Abstract
Background
Now a day's many surgeries are done around the head and neck of femur like femoral head resurfacing arthroplasty for managing advanced hip-joint degeneration. Thus, it is vital for an orthopaedic surgeon to exactly understand the vascular supply of the neck of femur. The knowledge of distribution of foramina and their relation to the retinacula of Weitbrecht will help orthopaedic surgeons to choose their management technique for various injuries. So, this study was undertaken to study the number, size and distribution of nutrient foramina in all the surfaces of neck of femur and their relations to the retinacula of Weitbrecht.
Materials and method
Study was conducted on 200 adult dry femora. The retinacula of Weitbrecht are first defined later the subcapital, transcervical and basicervical regions of the femoral neck are marked. The number of foramina, size and their distribution in relations to the retinacula of Weitbrecht were observed. Later the results were analyzed statistically.
Results
40.01% of foramina were observed in the subcapital region, 31.74% in basicervical and 28.24% were noted in transcervical region. The nutrient foraminal density was significantly higher in the upper retinacula (57.03%), followed by anterior retinacula (27.3%) and least in the region of inferior retinacula (15.66%). It was observed that most foramina were less than 1 mm diameter followed by 1–2 mm diameter foramina.
Conclusion
This knowledge of foraminal distribution in femoral neck will be helpful in surgeries involving the hip joint and femoral head & neck fractures.
Keywords: Nutrient foramina, Femur neck, Femur head, Orthopaedic surgeons, Avascular necrosis
Highlights
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The distribution of 9171 nutrient foramina was studied in 200 femoral neck in relation to the retinacula of Weitbrecht .
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It was observed that superior surface had maximum foramina followed by the posterior, anterior and inferior surface .
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The foraminal density was significantly higher in the region of upper retinacula (57.03%).
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Most foramina were less than 1 mm in diameter and >2 mm diameter foramina were few and found more in basicervical region.
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This knowledge of foraminal distribution will help the surgeon to predict avascular necrosis and plan surgical procedures.
1. Introduction
Now a days orthopaedic surgeons are trying various procedures to preserve the joints like femoral head resurfacing arthroplasty for managing advanced hip-joint degeneration. In such cases they should be aware of the detailed vascular anatomy of the femoral head and neck.1
The femoral head is supplied on its superolateral aspect by posterior retinacular branches of medial circumflex femoral artery and anteroinferior aspect by lateral circumflex femoral artery, branches of profunda femoris artery, which is the largest branch of femoral artery.2,3
The anatomy of the retinacula of Weitbrecht and its relation to the nutrient foramina in the region is of profound significance as the retinacula act as bridges for vessels supplying the head of femur.4,5 There are 3 retinacula of Weitbrecht anterior, upper and lower in and around which many nutrient foramina are located. Studies have shown that arthrotomy done on the anterior surface of the femoral neck is safe and it will not compromise vascularization of the femoral head. On the other hand if it is done from the upper surface of the femoral neck it may injure the lateral retinaculum and the arteries located there.5
Fracture of neck of femur is one of the most common complications following road traffic accidents. The incidence increases in old age due to osteoporosis were subcapital, transcervical and basicervical fractures can occur even after trivial injuries. Both the medial and lateral circumflex artery give branches which pass through the retinacula of Weitbrecht and supply the femoral head and neck.5 After any injury to femoral neck it is very important to determine the degree of damage that has happened to the blood supply to the femoral head and retain it as much as possible during management.6
A literature review reveals that most studies on femora focus on nutrient foramina distribution in its diaphysis.7,8 There are very few studies on distribution of nutrient foramina in neck of femur.9,10 Moreover, very few of them have studied the relationship of the foramina to the retinacula of Weitbrecht.6
Thus, detailed vascular anatomy of the femoral head and neck should be known to the orthopaedic surgeon before planning any surgical intervention after assessing the site of fracture, the surfaces involved and the extent of damage to the retinacula. If detailed vascular anatomy is not known it can lead to avascular necrosis of femur head or even high mortality rate. So, the aim of our study is to understand the size and distribution of nutrient foramina through which blood vessels enters in all the surfaces of neck of femur and their relation to the retinacula of Weitbrecht.
2. Material and methods
An observation study was done on 200 adult dry femora which were available in the department of Anatomy. Sex and age of the bones was not known.
2.1. Inclusion criteria
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1.
