This article was written by Pamela Francis for the FLCV in 2010. Pam's work remains an up to date and relevant summary for people who are considering buying a Finnish Lapphund. If you would like to read about steps that breeders can take to reduce the chance of hereditary disease, refer to the club breeding guidelines 2017-2020.
Hip Dysplasia is simply a poor formation of the hip joint. It is a condition that occurs in many species, including humans! The hip joint is a ball and socket joint. There should be a nice, neat and snug fit between the head of the femur (the “ball”) and the acetabulum (the “socket”). If this fit is too loose, the resulting wear and tear through everyday use can result in a range of attendant problems, including the development of arthritis and pain upon movement. This is the condition known as hip dysplasia.
The degree of looseness can vary in individual dogs from very little to a whole lot! Naturally, there is a greater likelihood of problems resulting, when there is a higher amount of looseness. However, just to complicate the issue, there are actually examples of dogs in all breeds, running around quite normally and pain free, with hardly a hip socket at all! Also, as Lappies are a light, medium sized breed, a Finnish Lapphund with any kind of mobility problems caused by poor hips is very rare. The diagrams below explain the different degrees of hip dysplasia. (Source: Orthopedic Foundation for Animals)
Grading: 0-4 (Excellent)
This classification is assigned for superior conformation in comparison to other animals of the same age and breed. There is a deep seated ball (femoral head) which fits tightly into a well-formed socket (acetabulum) with minimal joint space. There is almost complete coverage of the socket over the ball.
Grading: 5-10 Good
Slightly less than superior but a well-formed congruent hip joint is visualized. The ball fits well into the socket and good coverage is present.
Grading: 11-18 Fair
Assigned where minor irregularities in the hip joint exist. The hip joint is wider than a good hip phenotype. This is due to the ball slightly slipping out of the socket causing a minor degree of joint incongruency. There may also be slight inward deviation of the weight-bearing surface of the socket (dorsal acetabular rim) causing the socket to appear slightly shallow.
Grading: 19-25 Borderline
Borderline: there is no clear cut consensus between the radiologists to place the hip into a given category of normal or dysplastic. There is usually more incongruency present than what occurs in the minor amount found in a fair but there are no arthritic changes present that definitively diagnose the hip joint being dysplastic. There also may be a bony projection present on any of the areas of the hip anatomy illustrated above that can not accurately be assessed as being an abnormal arthritic change or as a normal anatomic variant for that individual dog. To increase the accuracy of a correct diagnosis, it is recommended to repeat the radiographs at a later date (usually 6 months). This allows the radiologist to compare the initial film with the most recent film over a given time period and assess for progressive arthritic changes that would be expected if the dog was truly dysplastic. Most dogs with this grade (over 50%) show no change in hip conformation over time and receive a normal hip rating; usually a fair hip phenotype.
Grading: 26-35 Mild
Mild Hip Dysplasia: there is significant subluxation present where the ball is partially out of the socket causing an incongruent increased joint space. The socket is usually shallow only partially covering the ball. There are usually no arthritic changes present with this classification and if the dog is young (24 to 30 months of age), there is an option to resubmit an radiograph when the dog is older so it can be reevaluated a second time. Most dogs will remain dysplastic showing progression of the disease with early arthritic changes. Since HD is a chronic, progressive disease, the older the dog, the more accurate the diagnosis of HD (or lack of HD).
Grading: 36-50 Moderate
Moderate Hip Dysplasia: there is significant subluxation present where the ball is barely seated into a shallow socket causing joint incongruency. There are secondary arthritic bone changes usually along the femoral neck and head (termed remodeling), acetabular rim changes (termed osteophytes or bone spurs) and various degrees of trabecular bone pattern changes called sclerosis. Once arthritis is reported, there is only continued progression of arthritis over time
Severe Hip Dysplasia: assigned where radiographic evidence of marked dysplasia exists. There is significant subluxation present where the ball is partly or completely out of a shallow socket. Like moderate HD, there are also large amounts of secondary arthritic bone changes along the femoral neck and head, acetabular rim changes and large amounts of abnormal bone pattern changes.