Patellar Tendonitis (PSS): A Comprehensive Guide

Synonyms: Jumper's knee, Patellar tendinopathy

Patellar tendonitis, also known as Patellar Tendon Syndrome (PSS) or jumper's knee, is a common overuse injury that affects athletes involved in sports that require repetitive jumping, such as basketball, volleyball, or soccer. This condition results from chronic strain on the patellar tendon, leading to pain, inflammation, and potential degenerative changes at the lower pole of the kneecap.

Table of Contents:

  1. Systematics of the Kneecap and Patellar Tendon
  2. What is Patellar Tendonitis?
  3. How Does Patellar Tendonitis Occur?
  4. Symptoms of Patellar Tendonitis
  5. Diagnosis of Patellar Tendonitis
  6. Clinical Diagnostics
  7. Imaging Diagnostics
  8. Classification of Patellar Tendonitis
  9. Differential Diagnoses (Similar Conditions)
  10. Therapy for Patellar Tendonitis
    • Conservative Therapy
    • Surgical Therapy

1. Systematics of the Kneecap and Patellar Tendon

The patellar tendon, sometimes referred to as the ligamentum patellae, connects the lower tip of the kneecap (patella) to the tibial tuberosity (shinbone). It acts as an extension of the quadriceps tendon, facilitating knee extension. When the quadriceps muscles contract, the force is transmitted via the patellar tendon to straighten the leg, enabling movements such as jumping or standing up.

2. What is Patellar Tendonitis?

Patellar tendonitis is a painful condition caused by inflammation or degeneration of the patellar tendon, particularly at its insertion point on the lower pole of the kneecap. It is primarily caused by chronic overloading, especially in activities that involve forceful knee extension, such as jumping and abrupt changes in direction. Competitive athletes, especially those in jumping sports, are most commonly affected. However, it can also occur in non-athletes due to certain anatomical predispositions.

3. How Does Patellar Tendonitis Occur?

The exact cause of patellar tendonitis is still debated, but it is generally accepted that degenerative changes in the tendon, rather than inflammation, are responsible for the pain. Overuse causes microtears and abnormal cellular activity in the tendon, leading to tissue degeneration. Factors such as high kneecap positioning (patella alta) or a congenital weakness of the ligaments can also predispose individuals to this condition.

4. Symptoms of Patellar Tendonitis

The hallmark symptom of patellar tendonitis is pain localized at the lower tip of the kneecap, typically worsening during activities that strain the knee joint. Early stages of the condition may present with pain only during physical exertion, while advanced stages can cause discomfort even during daily activities such as climbing stairs. Swelling, tenderness, and redness around the affected area are also common.

5. Diagnosis of Patellar Tendonitis

Diagnosing patellar tendonitis starts with a clinical examination that includes a thorough patient history and physical examination. Tenderness at the patellar tendon’s attachment to the kneecap is a key finding. The doctor may also assess the surrounding tissues for swelling or inflammation. If needed, additional imaging techniques are employed to confirm the diagnosis and determine the severity.

6. Clinical Diagnostics

During the physical examination, the physician applies pressure to the lower pole of the kneecap to check for tenderness and swelling. The patient may be asked to perform movements, such as straightening the knee against resistance, to provoke pain and help confirm the diagnosis.

7. Imaging Diagnostics

Magnetic resonance imaging (MRI) is the most important tool for evaluating the severity of patellar tendonitis. It helps detect partial tears, thickening, calcification, and tissue degeneration. Ultrasound can also be used to assess the general condition of the patellar tendon but lacks the precision of MRI in diagnosing the condition.

8. Classification of Patellar Tendonitis

Patellar tendonitis is classified into five stages based on severity:

  1. Stage 1: Pain after exertion.
  2. Stage 2: Pain during and after exertion.
  3. Stage 3: Persistent pain before, during, and after exertion.
  4. Stage 4: Partial rupture of the patellar tendon.
  5. Stage 5: Complete rupture of the patellar tendon.

9. Differential Diagnoses (Similar Conditions)

Patellar tendonitis shares symptoms with several other orthopedic conditions, including:

  • Osgood-Schlatter Disease: Affects the patellar tendon attachment at the tibial head.
  • Sinding-Larsen-Johansson Disease: Involves bone fragments breaking off from the kneecap.
  • Stress Fractures: Microfractures in bones due to overuse.
  • Hoffa's Fat Pad Syndrome: Inflammation of the fat pad located behind the patellar tendon.
  • Prepatellar Bursitis: Inflammation of the bursa in front of the kneecap.
  • Retropatellar Chondropathy: Cartilage damage behind the kneecap.

10. Therapy for Patellar Tendonitis

Conservative Therapy

Rest and Activity Modification:
The cornerstone of conservative treatment is resting the knee and avoiding activities that exacerbate the condition. A gradual return to physical activity with proper warm-up and stretching exercises is recommended.

Pain Management:
Cold therapy, anti-inflammatory medications (NSAIDs), and pain-relieving ointments can help manage symptoms but do not address the underlying cause.

Physical Therapy:
Targeted exercises aimed at strengthening the quadriceps and hamstring muscles can help alleviate strain on the patellar tendon.

Extracorporeal Shock Wave Therapy (ESWT):
ESWT uses shock waves to stimulate healing in the affected tissue. Studies show that this therapy increases blood circulation, promotes tissue regeneration, and reduces pain, making it an effective alternative to surgery for early-stage patellar tendonitis.

Surgical Therapy

In severe cases, surgical intervention may be required. Surgery aims to remove degenerative tissue, repair partial tears, or reconstruct the patellar tendon. Recovery from surgical treatment is lengthy, often taking 6 to 12 months.

Conclusion

Patellar tendonitis (PSS) is a common yet treatable condition affecting athletes and non-athletes alike. Early recognition and conservative treatment can prevent the progression to more severe stages, while advanced cases may require surgical intervention. Understanding the nature of the condition and adopting appropriate preventive measures can ensure long-term joint health.