Calvary Health Care Sydney
KNEE PAIN
Updated May 2013
Outline
•
•
•
•
•
•
•
Knee pain and common causes
Differential diagnosis
Baker’s Cyst
Osgood-Schlatter Lesion
ACL & PCL
Examination
Investigations
Knee Pain
•
•
•
•
•
•
•
Knee pain is a common presenting complaint with many possible causes.
Teenage girls and young women: more likely to have patellar tracking problems
such as patellar subluxation and patellofemoral pain syndrome.
Teenage boys and young men: more likely to have knee extensor mechanism
problems such as tibial apophysitis (Osgood-Schlatter lesion) and patellar
tendonitis.
Older adults: Osteoarthritis of the knee joint is common.
Referred pain resulting from hip joint pathology, such as slipped capital femoral
epiphysis, also may cause knee pain.
Active patients: more likely to have acute ligamentous sprains and overuse
injuries such as pes anserine bursitis and medial plica syndrome.
Trauma: may result in acute ligamentous rupture or fracture, leading to acute
knee joint swelling and hemarthrosis. Septic arthritis may develop in patients of
any age, but crystal-induced inflammatory arthropathy is more likely in adults.
Common Causes of Knee Pain
by Age Group
Children and Adolescents
Adults
Older Adults
Patellar subluxation
Patellofemoral pain
syndrome
(chondromalacia patellae)
Osteoarthritis
Tibial apophysitis
(Osgood-Schlatter lesion)
Medial plica syndrome
Crystal-induced
inflammatory arthropathy:
gout, pseudogout
Jumper's knee (patellar
tendonitis)
Pes anserine bursitis
Popliteal cyst (Baker's
cyst)
Referred pain: slipped
capital femoral epiphysis
Trauma: ligamentous
sprains (anterior cruciate,
medial collateral, lateral
collateral), meniscal tear
Osteochondritis dissecans
Inflammatory arthropathy:
rheumatoid arthritis,
Reiter's syndrome
Septic arthritis
Causes of Acute Knee Pain
Common
Less Common
Not to be missed
Medial Meniscus Tear
Patellar tendon rupture
Fracture of the Tibial
Plateau
MCL Sprain
Acute Patellofemoral Joint
Injury
Avulsion fracture
ACL rupture
Coronary Ligament Sprain
Osteochondritis Dissecans
Lateral Meniscus Tear
Bursal hematoma /
bursitis
Reflex Sympathetic
Dystrophy (post injury)
Articular Cartilage Injury
Acute fat pad
impingement
PCL Sprain
Low Quadriceps
Haematoma
Patellar Dislocation
Avulsion of Biceps Femoris
Tendon
Dislocated Superior
Tibiofibular Joint
Surrounding Musculature
• Muscles surrounding the knee joint further
contribute to knee stabilization during lower
extremity movements
• Primary muscles include the quadriceps anteriorly,
hamstrings posteriorly, gluteus medius and tensor
fascia lata/IT band laterally and the hip adductors
medially
• The repetitive, eccentric nature of muscular activity
about the knee during sports may lead to fatigue
related injuries
Differential Diagnosis of Knee
Pain by Anatomic Site
Anterior Knee Pain
Posterior Knee Pain
Patellar subluxation or dislocation
Popliteal cyst (Baker's cyst)
Tibial apophysitis (Osgood-Schlatter
lesion)
Posterior cruciate ligament injury
Jumper's knee (patellar tendonitis)
Patellofemoral pain syndrome
(chondromalacia patellae)
Differential Diagnosis of Knee
Pain by Anatomic Site
Medial Knee Pain
Lateral Knee Pain
Medial collateral ligament sprain
Lateral collateral ligament sprain
Medial meniscal tear
Lateral meniscal tear
Pes anserine bursitis
Iliotibial band tendonitis
Medial plica syndrome
The Relationship of Swelling
to Diagnosis
Immediate
Delayed
0-2 Hours
6-24 hours
(hemarthrosis) (effusion)
No Swelling
ACL rupture
Patellar
Dislocation
MCL Sprain
Meniscus
Baker's Cyst
Baker’s Cyst
 Definition: A Chronic Knee Joint effusion
 A Baker cyst, also called a popliteal cyst, is a synovial
cyst located posterior to the medial femoral condyle
between the tendons of the medial head of the
gastrocnemius and semimembranosus muscles. It
results from the abnormal collection of fluid inside
the gastrocnemio-semimembranosus bursa.
 A Baker cyst is lined by a true synovium, as it is an
extension of the knee joint.
 Popliteal cysts range from 1-40 cm3 (median 3 cm3).
