Knee Flashcards by Hemanshu Monga

What are the risk factors for knee OA?

Genetic factors
Constitutional factors - increasing age, female gender, obesity and low bone density
Local factors - previous joint injury, occupational/recreational stresses on the joint, reduced surrounding muscle strength or joint laxity or malalignment

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What are the differential diagnosis for knee OA?

Meniscal or ligament injury
Referred pain from hip or back or ankle
Crystal arthropathies
Patella femoral arthritis

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What are the radiological features seen on x-ray of knee OA?

Loss of joint space
Osteophytes
Subchondral sclerosis
Sunchondral cysts

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What views can be requested of the knee in OA?

AP - weight bearing
Lateral - weight bearing
Skyline

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What classification can be used to classify the severity of knee OA?

Kellgren and Lawrence system - 5 grades from 0 to 4

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What are the conservative management options for knee OA?

Lifestyle modification - smoking cessation, weight loss, regular exercise
Adequate pain control - WHO analgesic pain ladder
Physio - slows disease progression
Steroid injections

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What are the two main surgical options for knee OA?

Total knee replacement - can last for at least 10 years but most 20 years and majority of pts have significant reduction in knee pain.

Partial knee replacement - localised disease for medial or lateral compartment and has faster recovery time

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What are the risk factors for patellofemoral OA?

Patella dysplasia

Previous patella fracture

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What are the clinical features of patellofemoral OA?

Anterior knee pain
Worse on activities that put pressure on patella e.g. climbing stairs

All other symptoms of OA may be present also

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What is the surgical management for patellofemoral OA?

Patellofemoral replacement but if other part of knee have OA the TKR may be required

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What is the function of the ACL?

Limits anterior translation of the tibia on the femur

Provides rotational stability

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What are the usual clinical features of ACL injury?

History of twisting the partially flexed knee whilst weight bearing, usually non contact

Unable to weight bear

Rapid joint swelling and significant pain - delayed presentation may describe leg ‘giving way’

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What are the tests that can be performed to assess ACL damage?

Lachman test
Anterior draw test
Pivot shift test

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What are the differential diagnosis of ACL injury?

Proximal tibia or distal femur fracture

Meniscal tear

Collateral ligament tear

Quadriceps tendon or patellar ligament tear

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What investigation should be initially ordered for suspected knee injury?

X-ray - AP + lateral

Rule out any bony injuries, any joint effusion or lipohaemarthosis

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What type of fracture may be seen in ACL injury?

Segond fracture - bony avulsion of the lateral proximal tibia

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What is the gold standard investigation for ACL injury?

MRI scan of the knee

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What is a commonly associated injury with ACL?

Medial Meniscal tear

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What is the immediate management of suspected ACL tear?

RICE

What is the conservative management for ACL rupture?

Rehab - muscle strength training of quadriceps - partially weight bear in cricket pad splint

What are the surgical options for ACL rupture?

Surgical reconstruction - using tendon or artificial graft - performed after period of prehabilitation where pt has undergone physio for a period of months

Acute surgical repair of ACL - depends on location of the tear - further assessed under GA knee arthroscopy and involves re-suturing the ends of torn ligament.

What is the main complication of ACL injury and reconstructive surgery?

Post-traumatic OA

What is the clinical features of PCL injury?

Less common

High energy trauma e.g. RTA Or low energy with hyper flexion of the knee with a planter-flexed foot

Immediate posterior knee pain + instability

What are the main complications of MCL injuries?

Instability of joint

Damage to saphenous nerve

What are the common causes of Meniscal tears?

Trauma-related injury - twisted of knee whilst flexed and weight bearing with onset of symptoms soon after Degenerative disease more common in elderly

What are the different types of Meniscal tears?

Vertical Longitudinal(bucket-handle) - most common Transverse(parrot-beak) Degenerative

What are the clinical features of Meniscal tears?

‘Tearing’ sensation Intense sudden-onset pain Swells slowly over period of 6-12 hours Free body in knee may lead to locked knee in flexion Tenderness, joint effusion and limited knee flexion

What test could be used to identify Meniscal tears?

McMurrays test | Apleys grind test

What are the investigations ordered for meniscus tears?

X-ray initially to exclude fracture MRI - Gold standard

What are the management options for Meniscal tears?

RICE Small tears just need RICE and will heal over few days Larger tears - arthroscopic surgery is indicated - tear in outer third (rich vascular supply) repaired using sutures - tear in inner third is usually trimmed to reduce symptoms - tear in middle can either be sutured or trimmed

What are the complications of Meniscal tears and surgery?

Secondary OA Knee arthroscopy - risk of DVT, damage to local structures e.g. saphenous nerve/vein, peroneal nerve and popliteal vessels

What are the clinical feature of a patella fracture?

Anterior knee pain History of trauma to the patella or strong contraction of quadriceps Pain worse on movement and unable to straight leg raise Significant swelling and bruising and a visible or palpable patellar defect

What are the differential diagnosis of patellar fracture?

Tibial plateau fracture Distal femur fracture Cruciate/collateral ligament injury Quadriceps tendon rupture

What is a congenital condition affecting the patella?

Bipartite patella

What the investigations ordered in a suspected patella fracture?

X-ray - AP + Lateral + skyline | CT - in comminuted fractures or in cases not overtly apparent on X-ray but clinically suggestive

What is AO foundation classification of patella fractures?

1. extra-articular or avulsion fractures 2. Partial articular fractures 3. Complete articular fractures

When is conservative management used in patella fractures and what is it?

Non-displaced or minimally displaced patella fractures or vertical fractures where extensor mechanisms remains Pts placed in brace or cylinder cast ensuring early weight bearing in extension before increasing flexion incrementally

When are surgical options used in patella fractures and what are they?

Significant displacement or compromise to extensor mechanism ORIF with tension band wiring Screw fixation can be used in simple transverse/vertical fractures Rare cases when ORIF not possible - partial/total patellectomy may be considered

What are the complication of patella fractures?

Loss of range of motion | Secondary OA

What are the risk factors for quadriceps tendon rupture?

Increasing age Male gender CKD, DM, RA Medications - corticosteroids and fluroquiniolones

What is the usual mechanism of injury for quadriceps tendon tear?

Sudden and excessive loading of quads such as landing from a jump

What are the differential diagnosis for quadriceps tendon rupture?

Patella tendon rupture Patella fracture Femoral shaft fracture

What investigations can be used in suspected quadriceps tendon rupture?

Usually clinical diagnosis especially in complete tear with palpable gap Can use x-ray to see fracture of caudal patella Ultrasound can be used to measure degree of rupture Sometimes MRI could be used

What are the management options for quadriceps tendon rupture?

Partial tears - immobilisation of the knee joint in a brace in tandem with intensive rehab Complete tendon tears - surgical intervention -tear at point of insertion with patella - repair using longitudinal drill holes or suture anchors -intra-tendinous tears - end-to-end sutures Post op knee immobilisation in a brace with progressive rehab introduced at 6 weeks post repair.

What are the three compartments of the knee?

Lateral Medial Patellofemoral