Alain Fontbonne
email: alain.fontbonne@vet-alfort.fr

Sylwia Prochowska

Zuzanna Niewiadomska

PhD, Dipl Alain Fontbonne Dvm

Infertility in purebred cats -a review of the potential causes

Keywords: infertility, queen, teratospermia, mismating, purebred, cat

Although purebred cat breeding is growing in popularity in European countries, most research and publications concern dog reproduction. Infertility in queens has been poorly studied. It may not come as a surprise as common domestic shorthair cats are well known for their excellent fertility. However, even in the latter, the infertility rate is around 20%. Only recently, published articles have analyzed the reproductive performances in different breeds, for example in UK, Sweden, France and Italy, and found similar figures.

In cats, infertility may arise from many factors such as mismating, prolonged anestrus or silent heats, hormonal, nutritional, genetical or chromosomal causes. Also, infectious diseases, probably frequent in breeding facilities, include pathological agents that are well recognized as having a negative effect on pregnancy or other pathogens for which the involvement in fertility problems is unclear. However, analyzing the literature, it appears that the most prevalent causes of infertility in pedigree cats may well be, in females, uterine

Introduction

In veterinary medicine and research, the cat remains under-studied, and there is still an unbalanced weight of scientific publications in favour of dogs [START_REF] Sparkes | Feline research: Where have we come from and where are we going?[END_REF]. It is the same for feline reproduction. For example, during the last EVSSAR congress in Berlin (Germany) in June 2019, among 166 submitted presentations that were selected by the scientific committee and which had their abstract printed in the proceedings, only 24 (14.5%) presented some data related to cat reproduction. There is therefore an emergency for specialists to become involved in dedicated research on feline reproduction. Cat breeding is now growing fast all over Europe and the western world, and cat breeders and owners are seeking specific data and dedicated reproductive techniques and treatments. Furthermore, most published studies have been based only on data recovered from domestic shorthair cats, and feline breed reproductive specificities are unclear and not well studied.

Is infertility a reality among purebred cats?

Infertility is defined as the inability to conceive and produce viable offspring. In our modern societies, cat over-population is a major concern, and it may appear illogical to enlarge research about fertility problems. However, infertility is a major concern for breeders of purebred cats, as it causes financial and genetic loss, together with personal disappointment and concern for the future.

There are very few published figures about infertility in cats. [START_REF] Swanson | In Vivo Embryogenesis, Embryo Migration, and Embryonic Mortality in the Domestic Cat1[END_REF] [START_REF] Swanson | In Vivo Embryogenesis, Embryo Migration, and Embryonic Mortality in the Domestic Cat1[END_REF] performed early embryonic collections after natural matings in 48 domestic shorthair ovulating queens, and found that 38 (79.2%) of them produced good-quality embryos or had implantation sites. From the remaining cats, only unfertilized oocytes (n=5), degenerating embryos (n=4) or no oocytes/embryos (n=1) were recovered. Therefore, around 20% of these queens would have remained infertile if the pregnancy had been left to continue. In purebred cats, infertility is still an enigma, with very few specific articles [START_REF] Romagnoli | Failure to conceive in the queen[END_REF][START_REF] Axnér | Infertility in the cycling queen: seven cases[END_REF]. The question raised is of course about the reality of infertility. Recent published data about the reproductive performances of pedigree cats in different countries help us quantifying fertility problems in this species: United Kingdom [START_REF] Sparkes | A questionnaire-based study of gestation, parturition and neonatal mortality in pedigree breeding cats in the UK[END_REF], Sweden [START_REF] Holst | The Swedish breeding cat: population description, infectious diseases and reproductive performance evaluated by a questionnaire[END_REF], France [START_REF] Fournier | Epidemiological analysis of reproductive performances and kitten mortality rates in 5,303 purebred queens of 45 different breeds and 28,065 kittens in France[END_REF] and Italy [START_REF] Romagnoli | Fertility parameters and reproductive management of Norwegian Forest Cats, Maine Coon, Persian and Bengal cats raised in Italy: a questionnaire-based study[END_REF]. Ström- [START_REF] Holst | The Swedish breeding cat: population description, infectious diseases and reproductive performance evaluated by a questionnaire[END_REF] analyzing the results of a questionnaire sent to Swedish cat breeders found that 32% of breeders claimed that some of their queens didn't conceive after mating [START_REF] Holst | The Swedish breeding cat: population description, infectious diseases and reproductive performance evaluated by a questionnaire[END_REF].

Furthermore, around 10% of presumably pregnant queens -showing some degree of abdominal development and mammary enlargement around one month of pregnancy -did not produce kittens, which may have been the results of in utero embryonic resorption. Fournier et al. in 2017 [START_REF] Fournier | Epidemiological analysis of reproductive performances and kitten mortality rates in 5,303 purebred queens of 45 different breeds and 28,065 kittens in France[END_REF] analyzed the reproductive performances of 5203 French pedigree queens from 45 different breeds, and found that around 15% of mated queens were not pregnant.

Furthermore, there was a difference on the pregnancy rate between different breeds, with extremes values varying from 58.1% (117 oestruses) in Oriental queens up to 100% (15 oestruses) in Burmese cats. Subjective reports from cat breeders claimed that 8.2% of apparently pregnant queens (see supra) failed to maintain their pregnancy. These reports lead us to think -as a preliminary conclusion -that infertility and pregnancy losses are a reality among purebred cats, and therefore it appears as an obligation to study the potential causes of this problem.

Mating problems and ovulation disorders.

Time of mating

In the dog, inappropriate breeding management is often stated as a frequent cause of infertility. Is it also found in cats? Cat breeders declare that 75% of the matings occur during the first 3 days of oestrus [START_REF] Fournier | Epidemiological analysis of reproductive performances and kitten mortality rates in 5,303 purebred queens of 45 different breeds and 28,065 kittens in France[END_REF], which is considered as the ideal time for the breeding. However, many owners remove their queens from the male as soon as some matings have been observed. In domestic shorthair cats, [START_REF] Donoghue | Influence of day of oestrus on egg viability and comparative efficiency of in vitro fertilization in domestic cats in natural or gonadotrophin-induced oestrus[END_REF] [START_REF] Donoghue | Influence of day of oestrus on egg viability and comparative efficiency of in vitro fertilization in domestic cats in natural or gonadotrophin-induced oestrus[END_REF] found that follicular oocytes eventually ovulated after matings performed on the first day of oestrus are immature and of poor quality. It may not be recommended to leave queens to be mated only on the first day of oestrus, as more than 85% of queens ovulated in response to three matings on the second or third day of oestrus [START_REF] Swanson | In Vivo Embryogenesis, Embryo Migration, and Embryonic Mortality in the Domestic Cat1[END_REF] and even 100% of queens ovulated after multiple copulations on the 3 rd day of the heats [START_REF] Concannon | Reflex LH Release in Estrous Cats Following Single and Multiple Copulations[END_REF].

Spontaneous ovulation

Other problems may lead to feline infertility although the mating was performed in apparently good conditions. One of them is the phenomenon of so called "spontaneous ovulation", that is an ovulation which appears without any coitus. This is especially frequent in breeding catteries. In domestic shorthair queens living in groups of females, the level of spontaneous ovulations may be as much as 39-87% [START_REF] Gudermuth | Incidence of spontaneous ovulation in young, group-housed cats based on serum and faecal concentrations of progesterone[END_REF][START_REF] Binder | Spontaneous ovulation in cats-Uterine findings and correlations with animal weight and age[END_REF], and may be more frequent in queens with a higher bodyweight [START_REF] Binder | Spontaneous ovulation in cats-Uterine findings and correlations with animal weight and age[END_REF]. This may also represent a real problem in pedigree queens as many of them are living with other females, and may have already ovulated when they are brought to the male for the mating.

Anovulatory cycles

A queen may fail to ovulate despite mating, if for example the number or frequency of matings are too low, as it is well known that only 50% of the queens ovulate after a single mating [START_REF] England | BSAVA Manual of Canine and Feline Reproduction and Neonatology[END_REF]. The role of the stimulation of ovulation induced by the penile spines is unclear.

