Orthopaedic Knee Conditions Flashcards by Robbie Pollock

what is the bone anatomy of the knee?

Femur - Distal end shaped into condyles
Tibia - Tibial plateau, Shaped to fit condyles and movement
Patella - Sesamoid bone

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what are the key. muscles of the knee?

Extensors - Quadriceps - Quadriceps made of 4 muscles – vastus lateralis, vastus medialis, rectus femoris and vastus intermedialis. Oblique fibres at the most distal parts are important in the control on the knee cap
Flexors - Hamstrings

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what are the ligaments of the knee?

Cruciate ligaments - Acl and pcl
Collateral ligaments - Mcl and Lcl

Medial collateral ligament is attached to the meniscus but on the lateral side it is not

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whata re the meniscii of the knee?

Specialised c-shaped cartilages
Triangular in cross-section
Medial - Attached to Deep mcl
lateral

Thin on medial side and thicker more lateral

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what is the function of the meniscii?

Aid force transmission
Increase stability

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what are the different way meniscal tears can be caused?

Acute - Twisting esp in deep flexion
Degenerative - osteoarthritis

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what meniscal tears are more common?

•Medial meniscal tears more common - More fixed structure

Different kinds of meniscal tears. Degenerative tears are most often seen posteriorly. Medial menisci tears are more common that lateral ones due to the medial menisci being more fixed

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what is the presentation of a meniscal tear?

Pain
Clicking
Locking
Intermittent swelling

Menisci tears often in younger people, about 40s, over 60 it is often degenerative cause

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what is done and found on examination of a meniscal tear?

Look - effusion
Feel - Tender joint line at point of tear (esp medial tear)
Move:
Mechanical block to movement
McMurrays test positive
Fail deep squat - In someone with an acute meniscal tear then cant squad down and walking that position (duck waddling)
Thassaly’s test positive - Thassaly’s test is when they stand on one leg and rotate outwards and there is pain then it is a lateral meniscal tear but if they rotate inwards and there is pain then it is a media meniscal tear

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what investigaitons may be sued for a meniscal tear? (Investigations not always necessary)

•X-ray:

Arthritis
Fracture

•MRI:

Most sensitive test
High False positive rate

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a meniscal tear is unlikely to heal due to poor blood supply, what are some non-operative managements?

Rest
Nsaids
Physiotherapy - Hamstring and Quadriceps strengthening

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what si the operative treatment of a meniscal tear?

Arthroscopy:

Repair
resection

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what is osteoarhtritis?

Degenerative change of synovial joints
Progressive loss of articular cartilage
Secondary bony changes

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how doe sosteoarhtritis present?

Characterised by worsening pain and stiffness of the affected joint
Limiting everyday life

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what is the conservative management of osteoarthritis?

Weight loss -Highly associated with increased weight and if this is decreased these decreases weight going through knee when going up stairs
Analgesia
Activity Modification
Braces
Walking aids
Visco-supplementation
Steroid Injections

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what is the opeerative management of osteoarthritis?

Most arthritic knee get a TKR

2 types of TKR – in cruciate retaining the anterior cruciate is sacrificed and the posterior cruciate is kept

Medial uni-compartmental is the most common out of them, resurfacing medial part of the femur and tibia and plastic bearing in-between

Lateral uni-compartmental knee replacement are much less common

About 90% of arthritis knees need total knee replacement

what is the ACL and its features?

32mm length x 7-12mm width
Runs from between tibial eminences to lateral wall of intercondylar notch of femur
Blood Supply: middle geniculate artery
Innervation: posterior articular nerve
Branch of tibial nerve

what is the function of the ACL?

Primary restraint to anterior translation of the tibia relative to femur
Secondary restraint to tibial rotation and varus/valgus stress

how is the ACL injured and in who?

Non-contact pivot injury
Females : males = 4.5:1
Landing biomechanics neuromuscular activation patterns
quadriceps

what is the presentation of a ACL tear?

Heard a ‘pop’ or ‘crack’
Immediate swelling (70%) - haemarthrosis (haemorrhage into a joint space and can be regarded as a subtype of a joint effusion)
Unable to continue playing - Can walk in straight line ()As soon as they twist or turn the knee becomes instable
Deep pain

what would be looked for and foun don examination of a ACL tear?

