Surgical technique a hot topic in ACL reconstruction

Since Robert Adams offered the first description of a clinical case of ACL rupture in 1837, the ACL has stimulated much research, controversy and debate about the optimal treatment. The debates have remained relatively unchanged in recent years. Surgeons still argue about the surgical approach and graft choices for ACL reconstruction.

In the 19th century, research focused on describing cruciate function and deciding whether the best management was nonoperative or operative treatment, according to a history of ACL deficiency written by Oliver S. Schindler. The 20th century saw the surgeons focused more on the surgical technique.

“In the 1970s, there was a little war between the Americans and the Europeans,” Giancarlo Puddu, MD, an orthopaedic surgeon in Rome, told Orthopaedics Today Europe. “In Europe, they were already reconstructing the ACL with patellar tendon. In the States, on the contrary, they were doing only peripheral reconstructions. There were two different philosophies.”

At the time, surgeons also disagreed on which grafts to choose.

“The material to make an ACL reconstruction since the beginning was divided into two families,” Puddu said. “One, the more popular autologous patellar tendon; the second were the hamstring tendons.”

Image: Randelli P

“Then the discussion has been between old physicians like me and the new generation. We were and still now we are doing the reconstruction using a lateral second incision to be more anatomic. However, almost all the younger surgeons continue to use a single incision. Both techniques were carried out with the help of a scope,” said Puddu, who is an Orthopaedics Today Europe Editorial Board member.

By the mid-1980s, nearly all orthopaedic surgeons performed ACL reconstruction through the arthroscope, he said.

All surgeons can agree on one point: The goal of ACL reconstruction is restore knee function and kinematics, according to Freddie H. Fu, MD, DSc(Hon), DPs(Hon), professor of orthopaedic surgery and chairman of the department of orthopaedic surgery at the University of Pittsburgh School of Medicine, in Pittsburgh.

“We achieve the short-term goals by doing the surgery and getting people back to playing sports,” he said. “The long-term goal is that we can hopefully, prevent the knee from developing osteoarthritis.”

To do that, the surgeon must restore knee kinematics while avoiding excessive anterior-posterior translation and rotation instability. “We want to avoid pivoting that is too excessive,” Pietro Randelli, MD, research professor at the University of Milan and chief of the second department of orthopaedics at Policlinico Sandonato IRCCS in Milan, Italy, said.

With the standard ACL reconstruction technique, surgeons did not attempt to restore the native anatomy. While the traditional surgery achieved good results, patients usually returned to their sports activities, radiographic evidence revealed degenerative changes in up to 90% of patients, according to studies from Donald C. Fithian, MD, and Susan L. Keays, MD.

Research from Yunes and colleagues showed 10% to 30% of patients have pain and residual instability after traditional single-bundle ACL reconstruction. A meta-analysis by D.J. Biau and colleagues indicated only 60% of patients will fully recover after ACL reconstruction.

This led to the biggest trend of the last decade: the shift to anatomic reconstruction, which is “functional restoration of the ACL to its native dimensions, collagen orientation and insertion sites,” said Fu, who is an Orthopaedics Today Europe Editorial Board member.

The goal of anatomic reconstruction is to reproduce 60% to 80% of the native insertion site, he said.

“An anatomic reconstruction places the ACL at the site of the native footprint on both the tibial and femoral sides,” Fu said. “It is also important to reproduce the native tensioning pattern of the ligament during fixation of the graft.”

Clinical results show anatomical procedures are superior. In a randomized control trial of 281 cases with 3-year to 5-year follow up, Mohsen Hussein and colleagues found anatomic double-bundle ACL reconstruction was significantly better than traditional single-bundle procedure and better than anatomic single-bundle reconstruction. Anatomic single-bundle reconstruction was better than the traditional procedure. These small differences may not be clinically relevant.

While many surgeons agree anatomic reconstruction is appropriate, not everyone agrees on the surgical technique. Some support use of a single-bundle reconstruction while others opt for a double-bundle procedure.

