Fig. 1(A) There was valgus malalignment after tibia nailing. Closing wedge osteotomy was planned and angulation correction axis-center of rotation of angulation (ACA-CORA) was on the concave axis. (B) Intramedullary nail was inserted after the closing wedge osteotomy. (C) Postoperative 6 months radiography shows good alignment with bone union. MPTA: medial proximal tibial angle, LDTA: lateral distal tibial angle.
Fig. 2(A) There was a varus malalignment after distal femur minimally invasive plate osteosynthesis (MIPO). Open wedge osteotomy was planned. (B) The plate was removed through the previous operation site. (C, D) Two shanz pins were inserted into the medial side for deformity correction. (E) Osteotomy was performed at the center of rotation of angulation. (F, G) Two shanz pins were distracted until the mechanical axis showed normal alignment. (H, I) Locking plate was applied using the MIPO technique. (J) Postoperative 10 months radiography shows good alignment with bone union (image courtesy of CW Oh, MD, Kyungpook National University, thank you for your courtesy).
Fig. 3(A) When the center of rotation of angulation (CORA) and angulation correction axis (ACA) are not the same, dome osteotomy will cause translation of the proximal and distal bone axes. (B) When the CORA and ACA are the same, dome osteotomy will correct the angulation deformity without translation.
Fig. 4Graphic method. (A) Magnitude of angulation angulation was measured on anteroposterior (AP) and lateral radiographs (1 mm=1°). True deformity angle was 45° and 30° from the sagittal plane. (B) Closed wedge osteotomy is performed on the forward angulation correction axis (ACA), and opening wedge osteotomy is performed on the backward ACA.
Fig. 5(A) There was a valgus malalignment after proximal femur minimally invasive plate osteosynthesis (MIPO). (B) The angle of 40° internal rotation deformity was found on the computed tomography and physical examination. (C) Two parallel shanz pins were inserted into the proximal and distal segments to correct the rotational deformity after plate removal. (D) Osteotomy was performed at the center of rotation of angulation. (E) Distal shanz pin was externally rotated until the lessor trochanter shape showed to be the same as the opposite site. (F) The plate was bent 8° varus compared with the previous plate to correct the valgus deformity. (G) Locking plate was applied using the MIPO technique. (H) Postoperative 4 months radiography shows good alignment.