COMMON PATHOLOGIES OF THE KNEE
MCL sprain
What is it?
A sprain to the medial collateral ligament of the knee
Signs/Symptoms:
- Pain on the medial aspect of the knee
- Tenderness along the MCL from its origin below the adductor tubercle to the
insertion on the medial tibial flare
- Edema on medial aspect of knee
MOI:
- A valgus force to the knee
- External rotation of tibia
Treatment:
- RICE
- Reconstruction if completely torn
- Rehab/ Therapy
Diagnostic Tools:
- MMT: Decreased flexion and extension strength secondary to pain w/ flexion
being more painful than extension.
- Special Tests: Slocum drawer test for laxity of the anteromedial capsule
- Functional assessment: Increased pain during midstance phase of gait secondary
to femur internally rotating on tibia
- MRI
Return to Play Criteria:
- Pt. shows strong structural integrity in the joint
- Pt. can bear weight and withstand a valgus force w/o pain
- Bilateral comparison shows no abnormalities
- Pt. has full ROM w/o pain
ACL sprain
What is it?
A sprain to the anterior cruciate ligament of the knee joint
Signs/Symptoms:
- Pain within the knee joint, sometimes described as “pain” or “pop” under the
kneecap
- Effusion in suprapatellar region
- Ballotable patella (floating patella)
MOI:
- Rotation of the knee while the foot is planted, a blow that drives the tibia
anterior relative to the femur
- Hyperextension
Treatment:
- RICE
- Reconstruction if completely torn
- Rehab/ Therapy
Diagnostic Tools:
- Stress Tests: Lachman’s, Anterior Drawer, Prone Lachman’s
- Joint play: anterior glide of tibia on the femur, posterior glide of the tibia
Return to Play Criteria:
- Pt. shows strong structural integrity in the joint
- Pt. can bear weight and withstand a valgus force w/o pain
- Bilateral comparison shows no abnormalities
- Pt. has full ROM w/o pain
PCL sprain
What is it?
A sprain the posterior cruciate ligament of the knee
Signs/Symptoms:
- Pain within the knee joint radiating posteriorly
- Effusion may not be present initially but may develop over time
- Posterior sag of the tibia
- Tenderness may be elicited in the popliteal fossa if the sprain involves the
posterior capsular structures or popliteus muscle
MOI:
- Posterior displacement of the tibia on the femur
- Knee hyperextension
- Knee hyperflexion
Treatment:
- RICE
- Reconstructive surgery if completely torn
- Rehab/ Therapy
Diagnostic Tools:
- Stress tests: Posterior drawer, godfrey’s sign, external rotation test
- Joint play: posterior glide of the tibia, anterior glide of tibia
Return to Play Criteria:
- Pt. shows strong structural integrity in the joint
- Pt. can bear weight and withstand a valgus force w/o pain
- Bilateral comparison shows no abnormalities
- Pt. has full ROM w/o pain
LCL
What is it?
A sprain to the Lateral Collateral Ligament of the knee
Signs/Symptoms:
- Pain on the lateral joint line
- Swelling is localized
- Tenderness along the length of the LCL
MOI:
- Varus force placed on the knee or excess internal tibial rotation
Treatment:
- RICE
- Reconstructive surgery if completely torn
- Rehab/ Therapy
Diagnostic Tools:
- Stress tests: Varus laxity on complete extension indicates involvement of the
lateral capsular structures and possibly the cruciate ligaments
- Joint play: Tibiofibular joint play
- Special tests: Slocum drawer test
- Functional assessment: Antalgic gait secondary to pain
Return to Play Criteria:
- Pt. shows strong structural integrity in the joint
- Pt. can bear weight and withstand a valgus force w/o pain
- Bilateral comparison shows no abnormalities
- Pt. has full ROM w/o pain
Meniscus tear (Medial)
What is it?
Damage to the medial meniscus within the knee
Signs/Symptoms:
- Pain along medial joint line
- Knee may “give out”
- A “clicking” noise may be present
- Snapping or locking may be associated with a discoid meniscus
-
Crepitus along joint line
Meniscal cyst may be palpable
MOI:
- Tibial rotation, often in combination with knee flexion and/or a varus or valgus
stress
- Hyperflexion impinges the posterior horns; hyperextension impinges the
anterior horns
Treatment:
- RICE
- Possible surgery to repair
- Knee brace
- Rehab/ Therapy
Diagnostic Tools:
- Stress tests: The integrity of all the knee ligaments must be established
- Special tests: McMurray’s, Apley’s compression, Thessaly
Return to Play Criteria:
- Pt. performs full ROM w/o pain or abnormalities
- Pt. tests negative to all special tests
- Pt. can perform movements under the same intensity and stress level as the sport
they are returning to play w/o pain
Patella tracking deformity
What is it?
