Knee Fx Flashcards
imaging
Arthrogram:
Great for looking for tears in soft tissue inside and around a joint (cartilage/ menisci, labrum, tendons, ligaments, etc), often combined with CT/MRI
imaging
PET scan and bone scan
Used for monitoring all bones at once to see if there are multiple lesions; images are typically not very specific; PET can be used in a specific location or entire body and often combined with CT or MRI
PET scan monitors general metabolic activity with a tracer
Bone scan monitors osteoblast activity with a tracer (new bone formation)
MRI and CT
MRI : Great for soft tissue and bone changes (infection, inflammation, necrosis, etc); taken in slices like CT; can be distorted by metal
CT : Great for seeing bone and alignment issues in multiple slices; can result in 3-D reconstruction; not great for soft tissue
Knee: Osteochondritis Dissecans (OCD)
etiology and common complaints
Etiology:
Subchondral necrosis and collapse with cartilage damage (AVN but on a smaller scale)
Hereditary, traumatic, or vascular in nature
Common symptoms/complaints:
Knee pain with locking/ popping
Knee: Osteochondritis dissecans
PE and test
Physical Exam:
Localize joint line tenderness
Occasionally will have effusion
Occasionally will have popping
Tests: start with X-Rays (knee – notch view) but MRI is needed to determine severity
Knee: Osteochondritis dissecans
Tx and pearls
Treatment:
Kids: more conservative tx like rest, cast, NWB x several months
Adults: stable – weight bearing restrictions, unstable surgical repair – drilling, screw fixation, resurfacing, joint replacement
Both require surgical removal if there is a loose body in the joint
Pearls:
Most common location of OCD in the knee is the posterior lateral aspect of the medial femoral condyle (70%), capitellum of humerus, talus
Knee: Bipartite Patella
etiology anf complaints
Etiology: lack of fusion of patella at growth area; results in patella that is in multiple pieces
Typically, only hurts if there is repetitive trauma but patient cannot recall a specific injury
Incidental finding on radiograph
Common symptoms/ complaints:
Typically, asymptomatic
Sometimes pain resulting from trauma
Knee: Bipartite Patella
PE and tests
Physical Exam:
TTP over patella if inflamed; otherwise, unremarkable
Tests:
X-rays: edges will often not be as sharp as fractures
MRI can help to visualize inflammation
Knee: Bipartite Patella
Tx and pearls
Treatment:
Rest
Immobilization
Physical Therapy
Sometimes fixation is needed (treat it like a fracture)
Pearls:
Bilateral in 50% of patients with the disease
Knee: Patellar Instability
etiology and presentation
Etiology:
Medial or lateral subluxation or dislocation of patella; often related to loose or torn retinaculum (MPFL) or muscle weakness
Presentation:
Depends on severity of injury
Pain, swelling, “kneecap popped out of socket”
Non-contact twisting injury w/ knee & foot externally rotated
Knee: Patellar Instability
PE and Dx
PE:
Chronic: sometimes can manipulate patella to sublux – patellar translation
Acute: Traumatic Effusion
If dislocated, it will be visible
TTP at medial* or lateral edge of patella
Diagnosis:
X-rays and MRI to see location, inflammation, loose bodies, MPFL tears
Knee: Patellar Instability
Tx
Treatment:
Depends on severity
Obviously needs to be reduced if dislocated
PT for quad strengthening – 6 weeks
Rest
Surgical repair
MPFL repair/reconstruction
Tibial tubercle distalization
Knee: Patellar Tendon Rupture/ Quad Rupture
Etiology and complaints
Etiology:
Tension overload during activity (flexed or overload of extensor mechanism)
Quad tendon 2x more likely than patellar ligament rupture
Risk factors: previous injury, steroid injection, DM, SLE, RA, renal disease (weakening of collagen)
Common symptoms/ complaints:
Felt/hear a pop and noticed immediate visible abnormality
“Jumper’s knee” – sudden quad contraction with knee flexed
Knee: Patellar Tendon Rupture/Quad Rupture
PE and Tests
Physical Exam:
Patella – difficulty w/ knee flexion, patella alta
Quad – difficulty with straight leg raise, can’t extend knee, sulcus sign noted, patella baja
Possibly will have swelling and bruising
Hemarthrosis
Tests:
X-rays will show abnormal patellar positioning
MRI confirms tendon rupture – complete vs partial
Knee: Patellar Tendon Rupture/ Quad Rupture
PE and Tests
Treatment:
Immobilization in KI
Conservative tx w/ intact extensor mechanism
Operative: surgical repair of tendon – suture anchor, end to end, graft
Pearls:
Quad more often in over 40 y.o. patients
Patellar more often in under 40 y.o. patients (30-40yo)
Complications: knee stiffness/re-tear
Knee: Prepatellar Bursitis
Etiology and common complaints
Etiology:
Bursa anterior to the patella becomes inflamed due to overuse or direct trauma
Commonly in patient’s who do excessive kneeling – concrete, flooring
20% septic bursitis
“Housemaid’s knee”
Common symptoms/ complaints:
Pain, anterior swelling, mostly normal ROM
Knee: Prepatellar Bursitis
PE and tests
Physical Exam:
Prepatellar edema
Fluctuance, +/- TTP over patella
Near full AROM
Tests:
Aspiration if concern for septic pre-patellar bursitis
