Prediction of Postoperative Complications Using Hand Grip Dynamometry

 

Patient selection: 247 normal volunteers used to derive normal values for age and gender with ages from 16 to 95

 

Measurement:

(1) Performed using a mechanical dynamometer.

(2) Results reported in kilograms.

(3) The nondominant hand tends to show slightly great strength (Table III, page 21, Webb (1989).

 

Criteria for serious complication:

(1) post-operative stay > 14 days

(2) death

 

Quadratic Equations for Normal Grip Strength

 

female grip strength in kilograms =

= 25.9 + (0.55 * (age in years)) - (0.0077 * ((age in years)^2))

 

R value: 0.78

 

male grip strength in kilograms =

= 42.03 + (0.57 * (age in years)) - (0.0073 * ((age in years)^2))

 

R value: 0.56

 

from Table II, page 31, Webb et al (1989)

 

cut-off strength in kilograms =

= (grip strength in kilograms for gender and age) * 0.85

 

Exponential Equations for Normal Grip Strength

 

female grip strength in kilograms =

= 3.91 * EXP(-0.012 * (age in years))

 

R value: 0.74

 

male grip strength in kilograms =

= 4.12 * EXP(-0.0049 * (age in years))

 

R value: 0.48

 

from Table II, page 31, Webb et al (1989)

 

NOTE: When age values are entered into the exponential equations, unrealistic values are returned. I tried several variations of the equations and could not get reliable results.

 

Age and Gender Grip Strength Cutoff Values (at 85% of Normal)

age in years	female grip strength in kilograms	male grip strength in kilograms
15	28	42
20	29	43
25	30	44
30	30	45
35	30	45
40	30	45
45	30	45
50	29	45
55	28	44
60	27	43
65	25	41
70	23	39
75	20	37
80	18	35
85	15	32
90	11	29
95	8	26

from Table V, page 32, Webb et al (1989)

 

Medal Equations for Grip Strength Cutoff Values

 

from Figure 3, page 32, Webb et al (1989)

 

female age 15-30 years grip strength in kilograms =

= (-0.01 * ((age in years)^2)) + (0.65 * (age in years)) + 20

 

female age 30-95 years grip strength in kilograms =

= (-0.00483 * ((age in years)^2)) + (0.25193 * (age in years)) + 27.3632

 

male age 15-40 years grip strength in kilograms =

= (-0.00752 * ((age in years)^2)) + (0.5805 * (age in years)) + 34.025

 

male age 40-95 years grip strength in kilograms =

= (-0.004453 * ((age in years)^2)) + (0.2498268 * (age in years)) + 42.665