Patellar tendinopathy

What is patellar tendinopathy?

Patellar tendinopathy is a painful condition of the tendon located below the kneecap, caused by repetitive overuse. It affects up to 45% of jumping athletes.¹ The term "jumper's knee" accurately describes this common condition among athletes who put intense strain on their knees.

The anatomy of the patellar tendon

Your patellar tendon is about 4 to 5 cm long. It connects the bottom of your kneecap to your shin bone. This tendon transmits the force from your quadriceps muscle to your leg, enabling you to jump, run, and climb stairs.

The tendon is made of collagen fibers organized into parallel bundles. This structure allows it to withstand significant forces. For instance, during a jump, your patellar tendon can support up to 8 times your body weight.

The most vulnerable point is where the tendon attaches to the kneecap. This is also where pain most commonly appears with patellar tendinopathy.

Tendinopathy vs. Tendinitis: What's the Difference?

The term "tendinopathy" better reflects the reality.² Studies show that most chronic tendon problems are not inflammatory. This distinction is important: since the condition is generally not inflammatory, anti-inflammatory medications have limited usefulness.

What are the causes of patellar tendinopathy?

Patellar tendinopathy occurs when the tendon is repeatedly overloaded beyond its capacity to recover. Repetitive jumping, quickly increasing your training, and certain biomechanical factors like muscle stiffness all contribute to this cumulative overload.

The tendon overload mechanism

Your tendon functions like a strong rope. Every time you jump or run, this 'rope' experiences significant forces. Normally, your tendon repairs itself during rest.

The problem occurs when demands exceed the body's capacity for repair. Collagen fibers become disorganized, and areas of degeneration gradually appear.² This process of cumulative microtrauma characterizes tendinopathy.

The main risk factors

A volleyball player might perform hundreds of jumps each week. Every jump creates a force equivalent to several times their body weight. Over time, these small injuries can accumulate if the tendon doesn't get enough rest.

What are the symptoms of patellar tendinopathy?

The main symptom is pain located just below the kneecap, in the tendon itself. This pain typically appears during or after activities like jumping and running. Morning stiffness is common, and the pain often lessens after warming up.

The typical presentation

The pain associated with patellar tendinopathy is characteristic. It is located precisely at the lower pole of the kneecap, where the tendon attaches. You can often point to it exactly.

Initially, pain only appears after activity. You might finish your workout without any problems, then feel the pain a few hours later or the next morning. If the condition worsens, pain will start to appear during the activity itself.

The 4 Stages of Progression

This classification helps determine the best treatment approach and what to expect for recovery. Stages 1 and 2 generally respond better to non-surgical treatment.

How is patellar tendinopathy diagnosed?

Diagnosis is mainly based on a physical examination. This includes pain localized just below the kneecap, tenderness when the tendon is touched, and pain that reappears during a single-leg squat. Imaging tests are usually not needed.

Clinical evaluation

Your physiotherapist makes the diagnosis by combining several factors.

• When did the pain start?
• What activities aggravate it?
• Have you increased your training volume recently?

• Palpation of the tendon (sensitivity to touch?)
• Single-leg squat test on an inclined surface⁵
• Quadriceps strength assessment
• Thigh muscle flexibility tests

The most telling test is the single-leg decline squat. For this test, you stand on one leg on a surface inclined at 25 degrees and slowly lower yourself. This puts significant stress on the tendon and often brings back the typical pain.

The role of imaging

Be cautious about imaging results: many athletes have abnormal tendons on ultrasound scans but don't experience any pain. Therefore, imaging results must be interpreted in the context of your symptoms. In most cases, no imaging is required.

How does physical therapy treat patellar tendinopathy?

The main treatment combines load management and progressive strengthening exercises. Isometric exercises provide rapid pain relief.⁴ Eccentric and heavy slow resistance exercises stimulate tendon remodeling over several weeks.

