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.

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.

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."

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.

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.

TWISTED FORELIMBS (EXCLUDING RADIAL HYPOPLASIA)

Nicole Rutledge (2013) has a 3 year old domestic shorthair female named Ellie. Ellie was adopted from a local animal shelter and the first thing most people notice are her big eyes rather than her twisted forelegs. Ellie has bilateral twisted forelimbs. She walks a little oddly; scooting her front limbs instead of picking them up. However, she's a very happy and healthy cat with only minor mobility issues. The only medical problem it has caused is with her claws. Ellie cannot use them like normal cats and can’t naturally file them down by scratching. Nail trimming was not an option, due to the fact she doesn't Nicole to handle her paws. This resulted in her claws overgrowing into her pads. The only option was declawing, which Nicole does not otherwise support, except where it is medically necessary and a last resort. Without the problem of claws overgrowing, Ellie is more comfortable shuffling around. Because Ellie has adapted and is in no way crippled, there is no need for invasive surgery to straighten the legs. Nicole says it’s sad that many people choose euthanasia for cats like Ellie “deformities are beautiful, and I wouldn't have her any other way.”

Radial Hypoplasia is far more severe than Ellie's case and 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 in severe cases may have to be euthanized. It is possible to adapt a household to accommodate a cat with short, twisted forelegs (see Living With a Disabled Cat) and many do lead happy, albeit restricted, lives. The parent cats should not be bred from again in order to prevent further kittens with radial hypoplasia.

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.