What is elbow dysplasia? Elbow dysplasia refers to the abnormal development of the elbow joint, wherein the three bones of the joint (humerus, radius, and ulna) do not fit together perfectly. This leads to areas of abnormally high contact pressure, resulting in various problems within the joint, such as fragmented medial coronoid process (FCP), osteochondritis dissecans (OCD), ununited anconeal process (UAP), and medial compartment disease. Essentially, “elbow dysplasia” serves as an umbrella term encompassing several conditions affecting this joint.
- What are the Signs of Elbow Dysplasia?
- How is the Diagnosis Confirmed?
- Fragmented Medial Coronoid Process
- Osteochondrosis Dissecans
- Ununited Anconeal Process
- Medial Compartment Disease
- Is Surgery Recommended?
Regardless of which of the above four conditions is present, the signs of elbow dysplasia are the same. Typically, affected dogs display lameness in one or both front legs, stiffness (especially after lying down), and reluctance to exercise. Often, the front limbs’ feet appear turned out, making coming downstairs awkward due to sore elbows.
The signs are most commonly observed between 6 and 10 months of age, although some dogs may only present symptoms as middle-aged or older adults, when advanced arthritis is already present.
Orthopaedic examinations usually reveal elbow swelling and pain, with a restricted range of movement as the joint thickens due to arthritis. However, in a small number of cases, dogs experience painful but non-swollen elbows, making the diagnosis challenging.
Diagnostic imaging is needed to confirm the diagnosis and x-rays are usually the first test that is performed. Ununited anconeal process (UAP) is usually readily confirmed on x-rays, but the other conditions (FCP, OCD and MCD) cannot always be distinguished. The most reliable non-surgical test for these is a CT scan. Arthroscopy or “keyhole surgery” is also a very reliable method for identifying elbow dysplasia and it also enables minimally invasive surgery to be performed when indicated.
The term osteochondrosis refers to an abnormal development of the cartilage on the end of a bone in the joint. It is an inflammatory condition that occurs when the diseased cartilage separates from the underlying bone. It most commonly affects the shoulder joint but the elbow, hip, knee (stifle), or hock (tarsus) may also be affected.
Which breeds of dogs are likely to be affected by this condition?
This is a developmental disease that typically occurs in rapidly growing large breed dogs between 6 and 9 months of age and tends to occur more often in male dogs. The cause of OCD is unknown.However, this disease is more common in dogs receiving too much energy, protein and calcium in the diet. Other factors may also include genetics, rapid growth, trauma, lack of blood flow, and hormonal factors.
What are the signs of OCD?
Dogs that are affected by OCD are typically limp or are lame in the affected leg or legs. They may hold or position the leg differently than normal to reduce weight bearing. During an orthopaedic examination, when pressure is applied to the affected joint or when the joint is manipulated, the dog may cry out in pain. The affected joint may be swollen and warm to the touch. In some cases, the lameness may be mild and intermittent, while in other cases, the dog may be in constant pain and avoid bearing weight on the affected leg.
How is OCD diagnosed?
The results of a lameness examination may be suggestive of this condition, especially if the shoulder is the affected joint. If one of the other joints is affected, such as the stifle (knee), hip, hock, or elbow, other bone conditions must also be considered, including hip dysplasia, patellar luxation, and elbow dysplasia.Because of the possibility of permanent lameness, your veterinarian will recommend diagnostic testing, especially if the lameness persists for more than 2 weeks. Radiographs (X-rays) are usually performed to investigate lameness. Several radiographs of each affected leg are necessary to get an accurate assessment of various bones and joints. In many cases, this will require a short-acting anaesthetic or sedative to achieve the optimal positioning for diagnostic purposes. In dogs under 6-7 months of age, X-rays can be challenging to interpret due to the presence of growth physes or growth plates. To reach the diagnosis, it may be necessary to have the X-rays examined by a veterinary radiologist.In some cases, an ultrasound of the joint or an arthroscopic examination (inserting a small camera into the joint) may be required to reach or confirm the diagnosis.
How is OCD treated?
