The ligament of Humphrey and fat on the PCL must be taken into account in this measurement. This is impor- tant to know when preparing the length of the semitendinosus and patellar tendon grafts. The total length of the tibial tunnel, the intra- Natural History of ACL Injuries 5 articular length, and the femoral tunnel must be compared to the graft length to avoid mismatch in the endoscopic reconstruction. This calcu- lation avoids protrusion of the graft on the tibial side.
The overall length of the graft is 9 to 10 cm. The data come from patients who came to the Kaiser emergency room in San Diego with knee injuries.
Anterior Cruciate Ligament (ACL) Injuries - OrthoInfo - AAOS
Many authors have stated that the ACL injury is career ending for the athlete and that the knee will embark on a course of progressive degeneration. Noyes, however, reported in on a group of sympto- matic patients that he placed on a conservative program of exercise, bracing, and activity modification. This group was followed for at least 5 years. The medial tear is more common in the chronic situation. The younger patient did not fare as well as the older patient.
The more pivotal sports, such as basket- ball, volleyball, and soccer, had a higher incidence of inability to par- 6 1. Introduction ticipate after an ACL injury. This was also related to the level of com- petition and the number of hours of sports participation. Daniel also determined that with more a-p laxity, the functional level of the athlete decreased. He advocated an objective measurement of the laxity with the KT arthrometer.
With more than 7 mm of difference and a gross pivot shift examination, he suggested surgical reconstruction. The athlete is simply running and abruptly changes direction.
The athlete lands in the flexed posi- tion, the quadriceps contract, and the tibia is subluxed anteriorly. Then with further flexion, the tibia reduces with a snap.
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This is the same mech- anism that the pivot-shift test mimics. Barrett and coworkers have calculated that an eccentric quadriceps con- traction can generate up to N. This far exceeds the strength of the ACL at N. This force can be observed in basketball in the jump- stop landing.
This position can be reviewed in the video of the badminton player.
However, some additional unrecognized factor must be involved in this mechanism. Many athletes have done that particular move a thousand times without injury. Then, one particular time, the ACL tears. Barrett and coworkers have reproduced this mechanism of active quadriceps contraction in the laboratory.
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In the video, the cadaver knee is clamped, the quadriceps mechanism is held with the dry ice clamp. Gender Issues 7 and the force of pulling on the quadriceps subluxes the tibia forward and ruptures the ACL. The next sequence shows the ruptured ACL. The last sequence demonstrates a positive Lachman test on the specimen. In summary, the body and knee must be in the correct position, the quadriceps must contract strongly enough to sublux the tibia, and the hamstrings fail to protect the anterior subluxation. Can this be prevented? Perhaps by neuromuscular, proprioceptive training, some injuries may be prevented.
Contact Mechanism A common mechanism in football or hockey is the blow to the outside of the knee when the knee is flexed and rotated. Another variation of the contact injury is the internal rotation skiing injury described by Bob Johnson, a doctor from the University of Vermont. In this mechanism, the skier sits back and the ski carves to the inside, producing an internal rotation stress on the knee and a tear of the ACL. Johnson has also described another mechanism that occurs when the tail of the ski hits a bump on the snow and the high ski boot levers the tibial forward, thereby producing an anterior drawer force and tearing the ACL.
Hyperflexion or Hyperextension Mechanisms These less-common mechanisms of injury are often associated with other injuries to ligaments, such as the posterior cruciate ligament. Gender Issues During the past decade, the incidence of ACL injury in female athletes has increased more than the rate in male athletes. Introduction NCAA are 2. The reason is still speculative, but several theories are under investigation.
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Extrinsic Conditioning Many authors believe that the novice female athlete is introduced to activities that are beyond her physical conditioning. Tim Hewett has demonstrated that unconditioned females land from a jump with the knee more extended, and, because of the wide pelvis, in a valgus posi- tion. This extended valgus position puts them at risk for an ACL injury. If slight external rotation is added on landing, then they are in a posi- tion of no return as described by Ireland. Hewett has advocated not only conditioning programs, but also instruction on proper landing posi- tion i.
This is one positive step that can be instituted to reduce the incidence of ACL injuries in females. Muscular Strength Woitys in Griffln et al. The implication is that women should emphasize hamstring strengthening to protect the ACL. Body Movement Arendt and others have documented that most ACL injuries are the result of noncontact mechanisms.
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Hewett has shown that training the female athlete to modify the landing stance to a flexed neutral knee position has reduced the inci- dence of ACL injuries. Intrinsic Joint Laxity There are contradictory studies on the role of ligamentous laxities. It has been documented that exercise produces laxity of the ACL, but there are no signiflcant differ- ences in gender.
Yu et al. The cyclic variation of estrogen may affect the liga- ment metabolism and make females more prone to injury during the estrogen phase of their cycle.
Karangeanes and Vangelos studied the incidence of ACL injury during the cycle of increased estrogen and found no signiflcant difference. Limb Alignment Ireland has emphasized limb alignment the wider pelvis, increased femoral anteversion, and the genu valgum with decreased muscular support, speciflcally the hamstrings, as possible causes for the increased ACL injury rates in women Notch Width Shelbourne and Klootwyk have documented that women have a smaller notch than men.
It has also been reported that athletes who sustain ACL injuries have a narrow notch Fig. It may well be that the narrow notch is only one indication of a small incompetent ligament that is easily torn. Evidence for this is seen after a large notchplasty in which the notch will All in around the new graft. Conclusion At the present time, the best advice to give the female athlete is to be well conditioned and land with a flexed knee. The anatomic variation of wide pelvis, valgus knees and reduced notch width may increase the risk for ACL injury.
Prevention 11 Prevention Johnson believes that if you are aware of the common mechanism that produces an ACL injury, you can help skiers prevent the injury. He has reviewed thousands of hours of on-hill ski injury video and identified a common mechanism that involves sitting back on the skis and trying to recover as one ski carves inward. The Vermont group has produced a videotape on this mechanism of injury and its prevention. His advice is, do not sit back and then try to recover.
Rather, fall to the uphill side. A skier aware of this mechanism may be able to prevent an ACL injury. The phantom foot mechanism and the possible preventive measures have been outlined in a videotape available from Dr. This is followed by immediate pain and swelling of the knee. The athlete may come in walking, with minimal swelling, or on crutches, unable to bear weight. It depends on the associated injuries. In rare situations, the injury that tears the anterior cruciate ligament ACL may be so trivial that the athlete returns to the game. But the next time he pivots on his knee, much more damage, such as a tear of the meniscus, is the result.
This should be the first test performed, so that the patient can be caught while still relaxed. The upper hand controls the distal thigh, while the lower hand, with the thumb on the tibial tubercle and the fingers feeling to ensure that the hamstrings are relaxed, pulls the tibia forward. The feeling on the normal side is a firm restraint to this anterior motion.
The increased excursion on the injured side is noted. When this increased anterior motion is approximately 5 mm and there is a firm endpoint, this should be noted as a l-i- Lachman, with a firm endpoint. This video on the CD demonstrates the Lachman test. In acute injuries. This position also works well for examiners with small hands or when examining a very large leg.