The Morphometric Analysis of the Male Cadaveric Native Knees of the Ethnic Igbos of South East Nigeria and its Implication in Total Knee Replacement -

Abstract

Background:
In spite of its consideration as a very successful procedure nearly all total knee replacement (TKR) prostheses were designed based on the parameters of male 4,Western, and primarily white native knees. Mismatch between prosthesis and bone surface or malposition can lead to poor outcome of TKR.

Aim:
To determine the parameters of the native knee of the ethnic Igbos of South East Nigeria, determine any correlations amongst them ,compare the values with that of other populations and discuss its implication in total knee replacement.

Materials and method:
The study was carried out on male adult cadavers with normal knees found at the museum of the Department of Anatomy University of Nigeria and all cadavers whose knees were deformed or had any pathological condition were excluded from the study. There were 60 knees from 30 male cadavers. Measurements were taken independently from the distal femur and proximal tibia with a method with the aid of a Vernier sliding calipers.

Results:
The determined values of the parameters of the cadaveric knees in centimeters are as follows: FLAP: M=7.10,SD=.44, FMAP: M=6.83,SD=.42, FML:M=7.78,SD=.40, FAR: M=1.10,SD=.06, TLAP:M=4.65,SD=.23, TMAP:M=5.17,SD=.27, TML: M=7.88,SD=.29, TAR:M=1.53. SD=.06.

Conclusion:
The normal values of the knee parameters of the native knee of the ethnic Igbos of the South Eastern Nigeria has been established and these should be taken into consideration by medical engineers during component design and arthroplasty surgeon during total knee replacement. There are correlations between these parameters that could be useful as a decision making tool during TKR and finally, the differences between these parameters and that of ethnic Western and Asian populations should be noted by implant manufacturers and arthroplasty surgeons.

Full text

1013
© 2020 Nigerian Journal of Clinical Practice | Published by Wolters Kluwer ‑ Medknow
In spite of its consideration as a very successful procedure nearly all
total knee replacement (TKR) prostheses were designed based on the parameters
ofmale4,Western,andprimarilywhitenativeknees.Mismatchbetweenprosthesis
and bone surface or malposition can lead to poor outcome of TKR.  To
determine the parameters of the native knee of the ethnic Igbos of South East
Nigeria, determine any correlations amongst them ,compare the values with
that of other populations and discuss its implication in total knee replacement.
Materials and  The study was carried out on male adult cadavers with
normal knees found at the museum of the Department of Anatomy University of
Nigeria and all cadavers whose knees were deformed or had any pathological
condition were excluded from the study. There were 60 knees from 30 male
cadavers. Measurements were taken independently from the distal femur and
proximaltibiawithamethodwiththeaidofaVernierslidingcalipers. The
determined values of the parameters of the cadaveric knees in centimeters are as
follows: FLAP: M=7.10,SD=.44, FMAP: M=6.83,SD=.42, FML:M=7.78,SD=.40,
FAR: M=1.10,SD=.06, TLAP:M=4.65,SD=.23, TMAP:M=5.17,SD=.27, TML:
M=7.88,SD=.29, TAR:M=1.53. SD=.06.  The normal values of
the knee parameters of the native knee of the ethnic Igbos of the South Eastern
Nigeria has been established and these should be taken into consideration by
medical engineers during component design and arthroplasty surgeon during total
knee replacement. There are correlations between these parameters that could be
usefulasadecision making tool during TKR and nally,thedierencesbetween
these parameters and that of ethnic Western and Asian populations should be noted
byimplantmanufacturersandarthroplastysurgeons.
 Cadeveric knee morphometry, Ethnic Igbos, South East Nigeria,
total knee replacement



AU Katchy, AU Agu, E Esom, IT Ikele, MA Okeke, AU Ugwu
Address for correspondence: Dr. AU Agu,
Department of Anatomy, University of Nigeria, Enugu Campus,
Enugu, Nigeria.
E‑mail: augustine.agu@unn.edu.ng
of male,[4] Western, and primarily white native
knees.[5,6] Mismatch between prosthesis and bone surface
ormalpositioncanleadtopooroutcomeofTKR.During
TKRgreateortsare made toensurepropercomponent


