Comparison of medial and lateral meniscal transplantation with regard to extrusion of the allograft, and its correlation with clinical outcome

Abstract

We compared extrusion of the allograft after medial and lateral meniscal allograft transplantation and examined the correlation between the extent of extrusion and the clinical outcome. A total of 73 lateral and 26 medial meniscus allografts were evaluated by MRI at a mean of 32 months (24 to 59) in 99 patients (67 men, 32 women) with a mean age of 35 years (21 to 52). The absolute values and the proportional widths of extruded menisci as a percentage were measured in coronal images that showed maximum extrusion. Functional assessments were performed using Lysholm scores. The mean extrusion was 4.7 mm (1.8 to 7.7) for lateral menisci and 2.9 mm (1.2 to 6.5) for medial menisci (p < 0.001), and the mean percentage extrusions were 52.0% (23.8% to 81.8%) and 31.2% (11.6% to 63.4%), respectively (p < 0.001). Mean Lysholm scores increased significantly from 49.0 (10 to 83) pre-operatively to 86.6 (33 to 99) at final follow-up for lateral menisci (p = 0.001) and from 50.9 (15 to 88) to 88.3 (32 to 100) for medial menisci (p < 0.001). The final mean Lysholm scores were similar in the two groups (p = 0.312). Furthermore, Lysholm scores were not found to be correlated with degree of extrusion (p = 0.242). Thus, transplanted lateral menisci extrude more significantly than transplanted medial menisci. However, the clinical outcome after meniscal transplantation was not found to be adversely affected by extrusion of the allograft.

An Osteophyte in the Tibial Plateau Is a Risk Factor for Allograft Extrusion After Meniscus Allograft Transplantation

“…In previously reported studies, however, medial transplanted menisci were less extruded than lateral transplanted menisci. 15 We believe that our results have little bias because the nonexcision group had more MMATs than the excision group but showed more extrusion. Finally, osteophyte excision was not randomized, but it was initiated at a certain time point, which may induce selection bias.…”

Meniscus tear surgery and meniscus replacement

“…Open surgery is associated with less meniscal extrusion. Yoon et al 218 found more graft extrusion in the medial group on MRI, but Koh et al 219 observed that transplanted lateral menisci extruded more significantly than transplanted medial menisci. However, the clinical outcome after MAT was not found to be adversely affected by extrusion of the allograft.…”

Meniscal transplantation: state of the art

“…Some aspects of the surgical technique, such as the way the graft is implanted and fixed (namely, soft tissue vs bony fixation),26 the type of allograft (medial vs lateral)68 and the sizing method,69 have been looked at. In a prospective series of 88 MATs comparing soft tissue fixation versus bony fixation, Abat el al 26 found a higher percentage of extruded meniscal tissue in the soft tissue fixation group.…”

“…This suggested the superiority of bony fixation in terms of limiting extrusion. Koh et al 68 evaluated a series of 73 lateral and 26 medial meniscus allografts by means of MRI at a mean follow-up of 32 months. Their results showed that lateral MAT extrudes significantly more than the medial MAT.…”