Orthopaedics 2 Flashcards
What are FRAX and QFracture scores?
- FRAX (fracture risk assessment tool) and QFracture scores estimate the liklihood of a fragility fracture (due to osteoporosis) within the next 10 years
- A FRAX score of 10% or greater warrants a DEXA scan
FRAX
- estimates the 10-year risk of fragility fracture
- valid for patients aged 40-90 years
- based on international data so use not limited to UK patients
- assesses the following factors: age, sex, weight, height, previous fracture, parental fracture, current smoking, glucocorticoids, rheumatoid arthritis, secondary osteoporosis, alcohol intake
- bone mineral density (BMD) is optional, but clearly improves the accuracy of the results. NICE recommend arranging a DEXA scan if FRAX (without BMD) shows an intermediate result
QFracture
- estimates the 10-year risk of fragility fracture
- developed in 2009 based on UK primary care dataset
can be used for patients aged 30-99 years (this is stated on the QFracture website, but other sources give a figure of 30-85 years)
- includes a larger group of risk factors e.g. cardiovascular disease, history of falls, chronic liver disease, rheumatoid arthritis, type 2 diabetes and tricyclic antidepressants
Who should be assessed using the FRAX score? When should someone get a dexa scan?
All women aged >= 65 years and all men aged >= 75 years should be assessed. Younger patients should be assessed in the presence of risk factors, such as:
- previous fragility fracture
- current use or frequent recent use of oral or systemic glucocorticoid
- history of falls
- family history of hip fracture
- other causes of secondary osteoporosis
- low body mass index (BMI) (less than 18.5 kg/m²)
- smoking
- alcohol intake of more than 14 units per week for women and more than 14 units per week for men.
There are some situations where NICE recommend arranging BMD assessment (i.e. a DEXA scan) rather than using one of the clinical prediction tools:
- before starting treatments that may have a rapid adverse effect on bone density (for example, sex hormone deprivation for treatment for breast or prostate cancer).
- in people aged under 40 years who have a major risk factor, such as history of multiple fragility fracture, major osteoporotic fracture, or current or recent use of high-dose oral or high-dose systemic glucocorticoids (more than 7.5 mg prednisolone or equivalent per day for 3 months or longer).
What is a positive Froment’s sign?
Patient cannot grip paper placed between thumb and index finger. There is weakness of the adductor pollicus innervated by the ulnar nerve which would keep the IP joint relatively straight; instead, the FPL muscle which is innervated by the median nerve is substituted for the AP and will cause the IP joint to go into a hyperflexed position.
Where is the ulnar nerve typically damaged?
elbow (cubital tunnel syndrome) or at the wrist (Guyons canal syndrome)
Which nerve roots make up the tibial nerve?
L4-S3
What is the function of the tibial nerve?
Sensory: Innervates the skin of the posterolateral side of the leg, lateral side of the foot, and the sole of the foot.In the popliteal fossa, the tibial nerve gives off cutaneous branches. These combine with branches from the common fibular nerve to form the sural nerve. This sensory nerve innervates the skin of the posterolateral side of the leg and the lateral side of the foot.
The tibial nerve also supplies all the sole of the foot via three branches:
- Medial calcaneal branches: These arise within the tarsal tunnel, and innervate the skin over the heel.
- Medial Plantar Nerve: Innervates the plantar surface of the medial three and a half digits, and the associated sole area.
- Lateral Plantar Nerve: Innervates the plantar surface of the lateral one and a half digits, and the associated sole area.
Motor: Innervates the posterior compartment of the leg:
Deep
- Popliteus – Laterally rotates the femur on the tibia to unlock the knee.
- Flexor Hallucis Longus – Flexes the big toe and plantar flexes the ankle.
- Flexor digitorum Longus – Flexes the other digits and plantar flexes the ankle.
- Tibialis Posterior – Inverts the foot and plantar flexes the ankle.
Superficial
- Plantaris – Plantar flexes the ankle.
- Soleus – Plantar flexes the ankle.
