13 - T&O Knee and Leg Flashcards
What are some risk factors for knee OA?
Knee is the most commonly affected joint by OA!
- Female
- Obese
- Previous injury
- Ligament laxity
How does knee OA present and what are some differentials 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
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
How is knee OA classified?
Kellgren and Lawrence system
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
What is patellofemoral arthritis and how does it present? How is it diagnosed and 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)
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
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
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)
What is a Segond fracture?
Bony avulsion of the lateral proximal tibia that is most likely caused by an ACL tear
How are ACL tears 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
What is the complication of ACL tears and ACL reconstruction surgeries?
Post-traumatic OA
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
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, meniscal injury, multi-ligament tears
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
How is a suspected MCL tear investigated?
- Plain film radiograph AP and Lateral to exclude fracture
- Gold standard MRI
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?
Ix
- Plain film radiograph to exclude fractures
- Gold standard: MRI
Mx
- RICE if <1cm
- Arthroscopic surgery if large and symptomatic
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
Ix
- Plain film radiographs three views (AP, Lateral, Skyline)
- CT if comminuted
Mx
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 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, how should you assess this?
- 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
Mostly surgical management, Urgent Operation occurs due to compartment syndrome, an ischaemic limb or an open fracture
Definitive
- Non operative if closed and stable then Sarmiento cast
- Surgical:
- Intramedullary nailing so can fully weight bear after
- If proximal/distal fracture extending into the joints then ORIF with locking plates
- If multiple injuries may need temporary external fixation until surgery
What is the pathophysiology of tibial 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 fractured as 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
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
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
