Question 1

Following open reduction and internal fixation of ankle fractures, early mobilization in a removable cast demonstrated:

Explanation

Patients treated with early mobilization in a removable custom fiberglass orthosis (non-weight bearing) had higher early functional scores, earlier return to work, but a higher rate of postoperative wound infection. There were no differences between the two groups with regard to the quality of life at 6 months or the costs of physical therapy.

Question 2

In comparing the clinical efficacy of intra-articular sodium hyaluronate injections vs triamcinolone injections for the treatment of hallux rigidus, which factor showed significantly better improvement in the sodium hyaluronate group:

Explanation

In a prospective randomized study comparing sodium hyaluronate vs cortisone injections for hallux rigidus, gait pain and AOFAS scores were significantly better in the sodium hyaluronate-treated group. There was no significant difference between the two treatment groups with regard to rest pain, pain with mobilization, pain with palpation, and use of analgesics.

Question 3

Which anatomical feature does not predispose patients to peroneal tendon dislocation:

Explanation

A varus heel alignment would stabilize the peroneal tendons medially into the peroneal groove. Valgus heel alignment is associated with increased risk for peroneal tendon dislocation because this predisposes the tendons to move laterally out of the groove. The other anatomical features have all been implicated as risk factors for peroneal tendon dislocation.

Question 4

A 39-year-old man has a forced dorsiflexion injury while skiing. Radiographs taken in the emergency department show a small avulsion flake off the lateral surface of the fibula distally on the mortise view. This patient most likely has:

Explanation

A forced dorsiflexion injury, especially with skiing, is a common mechanism described for peroneal tendon dislocation. All of the diagnoses listed are potential injuries that can initially be mistaken for an ankle sprain. The flake avulsion off of the lateral border of the distal fibula is almost pathognomonic of a peroneal tendon dislocation injury.

Question 5

Which of the following is not considered to be a risk factor for peroneal tendon tears:

Explanation

A shallow retrofibular groove and ligamentous laxity predispose to subluxation of the peroneal tendons causing attritional tears over the posterolateral fibular ridge. Varus hindfoot alignment places patients at risk for inversion sprains, which may cause trauma to the peroneal tendons when they are put on stretch. Heel chord contracture has not been implicated in the development of peroneal tendon tears.

Question 6

The thoracic outlet syndrome is characterized by:

Explanation

The thoracic outlet syndrome is a compressive neurovascular disorder of the upper extremity with many possible sites of entrapment. Abnormal congenital structures, macro-, and micro-trauma have all been implicated as possible mechanisms for the process, though none of these factors is an absolute requisite for the disorder. Neurologic symptoms are more common than vascular complaints. The subclavian vein passes anterior to the interscalene interval which contains the subclavian artery and the brachial plexus.C orrect Answer: Proximal compression of upper extremity neurologic and vascular structures at one of multiple

Question 7

A typical presentation of thoracic outlet syndrome is likely to include:

Explanation

A lower plexus symptom constellation involving muscles supplied by the ulnar nerve is most typical of thoracic outlet syndrome. Objective signs of sensory loss and diminished strength are often not found. Somatosensory evoked potential abnormalities are common (74%), but are non-specific and may be seen in asymptomatic individuals. Although venous obstruction is rare, it may lead to subclavian or axillary vein thrombosis necessitating fibrinolytic treatment. Symptoms are usually exacerbated by upper extremity activities.

Question 8

Primary treatment of thoracic outlet syndrome should include:

Explanation

Initial treatment of thoracic outlet syndrome is non-operative. Aggravating activities are modified and shoulder girdle strengthening is initiated. Surgery is considered for patients who have failed conservative therapy and suffer intractable pain, and for those who have significant neurologic or vascular deficits. Operative procedures must be tailored to the presumed pathological anatomy; there is no single best procedure.

Question 9

The term acrosyndactyly describes digits that are:

Explanation

Acrosyndactyly describes digits that are joined distally but remain separated by a proximal cleft. Acrosyndactylized digits initially develop normal web spaces, but are subsequently joined by secondary events, such as the formation of constriction bands. In contrast to syndactylized fingers, which remain joined due to failure of formation of the web space between contiguous digits, acrosyndactyly may form between non-contiguous digits. C omplex syndactyly involves a confluence of distal osseous and nail elements in addition to soft-tissue bridging. Simple syndactyly describes digits that are joined by soft tissue only. Finally, complete syndactyly refers to digits that are joined along their entire lengths, while incomplete syndactyly describes a web that extends more distally than usual, but not all the way to the finger tips.

Question 10

In normal development, the differentiation of the interdigital web space is influenced by which of the following factors:

Explanation

The distal phalanges are composed of two germ cell layers. Ectodermal cells produce the tuft of the distal phalanx and the nail elements, while mesodermal cells form the epiphysis, physis, and metaphysis. Apical ectodermal ridge maintenance factor (AERMF) is a substance elaborated by the mesenchymal condensations between digits. When AERMF ceases to be produced, the apical ectodermal ridge begins to break apart. This in turn triggers the release of lysosomes which dissolve the mesenchymal connections between the developing digits, completing web space formation.

Question 11

Syndactyly may be isolated, it may be bilateral, or it may occur as part of a broader genetic syndrome. Which of the following syndromes are commonly associated with syndactyly:

Explanation

Individuals afflected by Polandâ s anomaly exhibit unilateral symbrachydactyly (simple syndactyly with short or absent middle phalanges), absent sternocostal head of the pectoralis major, and hypoplasia of the ipsilateral breast and nipple. Apertâ s syndrome, the other syndrome most commonly associated with syndactyly, is characterized by complex acrosyndactyly of the hands and feet associated with premature closure of the cranial sutures. The features of the VATER association include Verterbral anomalies and or Ventricular septal defect, Anal atresia, T-E fistula, and Renal anomalies and or Radial dysplasia (pre-axial syndactyly is a possible but inconsistent feature). Individuals with Marfan syndrome exhibit arachnodactyly in addition to retinal detachments, lens subluxations, aortic dilatations/aneurysms, and tall stature with long, thin limbs. Hand manifestations of Down syndrome include short metacarpals and phalanges, clinodactyly, and abnormal crease patterns, but not syndactyly. Hunter syndrome (mucopolysaccharidosis II) is marked by stiffened joints and the development of a clawhand, but not by syndactyly.

Question 12

Surgical separation of syndactylized fingers produces two separate digits with an increase in total surface area. How are the gaps in coverage left by eliminating the common side between the two fingers best addressed:

Explanation

If syndactyly release is to be successful, contractures must be avoided at all costs. Tension-free closures are imperative to this effort. The surface area of two complete fingers is substantially greater than that of two fingers that share a common side, so primary closure of the skin on both sides of the new web is not possible without tension except in very proximal, incomplete syndactylies. For this reason, a strategy other than primary closure is necessary. Healing by secondary intention and splitthickness grafting are both prone to produce contracture. Fascio-cutaneous grafting and rotation flaps are unnecessary, since the defect is confined to the dermal layer. Full- thickness skin graft is least likely to contract, and thus is the material of choice for closing the separated digits.

