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KEY FACTS
Terminology
Imaging
Top Differential Diagnoses
Pathology
Clinical Issues
Diagnostic Checklist
TERMINOLOGY
Synonyms
- Subchondral insufficiency fracture (SIF) of knee, insufficiency fracture, stress fracture of knee, Ahlbäck disease
Definitions
- Incomplete atraumatic medullary fracture of subchondral bone of distal femur or proximal tibia
- Not optimal term for traumatic small nondisplaced fracture: probably better termed "subcortical fracture" or "nondisplaced osteochondral fracture"
- Spontaneous osteonecrosis of knee (SONK): former term used for end-stage collapse of SIF
- Term was created when there was no understanding of MR findings, underlying pathology, or cause
- This concept has been abandoned
- "SONK" should not be used in radiology reports
- True osteonecrosis (ON) does occur in femoral condyles; resembles that of femoral head
IMAGING
General Features
Radiographic Findings
CT Findings
MR Findings
Nuclear Medicine Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Gross Pathologic & Surgical Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Image Interpretation Pearls
Reporting Tips
Selected References
- Gorbachova T et al: Osteochondral lesions of the knee: differentiating the most common entities at MRI. Radiographics. 38(5):1478-95, 2018
- Matcuk GR Jr et al: Stress fractures: pathophysiology, clinical presentation, imaging features, and treatment options. Emerg Radiol. 23(4):365-75, 2016
- Viana SL et al: MRI of subchondral fractures: a review. Skeletal Radiol. 43(11):1515-27, 2014
- Cetik O et al: Risk of osteonecrosis of the femoral condyle after arthroscopic chondroplasty using radiofrequency: a prospective clinical series. Knee Surg Sports Traumatol Arthrosc. 17(1):24-9, 2009
- Fotiadou A et al: Acute nontraumatic adult knee pain: the role of MR imaging. Radiol Med. 114(3):437-47, 2009
- Roemer FW et al: MRI-detected subchondral bone marrow signal alterations of the knee joint: terminology, imaging appearance, relevance and radiological differential diagnosis. Osteoarthritis Cartilage. 17(9):1115-31, 2009
- Kattapuram TM et al: Spontaneous osteonecrosis of the knee. Eur J Radiol. 67(1):42-8, 2008
- MacDessi SJ et al: Subchondral fracture following arthroscopic knee surgery. A series of eight cases. J Bone Joint Surg Am. 90(5):1007-12, 2008
- Takeda M et al: Spontaneous osteonecrosis of the knee: histopathological differences between early and progressive cases. J Bone Joint Surg Br. 90(3):324-9, 2008
- Pape D et al: Postarthroscopic osteonecrosis of the knee. Arthroscopy. 23(4):428-38, 2007
- Yates PJ et al: Early MRI diagnosis and non-surgical management of spontaneous osteonecrosis of the knee. Knee. 14(2):112-6, 2007
- Muscolo DL et al: Medial meniscal tears and spontaneous osteonecrosis of the knee. Arthroscopy. 22(4):457-60, 2006
- Kidwai AS et al: Radiologic case study. Spontaneous osteonecrosis of the knee reclassified as insufficiency fracture. Orthopedics. 28(3):236, 333-6, 2005
- Lecouvet FE et al: MR imaging of epiphyseal lesions of the knee: current concepts, challenges, and controversies. Radiol Clin North Am. 43(4):655-72, vii-viii, 2005
- Ramnath RR et al: MR appearance of SONK-like subchondral abnormalities in the adult knee: SONK redefined. Skeletal Radiol. 33(10):575-81, 2004
- Yamamoto T et al: Spontaneous osteonecrosis of the knee: the result of subchondral insufficiency fracture. J Bone Joint Surg Am. 82(6):858-66, 2000
- Yamamoto T et al: Subchondral insufficiency fracture of the femoral head and medial femoral condyle. Skeletal Radiol. 29(1):40-4, 2000
- Ecker ML et al: Spontaneous osteonecrosis of the knee. J Am Acad Orthop Surg. 2(3):173-8, 1994
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References
