|Year : 2014 | Volume
| Issue : 2 | Page : 64-68
Relationship of distal femoral morphometrics with anterior cruciate ligament injury using MRI
Sameh A Khodair1, Usama E Ghieda1, Amr S Elsayed2
1 Radiology Department, Faculty of Medicine, Tanta University, Tanta, Egypt
2 Orthopedic Department, Faculty of Medicine, Minoufia University, Minoufia, Egypt
|Date of Submission||26-Mar-2014|
|Date of Acceptance||17-Apr-2014|
|Date of Web Publication||31-Jul-2014|
Sameh A Khodair
Radiology Department, Faculty of Medicine, Tanta University, Tanta, 32631
The aim of the study was to compare the distal femoral morphology in anterior cruciate ligament (ACL) noninjured and injured patients and to explore differences between men and women.
Patients and methods
Retrospective study of MRI measurements of the distal femur of 159 patients was conducted; notch width (NW), bicondylar width (BCW), and notch index (NI) were measured in 72 patients with ACL injury and in 87 patients without ACL injury. All patients underwent knee arthroscopy. The measured values in both ACL-injured and non-ACL-injured male and female individuals were analyzed; P value less than 0.05 was considered to be statistically significant.
There were significant differences in NW and BCW between male and female individuals with non-ACL injury (P = 0.000), whereas no statistically significant difference was noted regarding NI (P = 0.789). There was statistically significant difference in the male group with ACL injury regarding NW and NI (P = 0.000), with no significant statistical difference regarding BCW. In the female group, there were significant differences (P = 0.000) in the bone morphology between ACL-injured and non-ACL-injured individuals, including NW, BCW, and NI.
There was difference between male and female distal femur morphologies. In both sexes, patients with small NI and NW are at high risk for ACL injuries.
Keywords: anterior cruciate ligament injury, knee injury, morphology, MRI
|How to cite this article:|
Khodair SA, Ghieda UE, Elsayed AS. Relationship of distal femoral morphometrics with anterior cruciate ligament injury using MRI. Tanta Med J 2014;42:64-8
|How to cite this URL:|
Khodair SA, Ghieda UE, Elsayed AS. Relationship of distal femoral morphometrics with anterior cruciate ligament injury using MRI. Tanta Med J [serial online] 2014 [cited 2017 Aug 23];42:64-8. Available from: http://www.tdj.eg.net/text.asp?2014/42/2/64/137806
| Introduction|| |
The anterior cruciate ligament (ACL) is considered to be the most commonly injured ligament of the knee, as ACL injury represents 50% of all knee injuries .
An identification of the risk factors for ACL injury may help reduce the rate of these injuries. One of the anatomical factors that have been subjected to considerable interest is the morphology of the femoral intercondylar notch and the relationship between notch stenosis and ACL disruption .
Palmer  in 1938 was the first investigator to suggest that a narrow intercondylar notch may place the ACL at risk for injury, as the ligament is stretched over the medial edge of the lateral femoral condyle. Since that time, several studies have evaluated the role of narrow intercondylar notch as a risk factor for ACL injury. The majority of studies suggested that notch stenosis is associated with a higher risk of ACL injuries [4-9]; however, others did not find significant differences between notch measurements of uninjured individuals and those with ACL tears [10-12]. Thus, it is necessary to show accurate data to resolve these controversial debates.
Soryal et al.  described a method of measurement of intercondylar notch width (NW) and the notch width index (NWI) on plain tunnel view radiographs. Similar measurements for describing the dimensions of intercondylar notch have been performed using computed tomography and MRI [10,14-17].
| Patients and methods|| |
This study was a retrospective case-control study. After receiving our institutional approval, we reviewed MRI scans of patients with ACL injury verified by arthroscopy between June 2011 and July 2013, whereas the control group had an MRI for knee problems other than ACL injury, such as meniscal injuries, or for no pathology. Patients with advanced osteoarthritis, older patients above 50 years, and patients with multiple ligamentous injury were excluded.
