Total Hip Replacement

Sending a client for a consultation regarding hip replacement is a large commitment by the client and patient. Even with a diagnosis of hip dysplasia, some patients are very good candidates for hip replacement and others are not. A client must consider many things including cost, aftercare, expected function, and potential complications. This document is intended to answer many of these questions, and also serve as a check list for the primary care clinician who is referring the case. Iowa State University School of Veterinary Medicine and the Lloyd Veterinary Medical Center are proud to offer total hip replacement (Total Hip Arthroplasty – THA) to our referring veterinarians for the benefit of their patients and clients. We have been offering this service for over 25 years and with the recent addition of new orthopedic surgeons and with the support of industry leaders, are expanding our service into being a regional center for hip and other joint replacements. Our surgeons have extensive experience in orthopedics including hip replacements. We offer both cemented and uncemented Biomedtrix THA systems.

The typical candidate is a middle age to older dog with increasing soreness and lameness referable to their hip joints. Typically these patients are slow to rise after sleeping, will tire or become more lame with increased exercise, and can exhibit pain when climbing stairs. The other category are young dogs that are no longer a candidate for a triple pelvic osteotomy, exhibit significant pain and lameness, and are large enough so that FHO may not return them to acceptable function.

The neurologic examination should be within normal limits with no loss of placing deficits, or proprioceptive deficits to the caudal limbs. There will be decreased range of motion, especially in internal rotation and extension of the hip joints. Normal extension should be about 170 degrees and internal rotation is 45 degrees Flexion and external rotation can be normal or decreased. Abduction is often decreased.

Most surgeons will try a trial period of conservative treatment before recommending THA. Some, if not many, patients will respond very well and may resume a more comfortable life without surgical intervention. Conservative treatment consists of weight management, exercise moderation, high quality chondroprotectives, and the use of NSAID medications, either continuously or intermittently for a few days during periods of increased lameness. Exercise should be in the form of low-impact activities such as leash walking and swimming.

Many conditions may look like hip dysplasia. What can be confusing is that many dogs have radiographic signs of hip dysplasia, but their lameness or dysfunction is primarily cause by another condition. This happens frequently. Here is a list of other conditions and how to exclude them.

• Degenerative Myelopathy – This spinal cord degenerative condition occurs frequently in German Shepherds (as does hip dysplasia). The signs you should look for are ataxia, placing deficits, wear on the tops of the toe nails, exaggerated patellar reflexes. I often ask the clients to choose the word “Sore” or “Drunk” in the back end to describe their pet’s problem. Other spinal cord conditions including compressive tumors may also present with these signs. Patients with DM are not candidates for THA.
• Rupture of the Cranial Cruciate Ligaments – CCL conditions are common, often bilateral, and can have a slow onset of clinical signs, just like OA from hip dysplasia. Radiographs may demonstrate hip OA while most of the lameness is due to knee problems. This is VERY common. The patient should be checked for signs of stifle instability including the bump on the inside of the knee some call a “Medial Buttress”. The patient should be checked for drawer and cranial tibial thrust. Radiographs of the stifle can also be taken.If a dog has both severe hip dysplasia and a CCL rupture, the CCL rupture is addressed before the THA.
• Caudae Equina Syndrome – Instability of the lumbosacral joint may result in compression of nerve roots at that area. Since compression of nerve roots can cause pain and dysfunction to the caudal limbs, this can mimic hip dysplasia. The tail may be held very low and the patient may resist being petted around the LS area. Lifting of the tail, palpating over the lumbosacral area, and extending the lower back while not extending the hip joints may elicit pain. Radiographs are often difficult to interpret since many older dogs have radiographic changes including ossifying spondylosis at the LS junction. If we suspect a LS condition, we may request an MRI prior to performing a THA.

Eighty percent of the patients with arthritis in both hips only require one side be operated upon to return them to a satisfactory and comfortable life. The decision on which hip to replace is based on the owner’s observations, the physical examination findings and the hip x-rays. Only one hip is operated at first, usually the clinically most effected side. The decision to operate the second side is made after recovery from the first.

