BLOG: Graft size matters
The world is changing. Orthopedics is changing. We are changing. Now more than ever, we need health, happiness and wellness. We need a space to talk about the things relevant to us and relevant to our patients.
Allow me to introduce a new resource center for Healio Orthopedics: Health, Happiness, Wellness and Women. This new resource center is intended to discuss all things related to orthopedic surgeon health, happiness and wellness, with a special focus on women in orthopedics. Why women, you might ask? Because women and orthopedic issues related to women – whether as a physician or as a patient – are important and deserve to be highlighted. We will have guest bloggers writing about topics important to their practices, to their lives and to their patient population. We may discuss orthopedic problems that impact women disproportionally, such as ACL tears, or challenges specific to women leaders or something else entirely.
I encourage you all to spend a few minutes reading and then let me know your feedback, comments, questions and thoughts. Discuss with your colleagues, residents, fellows and students. Let me know what you think and what topics you would like to see covered. I hope you enjoy this new feature to Healio Orthopedics. As always, stay healthy, stay happy and stay well.
- Rachel M. Frank, MD
Associate professor, department of orthopaedic surgery
University of Colorado School of Medicine
Director of the Joint Preservation Program
University of Colorado
Female patients have a higher risk of ACL tear, a higher risk of retear and a lower chance of returning to sports/activity at the same level.
The orthopedic literature has established that smaller ACL grafts, particularly less than 8 mm have an increased risk of failure. So, why would we ever put a graft of less than 8 mm in anyone? Unfortunately, smaller grafts may be the consequence of a smaller patient. Smaller patients are often young female athletes. As orthopedic surgeons, we need to find ways to avoid smaller grafts. So no matter what graft you choose to use, please consider making it 9 mm or more, especially in female athletes.
Popular graft choices include hamstring, patellar tendon and quadriceps tendon. All of these grafts are excellent choices – as long as they are large enough.
Historically, hamstring grafts have consisted of a doubled semitendinosus and gracilis tendon and have frequently measured less than 8 mm, potentially accounting for the increased failures, especially in female patients. Multiple papers have reported the mean graft diameter of a traditional four-strand hamstring autograft is 7.7 mm to 8.5 mm and graft diameter often correlates with sex, BMI, height and thigh girth. Studies in the biomechanics lab have established that larger graft diameters have greater strength.
A review of some of the more recently published papers examining ACL graft size consistently illustrate that graft size matters. Spragg and colleagues demonstrated that with ACL grafts measuring 7 mm to 9 mm, there was a 0.82 times lower likelihood of needing a revision for every 0.5-mm increase in graft diameter. Similarly, in a larger study of 2,240 patients from the Swedish registry, an increase in graft diameter between 7 mm and 10 mm resulted in in a 0.86 lower likelihood of revision surgery with every 0.5-mm increase.
In 2019, Snaebjörnsson and colleagues reviewed 18,425 patients and reported an increased risk of ACL revisions with hamstring autografts less than 8 mm compared to patients treated with grafts greater than 8 mm. Also, patients with hamstring grafts more than 9mm had a reduced risk of ACL revision compared to patients treated with a patellar tendon autograft. Clatworthy reviewed 1,480 hamstring autograft cases and found grafts at least 7.5 mm had twice the failure rate of grafts of at least 8 mm and for every 1-mm decrease in graft diameter, there was a 45.7% increased risk of failure.
Keeping these studies in mind, not only should we consider the type of graft but the size of the graft. If you prefer to use hamstring autograft, be familiar with several ways to prepare the graft to increase the diameter in smaller harvested tendons. Hamstring tendons can be tripled, quadrupled and even made into a five-string grafts. In most patients, a quadrupled semitendinosus will result in a graft of 9 mm or more.
Quadriceps tendon is becoming a more popular graft choice. The quadriceps tendon provides a robust graft and future clinical studies will allow us to determine if this graft can also help level the sex differences in ACL failures.
For those who prefer to use patellar tendons, remember that when measuring a patellar tendon graft, you are measuring the width of the tendon and not the diameter.
The bottom line is to be cognizant to provide female athletes with a large enough graft – no matter what you use.
Our female athletes deserve better. Graft size matters. If we provide our female athletes with graft sizes of 9 mm or greater, perhaps their risk of retear and their ability to return to competitive sports/activities will be equivalent to male athletes.
My final thoughts are the following:
- Consider graft choice and size with the specific patient in mind, especially female athletes;
- Consider making preoperative measurements/estimates of graft size on MRI;
- Consider a quadriceps tendon graft, which is more robust and thicker than a patellar tendon;
- A quadrupled semitendinosus will almost always provide a 9 mm graft, if not add gracilis; and
- Hamstring tendons can be tripled, quadrupled and even made into a five-strand graft.
There is no excuse for a small graft. Graft size matters, especially for the female athlete.
References:
Clatworthy M. Orthop J Sports Med. 2016;doi:10.1177/2325967116S00082.
Snaebjörnsson T, et al. Am J Sports Med. 2017;doi:10.1177/0363546517704177.
Snaebjörnsson T, et al. J Bone Joint Surg Am. 2019; doi:10.2106/JBJS.18.01467.
Spragg L, et al. Am J Sports Med. 2016;doi:10.1177/0363546516634011.
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