Orthopedic Ob Basic Review | Dr Hutaif Basic Science Re -...

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There is legal precedent for banning a scholarship athlete from participation in college athletics if the physician feels that it presents a significant physical risk to the athlete. The courts have decided that the athlete has no constitutional right to participate in NCAA sports, and as a team physician you must advise your athlete and the school as to the best course of action. The athlete must be allowed to keep his or her college scholarship.

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The figure is a stress-strain diagram representing specific metal subjected to increasing tensile stress. The portion of the curve from A to B is a straight line demonstrating a proportional increase in strain for each increase in tensile stress. If the stress is removed at any point between A and C, the material will return to its original shape, returning back along the original curve without permanent deformation. This is termed elastic behavior. If the applied stress causes strain beyond point C, then permanent deformation occurs and returns along a different path to a different zero stress point. This is termed plastic behavior. The point C at which the material stops behaving in an elastic manner and begins behaving in a plastic manner is the elastic limit or yield point. Point D represents a point on the curve of plastic deformation. Point E is the fracture point when the stress on the material creates enough strain that the material fractures.

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The only reported cases of HIV transmission with tissue transplantation occurred more than 20 years ago. The only reported cases of tuberculosis and hepatitis B occurred more than 50 years ago. The donor-associated clostridium infection occurred in 2001. The facility was not AATB-accredited (American Association of Tissue Banks) and the local AATB facility refused the graft. It is necessary for the surgeon using the allograft tissue to be aware of the current status of tissue regulation, and procurement and processing procedures.

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The incidence of preimplantation positive cultures of musculoskeletal allografts used for anterior cruciate ligament reconstruction has varied between 4.8% and 13.3%.
Interestingly, in none of the studies evaluating this issue did any of the patients implanted with a "contaminated" graft develop a clinical infection. The results of the current literature suggest that the treatment of
low-virulence organisms is unnecessary if no evidence of clinical infection exists. Preimplantation cultures do not appear to correlate with clinical infection. Therefore, the routine culture of allograft tissue is not recommended.

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Although theoretically the intra-articular environment is slightly more immune privileged, the role of immunogenicity is related more to bone than soft tissue. Therefore, the bone- patellar tendon-bone used for ACL reconstruction would have the highest risk of immunogenicity if storage techniques and harvest techniques were similar. This also is true for bone plugs associated with meniscal allografts.

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Carcinoembryonic antigen (CEA) is most closely associated with colorectal carcinoma.
Lang reviews the science behind identification and utilization of cancer antigens for diagnosis, treatment response monitoring, and vaccine purposes.
Incorrect answers:
1.Carbohydrate antigen 125 (CA-125) is seen in ovarian cancer. 3.Carbohydrate antigen 19-9 (CA-19-9) is seen in pancreatic cancer. 4.Cancer antigen 15-3 (CA-15-3) is seen in breast cancer.
5.Alpha fetoprotein (AFP) can be seen in many cancers, but is most commonly seen in hepatocellular carcinomas.

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Gout is an inflammatory arthritis caused by the presence of monosodium urate crystals in the joint. It is characterized acutely by a painful joint that remits after 1 to 2 weeks and recurs periodically. The diagnosis of gout can be made by confirming the presence of monosodium urate crystals in the joint fluid
aspirated from the inflamed joint. Patients with gout may also have tophaceous deposits within the skin or bursae of the extremities. Elevated urine pH, serum uric acid, and serum phosphate can all be associated with numerous conditions and are not specific to gout. Calcium pyrophosphate crystals are associated with chondrocalcinosis (pseudogout).

Chronic Vitamin D deficiency leads to problems with bone health and has been shown to increase the risk of falls in the elderly. Appropriate supplementation of Vitamin D has been shown to decrease this risk. Conversion in the skin decreases with age and may be nearly nonexistent in darkly pigmented individuals. Vitamin D3 is the preferred form for supplementation, but D2 is the form most available by prescription in the US. Hypervitaminosis D is rare and very high doses can be tolerated without significant concern for toxicity. Because the patient has sustained one insufficiency fracture, she is at risk for insufficiency fractures in other skeletal locations, rendering expectant observation insufficient. Her serum calcium is normal, and with a low Vitamin
D level, calcium utilization in her system would be inadequate. Bisphosphonate therapy in addition to calcium and vitamin D supplementation may provide a good long-term solution, but should not be instituted until the bone mineral imbalance has been adequately corrected. Surgical fixation of this fracture is not indicated, particularly in lieu of improving symptoms.

