Orthopedics Hyperguide Review | Dr Hutaif General Ortho -...

The most common intraoperative complications are excessive blood loss (53%), followed by hypothermia (11%). Therefore, patients require extensive monitoring of cardiaCrhythm, blood pressure, temperature, and oxygen saturation. They also need active intraoperative warming, which usually consists of a combination of a warming blanket, humidifier, blood/fluid warmer, and heat lamp

Few published reports exist on the risk of deep vein thrombosis (DVT) in patients with sickle cell disease following orthopediCprocedures. In sickle cell disease, platelets do not contribute to the pathophysiology of microvascular occlusion. However, due to spleniCsequestration, patients with sickle cell disease often have thrombocytopenia. Factors associated with vaso-occlusion include the increased adhesion of the sickle cells to the endothelium and the activation of the clotting cascade with thrombin formation. Thrombin induces endothelial retraction resulting in the exposure of proadhesive extracellular components. It also upregulates endothelial expression of P-selectin, which increases binding among erythrocytes, white cells, platelets, and
endothelial cells. Both of these events can facilitate thrombus formation. Following hip surgery, there is already a definable risk of
DVT attributable to surgical trauma and immobility.
The goal of lower limb arthroplasty is optimal pain control with early mobilization to minimize the risk of respiratory and thromboemboliCcomplications. Results of a meta-analysis of DVT after hip surgery suggest that patients with sickle cell disease undergoing THR are best managed with foot pumps and warfarin postoperatively to decrease the likelihood of thromboses in these patients.

The mean age of patients with sickle cell disease undergoing hip surgery is approximately 34 years, with the most frequent procedure being THR for avascular necrosis. Some patients undergo bipolar hemiarthroplasty, which can be complicated by acetabular protrusio. Because hip surgery often is more complex in patients with sickle cell disease, it often is associated with longer anesthesia time and greater blood loss. Mean blood loss in THR in patients with sickle disease is approximately 1200 mL, which is significantly greater than in patients without sickle cell disease

The common genetiCbasis of sickle cell disease is a mutation on chromosome 11 that results in an amino-acid substitution of valine for glutamiCacid at the sixth position of the beta-globin subunit of hemoglobin that results in hemoglobin S (HbS). In the heterozygote carrier, this sickle gene mutation offers potential resistance to endemiCPlasmodium falciparum malaria infections. Diagnosis of the disease is confirmed by hemoglobin electrophoresis

The common genetiCbasis of sickle cell disease is a mutation on chromosome 11 that results in an amino-acid substitution of valine for glutamiCacid at the sixth position of the beta-globin subunit of hemoglobin that results in hemoglobin S (HbS). In the heterozygote carrier, this sickle gene mutation offers potential resistance to endemiCPlasmodium falciparum malaria infections. Diagnosis of the disease is confirmed by hemoglobin electrophoresis

New surgical technique and instrumentation leads to less invasion of the extensor mechanism. The patella is not everted, and the suprapatellar synovial pouch remains untouched

The initial high failure rate of UKA in early reports was related to improper patient selection, incorrect surgical technique, and poor implant design

In total knee arthroplasty (TKA), knee alignment is corrected to an anatomiC6º or 7º of valgus. In UKA, this alignment leads to excessive medial compartment tightness and overload of the opposite lateral compartment. A varus knee in UKA should remain in neutral or a few degrees of varus. In TKA, a flexion contracture can be readily corrected with additional resection of both femoral condyles. In UKA, resection of the single distal femoral condyle helps to correct the flexion contracture but also changes the distal femoral valgus. Ligament releases in UKA are not as predictable as in TKA because only one compartment is replaced in the UKA, and the forces on the opposite compartment are more difficult to balance

Although a successful UKA can eliminate pain and improve the patientâs function, heavy labor and high impact athletiCactivities are not encouraged. High tibial osteotomy allows a patient to perform more aggressive activities

A patientâs symptoms and physical findings should be isolated to one tibiofemoral compartment, but disease can be present in both the right and left knee as long as its just one compartment. Patient history must be thoroughly evaluated to ensure that there are no associated patellofemoral symptoms in the opposite compartment

Kozinn and Scott have emphasized that pain in the patellofemoral joint is a relative contraindication for UKA surgery. Degenerative changes of the patellofemoral joint also affected patient function, but the symptoms were less severe than in patients with patellar impingement. If patients report significant symptoms related to the patellofemoral joint, then UKA is contraindicated

