One day, while walking up the stairs to catch the subway, I was suddenly reminded of the importance of taking care of my knees, as a small anecdote with a subtle cracking sensation brought home the reality of chondromalacia patella.

Introduction

Chondromalacia patellae, often called patellofemoral syndrome, is a medical condition characterized by softening or wearing away of the cartilage located under the kneecap of the knee. This condition mainly affects the joint area between the kneecap and the femur. Chondromalacia patellae often occurs in young adults, especially teenagers and people in their 20s, although cases can also be seen in older individuals.

The main contributing factor to chondromalacia patella is abnormal pressure placed on the cartilage of the patella, usually due to abnormalities in the mechanics of the knee. When the patella does not move properly along the groove of the femur during knee movements, it can cause uneven distribution of pressure on the cartilage, causing it to soften.

Common symptoms of chondromalacia patellae include localized pain in the front of the knee, often exacerbated by activities such as going up or down stairs, sitting for long periods of time, or squatting. Pain may also be felt when participating in sporting activities, especially those involving repetitive knee movements.

Diagnosis of chondromalacia patellae is often based on clinical evaluation, a thorough medical history, and imaging tests such as X-rays and MRIs. These tests make it possible to assess the condition of the cartilage under the kneecap and determine the severity of the disease.

The management of patellar chondromalacia is based on several approaches. Initially, conservative measures such as rest, ice application, knee elevation, and anti-inflammatories may be recommended to relieve pain and reduce inflammation. Osteopathy is also often prescribed to strengthen surrounding muscles, improve knee stability, and correct muscle imbalances that may contribute to the condition.

In more severe or persistent cases, surgical interventions may be considered. These may include procedures such as debridement surgery, where fragments of damaged cartilage are removed, or performing realignment surgery to correct joint mechanics.

It is essential to emphasize that the management of chondromalacia patellae must be personalized according to the severity of symptoms and the response to different interventions. Regular follow-up with a healthcare professional is necessary to adjust the treatment plan as the patient progresses in recovery. Additionally, preventing overuse of the knee and adopting proper techniques during physical activities can play a crucial role in the long-term management of this condition.

Biomechanics

Chondromalacia patellae, when examined from a biomechanical perspective, reveals complex interactions between the joint structures of the knee, mainly the patella and the femur. Joint biomechanics play a crucial role in the development of this condition, involving specific forces, movements and pressures that impact the cartilage beneath the kneecap.

The biomechanical mechanism of patellar chondromalacia often begins with abnormalities in the natural trajectory of the patella during knee movements. Normally, the patella slides smoothly along the groove of the femur during knee flexion and extension. However, muscular imbalances or anatomical factors can disrupt this trajectory, generating uneven pressure on the cartilage.

A muscular imbalance, where certain muscle groups are weaker or tighter than others, can change the path of the kneecap. For example, weakness in the quadriceps muscles can allow the kneecap to deviate from its normal path, causing uneven distribution of pressure on the cartilage. This abnormal pressure can cause it to soften and wear out.

The biomechanics of chondromalacia patellae may also be influenced by anatomical factors, such as the shape of the patella or the slope of the femur. A flatter patella or different femoral slope can create uneven forces during knee movements, contributing to cartilage breakdown.

Physical activities, especially those involving repetitive knee movements, can exacerbate the effects of altered biomechanics. Activities like running, jumping, or playing certain sports can increase pressure on the kneecap and speed up the cartilage softening process.

Accurately diagnosing patellar chondromalacia from a biomechanical perspective often involves advanced imaging studies, such as MRI, to assess the trajectory of the patella, the condition of the cartilage, and possible anatomic abnormalities. Understanding these biomechanical aspects is essential to developing an effective treatment plan.

The biomechanical management of chondromalacia patellae relies on correcting muscular imbalances and improving joint stability. Physiotherapy plays a central role in strengthening the knee muscles, restoring muscular balance and correcting biomechanical deficiencies. Specific rehabilitation techniques can be applied to realign the trajectory of the patella and minimize uneven forces on the cartilage.

