Meniscus allograft transplantation: a comparison of medial and lateral procedures

Because of the anatomic and biomechanical differences between the lateral and medial menisci, it is believed that the indications, combined injuries, techniques, and outcomes of the 2 meniscus allograft transplantation (MAT) procedures may be different.

Medial meniscus transplantation (medial group) usually combines concomitant surgeries, such as anterior cruciate ligament (ACL) reconstruction, so the medial group will have worse clinical results than the lateral group (lateral meniscus transplantation).

Cohort study; Level of evidence, 3.

A retrospective study was conducted on 91 patients who underwent MAT (lateral group, n = 56; medial group, n = 35). There were 33 patients with an absence of a concurrent injury (isolated group) and 58 patients with the presence of a concurrent injury (combined group). The mean follow-up was 40 months (range, 24-125 months). Clinical outcomes for range of motion (ROM), visual analog scale (VAS) for pain score, International Knee Documentation Committee (IKDC) subjective score, Lysholm score, and Tegner activity score were evaluated, and an objective evaluation was performed using magnetic resonance imaging (MRI) and second-look arthroscopic surgery.

At final follow-up, the mean results for ROM, VAS score, IKDC subjective score, Lysholm score, Tegner activity score, and patient subjective satisfaction were not statistically different between the lateral and medial groups (P > .05). The VAS and Lysholm scores of the isolated group were significantly better than those of the combined group. Follow-up MRI was performed on 35 patients (24 in the lateral group and 11 in the medial group). Mean graft extrusion was 1.7 mm in the lateral group and 2.6 mm in the medial group (P = .075). The relative percentage of extrusion was 19.4% in the lateral group and 32.0% in the medial group (P = .011). Anterior cruciate ligament reconstruction occurred more commonly in the medial group, and cartilage procedures occurred more commonly in the lateral group.

The clinical results of the lateral group were not different from those of the medial group. More graft extrusion was found in the medial group on MRI, and second-look arthroscopic surgery results of the lateral group were not as good as those of the medial group. The VAS and Lysholm scores of the combined group were worse than those of the isolated group. With regard to concomitant surgery, ACL reconstruction was most common in the medial group and cartilage procedures in the lateral group.