Chapter 65 Principles of Anterior Cruciate Ligament Rehabilitation
Introduction
The main complication after ACL reconstruction has been the limitation of knee range of motion or arthrofibrosis. Arthrofibrosis is defined as abnormal proliferation of fibrous tissue in and around a joint that can lead to loss of motion, pain, and muscle weakness. It is believed that arthrofibrosis is more common with the patellar tendon autograft, but it is found with all graft sources.1–4 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.
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.5 Current data analysis of results of ACL reconstruction shows that any loss of knee extension or flexion is the major factor related to lower subjective scores at 10 to 20 years after surgery. Even the loss of 3 to 5 degrees of extension compared with the opposite knee can result in lower postoperative subjective scores.6 Thus the definition of full range of motion must depend on symmetry between the knees rather than the conventional practice of gauging knee motion against a fixed standard.
To measure knee extension, the heel of the foot should be placed on a bolster so that the knee can fall into hyperextension (Fig. 65-1). The motion should be compared with the opposite normal knee. To get a kinetic 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 (Fig. 65-2). 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 (Fig. 65-3). These evaluation tools should be used to determine whether the patient has full symmetrical knee motion.
Preoperative Rehabilitation
The initial emphasis after an acute injury to the ACL is to control and then decrease the amount of swelling and pain. We use the knee Cryo/Cuff (Aircast, Summit, NJ), which combines cold with compression to reduce the hemarthrosis. The second goal of rehabilitation after an acute ACL injury is to restore normal knee range of motion, including full hyperextension equal to the noninjured knee. Obtaining full range of motion before surgery reduces the likelihood of motion problems postoperatively.7–9
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. Several exercises and modalities are used to gain full normal hyperextension. Towel stretches are performed as a passive self-mobilization technique using a towel looped around the midfoot. The towel ends are held in one hand while the other hand is used to press and hold the thigh to the table. The towel is used to lift the heel of the affected lower extremity to end-range hyperextension by pulling the end of the towel upward toward the shoulder, where it is held for a count of 5 seconds, and then the heel is lowered back to the table (Fig. 65-4). For patients who have decreased quadriceps muscle control, an active heel-lift exercise can easily be added to the towel stretch. The active heel lift is accomplished by contracting the quadriceps musculature after the towel stretch is performed, trying to keep the heel of the affected leg elevated without using the towel to hold it in the air. Initially after injury, patients often display some degree of quadriceps muscle inhibition, making a normal gait pattern difficult. It is important that the patient continue to try to actively elevate the heel to the height of the passive stretch.
Mental Preparation
The second 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.10 The physician must explain the nature of the injury to the athlete and family. The patient benefits from a detailed explanation of the operative procedure and the postoperative rehabilitation. The physical therapist should also review with the patient exactly what will be performed in all phases of the postoperative rehabilitation and how each phase of rehabilitation will be accomplished. 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
Ipsilateral or Contralateral Graft
Rehabilitation after ACL reconstruction involves two different rehabilitation efforts with different goals. First is the rehabilitation of the knee as it pertains to the placement of the ACL graft intraarticularly. Second is the rehabilitation of the graft donor site. To do both effectively in the same knee, one rehabilitation effort must take precedence over the other to prevent the main complication of arthrofibrosis in the knee. Of utmost importance for the ACL graft in the short and long term is achieving full knee range of motion equal to the normal knee. This includes full hyperextension and the patient’s ability to kneel and sit back on his or her heels, as shown in Figs. 65-1 to 65-3. To rehabilitate the graft donor site, repetitive stress must be applied to the patellar tendon to stimulate it to regrow in size and strength. The sooner this repetitive stress can be provided, the more one can take advantage of the inflammatory response from harvesting the middle third of the patellar tendon. These two immediate goals for the ACL graft and the graft donor site are difficult to achieve simultaneously in the same knee without causing swelling and difficulty with achieving full range of motion. Therefore when a graft is harvested from the ipsilateral knee, the goal of achieving full range of motion takes precedence over rehabilitating the graft donor site.
Our choice of whether to use an ipsilateral or a contralateral patellar tendon graft is based solely on the individual patient goals. The senior author used ipsilateral grafts for primary ACL surgery from 1982 to 1994 but used contralateral grafts during that time period for revision ACL reconstruction when patients had already had the patellar tendon graft used in their involved knees for primary reconstruction. We observed the ease of rehabilitation experienced by patients when the contralateral patellar tendon was used for revision surgery, especially with regard to the quick return of knee range of motion in the ACL reconstructed knee.10–12 Patients also reported that the ACL reconstructed knee felt normal to them very early after surgery, and they were able to return to their normal activities and sports very quickly. We initially began using the contralateral graft for primary ACL reconstruction in high-level athletes who wanted a quick return to sport. With its success and ease for achieving full symmetrical range of motion and strength, we realized that the use of the contralateral graft was appropriate for any patient.13 We currently use the contralateral graft source for about 75% of patients.