Miscellaneous

Question 1

current indications for primary hemiarthroplasty in setting of proximal humerus fracture?

Answer 1

• most 4 part fxs
• 3 part fxs and dislocations in elderly pts w/ osteoporotic bone
• head splitting articular segment fxs
• chronic anterior or posterior humeral head dislocations w/ more than 40% articular surface involvement
• relative indications: fxs w/ more than 20 deg varus, associated moderate to severe osteopenia, revision surgery for failed osteosynthesis

Question 2

tx of proximal humerus fxs?

Answer 2

-dependent upon the mechanism of injury, the patient’s physiologic age and activity level, the fracture pattern, and rotator cuff integrity. Most of these injuries are nondisplaced or minimally displaced and are associated with a good overall prognosis with nonsurgical treatment and temporary impairment.

Question 3

atypical lipomatous tumors (well-differentiated liposarcomas)

Answer 3

• typically slowly growing
• lipomatous features on MRI
• occasional intralesional stranding
• RING CHROMOSOME AND EXPRESSION OF MDM2, but do NOT have the 12;16 translocation typical of myxoid liposarcomas
• pose risk for local recurrence but do not pose significant risk for metastatic spread

Question 4

To be most effective, poller screws should be placed at which location when treating a proximal third tibial shaft fracture that tends to adopt a valgus position?

Answer 4

• LATERAL to the nail in the METAPHYSEAL SEGMENT
• As a general principle, the blocking screw is optimally placed within the metaphyseal fragment on the concave side of the deformity in question

Question 5

In children undergoing lower-extremity amputations compared to controls who do not require surgery, what is the lowest amputation level at which differences in self-selected walking speed can be detected?

Answer 5

Knee disarticulation
-Children with an amputation through the knee or distal to the knee were able to maintain a normal walking speed without significantly increasing their energy cost. Only when the amputation is above the knee do children walk significantly slower and with an increased energy cost (Jeans et. al, JBJS 2011)

Question 6

features concerning for soft-tissue sarcomas?

Answer 6

For patients with rapidly enlarging painless masses, particularly those that are either large or deep, the diagnosis of a soft-tissue sarcoma should be entertained. Masses exceeding 5 cm in largest dimension that are subfascial and heterogenous on MRI are concerning.

Question 7

staging of sarcomas

Answer 7

Not all sarcomas are reliably positive on a PET scan, so the preferred staging studies are CT scan of the chest and whole-body bone scan. Hematogenous spread of sarcomas is the most common route of metastatic disease, which speaks to the value of chest CT scans. Clear-cell sarcomas (in addition to synovial sarcoma, angiosarcoma, epithelioid sarcoma, and rhabdomyosarcoma) tend to involve lymphatic nodal metastatic disease, so sentinel node biopsy is considered when assessing these tumors. Evidence supports efficacy of sentinel node biopsy for clear-cell sarcomas in particular.

Question 8

The AAOS has a specific code of ethics and professionalism that addresses this issue: “When an orthopaedic surgeon receives anything of value, including royalties, from a manufacturer, the orthopaedic surgeon must disclose this fact to the patient.” It is derived from a broader document developed by the American Medical Association, and is applicable to all physicians. At present, this is an ethical issue receiving greater federal scrutiny. This issue has had a greater effect on the public’s perception of the integrity of the orthopaedic profession.

Answer 8

.

Question 9

Suprapatellar intramedullary nailing for tibia fractures when compared to infrapatellar nailing is associated with?

Answer 9

-less anterior knee pain

Question 10

what factor is most associated w/ delayed union or nonunion of medial opening wedge osteotomies for varus knee OA?

Answer 10

• smoking is most associated

- other factors are obesity and unstable lateral hinge fractures, but to a lesser extent.

Question 11

when using a bridge plate, what is considered to be the working length of the plate?