In any case, the penis of the tom should be examined to confirm full development of these spicules.

Stress and inexperience

However, other problems may occur during mating. An aggressive or an abnormally stressed female may not accept the male. Some breeders report that single females lie on their back to avoid being penetrated (personal data). In cats, there is probably a partner preference, as queens accepted to be mated in only 15/38 (39.5%) attempts despite confirmed oestrus [START_REF] Malandain | Follicular growth monitoring in the female cat during estrus[END_REF].

However this has to be further studied. Mating not necessarily occurs, when partners are put into the same room. Failure to mate may happen when partners are too immature or inexperienced, or in breeds, where male with low libido are a problem. We frequently observed this in Persian or Maine Coons (personal data).

Anatomical and health problems

Anatomical problems in males and females may prevent penetration, such as a preputial hair ring in longhaired cats, preputial or penile problems (phimosis…) in males [START_REF] Zambelli | Clinical approach to the infertile male. 2nd edition[END_REF] or vaginal or vulvar atresia in females. Furthermore, lack of teeth or pain in the mouth or jaws because of stomatitis, can render a male incapable to grab the neck of the female during mating; procedure necessary for stabilization [START_REF] Zambelli | Clinical approach to the infertile male. 2nd edition[END_REF]. 2.6 A practical approach to mating or ovulation disorders.

What recommendations could therefore can be made to improve the timing of mating and to recognize spontaneous ovulations? Veterinarians could propose to pedigree cat owners to perform a vaginal smear on the day when they intend to mate a queen, so as to insure that she is in full oestrus, with more than 85% keratinized cells [START_REF] Malandain | Follicular growth monitoring in the female cat during estrus[END_REF]. It may also be interesting -in queens that permit it -to perform an oestrus follow-up of the follicular maturation during the first three days of oestrus by ovarian ultrasonography, or at least, to perform this examination on the day of the mating, as it has been shown that at the pre-ovulatory stage, at least one follicle reaches a diameter greater than 3.0 mm [START_REF] Malandain | Follicular growth monitoring in the female cat during estrus[END_REF]. It may therefore help to see, whether the follicular maturation is clearly at an early stage, or whether the queen has already ovulated, showing a complete follicular collapse under ultrasound examination. Although progesterone blood level begins to increase only after ovulation, it may be interesting to measure the concentration to make sure that it is basal on the day of the mating.

To ensure that penetration has occurred, a vaginal smear or a vaginal wash soon after an observed mating to control the presence of spermatozoa can be performed [START_REF] Johnston | Canine and feline theriogenology[END_REF]. Finally, to ensure that ovulation has occurred, blood should be taken one to three weeks after the last observed mating to measure blood progesterone. In case of an anovulatory cycle, the value will remain basal [START_REF] Axnér | Clinical approach to conditions of the non-pregnant and neutered queen[END_REF]. In case of confirmed anovulatory cycle, induction of ovulation can be tried during the next cycle; even though in cats, there is no standardized protocol for induction of ovulation at the time of natural mating. Preliminary data in our department have shown that a series of 5 vaginal stimulations at 30 minutes interval on females at the peak of oestrus induced ovulation in 8/11 queens (unpublished results). This is preferable, since hormonal stimulation can cause side effects. In one study, induction of ovulation with hCG lead to disruption of oviductal embryo transport and development, probably due to abnormal endocrine environment [START_REF] Graham | Chorionic gonadotropin administration in domestic cats causes an abnormal endocrine environment that disrupts oviductal embryo transport[END_REF], although successful ovulation was induced in queens in nonbreeding season by administration of eCG and hCG before embryo transfer in the study of the team of Tsutsui [START_REF] Tsutsui | Feline Embryo Transfer during the Non-Breeding Season[END_REF]. Induction of ovulation can also be performed with GnRH in combination with vaginal stimulations [START_REF] Kanca | Vaginal cytology after induction of ovulation in the queen: Comparison of postoestrus and dioestrus[END_REF].

Finally, veterinarians should advise the cat owners to observe carefully the post-coital reaction of the queen, as only a frantic rolling on the back is a behaviour that proves in 100% of cases that a penetration by the male has really occurred. Vulvar licking, screaming or chasing the male are not proof that coitus has occurred [START_REF] Root | Estrous length, pregnancy rate, gestation and parturition lengths, litter size, and juvenile mortality in the domestic cat[END_REF].

Uterine pathology: an under-estimated cause of infertility?

In her study on infertile purebred queens belonging to 6 different breeds, Axner et al. ( 2008) [START_REF] Axnér | Infertility in the cycling queen: seven cases[END_REF] found that in 4/7 cases a uterine pathology was diagnosed: two cases of cystic endometrial hyperplasia (CEH), one case of pyometra with acute endometritis and one case of suspected mild endometritis. The question remains whether uterine problems are a major cause of infertility in cats?

Endometritis

In dogs, sub-clinical endometritis is a severe problem [START_REF] Mir | Findings in uterine biopsies obtained by laparotomy from bitches with unexplained infertility or pregnancy loss: an observational study[END_REF][START_REF] Gifford | Histopathologic findings in uterine biopsy samples from subfertile bitches: 399 cases (1990-2005)[END_REF]. However, still today the pathogenicity of sub-clinical endometritis is unclear. Above all, the presence and the exact role of bacteria remains unclear. In an observation, among 7 infertile purebred queens, vaginal bacteria were isolated in all cases. Two queens with a profuse bacterial growth were treated with antibiotics became pregnant later [START_REF] Axnér | Infertility in the cycling queen: seven cases[END_REF].

In another study, culture of uterine content was performed in 22 cats suffering from inflammatory uterine diseases or infertility. All isolation attempts yielded growth and E.coli was the organism most commonly isolated [START_REF] Lawler | Histopathologic features, environmental factors, and serum estrogen, progesterone, and prolactin values associated with ovarian phase and inflammatory uterine disease in cats[END_REF].

In cats, mild endometritis can be difficult to diagnose. From her study in 2008, Axnér et al. concluded that "low grade endometritis is extremely difficult to diagnose in the queen and its incidence and importance as a cause of infertility are unknown" [START_REF] Axnér | Infertility in the cycling queen: seven cases[END_REF]. Indeed, surgical biopsies preferentially performed in dioestrus at the time of diagnosis by ultrasonography of lack of pregnancy or embryonic resorption, appear as the "gold standard". The procedure allows histological, bacteriological and even molecular examination of samples; the latter for the detection of microbial antigens by means of PCR. However, our experience shows that cat breeders are often reluctant to accept this invasive procedure. Trans-cervical uterine flushing with a sterile saline solution has become a potential diagnostic tool since it has been demonstrated that trans-cervical catheterization with endoscopic guidance is possible in the queen [START_REF] Zambelli | Endoscopic transcervical catheterization in the domestic cat[END_REF]. Preliminary unpublished trials in our laboratory with a 1.9 mm diameter rigid endoscope (ref. 67030BA, Karl Storz, Germany) revealed that it is a useful tool and deserves further investigation.In subfertile queens, it is essential to perform an early diagnosis of pregnancy by ultrasound, as early as 10 to 15 days after the last observed mating, to diagnose an eventual embryonic death; furthermore, the uterine clearance can be observed. In bitches, [START_REF] Freeman | Prevalence and effect of uterine luminal free fluid on pregnancy and litter size in bitches[END_REF] found that the presence of uterine luminal fluid on day + 5 or +14 after a mating was associated with a significantly reduced pregnancy rate, and that no bitches in which fluid was present at day + 14 became pregnant [START_REF] Freeman | Prevalence and effect of uterine luminal free fluid on pregnancy and litter size in bitches[END_REF]. Indeed, [START_REF] Axnér | Infertility in the cycling queen: seven cases[END_REF] observed that 4/7 infertile queens showed intra luminal fluid sonographically at the time of the clinical examination [START_REF] Axnér | Infertility in the cycling queen: seven cases[END_REF].