Following these rules, total of 159 patients MRI were obtained. The ACL-injured group included 72 patients, 34 men (mean age 33.3 years) and 38 women (mean age 32.4 years). The causes of ACL injury were traffic accidents for 70 patients, sport injury for 30 patients, and others for 20 patients. The non-ACL-injured group (the control group) consisted of 87 patients, 40 men (mean age 32.4 years) and 47 women (mean age 31.3 years).
All MRI scans analyzed in this study were performed on a 1.5 T System (Signa Excite; GE Medical Systems, Milwaukee, Wisconsin, USA) using the phased-array knee coil, with the knee in 10° of flexion.
Three experienced radiologists independently reviewed the MRI in random order and in a blinded manner.
The measurements included intercondylar NW, bicondylar width (BCW), and NWI on a computer workstation for accurate assessment. The same STIR coronal image was used in each patient to measure femoral BCW and intercondylar NW. The image chosen for measurements was as close as possible to the midsubstance of the ACL at the point of decussation of the ACL and posterior cruciate ligament (PCL). First, we measured the BCW at the popliteal groove in the lateral condyle of the femur, parallel to the joint line as formed by the distal femoral condyles (line A) [Figure 1]. Thereafter, on the same line, we identified the most interior margins of the femoral condyles at the borders of the intercondylar notch. The distance between the two points represents the intercondylar NW (line B) [Figure 1]. The ratio of the intercondylar NW to the BCW (line B/line A) represents the NWI.
Three experienced radiologists independently performed these measurements in random order and in a blinded manner, and the average of the three measurements was recorded.
|Figure 1: STIR coronal view of knee MRI at an intermediate imaging among the obtained ones where the popliteal grooves are seen and where the indicated morphometric values were measured. Line A is the bicondylar width. Line B is the notch width.|
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The difference in bone morphology (NW, BCW, and NWI) between men and women and the difference between ACL-injured and non-ACL-injured individuals were analyzed using the Mann-Whitney U-test. P values less than 0.05 were considered statistically significant. All statistics were performed using Minitab (ver. 16; Minitab Inc., USA).
| Results|| |
This study was conducted on 159 patients; their ages were 20-43 years (mean age 33.7 ± 5.3 years). There were 74 male patients, 40 patients with non-ACL injury (mean age 32.4 years) and 34 patients with ACL injury (mean age 33.3 years).
There were 85 female patients, 47 patients with non-ACL injury (mean age 31.3 years) and 38 patients with ACL injury (mean age 32.4 years).
Normal populations with non-ACL injury included 87 patients (40 men and 47 women). There was statistical significance between men and women in this group regarding NW and BCW (P = 0.000), whereas there was no statistical significance regarding notch index (NI) (P = 0.078) as shown in [Table 1].
|Table 1 Comparison between non-anterior cruciate ligament-injured men and women|
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Male populations with non-ACL injury included 40 patients, whereas those with ACL injury included 34 patients. There was statistical significance between non-ACL injury and ACL injury in male patients regarding NW and NI (P = 0.000), whereas there was no statistical significance regarding BCW (P = 0.0981) as shown in [Table 2].
|Table 2 Comparison between non-anterior cruciate ligamentinjured and anterior cruciate ligament-injured men|
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Female populations with non-ACL injury included 47 patients, whereas those with ACL injury included 38 patients. There was statistical significance between non-ACL injury and ACL injury in female patients regarding NW and NI (P = 0.000); in addition, there was statistical significance regarding BCW (P = 0.002) as shown in [Table 3] [Figure 2], [Figure 3], [Figure 4].
