Issue: November 2016
November 01, 2016
10 min read

Options for nonoperative treatment of ACL injuries exist, but remain controversial

Issue: November 2016
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Each year, there are an estimated 200,000 ACL injuries in the United States. Proper management of these injuries is crucial for future function. The gold standard treatment is reconstruction, especially if the patient is young and active. Often these athletes are assured they will return to their pre-injury activity levels. However, the evidence may not validate that thinking.

“There are a lot of scientific articles, [and] there are a lot of talks on the topic and experts’ opinions saying that if you want to return to sports, you need an ACL reconstruction,” Richard B. Frobell, PhD, of the Department of Orthopaedics at Lund University in Lund, Sweden, told Orthopaedics Today Europe. “The problem is that there is little evidence to support that.”

Patients have come to believe this idea: 98% of athletes think a return to pre-injury activity level is possible, according to Lynn Synder-Mackler, PT, ATC, ScD, SCS, FAPTA, professor in the Department of Physical Therapy at the University of Delaware in Newark, Del., USA. However, the literature shows 55% to 65% of athletes with ACL injuries return to sports, she said.

Richard B. Frobell
Richard B. Frobell

That does not mean ACL reconstruction is not a viable treatment option, she noted.

“I am not advocating that young, active people not undergo ACL reconstruction,” Snyder-Mackler said. “I am advocating that they know what they are getting themselves into.”

Although the reconstruction procedure achieves good results, reconstruction has its pitfalls. Patients undergoing reconstruction are at risk for osteoarthritis (OA) — about 75% will develop OA 15-years post-reconstruction — but they are largely unaware, according to Snyder-Mackler. “Roughly, 98% of individuals who are undergoing ACL reconstruction believe they have no or only a little higher risk for any OA,” she said. “We are not doing a good job of presenting this information.”

The good news is not every patient with an ACL tear needs reconstruction — conservative treatment options exist. For instance, some patients obtain good results after ACL repair while others respond well to nonoperative treatment.

In this Cover Story, experts discuss the conservative management of ACL injuries and how these compare with reconstruction. The experts also provide tips on how to decide which patients should get which treatment.

Lynn Synder-Mackler
Lynn Synder-Mackler

Rehabilitation as first-line treatment

Recent studies have demonstrated that orthopaedic surgeons should consider rehabilitation as a first-line approach for ACL tears. Frobell and colleagues conducted a randomized controlled trial of 121 young, active adults with an acute ACL tear to a previously uninjured knee. In one arm, 62 patients underwent early ACL reconstruction performed within 6 weeks of randomization. The remaining 59 patients were assigned to the delayed reconstruction group, which started with a course of rehabilitation.

“We showed that after 2 years, both groups were comparable in all outcomes,” Frobell said. Both groups had similar results for quality of life, function and return to sports. At 5 years, the results were the same. The researchers are preparing their 10-year follow-up data for publication. Those results mirror those of the first two studies, with little loss to follow-up, according to Frobell.

Frobell said starting with rehabilitation is a thoughtful approach to ACL tear management because it allows the surgeon to treat symptoms. If the patient is still feeling unstable after 2 to 3 months of rehabilitation, reconstruction would then be appropriate.

“You need to know if you have symptoms in order to know if you need surgery,” Frobell said.

Snyder-Mackler and colleagues’ research supports these findings. In a prospective cohort study that included 300 patients — 150 patients each in Norway and the United States — they followed 143 patients with an ACL injury. They noted few differences between nonsurgical and surgical groups. There were no significant differences in patient-reported knee function or muscle strength.


Patients opt for just rehab

“Our cohort in the United States and Norway also suggest that when people are given a few more weeks of progressive rehabilitation, or prehab, to figure out how their knees are functioning, about a third of them decided not to have reconstruction,” Snyder-Mackler said. However, the patients who pursued this option were mostly athletes older than 25 years, she noted.

There are questions about an athlete’s ability to return to sports participation without reconstruction, with many thinking nonoperative treatment comes up short in this regard. However, Snyder-Mackler and colleagues found no significant differences in level 1 and higher level 2 sports participation between surgically and nonsurgically treated patients. These findings showed offering progressive rehabilitation as a first-line treatment is a smart choice.

“It is prudent and evidence-based right now to do a little bit more rehabilitation first, that is progressive, not just ‘Go lay on that bed and I will put ice on your knee,’” Snyder-Mackler told Orthopaedics Today Europe. The rehabilitation program should include progressive strengthening and neuromuscular training, she said.

