The “Isolated” Anterior Cruciate Ligament-Injured Knee

An 18-year-old secondary school athlete who has lettered in three sports sustained a noncontact injury to his right knee as he cut to the left in the second football game of his senior year. He heard a “pop” and was unable to continue play. The team physician, an orthopaedic surgeon, examined the knee on the field and felt it was “loose.” Re-examination the following day in the office confirmed the on-field impressions. The following diagnostic clues and findings were recorded.

The history was straightforward and suggested a tear of the ACL. The patient was a dedicated, disciplined athlete, and was determined to continue recreational sports. Physical examination with a positive Lachman test and a positive pivot shift test is indicative of a tear of the ACL. Is manual examination enough? In today’s world, I prefer magnetic resonance imaging (MRI) for a more complete three-dimensional anatomic diagnosis. Although we must learn to read our own images, the presence of a radiographer schooled in joint-specific pathology is invaluable. The attending physician should settle for no less than quality imaging read by a radiographer of experience with complete diagnostic detail.

An MRI was obtained and showed a complete tear of the anterior cruciate ligament in its proximal third, a bone bruise of the lateral condyle and posterior tibia, and intact menisci. There were no obvious chondral lesions (Fig. 3.1.1).

The MRI was convincing. The patient and family wanted the knee repaired as soon as possible. They understood the implications of repair and rehabilitation.

Timing of the surgery is the next critical detail. The work of Shelbourne and Foulk⁶ and others in their group has brought great attention to this variable. I concur that it is usually in the best interest of the patient to perform the surgery on an elective basis after the effusion has resolved and motion has returned. The patient described in the history attended therapy diligently and was ready for surgery 2 weeks after the injury, with the effusion resolved and a near full range of motion. The examination before surgery confirmed a 6-mm injured-minus-noninjured knee Lachman result and a positive pivot test.

What makes the practice of medicine unique is the infinite variability of “the plan.” We formulate the treatment plan by the subtle integration of all relevant factors—some obvious, some learned through experience, and some intuitive. The “best” treatment plan is the plan in which both the patient and surgeon have confidence. Perfecting this art of selecting the best treatment plan for each patient is an unending quest. The challenge is what keeps physicians vital through years of practice. Experience is important in formulating a treatment plan. Sometimes the surgeon is uncertain. Sometimes the patient is uncertain. Usually, I propose a tentative plan to the patient and then back off to allow response to the initial implications. I always let patients know that their input and insight are essential in formulating a plan for their care.

I have often found that my time is equally divided between the physical examination and formulating the plan with the patient. Ultimately, however, the physician is responsible for the contract made with the patient. If the patient finds it difficult to establish a firm contractural relationship, he or she should seek a second opinion. The surgeon should be quick to suggest further consultation when it is obvious the decision-making is difficult.

For this patient, a young dedicated athlete, the plan seemed relatively straight-forward—reconstruction of the ACL at the appropriate time with an extensive and thorough rehabilitation program to follow. Most patients wish to know which graft the surgeon is going to use. This level of sophistication is not uncommon and deserves respect. I explained to the patient that there are four choices: bone-patellar tendon-bone, hamstring grafts, allografts, and primary repair. I will usually end this brief discussion by expressing my preference for one of the four choices. This preference is not always the same. I frequently modify the choice of graft depending on the functional demands of the patient and certain anatomic features relevant to that patient. I also like to keep a window open for primary repair or “the healing response” (see Chapter 10), as I believe that sometimes this is the appropriate solution. I further explain that the final decision cannot be made until the time of surgery. Thus, I try to retain control of graft selection rather than allow the patient to pre-empt my experience on this matter.

There are cases in which the patients decline surgery. This is their right. At this juncture, I usually encourage them to seek another opinion. Sometimes it is necessary to treat a patient nonoperatively for either medical reasons or as the result of the patient’s choice. For such a patient, I would consider immobilizing the knee in 20 degrees of flexion for 3 to 5 weeks. This course at least would have allowed the secondary restraints to begin healing and might have allowed the ACL to fall on the posterior cruciate ligament, and gain a secondary source of attachment and blood supply (Fig. 3.1.2). This mechanism was described by Wittek.⁷ This “repair,” however, is not anatomic and will not give satisfaction to a high-demand athlete.

Primary repair of the interstitially torn ACL is sometimes adequate. The work of Marshall et al.⁸ and Sherman et al.³ presents a good argument for primary repair when the repair is located proximally and the patient’s demands are minimal—age is not a discriminator. The interstitial nature of the torn helicoid ACL, the scant blood supply, and the hostile nature of the intercondylar notch all make it difficult to perform a primary repair that will restore vascularity and tensile strength. Augmentation grafting has been the procedure of choice for young patients with athletic demands.

Nevertheless, with improvement in MRI diagnosis and with an understanding that proximal tears do occur, especially in skiing, there has been a re-emphasis on primary repair and “healing response.” This is discussed by Dr. Steadman in detail in Chapter 8 of this book. To support the selectivity in the care of the patient, I have seen excellent results from both primary repair and the healing response. In retrospect, one third of the West Point Cadets that we reported in our original study⁹ did well with primary repair. This is especially noteworthy given the activity level of this patient population. Further reflection on this early report supports the need for selectivity in patient care.

ACL surgery today is reliable to the 90th-plus percentile. Reinjury and retear do occur; they present serious problems. This is usually associated with a return to competitive sports and often reflects a reinjury of the magnitude of the original injury.

