Dogs go weak at their knees
Bangers and Mash – awesome names – can’t go anywhere without each other.
They are the classic fox terrier cross jack russell duo – a hundred miles an hour after anything that moves and investigating any little crevice or possible hiding place of a potential foe.
Doris calls them the terrierists. And it doesn’t matter what size the adversary is, they only know one speed, and even rotties and mastiffs are told in no uncertain terms who is in charge.
But lately Mash has been a bit hindered by one of his hind legs, which keeps giving him grief.
When Doris brought the duo in this week, she described Mash as running along quite happily and then all of a sudden he will lift his back leg up and walk on three legs for five minutes. Then he will come right again. In the past week, the lameness had become a lot worse and Mash actually yelped one day when it happened.
With Bangers circling on the floor looking anxious for Mash, who was up on the table, I began to examine Mash from nose to tail. At 3 years of age, there wasn’t anything amiss, but when I got to his left hind leg he became quite tense.
With any lameness, it is important to examine the whole leg, as sometimes what appears to be a knee problem can simply be a case of painful dermatitis in the underside of the paw or a swollen and sore toe. But for Mash, the problem did appear to be his knee.
Small-breed dogs and, in particular, those with curvy or bandy legs have a higher incidence of one particular problem – dislocating knee caps.
I remember one kid at school that was forever flipping his knee cap in and out, which was concerning for all of us other kids. Much like my mother and her false teeth.
So, what is the knee cap and what does it do?
The knee cap is an elliptical piece of bone with a smooth under side. The large muscle group at the front of your thigh narrows down to form one wide tendon, which goes over the front of the knee and attaches on the bony front bit of your upper shin.
For this tendon to sit and slide freely over the front of your knee, the knee cap is incorporated in this tendon. Then the knee cap itself sits in a deep longitudinal groove in the end of your thigh bone. Normally, the knee cap slides up and down inside this groove as you walk or flex and extend your knee.
It’s quite a neat little system. Without the smooth knee cap in the groove, the tendon would flop around and slip to the side all the time.
So, what goes wrong? In bandylegged critters, the muscle narrows to the tendon and then goes over the knee and attaches on the front of the shin, but the attachment on the front of the shin is sitting to the inside because the leg is so curved.
The natural tendency of the muscle and tendon through to the attachment is to be straight when it is under tension, for instance, when you flex your knee. Try it now.
So, for it to be straight in a bowed leg, it tries to pull to the inside, thereby trying to pull the knee cap out of its groove and to the inside of the leg.
Bingo. Sometimes the knee cap will give way and pop to the inside of the leg out of its groove – a dislocated knee cap. This will be locked there as long as the leg is flexed, which tightens the tendon, but may pop back in once the leg extends and the tendon is more relaxed, therefore giving you a small-breed dog intermittent lameness.
Mash’s knee cap was sloppy and easily slipped out of its groove.
Surgery is the best course of action only if it is a consistent problem, and so the next day we had Mash sound asleep, shaved and ready for some carpentry.
Basically, we make the groove deeper, tighten all the side ligaments to hold it in place and sometimes we shift the attachment of that big tendon across a bit so that the tendon is a bit straighter and not so inclined to pull the knee cap to the inside.
After a play with the carpentry gear, Mash was waking up with lots of nice-feeling painkillers on board and was keen to go home as soon as possible. Actually, I think his first thought was about food or where Bangers was.
That afternoon, Mash happily walked out of the hospital with an equally happy Doris and Bangers. We expect Mash to have full and normal use of his leg and be back performing as normal with his tagteam buddy within five to six weeks.
Some cats and larger-breed dogs can also have the same problem, usually as a result of an injury, but luckily it is easily corrected so that they can live a normal happy active life. We can’t do knee replacements, which seem to be a more common human surgery than ever before, but we can fix other things to make our friend’s knees work better.
Have a smiley week, from everyone at Anderson’s.