Elbow Dysplasia
About the Elbow
The elbow is a hinge joint composed by humerus, radius and ulna.
Image courtesy of Hill`s
What is Elbow Dysplasia?
Elbow dysplasia is a syndrome that includes a variety of pathological lesions, which leads to arthritis, pain, and reduced range of motion of the elbow joint. The pathology develops because anatomic anomalies lead to abnormal contact between the bones within the joint. The abnormal relation between the three bones (joint incongruity) causes an overload of some specific areas of the joint during the normal movement of the limb, which results in cartilage damage, microfracture and arthritis.
The most common primary lesions are:
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Microfracture of the ulna - Fragmented or ununited medial coronoid process (FCP)
Images courtesy of Hill`s
The red arrows show compression on the medial compartment of the Ulna due to joint incongruency. Recurrent compressions and traumas lead to microfracture and cartilage damage of the medial coronoid process of the Ulna (FCP). The Fracture is marked with a black dots line within the blue circle. The radiographic image on the right revealed a compression on the medial coronoid process (orange arrows), and a clear bent elbow (green line). This leads to an overload of the medial coronoid process of the Ulna and development of significant arthritis.
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Microfracture of the tip of the Ulna - Ununited anconeal process (UAP)
Image courtesy of Hill`s
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Cartilage damage - Osteochondritis dissecans (OCD or OD).
Affected breeds
Young, large- to giant-breed dogs: German Shepherd Dog, Golden Retriever, Labrador Retriever, Newfoundland, Rottweiler, Saint Bernard Dog, Bernese Mountain Dog, and Mastiff, Great Dane and Weimaraner. However, small breed dogs can also be affected by elbow dysplasia: French Bulldogs and Dachshunds, for example.
Diagnosis
Early intervention is recommended to minimise the formation of arthritis. The first diagnosis is based on radiographs (x-rays), however, if this is inconclusive in patients that are visibly painful, then either CT scan or arthroscopic exploration (the use of a camera inside the joint) is necessary to make a definitive diagnosis.
Age of Treatment
Early signs of the elbow dysplasia are detected on radiographic examination between 4 and 6 months of age, also in dogs free from lameness. Radiographs in young patients can reveal the early signs of elbow dysplasia such as those mentioned above (joint incongruity, bone sclerosis, microfracture of the ulna (FCP) and un-union of the anconeal process (UAP)).
Early treatment (especially in those patients that are not yet sore in their elbow joints) with corrective osteotomy can restore joint congruency and patients have a very mild progression of osteoarthritis, meaning a better long-term outcome.
In addition, surgical treatments in younger patients are often less invasive and carry a lower complication rate.
The radiographs reveals sub trochlear sclerosis on the right elbow
The patient was not treated for elbow dysplasia and a radiographs examination was repeated due to the deterioration of lameness. The radiography revealed osteophyte formation within the elbow joint and progression of elbow dysplasia.
Treatment Types
Treatment could be medical or surgical, based on each clinical case.
Surgical Treatment
The surgical treatment chosen for your pet depends on the type of problem diagnosed within the elbow and is best performed as early as possible. Below are three examples of commonly performed procedures.
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Arthroscopy
Arthroscopy (the use of a small camera to inspect the inside of the joint) is used to look for and treat cartilage damage. Furthermore, small bony fragments can be removed with Arthroscopy (UAP or FCP). However, big bony fragments may need to be removed with a more invasive joint surgery called arthrotomy.
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PAUL-2 (Proximal Abduction Ulna Osteotomy)
Images courtesy of Kyonn
Preoperative planning on XR for PAUL-2 surgery
This is a procedure that is used in severe cases of elbow dysplasia and involves a cut on the ulna bone (osteotomy). The osteotomy is fixed with a special plate (plate with a step), which shifts the body weight from the medial (or inner) compartment of the ulna to the lateral one.
Some unpublished data from Clinica Vezzoni reveals that significant pain and lameness improvement can be seen in most patients treated with the PAUL procedure. However, some patients still have a mild degree of lameness depending on the degree of osteoarthritis already present.
79 dogs (Grade 3 and 4 lameness) were treated with PAUL surgery at Clinica Vezzoni. Six months after the surgery, 51% of the dogs were free of lameness (Grade 0), 39% were showing very mild lameness (Grade 1) and 9% were lame Grade 2.
Courtesy of Clinica Vezzoni unpublished data (Vezzoni, 2018)
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Total Elbow Replacement
This surgical technique is only recommended in end-stage elbow dysplasia when the elbow is affected by severe osteoarthritis. This is a salvage, last-resort procedure and involves the replacement of the entire elbow joint with a metal prosthesis.
One notable complication of elbow replacements is post-operative infection. in this case, the implant often needs to be removed, and the joint is treated with an elbow arthrodesis (fusion of the joint in a single bone) or limb amputation.
The invasiveness and risk of complications in this end-stage procedure are one of the many reasons it is highly recommended to intervene early in elbow dysplasia.
Medical (Conservative) Treatment
Medical (or conservative) treatment involves pain management (anti-inflammatories and other pain killers), physiotherapy, bodyweight control and joint supplements.
Many patients can be well-managed with medical treatment alone, however, surgery usually leads to better outcomes and is recommended to prevent rapid progression of arthritis and pain.
It is important to note that all patients with elbow dysplasia, even those that have surgical treatment as well, will require long term management of secondary arthritis. However, early surgical intervention helps to minimize the progression of these changes and reduce the amount of pain experienced by dogs in the long-term.
Reference
Vezzoni (2018) DUO-PAUL Course Zurich/ ED Approach from puppies to adults. Available from: https://www.kyon.ch/community/course-preparation/paul-prep. [Accessed 15/06/19]
