Orthopaedics Flashcards
What is the most superior landmark on the bony pelvis?
Iliac crest
The obturator foramen is positioned … to the acetabulum
Inferior
List some features of the male pelvis
Male: Narrow heart-shaped pelvic inlet Wide pubic arch Everted margins of the pubic arch Narrow and deep greater sciatic notch Ischial spines project more inward Ischial spines tuberosities less everted Smaller distance between the pubic tubercles Wider acetabulum Large and oval obturator foramen Absent pre auricular sulcus Coccyx projected anteriorly and is more fixed Sacrum is long, narrow and curved throughout it's length
List some features of the female pelvis
Female: Wide circular pelvic inlet Narrow pubic arch Not everted margins of the pubic arch Wide and shallow greater sciatic notch Ischial spines project more outwardly More everted ischial tuberosities Greater distance between the pubic tubercles Narrower acetabulum Pre auricular present Straight and flexible coccyx Short, wide and straighter sacrum
When does the ischial rams fuse to the inferior ramus of the pubis?
Between 5-8 years of age
When does the acetabulum fuse?
Between 11-15 years of age
What are the three primary centres of ossification associated with?
The ilium
The ischium
The pubis
How many secondary centres of ossification are there?
5
Where is the primary ossification centre of the femur located?
The midshaft
When does the primary ossification centre of the femur appear?
7th-8th week in utero
How many secondary ossification centres are there in the femur, and where are they?
1) Proximal femur - appears before birth
2) femoral head - 4-6 months old
3) Greater trochanter - 2-5 years old
4) Lesser trochanter - 11 years
What structure is attached around the margin of the acetabulum, but can not be seen on radiographs?
Acetabular labrum
What are the proximal and distal attachments of the iliofemoral ligament?
Proximal: anterior inferior iliac spine & margin of the acetabulum
Distal: intertrochanteric line
Name the 3 ligaments associated with the hip joint
Iliofemoral
Ischiofemoral
Pubofemoral
In what position is the hip most unstable, and why?
Flexion and medial rotation - the head of the femur is mostly out of the acetabulum and capsule, and the ligaments are all unwound so are ‘loose’
What is the embryological role of the ligament teres?
Transmits blood vessels to the femoral head
Recent research has suggested that the ligamentum treres plays a role in preventing …?
Dislocation of the femoral head, and initiating a reflex response to prevent excessive movements
Where does the major blood supply to the head of the femur enter?
The capsule at the base of the femoral neck
An intra-capsular fracture of the femoral head disrupts femoral head vessels and can result in…
Avascular necrosis
How is an intra-capsular fracture of the femoral head treated?
Replacement of the entire femoral head (usually a heme-arthroplasty), to prevent bleeding and avascular necrosis
Which action des iliopsoas perform?
Hip flexion
What gluteus muscles are involved in abduction?
Gluteus medius and Gluteus minimus
What action does gluteus maximums perform?
Hip extension
What action does performis perform?
Lateral rotation
What is the nerve supply of gluteus medius?
Superior gluteal nerve
Why is the superior gluteal nerve clinically important?
It is vulnerable during hip surgery. Injury to the nerve and resulting paralysis of gluteus medium results in a positive Trendelenburg sign
Action of rectus femurs?
Hip Flexion
Action of adductor longs, adductor braves and the adductor portion of adductor magnus?
Hip Flexion and adduction
Action of gracilis?
Adduction
Action of hamstring portion of adductor magnus?
Adduction and hip flexion
Action of the hamstrings?
Hip Extension
Action of gluteus medium and minimum?
Abduction
Nerve supply of rectus femurs?
Femoral nerve
Nerve supply of adductor longs, adductor braves, adductor portion of adductor Magnus and gracilis?
Obturator nerve
Nerve supply of the hamstring portion of adductor Magnus?
Tibial nerve
nerve supply of the hamstrings?
Sciatic nerve
Which 3 muscles make up the true hamstring group?
Biceps femoris
Semitendonous
Semimembranous
Which muscle is considered a partial hamstring, and why?
Adductor magnus
A section inserts on the ischial tuberosity, and assists in hip extension
When does the primary ossification centres for the tibia appear?
7-8 weeks in utero
Where are the 3 secondary ossification centres in the tibia?
1) Proximal epiphysis - around birth
2) Distal epiphysis - 3-10 months old
3) Ischial tuberosity - 10 years old
When does the primary ossification centre of the fibula appear?
8 weeks in utero
Where are the 2 secondary centres of ossification in the fibula?
1) Distal epiphysis - 1-2 years old
2) Proximal epiphysis - 3-5 years old
Describe the difference in shapes between the 2 menisci?
Medial meniscus - C-shaped
Lateral meniscus - circular
Describer the differences between attachments of the medial and lateral menisci?
Medial - blends into the ACL and the medial collateral ligament
Lateral - not attached to lateral collateral ligament
How is the knee joint ‘unlocked’ after standing?
Contraction of popliteus laterally rotates the femur on the tibia
What is the clinical importance of the ‘unhappy triad of the knee’
Unhappy triad: ACL, medial meniscus and medial collateral ligament. If the medial collateral ligament is torn, this subsequently leads to tearing of the medial meniscus and sometimes the ACL
What is the function of the quadriceps muscles?