Furthermore, recent publications have begun to investigate the uterine blood flow in the course of pregnancy. The aim is the early detection of potential anomalies. Doppler sonography allows examination of maternal and fetal arterial blood flow, and normal parameters are available, helping to recognize abnormalities [START_REF] Blanco | Doppler ultrasonographic assessment of maternal and fetal arteries during normal feline gestation[END_REF].

In one study, pregnancy arrest was induced in queens by using the anti-progestine aglepristone. Authors observed an abnoemal increase in the resistancy index of the uterine artery together with the embryonic death [START_REF] Blanco | Evaluation of feline uterine and umbilical arteries blood flow in a pharmacologically induced abnormal gestation model[END_REF]. But to the best of our knowledge no such measures have been published in field pathological conditions.Markers of uterine inflammation, such as C-reactive protein (CRP), prostaglandin 15-ketodihydro-PGF2alpha metabolites (PGFM) or serum amyloid A, may be a promising diagnostic approach, although mostly experimental at the moment and mainly orientated towards the diagnosis of pyometra in dogs [START_REF] Hagman | Molecular aspects of uterine diseases in dogs[END_REF]. One recent study in cats has been published [START_REF] Vilhena | Acute phase proteins and antioxidant responses in queens with pyometra[END_REF].

Cystic endometrial hyperplasia

This potentially -but still to be proved -detrimental role of sub-clinical endometritis should not let us forget other uterine diseases as a potential cause of infertility. CEH may occur following the use of progestins [START_REF] Chatdarong | Hysterographic appearance and uterine histology at different stages of the reproductive cycle and after progestagen treatment in the domestic cat[END_REF], or in queens getting older and/or having presented several episodes of spontaneous ovulations, with subsequent progesterone secretion leading to endometrial development without pregnancy [START_REF] Axnér | Clinical approach to conditions of the non-pregnant and neutered queen[END_REF]. It may of course be a cause of infertility due to the incapacity of embryos to survive in such a hostile environment. Nowadays, the diagnosis of CEH is easily done by ultrasound, but as in bitches, the uterine changings are irreversible; there is no standardized treatment.

Hydrometra and mucometra

Finally, hydrometra or mucometra is sometimes found in infertile young queens without any clinical sign. Very often, the exact cause is impossible to determine and there is no standardized treatment [START_REF] Verstegen | Mucometra, cystic endometrial hyperplasia, and pyometra in the bitch: advances in treatment and assessment of future reproductive success[END_REF].

Infectious diseases: a high risk in breeding facilities?

Infectious diseases caused by viruses or bacteria may lead to pregnancy arrest, neonatal diseases or loss of kittens. Cat shows increase the risk of infections. A study conducted in Sweden has shown that, when coming back from a show, 10.4 % of breeders reported conjunctivitis in some of their cats, and 14.6% reported upper respiratory tract diseases [START_REF] Holst | The Swedish breeding cat: population description, infectious diseases and reproductive performance evaluated by a questionnaire[END_REF].

The role of cat shows for the development of reproductive problems in cateries has not been studied but cannot be excluded.

There are few recent reviews about the role of infectious agents towards feline infertility [START_REF] Decaro | Viral reproductive pathogens of dogs and cats[END_REF][START_REF] Graham | Bacterial Reproductive Pathogens of Cats and Dogs[END_REF][START_REF] Lamm | Clinical Approach to Abortion, Stillbirth, and Neonatal Death in Dogs and Cats[END_REF]. These agents may prevent implantation and/or embryonic development or induce pregnancy loss, which may remain unnoticed if the embryos are resorbed in utero and therefore appear as "infertility".

Viruses

Among viral diseases, only retroviruses (FeLV, FIV) and the parvovirus have been confirmed as "aborting" agents. The role of Feline Herpesvirus (FHV) or Calicivirus remains unclear; more studies should be performed as these two diseases are a major concern in cateries. After an experimental inoculation with FHV a pregnancy loss occurred in one study [START_REF] Hoover | Experimental feline herpesvirus infection in the pregnant cat[END_REF]. However, its exact role effect on fertility in catteries is still unclear and controversial. Resorption or abortion due to Calicivirus may occur in unvaccinated queens, due to fetal contamination [START_REF] Van Vuuren | Characterisation of a potentially abortigenic strain of feline calicivirus isolated from a domestic cat[END_REF], and there is no full protection from vaccination. Furthermore, asymptomatic carriers exist. Feline Coronavirus is considered as an uncommon cause of reproductive problems [START_REF] Holst | Disease Transmission by Mating or Artificial Insemination in the Cat : Concerns[END_REF].

Bacteria

Chlamydophila felis was mentioned as possible cause for abortions and was isolated in cases of reproductive disorders concurrent with upper respiratory tract disease; however, its role as a cause for infertility is still unclear. However, for some authors, there is circumstantial evidence that C. felis may cause abortion [START_REF] Gruffydd-Jones | Chlamydophila felis infection. ABCD guidelines on prevention and management[END_REF]. One publication reports about the potential role of Chlamydia psittaci, stating however that in cats with reproductive disorders and upper respiratory tract disease, FHV was more often isolated than Chlamydia psittaci [START_REF] Sykes | Prevalence of feline Chlamydia psittaci and feline herpesvirus 1 in cats with upper respiratory tract disease[END_REF]. Further causes of infertility might be Coxiella burnetii [START_REF] Shapiro | Seroprevalence of Coxiella burnetii in domesticated and feral cats in eastern Australia[END_REF] Leptospira sp. or Bartonella henselae [START_REF] Guptill | Evidence of reproductive failure and lack of perinatal transmission of Bartonella henselae in experimentally, infected cats[END_REF]. In one report, Brucella spp. and Brucella abortus were mentioned as possible causative organisms for pyometra in queens. [START_REF] Wareth | Isolation of Brucella abortus from a Dog and a Cat Confirms their Biological Role in Re-emergence and Dissemination of Bovine Brucellosis on Dairy Farms[END_REF].

As in bitches, the role of the imbalance of the vaginal flora is probably under-estimated, and especially the potential pathogenic role of E.coli [START_REF] Lawler | Histopathologic features, environmental factors, and serum estrogen, progesterone, and prolactin values associated with ovarian phase and inflammatory uterine disease in cats[END_REF]. As already said earlier, it may be a potential cause of endometritis and pregnancy arrest. But very few studies have been done on the genital flora in cats [START_REF] Clemetson | Bacterial flora of the vagina and uterus of healthy cats[END_REF] and pure growth of bacteria within the vagina seems to be a normal finding in many queens without any reproductive failure [START_REF] Holst | Characterization of the bacterial population of the genital tract of adult cats[END_REF].

Parasites

Cat reproduction may also be impaired by parasitic infection. There is a special concern about Toxoplama gondii, because cats are both definitive and intermediate hosts, although the reproductive tract is not commonly affected [START_REF] Hartmann | Toxoplasma Gondii Infection in Cats: ABCD guidelines on prevention and management[END_REF]. Experimentally induced trans-placental contamination and even abortion may occur [START_REF] Sakamoto | Experimental infection of pregnant queens with two major Brazilian clonal lineages of Toxoplasma gondii[END_REF]. If a pregnant queen is seronegative, it may therefore be recommended to avoid her hunting and eating raw meat. Cytauxzoon felis, a ticktransmitted protozoal parasite has also been mentioned in a case report [START_REF] Weisman | Blood smear from a pregnant cat that died shortly after partial abortion[END_REF].

Bad semen quality in purebred male cats?

Pet animal males, opposed to farm animals, are selected for breeding mostly on the basis of their appearance and behaviour, not reproductive traits. This may lead to various fertility problems and lower semen quality in pedigree individuals. Although there are numerous studies describing semen quality and sperm characteristics in cats, they were performed mostly on Domestic Shorthair cats and data regarding semen quality in purebred cats are very scarce.

There are very few data regarding the relation between breeds and fertility. Axner et al. 1996 described 10 cases of infertile tomcats of different breeds (Cornish Rex, Burmese, Siamese, Persian, Ragdoll, domestic shorthair) and in 4/10 cases the cause of infertility was bad semen quality -azoospermia and teratozoospermia [START_REF] Axnér | Reproductive disorders in 10 domestic male cats[END_REF]. The department of Reproduction in Wrocław (Poland) has registered nine tomcats presented for infertility (unpublished data).

