Knee Flashcards
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
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
What are the radiological features seen on x-ray of knee OA?
Loss of joint space
Osteophytes
Subchondral sclerosis
Sunchondral cysts
What views can be requested of the knee in OA?
AP - weight bearing
Lateral - weight bearing
Skyline
What classification can be used to classify the severity of knee OA?
Kellgren and Lawrence system - 5 grades from 0 to 4
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
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
What are the risk factors for patellofemoral OA?
Patella dysplasia
Previous patella fracture
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
What is the surgical management for patellofemoral OA?
Patellofemoral replacement but if other part of knee have OA the TKR may be required
What is the function of the ACL?
Limits anterior translation of the tibia on the femur
Provides rotational stability
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’
What are the tests that can be performed to assess ACL damage?
Lachman test
Anterior draw test
Pivot shift test
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
What investigation should be initially ordered for suspected knee injury?
X-ray - AP + lateral
Rule out any bony injuries, any joint effusion or lipohaemarthosis
What type of fracture may be seen in ACL injury?
Segond fracture - bony avulsion of the lateral proximal tibia
What is the gold standard investigation for ACL injury?
MRI scan of the knee
What is a commonly associated injury with ACL?
Medial Meniscal tear
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?
- extra-articular or avulsion fractures
- Partial articular fractures
- 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
