The anterior cruciate ligament (ACL) is an important stabilizing and biomechanical function for the knee. Reconstruction of the ACL is one of the most commonly performed procedures in the field of sports medicine. It is estimated that 200,000 ACL tears occur each year with 100,000 ACL reconstructive surgeries done each year in the United States (22). Restoration of normal knee function and protection from further intra-articular injury are the goals of treatment and have led to research for the development of new operative techniques. Preparation for ACL surgery should include consultation with the patient regarding functional expectations and postoperative activity. Reconstruction of the ACL with the bone-patella tendon-bone (BPTB) autograft secured with an interference screw has been described as a successful method of ACL reconstruction, in particular with young men with no antecedent knee pain.

Reconstruction of the ACL with BPTB autograft secured with interference screws was first described by Jones in 1963 and later popularized by Clancy in 1982 (5,13). The BPTB autograft reconstruction accomplishes some of the fundamental goals of ACL reconstruction: ease of graft harvest, minimal harvest-site morbidity, and biomechanical properties that are similar to those of the native ligament. It also possesses high initial strength and stiffness and can be secured predictably with rapid incorporation into host tissue that allows for early, aggressive rehabilitation while recreating the anatomy and function of the native knee (4,10,23). Arthroscopically assisted BPTB autograft also has the advantage of a single incision, leading to shorter operating times, reduced postoperative morbidity, improved cosmesis, and quicker rehabilitation. The disadvantages of bone patellar-tendon bone ACL reconstruction include graft site morbidity, disruption of the extensor mechanism, patella fracture, patella baja, and patellofemoral pain (6,14,15). It is important for the orthopaedic surgeon to be aware of the advantages and disadvantages of using BPTB autograft and compare those to factors related to other graft choices and apply pertinent information to each individual patient who is a candidate for reconstruction. Regardless of graft choice, a clear understanding of the critical stages of arthroscopic ACL reconstruction and knowledge of the potential pitfalls can help avoid complications and produce consistently excellent results. This chapter seeks to provide a reproducible technique for endoscopic ACL reconstruction using BPTB autograft.

ACL injuries can occur in numerous ways, but there are a few mechanisms that predominate. Although up to one third of the time the patient is unable to give clarity to the mechanism of injury, when an account is given patients with ACL injuries often report a noncontact pivoting injury with a deceleration and rotational component during running, cutting, or jumping (11,27). The injury is often associated with an audible “pop” heard by the patient at the time of injury. The patient usually falls to the ground and is not able to resume activity. An effusion usually ensues within a few hours in comparison to a meniscus tear where swelling usually occurs within 24 hours (22,37). In contrast to noncontact injuries, contact injuries can also lead to ACL disruption and usually involve a hyperextension and/or valgus force to the knee by a direct blow.

The physical examination and preoperative assessment of the knee joint is critical to successful outcomes from ACL surgery. With an adequate history and physical examination, an ACL injury can often be diagnosed
proficiently without additional studies. Most sports medicine physicians agree that the examination is most accurately performed immediately after the injury, before swelling, pain, and muscle spasms occur. Collateral ligament and meniscal injuries can be identified through the history and physical examination; therefore, a complete examination of the knee should be performed in order for improved interpretation of diagnostic studies, for optimal surgical tool acquisition in preparation for the operating room, and for optimal physician-patient communication about expected outcomes. Poor outcomes are associated with poor range of motion, weak quadriceps function, and excessive swelling. Therefore, it is plausible to delay surgery until full extension is achieved, optimal skin and soft tissue factors have resolved (minimal swelling), and quadriceps function is in the activated state (34).

The physical exam should begin with examination of the uninjured knee. This helps to familiarize the patient with the knee examination and helps the examiner determine patient-specific normal parameters. Examination of the injured knee begins with visual inspection for evidence of swelling and lacerations. After inspection, palpation ensues with confirmation of any suspected effusions and to what degree they are present. Next quantitative measures of the patient’s active and passive range of motion are obtained and recorded. After taking the patient through a range of motion, the patient’s knee can be brought to 90 degrees and inspection of meniscal pathology may proceed with palpation of the medial and lateral joint line. While at 90 degrees of flexion, the anterior drawer test is performed to evaluate anterior tibial translation. This is performed by stabilizing the foot of the affected knee while placing an anterior force on the tibia. Next the patient is brought out into 20 to 30 degrees of flexion and the Lachman test is performed (Fig. 26.1). This test has become the hallmark of anterior laxity testing in the knee and involves stabilization of the femur with one hand while an anterior force is applied to the tibia with the other hand (41). The degree of translation of the tibia as well as the characterization of the endpoint is recorded. The laxity is based on comparison of the contralateral knee and not as the degree of absolute translation. Grade 1 laxity is 1 to 5 mm of translation. Grade 2 laxity is 6 to 10 mm of translation. Grade 3 laxity is more than 10 mm of translation. Varus and valgus stressing can also be applied to the knee at 20 to 30 degrees to assess lateral collateral ligament and the medical collateral ligament (MCL) competency, respectively. The knee can then be brought out into extension with varus and valgus stressing applied once again to determine if there are other associated injuries (37). The pivot shift test is a special maneuver to assess the rotational component of ACL competency, requires an intact MCL, and begins with the patient in extension (22). The examiner places a valgus directed force, axial load, and internal rotation on the extended knee and proceeds to slowly flex the knee. At approximately 30 degrees of flexion, a reduction of the subluxation can be felt or heard. The test is based on the lateral tibial plateau subluxing anteriorly with extension and reducing with flexion and is pathognomonic of ACL deficiency (8,9) (Fig. 26.2). This maneuver is often poorly tolerated by awake patients and should be performed toward the end of the physical examination secondary to subsequent patient apprehension and guarding. The pivot shift test is often best tested under anesthesia.

