Ankle fractures have features of an osteoporotic fracture
Kyoung Min Lee MD
Department of Orthopaedic SurgerySeoul National University Bundang Hospital
Disclosures
The authors have no disclosures.
Introduction
Osteoporosis is a serious disease with high morbidity and mortality caused by fragility fractures, especially hip and spine fractures
Osteoporotic fracture is a special treatment problem that needs special care and instruments in operative treatment - poor fixation stability, more comminution?
Introduction
What is osteoporotic fracture? - fracture on osteoporotic bone
Osteoporosis - loss of bone mineral density - age, gender dependent (hormone)
Introduction
Is ankle fracture an osteoporotic fracture? - increasing incidence after menopause - and ??
Thur et al. 2012
Purpose
Investigate osteoporotic features of ankle fractures in terms of
(1) bone attenuation on CT (BMD)
(2) degree of trauma between the ages over 50 years and less than 50 years in patients with ankle fractures.
Materials and Methods
Retrospectively reviewed 194 consecutive patients with ankle fractures
CT examination
Exclusion : 30 patients - previous Op - congenital malformation - neuromuscular diseases - tumors or infections - interval of more than one week between the injury and CT examination
Demographic data - age, genderMechanism of injury - high/low energy traumaFracture type - medial malleolar, lateral malleolar, bimalleolar, trimalleolarBone attenuation on CT - ROI tool - talus, DT, LM, MM
Materials and Methods
Bone attenuation (housefield unit, ROI)
Bone attenuation (housefield unit, ROI)
Bone attenuation (housefield unit, ROI)
Data analysis
Reliability of CT measurement - ICC
Comparison between younger (<50 yrs) and older (>50 yrs) - t-test - chi-square test
Multiple regression analysis - effect of age and gender on bone attenuation
Results
Table 1. Data summary
Number of patients 194
Mean age (years) 51.0 (SD 15.8)
Male : Female, n (%) 98 (50.5) : 96 (49.5)
Right : Left, n (%) 109 (56.2) : 85 (43.8)
Low energy trauma : high energy trauma, n (%) 167 (86.1) : 27 (13.9)
Fracture type (medial malleolar/lateral malleolar/bimalleolar/trimalleolar)
23/76/58/37
Average bone attenuation on CT
talus (HU) 350.7 (SD 97.3)
medial malleolus (HU) 293.1 (SD 101.0)
lateral malleolus (HU) 234.5 (SD 93.5)
distal central tibia (HU) 184.5 (SD 77.6)SD, standard deviation; HU, housefield units.
Table 2. ICC values of inter- and intraobserver reliabilities of bone attenuation measurements
Talus Medial malleolus Lateral malleolus Distal central tibia
Interobserver
0.988 (0.970 to 0.995)
0.888 (0.739 to 0.954)
0.895 (0.756 to 0.957)
0.875 (0.712 to 0.949)
Intraobserver
0.983 (0.958 to 0.993)
0.981 (0.953 to 0.992)
0.986 (0.964 to 0.994)
0.943 (0.846 to 0.978)
Data are presented as ICC (95% confidence interval)
Table 3. Comparison between the younger and older age groups in male patients
Younger age group Older age group p-value
Number of patients 53 45 -
Mean age (years) 35.8 (SD 8.9) 64.3 (9.3) <0.001
Low energy trauma : high energy trauma, n (%)40 (75.5) : 13 (24.5)
40 (88.9) : 5 (11.1)
0.087
Fracture type (medial malleolar/lateral malleolar/bimalleolar/trimalleolar)
7/27/14/5 8/12/10/15 0.012
Average bone attenuation on CT
talus (HU) 392.7 (SD 85.1) 346.2 (SD 82.5) 0.008
medial malleolus (HU) 338.1 (SD 104.6) 296.4 (SD 86.1) 0.036
lateral malleolus (HU) 297.5 (SD 89.4) 233.7 (SD 69.1) <0.001
distal central tibia (HU) 225.5 (SD 85.9) 175.3 (SD 62.7) 0.002
SD, standard deviation; HU, housefield units.
Table 4. Comparison between the younger and older age groups in female patients
Younger age group
Older age group p-value
Number of patients 35 61 -
Mean age (years) 36.9 (SD 8.1) 62.4 (SD7.1) <0.001
Low energy trauma : high energy trauma, n (%) 28 (80) : 7 (20)59 (96.7) : 2 (3.3)
0.011*
Fracture type (medial malleolar/lateral malleolar/bimalleolar/trimalleolar)
7/14/8/6 1/23/26/11 0.009
Average bone attenuation on CT
talus (HU) 395.8 (SD 98.5) 291.7 (SD 85.9) <0.001
medial malleolus (HU) 321.2 (SD 86.0) 235.4 (SD 89.8) <0.001
lateral malleolus (HU) 245.6 (SD 86.8) 174.1 (SD78.6) <0.001
distal central tibia (HU) 216.0 (SD 55.3) 137.7 (SD 63.4) <0.001
SD, standard deviation; HU, housefield units; *, Fisher exact test.
Table 5. Effects of age and gender on bone attenuation in multiple regression analysisDependent variable (bone attenuation)
Independent variable Beta 95% CI p-value
Talus
Age -2.4 -3.2 to -1.6 <0.001
Gender -31.3 -56.3 to -6.3 0.014
Constant 52.1.7 469.1 to 574.4 <0.001
Medial malleolus
Age -2.5 -3.3 to -1.7 <0.001
Gender -41.8 -67.4 to -16.1 0.002
Constant 482.5 428.4 to 536.6 <0.001
Lateral malleolus
Age -2.6 -3.3 to -1.9 <0.001
Gender -57.0 -79.2 to -34.9 <0.001
Constant 451.6 405.0 to 498.3 <0.001
Dista central tibia
Age -2.3 -2.9 to -1.7 <0.001
Gender -26.4 -45.3 to -7.4 0.007
Constant 342.5 302.5 to 382.4 <0.001CI, confidence interval. In multiple regression analysis, dependent variable is bone attenuation (a surrogate marker of bone mineral density) of each bony structure, and independent variables are age and gender.Age and female gender show negative effect on bone attenuation.
Conclusions
- Ankle fracture had features of osteoporotic fracture that is characterized by age and gender dependent low bone attenuation. Ankle fracture should not be excluded from the clinical and research interest as well as from the benefit of osteoporosis management.
This study has been accepted in Osteoporos Int (IF=4.8)
Thank you!
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