They were of different breeds (Sphynx, Main coon, Bengal, Ragdoll, Siberian Forest Cat) and from different catteries. In three cases the diagnosis was severe oligospermia and teratozoospermia, in two cases -teratozoospermia with normal total sperm count, in three cases -sperm DNA damage. Regarding these data, it seems that azoospermia/oligospermia and teratozoospermia often cause fertility problems in pedigree cats.

Teratozoospermia

Teratozoospermia is a common phenomenon in felids (both wild and domestic cat) [START_REF] Pukazhenthi | The impact and potential etiology of teratospermia in the domestic cat and its wild relatives[END_REF]. The threshold for teratozoospermia in cats has been established at less than 40% of normal spermatozoa in the sample [START_REF] Howard | Teratospermia in Domestic Cats Compromises Penetration of Zona-Free Hamster Ova and Cat Zonae Pellucidae[END_REF].

One study showed that teratozoospermic spermatozoa possessed worse motility parameters, compromised ability to capacitate and undergo the acrosome reaction, abnormal chromatin integrity and lower expression of phospholipase C Zeta [START_REF] Prochowska | Characteristics of urethral and epididymal semen collected from domestic cats--A retrospective study of 214 cases[END_REF]. Importantly, even apparently normal spermatozoa from teratozoospermic males were impaired [START_REF] Howard | Teratospermia in Domestic Cats Compromises Penetration of Zona-Free Hamster Ova and Cat Zonae Pellucidae[END_REF].

In none of these studies in vivo fertility was evaluated and it is known that teratozoospermic tomcats can be fertile. In one study [START_REF] Axnér | Sperm morphology in the domestic cat, and its relation with fertility: a retrospective study[END_REF], 11 teratozoospermic cats with known breeding records were all fertile. Unpublished data from our laboratory showed that 6 out of 20 ejaculates from ten fertile pedigree cats (four cats collected more than once) were classified as teratozoospermic.

When considering teratozoospermia in cats, one important fact has to be emphasized: in cats there are two different types of teratozoospermia, of different origins and differently affecting spermatogenic parameters [START_REF] Jewgenow | Analysis of Sertoli cell efficiency allows the differentiation between two fundamentally different forms of feline teratospermia[END_REF], although no cut-off value has been established so far. The first type, which can be named 'persistent', is a permanent feature of a particular tomcatsuch male consistently produces spermatozoa of poor morphology. This type is connected to several alterations of spermatogenesis: fewer Sertoli cells per tubule with increased number of round spermatids (increased Sertoli cell efficiency [START_REF] Neubauer | Quantity rather than quality in teratospermic males: a histomorphometric and flow cytometric evaluation of spermatogenesis in the domestic cat (Felis catus)[END_REF], accompanied by reduced germ cell apoptosis [START_REF] Jewgenow | Reduced germ cell apoptosis during spermatogenesis in the teratospermic domestic cat[END_REF], which leads to higher sperm output -a phenomenon called "quantity rather than quality" [START_REF] Neubauer | Quantity rather than quality in teratospermic males: a histomorphometric and flow cytometric evaluation of spermatogenesis in the domestic cat (Felis catus)[END_REF]. This type of teratozoospermia is linked to reduced heterozygosity and can be found in highly inbred rare wild felids (e.g. Florida panthers, clouded leopards and cheetahs) and can be established experimentally via incestuous breeding [START_REF] Pukazhenthi | The impact and potential etiology of teratospermia in the domestic cat and its wild relatives[END_REF].

The other type of teratozoospermia, which can be named 'random', is found in tomcats that present normal quantitative spermatogenic parameters and may be a transient worsening of semen quality. The etiology of this type of teratozoospermia is unknown. Some studies comparing normo-and teratozoospermic cats suggest that potential factors may include: hormonal imbalance in the testes [START_REF] Müller | Testicular testosterone: estradiol ratio in domestic cats and its relationship to spermatogenesis and epididymal sperm morphology[END_REF], diet and stress [START_REF] Swanson | Reproductive status of endemic felid species in Latin American zoos and implications for ex situ conservation[END_REF], age and season [START_REF] Axnér | Sperm morphology in the domestic cat, and its relation with fertility: a retrospective study[END_REF]. This list remains open and more studies are required to understand the causes of 'random' teratozoospermia and its connection to fertility.

As purebred cats may present higher homozygosity, higher incidence of teratozoospermia can be expected. Indeed, in one study [START_REF] Axnér | Sperm morphology in the domestic cat, and its relation with fertility: a retrospective study[END_REF] Pedigree cats had a lower mean percentage of normal spermatozoa than did household cats.

Azoospermia

Azoospermia is defined as a lack of spermatozoa in the semen sample. In the case of azoospermia it is crucial to exclude 'false' azoospermia, which means unsuccessful collection of spermatozoa -spermatozoa are produced in the testes but for some reasons they were not expelled into the ejaculate. The potential causes include: retrograde ejaculation [START_REF] Axnér | Reproductive disorders in 10 domestic male cats[END_REF], blockage or abnormalities of ductus deference (obstructive azoospermia), or failure of the collection method. The two most commonly used methods (electroejaculation and urethral catheterization) are characterised by high efficacy (more than 90% success), nevertheless, in the case of no spermatozoa in the sample the authors always recommend a second attempt of collection after several days to avoid a false diagnosis. Sometimes the changing of a collection method is helpful (personal observations).

True azoospermia can be observed e.g. in cases of chromosomal abnormalities or testicular hypoplasia and degeneration [START_REF] Johnston | Ovarian and testicular function in the domestic cat: Clinical management of spontaneous reproductive disease[END_REF]. As spermatogenesis is directed by testosterone, hormonal background of azoospermia/oligozoospermia may be considered.

To differentiate 'true' and 'false' azoospermia, alkaline phosphatase (AP) can be measured in the sample. It is an enzyme produced in the testis and epididymis [START_REF] Johnston | Ovarian and testicular function in the domestic cat: Clinical management of spontaneous reproductive disease[END_REF], therefore in a normal ejaculate its concentration in seminal plasma is high (>20 000 UI/l [START_REF] Valiente | Ejaculation training, seminal alkaline phosphatase and semen preservation through cooling in a milk-based extender in domestic cats[END_REF], or even 160 000 UI/l [START_REF] Johnston | Ovarian and testicular function in the domestic cat: Clinical management of spontaneous reproductive disease[END_REF]. To the best of our knowledge, no cut off value has been determined for tomcats. In the case of an unsuccessful collection, its concentration is low.

In human medicine testicular biopsy is a common diagnostic procedure, helpful in differentiating different disturbances of spermatogenesis (e.g. Sertoli cell only syndrome, maturation arrest, hypospermatogenesis [START_REF] Cerilli | A practical approach to testicular biopsy interpretation for male infertility[END_REF]. There are some publications describing this procedure in cats [START_REF] Leme | Testicular cytology by fine needle aspiration in domestic cats[END_REF].

Endocrine disturbances

Endocrine disturbances are also often stated as a potential cause of infertility.Hyperoestrogenism may exert a negative effect on reproduction. It may happen in the case of follicular cysts, reported to be common in the cat [START_REF] Johnston | Canine and feline theriogenology[END_REF] or granulosa cell tumours. Some queens, frequently Orientals or Siameses (personal observations), show abnormally frequent oestruses, so close to each other that the successive follicular waves overlap, creating prolonged heats [START_REF] Axnér | Clinical approach to conditions of the non-pregnant and neutered queen[END_REF]. Such abnormal cycles have to be diagnosed and treated without delay, as they may lead to further development of a pyometra or a non-regenerative anaemia due to bone marrow toxicity of oestrogens (personal observations). Hypoluteoidism or lack of progesterone to maintain the pregnancy has been suspected to occur occasionally in the queen [START_REF] Verstegen | Canine and feline pregnancy loss due to viral and non-infectious causes: a review[END_REF], although not confirmed. In a survey, Maine Coon was the most frequent breed to be cited by veterinarians as potentially suspected to suffer from hypoluteoidism [START_REF] Fontbonne | Potential causses of infertility in purebred cats: a survey of data collected from different countries[END_REF].

