INFLUENCE OF EARLY VS LATE RETURN TO SPORT ON OUTCOMES IN ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A RETROSPECTIVE COMPARATIVE STUDY

E. Mazzini¹, G. Placella¹, N. Biavardi¹, M. Alessio-Mazzola^2,3, S. Mosca¹ and V. Salini¹

¹Vita-Salute University San Raffaele, Milan;
²Department of Surgical Sciences and Integrated Diagnostic (DISC), University of Genoa, Genoa, Italy;
³IRCCS Orthopaedic Clinic, Policlinic Hospital, San Martino, Genoa, Italy

Correspondence to:
Mattia Alessio Mazzola, MD
Department of Surgical Sciences and Integrated Diagnostic (DISC),
University of Genoa,
Viale Benedetto XV n. 6,
16132 Genova, Italy;
IRCCS Orthopaedic Clinic,
Policlinic Hospital San Martino,
Largo Rosanna Benzi 10,
16132 Genova, Italy
e-mail: mattia.alessio@hotmail.com

Received:  20 March 2022 Accepted: 23 April 2022

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ABSTRACT

The optimal timing for return to sport (RTS) following anterior cruciate ligament (ACL) reconstruction remains controversial. Accelerated rehabilitation protocols may increase the risk of re-injury, whereas delayed RTS could enhance recovery outcomes. To investigate the effects of rehabilitation timelines on functional outcomes and reinjury rates post-ACL reconstruction, comparing standard RTS protocols with delayed RTS approaches. In this retrospective cohort study, 54 highly active athletes aged 15-35 years who underwent primary ACL reconstruction using a hamstring autograft were analyzed. Participants were divided into two groups based on rehabilitation duration: the Standard RTS group (returning to sport within 5-7 months, n=28) following MOON guidelines, and the Delayed RTS group (returning after≥9 months, n=26) adhering to Delaware-Oslo guidelines. Outcomes measured included the Lysholm Knee Score for functional assessment, Tegner Activity Scale (TAS) difference for activity level changes, ACL Return to Sport Index (ACL-RSI) for psychological readiness, and incidence of ACL re-rupture and contralateral ACL injuries over a 30-month follow-up. The Delayed RTS group demonstrated significantly better functional outcomes (Lysholm score: 94.1±4.7 vs 79.6±6.9, p <0.001), smaller reductions in activity levels (TAS difference: -0.33±0.8 vs -1.9 ±0.8, p <0.001), and higher psychological readiness (ACL-RSI: 85.6±13.2 vs 51.9±16.4, p <0.001) compared to the Standard RTS group. The Standard RTS group had a seven-fold increased risk of ACL re-rupture (Relative Risk (RR)=7.0, Odds Ratio (OR)=6.5) and doubled the risk of contralateral ACL injury (RR=2.0, OR=2.17). The combined risk of an ACL injury was significantly higher in the Standard RTS group (RR=3.53, OR=5.27), with an absolute risk increase of 29%. Delaying RTS beyond nine months post-ACL reconstruction significantly improves functional outcomes psychological readiness, and reduces the risk of reinjury compared to standard rehabilitation timelines. These findings support the adoption of extended, criterion-based rehabilitation protocols to optimize patient recovery and enhance long-term knee health.

KEYWORDS: anterior cruciate ligament reconstruction, return to sport, rehabilitation timeline, re-injury risk, functional outcomes, MOON guidelines, Delaware-Oslo guidelines