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The signs and symptoms of hyperparathyroidism are similar to those in patients with diffuse skeletal metastases. Serum markers are very helpful in making the diagnosis. In this patient, the radiograph shows multiple lesions in the tibia and proximal fibula that have a variable appearance. For example the mid-tibial lesion is radiolucent and slightly expansile whereas the more proximal tibial lesions are radiodense. The proximal fibula lesion is mixed (radiolucent/radiodense). These findings would be very uncommon in patients with myeloma, metastatic disease, or multicentric giant cell tumor. The histopathology shows a bland fibrous stroma with multiple multinucleated
giant cells. On higher power, the stromal cells are spindled and the giant cells are relatively small in contrast to giant cell tumor where the giant cells are larger and the stromal cells are more rounded with nuclei that closely resemble those in the giant cells.
There is blood extravasation (stromal
hemorrhage) and hemosiderin deposition. The constellation of findings is most consistent with brown tumors due to hyperparathyroidism (secondary to a parathyroid adenoma in this patient).

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The patient has been on alendronate for 10 years and has evidence of a proximal diaphyseal fatigue fracture. These have been associated with long- term use of bisphosphonates. Staging studies have failed to show systemic disease, and while metastasis with an unidentifiable primary does occur, it would be unlikely to present with this radiographic appearance, now recognized to be classic for stress fractures associated with chronic bisphosphonate usage. Hydrochlorothiazide does not cause calcium wasting. Vitamin D-resistant rickets would be a long-standing event and would present much earlier in life, often with pronounced deformities. Whereas the patient's progression to intolerance of weight bearing likely has led to some degree of disuse osteopenia, the underlying problem is the long-term bisphosphonate exposure.

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Sensory neuropathy is the most common complication seen with interscalene regional block.

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Cathepsin K is an enzyme produced and released by osteoclasts at the ruffled border that functions to resorb bone. Cathepsin K inhibitors are being clinically evaluated as potential anti-resorptive drugs for use in osteoporosis treatment. Other proteins associated with osteoclasts include tartrate-resistant acid phosphatase (TRAP) and calcitonin receptor.
Illustration A is a drawing that depicts the action of cathepsin k within osteoclasts.

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Rickets is a disorder of bones in children that results from decreased calcium available in the blood resulting in poor mineralization of bone that can lead to fractures and deformity. The most common cause of rickets is from vitamin D deficiency but it can also be caused by poor nutrition or gastrointestinal
disease that results in poor calcium absorption such as celiac disease or severe diarrhea from other causes. Rickets is not primarily a physeal disorder. Osteogenesis imperfecta is caused by a defect in type I collagen. A defect in
the ext-1 gene is often seen in patients with multiple hereditary exostoses. Fibrous dysplasia also can result in bone deformity and fractures due to production of dysplastic fibrous bone but is not caused by calcium or vitamin D deficiency.

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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.

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Locked plating constructs with long-working lengths provide flexible but stable constructs that promote (not inhibit) endochondral ossification. Because of the longer working length they are not stiff, and these fractures do not heal with intramembranous ossification which occurs in bones like the calvarium. Direct osteonal healing is usually seen with constructs
where absolute stability is achieved through interfragmentary compression, unlike in this case.

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The AAOS recommendation is to complete the correct surgery, repair the incorrect surgery to as close to normal as possible, and then discuss it openly with the family after the surgery is complete. Prompt informing is necessary. Aborting the surgery then results in the patient requiring a second anesthesia and surgical time needlessly.

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Osteocyte cell processes travel through canaliculi to interconnect with other osteocytes and cells on the bone surfaces. Osteoblasts are cells that produce bone matrix and are seen rimming immature bone. Osteoclasts are large multinucleated cells that resorb bone and are found in Howship's lacunae. Megakaryocytes and histiocytes are found in marrow but not mature bone cortex.

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Jehovah's witnesses beliefs regarding blood products stems from direct interpretation of passages from the bible. The use of crystalloid, starch products such as Hetastarch and colloids are accepted. Typically Jehovah's witnesses will accept most medical treatment but refrain from the use of blood products including whole blood, packed red cells, platelets, white cells, or plasma. Any autologous transfusion, whether from the patient themself or donor directed, is forbidden. The use of cell-saver type processes is a matter of individual choice by the patient. The use of hemoglobin-based oxygen carriers are now accepted by many patients but it is important to respect the wishes of each individual patient. It is very important to discuss preoperatively with the patient and family their wishes and thoughts on what is acceptable to use. Many facilities have adopted
bloodless-surgery protocols and committees that definitively outline the measures that can be used and take into consideration the many ethical issues involved in taking care of these patients.

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Specificity refers to the proportion of individuals who are truly free of the designated disorder who are so identified by the test. Sensitivity refers to the proportion of individuals who truly have the disorder who are so identified by the test. Positive predictive value refers to the proportion of individuals with a positive test who have the disorder. Negative predictive value refers to the proportion of individuals with a negative test who are free of the disorder.
Accuracy is the overall ability to identify patients with the disorder (true positives) and without the disorder (true negatives) in the study population.

