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Russkikh A.N., Shabokha A.D., Kasimov V.I.
Krasnoyarsk State Medical University named after prof. V.F. Voino-Yasenetskiy, Krasnoyarsk, Russia
HISTOSTRUCTURE OF KNEE MENISCI IN THE MEN OF DIFFERENT BODY TYPES
The knee joint injury takes a leading place in
addressing for medical care in patients of working age. It is often accompanied
by degenerative and dystrophic diseases, disability and limited physiological
mobility of the joint [1, 2]. The issue of dissatisfaction with the offered
methods for prevention and treatment of such conditions is still actual.
Certainly, the knee joint is exposed to various types of load, and structural
changes are not distinguishable at the macrolevel, although changes in
microlevel are significant even in nonthreatening conditions [3].
Rybalko D.Yu. et al. (2015) investigated the histological structure of
various zones of human knee meniscus and identified some age characteristics.
They found that the knee meniscus structure was uniform with acellular regions
and regions with small amount (1-3) chondrocytes (the mean diameter from 11.19
± 3.02 to 12.51 ± 1.97 µm) in persons at the age ≤ 35 (mature age). With age,
the amount of chondrocytes and their diameter increase (to the maximal value –
22.01 µm), regions with maximal level of chondrocytes appear. Isogenous groups are
more common. The meniscus structure becomes ununiform and loose, with lower
percentage of elastic fibers. Such changes in meniscus suppose the development
of degenerative and dystrophic processes over age [3, 4].
At the same time, there are some described cases of
degenerative and dystrophic changes in knee meniscus and susceptibility to
different injuries in children, adolescents and persons at the age ≤ 35 [5].
Moreover, the statistical analysis of the results of the study by Rybalko D.Yu.,
and absence of statistically significant differences in some case suppose an
unknown factor of knee joint pathology [3, 4].
It has been proved that the risk of different diseases
is mainly related to life style, hypodynamia, excessive body mass and, not
least importantly, with body composition [3, 6-9]. For example, one of the last
studies by Gorbunov N.S. and Tutynin K.V. (2015), which was dedicated to
constitutional features of older women with trochanteric fractures and femoral
neck fractures, demonstrate a relationship between manifestation of diseases
and features of body composition. The study identified some evident
constitutional differences in older women with trochanteric fractures and
femoral neck fractures. So, according to the classification by Shevkunenko
V.N., women with femoral neck fractures demonstrate the dominance of persons of
dolichomorphic type, and a low percentage of persons of brachymorphic type of
body composition as compared to women with trochanteric fractures [10].
Such studies are multiple, and they suppose a presence
of a causal relationship between the locomotor system (particularly, the knee
joint) and features of body composition [1, 11, 12].
Considering the above-mentioned facts, the objective of the study was to
determine the histological structure of the man’s knee meniscus, taking into
account the features of his physique.
MATERIALS AND METHODS
The cadaveric male (age of 32-55) internal and
external menisci of both knee joints were investigated. The ethical principles
and the standards of the study were adhered (the extract from the protocol of
the local ethical committee of Krasnoyarsk State Medical University
No.39/2012, March 28, 2012).
After
standard fixation of the biological samples in 10 % formaline, the menisci were
sectioned at the level of their anterior and posterior horns and the body. The
hematoxylin-eosin stained histological specimens were exposed to microscopy,
estimation and morphometry of knee menisci specimen. The inclusion criteria
were absence of inflammatory and dystrophic changes in the hyaline cartilage.
The diameter of chondrocytes was estimated at different levels of meniscus
section. The amount of single cells and isogenous groups per square unit of
unchanged cartilaginous tissue were estimated.
The
constitutional approach allowed individualizing the results. The estimation of
body composition was conducted with the technique by W.L. Rees – Н.J. Eysenck, with first-priority estimation of anthropometric
parameters of the studied objects: the length of the body and the transverse
diameter of the chest [13]. The regional features were considered during
estimation of results of anthropometric study [8, 9, 14].
The statistical analysis was conducted with SPSS Statistics 17.0. The normalcy of distribution was estimated with
Shapiro-Wilk test. The characteristics of ordered samples for quantitative
signs with non-parametrical distribution and the data with parametrical
distribution (owing to low number) were presented with measure of central
tendency – mean (M), median (Me), mode (Mo) and measure of dispersion – mean
quadratic deviation, range, interquartile range [P25;
P75]. Non-parametric Mann-Whitney test (U-test) was used for
comparison of two independent samples of non-parametrical data, with its
critical value of 1,308 (with N = 84) for p < 0.05 and 1,189 for p <
0.01. Kruskal-Wallis test was used for comparison of three independent samples
of non-parametrical data [15].
