The patient with a torn ACL typically presents with one of two scenarios. A noncontact injury sustained during pivoting or cutting activities, or from traumatic contact. Establishing the mechanism of injury remains important as it may suggest other pathologies, particularly with varus or valgus loads with subsequent injury to the MCL, LCL, PL corner, and menisci. Failure to recognize additional structural injuries will result in higher failure rates regardless of the reconstructive method (6). Oftentimes, a “pop” is described and an effusion present. Some patients
will attempt to return to activities before seeking treatment and may complain of persistent instability. For those that deny instability but have an isolated ACL tear, this may be a significant factor in the decision-making process and avoid surgery.

Age is also an important consideration. Within the preadolescent and teenager population, it is critical to evaluate growth plates, and those with advanced age have increased risk of degenerative joint disease that may preclude surgical intervention.

Lifestyle should also be evaluated as a sedentary individual may not have the same functional demands as an elite athlete. Prior surgical procedures or infections of the affected extremity must be considered as there are associated surgical risks.

Most patients are evaluated in the office setting, however, evaluation at the time of injury can provide valuable information as there is little/no swelling present. The patient is asked to wear shorts to allow for direct visualization of both lower extremities and comparison throughout the examination. The affected knee is first inspected noting any joint effusion, bruising, or atrophy. The overall alignment is also observed as significant angular deformities may need to be addressed. The range of motion is measured and followed as this needs to be optimized prior to any surgical intervention. Palpation of all bony prominences as well as the joint line and parapatellar region helps identify associated meniscal, ligamentous, and patellofemoral injuries. Tests specific for the ACL ruptures are performed including the Lachman, anterior drawer, and pivot shift maneuvers. Although more sensitive, the pivot shift may be difficult as patients tend to guard especially in the acute setting. Supplementing the examination, the McMurray, varus and valgus stress at 0° and 30°, Dial, reverse pivot shift, and posterior drawer testing are performed for completion.

Objective methods are also employed as part of the evaluation and include the KT-2000 arthrometer. Dysfunction or disruption of the ACL is suggested with sideto side differences greater than 3 mm.

Radiographs remain a key component during the workup of ACL-injured patient and help to identify tibial spine avulsions or rule out associated fractures, evaluate limb malalignment, and assess with open growth plates. Standard radiographs include the weightbearing full extension and 45° posteroanterior X-rays, nonweightbearing lateral, and merchant views. For patients where the physical examination suggests lower extremity malalignment, a bilateral long cassette view is obtained for further assessment. The need for an MRI is arguable, but patients often present having already had the study and within our practice an MRI is obtained for further identification associated injuries.

CT scans are not necessary for primary ACL reconstruction, but have a preoperative role in revision cases.

Persistent instability that causes functional limitations with either activities of daily living or with sports remain critical aspects when deciding whether or not to pursue surgical intervention.

Prior to surgery, the surgeon identifies, initials, and marks the operative site with a “yes.” A discussion is held between the surgeon, anesthesiologist, and the patient to develop an appropriate anesthesia regimen. Typically, peripheral nerve blocks involving the femoral and sciatic nerves are performed by an experienced anesthesiologist utilizing ultrasound guidance. In combination with “light” sedation, these temporary nerve blocks provide adequate intraoperative pain control and helps minimize postoperative narcotic use.

The patient is brought back to the operating suite and placed supine on the OR table. After adequate anesthesia and analgesia, an examination under anesthesia is performed. Specific tests include the Lachman, pivot shift, anterior drawer, posterior drawer, varus/valgus stress, Dial testing, and range of motion. The foot of the table is maximally flexed, allowing for. The nonoperative limb is comfortably place in a well-padded leg holder with the hip and knee flexed to 80° to 90° and positioned in abduction. A tourniquet is placed proximally on the operative thigh and secured with a bolster. All neurovascular and bony prominences are cushioned and protected. Securing the leg in slight hip flexion (10° to 20°) allows for increased knee flexion for later femoral tunnel creation. The operative knee should have a range of motion from 0° to at least 120° (Fig. 71.2).

Critical to the success and limited invasiveness of arthroscopic ACL reconstruction are appropriately placed skin incisions. With properly placed portals, a notchplasty is not required and all tunnels may be created with careful portal placement. The anatomic landmarks are identified and marked, including the inferior pole of the patella, medial, and lateral borders of the patellar tendon, medial joint line, tibial tubercle, and anterior and posteromedial borders of the tibia. Additional incisions may be required for meniscal repair depending on the chosen technique. The leg is elevated and an esmarch is used to exsanguinate the leg for tourniquet insufflation.

With the knee in 90° of flexion, the anterolateral portal (LP) is established just lateral to the origin of the patellar tendon on the inferior pole of the patella. A no. 11 blade scalpel is used to make the vertical incision. The arthroscopic trocar is then used to enter the joint and sweep under the medially lying fatpad. This portal is used primarily for visualization of the tibial ACL footprint.

Again with the knee in 90° of flexion, the central medial portal (CMP) is established. A no. 18G spinal needle is used to determine the trajectory of the instrumentation and visualization pathway from the CMP. The needle typically follows the course of the normal ACL. The skin incision should be tangential to the medial border of the patellar tendon and just superior to the anterior horn of the medial meniscus. This position allows for optimal visualization of the notch and femoral footprint. It also allows for adequate working space for the third arthroscopic portal—the Accessory medial portal (AMP). A no. 11 blade scalpel is used to make a vertical incision in the skin, carefully cutting away from the underlying medial meniscus. Prior to placement of the AMP portal, it is often necessary to debride the fatpad and improve arthroscopic visualization to optimize the portal placement (Fig. 71.3). The accessory medial portal is perhaps the most critical of all the portals as the trajectory must capture the AM and PL ACL origins of the femur while avoiding damage to the cartilage surface of the medial femoral condyle. If the portal is placed too medial, then the femoral AM tunnel entrance angle may be too acute and risk posterior wall blowout of the lateral femoral condyle.