Pathology in the Hip, Knee and Foot Flashcards
Where does pain in the hip present? Where might it radiate to and why?
Presents with pain in the groin
This may radiate to the knee as the obturator nerve supplies both areas
May also present in buttock
What range of motion is usually first to be lost in hip pathology?
Internal rotation
Conditions that may require total hip replacement/hip arthroplasty
Primary OA
RA
Seronegative inflammatory arthropathies
Perthes
AVN
Dysplasia
SUFE
What is the Gold Standard form of hip replacement?
Cemented metal head/polyethylene cup
How long can a replacement hip be expected to last?
What may rarely happen to a replacement hip?
In low demand patients, replacements should last 15-20 years
In less than 5% of patients, loosening of the implant may develop, predominantly due to particles from the metal bearing being released and causing an inflammatory response
Macrophages ingest the particles, release inflammatory cytokines and recruit osteoclasts
What conditon is classically characterised by a “hanging rope” sign on Xray?
late sign of Avascular Necrosis - patchy sclerosis in the weight bearing area of the femoral head, lytic zone underneath formed by granulation tissue from attempted repair
(reminder, this can be caused by numerous conditons and so this Xray presentation may be seen in multiple conditions e.g. Perthes diseas)
Causes of AVN
Primary e.g. Perthes
Idiopathic
Secondary to alcohol/steroid abuse, hyperlipidaemia, thrombophilia
AVN - treatment
If caught pre-collapse, can drill holes in femoral neck and head to extravasate the area with blood and improve supply
Post-collapse - only treatment is THR
How is Trochanteric bursitis/Gluteal Cuff Syndrome caused?
Abductor muscles have a broad tendinous insertion on the greater trochanter that is constantly under a lot of strain, resulting in inflammation and tearing
Trochanteric bursa can also become inflamed in a manner similar to rotator cuff impingement
Where has the thickest hyaline cartilage in the body?
The retropatellar surface
What is the purpose of the fibrocartilagenous menisci in the tibiofemoral joint?
Ensure good communication between the concave condyles of the femur and the relatively flat tibial plateua
Essentially, they act as shock absorbers
What are the functions of the following 4 ligaments
- Anterior cruciate
- Posterior cruciate
- Medial collateral
- Lateral collateral
ACL - prevents abnormal internal rotation of the tibia
PCL - prevents hyperextension and anterior translocation of the tibia
MCL - resists valgus force
LCL - resists varus force and abnormal external rotation of the tibia
How does failure rate of total knee replacement compare to that of partial knee replacement?
Partial knee replacements have a worse outcome in the longer term, as unsurfaced joints can still show progression of OA etc.
What type of movement classically causes meniscal tears?
Twisting force on a loaded knee
Which is longer - the medial or lateral collateral ligament?
How does this affect injury rates?
The medial collateral ligament is longer and is also fixed, making it more prone to injury
The lateral collateral ligament is shorter and more mobile, so it is more resistant to injury
Which meniscus is more commonly damaged?
When does effusion in the knee develop?
The medial meniscus is more commonly damaged, and effusion develops the following day
How will a patient with a meniscal tear present?
What types of meniscal tear are there and which is the most important to watch out for?
Pain
Mechanical symptoms e.g. locking, clicking, possibly difficulty extending the knee (15 degree springy block - indicates Bucket Handle Tear)
May be unable to weight bear
Types of meniscal tear
- Longitudinal -> bucket handle
- Radial -> parrot beak
- Horizontal -> flap tear
What type of movement classically causes an ACL rupture?
Higher rotational force on a planted foot as the individual turns laterally
Reminder - the ACL’s function is to prevent abnormal internal rotation of the tibia
What will a patient with an ACL rupture describe?
Hearing a “pop”
Haemarthrosis within an hour of the injury
Rotator instability, with their knee giving away whenever they turn on the planted foot
How is a PCL rupture typically caused?
By a direct blow to the anterior surface of the tibia when the knee is fully extended, causing forced hyperextension
If a patient has injured their knee, when is it best to examine them?
Wait for 2-7 days after the injury and examine the knee after the initial swelling has gone down
Types of meniscal tear…
Longitudinal tears may progress to…
Radial tears may progress to…
Horizontal tears may progress to…
Longitudinal = Bucket Handle
Radial = Parrot Beak
Horizontal = Flap tear
What clinical test can be used to distinguish between acute and degenerate meniscal tears?
Steinmann’s test - positive in acute, negative in degenerate
Why is the healing potential of the mensici limited?
Because only the outer 1/3rd receives a blood supply
What is the rule of thirds regarding ACL rupture?
ACL ruptures have a highly variable prognosis…
1/3 will be fine and can carry on with their normal lives
1/3 will have to limit certain activities, but can manage
1/3 will have prolonged instability and their knee will give away during everyday tasks
How is ACL rupture treated surgically?
Primary repair of the tendon is not effective
ACL reconstruction using a tendon graft is the most effective treatment
In an ACL tendon graft, where can tendons be harvested from?
Semitendonosus/gracillis tendons
Patellar (higher amount of co-morbidity)
Patellofemoral dysfunction describes anterior knee pain that is made worse when going (uphill/downhill)
Pain is worse going downhill
LCL tears/ruptures are caused by hyperextension and excessive varus force.
What nerve may also be injured?
The common fibular nerve
Damage to the LCL is rare and if it occurs it is usually as a result of multi-ligamentous damage/dislocation
Which artery is also at risk if this is the nature of the injury?
The popliteal artery
Combined knee ligament injury and dislocations are (common/rare)
What are they associated with?
Rare - require at least 3/4 of the ligaments of the knee to be ruptured
High tendency of neurovascular damage (fibular nerve, popliteal artery etc.)
What clinical test can be done to assess the extensor function of the knee?
Straight Leg Raise
Why should steroid injections into the knee be avoided?
Risk of tendon rupture
What is hallux rigidis?
What is the gold standard of treatment? What’s the downside
OA of the first MTP joint
Stiff-soled shoes to prevent MTPJ motio, cheilectomy to remove impinging osteophytes
Gold standard of surgery is arthrodesis - fusion of bones should remove pain with little/no loss of function
Downside of fusion is that patient will no longer be able to wear high heels
What is Mulder’s Click test used to diagnose?
A Morton’s neuroma
compression of the MTP joints either elicits pain in the foot or gives a characteristic “click”
What medication causes inflammation of tendons?
What can this result in?
What should not be done to treat Achilles tendonitis
Quinolones e.g. ciprofloxacin can cause tendonitis
Tendonitis can then lead to tendon rupture
DON’T give a steroid injection around the Achilles tendon as this may cause rupture
What is Simmond’s test?
What does it test for?
Simmond’s test is squeezing of the calf muscle to elicit movement of the foot
If the Achilles tendon has been ruptured, Simmond’s test will be negative
How is a ruptured Achilles tendon treated?
Surgical repair and cast for 8 weeks
OR
Non-surgical management, still casting the foot for 8 weeks but in an equinus position
What is pes planus more commonly known as?
Flat foot
What tendon inserts predominantly into the medial navicular and supports the medial arch of the foot?
How does pathology arise here?
The Tibialis Posterior Tendon
Repeated strain causes inflammation, elongation and potentially rupture
What is pes cavus?
Abnormally high arched foot