In Norway, the preference is for anatomic single-bundle reconstruction, according to Knut Andreas Fjeldsgaard, MD, head of orthopaedic trauma at Haukeland University Hospital in Bergen, Norway. The procedure is indicated in any patient with an unstable knee, he said.

The procedure can offer good stability while being technically easier than double-bundle.

“We know [with] a single bundle in an anatomical position on the femur, that means a more lateral position on the femur, we can have enough stability without any statistically significant difference from a biomechanical point of view,” Randelli said. “If we translate these results and we go look for clinical data, we know single-bundle anatomical construction can arrive at the same stability as a double-bundle reconstruction. We have several randomized trials that demonstrate that.”

Fu individualizes each of his cases to single- or double-bundle based on the size of the insertion site, as well as other criteria, including notch size. The cases in which he performs a single-bundle reconstruction include the following criteria:

• A native insertion site smaller than 14 mm;
• An open growth plate;
• Severe arthritic changes;
• Multiple knee ligament injuries;
• Severe bone bruises; and
• A narrow intercondylar notch.

“Double bundle is a concept and should guide our understanding in all ACL cases, whether single- or double-bundle, as well as augmentation or revision surgeries,” Fu said.

One indication for double-bundle reconstruction is when the length of the tibial insertion exceeds 14 mm, although this is dependent on other factors, such as notch size, femoral insertion site size, etc., according to Fu. With the double-bundle technique, there must be sufficient time for the reconstructed bundles to heal together, which is required for synergistic function, he said.

“This is also applicable in partial tear cases where only one bundle of the ACL is reconstructed and the other is left intact,” Fu said. “The bundles must heal together to function optimally. Above all, though, it should be emphasized that it is better to do a good single-bundle reconstruction than a poor double-bundle reconstruction.”

Some physicians are concerned about the technically challenging double-bundle leading to more surgical errors. “Somebody was saying ‘double bundle, double error’ because in reality if you do two different things in one knee the technique will be more difficult and you can get more errors. A second problem is that after a double-bundle reconstruction the revision is more difficult,” Puddu said.

Whichever technique is used, the surgeon’s ability is critical to the outcome, according to Puddu. “The quality of the results depends not only on the technique you use, but also on the quality of the surgeon’s hands,” he said. “ACL reconstruction results are highly correlated to the capability of the surgeon.”

There are many graft materials available for ACL reconstruction, and the choice of graft can be influenced by age, gender, activity level and type of sport, said Puddu, who prefers bone-patellar tendon-bone in athletes, especially soccer, rugby and football players, and uses hamstring grafts in basketball, volleyball and handball players, as well as in middle-aged patients girls.

While more readily available, allograft has some drawbacks.

“We know that [with] allograft there is limited survivorship,” said Randelli, who is an Orthopaedics Today Europe Editorial Board member. “Allograft provide less donor site morbidity because you take advantage of a cadaver. But in mid-term, 5-year follow-up, the percentage of re-rupture is higher than in autograft. In my primary cases, I do not use and I do not suggest other surgeons use allograft, even in professional sports players.”

However, allograft is often the first choice in revision cases, according to Puddu.

Autografts are more popular in Europe. For example, Norwegian surgeons primarily use autograft, except in the case of multiligament injuries, Fjeldsgaard said. “It is the culture in Norway,”

Autograft is indicated in simple cases, where only an ACL reconstruction is necessary, Puddu said.

“If you are dealing with a difficult revision, if you are dealing with a multiple ligament injury, ACL, PCL and periphery, you must use allograft simply because you cannot take out from the knee all of that material,” he said.

The two most common autograft options are bone-patellar tendon-bone and hamstring grafts, Puddu said.

“In general, bone-patellar tendon-bone autograft is viewed as the gold standard due to its bone-to-bone healing potential on both ends,” Fu said. “Hamstring autograft is popular among females given its cosmesis; however, in some cases, it may be necessary to add allograft to increase the size of the hamstring graft.”

