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Surgery and Rehabilitation For ACL Injuries

Donald Shelbourne pioneered the contralateral ACL reconstruction for torn anterior cruciate ligaments and developed the accelerated ACL reconstruction rehabilitation protocol. Here he outlines the changes that have taken place in the surgical treatment and rehabilitation of ACL injuries over the past 20 years, and explains what the latest thoughts on this injury are today.

What are the factors that contribute to arthrofibrosis following ACL reconstruction and which measures can counteract this?

“We define arthrofibrosis as any symptomatic loss of extension or flexion in the knee. Arthrofibrosis is a condition that can be prevented in almost all cases. Certainly, it is easier to prevent than it is to treat. One of the main factors causing arthrofibrosis is inadequate preoperative rehabilitation before undergoing ACL reconstruction.

“ACL reconstruction is always an elective surgery, except when the lateral structures are torn, which occurs in less than 1% of patients. Every patient should undergo preoperative rehabilitation to regain full extension and flexion equal to the non-injured leg before undergoing surgery. Furthermore, patients should regain good leg control, have a normal gait, and knee swelling should be resolved. In other words, the knee needs to feel like a normal knee, except for the ACL deficiency, before the patient should undergo ACL reconstruction.

“What is important to recognize is that full extension should include hyperextension (full straightening of the knee), not just to 0° extension. Most people have some degree of hyperextension in their knees. To evaluate knee extension, have the patient lie supine, place one hand above the knee to stabilize the femur (thigh), and use the other hand to lift the heel of the foot off the table so the knee goes into hyperextension. This method allows the evaluator not only to appreciate any difference in extension between knees but also feel any subtle tightness in the joint.

“During surgery, the surgeon should put the knee through full range of motion after the graft has been secured as a means to ensure that the placement and fixation of the graft has not captured the joint.

“After surgery, obtaining full range of motion symmetrical to the normal knee should be the top priority for rehabilitation. The key to achieving full range of motion is to be able to prevent and limit a hemarthrosis (bleeding within a joint) in the knee. I use a Cryo/Cuff (Aircast, Inc.) to obtain both compression and cold on the knee after surgery. The patients use a continuous passive motion machine (CPM) mainly as a means to provide elevation with gentle motion. Furthermore, patients stay in the hospital for a 23-hour stay so we can prevent the hemarthrosis and provide patient education.

“As another means to prevent a hemarthrosis, we have our patients remain at bed rest for the first 5 days after surgery. The patients are able to perform their knee range of motion exercises while in bed. Only gentle strengthening exercises are included as part of the rehabilitation program until the patient has achieved full symmetrical extension and knee flexion. When the patients do begin strengthening exercises, they are reminded to evaluate their range of motion daily to make sure they have not lost any extension or flexion. Aggressive strengthening stimulates the ACL graft to mature and can sometimes affect range of motion if the patient does not continue to monitor and perform full extension and flexion exercises daily.

“If these preoperative and postoperative principles are applied, arthrofibrosis can be prevented.”

You have pioneered the use of the contralateral patella tendon as a graft for ACL reconstruction. Why do you prefer this technique over hamstring tendon grafts or allografts?

“In my opinion, ACL reconstruction should be performed using the graft source that has been found to be the most reliable for obtaining good postoperative stability. The patellar tendon graft is the strongest graft available, and it provides quick bone-to-bone healing to allow accelerated rehabilitation. The surgical technique I use involves button fixation, which provides a tight bone-to-bone press fit of the bone plugs, and healing has been evident on MRIs at 1 week after surgery.

“The reason other graft sources have been sought by some surgeons is because of the limited knowledge regarding the means for rehabilitation the donor site. Rehabilitation for ACL reconstruction has always centered upon rehabilitation as it pertains to the ACL graft in the knee, but the donor site has been largely ignored.

“I have always used the contralateral patellar tendon graft for revision ACL reconstruction. In my experience with these patients, I have observed the ease and quickness the patients had with obtaining full range of motion and with returning to activities. At first, it did not make sense to me that patients who were undergoing a revision surgery actually had an easier time with rehabilitation than patients who had primary surgery. I thought the reason was probably because the patients had been through the procedure before, so they knew what to expect. However, range of motion in the contralateral donor knee returned to full essentially on the day of surgery. In addition, the range of motion in the ACL reconstructed knee returned to full quicker also. Furthermore, the attainment of full range of motion seemed to be easy for patients in that they did not have to spend a lot of time each day doing range of motion exercises.

“It was these observations with patients undergoing revision ACL reconstruction that led me to performing primary ACL reconstruction using the contralateral patellar tendon. It took us a couple years to refine the rehabilitation for this approach to surgery. We finally learned that to rehabilitate the donor site, it needed to be done in 3 progressive steps:

  • Step 1
    Get full range of motion in the knee (obtained usually on the day of surgery).
  • Step 2
    Do high repetition, low resistance exercises beginning immediately after surgery to stimulate the patellar tendon to grow back to normal size.
  • Step 3
    Begin heavier strengthening exercises to regain strength back to normal. You cannot begin heavy strengthening until the patellar tendon size has recovered. Heavy strengthening on a smaller than normal tendon makes the tendon extremely sore. The high repetition, low resistance should make the tendon just sore enough so the patient can feel the soreness, but it should resolve quickly after icing the knee.