Underlying mechanism

  1. Excessive pressure on the kneecap: Chondromalacia patellae is often the result of excessive pressure on the kneecap during knee movements. This can result from a variety of factors such as poor alignment of the kneecap, weakening of the quadriceps muscles, joint instability, or repeated trauma.
  2. Cartilage degeneration: Excessive pressure and abnormal movements can lead to degeneration of the cartilage of the patella. Initially, the cartilage may become softened and lose its normal resilience, then it may crack and deteriorate over time.
  3. Inflammation and inflammatory response: Cartilage degeneration can trigger an inflammatory response in the knee joint. The resulting inflammation can cause pain, swelling and stiffness.
  4. Alteration of the function of the patella: The damaged cartilage no longer effectively fulfills its role as a shock absorber between the patella and the femur. This can cause the normal function of the patella to be impaired during knee movements.
  5. Progression to more advanced stages: Without adequate treatment, chondromalacia patellae can progress to more advanced stages, involving more serious damage to the cartilage or even exposure of the underlying bone.

Anatomy of the Knee: The Structure of the Patella and Its Role

The anatomy of the knee is complex, involving a sophisticated interconnection of ligaments, tendons, muscles and bones. At the heart of this structure, the patella, or patella, is a triangle-shaped bone located at the front of the knee. Its crucial role in knee biomechanics makes it a key element in joint stability and the transmission of forces during movement.

The patella plays a vital role in improving knee mechanics, acting as a lever for the quadriceps muscles. These muscles attach to the patella via the quadriceps tendon, and by exerting traction on the patella, they facilitate knee extension. This action helps stabilize the patella during movement, ensuring optimal alignment along the groove of the femur.

The structure of the patella includes several important parts. The posterior surface of the patella is covered with articular cartilage, which provides smooth articulation with the femur during flexion and extension of the knee. This cartilage is essential for minimizing friction and evenly distributing forces across the joint surface.

The patella is also surrounded by the patellar tendon, which connects the patella to the tibial tubercle. This tendon, often used during jumping or activities requiring rapid knee extension, is crucial for knee stability and function.

In terms of its functional role, the patella acts as a lever mechanism that increases the mechanical efficiency of the quadriceps during knee extension. As the knee extends, the patella moves into the groove of the femur, facilitating movement and reducing pressure on the quadriceps tendon.

However, this anatomical complexity makes the patella susceptible to various conditions, including the previously mentioned patellar chondromalacia. Abnormalities in the trajectory of the patella, muscular imbalances, or anatomical factors can lead to uneven pressure on the cartilage, causing it to soften and break down.

Diagnosing and managing problems related to the patella requires a thorough understanding of its anatomy and function. Imaging tests, such as X-rays or MRIs, are often used to evaluate the condition of the patella, detect possible abnormalities and guide the treatment plan.

Patellofemoral joint

The patellofemoral joint, playing a crucial role, performs two main functions: acting as an anatomical pulley to provide mechanical advantage to the extensors and reducing friction between the extensor mechanism and the femur. The patella, having the shape of an inverted triangle, fits harmoniously into the quadriceps tendon, thus giving it the status of the largest sesamoid bone in the body. Distally, it attaches to the tibial tubercle via the patellar tendon.

The posterior articular surface of the patella is divided into two distinct facets, medial and lateral, separated by a vertical ridge. In 30% of the population, a third facet, the odd facet, the most medial, completes this unique configuration.

The patella engages with the trochlear groove of the anterior femur, presenting corresponding articular surfaces: patellar, lateral and medial. It should be noted that the lateral trochlear articular surface is generally distinguished by a greater prominence than its medial part. During movements of the knee joint, from extension to flexion, the articular surface of the patella comes into contact with the variations of the femur.

