The purpose of our study was to determine the effectiveness of primary repair of arcuate ligament complex in posterolateral rotary instability of knee.

We reviewed the clinical records and operative notes of 9 patients who were treated by primary repair for the acute posterolateral rotary instability and followed more than 1 year. All the 9 knees had a positive external rotation recurvatum test and a positive posterolateral drawer test, One or more components of the arcuate ligament complex were injured in all cases and associated injuries were posterior cruciate ligament rupture in 6, lateral collateral ligament in 5, anterior cruciate ligament partial rupture in 2, biceps femoris rupture in 2, meniscus tear in 3, iliotibial band rupture in 1, ipsilateral femur fracture in 1 and peroneal nerve palsy in 1.

By objective rating index, the results were classified as good (4 patients), fair (4 patients) and poor (1 patient). By functionally, the results were classified as good (6 patients), fair (3 patients).

Consequently, we believe that primary repair of arcuate ligament complex in acute stage can result in objectively and functionally acceptable knee function.