Cheryl May's page on Ununited Anconeal Process

Ununited Anconeal Process

I developed this web page to help others locate information on Ununited Anconeal Process, a form of elbow dysplasia. Your decisions for treatment may be different from mine. I am not a veterinarian and you should consult a veterinarian or orthopedic surgeon for more details and assistance. This page is not intended to offer advice, but merely to relate how my husband and I dealt with our dog Lacy's specific problem. Sometimes I think it is helpful to know that others have experienced similar problems and to learn what they decided, whether it agrees with your own choice or not.

If your puppy has ununited anconeal process, I wish you the very best of luck. It is certainly a disappointing circumstance. Some of the dogs I'm aware of have done very well with the ulnar osteotomy, and two who had the surgery at the same time as Lacy, had the anconeal process unite, although it took much longer than the surgeons expected. Others have not fared so well, and had to have the loose portion removed later. You can help your dog by keeping weight under control - a thin dog with UAP does a lot better than an overweight one.

I receive a lot of mail asking how Lacy is doing now. Her surgery was done just a few days before her six month birthday. She is now four and she has earned a German Shepherd Club of America Temperament Certification, a Herding Instinct Certification, an AKC Companion Dog title, and a Novice Agility Preferred title. She also has a UKC AG I title. We are very much enjoying running agility in NADAC, and in the AKC Preferred classes, with their lower jump heights. She also is in training for advanced obedience and tracking.

For those who are interested, I feed Flint River Ranch, and give her glucosamine/chondroitin supplements, and Vitamin C. Very rarely, she will get a Rimadyl, if she shows pain, but this is uncommon. My vet says we have been very lucky. Although I would like to tell you that surgery will work as well for your dog as it has for Lacy, I simply do not know. While Lacy's anconeal process has never united, she doesn't limp and is doing well. Her surgeon cleared her to do all activities and dog sports. Initially, he did not envision that she would be sound unless the AP united. It did not unite, but she doesn't limp, and is not in pain.

The Orthopedic Foundation for Animals' Web site lists elbow dysplasia as a polygenic inherited disorder. Polygenic is defined as "coming from more than one gene pair. These traits are more complex than the typical dominant or recessive genetic trait. The additive interaction of the genes can cause variable results and the gene can be easily passed on to other generations without being identified."

Lacy was spayed before her first season - I would never breed a dog with elbow dysplasia. I wish that more breeders of German shepherd dogs took elbow dysplasia as seriously as they do hip dysplasia. GSDs are 34th in incidence of hip dysplasia, but sixth in incidence of elbow dysplasia. The OFA ratings of the individual parents are important, but so are those of the brothers and sisters of the sire and dam. Siblings of dogs with elbow dysplasia have a higher chance of producing it, even if their own elbows are normal.


For activities to do with your recuperating dog, click here. And if you have additional ideas for the activities page, please send me e-mail and I may add your suggestions.


In June and July 1999, my German shepherd puppy, Lacy, became lame three times following play over a five week period. Since I was planning to have preliminary radiographs done for OFA anyway, I made an apppointment to have these done to see if she had a problem. She did. Lacy was diagnosed with Ununited Anconeal Process at 24 weeks of age. She didn't fit the profile of the typical UAP patient.

UAP occurs most commonly in large male German shepherds. Twice as many males are affected as females. About a fourth of affected dogs have the problem in both elbows. Lacy is a small female who had the condition in both elbows. The condition has also been reported in other large breeds including the Saint Bernard, Great Dane, Labrador retriever, Irish wolfound and others, and in Basset hounds, French bulldogs and dachsunds.


The problem is thought to be polygenic, that is, caused by a number of elements which could include an inherited developmental anomaly, a metabolic defect, a genetic disturbance of normal growth-stimulating hormone, environment, nutritional deficiencies, etc. Both Lacy's parents have normal elbows certified by OFA.

Some researchers identify the problem as an incongrous growth between the radius and the ulna, causing extra pressure on the anconeal process that prevents it from uniting. This is the theory behind the newest surgical treatment, ulnar osteotomy, in which the surgeon cuts out a small piece of the ulna to relieve pressure on the anconeal process, allowing it to unite. This surgery has been studied and reported in journals by Swedish researchers.

Treatment Options

After identifying the problem, the difficult decision is answering the question, "What to do?"

The latest option, announced in June 2002, is elbow joint replacement. At present, the surgery is only available at Iowa State University, but should be available nationwide in the future.

When Lacy was diagnosed, a friend did a literature search through the veterinary journals to help us make an informed decision about treatment. The options at the time were to do nothing and relieve pain through medication, or to opt for surgery. Because Lacy was young at the time of diagnosis, and because our plans for her were to participate in obedience and agility, we opted for a surgical solution, hoping to salvage her performance career. If we had chosen to do nothing, it is my understanding that she would have developed severe pain over the next two years.

Lacy's surgery was performed July 27, 1999, by Dr. James K. Roush, head of surgery at Kansas State University's Veterinary Medical Teaching Hospital, and his surgical team. They performed an ulnar osteotomy on each of Lacy's front legs.

Surgical treatments These were the options open to us:
* Excision of loose anconeal. This is the traditional surgery. Unfortunately, removal of part of the elbow joint, which occurs in this surgery, makes the elbow less stable. It does, however, relieve pain. If we had chosen this option, it would be less likely that Lacy could participate in agility, but could probably do obedience, even at advanced levels.
* Lag-screw re-attachment. In this surgery, a lag-screw is inserted through the anconeal process, pushing the ununited parts together. The goal is to have the bones grow together. I was unable to locate research articles demonstrating success with this method.
* Ulnar osteotomy. This is the method we selected for Lacy. It involves cutting a 2 to 4 mm horizontal slice of bone from the ulna, and inserting a fat graft between the bones so the bone doesn't grow back together too quickly. This gives the anconeal process an opportunity to unite.

The journal articles I found most helpful were:
* "Ununited Anconeal Process in the Dog" by Lennart Sjostrom, DVM, in Vol. 28, Number 1, January 1998 Veterinary Clinics of North America: Small Animal Practice.
* "Ununited Anconeal Process in the Dog. Pathogenesis and Treatment by Osteotomy of the Ulna" by Lennart Sjostrom, DVM, H. Kasstrom, and M. Kallberg, in the Journal of Vet. Comp. Orthop. Trauma 1995, Volume 8, pages 170-176.

Things to do with your recuperating dog!

Useful links I found on the Web

  • Radiographs of abnormal elbows
  • OFA info on elbow dysplasia
  • Results of Proximal Ulna Osteotomy as a Treatment for Ununited Anconeal Process (UAP)
  • Elbow Disease in Growing Dogs by Roger Lavelle
  • Canine Rehabilitation
  • rec.pets.dogs: Canine Medical Information faq
  • Elbow dysplasia, a report from Dr. R. B. Lavelle and Dr. V. P. Studdert on the Second International Elbow Working Group Meeting held in San Francisco in March 1990.
  • Diseases of the elbow joint by Ron E. Mandsager, DVM.
  • Southern California Surgical Group article on elbow dysplasia.

  • Dr. Henry De Boer Jr. on Elbow Dysplasia: Part 1

  • Dr. Henry De Boer Jr. on Elbow Dysplasia: Part 2

  • Canine Elbow Dysplasia

  • J.D. Wheat Veterinary Orthopedic Research Laboratory UC Davis School of Veterinary Medicine.

  • Small Animal Orthopedics journal, articles and links on Elbow Dysplasia by Dr. Daniel D. Lewis, DVM, Diplomate ACV

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