The burden of osteoarthritis (OA) and its
management using total knee replacement (TKR)
have continued to increase nationally and globally
following increased life expectancy.[1,2] Many authors
have reported that patients with knee arthritis who have
had TKR have had their pain relieved with improve
function and enhanced quality of life.[3] In spite of its
consideration as a very successful procedure nearly all
TKR prostheses were designed based on the parameters
DepartmentofAnatomy,
Universityof Nigeria,Enugu
Campus,Enugu, Nigeria
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How to cite this article: Katchy AU, Agu AU, Esom E, Ikele IT, Okeke MA,
Ugwu AU. The morphometric analysis of the male cadaveric native knees
of the ethnic igbos of South East Nigeria and its implication in total knee
replacement. Niger J Clin Pract 2020;23:1013-21.

Received:
25-Dec-2019;
Revision:
31-Jan-2020;
Accepted:
24-Apr-2020;
Published:
03-Jul-2020
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Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
1014 Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
alignment and sizing in other to avoid overhang or under
sizing of the prosthesis which may result in a number
of severe complications including survivorship. Bonnin
et al.[7] have demonstrated that tibia prosthesis overhang
may result in the residual pain while Stulberg et al.[8]
demonstrated a close association between sinking and
under sizing of femoral prosthesis with high possibility
ofrevisions.
Authors who have carried out studies based primarily on
ethnicity have demonstrated variations among the ethnic
group of Western and East Asian populations.[9‑11] This
studyhadraisedthreequestionsfor determination.First,
what are the normal values of the knee parameters of
the native knee of the ethnic Igbos of the South Eastern
Nigeria. Second, are there any correlations between
these parameters? Third, are there any dierences
between these parameters and that of ethnic Western and
Asian populations? The study has further hypothesized
that there are no correlations between these parameters
and that there are no dierences in the native knees
values of the ethnic Igbos and that of Western and
Asian populations. Therefore, the purpose of this study
is to determine the parameters of the native knee of
the ethnic Igbos of South East Nigeria, determine any
correlations among them, compare the values with that
of other populations and discuss its implication in total
kneereplacement.

The study was carried out on male adult cadavers with
normal knees found at the museum of the Department of
Anatomy University of Nigeria and all cadavers whose
knees were deformed or had any pathological condition
were excluded from the study. There were 60 knees
from 30 male cadavers. Ethical approval obtained from
theethicscommitteOctober252019.
A para‑patella longitudinal incision about 15 cm
long [Figure1]wasmadethreengerbreadthproximal
tothepatella extendingdowntoanger breadthmedial
to the tibia tubercle and the knee exposed by deeper
dissections along the same incisional line separating the
junction between the rectus femoris and vastus medialis
proximally. The cadaver knees were exed and soft
tissues dissected away to expose the articular surfaces of
thedistalfemurandtheproximaltibia.
Measurements were taken independently from the distal
femur and proximal tibia with a method reported by
Kwak et al.[12]withtheaidof a Vernierslidingcalipers,
as shown in Figures2‑6.
A: Femoral Measurements: The three femoral
morphologic end points were measured as follows
1. Femoral medial lateral width at the condyle (FML):
Thiswas referenced by thefemoralepicondyle axis,
that was dened as the most salient point between
the medial and lateral attachment on the femoral
condyle Figure 2
2. Femorallateralanteriorposteriordimension (FLAP):
This was dened as the distance from the most
anterior point on the femur lateral condyle to the
posterior condylar line‑This is the longest dimensions
of the lateral condyle in the anterior posterior
dimension Figure 3
3. Femoralmedialanteriorposteriordimension(FMAP):
This was dened as the distance from the most
anterior point on the femur medial condyle to the
posterior condylar line‑This is the longest dimensions
of the medial condyle in the anterior posterior
dimension Figure 4
B.Thethreetibiamorphologicendpointsweremeasured
without resection of the tibia surface as follows:
1. Tibia medial lateral dimension (TML): This was
measured as the maximum length between the medial
andlateralplateau,paralleltotheaxisofthefemoral
condyle Figure 5
2. Tibia lateral anterior posterior dimension (TLAP):
This is the length from the most anterior point on
the lateral tibia plateau to the most posterior point
Figure 6
3. Tibia lateral anterior posterior dimension (TMAP):
This is the length from the most anterior point on
the medial tibia plateau to the most posterior point
Figure 7
Test‑retest reliability
To assess the testretest reliability some of the cadaveric
knees were measured on two occasions within 5 days
and the reliability of the repeated measures was
evaluatedusingscatterplotsandcorrelationcoecient.
 Knee incision providing access to the cadaveric knee
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Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
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Nigerian Journal of Clinical Practice ¦ Volume XX ¦ Issue XX ¦ Month 2020 1015
Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
Statistical analysis
WeusedtheIBMSPSSpackage(IBMCorp.,IBMSPSS
Statistics for Windows, Version 25.0, Armonk, NY,
USA), developed by International Business Machines
Corporation (IBM) to analyze our data. Descriptive
statistics were calculated for all variables of interest.
Continuous measures were summarized as means and
standarddeviations. The P values for comparing means
of continuous variables were determined after selecting
a level of signicance (α = 0.05).A one sample t‑test
was used for comparison with parameters of White,
Black, East Asian and Indian populations.The Pearson
correlationcoecientwasusedtodetermine correlation
betweenthekneeparameters.