- Gastrocnemius – Plantar flexes the ankle and flexes the knee.
What are the roots and functions of the obturator nerve?
Roots: L2, L3, L4.
Motor Functions: Innervates the muscles:
- obturator externus
- pectineus
- adductor longus
- adductor brevis
- adductor magnus
- gracilis
Sensory Functions: Innervates the skin over the medial thigh.
What are the roots and functions of the femoral nerve?
Roots: L2, L3, L4.
Motor Functions: Innervates the muscles:
- Illiacus
- pectineus
- sartorius
- all the muscles of quadriceps femoris.
Sensory Functions: Innervates the skin on the anterior thigh and the medial leg.
What are the branches of the sacral plexus?
A useful memory aid for the major branches of the sacral plexus is ‘Some Irish Sailor Pesters Polly’. This stands for:
- Superior Gluteal
- Inferior Gluteal
- Sciatic
- Posterior cutaneous nerve of thigh
- Pudendal
What’s the course of the superior gluteal nerve? What are the roots, motor and sensory functions?
The superior gluteal nerve leaves the pelvis via the greater sciatic foramen, entering the gluteal region superiorly to the piriformis muscle. It is accompanied by the superior gluteal artery and vein for much of its course.
Roots: L4, L5, S1.
Motor Functions: Innervates the:
- gluteus minimus
- gluteus medius
- tensor fascia lata
Sensory Functions: None.
What’s the course of the inferior gluteal nerve? What are the roots, motor and sensory functions?
The inferior gluteal nerve leaves the pelvis via the greater sciatic foramen, entering the gluteal region inferiorly to the piriformis muscle.
It is accompanied by the inferior gluteal artery and vein for much of its course.
Roots: L5, S1, S2.
Motor Functions: Innervates gluteus maximus.
Sensory Functions: None.
What’s the course of the pudendal nerve? What are the roots, motor and sensory functions?
This nerve leaves the pelvis via the greater sciatic foramen, then re-enters via the lesser sciatic foramen. It moves anterosuperiorly along the lateral wall of the ischiorectal fossa, and terminates by dividing into several branches.
Roots: S2, S3, S4
Motor Functions: Innervates the skeletal muscles in the perineum, the external urethral sphincter, the external anal sphincter, levator ani.
Sensory Functions: Innervates the penis and the clitoris and most of the skin of the perineum.
(Tip – an easy way to remember the functions of the pudendal nerve is S2, S3, S4 keeps poo off the floor!)
What are the roots, motor and sensory functions of the sciatic nerve?
Roots: L4, L5, S1, S2, S3
Motor Functions:
Tibial portion – Innervates the muscles in the posterior compartment of the thigh apart from the short head of the biceps femoris (biceps femoris, semimembranosus and semitendinosus), and the hamstring component of adductor magnus (remaining portion of which is supplied by the obturator nerve). Innervates all the muscles in the posterior compartment of the leg and sole of the foot.
Common fibular portion – Short head of biceps femoris, all muscles in the anterior and lateral compartments of the leg and extensor digitorum brevis.
Sensory Functions:
Tibial portion: Innervates the skin on the posterolateral and medial surfaces of the foot as well as the sole of the foot.
Common fibular portion: Innervates the skin on the anterolateral surface of the leg and the dorsal aspect of the foot.
What are the sensory nerves of the sciatic nerve?
- Sural nerve (formed by branches of the common fibular and tibial nerves)- posterior/lateral lower leg and foot
- Deep fibular nerve (a branche of the common fibular nerve)- outer upper part of lower leg
- Superficial fibular nerve (a branch of the common fibular nerve)- lower lateral/anterior lower leg and dorsum of foot
- Medial calcaneal branches (branches of the tibial nerve)- back of heel
What are the muscles within the foot and which nerves innervate them?