The OCD lesion can vary in severity, ranging from a crack in the cartilage, to a cartilage flap, to a completely detached fragment of cartilage that is floating around in the joint, called a joint mouse.If a dog is young (less than 6 months old) and if the defect is a crack or a very small flap of cartilage, it may heal if the dog has strict rest and activity restrictions for several weeks. Medications to relieve inflammation and supplements to promote joint health will usually be prescribed. If the lameness does not improve following this conservative approach, if the cartilage flap becomes folded in the joint, if the cartilage defect is large, or if a piece of cartilage breaks free, surgery will be required to remove the defective flap or the floating piece of cartilage. This may be done by surgically opening the joint or by using an arthroscope. In certain cases, the surgeon will transplant normal cartilage and bone from another joint or from a non-weight bearing area of the affected joint to improve healing (osteochondral allograft transfer). In other cases, a synthetic implant may be placed to help reconstruct a smooth joint surface (synthetic osteochondral resurfacing). Whatever the surgical technique, the remainder of the cartilage surface will be inspected and any areas of defective cartilage will be debrided or removed.
What is the prognosis following surgery?
The prognosis varies depending on the joint that is affected. If the shoulder joint is affected, the prognosis is good; if the elbow joint is affected, the prognosis is guarded. In all cases, the prognosis improves if surgery is performed early in the course of the disease. Weight control is important to avoid unnecessary stress and inflammation in the joint.
The anconeal process of the ulna is part of the elbow joint. This part of the bone develops from a separate centre of growth to the rest of the ulna, but the two parts join together at around 4 months of age. Abnormal development of the elbow (dysplasia) can lead to pressure on the anconeal process which stops it from joining on to the rest of the ulna. This loose, bony fragment causes pain and lameness and contributes to articular damage within the elbow joint.
How is UAP diagnosed?
Ununited anconeal process is most commonly diagnosed using simple radiography. However, in some subtle cases where the anconeal process remains loosely attached, it is necessary to use computed topography (CT) to diagnose the condition.
How is UAP treated?
If the diagnosis is made in young dogs (generally under 8 months of age), then the ununited anconeal process can be fixed back on with a screw. In these cases, the ulna needs to be sectioned (“ulnar osteotomy”) to take the abnormal pressure off the anconeal process and to allow it to heal. Arthroscopic examination of the joint is recommended as many dogs with ununited anconeal process also have other changes such as FCP. In older dogs the ununited anconeal process rarely joins back on to the ulna even with surgery and may need to be removed. In dogs with mild lameness, it is usually best to leave it in place
In some dogs the abnormal pressure of one joint surface on the other leads to the cartilage being worn away. The underlying bone is then exposed, and the joints become very inflamed and arthritic.
This form of elbow dysplasia carries the poorest prognosis as it is not possible to reverse the cartilage loss. Several surgical procedures have been developed to try and move the forces of weight bearing away from these areas (proximal dynamic ulnar osteotomy and sliding humeral osteotomy). These have not been scientifically proven to be of clinical benefit and are a last resort
In short, no. The underlying problem in elbow dysplasia is abnormal development of the joint, and it is not possible to reverse the process and make the joint normal. All dogs with elbow dysplasia will develop arthritis to some degree even if they undergo surgery. This must be taken into consideration when deciding on whether to operate or not. Many dogs can be managed effectively using non-surgical or “conservative” measures:
- Very careful control of body weight.
- Controlled exercise, avoiding boisterous activities such as running, turning at speed, chasing a ball, rough and tumble with other dogs, braking sharply and jumping down to land on the front legs.
- Hydrotherapy is beneficial as it works the muscles without overload the elbow joint. This is a good way to keep dogs fit and to help with weight control.
- Dietary supplements such as omega-3-fatty acids, glucosamine and chondroitin sulphate may relieve some of the joint discomfort and stiffness. Prescription diets are available for arthritic dogs, and these can be beneficial.
- Prescription medication such as anti-inflammatory drugs may be required on either a daily or as-needed basis.
Determining the best treatment for a dog with elbow dysplasia is difficult and many factors need to be taken into consideration.