Question 13

The ______ of the brachial plexus emerge between the anterior middle scalane muscles:

Explanation

After the roots emerge between the anterior scalene muscles, they merge to form trunks. The trunks branch into divisions and then merge into cords in the axilla. The cords branch into nerves.

Question 14

Dupuytren contracture is a progressive disease involving:

Explanation

Dupuytren contracture involves proliferative fibrodysplasia of the subcutaneous palmar connective tissue. The flexor tendons are not involved. Pretendinous bands of the palmer aponeurosis form nodules and cords causing metacarpophalangeal joint contracture. The interphalangeal joint can be affected but only rarely is the distal interphalangeal joint involved. There is no inflammatory response but a proliferation of myofibroblasts with an increase in Type 3 collagen. The disease is most often seen in men between the ages of 40 and 60 years old and is associated with epilespy, alcoholism and diabetes. C arpal tunnel syndrome is often seen in young women and can be exacerbated by pregnancy.

Question 15

Which of the following statements is true:

Explanation

Electromyography/nerve conduction velocity is usually normal in pronator syndrome, but abnormal in anterior interosseous nerve syndrome. The arcade of Struthers describes a possible point of compression of the ulnar nerve. The ligament of Struthers describes a possible point of compression of the median nerve. In AIN syndrome, forearm pronation may be weak due to weakness of the pronator quadratus, but the pronator teres is unaffected. There is no strict correlation between the pain of pronator syndrome and sleeplessness.

Question 16

Initial treatment for De Quervain disease involves:

Explanation

Initial treatment for De Quervain tenosynovitis involves rest and splinting with steroid injection into the first dorsal compartment. The splint should be worn as much as possible for 3 to 4 weeks. The extensor carpi radialis brevis has been implicated in lateral epicondulitis. The extensor pollicis longus can be a source of pain as it wraps over the wrist extensor giving the classic symptoms of intersection syndrome between the second and third dorsal compartments. Surgical release is only indicated in persistent cases that have failed conservative management. In 20% to 30% of cases, the first compartment is divided by longitudinal septations into two distinct tunnels. Care must be taken to identify and release both of these tunnels, as well as any multiple tendinous slips, when performing a surgical release.

Question 17

The ulnar nerve arises from:

Explanation

The ulnar nerve is the continuation of the medial cord of the brachial plexus containing fibers of the C 8 and T1 nerve roots. Radiculopathy at the C 8-T1 level may mimic a more distal compression of the nerve in the cubital tunnel. The axillary and radial nerves come off the posterior cord. There is no lateral trunk of the brachial plexus. The nerve to the rhomboids comes directly off of the C 5 nerve root and its presence is often helpful in differentiating pre-ganglionic from post-ganglionic lesions of the brachial plexus. The lateral cord forms the musculocutaneous nerve. The medial cord forms the ulnar nerve. The medial and lateral cords form the median nerve. The radial nerve arises from the posterior cord.

Question 18

Which of the following statements is true:

Explanation

The PIN contains motor fibers to the EDC , EDQP, EC U, APL, EPB, EPL, and EIP. Occasionally it gives motor fibers to the EC RB. It terminates with a sensory branch to the carpus and wrist capsule. There is, however, no cutaneous sensation. In radial tunnel syndrome, the entire radial nerve is compressed, including a sensory component. The radial nerve passes posteriorly and laterally next to the humerus, but not with the radial artery. Wartenberg's sign is an isolated ulnar nerve palsy. This syndrome relates to the compression of the superficial branch of the radial nerve. The most common site of radial nerve compression is the arcade of Frohse.

Question 19

The treatment of stenosing tenosynovitis should include all of the following except:

Explanation

The A2 pulley should not be released as part of the treatment for trigger finger. Its presence, along with the A4 pulley, is important in maintaining efficient flexor tendon function. The pathology usually involves the A1 pulley and its release is usually all that is necessary. Other modalities include NSAIDs, splinting, tenosynovectomy, and steroid injections.

Question 20

Swan-neck deformity can be caused by which of the following:

Explanation

A chronic mallet finger results in proximal retraction of the extensor mechanism and overpull of the central slip. Isolated central slip rupture does not cause this deformity. Rupture of the flexor digitorum sublimis can cause Swan-neck deformity. MP arthroplasty is not associated with this deformity. The sequalae of dorsal proximal interphalangeal joint dislocation (e.g., volar plate laxity or deficiency) leads to Swan-neck deformity.

Question 21

Which of the following identifies the clinical finding of inadvertent hyperextension of the thumb metaphalangeal joint during attempted thumb- index finger pinch?

Explanation

Jeanne's sign identifies thumb metaphalangeal joint hyperextension of 10Â° to 15° with key pinch or gross grip. Froment's sign refers to the exaggeration of thumb interphalangeal joint flexion during key punch by the flexor pollicis longus in ulnar nerve palsies. Wartenberg's sign is the inability to adduct the extended small finger due to an ulnar nerve palsy. Duchenne's sign refers to clawing of the ring and small fingers. Pollock's sign is the inability to flex the distal interphalangeal joints of the ring and small fingers in high palsies.

Question 22

The Bunnell procedure to provide index finger abduction in ulnar nerve palsies refers to:

Explanation

The Bunnell procedure transfers the EIP to the first dorsal interosseous. Answers B through E refer to the Omer technique, Bruner technique, Abreu technique, and Graham procedure or Riordan procedure, respectively.

Question 23

Ganglions most commonly arise from the:

Explanation

Sixty percent to 70% of all ganglion cysts occur on the dorsum of the wrist. A majority of ganglions emanate from the scapholunate interosseous ligament. Volar wrist ganglions are prevalent in 16% to 20% of cases, followed by volar retinacular ganglions occurring at the metacarpophalangeal joints and proximal interphalangeal joints (7% to 12%), and mucous cysts presenting dorsally at the level of the joint.

Question 24

Pain from a dorsal carpal ganglion is caused by:

Explanation

Dorsal carpal ganglions arising from the scapholunate interosseous ligament may expand to a large size without causing significant pain. Alternatively, small ganglions that compress the sensory terminus of the posterior interosseous nerve may be painful. The median nerve, on the volar side of the wrist, is not affected by dorsal ganglions. Dorsal carpal ganglions are benign. They have no potential for malignant degeneration and are not a significant cause of tendinitis.

Question 25

Optimal treatment for a symptomatic ganglion is:

Explanation

Surgical excision of a symptomatic ganglion, with removal of the entire ganglion stalk and a portion of the joint capsule at its base, reliably relieves pain and has a low recurrence rate (approximately 5%). C losed rupture, while potentially effective, has a recurrence rate of approximately 50%. Ganglions are prone to recur after aspiration, although 3 serial aspirations of a ganglion have been shown to reduce the recurrence rate to about 15%. The addition of corticosteroids to aspiration treatment has not been shown to provide any additional benefit. While observation of painless ganglions is certainly acceptable treatment given their benign prognosis, it is not considered the optimal course for a symptomatic lesion.