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An occurrence policy provides coverage for all claims made during employment irrespective of when it is filed (during or postemployment) and therefore is the best option. Claims made policy only covers suits for the time employed. A prepurchased "tail" is needed to provide coverage for cases that occurred during employment but filed postemployment. Nose coverage is applicable if the surgeon was previously employed and did not have tail coverage from previous employment, but this surgeon just emerged from training where it is not applicable. Claims made without tail coverage is unwise because the surgeon would be unprotected or have to purchase his own policy postemployment.
Only in certain situations does sovereign immunity exist, and generally not in a for-profit system. Occurrence coverage with nose coverage
is incorrect because it does not apply to this surgeon with no previous employment or claims policy lacking tail coverage.

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A type II error (also known as a beta error) occurs when results demonstrate that two groups are similar when, in reality, they are different (with regard to the statistic being measured). Type I errors show that a difference exists when, in reality, no difference exists. A statistically insignificant result may lead an investigator to conclude that no difference exists between two groups; this may be correct (and therefore not a type II error). The concept of
`fragile` p-values is that small sample sizes may result in wide variability of p- values with only one change in a data point for a given group. This singular change could be a chance occurrence, but it still can affect the statistical significance of the outcomes analysis.
Fragility of p-values is limited by increasing sample sizes. Negative predictive value is the
proportion of patients with negative test results who are correctly diagnosed.

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To establish negligence, certain criteria must be met. 1) A duty was owed by the surgeon (in this case, yes, a relationship was established). 2) The duty was breached, where the provider failed to meet the standard of care (there
was a technical error, but it was corrected). 3) The breach caused an injury. In this case, the patient had an outcome that was very acceptable, as
documented with outcome studies, for femur fractures. Also, the rotational error and locking distally would have had little impact on the hip, whereas antegrade nailing itself is expected to result in some objective impairment of the hip in some patients. 4) Damages were incurred as a result. In this case, the patient returned to work and could not rock climb which could be reasonably expected with a femur fracture in some patients, and cannot be causally linked to the corrective surgery. For all practical purposes, the patient had a very acceptable outcome. Thus, settling the case for an error would be rather permissive and the important issue is that the surgeon recognized the problem, addressed it, and fulfilled his or her postoperative responsibility. The case is very defendable, and thus it is unlikely to be lost. Defending the case and alleging no error is incorrect because there was an error. The surgeon should never function outside of his or her legal counsel once a suit is filed.

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A case control series starts with the occurrence of a specific disease or observation, and then compares data on those individuals to a similar group without the disease (control group) in order to identify potential risk factors for the development of the disorder. A case series is an observational study in which an investigator follows a series of patients who received a specific treatment, recording the results and outcomes of that treatment. A meta- analysis is the combination of several separate studies that look at similar hypotheses in an effort to create a larger patient population for analysis. A cohort study looks for the incidence of a specific outcome in two groups (cohorts) of patients who are similar with the exception of a particular
research variable (risk factor).

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Osteocalcin is the most specific marker of the osteoblast phenotype and is expressed only in mature osteoblasts. TGF-B is a growth factor involved in the differentiation of multiple cell lines. For bone, TGF-B plays a role in stem cell differentiation into mesenchymal stem cells along osteoblast pathways. COLIIA1 is the gene for Type II Collagen and is involved in chondrocyte differentiation. cFOS is involved in osteoclast differentiation. In regards to
bone metabolism, IL-1 stimualtes osteoclastic bone resorption.

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Empathy during the interview demonstrates compassion and earns the patient's trust; which, in turn, enables the patient to discuss any agenda or concerns he or she may otherwise feel uncomfortable revealing. It is also important to engage the patient to establish a trusting relationship and thus understand all the factors impacting the patient. A formal attitude toward the patient makes it difficult to engage the patient to be "drawn in." An engaged patient is more comfortable, reliable, and thorough when providing a history. Closed-end, yes-no questions do not allow the patient to detail all of the subtle nuances of their condition and its effect on their life. Taking copious notes likewise prevents engagement of the patient and the distraction of taking
notes may cause the physician to miss an important detail. It is better to lean forward in a chair when interviewing a patient because this suggests the physician is genuinely interested, whereas leaning back in a chair suggests the physician is simply waiting for the patient to finish talking. Avoid interrupting the patient when talking.

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This is the definition of maximum medical improvement (MMI). The patient has essentially reached the plateau of his improvement.
Functional capacity evaluations (FCE) are based upon a theoretical model of comparing job demands to worker capabilities. The results of FCEs are often used to determine musculoskeletal capacity to return to work.
Strong et al. reported on the use of FCE in the Workers' Compensation system, and note how these FCE results are required by employers to determine the level of return to work of their employees. They also mention that the reports are frequently perceived with a negative tone. The employees reported a wider range of restrictions in their varied life roles than did the FCE reports, which deal more narrowly with work roles.
Pransky et al. reported that although FCE's are relied upon for determination of ability to perform physical work, several scientific, legal, and practical concerns persist. They note that test criteria often do not accurately reflect real-life job requirements or performance, and subjective evaluation remains common. They conclude that more research into predictive linking of FCE outcomes with occupational outcomes is necessary to determine their role in the Workers' Compensation system.
Incorrect Answers:
1: A functional capacity evaluation (FCE) is set of tests, practices and observations that are combined to determine the ability of the evaluated to function in a variety of circumstances (most often employment) in an objective manner.
3: Permanent disability is any lasting disability that results in a reduced earning capacity after maximum medical improvement is reached; this implies that MMI must be reached before this is determined.
4: Impairment rating is an objective data point obtained by a physician reviewing the patient's overall condition during a functional capacity evaluation.
5: This is the process a patient uses to tell their employer they want a personal physician to treat them for a work injury.

