In Belgium, most patients undergo surgery when they have an ACL rupture. There is namely a general belief that ACL reconstruction is necessary to restore mechanical knee stability, and that ACL surgery is necessary to return to sports safely, but also to avoid long-term disadvantages such as persistent knee instability, re-injury and PTOA.

Only 2 RCTs compared the clinical effectiveness between ACL reconstruction and conservative treatment (= rehabilitation + optional delayed surgery) for acute ACL ruptures: the KANON trial, the COMPARE trial and the ACL SNNAP trial. The KANON trial concluded that a strategy of early reconstruction plus rehabilitation did not provide better results at five years than a strategy of initial rehabilitation with optional delayed ACL reconstruction. The COMPARE trial found slightly better self-reported outcomes (knee symptoms, self-reported knee function, and perception of the ability to participate in sports) in the immediate ACL reconstruction group compared with the conservative group at two-year follow-up. However, none of these findings were considered clinically important.

Based on the results of the KANON trial and the COMPARE trial one can conclude that conservative management with optional delayed surgery does not result in inferior clinical outcomes compared to immediate ACL reconstruction on a population level.

However, on the level of the individual patient, large between-subject differences were found. In the KANON trial, 39% of the ACL patients in the conservative treatment group showed persistent knee instability requiring delayed surgery during the two-year follow-up, this percentage has grown to 51% at the five-year follow-up. The COMPARE trial reported that 50% of the ACL patients in the conservative group required delayed surgery in the two years follow-up. In this group of patients, time to return-to-sport is extended, and longer sick leave times are observed because surgery is delayed compared to patients undergoing immediate ACL reconstruction. Hence, early identification of patients who would benefit from early ACL reconstruction, or on the contrary, from rehabilitation alone, is crucial to reduce resource consumption and decrease irrelevant overtreatment. It is hypothesized that treatment success relies on clinical factors (such as knee function and MRI features) as well as the quality of rehabilitation, and psychological factors such as expectations, fear of re-injury and locus of control.

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The main aims of this RCT are therefore:

1. to compare the clinical effectiveness of both treatment options and as such verify the existing literature

2. to assess which patient-specific factors predict successful outcomes after conservative treatment of ACL injuries.

 

Status of the study

 

Pilot study

• A pilot study was performed in UZ Leuven and CHU Liege to investigate the feasibility of recruiting patients for this RCT.  The study protocol of this pilot study was published in BMJ: https://bmjopen.bmj.com/content/bmjopen/12/3/e055349.full.pdf

• The results of this pilot study will be published in 2024.

• This trial was registered on ClinicalTrials.gov (NCT04408690) on 29 May 2020.

Full study

• In Q1 of 2023 the pilot study progressed to a full study. Since then, 3 other hospitals joined the IODA study (Jessa Ziekenhuis Hasselt, UZ Brussel, St Luc Bouge).

• The protocol will be published in 2024.

• This trial was registered on ClinicalTrials.gov (NCT05747079) in February 2023.