Question 26

The following pair of tendons is affected in De Quervain disease:

Explanation

De Quervain disease affects the tendons in the first dorsal compartment, the extensor pollicis brevis and the abductor pollicis longus (consisting of 2 to 7 individual tendon slips). The extensor pollicis longus traverses the third dorsal compartment. The abductor pollicis brevis and the opponens pollicis are thenar muscles and do not lie within any of the dorsal compartments.

Question 27

Poor or incomplete resolution of symptoms following first dorsal compartment release for De Quervain disease would most likely occur as a result of:

Explanation

The most common reason for recurrent or persistent symptoms of first dorsal compartment stenosis is failure to recognize and release a separate extensor pollicis brevis subsheath. The superficial radial sensory nerve may be injured in surgery for De Quervain disease, but the resulting neuroma is often more painful than the original symptoms and is of a different character. Abductor pollicis longus laceration would result in loss of radial abduction of the thumb. Early motion of the thumb is recommended following release of the first dorsal compartment.

Question 28

When performing a tendon transfer to restore thumb index finger lateral pinch in an ulnar nerve palsy, which tendon, when transferred to the 1st dorsal interosseous provides the greatest power?

Explanation

The EC RB transfer gives the greatest return of power pinch due to the strength of this wrist motor. This transfer should be coupled with a thumb MP arthrodesis to provide the best results. The ideal pinch transfer is an extensor pollicis brevis to first dorsal interosseous with a metaphalangeal (MP) arthrodesis at the thumb. The FDP and EDC tendons are not good choices because they are not independent tendons. The EIP provides power, but the vector of the transfer is not ideal. Transfer of the EC RL would unbalance the wrist.

Question 29

In the diagnosis of a boutonniere deformity, a patient will not present with:

Explanation

A boutonniere deformity refers to a finger in which the PIP joint is in a flexed position and the DIP joint is in a hyperextended position. These deformities may be acute or chronic. With the exception of answer choice D, all of the other answers describe possible presentations of a patient with boutonniere deformity. A patient with active hyperextension at the PIP joint with full flexion at the DIP joint, but no active flexion at the PIP joint has a swan-neck deformity.

Question 30

In the diagnosis of a boutonniere deformity, a patient may present with:

Explanation

A bony boutonniere injury is a fracture of the base of middle phalanx with the central slip of the extensor mechanism attached. With this injury, the patient is unable to actively extend the PIP joint from its flexed position.

Question 31

Horner syndrome includes all of the following except:

Explanation

Horner syndrome is due to disruption of sympathetic innervation and is characterized by enophthalmos not exophthalmos.

Question 32

Axonotmesis involves injury to which of the following structure:

Explanation

Axonotmesis as described in Seddon classification implies injury to the axon and myelin sheath. It is neurotmesis that involves injury to all the three layers.

Question 33

All of the following may be seen with preganglionic lesion EXC EPT:

Explanation

Tinel sign is seen with postganglionic lesions.

Question 34

Weakness of which of the following muscles is not seen with root avulsion:

Explanation

Trapezius is innervated by spinal accessory nerve and thus will not be involved in a brachial plexus lesion. In the case of a preganglionic lesion, ALL muscles innervated by the nerve roots will be affected.

Question 35

In obstetric brachial plexus injury, return of which of the following muscle by 3 months is considered an indicator of plexus recovery:

Explanation

Biceps recovery at 3 months is considered the single most important indicator of recovery in obstetric plexus palsy.

Question 36

A 15-year-old white boy presents to your office with inability to elevate his right shoulder and flex his elbow. He sustained a fall from an all-terrain vehicle 8 weeks ago. He landed on the right shoulder and says his neck was twisted away at the time of fall. He was seen at the local emergency department; skull, chest, cervical and thoracic spine, and shoulder x-rays showed no damage. There was no loss of consciousness and he has no chest pain or breathing difficulties. He was observed in the hospital until stable and was referred to follow up in the hand clinic at 4 weeks and scheduled for an electromyogram. Clinical examination reveals weakness of deltoid, supraspinatus, infraspinatus, teres minor, biceps, brachialis, brachioradialis, and extensor carpi radialis longus. The remainder of his forearm musculature is preserved and he can grasp and release and pinch. Sensations are decreased along the distribution of axillary nerve. There is 3 cm wasting of his arm and 2 cm of his forearm. Tinel sign is positive around the clavicle. Horner signs are absent and his arm lies against the body. The EMG report shows fibrillation potentials in the weak muscles. The parents are concerned and say they have not seen any improvement. The boy reports that he is now able to flex his elbow. When asked to demonstrate you notice that he flexes his wrist and pronates his forearm to swingâ his elbow into flexion. The diagnosis of the boys condition is:

Explanation

The muscles involved have C 5, C 6 root innervations. There are multiple findings that rule out a preganglionic lesion: positive Tinel sign, functioning rhomboids and serratus anterior, absent Horner syndrome. The electromyogram finding confirms the clinical finding (it does not show subclinical involvement of any other muscle). Neuropraxia usually resolves in 6 weeks and EMG shows fibrillation, both of which are inconsistent with neuropraxia. Brachial plexus neuritis (Parsonage-Turner syndrome) has an acute presentation following a painful episode involving the whole arm. There is significant history of fall from an all terrain vehicle in this case.

Question 37

A 15-year-old white boy presents to your office with inability to elevate his right shoulder and flex his elbow. He sustained a fall from an all-terrain vehicle 8 weeks ago. He landed on the right shoulder and says his neck was twisted away at the time of fall. He was seen at the local emergency department; skull, chest, cervical and thoracic spine, and shoulder x-rays showed no damage. There was no loss of consciousness and he has no chest pain or breathing difficulties. He was observed in the hospital until stable and was referred to follow up in the hand clinic at 4 weeks and scheduled for an electromyogram. Clinical examination reveals weakness of deltoid, supraspinatus, infraspinatus, teres minor, biceps, brachialis, brachioradialis, and extensor carpi radialis longus. The remainder of his forearm musculature is preserved and he can grasp and release and pinch. Sensations are decreased along the distribution of axillary nerve. There is 3 cm wasting of his arm and 2 cm of his forearm. Tinel sign is positive around the clavicle. Horner signs are absent and his arm lies against the body. The EMG report shows fibrillation potentials in the weak muscles. The parents are concerned and say they have not seen any improvement. The boy reports that he is now able to flex his elbow. When asked to demonstrate you notice that he flexes his wrist and pronates his forearm to swing his elbow into flexion. What is the level of lesion:

Explanation

The muscles involved have C 5, C 6 root innervations. There are multiple findings that rule out a preganglionic lesion: positive Tinel sign, functioning rhomboids and serratus anterior, absent Horner syndrome. The electromyogram finding confirms the clinical finding (it does not show subclinical involvement of any other muscle). Neuropraxia usually resolves in 6 weeks and EMG shows fibrillation, which is inconsistent with neuropraxia. Brachial plexus neuritis (Parsonage-Turner syndrome) has an acute presentation following a painful episode involving the whole arm. There is significant history of fall from an all terrain vehicle in this case.