In Sweden, about 98% of orthopaedic surgeons use hamstring grafts, according to Fjeldsgaard. But in Norway, the bone-patellar tendon bone is beginning to be popular again.

Results of a population-based study using data from the Norwegian Knee Ligament Reconstruction Registry, co-authored by Fjeldsgaard, showed hamstring grafts were associated with an increased risk of revision compared with patellar tendon grafts, particularly in the first postoperative year.

Another option is the quadriceps tendon graft.

“Quadriceps tendon is becoming increasingly utilized, is the largest autograft available and can be used for both single- and double-bundle reconstruction,” Fu said.

What is important is that orthopaedic surgeons tailor the graft choice to the patient.

“If you have, for example, a football player, I think we would recommend using bone-patellar tendon-bone grafts,” Fjeldsgaard said, because it is stronger.

At Fu’s institution, graft selection is based on the patient’s specific anatomy. Preoperatively, the surgeon measures the thickness of the quadriceps and patellar tendons with sagittal MRI.

“We also measure the size of the tibial insertion site preoperatively, which is one variable that is taken into consideration during graft choice,” Fu said.

There are many options when it comes to fixation; however, there is not enough data to determine which method is the best, according to Fjeldsgaard. Surgeons at his hospital generally use extra canal devices such as the Endobutton (Smith & Nephew; Memphis, USA) and interference screws in the tibia.

With a patellar-tendon graft, surgeons can use screws, Randelli said. “That is my favorite option on the tibia,” he said, and poly-L-lactic acid (PLLA) screws have largely been abandoned.

“PLLA screws can create huge inflammation with bone resorption and cystic lesions with clear difficulties in revision surgery,” he said. “Some of these fixation systems do not disappear even after a long time (more than 5 years). Actually, the tricalcium phosphate screws are safe and should replace all poly-l-lactide-polyglycolide fixation systems.”

Regardless of fixation technique, the surgeon must be sure his or her choice has been rigorously tested before clinical use, Fu said. “When in doubt,” he said, “keep it simple and use what is proven scientifically.”

The future of ACL research is wide open. More studies will identify which technique is superior — single-bundle or double-bundle, according to the sources for this article.

“In the far future, I see the possibility to work with stem cells to improve the quality of fixation or possibly to improve graft incorporation,” Randelli said.

“There is no end in sight for ACL research,” Fu said. “It is an exciting time in which we still have much to learn and are making strides every day to improve our understanding. While we know anatomic ACL reconstruction closely restores knee biomechanics when compared to the intact knee, it is still unknown what percent of the ACL is required to potentiate optimal function. It may be 50%, 80%, 90%, but further work must be done to develop an understanding.” – by Colleen Owens

• References:
• Biau DJ. Clin Orthop Relat Res. 2007;458:180-187.
• Fithian DC. Am J Sports Med. 2005;33:335-346.
• Fu FH. Anatomic ACL reconstruction — a changing paradigm. Retrieved from http://www.upmcphysicianresources.com/cme-course/anatomic-acl-reconstruction-a-changing-paradigm.
• Fu FH. Anatomic single- and double-bundle anterior cruciate ligament reconstruction. Patient information hand-out and postoperative instructions. Retrieved from: http://ortho.medicine.pitt.edu/content/DoubleBundle.htm.
• Hussein M. Am J Sports Med. 2012;doi:10.1177/0363546511426416.
• Keays SL. Am J Sports Med. 2010;doi:10.1177/0363546509350914.
• Rahr-Wagner L. Am J Sports Med. 2014;doi:10.1177/0363546513509220.
• Schindler OS. Knee Surg Sports Traumatol Arthrosc. 2012;doi:10.1007/s00167-011-1756-x.
• Yunes M. Arthroscopy. 2001;17:248-257.

