[Modified Lemaire procedure in anterior cruciate ligament reconstruction with highly positive pivot shift test]

To explore the effectiveness of the modified Lemaire procedure in anterior cruciate ligament reconstruction (ACLR) in patients with a highly positive pivot shift test.

The clinical data of 18 patients with anterior cruciate ligament (ACL) rupture and highly positive pivot shift test between April 2020 and September 2022 were retrospectively analyzed. There were 13 males and 5 females with an average age of 28.3 years (range, 17-41 years). Causes of injury included 11 cases of direct violence injury, including 6 cases of traffic accident injury, 4 cases of sports injury, 1 case of falling injury; 7 cases of indirect violence injury, all sports injury. All patients had complete ACL rupture, including 15 acute injuries and 3 old injuries. The preoperative pivot shift test was grade Ⅱ in 9 cases and grade Ⅲ in 9 cases. All patients were treated with ACLR combined with modified Lemaire procedure. The International Knee Documentation Committee (IKDC) score and Lysholm score were used to evaluate the effectiveness before operation and at 3, 6, 12 months after operation. KT-2000 arthrometer was used to measure the anterior stability of the knee joint, and the difference between the healthy and affected sides was recorded. Pivot shift test was used to evaluate the rotational stability of the knee joint. During the follow-up, X-ray films were taken to observe the bone tunnel and internal fixation, and MRI was used to examine the healing of ACL, anterolateral collateral ligament and fibular collateral ligament grafts.

All patients completed the operation successfully without complications such as knee joint infection, vascular and nerve injury. All patients were followed up 12-19 months (mean, 13.2 months). After operation, the rotational stability of the knee joint recovered satisfactorily, and there was no adverse symptom such as knee instability and locking at last follow-up. X-ray film and MRI showed that the bone tunnel was anatomically located and healed well, the internal fixation was in good position, and the reconstructed ACL and iliotibial band were continuous and in good tension. The IKDC score, Lysholm score, and the difference of KT-2000 between the healthy and the affected sides significantly improved at 3, 6, and 12 months after operation ( P<0.05). All the indicators further improved with time after operation, except that there was no significant difference in IKDC score between 3 and 6 months after operation and in the difference of KT-2000 between 3 months and 6, 12 months after operation ( P>0.05), and there were significant differences in other indicators between different time points ( P<0.05). Pivot shift test was negative immediately after operation and at last follow-up.

In ACL injuries with a highly positive pivot shift test, ACLR combined with the modified Lemaire procedure can effectively restore anterolateral knee stability, leading to satisfactory knee stability and function in the early postoperative period.