Knee Grafting Procedure in the Greater San Francisco Bay Area
There are a number of choices of graft material available to the orthopedic surgeon who performs ACL reconstruction surgery to repair a torn or ruptured anterior cruciate ligament. When considering which option is best for you, many factors are taken into consideration. This includes your age, activity level, history of prior knee pain or injury, your size, and your rehabilitation potential. It is important to realize that research has not yet determined the “best” ACL graft.
Graft options at Muir Orthopaedic Specialists include:
- Patellar Tendon Graft
- Hamstring Tendon Graft
- Patellar Tendon Allograft
Remember that every knee is unique and that every option may not be right for you. This review of graft choices is presented to give you, the patient, to help you gain an understanding of the pros and cons of using some of these various tissue options for ACL reconstruction. We want you to feel comfortable with your choice – after all, it is your knee and you deserve the best possible outcome.
Patellar Tendon Graft
The Patellar tendon graft or bone-tendon-bone (BTB) has been the gold standard choice for ACL reconstruction since it was popularized in the 1980s. It has been used extensively and has consistently demonstrated excellent surgical outcomes with a 90-95 percent success rate in terms of returning patients to their pre-injury levels of activity.
The patellar tendon originates at the base of your patella (kneecap) inserts on your tibia (shin bone) several inches below your knee cap. A 10 mm wide section (or middle 1/3) of your patellar tendon with 25mm bone blocks from the tibial tubercle and outer portion of the patella form the graft which becomes your “new” ACL. This graft is passed thru bone tunnels and secured with headless screws to lock it in place. This method offers excellent fixation of the graft and allows for early rehabilitation. The potential for rupture of the remaining patellar tendon or fracture of the patella is extremely low.
Drawbacks of Patellar Tendon Graft
This “gold standard” graft isn’t perfect, however. There may be more pain associated with this donor site than with any other graft choice. This sometimes results in greater initial atrophy (muscle wasting) of the quadriceps (thigh) muscle compared to the other two options. The scar is also longer and may be sensitive for patients that kneel a lot.
The biggest issue, however, is the increased incidence of anterior or patello-femoral knee pain that may persist. This makes patients with a history of chronic patello-femoral pain or arthritis, patellar tendonitis or petite individuals with narrow patellar tendons, poor candidates for this graft option. This option is best for fit, athletic and motivated individuals who will rehabilitate appropriately in order to minimize the risk of a suboptimal result.
Hamstring Tendon Graft
There are several variations of hamstring tendon grafts in terms of the actual tissue used. At MOS, we are currently using a doubled (folded over) combined semitendinosus and gracilis tendon graft (DTSG) because it provides the strongest tensile strength. This graft is sometimes referred to as a “quad” graft as there are actually 4 strands in the final product. There has been a surge of interest in the use of the hamstring tendon graft due in part to improvements in how the graft is held in place. Many sports medicine surgeons now use this graft exclusively as their “graft of choice”.
This procedure requires a smaller incision and usually has less surgical pain from harvesting the graft. Thus, the initial post-operative period is easier and more comfortable with this option. Also, because there is no violation of the patellar tendon, there seems to be a lower incidence of anterior knee pain and due to the position and size of the incision, fewer problems with kneeling.
Drawbacks of Hamstring Tendon Graft
Once again, there is no such thing as the perfect graft. Although the fixation techniques are quite good, it is not as predictable as the patellar tendon. Patients with recurrent hamstring strains should be cautioned to avoid this technique. This technique may result in a slight loss of hamstring strength of up to 10%. For most patients, this is not a concern unless they are involved in a sport that entails a lot of hamstring related strength activities i.e. backwards running such as a defensive back in football. This procedure is great for athletes especially women, or petite individuals that do not want an allograft or patients with a history of patellar tendonitis or anterior knee pain.
Which Is Better, Hamstring or Patellar Tendon?
Studies that evaluate the results of patellar tendon versus hamstring tendon grafts in ACL reconstruction, for the most part, indicate comparable results in terms of successfully stabilizing the knee. At this point, the literature does not show that one of these graft choices is “better” than the other. The main issue for the patient is which tissue is best donated or which graft has the least implication for that individual in terms of having it removed in the first place. With that said, let’s consider an option that alleviates the issue of donor site problems.
Patellar Tendon Allograft
An allograft refers to a graft that is not taken from your body but instead from a deceased individual. The advantages of using a cadaver graft include no pain, scars, or risks at the donor site. Surgical time is quicker and because there is less discomfort postoperatively, the incidence of joint stiffness and atrophy of the leg muscles is significantly reduced.
Allografts are a good choice for patients ages 35 and up, those patients undergoing ACL revision surgery, or patients desiring a less invasive surgery to allow for a more rapid return to work. This graft option combines the optimal fixation of the patellar tendon with the rehabilitation program and decreased patellar dysfunction of the hamstring graft- possibly the best of both worlds.
Drawbacks of Patellar Tendon Allograft
As with all options, this graft is not without its faults. The biggest concern with allografts is the risk of contracting a serious infection such as HIV or hepatitis. Currently, the risk of these infections is 1 in 1.5 million procedures. Unlike organ transplants, allografts are usually not at risk for tissue rejection. The other concern with this graft is the potential for long term “play” or stretch of the graft after 5-10 years as there have been some studies that have found measurable but not clinically or statistically significant changes in these grafts.
If this procedure is of interest to you and you would like more information, please contact our office. We have locations in Walnut Creek, San Ramon, Brentwood, and Concord.
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