“We all need to do better,” Snyder-Mackler said. “We need to do better rehab. We have some new evidence out that just a short, progressive preoperative rehabilitation increases the positive outcome and return-to-sports rate significantly, over usual care.”

Even if patients eventually move on to surgery, the rehabilitation program will have benefits and help produce optimal surgical results. The prehab protocol can improve the muscle strength, coordination and motion that was affected by the injury, according to Krzysztof Ficek, MD, a sports medicine specialist at Galen-Orthopaedics in Bierun, Poland.

The rehabilitation program should improve active stabilization, using kinesthetic techniques, he noted.

Hostile healing environment

Historically, orthopaedists believed a torn ACL lacked the ability to heal. In some of his early work on the subject, Freddie H. Fu, MD, DSc(Hon), DPs(Hon), professor and chair of orthopaedic surgery at the University of Pittsburgh Schools of Health Sciences, said he found that after an ACL tear “a whole biological cascade of things happen that create an unfriendly environment for the healing that occurs inside the joint.”

When surgeons attempted to repair these injuries many years ago, the results were often poor, Fu noted.

Freddie H. Fu
Freddie H. Fu

In more recent research, Fu and colleagues found stem cells in the ACL, which are probably present for daily function and maintenance.

“I think with the stem cells in mind, we can potentially turn it into a friendlier environment,” which could help with repair and healing, Fu told Orthopaedics Today Europe.

A new repair technique has demonstrated promising early results in this area, according to research results. The bridge-enhanced ACL repair (BEAR) technique, developed by Martha Murray, MD, of Boston, represents a new direct ACL repair technique that harnesses the body’s healing potential.

The BEAR technique overcomes a major obstacle of reconstruction: the lack of complex structure. “[Reconstruction is] always just an approximation,” Lyle J. Micheli, MD, director of the Sports Medicine Division at Boston Children’s Hospital, told Orthopaedics Today Europe. “It does not have the complexity of structure that the real ACL does, being [that] the ACL has at least two major bundles that rotate around each other as they turn. We cannot reproduce that with the grafting we put in there.”

According to Micheli, potential candidates for BEAR are arthroscopically assessed.

Lyle J. Micheli
Lyle J. Micheli

“We have to have at least half of the ACL still present in the knee on the tibial side,” said Micheli, who is the orthopaedic surgeon involved in the trials for BEAR.

During the procedure, the surgeon stitches the ACL remnant into drill holes located at the approximate spot of the ACL insertion, according to Micheli. Then, the surgeon inserts a sponge, which is a semi-rigid disc of bioenhanced material, in the gap between the torn end of the ACL and the femoral insertion site. Four heavy sutures provide temporary stability during the several weeks it takes the area to heal.


Postoperatively, all patients wore a brace and used crutches for 6 weeks, according to Micheli. They also performed physical therapy.

“We generally let them start back to a jogging program at 12 weeks,” he said. At 6 months, the researchers tested quadriceps and hamstring strength as well as stability, Micheli noted.

Replicates the ACL

The phase 1 trial included 10 patients in the BEAR group and 10 patients in the reconstruction group.

“There were no adverse effects from the implant,” Micheli said. The researchers have received U.S. Food and Drug Administration approval for a phase 2 study that will include 100 patients.

“The MRIs we are seeing, the follow-up MRIs, it looks like an ACL,” Micheli said. “The same exact position and so forth. If we can reproduce the ACL in this way, I think it will be a game changer.”

Fu, who is an Orthopaedics Today Europe Editorial Board member, said although the BEAR technique looks promising, it is too early to recommend it for common use.

“They should do more cases before we can recommend people to repair in a common manner,” he said. “People should explore it.”

However, currently, “[the] traditional graft is still the more reliable way to do it,” Fu said.

There are other repair techniques under investigation. Primary ACL repair with internal brace augmentation is one approach that may have some promise, according to Donald C. Fithian, MD, an orthopaedic surgeon at Southern California Kaiser Permanente in El Cajon, Calif., USA. An internal brace is a synthetic ribbon used to support the ACL as it heals, he said.

A case series which included 27 patients treated with the internal brace and was conducted in Scotland by MacKay and colleagues demonstrated that, in the short-term, the internal device restored stability and function as well as traditional reconstruction. Patient-reported outcomes were similar to those for reconstruction that have already been published. The researchers hope these pilot data will be used to develop a randomized controlled trial that compares the internal brace and reconstruction.

