The effect oftibial torsion and femoral anteversion on acces of anterior cruciate ligament and meniscus cartilage tears

ABSTRACT

Aim: The aims of this study were to evaluate of the effect of axial deformity such as, tibial torsion and femoral anteversion on access of Anterior Cruciate ligament (ACL) and meniscus cartilage tears in the elite athletes.

Methods: Three 11-person groups with damaged ACL ligament, damaged meniscus, and with no damages participated in this research. Athletes with meniscus and ACL tears are selected randomly by referring to medical records and unaffected group selected by randomly from basketball, football and handball fields. To evaluate femoral and leg’s torsion angles (tibial torsion and thigh anteversion), CT scan instrument was used.

Results: In this research attended by 33 male athletes with means of age 24.3±5.2 yr, of height 1.795±8.4 m, and of weight 76.5±12.5 Kg, investigation showed that none under – study variables, including abnormalities of tibial torsion and thigh anteversion, were significantly different among studied groups.

Conclusion: Despite that many researchers have been considered torsional factors of lower extremity as risk factor of the ACL ligament ruptures, but the results of this study showed that factors of tibial – and/or thigh – direction torsion cannot be considered as risk factors for meniscus and ACL ante – cruciate ligament damages.

Introduction

Knee joint damages account for 50% of motor joints damages. Of all kinds of athlete’s knee joint damages the meniscus damages have the highest rate (21.4%), and it is well-known that the meniscus provides vital load bearing and shock-absorbing functions that are important for the integrity and preservation of the articular cartilage in the knee joint Rubman & et al (1998). The anterior cruciate ligament (ACL) is one of the four main ligaments which stabilizes the knee joint and is often injured in sports such as skiing, basketball and football Azangwe & ea al (2002). In addition, ACL ligament tears account for 50% of total knee ligament damages which have attracted specialists’ attention Popov (1999), Ahanjan (2002) and Christine (1999).

Different factors such as tibial torsion (TT) and femoral neck anteversion (FNA) have been studied as risk factors facilitating the occurrence of mentioned injuries, but the results are still ambiguous. Therefore, we have investigated the role of femoral and leg torsional abnormalities in causing these injuries occurring in that present study: 1) TT is tibia turning around longitudinal axis which results in changes in direction of motor plates of primary – and end – joints [4, 5]; 2) FNA is described as normal torsion or torsion of femur that normally is 10-15 degrees Tayton (2007). In a study done on 50 healthy men, Seber (2000) reported averages of 29.1o and 30.9o for normal TT in right and left leg, respectively. Seber has reported averages of 15.6o and 15.8o for normal FNA in right and left legs, repeatedly seber & hazer (2000). On the other hand many studies have been performed on the relation between torsional abnormalities of lower leg and prevalence of ACL ligament tears, but all of them were somewhat uncertain, and didn’t consider objective cases. Meyer, for example, has reported tibial external torsion as facilitating risk factor in their studies of ACL damage Jay& et al (2004). 

Quoted from Hootchinson (1995), tibial external torsion and femoral neck anteversion can be noted as risk factors facilitating affliction of ACL injury Cibulka (2004). No study has been done in the field of the effect of such abnormalities on the occurrence of meniscus tears. But regarding an induced acceleration analysis model by Schwartz (2002) about effect of tibial torsion on the ability of the soleus to support and propel the body during gait. His results showed that excess tibial torsion shifts the induced knee joint accelerations toward flexion, valgus and external rotation. On the other hand, Hicks (2006) showed that excess knee flexion caused a higher stress on meniscus Hicks & et al (2007), gaio (2003). According to the subjects mentioned, and that no study exactly investigated this problem. So this study that is done in Iran tries to clarify some ambiguous existing in this field and to investigate it objectively.

Materials and Methods

The aim of present analytical (case-control)research is to study the role of torsional abnormalities in the occurrence of ACL ligament and meniscus cartilage tears in professional athletes from different sport courses. Unlike earlier studies, which addressed the problem theoretically and stated torsional abnormalities of lower limb direction as the possible cause of ACL injury Timothy & et al (2006); this study has investigated objective cases. Many studies, also, used goniometry techniques for measuring angles which are not of high accuracy, while this study investigates objective cases using precise CT instrument which reveals this study’s superiority to other ones Alvik (1962) , Ruwe & et al (1992).Statistical population of the present study was made up of all athletes having ACL ligament and meniscus cartilage tears. Statistical sample of this research consisted of 22 affected athletes selected randomly by referring to medical records kept in Imam Reza Hospital Center. And 11 unaffected athletes were selected randomly from basketball, football and handball fields.Having been selected, subjects were divided into 2 groups: test group (having ACL ligament and meniscus tears) and control group (unaffected) that were homogenous in terms of sports background, height, weight, and activity level (TableI).Then the best desired cut was printed by CT machine (Model Spiral) and the subjects’ torsional angles of tibia and femoral neck anteversion were drawn. This study was approved by Moral Committee of Kermanshah Razi University.

Some lines were drawn considering the angle between perpendiculars of these 2 lines as the angle of femoral anteversion in order to evaluate the degree of femoral anteversion from the center of femoral head and neck and posterior margin of femur inferior end – head(Rittmeister & et al2006) ( fi gure1).To evaluate tibial torsion angle from the margin of primary head and tibial – fibular center of end head of tibia, some lines were drawn and the angle femoral by their perpendiculars showed the angle of tibial torsion (Liu & et al 2005)( fi gure2).Statistical analysis was performed in 2 phases. Initially, data was analyzed by descriptive method, and, then, by one way ANOVA method and Toukey’s Post Hoc test. Obtained information was entered in SPSS (version 15) software. Then Statistical one way ANOVA method was employed to compare 3 groups measured variables means, with significance level being 0.05.

