Diagnosis and Treatment of Injury to the Anterior Cruciate Ligament *

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1 /81/ $02.00/0 THE JOURNAL OF ORTHOPAEDIC AND SPORTS PHYSICAL THERAPY Copyright O 1981 by The Orthopaedic and Sports Physical Therapy Sections of the American Physical Therapy Association Diagnosis and Treatment of Injury to the Anterior Cruciate Ligament * DON H. O'DONOGHUE, MD In the course of discussion of the anterior cruciate ligament, we ought to separate and define it from the other groups of ligaments which provide stability to the knee. A brief anatomical discussion is important to bring this into proper perspective, even at the expense of some repetition with other authors. The anatomical structure of the knee joint puts it at an immediate disadvantage in respect to injuries to the ligaments. While in the hip there is a ball and socket joint which has a good deal of stability and in the ankle there is a mortise and tenon which provides a good deal of lateral stability, the knee is basically a junction of two long bones approximately in the middle of the extremity, with little stability in so far as the bone is concerned. Some bony stability is provided by the fact that the femoral portion of the knee is a bipod which gives much more bony stability than if it were a single condyle, so that in order to get lateral instability one of the feet of the bipod must actually be lifted off the tibia. No such stability, however, is provided for anterior/posterior motion. The mechanism, then, that gives stability to the knee is a complex of ligaments (Fig. 1 ) which are roughly divided into six groups: the medial ligaments; the medial posterior capsule; the lateral ligaments; the lateral posterior capsule; the anterior cruciate ligament; and the posterior cruciate ligament. This ligament complex, supported somewhat by the menisci, does have a system of mutual support which essentially gives excellent stability to the knee. The anterior cruciate ligament, with which we are particularly concerned here, has a primary function of preventing anterior displacement of the tibia on the femur. It is aided in this function by both collateral groups but particularly by the medial collateral ligaments, so that there can be clinical stability in the anterior plane with an absent anterior cruciate ligament, simply by the fact that the medial collateral ligaments (and the From the O'Donoghue Orthopaedic Clinic, Pasteur Medical Building, Oklahoma City, OK opposite lateral ligaments) are intact. This does not in any way downgrade the function of the anterior cruciate ligament since, although the knee can function without the anterior cruciate ligament, its ability to resist forces is very much diminished. Many tests have shown that it is the primary stabilizing factor in preventing anterior displacement of the tibia on the femur. The various combinations of instabilities which tend to bear this out would be concerned primarily with the anterior cruciate ligament. The anterior cruciate ligament rises from the nonarticular portion of the anterior segment of the upper end of the tibia, extends backward and somewhat laterally, to attach to the posterior portion of the intercondylar notch, back as far as the margin of the articular cartilage. This course from front to back does resist forward displacement of the tibia. Of course, in any discussion of knee ligament conditions, particularly injuries, it is very difficult to separate one structure from the remaining supporting structures. True enough, there may occasionally be an "isolated" tear of the anterior cruciate ligament (although this is debatable), but in the majority of instances the anterior cruciate ligament is torn in conjunction with other ligament tears. It very commonly tears in conjunction with the medial collateral complex since these two ligaments do have somewhat the same function. Other rotatory forces may tear the anterior - cruciae. The deeper'gps;;i%-feffeof the _ ^_ collateral ligaments may give way, and by rotat i o 8 a t e can be torn. So much tor the ph~losophy of the -c function of the anterior cylcrate ligament. As in almost all conditions of the knee, the single most important element in treatment is diagnosis. It is exceedingly difficult to treat a knee if one does not know what is wrong with it, and this certainly applies to the anterior cruciate ligament. Many factors will tend to minimize errors in this respect. As previously mentioned, the isolated tear of the anterior cruciate may be