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The most appropriate first step is to notify the medical liability carrier. The medical liability carrier will assign an attorney who is likely to be more appropriate. A review by a colleague may be requested by the defense attorney but that should be at their discretion. Patient apology is appropriate early on when and if you discover an error.
Records should be reviewed, but never altered.

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Although a recent push for prospective, randomized trials has been advocated by multiple orthopaedic journals, many studies published continue to be of Level 4 evidence (retrospective case series). Case series represented 64% of all studies reviewed by Freedman and associates in 2001 from the British and American volumes of Journal of Bone and Joint Surgery and from Clinical Orthopaedics and Related Research.
Obremskey and associates published that
58.1% of all studies from nine orthopaedic journals were Level 4 evidence. Further investigation of more current trends is likely warranted with the
current emphasis on publishing higher level-of-evidence studies in orthopaedic journals.

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The patient has the classic symptoms of a pulmonary embolism. Symptoms of pulmonary embolism of polymethylmethacrylate (PMMA) following vertebral augmentation may occur with a delay. A symptomatic pulmonary embolism following vertebroplasty can occur either by migration of acrylic or the migration of fat and bone marrow cells. The MRI scan reveals a new superior endplate fracture involving L2. With this now being the third consecutive vertebral compression fracture in 2 months, one must be suspicious that these represent pathologic fractures, rather than osteoporosis. Risk factors for venous thromboembolic disease include increasing age, prolonged immobility, surgery, trauma, malignancy, pregnancy, estrogenic medications (eg, oral contraceptive pills, hormone therapy, tamoxifen [Nolvadex]), congestive heart
failure, hyperhomocystinemia, diseases that alter blood viscosity (eg, polycythemia, sickle cell disease, multiple myeloma), and inherited thrombophilias. In addition to the risk associated with embolization of PMMA, the patient has been immobile for 7 days and was ultimately diagnosed with multiple myeloma.

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Osteoclasts are derived from cells of the monocyte/macrophage lineage. They are multinucleated and develop by fusion of mononuclear precursors, a process that requires receptor activator for nuclear factor kappa-B ligand (RANKL) and macrophage-colony stimulating factor (M-CSF). RANKL is secreted by osteoblasts in response to inflammatory signals and is a key component of inflammation-mediated osteolysis. OPG binds to and sequesters RANKL, thus inhibiting osteoclast differentiation and activity.
BMP and IGF-1 are potent regulators of osteoblast differentiation and activation. TNF is a cytokine secreted by macrophages and degranulating platelets infiltrated in the fracture site and impacts a variety of cells, not osteoclasts.

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This is a prospective comparative study but is not randomized or blinded and
is therefore a Level II therapeutic study. To qualify as Level I, it would need to be a high- quality randomized trial with narrow confidence intervals regardless of a significant difference or no difference in outcomes. Level III would be
case-control studies or retrospective comparisons. Level IV is case series and Level V is expert opinion.

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Physeal fractures typically occur through the zone of provisional calcification. Answers 3-5 are all part of the hypertrophic zone which is labeled "D" on the histologic illustration A. Illustration B shows the relationship of the physeal zones to the epiphysis and metaphysis of a growing bone. However, the stress concentration is greatest in the sub-layer where there is a transition from the soft cartilagenous physis to the harder calcific metaphysis.
As discussed in the review by Ballock and O'Keefe, the growth plate is a remarkable portion of the skeleton that requires precise coordination between multiple endocrine, paracrine, and autocrine signaling systems. While fractures can occur in any portion of the growth plate, the zone of provisional calcification is the most common.

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Despite the initiatives by the American Academy of Orthopaedic Surgeons and the
JCAHO, the number of reported cases of wrong-site surgery has continued to increase yearly since 1997. Because reporting of these events is not mandated by JCAHO, it is possible that the continued increase is due to a greater awareness of the problem and thereby a greater level of reporting. The U.S. estimates are 12.7 wrong-site surgeries per million cases performed. Orthopaedic surgery and podiatry are the most common specialties associated with wrong-site surgery (41%) followed by general surgery (21%), neurosurgery (14%), and urologic surgery (11%).

