Conceptual illustration representing ACL reconstruction timing.

ACL Reconstruction: Is Delaying Surgery Really Better?

Mira Elwood in Health & Wellness November 2025 • 4 min read.

"A new study questions the long-held belief that delaying ACL reconstruction leads to better outcomes, challenging conventional wisdom in sports medicine."

Anterior cruciate ligament (ACL) injuries are a common and often devastating occurrence for athletes and active individuals. For years, the standard approach has been to delay surgical reconstruction of the ACL to allow for swelling to subside and range of motion to return. This approach was rooted in the belief that operating on an inflamed knee could lead to stiffness and other complications.

However, recent research is beginning to challenge this conventional wisdom. A study presented at the 2016 Combined Australian Knee Society and New Zealand Knee & Sport Society Meeting investigated whether there were significant differences in outcomes between patients who underwent acute (early) ACL reconstruction versus those who had delayed surgery. The results may surprise you.

This article delves into the key findings of this study, exploring the implications for athletes, active individuals, and the orthopedic surgeons who treat them. We'll break down the research in an easy-to-understand way, providing insights into whether delaying ACL reconstruction is truly the best course of action.

Challenging the Status Quo: Acute vs. Delayed Reconstruction

Conceptual illustration representing ACL reconstruction timing.

The study, titled "Results Are Similar Two Years After Acute or Delayed Anterior Cruciate Ligament Reconstruction. A Randomized Controlled Trial," aimed to assess the impact of the timing of ACL reconstruction on patient outcomes. Researchers randomized 70 patients with acute ACL injuries, all with a high recreational activity level (Tegner ≥6), into two groups: one undergoing acute reconstruction within 8 days of the injury, and the other undergoing delayed reconstruction 6-10 weeks after the injury, once normalized ROM was achieved.

The primary endpoint of the study was range of motion (ROM) at three months post-surgery. What's interesting is that the study found no significant difference in ROM between the two groups at this point. Moreover, after two years of follow-up, the researchers observed similar outcomes in both groups across a variety of measures, including:

Lysholm score
KOOS values
VAS scores (measuring knee function and impact on activity level)
Functional strength (one leg hop index >90%)

Specifically, the Lysholm score was 87 in both groups, KOOS values showed no significant difference and the VAS response to the question "How is your knee working on a scale from 0-100? (100 = best)" was 81 in the acute group and 71 in the delayed group. The functional strength (one leg hop index >90%) was 85% in the acute group and 67% in the delayed group. These findings suggest that early ACL reconstruction doesn't compromise functional outcomes compared to delayed surgery.

Rethinking ACL Reconstruction Timelines

The study's conclusion is particularly noteworthy: "We found no increased risk of arthrofibrosis after acute ACLR. Good results can be achieved at two years regardless of ROM and swelling in the acute stage." This challenges the traditional approach of delaying surgery and suggests that early reconstruction may be a viable option for many patients. While further research is always warranted, these findings provide valuable insights for athletes, active individuals, and orthopedic surgeons alike, potentially paving the way for more individualized treatment plans.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1177/2325967117s00174, Alternate LINK

Title: Results Are Similar Two Years After Acute Or Delayed Anterior Cruciate Ligament Reconstruction. A Randomized Controlled Trial

Subject: Orthopedics and Sports Medicine

Journal: Orthopaedic Journal of Sports Medicine

Publisher: SAGE Publications

Authors: Karl Eriksson, Christoffer Von Essen, Björn Barenius

Published: 2017-05-01

Everything You Need To Know

What were the two ACL reconstruction timing strategies compared in the study, and how did the study design differentiate between these strategies?

The study compared "acute" ACL reconstruction (within 8 days of injury) with "delayed" reconstruction (6-10 weeks after injury, once normalized ROM was achieved). It randomized 70 patients with acute ACL injuries, all with a high recreational activity level (Tegner ≥6), into these two groups to assess the impact of timing on patient outcomes. The research focused on range of motion (ROM) and other measures to determine if early surgery compromised functional outcomes compared to the traditional delayed approach.

What were the key outcome measures assessed in the study, and what did the results reveal about the differences between acute and delayed ACL reconstruction?

The study's findings indicated no significant difference in range of motion (ROM) between the acute and delayed ACL reconstruction groups at three months post-surgery. After two years, both groups showed similar outcomes in Lysholm scores, KOOS values, VAS scores, and functional strength (one leg hop index >90%). Specifically, the Lysholm score was 87 in both groups, KOOS values showed no significant difference and the VAS response to the question "How is your knee working on a scale from 0-100? (100 = best)" was 81 in the acute group and 71 in the delayed group. The functional strength (one leg hop index >90%) was 85% in the acute group and 67% in the delayed group. This suggests early surgery doesn't necessarily lead to worse outcomes.

Could you explain what Lysholm score, KOOS values, VAS scores, and one leg hop index >90% each measure in the context of ACL reconstruction outcomes?

Lysholm score measures knee function, with higher scores indicating better function. KOOS values (Knee injury and Osteoarthritis Outcome Score) assess various aspects of knee health and function, including pain, symptoms, daily living activities, sport and recreation function, and quality of life. VAS scores (Visual Analog Scale) in the study measured patient-perceived knee function on a scale from 0-100. The one leg hop index >90% assesses functional strength and stability of the knee. All these metrics provide a comprehensive evaluation of the outcomes following ACL reconstruction.

In what ways do the study's findings challenge conventional wisdom regarding the timing of ACL reconstruction?

The study challenges the long-held belief that delaying ACL reconstruction is always better. The finding that good results can be achieved at two years regardless of ROM and swelling in the acute stage suggests that early ACL reconstruction may be a viable option. This challenges the traditional approach of delaying surgery to allow swelling to subside and range of motion to return. It suggests the potential for more individualized treatment plans based on patient-specific factors rather than a one-size-fits-all delayed approach.

What additional research is needed to further refine our understanding of ACL reconstruction timing and optimize patient outcomes?

While the study provides valuable insights, more extensive research is needed to validate these findings across diverse patient populations and longer follow-up periods. Future studies could investigate the ideal timing of ACL reconstruction based on individual patient characteristics, injury severity, and specific rehabilitation protocols. Additionally, research could explore the potential benefits of combining early ACL reconstruction with accelerated rehabilitation programs to optimize patient outcomes and return to activity levels. Further investigation into the risk factors associated with each approach will help refine treatment strategies.