Knee extension
What is the function of gastrocnemius?
Knee flexion
What is the function of the hamstrings?
Knee flexion
What is the function of sartorial?
Flexion
What is the function of popliteus?
Lateral rotation
Nerve supply of the quadriceps?
Femoral nerve
Nerve supply of gastrocnemius?
Tibial nerve
Nerve supply of the hamstrings?
Sciatic nerve
Nerve supply of sartorial?
Femoral nerve
Nerve supply of popliteus?
Tibial nerve
Which 4 muscles make up the quadriceps group?
1) Rectus femoris
2) Vastus lateralis
3) Vastus intermedius
4) Vastus medialis
When does the external iliac artery become the femoral artery?
When it passes deep to the inguinal ligament
When does the femoral artery become the popliteal artery?
As it passes through the adductor hiatus and enters the popliteal fossa
What is the fovea capitis?
A small depression on the femoral head which is the site of attachment for the ligamentum teres
What are the attachment points of the ischiofemoral ligament?
Ischium to the inner aspect of the intertrochanteric crest
Name the 3 internal supporting structures of the hip
1) Transverse acetabular ligament (bridges the acetabular notch between the lunate surface)
2) Acetabular labrum - cartilage which blends with the TAL to surround the edge of the acetabulum
3) Ligamentum teres
What the functions of the superior and inferior gemellus?
Rotation
What are the attachment points of the superior gemellus?
Ischial spine to femur
What are the attachment points of the inferior gemellus?
Ischial tuberosity to femur
Which muscle is largely associated with sciatica and why?
Piriformis - the sciatic nerve passes right next to/through it
What is the nerve supply of the anterior thigh compartment?
Femoral nerve
What muscles make up the anterior thigh compartment?
Quadiceps Femoris muscles (rectus femoris, vastus lateralis, vastus intermedius and vastus medialis)
Iliopsoas (formed from posts major, minor and iliac)
Sartorius
Pectineus
Which nerve supplies the medial thigh compartment?
Obturator nerve
Which muscles make up the medial thigh compartment?
Adductor longus
Adductor brevis
Adductor magnus
Gracilis
Which nerve supplies the posterior compartment of the thigh?
Sciatic nerve
Which muscles make up the posterior thigh compartment?
Biceps femoris
Semitendonous
Semimembranous
Where do all three hamstrings originate from?
Ischial tuberosity
Name the 3 borders of the femoral triangle
Inguinal ligament
Medial border of sartorial
Medial border of adductor longus
What structures pass through the femoral triangle?
Femoral artery
Femoral nerve
Femoral vein
Which branch of the femoral artery appears in the femoral triangle?
Profundus femoris
What is the clinical relevance of the femoral artery branch point in the femoral triangle?
Site of femoral hernias
MSK disorders account for about ??% of GP consultations
25%
What is the biggest cause of disability?
Limb trauma
How does NICE define OA?
“a syndrome of joint pain accompanied by varying degrees of functional limitation and reduced quality of life”
OA affects women to men in a ??:1 ratio
1.7
What percentage of over 45 year olds suffer from hip OA?
11
What percentage of over 45 year olds suffer from knee OA?
18
Name some of the risk factors for primary OA
Age
Genetics
Female sex
Obesity
Name some of the risk factors for secondary OA
Trauma Infection SUFE Perthe's inflammation (RA) Gout
Describe articular cartilage
A firm, flexible connective tissue made of chondrocytes bound in an ECM. The ECM is 65-80% water, but also contains type 2 collagen and proteoglycans.
Describe chondrocytes
Chondrocytes are avascular cells which are exclusive to articulate cartilage, nourished via the synovial fluid. Their function is to produce the ECM and enzymes.
Name 3 functions of articular cartilage
Structure
Load bearing
Reduce friction
Describe the pathology of OA
Inappropriate water retained in the ECM –> water content increased –> all other cells decrease in number –> biochemical and structural changes occur –> inferior load bearing and increased friction
Describe the 2 layers and functions of hyaline cartilage
Superficial - smooth surface with parallel collagen fibres and few chondrocytes. Function: decreases joint friction
Deep - perpendicular collagen fibres with greater cell numbers. . Function: load-bearing.
What are the 4 cardinal signs of OA on an x-ray
1) Joint space narrowing
2) Osteophytes
3) Subchondral sclerosis
4) Bone cysts
A working diagnosis of OA can be made without an x-ray if the patient meets the following criteria:
1) Age >45
2) Chronic joint pain (>3 months) which worsens with use
3) Morning stiffness <30 minutes
4) An alternative diagnosis is unlikely
About ?/? of OA patients develop progressive disease
1/3
Conservative management of OA includes…
Patient education Physiotherapy and exercise Lifestyle changes - weight loss, smoking cessation Walking aids Simple analgesia
Surgical management of OA includes…
Joint arthroplasty
Joint arthrodesis (in joints which require little movement)
Osteotomy
Cartilage procedures
List some differences between paediatric and adult fractures
Paediatric fractures:
- Heal more quickly
- Have less morbidity with bed rest (e.g. no chest infection, DVT, pressure sores)
- Have a thick periosteum which allows conservative management
- Can be left malaligned due to remodelling ability
Why are physeal plate injuries important before skeletal maturity?