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Evidence-based health care extends the application of the principles of evidence-based medicine to all professions associated with health care. This concept is becoming more important because data will be used by the different parties for their decision making (policy makers, health insurances, hospitals, doctors, and the public). Cost-benefit analysis refers to the conversion of effects into the same monetary terms as the costs and compares them. Cost- effectiveness analysis refers to the conversion of effects into health terms and describes the costs for some additional health gain (eg, cost per additional event prevented). Cost-utility analysis refers to the conversion of effects into personal preferences (or utilities) and describes how much it costs for some additional quality gain (eg, cost per additional quality-adjusted life-year).
Decision analysis refers to the application of explicit, quantitative methods to analyze decisions under conditions of uncertainty.

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Numerous drugs are associated with an increased risk of osteoporosis in
adults, including oral corticosteroids, androgen-deprivation therapy, aromatase inhibitors, protease inhibitors, selective serotonin reuptake inhibitors,
prolactin-raising antiepileptic agents and many cytotoxic agents.
Additionally, a number of disease states are associated with osteoporosis, including endocrinopathies such as hyperparathyroidism, thyrotoxicosis and type I diabetes, hypogonadism, chronic glucocorticoid therapy, malnutrition, malabsorption states, chronic immobilization, rheumatoid arthritis, alcoholism, vitamin D deficiency, and multiple myeloma.
NSAIDs have not been shown to increase risk of osteoporosis.

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Although the early use of FDS as a transfer to restore finger extension in patients with radial nerve palsy was performed by passing the tendon through the interosseous membrane, Nalebuff and Patel later modified this procedure for the rheumatoid arthritis patient by passing the FDS radially, around the radius in a dorsal direction. They felt that this provided a number of advantages, including: 1. technical ease, 2. avoidance of synovial disease on the dorsum of the wrist, and 3. correction of ulnar deviation of the fingers through the line of pull from the radial side of the forearm.

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The patient has gout. Unfortunately, gout may mimic several conditions affecting the small joints of the hand, including infection. The histologic specimen shows negatively birefringent intracellular rods consistent with gout. The histology rules out giant cell tumor and calcium pyrophosphate deposition disease.

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Because the phrenic nerve lies in close proximity to the site of anesthetic injection, temporary hemidiaphragmatic paresis is a very common side effect of interscalene brachial plexus block. Pulmonary function and chest wall mechanics may be slightly compromised, but can easily be compensated in a healthy patient. Therefore, with
sufficient oxygenation, aggressive assessments or treatments such as arterial blood gas measurements,
emergent spiral CT scans, chest tube insertions, or endotracheal intubation are not warranted. For this stable patient, continued monitoring with gradual withdrawal of oxygen is the most appropriate treatment.

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Total elbow arthroplasty is the treatment of choice. The patient has end-stage rheumatoid involvement of the ulnohumeral and radiocapitellar joints. Given the advanced nature of the disease and evidence of bony erosion, arthroscopic
synovectomy and interposition arthroplasty are unlikely to provide lasting benefit or functional improvement. Elbow arthrodesis and resection arthroplasty are considered salvage techniques and are generally not considered as a primary treatment method.

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There are many causes of inability to extend the MCP joints in a patient with rheumatoid arthritis. The most common cause is rupture of the extensor tendons. An intact tenodesis test suggests that the extensor tendons are intact, thus surgical exploration is not indicated and would not confirm the diagnosis. The patient has normal alignment of the fingers without ulnar deviation, suggesting that there are no MCP dislocations to account for the inability to extend the MCP joints; therefore, radiographs would not confirm the diagnosis. The most likely cause of inability to extend the fingers in this patient is posterior interosseous nerve (PIN) palsy. Electrodiagnostic studies would confirm the presence of PIN palsy. An MRI of the elbow may show synovitis at the radiocapitellar joint, which can cause the PIN palsy. This finding however, is nonspecific and many patients without PIN palsy would also demonstrate synovitis at the radiocapitellar joint.
Therefore, although an MRI would be helpful in localizing a potential cause of PIN compression, it would not in itself confirm the diagnosis.

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Types I and II collagen are the predominant types of collagen found in the intervertebral disk. Type I collagen is present in the highest concentration in the annulus fibrosus and type II collagen in the nucleus pulposus. Type V collagen is present in small concentration in the annulus fibrosus. Type VI collagen is a non-fibrillar, short-helix collagen found in both the annulus and nucleus. Type XII is present in the annulus fibrosus only.

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Kramer and associates conducted a retrospective review during an "epidemic" period to identify the risk factors associated with a sudden increase in the rate of surgical site infections. They found in a multivariate analysis that the use of morphine nerve paste resulted in a 7.6-fold increase in postoperative surgical wound debridement, and an 11% rate of surgical site complications. There is no evidence in the literature verifying the incidence of postoperative urinary retention and arachnoiditis.

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Young's modulus of elasticity is a measure of the stiffness of a material and its ability to resist deformation. This is the slope of the stress/strain curve in the elastic range. The highest modulus is ceramic, followed by: cobalt-chrome alloy, stainless steel, titanium, and then cortical bone.

