[The mini-midvastus approach for total knee arthroplasty]. / Der Mini-Midvastus-Zugang zur Implantation von Kniegelenkendoprothesen.

OBJECTIVE: Minimally invasive approach to the knee for total knee arthroplasty to reduce soft-tissue trauma. INDICATIONS: Total knee replacements. Revision surgery after total knee arthroplasty. CONTRAINDICATIONS: Severe obesity. Revision surgery with preoperative flexion<90 degrees. SURGICAL TECHNIQUE: Anterior midline incision, blunt separation of the distal part of the oblique fibers of the vastus medialis over a length of 1-3 cm. The muscle split ends at the proximal medial corner of the patella. The incision is continued medially of the patella ending at the tibial tuberosity. After approaching the joint, the patella is shifted laterally without dislocating it, thus exposing the articular surfaces. Surgery is performed in maximal knee flexion of 90 degrees . After insertion of the components, stepwise wound closure and only superficial adaptation of the muscle split. POSTOPERATIVE MANAGEMENT: Mobilization with weight bearing and range of motion as tolerated. RESULTS: In a prospective study, 267 knee prostheses were implanted between 2005 and 2007 using the mini-midvastus approach. All patients (160 female, 107 male, average age 69.3 years [46-89 years]) were examined clinically and radiologically prior to and 6 weeks after surgery. The clinical results were based on the American Knee Society Score, which increased from a preoperative value of 48.9 (32-68) to 86.5 (75-100) at follow-up. Radiologically, 92.1% of the knees showed a malposition<3 degrees.