Effect of Obesity on Component Alignment in Total Knee Arthroplasty

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Figure 1. Radiographic determination of coronal alignment in total knee arthroplasty. Coronal tibiofemoral (left), femoral (middle), and tibial (right) measurements are shown.
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Figure 2. Radiographic determination of sagittal alignment in total knee arthroplasty. Sagittal femoral (left) and tibial (right) measurements are shown.

Table 1. Baseline Demographic Data

Variable	All Patients n = 251	Obese Group n = 149	Nonobese Group n = 102	P Value
Sex				0.2943
Male	96 (38%)	53 (36%)	43 (42%)
Female	155 (62%)	96 (64%)	59 (58%)
Laterality				0.7013
Right knee	117 (47%)	71 (48%)	46 (45%)
Left knee	134 (53%)	78 (52%)	56 (55%)
Mean age, years (range)	66.9 (40-88)	63.9 (40-85)	71.4 (52-88)	<0.001
Mean body mass index, kg/m² (range)	32.7 (20.2-53.0)	37.0 (30.1-53.0)	26.5 (20.2-29.9)

Table 2. Component Alignment Measurements by Group

Radiographic Measurement	Obese Group n = 149	Nonobese Group n = 102	P Value
Coronal tibiofemoral angle	184.1° (180° to 191.0°)	184.7° (178.0° to 191.0°)	0.0556
Coronal femoral component angle	94.6° (88.5° to 101°)	95.9° (90.9° to 98.9°)	0.2246
Coronal tibial component angle	89.7° (84.7° to 95.8°)	89.8° (84.2° to 95.5°)	0.7264
Sagittal femoral component angle	84.7° (75.0° to 93.5°)	85.1° (78.0° to 95.9°)	0.5223
Sagittal tibial component angle	86.6° (80.0° to 95.6°)	86.5° (79.0° to 94.0°)	0.7059