13 - T&O Knee and Leg Flashcards by Armit Singh

What are some risk factors for knee OA?

Knee is the most commonly affected joint by OA!

Female
Obese
Previous injury
Ligament laxity

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How does knee OA present and what are some differentias for this?

Pain in the knee that can radiate to hip and thigh
Exacerbated by exercise and relieved by rest
Joint stiffness
Reduce range of movement
Crepitus

Differentials: meniscal or ligament injury, crystal arthropathies, patellofemoral arthritis

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What are some investigations you should do when you suspect knee OA?

- Plain film radiograph AP and lateral

Skyline view for patella involvement
If suspect other diagnosis e.g ligaement injury then MRI

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How is knee OA classified?

Kellgren and Lawrence system

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How is knee OA managed?

Conservative

weight loss, smoking cessation, regular exercise, NSAIDs, physiotherapy to slow disease progression

Surgical

total knee replacement (lasts 10 years)
partial unicondylar knee replacement if disease localised to medial or lateral condyle. has faster recovery but may need full replacement at one stage

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What is patellofemoral arthritis and how is it managed?

OA affecting articular cartilage along the trochlear groove and the underside of the patella. May occur with patella dysplasia or previous patella fracture

Symptoms: anterior knee pain worse when pressure on patella (e.g climbing stairs), joint stiffness, swelling

Dx: skyline plan film radiograph

Mx: conservative then patellofemoral replacement. (if OA in other parts of knee will need TKR)

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How does an ACL tear present?

History of twisting the knee whilst weight bearing (non contact change of direction on flexed knee)
Unable to weight bear
Rapid joint swelling (haemarthrosis due to ligament being vascular)
Pain
Instability if delayed presentation

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What special tests can diagnose an ACL tear?

- Lachmans test: put knee in 30 degrees flexion then one hand stabilises the femur and the other pulls the tibia foward, check both knees for comparison

- Anterior drawer test: flex knee to 90 degrees, place thumbs on joint line and index fingers on hamstring tendons posteriorly, force then applies

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What investigations should you do if you suspect an ACL tear and what are some differentials?

- Plain film radiograph AP and lateral: exclude bony injuries, joint effusion, lipohaemarthrosis. (Segond Fracture usually means ACL tear)

- MRI of knee: gold standard, can pick up any associated meniscal tears (usually medial)

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What is a Segond fracture?

Bony avulsion of the lateral proximal tibia that is most likely caused by an ACL tear

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How is ACL managed?

Immediate RICE

Conservative (less active patients)

Patient can often weight bear so cricket pad knee splint for comfort and send home

- Rehabilitation to strengthen quadriceps that stabilise the knee

Surgical (more active)

Arthroscopic reconstruction with tendon or artifical graft. Often done after some time and prehabilitation. Doesn’t reduce risk of OA
Sometimes acute repair can be done if MRI favourable, do GA and arthroscopy and resuture ends of torn ligament

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What is the complication of ACL tears and ACL reconstruction surgeries?

Post-traumatic OA

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What is the function of the MCL and how can injuries to the MCL be classified?

Most commonly injured ligament of knee. Acts as valgus stabiliser of knee so when forces are applied to lateral knee it tears

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How does an MCL tear present and what are some differentials?

History of trauma to lateral knee or valgus stress with external rotation (skiing)
May hear pop then immediate medial joint line pain
Swelling a few hours later
Tender along joint line
Can still weight bear

Differentials: fractures, menismcal injury, multi-ligament tears

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What special tests can aid your diagnosis of a MCL injury?

Valgus stress test

Will have increased laxity and reproduction on painwhen testing MCL

Do flat and then in 20/30 degress flexion

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How is a suspected MCL tear investigated?

Plain film radiograph AP and Lateral to exclude dracture
Gold standard MRI

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How are MCL tears managed and what are some complications that can arise with an MCL tear?

Grade I: RICE with NSAIDs. Strength training and return to full exercise within 6 weeks

Grade II: Analgesia with knee brace. Weight bearing/strength training and return to exercise within 10 weeks

Grade III: Analgesia with knee brace and crutches. If distal avulsion surgery. Return to exercise within 12 weeks

Complications: instability in joint, damage to saphenous nerve

What is the role of the medial meniscus and the pathophysiology of injury to this structure?

Shock absorber of the knee joint and increases the articulating area. It is connected to the MCL

- Trauma related injury (young person twisted knee whilst weight bearing)

- Degenerative disease

How does a meniscal tear present and what will you find on examination ?

Symptoms

Tearing sensation
Intense sudden onset pain
Slow swelling over 6-12 hours
If bucket handle may be locked in flexion

Examination

Joint line tenderness
Joint effusion
Limited knee flexion
Mcmurray test (may be too painful)

How are meniscal tears investigated and managed?

Plain film radiograph to exclude fractures
Gold standard: MRI

RICE if <1cm
Arthroscopic surgery if large and symptomatic

What are some complications of meniscal tears and arthroscopy to treat them?

Meniscal Tear: OA

Arthroscopy: DVT, damage to saphenous nerve/vein, damage to peroneal nerve, damage to popliteal vessels

How do patella fractures present?

