Rotatory stability of the knee after arthroscopic meniscus suture repair: a 5-to-17-year follow-up study of isolated medial and lateral meniscus tears.

The long-term rotatory stability of meniscus suture repair has not been firmly established clinically. Up to now there are only experimental studies done. This retrospective study aimed to compare the long-term rotatory stability of a knee with a meniscus suture repair with the stability of the uninjured knee in each of a cohort of patients. We evaluated both knees of 64 patients at an average follow-up of 11 years (range : 5 to 17) after successful arthroscopic meniscus suture repair. Each patient's injury was an isolated longitudinal-vertical meniscus tear and each patient's opposite knee was uninjured. All repairs were performed with the same outside in meniscus suture repair technique. Evaluation included standardised clinical examination, anterior stability testing with a ligament testing device, and rotational testing with a rotational laxiometer. In the stability assessments, the mean anteroposterior translation was the same for repaired and uninjured knees: 3 mm at 67 N and 5 mm at 89 N. The mean external rotation was the same in repaired knees and uninjured knees at 20 degrees of flexion (22 degrees) and similar in repaired knees (22 degrees) and uninjured knees (23 degrees) at 90 degrees flexion. The mean internal rotation was similar in repaired knees (12 degrees) and uninjured knees (13 degrees) at 20 degrees and 90 degrees of flexion. Our findings indicate that a knee with arthroscopic meniscus suture repair displays a rotational stability that is equal to or nearly equal to the stability of an uninjured knee. However, whether rotational stability will only be preserved due to meniscus repair and how much of the meniscus needs to be preserved in order to maintain the biomechanical stability of the knee remains unclear.