TWISTED LIMBS IN KITTENS
In Feline Medical Curiosities I included a photo of a rescued kitten called Sophia (below) who was born with twisted hind legs and who was euthanised. I have received a number of emails from people who have also had kittens with twisted hind limbs and whose kittens have grown up to be normal adults. A number of these admonished me that Sophia was "needlessly put to sleep" and that her condition was curable, citing case histories of their own kittens. Other admonished me that cat workers "left it till too late" to treat her condition or that attempting treatment at all meant she was made to suffer.
Sophia was one of two moggy kittens taken in with a female stray; the family had come to the attention of cat workers when the normal kitten was seen playing outside a derelict shed. The malformed kitten was found inside the shed. The skin on the deformed kitten's hind legs had become ulcerated from being dragged about on the ground. Our vet was initially optimistic and wanted to give Sophia a chance. He splinted the least affected leg into a normal position and hoped to amputate the worst affected leg later. Sophia was put to sleep because her condition did not respond to treatment and she had internal abnormalities in addition to her twisted limbs. Sophia's entire hind end was failing to develop - her tail was short and tapered like that of a newborn and her bowel motions were jelly-like.
OCCURRENCE AND FREQUENCY OF TWISTED LIMB KITTENS
Numerous emails asking me for further information on twisted limb kittens have concerned stray or rescued cats and their kittens. It is easy to assume that the condition is linked to poor nutrition, poor welfare, disease or some genetic factor which has been bred out of purebreds.
However, as well as affecting moggies, twisted limbs have been noted in a wide range of breeds including Persians/Himalayans, Exotic Shorthairs, Korats, Bengals, Abyssinians/Somalis, British Shorthairs, American Shorthairs, Burmese, Siamese/Orientals and Turkish Vans. It is not limited to domestic cats and has apparently been noted in a captive-bred tiger cub where treatment was partially successful (the hind limbs apparently remaining weak). Twisted limbs have been reported in other domestic animals, in livestock and in zoo animals.
In cats, the condition is not geographically limited. Twisted limb kittens have been, and continue to be, reported around the world. As well as Sophia in the UK, cases have been reported in the USA, Canada, Australia, New Zealand, South Africa, Europe (including Eastern Europe), Hong Kong, Japan, Israel and the Middle East. Some of the photos here are of a case reported in 2003 in The Netherlands.
Sometimes more than one kitten in a litter is affected. Cat rescuer Beth reported that three out of four kittens born to her rescued feral cat were affected. The feral mother abandoned three kittens right after birth and they were taken in by Beth. The mother and the fourth kitten were found hidden in the hay barn two days later. Two of the three abandoned kittens had crooked hind limbs. The fourth kitten, i.e. the one not abandoned, also had crooked hind limbs. Beth's vet had not seen this condition previously and suggested leaving the kittens for a few weeks to see if the limbs straightened out of their own accord. At four days old, the kittens' legs can be moved into the correct position.
The occurrence of the condition in pedigree cats indicates that it is not restricted to poorly nourished cats. It was initially thought that Sophia's mother, a stray, had been poorly nourished and that this contributed to Sophia's condition e.g. insufficient calcium for proper bone growth. Sophia's sister was perfectly normal and the mother showed no depletion of calcium in her own bones. In addition, Sophia's forelimbs were robust rather than fragile. Oriental breeder Thom Bloks' vet suggests that a factor may be a particularly difficult birth and compression of the kitten into an unnatural position in the birth canal (dislocating the young and relatively soft limbs).
Many vets will never see a twisted limb kitten and are unfamiliar with the condition, thus when confronted with a twisted limb kitten, many vets immediately advise euthanasia. Most vets have believed the deformities to be permanent and not correctable. Some twisted-limb kittens, like Sophia, would have had had gross deformities combined with internal abnormalities so that euthanasia is the only humane option.
In October 2003, Rebecca Martin emailed about a case of twisted hind limbs in one of her kittens. A few years earlier, one of her female cats had a litter of kittens, one of which also had twisted back legs. The vet explained that it was probably caused in a stage of earlier development in the womb when another of the kittens had pushed against and bent back the leg. The kitten, along with one of his brothers, was rehomed to a friend of Rebecca's father, who later paid for surgery to have the deformity corrected. Following surgery, the kitten was apparently able to walk, run and jump normally.
Although the success in rehabilitating some kittens might suggest that others were needlessly euthanised, the actuality is that not all twisted limb kittens will grow out of the trait or be cured by surgery or splinting and physiotherapy. In Sophia's case, the entire hind end was affected, including her lower bowel. Just because some kittens are treatable, does not mean that all kittens can have the condition corrected. The converse is also true - just because Sophia was not treatable does not mean that all twisted limb kittens are untreatable. The earlier the condition is discovered, ideally at only a few days old, the better the chance of treatment being successful.
Some cat lovers have suggested that the legs of all afflicted kittens eventually straighten out and become perfectly normal. Caught early enough, the condition is treatable in many kittens. If only the legs are affected, there is a better chance of correcting the deformity. However, even with intensive treatment, not all kittens will recover and a cat owner must be prepared for that possibility. Cat rescuers and shelter workers are faced with an additional problem of time, resources and funding.