Only adult femora are selected based on epiphyseal growth plate of the femoral head closure.
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Only femora with intact femoral neck are selected.
2.2. Exclusion criteria
The femora with broken upper end and morphological deformities are excluded like presence of osteophytes etc.
The retinacula of Weitbrecht are first defined and the femoral surfaces related to the retinacula are marked as shown in Fig. 1A, B and 1C. The information regarding the position of the anterior, upper, and lower retinacula of Weitbrecht is obtained by examining the retinacula in the formalin fixed specimens.
Fig. 1.
1A, 1B and 1C showing surfaces of neck of femur and their relationship to the retinacula. The anterior (1), upper (2) & lower (3) retinacula of Weitbrecht are shown.
The subcapital, transcervical and basicervical regions of the femoral neck are marked as described by Lavigne et al., in 2005.1
2.3. Subcapital region
The area between a line drawn along the margin of articular surface of femoral head (LINE 1) and a parallel line 1 cm distal to this line (LINE 2) represents the subcapital region of femoral neck as depicted in Fig. 2.
Fig. 2.
Showing the subcapital, basicervical and transcervical region of neck of femur.
2.4. Basicervical region
The basicervical region is marked by first drawing a line at the junction between the femoral neck and the lesser and greater trochanters. Then two parallel lines are drawn 0.5 cm proximal and distal to this line. The area between these two parallel lines is the basicervical region as depicted in Fig. 2.
2.5. Transcervical region
The area between the subcapital region and the basicervical region is marked as the transcervical region as depicted in Fig. 2.
Firstly the foramina are counted in the anterior, posterior, superior and inferior areas of the subcapital, basicervical and the transcervical regions of femur.
The distribution of foramina in relation to the retinacula of Weitbrecht was also noted down.
The size of the foramina is measured using Kirschner wires (K-wires) of 1.0 mm dia. × 150 mm and 2.0 mm dia. × 150 mm. The minimum diameter of each foramen is noted.
The foramina are counted by two observers and if there is a difference in the result the procedure is repeated.
The data was analyzed using SPSS (Statistical Package for Social Sciences, version 20.0, SPSS Inc, Chicago, IL, USA) software.
3. Results
The number of nutrient foramina in subcapital, transcervical and basicervical regions of femoral neck is tabulated in Table 1.
Table 1.
Depicts the nutrient foraminal distribution in femoral neck.
| Number of bones (n = 200), Total Number of nutrient foramina (9171) | |||||
|---|---|---|---|---|---|
| Region | Anterior | Posterior | Superior | Inferior | Total |
| Subcapital | 550(15%) | 1138(31%) | 1908(52%) | 74 (2%) | 3670 (40.01%) |
| Transcervical | 337(13%) | 647(25%) | 1502(58%) | 104(4%) | 2590 (28.24%) |
| Basicervical | 640(22%) | 873(30%) | 1310(45%) | 88 (3%) | 2911(31.74%) |
9171 foramina were studied in 200 femora. 40.01% of foramina were observed in the subcapital region, 31.74% in basicervical and 28.24% were noted in transcervical region. In all the three regions majority of the foramina were observed in the superior surface followed by posterior surface. The anterior surface had significantly lesser foramina and the inferior surface showed least foraminal density.
The distribution of foramina in relation to the retinacula of Weitbrecht is shown in Table 2. 6833 out of 9171 (74.51%) foramina were observed in this region (retinacula of Weitbrecht). The nutrient foraminal density was significantly higher in the upper retinacula (57.03%), followed by anterior retinacula (27.3%) and least in the region of inferior retinacula (15.66%).
Table 2.
Depicts the distribution of foramina in relation to the retinacula of Weitbrecht.
| Number of bones (n = 200) Retinacula of Weitbrecht | Total Number of nutrient foramina (6833) (74.51%) Number of foramina |
|---|---|
| Anterior | 1866 (27.3%) |
| Upper | 3897(57.03%) |
| Lower | 1070(15.66%) |
The size of nutrient foramina in subcapital, transcervical and basicervical regions is shown in Table 3. It was observed that most foramina were less than 1 mm diameter followed by 1–2 mm diameter foramina. Foramina >2 mm were fewer in number.
Table 3.