2 JOSPT Winter INJURY TO THE ANTERIOR CRUCIATE LIGAMENT 101 Fig. 1. Anatomical drawings of the knee. A, anterior view; patellar tendon is sectioned and the patella reflected upward; knee flexed; note that the cruciate ligament rises in front of the anterior tibial spine, not from it; note also that the medial meniscus is firmly attached to the medial collateral ligament; B, posterior view; knee extended; note that the posterior ligament has been removed; the two layers of the medial collateral ligament are shown diagrammatically, as well as the tibial portion of the lateral collateral ligament; the posterior cruciate ligament rises behind the tibia, not on its upper surface; observe the femoral attachment of the anterior cruciate ligament at the back of the notch. From O'Donoghue' (Fig. 438). extremely difficult to diagnose since, by virtue of the fact that it is said to be an isolated tear, there may be no instability in the knee at all. There are, however, certain elementary findings that are extremely important. This is where the history of the patient is so important in diagnosis of any condition about the knee. A history.of a cutting or twisting injury, such as a player running down the field and cuttincl sharoly, with the knee g?ving way, the presence of an audible pop, followed by~an early and quite definite nemarthrosis, considerable oain in the knee, and difficulty -walking, makes one - s &-r cruciate injury. Clinical testing of this knee may show complete collateral and anteroposterior stability to ordinary testing since the collateral ligaments have taken up the task of preventing anterior displacement in the tibia on the femur. Checking for anterior motion of the tibia on the femur can be accomplished by the drawer test (Fig. 2). This should be compared with the normal opposite knee, since there may be some anterior motion normally present. This can be confirmed by lateral X-ray of the knee joint (Fig. 3) in which a similar test is done. Another test which can be made without flexing the knee as much is made with the patient supine, the knee flexed about 30" or less. Grasp the upper leg with one hand and the lower thigh with the other hand and simply push down on the thigh and pull up on the leg. This requires a fairly good sized grip and may be difficult to do on a large athletic knee. Aspiration of the hematoma may provide a clue, particularly if it is a true hemarthrosis and not just an effusion. At this point, the diagnosis may, indeed, be helped by arthroscopy, although arthroscopy under these circumstances is exceedingly difficult because it is difficult to get a bloodless field, even though the knee is washed out quite thoroughly. Here again, the experienced arthroscopist may well detect injury to the cru-

3 102 O'DONOGHUE JOSPT Vol. 2, No. 3 ciate, the problem being that sometimes the cruciate injury may be screened by an overlay of synovial tissue which makes it seem intact when actually it is torn. Fig. 2. The drawer sign. The patient sits with the leg dangling from the table. The examiner is seated in front of the patient with the foot clasped between his knees, hands as shown. Forward pressure will demonstrate anterior cruciate instability; backward pressure, posterior cruciate instability. This motion should be made by slow steady pull rather than by a succession of jerks, which will be painful to the injured knee. The inset shows a positive anterior drawer sign, the tibia sliding forward and downward in relation to the normal position. From O'Donoghuei (Fig. 450). The reason that this particular diagnosis is important is the fact that proper treatment of the torn anterior cruciate is surgical. It is generally agreed that if the cruciate is torn, it should be repaired; also, if it is repaired, it should be repaired early, at most before 2 weeks because the ligament ends do not remain discrete when they are flapping around in the joint. They will pull back and begin to appear as cartilage, beyond the possibility of acute repair. Here again, there is some argument about when the repair should be done. It is best that any time one finds a torn anterior cruciate ligament, which is repairable, whether the tear be at the femur, at the tibia, or in the central fibers, repair should be done. If one is doing an arthrotomy, it adds very little to operative time and certainly is worth a trial. Admittedly, a tear in the center part of the ligament heals less well, but it certainly will not heal if it is not repaired. If it is pulled off the femur, the results seem to be better although, if it comes off the tibia with a segment of bone, that is probably the most favorable type. The difficulty in these cases is to analyze the end result because, if the knee was not unstable to start with, the fact that it is still stable after rehabilitation does not necessarily mean that the treatment has been effective. The Only sure way to know this ~ould be to perform an arthrotomy to examine the ligament or to do an arthroscopy. Fig. 3. X-ray appearance of positive anterior drawer sign. This 15-year-old female fell while doing acrobatics and twisted her knee. She had a torn anterior cruciate ligament with injury to the medial collateral ligament and medial meniscus. A, lateral, with posterior stress-negative; B, lateral, with anterior stress shows tibia far forward, indicating loss of the anterior cruciate ligament. From O'Donoghuei (Fig. 451).

