Summary

This study establishes 1-year and 2-year MCID values for patients undergoing ACLR, revealing that a majority achieve significant clinical improvement (69.4-90.9% at 1 year and 70.4-89.2% at 2 years). It highlights that lower BMI, poorer preoperative scores, and meniscal injuries are associated with a higher likelihood of reaching MCID.

Abstract

Introduction

There is growing interest in the orthopaedic literature in analysing outcomes and the minimal clinically important difference (MCID) following anterior cruciate ligament reconstruction (ACLR). This study aims to identify minimally clinically important difference values at 1-year and 2-year postoperatively in patients undergoing anterior cruciate ligament reconstruction and the effect of different preoperative factors in predicting MCID achievement.

Materials And Methods

This study involved 474 patients who underwent ACLR between 2000 and 2022 and were followed up at 1-year and 2-year timepoints. Patients were graded preoperatively and at 1-year and 2-year follow-up using Lysholm, Knee Injury and Osteoarthritis Outcome Score (KOOS) subscale, and Short-Form 36 Physical and Mental component Summary (SF-36 PCS and MCS) scores. MCID was calculated by a distribution method using half the value of the standard deviation of the difference between postoperative and preoperative outcome scores. Univariate and multivariate logistic regression analyses were performed to investigate factors associated with achieving MCID.

Results

Baseline characteristics such as age, gender and BMI were similar in both groups (p>0.05). Characteristics such as lower body mass index, lower preoperative scores and concomitant meniscal injury were associated with a higher chance of achieving MCID. For the Lysholm score, 1-year and 2-year MCID values as well as the percentage of patients who achieved MCID were 9.13 (87.6%) and 9.07 (88.4%) respectively. For KOOS Symptoms: 9.99 (77.8%) and 10.7 (76.8%), KOOS Pain: 9.10 (81.4%) and 9.60 (81.0%), KOOS ADL: 8.44 (86.1%) and 8.70 (81.9%), KOOS Sport: 16.1 (90.9%) and 18.8 (84.0%), KOOS QoL: 14.9 (86.1%) and 16.1 (85.0%). For SF-36 PCS: 4.72 (69.4%) and 4.81 (70.4%) and, SF-36 MCS: 5.90 (89.0%) and 6.02 (89.2%).

Conclusions

This study attained 1-year and 2-year MCID values for ACLR patients in the context of limited local MCID literature, and showed that a majority of patients achieve MCID at 1-year (69.4-90.9%) and 2-year (70.4-89.2%) follow-up postoperatively, confirming the significant clinical benefits of ACLR. Furthermore, factors such as BMI, preoperative score, and meniscal involvement can predict the achievement of MCID.