Clinical and Radiological Outcomes After Lateral Meniscal Allograft Transplantation Through a Medial Arthrotomy: A Minimum 4-Year Follow-up.

Background: Previous studies have demonstrated that lateral meniscal allograft transplantation (MAT) through medial arthrotomy showed less extrusion than that of the lateral arthrotomy. However, there is a paucity of literature reporting clinical and radiological outcomes after lateral MAT through the medial arthrotomy.

Hypothesis: Lateral MAT through a medial arthrotomy would show significantly improved clinical scores and minimal joint space narrowing compared with preoperative status.

Study Design: Case series; Level of evidence, 4.

Methods: Between 2001 and 2019, a retrospective chart review was conducted for all patients who underwent lateral MAT using the bony bridge technique through medial arthrotomy. Inclusion criteria were patients who underwent lateral MAT after subtotal or total meniscectomy of the lateral meniscus. A total of 27 patients who were not followed up for >4 years or had follow-up magnetic resonance imaging after surgery were excluded. At final follow-up, Lysholm scores and Tegner activity scale scores were collected. Graft extrusion, trough angle, and position of the bony bridge were measured by magnetic resonance imaging at 6 months after MAT. Joint space width (JSW) of the lateral compartment on Rosenberg view was measured and compared preoperatively and at follow-up.

Results: A total of 28 patients were included in this study. Their mean age was 29.8 years (range, 15-48 years) with a mean follow-up of 11.4 years. Preoperative Lysholm scores and Tegner activity scale scores (66.5 ± 16.6 and 3.1 ± 1.9, respectively) significantly improved at follow-up (84.8 ± 11.1 [ < .001] and 4.4 ± 1.5 [ = .008], respectively). The JSW decreased from 6.2 ± 1.6 mm to 5.7 ± 1.4 mm ( = .014). Extrusion was 2.2 ± 1.5 mm, and trough angle was 1.5°± 8.9°. The bony bridge was positioned at 43.9% ± 4.3% from the lateral edge on the entire tibial plateau. Nine patients (32.1%) underwent subsequent procedures. Partial meniscectomies were performed in 2 patients, meniscal repairs in 2, manipulation under anesthesia in 1, and lateral capsular plication in 1. Three patients who underwent total meniscectomy or revision surgery were regarded as having a failure; therefore, 89.3% grafts survived.

Conclusion: Lateral MAT through the medial arthrotomy demonstrated satisfactory clinical and radiological outcomes at long-term follow-up.