The Knee: Injuries
Objectives

Identify pathologies that occur in the knee, differentiating their signs & symptoms

Bony pathologies
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Ligamentous pathologies
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Musculotendinous pathologies
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Other structural/functional pathologies
Structural Malalignments
Leg alignment
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Genu valgum –
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Genu varum – bow-legged
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Genu recurvatum – Hyperextension
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Patella alta – high patella
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Patella baja – low patella
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Squint eye patella – points
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Frog eye patella – points laterally
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Q-angle – degree of valgus alignment between anterior hip & tibia
Skeletal pathologies
Knee fractures
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Femur, Tibia, Fibula o Diaphysis o o Avulsion
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Epiphyseal fractures o Skeletally immature o o Proximal tibia or fibula
Osteochondral defect
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Fracture of o Can involve the underlying bone
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MOI: & shear force
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Medial & Lateral femoral condyle, tibial articulating surface, & patella
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S&S: o Diffuse pain, “ ,”
“popping,” “clunking,” “giving way” o “ ” o Often mimics meniscal tears
Patellar fractures

Relatively rare o MOI: Direct trauma; rapid flexion force; eccentric load o May or may not require surgery o Can be acute or stress related
Chondromalacia Patella

Degeneration of

Chronic condition
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Possible predisposing factors o Recurrent subluxations or dislocations o Direct trauma
Notes
 o Patellar malalignment
Often involves

Pain after prolonged sitting (“movie sign”)
Traction apophysitis

Defined as: of a large tendon that causes damage to the unfused apophysis
(junction) to which it is attached

Can occur at any site where tendon attaches to bone
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Common in two places in the knee o o Sinding-Larsen-Johansson
Osgood-Schlatter disease

Most common growth related knee pain in young people o Rapid growth, increased strength, or both

Repetitive traction on

Minor avulsion at tibial tuberosity o Leads to inflammatory reaction
Sinding-larsen-johansson disease
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Inflammation at the of the patella resulting from avulsion or stress fracture o Repetitive traction on inferior patella

Common in skeletally immature individual & males
Soft tissue pathologies
Sprains

Lateral collateral (LCL) o force or internal rotation of tibia o Relatively uncommon o May involve ACL or PCL o Be aware of secondary avulsion injury to fibular head

Medial collateral (MCL) o force or external rotation of tibia o May be contact or non-contact injury o Often involve medial meniscus and/or
ACL o Must be wary of patellar dislocations with valgus force

Posterior cruciate (PCL) o Tibia hyperext or hyperflex o Often involves edema o Mechanism 

Anterior cruciate (ACL) o Tibia
on femur,
on femur, rotation of tibia, & w/ o Many are non-contact injuries o Often involves a “ ” & edema

The Knee: Injuries o Be aware of secondary injuries o o Know predisposing factors!

Potential ACL Injury Components high velocity force
Tibiofemoral dislocations

Direction, complete/partial, open/closed, low or
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Severe pain, spasm, and deformity o Consider if 3 of ACL, PCL, MCL, or LCL are damaged without deformity

Probable (~30%) pathology to vessels and nerves o Consider if these symptoms are present w/out deformity o MUST o Medical emergency
Patellar dislocation/subluxation

May be described as “just gave out”

Acute or chronic; more common in females
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Tight lateral tissues, weak medial musculature,
↑ Q-angle

MOI:
(~20-30°) and external rotation of tibia o May involve avulsion fracture or muscle tearing o May involve MCL tear; consider effect of
ACL
Meniscal tears

Typically caused with o Varus or valgus forces
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May be chronic or acute
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Type – based on orientation & etiology of defect
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Lateral meniscus tears o Often ; often secondary to repeated stress o Can go undetected

Medial meniscus tears o Firm fixation and attachment to o More likely to be torn?

S & S: o o Joint line pain, effusion o May or may not involve pain
Patellar tendonitis

Typically a chronic injury w/ insidious onset o May start with acute trauma
Notes o Moderate to severe pain w/
= better indicator than mild pain
Quadriceps tendonitis

Typically a chronic injury w/ insidious onset o May start with acute trauma o Moderate to severe pain w/
= better indicator than mild pain
Bursitis

13 bursae commonly around the knee joint
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MOI: o Be aware of infection
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Swelling may be extreme (“water on the knee”)
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Onset may be acute or chronic
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Most common bursitis in athletes o Prepatellar o Infrapatellar o o Deep infrapatellar o Anserine & Semimembranosus
IT band friction syndrome

Often seen in runners, cyclists, rowing o Often seen when “over-striding” o Running downhill, going down stairs, etc.
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Inflammation as I-T Band repeatedly crosses over

Often associated with tight or inflexible IT Band

Typically chronic, insidious onset o Repetitive microtrauma of knee flex/ext o May develop bursitis or periostitis

S&S: o “ ”; often radiates distal from lateral femoral condyle o Pain w/ knee flexion & extension o May describe “popping” sensation o General IT band tightness
Patellofemoral pain syndrome

Catch all term involving abnormal

Malalignment & instability issues present

Chondromalacia patella

Lateral tracking of patella o Tight hamstrings & gastrocnemeus o Increase Q angle o Tight & lateral patellar tissues o Patella alta or baja o ______ weakness or imbalance compared to vastus lateralis o Weak hip adductors o Change in footwear, surface, activity level/intensity