Orthopaedics Flashcards
A six year old boy from Sierra Leone presents with a one week history of a a painful left arm. He is homozygous for sickle cell disease. On examination the child is pyrexial at 40.2 degrees Celsius and there is bony tenderness over the left humeral shaft.
Investigations are:
Haemoglobin: 7.1g/dL
Blood culture: Gram negative rods
X-ray of the left humerus reveals osteomyelitis (destruction of the bony cortex with periosteal reaction).
What is the most likely pathogen?
(A) Escheria coli (B) Non-typhi salmonella (C) Pseudomonas aeruginosa (D) Staphylococcus aureus (E) Parvovirus B19
(B) Non-typhi Salmonella.
Blood and bone infections caused by non-typhi salmonella are typically associated with malaria and homozygous sickle cell disease, especially in children. The reason for the perceived susceptibility is not fully understood but it may be in part due to the haemolysis and subsequent iron availability to the bacteria which is siderophilic in nature.
E.coli and Pseudomonas aeruginosa are not typically linked to sickle cell disease and Staphylococcus aureus is a gram positive coccus.
The haemoglobin level is normal for a child homozygous for sickle cell disease. Therefore aplastic anaemia should not be considered and parvovirus can be ruled out. Parvovirus does not cause osteomyelitis.
A 25 year old man attends the emergency department after being involved in a road traffic accident. He was in the driver’s seat when a lorry in front lost control and became trapped when the dashboard and footwell were pushed forward on impact.
He is currently stable but has significant pain in his right leg. His right leg is shortened and internally rotated, slightly flexed and adducted compared to the left.
What is the diagnosis? (A) Pelvic Ramus Fracture (B) Anterior Hip Dislocation (C) Femoral Shaft Fracture (D) Posterior Hip Dislocation (E) Neck of Femur fracture
(D) Posterior Hip Dislocation
Posterior hip dislocation presents with a shortened and internally rotated leg.
This gentleman has a posterior dislocation of the hip. These injuries are common in road traffic accidents, and particularly when drivers brake hard when recognising a potential collision. On breaking, the knee becomes locked, meaning any force from an impact to the front of the car is translated along the leg and up to the hip joint itself. In a posterior dislocation, the femoral head is now behind the acetabulum, causing the leg to rotate internally to accommodate.
Pelvic fractures typically present with pain on walking or palpation, instability, neurovascular deficits in the limb and signs of damage to pelvic organs (such as haematuria or PR bleeding).
Anterior hip dislocations typically present as abducted and externally rotated. There may be a palpable bulge of he femoral head. They are less common than posterior dislocations but are classically sssociated with hip prostheses.
Signs of femoral shaft fracture include swelling, deformity and shortening of the leg. Given the force of impact required to fracture a femur, there will usually be significant soft tissue injury and bleeding.
Neck of Femur fractures classically present after low-energy impacts in elderly patients. The leg is commonly shortened and externally rotated.
A 65 year old lady presents to her GP complaining of sudden onset pain and paraesthesia in her left leg. On further questioning, she reports that the pain radiates along the posterior thigh and posterolateral aspect of the leg, to the dorsum of her foot and large toe. On examination, you identify sensory loss on the dorsum of her left foot and reduced power upon performing dorsiflecion of her left ankle. Her reflexes remain intact and she has a positive left sided straight leg test.
Which of the following is most likely to be responsible for this presentation?
(A) Sciatic Neuropathy (B) L5 Radiulopathy (C) L4 Radiculopathy (D) Femoral neuropathy (E) S1 Radiculopathy
(B) L5 Radiculopathy
An L5 radiculopathy presents with weakness of hip abduction and foot drop, as seen in this patient. It is typically due to a slipped disc compressing the nerve root. It presents with a positive straight leg raise test and as L5 does not provide any reflex loop, reflexes remain intact.
Sciatic neuropathy which is commonly confused with this would cause a loss of the ankle jerk and plantar response and loss of knee flexion and power below the knee. The femoral nerve supplies the anterior thigh rather than the posterior thigh.
L4 Radiculopathy would cause reduced knee jerk, whilst S1 would affect the ankle jerk.
A 38 year old woman develops lower back pain radiating down her right leg whilst the performing DIY. She describes a sharp, stabbing pain which is worse on movement. Clinical examination reveals a positive straight leg raise test on the right side but otherwise the examination is unremarkable. Appropriate analgesia is prescribed. Of the following, which is the most suitable next step in management?
(A) Check ESR (B) Arrange physiotherapist (C) Refer for MRI (D) Perform a vaginal examination (E) Lumbar spine x-ray
(B) Arrange physiotherapy
This patient has symptoms consistent with a prolapsed disc. Even if this is proven by an MRI Scan, it would not change the initial management as the vast majority of patients improve with conservative treatment such as physiotherapy.
A 32 year old female Sunday rugby league player presents to the emergency department with a painful knee. Upon history taking, she describes feeling a popping sensation in her right knee during the match, and upon clinical examination the knee is swollen, and the patient is unable to fully extend her knee.
Which of the following is the most appropriate initial investigation to request?
(A) Ultrasound scan (B) CT knee (C) X-ray knee (D) MRI knee (E) Arthroscopy
(D) MRI Knee
Based on the patient’s clinical presentation, a meniscal injury is highly likely. MRI is almost 90% sensitive at detecting lateral and medial meniscal tears. It has a higher sensitivity than the other options listed and should be requested for all patients with a suspected meniscal injury.