Depicts the size of nutrient foramina in subcapital, transcervical and basicervical regions.
| Number of bones (n = 200), Total Number of nutrient foramina (9171) Size of foramen |
|||
|---|---|---|---|
| <1 mm | 1–2 mm | >2 mm | |
| Subcapital | 1600 (43.59%) | 1578 (42.99%) | 492 (13.4%) |
| Transcervical | 1306 (50.42%) | 978 (37.76%) | 306 (11.8%) |
| Basicervical | 1156(39.71%) | 902 (30.98%) | 853 (29.3%) |
It is observed that in all the three regions majority of the foramina are less than 1 mm. Foramina >2 mm are more significantly observed in basicervical region.
4. Discussion
The retinacula act as bridges for vessels that supply the femoral head, a thorough knowledge of the distribution of nutrient foramina and their relation to the retinacula is of profound significance for the orthopaedic surgeon while doing fixation and arthroplasty for the management of fractures of head and neck region of femur.5
We observed that nutrient foraminal density was maximum in the region covered by the retinacula of Weitbrecht suggesting the importance of these retinacula in maintaining vascularity of hip joint and in the pathology of avascular necrosis of head of femur. Disruption or injury of these retinacular branches to the femoral head due to fracture displacement or while doing surgeries can lead to the development of osteonecrosis.6 So knowledge about nutrient foramina and their relation to retinacula of Weitbrecht is clinically very important for the orthopaedic surgeons.
Mei et al., in 2015 involving 76 femora studied 2417 nutrient foramina in relation to the femoral neck and reported that foraminal density was maximum in the superior surface and least in inferior surface. Similar observation is made in our study as well.6 In a study by Dy CJ et al., in 2012 in 16 cadaveric femora 41.8%of the foramina were located in the anterosuperior quadrant.11 In our study we observed more foramina in posterosuperior quadrant. This might be because they have conducted the study in cadavers and in CT scan images. A study by Lavigne et al., in 2005 concluded that most foramina were located in the anterosuperior and posterosuperior areas of neck of femur.1 P Rego et al., in 2017 injected gadolinium into deep branch of medial circumflex femoral artery in 16 fresh cadaveric specimens and conducted an arterial study of femoral neck under MRI. The study observed that most foramina were located from 10 to 12 O'clock position with a mean of 4.5.12 Chung in 1976 conducted a perfusion study of femoral head and neck involving 150 autopsy specimens with age ranging from twenty-six weeks foetus to fourteen years. It was observed that the arteries were scarce on the anterior and medial aspect of femur neck in three to ten-year-old specimens suggesting their possible role in cause of Perthes disease.13 Scarcity of foramina density in the anterior and medial aspect of neck of femur was also observed by Ogden JA in 1974 who attributed vascular regression to growth of femoral neck.14 Sevitt and Thompson in 196510 and Howe et al., in 195015 also observed that the nutrient foramina were scarce in the anterior and medial aspect of neck of femur similar to our study. These results showed that if the orthopaedic surgeon wants to manage the femoral neck fracture the safer area is the anteromedial quadrant as fewer nutrient foramina are located in this area.
Foraminal size >2 mm was more often seen in basicervical region in our study and a similar observation is made by Mei et al., in 2015.6 In both the studies it was observed that most of the foramina are less than 1 mm diameter or 1–2 mm diameter. Tucker in 1949 observed that in adults the retinacular arteries have diameters ranging from 0.10 to 1.55 mm. The posterolateral retinacular vessels were observed to have a mean diameter of 0.84 mm.16 As the basicervical region receives good blood supply as compared to other areas. So, surgeon should take care and be careful while doing surgeries in this area.
In this study nutrient foraminal density was significantly higher in the upper retinacula (57.03%), followed by anterior retinacula (27.3%) and least in the region of inferior retinacula (15.66%). Mei et al., in 2015 also observed high nutrient foraminal density in upper retinacula.6 The results to this will help the surgeons to follow the retinacula while doing the surgeries to prevent damage to blood vessels.