Answer 11

the screws closest to either side of the fracture site see the most stress, therefore, the distance between the screws closest to the fracture (on either side of it) is the working length
-this is in contrast to rigid compression plating, where the screws at the ends of the plate see the most stress, and therefore the working length of the plate is the distance between the most distal and most proximal screws in the plate

Question 12

Osteogenesis imperfecta is a defect in what?

Answer 12

collagen

Question 13

treatment during early stages of diskitis w/ vertebral osteomyelitis?

Answer 13

IV abx and bracing to prevent late vertebral collapse

Question 14

what is the next best step in evaluating of pt w/ AS or DISH and neck pain after trauma?

Answer 14

MRI

Question 15

tarsal coalition

Answer 15

abnormal connection of 2 or more bones in the foot. Although tarsal coalitions are present at birth, children and adults typically do not show signs of the disorder until early adolescence or later. The exact incidence of the disorder is hard to determine; however, it is caused by a gene mutation that affects cells that produce the tarsal bones. The 2 most common locations for tarsal coalitions are between the calcaneus and the navicular or between the talus and the calcaneus. It is estimated that 1 out of every 100 people may have a tarsal coalition. In 50% of cases, both feet are affected. Tarsal coalitions are rarely discovered until symptoms arise. Symptoms may include stiff and painful feet, a rigid flatfoot, or increased pain or a limp with high-level activities. Upon examination, symptoms may include tenderness in the area of the coalition, loss of motion, rigid flat feet, and arthritic changes of the joint. Imaging studies begin with radiographs. A CT scan can provide bony detail for imaging tarsal coalitions and determining the extent of the coalition and any accompanying degenerative change. MRI can provide details of the soft tissues. Treatment includes nonsurgical care including rest, orthotics, a temporary boot or cast, and injections. Surgical options include resection with interposition of muscle or fatty tissue from another area of the body or fusions when large (exceeding 50% of the joint), more severe coalitions are encountered

Question 16

tx of Osgood-Schlatters?

Answer 16

NSAIDs, activity modification, gentle quad stretching

Question 17

spinal muscular atrophy

Answer 17

• progressive motor weakness that starts proximally and moves distally, w/ significant variability in severity, caused by progressive loss of alpha motor neurons in anterior horn of spinal cord
• autosomal recessive
• SMN gene mutation (all pts w/ SMA lack SMN-1 protein)
• 3 types (type 1 (worst) usually die as infants, type 2 can sit but cant walk, type 3 walk as children but need wheelchair as adults
• ABSENT DEEP TENDON REFLEXES distinguishes it from Duchenne’s muscular dystrophy
• fasciculations are present
• tx non-op w/ Nusinersen and operativelly by tx associated ortho disorders (scoliosis, contractures); treat hip dislocations non-op

Question 18

scoliosis in setting of spinal muscular atrophy

Answer 18

• curve flexibility tends to be higher than for idiopathic curves
• most curves tend to be long, C-shaped, right-sided thoracolumbar curves
• primary surgical goal for correction is to obtain fusion in a position that will maintain sitting balance and prevent decline of pulmonary function
• curve magnitude correlates strongly w/ ambulatory status
• anterior release/fusion is RARELY required to achieve surgical correction s/t flexibility of curve

Question 19

gene mutation in spinal muscle atrophy?

Answer 19

survival motor neuron (SMN) gene

Question 20

progressive replacement of muscle tissue w/ fibrous and fatty tissue, causing calf pseudohypertrophy

Answer 20

Duchenne muscular dystrophy

Question 21

abnormal chondroid production by chondroblasts in the proliferative zone of the physis

Answer 21

Achondroplasia

Question 22

Disturbances in cell metabolism w/ accumulation of sphingolipids in the liver, spleen, and bone marrow

Answer 22

Gaucher Disease

Question 23

Fetal acetylcholine receptor inhibition and non-progressive joint contractures

Answer 23

Arthrogryposis

Question 24

tx of scoliosis in spinal muscular atrophy

Answer 24

In patients age 9 or less with scoliotic curves >40 degrees, they recommend growing rods anchored to the pelvis. In those 10 or older with scoliotic curves >40 degrees, they recommend posterior spinal fusion with pedicle screws

