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Year 2 Clinical > Soft Tissue Knee Injuries > Flashcards

Soft Tissue Knee Injuries Flashcards

1
Q

Function of menisci?

A

Distribute load from the convex femoral condyles to the relatively flat tibial articular surfaces

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2
Q

Differences between medial and lateral menisci?

A

Medial plateau is more concave and the medial meniscus is fixed whilst LATERAL MENISCUS is MORE MOBILE

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3
Q

Briefly describe movement of the knee joint

A

Due to shape and soft tissues, knee pivots on medial compartment, through flexion and extension

Tibia internally rotates on flexion and externally rotates on extension

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4
Q

Which meniscus is under the greatest amount of shear stress?

A

Medial meniscus

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5
Q

Ligaments of the knee and their functions?

A

Medial collateral ligament (MCL) - resists valgus stress

Lateral collateral ligament (LCL - resists varus stress

Anterior cruciate ligament (ACL ) - resists anterior subluxation of the tibia and INTERNAL ROTATION OF THE TIBIA IN EXTENSION

Posterior cruciate ligament (PCL) - resists posterior subluxation of the tibia, i.e: anterior sublixation of the femur and hyperextension of the knee

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6
Q

Describe the posterolateral corner of the knee

A

PCL and LCL with popliteus and other smaller ligaments resist external rotation of the tibia in flexion

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7
Q

Consequences of rupturing the different ligaments of the knee?

A

MCL rupture - valgus instability

ACL rupture - rotatory instability

PCL rupture - recurrent hyperextension or instability descending stairs

Posterolateral corner rupture - varus and rotatory instability

Multi-ligament injury - gross instability

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8
Q

Meniscal tears scenarios?

A

Younger patient - sporting injury or getting up from a squatting position; also, half of ACL ruptures are accom. by a meniscal tear

Older patients (>40 years) - can get atraumatic spontaneous degenerate tears

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9
Q

Ix for meniscal tear?

A

MRI - menisci should be uniform black triangle (look like a bow-tie); there should be no lines within the triangles

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10
Q

Which meniscus tears most commonly?

A

Medial meniscal tears are 10X more common

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11
Q

Why do meniscal tears have limited healing potential?

A

Only the peripheral third of the menisci have a blood supply, i.e: radial tears will not heal

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12
Q

Management options of meniscal tears?

A

Acute peripheral tears in younger patients - arthroscopic repair can be considered with extensive rehab (40% failure rate)

For mechanical symptoms (painful catching/locking) in irreparable tears or failed meniscal repair - arthroscopic menisectomy

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13
Q

Patterns of different meniscal tears?

A

Longitudinal tear (if near the edge, it may heal)

Bucket handle meniscal tear

Radial tear (will not heal)

Parrot beak tear

ADD IMAGE MENISCAL TEARS

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14
Q

Describe the presentation of a bucket handle meniscal tear

A

ACUTE LOCKED KNEE signifies a displaced bucket handle meniscal tear; patient will also have a 15 degree springy block to extension (unable to straighten leg)

If the knee remains locked, they may develop a fixed flexion deformity (AKA flexion contracture - unable to straigthen leg)

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15
Q

Management of a bucket handle meniscal tear?

A

Urgent surgery required as, if the knee remains locked, they may develop a fixed flexion deformity

If irreparable, the patient needs a partial menisectomy to unlock the knee and prevent further damage

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16
Q

In a bucket handle meniscal tear, what causes the locked knee sign?

A

Central fragment displaces into the intercondylar notch, causing mechanical locking of the knee joint

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17
Q

Describe degenerative meniscal tears

A

Common, although many are asymptomatic; may represent the 1st stage of OA

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18
Q

Management of degenerative meniscal tears?

A

Inflammation from initial onset may settle and many people improve within 3 months

Surgery is less successful, esp. if there is evidence of existing OA on X-ray; arthrosopic menisectomy tends to be unsuccesful and is only for an unstable tear with mechanical symptoms, not for pain only

Steroid injections may help

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19
Q

Grading of knee ligament injuries?

A

Grade 1 (sprain) - some fibres torn but macroscopic structure is intact

Grade 2 (partial tear) - disruption of some fascicles

Grade 3 (complete tear)

20
Q

Variation in ligament healing capabilities?

A

Some heal more than other and some stabilise over time:
• MCL tends to heal well, even if there is a complete tear, unless combo with ACL/PCL rupture; can use bracing, early motion and physiotherapy (surgery is rare) although pain takes several months to settle

21
Q

Scenario of ACL rupture?

A

Usually, a sporting twist injury, accompanied by a POP

Within a few hours, the knee swells with a haemarthrosis, as the ACL contains a blood vessel

22
Q

Management of ACL ruptures?