Look - Effusion (if recent injury), may involve blood
Feel
Move:
Anterior draw
Lachmann’s test
Pivot shift - Best done under anaesthetic

what investigaitons would be done for a ACL tear?

X-ray:

•Segond fracture - Avulsion # of anterolateral ligament

MRI:

ACL
Meniscii
Lateral – simultaneous with acl tear (48%)
Medial – secondary to shear from chronic instability

•MCL

what is the treatment of a ACL tear?

Non-operative - Focussed quadricep programme

Operative - ACL reconstruction:

+/- partial menisectomy +/- ligament repair or augmentation
Hamstring graft

ACL repair doesn’t really work, need tissue from elsewhere so often hamstring

what is the anatomy of the MCL?

* Superficial and deep mcl * Superficial = primary restraint to valgus stress * Deep = contributes in full knee extension, attaches to medial meniscus, continuous with joint capsule

what is the most common ligament injury of the knee?

MCL tear

how do MCL tears occur?

* Severe valgus stress * Usually contact-related * Associated injuries: - ACL tear - Meniscal tear

what is the presentation of a MCL tear?

* Heard a ‘pop’ or ‘crack’ * Pain ++ - Medial side * Unable to continue playing * Bruising medial knee * Localised swelling

what would be seen on examination of a MCL tear?

Look: * Medial swelling * bruising Feel: * Tender medial joint line * Tender femoral insertion of mcl Move: * Painful in full extension * Opening on valgus stress

what imaging is done for a MCL tear?

X-ray: * May be normal * Calcification at femoral insertion (Pellegrini-stieda) - Chronic injury Get x-ray to exclude any other bony injury MRI: * Modality of choice * Assess location and severity of injury * Identify other pathologies

what is the non-operative treatment of a MCL tear?

* Majority * Rest, NSAIDs * Physiotherapy * Brace for comfort

what is the operative treatment of a MCL tear?

* Severe tears * Failed non-operative management * Repair or reconstruction * Repair: avulsions, midsubstance tear with good tissue * Reconstruction: damaged tissue

what is Osteochondritis dissecans?

Osteochondritis dissecans (OCD) is a condition that develops in joints, most often in children and adolescents. It occurs when a small segment of bone begins to separate from its surrounding region due to a lack of blood supply * Pathological lesion affecting articular cartilage and subchondral bone * 2 forms: * Juvenile - 10-15 years while growth plates still open * Adult Osteochondral fractures are a separate thing, osteochondritis is an area of detached bone due to limited blood supply and is not normally related to trauma

what is the cause of Osteochondritis dissecans?

* Hereditary * Traumatic * Vascular - Adult form - Interruption of vascular supply Not too sure on cause

what is the most common place for osteochondritis dissecans to occur?

* Knee = most common * Posterolateral aspect of medial femoral condyle (70%)

what is the presentation of Osteochondritis dissecans?

* Activity-related Pain - Poorly localised * Recurrent effusions * Mechanical symptoms: - Locking - block to full movement one of the ocmmonest causes of osteochondral fractures If fragment becomes lose you get locking symptoms and if it falls into the knee it can cause a lose body and the patient presents with a blocked full extension

what would be seen and done on examination of Osteochondritis dissecans? (History often gives story)

* May be normal * Look - effusion * Feel - Localised tenderness * Move: - stiffness - Block to movement - Wilson’s test - flex knee over the end of the bed and then internally rotate the knee as you extend the joint and if it is painful on internal rotation and compression it suggests there may be a an area of osteochondritis

what investigaitons owuld be done for Osteochondritis dissecans?

X-ray - Add in tunnel view (flexed 30-50 deg) (Don’t always seen in normal view so get tunnel view) MRI: * Lesion size * Status of cartilage and subchondral bone * Signal intensity - Oedema suggests instability of fragment

what is the treamtent of Osteochondritis dissecans?

Non-operative: * Restricted weight-bearing * ROM brace Operative: * Arthroscopy - Subchondral drilling, Fixation of loose fragment * Open fixation