They can stunt growth
Describe the management of forearm fractures in children
- Controlled in cast
- Manipulation under anaesthesia
- K-wires/flexible nails
Describe the management of femoral fractures in children
- Bed traction
2. Flexible nails (in those who can’t tolerate bed traction)
When would a tibial or femoral fracture be a red flag symptom in a child?
If the child is not mobilising
What age do the physeal growth plates usually fuse?
12-14 years old
List some of the complications of a physical growth plate fracture?
- Increased risk of growth problems
- Partial/complete growth arrest - can lead to angular deformities (varus/valgus legs) or leg length differences
- Intra-articular involvement can predispose to arthritis
How are physical fractures classified?
Salter-Harris Classification system
How would you manage a Salter-Harris type I or II fracture?
Conservative management e.g. cast or MUA
How would you manage a Salter-Harris type III or IV fracture?
Surgical reduction and fixation
What structures do you need to avoid when placing a screw in a Salter-Harris fracture?
Growth plate
Intra-articular structures
What type of Salter-Harris fracture is most common?
Type II
What neurovascular structures would you be concerned about in a supracondylar fracture of the humerus?
Brachial artery
Median nerve
Ulnar nerve
What would be your 4 main differential diagnoses in a limping child under 2 years old?
Infection
Malignancy
Non-accidental injury
Developmental Dysplastic Hip
What would be your 4 main differential diagnoses in a limping child between 3 and 8 years old?
Infection
Malignancy
Non-accidental injury
Perthes Disease
What would be your 4 main differential diagnoses in a limping child between 9 and 15 years old?
Infection
Malignancy
Non-accidental injury
Slipped Capital Femoral Epiphysis
What is the most common musculoskeletal disorder in newborns?
Developmental hip dysplasia
What is the incidence of hip dysplasia in newborns?
1 in 1000
The hips are bilaterally affected in ..% of hip dysplasia cases
20
List the risk factors for hip dysplasia
Female First born Family history Breech birth Oligohydramnios
What tests can be used to screen babies for DDH?
Barlow’s test
Ortolani’s test
Leg length difference testing
Hip abduction testing (limited in DDH)
What imaging should you perform in a baby who is at high risk of DDH?
Ultrasound
Describe the pathophysiology of DDH
DDH is a disorder of abnormal development resulting in acetabular dysplasia, leading to subsequent laxity or dislocation of the hip.
Describe the management options for DDH
- Spica casting (in those 6-18 months)
- Open reduction and case (in those >18 months or where closed reduction has failed)
- Combined femoral head and/or pelvic osteotomy (surgery to shift femoral head into acetabulum, in those with failed treatment, or >24 months of age/late diagnosis)
What is the incidence rate of SUFE?
10 in 100000 children affected
When are children likely to present with SUFE?
Normally just before their pubertal growth spurt/skeletal maturity - girls usually present at 12.2 and boys at 13.4
Describe the risk factors associated with SUFE
Obesity Endocrine disorder Males (male: female 3:2) African Americans Pacific Islanders
Describe the pathophysiology of SUFE
SUFE is a weakness of the proximal femoral physics, which leads to slippage of the epiphysis relative to the femoral neck
Describe how SUFE would typically present
In an 8-15 year old
Commonly with obesity and//or endocrinopathy
Shortened external rotation of hip
Loss of internal rotation and abduction
What imaging would you perform in a child with suspected SUFE?
‘Frog leg’ lateral X-ray - have child sit cross legged
The line of ….. is useful in detecting an early SUFE
Klein
What are some of the complications of an undetected SUFE?
Avascular necrosis
Femoral head collapse
Death of the femoral head
Describe the management options for a child with SUFE
- Pin in situ without attempt to reduce
2. Open realignment if screw can’t be inserted
In Edinburgh, it is routine practice to prophylactically fix the other hip in a child with SUFE (true or false)
True - 50% of children with SUFE will slip on the contralateral side within 1 year
What is the incidence of Perthes disease?
1 in 1000 children affected
The hips are bilaterally affected in ..% cases of Perthes disease
12%
List the risk factors for Perthes disease
Positive family history
Low birth weight
Exposure to second hand smoke
Male (5:1 male: female)
Describe the pathophysiology of Perthes disease
Idiopathic avascular necrosis of the proximal femoral epiphysis - disruption of the femoral head blood supply which leads to bone collapse and subsequent remodelling
Which factors would make the prognosis of Perthes disease worse?
Age >6 at presentation
Female sex
Decreased hip range of motion at presentation
Describe the typical clinical features of Perthes disease
Insidious limp (Trendelenburg gait)
Hip and/or knee pain
Loss of internal rotation and abduction
Leg length differences (in advanced disease)
What imaging test would you perform in a child with suspected Perthes?
X-ray to view bone collapse. An MRI can be used if nothing is seen on x-ray to rule out other pathologies.