Pediatric Musculoskeletal Disorders

A 7-year-old boy is brought to the pediatric orthopedics clinic by his parents due to a persistent limp favoring his left leg. The parents report that the limping began approximately 5 weeks ago and is particularly noticeable after he plays outside. He occasionally complains of a dull ache in his left anterior thigh, but he denies any knee or back pain. There is no history of recent trauma, falls, or upper respiratory tract infections. His temperature is 37.0°C (98.6°F), blood pressure is 98/62 mm Hg, and pulse is 84/min. On physical examination, the patient has an antalgic gait. The left hip demonstrates restricted internal rotation and limited abduction compared to the right hip. The circumference of the left thigh is 2 cm smaller than that of the right thigh. Laboratory evaluation reveals a leukocyte count of 6,800/mm³, an erythrocyte sedimentation rate of 9 mm/hr, and a C-reactive protein level of 0.3 mg/dL. Anteroposterior and frog-leg lateral radiographs of the pelvis show completely normal bony architecture, symmetric joint spaces, and no epiphyseal flattening. Which of the following is the most appropriate next step in the diagnostic workup or management of this patient?

A 12-year-old boy is brought to the clinic for a 4-week history of right-sided knee pain and a progressive limp. The pain is characterized as a dull ache that is exacerbated by walking and participating in sports. He has no history of trauma, falls, or fever. His medical history is significant for growth hormone deficiency, for which he has been receiving somatropin injections for the past 6 months. His body mass index is at the 60th percentile for his age. His temperature is 37.1°C (98.8°F), blood pressure is 110/70 mm Hg, and pulse is 78/min. On physical examination, there is no swelling, erythema, or localized tenderness over the right knee, and ligamentous testing is stable. Range of motion of the right knee is full and painless. When the patient walks, he exhibits an antalgic gait with the right foot pointing outward. During examination of the hips, passive flexion of the right hip results in obligate external rotation of the thigh. Internal rotation of the right hip is limited compared to the left. Which of the following is the most appropriate next step in management?

A 2-year-old girl is evaluated in the emergency department for refusal to move her right arm. Approximately three hours ago, she was holding hands with her older brother and suddenly tripped; the brother quickly pulled her up by the hand to prevent her from falling. Following this event, she began crying and has kept her right arm tucked against her torso. On physical examination, the patient's right elbow is held in slight flexion and the forearm is pronated. There is no visible ecchymosis, erythema, or localized edema. She exhibits marked resistance and distress upon attempted passive supination of the right forearm, but no focal tenderness is elicited over the clavicle, distal humerus, or wrist. Her vital signs are stable, including a temperature of $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$) and a heart rate of $110/\text{min}$. Laboratory testing shows a leukocyte count of $7,500/\text{mm}^3$, an erythrocyte sedimentation rate (ESR) of $8\text{ mm/hr}$, and a C-reactive protein (CRP) level of $2\text{ mg/L}$. Which of the following is the most appropriate next step in management?

Match each pediatric patient's clinical presentation with the most likely musculoskeletal diagnosis.

A 10-day-old male neonate is evaluated in the pediatric orthopedics clinic for bilateral foot abnormalities present since birth. The pregnancy was uncomplicated, and he was born at term via spontaneous vaginal delivery. On physical examination, both feet exhibit deep medial creases, plantar flexion of the ankles, inversion of the heels, and medial deviation of the forefeet. The deformities are rigid and cannot be passively manipulated into a neutral position. There are no dimples over the sacrum, and lower extremity reflexes are normal. The physician discusses the standard evidence-based, nonoperative management protocol with the parents. Arrange the following steps of the standard treatment protocol for this patient's condition in the correct chronological sequence.

Match each pediatric patient's clinical presentation with the most appropriate next step in management.

A $7$-year-old male child presents to the outpatient clinic accompanied by his mother due to an altered gait that began approximately $8$ weeks ago. The mother describes a progressive limp that worsens towards the end of the day. The child occasionally mentions mild aching in his left groin and distal anterior thigh. He has not had any recent infections, and there is no history of preceding trauma. Vital signs show a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), pulse of $84/\text{min}$, and blood pressure of $102/64\text{ mm Hg}$. On physical examination, the patient has a noticeable Trendelenburg gait. Inspection reveals $1\text{ cm}$ of muscle atrophy in the left quadriceps compared to the right. When the patient is supine, the left hip exhibits limited abduction and restricted internal rotation. Examination of the left knee reveals no swelling, erythema, or pain with movement. Laboratory analysis demonstrates a leukocyte count of $7,200/\text{mm}^3$, an erythrocyte sedimentation rate of $10\text{ mm/h}$, and a C-reactive protein of $2.0\text{ mg/L}$. Which of the following is the most appropriate initial step in the evaluation of this patient?