Both the front legs/paws and the hind legs/paws can be affected. Sometimes a single limb is affected (unilateral), sometimes (as with Sophia) the pair of limbs is affected (bilateral). Where pairs of limbs are affected, they may be equally affected or one may be more severely affected than the other. The severity varies e.g. paws curled under or sideways, limbs stiff and extended, hind limbs in the "Lotus" (yoga) position, hind limbs appearing to be put on backwards. Sophia had one "backwards" leg and one curled underneath her.
Except for Radial Hypoplasia (Twisty Cat condition) and related conditions, the cause of twisted limbs is developmental, not genetic. It appears to be due to the kitten's position in the womb, especially in a large litter where the womb is crowded. The developing kitten is cramped and its legs are placed awkwardly; there is no room to flex them and the tendons and ligaments become contracted from remaining in one position.
Another cause of malformed (or missing) limbs is umbilical strangulation of the limb - the umbilical cord becomes wrapped around the limb(s), restricting blood supply to those limbs. In these cases, the limb may be entirely missing though less severe cases may result in twisted or undersized limbs.
Although more than one kitten in a litter may be affected (particularly in large litters where the womb is overcrowded), there is no evidence that a mother cat will consistently produce twisted limb kittens in later litters. If she does continue to produce twisted limb kittens, there is a chance that she has an abnormal uterus which cramps the developing kittens or possibly a genetic cause e.g. affecting bone growth. In either case, spaying is recommended and (if possible) the sire's owner should be informed in case it is a recessive gene trait. To date, apart from the forelimb condition radial hypoplasia (below), twisted limbs have been shown to be developmental abnormalities not a hereditary condition.
Forelimb Twisting Due to Radial Hypoplasia (Twisty Cat)
If caught early, preferably at birth or within a day or two, there is a reasonable chance that the condition can be rectified with a combination of massage, physiotherapy (stretching/flexing the limb), warm compresses (to ease muscles which have locked into position) and by splinting (or more rarely pinning) the leg into the proper position.
The vet will also need to check that the kitten has feeling in the twisted limbs. The kitten may be unable to move them because the ligaments/tendons have contracted or the muscles are under-developed, locking the limb into one position. However, if the kitten cannot feel the limb, there may also be nerve or spinal damage. Spinal damage will also affect control of the tail and bowel/bladder function (only noticeable at an age when the kitten should be controlling these itself).
If the condition is treated early and the kitten is going to recover, an improvement is usually seen within days. If the limbs fail to respond to treatment and remain twisted and useless several weeks later despite regular physiotherapy/splinting, then the prognosis is poor. If only one limb is affected and the kitten is otherwise normal, amputation of the affected limb is a possibility. If the kitten shows other serious abnormalities, especially ones relating to the internal organs, then euthanasia is recommended as soon as those abnormalities become apparent.
One thing that is certain is that the longer the elapsed time between birth and treatment of a twisted limb, the less likely it is that the kitten will recover due to atrophy of nerves and muscles. This is particularly important in rescue work where a litter is not found until the kittens are several weeks old. By that stage the twisted limbs are probably beyond correction. The rescuer must carefully weigh up the likelihood of recovery. In Sophia's case, treatment was ineffective and euthanasia was the only humane option.
Below are 3 photos kindly provided by Thom Bloks of Ardeleana cattery, The Netherlands. The (as yet unnamed) kitten is 4 weeks old and was photographed at 2 days old. At the time the twisting was very noticeable. At 4 weeks old, there is no evidence of twisting and the kitten walks normally. According to Thom, "The vet presumes that the leg was placed wrong in the uterus and therefore it took some time to straighten out. It may also be that this condition may have come about because of extremely hard labour. The mother had very strong contractions for about an hour whereby I could see the kitten but it was not coming out."
Twisted Hind Limbs in Oriental Kitten (photos copyright 2003, Thom Bloks)
In a breeder situation, the decision to treat may be influenced by the kitten's potential as a show or breeding animal. Its genes may be too valuable to give up without attempting treatment.
In a rescue situation, even where the twisted limbs are noted early enough to attempt treatment, there remains the issue of (wo)manpower, time and funding of any veterinary support to treatment. Where devoting time and energy to a single kitten would be to the detriment of dozens of healthy kittens, the euthanasia of a potentially treatable kitten may be an agonising, but necessary decision.
Tashia White-Sumner (Princeton, Indiana, USA) reports that this very young kitten (placenta still attached) was found tangled in brush behind her house and was apparently born to a grey stray cat in the neighborhood. Unfortunately it was unable to feed and was already being attacked by flies. Though small, it didn't appear to be premature or have anything severely wrong with it apart from being abandoned and having twisted hind legs. Sadly, because it was newborn, abandoned by the mother and in a bad way when found, it was not possible to help it.
