Patellar Tendonitis (Jumper's Knee): Causes, Symptoms, and Treatment

What Is Patellar Tendonitis?

Patellar tendonitis (patellar tendinopathy) is an overuse injury involving the patellar tendon — the tendon connecting the patella (kneecap) to the tibial tuberosity (a bony prominence on the shinbone). This tendon is the extension of the powerful quadriceps muscle mechanism and bears enormous loads with jumping, landing, and deceleration.

The term "tendinopathy" is preferred over "tendinitis" because the primary pathology is tendon degeneration (breakdown and failure of the normal collagen structure) rather than acute inflammation.

Jumper's knee is the colloquial term reflecting the primary patient population — athletes who jump repeatedly. It's the most common knee overuse injury in basketball (in some series, 40–50% of professional basketball players report patellar tendinopathy) and volleyball.

Anatomy

The patellar tendon attaches at the inferior pole of the patella — the bottom tip of the kneecap. Tendinopathy most commonly develops at this attachment point (insertional). The tendon inserts below on the tibial tuberosity.

Causes

Patellar tendinopathy results from repetitive high-load eccentric stress on the patellar tendon:

Jumping and landing: Each jump-landing cycle transmits 3–5x body weight through the patellar tendon
Sudden increase in training volume or intensity
Hard playing surfaces
Poor jumping and landing mechanics
Quadriceps and hamstring tightness
Flat feet or increased Q-angle

Symptoms

Anterior knee pain at the inferior patellar pole — precisely localized pain at the bottom of the kneecap
Pain with loading activities: Jumping, landing, stairs, squatting
Pain that initially occurs only at the start of exercise and resolves with warm-up (early stage) → progresses to pain throughout activity → eventual pain at rest (advanced)
Morning stiffness at the anterior knee

Victorian Institute of Sport Assessment (VISA-P) questionnaire is the clinical tool used to quantify symptoms and monitor treatment progress — ask your clinician about it.

Grading (Modified Blazina Classification)

Grade	Symptoms
1	Pain only after activity; no functional impairment
2	Pain during and after activity; still able to perform
3	Pain during and after activity; performance impaired
4	Complete tendon rupture

Treatment

Patellar tendinopathy can be notoriously difficult to treat. A progressive tendon loading program is the foundation of treatment.

Eccentric Loading (Gold Standard)

The decline squat protocol (single-leg squats on a 25° decline board):

3 sets of 15 repetitions, twice daily
Performed slowly through the lowering (eccentric) phase
Initially painful — some pain is acceptable during the exercise
Evidence supports this as the most effective conservative treatment

Heavy Slow Resistance (HSR)

Heavy resistance training through full range (leg press, squats with load) also demonstrates excellent evidence — comparable to eccentric training, potentially better tolerated.

Load Management

Reduce jumping volume to a pain-tolerable level
Substitute non-jumping training (swimming, cycling) to maintain fitness

Adjunctive Treatments

Patellar tendon brace/strap: Worn just below the kneecap; deflects tendon load away from the inferior pole; provides immediate pain relief during activity
Corticosteroid injection: Reduces pain short-term but may impair long-term tendon healing; use with caution and not repeatedly
PRP injection: Growing evidence for use in chronic patellar tendinopathy
Shockwave therapy (ESWT): Good evidence for chronic cases

Surgery (Last Resort)

Patellar tendon debridement for chronic, refractory cases (>6 months aggressive conservative treatment). Recovery: 3–6 months.