Fu et al reported models for outcomes after hip arthroplasty in an elderly Asian adult with a femoral neck fracture. One model predicts post-operative walking ability. The authors are from Guangdong Academy of Medical Sciences in China.
Patient: Asian patient >= 65 years old with femoral neck fracture
Outcome: 1-year walking ability
Parameters:
(1) surgical procedure
(2) anesthesia
(3) Charlson comorbidity index (CCI)
(4) gender
(5) smoking history
(6) preoperative chest radiograph
(7) preoperative walking ability
(8) age in years, from 55 to 100
(9) serum albumin in g/L, from 20 to 65
points for age =
= (0.992 * (age)) - 54.56
points for serum albumin =
= 144.444 - (2.222 * (albumin))
|
Parameter
|
Finding
|
Points
|
|
surgical procedure
|
total hip arthroplasty (THA)
|
0
|
|
|
HA (presumably hemi-arthroplasty)
|
27.34
|
|
anesthesia
|
spinal anesthesia
|
0
|
|
|
peripheral nerve block
|
4.63
|
|
|
general anesthesia
|
27.34
|
|
Charlson comorbidity index
|
<= 4
|
0
|
|
|
> 4
|
7.182
|
|
sex
|
female
|
0
|
|
|
male
|
19.53
|
|
smoking history
|
no
|
0
|
|
|
yes
|
86.49
|
|
chest X-ray
|
normal
|
0
|
|
|
abnormal
|
23.44
|
|
walking ability
|
free walking
|
0
|
|
|
needs assistance
|
40.34
|
|
|
bedridden
|
61.38
|
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 9.92 (nomogram shows age >= 55 but study was >=65)
• maximum score: 397.97
value of X =
= (0.03447 * (score)) - 5.879
probability of being unable to walk =
= 1 / (1 + EXP((-1) * X))
Performance:
• The bias corrected C-index is 0.81 in the derivation and 0.76 in the validation cohorts.
