Patellar tendinitis

Disease Description (Causes and Symptoms)

• Definition: Patellar tendinitis (Jumper's knee) is a condition involving degenerative changes, inflammation, or partial tearing of the patellar tendon, which connects below the patella (kneecap), and is a tendon disorder related to knee extension function.
• Causes/Pathophysiology:
  • Repeated and excessive vertical or impact loading (jumping, landing, sudden stopping or changes in direction, etc.) leads to accumulated microtears and degenerative changes in the patellar tendon.
  • Muscle imbalance (quadriceps weakness), insufficient flexibility, inappropriate weight-bearing or technique, and inadequate recovery are risk factors.
• Main symptoms:
  • Tenderness directly below the patella (upper part of the shin), and pain with movement (especially running, jumping, and going up or down stairs); warmth and swelling may also occur.
• Diagnosis:
  • Clinical examination (location of tenderness and reproduction of pain under load—for example, a single-leg decline squat).
  • Imaging tests: X-ray (to rule out bone lesions), ultrasound (tendon thickness, structural changes, and increased vascularity), MRI (to identify partial tears and degenerative changes).

Treatment Methods (Latest Standard Treatments, Medications, Procedures, Surgery, Lifestyle Management, and Precautions)

• Conservative treatment (first-line treatment)
  • Activity modification: Limit high-intensity jumping and landing movements, and gradually rehabilitate within the range allowed by pain (gradual loading is recommended rather than complete immobilization).
  • Physical therapy: Stretching, quadriceps strengthening (especially eccentric exercises, such as decline squats), and strength and functional retraining.
  • Supportive devices: A patellar strap (taping or infrapatellar strap) may help relieve pain.
  • Medications: NSAIDs (short-term pain management) and topical analgesics.
  • Ice application and control of initial inflammation.
• Interventional treatment (considered when conservative treatment fails)
  • Extracorporeal shock wave therapy (ESWT): Pain relief and functional improvement have been reported in chronic tendon disorders.
  • Injection therapy: Regenerative treatments such as PRP (platelet-rich plasma) may be effective in some patients, but the evidence is mixed. Corticosteroid injections may provide short-term relief, but are generally not recommended because of the risk of weakening the tendon tissue and recurrence.
• Surgical treatment
  • If symptoms persist despite conservative treatment (at least 3–6 months, usually 6 months or longer), surgery such as arthroscopic debridement of the tendon and repair of the torn area may be considered.
  • Surgery is limited to cases with persistent symptoms and functional impairment.
• Prognosis
  • Most cases improve with conservative treatment, but recovery takes several months (usually 3–6 months, and longer in severe cases).
  • Early rehabilitation, strengthening, and load management are important.
• Precautions / complications
  • Avoid excessive rest or complete immobilization, as it can cause muscle weakness.
  • Continued repetitive strain can lead to chronic symptoms, partial tearing, or patellar tendon rupture.
  • Corticosteroid injections should be used cautiously because they may increase tendon fragility.

Checklist Before an Outpatient Visit (Including Items to Bring and Example Questions)

• Items/materials to bring or submit
  • List of currently used medications (especially whether you are taking anticoagulants, antiplatelet medications, or steroids)
  • Previous medical records and test results (if available, recent X-ray, ultrasound, or MRI images and reports)
  • Pain diary: when the pain occurs, its frequency and intensity (pain score), aggravating and relieving factors (e.g., jumping and stairs), and activities limited by the pain
  • Exercise and occupational history: types and frequency of sports you mainly do, training volume, and whether your occupation places stress on your knees
• Materials to show the healthcare professional during the visit
  • Photographs (with the painful area marked) and a video reproducing the exercise movement (if available)
• Self-care checklist before the visit
  • Record self-treatments attempted for pain relief (ice application, use of supports, medication, etc.) and their effects

General Example Questions to Ask the Doctor

• What are the side effects of this medication (or treatment)?
• What are the expected treatment duration and prognosis?
• Which activities should I avoid during daily life and exercise, and when can I resume them?
• If conservative treatment (exercise and physical therapy) is not effective, what are the next options?
• If surgery is necessary, under what circumstances is it needed, and how long is the recovery period after surgery?

Examples of Condition-Specific Questions

• When is it safe for me to resume jumping and competition in the sport I play (e.g., basketball or volleyball)? What are the stages and criteria for returning?
• If the current ultrasound (or MRI) findings show a partial tear or degenerative changes, what degree of improvement can be expected with nonsurgical treatment, and how long is it expected to take?