Naomi Kolb, a breeder of Devon Rexes, had a twisted limbs kitten (plantigrade posture with medial rotation of the hind limbs) born in a litter in May 2010 (photos below). As well as the twisted limbs, the kitten was tailless. Although she can stretch out her legs and feet behind her, she has problems tucking her feet back under when she crawls and there is a concern that a spontaneous "Manx type" mutation has affected the nerves to the hind limbs resulting in the twisted limb presentation. Hopefully massage and exercise will strengthen the hind legs to more normal posture.
Radial Hypoplasia presents different issues for the rescuer/breeder. Unlike twisted hindlimbs, it cannot be rectified by splinting and physical therapy. It is an inherited trait. The individual kittens should be assessed for quality of life and euthanized if necessary. The parent cats should not be bred from again in order to eliminate the defect from breed lines.
CASE STUDY (RADIAL HYPOPLASIA)
The following report is from Carolina Cats, P. O. Box 210705, Columbia, SC 292221 following the progress of six kittens, four of which had twisted forelimbs. This was written when the kittens were 8 weeks old.
Of the six kittens born, two with deformed legs died right after birth, and the white kitten with deformed legs died on the fourth day, although until that point it appeared to be doing as well as those who survived. One kitten, the last one born, appears normal in every way - four good legs, all the toes, and even his heart checks out OK! He's a pretty blue boy, and we will probably find him a home this week. The two surviving kittens with deformed legs did not need any help so far. Mama hooked her paw around Tiggeroo, the male brown tabby with no front legs worth speaking of, and he also boosted himself up on his sister or brother's back to get at a nipple to nurse. Perhaps if all the kittens had absolutely no front legs or Tiggeroo had been the only survivor the milk wouldn't have come in, but since the normal kitten, Blue, was able to treadle normally and even the female, Misty, could stimulate the milk to a certain extent, milk flow wasn't a problem. The owners of the cats did not want to give them up until the kittens were weaned, if they survived. Athough they were nonchalant about spaying or neutering, they did feed the cats properly and they were never let outside. We decided the kittens needed the mama cat, and they were well-provided for temporarily.
As they grew, the deformed kittens quickly learned to compensate. They were sitting up on their hind legs before they were four weeks old, although they also use their legs to get about. Mysti, the grey and white female, who has one almost-full-length leg with severely twisted bones and one half-length leg, each with two digits, was able to get into and out of a regular-height litterbox by five weeks of age. The kittens were weaned easily at 5 weeks to dry food. Tiggeroo, the boy with tiny stubby front legs, didn't make it to the box at first, but during the past week did get there on occasion.
I have corresponded with various people about adoption, some of them from the time the kittens were born. One of these was Dorene Schultz in New Jersey, and on Thursday Dorene's friend donated her frequent flyer mileage to her, and Dorene flew down and adopted the kittens. We decided that if she felt she could handle two, it would be better to keep them together and to only have to arrange transportation to one location. The two deformed kittens do gravitate to each other as if they know they each are similar, and different to their fully-formed brother. (I myself have a cutaneous asthenia kitty who wears clothes to prevent his skin from tearing, and a liver-shunt kitty, both of whom are very small for their ages, and although they aren't related they often sleep together or cuddle together, as if they relate to each others' problems). Mysti and Tiggeroo moved into the motel room we booked for Dorene for a one-night stay and acted as if they were quite at home. They hammed it up for the newspaper, who came to write a story about them. Tigger was particularly interested in admiring himself in the mirror.
Our vet examined all three kittens carefully, and could not find anything else wrong with them. We are aware that some defects do not begin to manifest themselves until kittens are 8-12 weeks, but hope nothing else shows up in these little ones.. Mama and Dad are FeLV and FIV negative and seem perfectly healthy - they are not related, and are each about a year old, totally indoor cats. They produced a healthy litter of 7 in December. We had daddy cat neutered 2/28/02. The deformed litter was born May 4. This would be 65 days from the day Asher was neutered. Of course, he may still have been viable for up to 49 days after neuter, according to the literature. Did the neuter/anaesthesia cause the defects? We will probably never know. The owner is certain Angel, the mama cat, did not get into anything (she has a child in diapers, another 4 years old and six children altogether, and I am sure is careful not to expose them to toxins, let alone the cats). The home is clean and tidy. Angel is being spayed on Tuesday, by the way!
Dorene is a former nurse with experience with nursing newborn children with disabilities, as well the elderly disabled; she has worked for veterinarians, does trap-neuter-release of ferals and has a CH (cerebellar hypoplasia, spastic) kitty in a wheelchair cart and an older kitty, a former feral, who has a heart condition. She wanted a companion for Scooter who was not too mobile and who would keep him company, since he can't move much at all. He especially likes kittens, so we think this will all work out very well. So far we have not seen any sores or calluses developing on the kittens' abbreviated legs. One of Tiggy's legs is slightly longer than the other, and he can actually move both of them in towards each other, and he tries to use them to cover what he does in the litterbox, even though they are so short. Dorene is prepared to get them specially-designed carts (we thought maybe one wheel up under the chest, velcroed on?), prostheses, booties, splints, or whatever may help them. We will keep all the e-mail addresses just in case Dorene finds that one or other of the kittens needs more individualized attention once she really gets to know them and starts working with them, but she doesn't really see that happening."