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Bisphosphonates have been shown to decrease osteolysis after total joint replacement surgery.
Aseptic loosening and osteolysis are the primary causes of implant failure in total joint arthroplasty. Early findings indicate that bisphosphonates upregulate bone morphogenetic protein-2 production and stimulate new bone formation, leading to decreased osteolysis in total joint replacement surgery. While
further investigation is required, bisphosphonates may play a future role in improving the long-term duration of joint arthroplasties.
Shanabhag et al. reviewed the use of bisphosphonates and reported that they had the potential to enhance bone ingrowth into implant porosities, prevent bone resorption under adverse conditions, and dramatically extend the long- term durability of joint arthroplasties. They recommended further investigation into the subclasses to determine which ones are most beneficial.
Arabmotlagh el al. performed a prospective study on use of alendronate after total hip arthroplasty. They reported that the alendronate-treated patients had significantly less periprosthetic bone loss on DXA scans after 6 years.
Illustration A shows evidence of osteolysis (arrows) around a total hip arthroplasty.
Incorrect Answers:
2-5: These medication classes do not decrease osteolysis after total joint arthroplasty.

The radiograph and sagittal T2-weighted MRI scan show multilevel degenerative changes and subaxial subluxations with anterolisthesis at C3-C4 and C4-C5 and retrolisthesis at C5-C6. In addition, there is evidence of midcervical kyphosis. Such findings are often seen in patients with rheumatoid arthritis. Patients with osteomyelitis typically show increased signal intensity in the disks and vertebral bodies. Patients with ankylosing spondylitis typically show ankylosis of the disks and vertebral bodies. Age-related degenerative changes typically manifest as degenerative disk disease with occasional single- level spondylolisthesis, but not typically multilevel spondylolisthesis, as seen in this patient. The spinous processes are intact; these changes do not appear to be postoperative.

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Continuous fluoroscopy and cineradiography exposes the patient and personnel to markedly increased levels of direct and scatter radiation exposure. Continuous fluoroscopy should be limited to only what is absolutely needed for safe completion of the procedure. By orienting the cathode ray
tube beneath the patient and placing the image intensifier as close as clinically possible to the patient, scatter radiation exposure to the personnel is minimized.

of the mechanism mediating this effect. Whereas all of the above have been postulated as explanations, more recent studies have
demonstrated that nicotine delivered via a transdermal patch significantly enhanced posterior spinal fusion in rabbits. Thus it appears that the effects of smoking on fracture healing are multifactorial and not yet fully understood.

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Impairment of a healthcare professional is the inability or impending inability to practice according to accepted standards as a result of substance use, abuse, or dependency (addiction). A surgeon (resident, fellow or attending) who discovers chemical impairment, dependence, or incompetence in a colleague or supervisor has the responsibility to ensure that the problem is identified and treated. Mechanisms exist for the proper identification and treatment of the impaired physician. Misconduct can be reported to state and local agencies. One must be sure to act in good faith with reasonable evidence when reporting such an incident. If a patient is at risk for immediate harm or injury by an impaired physician, one should assert authority and relieve the physician of the patient care and then address the problem with the senior hospital staff as soon as possible. The referenced article by Baldisseri is a review on the ethics of dealing with impaired healthcare professionals, with a focus on physicians.

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The patient has MRI findings throughout her lumbar spine consistent with old compression fractures. Given the imaging findings and advanced age, she is at high risk for osteoporosis and subsequent fragility fractures. Management should consist of a DEXA scan to evaluate her degree of osteoporosis and
begin medical treatment as appropriate. Because acute fracture is unlikely, and she has no neurologic compromise, neither bracing nor surgical treatment is indicated.

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The radiograph shows isolated degeneration in the talonavicular joint that is symmetric. The symmetry of the degeneration is characteristic of an inflammatory arthritis. In the absence of trauma, isolated arthritis in this joint is uncommon. The navicular is normal sized, ruling out Kohler disease (as well as the patient being in the wrong age group). There are no erosions indicative of osteomyelitis. Osteochondritis dissecans appears as focal osteochondral lesions, which are not present in the radiograph.

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The patient has a severe rheumatoid forefoot deformity involving all metatarsophalangeal joints. Coughlin and Mann have found that 90% of patients have excellent and good results with combined first metatarsophalangeal fusion and lesser metatarsal head resection. Keller arthroplasty does not provide a stable platform for walking and is associated with recurrent deformity and pain. The first metatarsophalangeal joint replacement has not been shown to provide reliable long- term results. Osteotomies may be indicated in patients without erosive joint changes. The Lapidus procedure is an arthrodesis of the first tarsometatarsal joint, which would not address the patient's arthritic first metatarsophalangeal joint.

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It is illegal to alter the medical record under any circumstance. If a documentation error has occurred, you may addend the medical record by identifying the error and noting the correction.
The review article by Bal discusses medical practice and highlights the four legal elements that must be proven in litigation: (1) a professional duty owed to the patient; (2) breach of such duty; (3) injury caused by the breach; and (4) resulting damages.

