Preoperative foot and ankle radiographic evaluation for total knee arthroplasty

Purpose: To radiographically evaluate the ankle and foot complications in preoperative patients for total knee arthroplasty (TKA) in Japan. Methods: This study included 500 legs of 500 patients who planned to undergo primary TKA in affiliated hospitals of our university from August 2020 to November 2021. Hip to calcaneus view, anterior view of the ankle joint, and anterior and lateral views of the foot were taken within 1 month preoperatively. We measured hip-knee-ankle angle (HKA), mechanical ankle joint axis point (MAJAP), lateral distal tibial angle (LDTA), tibio-plafound inclination (TPI), talar inclination (TI), ankle joint line convergence angle (A-JLCA), talo-first metatarsal angle (TMA), calcaneal pitch angle (CPA), hallux valgus angle (HVA), first-second intermetatarsal angle (M1M2A), first fifth intermetatarsal angle (M1M5A), talonavicular coverage angle (TNCA), and percentage of Takakura Tanaka classification. Results: Mean measured values were as follows: HKA: 11.0°; MAJAP, 39.6%; LDTA: 92.2°; TPI: 6.9°; TI: 7.2°; A-JLCA: 0.3°; TMA:−4.3° (9° in 373 feet, 74.6%); M1M5A: 31.1°(≥30° in 321 feet, 64.2%); TNCA: 10.6° (≥7° in 375 feet, 75.0%); Takakura Tanaka classification Stage ​≥ ​IIIa in 108 feet, 21.6%. Conclusions: Mild-to-severe hallux valgus was noted in 26.5% of patients and Stage IIIa or higher ankle osteoarthritis in 21.6%, and abnormal alignment—including flat feet—was indicated in some patients. Patient's knee, foot, and ankle symptoms should be considered before TKA.