Redmond et al reported a model for predicting total hip arthroplasty (THA) after arthroscopy. The authors are from American Hip Institute (Westmont, IL), Hinsdale Orthopaedics and Southeast Orthopedic Specialists (Jacksonville, FL).
Patient selection: age from 10 to 80 years, symptomatic labral tear
Patient exclusion: previous hip conditions
Parameters:
(1) age in years. from 10 to 80
(2) preop modified Harris hip score, from 0 to 100
(3) femoral anteversion, from -30 to 50
(4) lateral center-edge angle (LCEA), from 10 to 55
(5) acetabular outerbridge, from 0 to 4
(6) revision arthroscopy
(7) femoral outerbridge, from 0 to 4
|
Parameter |
Finding |
Points |
|
age |
10 |
0 |
|
|
15 |
2 |
|
|
20 |
4 |
|
|
25 |
6 |
|
|
30 |
8 |
|
|
35 |
10 |
|
|
40 |
12 |
|
|
45 |
14 |
|
|
50 |
16 |
|
|
55 |
18 |
|
|
60 |
20 |
|
|
65 |
22 |
|
|
70 |
24 |
|
|
75 |
26 |
|
|
80 |
28 |
|
modified Harris |
0 |
22 |
|
|
10 |
20 |
|
|
20 |
18 |
|
|
30 |
16 |
|
|
40 |
14 |
|
|
50 |
12 |
|
|
60 |
10 |
|
|
70 |
8 |
|
|
80 |
6 |
|
|
90 |
4 |
|
|
100 |
2 |
|
femoral anteversion |
-30 |
21 |
|
|
-20 |
19 |
|
|
-10 |
16 |
|
|
0 |
13 |
|
|
10 |
10 |
|
|
20 |
8 |
|
|
30 |
5 |
|
|
40 |
3 |
|
|
50 |
0 |
|
LCEA |
10 |
24 |
|
|
15 |
21 |
|
|
20 |
19 |
|
|
25 |
16 |
|
|
30 |
14 |
|
|
35 |
11 |
|
|
40 |
8 |
|
|
45 |
5 |
|
|
50 |
3 |
|
|
55 |
0 |
|
acetabular outerbridge |
0 |
9 |
|
|
1 |
0 |
|
|
2 |
9 |
|
|
3 |
14 |
|
|
4 |
15 |
|
revision surgery |
no |
0 |
|
|
yes |
8 |
|
femoral outerbridge |
0 |
4 |
|
|
1 |
0 |
|
|
2 |
10 |
|
|
3 |
10 |
|
|
4 |
13 |
If this data is analyzed:
points for age = (0.4 * (age)) - 4
points for femoral anteversion = (0.000184 * ((angle)^2)) - (0.2687 * (score)) + 13.1
points for LCEA = 29.39 - (0.5321 * (LCEA))
points for modified Harris = 22 - (0.2 * (Harris))
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 2
• maximum score: 110
|
Total Score |
Risk of THA at 27 Months |
|
49 |
0.01 |
|
55 |
0.02 |
|
61 |
0.04 |
|
69 |
0.10 |
|
75 |
0.20 |
|
82 |
0.40 |
|
89 |
0.70 |
|
94 |
0.90 |
|
100 |
0.99 |
value of X =
= (0.00008342 * ((score)^3)) - (0.01635 * ((score)^2)) + (1.172 * (score)) - 32.69
|
Score |
|
|
< 49 |
< 1% |
|
49 to 100 |
1 / (1 + EXP((-1) * X) |
|
> 100 |
> 99% |
Specialty: Surgery, orthopedic