Descriptive statistics‑Table 1
The determined values of the parameters of the
cadaveric knees in centimeters are as follows: FLAP:
FemoralMedialLateralDimensions(FML)Measurements FemoralLateralAnteriorPosterior(FLAP)measurements
FemoralMedialAnteriorPosterior(FMAP)Measurements TibialMedialLateral(TML)Measurements
Table
n Minimum  Mean 
Femorallateralcondyleanteriorposterior(FLAP)incm 60 1.9 5.8 7.7 7.10 0.44
Femoralmedialanteriorposterior(FMAP)incm 60 1.7 5.6 7.3 6.83 0.42
FemoralMediolateral(FML)incm 60 1.5 7.0 8.5 7.78 0.40
Femoral aspect ratio (FAR) in cm 60 0.23 1.0 1.3 1.10 0.06
Tibialateralanteriorposterior(TLAP)incm 60 0.8 4.3 5.1 4.65 0.23
Tibiamedialanteriorposterior(TMAP)incm 60 0.9 4.7 5.6 5.17 0.27
Tibiamediolateral(TML)incm 60 1.2 7.2 8.4 7.88 0.29
Tibia aspect ratio (TAR) in cm 60 0.3 1.4 1.7 1.53 0.06
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Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
1016 Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
M =7.10, SD =0.44,FMAP:M=6.83,SD=0.42,FML:
M=7.78,SD=0.40,FAR:M=1.10,SD=0.06,TLAP:
M = 4.65, SD = 0.23, TMAP: M = 5.17, SD = 0.27,
TML:M=7.88,SD=0.29,TAR:M=1.53.SD=0.06.
Correlation of knee parameters of the cadaveric
knees of ethnic Igbos‑ Table 2
Correlation of FML with TML, FLAP, FMAP and TMAP
When the FML dimensions were correlated with the
other parameters, the results of the Pearson correlation
indicated that there was a strong signicant positive
association with TML, (r (59) = 0.847, P < 0.05),
moderate signicant positive association with FLAP,
(r (59) = 0.621, P < 0.05), FMAP, (r (59) = 0.561,
P <0.05),andTMAP,(r(59)=0.694, P <0.05).
Correlation of FLAP with FMAP, FAR, TML, and TMAP
When the FLAP dimensions were correlated with
the other parameters and the results of the Pearson
correlation indicated that there was a strong signicant
positive association with FMAP, (r (59)=0.961,
P <0.05) and TML(r(59)=0.705, P < 0.05), moderate
Table
FML    TML    
FML PearsonCorrelation .621** .217 .561** .847** .694** ‑.167 .251
Sig.(2‑tailed) 0.000 0.096 0.000 0.000 0.000 0.202 0.054
n60 60 60 60 60 60 60 60
FLAP PearsonCorrelation 0.621** −0.628** 0.961** 0.705** 0.341** 0.175 −0.094
Sig.(2‑tailed) 0.000 0.000 0.000 0.000 0.008 0.181 0.477
n60 60 60 60 60 60 60 60
FAR PearsonCorrelation 0.217 −0.628** −0.639** −0.060 0.240 −0.374** 0.325*
Sig.(2‑tailed) 0.096 0.000 0.000 0.650 0.065 0.003 0.011
n60 60 60 60 60 60 60 60
FMAP PearsonCorrelation 0.561** 0.961** −0.639** 0.651** 0.397** 0.048 0.014
Sig.(2‑tailed) 0.000 0.000 0.000 0.000 0.002 0.714 0.915
n60 60 60 60 60 60 60 60
TML PearsonCorrelation 0.847** 0.705** −0.060 0.651** 0.662** 0.020 0.323*
Sig.(2‑tailed) 0.000 0.000 0.650 0.000 0.000 0.880 0.012
n60 60 60 60 60 60 60 60
TMAP PearsonCorrelation 0.694** 0.341** 0.240 0.397** 0.662** −0.735** 0.668**
Sig.(2‑tailed) 0.000 0.008 0.065 0.002 0.000 0.000 0.000
n60 60 60 60 60 60 60 60
TAR PearsonCorrelation −0.167 0.175 −0.374** 0.048 0.020 −0.735** −0.609**
Sig.(2‑tailed) 0.202 0.181 0.003 0.714 0.880 0.000 0.000
n60 60 60 60 60 60 60 60
TLAP PearsonCorrelation 0.251 −0.094 0.325* 0.014 0.323* 0.668** −0.609**
Sig.(2‑tailed) 0.054 0.477 0.011 0.915 0.012 0.000 0.000
n60 60 60 60 60 60 60 60
**Correlationissignicantatthe0.01level(2‑tailed).*Correlationissignicantatthe0.05level(2‑tailed)
TibialLateralAnteriorPosterior(TLAP)Measurements TibialMedialAnteriorPosterior(TMAP)Measurements
[Downloaded free from http://www.njcponline.com on Friday, July 3, 2020, IP: 197.210.226.109]

Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
1017
Nigerian Journal of Clinical Practice ¦ Volume XX ¦ Issue XX ¦ Month 2020 1017
Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
signicantnegativeassociationwithFAR,(r(59)=0.628,
P < 0.05), and a weak signicant positive association
withTMAP,(r(59)=0.341, P =008).
Correlation of FAR with FMAP and TAR other parameters
When the FAR dimensions were correlated with the other
parameters and the results of the Pearson correlation
indicatedthat there wasa moderate signicant negative
associationwith FMAP,(r(59)=0.639, P <0.05) and a
weaksignicantnegativeassociationwithTAR,(r(59)=
0.374, P =0.002).
Correlation of FMAP with TML and TMAP
When the FMAP dimensions were correlated
with the other parameters and the results of the
Pearson correlation indicated that there was a
moderate signicant positive association with TML,
(r (59)=0.651, P < 0.05) and a weak signicant
positive association with TMAP, (r (59)=0.397,
P =0.002).
Correlation of TML with TMAP and TLAP
When the TML dimensions were correlated with the
other parameters, the results of the Pearson correlation
indicated that there was a moderate signicant positive
association with TMAP, (r (59)=0.662, P < 0.05)
and a weak signicant positive association with
TLAP(r(59)=0.323, P <0.012).
Correlation of TMAP with TAR and TLAP
When the TMAP, dimensions were correlated with
the other parameters and the results of the Pearson
correlation indicated that there was a strong signicant
negative association with TAR, (r (59)=−0.735,
P <0.05)andamoderatesignicantpositiveassociation
withTLAP,(r(59)=0.668, P <0.05).
Correlation of TAR with TLAP
When the TAR dimensions were correlated with the other
parameters and the results of the Pearson correlation
indicatedthat there wasa moderate signicant negative
associationwithTLAP,(r(59)=−0.609, P <0.05).
Correlation of TLAP with TMAP
When the TLAP, dimensions were correlated with the
otherparametersandtheresultsofthePearsoncorrelation
indicated that there was a moderate signicant positive
associationwithTMAP,(r(59)=0.668, P <0.05).
Comparison of the mean FLAP dimensions of the
ethnic Igbos with that of White, Black, East Asian
and Indian populations‑Table 3
A One‑Sample Test Mean comparison of Mean
Table