- Abnormal displacement of the patella
Signs/Symptoms:
- A dull ache around the knee cap
- Popping, grinding, slipping, or catching of the kneecap as the knee flexes
- Swelling in the knee
- “Buckling” or “giving away” of the knee
MOI:
- Weak surrounding muscles
- Stretched or weak patellar tendon
- Stretched quadriceps
Treatment:
- Surgery if severe enough
- Physical Therapy
- Brace to prevent translation of the patella
Diagnostic Tools:
-
Side-lying knee flexion
Supine lyinge with knee flexion
MMT
Return to Play Criteria:
- Pt. performs full ROM w/o pain or abnormalities
- Pt. tests negative to all special tests
- Pt. can perform movements under the same intensity and stress level as the sport
they are returning to play w/o pain
Chondromalacia
What is it?
- Injury to the cartilage beneath the patella
Signs/Symptoms:
- Knee pain that increases during walking up and down stairs
MOI:
- Overuse of the knee joint
Treatment:
- RICE
- Physical Therapy
- Possible Surgery
Diagnostic Tools:
- X-rays, CT scan, MRI
Return to Play Criteria:
- Pt. performs full ROM w/o pain or abnormalities
- Pt. tests negative to all special tests
- Pt. can perform movements under the same intensity and stress level as the sport
they are returning to play w/o pain
Patella tendonitis
What is it?
- Inflammation of the patellar tendon
Signs/Symptoms:
- Pain in the patellar tendon
- Sharp pain during physical activity
MOI:
- Repetitive trauma to the patellar tendon
-
Overuse of the quads
Treatment:
- RICE
- Progressive exercises
Diagnostic Tools:
- Palpation
- MRI
Return to Play Criteria:
- Swelling has reduced
- Pt. shows full ROM w/o pain
- Pt. can perform exercises of equivalent intensity as the sport they are returning
to
Pre-patellar Bursitis
What is it?
Inflammation of the pre-patellar bursa within the knee
Signs/Symptoms:
- Swelling over the patella
- Limited motion of the knee
- Painful movement of the knee
MOI:
- Repetitive trauma to the knee
- Overuse of the knee
Treatment:
- RICE
- Drainage of the bursa
Diagnostic Tools:
- Palpation
- MOI
- MRI
Return to Play Criteria:
- Swelling has reduced
- Pt. shows full ROM w/o pain
- Pt. can perform exercises of equivalent intensity as the sport they are returning
to
Joint Contusion
What is it?
-
A bruise to the soft tissue of the knee due to direct trauma
Signs/Symptoms:
- Pain, swelling, and tenderness in knee
- Discoloration at injury site
MOI:
- Direct blow
- Knee sprain or fracture
Treatment:
- RICE
- Walking crutches
- Elastic wrap around knee
Diagnostic Tools:
- Palpation
- X-ray, MRI, CT scan
Return to Play Criteria:
- The injured area is padded to prevent further injury
- Swelling has reduced
- Pt. shows full ROM w/o pain
- Pt. can perform exercises of equivalent intensity as the sport they are returning
to
Plica
What is it?
- Damage to the plica on the inner side of the knee (AKA synovial plica syndrome
Signs/Symptoms:
- Pain and irritation in the knee
- Localized inflammation
MOI:
- Trauma to the knee during flexion
- Overuse
Treatment:
- Rest
- Surgical removal of the plica
Diagnostic Tools:
- Physical Examination
- MRI
Return to Play Criteria:
- Symptoms have subsided and pain is gone
- Pt. shows full ROM w/o pain
- Pt. can perform exercises of equivalent intensity as the sport they are returning
to
Osgood Schlatter disease
What is it?
- Repeated avulsion fractures on the tibial tuberosity resulting in osteochondritis
Signs/Symptoms:
- Localized pain on the tibial tuberosity
- Pt.’s age
MOI:
- Increased strength in the quadriceps during bone growth resulting in an
avulsion fracture to the tibial tuberosity
Treatment:
- Rest or modified activity to avoid stress to the affected area
- Possible surgical excision of the tibial tuberosity
Diagnostic Tools:
- X-ray
- Tap test
- Compression test
Return to Play Criteria:
- Pt. gave injury proper amount of rest
- Pain no longer exists
- Pt. can perform exercise at equivalent intensities to the sport in which they
return to play
Runner Knee
What is it?