Question 38

A 15-year-old white boy presents to your office with inability to elevate his right shoulder and flex his elbow. He sustained a fall from an all-terrain vehicle 8 weeks ago. He landed on the right shoulder and says his neck was twisted away at the time of fall. He was seen at the local emergency department; skull, chest, cervical and thoracic spine, and shoulder x-rays showed no damage. There was no loss of consciousness and he has no chest pain or breathing difficulties. He was observed in the hospital until stable and was referred to follow up in the hand clinic at 4 weeks and scheduled for an electromyogram. Clinical examination reveals weakness of deltoid, supraspinatus, infraspinatus, teres minor, biceps, brachialis, brachioradialis, and extensor carpi radialis longus. The remainder of his forearm musculature is preserved and he can grasp and release and pinch. Sensations are decreased along the distribution of axillary nerve. There is 3 cm wasting of his arm and 2 cm of his forearm. Tinel sign is positive around the clavicle. Horner signs are absent and his arm lies against the body. The EMG report shows fibrillation potentials in the weak muscles. The parents are concerned and say they have not seen any improvement. The boy reports that he is now able to flex his elbow. When asked to demonstrate you notice that he flexes his wrist and pronates his forearm to â swing his elbow into flexion. What is the least helpful test in further management of this patient:

Explanation

Computer tomography scan of the cervical spine will not be of any use as it will neither show the pseudomeningoceles nor provide any information on brachial plexus. C T scan may be needed in case of a suspected neck injury but does not form part of a brachial plexus work up.

Question 39

A 15-year-old white boy presents to your office with inability to elevate his right shoulder and flex his elbow. He sustained a fall from an all-terrain vehicle 8 weeks ago. He landed on the right shoulder and says his neck was twisted away at the time of fall. He was seen at the local emergency department; skull, chest, cervical and thoracic spine, and shoulder x-rays showed no damage. There was no loss of consciousness and he has no chest pain or breathing difficulties. He was observed in the hospital until stable and was referred to follow up in the hand clinic at 4 weeks and scheduled for an electromyogram. Clinical examination reveals weakness of deltoid, supraspinatus, infraspinatus, teres minor, biceps, brachialis, brachioradialis, and extensor carpi radialis longus. The remainder of his forearm musculature is preserved and he can grasp and release and pinch. Sensations are decreased along the distribution of axillary nerve. There is 3 cm wasting of his arm and 2 cm of his forearm. Tinel sign is positive around the clavicle. Horner signs are absent and his arm lies against the body. The EMG report shows fibrillation potentials in the weak muscles. The parents are concerned and say they have not seen any improvement. The boy reports that he is now able to flex his elbow. When asked to demonstrate you notice that he flexes his wrist and pronates his forearm to â swingâ his elbow into flexion. The plan of management in this boy 5 months after injury with no clinical improvement should be:

Explanation

Neurotization is appropriate in preganglionic lesions. Around 6 months with no evidence of recovery is ideal time for plexus exploration. Further observation will not change the picture and tendon transfers are reconstructive procedures, which are done at a later stage.

Question 40

A 15-year-old white boy presents to your office with inability to elevate his right shoulder and flex his elbow. He sustained a fall from an all-terrain vehicle 8 weeks ago. He landed on the right shoulder and says his neck was twisted away at the time of fall. He was seen at the local emergency department; skull, chest, cervical and thoracic spine, and shoulder x-rays showed no damage. There was no loss of consciousness and he has no chest pain or breathing difficulties. He was observed in the hospital until stable and was referred to follow up in the hand clinic at 4 weeks and scheduled for an electromyogram. Clinical examination reveals weakness of deltoid, supraspinatus, infraspinatus, teres minor, biceps, brachialis, brachioradialis, and extensor carpi radialis longus. The remainder of his forearm musculature is preserved and he can grasp and release and pinch. Sensations are decreased along the distribution of axillary nerve. There is 3 cm wasting of his arm and 2 cm of his forearm. Tinel sign is positive around the clavicle. Horner signs are absent and his arm lies against the body. The EMG report shows fibrillation potentials in the weak muscles. The parents are concerned and say they have not seen any improvement. The boy reports that he is now able to flex his elbow. When asked to demonstrate you notice that he flexes his wrist and pronates his forearm to â swingâ his elbow into flexion. What will be the most important indication for an early exploration in this case:

Explanation

An important indication for early exploration is recovery of a distally supplied muscle (EC RL â C 6) in the absence of a proximally supplied muscle (biceps â C 5). Trick movements are adaptive movements employed by the patient by recruiting other muscles (use of flexor-pronator as elbow flexors in this patient). Bony deformity is a late sequela and biceps recovery at 3 months is important in obstetric brachial palsy.

Question 41

A 15-year-old white boy presents to your office with inability to elevate his right shoulder and flex his elbow. He sustained a fall from an all-terrain vehicle 8 weeks ago. He landed on the right shoulder and says his neck was twisted away at the time of fall. He was seen at the local emergency department; skull, chest, cervical and thoracic spine, and shoulder x-rays showed no damage. There was no loss of consciousness and he has no chest pain or breathing difficulties. He was observed in the hospital until stable and was referred to follow up in the hand clinic at 4 weeks and scheduled for an electromyogram. Clinical examination reveals weakness of deltoid, supraspinatus, infraspinatus, teres minor, biceps, brachialis, brachioradialis, and extensor carpi radialis longus. The remainder of his forearm musculature is preserved and he can grasp and release and pinch. Sensations are decreased along the distribution of axillary nerve. There is 3 cm wasting of his arm and 2 cm of his forearm. Tinel sign is positive around the clavicle. Horner signs are absent and his arm lies against the body. The EMG report shows fibrillation potentials in the weak muscles. The parents are concerned and say they have not seen any improvement. The boy reports that he is now able to flex his elbow. When asked to demonstrate you notice that he flexes his wrist and pronates his forearm to â swingâ his elbow into flexion. The most important function that needs to be restored in this boy is:

Explanation

Elbow flexion is central to management of brachial plexus management because it serves the most important function of feeding.

Question 42

An 18-month-old boy is brought to your office for a clawing deformity of his right hand. The parents inform you that he was born full term after a difficult delivery complicated by shoulder dystocia. The boy weighed 9½ lbs at birth. The child had a brief episode of apnea with an APGAR score of 5 at birth and needed resuscitation and admission to the natal intensive care unit. Parents recall having noted a bump on his right clavicle, which was tender and was diagnosed as clavicle fracture. They also noticed a week later that the child did not flex the fingers of his right hand. The neonatologist had informed them that the fracture is managed conservatively and the absence of finger flexion is due to the fracture and shall recover. They were warned that the recovery can be prolonged and can take up to 2 years. The boy has grown well and has achieved his milestones on time. His immunization is complete for his age. You find a healthy, playful boy who tends to use his left hand to reach for objects. His right hand has extension at all the metacarpophalangeal (MC P) joints of the fingers while his proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are flexed. His thumb is an adducted position and it is difficult to passively bring it to full abduction. There is obvious wasting of the hand and forearm. The child is able to move the arm well with no abnormalities noticed at the shoulder, elbow, and the wrist. The x-ray of his chest shows a healed clavicle fracture with no evidence of diaphragmatic paralysis. There is no evidence of Horner Syndrome and the grasp reflex is absent. The diagnosis of this boyâ s condition is:

Explanation

This is a case of obstetric brachial plexus injury involving the C 8, T1 roots (Klumpke Palsy). Erbâ s palsy involves upper roots only. Combined nerve injuries can present in a similar fashion; however, low ulnar and median nerve lesions will not have weakness of flexor digitorum profundus (FDP) and flexor digitorum superficialis (FDS). History of large baby, shoulder dystocia and clavicle fracture point to a difficult labor. The most common type of brachial plexus injury related to birth is Erbâ s palsy, which is usually associated with a breech presentation. Isolated Klumpkeâ s palsy is rare, and involvement of C 8, T1 usually occurs as part of global plexus injury.

