Knee bursitis or patellar bursitis has many names; housemaid's knee, clergyman's knee, and carpenter’s knee.  

The condition involves swelling of one or more bursae present at the front of the knee. The prepatellar bursa is located superficially between the skin and the kneecap bone. Due to its superficial location, it is most commonly involved in traumatic conditions and regular wear and tear.

Direct fall on a knee, acute trauma, repetitive friction contribute to the development of this condition. About 10% of the runners develop patellar bursitis at some stage. Non-infectious conditions pre-disposing to patellar bursitis include diseases like arthritis, gout, syphilis, and tuberculosis. 

Acute trauma results in obviously significant symptoms, while chronic low-grade trauma may remain asymptomatic with slight swelling in front of the kneecap area.

Patellar tendonitis or jumper's knee is another prevalent condition found in athletes; about 40-50% of professional basketball players succumb to this condition. It involves inflammation of the tendons that connect the patella to the tibia.

Anatomy

The quadriceps muscles of the thigh are connected to the inferior pole of the patella by the common quadriceps tendon. The attachment is made possible via the patella, a sesamoid bone.

Another ligament, the patellar ligament, connects the bottom of the patella to a tuberosity on the tibia, the tibial tuberosity. Under normal circumstances, the quadriceps generate a force that acts through the patellar bone in a pulley-like fashion and brings about the extension of the knee. 

The patella moves up and down in the groove of the femur upon bending and extending the knee. Bursae around the knee are arranged in two groups;

• around the patella, namely suprapatellar bursa, the superficial and deep infrapatellar bursae, and the pre-patellar bursa and
• others like pes anserinus bursa and the iliotibial bursa

Causes of knee bursitis and tendonitis

Bursa caters to cushioning effect between two bony surfaces. When the bursa present between the patella and the skin becomes inflamed or damaged, bursitis results; the condition may or may not be linked to patellar tendonitis. However, the causative factors of both diseases overlap each other.

The causative factors for knee bursitis include;

• Repeated movements as in long-distance running
• Excessive friction and wear tear as in the case of occupational injury
• Direct trauma or fall on the knee
• After knee surgery, as in knee joint replacement
• Infections as tuberculosis
• Autoimmune conditions as rheumatoid arthritis

The underlying cause of patellar tendonitis is repetitive stress on the knee and overuse that often occurs in sports or exercise. Tiny tears or micro trauma persist because of a lack of healing and recovery time in the tendon, which becomes weak and inflamed. Sports activities that involve running, jumping, squatting put undue force and strain on the patellar tendon resulting in tendonitis.

Some causative factors include;

• Tight and inflexible leg muscles
• Imbalanced strength between the different muscles of the leg
• Malalignment of feet, ankles, and legs
• Obesity and overweight
• Improper shoes without enough padding
• Flat and hard playing surfaces
• Chronic diseases that damage and weaken the tendon
• An extended period of excessive training

Signs and symptoms of patellar- knee bursitis and tendonitis

Knee bursitis presents as;

• Swelling on the front of the affected knee
• Redness, a sign of inflammation, on the front of the knee
• The affected knee is tender to touch
• Pain on kneeling
• Joint stiffness and difficulty in straightening or bending the knee

Presenting complaints of patellar tendonitis are;

• Anterior knee pain at the base of the kneecap
• Pain is localized to the inferior pole of the kneecap
• The knee is tender to touch
• Swelling of the kneecap area
• A burning feeling in the region over the kneecap
• Movements at the knee joint are painful as kneeling and getting up from a squat

The pain of patellar tendonitis is associated with load-bearing. It increases with an increased demand on the knee extensor muscles, particularly with activities that store and release energy in the patellar tendon.

The patient suffering from tendinopathy complains of pain with prolonged sitting, squatting, and climbing stairs. There is rarely any pain in a resting state.

Pain instantly starts with loading and diminishes as soon as the load is removed. However, repeated loading improves the pain in such patients. The pain may improve with repeated loading. Walking downstairs or performing a decline squat aggravates the pain.

Diagnosis of patellar -knee bursitis and tendonitis

History of presenting complaints usually indicates the triggering event or the nature of the disease. Special tests help confirm the diagnosis of knee bursitis.

Pain and tenderness on touch indicate bursitis or tendonitis. Movement at the knee joint, flexibility, and muscle strength are tested.

Radiological analysis, including X-rays, MRI scans, and CT scans, gives detailed insight into the injury. These tests also help to distinguish between tendonitis and bursitis.

Treatment of patellar bursitis and tendonitis 

Treatment of either condition depends on the severity of the injury.

Conservative treatment is the first therapy line comprising measures to reduce pain, rest, stretching, and strengthening of leg muscles.

1. Immediately after the injury to first few days

1. RICER

A period of controlled rest helps manage both conditions.

Ice or cold compress and elevation help ease inflammatory reactions and reduce swelling. In the absence of an open wound, compression also helps to alleviate swelling and pain in the affected joint area.

If the symptoms worsen or do not seem to resolve, referral to a specialist is advised.

• Medication

Over-the-counter (OTC) drugs for short-term pain and inflammation reduction are advised in either bursitis or tendonitis. These include ibuprofen (Advil), naproxen sodium (Aleve), and acetaminophen (Tylenol).

Severe pain is managed by corticosteroid injection in the area around the patellar tendon or bursa. However, corticosteroids weaken the tendons over time, so this should be a last resort therapy.

Corticosteroids may be given via iontophoresis. The drug is applied topically, and a low electrical charge pushes the drug molecules into the skin and the joint.

• TENS

Patellar bursitis and tendonitis benefit from TENS application. The therapy improves circulation and relieves pain.