- Also known as patellofemoral pain syndrome
Signs/Symptoms:
- Pain in patellar area during flexion
- Pain worsens downhill or down stairs
- “clicking” or “giving out” of knee
-
Pain at medial retinaculum, odd medial facet, lateral facet, lateral femoral
condyle during palpation
MOI:
- Overuse
- Direct trauma
- Misalignment
- Foot pathology
- Weak thigh muscles
Treatment:
- RICE
- Stretching and strengthening of the quads
- Arch support
Diagnostic Tools:
- Stress test to rule out chronic tibiofemoral instability
- MMT: pain and weakness in quads
- Joint play: lateral patellar glide may be increased, medial patellar glide
decreased
- Special tests: Ober’s test for IT band tightness, Navicular drop test
Return to Play Criteria:
- Pt. gave injury proper amount of rest
- Pain no longer exists
- Pt. can perform exercise at equivalent intensities to the sport in which they
return to play
- Bilateral comparison is good
- Quads are strong and pain free
Patella Tilt
What is it?
- An anterior shift in the medial border of the patella
Signs/Symptoms:
- Pain on patella
- Inefficient quad strength during flexion
- Pain on lateral aspect of knee
MOI:
- Weak quads
- Foot pathology
- Tibial rotation
- Tight IT band
Treatment:
-
Readjust patella
Rehab
Diagnostic Tools:
- Ober’s test
- Navicular drop test
Return to Play Criteria:
- Patella is moved back to normal position
- Pt. has pain free full ROM
- Bracing or taping is applied as needed
Unhappy Triad
What is it?
- Injury to the ACL, MCL, and meniscus at one time
Signs/Symptoms:
- Pain in knee
- Stiffness and swelling
- Catching or locking of the knee
- Instability with twisting or side to side movements
- Restricted ROM
MOI:
- Valgus force to the knee
Treatment:
- ACL and meniscus surgery
- PCL can be rehabilitated thru time and immobilization
- Physical Therapy
Diagnostic Tools:
- Anterior drawer test, Apley’s compression test, Lachman’s test, slocum’s test,
- MRI
Return to Play Criteria:
- Pt. performs full ROM w/o pain or abnormalities
- Pt. tests negative to all special tests
- Pt. can perform movements under the same intensity and stress level as the sport
they are returning to play w/o pain
- Pt. wears a protective brace to prevent repeated injury
Bakers Cyst
What is it?
- A fluid-filled cyst that causes bulging and tightness behind the knee
Signs/Symptoms:
- Worsening pain during full flexion or extension
- Swelling behind knee
- Stiffness
- Texture similar to balloon filled with water
MOI:
- Inflammation of the knee joint from arthritis
- Cartilage tear
Treatment:
- Rest, Ice
- Physical Therapy
- Fluid drainage
- Medications
Diagnostic Tools:
- Ultrasound
- MRI
Return to Play Criteria:
- Swelling subsides
- Full ROM w/o pain
Osteochondritis Dessicans
What is it?
- Joint condition in which a piece of cartilage breaks of the bone and becomes free
floating
Signs/Symptoms:
- Pain in the knee
- Popping or locking
- Joint weakness
- Decreased ROM
- Swelling and tenderness
MOI:
- Reduction of blood flow to the affected bone
- Repetitive trauma that the affected area
- Genetic
Treatment:
- Surgery
- Therapy
- Rest
Diagnostic Tools:
-
X-rays
CT scan
MRI
Return to Play Criteria:
- The free floating cartilage has been removed
- Full ROM w/o pain
- Swelling has subsided
- Structural integrity in the knee is strong
Iliotibial band friction syndrome
What is it?
- Injury to the lateral thigh or IT band.
Signs/Symptoms:
- Stinging sensation
- Swelling of tissue over the femur
- Chronic pain
- Pain in knee where IT band inserts
MOI:
- Running on a banked surface
- Excessive uphill or downhill running
- Toed- in feet during cycling
- Hiking long distances
- Rowing
- High/low arches
- Supinated feet
- Bow legs
- Leg length discrepancy
- Muscle imbalance
Treatment:
- RICE
- Foam rolling the IT band
- Ultrasound
- IT band compression wrap
- McConnell’s taping
- Restoring the VMO
Diagnostic Tools:
- Patellar tracking
- Leg length discrepancy test
- MMT
Return to Play Criteria:
-
Pt. performs full ROM w/o pain or abnormalities
Pt. tests negative to all special tests
Pt. can perform movements under the same intensity and stress level as the sport
they are returning to play w/o pain
Pes anserine bursitis
What is it?