Ethnicity  tdf    d
 Upper
White 6.4 12.307 59 0.000 0.6950 0.582 0.808 1.58
Black 6.6 8.766 59 0.000 0.4950 0.382 0.608 1.13
East Asian 6.1 17.620 59 0.000 0.9950 0.882 1.108 2.26
Indian 6.1 17.620 59 0.000 0.9950 0.882 1.108 2.26
FLAP=Femorallateralcondyleanteriorposteriorincm.SD=0.44.Mean=7.10.n=60
Table

Ethnicity  tdf    d
 Upper
White 6.5 6.18 59 0.000 0.3317 0.224 0.439 0.79
Black 6.5 6.18 59 0.000 0.3317 0.224 0.439 0.79
East Asian 6.0 15.50 59 0.000 0.8317 0.724 0.939 1.98
Femoralmedialcondyleanteriorposterior(FMAP)dimensionsincm.SD=0.42.Mean=6.83.n=60
Table

Ethnicity  tdf    d
 Upper
White 7.9 −2.295 59 0.025 −0.1183 −0.221 −0.015 −0.30
Black 7.1 13.222 59 0.000 0.6817 0.579 0.785 1.70
East Asian 7.6 3.524 59 0.001 0.1817 0.079 0.285 0.45
Indian 7.0 15.161 59 0.000 0.7817 0.679 0.885 1.95
Femoralmedialcondyleanteriorposterior(FML)dimensionsincm.SD=0.40.Mean=7.78.n=60
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Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
1018 Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
Parameters of the cadaveric knees of ethnic Igbos with
other ethnic groups for FLAP showed t (59)=12.307,
P = 0.000 and d = 1.58 for the white population,
t (59)=8.766, P = 0.000 and d = 1.13 for the black
population, t (59)=17.620, P = 0.000 and d = 2.26 for
the East Asian population and t(59)=17.620, P = 0.000
and d=2.26fortheIndianpopulation.
The FLAP dimensions (M = 7.10, SD.44) for the ethnic
Igbos were statistically signicant higher than that of the
White(M=6.4),Black(M=6.6),EastAsian(M=6.1),and
Indianpopulations(M=6.1).Theeectsizeswerelarge.
Thetestprovidedevidencetorejectthenull hypothesis.
Comparison of the mean FMAP dimensions of the
ethnic Igbos with that of white, black, and East
Asian populations‑Table 4
The study had hypothesized that the mean value of the
FMAP dimensions is not dierent from that of white,
black and East Asian populations and a one sample t test
was carried out to test this. The One‑Sample Test Mean
comparison of Mean Parameters of the cadaveric knees
of ethnic Igbos with other ethnic groups for FMAP
showed t(59)=6.18, P = 0.000andd=0.79 forthewhite
population,t(59)=6.18, P =0.000andd=0.79fortheblack
population, t (59)=15.50, P = 0.000 and d = 1.98 for the
EastAsian population. The FMAPdimensions(M=6.83,
SD.42) for the ethnic Igbos were statistically signicant
higher than that of the White (M= 6.5), Black (M =6.5),
East Asian (M = 6.0). The eect sizes were medium for
whiteandblackpopulationswhiletheeectsizeforwhen
comparedwiththeEastAsianpopulationwaslarge.
Thetestprovidedevidencetorejectthenull hypothesis.
Comparison of the mean FML dimensions of the
ethnic Igbos with that of white, black, East Asian
populations and Indian populations‑Table 5
The study had hypothesized that the mean value of the
FML dimensions is not dierent from that of white,
black, East Asian and Indian populations and a one
sample ttestwascarriedouttotest thishypothesis.
The One‑sample test mean comparison of mean
parameters of the cadaveric knees of ethnic Igbos with
other ethnic groups for FML showed t (59)=−2.30,
P = 0.025 and d=−0.30 for the white population,
t (59)=13.22, P < 0.05 and d = 1.70 for the black
population,t(59)=3.524, P =0.001and d=0.45forthe
EastAsianpopulation.
The FML dimensions (M = 7.78, SD = 0.40) for
the ethnic Igbos were statistically signicant lower
than that of the White (M = 7.9), but higher than that
of Black (M = 7.1), East Asian (M = 7.6).The eect
sizes were lower for white and East Asian populations,
whereas the eect size was larger when compared with
theBlackandIndianpopulations.
Thetestprovidedevidencetorejectthenull hypothesis.
Comparison of the mean FAR dimensions of
the ethnic Igbos with that of white and black
populations‑Table 6
The study had hypothesized that the mean value of the
FAR dimensions is not dierent from that of White and
Black populations and a one sample t test was carried
outtotestthis. TheOne‑sampletestmeancomparisonof
mean parameters of the cadaveric knees of ethnic Igbos
with other White and Black ethnic groups for FAR showed
t (59) =−15.783, P < 0.05 and d=−2.02 for the white
population and t(59)=−11.867, P <0.05andd=−1.52for
the black population. The FAR dimensions (M = 1.10,
SD = 0.06) for the ethnic Igbos were statistically
signicant lower than that of the White (M = 1.2) and
Black (M=1.19).Theeectsizeswerelarge.
Thetestprovidedevidencetorejectthenull hypothesis.
Comparison of the mean TLAP dimensions of the
ethnic Igbos with that of white, east Asian and
Indian populations‑Table 7
A One‑Sample Test Mean comparison of Mean
Parameters of the cadaveric knees of ethnic Igbos with
other ethnic groups for TLAP showed t (59)=−1.772,
P = 0.082, d=−0.22 for the white population,
t (59)=−1.772, P = 0.082, d=−0.22 for the East Asian
population and t(59)=15.977, P <0.05,d= 2.46forthe
Indianpopulation.
The TLAP dimension (M = 4.65, SD = 0.23) for the
ethnic Igbos was not statistically signicant dierent
from that of the White (M=4.7) and Black (M =4.7),
However,itwasstatistically signicant higher than that
of the Indian populations (M = 4.6) with a large eect
size.
Table

