Dogs sometimes injure a structure in the knee known as the cruciate ligament. The purpose of the cruciate ligament is to hold the joint steady when the dog walks, runs, or jumps. Trauma to the ligament results in pain and limping, and often requires major corrective surgery. Later in life, arthritis almost always develops in the knee that was injured.
Dogs commonly injure their cruciate ligaments by landing wrong while playing fetch, or falling down stairs, or by being tackled by another dog. Large-breed dogs are at increased risk. So are overweight dogs.
And a study published in the December 1, 2007 issue of the Journal of the American Veterinary Medical Association (JAVMA) suggests that the timing of surgical neutering may be a risk factor as well.
The paper is titled “Risk factors for excessive tibial plateau angle in large-breed dogs with cranial cruciate ligament disease.” Here is a quote from its abstract.
Conclusions and Clinical Relevance — Results suggested that early neutering was a significant risk factor for development of excessive [tibial plateau angle] in large-breed dogs with [cruciate ligament disease]. (J Am Vet Med Assoc 2007; 231:1688 – 1691)
Translated into English, the authors suggest that early neutering may be a risk factor for knee injuries in large dogs. Early neutering (at less than six months of age) appears to affect the growth patterns and orientation of bones in the knee. This may increase the risk of knee injury later in life.
Does this mean that large dogs should not be neutered at less than six months of age? It’s too soon to tell. The appropriate timing of neutering is a complex issue. This study adds another piece to the puzzle.