Principles of Anterior Cruciate Ligament Rehabilitation

Introduction

Rehabilitation with anterior cruciate ligament (ACL) reconstruction has evolved considerably since the 1970s, when intra-articular ACL reconstructions were first being performed. We have evolved from using casts on the leg for 6 weeks after surgery to no immobilization at all, from restricting weight bearing to encouraging weight bearing, from limiting range of motion to fostering stability to emphasizing exercises to achieve full knee extension and flexion, and from restricting the return to sports until 1 year after to surgery to allowing participation in sports as soon as the patient is able to do so. We made this progression by systematically evaluating how different factors about surgery and what patients actually did during rehabilitation affected our patients’ results, and then we made improvements in our rehabilitation techniques to improve the overall outcome.

Proper perioperative rehabilitation with ACL reconstruction is just as important as proper graft placement with surgery. We suggest that the orthopaedic surgeon needs to be intimately involved with the rehabilitation process to provide a consistent and effective program for patients to follow. The main complication after ACL reconstruction has been the limitation of knee range of motion or arthrofibrosis. It is believed that arthrofibrosis is more common with the patellar tendon autograft, but it is found with all graft sources. We believe that improper perioperative rehabilitation, not the graft source itself, is the culprit for causing arthrofibrosis and that it can be avoided with all ACL reconstruction surgery if the proper rehabilitation is applied before and after surgery.

Regardless of surgical technique or graft source, the goal for all patients after ACL reconstruction is to have a normal knee—one that has full range of motion, strength, and function. If the ACL-reconstructed knee feels different than the contralateral normal knee, then the patient can function only at the level of the worst leg. Therefore symmetry between legs is the ultimate goal, not just ACL stability.

People have symmetrical knees that are unique to the individual. In evaluating full range of motion, an important consideration is that 99% of women and 95% of men show some degree of hyperextension in their knees, with averages of 5 and 6 degrees, respectively. Current data analysis of results of ACL reconstruction shows that even a loss of 3–5 degrees of knee extension or 5 degrees of flexion are major factors related to lower subjective scores at 10–20 years after surgery. To measure knee extension, the heel of the foot should be placed on a bolster so that the knee can fall into hyperextension ( Fig. 109.1 ). The motion should be compared with the opposite normal knee. To get a kinesthetic feel for how easily the knee moves into hyperextension, the examiner can evaluate hyperextension by placing one hand above the knee to fix the femur and placing the other hand on the patient’s foot to lift the heel off the table. Knee flexion can be measured by having the patient pull the heels toward the buttocks. When the knee is normal, the patient can kneel and sit back on the heels comfortably. These evaluation tools should be used to determine whether the patient has full symmetrical knee motion.

With the knowledge that full range of motion is essential, we have designed our perioperative rehabilitation program with the principal goal of achieving postoperative symmetry between knees. The program begins at the time of the initial evaluation to include preoperative rehabilitation through the time the patient is fully recovered and has returned to full activities. Patients follow a cascade of events that has few time constraints but must be followed sequentially to be most effective.

Preoperative Rehabilitation

After an acute ACL injury, the knee almost always develops a hemarthrosis, which causes the knee to lose range of motion and the leg to lose some quadriceps muscle strength. Patients typically walk with a bent-knee gait and require crutch assistance. The patient should regain normal knee range of motion with very little swelling, and should be able to walk with a normal gait, as this reduces the likelihood of motion problems postoperatively.

A habit of performing full hyperextension exercises is important to develop preoperatively so that the exercises are easily a part of a daily routine after surgery. Exercises are used to gain full normal hyperextension, including towel stretches, active heel lift, heel props on a bolster high enough to elevate both the calf and the thigh, and standing on the affected leg with the knee in full hyperextension. Regaining full knee flexion is achieved through performing wall slide and heel slide exercises. Full weight bearing is allowed as tolerated by the patient, but a normal gait pattern must be achieved. Crutches are used to assist ambulation if the patient exhibits an antalgic gait pattern. Once a normal gait pattern is obtained, patients are allowed to ambulate without the use of any assistive device or prophylactic braces. Once the patient has achieved full range of motion, good leg control, and a normal gait with minimal swelling, he or she can begin a low-impact strength and conditioning program until surgery.

The overall goal of physical therapy in the preoperative phase is to control and decrease pain and swelling, restore full range of motion, restore a normal gait pattern, and initiate a strengthening program. By accomplishing these goals, the patient will have a normal-appearing and functioning knee, except for the absence of the ACL.

Another important factor in the preoperative preparation of an ACL reconstruction procedure is the mental preparation of the patient. Physical therapists follow patients closely and communicate with the surgeon regarding a patient’s mental and physical preparation for surgery, as the success of reconstruction depends on both factors. The patient should approach the reconstruction procedure with a positive mental outlook. A “let’s just get it over with” attitude is not acceptable and can lead to less than superior results, even with perfect surgical and rehabilitation techniques. The patient should arrive in the operating room ready to go with an attitude of looking forward to the reconstructive procedure and with an understanding of the postoperative rehabilitation.

Postoperative Rehabilitation