Dorsal aspect
- extensor digitorum brevis (deep fibular nerve)
- extensor hallucis brevis (deep fibular nerve)
Plantar side (medial plantar nerve or the lateral plantar nerve, which are both branches of the tibial nerve)
Layer 1 (most superficial)
- Abductor Hallucis (medial plantar nerve)
- Flexor Digitorum Brevis (medial plantar nerve)
- Abductor Digiti Minimi (lateral plantar nerve)
Layer 2
- Quadratus Plantae (lateral plantar nerve)
- Lumbricals ( most medial- medial plantar, lateral 3- lateral plantar)
Layer 3
- Flexor Hallucis Brevis (medial plantar)
- Adductor Hallucis (deep branch of lateral plantar)
- Flexor Digiti Minimi Brevis (superficial branch of lateral plantar)
Layer 4
- Plantar Interossei (lateral plantar nerve), unipennate
- Dorsal Interossei (lateral plantar nerve), bipennate
What’s the medical name for club foot?
Talipes equinovarus
Is talipes equinovarus more common in men or women? What’s the incidence? What’s it associated with?
- M:F 2:1
- 1 per 1,000 births. Around 50% of cases are bilateral.
Most commonly idiopathic. Associations include:
- spina bifida
- cerebral palsy
- Edward’s syndrome (trisomy 18)
- oligohydramnios
- arthrogryposis
How do you diagnose and manage talipes equinovarus?
The diagnosis is clinical (the deformity is not passively correctable) and imaging is not normally needed.
Management
- in recent years there has been a move away from surgical intervention to more conservative methods such as the Ponseti method
- the Ponseti method consists of manipulation and progressive casting which starts soon after birth.
- The deformity is usually corrected after 6-10 weeks.
- An Achilles tenotomy is required in around 85% of cases but this can usually be done under local anaesthetic
- night-time braces should be applied until the child is aged 4 years.
- The relapse rate is 15%
What is the pathophysiology of talipes equinovarus?
- contraction of achilles and tightness of skin and medial flexors.
- deformities:
CAVE
Cavus of midfoot
Adduction of forefoot
Varus of hindfoot
Equinus of hindfoot (plantarflexion)
What is the most common cause of heel pain in an adult? Where is the pain worst?
Plantar fasciitis
The pain is usually worse around the medial calcaneal tuberosity.
How do you manage plantar fasciitis?
- Plantar fasciitis is best managed initially with rest, stretching and weight loss if overweight
- wear shoes with good arch support and cushioned heels
- insoles and heel pads may be helpful
What is trigger finger associated with?
Associations* (idiopathic in the majority)
- more common in women than men
- rheumatoid arthritis
- diabetes mellitus
*evidence for repetitive use is poor
Which fingers is trigger finger most common in?
Thumb
Middle
Ring
How do you treat trigger finger?
- immobilisation
- injection of steroid
- needling
- decompression
What are the featurs of meniscal tear and what imaging should you use?
Typically result from twisting injuries
Features
- pain worse on straightening the knee
- displaced meniscal tears may cause knee locking
- tenderness along the joint line
- Thessaly’s test - weight bearing at 20 degrees of knee flexion, patient supported by doctor, postive if pain on twisting knee
MRI
What are the features of cauda equina?
- lower back pain
- urinary incontinence/retention
- reduced sensation in the perianal area
- decreased anal tone
When should you x-ray a suspected ankle injury?
Ottawa ankle rules to try and minimise the unnecessary use of x-rays.
An ankle x-ray is required only if there is any pain in the malleolar zone and any one of the following findings:
- bony tenderness at the lateral malleolar zone (from the tip of the lateral malleolus to include the lower 6 cm of posterior border of the fibular)
- bony tenderness at the medial malleolar zone (from the tip of the medial malleolus to the lower 6 cm of the posterior border of the tibia)
- inability to walk four weight bearing steps immediately after the injury and in the emergency department
Sensitivity nearly 100%
What are the different types of ankle fractures?
Unimalleolar 68%
Bimalleolar 25%
Trimalleolar 7%
Open 2%
What should the gap around the talus be on a mortise x-ray?
4mm
Which classification system is used to describe fibular breaks?
