Comparison Between Sexes of Bone Contusion and Meniscal Tear Patterns in Noncontact Anterior Cruciate Ligament Injuries (ACL injuries) Wittstein et al, 2014
This paper aims to investigate whether there is indeed a valgus component to ACL rupture and furthermore whether there is a different mechanism of injury between males and females. A valgus movement refers to the inward bending of your knee that is porposed as a potential cause of ACL ruptures. There is conflicting evidence and research into the primary mechanism that causes a non-contact ACL rupture and whether there is a female predisposition to lean towards this mechanism genetically.
There is previous research that suggests a valgus load (where there is increased load through the lateral/outer boarder of the knee) is the primary component in causing an ACL rupture. There is also previous research to link females with a higher incidence of a valgus load and therefore a higher incidence of ACL rupture.
All ACL reconstructions performed by one consultant between January 2005 and January 2010 were identified. Patients who were under the age of 20, who had an ACL reconstruction for a non contact ACL rupture were included in the study. Their MRI scans, clinic notes and operation notes were reviewed. A musculoskeletal MRI radiologist blinded to the study reported the incidence of medial and lateral femoral and tibal bone bruises. All images were performed on the same unit.
A total of 73 patients met the inclusion criteria – 28 males and 45 females
- MRI scan performed more than 6 weeks after the initial injury
- Associated posterior collateral ligament injury
- Associated posteriolateral corner injury
- Previous meniscal, chondral or ACL injury
- Over 20 years old
- Medial meniscal tears were noted in 46.6% of the patients, while lateral meniscal tears were noted in 39.7%.
- There were 34 medial meniscal tears (12 in male patients and 22 in female)
- There were 29 lateral meniscal tears (12 in male patients and 17 in females)
- Lateral plateau contusions were more common than medial plateau contusions (91.8% versus 61.6%)
- Locations for contusions and meniscal tears was very similar between male and female patients, except that lateral femoral contusions were more common in females than males – however this was not statistically significant.
Their results found that there was no significant difference noted between sexes for location of tibial contusions, femoral contusions of meniscal tears. In both men and women, the most common tibial contusion pattern was to have both medial and lateral tibial contusions.
The results suggest that a valgus load is not a more prominent mechanism in non-contact ACL injuries and in particular not a more popular mechanism in female athletes. Due to the location of the bruising (mostly over the lateral plateau contusions rather than medial plateau contusions), the authors hypothesise that the lateral plateau may translate further anteriorly than the medial plateau because of the difference in slope and tibial internal rotation.
- Small sample/participant group
- There were more woman than men in the group (45 versus 28)
- The study group is specific to a younger population (< 20 years old) and therefore may not be representative of injury patterns in older adult knees
Real world Implications
The results mean that when looking at ACL prevention, there should be no variation in treatment in men versus women. When treating ACL rupture patients physiotherapists should be mindful of the likelihood of bone bruising (especially laterally) and also a potential for meniscal damage. This bone bruising may have implications on when impact (jumping/hopping and running) activities should be undertaken. The bone bruising may relate to the condition of the chondral cartilage on the surface of the bone. Often the bone bruising will take a significant amount of time to settle – sometimes as long as 18 months. This doees not mean running and jumping need be avoided, it just means the areas of bone bruising and the extent need to be considered when putting together the rehabilitation program. A discussion between your physio and your surgeon will help determine the best way forward.
It is likely that 3-dimensional modelling of the contusion sites may be helpful in re-creating the mechanism of ACL injuries in both male and female patients. Of course further studies with larger sample groups and a variety of ages would provide more significant and relevant results.
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