Nutrition

Nutrition may have an effect on reproductive performances. Essential nutrients such as taurine, arachidonic acid and the supply of poly-unsaturated fatty acids (PUFAs) and copper have to be provided in the cat food. Some studies have demonstrated the impact of nutrition on semen quality in Felids [START_REF] Howard | Nutritional Factors Affecting Semen Quality in Felids[END_REF][START_REF] Paz | Influence of nutrition on the quality of semen in Jaguars Panthera onca in Brazilian zoos[END_REF]. Due to the growing interest of purebred cat breeders for raw-food diets, attention is drawn to the microbiological content of it, as bacteria exerting potential bad effects on reproduction and general health (Salmonella spp., Campylobacter spp., Listeria spp., E.coli…) may sometimes be isolated if the conservation of the food has not be done correctly [START_REF] Davies | Raw diets for dogs and cats: a review, with particular reference to microbiological hazards[END_REF] . A recent publication [START_REF] Singh | A comparison of mycotoxin contamination of premium and grocery brands of pelleted cat food in South Africa[END_REF] found also a high content of mycotoxins in pelleted cat food in South Africa. An evaluation of diseases, including reproductive problems, affecting dogs and cats and their relationship to pet food mycotoxin contamination was reported in Brazil [START_REF] De Souza | 07ea2035435eae9acb342[END_REF].

Chromosomical or genetical problems

Chromosomical or genetical problems are not uncommon in cats. Abnormal chromosomic formulas may be found, such as a monosomy 37X0, trisomies (39 XXY, 39XXX, 39XYY) chimerism or mosaicism [START_REF] Szczerbal | Disorders of sex development in cats with different complements of sex chromosomes[END_REF]. This may lead to primary anoestrus or to infertility in females that seem to cycle normally, or to abortion of foetuses with an abnormal karyotype. In male cats, attention has to be drawn to the special case of tortoiseshell male cats who often suffer from the Klinefelter syndrome (39 XXY) and present azoospermia [START_REF] Moran | Fertile male tortoiseshell cats: Mosaicism due to gene instability?[END_REF].

Inbreeding -an often cited cause of low reproductive performances -appears uncommon in Pedigree cats. A study among Polish purebred cats [START_REF] Mucha | Inbreeding rate and genetic structure of cat populations in Poland[END_REF] evaluated the degree of inbreeding at around 3%. Only Siberian cats were slightly more inbred (more than 5%). In France, [START_REF] Leroy | An insight into population structure and gene flow within pure-bred cats[END_REF] [START_REF] Leroy | An insight into population structure and gene flow within pure-bred cats[END_REF] found an average degree of inbreeding of 5% (except in Devon Rex in which it was higher). The rather low degree of inbreeding may be due to the fact the large majority of breeders are occasional ones and use their reproducers with moderation. In Sweden 58% of purebred cats breeders use their own male [START_REF] Holst | The Swedish breeding cat: population description, infectious diseases and reproductive performance evaluated by a questionnaire[END_REF]. It is even more frequent in France where 93.3% of breeders use their own tom cat [START_REF] Fournier | Epidemiological analysis of reproductive performances and kitten mortality rates in 5,303 purebred queens of 45 different breeds and 28,065 kittens in France[END_REF].

Miscellaneous.

9.1 Delayed puberty, also called primary anoestrus, may be due to different causes. Lack of social contact with other cats, low luminosity within the breeding facility, a body weight below 2.3 kg (except in giant breeds) or excessive stress may play a role in postponing puberty. [START_REF] Romagnoli | Fertility parameters and reproductive management of Norwegian Forest Cats, Maine Coon, Persian and Bengal cats raised in Italy: a questionnaire-based study[END_REF] [START_REF] Romagnoli | Fertility parameters and reproductive management of Norwegian Forest Cats, Maine Coon, Persian and Bengal cats raised in Italy: a questionnaire-based study[END_REF] found that, in Italy, the season in which a queen was born, did not influence the age of her puberty; even though females reaching full body weight in winter often show delayed puberty [START_REF] Johnston | Canine and feline theriogenology[END_REF]. There may be differences linked with the latitude of the country, southern cats living under stronger light stimulations, or to the fact that nowadays, most breeding facilities occur in better lit facilities. Anatomical malformations or intersexual state, often linked with a chromosomical defect, may be diagnosed during a clinical examination. In such a case, it may be interesting to ask for a karyotype in a competent laboratory. Veterinarians should also ask the owners if the young queen has not been treated with progestins or antifungic drugs -often used to treat ringworm in catteriesthat may interfere with the normal hormonal balance at puberty. They should also be aware of queens which have already been spayed, as early neutering is more and more frequently performed before the sale of kittens, to avoid further reproduction. Luteinizing hormone (LH) [START_REF] Rohlertz | Comparison of the GnRH-stimulation test and a semiquantitative quick test for LH to diagnose presence of ovaries in the female domestic cat[END_REF] and/or Anti-Müllerian hormone (AMH) assays [START_REF] Axnér | Concentrations of anti-Müllerian hormone in the domestic cat. Relation with spay or neuter status and serum estradiol[END_REF] may help diagnosing the absence of ovaries in a queen presenting a delayed puberty. In the near future, assaying AMH may also help to detect if a queen is still at a pre-pubertal stage [START_REF] Flock | Changes in anti-Müllerian hormone concentrations in queens throughout the oestrous cycle. 22nd EVSSAR Congr[END_REF]. 9.2 Secondary anoestrus or abnormally prolonged interoestrus, in a queen that was cycled before, may be due to several factors, including the season of the year. Romagnoli et al.

(2019) studied the distribution of the oestrus cycles in 128 queens from 4 different breeds and found important differences, only 20% of the queens being cycled in November versus more than 70% in March or April [START_REF] Romagnoli | Fertility parameters and reproductive management of Norwegian Forest Cats, Maine Coon, Persian and Bengal cats raised in Italy: a questionnaire-based study[END_REF]. There are also differences in relation to the breed, as a study in UK found that a non-breeding season existed for 90% of long-haired cats (Persians, other long-haired) versus 39.2% of short-haired cats [START_REF] Jemmett | A survey of sexual behaviour and reproduction of female cats[END_REF]. Vaginal smears are the first step to confirm an anoestrus state, and to differentiate it from cases where the queen is cycled but not presenting any clinical oestrus. In such a case the smear will contain some degree of keratinized superficial cells. This may happen in case of "silent heats" -oestruses without any clinical signs such as crying, lordosis or searching for the male -which seem to be more frequent in Maine Coons and Persians [START_REF] Fontbonne | Potential causses of infertility in purebred cats: a survey of data collected from different countries[END_REF]. It may also be due to progesterone secretion down-regulating the hypothalamo-pituitary axis, in case of a pseudo-pregnancy, or ovarian luteinized cysts or ovarian tumours. Progesterone assays, together with ovarian and uterine ultrasonography, may help the diagnostic. An induction of oestrus may be tempted only in a confirmed anoestrus state, with basal progesteronemia or inactive ovaries under ultrasound. 9.3 Environmental pollutants, such as bisphenol A, should also be mentioned, as they are more and more often cited as negative agents on reproductive processes in humans. Bisphenol A has been recently demonstrated to have a suppressive effect on uterine contractions in queens that may lead to infertility [START_REF] Kabakci | Inhibitory effect of Bisphenol A on in vitro feline uterine contractions[END_REF].

In conclusion, although there is much less published data about cat infertility than there is for dogs, it appears that some potentially predominant causes deserve some dedicated research.

Among them, uterine problems in females and teratospermia in males have to be more deeply studied, in order to understand these factors, to better diagnose them and to develop treatments that may restore a normal fertility in subfertile or infertile purebred cats.

