Debate continues in ACL reconstruction about graft type and technique

Although leaders in the field of ACL reconstruction agree that successful treatment relies on accurate diagnosis, addressing concomitant injuries and understanding anatomy and the patient’s desired activity level, controversy still exists about which graft options and surgical techniques provide the best outcomes.

“Success in ACL reconstruction is [dependent upon] good surgery, addressing everything that is injured and good rehabilitation that is based on function and not time,” American Orthopaedic Society for Sports Medicine President Christopher D. Harner, MD, of the University of Pittsburgh, told Orthopedics Today.

Patient activity level and sports participation are factors used to determine whether surgical or conservative management is needed. Patients involved in highly competitive cutting and pivoting sports can benefit from ACL reconstruction with autograft followed by rehabilitation, Kurt P. Spindler, MD, of Vanderbilt University Medical Center in Nashville, told Orthopedics Today. Conservative treatment consisting of a rehabilitation program may be successful for patients who are reducing their activity levels or those who have no other associated injuries such as a meniscal tear, he said.

For patients who are candidates for surgery, stiffness, articular cartilage pathology, symptomatic instability, pain from meniscal injury and loss of motion affect how patients will be treated. For example, Harner noted it is imperative that meniscal repair, but not removal, is performed in patients with torn menisci as studies have demonstrated inferior outcomes in such cases when the meniscus was not repaired or a meniscectomy was performed. In cases of revision, surgeons take the modes of failure for the original procedure into consideration.

“In more complex and revision cases, better precise analysis and addressing reasons for failure [as well as] consideration given to revising ligament tunnels including bone grafting when necessary, is important,” Nicholas A. Sgaglione, MD, president of the Arthroscopy Association of North America and professor and chairman of the Department of Orthopedics, at North Shore Long Island Jewish Medical Center in Great Neck, N.Y., told Orthopedics Today.

Graft choices

A variety of graft types are available for reconstruction, and patient age, graft processing procedures and whether the reconstruction is a revision case play a role in graft choice and outcomes. For instance, Harner noted the use of allografts in revision cases or high school- or college-age patients have been linked to higher risks for early failure. Sgaglione highlighted that this link is more apparent in cases using irradiated allograft. However, Spindler noted that allografts show failure rates and outcomes more comparable to autograft when used in patients older than 30 years and there is within a 2% difference in failure rates in patients aged 40 years.

“Allograft processing may play a big role,” Peter R. Kurzweil, MD, of Memorial Orthopaedic Surgical Group in Long Beach, Calif., told Orthopedics Today. “It seems when irradiated and chemically sterilized grafts are not used (i.e., only fresh frozen), the results are comparable to autografts.”

Newer autograft choices include quadriceps tendon and synthetics, but graft choice varies according to surgeon preference. Freddie H. Fu, MD, DSc(Hon), DPs(Hon), of the University of Pittsburgh, warns against using synthetic grafts, as they may cause irritation or synovitis. Harner’s first choice is bone-tendon-bone for high-level athletes. His second choice is hamstring autograft for less active patients. He occasionally uses quadriceps tendon autograft in select patients, such as heavy weight wrestlers.

John P. Fulkerson, MD, of Orthopedic Associates of Hartford, P.C., said that he prefers quadriceps tendon autograft, and noted this graft has resulted in less anterior knee pain and shows no evidence of increased failure rates at his institution.

“[There is] increasing information about the efficacy of quadriceps as a free-tendon graft being as reliable as other autograft types with less morbidity,” he told Orthopedics Today.

When allograft is used, Sgaglione noted that physicians should carefully document the company that is the source of the graft, the company’s policy and procedure regarding FDA Good Tissue Practices and whether the company is American Association of Tissue Banks-accredited to ensure quality control. He also counsels patients that the risk of disease transmission exists, but is low, based on those quality practices. “I ask all patients to sign a specific ‘allograft consent’ to document the informed consent discussion,” Sgaglione said.

He noted that the cost of using allograft tissue can be “1,000 times greater” than using autografts. “The other considerations of harvest-site morbidity, less surgical time and overall efficacy and outcomes success must also be weighed,” Sgaglione said.

Single- vs. double-bundle

Although sources for this story said that anatomic single-bundle ACL reconstruction continues to serve as the gold standard, they noted that researchers have yet to compare anatomic single-bundle with anatomic double-bundle ACL reconstruction. In addition, Spindler noted that studies comparing these two techniques have shown no differences in clinical outcomes or patholaxity between single- and double-bundle procedures.

