Disease or trauma may cause damage to the hip joint which results in bony spurs, thickening of the joint capsule, pain and decreased range of motion. For example, hip dysplasia is a condition that causes laxity (looseness) in the hip joint. The loose fit of the hip joint stretches the joint capsule and causes the femoral head to move excessively in the acetabulum. This excessive motion causes micro fractures of the acetabulum. The body responds with new bone growth, but unfortunately this new growth is irregular and causes arthritis and painful inflammation.
Hip arthritis is painful, and depending on the degree of disease, can severely affect the quality of your pet’s life. Treatment for hip arthritis ranges from management of the disease with diet, exercise restriction, and pain medication, to surgical correction with total hip replacement surgery. When considering which option is right for your dog, factors such as your pet’s comfort, ability to enjoy life, your expectation of return to function, and financial aspects should be considered. The advantages of a total hip replacement are the elimination of pain (instead of management) and a near 100% return of full function. In most cases no medication is required following recovery from the surgery.
An alternative surgical treatment is FHO (Femoral Head Ostectomy) in which the femoral head is removed but not replaced. This procedure may reduce pain but the loss of a true ball and socket joint limits the return of function and usually results in a change in gait or limp.
Patients that could benefit from a total hip replacement are dogs that have moderate to severe hip pain requiring chronic medication and who or are reluctant or unable to exercise to their full potential.
Because hip pain frequently affects both hips equally, many dogs with hip arthritis do not have an obvious limp. Symptoms such as reluctance to climb stairs, tiring during routine exercise, or stiffness rising from rest are typical. Total hip replacement also allows full return of function to dogs suffering from traumatic hip luxation (dislocation) and hip fractures. Due to the sizes of implants available, most dogs that undergo a total hip replacement surgery must be at least 35 lbs (15 kg).
Hip replacement surgery can be performed in patients as young as 10 months old, and has been performed on many senior patients as well. Once a patient is referred to Boundary Bay Veterinary Specialty Hospital the surgeon thoroughly examines your pet and their medical history. Radiographs (x-ray) are taken to measure for implant size and to determine which hip dysfunction is the most severe. Only the most affected hip joint is operated on at one time. If both sides are to be surgically corrected, then the first side will be allowed to heal for at least 8 weeks before proceeding to the second side. The surgery requires that your pet stay in hospital for 1 to 2 days before going home. Your pet will receive 24-hour care while hospitalized to ensure that he is comfortable during his post-operative recovery.
During total hip replacement surgery, the surgeon removes the “ball” section of the femur and replaces it with a titanium implant. The ball (head) of the implant is attached to a stem that is inserted into the femur and is held in place using locking screws. The patient’s acetabulum (socket) is then prepared for the cup implant by removing the arthritic bone. The new cup is positioned and impacted into place. The ball of the implant is placed into the cup, which now acts as the socket, and the placement is tested to ensure full range of motion and proper positioning. The surgery is completed and post-operative radiographs are taken to assess the final placement. The permanent stability of the implants results from bone growth into the implant pores and titanium surfaces (osseous integration). Initial ingrowth takes 4 to 6 weeks and matures over 4 to 6 months.
At Boundary Bay Veterinary Specialty Hospital, Dr. Geoffrey Hutchinson uses a KYON Zurich Cementless Total Hip Replacement system. This titanium and titanium alloy implant system was developed in Switzerland in 2001 and to date has been used in over 9000 dogs. This new system offers several advantages over other types of total hip replacements including immediate stability of the femoral implant, extremely low rate of implant wear, low risk of implant complications, and reduced risk of infection. The fourth generation of this system includes a synthetic diamond coated ball, femoral component strengthening upgrades, and several modifications of the cup to ensure rapid bone integration and an extremely low coefficient of wear. The absence of bone cement eliminates associated complications including aseptic loosening and premature wear due to migrating cement particles. The new hip is designed to last for your pet’s lifetime.
During the initial recovery period, your dog will have an incision with staples. It is extremely important to prevent your dog from licking the incision as this may cause an infection. For the next 10-14 days you will need to keep the incision clean and dry. For 6 weeks after surgery, exercise restriction is mandatory; this means no running, no jumping, no climbing stairs (off-leash), and leash walks only outside to go to the bathroom. In the house, your dog will need to be restricted to a small confined area with secure footing.
Follow-up visits are scheduled for 2 weeks after surgery, 6 weeks, 4 months, and then annually to assess function and monitor implant-bone integration. Clients are encouraged to call or recheck at any time if there is a concern.
Generally your dog will start wanting to walk with her new hip a few days after surgery. Postoperative pain medications are dispensed and very good return of comfort is expected within 1 to 2 weeks. Over the first 6 weeks while her bone grows in to stabilize the implant she will need to be strictly controlled and kept on-leash. After the recheck at 6 weeks a gradual return to normal activity is allowed over another 8 weeks.
As with any surgery, complications can occur with a total hip replacement. Complications that are known to occur with this surgery include luxation (dislocation of the implant), infection and fracture. These complications are most likely to be seen in the first 4 weeks after surgery. At Boundary Bay Veterinary Specialty Hospital we work diligently to minimize these concerns and in the unlikely event that a complication should arise we will work through it with you.