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Patients with reflex sympathetic dystrophy (RSD) have a history of trauma, minor rather than major (eg, Colles fracture), in about 50% to 65% of cases. The condition may also follow a surgical procedure. Patients usually have symptoms and signs of RSD including: pain, described as burning, throbbing, shooting, or aching; hyperalgesia; allodynia; and hyperpathia. There are trophic changes within 10 days of onset of RSD in 30% of the extremities affected, including stiffness and edema and atrophy of hair, nails, and/or skin.
Finally there can be autonomic dysfunction, such as abnormal sweating, either
in excess or anhydrosis, heat and cold insensitivity, or redness or bluish discoloration of the extremities. Shingles, also called herpes zoster or zoster, is a painful skin rash caused by the varicella zoster virus (VZV). VZV is the same virus that causes chickenpox. After a person recovers from chickenpox, the virus stays in the body.
Usually the virus does not cause any problems; however, the virus can reappear years later, causing shingles. Charcot arthropathy is a progressive condition of the musculoskeletal system that is characterized by joint dislocations, pathologic fractures, and debilitating deformities. This disorder results in progressive destruction of bone and soft tissues at weight-bearing joints; in its most severe form, it may cause significant disruption of the bony architecture. In patients with diabetes, the incidence of acute Charcot arthropathy of the foot and ankle ranges from
0.15% to 2.5%. Acute Charcot arthropathy almost always appears with signs of inflammation. Profound unilateral swelling, an increase in local skin temperature (generally, an increase of 3° to 7° above the nonaffected foot's skin temperature),
erythema, joint effusion, and bone resorption in an insensate foot are present. These characteristics, in the presence of intact skin and a loss of protective sensation, are often pathognomonic of acute Charcot arthropathy. Cellulitis is an infection of the skin.
Examination would reveal erythema, edema, and pain. Osteomyelitis is an infection of the bone. Examination may reveal edema, drainage, and pain.

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Whereas all of the factors will have an impact on frame rigidity and stability, the single biggest factor is the pin diameter because it has an exponential effect.

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Locking screw fixation is a relatively new option in the armamentarium of orthopaedic surgeons treating fractures. The understanding of the biomechanics, implications to healing, and optimal indications and surgical techniques is still in evolution. A periprosthetic proximal femur fracture with a stable prosthesis is best treated with open reduction and internal fixation with locking proximal fixation with or without cerclage cables. Diaphyseal fractures treated with compression plating or bridge plating can be treated well with conventional implants unless osteoporosis is severe. An AO/OTA B-type partial articular fracture is also better suited to standard buttress plating with periarticular rafting lag screws. Locking fixation is not always required for a transverse displaced midshaft clavicle fracture.

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Reverse transcription polymerase chain reaction (RT-PCR) is a variant of polymerase chain reaction (PCR) used in molecular biology to generate many copies of a DNA sequence from fragments of RNA. The RNA strand is first reverse transcribed into its DNA complement, followed by amplification of the resulting DNA using polymerase chain reaction. Polymerase chain reaction amplifies short segments of DNA by using the temperature stable DNA polymerase enzyme.

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Each of the answer choices is a risk factor for subsequent fragility fracture, but patient history of a prior fragility fracture is the strongest predictor.
Bouxsein et al reviews the proper care, diagnosis, and prevention of fragility fractures. History of a fragility fracture is the greatest predictor of a future fracture from low energy trauma. Appropriate care includes not only treatment of the fracture itself, but also proper evaluation to identify the etiology of the fracture and appropriate intervention to rectify the underlying pathology. Evaluation includes bone densitometry, lab testing of Vitamin D and calcium.
A T-score compares your bone density to the optimal peak bone density for your gender. It is reported as number of standard deviations below the average. A T-score of -1 to -2.5 is considered osteopenia, and a risk for developing osteoporosis. A T- score of less than -2.5 is diagnostic of osteoporosis.

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Alendronate is a bisphosphonate that inhibits the ruffled border of the osteoclast. When used long term, this class of medication prevents the normal bone remodeling process. Long-term use has recently been shown to be associated with insufficiency fractures of the femur. Osteonecrosis of the jaw has been described but not in other anatomic locations. Scurvy occurs because of a lack of vitamin C and use of bisphosphonates is not associated with
uterine cancer or a detached retina.

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Polylactic acid suture and suture anchors are popular bioabsorbable orthopaedic implants. This material undergoes hydrolysis of the ester background in vivo. Resulting lactic acid enters the tricarboxylic acid (Krebs)
cycle and is excreted as carbon dioxide by the lungs. Polyglycolic acid and poly(p- dioxanone) may also be excreted by the kidneys.

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Studies on animal models have shown that there is a change in collagen fiber type and distribution early in the healing process. There is a higher portion of type III fibers than in
normal ligament initially, but this ratio returns to normal about 1 year after the injury occurs. Healing ligaments show an increased number of collagen fibers, but the number of mature collagen cross-links is
45% of predicted value after 1 year. There is also a decrease in the mass and diameter of the collagen fibers.