Also, ultrasound would prove difficult given the degree of swelling and pain that the patient is likely to be in. An x-ray would be indicated in a patient with concurrent arthritis or a longstanding history of repeated meniscal tears.
Arthroscopy is useful in the diagnosis of meniscal tears but should not be considered as the initial investigation of choice.
An 83 year old woman with a history of osteoporosis presented to the emergency department with a suspected hip fracture.
She Is generally frail and has a background of dementia, ischsemic heart disease and COPD. There is no history of hip pain due to osteoarthritis but she does walk with the aid of a walking stick.
She received an x-ray which shows a displaced subcapital fracture of the Femur. What is the most likely surgical treatment option for this type of fracture?
(A) Dynamic hip screw (B) Hemiarthroplasty (C) Kirschner wires (D) Intramedullary nail (E) Total Hip Replacement
(B) Hemiarthroplasty
A subcapital fracture is the commonest type of intracapsular fracture of the proximal Femur.
The intertrochanteric line is the line conencting the greater and lesser trochanter. Any fracture proximal to that line is classed as intracapsular, while any fracture distal is classed as extracapsular.
Since the blood supply is threatened in intracapsular fractures, as a general rule:
(I) Intracapsular femoral fracture = hemiarthroplasty
(II) Extracapsular femoral fracture = Dynamic Hip Screw
A hemiarthroplasty is favoured over a total hip replacement in this case as the patient is
(i) frail, with a background of chronic health problems
(ii) no history of hip osteoarthritis
A 33 year old woman attends her GP with numbness and tingling of both hands which is especially bad at night. On examination she has no weakness of finger flexion, extension or abduction but her pincer grip is weakened. She has mild wasting of the thenar eminence bilaterally and both Tinel’s test and Phalen’s signs are positive in both hands.
Which of the following diseases is she most likely to have in her past medical history which would predispose her to this condition?
(A) Acromegaly (B) Cushing's Disease (C) Rheumatoid Arthritis (D) Nephrotic Syndrome (E) Lymphoedema
(C) Rheumatoid Arthritis
This lady has features of bilateral carpal tunnel syndrome which is a rare presentation and usually due to conditions which expand the interstitial space with soft tissue growth or fluid. While all these conditions are associated with bilateral carpal tunnel syndrome, the most likely in a 33 year old is rheumatoid arthritis. Acromegaly more commonly causes carpal tunnel syndrome after the age of 50.
A 19 year old soldier has just returned from a prolonged marching exercise and presents with a sudden onset, severe pain in the forefoot. Clinical examination reveals tenderness along the second metatarsal. Plain x-rays are taken of the area. These demonstrate callus surrounding the shaft of the second metatarsal. What is the most likely diagnosis?
(A) Stress Fracture (B) Mortons Neuroma (C) Osteochondroma (D) Acute Osteomyelitis (E) Freiberg's Disease
(A) Stress Fracture
A short history of pain together with clinical examination and radiological signs affecting the second metatarsal favour a stress fracture. The fact that callus is present suggests that immobilisation is unlikely to be beneficial. Freiberg’s disease is an anterior metetarsalgia affecting the head of the second metatarsal, it typically occurs in the pubertal growth spurt. The initial injury was thought to be due to stress micro-fractures at the growth plate. The key feature in the history which distinguishes the injury as being stress fracture is the radiology. In Freiberg’s disease, the x-ray changes include joint space widening, formation of bony spurs, sclerosis and flattening of the metatarsal head.
A 55 year old woman comes to see you as she has recently injure her back when picking up some boxes. Her past medical history includes diabetes, chronic kidney disease (CKD) stage 3 and hypertension. She has tried regular paracetamol which has not helped her back pain. She reports passing urine and stool normally and does not have any numbness around the groin.
In view of her comorbidities, which is the most appropriate medication for this patient?
(A) Codeine (B) Ibuprofen (C) Naproxen (D) Tramadol (E) Fentanyl
(A) Codeine
After paracetamol, ibuprofen would usually be recommended for pain, as or the analgesic ladder. However, this patient is known to have chronic kidney disease (CKD), therefore codeine would be the most appropriate next step in management as NSAIDS can worsen a Kidney disease.
A 70 year old woman attends your GP surgery having fallen in her kitchen last week. After the fall, she attended the emergency department and was found to have some bruising but no fractures. She is concerned that she might fall again, and is worried about a fracture occurring in the future. You suggest an assessment of the patient’s fracture risk. Which of the following would be most appropriate on assessing the patient’s fracture risk?
(A) DEXA Scan (B) X-ray of the carpal bones (C) X-ray of the head of the Humerus (D) FRAX Tool (E) Bone Scan
(D) FRAX Tool.
FRAX is an acronym for Fracture Risk Assessment tool. It was developed by the World Health Organisation to evaluate fracture risk in patients. It can be used in people between the ages of 40-90 years old, with or without Bone Mineral Density value.
NICE recommends the use of the FRAX or QFRACTURE tools in the assessing the risk of fragility fractures. As FRAX is the only option available above, this is the correct answer.
Dual energy X-ray absorptiometry (DEXA) is used to measure bone mineral density. In this case, FRAX should be used to assess the patient’s risk initially. As explained below, the results of FRAX may then warrant further investigation with a DEXA Scan.
Performing an X-ray of the carpal bones or head of the humerus would not be appropriate here.
Performing a bone scan (bone scintigraphy) would be inappropriate here, as this will show areas of increased metabolic activity in the bone such as inflammation or malignancy. However it gives no information regarding the patient’s risk of fracture.