Ethnicity  tdf    d
 Upper
White 1.22 −15.783 59 0.000 −0.12093 −0.1363 −0.1056 −2.02
Black 1.19 −11.867 59 0.000 −0.09093 −0.1063 −0.0756 −1.52
Femoralaspectratio(FAR)dimensionsincm.SD=0.06,Mean=1.10.n=60
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Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
1019
Nigerian Journal of Clinical Practice ¦ Volume XX ¦ Issue XX ¦ Month 2020 1019
Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
The test failed to provide evidence to reject the null
hypothesis for the black and white populations but
providedevidencetorejectitwiththeIndianpopulation.
Comparison of the mean TMAP dimensions of the
ethnic Igbos with that of white, East Asian and
Indian populations‑Table 8
A One‑sample test mean comparison of mean parameters
of the cadaveric knees of ethnic Igbos with other ethnic
groups for TMAP showed t (59)=−3.759, P < 0.05,
d=−0.49 for the white population, t (59)=−0.940,
P = 0.351, for the East Asian population and
t(59)=1.880, P =0.065,fortheIndianpopulation.
The TMAP dimension (M = 5.17, SD = 0.27) for the
ethnic Igbos was statistically signicant dierent from
that of the White (M = 5.2) population with a medium
eect size. There was no statistically signicant
dierence when compared with that of the East
Asian (M=5.2)andIndian(M=5.1)populations.
The test provides evidence to reject the null hypothesis
for the white populations but failed to provide evidence
torejectitwiththeEastAsianandIndianpopulation.
Comparison of the mean TML dimensions of the
ethnic Igbos with that of white, black, East Asian
populations and Indian populations‑Table 9
The study had hypothesized that the mean value of the
TML dimensions is not dierent from that of white,
black, East Asian and Indian populations and a one
sample ttestwascarriedouttotest thishypothesis.
The One‑sample test mean comparison of mean
parameters of the cadaveric knees of ethnic Igbos with
Table