Tables
Tables
KEY FACTS
Terminology
Imaging
Top Differential Diagnoses
Pathology
Clinical Issues
Diagnostic Checklist
TERMINOLOGY
Synonyms
- Subchondral insufficiency fracture (SIF) of knee, insufficiency fracture, stress fracture of knee, Ahlbäck disease
Definitions
- Incomplete atraumatic medullary fracture of subchondral bone of distal femur or proximal tibia
- Not optimal term for traumatic small nondisplaced fracture: probably better termed "subcortical fracture" or "nondisplaced osteochondral fracture"
- Spontaneous osteonecrosis of knee (SONK): former term used for end-stage collapse of SIF
- Term was created when there was no understanding of MR findings, underlying pathology, or cause
- This concept has been abandoned
- "SONK" should not be used in radiology reports
- True osteonecrosis (ON) does occur in femoral condyles; resembles that of femoral head
IMAGING
General Features
Radiographic Findings
CT Findings
MR Findings
Nuclear Medicine Findings
Imaging Recommendations
DIFFERENTIAL DIAGNOSIS
PATHOLOGY
General Features
Gross Pathologic & Surgical Features
CLINICAL ISSUES
Presentation
Demographics
Natural History & Prognosis
Treatment
DIAGNOSTIC CHECKLIST
Consider
Image Interpretation Pearls
Reporting Tips
Selected References
- Gorbachova T et al: Osteochondral lesions of the knee: differentiating the most common entities at MRI. Radiographics. 38(5):1478-95, 2018
- Matcuk GR Jr et al: Stress fractures: pathophysiology, clinical presentation, imaging features, and treatment options. Emerg Radiol. 23(4):365-75, 2016
- Viana SL et al: MRI of subchondral fractures: a review. Skeletal Radiol. 43(11):1515-27, 2014
- Cetik O et al: Risk of osteonecrosis of the femoral condyle after arthroscopic chondroplasty using radiofrequency: a prospective clinical series. Knee Surg Sports Traumatol Arthrosc. 17(1):24-9, 2009
- Fotiadou A et al: Acute nontraumatic adult knee pain: the role of MR imaging. Radiol Med. 114(3):437-47, 2009
- Roemer FW et al: MRI-detected subchondral bone marrow signal alterations of the knee joint: terminology, imaging appearance, relevance and radiological differential diagnosis. Osteoarthritis Cartilage. 17(9):1115-31, 2009
- Kattapuram TM et al: Spontaneous osteonecrosis of the knee. Eur J Radiol. 67(1):42-8, 2008
- MacDessi SJ et al: Subchondral fracture following arthroscopic knee surgery. A series of eight cases. J Bone Joint Surg Am. 90(5):1007-12, 2008
- Takeda M et al: Spontaneous osteonecrosis of the knee: histopathological differences between early and progressive cases. J Bone Joint Surg Br. 90(3):324-9, 2008
- Pape D et al: Postarthroscopic osteonecrosis of the knee. Arthroscopy. 23(4):428-38, 2007
- Yates PJ et al: Early MRI diagnosis and non-surgical management of spontaneous osteonecrosis of the knee. Knee. 14(2):112-6, 2007
- Muscolo DL et al: Medial meniscal tears and spontaneous osteonecrosis of the knee. Arthroscopy. 22(4):457-60, 2006
- Kidwai AS et al: Radiologic case study. Spontaneous osteonecrosis of the knee reclassified as insufficiency fracture. Orthopedics. 28(3):236, 333-6, 2005
- Lecouvet FE et al: MR imaging of epiphyseal lesions of the knee: current concepts, challenges, and controversies. Radiol Clin North Am. 43(4):655-72, vii-viii, 2005
- Ramnath RR et al: MR appearance of SONK-like subchondral abnormalities in the adult knee: SONK redefined. Skeletal Radiol. 33(10):575-81, 2004
- Yamamoto T et al: Spontaneous osteonecrosis of the knee: the result of subchondral insufficiency fracture. J Bone Joint Surg Am. 82(6):858-66, 2000
- Yamamoto T et al: Subchondral insufficiency fracture of the femoral head and medial femoral condyle. Skeletal Radiol. 29(1):40-4, 2000
- Ecker ML et al: Spontaneous osteonecrosis of the knee. J Am Acad Orthop Surg. 2(3):173-8, 1994