When fully extended, the patella has little or no contact with the trochlear groove, potentially placing it in an unstable position. Between 10 and 20 degrees of flexion, the patella engages the trochlear groove, with the contact area being the lowest portion of the medial and lateral facets. As the knee progresses into greater flexion, the contact surface moves more proximally on the patella. Only beyond 90 degrees of flexion does the odd facet come into contact with the medial femoral condyle, thereby contributing to load sharing with the lateral facet. Additionally, in this degree of flexion, the quadriceps tendon itself engages in the proximal trochlear groove, actively participating in force distribution.

Causes Patellar Chondromalacia

Chondromalacia patellae, often referred to as patellofemoral syndrome, has its origins in a variety of factors, and understanding its causes is crucial for diagnosis and implementation of an appropriate treatment plan. This joint condition, characterized by the softening of the cartilage located under the kneecap, can be influenced by anatomical, mechanical, muscular and even lifestyle elements.

One of the major factors contributing to chondromalacia patella is misalignment of the kneecap during knee movements. An abnormal trajectory of the patella can cause uneven pressure on the cartilage, thus promoting its softening. Anatomical abnormalities, such as a flat patella or a specific femoral slope, may predispose to this misalignment and contribute to the development of chondromalacia.

Muscle imbalances also play a crucial role. The quadriceps muscles, which attach to the kneecap via the quadriceps tendon, are essential for maintaining optimal trajectory. Any weakening or imbalance in these muscles can compromise the stability of the patella, increasing the risk of chondromalacia.

Repetitive trauma or microtrauma, often related to strenuous physical activities or repetitive movements of the knee, can also contribute to the development of chondromalacia patella. These repeated stresses on the kneecap and its cartilage can gradually lead to its softening and wear.

Lifestyle factors should not be neglected. Being overweight, for example, puts increased pressure on joints, including the kneecap, which can contribute to the development of chondromalacia. Likewise, poorly adapted physical activities, a lack of muscular flexibility, or inappropriate shoes can negatively influence the biomechanics of the knee.

People with chronic joint instability or congenital knee defects may also be more likely to develop chondromalacia patella. Genetic factors may thus play a role in predisposition to this condition.

Accurately diagnosing the causes of chondromalacia patellae often involves imaging tests, such as X-rays or MRIs, to evaluate the condition of the cartilage and identify possible structural abnormalities. A thorough assessment of medical history, physical activities, and lifestyle is also essential to determine contributing factors.

The management of patellar chondromalacia is based on the correction of muscular imbalances, the rehabilitation of the trajectory of the patella, and the management of modifiable risk factors, such as being overweight. Physiotherapy plays a central role in these approaches, aiming to strengthen muscles, improve joint stability, and teach proper movement techniques.

  1. Poor Knee Alignment: Poor knee alignment, such as bow legs (genu varum) or .
  2. Trauma: Knee injuries, such as sprains, fractures, or dislocations, can damage the cartilage and contribute to the development of chondromalacia patella.
  3. Knee Instability: Chronic instability of the knee, often due to ligament damage, can cause abnormal distribution of pressure on the kneecap, leading to wear of the cartilage.
  4. Overuse or High-Impact Activities: Regular participation in high-impact activities, such as running or jumping sports, can contribute to wear and tear on the cartilage of the patella, especially if combined with poor technique or to overuse.
  5. Muscular Dysfunction: A muscular imbalance between the quadriceps and hamstring muscles can lead to poor stabilization of the knee, thus promoting the development of chondromalacia.
  6. Congenital Anatomical Factors: Some individuals may have congenital anatomical abnormalities, such as a poorly positioned patella, that increase their predisposition to patellar chondromalacia.
  7. Age: Although chondromalacia patellae can affect individuals of any age, it is often associated with age-related degenerative changes, particularly in older individuals.
  8. Gender: Women appear to be more likely to develop chondromalacia patella than men, which may be attributed to differences in knee biomechanics and hormonal fluctuations.
  9. Joint Inflammation: Inflammatory conditions such as arthritis can contribute to the deterioration of the cartilage in the kneecap.

Chondromalacia patellae can result from a combination of several of these factors.

Symptoms

The symptoms of chondromalacia patellae are varied and can affect the quality of life of affected individuals. This joint condition, characterized by softening of the cartilage under the kneecap, generally manifests itself with specific signs related to knee mobility, causing a range of noticeable symptoms.