X-Ray knee r/o joint effusion
Knee: Pes Anserine Bursitis
Etiology and common complaints
Etiology: inflammation of the pes anserine bursa
Remember it is deep to the gracilis, sartorius, and semitendinosus tendons at the lower medial knee
Common symptoms/ complaints:
Localized pain medial knee just below joint line
Mild swelling occasionally
Commonly seen in runner (hills/stairs)
Knee: Pes Anserine Bursitis
PE and tests
Physical Exam:
Medial knee pain just 2-3cm below the joint line
Tests: Clinical findings
Knee: Baker’s Cyst (popliteal)
etiology and common complaints
Etiology:
Cyst forms (like a ganglion cyst) on the back of the knee (either from the joint or from one of the posterior tendon sheaths)
Commonly associated with intraarticular knee disorders (OA, meniscal tears due to excessive fluid formation)
Common symptoms/ complaints:
Swelling
Trouble with flexion
Not really painful
Knee: Baker’s Cyst
PE and Tests
Physical Exam:
No effusion of knee
Palpable “lump” due to localized swelling to posterior knee +/- swelling of lower leg
Reduced knee flexion
Tests:
MRI or ultrasound is absolutely needed to be sure it is not from a blood vessel (aneurysm)
Knee: Baker’s Cyst
Tx and pearls
Treatment:
Rest & monitor
Modify activity
Aspiration and steroid injection
Surgical excision if painful, compressive vascular structures or conservative approach fails
Pearls:
Like other cysts, it might return
Knee: ACL Tear
Etiology and presentation
Etiology:
Tear of ligament, usually because of twisting injury or direct blow to the knee
Often because of sport injury – basketball. soccer
Presentation:
Pain deep in knee (not always)
Instability
“Pop” in the knee
Immediate swelling/effusion
Knee: ACL Tear
PE and tests
Physical Exam:
Effusion
Little to no TTP
+ Lachman
+ Anterior drawer
“Quadriceps avoidance” – do not want to extend the knee
Tests:
MRI
Lachman +
Anterior drawer test +
Knee: ACL Tear
Tx
Treatment:
Almost always need surgical repair (unless older and inactive)
- Femoral/tibial tunnel, graft fixation
- Bone-Patella-Bone autograft*, quad tendon/ham autograft, allograft
- Repair associated damaged structures (meniscus/MCL)
ACL brace during recovery controversial
Physical therapy after surgery
Pearls:
Often associated with MCL or medial meniscus injury (50%)
Knee: PCL Tear
etiology and presentation
Etiology:
Tear of the PCL related to hyperextension or direct blow to flexed knee (dashboard or athletic injuries)
Presentation:
Posterior knee pain, instability, swelling
Knee: PCL Tear
PE and tests
Physical Exam:
Pain w/effusion
Feeling of instability with posterior movement
+posterior drawer
+sag sign
Tests:
MRI
+ posterior drawer test
Knee: MCL Tear
Etiology and common complaint
Etiology:
Forceful valgus stress to lateral aspect of the knee (direct lateral blow to knee)
Most common ligamentous injury
Common in athletes – skiing, rugby, soccer, football
Common symptoms/ complaints:
Pain at medial knee
Instability
Edema
Knee MCL tear
PE and Tests
Physical Exam:
Effusion
Ecchymosis
Medial joint line TTP
Instability with valgus stress
Tests:
MRI
+Valgus stress test
Knee: LCL Tear
Etiology and presentation
Etiology:
Varus stress to the medial knee tears the LCL
Traumatic blow to medial knee
Most often seen in gymnasts and tennis players
Presentation:
Pain/swelling along lateral knee
Instability near full knee extension – difficulty using stairs & cutting/pivoting
Swelling
Knee: LCL Tear
PE and test
Physical Exam: Effusion
TTP over lateral joint line of knee
Effusion
Ecchymosis
Pain with varus stress
Tests: MRI – most tears are the fibular insertion
+ Varus stress test
Knee: Lateral or Medial Meniscus Tear
etiology and presentation
Etiology:
Tear of the cup-like structure as a result of twisting or deep squat
Acute sports injuries in younger patient Degenerative condition in older population
Medial more common (except in ACL tears)
Presentation:
Pain
Clicking/locking/pop
Knee “giving out” sensation
Delayed/intermittent swelling
Knee: Lateral or Medial Meniscus Tear
PE and tests
Physical Exam:
Vague localized pain at joint line
Delayed swelling
+McMurray test
Otherwise fairly normal
Can occasionally get popping/locking reproducible when squatting
Tests:
MRI
Knee: Lateral or Medial Meniscus Tear
Tx
Treatment:
Conservative: Rest, NSAIDs, PT
Operative: if symptoms do not resolve or tear is very large
Arthroscopy can be therapeutic and diagnostic
Repair for large tears in outer third; debridement for other tears
Knee: Chondromalacia Patella
etiology and complaints
Etiology:
Breakdown of the cartilage on the back of the patella and in the patellofemoral groove
Limb malalignment, muscle weakness, patella maltracking
Common symptoms/ complaints:
Anterior knee pain with activity (especially squatting, prolonged sitting, and stairs)
Knee: Chondromalacia Patella
PE and Tests
Physical Exam:
Peripatellar pain with patellar compression
Insidious (vague) onset
Patellar maltracking with ROM
Crepitus with flexion and extension
Tests: Clinical exam, radiographic findings: sunrise to show abnormal tracking, MRI to assess articular cartilage
