I85PREP
⌘ K
AOBOS Orthopedics study materials
AOBOS Orthopedics study resources

AOBOS Orthopedics practice questions

One question at a time. Build your AOBOS Orthopedics understanding.

First 50 of 199 questions. Each one lists the choices, the correct answer, and an explanation. The checker at the top of this page saves progress in this browser when it is available.

Continue in the practice tool above to load more questions, 50 at a time.

Question 1General Orthopedics and Osteopathic Principles

In the sequence of secondary fracture healing, which process occurs first?

  1. Hematoma and inflammation Correct answer.
  2. Soft callus formation and bridging
  3. Bone remodeling and reshaping
  4. Hard callus formation and union

Explanation

Secondary fracture healing begins with vessel rupture, hematoma formation, and an inflammatory cell response. Soft callus, hard callus, and remodeling follow in that order.

Question 2General Orthopedics and Osteopathic Principles

Which finding is the earliest and most reliable clinical sign of acute compartment syndrome in a conscious patient?

  1. Pallor of the overlying skin
  2. Absent distal arterial pulse
  3. Flaccid paralysis of the limb
  4. Pain on passive stretch Correct answer.

Explanation

Pain out of proportion to the injury and pain with passive stretch of the compartment muscles are the earliest and most sensitive findings. Distal pulses often remain palpable until late in the process.

Question 3General Orthopedics and Osteopathic Principles

Which statement best defines an osteopathic somatic dysfunction?

  1. Inflammatory arthritis of a synovial joint
  2. Fracture through a growth plate
  3. Bacterial infection of muscle and fascia
  4. Altered function of somatic tissues Correct answer.

Explanation

Somatic dysfunction is impaired or altered function of skeletal, arthrodial, myofascial, and related vascular, lymphatic, and neural components. It is identified by tenderness, asymmetry, restricted motion, and tissue texture change rather than by infection or fracture alone.

Question 4General Orthopedics and Osteopathic Principles

A bone mineral density T-score at or below which value establishes osteoporosis in a postmenopausal woman?

  1. -2.5 Correct answer.
  2. -1.5
  3. -2.0
  4. -1.0

Explanation

The World Health Organization defines osteoporosis as a T-score of -2.5 or lower at the hip or spine. T-scores between -1.0 and -2.5 indicate osteopenia, and a score of -1.0 or higher is normal.

Question 5General Orthopedics and Osteopathic Principles

Which study is most important for confirming septic arthritis of a native knee?

  1. Magnetic resonance imaging
  2. Serum uric acid measurement
  3. Standing radiograph of the knee
  4. Joint aspiration with culture and cell count Correct answer.

Explanation

Synovial fluid analysis with cell count, Gram stain, and culture is the definitive test for septic arthritis. Radiographs and MRI may support the evaluation but cannot confirm the diagnosis.

Question 6General Orthopedics and Osteopathic Principles

Which physical examination test is most sensitive for an anterior cruciate ligament tear?

  1. McMurray test
  2. Thompson test
  3. Apprehension test
  4. Lachman test Correct answer.

Explanation

The Lachman test assesses anterior tibial translation with the knee slightly flexed and is the most sensitive examination for an ACL tear. The McMurray test assesses meniscal tears, the Thompson test assesses the Achilles tendon, and the apprehension test assesses patellar instability.

Question 7General Orthopedics and Osteopathic Principles

Which radiographic feature is most characteristic of osteoarthritis?

  1. Asymmetric narrowing with osteophytes Correct answer.
  2. Chondrocalcinosis alone
  3. Marginal erosions with periarticular osteopenia
  4. Uniform joint space widening

Explanation

Osteoarthritis classically produces asymmetric joint space narrowing, osteophytes, subchondral sclerosis, and subchondral cysts. Marginal erosions and periarticular osteopenia are more typical of rheumatoid arthritis.

Question 8General Orthopedics and Osteopathic Principles

Which synovial fluid crystal is diagnostic of gout?

  1. Birefringent cholesterol crystals
  2. Amorphous calcium phosphate aggregates
  3. Needle-shaped negatively birefringent urate crystals Correct answer.
  4. Rhomboid-shaped, positively birefringent calcium pyrophosphate crystals

Explanation

Gout is caused by monosodium urate crystals, which are needle-shaped and negatively birefringent under polarized light. Calcium pyrophosphate crystals in pseudogout are rhomboid-shaped and positively birefringent.