Weber classification
Related to the level of the fibular fracture.
- Type A is below the syndesmosis
- Type B fractures start at the level of the tibial plafond and may extend proximally to involve the syndesmosis
- Type C is above the syndesmosis which may itself be damaged
A subtype known as a Maisonneuve fracture may occur with spiral fibular fracture that leads to disruption of the syndesmosis with widening of the ankle joint, surgery is required.
The syndesmosis is the region between the distal tibia and fibula, between the top of the talus and 2.5cm proximal to that.
How do you treat ankle fractures?
Weber A or B, below knee cast 4-6 weeks, if they are diabetic tell them not to weight bear.
Weber C use syndesmosis screws
What is the recommended first line method of analgesia for NOF fractures?
Fascia iliaca compartment block
The Fascia iliaca compartment is an area of potential space that lies between the posterior surface of the fascia iliaca and the anterior surface of the iliacus and posts major muscles. Local anaesthetic injected into this potential space affects the femoral, obturator and lateral femoral cutaneous nerves. The aim of this is to reduce the use of opioids analgesics e.g. morphine, which is particularly helpful in elderly patients who are often more susceptible to their side effects.
What scale is used to classify the severity of open fractures?
Gustillo and Anderson
Type I
- wound ≤1 cm, minimal contamination or muscle damage
Type II
- wound 1-10 cm, moderate soft tissue injury
Type IIIA
- wound usually >10 cm, high energy, extensive soft-tissue damage, contaminated
- adequate tissue for flap coverage
- farm injuries are automatically at least Gustillo IIIA
Type IIIB
- extensive periosteal stripping, wound requires soft tissue coverage (rotational or free flap)
Type IIIC
- vascular injury requiring vascular repair, regardless of degree of soft tissue injury
How do you manage open fractures?
- Immobilise the fracture including the proximal and distal joints
- Carefully monitor and document neurovascular status, particularly following reduction and immobilisation
- Manage infection including tetanus prophylaxis (> chrs before surgery)
- IV broad spectrum antibiotics for open injuries
- As a general principle all open fractures should be thoroughly debrided ( and internal fixation devices avoided or used with extreme caution)
- Open fractures constitute an emergency and should be debrided and lavaged within 6 hours of injury
- need definitive coverage (e.g flap) + fixation within 72 hours
What are the features of discitis?
- Back pain
- General features: pyrexia, rigors, sepsis
- Neurological features if epidural abscess develops
What are the causes of discitis?
- Bacterial: Staphylococcus aureus is the most common cause
- Viral
- TB
- Aseptic
How do you diagnose and treat a patient with discitis?
Diagnosis
Imaging:
- MRI has the highest sensitivity
- CT guided biopsy may be required to guide antimicrobial treatment
Treatment
- The standard therapy requires six to eight weeks of intravenous antibiotic therapy
- Choice of antibiotic is dependent on a variety of factors. The most important factor is to identify the organism with a positive culture (e.g. blood culture, or CT guided biopsy)
Further investigation:
Assess the patient for endocarditis e.g. with transthoracic echo or transesophageal echo. Discitis is usually due to haematogenous seeding of the vertebrae implying that the patient has had a bacteraemia and seeding could have occurred elsewhere
What’s the pathology for lumbar spinal stenosis?
Degenerative disease is the commonest underlying cause. Degeneration is believed to begin in the intervertebral disk where biochemical changes such as cell death and loss of proteoglycan and water content lead to progressive disk bulging and collapse. This process leads to an increased stress transfer to the posterior facet joints, which accelerates cartilaginous degeneration, hypertrophy, and osteophyte formation; this is associated with thickening and distortion of the ligamentum flavum. The combination of the ventral disk bulging, osteophyte formation at the dorsal facet, and ligamentum flavum hyptertrophy combine to circumferentially narrow the spinal canal and the space available for the neural elements. The compression of the nerve roots of the cauda equina leads to the characteristic clinical signs and symptoms of lumbar spinal stenosis.`