Pain is one of the predominant symptoms of chondromalacia patellae. This pain is often located in the front of the knee, behind the kneecap, and can be felt diffusely or concentrated. The pain may be exacerbated by specific activities, such as going up or down stairs, sitting for long periods of time, or squatting. It can also be triggered by repetitive knee movements, such as running or jumping.

A cracking or crackling sensation may accompany the pain in some people with chondromalacia patella. This sound often results from abnormal friction between the kneecap and femur due to softened cartilage. Crepitus can be seen as an audible symptom or felt by the patient during knee movements.

Chondromalacia patellae can also manifest as knee instability. Affected individuals may experience a “giving” sensation or weakness in the knee, which may compromise their ability to perform physical activities without discomfort. This instability can be associated with muscular imbalances which disrupt the normal trajectory of the patella.

Knee swelling is a common symptom of chondromalacia patella. Inflammation often results from irritation of damaged cartilage, leading to an inflammatory response in the joint area. Swelling can contribute to knee stiffness, limiting its range of motion and making pain worse.

  1. Kneecap Pain: Pain is often felt directly below the kneecap, especially during activities such as going up or down stairs, running, or after prolonged sitting.
  2. Crepitation: Some individuals may experience a crepitating or rubbing sensation when moving the kneecap, usually associated with cartilage deterioration.
  3. Knee Flexion Pain: Pain may increase when bending the knee, especially when the knee is bent for a long time.
  4. Pain While Sitting: Some people experience pain after sitting for a prolonged period of time, which can put additional pressure on the kneecap.
  5. Swelling: Mild swelling or a feeling of warmth can sometimes accompany chondromalacia patella, especially if there is inflammation.
  6. Muscle Weakness: Weakness in the muscles around the knee, particularly the quadriceps, may develop due to avoidance of activities that cause pain.
  7. Difficulty Bending or Extending the Knee: Some individuals may have difficulty fully bending or extending the knee due to pain or stiffness associated with chondromalacia.

Risk factors

Several risk factors can contribute to the development of chondromalacia patella. Here are some of these factors:

  1. Knee Trauma or Injury: Previous injuries to the knee, such as sprains, fractures or dislocations, can damage the cartilage under the kneecap, leading to chondromalacia.
  2. Knee Instability: Chronic instability of the knee, often due to ligament damage, can lead to abnormal distribution of pressure on the cartilage and contribute to the development of chondromalacia.
  3. Poor Knee Alignment: Anatomical problems such as bow legs (genu varum) or X-legs (genu valgum) can lead to improper distribution of pressure on the cartilage, increasing the risk of chondromalacia.
  4. Overuse: Excessive use or strenuous physical activities, especially those that involve repetitive movements of the knee, can contribute to premature wear of cartilage.
  5. Muscle Dysfunction: A muscular imbalance around the knee, particularly between the quadriceps muscles and the hamstring muscles, can lead to poor knee stability, increasing the risk of chondromalacia.
  6. Anatomical Factors: Some individuals may have congenital anatomical abnormalities that increase their predisposition to chondromalacia patella.
  7. Age: Although chondromalacia patellae can occur at any age, it is often associated with age-related degenerative changes.
  8. Gender: Women appear to be more likely to develop chondromalacia patella than men, which may be related to differences in knee biomechanics.
  9. High Impact Activities: Participating in high impact activities, such as running on hard surfaces, can increase stress on cartilage and contribute to the development of chondromalacia.

It is important to note that chondromalacia patellae can result from a combination of several of these risk factors.