Question 43

An 18-month-old boy is brought to your office for a clawing deformity of his right hand. The parents inform you that he was born full term after a difficult delivery complicated by shoulder dystocia. The boy weighed 9½ lbs at birth. The child had a brief episode of apnea with an APGAR score of 5 at birth and needed resuscitation and admission to the natal intensive care unit. Parents recall having noted a bump on his right clavicle, which was tender and was diagnosed as clavicle fracture. They also noticed a week later that the child did not flex the fingers of his right hand. The neonatologist had informed them that the fracture is managed conservatively and the absence of finger flexion is due to the fracture and shall recover. They were warned that the recovery can be prolonged and can take up to 2 years. The boy has grown well and has achieved his milestones on time. His immunization is complete for his age. You find a healthy, playful boy who tends to use his left hand to reach for objects. His right hand has extension at all the metacarpophalangeal (MC P) joints of the fingers while his proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are flexed. His thumb is an adducted position and it is difficult to passively bring it to full abduction. There is obvious wasting of the hand and forearm. The child is able to move the arm well with no abnormalities noticed at the shoulder, elbow, and the wrist. The x-ray of his chest shows a healed clavicle fracture with no evidence of diaphragmatic paralysis. There is no evidence of Horner Syndrome and the grasp reflex is absent. The level of the lesion in this boyâ s case is:

Explanation

It is difficult to clinically differentiate between a pre- and post ganglionic lesion of C 8, T1 in a child. Absence of Hornerâ s syndrome and hemi- diaphragmatic palsy in this case indicates that this is not a preganglionic lesion. Also, the ability of the child to hold his head suggests that the paravertebral muscles are functional as is true in postganglionic lesions.

Question 44

An 18-month-old boy is brought to your office for a clawing deformity of his right hand. The parents inform you that he was born full term after a difficult delivery complicated by shoulder dystocia. The boy weighed 9Â½ lbs at birth. The child had a brief episode of apnea with an APGAR score of 5 at birth and needed resuscitation and admission to the natal intensive care unit. Parents recall having noted a bump on his right clavicle, which was tender and was diagnosed as clavicle fracture. They also noticed a week later that the child did not flex the fingers of his right hand. The neonatologist had informed them that the fracture is managed conservatively and the absence of finger flexion is due to the fracture and shall recover. They were warned that the recovery can be prolonged and can take up to 2 years. The boy has grown well and has achieved his milestones on time. His immunization is complete for his age. You find a healthy, playful boy who tends to use his left hand to reach for objects. His right hand has extension at all the metacarpophalangeal (MC P) joints of the fingers while his proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are flexed. His thumb is an adducted position and it is difficult to passively bring it to full abduction. There is obvious wasting of the hand and forearm. The child is able to move the arm well with no abnormalities noticed at the shoulder, elbow, and the wrist. The x-ray of his chest shows a healed clavicle fracture with no evidence of diaphragmatic paralysis. There is no evidence of Horner Syndrome and the grasp reflex is absent. Appropriate surgical management in this case should be:

Explanation

Neurotization has not been shown to produce successful results for lower root involvement and is performed for preganglionic lesions. At 18 months, exploration and nerve grafting must still be carried out. Neurolysis is reserved for cases in which the recovery is partial or plateaus. Tendon transfers in children younger than 3 years of age do not work as well. Younger children do not cooperate well in their rehabilitation and it is also difficult to decide upon the functioning motors for transfer.

Question 45

An 18-month-old boy is brought to your office for a clawing deformity of his right hand. The parents inform you that he was born full term after a difficult delivery complicated by shoulder dystocia. The boy weighed 9Â½ lbs at birth. The child had a brief episode of apnea with an APGAR score of 5 at birth and needed resuscitation and admission to the natal intensive care unit. Parents recall having noted a bump on his right clavicle, which was tender and was diagnosed as clavicle fracture. They also noticed a week later that the child did not flex the fingers of his right hand. The neonatologist had informed them that the fracture is managed conservatively and the absence of finger flexion is due to the fracture and shall recover. They were warned that the recovery can be prolonged and can take up to 2 years. The boy has grown well and has achieved his milestones on time. His immunization is complete for his age. You find a healthy, playful boy who tends to use his left hand to reach for objects. His right hand has extension at all the metacarpophalangeal (MC P) joints of the fingers while his proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are flexed. His thumb is an adducted position and it is difficult to passively bring it to full abduction. There is obvious wasting of the hand and forearm. The child is able to move the arm well with no abnormalities noticed at the shoulder, elbow, and the wrist. The x-ray of his chest shows a healed clavicle fracture with no evidence of diaphragmatic paralysis. There is no evidence of Horner Syndrome and the grasp reflex is absent. Which of the following set of investigations is most appropriate in this case:

Explanation

In obstetric brachial palsies, it is important to confirm the level of lesion (pre- or postganglionic). Magnetic resonance imaging, computer tomography-myelogram or myelogram are comparable modalities. A manual muscle test is vital in documenting the muscle weakness as well as to assess progress on serial exams. SSEP is used intraoperatively and a histamine test usually does not form part of standard tests.

Question 46

An 18-month-old boy is brought to your office for a clawing deformity of his right hand. The parents inform you that he was born full term after a difficult delivery complicated by shoulder dystocia. The boy weighed 9½ lbs at birth. The child had a brief episode of apnea with an APGAR score of 5 at birth and needed resuscitation and admission to the natal intensive care unit. Parents recall having noted a bump on his right clavicle, which was tender and was diagnosed as clavicle fracture. They also noticed a week later that the child did not flex the fingers of his right hand. The neonatologist had informed them that the fracture is managed conservatively and the absence of finger flexion is due to the fracture and shall recover. They were warned that the recovery can be prolonged and can take up to 2 years. The boy has grown well and has achieved his milestones on time. His immunization is complete for his age. You find a healthy, playful boy who tends to use his left hand to reach for objects. His right hand has extension at all the metacarpophalangeal (MC P) joints of the fingers while his proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints are flexed. His thumb is an adducted position and it is difficult to passively bring it to full abduction. There is obvious wasting of the hand and forearm. The child is able to move the arm well with no abnormalities noticed at the shoulder, elbow, and the wrist. The x-ray of his chest shows a healed clavicle fracture with no evidence of diaphragmatic paralysis. There is no evidence of Horner Syndrome and the grasp reflex is absent. The goal of reconstructive surgery in this boy should include all of the following EXC EPT:

Explanation

This child has already developed contractures of first web space, which probably will not respond to passive stretching. Fusion of MP joint is not needed as tendon transfers will be able to provide for lateral and tip pinch as well as opposition.

