• Users Online: 424
  • Print this page
  • Email this page


 
 
Table of Contents
CASE REPORT
Year : 2022  |  Volume : 71  |  Issue : 2  |  Page : 151-153

Unilateral Absence of Round Ligament of Femur -Cadaveric Case Report


,

Date of Submission22-Dec-2021
Date of Decision25-Feb-2022
Date of Acceptance25-Mar-2022
Date of Web Publication30-Jun-2022

Correspondence Address:
Divya Umamaheswaran
,

Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jasi.jasi_210_21

Rights and Permissions
  Abstract 


Round ligament of femur is a pyramidal structure with apex attached to the fovea of the femoral head and its base blends with the transverse acetabular ligament. It is an intracapsular but extrasynovial structure. It is also called ligamentum teres femoris or foveal ligament. It transmits the acetabular branch of obturator artery and also acts as a secondary stabilizer of the hip joint by supplementing the other ligaments of the hip joint in extreme range of motion. Absence of round ligament of femur is a rare variation which can be unilateral or bilateral and prevalence is 2%–3%. It presents rarely as isolated entity or in association with congenital dysplasia of the hip. This report presents a rare variation of unilateral absence of round ligament of femur with minimal evidence of developmental dysplasia of the hip. During routine dissection of a middle-aged cadaver, on opening the hip joint cavity, the round ligament of femur was absent on the left side whereas, acetabular labrum and femoral head were normal. On the right side, the lower limb was normal in position and round ligament of femur was present in normal length and thickness. Awareness and knowledge of such a rare variation are important for radiologists and orthopedicians for better diagnosis and management of hip-related problems.

Keywords: Acetabular branch of obturator artery, fovea capitis, foveal ligament, hip joint, ligamentum teres femoris, total hip replacement


How to cite this article:
Umamaheswaran D, Chigurupati N, Solomon P, Devi R. Unilateral Absence of Round Ligament of Femur -Cadaveric Case Report. J Anat Soc India 2022;71:151-3

How to cite this URL:
Umamaheswaran D, Chigurupati N, Solomon P, Devi R. Unilateral Absence of Round Ligament of Femur -Cadaveric Case Report. J Anat Soc India [serial online] 2022 [cited 2022 Aug 17];71:151-3. Available from: https://www.jasi.org.in/text.asp?2022/71/2/151/349532




  Introduction Top


Round ligament of femur was initially thought to be a vestigial structure but now its importance and interest have been increasing since it was found to be acting as a secondary stabilizer of the hip joint. With an increase in the use of arthroscopy in surgical management, recent studies have concluded that repairing ligamentum teres will provide more stability to the hip in case of any tears. In this background, knowledge about round ligament of femur is very important.

Round ligament of femur although very small, it is quite strong ligament. It is a pyramidal structure with apex attached to the fovea of the femur head and its base is blending with the transverse acetabular ligament. It is an intracapsular but extrasynovial structure. It is also called ligamentum teres femoris or foveal ligament. Its mean length is 30–35 mm.[1] It transmits the acetabular branch of obturator artery, but now recent studies have proven that it also acts as a secondary stabilizer of the hip joint by supplementing the other ligaments of the hip joint in extreme range of motion.[2],[3],[4],[5],[6]

Absence of round ligament of femur is a very rare variation with the prevalence of 2.8% in Asian population.[7] Absence can be unilateral or bilateral. Unilateral absence is more common when compared with the absence on both sides.[8] Rarely, it will be presented as isolated entity and very often associated with developmental dysplasia of the hip.

Since it is very rare variation, this case reports unilateral absence round ligament of femur with minimal evidence of developmental dysplasia of the hip. To the best of my knowledge, this was the first case report of unilateral absence of round ligament and associated developmental dysplasia of the hip in India. This variation is important for radiologists and surgeons.


  Case Report Top


During routine dissection of the lower limb of an approximately 55-year-old Indian adult male cadaver in the Department of Anatomy, Pondicherry Institute of Medical Sciences. General examination of both limbs showed that the left lower limb was slightly laterally rotated, even though there was no obvious limb length discrepancy or any evidence of previous hip surgeries.