Acknowledgements

The authors wish to thank Dr Achraf Adib-Lesaux and Dr Claire Mariani from Royal Canin company for their scientific collaboration and support, Mrs Felicity Leith-Ross for her great help in improving the English language, and all their colleagues of the CERCA (Centre d'Etude en Reproduction des Carnivores).

Conflict of interest

The authors have no conflict of interest to declare.

Funding

The authors received no financial support for publication of this article.

Ethical approval This work did not involve the use of animals and therefore ethical approval was not required.

Informed consent This work did not involve the use of animals and therefore informed consent was not required.

Informed consent for publications

No animals or humans are identifiable within this publication, and therefore additional Informed Consent for publication was not required.


Guillaume Couture
email: guillaumecouturecouture.g@chu-toulouse.fr

Michel Laroche

Amélioration des atteintes osseuses d' une hyperparathyroïdie secondaire post parathyroidiectomie

niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Amélioration des atteintes osseuses de l'hyperparathyroïdie secondaire post parathyroidiectomie

Guillaume Couture 1 ; Michel Laroche 1 1 : Service de rhumatologue, CHU de Toulouse, hôpital Pierre-Paul-Riquet, 1, place du Dr-Baylac, 31059 Toulouse cedex, France


W Hu

A Trimaille

N Kerfant

A-S Henry

P Ta

Rouanet

D Le Nen

E Stindel

S Ansart

Multidisciplinary management of the bone and joint infection complicating treatment of an open fracture of the lower limb

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Les infections ostéo-articulaires (IOA) regroupent toutes les infections musculosquelettiques touchant à l'os et/ou aux articulations.

Leur traitement est complexe, et repose sur un gold standard associant un débridement agressif, une stabilisation osseuse, une couverture de la zone d'exposition, ainsi qu'un traitement antibiotique adapté [START_REF] Mouzopoulos | Management of bone infections in adults: the surgeon's and microbiologist's perspectives[END_REF][START_REF] Arnold | Muscle flaps in osteomyelitis of the lower extremity: a 20-year account[END_REF][START_REF] Malizos | Ankle and foot osteomyelitis: Treatment protocol and clinical results[END_REF][START_REF] Harris | Staphylococci and implant surfaces: a review[END_REF]. En l'absence d'une prise en charge adéquate, ces infections peuvent entraîner des séquelles fonctionnelles importantes et dans certains cas engager le pronostic vital du patient [5,[START_REF]collège des universitaires de maladies infectieuses et tropicales C. E. PILLY[END_REF].

Actuellement, en France, la planification de cette prise en charge est transversale. Elle s'effectue au cours des réunions de concertation pluridisciplinaire (RCP) mises en place au sein des centres inter-régionaux experts et des centres correspondants qui regroupent les compétences de différentes spécialités dont, nécessairement, un chirurgien orthopédique, un infectiologue et un microbiologiste [START_REF]Lettre DHOS E2/73 du 13 juin 2008 sur la reconnaissance interrégionale de centres de référence pour la prise en charge des infections ostéo-articulaires[END_REF]. La présence d'un chirurgien plasticien, même si elle n'est pas exigée, nous semble nécessaire du fait de notre expérience, afin d'établir une stratégie médicochirurgicale des plus adaptées, et de limiter le risque important de rechute.

Particularités des infections compliquant une fracture ouverte

Quelle Prévalence ?

Dans le cadre des fractures ouvertes du membre inférieur, le taux d'infection est important, variant de 3 à 40 % des cas selon les auteurs [START_REF] Mouzopoulos | Management of bone infections in adults: the surgeon's and microbiologist's perspectives[END_REF][START_REF] Harris | Staphylococci and implant surfaces: a review[END_REF][START_REF] Carsenti-Etesse | Epidemiology of bacterial infection during management of open leg fractures[END_REF]. Ce taux est corrélé à l'importance de l'ouverture cutanée. Cela s'explique par le mécanisme du traumatisme. En effet, le mode de contamination bactérienne est alors direct de dehors en dedans, dans les suites de l'effraction cutanée. En outre, les fractures Cauchoix 2 et 3 sont souvent secondaires à des traumatismes à haute cinétique responsables d'une contusion tissulaire importante. La nécrose tissulaire peut ensuite s'étendre aux tissus adjacents dans les jours suivants le traumatisme (Fig. 1). Il s'agit du concept de « zone of injury » [START_REF] Georgescu | Emergency free flaps[END_REF][START_REF] Bellidenty | Reconstruction des pertes de substance de membres inférieurs par lambeau libre en urgence. À propos de 35ans d'expérience[END_REF] .

Quels germes incriminés ?

Dans le cas des infections ostéoarticulaires, toutes étiologies confondues, les germes retrouvés dans la majorité des cas sont des cocci Gram positifs avec une grande proportion de staphylococcus aureus, viennent ensuite par ordre de fréquence les streptocoques et les germes anaérobies [START_REF] Malizos | Ankle and foot osteomyelitis: Treatment protocol and clinical results[END_REF]5,[START_REF] Lecuire | Ten-year surveillance of nosocomial surgical site infections in an orthopedic surgery department[END_REF][START_REF] Debarge | Surgical site infection after total knee arthroplasty: a monocenter analysis of 923 first-intention implantations[END_REF][START_REF] Phillips | The incidence of deep prosthetic infections in a specialist orthopaedic hospital: a 15-year prospective survey[END_REF][START_REF] Bauer | Impact of a multidisciplinary staff meeting on the quality of antibiotherapy prescription for bone and joint infections in orthopedic surgery[END_REF].

Dans la littérature, on retrouve une proportion plus importante de bacille Gram négatif (BGN) dans les IOA survenant après fracture ouverte en comparaison avec les IOA survenant après arthroplastie [START_REF] Faisham | Bacteriological study and its role in the management of open tibial fracture[END_REF]. Cela s'explique par l'utilisation d'une antibiothérapie systématique administrée lors de la prise en charge des fractures ouvertes au stade initial, favorisant ainsi l'émergence des BGN [START_REF] Carsenti-Etesse | Epidemiology of bacterial infection during management of open leg fractures[END_REF][START_REF] Burns | Microbiology and injury characteristics in severe open tibia fractures from combat[END_REF].

Quand évoquer une infection ostéoarticulaire ?

Il faut évoquer une IOA devant l'apparition de signes cliniques locaux avec présence d'abcès, fistule, douleur, inflammation cicatricielle et/ou signes cliniques généraux avec fièvre et frisson (Fig. 2) [5,[START_REF]collège des universitaires de maladies infectieuses et tropicales C. E. PILLY[END_REF]17]. Les infections aiguës sont définies par l'apparition de ces signes dans

Quelle antibiothérapie ?

Les experts recommandent de débuter une antibiothérapie probabiliste, après réalisation des prélèvements microbiologiques, en utilisant des molécules ayant une bonne diffusion osseuse. Elle est administrée initialement en bithérapie par voie intraveineuse [5,[START_REF]collège des universitaires de maladies infectieuses et tropicales C. E. PILLY[END_REF]17].

Elle sera adaptée secondairement en fonction des résultats bactériologiques. Le relai oral, s'il est possible, est préconisé après J15. La durée minimale du traitement est de 6 semaines.

Les durées usuelles dans la littérature varient de 6 à 12 semaines en fonction de la présence, ou non, de matériel d'ostéosynthèse.

