Balcarek et al reported a score for predicting recurrent patellar dislocation. This can help to identify patients who may or who may not respond to conservative therapy. The authors are from University Medical Centre Gottingen.
Exam: knee MRI
Parameters:
(1) age in years
(2) bilateral instability
(3) trochlear dysplasia
(4) patellar height (evaluated in sagittal T1-weighted image using the Insall and Salvati index)
(5) tibial tuberosity to trochlear groove (TT-TG) distance in mm (range in study from 7 to 27)
(6) patellar tilt degrees
Parameters
Finding
Points
age in years
> 16 years
0
<= 16 years
1
bilateral instability
no
0
yes
1
trochlear dysplasia
none
0
mild
1
severe
2
patellar height
<= 1.2
0
> 1.2
1
TT-TG
< 16 mm
0
>= 16 mm
1
patellar tilt
<= 20 degrees
0
> 20 degrees
1
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 7
• A score >=4 had an odds ratio of recurrent dislocations was 4.9.
Performance:
• The area under the ROC curve is 0.77.
To read more or access our algorithms and calculators, please log in or register.