Muscles near both hip joints were dissected out. On opening, the left hip joint by dissecting the iliofemoral ligament, femur head came out immediately without any resistance. Femur head was normal with a complete round contour, smooth surface with normal fovea capitis but the round ligament of femur was absent as shown in [Figure 1]. Acetabular cavity was also smooth without any evidence of attachment of ligament. Acetabular cup and Acetabular labrum appeared normal. Absence of round ligament of femur was confirmed after discussing with orthopedic surgeon.
Figure 1: (a) Left femur head, arrow shows fovea capitis (b) left acetabular cavity with no attachment of any ligament. FC – Fovea capitis

Click here to view


Dissection of the right hip joint was proceeded after dissection of iliofemoral ligament, femoral head was observed to be present inside the acetabular cavity and round ligament of femur was present as shown in [Figure 2]. Because of the presence of the ligament, femoral head did not come out immediately on opening the hip joint. The round ligament of femur was pyramidal in the shape of normal thickness and was well formed. Apex is attached to the fovea capitis and the base was blending with the transverse acetabular ligament. The head of femur was round and normal in contour. Acetabular cavity was normal. Acetabular labrum was normal.
Figure 2: (a) Femur head on both sides, blue arrow showing presence of ligamentum teres, red arrow showing absence of ligamentum teres. (b) Right femur head, arrow shows round ligament of femur. (c) Right acetabular cavity with the attachment of ligamentum teres. LT – ligamentum teres femoris

Click here to view


After disarticulating both lower limbs, diameter and the depth of the acetabular cup of both sides were measured and tabulated in [Table 1]. All the findings in the specimen were photographed and documented.
Table 1: Acetabular cup measurements

Click here to view


The left acetabular cavity was found to be shallower than the right acetabular cavity.


  Discussion Top


This report presents the absence of round ligament of femur associated with minimal evidence of developmental dysplasia of the hip. Absence of round ligament of femur is an uncommon variation. Several authors have reported about the biomechanics of round ligament of femur and management modalities for tears but there are very few studies about the incidence of absence of the round ligament of femur and so the absence was reported to be 2.8%.[7] Normally, the ligamentum teres femoris will be formed by the proliferation of mesenchymal cells around the hip joint. Failure of this proliferation is the possible explanation for the absence of round ligament of femur on the left side. As the femoral head was normal and well-formed along with fovea capitis, absence of round ligament was considered to be congenital, especially in the absence of any evidence of surgery. Most of the instances, fovea capitis will be hyoplastic if ligamentum teres is absent but in this case the fovea capitis is well developed.

Initially, it was thought that the main function of round ligament of femur was to transmit acetabular branch of obturator artery which supplies proximal portion of femoral head. However, contribution of this artery to the femoral head is very minimal only to the small subfoveal zone.[9] Due to the absence of round ligament of femur, acetabular branch of obturator artery is also absent. Major portion of blood supply of femur head is contributed by epiphyseal arteries. In adults, the epiphyseal arteries form an increased number of anastomosis around the femur head. Hence, absence of the acetabular branch of obturator artery would not be a major concern since it supplies only a minimal proximal portion of the femoral head and its absence would be compensated by the increased number of anastomosis around the femoral head by the epiphyseal arteries.

Although acetabular cavity appeared normal, left acetabular cavity is 0.7 cm shallower than the right acetabular cavity which raises a suspicion, as to whether there was an associated developmental dysplasia of the hip. However, in the absence of indications of surgery and because of the normal contour of the femoral head, associated developmental dysplasia was not considered. Other than shallow acetabular cavity on the left side, there are no other findings of developmental dysplasia of the hip. However, this shallow acetabular cavity is not ignorable because 18.67% of developmental dysplasia of the hip was associated with absent ligamentum teres femoris.[10]

Hence, in this case, he could have had developmental dysplasia of the hip in childhood which could have been treated conservatively which explains the normal femur head development and almost normally appearing acetabular cavity and explains the extremely laterally rotated left lower limb. Cause for this developmental dysplasia of the hip is attributed to be congenital. To conclude, observations in this case could be due to treated developmental dysplasia of the hip with associated absence of round ligament of femur on the left side.

