Summary

We documented a high rate of meniscal healing and no progression of cartilage degeneration and subchondral bone abnormalities with short-term MRI follow-up; however, there was worsening of meniscus extrusion, even in the immediate post-operative period.

Abstract

Background

Prospective studies evaluating second look imaging of meniscus root repair using a transtibial pullout technique are limited; therefore, optimal surgical indications and technique for meniscus root repair remain uncertain.

Hypothesis/Purpose: We hypothesized a high rate of healing, improvement in meniscus extrusion and prevention of articular cartilage degeneration and subchondral bone abnormalities following meniscus root repair.

Study Design: Prospective cohort study; Level of evidence, 3.

Methods

Consecutive patients undergoing transtibial root repair were prospectively enrolled at two orthopedic centers between March 2017 and January 2019. Pre- and post-operative MRIs were reviewed by a musculoskeletal radiologist in a blinded fashion for meniscus healing, quantification of extrusion, articular cartilage grade, subchondral bone changes, and coronary/meniscotibial ligament abnormalities. Given persistent extrusion observed on post-operative MRIs, an additional 10 patients were consented and enrolled for immediate (before weight-bearing) post-operative MRIs.

Results

45 patients (16 M: 29F) with an average age of 42.3 (SD 12.9) and BMI of 31.6 who underwent 47 meniscal root repairs (29 medial, 16 lateral, 2 had both) were prospectively enrolled in the study. Post-operative MRI was obtained on average 6.3 months following surgery (range 5.1-8 months). 98% of meniscus repairs had evidence of healing. Mean extrusion increased from an average of 1.94mm (± 1.52) pre-operatively to 2.62mm (± 1.44) post-operatively (p = 0.03). There was no significant progression of chondromalacia grade, subchondral edema, insufficiency fracture, subchondral cysts, or subchondral collapse. In the additional 10 patient cohort, the mean pre-operative extrusion increased from 1.64mm (± 1.19) to 2.0mm (± 0.98) post-operatively (p=0.23).

Conclusions

Prospective MRI analysis of transtibial meniscus root repair confirms a high rate of meniscal healing and no observable progression of cartilage degeneration or subchondral bone abnormalities at short-term follow-up. However, meniscus extrusion worsens, even in the immediate post-operative period. Additional studies should evaluate techniques to improve meniscus extrusionare warranted to optimize meniscal root fixation techniques to decrease post-operative meniscal extrusion.

Keywords: meniscus; meniscus root; meniscus extrusion; meniscal tear; transtibial pullout repair; prospective cohort