Question 9General Orthopedics and Osteopathic Principles

A 9-year-old falls and has tenderness over the distal radius physis. Radiographs show a fracture line through the physis and a small triangular metaphyseal fragment. Which Salter-Harris type is this?

  1. Type I
  2. Type II Correct answer.
  3. Type IV
  4. Type III

Explanation

A Salter-Harris type II fracture passes through the physis and exits through the metaphysis, creating a metaphyseal corner fragment. It is the most common type and generally has a good prognosis.

Question 10General Orthopedics and Osteopathic Principles

According to Fryette's first law of spinal mechanics, in a neutral spine sidebending and rotation occur in which relationship?

  1. Same direction, with sidebending preceding rotation
  2. Independently, with no coupling
  3. Opposite directions Correct answer.
  4. Same direction, with rotation preceding sidebending

Explanation

Fryette's first law applies to a neutral spine and describes sidebending and rotation occurring in opposite directions. Fryette's second law applies to a non-neutral spine and describes same-direction coupling.

Question 11General Orthopedics and Osteopathic Principles

Which timing and clinical picture best fit fat embolism syndrome after a femoral shaft fracture?

  1. Several weeks later with hepatic failure
  2. Within minutes with unilateral leg swelling
  3. Immediately at injury with isolated bradycardia
  4. 24 to 72 hours later with hypoxemia and petechiae Correct answer.

Explanation

Fat embolism syndrome typically appears 24 to 72 hours after a long bone fracture with hypoxemia, neurologic changes, and a petechial rash. The diagnosis is clinical and supportive care is the main treatment.

Question 12General Orthopedics and Osteopathic Principles

A patient has a midshaft humeral fracture and cannot extend the wrist or fingers. Which nerve is most likely injured?

  1. Median nerve
  2. Musculocutaneous nerve
  3. Ulnar nerve
  4. Radial nerve Correct answer.

Explanation

The radial nerve runs in the spiral groove of the humerus and is vulnerable in midshaft fractures. Injury causes wrist drop and weakness of finger extension.

Question 13General Orthopedics and Osteopathic Principles

A patient has a closed tibial shaft fracture. Which factor most strongly increases the risk of compartment syndrome?

  1. High-energy injury with marked swelling Correct answer.
  2. Application of a well-padded splint
  3. A transverse fracture with minimal displacement
  4. Isolated fracture of the fibula

Explanation

High-energy injuries with extensive soft tissue swelling, crushing, or tight casts increase compartment pressure and the risk of compartment syndrome. Minimally displaced fractures and well-padded splints are lower-risk situations.

Question 14General Orthopedics and Osteopathic Principles

A child with sickle cell disease develops osteomyelitis. Which organism should be specifically considered in addition to Staphylococcus aureus?

  1. Clostridium perfringens
  2. Pseudomonas aeruginosa
  3. Salmonella species Correct answer.
  4. Neisseria gonorrhoeae

Explanation

Salmonella species are classically associated with osteomyelitis in sickle cell disease, although Staphylococcus aureus remains a common cause. Bowel ischemia and impaired clearance are thought to contribute to Salmonella risk.

Question 15General Orthopedics and Osteopathic Principles

Which pharmacologic agent is a standard option for venous thromboembolism prophylaxis after elective total hip arthroplasty?

  1. Aspirin at analgesic dose only
  2. Oral vitamin K antagonist started on postoperative day 1 without monitoring
  3. Intravenous unfractionated heparin at treatment dose
  4. Low-molecular-weight heparin at prophylactic dose Correct answer.

Explanation

Prophylactic-dose low-molecular-weight heparin is a standard option after total hip arthroplasty, along with other guideline-endorsed agents such as fondaparinux or aspirin in selected patients. Treatment-dose anticoagulation is reserved for established thrombosis.

Question 16General Orthopedics and Osteopathic Principles

Which fracture is most classically associated with Volkmann ischemic contracture?

  1. Lateral condyle fracture of the elbow
  2. Olecranon fracture
  3. Supracondylar fracture of the humerus Correct answer.
  4. Radial head fracture

Explanation

Supracondylar humeral fractures can injure or compress the brachial artery and raise pressure in the volar forearm compartment. Untreated ischemia leads to Volkmann contracture with forearm muscle fibrosis and deformity.

Question 17General Orthopedics and Osteopathic Principles

In muscle energy technique, what does the patient do?