Plain radiographs of the knee should be obtained during the initial evaluation to rule out fractures about the femorotibial joint. The Segond fracture is an avulsion of the anterolateral capsule of the tibia and is thought to be a pathognomonic radiographic finding of ACL injury (43). If the patient is immature skeletally or skeletally mature with osteopenia, an avulsion of the tibial insertion of the ACL, which results in a nonfunctioning ACL, can also be seen on plain radiographs. Plain radiographs also reveal osteochondral lesions, loose bodies, degenerative joint disease, and overall alignment of the knee. Specific to planning for BPTB autograft reconstruction, appropriate preoperative radiographic assessment of the patellar tendon with a true lateral radiograph is important to ensure adequate graft length (10,18). Radiographs also help to note the presence of any ossicles within the tendon. These ossicles can be associated with Sinding-Larsen-Johansson (proximal ossicles) or Osgood Schlatter syndrome(distal ossicles) and can compromise graft competency or length if improperly addressed (19).

Following radiographs, an MRI is the most useful diagnostic study for detecting ACL tears with a reported accuracy of 70% to 100% (22,26). The normal ACL is seen as a defined band through the intercondylar notch. With disruption, the ligament is ill-defined, with a mixed signal intensity representing local edema and hemorrhage (42). MRI can also reveal any associated meniscal tears, chondral injuries, or bone bruises. The typical bone bruise pattern is increased signal intensity on T2-weighted images on the lateral tibial plateau and lateral femoral condyle and these are present in up to 80% of patients with ACL injuries (12,31,38). Patients who cannot undergo MRI imaging may be candidates of stress radiographs; however, these are primarily used to diagnose posterior cruciate ligament (PCL) injuries.

Reconstruction of the ACL can be performed under regional (spinal or epidural) or general anesthesia supplemented by a femoral and/or sciatic nerve block to assist with postoperative analgesia (10,25). Once the appropriate anesthesia has been chosen and induced, preoperative antibiotics should be given to the patient should be given to the patient. An examination under anesthesia can then be performed. The previously mentioned tests specific for ACL function are performed including the Lachman, anterior drawer, and pivot shift examinations. One can also determine PCL function with a posterior drawer test and collateral ligament function with the knee in extension and 30 degrees of flexion. The surgeon should test the extent of combined injuries by assessing external rotation stability in 30 and 90 degrees of flexion indicating a posterolateral corner (PLC) or combined PCL/PLC injury, respectively.

After performing the examination under anesthesia, a nonsterile tourniquet is placed on the operative extremity high on the thigh. A reliable technique for placement of the tourniquet is to bend the knee of the operative leg and place the foot on the edge of the bed with the hip in about 40 to 45 degrees of abduction. The person applying the tourniquet uses their chest against the anterior portion of the patient’s knee for stabilization. Padding is applied to the upper thigh and the tourniquet is applied as far proximal as possible. After application, the skin just distal to the tourniquet is tugged slightly to prevent slippage. The contralateral leg is placed in the lithotomy position in a commercially available well-leg holder with care taken to prevent injury to the hip and padding for protection of the peroneal nerve. The foot of the bed is then lowered allowing the operative extremity to hang free with the knee in 90 degrees of flexion and allowing flexion to 120 degrees during the procedure (Fig. 26.3).

The operative leg is then prepped and draped using standard sterile technique. Once draped, markings are made on the patient’s skin for the tibial tubercle, the borders of the patella, and portal sites. A marking is then made for the proposed incision for graft harvest (Fig. 26.4). The operative leg is exsanguinated with a commercially available Esmarch bandage. The tourniquet is inflated to 275 to 300 mm Hg and the procedure begins.