RESULTS AND DISCUSSION
The study showed that the structure of the cartilage of the external and internal menisci of both knee joints included the perichondrium zone, where single spindle-shaped chondroblasts and the zones of new and mature cartilages without clear borders were visualized. At the background of prevailing intercellular space, the isogenous groups of chondrocytes (in lacunes) were found. As a rule, such accumulations consist of two-four cells. Such structure is common for all levels of histological sections of both menisci regardless of a side of examination of the male knee joints (the table 1).
Table 1. Histological characteristics of menisci of both knee joints in the men (n = 84)
|
Parameter |
Examination level |
Right knee joint |
Left knee joint |
p level |
|
Internal meniscus |
||||
|
Mean diameter of chondrocytes (µm) |
Anterior horn of meniscus |
11.62 |
11.74 |
НД |
|
Meniscus body |
12.33 |
12.12 |
НД |
|
|
Posterior horn of meniscus |
12.47 |
12.31 |
НД |
|
|
Amount of single cells (c.u.) |
Anterior horn of meniscus |
14.95 |
14.1 |
НД |
|
Meniscus body |
12.85 |
13.2 |
НД |
|
|
Posterior horn of meniscus |
13.68 |
13.8 |
НД |
|
|
Amount of isogenous groups of chondrocytes (c.u.) |
Anterior horn of meniscus |
1.29 |
1.33 |
НД |
|
Meniscus body |
1.35 |
1.32 |
НД |
|
|
Posterior horn of meniscus |
1.27 |
1.11 |
НД |
|
|
External meniscus |
||||
|
Mean diameter of chondrocytes (µm) |
Anterior horn of meniscus |
12.08 |
11.9 |
НД |
|
Meniscus body |
12.43 |
12.01 |
НД |
|
|
Posterior horn of meniscus |
12.34 |
12.34 |
НД |
|
|
Amount of single cells (c.u.) |
Anterior horn of meniscus |
15.07 |
14,7 |
НД |
|
Meniscus body |
12.72 |
13.01 |
НД |
|
|
Posterior horn of meniscus |
13.35 |
13.33 |
НД |
|
|
Amount of isogenous groups of chondrocytes (c.u.) |
Anterior horn of meniscus |
1.49 |
1.29 |
НД |
|
Meniscus body |
1.27 |
1.21 |
НД |
|
|
Posterior horn of meniscus |
1.06 |
1.64 |
НД |
|
Note: NA – no significant differences between the groups.
The detailed comparative analysis of the results of
morphometry of section of internal and external menisci of both knee joints
identified the absence of statistically significant differences between the
compared parameters of morphometry at different levels of a section, between
menisci and between the opposite sides. So, the mean diameter of chondrocytes was
11.62 [11.17; 11.97] µm at the level of the anterior horn of the internal right
knee meniscus. It did not differ statistically from the mean diameter of chondrocytes
of the anterior horn of the external meniscus of the same knee – 12.08 [11.68;
12.58] µm within the interquartile range P25-75. The similar picture is
observed in comparison with parameters of amount of some cells and amount of
isogenous groups of chondrocytes. The mean amount of individual cells was 13.69
[13.2; 14.2] (the level of the posterior horn of the internal right knee
meniscus), the average amount of isogenous groups of chondrocytes – 1.27 [1.0;
2.05] (the level of the body of the external right knee meniscus). Therefore,
the further text of the article demonstrate only the results of the comparative
analysis of the morphometric values of only medial meniscus of the right knee
joint in the men in the compared groups.
The further analysis of the results confirms the
presence of previous results of histological structure of knee menisci over age
described in the studies by Rybalko D.Yu. (2015) [3, 4, 5]. So, the structure
of knee menisci in the men (age ≤ 35) has the perichondrium with smooth borders
and single chondroblasts. There are some unevenly distributed isogenous groups
of chondrocytes (in lacunes) in the region of young and mature cartilage (Fig.
1).
Figure 1. Hyaline cartilage tissue of the anterior horn of
medial meniscus of the right knee joint of the men aged of 32. Hematoxylin and eosine
staining. Magnification × 400.I – perichondrium zone, 1 – isogenous group of
chondrocytes, 2 – single chondrocyte
The hyaline cartilage of knee menisci has some changes in men older 35. The number of chondrocytes in cartilaginous zones demonstrates visual increase. Single hypertrophied chondrocytes and events of karyopyknosis and karyorhexis appear. The number of isogenous groups increases (Fig. 2).