  1. Actively contract a muscle against physician counterforce Correct answer.
  2. Breathe rapidly while the physician performs a lymphatic pump
  3. Hold a tender point in a position of strain for 90 seconds
  4. Passively relax while the physician applies a high-velocity thrust

Explanation

Muscle energy technique uses the patient's voluntary muscle contraction against a counterforce provided by the physician. This is followed by relaxation and movement into the restrictive barrier.

Question 18General Orthopedics and Osteopathic Principles

Which description best characterizes counterstrain technique?

  1. Positioning the patient in comfort to reduce a tender point Correct answer.
  2. A high-velocity low-amplitude thrust into the restrictive barrier
  3. Sustained traction applied to the cervical spine
  4. Rhythmic springing of a joint through its full range

Explanation

Counterstrain places the patient in a position of comfort that reduces tension at a tender point, often for about 90 seconds. It is an indirect technique rather than a thrust or springing technique.

Question 19General Orthopedics and Osteopathic Principles

A patient has a posterior hip dislocation after a dashboard injury. Which leg posture is expected on the affected side?

  1. Shortened and externally rotated
  2. Shortened and internally rotated Correct answer.
  3. Lengthened and externally rotated
  4. Lengthened and internally rotated

Explanation

Posterior hip dislocation typically produces a shortened, adducted, and internally rotated leg. Anterior dislocation more often produces a shortened and externally rotated leg.

Question 20General Orthopedics and Osteopathic Principles

Which medication class is most strongly associated with secondary osteoporosis?

  1. Beta-blockers
  2. Thiazide diuretics
  3. Proton pump inhibitors at low dose
  4. Systemic glucocorticoids Correct answer.

Explanation

Systemic glucocorticoids reduce bone formation, impair calcium balance, and are a leading cause of secondary osteoporosis. Thiazide diuretics tend to reduce urinary calcium loss rather than cause bone loss.

Question 21General Orthopedics and Osteopathic Principles

Which finding defines a Gustilo-Anderson type IIIC open fracture?

  1. Arterial injury requiring repair, regardless of soft tissue damage Correct answer.
  2. A wound caused by a farm implement with fecal contamination
  3. Extensive soft tissue loss with periosteal stripping and bone exposure
  4. A wound larger than 1 cm without extensive soft tissue injury

Explanation

Gustilo-Anderson type IIIC is defined by an open fracture with an arterial injury that requires repair, independent of the soft tissue wound severity. Type IIIB requires soft tissue coverage because of periosteal stripping and bone exposure.

Question 22General Orthopedics and Osteopathic Principles

Which site is most typical for conventional osteosarcoma?

  1. Metaphysis of the distal femur Correct answer.
  2. Diaphysis of the ulna
  3. Posterior elements of a vertebral body
  4. Epiphysis of the proximal tibia

Explanation

Conventional osteosarcoma most often arises in the metaphysis of long bones around the knee, especially the distal femur and proximal tibia. It typically affects adolescents and young adults.

Question 23General Orthopedics and Osteopathic Principles

In the osteopathic cranial concept, the cranial rhythmic impulse is generally described as having what rate?

  1. 6 to 12 cycles per minute Correct answer.
  2. 2 to 4 cycles per minute
  3. 20 to 30 cycles per minute
  4. 40 to 60 cycles per minute

Explanation

The cranial rhythmic impulse is traditionally described as a palpable rhythm of about 6 to 12 cycles per minute. It is distinct from the faster arterial pulse and the respiratory rate.

Question 24General Orthopedics and Osteopathic Principles

Which intracompartmental pressure difference is generally used as a threshold for fasciotomy in acute compartment syndrome?

  1. Difference of 30 mmHg or less Correct answer.
  2. Difference of 40 mmHg or more
  3. Difference of 50 mmHg or more
  4. Absolute pressure greater than 10 mmHg

Explanation

The delta pressure is the diastolic blood pressure minus the compartment pressure, and a value of 30 mmHg or less is generally an indication for fasciotomy. This difference is more reliable than an absolute pressure alone.

Question 25General Orthopedics and Osteopathic Principles

Which statement best distinguishes a myofascial trigger point from a tender point?

  1. Both are identical and differ only in location
  2. Trigger points refer pain and twitch; tender points are locally painful Correct answer.
  3. A tender point produces referred pain, whereas a trigger point is painless
  4. A trigger point is always associated with radiculopathy

Explanation

Myofascial trigger points produce local and referred pain and may show a local twitch response. Tender points are locally painful but do not refer pain in the same pattern.