Prise en charge chirurgicale

Le débridement chirurgical

Un parage agressif est nécessaire (Fig. 3). Il permet d'éliminer l'ensemble des tissus cutanés, sous cutanés non vascularisés ainsi que les séquestres osseux, et est associé à un lavage abondant. L'objectif étant de diminuer l'inoculum bactérien [START_REF] Harris | Staphylococci and implant surfaces: a review[END_REF]5,[START_REF] Georgescu | Emergency free flaps[END_REF][START_REF] Salgado | Muscle versus nonmuscle flaps in the reconstruction of chronic osteomyelitis defects[END_REF][START_REF] Akm | One-stage treatment of chronic osteomyelitis of the proximal tibia using a pedicled vascularised double-barrel fibular flap together with a muscle flap[END_REF][START_REF] Föhn | Single step fibula-pro-tibia transfer and soft tissue coverage with free myocutaneous latissimus dorsi flap after extensive osteomyelitis and soft tissue necrosis -a 3 year follow up[END_REF][START_REF] Cierny | Surgical Treatment of Osteomyelitis[END_REF][START_REF] Tajsiς | Sural perforator flap for reconstructive surgery in the lower leg and the foot: a clinical study of 86 patients with post-traumatic osteomyelitis[END_REF][START_REF] Asko-Seljavaara | Management of infected fractures of the tibia with associated soft tissue loss: experience with external fixation, bone grafting and soft tissue reconstruction using pedicle muscle flaps or microvascular composite tissue grafts[END_REF][START_REF] Gokalp | Results of treatment of chronic osteomyelitis by "gutter procedure and muscle flap transposition operation[END_REF][START_REF] Smith | The treatment of chronic osteomyelitis: A 10 year audit[END_REF][START_REF] Park | Treatment of chronic osteomyelitis using the medial sural perforator flap[END_REF][START_REF] Hong | The use of anterolateral thigh perforator flaps in chronic osteomyelitis of the lower extremity[END_REF][START_REF] Rao | Treating Osteomyelitis: Antibiotics and Surgery[END_REF].

En présence de matériel d'ostéosynthèse, l'existence d'un biofilm (adhésion microbienne sur les surfaces métalliques) rend inefficace le lavage chirurgical tardif. Ainsi, au-delà de 3 semaines post ostéosynthèse, et selon l'état de consolidation osseuse, il convient de procéder soit à la dépose, soit au changement du matériel contaminé [17,[START_REF] Rao | Treating Osteomyelitis: Antibiotics and Surgery[END_REF].

La stabilisation osseuse

Le choix de l'ostéosynthèse doit conduire à l'obtention d'un montage solide, extra focal, ne compromettant ni la réalisation d'un lambeau de couverture ni une rééducation post opératoire (Fig. 4). Ainsi la mise en place d'un fixateur externe en un seul plan de fixation estelle recommandée [START_REF] Mouzopoulos | Management of bone infections in adults: the surgeon's and microbiologist's perspectives[END_REF]17,[START_REF] Cierny | Surgical Treatment of Osteomyelitis[END_REF][START_REF] Tajsiς | Sural perforator flap for reconstructive surgery in the lower leg and the foot: a clinical study of 86 patients with post-traumatic osteomyelitis[END_REF][START_REF] Asko-Seljavaara | Management of infected fractures of the tibia with associated soft tissue loss: experience with external fixation, bone grafting and soft tissue reconstruction using pedicle muscle flaps or microvascular composite tissue grafts[END_REF][START_REF] Park | Treatment of chronic osteomyelitis using the medial sural perforator flap[END_REF][START_REF] Hong | The use of anterolateral thigh perforator flaps in chronic osteomyelitis of the lower extremity[END_REF][START_REF] Fodor | The Distally Based Sural Musculoneurocutaneous Flap for Treatment of Distal Tibial Osteomyelitis[END_REF][START_REF] Erdinger | Osteomuscular latissimus dorsi scapula flap to repair chronic, posttraumatic osteomyelitis of the lower leg[END_REF][START_REF] Chim | Free Tissue Transfer with Distraction Osteogenesis Is Effective for Limb Salvage of the Infected Traumatized Lower Extremity[END_REF]. L'ostéosynthèse interne première, par vis plaque ou enclouage, n'est pas à privilégier en raison de la présence d'un biofilm qui risque d'entretenir le sepsis [START_REF] Harris | Staphylococci and implant surfaces: a review[END_REF]5,[START_REF] Carsenti-Etesse | Epidemiology of bacterial infection during management of open leg fractures[END_REF].

La reconstruction osseuse

Le comblement de la perte de substance osseuse intervient lorsqu'il existe une cavité résiduelle après parage chirurgical ou existence d'une pseudarthrose.

Plusieurs techniques sont décrites au sujet de comblements, non ostéogéniques (ciment imprégné d'antibiotique) et ostéogéniques (greffe osseuse/cortico-spongieuse locale, locorégionale ou microvascularisée) [17]. Le choix de la technique de Masquelet permet d'associer ces deux solutions et de diminuer le risque d'échec. Ainsi, la perte de substance est-elle comblée par du ciment avec antibiotique dans le même temps opératoire que le parage chirurgical (Figure 5). La greffe osseuse est réalisée 4 à 6 semaines plus tard, sous antibiothérapie adaptée en prenant soin de préserver la membrane vascularisée formée [START_REF] Masquelet | Bone Repair Using the Masquelet Technique[END_REF].

La couverture

Quel type de lambeau ?

Le choix du type de lambeau, dans le cadre du traitement des infections ostéoarticulaires du membre inférieur, fait toujours débat dans la littérature [START_REF] Salgado | Muscle versus nonmuscle flaps in the reconstruction of chronic osteomyelitis defects[END_REF][START_REF] Calderon | Comparison of the effect of bacterial inoculation in musculocutaneous and fasciocutaneous flaps[END_REF][START_REF] Hallock | Utility of both muscle and fascia flaps in severe lower extremity trauma[END_REF][START_REF] Yazar | Outcome Comparison between Free Muscle and Free Fasciocutaneous Flaps for Reconstruction of Distal Third and Ankle Traumatic Open Tibial Fractures[END_REF][START_REF] Moullot | Fractures ouvertes de la jambe et du pied: étude rétrospective comparative de la couverture par lambeau libre : latissimus dorsi versus anterolateral de cuisse[END_REF]. Il n'existe pas d'étude clinique comparative permettant d'établir une supériorité du lambeau musculaire sur le lambeau fascio-cutané en termes de guérison du sepsis ou de résultats fonctionnels obtenus. Cependant, des études rétrospectives réalisées dans le cadre de fractures ouvertes de la jambe ne permettent pas de mettre pas en évidence une différence significative dans l'apparition de complications à type d'IOA selon le type de lambeau utilisé [START_REF] Hallock | Utility of both muscle and fascia flaps in severe lower extremity trauma[END_REF][START_REF] Yazar | Outcome Comparison between Free Muscle and Free Fasciocutaneous Flaps for Reconstruction of Distal Third and Ankle Traumatic Open Tibial Fractures[END_REF][START_REF] Wagels | Soft tissue reconstruction after compound tibial fracture: 235 cases over 12 years[END_REF][START_REF] Danino | Is muscle the best coverage for leg Gustilo IIIb fractures? A retrospective comparative study[END_REF][START_REF] Kneser | Comparison between distally based peroneus brevis and sural flaps for reconstruction of foot, ankle and distal lower leg: An analysis of donor-site morbidity and clinical outcome[END_REF][START_REF] Wettstein | Review of 197 consecutive free flap reconstructions in the lower extremity[END_REF].

Selon notre expérience, le choix du type de lambeau repose essentiellement sur la taille et la localisation de la perte de substance à couvrir et sur le contexte clinique du patient. L'objectif étant d'obtenir une reconstruction fiable, fonctionnelle et esthétique tout en minimisant les séquelles du site donneur.