Question 25

gene defect in osteogenesis imperfecta

Answer 25

COL1A1

Question 26

gene defect in pseudoachondroplasia

Answer 26

COMP

Question 27

Duchenne muscular dystrophy genetics

Answer 27

• dystrophin gene on chromosome X
• connects cytoskeleton of muscle fibers to surrounding ECM
• Creatine phosphokinase levels (CPK-MM) are elevated
• deep tendon reflexes are PRESENT

Question 28

Charcot-Marie-Tooth disease genetics

Answer 28

-Duplication of peripheral myelin protein 22 gene (PMP22) on chromosome 17

Question 29

which gene correlates w/ severity of disease in spinal muscular atrophy?

Answer 29

SMN2
-. Affected patients with all types of SMA will have functional loss of both SMN1 genes, so this does not differentiate disease severity. Disease severity depends on the number of functional copies of SMN2 that remain.

Question 30

what mutation causes spinobulbar muscular atrophy?

Answer 30

Androgen receptor mutation

Question 31

common deformity after calcaneus fxs?

Answer 31

The common deformity is varus, loss of height, with increased heel width. Chronic peroneal tendon dislocation can also occur secondary to the deformity.

Question 32

Note that in more than 50% of cases, there are NO IDENTIFIABLE RISK FACTORS for neonatal brachial plexus palsy

Answer 32

-although shoulder dystocia is a significant risk factor, most cases have no identifiable risk factors

Question 33

gene mutation associated w/ achondroplasia?

Answer 33

FGFR3

Question 34

gene mutations associated with pseudoachondroplasia and multiple-epiphyseal dysplasia

Answer 34

COMP

Question 35

gene mutation associated w/ multiple hereditary exostosis

Answer 35

EXT-1

Question 36

Fibrous dysplasia

Answer 36

common benign skeletal lesion that may involve 1 bone (monostotic) or multiple bones (polyostotic) and occurs throughout the skeleton with a predilection for the long bones. The radiographic features of fibrous dysplasia typically illustrate a grayish “ground-glass” pattern that is similar to the density of cancellous bone. The key histologic features of fibrous dysplasia are trabeculae of immature bone, with no osteoblastic rimming, contained within a bland fibrous stroma of dysplastic spindle-shaped cells without any cellular features of malignancy. The etiology of fibrous dysplasia has been linked to an activating mutation in the gene that encodes the α subunit of stimulatory G protein located at 20q13.2-13.3. This leads to a constitutive activation of adenylate cyclase and increased cyclic adenosine monophosphate formation.

Question 37

Nonaccelerated rehabilitation compared to early accelerated rehabilitation protocol for pts undergoing ACL reconstruction?

Answer 37

No significant differences in long-term results with regard to function, reinjury, and successful return to play. These studies did not address timing of return to play with an early accelerated rehabilitation program. At 2 and 3 years postsurgically, there are no differences in laxity, number of graft failures, or KOOS scores.

Question 38

Tx for a symptomatic unstable os odontoideum

Answer 38

Posterior C1-C2 fusion

Question 39

MSIS definition of periprosthetic joint infection (2 major criteria and 5 minor criteria)

Answer 39

PJI is diagnosed if 1 of 2 major criterions is met or 3 of 5 minor criterions are met

Major: a draining sinus communicating with the joint and 2 positive cultures with the same organism.
Minor: elevated synovial WBC, elevated synovial neutrophil percentage, elevated CRP and ESR, increased WBCs per HPF on frozen section, and a single positive culture

Question 40

Compared with ankle arthrodesis, patients with a TAA have superior function walking upstairs, downstairs, and uphill. However, no significant differences are noted on flat surfaces, uneven surfaces, or downhill.

Answer 40

.

Question 41

compartment syndrome is due to what?