Ethnicity  tdf    d
 Upper
White 7.9 −0.543 59 .589 −0.0200 −0.094 0.054
Black 8.0 −3.260 59 0.002 −0.1200 −0.194 −0.046 −0.41
East Asian 7.7 4.890 59 0.000 0.1800 0.106 0.254 0.62
Indian 7.7 4.890 59 0.000 0.1800 0.106 0.254 0.62
Tibiamediolateraldimensions=TML.M=7.88.SD=0.29
Table

Ethnicity  Tdf    d
 Upper
White 1.57 −5.442 59 0.000 −0.0425 −0.058 −0.027 −0.71
Black 1.54 −1.601 59 0.115 −0.0125 −0.028 0.003
East Asian 1.53 −0.321 59 0.750 −0.0025 −0.018 0.013
Tibialaspectratio(TAR)dimensionsincm.SD=0.06,Mean=1.53.n=60
Table

Ethnicity  tdf    d
 Upper
White 5.3 −3.759 59 0.000 −0.1333 −0.204 −0.062 −0.49
East Asian 5.2 −0.940 59 0.351 −0.0333 −0.104 0.038
Indian 5.1 1.880 59 0.065 0.0667 −0.004 0.138
TMAP=TibiaMedialcondyleanteriorposteriorincm.SD=0.27,Mean=5.17,n=60


Ethnicity 
Mean
tdf 

Mean




d
 Upper
White 4.7 ‑1.772 59 0.082 ‑0.0517 ‑0.110 0.007 ‑
East Asian 4.7 ‑1.772 59 0.082 ‑0.0517 ‑0.110 0.007
Indian 4.6 15.977 59 0.000 0.5667 0.496 0.638 2.46
TLAP=Tibialateralcondyleanteriorposteriorincm.SD=0.23,Mean=4.65,n=60
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Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
1020 Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
other ethnic groups for TML showed t (59)=−0.543,
P = 0.589 for the white population, t (59)=−3.260,
P = 0.002, d=−0.41 for the black population,
t (59)=4.890, P < 0.05, d = 0.62 d = 0.45 for the East
Asian population and t (59)=4.890, P < 0.05, d = 0.62
and d=0.45fortheIndianpopulation.
TheTMLdimensions(M=7.88,SD=0.29)fortheethnic
Igbos was not statistically signicant dierent from that
oftheWhite(M=7.9), butwasstatisticallysignicantly
lower than that of Black (M = 8.0) with a weak eect
size. It was statistically signicant higher than that of
East Asian (M = 7.7) and Indian populations (M = 7.7)
with moderate eect sizes. The test did not provided
evidence to reject the null hypothesis. When compared
with the black population but provided evidence for
rejection of the null hypothesis when compared with that
ofEastAsianandIndianpopulations.
Comparison of the mean TAR dimensions of the
ethnic Igbos with that of white and black and East
Asian populations‑Table 10
The study had hypothesized that the mean value of the
TAR dimensions is not dierent from that of White,
Black and populations and a one sample t test was
carried out to test this. The One‑sample test mean
comparison of mean parameters of the cadaveric knees
ofethnicIgboswith otherWhite,Black,andEastAsian
ethnic groups for TAR showed t(59)=−5.442, P <0.05
and d=−0.71 for the white population, t (59)=−1.601,
P = 0.115 for the black population and showed
t(59)=−0.321, P =0.750fortheEastAsian population.
The TAR dimensions (M = 1.53, SD.06) for the ethnic
Igbos were statistically signicant lower than that of
the White (M = 1.57) with a moderateeectsizewhile
thedierencebetweenthemand that of Black and East
Asiansarenotstatisticallysignicant.The test provided
evidence to reject the null hypothesis with the White
population and fail to reject with the Black and East
Asianpopulations.

