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 than all
bellyache is appendicits. Most anterior knee pain is related to the
patellofemoral joint ,it’s 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 do 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 do to structural damage (eg. arthritis) can be made worse by
ignoring symptoms of pain,swelling,catching,of 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 , change activity or work behavior.
Knee pain with climbing stairs and squatting are most
often do to kneecap problems.
Common Causes of Patellofemoral
Pain
Pain in the front of the knee can come from many sources
including—weak or overused muscles,the kneecap (patella), inflammations and
tendon injury ( bursitis,tendinits),loose ligaments with instability of the
kneecap ,articular cartilage damage (chondromalacia patella), swelling due to
fluid build up in the knee joint,and 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
Structuraldamage: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 rotationof 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 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. Patients that are
too aggressive in starting a fitness program ( see discussion of overuse
syndrome) ,young mothers or grandmothers who repeatedly squat to pick up
little children, workers that must climb, runners and athletes that over train
are all examples of people vulnerable to this problem. Younger patients need
to be analyzed for inflexibility acquired from rapid teenage growth or poor
conditioning. Inactivity can be as bad as too much. Just sitting with your
knee bent can be painful when you get up (movie house sign) . Beginning a
health fitness program too quickly is a common error;look out for these “quick
fix” solutions that are often marketed to midlife women . Most provide poor or
no advice as the individual safety of their workouts. The client finds out too
late that the knee can not take these abrupt demands.
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 behavior
combined with patellofemoral specific rehabilitation . Braces and orthotics
may 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 in travels(femoral trochlear groove )can occur from
direct injury,eg.car accident-so called dash board knee. Such blows can kill
the cells in the surface cartlilage layer and lead to softening or complete
loss of tissue covering the bones .Either the kneecap or femoral surface or
both can be affected. Noisy knees (crepitation) with crunchy sounds during
knee bending,(eg stair climbing,squatting,working out with weights) are one of
the first signs of articular damage(chondromalacia and degenerative
arthritis).This stage is often missleadingly painless. Pain and swelling
develop with time and further overactivity . Ignoring these signs is a
mistake. Prevention of worse trouble and surgery depends upon early detection
and proper adjustments in activity.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.
Treatment : When caught early, anti-arthritis measures
such as weight loss,quad exercises,learning smarter activity habits like
avoiding knee bends, switching to safer exercise(non impacting),combined with
cautious use of medication or injection can help. If swelling and limp 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
:
1. Provide a more accurate diagnosis
2. Relieve some of the pain of inflammation by washing
out the knee
3. Quiet down the aggravation of rough joint surfaces
and reduce mechanical irritations
4. Combine with other surgical measures to realign or
stabilize the kneecap
5. Remove a painful plica
Congenital dysplasia : Some people are born with miss
shaped kneecaps or the groove in which the patella must travel is too
shallow.This can lead to abnormal wear or instability. Such conditions may
present in youth or not be noticed until adulthood when aging or excessive
activity aggravates the knee.
Treatment : Exercises and avoidance of aggravating
exercise can help,but if symptoms are disabiling,operative treatments are used
to correct the forces on the kneecap. Such operations require the surgeon to
acquire special experience and training .
Malalignment /Patella Instabiity : Malalignments can
involve the whole leg or just the kneecap joint(patellofemoral) portion of the
knee. Persistent intoeing from birth is often do 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. It is an inherited characteristic between
mother and daughter. The resulting knock knee shape to the leg puts extra
stress on the kneecap and favors dislocation. At the least, patients complain
of aching pain with exercise or sports. Other times,the 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 and falls occur. Such instability can be a pseudo
phenomenum of pain induced muscle weakness in the leg; other times,the kneecap
actually jumps out of place,true patellofemoral instability. Recurrent patella
dislocation either partial or complete is do to loose ligaments,patellofemoral
dyplasia ,or both.
Treatment : Most overuse/overload patellofemoral
pain responds initially to nonoperative 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 nonoperatively,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 the older patient
or the younger patient when all else has been tried.
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 pain may lead to
sudden rupture of the patella tendon and emergency surgical repair.
Treatment : Proper diagnosis followed by an eccentric
tendon therapy program,bracing,and modified activity. In difficult cases our
Center has pioneered leading approaches to stimulating the healing of injured
tendon.Percutaneous methods in the office as well as outpatient arthroscopic
and surgical tenotomy are very successful.
Prepatella bursitis : inflammation of the small
lubricating sac under the skin in front of the knee cap. Normally this sac is
flat with only a film of fluid to allow the skin over the patella to slide and
be protected when kneeling. Excessive kneeling (eg. wrestling,scrubbing
floors,laying carpet) or direct trauma (blunt force,eg. car accident or fall)
cause increased fluid or bleeding in this sac resulting in a bump (“water on
the knee”),pain and redness.Infection can follow.
Treatment : Anti-inflammatory medication,removal of
fluid and steroid injection . In persistant 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 persistant cases.
Click this link for further discussion and
illustration of kneecap anatomy:
www.kneepaininfo.com or www.JointHealing.com