Question 47

Which of the following lesions has the highest risk of malignant degeneration:

Explanation

Olliers disease (multiple enchondromatosis) is associated with deformities of the axial skeleton and larger, unilateral lesions. The combination of multiple enchondromatosis and venous-lymphatic vascular malformations (angiomas) is termed Maffuccis syndrome. Maffucciâ s syndrome is associated with a higher rate of degeneration into chondrosarcoma than in Ollierâ s disease. Malignant change of solitary lesions is rare, but a sudden increase in pain or size should raise suspicion of degeneration.

Question 48

The most common primary bone tumor of the hand is:

Explanation

Enchondromas account for more than 90% of primary bone tumors of the hand.

Question 49

Prolonged nonsteroidal anti-inflammatory drugs (NSAIDs) cure which of the following lesions:

Explanation

An average 33-month course of treatment with NSAIDs cures osteoid osteoma. The prostaglandin E2 in osteoid osteoma is likely the reason for this response.

Question 50

The most common primary bone tumor in the hand is:

Explanation

Enchondroma preferentially occurs in the hand, most commonly in the phalanges and metacarpals, and is the most common primary tumor of bone found in the hand.

Question 51

A 65-year-old female undergoes volar locked plating for a distal radius fracture. During the procedure, the surgeon places a screw in the most ulnar hole of the distal row of the plate. Which tendon is at the highest risk of injury from this specific screw if it penetrates the dorsal cortex?

Explanation

A dorsal prominent screw in the most ulnar hole of the distal row of a volar plate puts the extensor digiti minimi (EDM) tendon at risk within the 5th extensor compartment. The EPL is typically at risk from screws in the 3rd compartment, such as those near the Lister tubercle.

Question 52

A 13-year-old obese male presents with acute-on-chronic left hip pain and inability to bear weight. Radiographs confirm a severe, unstable slipped capital femoral epiphysis (SCFE). Which of the following factors is most strongly associated with the development of avascular necrosis (AVN) in this patient?

Explanation

Unstable SCFE, defined clinically by the inability to bear weight even with crutches, has the highest association with developing AVN. While aggressive reduction can also cause AVN, clinical instability is the primary patient-related prognostic factor.

Question 53

Following an anterior cruciate ligament (ACL) reconstruction using a bone-patellar tendon-bone autograft, a patient develops a "cyclops lesion". Which of the following clinical findings is most characteristic of this complication?

Explanation

A cyclops lesion (localized anterior arthrofibrosis) typically presents with a loss of terminal knee extension and an audible or palpable clunk. It is caused by a fibrovascular nodule forming anterior to the ACL graft, often impinging in the intercondylar notch.

Question 54

During a total hip arthroplasty using a posterolateral approach, the surgeon identifies and protects the sciatic nerve. Which of the following is the most frequent cause of sciatic nerve palsy following a primary total hip arthroplasty?

Explanation

Nerve stretching due to excessive limb lengthening (typically > 4 cm) is the most common cause of sciatic nerve palsy after THA. The peroneal division of the sciatic nerve is particularly susceptible due to its anatomical fixation at the fibular head.

Question 55

A 55-year-old male presents with right arm pain, weakness in wrist extension, and numbness in the dorsal web space between the thumb and index finger. The triceps reflex is normal, but the brachioradialis reflex is diminished. Which cervical nerve root is most likely compressed?

Explanation

C6 radiculopathy typically presents with weakness in wrist extension and elbow flexion, diminished brachioradialis reflex, and sensory changes in the thumb and index finger. C7 radiculopathy would typically involve triceps weakness and a diminished triceps reflex.

Question 56

Which type of collagen is the predominant structural protein synthesized by hypertrophic chondrocytes during the endochondral ossification phase of fracture healing?

Explanation

Hypertrophic chondrocytes specifically synthesize Type X collagen during endochondral ossification. This marks the transition from cartilage matrix production to calcification and subsequent bone formation.

Question 57

A 16-year-old male undergoes neoadjuvant chemotherapy followed by wide excision of a distal femur osteosarcoma. Histologic analysis of the resected specimen reveals 95% tumor necrosis. What does this histologic finding primarily indicate?

Explanation

Tumor necrosis of 90% or greater (Huvos grade III or IV) following neoadjuvant chemotherapy is the single most important prognostic indicator for overall survival in osteosarcoma. It indicates a strong favorable response to the current chemotherapy regimen.

Question 58

A patient sustains a laceration to the volar aspect of the index finger over the proximal phalanx (Zone II). During surgical repair, both the flexor digitorum superficialis (FDS) and profundus (FDP) tendons are found to be completely transected. What is the current standard of care regarding the repair of these tendons?

Explanation

The current standard of care for Zone II flexor tendon injuries is primary repair of both the FDS and FDP tendons. Repairing both helps maintain the blood supply via the vincula, reduces the risk of joint contracture, and provides a smoother gliding surface.

Question 59

A 24-year-old athlete sustains a hyperplantarflexion injury to the midfoot. Radiographs show no obvious fractures, but weight-bearing films reveal a 3 mm diastasis between the base of the first and second metatarsals. What is the most appropriate definitive management?

Explanation

A Lisfranc ligament injury with >2 mm diastasis indicates instability and requires surgical stabilization. In a young athlete without extensive articular comminution or preexisting arthritis, ORIF is generally preferred over primary arthrodesis.

Question 60

When performing a total knee arthroplasty, the surgeon notices that the knee is tight in flexion but well-balanced in extension. Which of the following is the most appropriate surgical step to correct this mismatch?

Explanation

A knee that is tight in flexion but balanced in extension has a tight flexion gap. Downsizing the femoral component (with anterior referencing) decreases the posterior femoral offset, effectively increasing the flexion gap without altering the extension gap.

Question 61

A 6-year-old child presents with a grade IV L5-S1 isthmic spondylolisthesis. The child has a severe waddling gait and hamstring tightness but no focal neurologic deficits. What is the most appropriate surgical treatment?

Explanation

For high-grade dysplastic or isthmic spondylolisthesis in children, in situ posterolateral fusion is highly successful and remains the gold standard. Aggressive reduction maneuvers carry a significantly higher risk of L5 nerve root injury and are generally avoided if no focal deficits exist.

Question 62

An anteroposterior compression (APC) type III pelvic ring injury involves complete disruption of the anterior ring and posterior sacroiliac complex. Which specific posterior ligamentous structure disruption distinguishes an APC II from an APC III injury?

Explanation

An APC II injury involves disruption of the anterior sacroiliac, sacrotuberous, and sacrospinous ligaments, but the strong posterior sacroiliac ligaments remain intact. An APC III injury involves disruption of these posterior sacroiliac ligaments, resulting in complete global instability.

