430 Indian Journal of Forensic Medicine & Toxicology, July-September 2021, Vol. 15, No. 3 Morphometric Study of Dry Human Patella with Its Clinical Correlation
Pratima Baisakh1, Lopamudra Nayak2, B Shanta Kumari2, Saurjya Ranjan Das3 1Associate Professor, 2Assistant Professor, Dept of Anatomy, 3Associate Professor, Dept of Anatomy, IMS & SUM Hospital, SOA (Deemed to be University), Bhubaneswar, Odisha, India
Abstract Background- Patella is the largest sesamoid bone and forms the femuro-patellar component of the knee joint. Dimensions and classification of patellae are important anthropologically as well as clinically.
Aims & Objectives- Morphometry of patella has a definite role in implant design and reconstructive surgeries of knee joint. The present study aims to find out different dimensions of patella and its facets on both sides and compared.
Material & Methods- The morphometric study comprised of sixty (30 left and 30 right) dry human patella collected from department museum by using sliding digital calliper. The different parameters studied are height, width, thickness of patella, length and width of medial and lateral facets. Classification of patella was done by using the measurements of its articular facets.
Observations- The mean height, width, thickness of patella of left side were found to be 37.79mm, 38.26mm, 19.35mm and that of right side were 35.72mm, 34.91mm, 17.64mm respectively. The mean width of medial and lateral articular facet of left side were 19.42mm, 21.21mm and that of right side were 18.33mm,20.97mm respectively. Width of lateral articular facet is significantly larger than that of medial articular facet of same side(p<0.05) and 85% of patella belongs to Wiberg typeB.The mean patellar thickness on left and right side is 19.35mm & 17.64mm respectively,left side being significantly more than(P<0.05) that of right side.
Conclusion- These dimensions of patella may be helpful for different patellofemoral operations like knee arthroplasty, ligament repair, proximal tibial osteotomy, implant design for knee replacement and for forensic measurements.
Key words- Patella, morphometry, facets, knee joint.
Introduction because the position of tibial tuberosity vary in different individuals1-3.Superiorly placed, high-riding patella Patella is the largest sesamoid bone develop is called patella alta. An unusually small patella that in quadriceps femoris tendon. It forms the femuro- present above knee joint iscalled attenuated patella alta. patellar component of the knee joint. It is difficult when it is very low-riding in position it is called patella to specify the normal anatomical position of patella baja which can cause dysfunction during extension of knee joint4.It has a rough anterior surface, which has vertical ridges due to expansion of fibres from quadriceps Corresponding author: tendon. Its posterior surface is having large articular and Pratima Baisakh small nonarticular part. Articular part has two facets on Associate Professor, Department of anatomy IMS &SUM Hospital Siksha ‘O’ Anusandhan (Deemed either side of a median ridge. They articulate with the 5 to be University) Bhubaneswar, India corresponding facet on the patellar surface offemur . Phone - +91 9438844704 Each facet is divided by faint horizontal lines into equal Email- [email protected] thirds.A seventh ‘odd’ facet is presented by a narrow Indian Journal of Forensic Medicine & Toxicology, July-September 2021, Vol. 15, No. 3 431
strip along the medial border of the patella which comes departmental museum.The following parameters were in contact with the medial femoral condyle in extreme studied by using sliding digital calliper. flexion6. Lower non-articular part forms the apex of Patellar Height (PH)- Linear distance between patella &gives attachment to patellar ligament7. It is superior border and apex(Fig.1) involved in different postures like squatting,sitting andkneeling. Hence it is subjected to varied modification Patellar width (PW)- Linear distance between 8 depending on the ethnic and cultural variables .Patella medial and lateral border(Fig.2) gives protection to the knee joint anteriorly and increases the efficiency of quadriceps muscle during its extensor Patellar thickness (PT)- Linear distance between function acting as a fulcrum9.As it receives the insertion anterior surface and median ridge(Fig.3) of quadriceps femoris, its shape and size also affected Width of medial articular facet (WMAF)-Maximum by size and use of this muscle. Patella present as a shield distance between medial border and median ridge in anterior aspect of knee joint. Hence it is subjected to various type of trauma very often. Numerous pathologies Width of lateral articular facet (WLAF)-Maximum occur at patellofemoral unit leading to its degenerating distance between lateral border and median ridge changes. The various disordersthat affect patella are Statistical analysis- All statistical analysis was done osteoarthritis, fractures, chondromalacia patellae, by using statistical package for social science, window patellofemoral instability and idiopathic patellofemoral version 