Les lambeaux musculaires présentent une grande fiabilité et une plasticité permettant le comblement des espaces morts, diminuant le risque d'hématome post opératoire, source de contamination bactérienne (Fig. 6 ; Fig. 7) [START_REF] Arnold | Muscle flaps in osteomyelitis of the lower extremity: a 20-year account[END_REF][START_REF] Salgado | Muscle versus nonmuscle flaps in the reconstruction of chronic osteomyelitis defects[END_REF][START_REF] Cierny | Surgical Treatment of Osteomyelitis[END_REF][START_REF] Asko-Seljavaara | Management of infected fractures of the tibia with associated soft tissue loss: experience with external fixation, bone grafting and soft tissue reconstruction using pedicle muscle flaps or microvascular composite tissue grafts[END_REF][START_REF] Gokalp | Results of treatment of chronic osteomyelitis by "gutter procedure and muscle flap transposition operation[END_REF][START_REF] Smith | The treatment of chronic osteomyelitis: A 10 year audit[END_REF][START_REF] Erdinger | Osteomuscular latissimus dorsi scapula flap to repair chronic, posttraumatic osteomyelitis of the lower leg[END_REF][START_REF] Calderon | Comparison of the effect of bacterial inoculation in musculocutaneous and fasciocutaneous flaps[END_REF][START_REF]Techniques chirurgicales-Chirurgie plastique reconstructrice et esthétique[END_REF][START_REF] Kawakatsu | Free latissimus dorsi musclocutaneous flap transfer for chronic osteomyelitis of the tibia: 16-year follow-up[END_REF][START_REF] Mathieu | Management of neglected open extremity fractures in low-resource settings: Experience of the French Army Medical Service in Chad[END_REF]. Ces avantages sont contrebalancés par une morbidité du site donneur sur le plan fonctionnel, comme le souligne Ismaïl et al dans l'utilisation du lambeau de grand dorsal, ainsi que par des séquelles esthétiques du site couvert [START_REF] Ismaïl | Sequelae after harvesting latissimus dorsi flap and derivates--review[END_REF].

Nous recourrons fréquemment aux lambeaux fascio-cutanés en raison d'un prélèvement rapide et peu invasif avec une vascularisation fiable sans sacrifice d'axe vasculaire majeur, et de la possibilité de réinnervation du lambeau sur le site de couverture [START_REF] Tajsiς | Sural perforator flap for reconstructive surgery in the lower leg and the foot: a clinical study of 86 patients with post-traumatic osteomyelitis[END_REF][START_REF] Hong | The use of anterolateral thigh perforator flaps in chronic osteomyelitis of the lower extremity[END_REF][START_REF]Techniques chirurgicales-Chirurgie plastique reconstructrice et esthétique[END_REF] (Fig. 8).

Les lambeaux perforants en hélice nous apportent une augmentation des possibilités de couvertures locales, dans des zones difficilement accessibles aux lambeaux musculaires pédiculés, comme le tiers inférieur de la jambe, la cheville ou le pied [START_REF] Tajsiς | Sural perforator flap for reconstructive surgery in the lower leg and the foot: a clinical study of 86 patients with post-traumatic osteomyelitis[END_REF][START_REF] Park | Treatment of chronic osteomyelitis using the medial sural perforator flap[END_REF][START_REF] Hong | The use of anterolateral thigh perforator flaps in chronic osteomyelitis of the lower extremity[END_REF][START_REF] Rubino | The propeller flap for chronic osteomyelitis of the lower extremities: a case report[END_REF] (Fig. 9). Cependant, dans le cadre des traumatismes à haute cinétique, une vigilance particulière sera nécessaire avant le recours à ces lambeaux perforateurs comme solution de couverture, en raison du risque important de contusion tissulaire des tissus adjacents à l'ouverture cutanée.

Quel délai ?

Bien qu'aucun consensus n'existe dans la littérature concernant le délai de couverture optimale d'une perte de substance dans le cadre des infections ostéoarticulaires, il est habituel de réaliser le lambeau de couverture après l'instauration d'une antibiothérapie efficace [START_REF] Mouzopoulos | Management of bone infections in adults: the surgeon's and microbiologist's perspectives[END_REF][START_REF] Malizos | Ankle and foot osteomyelitis: Treatment protocol and clinical results[END_REF][START_REF] Asko-Seljavaara | Management of infected fractures of the tibia with associated soft tissue loss: experience with external fixation, bone grafting and soft tissue reconstruction using pedicle muscle flaps or microvascular composite tissue grafts[END_REF][START_REF] Gravvanis | Blood perfusion of the free anterolateral thigh perforator flap: its beneficial effect in the reconstruction of infected wounds in the lower extremity[END_REF]. Dans notre pratique clinique, nous réalisons cette couverture entre la première et la deuxième semaine de traitement antibiotique.

Suivi des patients

Compte tenu de la complexité de la pathologie et du risque élevé de récidive, il nous semble important de réaliser un suivi rapproché au cours de l'année suivant la prise en charge d'une IOA. Pour notre part, ce suivi est assuré pour chaque patient, de manière pluridisciplinaire au cours de consultations conjointes en présence de chirurgiens orthopédistes et/ou plasticiens et de médecins infectiologues.

Conclusion

Une collaboration médicochirurgicale étroite est essentielle dans la prise en charge globale des infections ostéoarticulaires complexes du membre inférieur, et le chirurgien plasticien a toute sa place dans cette démarche. La réalisation systématique de prélèvement bactériologique en cas de suspicion clinique de sepsis, un parage agressif du site infecté, une stabilisation osseuse adéquate, une couverture rapide des pertes de substances cutanées après l'instauration d'une antibiothérapie ciblée ainsi que la mise en place d'un suivi médical et chirurgical adapté, sont, selon nous, indispensable à une prise en charge de qualité des infections ostéoarticulaires du membre inférieur compliquant une fracture ouverte.

Déclaration d'intérêts

Les auteurs déclarent ne pas avoir de conflits d'intérêts en relation avec cet article.

Légendes

les 6

 6 premiers mois du traumatisme initial tandis que les infections chroniques se définissent au-delà. Les signes biologiques sont marqués par une augmentation de la CRP, sa valeur peut cependant rester faible lors d' IOA chroniques. Les signes microbiologiques sont, eux, caractérisés par une positivité des prélèvements profonds de l'os et/ou des tissus mous. Enfin, les signes radiologiques sont définis par la présence de séquestres osseux, d'images d'ostéolyse ou de réaction périostée retardés de 15 à 21 jours par rapport au début de l'infection. Le recours à un scanner ou à une IRM est indiqué lors d'infections chroniques, l'analyse des images pouvant être perturbée par la présence d'artéfacts liée au matériel d'ostéosynthèse. Prise en charge médicale Comment réaliser les prélèvements bactériologiques ? Selon les recommandations des sociétés savantes, la réalisation des prélèvements bactériologiques doit avoir lieu dans de bonnes conditions, en per opératoire, en respectant les règles d'asepsie chirurgicale [5,6]. Ils doivent être réalisés à distance de toute antibiothérapie, idéalement avec un délai d'au moins 2 semaines entre l'arrêt du traitement et les prélèvements, afin de diminuer le risque de faux négatifs. Ces prélèvements bactériologiques s'effectuent en zone infectée, sous fascial, peuvent être liquides ou solides, et sont au nombre de 5. Le changement d'instrument entre chaque prélèvement est recommandé. Le recours à l'utilisation d'écouvillon est déconseillé.

Figure 1 :

 1 Figure 1 : Fracture ouverte Cauchoix 3 du quart distal de la jambe. Extension de la nécrose tissulaire en raison d'un parage insuffisant.

Figure 2 :

 2 Figure 2 : Ostéite chronique de la cheville dans les suites d'une fracture bimalléolaire ouverte Cauchoix 2 et arthrodèse tibio-talienne ; a. signes locaux ; b. ostéolyse.

Figure 3 :

 3 Figure 3 : Ostéite chronique en regard de la malléole interne. Parage.

Figure 4 :

 4 Figure 4 : Fracture ouverte Cauchoix 3 des deux os de la jambe. Stabilisation osseuse par fixateur externe en un seul plan.

Figure 5 :

 5 Figure 5 : Comblement osseux selon la technique de Masquelet ; a : perte de substance osseuse après parage ; b : comblement par du ciment ; c : couverture par un lambeau libre antérolatéral de cuisse.

Figure 6 :

 6 Figure 6 : Ostéite chronique du tiers inférieur de la jambe couvert par un lambeau hémi soléaire médial.

Figure 7 :

 7 Figure 7 : Couverture de la face antérieure du genou par un lambeau jumeau médial.

Figure 8 .

 8 Figure 8.a : fracture ouverte du quart distal de la jambe ; b levée d'un lambeau antéro-latéral de cuisse ; c : couverture de la perte de substance après stabilisation osseuse.

Figure 9 .

 9 Figure 9.a : fistule cutanée secondaire à une ostéo-arthrite de la patella ; b : couverture par un lambeau perforant en hélice ; c : résultat à 1 an.