Outcomes of early surgical repair versus conservative management in ACL injuries

Mar 12, 2021 Oklahoma Sooners forward Madi Williams (25) dribbles the ball against Oklahoma State Cowgirls guard Neferatali Notoa (2). Credit: Amy Kontras-USA TODAY Sports

Researchers continue to try to crack the code on the best way to manage a torn anterior cruciate ligament (ACL). In the Netherlands, sports scientists again tackled the issue by randomizing 167 volunteers with a torn ACL to either an immediate surgical repair group or a conservative rehab (with the option to repair after three months) group. The researchers measured primary and secondary outcomes before the intervention and three, six, nine, 12, and 24 months after randomization.

Eighty-five subjects received early ACL reconstruction, while 82 participated in a therapeutic intervention right after injury. Half of the conservative management group opted to undergo surgical reconstruction an average of 10.6 months after inclusion in the study. These 41 participants demonstrated the recommended conditions for reconstruction, namely rotational instability, repeated knee giving out, and a positive pivot-shift test.

The primary outcome measures included the participant’s score on the International Knee Documentation Committee (IKDC) test, which tested the patient’s perception of their knee function and symptoms. The Knee Injury and Osteoarthritis Outcome (KIOO) score, Lysholm score, return to sport status, the incidence of the injured knee giving way, Tegner score, pain rating, and treatment satisfaction score were secondary outcomes.

Results and practical implications

At the initial follow-up three months after randomization, the conservative management group showed a significant improvement in the IKDC scores compared to the surgical group. This trend shifted to favor the reconstruction group at the nine-month follow-up. At the end of the two-year study period, both groups showed improvement in their IKDC scores. However, the reconstruction group showed significantly better progress in this score.

There’s no doubt that the conservative group achieved a better return to functional status in the first few months after injury. That they were not in the acute stage of surgical recovery may account for the initial surge of improved IKDC scores in this group. However, patients who experienced continued knee instability and giving out likely plateaued in their functional improvement. In contrast, those in the repair group continued to make gains at six and nine months after surgery.

The early repair group also showed better secondary outcome scores in the KIOO and the Lysholm tests at the two-year evaluation. Pain scores did not differ significantly between the groups. As should be expected, the surgical group demonstrated significantly fewer incidences of the knee giving way 24 months after randomization. A greater percentage of the repair group participants (43% versus 31%) returned to their prior level of sport. Interestingly, the rates of those subjects satisfied with their treatment were quite high and nearly equal in both groups (92.6% of the surgical group and 91.3% in the conservative group).

Testing the effectiveness of surgical interventions against no intervention is difficult. This study was unique in its access to patients – offering participation to 282 qualified patients. However, only 167 agreed to participate. Subjects were assigned randomly without consideration of which management approach might be best for them. Therefore, half of the conservatively managed patients received later reconstruction because they met the criteria for this approach.

Despite the delay in treatment for those in the conservative group, both groups exhibited high satisfaction ratings two years after the initiation of the study. The later surgery for half of the rehab group may account for their lower outcome scores. With the average surgical delay of 10 months, half of this group was also delayed in their post-op rehab. They might still have decreased function, increased pain, and may not have been ready for return to sport despite the 24 months since their injury. The researchers did not separate out the results of those who were managed conservatively from those who later received surgical repair. Therefore, while an interesting exercise, this study lacks any real clinical relevance except to suggest that guidelines for evaluating the need for surgical repair might effectively predict those who will eventually need surgical intervention.


  1. BMJ 2021;372:n375
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