Kawano et al reported a clinical prediction rule for evaluating a patient for likelihood of physical activity after total hip arthroplasty (THA). This can help to identify a patient who may require more aggressive management. The authors are from Kyoto University in Japan.
Outcome: physical activity at 1 year after primary THA (sufficient if UCLA activity score >= 6)
Evaluation: protocol for strength testing described under Data Collection
Parameters:
(1) age in years
(2) preoperative UCLA activity score
(3) preoperative hip abduction strength (using a handheld dynamometer), in Nm/kg
(4) preoperative knee extension strength (using IsoForce GT-330 system), in Nm/kg
(5) 10 meter walking test (10MWT) at 3 weeks after surgery
|
Parameter
|
Finding
|
Points
|
|
age in years
|
<= 70.5
|
1
|
|
|
> 70.5
|
0
|
|
UCLA severity score
|
>= 3.5
|
1
|
|
|
< 3.5
|
0
|
|
hip abduction strength
|
>= 0.54 Nm/kg
|
1
|
|
|
< 0.54
|
0
|
|
knee extension strength
|
>= 1.04 Nm/kg
|
1
|
|
|
< 1.04
|
0
|
|
10 meter walk test
|
<= 8.49
|
1
|
|
|
> 8.49
|
0
|
total score =
= SUM(points for all of the parameters)
Interpretation:
• minimum score: 0
• maximum score: 5
• A score >= 4 predicts sufficient activity level after the THA.
Performance:
• The cutoff >= 4 has a positive likelihood ratio of 5.94 and probability of 85%.
• A score of 5 had a probability of 95%.
