What is a canine unicompartmental elbow (CUE) surgery?

Canine unicompartmental elbow or CUE surgery is an advanced and complex surgical approach that involves resurfacing the weight-bearing portion of the medial aspect of the elbow by placing an implant where the cartilage is now absent.

Osteoarthritis from coronoid disease and other forms of elbow dysplasia may result in complete loss of cartilage on the weight-bearing surfaces of the medial joint structures resulting in what veterinarians call Medial Compartment Disease (MCD).

Most dogs affected by elbow dysplasia are born with this condition due to an abnormality within their genetic makeup. Large and giant dog breeds such as the Labrador retriever, German shepherd and Great Dane are at the top of the most commonly affected breeds. In some cases, a dog can be affected by elbow dysplasia due to malnutrition, injury or lifestyle. Dogs that are extremely active or have daily jobs, such as herding or sporting dogs, can develop this condition due to wear and tear of the joints as well.

How can Medial Compartment Disease (MCD) be treated in dogs?

Medial Compartment Disease (MCD) is the “end stage” form of elbow dysplasia where the inside part of the joint collapses and leads to bone on bone grinding. Options such as oral medications, joint injections, and physical therapy may be beneficial in some MCD cases for at least a period of time and should be discussed with your veterinarian. When surgical treatment is deemed necessary, as is often the case, the Canine Unicompartmental Elbow (CUE) is a safe and effective option to consider. It was developed as a treatment for MCD in dogs when arthroscopic treatment and nonsurgical options either won’t work or have been tried and are no longer successful.

Prior to CUE surgery, routine diagnostic exams will need to be completed to ensure your dog is healthy enough to undergo surgery. Additionally, blood samples are usually collected to evaluate your dog’s internal organ functionality, and your veterinarian will most likely need to x-ray the affected limb to use as a reference throughout the CUE operation.

By focusing on the specific area of disease (the medial compartment), the CUE implant provides a less invasive, bone-sparing option for resurfacing the bone-on-bone medial compartment while preserving the dog’s own “good” cartilage in the lateral compartment. This medial resurfacing procedure reduces or eliminates the pain and lameness that was caused by the bone-on-bone grinding.

CUE Humeral Implant

What can I expect after my dog has CUE surgery?

You will be sent home with antibiotics and pain-relieving medications for your dog. A bandage will be placed on the limb, which you will need to keep clean and dry. The bandage will be changed after one week and maintained for at least two weeks after surgery. Sutures will be removed approximately two weeks after the procedure. Your dog must be restricted to rest in a kennel or crate, with controlled leash walking only for the next eight to twelve weeks after surgery. During that time, exercise will be strictly limited until your veterinarian recommends physical therapy to safely accustom your dog to the limb alteration.

A follow-up examination and assessment of healing with your veterinary surgeon will be needed after the 8-12 week period following surgery, at which time, rehabilitation exercises will be initiated to work towards the goal of a progressive return to full activity levels by six months after surgery.

Efficacy of Canine Unicompartmental Elbow (CUE) surgery in dogs

Canine unicompartmental elbow is a highly effective form of treatment for mature dogs suffering from MCD. The implant provides an artificial cushion between the weight bearing surfaces of bone, relieving pain and providing the dog with a greater range of motion.

Elbow Dysplasia in dogs

What is Canine Elbow Dysplasia?

Elbow dysplasia is a general term used to identify the group of disorders that affect many dogs, especially large breeds and working/performance dogs. There are four types of disorders or abnormal development that classify as forms of elbow dysplasia that may occur in a canines elbow which include:

  • Fragmented coronoid process (FCP) – A small or large fragment of the bone breaks off and moves around inside of the elbow joint. This small fragment of loose bone irritates the lining of the joint, wearing away the cartilage of the humerus.
  • Osteochondritis dissecans (OCD) – OCD of the elbow usually occurs in young dogs who show signs of lameness in one or both limbs. Osteochondritis dessicans is a condition where a piece of cartilage comes loose or completely pulls away from the surface of the joint, resulting in pain and inflammation.
  • Growth rate incongruity – The radius bone and ulna bone grow at different rates. Growth Rate Incongruity or Elbow Incongruity is a term used to describe the imperfect conformation of the joint, which causes the cartilage to wear away rapidly.
  • Ununited anconeal process (UAP) – A bone outgrowth within the elbow becomes detached and causes irritation and degeneration. UAP is a condition noted by a bony protuberance within the elbow. This area becomes detached from the ulna, causing joint irritation and degeneration.

All of these types of elbow dysplasia result from abnormal development of the bone and cartilage of the elbow in dogs and lead to osteoarthritis.

What are the symptoms of elbow dysplasia in dogs?

Elbow dysplasia is the most common cause of forelimb lameness in dogs. The abnormalities start to occur when the puppy is going through a rapid growth phase (typically 4-10 months of age), but often the symptoms are not noticed until the dog is much older. Changes in activity level, limping, swollen elbows, pain in the elbows, decreased performance, and behavioral changes are some of the visual signs you may observe if your dog has elbow dysplasia.

How do veterinarians diagnose elbow dysplasia in dogs?

Medial compartment disease (MCD) can be diagnosed in dogs as young as 6 months of age or may become apparent in any age after that. Your veterinarian will perform a careful orthopaedic examination of your dog to diagnose the problem. With elbow dysplasia, the veterinarian may note joint thickening and swelling, pain on joint manipulation, and loss of range of motion. X-rays should be taken to confirm the findings and characterize the type and severity of elbow dysplasia. Advanced imaging, such as arthroscopy of the joint, CT scan, or MRI, may also be necessary to fully determine the extent of the problem and the most appropriate treatment options.

Fragmented Medial Coronoid Process (FMCP) is by far the most common form of elbow dysplasia in dogs. In this disorder, the bone and cartilage on the medial part (inside portion) of the elbow joint develop cracks (microscopic or larger) which can cause the symptoms of elbow dysplasia and lead to osteoarthritis. The cracks may result in the formation of fragments of bone and cartilage that may remain in place or move in the joint like a pebble in your shoe.

Arthroscopy performed by an experienced surgeon is an ideal way to deal with FMCP in dogs as it allows accurate and comprehensive diagnosis, as well as immediate treatment. Through two small incisions, the veterinary surgeon is able to carefully assess the joint, remove the fragments, and treat the surrounding cartilage as needed. Arthroscopic treatment of FMCP has a high success rate of removing the abnormal cartilage and bone, slowing down the progression of osteoarthritis, and improving the symptoms of the disorder. However, it is not a cure and the osteoarthritis will still progress to some degree and needs to be monitored long term with a likely need for further treatments later in the dog’s life.

As the dog ages, the osteoarthritis from FMCP and other forms of elbow dysplasia may result in complete loss of cartilage on the weight-bearing surfaces of the medial joint structures resulting in what veterinarians call Medial Compartment Disease (MCD). This is the “end stage” form of elbow dysplasia where the inside part of the joint collapses with eventual grinding of bone on bone. Interestingly and importantly, the larger lateral (outside) part of the elbow joint appears normal in the vast majority of patients.