Book contents
- Frontmatter
- Contents
- List of contributors
- Foreword
- Preface
- Section 1 Shoulder
- Section 2 Arm
- Section 3 Elbow
- Section 4 Forearm
- Section 5 Wrist
- Section 6 Hand
- Section 7 Hip and Pelvis
- Case 45 Femoroacetabular impingement: cam- versus pincer-type
- Case 46 Snapping hip
- Case 47 Labral tear versus cleft versus labral recess
- Case 48 Transient bone marrow edema of the hip (transient osteoporosis) versus osteonecrosis
- Case 49 Hip fractures in the elderly
- Case 50 Insufficiency fractures of the pelvis
- Case 51 Mild-to-moderate acetabular maldevelopment in the adult hip
- Case 52 Calcific tendinitis of the hip
- Case 53 Hip arthroplasty: periprosthetic fracture in the femur
- Section 8 Thigh
- Section 9 Leg
- Section 10 Ankle
- Section 11 Foot
- Section 12 Tumors/Miscellaneous
- Index
- References
Case 45 - Femoroacetabular impingement: cam- versus pincer-type
from Section 7 - Hip and Pelvis
Published online by Cambridge University Press: 05 July 2013
- Frontmatter
- Contents
- List of contributors
- Foreword
- Preface
- Section 1 Shoulder
- Section 2 Arm
- Section 3 Elbow
- Section 4 Forearm
- Section 5 Wrist
- Section 6 Hand
- Section 7 Hip and Pelvis
- Case 45 Femoroacetabular impingement: cam- versus pincer-type
- Case 46 Snapping hip
- Case 47 Labral tear versus cleft versus labral recess
- Case 48 Transient bone marrow edema of the hip (transient osteoporosis) versus osteonecrosis
- Case 49 Hip fractures in the elderly
- Case 50 Insufficiency fractures of the pelvis
- Case 51 Mild-to-moderate acetabular maldevelopment in the adult hip
- Case 52 Calcific tendinitis of the hip
- Case 53 Hip arthroplasty: periprosthetic fracture in the femur
- Section 8 Thigh
- Section 9 Leg
- Section 10 Ankle
- Section 11 Foot
- Section 12 Tumors/Miscellaneous
- Index
- References
Summary
Imaging description
Femoroacetabular impingement (FAI) is a common cause of hip pain and eventual osteoarthritis of the hip. It is screened for using an AP radiograph of the pelvis. The radiograph must be aligned as perfectly as possible with the coccyx centered at the symphysis pubis so that no rotation of the pelvis is present. Femoroacetabular impingement is broken down into three major categories: cam-type, pincer-type, and mixed type. Patients with the mixed type of FAI have coexistence of both the cam- and pincer-type. The cam-type can be thought of as abnormal formation/development of the femoral head/neck junction. This can be seen as an osseous bump or as a pistol grip deformity (loss of normal concavity) at the femoral head/neck junction (Figure 45.1). The pincer-type of FAI is abnormal coverage or positioning of the acetabulum. The pincer-type can be diagnosed on radiographs by the presence of coxa profunda, acetabular protrusion, or acetabular retroversion. Coxa profunda and acetabular protrusion are diagnosed radiographically by abnormal positioning of the femoral head and acetabulum relative to the ilioischial line (Figure 45.2). Acetabular retroversion can be diagnosed by presence of the cross-over sign, posterior acetabular wall sign, or the prominent ischial spine sign (Figure 45.3).
Importance
Femoroacetabular impingement is important to recognize in patients with hip pain as treatment of this disease has the best outcome if it is recognized early so that osteoarthritis has not yet developed. Development of osteoarthritis is felt to be the eventual outcome in symptomatic FAI patients if the disease goes untreated. The basic pathology is abnormal abutment of the femoral head/neck junction on the acetabular rim during flexion. This abutment causes labral and cartilage damage at the hip leading to incongruity of the hip joint. Continued usage of an incongruous joint leads to the development of osteoarthritis.
- Type
- Chapter
- Information
- Pearls and Pitfalls in Musculoskeletal ImagingVariants and Other Difficult Diagnoses, pp. 93 - 95Publisher: Cambridge University PressPrint publication year: 2013