Reaming for resurfacing arthroplasty can cause an average loss of 28% of nutrient foramina and predispose to osteonecrosis of the femoral head.11 The femoral neck has very few vessels that manage to reach the femoral head and hence it was very essential to preserve these foramina in any intracapsular procedure involving hip joint and arthroplasty.1 LE Lazaro et al., in 2013 showed that in the standard posterior approach the inferior retinacular artery and ascending branch of medial circumflex femoral artery were damaged constantly and hence this approach needs to be abandoned as it causes gross vascular compromise to the femoral head and neck. Moreover, in this approach several foramina are damaged as foraminal density is high in posterior and superior surfaces. The modified posterior approach however, most often damaged the ascending branch of medial circumflex femoral artery but rarely damaged the inferior retinacular artery and hence produced lesser vascular compromise but stills needs modification. The best approach observed was trochanteric flip osteotomy which maintained the perfusion of femoral head in 96% specimens and head-neck junction in 98% specimens.17 The scarcity of nutrient foramina in the anterior and inferior surfaces of femoral neck observed in our study was also observed by other authors also.6,10,14,15
Capsulotomy in femoral neck fractures remains a debatable topic. There are both animal and clinical studies concerning capsulotomy. Animal studies showed that raised hip intracapsular pressure results in a tamponade effect and decreases the blood flow to the femoral head.7 Clinical studies shows that if we decompress the intracapsular hematoma via capsulotomy it reduces the intracapsular pressures which increases the blood flow to the femoral head and may reduce femoral head ischemia.18 All vessels which supply the femoral head they are intracapsular so while doing capsulotomy also detailed knowledge about the vascular anatomy of head should be known.
After displaced fracture of neck there are chances of avascular necrosis of head of femur. There are factors which determine the prognosis of patients which include age, degree of fracture displacement, and state of fracture diaplasis.7 So, it is vital to determine the grade of damage to the blood supply to the femoral head after femoral neck fracture and preserve as much of the remaining blood supply to the femoral head as possible during management. This knowledge of foraminal distribution and vascular anatomy of the femoral head and neck will help the orthopaedic surgeon to plan surgical procedures appropriately.
The limitations of the study is no age, gender of bones were known as these are dry bones stored in the department of anatomy. Side of the bones was not studied. Further studies can include that in their studies.
5. Conclusion
A knowledge of foraminal distribution in femoral neck has immense clinical implications in surgeries involving the hip joint and femoral head & neck fractures. In our study majority of the foramina were observed in the superior surface followed by posterior surface. The anterior surface had significantly lesser foramina and the inferior surface showed least foraminal density. 74.51% of foramina were observed in the region of retinacula of Weitbrecht suggesting the importance of these retinacula in maintaining vascularity of hip joint and in the pathology of avascular necrosis of head of femur. The foraminal density was significantly higher in the region of upper retinacula (57.03%), followed by anterior retinacula (27.3%) and least in the region of inferior retinacula (15.66%). Most foramina were less than 1 mm in diameter and >2 mm diameter foramina were few and found more in basicervical region. This knowledge of foraminal distribution will help the surgeon to plan surgical procedures appropriately.
Institutional review board approval or patient consent
Not required as these bones were taken out previously from the donated bodies many years ago so ethical approval is not required and once people have donated their bodies for research and academic purpose consent is implied that we can use that for research.
Author's contribution
Venkatesh Kamath- Conceptualization; Data curation; Formal analysis; Funding acquisition; Investigation; Methodology; Project administration; Resources; Software, Visualization; Roles/Writing - original draft; Chandni Gupta- Supervision; Validation; Writing - review & editing.
Declaration of competing interest
The Authors declares that there is no conflict of interest.
Acknowledgement Section
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
References
- 1.Lavigne M., Kalhor M., Beck M., Ganz R., Leunig M. Distribution of vascular foramina around the femoral head and neck junction: relevance for conservative intracapsular procedures of the hip. Orthop Clin N Am. 2005;36(2):171–176. doi: 10.1016/j.ocl.2005.02.002. [DOI] [PubMed] [Google Scholar]
- 2.Vishram singh. Textbook of Anatomy. Abdomen and Lower Limb. Volume II. third ed. Elsevier. (Chapter 24), pg 347.