This section is intended to familiarize you with the potential complications of total hip replacement surgery, the implications on immediate care and long-term prognosis, and associated financials if such complications were to arise. This list is NOT exhaustive but provides general information. Information specific to your patient (both medically and financially) will be provided if the situation arises. As with any procedure, there are risks involved and complications that may arise despite our best efforts to mitigate risk. Therefore, we require that every client be well informed of the more commonly reported risks prior to electing THR surgery.

Hip luxation

Total hip replacement is composed of three components, the ball, the socket and the stem that is inserted into the femur (thigh bone) that the ball is inserted onto. The ball and socket are held together by your pet’s muscles and movements. At the time of surgery, we fit your pet for the appropriately sized implants. Stretching of muscles as your pet recovers, excessive activity, or variation in implant angle in combination with your pet’s anatomy may cause luxation or separation (ball pop out of socket) of these implants in the post-operative period. This is most likely to happen within the first 8 weeks following surgery. You may notice this if your pet suddenly is not using the leg as well (he/she may still walk on it), the knee turns outward differently than prior, you notice a bump/lump over the hip, or your pet seems painful. *Please note, it is not uncommon for your pet’s knee to consistently be more turned out for 3-6 months following surgery.*

Luxation post-operatively will require additional surgery (see revision surgery pricing below). Your pet will undergo X-rays and sedated examination to determine the most-likely cause of luxation. Often, this involves replacing a part of the implant to effectively “tighten” the hip but could involve more advanced procedures to change the angulation of implant parts or add additional implants to hold the hip in place as it heals. The specifics for your pet would be discussed prior to the procedure and a more precise cost estimate and prognosis provided.

Femur fracture

There is a low risk of femur fracture during the THR procedure. If this occurs, it will be addressed during the surgery either by placement of wires or a bone plate and screws. This rarely changes the risks associated with post-operative success but may increase the price of surgery by about $1000. Femur fracture after the procedure is rare if your pet is appropriately exercise restricted. However, if experienced, will require additional surgery (see revision surgery pricing below) and may decrease the chance of positive outcome or result in the need for removal of the total hip implants. Signs of fracture would include acute pain, non-weight bearing, severe lameness, or excessive bruising/swelling not associated with the initial incision.

Infection

An important concern with any orthopedic implant placement is infection. We take every precaution to prevent infection through our practices in the operating room, and through screening your pet for any potential sources of bacteria. If your pet has a urinary tract infection, signs of systemic/blood infection, or any signs of skin infection at the site of the surgery, surgery will be postponed until the situation has been resolved. Bacteria that reach metal implants develop a biofilm, or protective barrier, that makes them immune to antibiotic therapy and requires implant removal and/or replacement. Because of this, we generally remove the implants associated with a deep infection and treat with appropriate antibiotics (see complication surgery pricing below), effectively leaving your pet with a femoral head and neck ostectomy (FHO) procedure. Though most pets function acceptably with this procedure, the implications for your pet will be discussed individually.

Pelvic fracture

Very rarely, placement of implants may cause a pelvis fracture at the time of surgery. If this occurs, there is a potential your pet may not be able to receive a total hip implant or may be at very high risk of post-operative failure. If this were to occur, a surgeon would alert you immediately and discuss implications and whether to proceed with surgery.

Sciatic neuropathy

During surgery, significant retraction and work occurs near the sciatic nerve, a critical nerve to the back leg. It is extremely rare for the nerve to be permanently damaged, but initial nerve deficits may be seen secondary to stretching during the procedure. This would manifest as a change in the way your pet walks on the limb, with a very characteristic “flicking” of the lower leg to advance it forward. If this occurs post-operatively, it may take up to 8-12 weeks to regain full function but is unlikely to be permanent. You will need to watch your pet’s toes for any scuffing or scrapes but otherwise no extra care is required.

