A comparison of registration errors with imageless computer navigation during MIS total knee arthroplasty versus standard incision total knee arthroplasty: a cadaveric study

*The research took place at St. Michael’s Hospital, University of Toronto, Toronto, Ontario, Canada.

Figures & data

Table I. The error during registration of each anatomical landmark using each approach.

		MIS			Standard
Landmark	Plane	Mean	SD	Range	Mean	SD	Range	p Value
Distal femur centre	Coronal	−0.8	2.2	−4.9 to 3.1	0.0	3.0	−6.5 to 5.0	0.415^a
Distal femur centre	Sagittal	−4.6	2.3	−9.2 to 0.2	−6.9	3.3	−13.2 to −0.2	0.000^b
Femur mechanical axis	Coronal	0.0	0.3	−0.7 to 0.5	0.0	0.5	−1.0 to 0.8	0.415^a
Femur mechanical axis	Sagittal	−0.7	0.3	−1.4 to 0.0	−1.0	0.5	−2.0 to −0.2	0.000^b
Lateral epicondyle	Sagittal	−1.0	2.6	−6.9 to 4.9	−2.5	2.7	−8.1 to 6.3	0.006^b
Medial epicondyle	Sagittal	2.1	6.5	−8.9 to 12.6	2.1	6.5	−8.9 to 12.6	0.612^a
Epicondylar axis	Internal rotation	−2.1	4.1	−10.3 to 6.5	−3.1	3.6	−10.3 to 4.8	0.161^b
Proximal tibia centre	Coronal	3.2	2.3	−0.5 to 7.9	3.2	2.2	−2.3 to 9.9	0.950^a
Proximal tibia centre	Sagittal	3.3	3.2	−3.1 to 8.4	3.4	2.3	−0.6 to 9.6	0.841^b
Ankle centre	Coronal	0.9	2.6	−5.0 to 6.1	−0.4	2.8	−6.9 to 4.7	0.029^b
Ankle centre	Sagittal	−4.0	4.2	−14.1 to 3.6	−3.7	3.7	−12.9 to 3.7	0.754^b
Tibia mechanical axis	Coronal	0.4	0.6	−0.7 to 1.5	0.6	0.6	−1.0 to 1.6	0.090^b
Tibia mechanical axis	Sagittal	−1.1	1.0	−2.9 to 0.6	−1.1	0.8	−3.2 to 0.6	0.950^a

^aWilcoxon signed-rank test.

^bPaired t-test.

Figure 1. Boxplot of the error in the registration of anatomical landmarks in the femur. •: Outliers between ×1.5 and ×3 the interquartile range. *p < 0.05. MIS, minimally invasive approach; STD, standard approach.

Figure 2. Boxplot of the error in calculation of the mechanical axis of the femur. •: Outliers between ×1.5 and ×3 the interquartile range. *p < 0.05. MIS, minimally invasive approach; STD, standard approach.

Figure 3. Boxplot of the error in the registration of anatomical landmarks in the tibia and ankle. •: Outliers between ×1.5 and ×3 the interquartile range. *: p < 0.05. MIS, minimally invasive approach; STD, standard approach.

Figure 4. Boxplot of the error in calculation of the mechanical axis of the tibia. •: Outliers between ×1.5 and ×3 the interquartile range. MIS, minimally invasive approach; STD, standard approach.

Figure 5. Boxplot of the error in the registration of the epicondyles. •: Outliers between ×1.5 and ×3 the interquartile range. *: p < 0.05. MIS, minimally invasive approach; STD, standard approach.

Figure 6. Boxplot of the error in the calculation of the transepicondylar axis. MIS, minimally invasive approach; STD, standard approach.