Question 26Orthopedic Trauma and Fracture Care

A 9-year-old falls on an outstretched hand and has tenderness over the distal radius physis. Radiographs show a fracture line through the physis that extends through the metaphysis. Which Salter-Harris type is this?

  1. Type III
  2. Type I
  3. Type IV
  4. Type II Correct answer.

Explanation

Salter-Harris type II fractures pass through the physis and exit through the metaphysis, producing a Thurston-Holland fragment. Type I involves only the physis, type III involves the physis and epiphysis, and type IV crosses the metaphysis, physis, and epiphysis. Type II is the most common Salter-Harris injury.

Question 27Orthopedic Trauma and Fracture Care

A 65-year-old woman falls on an outstretched hand and has a distal radius fracture with dorsal displacement and dorsal angulation. Which eponym describes this fracture?

  1. Smith fracture
  2. Chauffeur fracture
  3. Barton fracture
  4. Colles fracture Correct answer.

Explanation

A Colles fracture is a distal radius fracture with dorsal displacement and dorsal angulation, often with radial shortening. Smith fractures have volar displacement, Barton fractures involve an intra-articular rim, and chauffeur fractures involve the radial styloid.

Question 28Orthopedic Trauma and Fracture Care

Which carpal bone is most commonly fractured and carries a high risk of avascular necrosis of its proximal pole?

  1. Triquetrum
  2. Scaphoid Correct answer.
  3. Lunate
  4. Pisiform

Explanation

The scaphoid is the most commonly fractured carpal bone, and its retrograde blood supply makes the proximal pole vulnerable to avascular necrosis. Tenderness in the anatomic snuffbox should prompt immobilization and repeat imaging if initial radiographs are negative.

Question 29Orthopedic Trauma and Fracture Care

Which portion of the clavicle is most frequently fractured?

  1. Lateral third
  2. Middle third Correct answer.
  3. Medial third
  4. Intra-articular end

Explanation

The middle third of the clavicle is the most common fracture site because it is the thinnest and weakest part of the bone. Medial and lateral third fractures are less common and have different associated injury concerns.

Question 30Orthopedic Trauma and Fracture Care

A young man has an anterior shoulder dislocation. Which nerve is most at risk of injury?

  1. Axillary nerve Correct answer.
  2. Radial nerve
  3. Musculocutaneous nerve
  4. Median nerve

Explanation

The axillary nerve runs close to the surgical neck of the humerus and is the nerve most commonly injured with anterior shoulder dislocation. Deltoid weakness and reduced sensation over the lateral shoulder should be checked before and after reduction.

Question 31Orthopedic Trauma and Fracture Care

Which clinical triad suggests fat embolism syndrome after a long bone fracture?

  1. Oliguria, hypertension, and a diffuse rash
  2. Fever, bradycardia, and jaundice
  3. Hypoxemia, petechiae, and confusion Correct answer.
  4. Bradycardia, hypothermia, and ileus

Explanation

Fat embolism syndrome classically causes respiratory distress, a petechial rash, and neurologic changes, usually 24 to 72 hours after long bone or pelvic trauma. Hypoxemia is often the earliest finding, and supportive care is the main treatment.

Question 32Orthopedic Trauma and Fracture Care

Which organism is the most common cause of post-traumatic osteomyelitis after an open fracture?

  1. Staphylococcus aureus Correct answer.
  2. Neisseria meningitidis
  3. Pseudomonas aeruginosa
  4. Clostridium perfringens

Explanation

Staphylococcus aureus is the most common pathogen in post-traumatic and postoperative osteomyelitis. Open fracture wounds can also be contaminated with gram-negative organisms, so cultures guide antibiotic therapy.

Question 33Orthopedic Trauma and Fracture Care

In a nonsurgically treated long bone fracture, which process characterizes secondary fracture healing?

  1. Cartilage formation without inflammation
  2. Direct osteonal remodeling without callus
  3. Callus formation via endochondral ossification Correct answer.
  4. Primary bone union across compressed fracture ends

Explanation

Secondary healing involves hematoma, inflammation, soft callus, hard callus, and remodeling, with callus formed through endochondral ossification. Primary healing occurs with rigid compression and direct osteonal remodeling without visible callus.

Question 34Orthopedic Trauma and Fracture Care

An open tibial fracture has extensive soft tissue loss with periosteal stripping and exposed bone, but no arterial injury requiring repair. What Gustilo-Anderson grade is this?