|Figure 2: Difference between distal femoral morphology between men (a) and women (b) with larger bicondylar width and notch width in men than in women.|
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|Figure 3: Significantly smaller notch width in a male patient with anterior cruciate ligament (ACL) injury (a) than in a male patient with non-ACL injury (b).|
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|Figure 4: Significantly smaller notch width in a female patient with anterior cruciate ligament (ACL) injury (a) than in a female patient with non- ACL injury (b).|
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|Table 3 Comparison between non-anterior cruciate ligamentinjured and anterior cruciate ligament-injured women|
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| Discussion|| |
The high frequency of injury to the lower extremities and, specifically, to the ACL due to participation in sports among young athletes has prompted considerable investigation into the effects of age, sex, body size, flexibility, laxity, muscle strength, previous injuries, rehabilitation programs, and anatomical alignment as risk factors for ACL injury. One of the anatomical factors that is the subject of considerable debate is the morphology of the femoral intercondylar notch and the relationship between NW and disruption of the ACL .
NW affecting ACL injury has been identified in various studies, but the results are still controversial because of the differences in the measurements and patients. Results on NWI, as a risk factor for ACL tear, are also contradictory [2, 6, 11].
The imaging modality used to measure NW has been the topic of considerable debate [7, 10, 14-17]. Plain radiographic measurements of NWI are easy to obtain but may be affected by patient positioning and variability in technique, projection, and magnification . Herzog et al.  demonstrated that MRI measurements of intercondylar NW were more accurate than those made on plain radiographs when compared with direct measurements from cadaveric specimens.
Murshed et al.  and Park et al.  showed that men had much larger size of the distal femur morphology than women, and also Vrooijink et al.  found a significant difference for BCW (P = 0.001) between male and female patients. Stijak et al.  showed that the width of male intercondylar notch was greater than the width of female intercondylar notch, with statistical significance. Other studies reported that men possessed larger volume of condyle than women [7, 9, 23, 24]. This is in agreement with our study in which we found that male knee bony morphology was larger than female morphology regarding BCW and NW.
As far back as 1938, Palmer  recognized the role of a narrow intercondylar notch in ACL injury. Feagin et al.  noted that the width of the intercondylar notch might also impact the success of surgical reconstruction of the ACL. Souryal and Freeman  found a correlation between intercondylar notch stenosis and bilateral injury of the ACL.
Anderson et al. [14,26] analyzed the computed tomography data to compare and study the bony morphology between men and women with ACL injury and non-ACL injury. They concluded that a knee with a small condylar notch might increase the rate of ACL rupture.
Park et al.  found that the average NW values of the male ACL-injured patients were significantly smaller than those of non-ACL-injured patients, whereas NWI was not significantly different between the two groups. In the same comparison in female patients, NW and NWI were significantly smaller in ACL-injured patients than in non-ACL-injured patients. They discovered that the narrow NW could be a risk factor in men and women. In case of narrow NWI, it could be another risk factor in women. In our study, we found that both NW and NWI were significantly smaller in the ACL-injured group that in the non-ACL-injured group in both male and female population.
Lombardo et al.  showed a different result compared with the previous studies. After measuring the NW from notch view radiograph of 615 male basketball players, they concluded that critical notch stenosis between ACL-injured and non-ACL-injured patients had no associations.
Recently, Uhorchak et al.  in an 11-year prospective study among professional male basketball players compared NWI in 14 ACL-injured players with 291 uninjured players. In this radiographic study, they did not show any difference in NWI between groups. Conclusions from this study may be limited, as professional basketball players are exposed to very high ACL demand activities, and NWI cannot be considered the only risk factor in this group of athletes.
The most important finding of this study was that there were differences in bony morphology between ACL-injured and non-ACL-injured patients. These differences in bony morphologic characteristic varied for men and women.
| Conclusion|| |
The study shows the differences in distal femur bone morphology between men and women and significant differences in bony morphology between the ACL-injured and non-ACL-injured groups. In addition, there was one more significant difference at NW and NWI between both ACL-injured and non-ACL-injured men and women. The MRI measurement was proven to be effective, and radiologists need to be more cautious when observing and diagnosing patients with small NW and NWI in MRI, because patients with small NW and NWI tend to have higher possibility of ACL injuries.
| Acknowledgements|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3]