• For more information:
• Knut Andreas Fjeldsgaard, MD, can be reached at Jonas Lies vei 65, 5021 Bergen, Norway; email: knut.andreas.fjeldsgaard@helse-bergen.no.
• Freddie H. Fu, MD, DSc(Hon), DPs(Hon), can be reached at 200 Lothrop St., Pittsburgh, PA 15213, USA; email: ffu@upmc.edu.
• Giancarlo Puddu, MD, can be reached at Clinica Valle Giulia, via G. De Notaris 2B00197 Rome, Italy; email: puddugiancarlo@gmail.com.
• Pietro Randelli, MD, can be reached at Università degli Studi di Milano, IRCCS Policlinico San Donato, Milan, Italy; email: pietro.randelli@unimi.it.

Disclosures: Fjeldsgaard, Fu, Puddu and Randelli have no relevant financial disclosures.

Do you typically prefer to use single-bundle or multiple-bundle grafts for ACL reconstruction?

Single-bundle is a reasonable option

In the last 10 years, many surgeons have rediscovered the ACL anatomy. Freddie Fu and our Japanese colleagues emphasized the individual anatomy and promoted the double-bundle technique. Simultaneously, Moises Cohen, MD, of Brazil, and Robert Smigielski, MD, of Poland, respectively described the crescent moon tibial insertion and the Ruban theory. The flat bone-patellar tendon-bone and the quad grafts allow for an anatomical reconstruction.

Biomechanically, the role of the different fibers of the ACL does not seem be equivalent. During the latest meeting of the ACL study group in Capetown, South Africa, A. Amis and A. Pearle showed that a small percentage of the ACL fibers may play a major role. So to reproduce the entire footprint insertion is still a matter of debate.

A single-bundle ACL reconstruction (ACLR) is technically easier to perform than a double-bundle ACLR.

Clinically, there is no evidence that a double-bundle ACLR is superior to a single-bundle ACLR, which may be because there is no tool to assess precisely the residual laxity.

In my opinion, to reconstruct with one single bundle taking into account the anatomy is a reasonable option in most of the situations we have to deal with. When required, the surgeon must consider how to treat the associated meniscal, cartilage or peripheral ligament lesions. This is my approach. On the other hand, it is critical that some expert knee teams continue to investigate the double-bundle ACLR option.

Philippe Neyret, MD, is at Centre A Trillat in Lyon, France. He is an Orthopaedics Today Europe Editorial Board member.
Disclosure: Neyret receives reimbursement from Smith & Nephew for travel each year and receives royalties from Tornier for knee implants.

No evidence of better patient outcomes

I use a single-bundle technique for all ACL reconstructions, both primary and revision. Although double-bundle techniques may better reproduce the anatomy and biomechanics of the native ACL under laboratory conditions, the evidence to date does not indicate a benefit in terms of patient outcomes.

The use of a double-bundle technique has diminished dramatically in recent years. This reflects a number of factors, including the lack of a clinically significant benefit, the technical difficulties of performing the surgery, a potentially difficult revision surgery, and a possibly higher graft rupture rate compared to single-bundle techniques.

Although the popularity of double techniques has waned, discussions around the technique have resulted in many surgeons re-evaluating their tunnel positions, particularly on the femoral side. As a result, there has been a shift away from transtibial drilling of the femoral tunnel to drilling via an anteromedial portal. Outside-in drilling has also been re-visited and retro-drilling techniques were developed. But concerns about increased rupture rates with a more “anatomical” placement of the graft have resulted in the concept of isometricity being reconsidered.

One of the potential roles for double-bundle reconstruction was to better control tibial rotation, both in primary and revision settings. An alternative strategy is to use a lateral extra-articular tenodesis and this has been gaining popularity, fuelled by the recent attention paid to the anterolateral ligament.

In short, well-placed single-bundle reconstructions work well for the majority of patients. Additional stability may be provided by a lateral extra-articular tenodesis. On this basis, I see little place for double-bundle procedures.

Julian A. Feller, MBBS, FRACS, is an orthopaedic surgeon at OrthoSport Victoria, in Richmond, Victoria, Australia.
Disclosure: Feller received institutional support from and has been an invited speaker for Smith & Nephew. He is a consultant for Tornier and Stryker.