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AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS
Your Source for Lifelong Orthopaedic Learning
Pediatric
Orthopedic
Answer Book
, 2025 Pediatric Orthopaedic Examination Answer Book · 7
Figure 1a Figure 1b
Question 1
A 5-year-old boy has had a limp for the past 4 weeks with intermittent pain at the foot. He remains
normally active and has no history of trauma. He has no fevers, rashes, or swelling. Examination reveals
tenderness at the mid-dorsum of the foot medially. Radiographs are seen in Figures 1a and l b. Treatment
should include which of the following?
1. MRl of the foot with gadolinium
2. Open biopsy of the lesion
3. Needle aspiration and culture, followed by antibiotic treatment
4. Observation or an orthotic arch support
5. Steroid injection of the lesion
PREFERRED RESPONSE: 4
DISCUSSION: Osteochondrosis of the tarsal navicular is most commonly identified between the ages of
2 and 9 years. The condition is benign and self limited in nature. In patients with severe pain, a period
of casting may be warranted, but otherwise management usually consists of observation or a supportive
orthotic.
REFERENCES: DiGiovanni CW, Patel A, Calfee R, et al: Osteonecrosis in the foot. JAm Acad Orthop
Surg 2007; 15 :208-217.
Williams GA, Cowell HR: Kohler's disease of the tarsal navicular. Clin Orthop Relat Res 198 1; 158:53-
58.
,8 American Academy of Orthopaedic Surgeons
•
Figure 2
Question 2
A 3 -year-old girl has had pain and swelling in her left thigh for the past 3 weeks. Her mother states she
has had a temperature as high as 10 0.4 degrees F (38 degrees C) and a weight loss of 5 pounds. A CBC
shows a WBC count of 11 ,000/mm3 , an erythroc yte sedimentation rate of 1 3 mmlh, and a C-reactive
protein of 0 .3 . A radiograph is shown in Figure What is the next step in management?
1. Biopsy and culture of the lesion
2. MRI of the left femur
3. IV antibiotics for 6 weeks
4. Incision and drainage of the left femur
5. Repeat radiograph in 3 months
P REFERRED RE SPON SE: 2
DI SCU SSION: The history and laboratory studies indicate that this is not an infection. A lesion in this
location and in this age group is likely a Ewing's sarcoma. The presentation is usually a painful mass.
About 20% of patients have a fever. The radiograph shows a typical mottled, permeative lesion with
periosteal reaction. An MRIscan should be obtained to further evaluate the soft-tissue mass. Staging of
the lesion should take place before biopsy, which should be done by the surgeon who would be perfo rming
the next stage of surgical treatment, ideally an orthopaedic oncologist.
REFE RENCE S: Gibbs CP Jr, Weber K , Scarborough MT: Malignant bone tumors . Instr Course Lect
2002;5 1 :4 1 3-428.
Meyer IS, Nadel HR, Marina N, et al: Imaging guidelines for children with Ewing s arcoma and
osteosarcoma: A report from the Children's Oncology Group Bone Tumor Committee. Pediatr Blood
Cancer 2008;5 1 : 1 6 3 - 1 70 .
, 2025 Pediatric Orthopaedic Examination Answer Book · 9
Figure 3
Question 3
A 9-year-old girl has had bilateral knee and leg pain for the past 2 years. The family has noted increasing
deformity in both lower extremities. She is less than the fifth percentile for height. Examination reveals
bilateral femoral bowing, mild medial-lateral laxity of the knees, and the deformities shown in the
radiograph seen in Figure 3. What is the most likely diagnosis?
1. Renal osteodystrophy
2. Diastrophic dysplasia
3. Metaphyseal dysplasia
4. Osteogenesis imperfecta
5. Fibrous dysplasia
PREFERRED RESPONSE: 1
DISCUSSION: The widening, bowing, and cupping of the physes indicate some form of metabolic
bone disease; therefore, the most likely diagnosis is renal osteodystrophy. The age of onset makes
X- linked hypophosphatemic rickets less likely. The ground glass lesions and widening of the medullary
canal characteristic of fibrous dysplasia are not present. There are no fractures creating the deformities
indicating osteogenesis imperfecta. There is an asymmetry of the deformities that makes diastrophic
dysplasia less likely.
REFERENCES: Goldberg MJ, Yassir W, Sadeghi-Nejad A: Clinical analysis of short stature. J Pediatr
Orthop 2002;22:690-696.
Parmar VS, Stanitski DF, Stanitski CL: Interpretation of radiographs in a pediatric limb deformity
practice: Do radiologists contribute? J Pediatr Orthop 1999; 19:732-734.
AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS
Your Source for Lifelong Orthopaedic Learning
Pediatric
Orthopedic
Answer Book
, 2025 Pediatric Orthopaedic Examination Answer Book · 7
Figure 1a Figure 1b
Question 1
A 5-year-old boy has had a limp for the past 4 weeks with intermittent pain at the foot. He remains
normally active and has no history of trauma. He has no fevers, rashes, or swelling. Examination reveals
tenderness at the mid-dorsum of the foot medially. Radiographs are seen in Figures 1a and l b. Treatment
should include which of the following?
1. MRl of the foot with gadolinium
2. Open biopsy of the lesion
3. Needle aspiration and culture, followed by antibiotic treatment
4. Observation or an orthotic arch support
5. Steroid injection of the lesion
PREFERRED RESPONSE: 4
DISCUSSION: Osteochondrosis of the tarsal navicular is most commonly identified between the ages of
2 and 9 years. The condition is benign and self limited in nature. In patients with severe pain, a period
of casting may be warranted, but otherwise management usually consists of observation or a supportive
orthotic.
REFERENCES: DiGiovanni CW, Patel A, Calfee R, et al: Osteonecrosis in the foot. JAm Acad Orthop
Surg 2007; 15 :208-217.
Williams GA, Cowell HR: Kohler's disease of the tarsal navicular. Clin Orthop Relat Res 198 1; 158:53-
58.
,8 American Academy of Orthopaedic Surgeons
•
Figure 2
Question 2
A 3 -year-old girl has had pain and swelling in her left thigh for the past 3 weeks. Her mother states she
has had a temperature as high as 10 0.4 degrees F (38 degrees C) and a weight loss of 5 pounds. A CBC
shows a WBC count of 11 ,000/mm3 , an erythroc yte sedimentation rate of 1 3 mmlh, and a C-reactive
protein of 0 .3 . A radiograph is shown in Figure What is the next step in management?
1. Biopsy and culture of the lesion
2. MRI of the left femur
3. IV antibiotics for 6 weeks
4. Incision and drainage of the left femur
5. Repeat radiograph in 3 months
P REFERRED RE SPON SE: 2
DI SCU SSION: The history and laboratory studies indicate that this is not an infection. A lesion in this
location and in this age group is likely a Ewing's sarcoma. The presentation is usually a painful mass.
About 20% of patients have a fever. The radiograph shows a typical mottled, permeative lesion with
periosteal reaction. An MRIscan should be obtained to further evaluate the soft-tissue mass. Staging of
the lesion should take place before biopsy, which should be done by the surgeon who would be perfo rming
the next stage of surgical treatment, ideally an orthopaedic oncologist.
REFE RENCE S: Gibbs CP Jr, Weber K , Scarborough MT: Malignant bone tumors . Instr Course Lect
2002;5 1 :4 1 3-428.
Meyer IS, Nadel HR, Marina N, et al: Imaging guidelines for children with Ewing s arcoma and
osteosarcoma: A report from the Children's Oncology Group Bone Tumor Committee. Pediatr Blood
Cancer 2008;5 1 : 1 6 3 - 1 70 .
, 2025 Pediatric Orthopaedic Examination Answer Book · 9
Figure 3
Question 3
A 9-year-old girl has had bilateral knee and leg pain for the past 2 years. The family has noted increasing
deformity in both lower extremities. She is less than the fifth percentile for height. Examination reveals
bilateral femoral bowing, mild medial-lateral laxity of the knees, and the deformities shown in the
radiograph seen in Figure 3. What is the most likely diagnosis?
1. Renal osteodystrophy
2. Diastrophic dysplasia
3. Metaphyseal dysplasia
4. Osteogenesis imperfecta
5. Fibrous dysplasia
PREFERRED RESPONSE: 1
DISCUSSION: The widening, bowing, and cupping of the physes indicate some form of metabolic
bone disease; therefore, the most likely diagnosis is renal osteodystrophy. The age of onset makes
X- linked hypophosphatemic rickets less likely. The ground glass lesions and widening of the medullary
canal characteristic of fibrous dysplasia are not present. There are no fractures creating the deformities
indicating osteogenesis imperfecta. There is an asymmetry of the deformities that makes diastrophic
dysplasia less likely.
REFERENCES: Goldberg MJ, Yassir W, Sadeghi-Nejad A: Clinical analysis of short stature. J Pediatr
Orthop 2002;22:690-696.
Parmar VS, Stanitski DF, Stanitski CL: Interpretation of radiographs in a pediatric limb deformity
practice: Do radiologists contribute? J Pediatr Orthop 1999; 19:732-734.