“A good study would be to compare apples to apples,” Sgaglione said. “If they are using single-bundle vs. double-bundle and they are both in the anatomic position, that would probably indicate there is not a big difference.”

However, he noted that single-bundle ACL reconstruction may be better suited for skeletally immature patients or those with smaller footprint or condyles that would need smaller hamstring autografts.

Cases with meniscal loss, failed single-bundle reconstructions, patients who participate in pivot sports or those with instability may be candidates for double-bundle procedures, Sgaglione said. In addition, complex cases with instability may require double-bundle reconstruction to ensure stability in full range of motion, Fulkerson said.

Fu noted that the complex technical aspects of double-bundle reconstruction require a highly skilled surgeon. Double-bundle ACL reconstruction also takes longer to heal, he said, and the posterolateral bundle could retear if placed in the wrong position or tensioned incorrectly.

“You have to look at every patient individually,” he told Orthopedics Today. He considers the size of the ACL in determining which technique to use and measures the structure before and during surgery to ensure anatomic placement.

Double-bundle as a concept

Fu said it is important to see double-bundle ACL reconstruction as a concept rather than a technique. Once he determines the size of the ACL, he calculates the percentage of the ACL that requires reconstruction. Rather than focusing solely on whether to use a single- or double-bundle technique, his goal is to reconstruct between 60% and 80% of the ACL.

“If you do not understand that there are two bundles there, you can get confused,” Fu said. “For example, for years we traditionally placed a single-bundle graft from the posterolateral [PL] position on the tibia to the anteromedial [AM] position on the femur. Now, the concept is such that the AM tunnel on the tibia should be joined to the AM tunnel on the femur. The same goes for the PL tunnels.” He added, “It took me 5 to 10 years to come to this conclusion. It will take me another 5 to 10 years to prove it.”

Anatomic femoral tunnel placement

The surgeons agreed that the tunnels must be placed within the anatomic footprint of the ACL.

“As each knee varies by size and shape, it is not possible to rely on a one-size-fits-all guide,” Kurzweil said. “We like to leave the torn ACL at its femoral and tibial attachments, using these as the anatomic landmark to center the guides.”

The number of tunnels drilled depends on the size of the ACL, Fu said. If the ACL is 14 mm to 18 mm, Fu constructs two to four tunnels. If it is more than 18 mm, he drills four tunnels as part of his double-bundle concept.

Surgeons have come to realize that it is very difficult to reach the correct femoral position using a transtibial technique and have embraced independent ways of drilling tibial tunnels using an AM portal technique, according to Kurzweil and Harner. An AM portal gives the surgeon a broader, 90° view of the lateral wall of the femoral condyle and the native footprint, Sgaglione said.

“When you go through the tibial tunnel, it is difficult to get to that femoral side,” Harner said. “That is called a one-incision or transtibial technique. The more you try to get to the femoral insertion, the more you are compromising your tibial tunnel. Then when you drill your tibial tunnel, you are often blowing out or making the tibial tunnel bigger, so a lot of surgeons switched over to a medial portal technique.”

Spindler alternatively advises referencing the femoral tunnel off the back wall and referencing the tibial tunnel off the anterior part of the lateral meniscus.

“Look at the K-wire on the tibial side, and use the mini fluoroscopic unit,” Harner said. “It is the one that the hand surgeons use that has low-dose radiation. The surgeon himself or herself does the imaging, and it takes 30 to 45 seconds to image the K-wire and 20 seconds on the femoral side.”

Another cause for early failure is when patients return to sport too soon, Harner said. Sgaglione said many groups have published studies that report that up to only 50% of patients return to preinjury functional activity levels. For football and soccer, Spindler noted that Multicenter Orthopaedic Outcomes Network (MOON) data published in 2012 showed that about 70% of patients returned to their respective sports.

“Many patients come in and feel that success after ACL surgery is pretty much a guarantee based on the media and based on the professional sports. The perception is that basically everyone comes back,” Sgaglione said.

Fu and Harner noted significantly higher failure rates in patients returning to play 6 months and 7 months after reconstruction. As a result, Harner and his colleagues at the University of Pittsburgh base return to play on function rather than a set time to resume sports.

“Instead of saying you are ready between 4 and 6 months, we now do these specific functional tests to determine if the athlete has the strength and balance to progress to further athletic activities,” he said.

The tests include strengthening, balance and flexibility exercises. Patients must pass four levels of testing before they are permitted to return to sports. Some patients return between 8 months and 10 months, but many do not regain strength and balance and may take longer, Harner said.

