Posteromedial approach of gastrocnemius for reduction and internal fixation of avulsed tibial attachment of posterior cruciate ligament

摘要

Objective: To introduce a posteromedial approach through the medial border of the medial head of gastrocnemius for reduction and reattachment of bony avulsion of the posterior cruciate ligament (PCL) from the tibia. Methods: Eleven patients with avulsed tibial attachment of the PCL underwent an operative reduction and internal fixation through the posteromedial approach of the gastrocnemius in our department from February 1998 to March 2000. The skin incision was reversed L-shaped along the medial border of the medial head of the gastrocnemius and the posterior capsule was exposed by dissecting the medial border and lateral retraction, avoiding the damage of the popliteal neurovascular structures. After that, the posterior capsule was vertically dissected a little medially to the posterior intercondylar sulcus and just on the posterior medial tibial eminence positioned by finger palpation. Then the PCL and its tibial attachment were easily accessible. In the delayed cases, PCL peripheral releasing was necessary to overcome the ligament retraction and to refresh the fracture bed for optimal reduction and bony healing. At last, one or two biodegradable screws were used to fix the avulsed bone segment and 30° flexion knee plaster cast immobilization was regularly applied after the wound was closed. The evaluation included X-ray, posterior sag sign and posterior drawer test compared with the contralateral side. The functional assessment of the low limbs was not available because of concomitant injuries. Results: The posteromedial approach of the gastrocnemius used in repair of tibial attachment avulsed injury of the PCL could provide benefit of clear anatomical exposure, few blood loss (20 ml on average), no need for detachment or reattachment of any structure. The patients were followed up for 11 months on an average (ranging from 6 months to 2 years). It demonstrated that bony healing was achieved within 4-6 weeks in cases of fresh injury and 7-9 weeks in cases of delayed injury. Six out of 8 fresh cases showed totally negative posterior sag sign or posterior drawer test but 2 had extra laxity for 1-2 mm. In 3 delayed cases, extra laxity for 3-4 mm was presented compared with the contralateral knee. Conclusions; The posteromedial approach of the gastrocnemius is ideal for internal fixation of avulsed tibial attachment of the PCL. It is fairly easy, safe, time-saving, applicable alternatives, in addition, the morbidity is rare and can also be used in management of posteromedial fracture of the medial femoral condyle and tibial plateau.