Symptoms of Baker’s Cyst
Symptoms
Frequency
Frequency
Popliteal Mass or Swelling
29/38
76%
Aching
12/38
32%
Knee Effusion
12/38
32%
Thrombophlebitis
5/38
13%
Clicking of the knee
4/38
11%
Buckling of the knee
4/38
11%
Locking of the knee
1/38
3%
Popliteal Mass
 The most common presenting complaint or symptom
 It is usually visible as a bulge behind the knee, which is
particularly noticeable on standing and comparing to the
opposite uninvolved knee. They are generally soft and minimally
tender
 Baker cysts can become complicated by protrusion of fluid down
the leg between the muscles of the calf (dissection). The cyst
can rupture, leaking fluid down the medial leg to sometimes give
the medial ankle the appearance of a painless bruise. Baker cyst
dissection and rupture are frequently associated with swelling of
the leg and can mimic phlebitis of the leg
Phlebitis in the Leg
• Inflammation of a vein, leading to the formation of a
thrombus in the vein
• Will cause the leg to swell with oedema fluid and feel
stiff and painful
• Significant number of patients (13%) have symptoms
simulating deep venous thrombosis (DVT), a
syndrome termed pseudothrombophlebitis
• Therefore, exclude DVT in patients with popliteal cyst
and leg swelling
Medical Conditions Associated
with Popliteal Cysts
Medical conditions associated with popliteal cysts, in descending
order of frequency, are as follows:
 Arthritides: Osteoarthritis, RA, Juvenile RA, Gout, Reiter
syndrome, psoriasis & systemic lupus erythematosus.
 Internal derangement: meniscal tears, ACL tears, osteochondral
fractures
 Infection: septic arthritis, tuberculosis
 Chronic dialysis
 Hemophilia
 Hypothyroidism
 Pigmented villonodular synovitis
 Sarcoidosis
Baker’s Cyst & Arthritis
• Arthritis is the most common condition associated with Baker
cyst. Of the arthritides, osteoarthritis is probably the most
common cause of popliteal cyst. Although prevalence of Baker
cyst in patients with inflammatory arthritis is higher than in
patients with osteoarthritis, osteoarthritis is much more
common than inflammatory arthritis.
• Fam et al demonstrated that the occurrence of Baker cysts
relates directly to the presence of knee effusion and severity of
osteoarthritis.
• In 99 consecutive patients with RA, Andonopoulos et al
demonstrated Baker cysts on US in 47 patients (48%). Twenty
patients (20%) had bilateral cysts. Of 198 patients' knees, 67
(34%) had popliteal cysts, yet only 29 cysts (43%) were
diagnosed clinically.
Diagnosis of a Baker’s Cyst
 Arthrography (a type of x-ray examination that uses a
contrast agent to image an anatomical joint): 5-46%
 Ultrasound: 40-42%
 Arthoscopy: 37%
 Cadaveric dissections 30%
 MRI 5-18%
Treatment of Baker’s Cyst
 Often no treatment is necessary and the practitioner can
observe the cyst over time. If the cyst is painful, treatment is
usually aimed at correcting the underlying problem, such as
arthritis or a meniscus tear.
 Baker cysts often resolve with removal of excess knee fluid in
conjunction with cortisone injection.
 Medications are sometimes given to relieve pain and
inflammation.
 When cartilage tears or other internal knee problems are
associated, surgery can be the best treatment option. During a
surgical operation the surgeon can remove the synovium that
leads to the cyst formation.
Patellofemoral Pain Syndrome
(Chondromalacia patellae)
 Patellofemoral Syndrome is the term used to describe pain in
and around the patella
 Functional Anatomy
 Full extension: Patella sits lateral to the trochlea
 During Flexion: Patella moves medial and comes to lie within
the intercondylar notch until 130º, when it starts to move
lateral again.
 Patella excursion is controlled by the quadriceps, particularly
VMO & VL
 With increasing knee flexion, a greater area of patellar articular
surface comes into contact with the femur, therefore offsetting
the increased load that comes with flexion
Patellofemoral Pain Syndrome
Cont.
Loaded knee flexion activities subject the
patellofemoral joint to loads many times the body
weight.
Activity
Level Walking
Going up stairs
Force through PFJ
0.5 x body weight
3-4 x body weight
Squat
7-8 x body weight
Anatomically, the lateral structures of the PFJ are much
stronger than the medial structures, so any
imbalance in the forces will cause the patella to drift
laterally.
Predisposing Factors
Factors
Cause
Abnormal Biomechanics
Excessive Pronation
Femoral anteversion (internal
femoral torsion)
High small patella (patella alta)
Increased Q angle
Soft tissue tightness
Muscles: Gastroc, H’strings, Rec Fem
& ITB
Lateral Structures: Lateral
retinaculum, ITB & VL
Muscle Dysfunction
VMO
Hip abductors / External rotators
(glut med)
Training
Distance running
Hills, stairs
Tibial Apophysitis (OsgoodSchlatter Lesion)
• The typical patient is a 13- or 14-year-old boy (or a
10- or 11-year-old girl) who has recently gone
through a growth spurt.
• Aggravated by:
– Squatting
– Walking up / down stairs
– Forceful contraction of the quadriceps
– Exacerbated by jumping and hurdling, because
repetitive hard landings place excessive stress on
the insertion of the patellar tendon.
