Anterior Knee Pain

Overview

Pain in the front of the knee is a very common complaint at all ages, especially in women. Evidence suggests the greater pelvic width and leg angulation, differences in muscle function, and unique gender related issues such as estrogen in women may all play a role.

However, anterior knee pain is not a diagnosis in itself anymore. Most anterior knee pain is related to the patellofemoral joint and its musculature and ligament support. So-called "patellofemoral pain" has become the most common knee symptom in the average orthopedic outpatient clinic. Depending on the exact cause, it is 2-7 times more prevalent in women.

It is estimated that up to 10% of all aging knee pain is due to isolated patellofemoral arthritis. Because the exact source of pain can be difficult to isolate and is often multifactorial, patellofemoral pain syndrome requires careful diagnosis and proper management to avoid unnecessary, ineffective or potentially harmful treatment.

Key Points

While the pain of inflammation or muscle soreness may be temporary, pain due to structural damage (e.g. arthritis) can be made worse by ignoring symptoms of pain, swelling, catching, and stiffness.

• An accurate, early diagnosis is critical to avoid irreparable damage from improper activity or training
• Non-operative solutions only work if accumulative joint damage is not too great.
• Self diagnosis is rarely successful if pain is severe enough to cause a limp or a change in activity or work behavior.
• Knee pain associated with climbing stairs and squatting are most often due to kneecap problems

Common Causes of Patellofemoral Pain

Pain in the front of the knee can come from many sources such as:

• Weak or overused muscles
• Kneecap (Patella)
• Inflammations and tendon injury (Bursitis, Tendinitis)
• Loose ligaments with instability of the kneecap
• Articular cartilage damage (Chondromalacia Patella)
• Swelling due to fluid build up in the knee joint
• An overload of the extensor mechanism of the knee with or without malalignment of the patella

Basic Sources of Patellofemoral Pain

Muscular: Excessive muscle tightness (inflexibility), fatigue or tearing (strain) of quadriceps or hamstring muscles, muscular strength imbalances, overuse/disuse

Structural Damage: Chondromalacia (chondro = cartilage; malacia = softening) patella (kneecap), patella arthritis, stress fracture, direct traumatic injury

Congenital Dysplasia: Patella alta (high patella), facet or trochlear dysplasia

Malalignment: Tilted patella, intoeing rotation of the legs (persistent femoral anteversion) knock knee (excessive valgus deformity)

Instability of the Patella: Maltracking with subluxation (partial) or complete dislocation of the knee cap; damaged or stretched ligament support

Inflammatory: Bursitis, Tendinitis

Overuse of Muscles

Bending and overuse of the knee leads to high repetitive pressures between the kneecap and the femoral groove. The resulting overload, muscle fatigue and imbalances are the most common source of soreness and weakness around the knee.

Who are most vulnerable to this problem?

• Patients who are too aggressive in starting a fitness program
• Young mothers or grandmothers who repeatedly squat to pick up little children
• Workers that must climb
• Runners and athletes that over train

Younger patients need to be analyzed for inflexibility acquired from rapid teenage growth or poor conditioning. Inactivity can be just as bad as too much activity. Just sitting with your knee bent can be painful when you get up.

Treatment: A quality physical therapy program prescribed by your orthopedic surgeon after proper evaluation is the best place to start. At our center we teach improved exercise or work behaviors combined with patellofemoral specific rehabilitation. Braces and orthotics may also be helpful.

The good news is that these conditions can respond well and do not need operative treatment. Beware of exploratory arthroscopic surgery or the suggestion that a "lateral release" may be helpful. Such approaches often lead to worse symptoms if not carefully planned.

Structural Damage

Structural damage to the patella or the groove in which it travels (the femoral trochlear groove) can occur from direct injury, such as from a car accident (also called dash board knee). Such blows can kill the cells in the surface cartilage layer and lead to softening or complete loss of tissue covering the bones. Either the kneecap or the femoral surface, or both, can be affected.

Noisy knees (crepitation) with crunchy sounds during knee bending (e.g. stair climbing, squatting, working out with weights) are one of the first signs of articular damage (chondromalacia and degenerative arthritis).This stage is often misleadingly painless. Pain and swelling develop with time and further overactivity.

Being overweight is a big culprit in setting off these symptoms. This is often the case in women after pregnancy or menopause.

Accumulative overuse (improper fitness or athletic training) combined with aging can lead to advanced arthritis (wear-out of the joint surface) at a young age (less than 40 years).