  1. II
  2. IIIA
  3. IIIC with arterial repair
  4. IIIB Correct answer.

Explanation

Gustilo-Anderson type IIIB describes extensive soft tissue loss with periosteal stripping and exposed bone that requires flap coverage. Type IIIA has adequate soft tissue coverage, and type IIIC requires arterial repair.

Question 35Orthopedic Trauma and Fracture Care

Which finding is the most reliable early clinical indicator of acute compartment syndrome in a conscious patient?

  1. Absent distal pulse
  2. Paralysis of the muscles within the affected compartment
  3. Pain on passive stretch of the compartment muscles Correct answer.
  4. Pallor of the overlying skin

Explanation

Pain out of proportion to the injury and pain on passive stretch are the earliest and most reliable clinical signs of compartment syndrome. Pulselessness, pallor, and paralysis are late findings and should not be awaited.

Question 36Orthopedic Trauma and Fracture Care

Which artery is most important for blood supply to the femoral head and is at risk in displaced femoral neck fractures?

  1. Superior gluteal artery from the internal iliac
  2. Obturator artery
  3. Inferior epigastric artery
  4. Medial circumflex femoral artery Correct answer.

Explanation

The medial circumflex femoral artery gives rise to the lateral epiphyseal branches that supply most of the femoral head. Displaced femoral neck fractures can disrupt these branches and lead to avascular necrosis.

Question 37Orthopedic Trauma and Fracture Care

A child has an extension-type supracondylar humeral fracture. Which radiographic line helps assess for posterior displacement on the lateral view?

  1. Böhler line
  2. Shenton line
  3. Radiocapitellar line
  4. Anterior humeral line Correct answer.

Explanation

The anterior humeral line should intersect the middle third of the capitellum on a true lateral radiograph. In extension-type supracondylar fractures, the line passes anterior to the capitellum because the distal fragment is displaced posteriorly.

Question 38Orthopedic Trauma and Fracture Care

A distal fibula fracture at the level of the ankle joint, with no syndesmotic widening on stress testing, corresponds to which Danis-Weber type?

  1. Weber A
  2. Weber B Correct answer.
  3. Weber C with syndesmotic disruption
  4. Weber D

Explanation

Danis-Weber type B fractures occur at the level of the syndesmosis and may be stable or unstable depending on the injury pattern. Type A is below the joint, and type C is above the joint with a higher risk of syndesmotic disruption.

Question 39Orthopedic Trauma and Fracture Care

A fracture of the proximal ulnar shaft with dislocation of the radial head is known as which injury?

  1. Essex-Lopresti injury
  2. Galeazzi fracture-dislocation of the forearm
  3. Nightstick fracture
  4. Monteggia fracture-dislocation Correct answer.

Explanation

A Monteggia fracture-dislocation combines a proximal ulnar shaft fracture with radial head dislocation. A Galeazzi injury is a distal radius fracture with distal radioulnar joint disruption.

Question 40Orthopedic Trauma and Fracture Care

A distal radius fracture with disruption of the distal radioulnar joint is best described as which injury?

  1. Smith fracture
  2. Galeazzi fracture-dislocation Correct answer.
  3. Barton fracture with volar rim involvement
  4. Colles fracture

Explanation

A Galeazzi fracture-dislocation is a distal radius fracture with distal radioulnar joint disruption. Colles and Smith fractures describe displacement direction, and Barton fractures involve an intra-articular rim.

Question 41Orthopedic Trauma and Fracture Care

A patient in a motor vehicle crash presents with the hip flexed, adducted, and internally rotated. What is the most likely diagnosis?

  1. Anterior hip dislocation
  2. Posterior hip dislocation Correct answer.
  3. Femoral neck fracture
  4. Acetabular fracture without dislocation

Explanation

Posterior hip dislocation classically presents with the hip flexed, adducted, and internally rotated, often after a dashboard injury. The sciatic nerve and posterior wall of the acetabulum are at risk.

Question 42Orthopedic Trauma and Fracture Care

A patient falls from height and has heel pain. Which finding is most characteristic of an intra-articular calcaneal fracture?

  1. Increased anterior drawer sign
  2. Positive McMurray test
  3. Decreased Böhler angle Correct answer.
  4. Positive Finkelstein test

Explanation

A decreased Böhler angle indicates loss of calcaneal height and is characteristic of intra-articular calcaneal fractures. These injuries warrant assessment of the lumbar spine because axial loading can cause concomitant fractures.