TKA has been used to treat disabling OA.[13,14] TKA
is a major surgery whose indications and outcome are
linked to a lot of variables including proper component
sizing.[15]
The study has determined the values of the distal femoral
morphology, proximal tibia morphology and the aspect
ratios for the native knees of the Igbo population of the
SouthEastNigeria.The importanceofthesedetermined
values cannot be over emphasized as properly shaped
prosthesis constructed based on these determined values
can provide the best coverage and avoid soft tissue
impingementinthekneesofthestudiedpopulation.
This study showed that the FML dimensions had a
strong signicant positive association with TML,
moderate signicant positive association with FLAP,
FMAP, and TMAP.This is incontrastwiththendings
of Mensch and Amstutz[16] who did not demonstrate any
correlations in these parameters in their study among the
Brazilianpopulations.
The FLAP dimensions had a strong signicant positive
association with FMAP and TML, moderate signicant
negative association with FAR and a weak signicant
positive association with TMAP. This is in consonance
with the ndings of Lakati et al.[17] who demonstrated
a similar correlation of these parameters among the
Kenyanpopulation.
ThisstudyshowedthattheFLAPandFMAPdimensions
were statistically signicantly higher than that of the
White, East Asian, and Indian populations with large
eect sizes. This should be given due consideration
during TKR in patients of Igbo extraction as medical
tourism continues to draw huge number of Nigerians
towardsthesecontinents.[18]
Most of the components used in the Igbo population are
designed based on White population knee data and this
may indeed lead to a mediolateral component overhang
inthestudiedpopulation.Prosthesisoverhangingismore
likely to cause soft tissue imbalance, and an abnormal
stress distribution in patellofemoral joint. During TKA
operation, there may be need to downsize the femoral
components to avoid this over hang arising from over
sized prosthesis. Sometimes, this may also result in an
undesirablecomplication,suchasnotchingoftheanterior
cortex which makes the femoral bone loose 40% of its
strengthandpredisposesittoperiprostheticfractures.[19‑22]
Inthesamevein,over‑resectionoftheposteriorfemoral
condylescanresultinanimbalance between the exion
andextensiongaps.[23]
The geometry of the proximal tibia is considered as an
important factor in TKA design and has a direct impact
onthebiomechanicsoftibiofemoraljoint.[24]
There was a comparison of the tibial plateau parameters
in this study and the TMAP values were larger than
that of TLAP, which is in consonance with ndings of
similarstudies.[25,26]
A comparison of the parameters obtained from the
proximal tibia, with that of Asia–Pacic population
including Chinese population did not show any
statistically signicant dierence unlike the ndings
of some authors,[27] who reported larger size in
this population. Our series showed the white had a
signicantlylargesize.
[Downloaded free from http://www.njcponline.com on Friday, July 3, 2020, IP: 197.210.226.109]

Katchy, et al.: Morphometric analysis of the male cadaveric native knees of the Ethnic Igbos, South East Nigeria
1021
Nigerian Journal of Clinical Practice ¦ Volume XX ¦ Issue XX ¦ Month 2020 1021
Nigerian Journal of Clinical Practice ¦ Volume 23 ¦ Issue 7 ¦ July 2020
A statistically signicant dierence in aspect ratio was
foundbetweenWhite,Black,andEastAsianpopulations
inthisstudy.The implication of these ndings is that it
is necessary to adjust the aspect ratio during components
designforachievingabetterclinicaloutcome.

The normal values of the knee parameters of the native
knee of the ethnic Igbos of the South Eastern Nigeria
has been established and these should be taken into
consideration by medical engineers during component
design and arthroplasty surgeon during total knee
replacement. There are correlations between these
parameters that could be useful as a decision making
tool during TKR and nally, the dierences between
these parameters and that of ethnic Western and Asian
populations should be noted by implant manufacturers
andarthroplastysurgeons.
Financial support and sponsorship
Nil.
Conicts of interest
Therearenoconictsofinterest.

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