A $14$-year-old adolescent male is brought to the emergency department immediately following a basketball game due to severe, acute right knee pain. He reports that while forcefully contracting his quadriceps to jump for a rebound, he felt a loud "pop" in his knee and immediately collapsed to the floor. He has been unable to bear weight since the injury. The patient has a $6$-month history of localized pain over the right anterior proximal tibia that worsens with running, which his pediatrician previously diagnosed as a traction apophysitis. Vital signs are within normal limits. On physical examination, the right knee has a large, tense effusion. The patient is completely unable to perform a straight leg raise or actively extend the right knee against gravity. A distinct, palpable defect is noted just inferior to the patella, and the tibial tuberosity is exquisitely tender and appears proximally migrated. Radiographs demonstrate a displaced fracture fragment arising from the anterior proximal tibia. Which of the following is the most appropriate next step in the management of this patient?

Match each pediatric patient's clinical presentation with the statement that best describes the precise underlying pathophysiologic mechanism of their condition.

A 5-year-old boy is brought to the pediatrician by his parents because he has been limping since yesterday morning. The parents report that he had a mild upper respiratory tract infection about one week ago, which resolved without treatment. He refuses to bear full weight on his right leg but is able to walk with a noticeable limp. His temperature is 37.4°C (99.3°F), blood pressure is 95/60 mm Hg, pulse is 98/min, and respirations are 20/min. Physical examination shows no erythema or swelling of the lower extremities. There is full range of motion of the right knee and ankle. However, internal rotation and abduction of the right hip elicit discomfort. Laboratory studies show:

Leukocyte count: $7,500/\text{mm}^3$
Erythrocyte sedimentation rate: $15 \text{ mm/h}$
C-reactive protein: $0.5 \text{ mg/dL}$

Radiographs of the right hip and pelvis are unremarkable. Which of the following is the most appropriate next step in management for this patient?

A 4-year-old boy is brought to the emergency department by his parents because he has been refusing to walk since he woke up this morning. The parents note that he complains of pain in his right anterior thigh and knee. He had a mild upper respiratory tract infection two weeks ago but has otherwise been healthy. His temperature is $38.7^\circ\text{C}$ ($101.7^\circ\text{F}$), blood pressure is $90/60\text{ mm Hg}$, pulse is $118/\text{min}$, and respirations are $22/\text{min}$. On physical examination, the child appears uncomfortable and refuses to stand or bear any weight on his right leg. The right hip is held in slight flexion, abduction, and external rotation. There is no visible erythema or swelling of the hip, thigh, or knee. Range of motion of the right knee is full and painless, but any attempt to internally rotate the right hip elicits severe pain and crying. Laboratory studies show:

Which of the following is the most appropriate next step in the management of this patient?

A $14$-year-old male is brought to the clinic due to a $4$-week history of right knee pain and an altering gait. He has no history of trauma, fever, or recent illnesses. His weight is at the $98^{\text{th}}$ percentile for his age. Vital signs show a temperature of $37.1^\circ\text{C}$ ($98.8^\circ\text{F}$), heart rate of $78\text{/min}$, and blood pressure of $118/76\text{ mm Hg}$. Physical examination of the right knee reveals no effusion, joint line tenderness, or ligamentous laxity. During the examination of the lower extremities in the supine position, passive flexion of the right hip results in obligatory external rotation of the thigh. Laboratory studies show a leukocyte count of $6,800/\text{mm}^3$, an erythrocyte sedimentation rate of $8\text{ mm/h}$, and a C-reactive protein level of $0.3\text{ mg/dL}$. Which of the following is the most appropriate next step in management?

A 4-year-old boy is brought to the clinic by his parents due to a right-sided limp that began this morning. He refuses to bear weight on his right leg. His parents report that he had a mild upper respiratory tract infection one week ago that resolved without treatment. He has no history of trauma. Temperature is 37.1°C (98.8°F), blood pressure is 100/60 mm Hg, pulse is 98/min, and respirations are 20/min. Physical examination shows a well-appearing, playful boy. There is pain with internal rotation and abduction of the right hip, but no visible erythema, swelling, or warmth over the joint. Laboratory studies show:

Leukocyte count: 9,000/mm³
Erythrocyte sedimentation rate (ESR): 15 mm/h
C-reactive protein (CRP): 5 mg/L

Which of the following is the most appropriate next step in management?

A 13-year-old boy is brought to the clinic by his mother due to a 3-week history of right knee pain and a progressive limp. He describes the pain as a dull, constant ache that worsens with physical activity. He denies any recent trauma, fever, chills, or weight loss. His medical history is unremarkable. He is at the 95th percentile for weight and 50th percentile for height. Vital signs are within normal limits. On physical examination, the right knee has no effusion, erythema, warmth, or tenderness to palpation. Ligamentous and meniscal testing of the knee is unremarkable. When asked to walk, the patient demonstrates an antalgic gait. During range of motion testing of the right lower extremity, passive flexion of the right hip results in obligatory external rotation of the thigh. Which of the following is the most appropriate next step in management?

