Which graft is better: patellar tendon or hamstring tendon for an ACL

The two most common areas where a surgeon can take a graft to replace your ACL are the patellar tendon and the hamstring tendon. If this is new information to you, please refer to our previous blog on where the most common areas for an ACL graft are. Also keep in mind that the patellar tendon and hamstring tendon are the most common but not the only sources for an ACL graft.

As you read the differences below, it is important to remember that your surgeon will choose the graft site for your ACL surgery. In some cases, due to a previous injury or surgery, one or more of the graft sites may not be feasible. The good news is that our ACL rehabilitation app, Curovate, has a protocol for hamstring tendon, patellar tendon, quadriceps tendon, allograft, and non-surgical ACL rehabilitation.

Overall, the patellar tendon is the more stable ACL graft and has a lower re-injury rate compared to the hamstring tendon graft. Read the advantages and disadvantages of each graft site in the table below.

Hamstring Graft Surgery (HT)	Patellar tendon surgery, also called bone-patellar-bone surgery (BTB).
1. The surgery takes longer and the tourniquette, a device used during surgery to restrict blood flow in the leg, stays on longer2	1. The knee is stiffer after surgery2
2. The knee moves more freely forward and backward when tested with a KT-1000 Arthrometer machine2a device that measures the forward and backward movement of your lower leg compared to your thigh.	2. Increased knee pain when kneeling on the ground3
3. During a period of 15 years after surgery, more reinjury was reported.3	3. Over a period of 15 years after surgery, increased stiffness and difficulty straightening the knee were reported3.
4. The need to perform another surgery to address problems with the first surgery is called revision surgery. The revision rate for hamstring operations increases by 0.65% within 1 year and by 4.45% within 5 years4.	4. The 1-year revision rate is 0.16% and the 5-year revision rate is 3.03% for patellar tendon graft surgery4.
5. Hamstring muscle strength reduced by 15%1. Muscle strength is the maximum force you can exert in the shortest possible time.
6. Muscle strength decreases by 11% when stretching the knee2. Muscle strength is the amount of force a muscle can produce during maximum effort.
7. There is increased instability in the knee when force is applied to it2. Instability is unwanted movement in a joint.

Conclusion

Based on the research reviewed in this blog, the patellar tendon has a lower re-injury rate and is more stable at 1 and 5 years after ACL surgery. However, the location of the graft should be discussed with your surgeon and ultimately the surgeon will decide the most suitable area for the ACL graft.

If you have had ACL surgery and want clear daily, weekly and monthly guidance for your knee extension and daily exercises for your recovery, try our Cuorvate app. Curovate offers video-guided daily exercises, weekly range of motion goals and exercises, progress tracking, the ability to measure your knee and hip range of motion, and in-app chat with a physical therapist.

If you need more tailored help during your ACL recovery, check out our Virtual Physiotherapy page to book your 1-on-1 video session with a physiotherapist.

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References

1. Ageberg, E., Roos, HP, Silbernagel, KG, Thomeé, R., Roos, EM, akademin, S., Gothenburg University. (2009). Knee extension and flexion muscle strength after anterior cruciate ligament reconstruction with patellar tendon graft or hamstring tendon graft: a cross-sectional comparison 3 years after surgery. Knee Surgery, Sports Traumatology, Arthroscopy, 17(2), 162-169.
2. Beynnon, B.D., Johnson, R.J., Fleming, B.C., Kannus, P., Kaplan, M., Samani, J., and Per Renstrom. (2002). Anterior cruciate ligament replacement: comparison of bone-patellar tendon-bone grafts with two-strand hamstring grafts A prospective, randomized study. The Journal of Bone & Joint Surgery, 84(9), 1503-1513.
3. Leys, T., Salmon, L., Waller, A., Linklater, J., and Pinczewski, L. (2012). Clinical outcomes and risk factors for re-injury 15 years after anterior cruciate ligament reconstruction: a prospective study of hamstring and patellar tendon grafts. The American Journal of Sports Medicine, 40(3), 595-605.
4. Rahr-Wagner, L., Thillemann, T.M., Pedersen, A.B., and Lind, M. (2014). Comparison of hamstring tendon and patellar tendon grafts in anterior cruciate ligament reconstruction in a nationwide population-based cohort study: results from the Danish Knee Ligament Reconstruction Register. The American Journal of Sports Medicine, 42(2), 278-284.