Subvastus approachによる最小侵襲人工膝関節全置換術の短期成績

Short-term Outcome of Minimally Invasive Total Knee Arthroplasty by a Subvastus Approach

　2004年10月から変形性膝関節症に対し，subvastus approachによる最小侵襲人工膝置換術MIS-TKAを施行し，1年以上経過観察した51例54膝を調査した．皮切長は平均7.8cm，平均手術時間は98分であった．手術時間にはlearning curveが認められた．術後機能評価およびX線評価ではおおむね満足な結果が得られた．MIS-TKAは術後の後療法と入院期間の短縮に有用であった．MIS-TKA施行にあたり，十分な視野が得られない場合は，皮切の長さに固執せず皮切を延長することが重要である．

　In this study fifty-one patients (54 knees) who underwent minimally-invasive total knee arthroscopy (MIS-TKA) with a SCORPIO NRG prosthesis (Stryker) by a subvastus approach since October 2004 were evaluated functionally and radiologically. Average age at the time of surgery was 75.3 years old (65～84 years old). The mean length of the skin incision was 78mm, and mean operation time was 98 minutes. The operation times reflected a learning curve. Postoperative X-rays revealed that the target implantation angle had been achieved. The Japanese Orthopaedic Association (JOA) score for osteoarthritis improved from an average value of 36.5 before surgery to an average value of 85.0 points after surgery. Accurate evaluation for surgical indications, precise preoperative planning, and meticulous confirmation of alignment during surgery are important to achieving a successful short-term outcome. It is important to extend the skin incision, if exposure is insufficient.