Patellar Tendonitis (Jumper's Knee)

**The patellar tendon** (technically a "tendon" because it connects muscle to bone, though some texts call it the "patellar ligament" because it connects two bones) connects the inferior pole of the patella (kneecap) to the tibial tuberosity (a bony bump on the shin just below the knee). This tendon transmits forces from the powerful quadriceps muscle to the lower leg, allowing knee extension. With every jump, sprint, or kick, enormous forces pass through this small structure — up to 7-9x body weight during landing from a jump. **Patellar tendonitis** typically affects the upper portion where the tendon attaches to the patella — the most stressed area mechanically. **The Spectrum of the Condition:** **Patellar Tendinitis (Acute):** - Acute inflammation - Less common than chronic form - Reactive response to overload **Patellar Tendinopathy (Chronic):** - More accurate term — degenerative changes rather than inflammation - Disorganized collagen fibers - Tenocyte (tendon cell) abnormalities - Neovascularization (abnormal blood vessel growth) - Most cases falling into this category **Blazina Classification (Severity):** - **Stage 1**: Pain only after activity - **Stage 2**: Pain at the start AND after activity, but disappears during warm-up - **Stage 3**: Constant pain at rest and during activity, affecting performance - **Stage 4**: Patellar tendon rupture (rare) **Distinguishing Features:** The key location is **the upper part of the patellar tendon** at its attachment to the patella. This is different from: - **[Osgood-Schlatter disease](/condition/osgood-schlatter-disease)**: Affects the LOWER attachment at the tibial tuberosity in adolescents - **[Patellofemoral pain syndrome](/condition/patellofemoral-pain-syndrome)**: Pain around or behind the kneecap (the joint surface), not the tendon - **Quadriceps tendinitis**: Pain ABOVE the kneecap (where quadriceps attaches) **Why Athletes Are at High Risk:** - Repetitive jumping creates cumulative tendon stress - Eccentric loading during landing is particularly demanding - Higher-level athletes train more frequently with less recovery - Acute spike in training volume often precipitates onset

## Root Causes **Patellar tendinopathy is fundamentally an OVERLOAD problem — the tendon's repair capacity is exceeded by mechanical demands:** **Mechanical/Activity Factors:** *Sports with Highest Risk:* - **Volleyball** (40-50% career prevalence in elite players) - **Basketball** (rapid jumping, cutting) - **Track and field** (high jump, long jump, hurdles) - **Soccer** (kicking creates repetitive eccentric load) - **Tennis** (lunging, sudden direction changes) *Specific Movements:* - **Repetitive jumping** with hard landings - **Sudden direction changes** during sprinting - **Kicking** — eccentric loading during deceleration - **Deep squats with high force** (weightlifting) - **Hill running** — increases tendon load *Training Errors:* - **Sudden increase in training volume** (>10% per week) - **Inadequate rest between training sessions** - **Hard surfaces** — concrete, asphalt - **Inadequate warm-up** - **Over-training during growth spurts** (adolescent athletes) **Biomechanical Factors:** *Lower Limb:* - **Tight quadriceps** — increases tension on patellar tendon - **Tight hamstrings** — alters knee mechanics - **Tight calves** — limits ankle dorsiflexion, increasing knee load - **Weak hip abductors** — allows knee valgus during landing - **Foot pronation** — increases tibial internal rotation *Knee-Specific:* - **High Q angle** — alters tendon loading - **Patella alta** (high-riding kneecap) — increases tendon stress - **Quadriceps imbalances** — particularly weak VMO **Risk Factors:** - Male sex (2x risk) - Age 16-25 (peak athletic years) - High training volume - History of [Osgood-Schlatter disease](/condition/osgood-schlatter-disease) (40-50% have prior history) - BMI >25 (some studies) - Genetic predisposition - Previous tendon injury - Inadequate recovery time

## Conservative Treatment (First-Line — 70-80% Success) **1. Eccentric Exercise (THE Gold Standard):** Eccentric strengthening — slow lowering against resistance — is the most evidence-based treatment for patellar tendinopathy. *Decline Squat (Most Studied Protocol):* - Stand on a **25-30° decline board** (or wedge) with both feet - Slowly lower into a squat on the AFFECTED leg only - Use the unaffected leg or hands to return to starting position - **3 sets of 15 repetitions, twice daily** - **Continue for 12 weeks minimum** - Do with progressive weight added as pain allows - Pain during exercises is acceptable (up to 4/10) and expected - Studies show **60-90% success rate** *Why Decline (Not Flat Surface):* - The decline isolates the patellar tendon - Increases tendon strain by ~25% - Critical for stimulating tendon adaptation - Flat squats are less effective for this purpose **2. Load Management:** - **Reduce sport activity** by 50-70% during initial weeks - **Pain monitoring rule**: pain during activity should stay below 5/10 and settle within 24 hours - Cross-train with cycling, swimming, elliptical - Gradually return to sport as tendon adapts **3. Stretching and Flexibility:** - **Quadriceps stretching** (essential) - Hamstring stretching - Hip flexor stretching - Calf stretching - **30 seconds, 3 reps, 3x daily** **4. Pain Management:** - **NSAIDs** for short-term pain relief during acute flares (2-4 weeks max) - Long-term NSAIDs may impair tendon healing - **Ice** 15-20 minutes after activity - **Patellar tendon strap** (Cho-Pat strap) — distributes load away from injured area **5. Physical Therapy:** - Comprehensive lower extremity strengthening - Hip and core stabilization - Movement pattern correction - Sport-specific rehabilitation ## Other Treatment Options **Shockwave Therapy (ESWT):** - Effective for chronic cases >3 months - 60-80% improvement in chronic tendinopathy - Multiple sessions typically needed - Painful during treatment **PRP (Platelet-Rich Plasma) Injection:** - Emerging evidence for chronic cases - May be better than corticosteroid for long-term outcomes - Studies showing 60-80% improvement - Multiple injections sometimes needed **Sclerosing Injections:** - Target neovascularization - Studies show benefit in chronic cases - Specialized procedure **AVOID:** - **Corticosteroid injection INTO the tendon** — increases rupture risk significantly - May provide short-term pain relief but worsens long-term outcomes ## Surgery (Last Resort — <10% of Cases) **Indications:** - Failed 6-12 months of structured conservative treatment - Persistent disabling pain limiting career - Stage 3 or 4 disease - Tendon rupture (Stage 4 — surgical emergency) **Procedures:** - **Open or arthroscopic debridement** of degenerative tendon - **Tendon repair** for partial tears - **Tendon reconstruction** for complete ruptures (emergency) **Outcomes:** - 70-90% improvement - Recovery: 6-12 months for full return to sport - Some athletes never return to pre-injury performance ## Critical Treatment Pearls 1. **Eccentric exercises are the cornerstone** — no shortcut around 12-week minimum 2. **Pain during exercise is acceptable** (up to 4/10) — necessary for tendon adaptation 3. **Don't completely rest** — this leads to deconditioning; controlled loading is essential 4. **Avoid corticosteroid injection** into the tendon — increases rupture risk 5. **Address biomechanical factors** — quadriceps tightness, hip weakness, foot pronation 6. **Be patient** — chronic tendinopathy takes 3-6 months minimum to improve 7. **Modify training** — gradual return is essential to prevent recurrence