[Anatomic reconstruction of the anterior cruciate ligament in single bundle technique].

OBJECTIVE: Restore the knee stability by ACL reconstruction of the anterior cruciate ligament. INDICATION: Acute and chronic functional instability with rupture of the anterior cruciate ligament giving way phenomena, acute rupture of the anterior cruciate ligament with concomitant meniscus repair. CONTRAINDICATIONS: Local infection in the knee joint, local soft tissue damage, lack of cooperation of the patient. SURGICAL TECHNIQUE: The operation begins with the examination under anesthesia. It follows an arthroscopic examination of the knee and the arthroscopic treatment of accompanying intra-articular lesions (meniscus and cartilage damage). The semitendinosus tendon is harvested via a 3 cm skin incision medial to the tibial tuberosity. A four stranded tendon graft is prepared with a minimum length of 6.5 cm. Alternative grafts for this technique are the patellar tendon, quadriceps tendon, and allografts. The femoral tunnel for the ACL graft is drilled via a deep anteromedial portal under arthroscopic control. For precise placement of the guide wire a specific offset aimer is used. For drilling the knee must be flexed more than 110°. Landmarks are the intercondylar line and the cartilage-bone interface. The position of the guide wire is always controlled by the medial portal (medial portal view). The guide wire is overdrilled with a cannulated drill (4.5 mm when a flip tack is used). The drill diameter for the 30 mm long blind tunnel is chosen according to the graft diameter. A gentle tunnel preparation may be achieved with the use of dilators. At the tibia, the anterior horn of the lateral meniscus is used as a landmark in the absence of ACL stump. The guide wire is first overdrilled with a 6 mm drill. Slight adjustments to the tibial tunnel location can be archieved when the guide wire is overdrilled eccentrically with a larger drill. At the femur an extracortical fixation technique with a flip button is preferred. At the tibia, a hybrid fixation with absorbable interference screw and button is used. REHABILITATION: The rehabilitation program is divided into three phases. During the inflammatory phase (1st-2nd week) control of pain and swelling is recommended. The patient is immobilized with 20 kg partial weight bearing. During the proliferative phase (3 nd-6th week), load and mobility are slowly increased. Goal of this phase is it full extension. Exercises should be performed in a closed chain. During the remodeling phase strength and coordination exercises can be started. Athletes should not return to competitive sports before the 6th to 8th month.
RESULTS: In a prospective study, we have examined 21 patients treated with an anatomic anterior cruciate ligament reconstruction in single-bundle technique, after two years. As graft the semitendinosus was used. The postoperative MRI diagnosis showed that all tunnels were positioned anatomically. KT 1000 measurement showed that the difference of anterior translation decreased from an average of 6.4-1.7 mm. A sliding pivot shift phenomenon was detected in only one patient. The postoperative Lysholmscore was 94.2 points.