Clinical reasoning for acute lower limb injury

How to select examination techniques to confirm/ negate hypothesis ? 

Examination technique	What to look for
Observation	Location  Severity ( how much )  Of swelling + bruising   → swelling + bruising accumulate at lower parts due to gravity → location of bruising + swelling doesn’t mean it is the location of injury
Assessment of articular effusion	If swelling can be moved around to see if it is in the joint  → Yes: Intra-articular ligament injured
Palpation	Along the length of ligament + move from one ligament to other  *palpate carefully + systematically
Ligament stress test	A test that takes ligament through stress  + compared to other side ( uninjured )  Different grades of injury → severity of injury
Other tests	Function → how it relates to the injury  ROM  Muscle strength/ endurance → any compromise to muscles’ ability to protect joint   Muscle control → is muscle control around injury normal  Balance/ proprioception → static/ balance → balance is commonly affected after ankle injuries

Grades of ligament injury

	ROM/ laxity	End feel	Pain
Grade 1 ( some fibres torn )	X increase in laxity	FIrm	Reproduction of pain
Grade 2 ( considerable no. of fibres torn )	↑	Firm
Grade 3 ( complete tear )	↑	Not firm	may/ may not reproduce pain

What are the impacts of acute ankle/ knee injuries ? 

Impacts	Symptoms
Chronic ankle instability	Repeated ankle sprain  Episodes of giving away  Feeling of instability  Impairments in balance/ dorsiflexion ROM/ muscle strength
Impingement	Pain at end of motion
ACL injury	Copers:  No giving away  Able to participate to pre-injury activity / level 1-2 sports  Non-copers:  Knee instability  Can’t participate in pre-injury activities  No difference in laxity  Acute to chronic:  Increased rate of osteoarthritis  Patellofemoral pain  Persistent instability + X return to sports

What are the key elements of a physical exam suggesting a fracture ? 

Key elements	What to look for
Observation	Amount of swelling + where swelling is  → expected: significant  → swelling + bruising accumulate at lower parts due to gravity → location of bruising + swelling doesn’t mean it is the location of injury
Palpation	Palpate carefully + systematically  → pain ?  → slowly increase depth of fracture
Loading/ weight-bearing
Vibration	Suspect fracture at bone → move approximally + distally to tap on bone → if fracture → vibrations travels down bone + cause irritation at fracture
Compression/ bending	Move away from the fracture site → cause bending at fracture to reproduce pain

Ottawa knee rules

Ottawa ankle rules → for suspected fractures  to refer for X-ray 

1. Bony tenderness at posterior edge of lateral + medial malleolus + base at 5th metatarsal + navicular 

2. Inability to weight bear immediately + in ER when loading bone in question ( fracture in 5th MT but would still be able to weight bear on medial side of foot ) 

→ pick right ppl to X-ray 

Ottawa knee rules 

1. Tenderness at head of fibula 

2. Isolated tenderness of patella 

3. Inability to flex knee 90’ 

4. Inability to bear weight ( X take 4 steps ) immediately + at presentation

What are common sites + anatomical considerations of meniscus injuries 

Anatomical considerations : 

Medial meniscus: attaches to capsule + MCL 

1. FIrm tibial attachment 

2. Less mobile than lateral meniscus 

Lateral meniscus: no attachment to LCL / capsule

1. Less firm tibial attachment 

2. More mobile 

3. Less commonly injured in acute mechanisms 

MOI what to ask 

1. Weight bearing foot 

2. Twisting mechanism 

3. Range of initial pain 0 - extreme 

4. Swelling + symptoms progress over 24 hrs 

5. Locking + catching 

Key elements of physical exam: 

1. Checking for locking/ catching 

2. Assessment of articular effusion 

3. Joint line palpation 

4. Non-weight bearing compression/ rotation tests 

5. Weight bearing compression/ rotation tests

Dislocation risk factors + physical exam key elements

Dislocation risk factors: 

1. Knee hyper E 

2. Genu valgum 

3. Patella alta 

4. Patellar tilt 

5. Generalised hypermobility 

Physical exam key points if patellar dislocation : 

1. Apprehension 

2. Effusion 

3. Pain on palpation 

4. Pain on quadriceps contraction 

Beighton scale: 

Assesses general joint hypermobility → out of 9 points / > 5 is hyper mobile 

Common muscle injuries + MOI + key elements of physical exam

What are common muscles injured ? 

1. Hamstrings 

2. Quadriceps 

3. Gastrocnemius 

MOI what to ask : 

1. Limb position 

2. Contraction/ stretch 

3. Extrinsic force 

4. Amount of pain/ swelling 

5. Speed of swelling onset 

6. Immediate weight bearing function 

7. Progress since 

Key elements of physical exam: 

1. Observation 

2. AROM 

3. Progressive resisted contraction 

4. PROM/ muscle lengthening

5. Palpation

Factors affecting risk of re-injury + potential impairments

Factors increasing risk of re-injury: 

1. Muscle strength 

2. Agonist: Antagonist strength ratio 

3. Fascicle length

Potential impairments: 

1. Function

2. Muscle inhibition/ contraction 

3. Muscle length 

4. Muscle strength/ endurance/ power 

5. Muscle control