A

ACL reconstruction only, using:
• Autograft (with patellar tendon/hamstrings)
• Allograft (Achilles tendon)
• Synthetic graft

Also, ACL can be stuck to the PCL to give some stability, and physiotherapy can stabilise ACL deficient knees

23
Q

What is the ACL rupture rule of thirds?

A

1/3rd of people compensate and are able to function well

1/3rd can avoid instability by stopping certain activities

1/3rd do not compensate and have frequent instability or cannot get back to high impact sport

NOTE: older patients are more likely to compensate or avoid high impact sports

24
Q

Role of surgery in ACL rupture?

A

For rotatory instability that is not responding to physiotherapy; this allows rapid return to professional sport/high demand job

May be suitable for a adolescent/young adult that enjoys high impact sport

May also be used as part of a multi-ligament reconstruction

25
Q

Disadvantages of ACL rupture surgery?

A

Does not treat pain or prevent arthritis

The surgery only stops instability so, if there is none, there is no need to do surgery

26
Q

Complication of ACL reconstruction?

A
  • 10% failure rate
  • Infection
  • Stiffness
  • Graft vs donor site morbidiity
27
Q

Complications of ACL ruptures?

A

Most patients have X-ray changes evident of OA, within 10 years

28
Q

Describe LCL injuries

A

Uncommon and are due to varus and hyperextension; often occur in combo with PCL/ACL injury

It does not heal well and can cause varus and rotatory instability

29
Q

Complications of LCL injury?

A

High incidence of common peroneal nerve palsy so it causes foot drop

30
Q

Management of LCL injuries?

A

Complete rupture requires urgent repair within 2-3 weeks

If later, reconstruction (with hamstrings or other tendon)

31
Q

Presentation of PCL rupture?

A

Usually occurs with a direct blow to the anterior tibia, e.g: dashboard/motorbike, OR a hyperextension injury

Causes popliteal knee pain and bruising

32
Q

Management of PCL rupture?

A

Isolated PCL rupture (rare) do not require reconstruction

If there is instability (recurrent hyperextension or feeling unstable when going downstairs) OR if it is part of a multi-ligament knee injury, it usually requires reconstruction

33
Q

Describe knee dislocation

A

Usually caused by a serious, high energy injury with a high incidence of complications, e.g:
• Popliteal artery injury (tear, intima tera and thrombosis)
• Nerve injury (common peroneal nerve
• Compartment syndrome

34
Q

Treatment of knee dislocation?

A

Emergency reduction and checking of neurovasular status; if there are vascular concerns, require vascular surgery

Require temporary stabilisation of the knee and usually multi-ligament reconstruction

35
Q

Describe patellar dislocation and occurrence

A

More common than knee dislocation and is usually due to a rapid turn or direct blow

Increased incidence in females and adolescents; risk factors include:
• Ligamentous laxity
• Valgus knee
• Torsional abnormalities

36
Q

Consequences of patellar dislocation?

A

10% have recurrent dislocation

It may cause chondral or osteochondral injury

37
Q

Management of patellar dislocation?

A

Some may benefit from surgical stabilisation

38
Q

Describe how extensor mechanism ruptures can occur

A

Extensor mechanism consists of quadriceps muscle and tendon, the patella and tendon, and the tibial tubercle

Falling onto flexed knees with contraction of the quads

39
Q

Risk factors for extensor mechanism rupture?

A

Previosu tendonitis

Steroids

Chronic renal failure

Ciprofloxacin

40
Q

Signs of extensor mechanism rupture?

A

Unable to straight leg raise (SLR); if they can do this, EMR is unlikely

If they cannot SLR, check for a palpable gap

41
Q

Management of extensor mechanism rupture?

A

Require surgical repair

42
Q

Main mechanisms of injury for the presentations in this lecture?

A

MCL - valgus

ACL/meniscal injury - twisting

LCL - varus

PCL - dashboard/hyperextension

Meniscal tear - getting up from squatting

43
Q

Most common ligament injuries?

A

MCL is most common, followed by ACL

44
Q

Classic Hx of an ACL rupture?

A 
Football twist injury 
\+
POP and haemarthrosis
\+
Generalised pain (settles after a few days 
\+
Rotatory instability
45
Q

Classic Hx of a meniscal tear?

A 
Getting up from squatting and experiencing a sudden, sharp pain along the medial joint line
\+
Effusion
\+
Recurrent medial pain
\+
Catching +/- locking
46
Q

Difference between POP and CRACK?

A

POP - ligament rupture

CRACK - fracture

Year 2 Clinical (119 decks)

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