Dislocated hip in dogs: symptoms and treatment

Overview

The hip is a ball-and-socket joint, with the femoral head forming the ball. The matching socket lies in the pelvis. The joint capsule, femoral head ligament and surrounding muscles support the joint.

In a complete dislocation, the femoral head is entirely outside the socket. A partial dislocation is called subluxation. Subluxation is often associated with joint degeneration or hip dysplasia. Partial dislocation of both hips is more common than complete dislocation on both sides.

An untreated dislocated joint may form a false joint. Permanent lameness and chronic pain may result.

Backward and downward dislocation has been estimated to account for 1.5–3.2% of hip dislocations.

Hip dysplasia involves inherited joint looseness.

Causes

Supporting structures fail to hold the femoral head in place

Being hit by a car is a common cause of major injury. A fall or slip can also cause dislocation. The joint capsule may tear. The ligament attaching the femoral head to the socket is usually damaged too. In a severe injury, the gluteal muscles may also be damaged.

The most common direction is forwards and upwards, or craniodorsal. This has been described as accounting for about 80% of canine cases. Another estimate is 90%. In the rare caudoventral dislocation, the head moves backwards and downwards. This can happen when the leg is forced widely out to the side.

Bleeding associated with dislocation can leave a clot in the hip socket. The clot and remnants of torn tissues can make it harder to seat the femoral head again.

Dislocation usually requires damage to at least 2 major supporting structures. The upper rim of the socket is also an important joint support.

Risk factors

Hip dysplasia, a developmental hip disorder, can predispose a dog to dislocation. Less force than usual may then be needed to cause it. Joint degeneration also increases risk.

A study of caudoventral dislocation included 160 dogs. Median age was 8.4 years, with a range of 0.5–19.7 years. Poodles made up 38.1%. Poodle crosses made up 11.3%. A direct link between this dislocation direction and hip dysplasia has not been established.

The caudoventral study recorded 170 separate dislocation episodes. Low-energy accidents accounted for 82.9% of these. Road traffic accidents accounted for 6.5%.

In 10 dogs in the series, the opposite hip also dislocated at a different time.

Typical symptoms

The accident is not always witnessed. With a recent dislocation, a dog usually holds the painful leg up. Leg position changes according to the direction of dislocation.

• The hindleg is severely lame and cannot bear weight normally.

• Your dog holds the leg up or draws it closer to the body.

• The leg looks turned outwards and shorter than usual.

• With dislocation in the other direction, the leg may lie out to the side and look longer.

• Touching or moving the hip causes pain.

• The hip area may be swollen.

• With both hips injured, your dog may be unable to walk.

Lameness from a long-standing dislocation may be less severe than after a recent injury. Mobility alone therefore cannot confirm that the hip is in place.

Complications and consequences

Joint damage, repeat dislocation and other injuries

Dislocation can damage joint cartilage and surrounding soft tissues. The same accident may injure the urinary tract. The lungs or heart may also be damaged.

After closed reduction, the hip dislocates again in about 50% of cases. After open surgical repair, about 10–20% have needed further surgical correction. Implants and support bandages can also cause problems. A displaced support can cause severe limb injury.

The outlook for a functional limb is often good to excellent. The severity of the original injury and previous joint degeneration affect the outcome.

Diagnosis at the vet

The whole dog and other effects of the accident are assessed first

The vet performs general and orthopaedic examinations. Other urgent problems in a severely injured dog are treated before the hip. Blood tests assess organ function and suitability for anaesthesia.

The positions of bony landmarks around the hip and pelvis may change. Moving the hip may produce a grating sensation. Examination is gentle to avoid further cartilage damage.

X-rays are needed before putting the joint back

X-rays confirm dislocation and show its direction. At least 2 views at right angles to one another are needed. They also look for fractures of the femoral head, neck or hip socket. An avulsion fracture where the femoral head ligament attaches may also prevent closed reduction.

Imaging may require deep sedation or general anaesthesia. Additional images of the chest, spine or other limbs may be taken for other injuries. After reduction, another X-ray confirms hip position. Following surgery, images also check implant positions.

Treatment

Closed reduction suits a recent dislocation in an otherwise intact joint

The vet chooses a method according to direction, duration and other damage. Closed reduction means putting the joint back without open surgery. It works best for a normally formed hip without fractures.

The procedure is performed under general anaesthesia to reduce pain and muscle tension. The dog's overall condition is stabilised before anaesthesia. The best chance of success is within the first 24–48 hours. After just 4–5 days, reduction becomes harder and often fails.

In favourable cases, closed reduction may be attempted within the first 3 days. Success also requires the joint to stay in place afterwards. Severe hip dysplasia or Legg-Perthes disease may prevent use of this method.

Support bandages depend on dislocation direction

A hip displaced forwards and upwards may be supported with an Ehmer sling. For a downward dislocation, hobbles may limit excessive separation of the hindlegs. Bandage support may be needed for 10–14 days. It is unsuitable for some limb injuries and limb shapes.