Patella luxation

Changing the angles and mechanics of the hip may have consequences further down the limb, most common of which is luxation or dislocation of the patella (kneecap). Though uncommon, this may require surgical correction at additional cost (est. $3500-4500) to re-align the kneecap, which will not be performed at the same time as the THR surgery. Your pet will be assessed for this condition prior to surgery, post-operatively, and at recheck evaluations. If this condition is identified prior to THR surgery, correction of the patella luxation will be recommended prior to pursuing hip replacement.

Pulmonary thromboembolism

Very rarely, pets have been noted to have pulmonary thromboembolism (PTE) in the post-operative period and is thought to be clots of fat or blood traveling from the surgical site to the lungs. Though this is less common with our current implants, it is unpredictable and may be fatal or require intensive care such as being on a ventilator.

Even though ISU will take radiographs, these will be very precise radiographs, taken under anesthesia, with several specialized views for surgical planning. Prior to referral, it is best to confirm a diagnosis of hip dysplasia before having a client make a trip. In addition, these images are often helpful during the initial visit as they may suggest the candidacy of the patient, prognosis, and potential for operating the contralateral side.

Hip dysplasia is demonstrated radiographically as laxity of the coxofemoral joints at an early age, and secondary osteoarthritic changes in the adult. This instability results in osteophyte formation, thickened femoral neck, and a shallow acetabulum. The severity of the arthritic changes is not a primary differentiating factor for candidacy for THA. Some patients with mild radiographic changes are candidates due to pain and dysfunction.

1.  Initial consult: At the initial visit we will examine your pet, place an intravenous (IV) catheter, administer sedation, and acquire at least four radiographs (x-rays) of the hips. We also submit blood and urine samples for routine pre-anesthetic evaluation. Once we have reviewed the x-rays to determine if your pet is a good candidate for the THR procedure, we will discuss scheduling for surgery and provide you with instructions regarding pre-surgical care to best prepare your pet to have the procedure performed. Cost: $1000-1200
2. THR Surgery: We will admit your pet the day prior to surgery to allow them to acclimate to the hospital environment and to complete final evaluation of things, such as the condition of the skin over and around the surgical site, in preparation for surgery. On the day of surgery, THR procedures are typically performed first in the day. You will be updated when your pet is placed under general anesthesia and again when the procedure is completed and we have reviewed post-operative x-rays to ensure proper placement of the implants. Please know that, in addition to actual surgery time, there will be time needed to shave and prepare the skin, for movement to radiology and for post-operative images to be acquired. Therefore, after you receive the update call at the beginning of anesthesia, no news is good news. Your pet will be kept in hospital for 1-2 nights after the surgery, until they are comfortable and walking. Cost: $7,000-9,000
3. 2-week follow up: At 2 weeks after surgery, we will assess your pet’s incision for healing (before the E collar can be removed) to ensure the skin is healed and there are no signs of infection. We will also test the hip to ensure it is moving correctly. If there are any concerns, X-rays may be recommended. There is no cost for the recheck visit, but there may be fees for medication refills or x-rays if indicated. Cost: No cost for the examination, additional diagnostics as referenced will carry a cost.
4. 2-month follow up: As long as your pet continues to do well at home, we will plan to see him/her back 2 months after surgery to recheck X-rays and ensure the implants and bone are stable and healing appropriately. Based on these findings, you may be instructed to increase your pet’s activity level. Cost: $700-900

Successful return to good to excellent function occurs in 95% of our cases. Complications can and do occur, and with a total hip replacement can be severe. These include infection, luxation of the hip joint, damage to the sciatic nerve, and fractures of the femur. Most complications can be successfully resolved.

Appointments can be made by calling the Small Animal Reception desk at:

Phone: 515-294-4900
Fax: 515- 294-7520

The most important part of your pet’s recovery is the nursing care that you provide at home. Unlike humans, we cannot control pets’ recoveries with wheelchairs and walking aids, so your pet is relying on you to keep him/her under control. Your pet will feel strong and comfortable on the hip BEFORE the hip has healed in the body, making your job critical during this time period.

