Knee Pathologies Flashcards by Cameron McCloskey

Which three components make up the knee joint?

The medial compartment of the tibiofemoral joint
The lateral compartment of the tibiofemoral joint
The patellofemoral joint

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What is contained within the tibiofemoral joint and what is their function?

Fibrocartilaginous menisci

Act as shock absorbers and act to distribute load evenly

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What are the four main ligaments of the knee?

Anterior cruciate ligament
Posterior cruciate ligament
Medial collateral ligament
Lateral collateral ligament

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What is the role of the ACL?

Prevents abnormal internal rotation of the tibia

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What is the role of the PCL?

Prevents hyperextension and anterior translation of the femur

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What is the role of the MCL?

Resists valgus force

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What is the role of the LCL?

Resists varus force and abnormal external rotation of the tibia

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Early OA of the knee may be predisposed by which conditions?

Previous meniscal tears
Ligament injuries (esp. ACL deficiencies)
Malalignment

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Which treatment can help younger patients with isolated medial compartment OA?

Osteotomy of the proximal tibia

(high tibial osteotomy)

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When would knee replacement be indicated?

Substantial pain and disability

Failure of conservative management

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What is the treatment for younger patients who have isolated OA in either the medial or lateral compartment of the knee joint?

Unicompartmental knee replacement

(total knee replacement can be utilised if this fails)

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Meniscal injuries to the knee classically occur with what?

Twisting force on a loaded knee

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How does a patient with a meniscal injury present?

Localised pain to the joint line (medial or lateral)
Effusion the following day
Catching or locking sensation may be present
Feeling of knee giving way
Pain on tibial rotation (Steinmann’s test)

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Which type of meniscal injury (medial or lateral) is more common?

Medial meniscal injury

(it is more fixed and less mobile than its lateral counterpart)

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What causes true knee locking?

A significantly torn meniscus flipping over and becoming stuck in the joint line

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Knee locking is a clinical sign associated with which knee pathology?

Meniscal tear

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How is knee “locking” with other knee pathologies such as OA different from that of a meniscal tear?

There is only temporary difficulty in straightening the leg
It can spontaneously resolve
The patient may describe a specific manouvre they use to relieve the locking

This is known as pseudo-locking as it is not true locking

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What causes ACL ruptures?

High rotational force e.g. turning the body laterally on a planted foot

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What is usually felt during an ACL rupture which is characteristic?

A pop sound or feeling

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How does an ACL rupture present?

Haemarthrosis and swelling within an hour
Deep knee pain
Rotatory instability
Excessive anterior translation of tibia on anterior drawer test

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Valgus stress injuries usually tear what?

MCL

(high forces can also damage the ACL)

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Which type of fracture can occur with valgus stress injuries?

Lateral tibial plateau fracture

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How is the PCL most commonly ruptured?

Direct blow to the anterior tibia whent he knee is flexed
Hyperextension

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A varus stress injury may rupture what?

LCL

(potentially also the PCL)

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In younger patients, what usually causes a meniscal tear?

High impact sports

Acute meniscal tears are often related to which other injury?

Acute ACL rupture

Large longitudinal tears in the meniscus may lead to what?

Large bucket handle tears with subsequent knee locking due to the meniscal fragment flipping into the intercondylar notch

Degenerate meniscal tears can occur ______________ or with a seemingly ____________ injury

Spontaneously Innocuous

Which type of meniscal tears tend to have complex patterns?

Degenerate (horizontal, longitudinal and radial components are common)

Degenerate meniscal tears are probably the first stage in the development of which condition?

Knee OA

Steinmann's test will be _________ for degenerate meniscal tears

Positive

Why should degenerate meniscla tears not be treated with arthroscopy?

Symptoms from such tears do not improve with resection

Why does the meniscus have limited healing potential and what causes healing potential to decline?

It only has an arterial blood supply to the outer 1/3rd Age and increased time from injury reduce the healing capacity

Which types of meniscal tears should be considered for repair?

Fresh longitudinal tears involving the outer 1/3rd of the meniscus in a younger patient

If a meniscal repair fails, what is required?

Arthroscopic menisectomy

What can aid the symptoms of a degenerate meniscal tear in the early period after injury?

Steroid injections

In acute meniscal tears which do not settle after 3 months, what is the treatment?

Arthroscopic partial menisectomy

Why are knees with degenerate changes on X-ray unlikely to benefit from arthroscopic menisectomy?

Removal of meniscal tissue is likely to increase stress on already worn and damged knee joint surfaces

What is the pricipal complaint of ACL deficiency?

Rotatory instability with giving way on turning

What is the rule of 1/3rds regarding outcomes for ACL injury?

1. 1/3rd compensate well and do what they like 2. 1/3rd manage by avoiding specific movements 3. 1/3rd do poorly with their knee giving way with normal movements

What are the treatment options for ACL injury?