16 (SPSS-16 USA). Student t-test was used to pain syndrome. Knee arthroplasty and total knee find any significant difference exists between the right replacement is now a commonly performed procedure and left side patella. P<0.05 was taken as statistically to treat various knee problems. Outcome of knee significant. arthroplasty or patellofemoral arthroplasty is affected by 10 use of appropriate size and thickness of patella . Hence Result morphometry of patella has definite role in implant design and reconstructive surgeries occurring in the The mean values of different parameters of both sides knee joint. Wiberg classified patella into three groups were expressed in table1 &2. The mean height, width and basing on the position of median ridge, width of medial thickness of left side were 37.79mm(SD 4.11), 38.26mm and lateral articular facet11. Type A where Width of (SD 4.00) & 19.25mm(SD 1.91) (table1) and that of medial and lateral facet are same. Type B where Width right side were 35.72mm (SD 1.97),34.90mm(SD 2.11) of medial facet smaller than lateral facet and Type C and 17.54mm (0.73) respectively(table 2). Comparison where Width of medial facet much less than lateral facet. between different parameters of left and right side were Type B are common type ofpatella and it is the most reported in table 3. There is no significant difference stable variety. Any change in shape and size of patella in found in height and width of left and right-side patella. relation to tibial or femoral condylescan affects the knee Student’s test revealed thickness of left side patella is joint function.The present study carried out on different significantly more than that of right side(p<0.05). The morphometry of dry human patella of eastern Indian width of lateral articular facets were significantly larger origin, that have a great clinical importance for proper than the medial articular facet in both sides(P<0.05) functioning of knee joint and stability of patella. (table 3).According to Wiberg criteria, 85% patella belong to type B, 11.7% that of type A and 3.3% of type Materials & Methods C (table 4). The study was conducted on sixty dry human patella, 30 left & 30 right of unknown age & sex collected from 432 Indian Journal of Forensic Medicine & Toxicology, July-September 2021, Vol. 15, No. 3
Table 1; Measurements of left side patella
Measurements Mean (mm) Standard deviation Maximum (mm) Minimum (mm)
Patellar Height 37.79 4.11 43.75 33.49
Patellar width 38.26 4.00 45.42 33.91
19.25 Patellar thickness 1.91 22.67 16.50
Width of medial 19.42 2.61 23.20 15.21 articular facet Width of lateral 21.21 2.24 25.68 18.21 articular facet
Table 2; Measurements of right side patella
Measurements Mean (mm) Standard deviation Maximum (mm) Minimum (mm)
Patellar Height 35.72 1.97 39.65 39.65
Patellar width 34.90 2.11 37.67 31.76
18.68 16.76 Patellar thickness 17.54 0.73
Width of medial 18.33 1.29 20.53 16.65 articular facet
Width of lateral 20.97 1.27 22.77 19.26 articular facet
Table 3;Comparison between Left &Right side patella
Measurements Mean (mm) Mean (left) Mean (right) P value
Patellar Height 36.75 37.79 35.72 0.22
38.26 Patellar width 36.58 34.90 0.15
Patellar thickness 18.39 19.35 17.64 0.03
Width of medial 18.33 18.87 19.42 0.96 articular facet
Width of lateral 21.09 21.21 20.97 1.14 articular facet
P value (WMAF/ 0.01 0.02 WLAF)
Indian Journal of Forensic Medicine & Toxicology, July-September 2021, Vol. 15, No. 3 433
Table 4; Wiberg’s classification of Patella
Type Number of patella %
A 7 11.7
B 51 85
C 2 3.3
Figure 1; measurement of patellar Height
Figure 2; Measurement of Patellar width 434 Indian Journal of Forensic Medicine & Toxicology, July-September 2021, Vol. 15, No. 3
Figure 3; Measurement of patellar thickness
Discussion morphometry. The patellar height is an important factor for different knee surgery, cruciate ligament repair or Patella, the largest sesamoid bone present in anterior proximal tibial osteotomy to prepare knee implants18. aspect of kneeforming patello-femoral component of The thickness of left side patella is significantly higher knee joint. It gives attachment to quadriceps at its base than right side(p<0.05).That may be due to larger size and patellar ligament at the apex. It plays an important of quadriceps tendon in this side but it needs further role in extensor mechanism of knee joint acting as study. The width to thickness ratio is almost 2:1 which alever12. Its size and shape depend on the strain produced is represented in the graph 1.This finding coincides with by use of quadriceps13. In the present study the mean the study by Chhaparwala et al. This relation between height, width and thickness were 36.75mm(SD 3.04), height and width help in making patellar implant designs. 