“Meanwhile, the rehabilitation for the ACL-reconstructed knee can concentrate fully on regaining full range of motion, and there is no immediate concern for strengthening the leg. Full extension should be obtained the day of surgery. Usually flexion will be around 115° at 1 week, 125° at 2 weeks, and full by 1 month postoperatively. By full flexion, I mean the patients should be able to sit on his heels.

“During this first month, the patients should be able to get the patellar tendon size back to normal in the donor knee. So, at 1 month post-op, the patient should be ready to do more aggressive strengthening. By having surgery in both knees, the patient is forced to use both knees equally, which fosters more symmetry between knees. This is an advantage to having just one knee undergo surgery because many times, with 100% strength in one leg and 60% strength in the other leg, the patient continues to favor the stronger leg and the operative leg never recovers to normal. With using the contralateral graft, both knees have symmetrical but lesser than normal strength initially, but by using both legs with every day activities and with strengthening exercises, both will recover to their preoperative normal baseline strength.”

Your stated rehabilitation period following ACL reconstruction using contralateral patellar tendon grafting is three months. What are the limiting factors and, consequently, do you think that three months will be the fastest possible return time to sports without becoming unsafe?

“On average, it takes about 3 months before patients return to competitive sports. They do, however, return to competitive type drills long before that. I do not believe that patients are unsafe with weak legs. In fact, the weakness appears to be protective for reinjury. Because of the initial weakness, most patients will not be able to perform their sport at a level that will cause them to injure their knee. They will not be running and cutting directions hard enough or jumping high enough to cause injury.

“If going back to sports when their leg is weak is unsafe, then I would have been seeing many graft ruptures early in the postoperative period. Instead, the reinjuries have occurred anywhere from 6 months to 10 years after surgery, with the mean time around 3 years. Patients report to us that it takes about 3 to 6 months of actually playing their sport before they feel that they have returned to their previous level of competition.

“Although I do not believe that there is an early time when it is unsafe to return, I do believe that the limiting factor for returning to normal is our ability to rehabilitate the donor site. Using the contralateral patellar tendon graft has allowed us to understand this process better and has allowed patients to achieve symmetrical strength and range of motion back to the preoperative level. I have not found a down side for using the contralateral patellar tendon graft. There are many critics who say, ‘How could you think about taking the graft for a normal knee!’ My answer is, ‘How could you think about taking the graft from the same knee given that many patients never regain symmetrical strength or range of motion between knees?'”

Female athletes appear to suffer a higher incidence of ACL ruptures than males. What are the reasons for this?

“To answer this question, you first have to understand how and when ACL tears occur. ACL tears usually occur during competitive situations, not when the athlete is doing solo activities. Typically, the athlete is hurt when reacting to an unexpected situation. Sometimes it is when the athlete is planting his or her foot to change directions or is landing from a jump. Whatever the circumstances, the athlete mistimes the foot plant, and the forces generated across the knee joint causes the ACL to tear.

“Research has shown that women, on average, have smaller ACLs than men. Therefore, given the same forces, a smaller ACL would be more likely to tear. Interestingly, in my ACL-reconstructed patients, who all receive a 10mm wide ACL graft, there is no difference in the ACL graft tear rate between men and women after surgery, even in a group of highly competitive athletes who returned to their respective sports.

“Unfortunately, this factor of ACL size is not something that can be changed. There are many types of ACL prevention programs being recommended to female athletes. These programs involve doing agility, plyometrics, and strengthening exercises, all of which are performed in controlled situations. ACL tears, however, do not occur in controlled situations. I still perform more ACL reconstructions on men than women (70% versus 30%). If these prevention programs are effective, then they should prevent ACL tears in men as well. Any athlete, male or female, who has a small ACL is at higher risk for ACL injury than athletes with larger ACLs. It just so happens that more women than men have small ACLs.”

How has your ACL rehabilitation program evolved over the years?

“Since 1982, I have performed over 4000 ACL reconstructions. What is important to note is that I have used the same surgical technique since I began practice. This technique has always been reliable for obtaining predictable stability. Because I have not changed my method for surgery, I have been able to observe how changes in rehabilitation have affected the results. I have kept a database for ACL-reconstruction patients, which includes information regarding surgical factors, physical measurements, radiographic findings, and objective and subjective results. By keeping this database and by continually analyzing the results, I have been able to make observations regarding complications and rehabilitation problems through the years. With each problem encountered, we were able to analyze the many factors associated with the patient to determine what common variable might be responsible for the problem. Subsequently, we made changes in the rehabilitation program to improve our results.