The other bedeviling complication is arthrofibrosis—limitation of motion and patellar capture. This complication has been under appreciated but is reflected in long-term morbidity. A flexed knee gait will not be accepted by the patient for long. Furthermore, capture of the patellofemoral joint through scar tissue, adhesions, and loss of the anterior interval take a toll on the patella through compression arthropathy. The physician must be alert to this complication, and be able to manage it through rehabilitation and/or arthroscopic debridement and release. I must counsel the patient both pre- and postoperatively regarding this possibility. Complications will be discussed in detail in Chapters 11 and 12.

This case involved an 18-year-old outstanding athlete who sustained an “isolated ACL” during an athletic competition. The patient elected surgical repair and the central third of the patellar tendon was used for augmentation grafting. A high level of confidence in this operation by close supervision and a thorough rehabilitation program is essential to success.

The long-term results for patients treated in this manner have been excellent. The operation has proved to be reproducible. Rehabilitation, both short-term and long-term, has been stressed until strength, endurance, and agility are restored. Bracing, return to competition, and complications are discussed in Part II of this book.

A 21-year-old college junior, a first-string running back, was struck on his planted right leg while advancing the ball. He experienced severe pain and did not attempt to rise from the turf. The examination revealed gross laxity and he was helped from the field with the leg well-splinted.

This case represents the classic injury of American football as described by O’Donoghue.¹⁰ This “triad injury” became more frequent through increased efficiency of the helmet, contact below the waist (the “crack-back block”), and enhanced fixation of the shoe-turf interface. As both the speed of the game and the force of impact increased in the late 1950s, these injuries became all too common. Game films allowed analysis of the disruptive forces that were applied to the knee through this classic mechanism. Peterson (O’Donoghue Presentation at the American Orthopaedic Society for Sports Medicine meeting, Lake Tahoe, CA, 1981), through study of game films and the injury pattern, promulgated rule changes that have been responsible for a marked decrease in this devastating injury. Regretfully, though, these devastating injuries still occur with regular frequency.

Since this patient has a chance at a professional sport future, he would be called an “elite” athlete. The next season was important to both player and coach. Because of the serious nature of the injury and the future prospects, it is important that planning proceed expeditiously and thoroughly.

The patient was scheduled for surgery the morning after injury, and the knee had been amply iced as well as splinted immediately subsequent to the injury. The “first team” was assembled for the operative procedure. A detailed examination under anesthesia is important so that maximum use can be made of arthroscopic repair and the incisions minimized. All disrupted structures must be repaired. A diligent intraoperative physical examination at each stage of the repair will verify the restoration of stability and ensure that a ligamentous lesion has not been overlooked.

Examination under anesthesia is a part of the operative care. It is performed immediately after induction of anesthesia, before the leg is prepared, in comparison to the well leg, and before the tourniquet is inflated. Besides the obvious laxity, the surgeon searches particularly for induration at the posterior corners of the meniscal ligamentous complexes and the limits of motion of the joint anteriorly, posteriorly, and in rotation. The stable hinge is important to define. The C-arm should be available to the operating room to verify laxities and resolution of the appropriate surgery as necessary.

Complete interstitial tear of the ACL requires augmentation grafting. Frequently, in severe cases of this nature, I use an allograft to limit surgical dissection. The patient must be thus counseled as to this preference.

The meniscal attachments are carefully defined at arthroscopy. The meniscotibial and meniscofemoral attachments are important for stability. Definition of the posterior oblique ligament as it attaches to the meniscus must be determined and repaired. The question becomes, what is the most expeditious order to repair the components?

Furthermore, care must be taken to ensure that there are no chondral lesions, and if these are present, they should be addressed as appropriate to their extent and depth (see Chapter 9). It is obvious in this case that a limited incision will be required (Fig. 3.2.4A–B) in order to repair the medial collateral ligament and the posterior oblique ligament as well as the meniscotibial and meniscofemoral attachments. Some of this work can be done arthroscopically. This is to be encouraged wherever appropriate. Thus, the goal is an anatomic restoration of the torn structures and this usually requires some open surgery. The secret is to minimize the open surgery through preoperative planning enhanced by physical examination, MRI, and the diagnostic operative arthroscopy.

As regard to sequence of repair, I prefer to prepare the ACL tunnels for femoral and tibial insertion as a first step. Allograft will materially decrease postoperative morbidity. Then, prior to tensioning and fixation of the ACL, I address the meniscus and medial capsuloligamentous structures. Here it is important to define the posterior oblique ligament, which intimately attaches to the meniscus, from the medial collateral ligament, which is not attached to the meniscus. It is also important to restore the meniscotibial ligaments and their attachments of the semimembranosus. Repair of medial structures should be accomplished according to the theoretical course of the medial collateral ligament (the line of the Burmester curve), as described by Mueller (Fig. 3.2.5).¹² Subsequent to repair of these structures, the ACL is tensioned and fixed. (For details, see Chapter 8.)

Tourniquet time should be minimized. In the postoperative course, pain is decreased when tourniquet time is kept to the minimal. Also, the muscle tissues and the neurovascular structures sustain minimal damage.

Patient postoperative pain is a major concern to the surgeon. Techniques for postoperative pain are discussed in Chapters 3 (Case Study 1) and 8. Compression bandage or elastic stocking is applied firmly. Cryotherapy is a critical component of postoperative patient care. Also, I prefer that the patient use continuous passive motion (CPM). We usually begin with 20 degrees to 70 degrees of motion. The patient is usually hospitalized for 1 or 2 days subsequent to the surgical procedure.