- 3.Trueta J., Harrison M.H. The normal vascular anatomy of the femoral head in adult man. J Bone Joint Surg Br. 1953;35B(3):442–461. doi: 10.1302/0301-620x.35b3.442. [DOI] [PubMed] [Google Scholar]
- 4.Arnoldi C.C., Lemperg R.K. Fracture of the femoral neck. II. Relative importance of primary vascular damage and surgical procedure for the development of necrosis of the femoral head. Clin Orthop Relat Res. 1977;129:217–222. doi: 10.1097/00003086-197711000-00029. [DOI] [PubMed] [Google Scholar]
- 5.Gojda J., Bartoníček J. The retinacula of Weitbrecht in the adult hip. Surg Radiol Anat. 2012;34(1):31–38. doi: 10.1007/s00276-011-0829-3. [DOI] [PubMed] [Google Scholar]
- 6.Mei J., Ni M., Wang G., et al. Number and distribution of nutrient foramina within the femoral neck and their relationship to the retinacula of Weitbrecht: an anatomical study. Anat Sci Int. 2017;92(1):91–97. doi: 10.1007/s12565-015-0319-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Barnes R., Brown J.T., Garden R.S., Nicoll E.A. Subcapital fractures of the femur. A prospective review. J Bone Joint Surg Br. 1976;58(1):2–24. doi: 10.1302/0301-620x.58b1.1270491. [DOI] [PubMed] [Google Scholar]
- 8.Santolini E., Goumenos S.D., Giannoudi M., Sanguineti F., Stella M., Giannoudis P.V. Femoral and tibial blood supply: a trigger for non-union? Injury. 2014;45(11):1665–1673. doi: 10.1016/j.injury.2014.09.006. [DOI] [PubMed] [Google Scholar]
- 9.Imre N., Battal B., Acikel C.H., Akgun V., Comert A., Yazar F. The demonstration of the number, course, and the location of nutrient artery canals of the femur by multidetector computed tomography. Surg Radiol Anat. 2012;34(5):427–432. doi: 10.1007/s00276-011-0930-7. [DOI] [PubMed] [Google Scholar]
- 10.Sevitt S., Thompson R.G. The distribution and anastomoses of arteries supplying the head and neck of the femur. J Bone Joint Surg Br. 1965;47:560–573. doi: 10.1302/0301-620x.47b3.560. [DOI] [PubMed] [Google Scholar]
- 11.Dy C.J., Thompson M.T., Usrey M.M., Noble P.C. The distribution of vascular foramina at the femoral head/neck junction: implications for resurfacing arthroplasty. J Arthroplasty. 2012;27(9):1669–1675. doi: 10.1016/j.arth.2012.02.029. [DOI] [PubMed] [Google Scholar]
- 12.Rego P., Mascarenhas V., Collado D., Coelho A., Barbosa L., Ganz R. Arterial topographic anatomy near the femoral head-neck perforation with surgical relevance. J. Bone Joint Surg. Am. 2017;99(14):1213–1221. doi: 10.2106/jbjs.16.01386. 19. [DOI] [PubMed] [Google Scholar]
- 13.Chung S.M. The arterial supply of the developing proximal end of the human femur. J. Bone Joint Surg. Am. 1976;58(7):961–970. doi: 10.2106/00004623-197658070-00011. [DOI] [PubMed] [Google Scholar]
- 14.Ogden J.A. Changing patterns of proximal femoral vascularity. J. Bone Joint Surg. Am. 1974;56(5):941–950. doi: 10.2106/00004623-197456050-00007. [DOI] [PubMed] [Google Scholar]
- 15.Howe W.W., Jr., Lacey T., Schwartz R.P. A study of the gross anatomy of the arteries supplying the proximal portion of the femur and the acetabulum. J. Bone Joint Surg. Am. 1950;32A(4):856–866. doi: 10.2106/00004623-195032040-00015. [DOI] [PubMed] [Google Scholar]
- 16.Tucker F.R. Arterial supply to the femoral head and its clinical importance. J Bone Joint Surg Br. 1949;31B(1):82–93. doi: 10.1302/0301-620x.31b1.82. [DOI] [PubMed] [Google Scholar]
- 17.Lazaro L.E., Sculco P.K., Pardee N.C., et al. Assessment of femoral head and head-neck junction perfusion following surgical hip dislocation using gadolinium-enhanced magnetic resonance imaging: a cadaveric study. J. Bone Joint Surg. Am. 2013;95(23):e1821–e1828. doi: 10.2106/jbjs.l.01185. 4. [DOI] [PubMed] [Google Scholar]
- 18.Bonnaire F., Schaefer D.J., Kuner E.H. Hemarthrosis and hip joint pressure in femoral neck fractures. Clin Orthop Relat Res. 1998;353:148–155. doi: 10.1097/00003086-199808000-00017. [DOI] [PubMed] [Google Scholar]