Lower Extremity Disorders Flashcards
What makes the hip a more stable joint than the shoulder?
Acetabulum is a deep socket with much more coverage of femoral head
How is the hip joint different than the shoulder joint?
Weight bearing
Where is the sciatic nerve most vulnerable to pelvic fractures?
Sciatic notch
Where is the sciatic nerve most vulnerable to posterior dislocations?
Distal to sciatic notch
How does hip pain present?
Groin and anterior thigh
Describe avascular necrosis of the hip
- Aseptic necrosis of hip
- Results from loss of blood supply to femoral head
- Males
- 20-40 yo
Treatment of AVN of the hip
- Restrict weight bearing and activity to prevent collapse
- Long term prognosis is poor usually requires total hip arthroplasty as OA progresses
Who is affected by OA of the hip?
- Under 45 yo, MC in men
- Over 55 yo, MC in women
What is the sign of end stage OA of the hip?
Pain at rest
Post-op care of total hip arthroplasty
- Rapid mobilization, wt bearing as tolerated w/crutches or a walker
- Anticoag
- Alternating compression sleeve and stocking
What is the MC approach to total hip arthroplasty?
Posterior - less risk of infection, quicker recovery
Describe trochanteric bursitis
- Bursa overlies greater trochanter and can get irritated
- Pain over GT aggravated by lying on the affected side
What is the most likely cause of snapping hip?
Tight IT band that catches over greater trochanter with movement
What makes the knee inherently unstable? What keeps it stable?
- Intrinsic bony configuration
- Surrounding network of soft tissue
What is the bony anchor of the extensor mechanism in the knee?
Patella
What is the largest sesamoid bone in the body?
Patella
What are the extrinsic ligaments of the knee?
MCL (femur and tibia)
LCL (femur and fibula)
What are the intrinsic ligaments of the knee?
ACL (resists anterior translation on tibia)
PCL (resists posterior translation on tibia)
MOI for ACL injury?
- Valgus force to ER knee w/foot planted
- Hyperextension in IR
MOI for PCL injury?
- Knee flexed
- Anterior to posterior translation of joint
What is the extensor apparatus of the knee and what does it do?
Straightens knee, prevents buckling
- Quad muscle and tendon
- Patella and tendon
- Tibial tubercle
When ordering x-rays of the knee, what views should be obtained?
AP, lateral, tunnel view
Sunrise if tracking patella
What x-ray view is best if you suspect OA in a patient over 40?
- AP view in standing position
- Lets you see joint space narrowing better
Describe MCL fibers
- Posterior fibers are taut in extension
- Anterior fibers are taut in flexion
MCL is primary stabilizer to what type of stress?
Valgus (lateral) stress
MOI of MCL injury?
Lateral or valgus stress (often w/foot planted)
MCL injury grading
Grade I: 1-5 mm laxity
Grade II: 5-10 mm laxity
Grade III: Over 10 mm laxity
MOI of LCL injury?
Varus stress to medial aspect of knee
What is the most important single ligamentous stabilizer in the knee?
ACL
ACL can be reconstructed with what type of grafts?
Patellar, semitendinosis, gracilis
What is the strongest ligament of the knee?
PCL
MOI of knee meniscal injuries
- Usually a twisting injury
- In older patients may be as simple as squatting down
Patients don’t like to have their knees touching in which knee injuries?
Meniscal
PE of meniscal injuries shows:
- Positive McMurray’s sign
- Positive Apley grind test
Subtotal menisectomy may predispose patients to what?
OA
How does a meniscal cyst of the knee present?
- Similar to meniscal tear but usually with a painful lump along joint line
- Requires a more extensive surgery
What is a discoid meniscus? How does it present and how is it treated?
- Congenitally abnormal meniscus (too big and not C shaped)
- Can cause a painful click
- Arthroscopy to remove excess meniscus
What is chondrocalcinosis? How is it treated?
- Pseudogout
- Calcium pyrophosphate dihydrate deposition in mensicus
- Arthroscopic partial or complete menisectomy
What is a plica? Definitive treatment?
- Silky membrane of tissues within the fetus’s knee
- Usually dissolves at birth
- 30% of people keep it (medial side of knee)
- Some thicken and present similar to torn meniscus
- Arthroscopic debridement
What is a Baker’s cyst?
- Not truly a cyst but a collection of fluid in a normally occurring bursa behind knee
- Pts w/pain usually have torn meniscus due to synovial fluid being pumped out of the knee into the bursa
What is osteochondritis dissecans? Who is affected?
- Subchondral bone develops AVN
- Mostly males, young adults
- X-ray shows a lucency over medial femoral condyle
AVN of the knee
- Presents much like osteochondritis dissecans
- X ray shows radiolucent defect
- If no response to conservative tx, patient may need TKR
Chondromalacia of the knee
- Extensor apparatus dysfunction
- Softening of articular cartilage
All patellofemoral disorders influence what?
Q angle (indicator of how patella tracks)
Q angle in males vs. females
Males usually small angle
Females usually large angle
Patellofemoral disorders affect who?
Young females usually athletes or those who ride horses
PE of patellofemoral disorders
- Crepitus
- Large Q angle
- Apprehension sign w/lateral displacement of patella
- Positive squeeze test
Describe patella tendinitis
- Jumpers knee (bball players)
- Pain over tendon worse w/stairs and jumping
Where does bursitis in the knee occur MC?
Pre-patellar (traumatic injury)
Pes anserine
Compartments of the knee
- Medial
- Lateral
- Patellofemoral
Septic arthritis of knee
- Direct invasion of joint space by bacteria
- MC S aureus
- Young pts MC N. gonorrheae
Early prosthetic joint infection (within 3 months) is MC caused by which bacteria?
S aureus
Delayed prosthetic joint infections (3-24 months) are MC caused by which bacteria?
CoNs and gram negative aerobes
Septic arthritis presenting triad
Fever, pain, impaired ROM
Hallux valgus deformity
- Bunion
- Enlarged bursa is the bump
What is Tailor’s bunion?
Bunion on 5th MT
What is pes planus? Treatment?
- Overpronation of foot (flat feet)
- Orthotics to correct flat foot deformity
Treatment of plantar fasciitis?
- Orthotics (heel pads or cups do NOT work)
- Avoid walking barefoot
What is Morton’s neuroma?
Fibrosis of interdigital nerve between 3rd and 4th toes
Hammer toes
- Deformity of 2nd, 3rd, 4th toes
- Toe is bent at middle joint so it resembles hammer
- If left untreated, can become fixed and require surgery
What causes hammer toes?
Shoes that don’t fit properly and/or muscle imbalance
Ankle sprain MOI
Inversion type injury
High ankle sprain MOI
Twisting or rotational injury
How does posterior tibial tendon injury occur?
Excessive pronation
Cortisone injections of achilles tendinitis
NEVER (increases incidence of rupture)
MOI achilles rupture
- Explosive plantar flexion
- Forced dorsiflexion
PE of achilles rupture
Positive Thompson test
Positive Thompson test?
Achilles tendon rupture
Plantaris tendon rupture
- Long thin muscle that traverses through calf
- Same presentation as Achilles rupture
What is retrocalcaneal bursitis?
- Pump bump (Haglund’s deformity)
- Positive 2 finger squeeze test
Who is affected by achilles rupture?
- 40 yo or older males
- Weekend warrior types
- Basketball, racquet sports
Presentation of Achilles rupture?
Feels like someone hit it with a baseball bat
