ナビゲーションTKAにおける術中キネマティクスと膝関節可動域の検討

抄録

Objective: Recently, studies have demonstrated a relationship between pre- and postoperative kinematics and postoperative clinical outcome in total knee arthroplasty (TKA) using navigation systems. This study aimed to evaluate the relationship between intraoperative knee kinematic patterns and range of motion (ROM) after TKA.

Methods: Forty-five knees in 45 patients receiving primary TKA were assessed. Computed tomography-free navigation system and ATTUNE^® PS-type knees (DePuy, Warsaw, IN, USA) were used in all patients. The mean age of patients was 74.3 years, and the mean follow-up period was 34 months. Subjects were divided into two groups based on the intraoperative kinematic pattern: medial pivot group (MP group) and non-medial pivot group (NMP group). ROM and Japanese Orthopedic Association (JOA) score were measured preoperatively and at a minimum 2-year follow-up. These values were compared between the MP and NMP groups.

Results: Twenty-eight (62%) knees demonstrated an intraoperative medial pivot pattern (MP group), and the remaining 17 (38%) knees demonstrated a non-medial pivot pattern (NMP group). The mean postoperative knee extension angle in the MP group was significantly smaller than that in the NMP group (−0.1±0.3° vs. −1.8±3.0°, respectively; P<0.05). The mean improvement angle of both the knee extension and the flexion in the MP group was significantly larger than that in the NMP group (7.3±8.6° vs. 3.8±6.5° for extension, respectively, and 6.8±14° vs. 1.5±16.1° for flexion, respectively; P<0.05). The mean postoperative JOA score in the MP group was significantly better than that in the NMP group (89.6±4.9 vs. 85.9±8.1, respectively; P<0.05).

Conclusion: An intraoperative medial pivot pattern may predict significant improvement in terms of ROM and clinical outcome at 3-years follow-up after TKA.