4 JOSPT Winter INJURY TO THE ANTERIOR CRUCIATE LIGAMENT 103 Again, our justification for arthroscopy is in analyzing and determining postoperative results. In the patient who has no complaint and whose knee is not unstable or giving him any problem, it is very difficult to request that patient to have an arthroscopy simply to confirm postoperative findings. To sum up, the "isolated" tear probably presents the most diagnostic difficulty although it is the least common. Statements have been made, however, that a high percentage of medial meniscus tears will reveal anterior cruciate damage. If this is true, it is more pertinent (as suggested in another area) to operate early on a meniscus injury as soon as one knows the meniscus is torn because one then has the opportunity to repair the torn anterior cruciate ligament. That is another push toward early arthrotomy in this type of acute injury. To get to the more common, or at least the more recognized, type of anterior cruciate injury, we must turn to the diagnosis of the injured knee which can be a very complicated problem indeed. As stated before, anterior cruciate damage very often accompanies medial collateral ligament damage and, in fact, is probably more the rule than the exception. With the so-called "triad" injury, where the medial collateral ligament is torn and there is definite medial side instability, the anterior cruciate is probably also torn. In this instance, however, there usually will be anterior instability because the main structure preventing anterior displacement of the tibia on the femur and also its back up, namely, the medial collateral ligaments, are torn. It is still best that, if there is complete tear of any ligament in the knee which is demonstrable, it should be repaired. This is particularly true in injury of the collateral ligaments where, if there is gross instability at the time of the original examination, this instability is not going to lessen after several weeks in a cast. In fact, it may actually increase a bit because the pain element is eliminated. Therefore, it is exceedingly important (to digress a moment from the anterior cruciate) in medial collateral ligament injuries to do an early and adequate repair. This has been found to be very satisfactory functionally, much more satisfactory than in any of the reconstruction procedures we have available. The dividend to this also is the fact that usually the anterior cruciate ligament will be found to be torn and occasionally also the posterior cruciate. There is no way that this can be demonstrated without an arthrotomy. Since tear of the medial ligaments demands arthrotomy anyway, it behooves the surgeon to carefully inspect the inside of the joint, determine the status of the cruciate ligaments, and repair whatever pathology is found. Fortunately, the usual lesion is off the femur or at least toward the femoral end of the cruciate ligament. We have found that the best method for repair of this is through parallel drill holes through the lateral femoral condyle which will accommodate mattress sutures through the cruciate ligament (Fig. 4). True enough, many times the cruciate ligament will be shredded out and does not retain the sutures well, but after all, the sutures do not have to do any more than hold the fibers together since the postoperative immobilization presumably will prevent undue Fig. 4. Repair of the anterior cruciate to the femur. A, drill holes being made from inside the joint to emerge on the lateral epicondylar ridge and a second incision; B, illustration of the direction of mattress sutures for the cruciate ligament. From O'Donoghue2 (Fig. 8).

5 104 O'DONOGHUE JOSPT Vol. 2, No. 3 stress on the ligament. Even in cases where one may have some question about the stability of his suture, by multiple threads and multiple loops of suture, one can get enough fixation to at least pull it back where it belongs. Sometimes, it may be a little short, and in such case, it could be placed just a little bit anteriorly. However, the further posterior the repair, the better function is obtained in the ligament. If the ligament is torn off the tibia, with or without a block of bone, the drill hole is made from the front of the tibia up into the bed from which the ligament was torn. Suture is passed through this, mattressed through the ligament, and pulled back through a separate drill hole (Fig. 5). This has proven to be a very effective means of holding the ligament. The problem case is the one in which the ligament is torn in the middle. This is often the case, and there is not enough segment, either femoral or tibial, to reach back to the proper place. There are several methods of fixation for these cases. Probably the best one is the multiple suture technique, by mattressing suture through the femoral fragment and through the tibial fragment, encompassing the diameter of the ligament. When these are tied, it tends to pull the ligament ends together. Sometimes, this Fig. 6. Application of long leg stirrup splints. Note that the extremity is supported constantly by the foot and the thigh, permitting the tibia to drop backward and relax the anterior cruciate. A, a heavy posterior splint is applied first, wrapped with gauze, and allowed to harden a little; B, the lateral splint is then applied and wrapped with gauze; a separate short stirrup is used to grasp the foot. From O'Donoghue' (Fig. 444). Fig. 5. Repair of the anterior cruciate ligament to the tibia. Note there are two separate mattress sutures, one about 1 centimeter back into the ligament, while the anterior one is at the anterior edge of the tear. The function of the deeper posterior mattress suture is to flatten out the end of the ligament against the denuded top of the tibia in order that there will be good contact of ligament to raw bone. The same maneuver can be used if there is a fragment snugly in the vascular bed of the tibia. From O'Donoghue2 (Fig. 9). Fig. 7. Application of long leg cast. Note that the extremity is supported by the thigh and the foot to permit the tibia to drop backward to relax the anterior cruciate. A, posterior plaster slab; B, the completed cast with the foot in slight eversion, the ankle neutral, the knee at 20'. To balance the pelvis, the patient should have a shoe with a heel of equal height on the good leg. From O'Donoghue' (Fig. 446).