Figure
2. Hyaline cartilage tissue of the anterior horn of
medial meniscus of the right knee joint of the men aged of 48. Hematoxylin and eosine
staining. Magnification × 400. 1 – isogenous group of chondrocytes, 2 – a single
chondrocyte with evident lacuna
The estimation of morphological significance of the identified visual features in men of the second stage of mature age is not possible owing to minimal statistically reliable differences in the studied parameters which consist in only features of amount of isogenous groups of chondrocytes (the table 2).
Table 2. Histological characteristics of knee menisci in the men of 1st and 2nd periods of mature age (n = 84)
|
Parameter |
Examination level |
1st period of mature age |
2nd period of mature age |
p level |
|
Mean diameter of chondrocytes (µm) |
Anterior horn of meniscus |
11.62 |
11.39 |
НД |
|
Meniscus body |
12.33 |
12.18 |
НД |
|
|
Posterior horn of meniscus |
12.47 |
13.06 |
НД |
|
|
Amount of single cells (c.u.) |
Anterior horn of meniscus |
14.55 |
14.97 |
НД |
|
Meniscus body |
13.85 |
13.72 |
НД |
|
|
Posterior horn of meniscus |
14.08 |
14.05 |
НД |
|
|
Amount of isogenous groups of chondrocytes (c.u.) |
of meniscus |
1.09 |
1.28 |
НД |
|
Meniscus body |
1.85 |
1.16 |
НД |
|
|
Posterior horn of meniscus |
1.37 |
2,14 |
р < 0.05 |
Note: NA – no significant differences between the groups; * – differences are statistically reliable for comparison of the value of the examined parameter at the level of posterior horn of meniscus (p < 0.05).
The table 2 shows some statistically reliable
differences in comparison of parameters of isogenous groups of chondrocytes in
men of different age at the level of the posterior horn of menisci. Here, the
value of this parameter in men of the second period of mature age is 2.14 [2.0;
2.5] that is statistically higher than the similar parameter in men of the
first period of mature age (1.37 [0.9; 1.8], p < 0.05). Moreover, men of
this age group demonstrate the significantly higher amount of isogenous groups
of chondrocytes at the level of the posterior horn of meniscus in comparison
with the level of the body or the anterior horn of meniscus (1.16 [0.8; 1.8]
and 1.28 [1.1; 1.7] within the interquartile range Р25-75). Concerning such parameters
as mean diameter of chondrocytes and amount of single cells, they have not any
age features and are 12.18 [11.63; 12.75] (the level of meniscus body in men of
the second period of mature age) and 14.08 [13.2; 14.5] (the level of the
posterior horn of meniscus in men of the first period of mature age)
correspondingly.
As result of the anthropometric examination with subsequent somatotyping
(according to W.L. Rees – Н.J. Eysenck) of 84 male cadavers, 32 (38 %) showed the
pyknic type, 24 (28.5 %) – normosthenic type, 28 (33.5 %) – asthenic type. The
comparative estimation of the histological structure of menisci in men of
different body composition is presented in the table 3.
Table 3. Histological characteristics of knee menisci in the med of different body composition according to W.L. Rees – Н.J. Eysenck (n = 84)
|
Parameter |
Examination level |
Asthenic type |
Normosthenic type |
Pyknic type |
p level |
|
Mean diameter of chondrocytes (µm) |
Anterior horn of meniscus |
11.33 |
11.60 |
11.55 |
|
|
Meniscus body |
12.10 |
12.41 |
12.48 |
|
|
|
Posterior horn of meniscus |
12.15 |
12.44 |
13.08 |
р3-5,4-5 < 0.05 |
|
|
Amount of single cells (c.u.) |
Anterior horn of meniscus |
15.4 |
15.3 |
15.7 |
|
|
Meniscus body |
12.2 |
13.7 |
13.2 |
|
|
|
Posterior horn of meniscus |
13.4 |
13.4 |
11.1 |
р3-5,4-5 < 0.05 |
|
|
Amount of isogenous groups of chondrocytes (c.u.) |
Anterior horn of meniscus |
0.5 [0.45; 0.65]* |
1.1 [0.55; 1.2] |
1.3 [0.6; 1.7]* |
|
|
Meniscus body |
1.0 |
1.2 |
1.8 |
|
|
|
Posterior horn of meniscus |
1.2 |
1.2 |
2.3 |
р3-5,4-5 < 0.05 |
Note: * – differences are statistically reliable for comparison of values of parameters of different examination levels in the somatotype group (p < 0.05).
