Osteoarthritis generally presents as asymmetrical joint stiffness and pain, often with bony protuberances (osteophytes) that are either palpable or visible on imaging. Symmetrical joint involvement is more typical in rheumatoid arthritis. Joints will present with signs of inflammation: redness, heat, pain, and swelling, due to the inflammatory nature of this condition.

Osteoarthritis generally presents as asymmetrical joint stiffness and pain, often with bony protuberances (osteophytes) that are either palpable or visible on imaging. Symmetrical joint involvement is more typical in rheumatoid arthritis. Joints will present with signs of inflammation: redness, heat, pain, and swelling, due to the inflammatory nature of this condition.

The correct answer is "compartment syndrome." Compartment syndrome is a surgical emergency in which an injury results in hemorrhage or swelling in an enclosed space that causes dangerously high pressures to build within the enclosed space, resulting in compromised bloodflow to the muscles and nerves within and distal to the space. The symptoms include a cool, pale, pulseless extremity that may also experience paresthesias, and that is visibly swollen and tense. In this case, the patient's right arm exhibits all of these characteristics, and this presentation is highly consistent with compartment syndrome.

The other choices are incorrect. Vasculitis and lupus are both autoimmune conditions that may result in limb swelling, but would be unlikely causes of this patient's presentation, especially in the setting of a recent local trauma to the affected limb. Fat embolism would not account for the patient's constellation of symptoms.There is no evidence of limb necrosis at this stage of the patient's injury. Should the compartment syndrome not be addressed and vascular flow remain compromised by persistently high pressures, then limb ischemia and consequent necrosis could be a downstream effect.

The correct answer is "compartment syndrome." Compartment syndrome is a surgical emergency in which an injury results in hemorrhage or swelling in an enclosed space that causes dangerously high pressures to build within the enclosed space, resulting in compromised bloodflow to the muscles and nerves within and distal to the space. The symptoms include a cool, pale, pulseless extremity that may also experience paresthesias, and that is visibly swollen and tense. In this case, the patient's right arm exhibits all of these characteristics, and this presentation is highly consistent with compartment syndrome.

The other choices are incorrect. Vasculitis and lupus are both autoimmune conditions that may result in limb swelling, but would be unlikely causes of this patient's presentation, especially in the setting of a recent local trauma to the affected limb. Fat embolism would not account for the patient's constellation of symptoms.There is no evidence of limb necrosis at this stage of the patient's injury. Should the compartment syndrome not be addressed and vascular flow remain compromised by persistently high pressures, then limb ischemia and consequent necrosis could be a downstream effect.

Osgood-Schlatter syndrome of irritation of the patellar ligament at the tibial tuberosity, characterized by painful lumps just below the knee, most often seen in young adolescents. Risk factors may include overzealous exercise but it's ultimately thought to be caused by adolescent bone growth. Osteosarcoma, the most common bone cancer in adolescent populations, can present with pain and a lump or frank swelling. This is caused by actual tumor growth, not by any ligamentous issue. Osteosarcoma does present frequently in the knee, and must be ruled out before a diagnosis of Osgood-Schlatter disease is made. Slipped capital femoral epiphysis causes pain and reduced movement in the hip, rather than the knee. Osteomalacia is a general softening of the bones caused by a deficiency in vitamin D.

Osgood-Schlatter syndrome of irritation of the patellar ligament at the tibial tuberosity, characterized by painful lumps just below the knee, most often seen in young adolescents. Risk factors may include overzealous exercise but it's ultimately thought to be caused by adolescent bone growth. Osteosarcoma, the most common bone cancer in adolescent populations, can present with pain and a lump or frank swelling. This is caused by actual tumor growth, not by any ligamentous issue. Osteosarcoma does present frequently in the knee, and must be ruled out before a diagnosis of Osgood-Schlatter disease is made. Slipped capital femoral epiphysis causes pain and reduced movement in the hip, rather than the knee. Osteomalacia is a general softening of the bones caused by a deficiency in vitamin D.

Patellofemoral syndrome presents as pain in the front of the knee, sometimes caused by wearing down, roughening, or softening of the cartilage under the kneecap. Osgood-Schlatter disease is a syndrome of irritation of the patellar ligament at the tibial tuberosity, characterized by painful lumps just below the knee, most often seen in young adolescents. Legg-Calvé-Perthes syndrome is due to disruption of blood flow to the femoral head, leading to avascular necrosis. Congenital scoliosis is a spinal deformity characterized by the curving of the spine at an angle greater than 10 degrees on radiography.

Patellofemoral syndrome presents as pain in the front of the knee, sometimes caused by wearing down, roughening, or softening of the cartilage under the kneecap. Osgood-Schlatter disease is a syndrome of irritation of the patellar ligament at the tibial tuberosity, characterized by painful lumps just below the knee, most often seen in young adolescents. Legg-Calvé-Perthes syndrome is due to disruption of blood flow to the femoral head, leading to avascular necrosis. Congenital scoliosis is a spinal deformity characterized by the curving of the spine at an angle greater than 10 degrees on radiography.

Polymyalgia rheumatica is an inflammatory musculoskeletal condition that presents with pain or stiffness, usually in the neck, shoulders, and hips. Amyotrophic lateral sclerosis (ALS) is a genetic disorder of muscle wasting and neuronal death. Symptoms include progressive muscular weakness, leading to paralysis and death. Guillain–Barré syndrome is a rapid-onset condition of reversible muscle paralysis and weakness following infection, most commonly C ampylobacter jejuni. Myositis is a general term for inflammation of the muscles, and can be due to various causes.

Polymyalgia rheumatica is an inflammatory musculoskeletal condition that presents with pain or stiffness, usually in the neck, shoulders, and hips. Amyotrophic lateral sclerosis (ALS) is a genetic disorder of muscle wasting and neuronal death. Symptoms include progressive muscular weakness, leading to paralysis and death. Guillain–Barré syndrome is a rapid-onset condition of reversible muscle paralysis and weakness following infection, most commonly C ampylobacter jejuni. Myositis is a general term for inflammation of the muscles, and can be due to various causes.