Total knee arthroplasty (TKA) and high tibial osteotomy (HTO) are different procedures on the continuous spectrum of osteoarthritic knee treatments. TKA aims for neutral alignment and HTO aims for slight valgus. 2:2:2:1 propensity score matching yielded 100, 100, 100, and 50 patients with unilateral TKA, bilateral TKA, unilateral HTO, and bilateral HTO, respectively. Radiological evaluations of pelvis, knee, ankle, and hindfoot were performed. The important factors affecting the alignment change of the adjacent joints were identified, and subgroup analyses were performed using the identified parameters. The clinical outcomes were also compared. The coronal alignments of the adjacent joints were corrected to the neutral position after TKA and HTO. The tibiotalar tilt angle (TTTA) was a common factor that affected changes in the ankle and hindfoot alignment. Patients with larger preoperative TTTA showed larger changes in TTTA in both TKA and HTO groups (P < 0.001). Patients with larger preoperative hindfoot alignment angle (HAA) showed larger changes in tibial plafond inclination, talar inclination, and HAA in both TKA and HTO groups (P < 0.001). TKA groups showed negative pelvic tilt values in the horizontal plane, and HTO groups showed a larger weight-bearing line ratio. Even more severe deformities including adjacent joints were observed in TKA patients, both TKA and HTO patients showed improved alignment of the adjacent joints. However, HTO patients showed closer normal alignment than patients who underwent TKA. The preoperative TTTA and HAA were important factors for restoration of ankle and hindfoot alignment after knee surgery. Copyright © 2023 Elsevier B.V. All rights reserved.