Welcome to our second case of the month! If you were with us last month, you'll remember that we discussed a broken leg in a cat. This month we have another cat with a broken leg, with some extra considerations. If you want to see last month's case, scroll down to the bottom of the page.

MIS-STEP TAKES A TUMBLE

This case involves another fracture that we treated near the end of 1999. The severity of this fracture was worse than last month's, and we had the added complication of advanced age.

HISTORY

Mis-step was a 17-year-old cat who in her younger days liked to climb ladders. She'd climb up, look around, then climb back down. She'd done this plenty of times in the past, but this time was different. Mis-step's parents were doing some remodeling on the outside of their house. This involved some scaffolding and ladders, and no one expected that Mis-step, as old as she was, would be too adventurous. Wrong! When one of her parents was on the scaffolding, Mis-step decided to follow. Unfortunately, she wasn't as graceful as she used to be, and no one noticed her climbing. She slipped and fell backwards off of the ladder. Immediately it was apparent that she'd hurt a back leg pretty badly.

PHYSICAL FINDINGS

On examination, Mis-step was painful near the middle of her lower leg (tibia). She had obvious swelling just a short time after the injury, and her leg turned at an abnormal angle. We took some x-rays.

X-RAY RESULTS

Mis-step's x-rays showed a fracture of her tibia. Unlike Uh-oh's break last month, which appeared along a line of natural weakness, Mis-step's break occurred near the middle of her leg. There were multiple pieces which attested to the amount of force with which she'd landed.

Remember that 2 views help us get a 3-dimensional impression of an x-ray? The shape of the fracture pieces suggest that, in addition to the impact from Mis-step's fall, there had also been some twisting of the leg as she landed.

TREATMENT

Before we addressed fixing Mis-step's fracture, we had to handle concerns involving her age. A 17-year-old cat is a pretty old cat! (See "How old is your pet?" for more...) One estimation would make her about 78 years old. For a pet her age we have several concerns regarding surgery, including:

We did a few things to ensure her safety before and during her surgery. First, we did some blood tests to evaluate her organ function (we'll discuss this in more detail next month). The testing (along with our physical exam) revealed that she should be able to handle anesthesia. The next thing we did was to change the type of anesthetic that we used. In most cases, we use a combination of injectable and gas anesthesia; however, in high-risk cases we often use gas only, with excellent results. With Mis-step we used gas anesthesia only. During anesthesia we also monitor a patient's heart and respiration closely (an EKG helps us identify any abnormalities quickly). Finally, to support her circulatory system, we gave her physiologically balanced fluids during the procedure (because she showed no sign of problems and the fluids were used as a precaution only, they were administered under her skin - subcutaneously - rather than intravenously).

Because of the multiple fragments present in her fracture, several pieces of hardware were required to stabilize the bones: a pin and several wires:

and a close-up:
Mis-step actually required 2 repairs of her injury. The night after her first surgery, one of the broken bone pieces shifted and part of the repair came loose. A second, shorter procedure allowed reinforcement of the affected area.

OUTCOME

Mis-step was checked regularly during her healing. As with Uh-oh, she had to be confined; also, like Uh-oh, it was later judged that her pin would be left in place, primarily due to her age, to avoid unnecessary surgery later. There are reasons we like to remove pins after fracture repairs, which we'll discuss in a later case. Here's Mis-step after a couple of months:

If you look closely, some of the original break is still visible, but healing has also begun (the wispy, lighter areas - see arrows).

She's in the later stages of healing now, and, apart from some cabin fever after the first several weeks of being cooped up, she's been doing well!

DISCUSSION

Mis-step shows that even an older pet can go through a major procedure safely, with proper precautions and a little bit of extra care. She also shows how fracture healing occurs. In the pictures below you can see what callus, or new bone, looks like. In the same amount of time we would expect more complete healing in a younger animal. Much of the reason for exercise restriction after a fracture repair is to protect this delicate structure as it forms and strengthens.

First, here's a close-up of the fracture right after the repair:

Now, here's the same view about 8 weeks later:
Where's the callus?

The cases we've seen so far have been fixed with what we call internal fixation. Broken bones can also be fixed with splints and/or casts, special types of harnesses, and externally placed pins. In a later case we'll look at the different types of fracture repair and why they work (or don't work) in different situations.

Next month we'll take a break from fractures and look at Mis-step's blood tests.

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