Purpose

While statistical significance is important in interpreting the results of various interventions, it is also important to investigate the role of clinically significant outcomes, or differences in outcomes that are felt to make a positive difference by patients. These values may include the minimal clinically important difference (MCID), and patient acceptable symptom state (PASS). The purpose of this review was to summarize the factors predicting the achievement of the patient acceptable symptom state (PASS), minimal clinically important difference (MCID) and related measures for common patient reported outcome measures (PROMs) following anterior cruciate ligament reconstruction (ACLR).

Methods

Three databases (MEDLINE, PubMed and EMBASE) were searched from inception to January 5, 2024. The authors adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Revised Assessment of Multiple Systematic Reviews (R-AMSTAR) guidelines and Cochrane Handbook for Systematic Reviews of Interventions. Data on demographics, PROMs, predictive factors, statistical associations, and statistical modeling were extracted. Associations between predictive factors and MCID or PASS were recorded in the form of odds ratios (OR), with p-values less than 0.05 considered as significant.

Results

Thirteen studies comprising 21,235 patients were included (48.1% female). The mean age at ACLR was 29.3 years (range of means: 26.7-48.5). Eight studies comprising 3,857 patients reported on factors predicting the PASS. Significant predictive factors for achievement included concomitant lateral extra-articular tenodesis (OR = 11.08, p=0.01), hamstring tendon (HT) autografts (OR range: 2.02-2.63, p≤0.011), age over 30 (OR range: 1.37-2.28, p≤0.02), male sex and/or gender (OR range: 1.03-1.32, p≤0.01), higher preoperative PROMs (OR range: 1.04-1.21). Increased symptom duration decreased achievement of PASS (OR range: 0.15-0.71, P≤0.007). Eight studies comprising 18,069 patients reported on factors predicting the MCID. Factors reducing the likelihood of achieving the MCID included female sex (OR = 0.93, p=0.034), absence of HT autografts (OR = 0.70, p<0.0001), higher preoperative PROMs (OR = 0.76-0.84, p≤0.01), meniscectomy regardless of meniscus repair (OR = 0.67, p=0.014), and collision or traumatic mechanism of injury (OR = 0.02-0.60, p≤0.05).

Conclusion

Higher preoperative PROMs, age over 30, male sex, concomitant lateral extra-articular tenodesis, and HT autografts were significant factors influencing PASS achievement. Lower preoperative PROMs, male sex, atraumatic injuries, and lack of meniscectomies (regardless of meniscus repair) were significant predictors of MCID achievement.