“They are not only endangering their operative leg, but when they go back and they are not ready, they are favoring their good leg, the uninvolved extremity,” he said. “There is a high incidence of injury to the contralateral knee in these patients. A number of studies have shown a significantly higher ACL injury to the contralateral limb for athletes going back too soon.”

Surgical skill is key

Sgaglione and Spindler agree that surgeons should be able to perform many types of reconstruction techniques.

“Number one, is to understand the strengths and weaknesses of your individual technique that you use, whether it is two-incision, transtibial or endoscopic,” Spindler told Orthopedics Today. “I think you need to be able to do more than one of those techniques. In case plan A does not work, you can have plan B.”

Sgaglione suggested that if surgeons do not perform at least one ACL surgery per month, to pick one technique that is reproducible “in your hands.” He recommends not leaving the operating room until secure fixation and knee stability is established because “if stability is not reached at the end of the case, it is not going to evolve and become more stable.”

“I think [surgeons must have] a great understanding of the anatomy and function of the ACL,” Fulkerson said. “Take a look at cadaver knees. I think every surgeon should take the opportunity to take courses.”

Evidence-based medicine

Spindler, Sgaglione, Fulkerson and Kurzweil recommended that surgeons keep abreast of evidence-based research such as findings from the Multicenter ACL Revision Study (MARS) and MOON. Recent studies using the MOON cohort revealed allografts have shorter longevity than autografts, Fulkerson said.

“Evidence-based medicine is helpful to prove and disprove whether certain techniques are best or better,” Sgaglione said. “Certain people feel that allografts are equivalent and, in fact, the data may show that is not the case. You will not get that information from anecdotal analysis.”

Fu warns that objective data is as important as evidence-based studies. Not all evidence-based studies provide good data, he said. For instance, the data may be older and no longer relevant. If the study shows the ACL in the wrong position, “it does not mean anything,” Fu said.

“Many of the older studies looking at long-term outcomes were done with surgeries that we would consider nonanatomic by today’s standards,” Kurzweil said. “The recent understanding of anatomic ACL reconstructions has been in practice for a few years, so long-term outcomes have yet to be investigated.” – by Renee Blisard Buddle

Do you prefer to use allograft or autograft for ACL reconstruction and why?

Autograft is perferable

I have been doing ACL reconstructions for the past 40 years. In my opinion, I prefer to use autografts for primary ACL reconstruction. Allografts have a role in multiligament reconstructions and some revision cases but, due to higher failure rate in young athletic patients, my preference is to use autografts as the first choice in young athletic patients.

My choice is to use bone-tendon-bone (BTB) for the young, pivotal elite athlete, the single harvest semitendinosus (quad bundle all-inside) for the recreational athlete, and allograft or quadriceps tendon for revisions.

Graft choice should be individualized for the athlete based on age, gender, sports and level of participation. The surgeon should also consider the donor site morbidity, return to play, length of rehab and the fixation options.

We have several choices of autografts, patellar tendon (BTB), hamstrings and the quadriceps tendon. Meta-analysis by Yunes showed a higher rate of return to sport with BTB. Verma showed longer graft failure with BTB. Prodromos showed that four-bundle hamstrings had equal stability as BTB with better fixation. A systematic review by Rheinhardt showed more hamstring graft failure, 15%, compared to BTB, 7%. Barrett reported a 24% failure rate with allograft in teenage athletes. NFL team physicians used BTB in 99% of players. Ardern reported only 50% return to Australian rules football with quadriceps bundle hamstring grafts.

This is a summary of the pros and cons of autografts vs. allografts:

Autografts

Pro

Con

• Harvest-site morbidity
• Anterior knee pain with BTB harvest
• Knee flexion weakness with double-hamstring harvest
• Higher failure rate of hamstrings in young patients
• Longer incorporation into the tunnels
• Low return to sport with hamstring double-tendon harvest due to knee flexion weakness

Allografts

Pro

• Unlimited tissue for multiligament reconstruction
• Shorter operating room time as there is no harvest time
• Less morbidity due to harvest of grafts

Con

• Potential for disease transmission. When I started, we did not know about hepatitis C. What about hepatitis D, E, F, etc.?
• Cost
• Higher failure rate in younger patients – 24%
• Availability
• Longer time to incorporate into the tunnels
• Unpredictable strength due to radiation and age of donor

Donald H. Johnson, MD, FRCS(C), is director of the Sports Medicine Clinic at Carleton University in Ottawa, Canada, and is Section Editor for the Arthroscopy section of Orthopedics Today.
Disclosures: Johnson is a consultant for Arthrex and Piramal and receives book royalties from Springer, Elsevier, Lippincott and WoltersKluwer.