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Dkk-1 and sclerostin are proteins that inhibit the binding of the Wnt molecule to receptors LRP5/6. In the absence of sclerostin and Dkk-1, Wnt binds to its receptor, which in turn inhibits phosphorylation of the ß-catenin. The unphosphorylated ß-catenin then builds up in the cytoplasm of the cell, allowing it to be transported to the nucleus of the cell. Once in the nucleus, ß- catenin will lead to upregulation of a series of proteins involved in osteoblast formation differentiation. Knocking out or inhibiting sclerostin or Dkk-1 results in increased bone mass secondary to constitutive activation of the Wnt/ß- catenin pathway. The other responses are not directly affected by Dkk-1 or sclerostin. RANKL and RANK are expressed on osteoblasts and osteoclasts, respectively, and are involved in osteoblast-mediated osteoclast activation. BMPs work through SMADs to cause osteoblastic differentiation, and there is reported crosstalk between the Wnt and BMP pathways (but this is an indirect link). Finally, PTH at physiologic levels binds to osteoblasts, causing a series of events that lead to osteoblast-mediated osteoclast activation and subsequent increased bone resorption.

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The growth plate is divided into 5 distinct zones: reserve, proliferative, maturation, hypertrophy, and vascular invasion. During growth-plate chondrocyte hypertrophy, intracellular volume and an increase in chondrocyte height are responsible for most growth of long bones. Other factors that contribute to bone growth are chondrocyte proliferation and matrix synthesis, but to a lesser degree than chondrocyte hypertrophy. Growth plate chondrocytes undergo programmed cell death (apoptosis) after hypertrophy
takes place.

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Mutations of bacterial DNA gyrase can decrease the effectiveness of quinolones. Altered membrane-binding protein is observed with resistance to ?
-lactam antibiotics. Tetracyclines are antibiotics that inhibit bacterial growth by stopping protein synthesis. Three specific mechanisms of tetracycline
resistance have been identified: increased tetracycline efflux, ribosome protection, and tetracycline modification. Alteration of RNA polymerase is found in resistance to rifampin.

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The Heuter-Volkmann principle shows that bone placed in longitudinal tension will tend to stimulate longitudinal growth, and that compressive longitudinal forces inhibit longitudinal growth, making this response the best choice. Hooke's law relates to stress being proportional to strain and is not directly related to bone growth. Kirchhoff's laws apply to electrical circuit design. Wolff's law states that bone remodels in response to mechanical stress, with the correlate that increased stress causes increased growth, and decreased stress leads to bone loss.

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Healing after a tendon repair or rupture has the following stages: inflammatory, cellular proliferation, and remodeling. During the inflammatory phase, neutrophils and macrophages migrate into the injury site and release chemotactic factors that recruit fibroblasts. A tendon is thought to be weakest
5 to 21 days after repair, which coincides with the inflammatory phase. During the proliferative phase, inflammatory cells secrete cytokines and growth
factors (platelet-derived growth factor, insulin-like growth factor, bone morphogenetic protein (BMP)-12 and BMP 13, and transforming growth factor- beta) that promote differentiation of fibroblasts. Fibrosis and decreased cellularity are the hallmarks of the remodeling stage.

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This patient has familial hypophosphatemic rickets, a vitamin D-resistant form of rickets that is an X-linked inherited disorder. Patients are short (< 10th percentile). Varus occurs both in the distal femur and proximal tibia. Patients have increased urinary excretion of phosphorus, leading to hypophosphatemia. Calcium levels are within defined limits and vitamin D levels can be normal as well. Treatment should include phosphate and 1,25 dihydroxy vitamin D3 (calcitriol). Phosphate administration increases the plasma concentration,
which lowers plasma ionized calcium concentration and further reduces plasma calcitriol concentration (removal of hypophosphatemic stimulus). Secondary hyperparathyroidism results because of both hypocalcemia and removal of the
normal inhibitory effect of calcitriol on parathyroid hormone (PTH) synthesis. Elevated PTH levels will increase urinary phosphate excretion, defeating the aim of oral therapy.
Addition of calcitriol is necessary to increase the intestinal absorption of calcium and phosphate to prevent secondary hyperparathyroidism. Massive doses of vitamin D alone can restore normal radiographic appearances to the epiphyses, but normal growth is not restored unless phosphate replacement is adequate.

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Training increases turnover of type I collagen, promoting both synthesis and degradation of collagen and a net increase synthesis of type I collagen in tendon-related tissue.
Strenuous endurance training has resulted in decreased collagen cross-links, suggesting increased collagen turnover, but decreased collagen maturation. In human studies, physical training results in increased turnover of collagen. Synthesis and degradation are elevated initially when beginning an exercise program, but degradation products decrease overall. It is not known if activity levels in humans affect the diameter of collagen fibrils or the cross-sectional area of tendons.