What I have learned about the ACL: utilizing a progressive rehabilitation scheme to achieve total knee symmetry after anterior cruciate ligament reconstruction

It is essential that rehabilitation of an ACL injury begin immediately after the initial office evaluation. Prior to any operative intervention, patients are referred to our physical therapist for preoperative evaluation and readiness. Details of the patient’s present athletic activities and any future aspirations are important when planning postoperative rehabilitation. Physical therapists follow patients closely and communicate with the surgeon regarding the patient’s mental and physical preparation for surgery, as the success of reconstruction depends on both factors.3,12

Patients who desire ACL reconstruction are counseled about preoperative rehabilitation and their active role in the process. Before surgery is considered, patients are expected to meet a series of conditions, including completely normal ROM equal to that of the opposite knee, reduced knee effusion, normal gait, and good leg control. To achieve those ends, a series of exercises is utilized along with a Cryo/Cuff to reduce swelling. The exercises include towel stretches (Fig. 5), heel props exercises, standing extension habit, wall slide and heel slide exercises, and gait training. We perform preoperative testing so we can have objective measures for closely monitoring postoperative progress. Preoperative KT-1000 arthrometer measurements document knee laxity, and isokinetic testing objectively measures quadriceps muscle strength. Obtaining full ROM before surgery reduces the likelihood of motion problems postoperatively, so surgery is not performed until a patient has full extension equal to that of the noninvolved knee and is able to sit on his or her heels (Fig. 6). Other benefits of preoperative rehabilitation include familiarizing the patient with the same exercises he or she will be performing postoperatively and establishing a meaningful relationship between physical therapist and patient.

Postoperative rehabilitation begins in the operating room after graft placement to ensure full ROM and to prevent overtension. An antiembolism stocking is placed on the ACL-reconstructed leg along with a Cryo/Cuff (Fig. 7). The ACL-reconstructed knee is then placed in a continuous passive movement (CPM) machine to elevate the lower leg above the heart, as the key to early wound healing is eliminating knee effusion and hemarthrosis.1 The CPM machine is utilized for slow, assisted flexion to 125°. Heel slide exercises are performed with a yardstick positioned next to the leg with the zero end lined up with the end of the heel. The patient flexes the knee with the help of a towel looped under the thigh, and terminal flexion is held for 1min. The number of centimeters the heel has traveled is recorded by referencing the yardstick. The initial flexion should fall approximately in the range of 110°–120°, and the patient should use the yardstick method to gauge progress during the subsequent days. Hyperextension exercises include heel prop and towel stretch exercises. Heel prop exercises involve propping the heel on a rolled towel and then placing a 2.5-pound weight just distal to the incision for a 10-min period. Following heel raises, a patient performs three to five knee “thunks,” in which he or she flexes the knee to a height of several inches and then relaxes it, allowing it to fall into hyperextension. To complete the extension exercises, five to ten towel stretches are performed in combination with active heel raises to demonstrate quadriceps control. The patient stays in the hospital overnight to allow patient and family education about the goals that should be achieved during the first week at home. He is released the next day so long as he can demonstrate full extension, at least 110° of flexion, and is able to lift the ACL-reconstructed leg independently with quadriceps muscle contraction.

Once at home, patients are instructed to minimize swelling by limiting out-of-bed activities for the first 5 days after surgery and using the Cryo/Cuff and CPM at all times when not performing exercises. The previously mentioned exercise sets are all performed six times per day, with measurements recorded in a home exercise log. Patients receive a phone call from the physical therapist daily so they can ask any questions they have about their rehabilitation. Throughout the first phase of rehabilitation, knee extension is emphasized more than flexion. If extension becomes an issue, the Elite Seat, a portable, reclining extension device controlled by a hand lever, can be utilized (Fig. 8). The first postoperative visit is conducted about 1 week after surgery. At that time, progress is assessed; and if satisfactory goals have been achieved, the patient progresses to the next phase of rehabilitation. Aggressive strengthening exercises are introduced once the patient achieves full knee flexion. Regeneration of the graft site is achieved by high repetitions of step-up exercises on a step box. When full terminal extension and knee flexion are present, strengthening with the use of a stair machine and leg press exercises is initiated. For the first 4 weeks, the tendon is induced to regrow and hypertrophy. For the subsequent 4 weeks, the tendon is made stronger; after this point, specific functional exercises are conducted. Early return to sports-specific drills such as shooting baskets and kicking a ball can be started. Prior to increasing activity level, patients should have full hyperextension and be able to sit on their heels comfortably. When the return of strength is 70% of the preoperative normal leg value, functional progression of sports agility can be initiated. If swelling occurs in the ACL-reconstructed knee or the ROM decreases at any time, activity should be curtailed until full motion has been reestablished. The full range of expected goals and corresponding exercises from time of surgery until 8 weeks postoperatively are detailed in Table 2. At this point, the patient has ideally progressed to sport-specific drills and is making the jump from part-time to full-time competition.1,9

Following surgery, patients participate in subjective and objective postoperative evaluations in which patients are sent modified Noyes and IKDC subjective questionnaires on a yearly basis. They are also asked to return for objective evaluation 1, 2, 5, 10, 15 and 20 years after surgery.