Erratum to: Difficult Cases in Robotic Arm-Assisted Total Knee Arthroplasty: A Case Series

The authors would like to make some modifications to the text and figures published in the above article in the Journal of Knee Surgery, Volume 31, Number 1, 2018 (DOI: 10.1055/s-0037-1608839).

1. In Case 1, History, para 1, sentence 4, “Examination revealed a correctable varus deformity of approximately 9 degrees, flexion to 110 degrees, and an extension lag of approximately 10 degrees” should read as “Examination revealed a correctable valgus deformity of approximately 9 degrees, flexion 10 to 110 degrees, and a flexion contracture of approximately 10 degrees.”

2. In Case 1, History, para 1, sentence 5, “Multiple imaging views of the knee revealed decreased joint space in the medial and patellofemoral compartments, mild sclerosis, and osteophytes in the medial compartment (see ▶Fig. 1)” should read as “Multiple imaging views of the knee revealed decreased joint space in the lateral and patellofemoral compartments, mild sclerosis, and osteophytes in the lateral compartment (see ▶Fig. 1).”

3. In Case 1, Operative Details, para 2, sentence 2, “This was then followed by collecting data points in both extension and flexion at 90 degrees with correction of the varus knee malalignment to neutral at both positions” should read as “This was then followed by collecting data points in both extension and flexion at 90 degrees with correction of the valgus knee malalignment to neutral at both positions.”

4. In Case 1, Operative Details, para 2, sentence 4, “This was achieved by rotating the virtual tibia 1 degree valgus to increase the medial extension gap, as well as moving the tibial cut 2 mm distally, and moving the femoral component 1 mm anteriorly to increase the flexion gap (see ▶Fig. 4)” should read as “This was achieved by rotating the virtual tibia 1 degree varus in order to increase the lateral extension gap, as well as moving the tibial cut 2 mm distally, and moving the femoral component 1 mm anteriorly in order to increase the flexion gap (see ▶Fig. 4).”

5. In Discussion, para 1, sentence 5, “Two of the patients had knee deformities of more than 12 degrees, which were corrected to within 3 degrees of neutral” should read as “Two of the patients had substantial knee deformities, which were corrected to within 3 degrees of neutral.”

6. Figure 1 caption “Preoperative anteroposterior, lateral, tunnel, and sunrise radiographs demonstrating varus deformity flexion deformity of the left knee” should read as Preoperative anteroposterior, lateral, tunnel, and sunrise radiographs demonstrating valgus deformity flexion deformity of the left knee.”

7. Figure 10 caption “Postoperative anteroposterior and lateral views demonstrating neutral coronal alignment of the left knee” should read as “Postoperative anteroposterior and lateral views demonstrating neutral coronal alignment of the left knee. The native femoral anatomy had slight bony deformity, which was corrected for during prosthesis implantation.”