6 JOSPT Winter INJURY TO THE ANTERIOR CRUCIATE LIGAMENT 105 looks very satisfactory, and sometimes, it looks very tenuous. An alternate method is by double mattress sutures through the femur and tibia, crossing at the defect. One should make a distinct effort to wrap the fat pad around the repaired ligament as far as it will reach. In cases where it is off the femur, it is difficult to get it back that far. Certainly in cases where it is off the tibia and in the middle third, this does give additional support and blood supply. This is not the proper place for details of surgical technique but the above outline of the general methods available seems appropriate. Aft_.- is extremely important and extremely pertinent. t_o a discussioa.ta physlcal t&raplsts and trainers. One needs to have a distinct pattern for rehabilitation which begins, of course, with the aree of-fixation. Use of a solid cast after an acute ligament injury is successful only if it is intended to be changed very shortly. Instead, it is best to use a heavy posterior splint with a lateral stirrup, one going from the groin down around the ankle and up to the trochanter, with another one, stirrup-like, including the front of the foot by the use of a separate short stirrup grasping the foot (Fig. 6). This is open down the front. It can be wrapped on very snugly and can be split down the front if the swelling is gross. The more pertinent thing is to keep it tight all through this period while the leg stabilizes in size. After the leg is stabilized in size, the splint can be removed, the sutures removed, and a long leg cast applied (Fig. 7). Care is made to support the extremity by the thigh and by the foot so that the tibia tends to fall backward rather than forward. With great care to detail, this can be satisfactorily accomplished. Some recent work has indicated that there is excess motion within any cast, and this is to some extent true. The question is whether that degree of motion is going to hazard the repair. A long leg cast is worn until 8 weeks postoper- \ ative. but this may require the use of a splint for 2 weeks and 2 casts for 3-week m s for each. On the day of surgery, we have instructed the patient before the operation what we expect him to do postoperatively (Fig. 8) and he is expected to practice quad tightening and continue this on the next day. He can stand on crutches if it is necessary but should not put weight on it. He then proceeds with a progressive schedule of exercises which are isometric since he is in a long leg cast. He is encouraged also to exercise his arms and the opposite leg. This is a very critical time when the cast is removed because Tt is important for the patient to continue w a m n crutches w~th toucn-down weight oearing until his range of mot~on rias improved to ap~roximately 90" of flexion and -P extension. It is difficult to get this point across to a young athlete, but great emphasis should be placed here. He should not be in a cast in which he walks independently following an acufe mament repair although he can touch down with crutches without undue stress. During th-e 6 weekstn The cast, following 2 weeks in the splint, if the cast becomes loose it should be changed. There is no question about this. It should be changed. If a hand can be placed in the cast above, at the thigh area, it is far too loose. A lot of this can be prevented if the patient will exercise the quad to the point where he is raising 15, 20, or 30 pounds, and the thigh is not likely to atrophy so much. In any event, he should not be allowed to go 6 weeks in the cast without recheck because it may get so loose that it is not maintaining stabilization. We have not utilized the various internal fixation methods although suggestions have been made such as cross pins to stabilize the knee or extension or flexion apparatus with pins through the tibia and femur. This seems to add considerably to the morbidity and is not ordinarily advisable. The rehabilitation period will vary greatly according to the personality of the patient and the extent of the injury. It may be several months before he is able to attain a normal range of motion. We do not permit athletic competition under 6 mhs. -hen they do go back to athletic competition, the athletes should be adequately braced. We usually do not use the Lenox Hill type brace at this point unless there is some demonstrable instability. Various types of the corset brace with metal stays give some degree of protection. The degree of flexion in which the knee is placed postoperatively has not been specified, and there is a good deal of difference of opinion about this. We put our patients between 30 and 40' of flexion in the splint. When the splint is removed and extension is readily permissible, flexion is possible at 30" in the long leg cast. Weight bearing in a long leg cast with the knee at 30" puts a great deal of stress on the knee so we do not encourage full weight bearing at this

