When considering revision anterior cruciate ligament (ACL) surgery, several factors should be carefully evaluated:

1. Cause of Primary ACL Failure: Understanding why the initial ACL surgery failed is crucial. Common reasons include improper placement of tunnels, graft failure, inadequate rehabilitation, or traumatic reinjury.
2. Patient’s Anatomy and Biomechanics: Assessing the patient’s knee anatomy, bone alignment, laxity, and any associated injuries (e.g., meniscal tears, cartilage damage) is essential.
3. Graft Choice: The choice of graft depends on several factors, including:
   – Patient’s Age and Activity Level: Younger and more active patients may benefit from stronger grafts.  There are several studies that suggest autograft (taking a graft from oneself) is better and has a lower retear rate than allograft (donated cadaver tissue).
   – Previous Graft Choice and Outcome:  If the previous graft type is known, consideration of an alternative type is necessary.  There are multiple choices including a patellar tendon graft, hamstring graft or quadriceps tendon graft.  One can also take a graft from the opposite leg.  
4. Tunnel Positioning and Sizing: Accurate tunnel placement is critical to restore knee stability and function. This may require adjustments based on previous tunnel positions and any anatomical changes.  In some cases the tunnel needs to be grafted
5. Rehabilitation Protocol: Tailoring the rehabilitation program based on previous outcomes and any new findings from the revision surgery is important for optimizing recovery and preventing re-injury.  It is important to note that return to sports can take 9+ months and people who return early or who don’t have documented return of strength and stability have an increase chance to retear.
6. Surgeon’s Experience: Revision ACL surgery can be more challenging than primary ACL reconstruction due to altered anatomy, scar tissue, and potential tunnel overlap. Choosing a surgeon experienced in revision procedures is advisable.

The MARS study (Multicenter ACL Revision Study) was a comprehensive, multicenter study conducted in the United States to evaluate outcomes following revision anterior cruciate ligament (ACL) reconstruction surgery. It involved multiple sites and aimed to gather data on a large cohort of patients undergoing revision ACL surgery to understand the factors influencing outcomes and to identify predictors of success or failure.

Key Findings and Conclusions from the MARS Study:

1. Graft Choice: The study found that graft choice significantly influenced outcomes in revision ACL surgery. Specifically, autografts (such as hamstring tendon and bone-patellar tendon-bone grafts) were associated with better outcomes compared to allografts (cadaveric donor grafts). Autografts showed lower failure rates and better functional outcomes.
2. Age and Activity Level: Younger patients and those with higher activity levels tended to have better outcomes following revision ACL surgery. This is consistent with the findings from primary ACL reconstructions, where younger age and higher activity level correlate with better graft survival and functional outcomes.
3. Factors Influencing Outcomes: The study identified several factors that could influence the success of revision ACL surgery, including:
   – Previous graft type and history of graft failure.
    – Associated injuries (e.g., meniscal tears, cartilage damage) and their management during revision surgery.
   – Surgical technique, including proper tunnel placement and graft fixation methods.
   – Rehabilitation protocols and compliance.
4. Complications: The MARS study also highlighted the potential for complications in revision ACL surgery, such as graft failure, persistent instability, and the need for further surgical interventions. These complications underscored the complexity of revision ACL cases and the importance of careful patient selection and surgical planning.

Clinical Implications:

The findings from the MARS study have influenced clinical practice in several ways:

– Orthopedic surgeons now consider autografts as the preferred choice for revision ACL surgery when feasible, given their superior outcomes compared to allografts.

– Patient selection criteria have become more refined, emphasizing the importance of age, activity level, and previous surgical history in predicting outcomes.

– Continued research and refinement of surgical techniques and rehabilitation protocols aim to further improve outcomes in revision ACL surgery.

At Total Orthopedics and Sports Medicine we have experts with knowledge and experience in ACL revision surgery. Contact us today to explore your treatment options.