Affiliations: [a] Department of Orthopaedic Surgery, Akita Rosai Hospital, Odate, Japan | [b] Department of Orthopedic Surgery, Ishibashi General Hospital, Shimotsuke, Japan | [c] Division of Public Health, Center for Community Medicine, Jichi Medical University, Shimotsuke, Japan | [d] Department of Orthopaedic Surgery, School of Medicine, Jichi Medical University, Shimotsuke, Japan | [e] Department of Orthopedic Surgery, Akita University Graduate School of Medicine, Akita, Japan
Correspondence:
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Corresponding author: Tsuneari Takahashi, Department of Orthopedic Surgery, Ishibashi General Hospital, 1-15-4 Shimokoyama, Shimotsuke, Tochigi 329-0596, Japan. Tel.: +81 285 53 1134, E-mail: tsuneari9@jichi.ac.jp.
Abstract: BACKGROUND: A gradually reducing radius (GRADIUS) design implant can facilitate a smooth transition from stability through full range of motion in total knee arthroplasty (TKA). Nonetheless, patient-specific factors associated with good knee flexion remain unclear. OBJECTIVE: This study aimed to determine the factors associated with good knee flexion after cruciate-retaining TKA with a GRADIUS prosthesis in an Asian population. METHODS:This retrospective study included 135 patients that were stratified according to postoperative knee flexion angle (KFA) into Group F (⩾ 120∘; 85 patients [63.2%]) and Group NF (< 120∘; 50 patients [36.8%]). RESULTS: Patients in Group F were taller and had a lower body mass index (BMI) smaller preoperative hipkneeankle angle and better preoperative extension and flexion angle than Group NF patients. The multivariable analysis revealed that patients’ height (odds ratio [OR]: 1.07, P= 0.0150), BMI (OR: 0.85, P= 0.0049), and preoperative flexion angle (OR: 1.06, P= 0.0008) predicted good KFA. The ROC curve analysis showed that the cutoff values of a good KFA were height 155.1 cm, BMI 22.1 kg/m2, and preoperative KFA 120∘. CONCLUSIONS: Patient height, BMI, and preoperative KFA were independent factors affecting good postoperative KFA in patients of Asian descent who underwent cruciate-retaining TKA with a GRADIUS design.
Keywords: Total knee arthroplasty, posterior cruciate ligament retaining, knee flexion, body mass index, height, knee implant