Manufacturing of polyethylene is improving, and cross-linking processes are increasing the wear properties. Most surgeons believe that it is safest to use a thickness of at least 6 mm with conventional polyethylene

Marmor reported no significant increase in the opposite compartment. Kozinn and Scott reported failures due to progression in the opposite compartment; however, this may have been due to over correction of the knee. Berger and colleagues reported minimal change in the opposite compartment with 12-year follow-up radiographs

The minimally onvasive surgical technique for UKA subluxes the patella and leads to less invasion of the extensor mechanism. The patella is not everted and the suprapatellar synovial pouch remains untouched

Although Salmonella infections are highly specifiCto patients with sickle cell disease, the most common organism identified in bone cultures taken from patients with sickle cell disease with osteomyelitis is S aureus. Due to autoinfarction, 95% of individuals develop functional asplenia by age 5 years. This condition has been associated with a decrease in opsonin production and phagocytiCactivity. Thus, in infants with sickle cell disease the major cause of death is pneumococcal sepsis. It has been recommended that patients with sickle cell disease have pneumococcal vaccine administered every 3 to 5 years

First-generation cement technique implies that cement is hand-packed in the shaft of the femur. A cement plug is not used and a lavage of the femoral canal is not performed. Second-generation technique implies that cement is hand-mixed in a bowl,
medullary lavage is performed, and a canal plug is used. Third-generation technique refers to performing high-pressure jet lavage of the femoral canal, brushing the canal of all particles, using a vacuum or centrifuge machine in the mixing procedure, and using external pressurization on a closed canal

When analyzing bone cement for void content and failure in four-part bending, the results show that syringe-mixed bone cement has a greater density and a greater bending modulus and is of greater strength than aerated bowl-mixed cement

The knee should have less than 15° of deformity in varus or valgus and less than 10° flexion contracture. Inflammatory or crystalline-induced arthritis, knee subluxation, gross ligamentous laxity, and obesity are relative contraindications to the procedure. Scott and colleagues found that increased body weight contributed to failure in UKA and suggested that the best candidates are less than 180 lb

In a study involving 121 patients with untreated asymptomatiCosteonecrosis of the femoral head, 110 of the patients went on to develop significant hip pain. Spontaneous resolution of osteonecrosis of the femoral head was not observed in asymptomatiChips

In a randomized prospective study performed by Neumayr and colleagues, physical therapy alone appeared to be as effective as hip core decompression followed by physical therapy in improving hip function and postponing the need for additional surgical intervention at a mean of 3 years after treatment

In the medial UKA with preoperative varus, most of the reviews suggest an alignment of 0° with reference to the anatomiCaxis of the lower extremity or slightly less than 0° with reference to the mechanical axis. In the study by Kennedy and White on 100
UKAs, they reported that superior results were obtained when the postoperative mechanical axis of the operated limb fell in the center of the knee or slightly medial to the center

Numerous risk factors for stress fracture exist. Most commonly, the scenario is doing âtoo much too soon.â Survey data have shown 86% of runners suffering stress fracture have had a change in duration, frequency, or intensity of training immediately prior to injury. The best independent predictors for stress fracture development in women appear to be age of menarche and calf girth

The muscle-tendon unit exerts a protective effect on cortical bone by acting as the major shock absorber. With muscle contraction, cortical bone surface bending strains are reduced. In most weight-bearing bones it is believed that with muscle fatigue, the shock-absorbing effect is lessened and more force is transmitted directly to bone, increasing the likelihood of microdamage accumulation

Any history of frequent or prolonged corticosteroid use, hyperparathyroidism, rheumatoid arthritis, hyperthyroidism, celiaCsprue, previous stress fractures or overuse injuries as well as signs or symptoms of an eating disorder also should draw oneâs attention to the possibility of a reduced bone mass

Several metaboliChormones that influence bone formation (IGF-1, T3, leptin) as well as bone formation markers (serum Type I procollagen carboxyl and amino terminal propeptides, osteocalcin, bone specifiCalkaline phosphatase) and bone resorption markers (collagen degradation products, urine N-telopeptide, and serum C-telopeptide) can be followed to form an impression on the overall bone turnover status

The female athlete triad, first described in 1993, initially consisted of three interrelated conditions: eating disorders, amenorrhea, and osteoporosis. The definition has since been broadened to disordered eating, menstrual dysfunction, and low bone density (osteopenia or osteoporosis) to include all those at risk for the detrimental effects to bone

