Low Positive Predictive Value of Bone Scan to Predict Impending Complete Fracture among Incomplete Atypical Femoral Fracture.
10.3346/jkms.2018.33.e157
- Author:
Young Kyun LEE
1
;
You Jin LEE
;
Na Kyoung LEE
;
Jae Hwi NHO
;
Kyung Hoi KOO
Author Information
1. Department of Orthopaedic Surgery, Seoul National University Bundang Hospital, Seongnam, Korea.
- Publication Type:Original Article
- Keywords:
Atypical Femoral Fracture;
Bone Scan, Prophylactic Fixation;
Impending Fracture;
Femur
- MeSH:
Diagnosis;
Femoral Fractures*;
Femur;
Humans;
Sensitivity and Specificity
- From:Journal of Korean Medical Science
2018;33(22):e157-
- CountryRepublic of Korea
- Language:English
-
Abstract:
BACKGROUND: Although bone scan might be useful to detect incomplete atypical femoral fractures (AFFs) earlier than radiographs, there is no study on predicting further progression to a complete fracture among incomplete AFFs. Our purposes are to determine whether bone scan detects impending complete fracture among incomplete AFFs. METHODS: We reviewed 18 patients (20 AFFs) who underwent bone scan at the diagnosis of incomplete AFF and were not treated with prophylactic fixation. A diagnosis of impending complete fracture was made, when the femur completely fractured within 6 months after the scan. We correlated radioisotope uptake with the impending complete fracture to calculate sensitivity, specificity, positive predictive value and negative predictive value of bone scan. RESULTS: Thirteen AFFs (65%, 13/20) showed a positive uptake in bone scan. Among the 13, only one femur was completely fractured within 6 months. None of the 7 femurs without uptake in bone scan fractured. In diagnosing impending complete fracture, the sensitivity of bone scan was 100% and negative predictive value was 100%. However, the specificity (36.8%) and positive predictive value (7.7%) were quite low. CONCLUSION: Bone scan has no significant role in detecting the impending complete fracture, and a positive uptake does not mean the necessity of prophylactic fixation of incomplete AFF.