Donald C. Fithian
Donald C. Fithian

In 2015, Eggli and colleagues reported their results with another repair technique, which uses dynamic intraligamentary stabilization (DIS) to preserve the injured ACL and promote healing. Findings from a 10-patient trial showed DIS produced stable clinical and radiological healing in all but one patient.

The most common ACL repair technique uses fibers from the natural ligament, according to Ficek. “It has been found that despite the destruction of the natural ligament after rupture, it is still a good source of receptors, which communicate the sensation of motion,” he said. “This aspect is then introduced into rehabilitation protocols.”

To operate or not

In Ficek’s experience, nonsurgical treatment is used when the patient has contraindications to surgery. Some patients will simply refuse surgery after the prehabilitation because the protocol successfully improved the quality of motion and muscle strength enough to satisfy the patient. But, most patients will eventually require surgery, according to Ficek.

Krzysztof Ficek

“I am an orthopaedic surgeon, so I believe proper diagnostic protocols and surgery are better for the patient,” he said.

When contemplating treatment options, Fu told Orthopaedics Today Europe he always considers two possibilities. First, if the injury produces daily functional problems for the patient, such as regular knee buckling, that patient should be managed with reconstruction. Second, if the patient is willing make an activity change, he or she can pursue nonoperative treatment.

“I have an ACL tear,” Fu said. “I [changed] my lifestyle so that in 15 years, I only buckled once. I did it during a wedding, doing a ‘twist-and-shout’ dance. I just swim, bicycle, exercise on a treadmill. My lifestyle is maintained, and I am fine.”

Fu’s own ACL tear aside, his treatment decision is based on patient input, so he typically spends 30 minutes to 60 minutes with new patients educating them.


“The better educated they are, probably the better they are in terms of outcomes and follow-up, too,” he said.

Younger patients are more aggressive

Fu finds his younger, athletic patients tend to be more aggressive and consequently, are more likely to have surgery.

“If they have surgery, they should be prepared to take a whole year off, at least, before they can return,” Fu said.

Older patients are more likely to switch activities to avoid surgery, he said.

Ficek generally chooses repair for pediatric cases. “Nowadays, techniques involve sewing of the detached fragment of ligament — mostly its tibial part — to its attachment — also, mostly the tibial part with the bony fragment,” he said.

According to Fu, surgeons must be cautious operating on children 8 years to 10 years old who have ACL injuries.

“If the growth plates are still open and if those kids are still so young, and they are still growing; then you be more careful about surgery,” he said. “Many times, I tend to wait until they finish growing before I operate. When the growth plate is open during surgery, you may damage the growth plate and potentially harm the ligament or make it crooked.”

Consider activity level

Fithian feels patient activity is a significant factor in the decision to operate or not. Patients with low activity levels are good candidates for nonsurgical treatment.

“The function of the ACL prevents the tibia from subluxating anteriorly on the femur,” he said. “But if all of your activities are slow, controlled activities not requiring jumping and pivoting, you can sometimes go a whole lifetime without getting it reconstructed.”

In Fithian’s practice, patients get reconstruction if they meet any of the following parameters:

  • They are at risk for further knee injury, specifically to the meniscus;
  • They have failed a trial of nonoperative treatment; or
  • They have symptoms with activity.

Knee stability is a critical factor in the decision to operate, according to Fithian. If a patient has an unstable-looking partial ACL tear, Fithian will apply a load to the knee and check for displacement. If a patient has 3 mm or more displacement, they are at increased risk for further injury, which makes the patient a good candidate for surgery.

On a continuum

How to manage ACL injuries is not an all-or-nothing proposition, Snyder-Mackler said.

“This is a continuum: Not advocating nonoperative treatment for everybody or operative management for everybody, but giving them a little time to choose,” she said.

“We need to end the story about having one group of individuals strongly advocating that we should not perform ACL surgery at all and another group of individuals saying that everyone needs an ACL reconstruction,” Frobell said. “Because the truth is probably in the middle.”

It is clear some patients benefit from reconstruction while others do well with conservative treatment, he said.

“We need to investigate who these individuals are,” Frobell said. “The best way to find out who these individuals are is to start clinical trials where we start treatment with rehabilitation and follow patients closely to find factors that relate to the success of rehabilitation and the need for surgical stabilization.” – by Colleen Owens

Disclosures: Ficek, Fithian, Frobell, Fu, Micheli and Snyder-Mackler report no relevant financial disclosures.