The Principle of Load Management

The key to treatment is finding the right balance of activity. Too little exercise and the tendon weakens. Too much exercise and the irritation persists.

Your physical therapist will help you identify your optimal load zone. This is the level of activity that stimulates tendon adaptation without further irritating it.

Specifically, this means:

• Temporarily reduce or eliminate aggravating activities (jumping, sprinting)
• Maintain moderate physical activity (cycling, swimming, walking)
• Gradually introduce therapeutic exercises

Types of therapeutic exercises

What doesn't work

Certain approaches are not recommended:

• Prolonged complete rest: Weakens the tendon without rehabilitating it.
• Aggressive stretching: May further irritate the tendon
• Long-term anti-inflammatory drugs: Tendinopathy is not inflammatory.
• Cortisone injections: Risk of weakening the tendon

Treatment progress

What is the recovery time?

Full recovery typically takes 3 to 6 months with proper treatment. Chronic cases might need 6 to 12 months. Continuing to play through the pain significantly extends the healing time. Patience is crucial because the tendon remodels slowly.

Prognostic factors

Studies show that elite athletes who continue to play experience symptoms for an average of 32 to 76 months. These numbers often reflect cases that were not managed well. With appropriate and early care, the outcomes are much better.

Return to Sport

• Light jogging (2-3 weeks)
• Moderate intensity running (2-3 weeks)
• Jumping on two legs (2-3 weeks)
• Jumping on one leg (2-3 weeks)
• Sport-specific training (progressive)

When should you see a specialist?

Consult a specialist if there's no improvement after 3 months of consistent physiotherapy, if the pain limits your daily activities, or if you suspect a tear. Shockwave therapy and PRP are options for cases that don't respond to other treatments.

Warning signs

Seek immediate consultation if you experience:

• Sudden, severe pain after an explosive movement
• Inability to put weight on the leg
• Significant swelling or bruising (blue)
• Popping or tearing sensation

These signs could indicate a partial or complete tear of the tendon, which requires urgent evaluation.

Advanced treatment options

Surgery is rarely needed. It is reserved for cases that do not respond to 6-12 months of well-managed conservative treatment.

Frequently Asked Questions

Can patellar tendinopathy be completely cured?

Yes, in most cases. With proper treatment and patience, most people recover completely and can resume their sporting activities. Persistent cases are often linked to inadequate load management or resuming activity too quickly.

Can I continue playing sports with this condition?

It depends on the severity. In Stage 1 (pain only after activity), you can often continue with some modifications. In more advanced stages, a period of relative rest is usually necessary.

Do knee braces or straps help?

Patellar straps can offer temporary relief by changing how forces are distributed over the tendon. They can be helpful during the return-to-sport phases, but they do not replace the underlying treatment.

Are anti-inflammatory drugs useful?

Anti-inflammatory medications can temporarily relieve pain, but they do not address the root cause of the problem. Therapeutic exercise remains the main treatment.

How can recurrence be prevented?

Prevention involves maintaining a strengthening program, gradually increasing loads (never more than 10% per week), adequate warm-up before explosive activities, and listening to the first signs of overload.

References

• Lian OB, Engebretsen L, Bahr R. Prevalence of jumper's knee among elite athletes from different sports. Am J Sports Med. 2005;33(4):561-567.
• Cook JL, Purdam CR. Is tendon pathology a continuum? A pathology model to explain the clinical presentation of load-induced tendinopathy. Br J Sports Med. 2009;43(6):409-416.
• Kongsgaard M, et al. Corticosteroid injections, eccentric decline squat training and heavy slow resistance training in patellar tendinopathy. Scand J Med Sci Sports. 2009;19(6):790-802.
• Rio E, et al. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. Br J Sports Med. 2015;49(19):1277-1283.
• Malliaras P, et al. Patellar Tendinopathy: Clinical Diagnosis, Load Management, and Advice for Challenging Case Presentations. J Orthop Sports Phys Ther. 2015;45(11):887-898.