Question 63

A 28-year-old male sustains a proximal pole scaphoid fracture. The fracture is displaced by 2 mm. Which of the following represents the most reliable blood supply to the scaphoid, explaining the high risk of avascular necrosis in this fracture pattern?

Explanation

The scaphoid receives 70-80% of its blood supply from the dorsal carpal branch of the radial artery, which enters at the dorsal ridge and flows retrograde to the proximal pole. Proximal pole fractures disrupt this retrograde supply, leading to a high rate of avascular necrosis.

Question 64

Galvanic corrosion in orthopedic implants occurs when two dissimilar metals are placed in physical contact within a conductive fluid environment. Which of the following metal combinations carries the highest risk of significant galvanic corrosion?

Explanation

Mixing stainless steel with titanium or cobalt-chromium alloys creates a strong galvanic cell due to significant differences in their electrochemical potentials. This combination is generally avoided in orthopedic surgery to prevent accelerated corrosion and subsequent implant failure.

Question 65

A 4-month-old infant is diagnosed with developmental dysplasia of the hip (DDH) after an ultrasound demonstrates a dislocated left hip with an alpha angle of 40 degrees. A Pavlik harness is prescribed. Which complication is most likely if the hip is positioned in excessive flexion?

Explanation

Excessive flexion (>120 degrees) in a Pavlik harness can stretch and compress the femoral nerve, leading to a femoral nerve palsy. Excessive abduction, on the other hand, is the primary risk factor for avascular necrosis of the femoral head.

Question 66

A 40-year-old male undergoes operative repair of an acute Achilles tendon rupture using a minimally invasive technique. Sural nerve injury is a known complication. At what level relative to the lateral malleolus does the sural nerve typically cross the lateral border of the Achilles tendon?

Explanation

The sural nerve typically crosses the lateral border of the Achilles tendon approximately 9-12 cm proximal to the calcaneal insertion. Minimally invasive or percutaneous repairs in this proximal zone place the nerve at significant risk.

Question 67

A patient with suspected cervical spondylotic myelopathy demonstrates an inverted supinator reflex. This clinical finding is most specific for compression at which spinal cord level?

Explanation

The inverted supinator reflex indicates a lower motor neuron lesion at C5-C6 (loss of brachioradialis reflex) and an upper motor neuron lesion below this level (hyperactive finger flexors). It is highly specific for cervical myelopathy at the C5-C6 level.

Question 68

During an ilioinguinal approach to the acetabulum, massive bleeding is encountered near the posterior aspect of the superior pubic ramus. This is most likely due to an injury of the corona mortis, which is an anastomotic vessel connecting the external iliac system to which of the following arteries?

Explanation

The corona mortis is a vascular anastomosis between the external iliac (or inferior epigastric) and obturator vessels. It is located on the posterior aspect of the superior pubic ramus and is at high risk during anterior pelvic approaches.

Question 69

A 45-year-old female experiences a sudden pop in her posterior knee while squatting. MRI reveals a complete radial tear of the posterior horn of the medial meniscus at its bony attachment. Biomechanically, this injury is most equivalent to:

Explanation

A complete meniscal root tear disrupts the hoop stresses of the meniscus, resulting in radial extrusion under load. Biomechanically, this alters peak articular contact pressures equivalently to a total meniscectomy, predisposing to rapid cartilage degeneration.

Question 70

A 35-year-old male presents with scaphoid nonunion advanced collapse (SNAC). Radiographs show arthritis involving the radioscaphoid and capitolunate joints, but the radiolunate joint is spared. Which surgical procedure is most appropriate?

Explanation

In Stage III SNAC wrists, arthritis involves the capitolunate joint, making a proximal row carpectomy contraindicated due to an arthritic capitate head. Scaphoid excision with four-corner arthrodesis relies on the spared radiolunate joint for residual motion.

Question 71

A 32-year-old female presents with an expansile lytic lesion in the distal femur. Biopsy confirms a Giant Cell Tumor of bone. She is prescribed denosumab prior to surgery. What is the mechanism of action of this medication?

Explanation

Denosumab is a human monoclonal antibody that binds to RANKL, preventing its interaction with the RANK receptor on osteoclasts and giant cells. This effectively halts the severe osteolysis characteristic of Giant Cell Tumors.

Question 72

In the workup for a suspected periprosthetic joint infection (PJI) of the knee, synovial fluid analysis reveals a highly elevated alpha-defensin level. What is the biological source of alpha-defensin in this context?

Explanation

Alpha-defensins are antimicrobial peptides released primarily by neutrophils in response to an infectious pathogen. They have demonstrated excellent sensitivity and specificity as a synovial fluid biomarker for diagnosing periprosthetic joint infections.

Question 73

A 12-year-old obese male undergoes in situ pinning for a stable slipped capital femoral epiphysis (SCFE). Post-operatively, it is discovered that the screw penetrated the anterosuperior quadrant of the femoral head into the joint unrecognized. What is the most likely complication?

Explanation

Unrecognized intra-articular hardware penetration during SCFE fixation is the most common iatrogenic cause of chondrolysis. It leads to rapid, irreversible loss of articular cartilage and profound joint stiffness.

Question 74

In articular cartilage, which zone contains the highest concentration of proteoglycans and chondrocytes that are oriented perpendicular to the articular surface?

Explanation

The deep zone of articular cartilage contains the highest concentration of proteoglycans and the lowest water content. The collagen fibers and chondrocytes in this zone are arranged perpendicular to the articular surface to effectively resist compressive forces.

Question 75

During surgical exposure for a displaced proximal humerus fracture, preservation of the primary blood supply to the humeral head is critical. Recent anatomical studies indicate which artery provides the majority of the blood supply to the humeral head?

Explanation

Recent anatomical injection studies have demonstrated that the posterior humeral circumflex artery provides the majority (up to 64%) of the blood supply to the humeral head. This challenges the historical belief that the anterior humeral circumflex artery was dominant.

Question 76

A 40-year-old male sustains an acute Achilles tendon rupture. When discussing non-operative management utilizing an early functional rehabilitation protocol versus surgical repair, what outcome is most accurate regarding non-operative management?

Explanation

Modern randomized controlled trials show that when functional, early weight-bearing rehabilitation is utilized, non-operative management has an equivalent re-rupture rate to surgical repair. It avoids the surgical wound complications associated with operative management.

Question 77

When comparing bone-patellar tendon-bone (BPTB) autografts to hamstring autografts for anterior cruciate ligament (ACL) reconstruction, BPTB grafts are historically associated with a higher incidence of which of the following complications?

Explanation

Bone-patellar tendon-bone (BPTB) autografts are favored for their rigid bone-to-bone healing and lower failure rates in high-demand athletes. However, they carry a well-documented higher incidence of donor site morbidity, particularly anterior knee pain and pain with kneeling.

Question 78

A 6-year-old boy sustains a displaced, extension-type supracondylar humerus fracture presenting with a pale, pulseless hand. After closed reduction and percutaneous pinning, the hand becomes well-perfused (pink) with brisk capillary refill, but the radial pulse remains absent. What is the most appropriate next step?

