CCL Tears And Early Spay And Neuter: Is There a Connection?

Is there a connection between early spay and neuter?

The data has been compiled. I went through our patients over the last ten years who are over the age of three years old. A summary of the data shows that while 2.1% of our spayed and neutered patients had to undergo ACL surgery, only 0.3% of the intact animals had to have the surgery.

This represents a seven-fold increase for animals that have been spayed and neutered before the age of 6 months to have to undergo knee surgery for anterior cruciate rupture.

CCL Tears And Early Spay And Neuter: Is There a Connection?

Staggering results

These results are staggering (so much so that I am submitting these results for publication…if we are published I will post the article and everyone can see the specifics of the study…dodon’t want to get too technical here).  In pouring through the archived studies there does seem to be a possible explanation.

The study

A study of 1444 Golden Retrievers performed in 1998 and 1999 found that animals spayed and neutered at less then a year of age were significantly taller than those spayed or neutered at more than a year. 

The sex hormones, by communicating with a number of other growth-related hormones, promote the closure of growth plates at puberty, so bones of neutered or spayed animals continue to grow longer.  These dogs have longer limbs, lighter bone structure, narrow chests, and narrow skulls.

This delay of growth plate closure can result in different angles from one set of long bones to another.  

Tibial plateau angle

For example, a study by Dr. Kathy Linn and her resident Dr. Felix Duerr showed that spayed and female animals have a significantly greater tibial plateau angle. This is because the tibial growth plate stays open longer then it is supposed to and the tibia continues to grow longer relative to the femur in “fixed” animals as opposed to those animals who are intact.  It is widely known and accepted that animals with a greater tibial plateau angle are at a much higher risk for anterior cruciate injury.  Perhaps Dr. Michael will delve into this on later posts.

It is these changes in bone structure than that subject prepubertally spayed and neutered animals to anterior cruciate rupture.  

Other related orthopedic conditions

Other orthopedic abnormalities like osteoarthritis and hip dysplasia have also been correlated with early spay and neuter.  In addition, spayed and neutered animals tend to gain weight, are more likely to develop obesity, and have decreased lean muscle mass.  Obesity itself is a major risk factor for orthopedic abnormalities and injury.

The increased risk of anterior cruciate rupture and surgery is just one more reason to think strongly about whether we should be spaying and neutering our pets….particularly before puberty and before normal growth has finished.

Related articles:
Talk to me about CCL Injuries

Further reading:
Spay Neuter And Joint Disease

Categories: CCL injuriesEarly spay/neuterJoint issuesKnee issues

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Dr. Robert Foley

Dr. Foley attended Cornell University’s School of Agriculture and Life Sciences, where he first met his friend, Dr. Michael Ferber. Dr. Foley graduated in 1992 and stayed in Ithaca after graduation to continue working in Dr. Alan Nixon’s laboratory at the NYS College of Veterinary Medicine. Together they studied the efficacy of chondrocyte implantion to treat osteoarthritis and osteochondritis dissecans (OCD) lesions in horses. In 1994, Dr. Foley was accepted into the NYS College of Veterinary Medicine at Cornell University. Dr.’s Ferber and Foley were reunited in vet school and became roommates. Dr. Foley graduated in 1998 and moved to Brooklyn, NY where he practiced for two years. Subsequently, Dr. Ferber invited Dr. Foley to come work with him at his family-owned practice, The North Shore Animal Hospital, in Bayside, Queens, and the two were reunited one last time. After two more years Dr. Foley became a partner within the group. The group decided to open up a new practice together on Long Island. Dr. Foley took a leading role in directing and growing this practice which became South Bellmore Veterinary Group. Over time the practice outgrew its original footprint and today operates as a beautiful, multi-doctor, 5000 square foot, state-of-the art, fully functioning animal hospital. Dr. Foley continues his role as Director of Medicine and Surgery of the practice today. His particular interests include dermatology, soft tissue and ophthalmic surgery. Dr. Foley is passionate about educating his clients on issues such as over-vaccination and the dangers of early spay and neuter.

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