Treatment: When caught early, anti-arthritis measures such as weight loss, quad exercises, and learning smarter activity habits (like avoiding knee bends, switching to safer exercise), combined with cautious use of medication or injection, can help.

If swelling and limping are severe despite these measures, then arthroscopic surgery may help. For complicated cases patellofemoral realignment and conservative resurfacing (either biological or prosthetic) may be necessary.

How Arthroscopy Can Help Your Problem

• Provides a more accurate diagnosis
• Relieves some of the pain of inflammation by washing out the knee
• Quiets down the aggravation of rough joint surfaces and reduces mechanical irritations
• Combined with other surgical measures it can realign or stabilize the kneecap
• Removes a painful plica

Congenital Dysplasia

Some people are born with misshaped kneecaps, or the groove in which the patella must travel is too shallow. This can lead to abnormal wear or instability. Such conditions may be present in youth, but may not be noticed until adulthood, when aging or excessive activity begins to aggravate the knee.

Treatment: Exercising can help, but if symptoms continue to be disabling, operative treatments can be used to correct the forces on the kneecap. Such operations require the surgeon to have special experience and training.

Malalignment /Patella Instability

Malalignments can involve the whole leg or just the kneecap joint (patellofemoral) portion of the knee. Persistent intoeing from birth is often due to internal rotation of the femur bone and contributes to a mal-adaptation growth pattern known as the "malicious mal-alignment syndrome". This is characteristically seen in young girls and persists into adult life. This is an inherited characteristic between mother and daughter.

Many patients complain of aching while exercising or playing sports. Others see that their kneecap is tilted or out of position. This can lead to pain from excessive lateral (outer side of knee) patella pressure. In advanced cases the patella begins to wear and deform, causing mechanical symptoms of sharp pain or catching. Sometimes the knee just gives way, resulting in excessive falls.

Such instability can be a pseudo phenomenon of pain-induced muscle weakness in the leg. Sometimes the kneecap actually jumps out of place. Recurrent patella dislocation (either partial or complete) is due to loose ligaments, patellofemoral dyplasia, or both.

Treatment: Most overuse/overload patellofemoral pain responds initially to non-operative treatment. In younger patients, treatment always begins with methods such as icing, arch supports, physical therapy, patella support braces, and moderate short term anti-inflammatory medication. A taping and rehabilitative program (McConnell) should be tried.

True patella dislocations can be managed non-operatively with arthroscopic surgery, or with more complicated ligament and/or extensor realignment surgery. If arthritis or severe chondromalacia develops and other efforts fail, then patella replacement can be very helpful in both the older and younger patient.

Inflammation

Patella tendinitis results from excessive overload or overuse of the extensor mechanism of the knee. Known as "jumper's knee," this injury occurs not only with the strain of jumping, but also during landing after a jump, excessive weight lifting, or kicking. The injury is a true tearing and degeneration of the tendon at the microscopic level with failure to heal (tendinosis).Basketball, soccer, Tai-Bo, step aerobics, volleyball - all can produce this injury.

Ignoring this pain may lead to a sudden rupture of the patella tendon and eventually to emergency surgical repair.

Treatment: The proper diagnosis is for the patient to undergo an eccentric tendon therapy program, bracing, and modified activity. In difficult cases our center has pioneered leading approaches to stimulating the healing of injured tendons. Percutaneous methods in the office, as well as outpatient arthroscopic and surgical tenotomy, are very successful.

Prepatella Bursitis

Excessive kneeling (e.g. wrestling, scrubbing floors, laying carpet) or direct trauma (blunt force from a car accident or fall) can cause increased fluid or bleeding in this sac. This can result in a bump (water on the knee), pain and redness. Infection can follow.

Treatment: Anti-inflammatory medication, removal of fluid and steroid injection. In persistent cases the sac may to be removed with minor surgery.

Additional Sources of Pain

Synovial Plica

A plica is a normal fold of tissue within the knee that can cause patellofemoral pain symptoms if aggravated by injury of overuse. It is diagnosed by a distinct presence of tenderness along the inside of the kneecap. There is often a popping or catching sensation on bending the knee.

Treatment: Physical therapy, local icing, injection and relative rest most often help. Arthroscopic excision of this functionless structure can be a practical and simple remedy for persistent cases.

Visit www.kneepaininfo.com or www.JointHealing.com for further information.