Question 43Orthopedic Trauma and Fracture Care

A patient has a dirty open fracture and an unknown tetanus immunization history. What is the appropriate tetanus prophylaxis?

  1. No prophylaxis if the wound is adequately irrigated
  2. Tetanus immune globulin alone
  3. Tetanus toxoid alone
  4. Toxoid plus immune globulin Correct answer.

Explanation

For a dirty or severe wound with unknown or incomplete tetanus immunization, both tetanus toxoid and tetanus immune globulin are indicated. Wound irrigation alone does not replace immunization.

Question 44Orthopedic Trauma and Fracture Care

In open fracture management, which measure most directly reduces the risk of infection and should be given as early as possible?

  1. Delayed wound closure at 72 hours
  2. Routine intra-articular steroid injection
  3. Immediate bone grafting
  4. Intravenous antibiotics Correct answer.

Explanation

Early intravenous antibiotics are a key intervention for reducing infection after open fractures and should be administered promptly, along with tetanus prophylaxis and surgical debridement. The choice of antibiotic depends on the wound grade and contamination.

Question 45Orthopedic Trauma and Fracture Care

Which definition best describes a fracture nonunion?

  1. Healing with malalignment greater than 5 degrees
  2. Delayed healing that resolves with cast change
  3. No healing by 6 to 9 months without imaging progression Correct answer.
  4. Failure of healing by 6 weeks with callus visible on radiographs

Explanation

Nonunion is generally defined as failure to heal by 6 to 9 months with no progressive signs of healing on serial imaging. It may be hypertrophic or atrophic and often requires surgical intervention.

Question 46Orthopedic Trauma and Fracture Care

Which intracompartmental pressure finding is an indication for urgent fasciotomy in a patient with suspected compartment syndrome?

  1. Absolute pressure of 15 mmHg
  2. Absolute pressure of 20 mmHg with normal exam
  3. Delta pressure less than 30 mmHg Correct answer.
  4. Delta pressure greater than 40 mmHg

Explanation

The delta pressure is the diastolic blood pressure minus the compartment pressure; a value less than 30 mmHg suggests inadequate perfusion and supports fasciotomy. An absolute compartment pressure above 30 to 40 mmHg is also concerning.

Question 47Orthopedic Trauma and Fracture Care

A 3-year-old child has an isolated closed midshaft femoral fracture. Which treatment is most appropriate?

  1. Open reduction and plate fixation
  2. Above-knee amputation
  3. Immediate intramedullary nailing through the greater trochanter
  4. Early spica cast or traction followed by spica cast Correct answer.

Explanation

Young children with isolated femoral shaft fractures are typically treated with early spica casting or a period of traction followed by casting. Flexible intramedullary nails are more common in older children, and rigid trochanteric nailing risks avascular necrosis in young patients.

Question 48Orthopedic Trauma and Fracture Care

A radial head fracture has a single fragment displaced more than 2 mm but no comminution. Which Mason classification is this?

  1. Mason III
  2. Mason II Correct answer.
  3. Mason I
  4. Mason IV

Explanation

Mason II describes a partial articular radial head fracture with displacement, often more than 2 mm. Mason I is nondisplaced, Mason III is comminuted, and Mason IV includes elbow dislocation.

Question 49Orthopedic Trauma and Fracture Care

A pelvic radiograph shows symphysis pubis diastasis of 3 cm with widening of the sacroiliac joints. What is the most appropriate initial management priority?

  1. Closed reduction and cast immobilization
  2. Hemodynamic stabilization and pelvic binder Correct answer.
  3. Immediate hip spica cast
  4. Observation with serial radiographs and repeat hemoglobin checks

Explanation

This is an unstable open-book pelvic injury with a high risk of hemorrhage. Initial management prioritizes hemodynamic resuscitation and pelvic stabilization with a binder or external fixator before definitive fixation.

Question 50Orthopedic Trauma and Fracture Care

Which organism is most commonly responsible for gas gangrene after a contaminated open fracture?

  1. Streptococcus pneumoniae
  2. Clostridium perfringens Correct answer.
  3. Staphylococcus epidermidis
  4. Escherichia coli

Explanation

Clostridium perfringens is a gram-positive anaerobic bacillus that causes gas gangrene through tissue toxins and gas production. Treatment requires urgent debridement and antibiotics such as penicillin.