Knee Problems Flashcards
What type of injury causes a meniscal tear?
Classically a twisting force on a loaded knee
e.g. turning in football, squatting
Degenerative tears occur with low energy injuries
How does a meniscal tear present?
Localised pain to medial (most common) or lateral joint line
Effusion develops the following day
Catching or locking sensation
Which examination findings would be seen in a meniscal tear?
Effusion
Joint line tenderness
Steinman’s test –> pain on tibial rotation localising to the affected compartment
Which type of meniscal tear causes locking of the knee and what would be seen on examination?
Bucket handle from longitudinal tear
–> 15 degree block to full extension
How is a meniscal tear diagnosed?
MRI
What is the initial management of any soft tissue knee injury?
RICE –> Rest, Ice, Compression, Elevate
Which meniscal tears can be repaired with surgery and why?
Generally only repaired if fresh, longitudinal tear in outer 1/3 of meniscus in a young patient
–> menisci have limited blood supply so very poor healing potential
What is the general management of meniscal tears?
Conservative, usually settles with time
(90% not suitable for surgery)
If no better after 3 months, can consider partial meniscectomy
Which type of injury can cause an ACL rupture?
High rotational force, turning upper body laterally on a planted foot e.g. football, rugby, skiing
How does an ACL rupture usually present?
Pop usually felt or heard
Haemarthrosis within an hour of injury
Deep pain in knee
Rotational instability –> gives way when turning on a planted foot
What would be seen on examination in an ACL rupture?
Swelling
Excessive anterior translation on anterior drawer test + Lachman’s test
What is the gold standard for diagnosis of an ACL rupture?
MRI
–> also detects meniscal tears (50% of ACL ruptures also have a meniscal tear
What are the management options for ACL rupture?
Conservative –> rehab/physio
Surgery –> ACL reconstruction (only if professional sportsperson or giving way on sedentary activity)
What is the prognosis for ACL ruptures managed conservatively?
1/3 compensative very well
1/3 manage with avoiding certain activities
1/3 do poorly
What is the most common ligamentous knee injury?
MCL tear
What type of injury causes an MCL tear?
Valgus stress injury e.g. rugby tackle from the side
What are the clinical features of an MCL tear?
Laxity + pain on valgus stress with tenderness over origin + insertion of MCL
What is the management for MCL tears?
Conservative –> forgiving ligament, most heal by themselves
If chronic instability –> MCL tightening or reconstruction
What kind of injuries cause a PCL rupture?
Direct blow to anterior tibia with knee flexed e.g. motorcycle crash
Or hyperextension of knee
(usually multiple ligament injuries, rarely occurs in isolation)
Which other structures will be injured in a complete knee dislocation?
Rupture of all four ligaments
High incidence of neuromuscular injury
How is a complete knee dislocation managed?
Should be reduced as an emergency +/- temporary external fixation
Regular checks on vascular status below knee (thrombosis may occur) –> vascular stenting/bypass
Reperfusion may cause compartment syndrome –> fasciotomies
Usually multiple ligament reconstruction required
Which structures make up the extensor mechanism of the knee?
Tibial tuberosity Patellar tendon Patella Quadriceps tendon Quadriceps
What type of injury causes an extensor mechanism rupture and in which group of patients?
Rapid contractile force e.g. lifting or spontaneous if degenerative
Patellar tendon <40s
Quadriceps tendon >40s
What are some risk factors for extensor mechanism rupture?
Tendonitis Chronic steroids e.g. body builders DM RA CKD Quinolones e.g. ciprofloxacin can cause tendonitis --> rupture
What would be found on examination in an extensor mechanism rupture?
Obvious palpable gap
Straight leg raise test +ve
What might be seen on xray in an extensor mechanism rupture?
High or low lying patella (depending on which tendon)
How is an extensor mechanism rupture diagnose?
Clinical +/- USS confirmation
How is an extensor mechanism rupture managed?
Surgical repair –> tendon to tendon repair or reattached of tendon to patella
What is patellofemoral dysfunction?
Anterior knee pain due to disorder of patellofemoral articulation
What are the clinical features of patellofemoral dysfunction?
Anterior knee pain, worse going downhill
Grinding/clicking sensation
Stiffness after sitting –> pseudo locking (acutely stiffens in flexed position)
Which type of injuries cause patellar dislocation?
Direct blow or sudden twist of knee
Which way does the patella usually dislocate?
Laterally
Which other structures might be injured in a patellar dislocation?
Tear of medial patellofemoral ligament
Osteochondral fracture when medial patella strikes the lateral femoral condyle (small opacification on xray)
Lipohaemarthrosis may occur (characteristic fat pad on xray)