1. Setting up the house
   • The most important consideration in setting up your pet’s recovery area is creating a kennel or small space where he/she will be confined when not leashed and directly supervised. If your pet is not used to a kennel or anxious in a kennel, gating off a small room or area of the room is ideal. The area should:
     • Not exceed 3 times the length of your pet from front to back, and 2 times that length wide. For example, a standard Labrador retriever should not be allowed a space larger than approximately 6 feet by 4 feet.
     • Have non-slip floors with no obstructions on which your pet could trip or get a foot caught. Examples would include low-pile carpets/rugs or rubber matting such as yoga mats or interlocking rubber tiles. Loose bedding or bunching carpet should be avoided.
     • A low-profile orthopedic bed. Fluffy pet beds present a chance for your pet to trip or catch a foot, and tall beds are too unstable for walking immediately post-operatively. A 2-3” flat foam orthopedic bed is recommended. No blankets or comforters should be used for the same reason.
     • Baby gates and free-standing toddler barriers are acceptable only if they are tall enough that your pet cannot jump over them.
     • As you are waiting for your pet’s surgical date, consider getting him/her accustomed to this new area so it will be familiar and less stressful. This can be done by having them spend shorter periods of time within this space for enjoyable activities such as working on a Kong. We want this area to be a happy/safe environment with as little stress as possible.
   • The rest of the house may need to be adjusted to accommodate your pet’s recovery as well. Key considerations include:
     • NO free access to stairs. During the first 2 months of recovery, your pet should have absolutely NO free access to stairs. Stairs are only allowed with your pet on a leash and utilizing sling support.
     • No slick surfaces. Any area where your pet will be walking, particularly from the recovery area to outside, should have good footing to prevent slipping or falling. Consider floor runners, yoga mats, or interlocking rubber tiles to make a “runway” to outside.
2. NO RUNNING! As your pet recovers, we are waiting for bone to grow into the metal implants that have been placed. Until this happens (2-3 months), the hip is at its highest risk of failure. Until instructed, your pet must ABSOLUTELY NOT be allowed to run. Short, controlled leash walks are acceptable after the first 2 weeks, and you will receive detailed instructions on how much this can be increased each week. Before the 8-week recheck, you should never exceed 10-minute walks 3-4 times daily. After 8 weeks, you may be instructed to increase leash walking and allow your pet to walk within the house but running should still be avoided at all times until full activity is allowed at approximately 3 months post-operatively.
3. To control your pet’s activity, he/she MUST be on a short leash at all times unless confined to a kennel or small room. This is mandatory for a minimum of 8 weeks following surgery. No running is allowed for at least 3 months following surgery.
4. SLING SUPPORT. You will be sent home with a sling to hold under your pet’s belly. Initially, you can use this to support some of your pet’s weight, if necessary, while still allowing him/her to walk and use the leg. By 2 weeks, you no longer need to be supporting any weight with the sling, but we highly recommend you continue using the sling for the first 2 months of recovery as any sudden slip or fall could lead to serious complications. In this case, the sling is loosely applied under the belly so that it can provide support only as needed.
5. Limit/prevent any exciting stimuli. For some pets this is the doorbell, for others it’s the TV. Anything that makes your pet jump up or run should be removed from the environment during your pet’s recovery. This may involve covering or turning off the doorbell and having people text/call, ensuring your pet does not have a view of the door/mailbox, or keeping the blinds closed in your pet’s recovery area to prevent seeing the yard or street.
6. MEDICATIONS. Most pets require pain medications for 10-14 days following surgery. These medications will be tailored to your pet’s size and specific health needs. Details will be provided in your post-operative discharge instructions. Sedative and/or anti-anxiety medications are generally recommended for the first 2 months of recovery to assist you with the necessary exercise restrictions. These may be continued for the entirety of your pet’s recovery if necessary. As each pet’s response to these medications may vary, please do not hesitate to reach out to us if you feel that the prescribed dosage is overly sedating or insufficient for keeping your pet calm.