An Ehmer sling is not recommended for caudoventral, or backward and downward, dislocation. It can rotate this hip in a direction that encourages further dislocation.

In the caudoventral study, reduction with hobbles succeeded in 48.8% of individual treatment attempts. Without a bandage, the proportion was 9.1%. With an Ehmer sling, it was 15.2%. Accounting for repeated attempts, hobbles eventually achieved success in 61.8% of cases.

Success meant restored weight-bearing without detectable repeat dislocation. Hobble complications occurred in 31.9% of treatment attempts. The corresponding proportion for Ehmer slings was 60.6%.

Surgery stabilises or replaces the damaged joint

Open repair is considered if closed reduction fails or the joint remains unstable. The joint capsule can be repaired or replaced with a supporting structure. A supporting suture passed through bone tunnels can replace the function of the femoral head ligament.

Severely damaged cartilage or an irreparable joint fracture may require a procedure that replaces normal joint function. Removing the femoral head and neck allows a false joint to form in place of these bones. Physiotherapy helps restore function after this procedure. Hip replacement instead replaces the ball and socket with artificial components.

Hip replacement requires other infections to be ruled out. Joint fluid may be tested for infection when needed. An artificial hip can dislocate. Its components may also loosen. A femoral fracture can complicate hip replacement. Infection is another possible complication.

In the same caudoventral study, supporting suture surgery succeeded in 30 of 34 attempts, or 88.2%. Repeat dislocation can occur more than 6 months after surgery.

Home care protects the repair and restores muscle strength

Pain management and restricted exercise are part of recovery. Healing of the hip's supporting tissues usually needs at least 6–8 weeks of restricted activity. Restrictions last longer after some procedures. Controlled exercises often begin within about 2 weeks of surgery.

After initial healing, gradually increased exercise strengthens muscles. Injuries elsewhere may change rehabilitation progress. Rehabilitation after femoral head removal may proceed at a different pace from that after joint stabilisation.

Jumping and climbing are avoided early on. Outings are controlled on a lead. A single slip or fall can damage the repair. Excessive activity can displace or break implants.

The support bandage's position and any skin rubbing are monitored closely. A mild functional deficit may remain after femoral head removal.

Prevention

Safe car travel is also important in preventing accidents. Use a good-quality dog safety harness on the rear seat. An alternative is a correctly sized travel crate secured to the car's structure. Do not secure a dog in a car by its collar alone.

Not every product sold as safety equipment protects a dog in a collision. Check whether crash testing assessed protection of the dog or simply keeping it in place. Some breeding programmes use hip X-rays to help control inherited joint looseness.

Safety harness buckles should be strong and made of metal.

Important for dog owners

Record when the accident happened and what occurred, even if you did not see everything. Explain whether your dog could bear weight immediately afterwards and whether it had been lame before. Bring previous hip images and details of surgery. Do not pull, twist or try to put the hip back yourself. Ask the practice how to move your dog safely.

Under some official hip assessment schemes, the examining vet must be told about surgery that affects the assessment. In such schemes, an accident-damaged hip that cannot be assessed is marked as having no assessment. The official result then relies on the other hip. X-rays from the time of the accident and the medical history are needed for assessment. A hip operated on for dysplasia is instead recorded as operated.

At discharge, agree how to monitor the bandage and leg use, when follow-up X-rays will be taken and how to assess pain relief. Keep a recovery diary of walking, appetite and rest. Report new severe lameness, a slipping bandage or obvious skin irritation immediately. Give medicines as prescribed.

Frequently asked questions

Can rest treat a dislocated hip?

A hip left dislocated can cause permanent lameness and chronic pain. Treatment puts the joint back and supports its stability. Both closed treatment and surgery also require restricted exercise to protect healing. Putting the joint back may require open surgical repair.

How quickly should the hip be put back?

Closed reduction works best within the first 24–48 hours. After about 4–5 days, it is already difficult and often fails. However, a severely injured dog's general condition is stabilised before anaesthesia. X-rays are always taken before closed reduction.

Why does a hip dislocate again?

Dislocation damages the joint's supporting structures. Repeat dislocation occurs in about 50% of cases after closed reduction. Further injury, joint structure and successful aftercare affect whether the hip stays stable during healing. Repeat dislocation may require surgical repair.

Does my dog always need an Ehmer sling?

No: external support is unsuitable for some injuries and limb shapes. An Ehmer sling is not recommended for backward and downward dislocation. The need for and type of support depend on the injury. When support is used, skin rubbing and bandage position are monitored.

How long is exercise restricted?

The hip's supporting tissues are often protected during healing for at least 6–8 weeks. Restrictions last longer after some repairs. Muscle strength is then restored gradually. Recovery is tailored to other injuries and the procedure performed. Rehabilitation may progress faster after femoral head removal.