7 O'DONOGHUE JOSPT Vol. 2. No. 3 BRING THIS SHEET WITH YOU ON EVERY VISIT Each of the following exercises should be done deliberately and to a particular count. In each instance, raise the involved leg slowly to the count of 3, hold to the count of 3, lower to the count of 3, and rest. Repeat this 30 times total. The exercises should be repeated two or three times a day, depending upon your tolerance. 1. Lying on the back, raise the leg up with the knee straight and not flexing. 2. Lie on the unaffected side. Raise the involved leg up with the knee straight. 3. Lie face down. Raise the leg up with the knee straight. While you are still in the splint or cast, when you are able to complete the series of 30, then start a new series, using 2 pounds of weight, and gradually increasing the weight as.your strength improves. Build this weight up to at least 25 pounds, if possible. Chart your daily progress and record it. It is very important that these exercises be done exactly as described. Exercises 1, 2 and 3 should be done while the leg is still in a splint or cast and should be continued after the cast is removed. When your cast is removed, procede as follows: 4. Sitting with the leg hanging and the knee at a right angle, gradually work up to a series of 30, with spring resistance or weight. If there is ligament damage, a spring or system of pulleys and weight is preferable rather than to hang the weight on the foot. 5. Lie face down with weight on the foot, flex the leg to vertical through the same series. 6. As ynur condition improves, other exercises should be added such as stair climbing, partial knee bends, single knee bends, etc. In general exercises 4, 5 and 6 should not be done when there is extensive fluid or blood in the joint. You are to continue the exercises until the involved thigh is (A) as large as the normal side. (B) as strong as the normal side. (C) Normal motion is reached. IF YOU DO NOT UNDEKSTAND THESE EXERCISES, PLEASE INQUIRE. If you lose this sheet and need another, a charge of $1.00 will be made for each additional sheet. Fig. 8. Typical set of exercises used for rehabilitation. This is adjusted according to the individual requirements of each patient. From O'Donoghuel. time. If it is necessary to change the cast at some point in the interim and if the knee will go out to 20, it is placed in this position although it should not be pushed. The rehabilitation after the cast is off presents three problems: 1) to get a range of motion in flexion; 2) to get a range of motion in extension; and 3) to build muscle mass. This can be accom- plished by isometric exercises or isotonic ones. Isotonic exercises are not encouraged if there is effusion, a lot of swelling in the knee, or pain on motion. We do encourage straight leg raising from the beginning. This is a brief discussion of my feelings about the anterior cruciate ligament which has been of concern to me for at least 40 years. Sometimes,

8 JOSPT Winter the results are dramatically good and very gratifying. Sometimes, without knowing exactly why, the result is poor. But, there are some things that I have found in the course of the years that I think are important; that is, the reoair s W &e early, it should be comolete (i.e., every ligament that is completely torn should be repaired), and then it should be carefully protected for several months postoperatively. We do not have any satisfactory material to extend through the knee as a prosthesis. To use a strip of the patellar tendon routinely is not justified. The strip is not long enough, and it adds materially to the oper- INJURY TO THE ANTERIOR CRUCIATE LIGAMENT ation. Maybe some time, we will have replacement materials that the knee will tolerate. Early complete repair of every damaged ligament is the rule. Just because it may not heal is no excuse for not repairing the anterior cruciate. If only 10% of them heal, it would be worth the procedure, and certainly more than that do heal. REFERENCES 1. O'Donoghue DH: Treatment of Injuries to Athletes, Ed 3, pp 559, and 573. Philadelphia: WB Saunders Co O'Donoghue DH: Surgical Techniques for Acute Knee Injury, Operative Surgery, Ed 3, p London: Butterworths, 1976