Knee Injury Flashcards
1
Q
Six common knee injury?
A
- Fracture of femoral condyle
- Fracture of tibial plateau
- Patellar fracture
- Ligament injury
(ACL, PCL, MCL, LCL) - Meniscal injury
(MM, LM) - Miscellaneous
- patellar dislocation
- knee dislocation
2
Q
6 mechanism of knee injury and its DDX?
A
- Fall on knee
- patellar fracture
- tibial plateau fracture
- femoral condyle fracture - Valgus force
- MCL tear
- medial condyle fracture - Varus force
- LCL tear
- lateral condyle fracture - Rotational force on flex knee
- ACL
- MM, LM
- MCL, LCL - Anterior tibial force on flex knee
- PCL - Hyperextension
- supracondylar fracture
3
Q
Relevant knee anatomy?
A
- 2 joint
- tibiofemoral (hinge joint)
- patellofemoral - 4 ligaments
- ACL, PCL, MCL, LCL - 4 Extensor apparatus
- prox to distal (quads, quad tendo, patella, patellar tendon)
4
Q
Types of femoral condyle fracture and its mechanism?
A
- Direct
i. supracondylar
ii. intercondylar (T/Y)
iii. unicondylar - Indirect
i. varus - lateral condyle
ii. valgus - medial condyle
iii. hypertension - supracondylar
5
Q
Treatment for femur condylar fracture?
A
- Unicondyle
- non-displaced: cast 3-6 weeks
- displaced: ORIF with cancellous screws +/- buttress plate - Intercondyle
- ORIF with blade plate, dynamic condylar screw (DCS), locking compression plate (LCP) - Supracondylar
- ORIF with nail or plate
6
Q
Complication of femur condylar fracture?
A
- Knee stiffness
- intraarticular or periarticular adhesion - Osteoarthritis
- highly associated with interarticular fracture - Malunion
- varus
- valgus - Disused atrophy
- extensor weakness
7
Q
Types of patellar fracture?
A
- displaced/non-displaced
- displaced: due to strong quadriceps contraction
- non-displaced: held by pre-patellar expansion of quad tendon in front, and patellar retinaculae on its sides - two-part fracture
- transverse fracture due to quad pull - comminuted/stellate fracture
- high energy, usually a blow on patellar on flexed knee
8
Q
Treatment for patellar fracture?
A
- Undisplaced: Cylinder cast from groin to above malleoli fr 3 weeks and physio
- Two-part fracture:
- Tension-band wiring (TBW) and repair of extensor retinaculae
- +/- patellectomy if difficult to achoeve accurate reduction - Comminuted: Patellectomy
9
Q
Ligament injury and its mechanism?
A
- Valgus force: MCL tear, usually at femoral attachment
- Varus force: LCL tear usually with avulsion of head of fibula. Uncommon compare to MCL.
- Twisting force on semi-flexed knee: ACL. O’Donoghue triads: ACL + MCL + MM. (Can be associated with MM or LM tear)
- Anterior tibial force on semi-flexed knee: PCL
10
Q
Classification of ligament injury?
A
- First degree - few fibres only. CF: minimal swelling, localised tenderness, little functional loss. Pain with stress test.
- Second degree - more than 1/3 tear. CF: Pain, swelling, cannot use the limb due to pain. Bt joint movement preserved. Pain with stress test.
- Third degree - complete tear. CF: Swelling, pain may be minimal. Joint open-up wih stress test.
11
Q
Treatment for ligament injury?
A
1. Conservative (First and second degree) i. aspirate haematoma ii. immobilise with cast iii. physiotherapy
- Operative
(Third degree)
i. if come early within 2-3 weeks: ligament repair (+fascial or tendon graft):
ii. late presentation with knee instability: ligament reconstruction (use tendon or fascia lata)
12
Q
Types of tibial plateau fracture and its mechanism?
A
Mechanism of injury:
- direct: land on knee
- indirect: valgus or varus force on knee
Types of fracture? (Scatzker Classification) I - Lateral split fracture (+- LM) II - Lateral split-depressed fracture III - Lateral pure depression fracture IV - Medial plateau fracture (+- MM) V - Bicondylar fracture (+- ACL) VI - Metaphyseal-diapheseal dissociation (+- ACL)
13
Q
Anatomy of tibial plateau?
A
- Bone
- lateral plateau (convex, more proximal)
- medial plateau (concave, more distal) - Muscle
- anterior comprtment muscles (attach to anterolateral tibia)
- pes anserine (attach to anteromedisl tibia) - Biomechanics
- medial plateau bears 60% of knee load
14
Q
Treatment of tibial plateau fracture?
A
- Non-operative: Minimally displaced or depressed, non ambulatory pt
- hinged knee brace
- PWB for 8 weeks
- immediatel passive ROM - Operative:
i. Temporary bridging Ex-Fix, with delayed ORIF or
ii. Ex-fix with limited In-Fix - Post-Op:
- same as non-operative
15
Q
Medial vs lateral menisci?
A
Medial meniscus
- c-shaped
- cover 50% of medial tibial plateau
- more common site of injury (non-flexible, attached to MCL and tibia via coronary ligament)
Lateral meniscus
- circular shape
- cover 70% of lateral tibial plateau
- more flexible than MM