Differential diagnosis

  1. Osteoarthritis of the knee: Chondromalacia patellae and osteoarthritis of the knee share symptoms such as pain and stiffness, but they affect different parts of the knee. Osteoarthritis involves wear and tear of articular cartilage throughout the joint, while patellar chondromalacia focuses specifically on the kneecap.
  2. Patellar tendonitis: Inflammation of the patellar tendon can cause similar symptoms, such as pain with physical activity and knee flexion.
  3. Iliotibial band syndrome: This condition involves inflammation of the iliotibial band, often causing pain on the outside of the knee. It can be confused with chondromalacia patellae due to similar symptoms.
  4. Prepatellar bursitis: Inflammation of the prepatellar bursa can cause pain in the front of the knee, similar to that of chondromalacia patella.
  5. Meniscal lesions: Meniscal lesions can cause pain and discomfort similar to chondromalacia patella. A thorough assessment is necessary to differentiate between these conditions.
  6. Patellofemoral Syndrome: This condition, also known as “patellofemoral pain syndrome,” shares similarities with chondromalacia patella in terms of anterior knee pain.
  7. Ligament Injuries: Ligament injuries, such as anterior cruciate ligament (ACL) or medial collateral ligament (MCL) sprains, can cause similar symptoms, including knee pain and stiffness.

Outerbridge Classification

The classification of chondromalacia patellae may vary depending on the severity of the lesions observed. The most commonly used classification system for chondromalacia patella is the Outerbridge classification, which divides the lesions into four stages:

  1. Stage I: Changes are limited to softening of the cartilage without showing tearing. There may be softening or thinning of the cartilage, but no cracking is present.
  2. Stage II: Superficial cracking of the cartilage is observed, but it does not penetrate to the underlying bone. These cracks can be considered minor to moderate.
  3. Stage III: Cracks reach the underlying bone, causing more extensive cartilage damage. This can lead to loss of cartilage substance.
  4. Stage IV: This stage is characterized by significant loss of cartilaginous substance, with exposure of the underlying bone. More serious degenerative changes are present, and the joint may show signs of advanced osteoarthritis.

The Outerbridge classification helps determine the severity of chondromalacia patellae and often guides treatment decisions. It is frequently used by healthcare professionals, particularly orthopedists, to assess the extent of cartilage damage and plan treatment accordingly.

It is important to note that the Outerbridge classification is an arthroscopic evaluation, meaning it is based on what the surgeon observes during an arthroscopy, a procedure that allows inspection of the interior of the the knee joint using a camera.

Prevention of Chondromalacia Patella

Prevention of chondromalacia patellae usually involves strategies to strengthen the muscles around the knee, improve joint stability, and minimize risk factors. Here are some recommendations to prevent the development of chondromalacia patella:

  1. Muscle Strengthening:
    • Quadriceps: Targeted strengthening exercises for the quadriceps muscles can help stabilize the kneecap. This may include knee extensions and squats.
    • Hamstrings: Strengthening the hamstring muscles can balance muscle strength around the knee, reducing pressure on the kneecap.
  2. Stability Exercises:
    • Balance and Proprioception: Exercises that improve balance and proprioception, such as standing on one leg, can help with knee joint stability.
    • Sliding Exercises: Controlled sliding movements can be incorporated to strengthen the stabilizing muscles.
  3. Stretching:
    • Quadriceps and Hamstrings: Regular stretching of the quadriceps and hamstrings can help maintain muscle flexibility and reduce strain on the kneecap.
    • TFL (Tensor Fasciae Latae): Stretching the TFL can be beneficial in releasing tension on the kneecap.
  4. Weight Control:
    • Maintaining a healthy body weight is crucial, as excess weight can increase pressure on the knees, increasing the risk of chondromalacia patellae.
  5. Moderation in High Impact Activities:
    • Avoiding excessive strain on the knees by limiting high-impact activities, such as running on hard surfaces, can help prevent premature cartilage wear.
  6. Appropriate Footwear:
    • Wearing appropriate footwear for physical activity, with adequate support, can help absorb shock and protect joints.
  7. Correction of Biomechanical Imbalances:
    • For some people, biomechanical imbalances may contribute to chondromalacia patellae. Regular assessments by healthcare professionals can help detect and correct these imbalances.
  8. Proper Warm-up and Cool-down:
    • Before any physical activity, a proper warm-up and gentle stretches can prepare muscles and joints, reducing the risk of injury.

