorous postoperative rehabilitation are essential to optimize results and minimize complications.

Soft Tissue Realignment

Soft tissue realignment is a surgical technique used to treat patellar instability by adjusting the tissue structures around the kneecap.
This procedure aims to correct muscular and ligament imbalances that can lead to dislocation or subluxation of the patella.

Goals of Soft Tissue Realignment

Correct Excessive Lateral Pull: Reduce the lateral pulling force that pulls the kneecap out of its normal position.
Strengthen Medial Support: Improve support of medial structures to stabilize the patella.

Indications for Soft Tissue Realignment
Repeated Patellar Dislocations: Frequent dislocations or subluxations of the kneecap.
Muscle Imbalance: Imbalance between the muscles that pull the kneecap outward and those that keep it in a central position.
Medial Structure Insufficiency: Weakness or damage to medial structures such as the medial patellofemoral ligament (MPFL).

Soft Tissue Realignment Procedure
Soft tissue realignment surgery involves several techniques that can be used alone or in combination to stabilize the patella.

Lateral Release:

Purpose: To release the tissues on the lateral side of the patella to reduce excessive traction.
Technique: Section or lengthening of the lateral retinaculum, a band of connective tissue that can pull the kneecap outward.
Medial Imbrication:

Purpose: To strengthen the tissues on the medial side of the kneecap to improve support.
Technique: Plication or tightening of the medial tissues, including the MPFL if necessary, to stabilize the patella.
MPFL Repair:

Purpose: To repair or reconstruct the MPFL to prevent lateral dislocation.
Technique: Use of a tendon graft to replace or reinforce the MPFL.
Muscle strengthening:

Purpose: To improve the strength of the quadriceps muscles, particularly the vastus medialis oblique (VMO).
Technique: Postoperative rehabilitation program to strengthen the quadriceps muscles and improve muscle control of the patella.

 

Postoperative and Rehabilitation
Pain and Swelling Management:

Painkillers and anti-inflammatory medications.
Ice application and knee elevation.

Immobilization and Early Mobilization:

Use of a splint or brace to immobilize the knee during initial healing.
Early mobilization under supervision to avoid joint stiffness.

Physiotherapy:

Muscle strengthening exercises for the quadriceps and hip muscles.
Proprioception and balance exercises to improve knee stability.
Progressive rehabilitation program to restore knee function and mobility.
Expected Results and Potential Complications

Positive Results:

Significant reduction in episodes of dislocation or subluxation.
Improved patella stability and overall knee function.
Decreased pain and symptoms associated with patellar instability.

Potential Complications:

Surgical infection.
Hematoma or bleeding.
Joint stiffness or temporary loss of mobility.
Insufficient correction requiring additional surgical intervention.

Soft tissue realignment is a surgical procedure to correct muscle and ligament imbalances that cause patellar instability.
By adjusting the tissue structures around the patella, this technique can improve knee stability, reduce dislocation episodes, and improve joint function.
The success of the procedure depends on accurate assessment, proper surgical execution, and rigorous postoperative rehabilitation.

Osteotomy

An osteotomy is a surgical procedure that involves cutting and realigning a bone to correct structural abnormalities. In the context of patellar dysfunction, the main purpose of osteotomy is to reposition the patella and improve knee mechanics, particularly to treat patellar instability or patellofemoral pain syndrome.

Goals of Osteotomy for Patellar Dysfunction
Reduce Lateral Pull: Correct the tendency of the patella to dislocate or sublux outward.
Improve Patella Alignment: Ensure the patella aligns properly within the femoral trochlea during knee movements.
Reduce Pain: Relieve pain associated with patellar misalignment and patellofemoral pain syndrome.

Types of Osteotomy
The two most commonly used types of osteotomy for patellar dysfunction are:

Anterior Tibial Tuberculosis (AT) Osteotomy:

Objective: To reposition the patellar tendon attachment to realign the patella.
Technique: Medial or anteromedial displacement of the tibial tuberosity.

Femoral Osteotomy:

Objective: To correct excessive rotation or angulation of the femur that contributes to patellar misalignment.
Technique: Make a cut in the femur and reposition the bone segments to correct the alignment.

Preparation for Surgery
Preoperative Assessment:

Complete clinical examination of the knee.
Medical imaging (X-rays, MRI, CT scan) to plan surgery.
Discussions with the patient regarding expectations and potential outcomes.

Surgical Planning:

Choosing the appropriate osteotomy technique.
Measuring angles and distances to be corrected.
Surgical Procedure

Anesthesia:

The surgery is performed under general or spinal anesthesia.
Incision:

An incision is made on the anterior part of the knee to access the tibial tuberosity or femur.

Bone Resection:

For an anterior tibial tuberosity osteotomy:
The tibial tuberosity is partially cut and displaced medially or anteromedially.

For a femoral osteotomy:
A cut is made in the femur to allow realignment of the bone segments.

Fixing:

The displaced bone segments are fixed using screws, metal plates or other fixation devices.
The fixing is checked to ensure stability and proper alignment.

Closing the Incision:

The incisions are closed with sutures or staples.
A splint or bandage is applied to protect the surgical site.

Postoperative and Rehabilitation

Pain and Swelling Management:

Painkillers and anti-inflammatory medications.
Ice application and leg elevation.

Immobilization :

Use of a splint or brace to limit movement and protect the osteotomy.

Physiotherapy:

Begin gentle mobilization exercises as soon as possible to avoid joint stiffness.
Progressive strengthening of the quadriceps muscles and hip muscles.
Proprioception and balance exercises to improve knee stability.

Medical monitoring:

Regular visits to the surgeon to monitor bone healing.
Control X-rays to check for proper alignment and bone consolidation.
Expected Results and Potential Complications

Positive Results:

Improved patellar alignment.
Reduction of dislocation or subluxation episodes.
Decreased pain and improved knee function.

 

Potential Complications:

Risk of infection.
Bone healing problems.
Joint stiffness.
Deep vein thrombosis.
Reoperation required in case of misalignment or fixation complications.
Conclusion
Osteotomy is an effective procedure to treat patellar dysfunction by correcting structural abnormalities that contribute to patellar instability and patellofemoral pain. Careful planning, precise surgical technique, and rigorous postoperative rehabilitation are essential to achieve optimal results and minimize complications.