Results

Results of the study showed no significant difference in tibial torsion degree between unaffected persons and those having meniscus damage.  Also the comparison of femoral anteversion degrees in unaffected people and those with damaged meniscus showed no significant difference. Moreover, values of tibial torsion and of femoral anteversion in healthy people were not significantly different from those of individuals having damaged ACL (TableII). Also Post Hoc tukey’s test showed no significant difference in tibial torsion degree and femoral anteversion degrees between three groups. The other result of this study shows that 45.5% of participants have injury in left leg and 21.2% of them have right leg injured, so that among those having meniscus damage, 72.2% of participants have injury in left leg and 27.3% have right, and among those having ACL damage 63.6% of participants have injury in left leg and 36.4% of them have right leg injured, but there were no significant differences between menisci and ACL groups (P<0.001) (TableIII).

Discussion

Torsional abnormalities along lower limb have been reported as possible risk factors facilitating ACL ligament injury. Although, in theory, torsional abnormalities are related to the prevalence of ACL ligament tears, no studies have been performed in relation to the role of such abnormalities in the occurrence of meniscus tears. Comparing the degrees of tibial torsion and femoral anteversion in unaffected athletes and those with ACL and meniscus tears, the present research attempts to study more possible role of and being greater of such torsional abnormalities in occurring ACL and meniscus damages in the case of observing a significant difference in the degrees of tibial torsion and anteversion between affected and unaffected groups.
Testing this hypothesis showed that there was no significant difference in the degrees of tibial torsion and anteversion between the group with ACL ligament and meniscus cartilage tears and unaffected group.

Studying the effect of torsion on complete tear of rabbits ACL ligament, Azango (2002) noted that torsion has an effect on both structure and mechanics of ACL ligament. In a book titled Sports Exercises – Sports Medicine, Starkey has defined additional stresses of tibial torsion as the cause of 2 ACL and MCL ligament tear (Starkey & Johnson 2006). Miesser, Hootchinson et al. have noted femoral anteversion as one of factors facilitating the occurrence of ACL ligament tear (Silvers & Mandelbaum 2002). For mechanism of ACL ligament tear, Vezzoni (2005) believes that over – extension of knee and tibial torsion cause this ligament to be torn completely while femoral anteversion causes knee to rotate inward and the very background stress results in ligament tear( & et al 2005). Researches by Mouchla et al. (2006) have shown that torsional deformities of proximal tibia head and/or of femur end head can damage ligament at synovial level, increasing joint clipping forces as the result of thickening cartilage layers, which is an important factor facilitating ACL ligament injury (Moschella & et al 2006, Turner & semillie 1981).

Although above findings are not in agreement with those of present research, considered subjects were more based on theories and assumptions and none of them has been studied objectively. But another researcher, named Harrner (1994), has evaluated the degree of femoral and calf torsional abnormalities in 2 groups of unaffected athletes and those having ACL ligament tear objectively and observed that there was no significant deference in degree of femoral anteversion between damaged and unaffected groups and its degree between damaged and unaffected legs. In addition, the degree of tibial torsion in healthy group was not significantly different from the affected group(Harner & et al 1994). One reason for the possibility of existence of a relation between meniscus injury and tibial torsional abnormalities is a report suggesting that internal/external meniscus bear 50% – 70% of body weight when knee is extended. While the knee is flexed the figure reaches 85% – 95%.  So it seems that the more the knee is flexed, the higher the stress on meniscus becomes. Hickes’s findings show that extra tibial torsion results in more flexion at knees area; therefore, the tolerance of and the weight transfer on meniscus as well as the stress posed on them increase, rising the probability of meniscus injury(Prasad & et al  1999).

In this study, most subjects with menisci tear had internal menisci tear, and nearly all of them had legs turned outward. This observation is partly in agreement with the results of Burg’s research who believes that when foot and calf are in the position of outward torsion with respect to thigh, internal meniscus is susceptible, and in the position of inward torsion, external menisci is susceptible(Berg 1997) . Although the degree of torsion in people having menisci tear is higher than that of unaffected persons, this difference was statistically not significant. Although the degree of tibial torsion in group with ACL tear was. On average the reported normal range of 30o, it was not different from the value of unaffected group. Low number of subjects and type of athletes selected as healthy subjects can be considered of probable factors affecting the results of the research. Any (2006), for example, showed that soccer players potentially have external tibial torsion higher than non- athletes individuals as well as athletes from other sports courses. Therefore, it is expected that more exact results can be obtained by selecting athletes from 2 particular sports groups (Yaniv& et al 2005).

Conclusion

The results of present study show that, in a chosen significance level, tibial torsions and femoral anteversion in the group of participants with ACL and menisci damages were not significantly different from healthy group. So this factor cannot be considered as a factor facilitating the occurrence of mentioned damages in under – study subjects. On the other hand, since the researcher had limitations related to the number of subjects and to the selection of their sports courses, further research is needed in this field?

Table 1. The effect oftibial torsion and femoral anteversion on acces of anterior cruciate ligament and meniscus cartilage tears

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Table II. ANOVA result, comparison mean of tibial torsion and femoral anteversion in 3 groups

Mean±SD

Table III. Frequency of leg injured