[quote=Velodog2;784444]One question it didn't seem to answer was whether an aclr knee was more likely to be injured than a non-aclr knee. I guess that's just a given or proven in a butt-load of other studies, but I'd like to know how much more likely it was. I would also like to know the effect of having a pre-season abnormal lachman or pivot-shift on the probability of being injured.
Here's some more data I drummed up. If you search for "abnormal lachman or pivot-shift" you'll find lots of references:
The second article (Kocher et al) we read was another study involving skiers with ACL-deficient knees. Kocher et al studied 180 subjects, considerably more than Nemeth et al. We hoped that this larger number of subjects would strengthen the conclusions that Kocher et al discussed.
J Knee Surg
Kocher MS, Sterett WI, Briggs KK, Zurakowski D, Steadman JR. Effect of functional bracing on subsequent knee injury in ACL–deficient professional skiers.
. 2003 Apr;16(2):87–92.
The effect of functional bracing on subsequent knee injury in anterior cruciate ligament (ACL) deficient professional skiers was evaluated. A cohort of 180 ACL-deficient skiers was identified from a knee screening of 9410 professional skiers from 1991–1997. An ACL-deficient knee was defined by an abnormal examination (Lachman or pivot-shift) and a
5-mm KT - 1000 manual maximum difference. The dependent variable was subsequent knee injury, which occurred in 12 knees. A significantly higher proportion of injuries occurred in nonbraced skiers compared with braced skiers (P=.005). The risk ratio for subsequent knee injury comparing nonbraced with braced skiers was 6.4 (13% and 2%, respectively). Univariate analysis revealed no significant effects of the other covariates. Logistic regression identified bracing status (P<.01; odds ratio=8) and KT-1000 manual maximum difference (P=.02; odds ratio=1.3) as significant multivariate risk factors for subsequent knee injury, controlling for covariates.
[© 2003 Slack Inc. Abstract reprinted with permission of Slack Inc.]
This study took place from 1991 to 1997 at a major ski resort where a total of 9,410 employees who were professional skiers underwent annual screening exams for their knees. Of the 9,410 subjects screened, 180 skiers had an ACL-deficient knee, as defined in the abstract. Their mean age was 38.6 years. Because our 47-year-old patient had an ACL-deficient knee with abnormal Lachman test results, we felt that he was similar in age and knee pathology to the subjects studied in this article. The study participants skied a minimum of 80 days per season, which was substantially more than our patient expected to ski.
After skiers were determined to have an ACL-deficient knee, the researchers conferred with a physician, who considered individual preference and willingness to wear an FKB in making a bracing decision. Based on physician recommendations, 101 skiers received a custom-fit knee brace, and 79 skiers did not receive a brace. The braced and unbraced skiers did not differ in age, occupation, or results of Lachman or pivot shift tests. The braced skiers, however, demonstrated greater laxity on instrumented testing than nonbraced skiers. Any subsequent knee injury, defined as an injury that prevented the person from working, was traced through workers' compensation claims. The results of the study showed that the skiers who were not braced had a higher proportion of subsequent knee injuries than the braced skiers did. Two of the 101 braced skiers and 10 of the 79 unbraced skiers sustained subsequent knee injuries, which corresponded to a risk of subsequent knee injury that was 6.4 times higher for nonbraced skiers. Despite the fact that instrumented testing indicated greater laxity in the group that was braced, the group that was unbraced had more knee injuries.