“Initially, changes in rehabilitation have been made as an attempt to prevent the most common complication observed from ACL reconstruction surgery, knee stiffness. In the early 1980’s, the rate of arthrofibrosis was 19%. Since 1996, the percentage of patients who have required a scar resection for symptomatic loss of extension has been <1%.

“The major changes made in our approach to surgery and rehabilitation from 1982 through 1996 were as follows:

  • 1 No immobilization
    The initial change in rehabilitation was to incorporate the use of a CPM machine and progress to a removable 0° splint. Once I realized that patients were not using the splint, I stopped using it.
  • 2 Nonsurgical treatment of ACL/MCL injuries
    I found that patients with ACL/MCL injuries had a higher incidence of knee stiffness than patients with ACL injuries alone. Given that MCL injuries can heal without surgical treatment, we stopped performing surgery for the MCL. Instead, I began using cast immobilization for a short period to allow the MCL to heal. Then patients underwent rehabilitation to regain full range of motion and good leg control before undergoing ACL reconstruction.
  • 3 Noncompliant patients
    In 1986, I had an independent investigator interview my patients to determine how compliant patients were with the restrictions regarding weight bearing and doing sports activities. We found that patients were bearing weight soon after surgery and that some begin doing sporting activities around 2 months after surgery. When comparing the results of patients who were compliant and those who were noncompliant, we found there was no difference in stability between the groups, and patients who were noncompliant had better range of motion, more strength, and better confidence in their knees. These findings led to our development of the “accelerated rehabilitation” program that we began in 1987.
  • 4 Timing of Surgery
    Patients who underwent ACL surgery after an acute injury versus chronic instability had a higher rate of knee stiffness after surgery. An initial study found that patients who underwent surgery within 3 weeks of injury had a 12.5 % incidence of requiring a scar resection versus 4.2% for patients who underwent surgery at >3 weeks after injury. Subsequently, we determined that it was not necessarily the time from injury but the condition of the knee that was most important. Once a patient has no swelling, full hyperextension and flexion and good leg control, ACL reconstruction can be performed. In addition, the patient should be mentally prepared for surgery. The surgery is an elective procedure and should be performed at a time when it is convenient for the patient’s schedule with school and work.
  • 5 Locked bucket-handle meniscus tears
    Another group of patients who we found had a high incidence arthrofibrosis was that patients who had chronic ACL-deficiency and who sought treatment because they had a locked bucket-handle meniscus tear. When these patients underwent meniscus treatment and ACL reconstruction at the same time, they had a higher incidence of arthrofibrosis than those patients who underwent 2-staged procedures of meniscus treatment followed by an ACL reconstruction at an elective time once the knee regained full range of motion.
  • 6 Early postoperative rehabilitation
    The first 2 weeks after surgery are the most important with regard to rehabilitation. The key to success is to prevent a hemarthrosis. This is accomplished with the use of a Cryo/Cuff for compression and cold, CPM machine for elevation, and bed rest during the first 5 days after surgery. By preventing a hermarthrosis, the patient has an easier time of obtaining full range of motion and has less pain. Without a hemarthrosis, the patient does not have a problem with shut-down of the quadriceps muscle, so leg control exercises can be performed. During this time, patients can perform their range of motion exercises. Obtaining full hyperextension equal to the opposite normal knee is accomplished on the day of surgery and is monitored and maintained throughout the rehabilitation process. Flexion to about 100° should be accomplished by 1 week postoperative and flexion should be around 135° by 1 month. Aggressive leg strengthening exercises can begin once full range of motion has been achieved.
  • 7 Use of patellar tendon graft from the contralateral knee
    Because of my observation of the ease of rehabilitation for patients who underwent revision ACL reconstruction with a contralateral patellar tendon graft, I began using the contralateral graft source for primary ACL reconstruction in select patients 1994. Initially, I used the contralateral graft for patients who were involved in athletics and who desired to have a quick return to sports. However, because of the ease of regaining full range of motion, I began to use the contralateral graft source for other patients as well. I found that adult patients whose initial goal was to be able to comfortable return to work and daily activities, that using the contralateral graft allowed patients to attain these goals by 2 weeks after surgery. Because the patients were forced to use both legs equally, the return of strength and function was possible just by patients using both knees normally with every day activities. More advanced goals of returning to sporting activities could be achieved by specific donor site rehabilitation exercises to regain size and strength. Knee symmetry to the preoperative level has been the ultimate goal with surgery, and symmetry can be accomplished easier with using the contralateral graft.

“The peroperative rehabilitation program used for my patients has been one that has evolved and is still evolving. By continual data collection and analysis, I still strive to identify specific problem patients and we work to find solutions to those problems. I believe that a successful outcome in ACL reconstruction is based on the avoidance of any complications. Regardless of the graft site chosen, the ultimate goal with all patients should be to reconstruct the ACL-deficient knee with one surgery at the appropriate time and rehabilitate the knee so that it is symmetrical in motion, strength, and stability to the opposite knee.”