An 8-year-old boy is brought to the clinic by his parents due to a 1-month history of right knee pain and a worsening right-sided limp. He has no history of trauma, fever, or recent illnesses. His parents note that he has been growing at a slower rate than his peers, falling from the 50th percentile to the 5th percentile for height over the past two years. His current weight is at the 30th percentile. The parents also report that he has been more fatigued lately and has developed constipation. Vital signs are within normal limits. On physical examination, the right knee has no effusion, erythema, or tenderness; range of motion is full and painless. Evaluation of the right hip reveals limited internal rotation. When the right hip is passively flexed, the thigh obligatorily rotates externally. Radiographs of the right hip show widening of the proximal femoral physis and posterior displacement of the femoral head relative to the femoral neck. Which of the following is the most appropriate next step in the management of this patient?

A 4-year-old boy presents to the emergency department with acute-onset limping and an inability to bear weight on his right lower extremity. His parents report that he developed a high fever earlier today. He was previously healthy and has no recent history of trauma. Temperature is 39.1°C (102.4°F), blood pressure is 100/65 mm Hg, and pulse is 125/min. On examination, the patient is distressed. The right hip is held in a position of flexion, abduction, and external rotation. Passive range of motion of the right hip elicits severe pain. There is no overlying erythema or swelling. Arrange the following steps in the most appropriate chronological order for the evaluation and management of this patient's condition.

A 5-year-old boy is brought to the emergency department by his parents due to a sudden onset of right hip pain and a complete refusal to bear weight on his right leg since this morning. His temperature is 38.9°C (102.0°F). On physical examination, he appears uncomfortable and holds his right hip in a flexed, abducted, and externally rotated position. Any attempt at passive range of motion of the right hip elicits severe crying and guarding. The clinical suspicion for septic arthritis is high. Arrange the following diagnostic and therapeutic steps in the most appropriate sequential order for the management of this patient.

During a well-child visit, the parents of a $6$-year-old boy express concern about a change in their son's walking pattern. They report that for the past $8$ weeks, he has been favoring his right leg, especially after running or playing at the park. When asked if he has any pain, the child points to his right anterior thigh and the area just above his kneecap. The parents have not noticed any fevers, rashes, or recent illnesses. He has met all developmental milestones and has no significant past medical history. His temperature is $37.0^\circ\text{C}$ ($98.6^\circ\text{F}$), heart rate is $90/\text{min}$, and blood pressure is $98/60\text{ mm Hg}$. Physical examination reveals a well-appearing boy who walks with a right-sided antalgic gait and a noticeable drop of the left hemipelvis during the stance phase on his right leg. There is no visible swelling or erythema over the right knee or hip. Palpation of the knee elicits no tenderness, and knee range of motion is full and painless. However, placing the right hip in internal rotation and abduction provokes mild discomfort and is noticeably restricted compared to the left side. Blood tests reveal an erythrocyte sedimentation rate of $9\text{ mm/h}$ and a leukocyte count of $6,800/\text{mm}^3$. Which of the following is the most appropriate next step in the management of this patient?

An 18-month-old girl is brought to the pediatric clinic by her parents who have noticed she has been walking with a limp for the past 8 weeks. The parents report that her limp is most noticeable when she first wakes up in the morning or after naps, but her gait appears almost normal by the afternoon. She has no history of trauma, tick bites, or recent travel. She has not had any fevers, rashes, or weight loss. Vital signs are within normal limits. On physical examination, the right knee appears moderately swollen and is slightly warm compared to the left, but there is no overlying erythema. She resists full extension of the right knee but does not cry during the examination. Laboratory studies show a normal complete blood count, an erythrocyte sedimentation rate of 12 mm/h, and a C-reactive protein level of 0.3 mg/dL (normal < 1.0 mg/dL). Antinuclear antibody (ANA) testing is positive at a titer of 1:640, while rheumatoid factor is negative. Which of the following is the most appropriate next step in the management of this patient?

A 5-year-old boy is brought to the emergency department with a 1-day history of severe right hip pain and fever. He refuses to walk or bear any weight on his right leg. His temperature is 38.9°C (102.0°F). On physical examination, he appears irritable. His right hip is held rigidly in flexion, abduction, and external rotation; any attempt at passive range of motion elicits severe pain and crying. You suspect a severe acute joint infection. Arrange the following steps in the most appropriate sequential order for the standard diagnostic evaluation and management of this patient's condition.