Often in 20-50 year old males due to either direct trauma or rapid eccentric contraction of quadriceps

Anterior knee pain following trauma (e.g dashboard injury)
Pain worse on movement
Cannot straight leg raise
Swollen and bruised
Palpable patella defect

What else can cause a palpable defect in the patella apart from a fracture?

Bipartite patella

What are the investigations and management for patella fractures

Plain film radiographs three views (AP, Lateral, Skyline)
CT if comminuted

Conservative: if non/minimally displaced then put in brace or cylinder cast with early weight bearing in extension

Surgical: if displacement or damage to extensor mechanism then open reduction and internal fixation (ORIF) with tension band wiring. If simple vertical/transverse fracture can screw fix not wiring

What are some complications of a patella fracture?

- Loss of range of motion - Secondary patellofemoral OA

What is the pathophysiology of a tibial shaft fracture and what are some complications of this?

- Direct (fall) or indirect injuries (twisting/bending) due to lack of significant soft tissue envelope (especially anteromedial) - Higher risk of open fractures and compartment syndrome **- Complications:** compartment syndrome, open fractures, malunion (if treated non-operatively), non-union

How does a tibial shaft fracture present?

- History of trauma - Severe pain and inability to weight bear - Clear deformity, significant swelling/bruising - Assess for open fracture and compartment syndrome (excessive pain out of proportion and on passive stretch) - Assess neurovascular status

How do you investigate someone with a suspected tibial fracture?

**- ATLS:** urgent bloods, G+S, coagulation **Full length AP and Lateral plain film radiographs** from knee to ankle **- CT imaging** if potential intraarticular extension or spiral fracture suspected

How is a tibial shaft fracture managed?

**_Initially_** - ***Reduce in A+E*** with analgesia/sedation to correct length and rotation and put in above knee backslab - ***Elevate immediately*** and closely ***monitor for compartment syndrome*** - ***Post manipulation plain radiographs*** and ***neurovascular status reassessed*** **_Definitive_** - Non operative if closed and stable then ***Sarmiento cast*** - Surgical: * ***Intramedullary nailing*** so can fully weight bear after * If proximal/distal fracture extending intraarticular then ***ORIF with locking plates*** * If multiple injuries may need ***temporary external fixation*** until surgery

What fractures are associated with tibial shaft fractures?

**Fibula** Low energy: fracture at different level High energy: fracture at same level Can often be left alone as heal well after tibial treatment

What is the pathophysiology of tibila plateau fractures and what are some complications of this fracture?

Often due to **high energy trauma and impaction of the femoral condyle** on the tibial plateau (e.g fall from height, RTA) **Lateral tibial fracture more commonly** fracturedas varus deforming force. **Associated ligament and meniscal injuries** **Complications:** post-traumatic arthritis almost definite

How will a tibial plateau fracture present?

- History of trauma (usually axial loading) - Sudden onset pain and unable to weight bear - Swelling of knee due to lipohaemarthrosis - Tenderness of medial/lateral tibia - May have ligament instability - Check peripheral neruovascular status

What are some differentials you should consider with knee pain after knee trauma?

- Patella dislocation - Patella or distal femur fracture - Meniscal injuries - Ligament injuries - Patella/quadriceps tendon rupture - Tibial fractures

How are tibial plateau fractures investigated and classified?

**- AP and Lateral plain film radiograph** which will show lipohaemarthrosis **- CT scanning** to assess severity and intra-op plan **- Schatzker Classification**

How are tibial plateau fractures managed?

**- Open reduction and internal fixation (ORIF)** to restore joint surface congruence. Any metaphyseal gaps can be filled with bone graft **- Post operative hinged-knee brace** with non-weight bearing for 8-12 weeks **- May need external fixation** and delayed ORIF if poly trauma or significant soft tissue injury

What are the risk factors for IT band syndrome and how does it present?

- **Shared aponeurosis of gluteus medius and tensor fascia lata** gets inflammed **- Lateral knee pain exacerbated by knee exercise** (often in athletes or people with sudden increase in exercise) - Exam often remarkable but can do Nobles and Renne test - Risk factors: repetitive flexion/extension (runners, weight lifters, cyclists), foot pronation, genu varum, hip abductor weakness

How is IT band syndrome investigated and managed?

**_Diagnosis_** Clinical but can use MRI/Xray to exclude other pathology **_Management_** - Modify activity and use analgesics in acute pain - Local steroids - Physiotherapy - If symptomatic or functionally limited after 6 months despite other treatment surgical release of IT band from patella

What is contained within the popliteal fossa?

Popliteal artery is continuation of femoral artery

What is a knee dislocation and why is it a serious injury?

- When 3 of the 4 ligaments of the knee are disrupted - Limb threatening as can damage **popliteal artery** causing compartment syndrome - Can also damage **common peroneal nerve** - Need to reduce and put in knee brace, may need surgery to reconstruct ligaments

Why are patella fractures often displaced?

Due to pull of quadriceps tendon, often need fixation

What are the complications of a total knee replacement?

Can do osteotomy instead of TKR in younger patients

What is the significance of central meniscal tears?

This area is avascular so less likely to repair