Explanation

A "pink, pulseless" hand following the successful reduction of a supracondylar fracture indicates adequate collateral perfusion. The standard of care is close observation, as the radial pulse typically returns within several days to weeks without necessitating vascular surgery.

Question 79

A 70-year-old female presents with bilateral leg heaviness that worsens with walking and is relieved by leaning forward over a shopping cart. Which of the following anatomic structures is the primary contributor to dorsal compression in this classic presentation?

Explanation

Neurogenic claudication in central lumbar spinal stenosis is frequently driven by ligamentum flavum hypertrophy. The ligament buckles dorsally into the canal during spinal extension, increasing compression, and stretches during flexion, relieving symptoms.

Question 80

A 45-year-old male sustains a high-energy Schatzker IV tibial plateau fracture with a distinct posteromedial shear fragment. Which surgical approach is most appropriate to mechanically buttress this specific fragment?

Explanation

A posteromedial shear fragment requires a posteromedial approach to allow placement of an anti-glide buttress plate at the apex of the fracture. Standard anterolateral approaches do not provide the exposure needed to functionally reduce or support this fragment.

Question 81

Which of the following prognostic factors is the most critical determinant of long-term survival in a patient with high-grade, non-metastatic osteosarcoma of the distal femur?

Explanation

The histologic response to neoadjuvant chemotherapy is the single most important prognostic factor for long-term survival in non-metastatic osteosarcoma. A good response is typically defined as greater than 90% tumor necrosis upon histologic evaluation of the resected specimen.

Question 82

Bone morphogenetic proteins (BMPs) play a crucial role in bone healing via osteoinduction. Which of the following BMPs is an FDA-approved recombinant agent commonly used to enhance anterior lumbar interbody fusion (ALIF)?

Explanation

Recombinant human BMP-2 (rhBMP-2) is heavily utilized and FDA-approved for specific applications, including anterior lumbar interbody fusion (ALIF) and acute open tibial shaft fractures, due to its potent osteoinductive capabilities.

Question 83

During the ultrasound evaluation of a 6-week-old infant for developmental dysplasia of the hip (DDH), the Graf classification is utilized. What anatomical landmark defines the baseline for measuring the alpha angle?

Explanation

In the Graf ultrasound technique, the baseline is drawn along the straight portion of the ilium. The alpha angle is measured between this baseline and the bony acetabular roof line, with an angle greater than 60 degrees considered normal.

Question 84

A 12-year-old boy with a history of panhypopituitarism presents with a stable, slipped capital femoral epiphysis (SCFE) of the left hip. What is the most appropriate management regarding the contralateral right hip?

Explanation

Prophylactic contralateral pinning is strongly recommended in patients with SCFE associated with underlying endocrine disorders, such as panhypopituitarism or hypothyroidism, due to the extremely high risk of bilateral involvement.

Question 85

A 45-year-old male sustains a high-energy Schatzker VI bicondylar tibial plateau fracture with a displaced posteromedial coronal shear fragment. Which surgical approach and fixation strategy is most appropriate for addressing this specific posteromedial fragment?

Explanation

Displaced posteromedial coronal shear fragments in bicondylar tibial plateau fractures require direct visualization and buttress or anti-glide plating via a posteromedial approach to adequately resist vertical shear forces and prevent varus collapse.

Question 86

A 55-year-old active male underwent a total hip arthroplasty with a ceramic-on-ceramic bearing surface two years ago. He now complains of a squeaking noise from the hip during deep flexion, without pain. Radiographs show a well-fixed implant with the acetabular component in 55 degrees of inclination and 25 degrees of anteversion. What is the most likely cause of the squeaking?

Explanation

Squeaking in ceramic-on-ceramic THA is most commonly associated with edge loading. This typically occurs when the acetabular cup is placed in excessive inclination or anteversion, leading to stripe wear on the ceramic head.

Question 87

A 62-year-old woman sustained a nondisplaced distal radius fracture treated in a cast for 4 weeks. Six weeks after cast removal, she reports a sudden inability to extend her thumb at the interphalangeal joint. What is the most appropriate definitive management for her current condition?

Explanation

Delayed extensor pollicis longus (EPL) rupture after a nondisplaced distal radius fracture is best treated with an extensor indicis proprius (EIP) to EPL tendon transfer. Primary repair is typically not feasible due to retracted and degenerated tendon ends.

Question 88

A 45-year-old male presents with severe neck pain radiating down his right arm, associated with numbness in the thumb and index finger. Examination reveals a diminished brachioradialis reflex and weakness in wrist extension. Which cervical nerve root is most likely affected?

Explanation

A C6 radiculopathy classically presents with numbness in the thumb and index finger, weakness in wrist extension and elbow flexion, and a diminished brachioradialis reflex.

Question 89

In the evaluation of a suspected Lisfranc injury, the primary stabilizing ligament of the tarsometatarsal joint complex originates from which structure and inserts onto which structure?

Explanation

The Lisfranc ligament is an interosseous ligament that originates from the lateral aspect of the medial cuneiform and inserts onto the medial base of the second metatarsal, providing critical stability to the midfoot.

Question 90

A 14-year-old boy is diagnosed with high-grade osteosarcoma of the distal femur. He completes neoadjuvant chemotherapy and undergoes wide surgical resection. Which of the following is the most important prognostic factor for his long-term survival?

Explanation

The degree of tumor necrosis (histologic response) following neoadjuvant chemotherapy is the single most important prognostic indicator for overall survival in patients with high-grade, non-metastatic osteosarcoma.

Question 91

Bone morphogenetic protein-2 (BMP-2) promotes osteoblast differentiation and bone formation primarily by binding to cell membrane receptors and activating which of the following intracellular signaling pathways?

Explanation

BMPs bind to serine/threonine kinase receptors on the cell membrane, which subsequently phosphorylate and activate the intracellular Smad 1/5/8 pathway to upregulate osteogenic transcription factors like Runx2.

Question 92

During an anterior cruciate ligament (ACL) reconstruction, if the femoral tunnel is inadvertently placed too far anteriorly (shallow), what is the most likely clinical consequence during knee range of motion?

Explanation

An anteriorly placed femoral tunnel places the graft anterior to the isometric axis of rotation. This causes the ACL graft to be pathologically tight in flexion, potentially limiting knee flexion, and excessively loose in extension.

Question 93

A 6-week-old female is being treated with a Pavlik harness for developmental dysplasia of the hip (DDH). At her follow-up examination, she is noted to have a new inability to actively extend her knee on the treated side. What is the most likely cause of this complication?

Explanation

Femoral nerve palsy is a known complication of Pavlik harness treatment, typically caused by excessive hyperflexion of the hips compressing the nerve against the inguinal ligament. It manifests as a loss of active knee extension and usually resolves with temporary harness adjustment.

Orthopedic Prometric Exam Preparation MCQs - Part 1

Orthopedic Prometric Exam Preparation MCQs - Part 8

Orthopedic Prometric Exam Preparation MCQs - Part 8

Chapter Index