Table 4: The formula in Fig. (1) is used in di/hemiplegic patients to calculate the percentage of GM muscle length in comparison to the leg length.
| Age |
GM Muscle length (cm) |
Leg length |
% Leg length |
| 3.1 |
8.6 |
19.6 |
43.9 |
| 5.6 |
10.7 |
25 |
42.8 |
| 2.8 |
8.3 |
17 |
48.8 |
| 8.3 |
12.1 |
26 |
46.5 |
| 8.3 |
11.8 |
27 |
43.7 |
| 9.3 |
12 |
27.5 |
43.6 |
| 9.3 |
13 |
26 |
50 |
| 13.1 |
18.5 |
37 |
50 |
| 13.4 |
15 |
34 |
44.1 |
| 14.1 |
13.7 |
38.8 |
35.3 |
We used this round figure of 45% when calculating GM muscle length. The surgeon will measure leg length from the tibiofemoral joint line to the lateral malleolus. Multiplying the measured length with 0.45% will calculate GM muscle length.