The clinical significance of this ligamentum teres femoris is it acts as secondary stabilizer of the hip joint. In living beings, isolated absence of ligamentum teres femoris will be asymptomatic. If this absence of ligamentum teres femoris is associated with any osseous abnormalities, then the person will have hip instability and gait changes commonly like limping gait.[3] In this case, findings of developmental dysplasia of hip associated with absent round ligament of femur on the left side and with extremely laterally rotated left lower limb raises a suspicion that person could have had limping gait.


  Conclusion Top


There is unilateral absence of round ligament of femur associated with minimal evidence of developmental dysplasia of hip which is very rare. Cause of both could be congenital. To the best of our knowledge, this is the first case to report such variation in India. The knowledge of this variation will be important for radiologists and orthopedicians in the management of hip-related problems.

Acknowledgments

The authors sincerely thank those who donated their bodies to science so that anatomical research could be performed. Results from such research can potentially increase humankind's overall knowledge that can then improve patients care. Therefore, these donors and their families deserve our highest gratitude. Authors also thank all the faculties of the department of Anatomy and nonteaching staffs of the department.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Demange K, Kakuda C, Pereira CA, Sakaki M, Albuquerque R. Influence of the Femoral Head Ligament on HIP Mechanical Function; 2007. Available from: https://www.semanticscholar.org/paper/INFLUENCE-OF-THE-FEMORAL-HEAD-LIGAMENT-ON-HIP-Demange-Kakuda/1dd79ad90f6d36fdf8786287f2d8919a710ebc9b. [Last accessed on 2021 Dec 22].  Back to cited text no. 1
    
2.
Kivlan BR, Richard Clemente F, Martin RL, Martin HD. Function of the ligamentum teres during multi-planar movement of the hip joint. Knee Surg Sports Traumatol Arthrosc 2013;21:1664-8.  Back to cited text no. 2
    
3.
Martin HD, Hatem MA, Kivlan BR, Martin RL. Function of the ligamentum teres in limiting hip rotation: A cadaveric study. Arthroscopy 2014;30:1085-91.  Back to cited text no. 3
    
4.
Martin RL, Kivlan BR, Clemente FR. A cadaveric model for ligamentum teres function: A pilot study. Knee Surg Sports Traumatol Arthrosc 2013;21:1689-93.  Back to cited text no. 4
    
5.
Martin RL, Palmer I, Martin HD. Ligamentum teres: A functional description and potential clinical relevance. Knee Surg Sports Traumatol Arthrosc 2012;20:1209-14.  Back to cited text no. 5
    
6.
van Arkel RJ, Amis AA, Cobb JP, Jeffers JR. The capsular ligaments provide more hip rotational restraint than the acetabular labrum and the ligamentum teres: An experimental study. Bone Joint J 2015;97-B:484-91.  Back to cited text no. 6
    
7.
Perumal V, Techataweewan N, Woodley SJ, Nicholson HD. Clinical anatomy of the ligament of the head of femur. Clin Anat 2019;32:90-8.  Back to cited text no. 7
    
8.
Tan CK, Wong WC. Absence of the ligament of head of femur in the human hip joint. Singapore Med J 1990;31:360-3.  Back to cited text no. 8
    
9.
Kirici Y, Kilic C, Oztas E. The ligament of head of femur and its arteries. J Clin Anal Med 2010;1:22-5.  Back to cited text no. 9
    
10.
Li T, Zhang M, Wang H, Wang Y. Absence of ligamentum teres in developmental dysplasia of the hip. J Pediatr Orthop 2015;35:708-11.  Back to cited text no. 10
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1]



 

Top
 
  Search
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
    Access Statistics
    Email Alert *
    Add to My List *
* Registration required (free)  

 
  In this article
Abstract
Introduction
Case Report
Discussion
Conclusion
References
Article Figures
Article Tables

 Article Access Statistics
    Viewed164    
    Printed4    
    Emailed0    
    PDF Downloaded13    
    Comments [Add]    

Recommend this journal