Treatment


Chondromalacia patella, also called patellofemoral syndrome, is a condition where the cartilage under the kneecap (patella) becomes softened or damaged, often leading to knee pain, especially when flexion or extension. Treatment for chondromalacia patellae may involve conservative approaches aimed at relieving pain and improving knee function. Here are some common treatment options:

  1. Osteopathy:
    • An osteopathic program may be prescribed to strengthen the muscles around the knee, with emphasis on the quadriceps and hamstring muscles.
    • Stretching exercises can help improve muscle flexibility and reduce strain on the kneecap.
  2. Drugs :
    • Nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may be recommended to reduce inflammation and relieve pain.
    • Analgesics may also be used for pain relief.
  3. Weight Control:
    • Maintaining a healthy body weight can reduce pressure on the knee, thereby relieving symptoms.
  4. Orthotics:
    • Orthotics, including orthotic insoles, may be used to correct biomechanical abnormalities that contribute to chondromalacia patella.
  5. Reduction of High Impact Activities:
    • Avoiding or reducing high-impact activities, such as running on hard surfaces, can help prevent symptoms from getting worse.
  6. Injections:
    • Corticosteroid injections may be considered to reduce inflammation.
    • Viscosupplementation injection can help improve joint lubrication.
  7. Therapeutic Exercises:
    • Some specific exercises, such as isometric contraction quadriceps exercises, can be included in the rehabilitation program.
  8. Surgery :
    • In severe and persistent cases, when conservative treatments do not work, surgery may be considered. This may include cartilage debridement surgery, patella realignment, or other procedures depending on the specific situation.

Radiographic Signs

Radiographic signs of chondromalacia patellae can be identified using imaging tests such as x-rays. These signs provide indications about the condition of the cartilage under the kneecap. Some of the radiographic signs associated with chondromalacia patella include:

  1. Cartilage Lightening: X-rays may reveal lightening or reduced opacity of the cartilage under the kneecap. This may indicate softening or wearing away of the cartilage, characteristic of chondromalacia.
  2. Cartilage Surface Irregularities: X-ray images may show irregularities in the surface of the cartilage under the kneecap, including cracks, rough areas, or cartilage defects. These changes reflect the alteration of the cartilage.
  3. Joint Space Narrowing: The joint space, the space between the kneecap and femur, may appear narrowed on x-rays due to loss of cartilage height.
  4. Osteophytes: Osteophytes, also called bone spurs, can form on the edges of bony surfaces in the kneecap area. These bony growths are a response to cartilage wear.
  5. Subluxation of the Patella: In some cases, x-rays may show subluxation of the patella, indicating poor position of the patella in relation to the femur.
  6. Stage of Severity: Certain classifications can be used to determine the stage of severity of chondromalacia patella based on radiographic signs, ranging from mild to severe stages.

It is important to note that x-rays may not always reveal all the details of chondromalacia patella, because the cartilage is not directly visible on x-ray images. In some cases, more advanced imaging tests, such as MRI (magnetic resonance imaging), may be recommended to provide a more detailed assessment of the cartilage and surrounding structures.

The final diagnosis and determination of the treatment plan is usually based on a comprehensive evaluation, including clinical information, medical history, physical examinations, and imaging results.

Chondromalacia of the patella: lateral movement of the patella leads to premature wear of the cartilage.

Conclusion

In conclusion, chondromalacia patellae is a knee condition characterized by softening or wearing away of the cartilage beneath the kneecap, often leading to pain and discomfort. Treatment of this condition may involve various approaches depending on the severity of the symptoms and the individual characteristics of the patient.

Treatment options range from conservative approaches, such as physiotherapy or osteopathy, to medical interventions, including the use of anti-inflammatory medications, injections, or even surgery in severe and resistant cases.

It is imperative to consult a health professional for an accurate diagnosis and a treatment plan adapted to each situation. Multidisciplinary treatment, combining different therapeutic approaches, can often provide the best results for the effective management of chondromalacia patella, improving mobility, relieving pain and promoting healing.

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