Tweet
Following the ACL question (copied below as poated on Biomch-l) concerning
the relationship of mechanism of injury to womans sport I offer my 2cents
worth and maybe some stimulation of discussion.
With respect to mechanism of ACL injuries it is important that we really
consider the functional action of the ACL during activity rather that how
it functions on the clinical bed. Sure Lachmanns test and the ubiquitous
anterior draw do test the integrity of the ACL but don't relate too well
to the mechanism of injury. I have never seen an ACL torn when the lower
leg segment is essentially free of contact from the ground. The action of
the ACL in a "closed kinetic chain" with the foot firmly fixed on the
ground is to prevent the femur from falling off the postero-lateral corner
of the tibial plateau - which I agree is also relative anterior
translation of the tibia on the femur. However if you act out the
mechanism or have those with "fond" memories of the action that tore their
ACL they will certainly describe a fixed foot plant with the femur and
trunk moving on that fixed lower leg segment. If you look at most texts
they describe the action of ACL relative to the tibia moving on the femur.
Even Kapandji's "Physiology of the joints" relates it that way but in
function even with walking the ACL are involved in ensuring the approriate
amount of roll, spin and glide of the femoral condyles on the tibial
plateau.
This concept must also be remembered when designing rehab programs for ACL.
Regards,
Peter H.
************************************************** *************************
Peter Hamer Department of Human Movement, and
DipPhys, BPE(Hons), MEd, FASMF Department of Anatomy and Human Biology
PhD Student University of Western Australia
Nedlands 6008
Western Australia
E-Mail: phamer@uniwa.uwa.edu.au Ph: +61 9 380-2361 (w) extn. 1385
************************************************** *************************
On Fri, 7 Apr 1995, by way of cronshaw@rain.org Paul Cronshaw, D.C. wrote:
> > > It is very important to find out the mechanisms for ACL injuries
> > >because if the number of incidence keeps growing, it might become a
> > >possible threat to female athletic community in the near future.
> > >
> > > I appreciate your help.
> > >
> > >Satoshi Fujita
>
> Just happened to have some info from Campbell's Othopedics;
>
> p 1568- Selective sectioning of the anterior cruciate ligament has
> shown that the anteromedial band is tight in flexion whereas the
> posterolateral bulky portion of the ligament is tight in extension
> (see fig. 33-82,D). It has been shown that the anteromedial band is
> the primary check against the anterior translation of the tibia on
> the femur when the anterior drawer test is performed in the usual
> manner with the knee flexed. With the knee extended, resistance the
> anterior drawer is by the posterolateral bulky portion. Marshall
> has shown that it is possible to obtain an anterior drawer sign and
> yet at the time of surgery palpate an "intact" anterior cruciate
> ligament. When the anteromedial band of the ligament is torn, the
> posterolateral bulk of the ligament may remain intact and an
> anterior drawer sign will be present but the surgeon will have the
> impression that the ligament is not torn. The anteromedial and
> intermediate parts of the anterior cruciate ligament are in direct
> contact with the intercondylar shelf in extension, and rupture
> commonly occurs in this middle third of the ligament when the knee is
> forced into hyperextension (fig. 33-85). The posterolateral
> portion of the anterior cruciate ligament provides the principal
> resistance to hyperextension of the joint. The ligament also aids
> in limitation of rotation of the tibia on the femur as well as
> resisting extreme varus and valgus stress.
> D.W. Smith, D.C.
> Santa Barbara Health Center
> e-mail: dwsmith@rain.org
> http://rain.org/~dwsmith
>
the relationship of mechanism of injury to womans sport I offer my 2cents
worth and maybe some stimulation of discussion.
With respect to mechanism of ACL injuries it is important that we really
consider the functional action of the ACL during activity rather that how
it functions on the clinical bed. Sure Lachmanns test and the ubiquitous
anterior draw do test the integrity of the ACL but don't relate too well
to the mechanism of injury. I have never seen an ACL torn when the lower
leg segment is essentially free of contact from the ground. The action of
the ACL in a "closed kinetic chain" with the foot firmly fixed on the
ground is to prevent the femur from falling off the postero-lateral corner
of the tibial plateau - which I agree is also relative anterior
translation of the tibia on the femur. However if you act out the
mechanism or have those with "fond" memories of the action that tore their
ACL they will certainly describe a fixed foot plant with the femur and
trunk moving on that fixed lower leg segment. If you look at most texts
they describe the action of ACL relative to the tibia moving on the femur.
Even Kapandji's "Physiology of the joints" relates it that way but in
function even with walking the ACL are involved in ensuring the approriate
amount of roll, spin and glide of the femoral condyles on the tibial
plateau.
This concept must also be remembered when designing rehab programs for ACL.
Regards,
Peter H.
************************************************** *************************
Peter Hamer Department of Human Movement, and
DipPhys, BPE(Hons), MEd, FASMF Department of Anatomy and Human Biology
PhD Student University of Western Australia
Nedlands 6008
Western Australia
E-Mail: phamer@uniwa.uwa.edu.au Ph: +61 9 380-2361 (w) extn. 1385
************************************************** *************************
On Fri, 7 Apr 1995, by way of cronshaw@rain.org Paul Cronshaw, D.C. wrote:
> > > It is very important to find out the mechanisms for ACL injuries
> > >because if the number of incidence keeps growing, it might become a
> > >possible threat to female athletic community in the near future.
> > >
> > > I appreciate your help.
> > >
> > >Satoshi Fujita
>
> Just happened to have some info from Campbell's Othopedics;
>
> p 1568- Selective sectioning of the anterior cruciate ligament has
> shown that the anteromedial band is tight in flexion whereas the
> posterolateral bulky portion of the ligament is tight in extension
> (see fig. 33-82,D). It has been shown that the anteromedial band is
> the primary check against the anterior translation of the tibia on
> the femur when the anterior drawer test is performed in the usual
> manner with the knee flexed. With the knee extended, resistance the
> anterior drawer is by the posterolateral bulky portion. Marshall
> has shown that it is possible to obtain an anterior drawer sign and
> yet at the time of surgery palpate an "intact" anterior cruciate
> ligament. When the anteromedial band of the ligament is torn, the
> posterolateral bulk of the ligament may remain intact and an
> anterior drawer sign will be present but the surgeon will have the
> impression that the ligament is not torn. The anteromedial and
> intermediate parts of the anterior cruciate ligament are in direct
> contact with the intercondylar shelf in extension, and rupture
> commonly occurs in this middle third of the ligament when the knee is
> forced into hyperextension (fig. 33-85). The posterolateral
> portion of the anterior cruciate ligament provides the principal
> resistance to hyperextension of the joint. The ligament also aids
> in limitation of rotation of the tibia on the femur as well as
> resisting extreme varus and valgus stress.
> D.W. Smith, D.C.
> Santa Barbara Health Center
> e-mail: dwsmith@rain.org
> http://rain.org/~dwsmith
>