In comparison with age differences of histologic structure of menisci, the table 3 shows some constitutional features. First of all, the interesting fact is presence of statistically reliable differences in all examined parameters at the level of the posterior horn of menisci in men of pyknic type. At this level, the mean diameter of chondrocytes of knee menisci is 13.08 [12.77; 13.25] µm that is higher than the values at the level of the body and the anterior horn of menisci (11.55 [11.35; 11.86] and 12.48 [11.64; 12.58] µm correspondingly within the interquartile range Р25-75). Also men of this body composition demonstrate the minimal amount of single cells at the level of posterior horn of menisci (11.1 [10.3; 11.6] in 13.2 [11.85; 13.7] near the body and 15.7 [13.5; 15.3] in the plane of the anterior horn), and maximal value of amount of isogenous group – 2.3 [2.2; 2.5] (1.8 [1.2; 2.05] and 1.3 [0.6; 1.7] correspondingly at the level of the body and the anterior horn). The structure of the tissue is uneven, with chaotic position of isogenous groups, ruptured perichondrium with multiple increased chondrocytes with events of karyopyknosis (Fig. 3).
Figure
3. Hyaline cartilage tissue of the posterior horn
of medial meniscus of the right knee joint in a man of pyknic type. Hematoxylin
and eosine staining. Magnification × 400. 1 – isogenous group of chondrocytes,
2 – a single
chondrocyte
The comparative analysis of the morphometric
parameters of menisci at the level of the posterior horn of men of pyknic type
and men of asthenic and normosthenic types show the presence of the
statistically reliable differences. So, the mean diameter of chondrocytes in
the value of 13.08 [12.77; 13.25] µm at the level of the posterior horn is
higher than values of the parameter in asthenic and normosthenic types (12.15 [11.33; 12.3] and
12.44 [11.61; 12.67] correspondingly within the interquartile range Р25-75). Such reliable constitutional predominance of the parameter at the level
of the posterior horn of meniscus is common for amount of isogenous groups of
chondrocytes – 2.3 [2.2; 2.5]; it is reliably higher than in asthenic and
normosthenic types (1.2 [0.9; 1.3] and 1.2 [1.1; 1.4] µm correspondingly within
the interquartile range Р25-75).
For men of asthenic type, the common features are the
even structure of menisci, smooth perichondrium, absence of hypertrophied
chondrocytes and their stable diameter at different levels of a section (11.33
[11.17; 11.98] µm – the anterior horn, 12.10 [11.63; 12.31] µm – the body and
12.15 [11.33; 12.3] µm – the posterior horn). At the same time, there is a
statistically reliable difference in amount of chondrocytes and amount of
isogenous groups of chondrocytes inside the somatotypical group (the table 3,
Fig. 4). Amount of chondrocytes is 15.4 [14.25; 15.9] at the level of the
anterior horn of meniscus that is reliably higher than at the level of the body
and the posterior horn (12.2 [9.45; 13.5] and 13.4 [12.75; 14.05] correspondingly
within the interquartile range Р25-75). From other side, the amount of isogenous groups of
chondrocytes at the level of the anterior horn presents the minimal value as
compared to other levels (p < 0.05) and is 0.5 [0.45; 0.65] for the value of
this parameter 1.0 [0.8; 1.25] at the level of the body and 1.2 [0.9; 1.3]
at the level of the posterior horn.
Figure 4. Hyaline cartilage tissue of the posterior horn
of medial meniscus of the right knee joint in a man of asthenic type. Hematoxylin
and eosine staining. Magnification × 400. 1 – isogenous group of chondrocytes,
2 – a single chondrocyte
The histological structure of male menisci in
normosthenic men has a few differences from the structure of menisci in men of
hynecomorphic type (Fig. 5). The only difference is that all morphometric
parameters of menisci have not any statistically reliable differences at
different levels of histological examination (the table 3). The mean value of
diameter of chondrocytes is within 12.41 [11.66; 11.75] µm (meniscus body); amount
of chondrocytes within 13.7 [12.7; 14.1] (meniscus body); amount of isogenous
groups – 1.2 [1.15; 1.5].
Figure 5. Hyaline cartilage tissue of the posterior horn
of medial meniscus of the right knee joint in a man of normosthenic
type. Hematoxylin and eosine staining. Magnification × 400. 1 – isogenous
group of chondrocytes, 2 – a single chondrocyte
CONCLUSION
Therefore, the study confirms the presence of age features of histological structure of menisci and proves the fact that the constitutional features of the human influence on microstructure of knee menisci at different levels. The menisci in men of pyknic type, in contrast to other body types, are exposed to structural changes in histological picture at the level of the posterior horn, with predominant amount of isogenous groups of chondrocytes in minimal amount of chondrocytes with maximal diameter. Men of asthenic type are characterized by the increase in amount of single cells with minimal number of isogenous groups of chondrocytes at the level of the anterior horn of menisci in comparison with other parts of meniscus.
Information on financing and conflict of interests
The study was
conducted without sponsorship.
The authors
declare the absence of clear or potential conflicts of interests relating to
publishing this article.
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