Answer 41

compromise of venous outflow relative to arterial inflow

Question 42

Which factor is most important when attempting to prevent interbody graft subsidence in the spine?

Answer 42

Bone quality

Question 43

aging causes progressive changes in the nucleus pulposus including FRAGMENTATION OF PROTEOGLYCANS

Answer 43

.

Question 44

Latarjet procedure

Answer 44

The Latarjet procedure was initially described in 1959 as a modification of the Bristow procedure. It has been used as a primary procedure to address instability, but is used more commonly for patients with instability and glenoid bone loss. In 2000, Burkhart and associates reported a 67% failure rate of the Bankart procedure in patients with an inverted pear-shaped glenoid (glenoid bone loss) or an engaging Hill-Sachs lesion, with a suggestion that a bone graft procedure would be optimal in this population. Complications following the Latarjet procedure have been reported as high as 25%, with the majority attributable to nerve injury, recurrent instability, and arthritis. Many of these complications are likely secondary to surgical technique. A coracoid graft that is placed too laterally or with prominent screws will overhang the glenoid and lead to early degenerative glenohumeral arthritis. A coracoid graft placed too medially can lead to recurrent instability secondary to an ineffective subscapularis sling and bone block. A coracoid graft placed inferiorly indicates dissection close to the axillary nerve, which can place tension on the axillary nerve or cause injury from direct trauma. After harvesting the coracoid graft, the surgeon must find the musculocutaneous nerve as it enters the conjoint tendon on the medial surface about 5 cm distal to the coracoid. Excessive dissection or retraction can lead to musculocutaneous nerve palsy.

Question 45

Osteoid osteoma can most effectively be differentiated from a stress fracture with which diagnostic modality?

Answer 45

An osteoid osteoma radiographically appears as a small nidus. A nidus is a central lucent area of fibro-osseous tumor that is surrounded by bone sclerosis. The nidus is usually smaller than 1.5 cm. Because of the lesion’s small size, a high-resolution CT scan is needed to see the nidus and its relationship to surrounding bone. An evaluation with an MR image without a CT scan or radiographic imaging can result in misdiagnosis because MR imaging often shows reactive cortical bone surrounding the nidus and large amounts of bone and soft-tissue edema in response to inflammation from prostaglandin production. Bone scans can help localize a nidus, especially when patients refer to pain that makes the anatomic location unclear. Positron emission tomography osteoid osteoma images reveal intense focal hypermetabolic activity that can resolve rapidly following radiofrequency ablation.

Question 46

What is the primary barrier to achieving safe health care?

Answer 46

The primary barrier to making substantial changes is not lack of data, knowledge, or expertise, but the fact that many healthcare organizations have dysfunctional cultures that reinforce negative behaviors that block progress. Healthcare cultures become dysfunctional when they cannot consistently deliver a high-quality product and effective care in an efficient, cost-effective manner. More effective, efficient, and satisfying processes for care provision entail systems changes that will impact a variety of stakeholders and drive a change in culture.

Question 47

Anteromedial coronoid facet fractures usually are associated with a posteromedial rotatory mechanism

Answer 47

.

Question 48

At which time is it safe for patients to return to driving after undergoing right total hip arthroplasty (THA)?

Answer 48

2 wks
-Brake reaction time has improved in line with the newer THA techniques. Studies have suggested that patients wait at least 4 to 6 weeks to resume driving; however, Hernandez and associates examined brake reaction time associated with newer THA techniques and found that reaction time returned to presurgical baseline values 2 weeks after surgery.

Question 49

Driving after orthopaedic surgery

Answer 49

The decision to drive after orthopaedic injury or surgery is fraught with legal and safety issues. Although driving is an important part of most patients’ lives, there are no well-established guidelines for determining when it is safe to drive after injury or treatment. Typically, impairment in driving ability is measured by changes in the time needed to perform an emergency stop. Braking function returns to normal 4 weeks after knee arthroscopy, 9 weeks after surgical management of ankle fracture, and 6 weeks after the initiation of weight bearing following major lower extremity fracture. Patients may safely drive 4 to 6 weeks after right total hip arthroplasty or total knee arthroplasty. Patients should not drive with a cast or brace on the right leg. Upper extremity immobilization may cause significant impairment if the elbow is immobilized; however, simple forearm casts may be permissible.
-Marecek et al. JAAOS, 2013.

