Cat - Care Post Hip Dislocation

What do we mean by hip dislocation?

The hip is a simple 'ball and socket' joint located at the top of both hind limbs. This joint has a wide range of movement in all directions and its efficient function is essential to normal hind limb movement. The joint itself is comprised of the acetabulum which is a cup shaped depression in the pelvis (this forms the 'socket') and the femoral head which is part of the femur (thigh bone), this structure forms the 'ball'.

The stability of the joint comes from the joint capsule, a short ligament that connects the ball to the socket and the muscles that surround the hip.

In the case of hip dislocations, the 'ball' (top of the thigh bone) is displaced from the socket (acetabulum) and in most instances will be positioned above and in front of the acetabulum. The commonest cause of hip dislocation is a road traffic accident. However the hip may be dislocated by any traumatic injury in the area of this joint.

It is interesting to note that an increasing number of cats, especially pedigree cats, are developing hip dysplasia (poor hip joint conformation) similar to a disease seen in dogs. This condition may make it more likely that an individual cat may dislocate its hip.

What clinical signs should I expect?

Your cat may have been missing from home for a few days as it may find it difficult to get home if it has been involved in a road traffic accident. In addition to having a dislocated hip there may also be other injuries (some of which may be more serious). Most cats with a hip dislocation will have a severe hind limb lameness and some may not be weight bearing at all on the affected limb. The affected limb is often carried in a flexed (folded up) position with the knee joint rotated inwards towards the cats body. The affected limb may, in some cases, be rotated so far inwards that it crosses over in front of the non affected limb.

How is this condition diagnosed?

Examination by your veterinary surgeon will reveal discomfort or pain on manipulation of the hip joint. In addition to this there may be a grinding sensation felt by your vet when the hip is moved. A comparison of the lengths of both hind limbs will reveal that the affected limb is apparently shorter. The diagnosis will be confirmed when a radiograph (x-ray) is taken, this will establish that the hip is indeed dislocated and which direction it is dislocated in. A radiograph (x-ray) will also reveal if a fracture has occurred in this area that may make replacement of the hip joint more difficult. It must be borne in mind that your cat may have more serious life threatening injuries that will have to be treated before your vet will even consider dealing with the dislocated hip.

What is the best treatment for a dislocated hip?

In most cases of hip dislocation it is desirable to replace the ball in the socket. The only time when it may be reasonable not to do this is if your cat has some other illness or there are factors which make it a very poor anaesthetic risk. In these cases, where the hip is left dislocated, a 'false joint' will form which has some useful function to the cat. In many cases of hip dislocation it is possible to replace the ball in the socket by manipulation under anaesthesia (closed reduction), this is more likely to be the case if very little time has passed since the hip became dislocated (i.e. less than 3 days). If this is possible your cat may be put in a special bandage to prevent the hip from redislocating, this bandage will remain in place for 4-14 days. Some cats will not tolerate this bandage very well. A close eye must be kept on this bandage to ensure that it is not too tight and is not causing damage to the cat's leg.

In some cases of hip dislocation it will either not be possible to replace the ball in the socket or the ball will keep slipping out of the socket. In these cases an operation is indicated to firmly secure the ball in the socket. Most of these procedures involve the use of stainless steel pins and/or suture material. Some of these procedures will necessitate the removal of some or all of the pins at a later date. The actual choice of which procedure is performed is often related to the preference of your veterinary surgeon.

What post-operative care does my cat need?

If it has been possible to manipulate the ball back into the socket your cat will, in most cases, be prescribed a short course of painkillers to be administered by mouth. In addition to this, your cat will have to be confined indoors. This will usually involve either confining your cat to one room in the house or in some cases confining your cat to a very small enclosed area such as a large cage. Your cat will have to be confined in this way for around 3-4 weeks before it is safe to let your cat venture outdoors again. As stated, your cat may have a bandage on the affected leg which should be carefully inspected daily to make sure that there are no problems with it.

In cases that have had an operation, painkillers and antibiotics will normally be given. It will again be necessary to confine your cat as directed by your veterinary surgeon. This will again be for a period of 3-4 weeks. At this point it may be necessary to have a second operation to remove any pins that have been used in the repair.

What is the long-term outlook for my cat?

If the ball has been successfully replaced and the correct post operative treatment has been adhered to it is unlikely that the hip will re-dislocate. In many cases the hip joint will regain full function and will require no further treatment for the lifetime of the cat. However, some cats may develop a stiff or arthritic hip months or years after the dislocation which may require additional treatment. This situation also applies to those cats where it has not be possible to replace the ball into the socket.