Radiographs

Radiographs are obtained preoperatively to assist with surgery planning.

Plain radiographs, including standing posteroanterior 45 degrees flexed weight bearing,² lateral, and Merchant³ views are obtained. The radiographs allow us to measure the width of the intercondylar notch, length of the patellar tendon, tibial slope angle, and width of the patella, which is usually twice the width of the patellar tendon. These measurements are helpful for planning the angle and length of the femoral tunnel and help determine the amount of notchplasty that may be needed to accommodate for the width of the new ACL graft. A magnetic resonance imaging (MRI) scan is not necessary for our preoperative evaluation but is reviewed if it has already been obtained elsewhere.

Rehabilitation

There is never a reason to do an isolated ACL reconstruction as an emergency surgery. Previous studies have shown that acute ACL reconstruction has a higher rate of postoperative arthrofibrosis than delayed ACL reconstruction when the patient has the opportunity to undergo rehabilitation to allow the knee to return to a quiescent state.^4,5 All patients are evaluated by a physical therapist at the time of my initial evaluation. The physical therapist measures knee range of motion and strength before surgery and determines when the patient is ready to undergo surgery. The patient must have full knee range of motion equal to the contralateral normal knee, good leg control, and no knee swelling before he or she can undergo surgery. Furthermore, the patient must be mentally prepared for surgery. The surgery and rehabilitation program are fully explained to the patient and his or her caregiver so that they fully understand what is expected of them after surgery. The surgery date is planned for a time when the patient has at least 1 week off school or work and when a family member or friend can be at home with him or her during the first week postoperatively.

Preparation

The patient lies supine on the operating table and is given a general endotracheal anesthesia. A knee evaluation for stability, range of motion, and effusion is performed after the patient is under anesthesia. The patient’s knees are positioned over the break in the table for flexion later. A tourniquet is applied to the thigh.

A 30-mg bolus of ketorolac is administered for preemptive pain management. Then 90 mg of ketorolac is mixed with 1000 mL of saline and an intravenous drip is started to run at 40 m/hr until completion of the dose. Intravenous antibiotics are infused.

The knee is preinjected with 0.25% Marcaine (bupivacaine hydrochloride, Winthrop, New York, NY) with epinephrine. The operative site is prepped with alcohol, and then the entire leg is painted with povidone-iodine (Betadine). An impervious stockinette is applied.

Arthroscopic Evaluation

An arthroscopy is performed to examine the knee joint for articular cartilage damage and meniscal tears. Meniscal tears are treated with either repair or removal or are left in situ as appropriate. After the arthroscopy, the leg is redraped and Ioban (3M Healthcare, St. Paul, MN) is placed on the knee over the openings cut in the stockinette. A bump is placed under the distal thigh to hold the leg in 25 degrees of flexion.

Exposure

The tourniquet is left inflated to 300 mHg/psi (350 mHg/psi for larger thighs). The Ioban drape is taken off the skin just over the site where the skin incision is to be made. A 6-cm incision is made down to the deep fascia along the medial side of the patellar tendon, starting 1 cm above the inferior pole of the patella and extending 4 cm distal to the joint line (Fig. 49-1). The subcutaneous tissue is separated from the deep fascia medially where the tibial tunnel is to be drilled 4 cm distal to the joint and 1 cm medial to the tibia tubercle. The subcutaneous tissue is separated from the deep fascia with Metzenbaum scissors and finger dissection approximately 1 to 2 cm medial to the patellar tendon.

Fig. 49-1 A 6-cm incision is made along the medial side of the patellar tendon starting 1 cm above the inferior pole of the patella and extending 4 cm distal to the joint line.

Tibial Exposure

The deep fascia and periosteum of the proximal tibia are incised with electrocautery starting from the joint line and extending distally along the medial edge of the patellar tendon for 4 cm, then cutting at a right angle for another 2 cm to outline a flap to the level just proximal to the pes anserinus. The periosteum/fascial flap is lifted with a periosteal elevator to expose bare bone where the tibial tunnel will be created, made, and drilled (Fig. 49-2). Exposure at this level will ensure the tibial tunnel will be at least 40 mm long for the 25-mm bone plugs. The flap is kept as thick and continuous as possible to allow for closure of the soft tissue over the polyethylene button used for fixation, which has reduced the need for postoperative hardware removal.

Fig. 49-2 A periosteum/fascial flap is lifted to expose the bone at the site where the tibial tunnel is drilled.

Medial Arthrotomy

A finger is used to put tension on the medial capsule just medial to the patella as electrocautery is used to incise the capsule into the joint at 5 to 10 mm medial to the patella, starting at the level of the lower third of the patella, extending distally to the tibia, and staying medial to the fat pad. Tension is applied to the synovial layer with forceps on both sides of the incision. After making an opening in the synovium, a Z retractor is inserted to retract the patellar tendon laterally. A small fork retractor is inserted inside the synovium to retract the soft tissue medially. The incision is extended distally along the medial edge of the patellar tendon toward the tibial periosteal incision, thus connecting the two incisions. The incision in the fat pad should stay just medial to the ligamentum mucosum for better exposure of the joint. At the tibial plateau, the soft tissue is incised up to the intermeniscal ligament. Proximally, an incision is made in the retinaculum up to the distal fibers of the vastus medialis obliquus, cutting from inside the joint toward the surface to avoid inadvertent injury to the articular surface. It is not necessary to dislocate the patella for this exposure.

Femoral Exposure

The patellar tendon length is determined preoperatively from a 60-degree-flexion lateral plain radiograph. The length of the tendon varies from 34 to 74 mm (mean 49 mm for men and 46 mm for women). Longer patellar tendons need longer femoral tunnels. The intraarticular ACL length varies from 22 to 30 mm, so the extra length of the graft is placed in the femur. The bone plug in the tibia is placed just distal to the medial tibial spine because the only hard cancellous bone in the tibia is at the proximal joint line. The femoral tunnel exit site is adjusted based on the length of the graft. For longer patellar tendons, the incision will be made more proximally; for shorter patellar tendons, the incision is made more distally. In our experience, an oblique incision has resulted in fewer wound-healing problems than a longitudinal incision in line with the iliotibial band.

The table is elevated so that the femur is close to eye level. The foot of the bed is lowered so that the knee is flexed to 90 degrees. The bump under the thigh may need to be adjusted to allow for 90 degrees of flexion. The goal is to expose the flat surface of the lateral femoral cortex above the metaphyseal flare. The 3-cm lateral oblique incision is made about 4 to 5 cm above the superior pole of the patella along Langer’s lines (Fig. 49-3