Question 50

Ortolani and Barlow maneuvers

Answer 50

A standard examination of newborns includes Ortolani and Barlow tests. Performance of the Ortolani test involves moving the flexed and adducted hip into a flexed, abducted position. A positive test finding reveals a discernable reduction of the dislocated hip from “out” to “in” (O-rtolan-I). A negative Ortolani test result may indicate that the hip is not dislocated or that the hip is dislocated but is irreducible. The Barlow test involves moving the flexed abducted hip to a flexed, adducted position; the result is positive when a palpable hip subluxation/dislocation is detected when moving from the abducted to the adducted position. A negative test result can have 2 meanings—either that the hip is stable and not subluxatable or dislocatable or that the hip is dislocated at the beginning of the test and, consequently, no instability can be detected. Other findings in infants with unilateral dislocated hips include asymmetric gluteal folds and asymmetric apparent femoral lengths. Congenital torticollis, congenital knee instability, and metatarsus adductus are frequent concomitant findings in developmental hip dysplasia.

The imaging screening method of choice for newborns with suspected developmental hip dysplasia is ultrasound. Plain radiographs are of limited use because the femoral head ossific nucleus cannot be visualized. Ultrasound is easily performed without sedation or accompanying radiation exposure and is relatively inexpensive. The alpha angle is typically measured during the ultrasound and is defined as the angle measured between a vertical line drawn along the edge of the acetabulum (Perkin line) and a second line drawn along the acetabular roof. The alpha angle should measure more than 60 degrees.

Initial treatment for newborns is accomplished with a Pavlik harness. Risk factors for developmental dysplasia are multifactorial and include a family history in either a parent or a sibling, a primiparous mother, a breech presentation of any kind at the time of birth regardless of delivery method, and female sex.

Question 51

A 6-year-old boy arrives at the emergency room with a right elbow injury after a fall. He has a swollen right elbow with no tenderness to palpation proximal and distal to the elbow joint. He is distally neurovascularly intact. Anteroposterior (AP) and lateral radiographs of the right elbow demonstrate a lateral condyle fracture that is less than 2 mm displaced. What is the most appropriate next step?

Answer 51

Internal oblique radiograph of the elbow
-AP and lateral radiographs of a lateral condyle fracture can lead surgeons to underestimate the degree of displacement. Internal oblique radiographs can more accurately demonstrate displacement of the posterolateral fragment. Without an understanding of the degree of displacement, the other responses are not appropriate. If a complete radiographic series confirms the fracture is more than 2 mm displaced, surgery is needed. If the fracture is less than 2 mm displaced, long-arm casting with radiographic follow-up to ensure there is no displacement is appropriate.

Question 52

Differential diagnosis of hip pain in a young athlete?

Answer 52

The differential diagnosis of hip pain in a young athlete includes femoral neck stress reaction/fracture, sacroiliac arthritis, intra-articular loose body, trochanteric bursitis, osteitis pubis, and hernia.

Question 53

Which of the following is the most important restraint to medial instability of the long head of the biceps tendon?

Answer 53

Tendon of the subscapularis

Question 54

Signs of loose uncemented femoral stems

Answer 54

-radiolucent lines around the porous surface, stem subsidence, pedestal formation distal to the tip of the stem, or stem fracture.

Question 55

Signs of loose cemented femoral stems

Answer 55

radiolucent lines at the implant-cement or bone-cement interfaces, implant subsidence, cement mantle fracture, or stem fracture.