Literature regarding nonsteroidal anti-inflammatory drug (NSAID) use in stress fracture healing is lacking; however, there has been research into its risks associated with complete fractures and nonunion after surgery. Prostaglandins play a crucial role in bone metabolism and repair. Cyclooxygenase-2 (COX-2) products have been found to be essential to bone repair in animal studies. Animal studies have shown that NSAIDs including indomethacin, aspirin, ibuprofen, and COX-2 inhibitors cause delayed fracture healing that may or may not be reversible on cessationCorrect Answer: Pain relief with nonsteroidal anti-inflammatory drugs (NSAIDs)

Generally, it is best to increase training time and intensity by 150 nm) can stimulate phagocytosis in specialized cells such as macrophages. Once internalized, metal particles can induce cytotoxicity, chromosomal damage, and oxidative stress. The toxicity of particles is modified by passivation and particle size. These factors both influence the dissolution of metal from the surface, which may account for biological activity. Evidence of cell damage, such as irregular cell membranes and enlarged mitochondria, may be induced by the physical properties of the particles

The pattern of inflammation in the periprosthetiCtissue of loose metal-on-metal articulations is significantly different to that of metal-on-metal polyethylene articulations, and is characterized by perivascular infiltration of lymphocytes and the accumulation of plasma cells. Experimental data suggest that orthopediCmetals induce immunological effects that support a cell-mediated hypersensitivity response

The International Agency for Research on Cancer, which publishes information on the risks posed by chemicals on the development of human cancers, has classified Cr (VI) and Ni (II) as carcinogenic, metalliCNi and soluble Co as possibly carcinogenic, and metalliCCr, Cr (III) compounds and implanted orthopediCalloys as unclassifiable

Experimental animal studies suggest that several metals, including Cr, Co, Ni, V and Al, may induce development toxicity. For example, Cr (VI) exposure in male and/or female mice either before or during gestation can affect the number of implantations and viable fetuses resulting from conception. Many metals can also induce teratogeniCmalformations, including Cr, Ni, and V

The accumulation of Co in the myocardium can induce cardiomyopathy, which was particularly evident after the 1996 episode of âbeer-drinkersâ cardiomyopathy, during which Co was used as a foam-stabilizing agent in beer

Deposition of A1 in the bone occurs as a consequence of chroniCexposure and has been linked to osteomalacia, bone pain, pathological fractures, proximal myopathy, and the failure to respond to vitamin D therapy

Al, Co, and Ni can cause severe retinal degeneration at high-concentrations in experimental animals

Metal-induced skin reactions can include contact dermatitis, urticaria, and/or vasculitis. The incidence of dermal reactions and positive skin-patch testing to Co, Ni, and Cr in patients with total joint replacement with stable and loose prostheses increases by
15% and 50% respectively, above those of the general population

Metal-induced skin reactions can include contact dermatitis, urticaria ,and/or vasculitis. The incidence of dermal reactions and positive skin-patch testing to Co, Ni, and Cr in patients with total joint replacement with stable and loose prostheses increases by
15% and 50% respectively, above those of the general population

Hepatocellular necrosis often occurs in response to high levels of metal in the body, as observed after acute ingestion of Cr (VI) in humans

Cr is concentrated in the epithelial cells of the proximal renal tubules and can impair renal function, induce tubular necrosis, and cause marked interstitial changes in experimental animals and humans. Indicators of tubular dysfunction have been identified in human objects exposed to Cr (VI) through occupation. Al, Ni, and Co are all rapidly excreted by the kidney, hence renal toxicity tends to require significantly larger doses

Several neurological manifestations have been attributed to Al intoxication in humans, including memory loss, jerking, ataxia, and neurofibrillary degeneration. The development of some neuropathological conditions, including amyotrophiClateral sclerosis, Parkinsonian, dementia, dialysis encephalopathy, and senile plaques of Alzheimerâs disease, may be related to the accumulation of Al in the brain

A computed tomography scan provides important information in regard to the version of the glenoid, wear pattern, amount of wear, glenohumeral subluxation, as well as desired entry point

The most common reason for revision surgery among patients with rheumatoid arthritis is painful glenoid arthritis. The rate of revision for painful glenoid arthritis is higher than that for glenoid component loosening