1. Physio - strengthenign of quadriceps and hamstrings aids compensation 2. Patients who cope poorly in day to day activities or athletes may require ACL reconstruction

What does ACL reconstruction involve?

A tendon graft (patellar or semitendinosis and gracilis autograft) being passed through tibial and feoral tunnels at the usual location of the ACL in the knee and attachment to the bone (it may take up to a year to recover fully)

Which is more common, PCL rupture or ACL rupture?

ACL rupture is much more common

What is the treatment for an isolated PCL rupture?

**Conservative management** Only those with severe laxity and recurrent instability with frequent hyperextension or feeling unstable when descending stairs are considered for **reconstructive surgery**

What is used for PCL reconstruction surgery?

Cadaveric achilles tendon allograft

In terms of recovery, what is expected in the majority of MCL tears?

Healing with little or no instability will occur

How are acute MCL tears treated?

Hinged knee brace

What are the options for chronic MCL instability?

1. MCL tightening 2. Reconstruction with a tendon graft

What is the usual treatment of LCL tears?

Surgical with early repair or Late reconstruction with a tendon graft

With an LCL tear, patient will usually have what type of marked instability?

On rotational movement (excessive external rotation of the tibia, or varus stress)

What type of movement gives rise to an LCL rupture?

Hyperextension with varus impact

Due to the excessive stretch during a LCL tear, which nerve is commonly affcted or damaged?

Peroneal nerve | (common fibular nerve)

LCL ruptures are associated with multiple ligament knee injuries. Which artery is at risk during such injuries?

Popliteal artery

Why are regular checks on the circulation in the foot essential for patients with complete knee dislocations?

Intimal tears can occur in vessels which can later thrombose causing thrombosis

If thrombosis occurs in the lower limb subsequent to a complete knee dislocation, what risk does reperfusion pose?

Compartment syndrome | (fasciotomy may be required)

Acute injuries with large osteochondral fragments with large aspects of bone are fixed in what way?

Fixed with pins

Acute injuries with small osteochondral fragments, or fragments in a non-weight bearing area, with small aspects of bone are fixed in what way?

Arthroscopic removal

Describe the process of microfracture and why it is utilised

If defects have **bare bone** at their base microfracture can be used Involves **drilling small holes** into the bone base to induce bleeding This process causes **fibrocartilage** formation from stem cells which differentiate into chondroblasts

Under which circumstance may a patellar or quadriceps tendon rupture?

Rapid contractile force | (heavy lifing, fall, spontaneously)

What are some predisposing factors for an extensor mechanism rupture?

1. Tendonitis 2. Steroid use chronically (commonyl body-builders) 3. Diabetes 4. RA 5. Chronic renal failure 6. Use of quinolone antibiotics (e.g. ciprofloxacin)

Why should steroid injections be avoided in the treatment of tendonitis in the muscles of the extensor mechanism?

High risk of tendon rupture

What is the purpose of the straight leg raise test?

Determines if the extensor mechanism is intact

On X-ray what do the following suggest a) High-lying patella b) Low-lying patella

a) Patellar tendon rupture b) Quadriceps tendon rupture

What is the treatment for complete or substantial partial tears of extensor mechanism ruptures?

Surgical tendon to tendon repair or Surgical reattachment of the tendon to the patella

The pull of the quadriceps muscles tend to pull the patella in a slight _________ direction

Lateral

Patellofemoral dysfunction is commoner in which sex?

Females (wider hips and more lateral pull of patella)

Predisosing factors to patellofemoral dysfunction include?

1. Female gender 2. Joint hypermobility 3. Genu valgum 4. Femoral neck anteversion

Patients with patellofemoral dysfunction tend to complain of what?

1. Anterior knee pain (worse downhill) 2. Grinding or clicking at the front of the knee 3. Pseudolocking (after prolonged inactivity)

What are the treatment options for patellofemoral dysfunction?

1. Physio - especially strengthening the vastus medialis 2. Taping - to help alleviate symptoms 3. Surgery (a last resort)

The patella always dislocates \_\_\_\_\_\_\_\_\_\_

Laterally

When the patella dislocates, the ________ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ __________ tears and _____________ \_\_\_\_\_\_\_\_\_\_\_\_ may occur

When the patella dislocates, the **medial patellar ligament** tears and **osteochondral fracture** may occur (can be seen on X-ray as small opacification)

In a patellar dislocation, what may be seen on X-ray?

1. Small opacification (osteochondral fracture due to medial patellar facet striking the lateral femoral condyle) 2. **Lipo-haemarthrosis**

Predisposing factors patellar dislocation include?

1. Ligamentous laxity 2. Female gender 3. Shallow trochlear groove 4. Genu valgum 5. Femoral neck anteversion 6. Patella alta (high riding patella)

What are the treatment options for patellar instability?

1. Physiotherapy (to strengthen quads) 2. Tibial tubercle transfer or medial patellofemoral ligament reconstruction with tendon autograft

Knee Pathologies Flashcards

(74 cards)