- Inflammation of the bursa at the pes anserine
Signs/Symptoms:
- Pain, swelling, and tenderness on medial knee
- Pain when arising from a seated position or at night
MOI:
- Acute trauma to the medial aspect of the knee
- Overuse
- Mechanical/ degenerative processes
Treatment:
- Ice
- Ultrasonography
- Electrical stimulation
- Rehab
- Surgery
Diagnostic Tools:
- Palpation
- MRI
- CT scan
Return to Play Criteria:
- Pt. performs full ROM w/o pain or abnormalities
- Pt. tests negative to all special tests
- Pt. can perform movements under the same intensity and stress level as the sport
they are returning to play w/o pain
Pre-patellar bursitis
What is it?
- Inflammation of the pre-patellar bursa superficial to the patella.
Signs/Symptoms
- Swelling, tenderness over patella
- Increased pain with knee flexion
MOI:
- Direct trauma to the patella
Patellar Tendonosis (jumper’s knee)
What is it?
- Inflammation of the patellar tendon
Signs/Symptoms
- Dull, achy pain along the tendon
MOI:
- Likely due to excessive, repetitive forces place on the patellar tendon (jumping)
- Overuse
Patellar Tenosynovitis
What is it?
- Inflammation of the inner synovial lining of the tendon sheath
Signs/Symptoms
- Pain in the tendon
MOI:
- Repetitive strain to the patellar tendon/ overuse
- Trauma, infection
Fractured Patella
What is it?
- Fracture of the patella or kneecap
Signs/Symptoms
- Severe pain around the patella
- Swelling
- Pain with knee ROM
- Deformed knee (fractured pieces floating)
- Tenderness with pressure on the kneecap
MOI:
- Direct Trauma
Hyper-extended knee
What is it?
- The knee is over extended beyond it’s normal range of motion
Signs/Symptoms
- Pain in the knee
- Feeling a “pop” at the time of injury
- Swelling
- Instability in the knee
MOI:
- Anterior blow to the knee or lower leg
Patellar dislocation/ subluxation
What is it?
-
Slipping (subluxing/dislocating) of the patella from the patellar groove of the
femur
Signs/Symptoms
- Swelling, pain, discoloration medially
- Sense of instability, apprehension
MOI:
- Direct medial or lateral blow to the kneecap
- Sudden twist of the leg with the foot planted
Fat pad impingement
What is it?
- Impingement of the infrapatellar fat pad between the femur and tibia
Signs/Symptoms
- Tenderness just distal to the patella and deep to the patellar tendon
- Genu recurvatum
- Swelling in the distal joint line
- Lateral tilt of the patella due to swelling
MOI:
- Direct trauma
Patellar Tendon rupture
What is it?
- A rupture of the patellar tendon between the patella and the tibia
Signs/Symptoms
- Pain in the patellar tendon
- Swelling
- Inability to extend knee
- Discoloration
MOI:
- Explosive knee extension (likely during a plyometric motion)
Peroneal nerve contusion
What is it?
- Also known as “drop foot” it is an injury to the peroneal nerve at the knee
Signs/Symptoms
- Inability to dorsiflex the foot at the ankle
- Pain, weakness, numbness,
- High-step walking (footdrop gait)
MOI:
- Spinal cord injury from underlying disease
- Joint dislocation/fracture
- Direct trauma
Tibial Torsion
What is it?
-
Internal or external rotation of the tibia during closed chain (weight bearing)
movements
Signs/Symptoms
- Toe-in gait
- Pain in the knee joint
- Frequent tripping or falling during walking
MOI:
- Genetic factors
- Exact cause is unknown
Fabella
What is it?
- A sesamoid ossification found in the lateral head of the gastrocnemius muscle
Signs/Symptoms
- Pain in the posterolateral region of the knee that is increased with full knee
extension
- Sharp pain, tenderness in region of the fabella
- Tingling, numbness, or dropfoot due to the fabella irritating the fibular nerve
MOI:
- unknown
(Starkey, Brown, Ryan, 2010)