36.58mm(SD 3.05), and 18.39mm(SD 1.32) respectively. In the present study width of MAF and LAF in left side These findings can be correlated with the study by were 19.42mm & 21.21mm respectively. Similarly, in Murugan et al (2017) where the mean height, width right side it is 18.33mm & 20.97mm respectively. The and thickness were 38.07mm(SD 3.79), 38.58mm(SD WLAF was found significantly larger than than WMAF 3.81) and18.29mm(SD 1.73) respectively14. Thevalues in both sides. It is in contrast to study by Murugan et reported in present study can also be compared with al and Chhaparwala et al as they didn’t find any such another study by Chhaparwala et al in which they reported significant difference. This may be due to larger lateral the mean height and width were 36.67mm(SD 3.38) femoral articular surface for patella in these population. and 38.67mm(SD 3.91), but thickness is 19.26mm(SD This should be taken into consideration while doing knee 1.33) which is more than present study15.It may be surgery with prosthesis. Basing on WMAF and WLAF due to racial difference, method of measurement, age, 85% of patella belong to Wiberg type B where width of sex and body mass index. On comparison to study on medial articular facet less than width of lateral articular Chinesepopulation by Shang Peng et al in 2014 where facet (table). This type of patella is more stable than other the width was found to be 44.13mm and that by Oladrian variety11. Type A varity is found in 11.7% where width et al in 2013 on South Africans, it was 45.14mm which of MAF is equal to width of LAF and type C in 3.3% was high compared to the present study16,17. This of total studied patella where width of MAF is much shows there is strong influence of race on patellar Indian Journal of Forensic Medicine & Toxicology, July-September 2021, Vol. 15, No. 3 435
smaller than LAF so that central ridge is barely visible. 8) Agnihotri G, Kaur R, and Kalyan V, “Patellar Another study by Koyuncu on fetal cadaver showed shape, nose pattern and facet configuration, 20% patella are type A, 50% belong to type B and 30% InternationalJournal of Current Research and belong to type C19. The present study was carried out on Review, 2013; 5(14), 30–35, different morphometry of dry human patella of eastern 9) Kaufer H. Mechanical function of the patella. Indian origin, that have a great clinical importance for Journal of bone and Joint Surgery 1971;53(8): proper functioning and stability of of knee joint during 1551-1560. arthroplasty 10) Muhamed R, Saralaya VV, Murlimanju BV, Chettiar GK. In vivo magnetic resonance imaging Conclusion morphometry of the patella bone in South Indian population. Anatomy & Cell Biology. Various parameters studied in present work on 2017;50(2):99-103. Indian population can be utilised in orthopaedic surgeries 11) Wiberg G. Roentgenographic and anatomic studies for prosthesis/implant designs, knee replacement on the femoropatellar joint. Acta Orthop Scand. and reconstructive surgeries.An appropriate size and 1941; 12:319–410. thickness of a patellar implant is important in ensuring 12) Upadhyay S, Raza HKT, Srivastava P. Position success in the functionality of arthroplasty.This study of the patella in adults in central India:Evaluation will help in restoration of the normal biomechanics of the Insall-Salvati ratio. Journal of Orthopaedic of the patellofemoral unit, that should be taken into Surgery, 2013;21(1):23-7 consideration during knee repair. 13) Ahmed A and Mohammed-L. Human patella morphometry and volumetry, and osteology-based Conflicts of Interest: Authors have no conflicts of study in the japanese ethnicity. ejpmr, 2016,3(10), interest 388-396 Source of Funding: Self 14) Murugan M, Ambika S, Nim VK. KNEE CAP: A MORPHOMETRIC STUDY. International Journal Ethical Clearance: The study was approved by of Anatomy and Research, Int J Anat Res 2017, Vol institutional ethical committee. 5 (1) :3556-59 15) Chhaparwal R, Hiware S,Chhaparwal P, References Chhaparwal N. Morphometric Study of Knee Cap 1) Scuderi GR The patella, Springer VerlagNew York, (Patella). Ann. Int. Med. Den. Res. 2018;4(6):05-09 1995; USA. 16) Peng S, Linan Z, Zengtao H, Xueling B et al. 2. Flandry F, Hommel G Normal Anatomy and Morphometric measurements of the patella on Biomechanics of the Knee. Sports Med Arthrosc 3D model reconstructed from CT scan images Rev 2011; 19: 82-92. forthe southern Chinese population. Chin Med J, 2014;127(1): 3. Cunningham C, Scheuer L, Black S Developmental Juvenile Osteology. Academic Press-Elsevier, 17) Oladrin I, Philander I, Bidmos MA.Morphometric London.2016 analysis of the patella and patellar ligament of South Africans of Europeanancestry. S Afr J 4. Weerakkody Y and Gaillard F. Patella Sci.2013;109:9-10. baja Radiopaedia. Retrieved 2018 18) Christian, B., Alexandre, Z., Rodrigo, P., Eduardo, 5) Dutta. A. K. Patella- Chapter 15 in 3rd edition, B. Naasson, C. Comparitive evaluation of patellar Current book international, Kolkata 2004: 145. height methods in the Brazilian population. Revista 6) Standring S, Gray’s Anatomy, 40th Edition, Brasileira De Ortopedia, 2016;1(1):53-57 Churchill Livingstone Elsevier,2008 19) Koyuncu E, Cankara N, Sulak O, Özgüner G, 7) Olateju OI, Philander I, Bidmos MA. Morphometric Albay S. The morphometry of patella and patellar analysis of the patella and patellar ligament of ligament during the fetal period. Clin Anat. 2011; South Africans of European ancestry. S Afr J Sci. 24:225– 231. 2013;109(9/10)