Anterior & Posterior Cruciate
Ligaments
 Two important intra-articular ligaments that provide static support to the knee
are the anterior (ACL) and posterior (PCL) cruciate ligaments. The PCL and ACL
are intra-articular but extrasynovial
 The ACL originates from the medial and anterior aspect of the tibial plateau and
runs superiorly, laterally, and posteriorly toward its insertion on the lateral
femoral condyle
 The ACL is composed of the anteriomedial and posteriolateral bundles. Together,
these bundles provide approximately 85% of total restraining force of anterior
displacement of the tibia on the femur
 To a lesser degree, the ACL checks extension and hyperextension. Together with
the posterior cruciate ligament (PCL), It also prevents excessive tibial medial and
lateral rotation, as well as varus and valgus stresses
 The ligaments are tense in all positions, but increase their tension in the
extremes of flexion and extension
Anterior Cruciate Ligament
 The anterior cruciate ligament (ACL) is one of the
most commonly injured ligaments of the knee. Each
year, approximately 100,000 people sustain ACL
injuries with basketball, soccer, skiing, and gymnastics
being the sports with the highest incidence
 ACL injury rates are estimated to be two to eight
times higher in females than males participating in
the same sports
 Numerous studies exploring why females are at a
higher risk cite both intrinsic and extrinsic differences
between genders
Anatomy and Biomechanics
1.
2.
3.
Smaller notch width index. A smaller notch width index has been
found to predispose females to ACL injuries. The smaller notch likely
causes a shearing effect on the ACL by the femur. Although this
smaller, A-shaped notch has been shown to be related to ACL
injuries, there is no evidence that the relationship is causal
Increased ligamentous laxity. Females in general have ligaments that
are more lax than males, which increases the risk of ACL rupture. In
addition, it has been suggested that within the first year after surgery
when “ligamentization” of the tendon occurs, females undergo a
different remodeling response than males
Increased Q angle. The female pelvis is wider than the male pelvis,
which increases the Q angle of the knee. This leads to increase
stresses at the knee, and causes other compensatory deviations in
the surrounding joints. Other changes that occur include femoral
anteversion, tibial external torsion, and subtalar pronation
Neuromuscular Imbalances
 Research has shown disparity among females and males in knee
proprioception and neuromuscular control
 Quadriceps dominance pattern. Females demonstrate strength
imbalance between quadriceps and hamstrings. Female athletes tend
to rely on their quadriceps and gastrocnemius and less on their
hamstrings when compared to males. In addition, females exhibited a
delayed firing pattern of the hamstrings
 Landing strategies. Females use different strategies when running,
landing, or jumping than males and tend to land with an increased
valgus moment. This may cause significant differences between their
dominant and non-dominant knee. However, both knees may
potentially be at an increased risk for ACL rupture. The dominant knee
works to limit gravitational forces, while the non-dominant knee may
be too weak to withstand such forces
Hormonal Influences
• Female hormones have been suggested as a
possible risk factor for ACL rupture. It has
been hypothesized that these hormones
increase ligament laxity and decrease
ligament strength during the weeks prior to
and immediately following the menstrual
cycle.
• However, further research is needed to
confirm or deny the role of female sex
hormones in ACL injury.
Mechanism of Injury
 The ACL is usually torn as a result of a quick
deceleration, hyperextension or rotational injury that
usually does not involve contact with another
individual. This injury often occurs following a sudden
change of direction
 When hit from the side, injuries to the ACL are often
associated with medial meniscus and medial
collateral ligament (MCL) tears, collectively known as
the “unhappy triad.”
 In adolescents, the ACL may avulse from the tibial
spine instead of rupturing
Signs and Symptoms
 An acute ACL rupture is characterized by pain, hemarthrosis, and
instability. At the moment of injury, many people report hearing or
feeling a popping sensation
 Common impairments typically include immediate swelling (0-2 hours),
decreased strength and range of motion, inability to weight-bear and
poor balance and coordination
 Considerable pain in the knee that does not go away within the first few
hours after the injury
 Patients are functionally limited in their ability to ambulate, negotiate
stairs, and perform basic and instrumental ADLs. If not properly
addressed, these impairments could become chronic conditions
 A feeling of unsteadiness and a tendency for the knee to "give-way," or
an inability to bear weight on the injured leg
 An audible "pop" or the perception of something snapping or breaking
at the moment of injury
 A feeling of "fullness or tightness" in the knee
Examination








Observation: Standing, walking & Supine
Active Movements: Flexion & Extension
Passive Movements: Flexion & Extension
Palpation: PFJ, MCL, LCL, Medial & Lateral Joint line,
& in prone (hamstring tendons, Bakers Cyst, Gastroc origins)
Special tests
Presence of Effusion
Stability tests: MCL, LCL
 ACL: Lachmans test, Anterior drawer test & Pivot shift test
 PCL: Posterior Sag, reverse Lachmans test & posterior drawer
test
 Flexion / Rotation (McMurrays test)
 Patellar Apprehension Test
 PFJ
Investigations: X-ray
• The specific indications for x-ray following
acute knee injury are:
• High speed injuries (suspect a tibial plateau
fracture
• Children or adolescents (who may avulse a
bony fragment instead of tearing of a cruciate
ligament)
• If there is clinical suspicion of loose bodies
• If hemarthrosis is present
• If surgery is indicated