Summary

The risk of meniscus repair failure is increased when a staged procedure is chosen for an ACL-deficient knee, particularly in medial meniscus interventions and among females.

Abstract

Purpose

To investigate the failure rate, predictive factors associated with failure and clinical outcomes
after a two-stage surgery; meniscus repair followed by subsequent anterior cruciate ligament
(ACL) reconstruction (ACLR).

Methods

Patients with a concomitant meniscus and ACL injury who underwent a two-stage surgery
between January 2015 and January 2021 were identified. The primary outcome was meniscal
repair failure, defined as a reoperation (re-repair or resection). A Cox-regression analysis was
used in order to analyze factors associated with meniscal repair failure within 3 years after the
primary surgery for a meniscal repair. Secondary outcomes were range of motion (ROM),
anterior knee laxity and the Knee Injury and Osteoarthritis Outcome Score (KOOS) at 1 and 2
years, follow-up. The thresholds of Patient Acceptable Symptom State (PASS), Treatment
Failure (TF), Minimum Important Change (MIC) were applied to KOOS4 (mean score of the
KOOS Pain, Symptoms, Sports/Rec and QoL subscales).

Results

A total of 150 patients were included. The meniscal repair failure rate after 3 years was 36.7%.
Failure of meniscal repair was significantly associated with a time interval >1 year between the
meniscal repair to the ACLR (HR 2.5; 95% CI 1.2-5.5; P<0.01), medial meniscus repair (HR 2.3;
95% CI 1.6-3.4; P<0.01), and female sex (HR 1.42; 95% CI 1.0-1.9; P=0.01). The age of the
patient was not associated with meniscal repair failure. At the 6-month follow-up, most patients
(72.5%) showed less than 2mm of knee laxity; 4 patients (6.7%) experienced loss of extension
and 4 patients (1.7%) experienced loss of flexion. On the KOOS4, at the 2-year follow-up, PASS
was achieved in 53.4%, TF occurred in 1.7%, and MIC was reached in 36.4% of patients.
Meniscal repair failure it did not have a negative impact on objective and subjective outcomes.

Conclusion

A longer time interval from meniscal repair to ACLR, medial meniscus repair, and female sex
were associated with an increased risk of meniscal repair failure. Even though a high failure rate
of 36.7% was seen, it did not have a negative impact on objective and subjective outcomes.