Question 56

Compression neuropathies

Answer 56

Cubital tunnel syndrome is the second-most-common compression neuropathy (after carpal tunnel syndrome). Advanced ulnar neuropathy is characterized by numerous eponymous signs and by motor atrophy (eg, fist dorsal interosseous, adductor pollicis). The first sign to appear is the Wartenberg sign (Figure 89), which involves the small finger resting in an abducted position because of unopposed pull of the extensor digiti minimi (because interossei are weak from ulnar neuropathy). Froment’s sign (Figure 92) is also seen in advanced ulnar neuropathy secondary to weakness of the adductor pollicis and first dorsal interosseous and compensation by the flexor pollicis longus (FPL) (median innervated) and extensor pollicis longus (radial innervated). The AIN provides motor to the FPL, flexor digitorum profundus (FDP) to the index and middle fingers, and to the pronator quadratus. AIN palsy is a motor deficit that can affect all or part of those muscles. Figure 90 shows a “flattened” OK sign that is seen in AIN palsy attributable to weakness of the FPL and FDP to the index finger. PIN palsy is also a pure motor syndrome. It affects the finger and thumb extensors and the extensor carpi ulnaris (ECU) and extensor carpi radialis brevis (ECRB). The extensor carpi radialis longus (ECRL) is innervated by the radial nerve, so, in PIN palsy, the patient will have a weak wrist extension (because there is no ECU and ECRB involvement) in slight radial deviation (because only the ECRL is firing). Low median nerve palsy is a deficit of the median nerve at the wrist/carpal tunnel. As such, the primary motor deficit is of the thenar muscles and, clinically, this results in weakness in opposition attributable to abductor pollicis brevis weakness. This is often treated with an opposition transfer (tendon transfer). Ulnar tunnel syndrome is compression of the ulnar nerve at the wrist. It is less common than cubital tunnel syndrome. The most common etiology is a ganglion cyst, and MRI is helpful when assessing for this condition. Other etiologies include hypothenar hammer syndrome, hook-of-the-hamate fractures, and anomalous muscles.

Question 57

Osteopetrosis

Answer 57

also known as “marble bone,” occurs because osteoclasts do not resorb bone. The condition is not caused by osteoblast dysfunction. With osteopetrosis, the bone becomes so dense that fractures easily occur.

Question 58

What is the most important factor associated with stress shielding?

Answer 58

Pre-op bone mineral density

Question 59

Advantages of a locking plate implant over a 95-degree angled blade plate for fixation of supracondylar femur fractures include…?

Answer 59

improved ability to use with associated coronal fractures

Question 60

Tx of chronic Achilles tendon rupture

Answer 60

For a chronic injury with a gap larger than 5 cm, the recommended procedure is a turndown reconstruction with or without a transfer of the flexor hallucis longus tendon. With a gap between 2 cm and 5 cm, it often is possible to perform a V-Y reconstruction. In gaps smaller than 2 cm, an end-to-end repair usually is possible. Percutaneous Achilles repair is not indicated in chronic ruptures. Osteotendinous allograft reconstruction produces mixed results and is used only in rare cases of chronic distal Achilles tendon rupture.

Question 61

Sacral dysmorphism

Answer 61

• upper sacral body relatively collinear with the iliac crests; steep alar slope; mammillary bodies; large, irregular S1 neural foramina; and a residual S1 disk. The other notable characteristics of tongue-in-groove sacroiliac joint and cortical indentation of the sacral ala
• A patient is diagnosed with sacral dysmorphism if any of these characteristics are present in any degree, ranging from subtle to obvious, but not all characteristics are required.

Question 62

Diaphyseal humeral shaft fractures

Answer 62

• generally considered acceptable and compatible with good function, including those with less than 20° of angulation in the sagittal plane, those with less than 30° of varus or valgus angulation, and those with limb shortening less than 2 to 3 cm
• gross motion at the fracture site at 6 wks post-injury predicts future non-union with 82% sensitivity and 99% specificity; bottom line- if gross motion is present at 6 wks, then schedule pt for ORIF!!