While using TENS, make sure not to place the electrodes on the bony surfaces. Place the electrodes above and below the knee joint to get the maximum out of this therapy.

• Surgery

When conservative treatment fails to bring the desired results, surgical intervention is employed.

The knee cap and tendon are opened up and scraped off any accumulated debris. Arthroscopic surgery is a less invasive option requiring only four small incisions in the knee. Arthroscopic repair also shortens the recovery time.

• Other alternatives

Some other options for managing tendonitis include;

• Injection of platelet-rich plasma
• Ultrasound-guided dry needling procedure
• Polidocanol injections
• Hyperthermia thermotherapy
• Extracorporeal shock wave therapy

• After few weeks

• Massage

Massage helps to relax the tense muscles of the legs and thigh. Patellar tendonitis and bursitis heal and recover faster if therapy options adjunct with massage of thigh or leg muscles.

• Therapeutic ultrasound

The module works to relieve lingering pain of chronic tendonitis and bursitis of the patella.

• Active rehabilitation

Physical therapy aims to reduce your pain and inflammation and stretch and strengthen your leg and thigh muscles.

Wearing a brace or crutch may be required in some patients. The application of K-tape help stabilizes the kneecap during physical therapy sessions.

A pain-free phase of tendonitis and bursitis merit physical rehabilitation to prevent a recurrence.

Physical therapy addresses the following faculties of patellar bursitis and tendonitis;

• Reduction of pain and swelling
• Improve movement and range of motion
• Enhance flexibility
• Strengthen the thigh and leg muscles to increase the stability of the patella
• Improvement of balance, agility, and endurance

Stretching exercises for patellar bursitis and tendonitis include isometric exercises as well eccentric ones. Isometric exercises are conducted while joint angle and muscle length are maintained, thereby relieving pain.

Eccentric loading exercises are one of the best options for athletes that undergo therapy for their patella while still playing. These exercises involve performing squats on a decline board placed at 25 degrees angle.

All loading programs are beneficial in reducing pain and returning function; however, the eccentric-concentric design shows greater patient compliance. They are usually done with bodyweight squats followed by the addition of a significant load.  Leg press or knee extension done via gym equipment cater to control the amount of loading.

Flexibility exercises for the thigh and calf are also part of the physical rehabilitation program. The program is designed specifically for each patient.

In patellar bursitis, exercises that allow static contraction of the quadriceps are taken up to reduce the pain. Stretching exercises are adopted later in therapy.

• Rehab exercises for patellar bursitis

Heel slides

• Lie on the floor on your back.
• Keep the affected knee straight.
• Bend your healthy knee.
• Move your affected leg and slide the heel slowly across the floor inwards towards your buttocks.
• Hold for few seconds and slowly straighten your knee to bring it back to starting position.
• Repeat at least twelve times.

Quad sets

• Sit on a floor and keep your affected leg straight.
• Place a small hand towel rolled up under your affected knee.
• Bend your healthy leg with feet planted comfortably on the ground.
• Press the back of the affected knee so that you feel a tightness in the thigh muscles.
• Hold for few seconds, followed by the rest of few seconds.
• Repeat at least twelve times.

Straight leg raises

• Lie on your back on the floor.
• Bend your healthy leg and place your foot on the ground.
• Keep your affected leg straight.
• Your lower back should maintain its standard curve, enabling you to slip your hand through the space between the floor and the back.  
• Press your knee down on the floor to flatten it against the floor. There should be a tightness felt in the thigh muscles.
• Holding your knee straight and tight, engage the thigh muscles and lift the affected knee from the ground.
• Lift as high as you are comfortable, at least thirty centimeters off the ground.
• Hold the lift for few seconds, then lower it back slowly and in a controlled motion.
• Rest before repeating the lift at least twelve times.

Rehab exercises for patellar tendonitis

Half-squat

• Stand and keep your feet at a distance of about shoulder-width apart.
• Turn your feet outwards at 45 degrees. Make sure not to extend your knees beyond your feet at all times during the exercise. 
• Keeping your back straight, engage and tighten your buttocks.
• Now slowly bend your knees and lower your body in a squat position but not down.
• Stop mid-way or about one-quarter of the way down the floor.
• Keep your back straight during this exercise and tilt your pelvis forward.
• Repeat at least twelve times.

Step up

• Place a footstool on the floor with only one step. You can use the bottom stair step if you have access to a stairway.
• Take support from a chair in case of a footstool or the railing of the stairs if you are not stable.
• Keep your back straight while doing this exercise.
• Climb up the step with your affected leg.
• Do not push back the healthy leg. Take the next step with the healthy one.
• As you take the step up, keep your knee moving straight in line with your middle toe.
• Once steady on the footstool or stair, step down with your affected leg first, followed by the healthy one.
• Repeat stepping up and down at least twelve times, counting both legs.

Step down

• Stand on a footstool. Take support from a chair if you need it.
• Starting with your healthy side, step down from the footstool.
• Lightly touch the floor with a healthy leg.
• Bring your other leg down, keeping the affected knee in line with your middle toe.
• Once on the ground, take a rest for a few seconds, climb back to the footstool, and repeat the movement.
• Repeat at least twelve sets.

Prevention of patellar - knee bursitis and tendonitis

• Continue with physical exercises at home to maintain strength and flexibility of the leg muscles.
• Avoid kneeling position for prolonged periods or do not adopt it at all.
• Use some cushion while kneeling.
• Wear knee pads during sports and other activities involving kneeling.
• Always warm up the body before playing a sport or heavy physical activity.
• Adopt a gradual increase in physical activity instead of a sudden increase.
• Avoid overloading your muscles.