ABSTRACT: The aim of this article is describe the basic contents of a typical orthopaedic plating kit, with guidance on how to recognise the different types of plating systems. The next article wilt cover the more common plates that are used in veterinary practice and will show how to measure and identify different types of bone screw.

During the process of fracture-fixation planning, the veterinary surgeon will decide on an appropriate fracture repair modality for a given case. This will depend on the bone involved, the type of fracture and the age, species and condition of the patient, along with the experience and individual preferences of the surgeon involved.

The costs associated with the repair need to be within the means of the owner, and aftercare requirements should also be taken into account, both from the point of view of the owner’s ability to comply and the animal’s temperament!

This article provides guidelines on recognition of the equipment commonly used for one of these repair methods – the application of a bone plate.


Practices tend to keep a huge range of orthopaedic equipment ranging from fully fitted dedicated kit boxes containing a range of screws, plates and equipment – down to a few odd unidentified bits and pieces bought in the past and abandoned in a drawer (Figure 1).

Figure 1: Cortical plating kits

So what is in the kit? A typical cortical plating kit contains the following items: 

• range of plates and screws 

•  malleable bending template 

•  appropriate drill bits 

•  soft tissue protector for taps and drills 

•  tap and tap handle 

•  screwdriver 

•  depth gauge 

•  countersink

•  insert sleeve and load/neutral drill guides.


All systems use a screwdriver which can have several different tip shapes. The commonest two are the hexagonal Allen key’ type for cortical screws and the flat blade style used for Sherman self tapping screws. There are also cruciate screwdrivers available for 2.4 titanium screws and 3.5mm Sherman screws.

Star drive screwdrivers are also available and are usually used for locking screws. Figure 2 shows a range of screwdriver tips. Some will also include a sleeve which is used to pick up small screws and hold them in place until they are partially screwed home (Figure 3B).

Figure 2: A selection of orthopaedic screwdriver tipsFigure 3: A range of orthopaedic equipment 

If you are not sure what type of system you have, start off by looking at your screwdriver!

Load/neutral drill guide

Load/neutral double-ended drill guides have a very specific use (Figure 3E). They are made to position a drill accurately in the centre of the screw hole of a dynamic compression plate (DCP), i.e. in neutral position, or to place this off centre to allow compression to be applied. The load end of the guide has an arrow marked on it which is pointed towards the fracture line during use.

Each guide is marked with the size of the drill with which it should be used. As these are made to tight tolerances, trying to use a slightly oversized drill will cause jamming – for example, using a 2.7 drill rather than a 2.5 for 3.5mm cortical screws will jam and destroy the drill guide. An expensive mistake as the drill guide would have to be replaced.


Most kits will also include a tap (Figure 3H) which will have either an integral T-bar handle or will fit to a quick-release handle (Figure 3C).

A tap looks like a long screw with additional grooves running the length of the thread. The tap threads are very sharp and are used to cut a thread in the bone for non-self-tapping screws to follow.

The debris from the cutting operation is pushed into the longitudinal grooves of the tap, away from the freshly cut threads, and removed with the tap.2

Taps should be handled with care both to prevent operator injury and to preserve the cutting edges. They cannot be sharpened efficiently, so should be discarded when blunt or damaged. When being used, taps trap soft tissue very easily, so should be used with a soft tissue protector (Figure 3I) and cleaned immediately after use.

Dried-on tissue wrapped round a tap can be very difficult to remove! Also pay attention to clearing the longitudinal grooves of bone debris. The most efficient and least damaging way of doing this is by using an ultrasonic instrument cleaner.

Depth gauge

Depth gauges are used to measure the hole drilled to assess the length of screw required (Figure 3A).2 Other than in special cases, screws used to secure a plate should engage both cortices of the bone and project slightly beyond the far side. How much depends on the type of screw – the object is to engage full rings of thread in the trans-cortex.

Depth gauges vary depending on the manufacturer. Some measure the actual depth of the hole, whereas others are adjusted to include an allowance for the head of the screw. To check which type you have, draw the measuring probe back into the handle until it is flush with the tip of the gauge and check the reading on the measuring scale.

If the reading is higher than 0, the gauge includes an allowance for the screw head. Most manufacturers can supply a chart indicating what needs to be added to the measurement reading to select the most appropriate screw length.

Insert sleeve

As insert sleeves are small pieces of equipment they can easily be lost. T hese small, mushroom-shaped guides are designed to be used for a lag screw procedure, and are made specifically for each screw size. The internal diameter of the guide accepts the pilot drill for the screw; the outer diameter is the same as the clearance drill, i.e. the same diameter as the screw.

So an insert sleeve for a 3.5mm cortical screw has an inner diameter of 2.5mm and an outer diameter of 3.5mm. In use, the surgeon drills the near cortex of the bone with the larger drill, removes the drill, places the insert sleeve into the hole created, and then drills through the far cortex with the pilot drill. After removing the sleeve – measuring and tapping the far cortex, if required – the screw is inserted and tightened. 

The screw does not grip the first (glide) hole but grips the far cortex, pulling the fragments together and creating compression (the lag screw effect).1-1


Countersinks (Figure 3J) are used to remove the sharp edges of a hole in bone. This is usually to allow a screw head to seat well on the bone when a washer or plate is not being used. If this is not done, microfractures can occur around the lip of bone; eventually resulting in loosening of the screw or splitting of the bone fragment.

It is also useful to countersink the edges of bone tunnels used for suture material – for example, the tunnel in the tibia used with lateral suture cruciate repairs. This reduces the likelihood of damaging the suture material on the sharp bone edge resulting in premature failure.

Bending template

Bending templates are malleable strips of metal, usually aluminium, which are bent to the shape of the bone and then used as a guide to contour the bone plate to match.1 This minimises the need to take the plate in and out of the operating field repeatedly, thus reducing tissue damage and the risk of infection. These are available in different sizes to match common plate profiles.

Drill bits

Drill bits are an essential part of any orthopaedic kit (Figure 3G). Each screw has its specific pilot drill and clearance drill (Table 1).

Some drill bits can be sharpened; others should be regarded as disposable. The supplier of your bits can confirm which type you have; but as a rule of thumb, drill bits which are marked with a code or diameter should be able to be sharpened.

If in any doubt about a drill bit it should be discarded.

Depending on the type of bit, expect to drill between 10 and 20 holes from each drill bit. Blunt drill bits will cause a build-up of heat in bone when drilling a hole. Excessive heat kills bone (thermal necrosis) and results in screws loosening about a week or so after surgery.

Given the potentially serious sequelae of using blunt drills, using a new bit per procedure should be considered, particularly in long-bone plating in large dogs where many holes are needed. At the very least, a simple method ol monitoring frequency of drill bit usage should be devised.

Plate-bending levers

These are used in pairs (Figure 3F) for bending plates to fit the bone. Unfortunately a common disadvantage of these is that the plate tends to shoot out of the surgeons hands when they are being used!


This is by no means an exhaustive list ot plating equipment. There are many other drill guides, such as the triple drill guide (Figure 3D) which is used for the accurate placement of drills and small wires, and alternative plate contouring devices, such as presses and pliers. Take the time to go through your orthopaedic kit and, with the aid of instrument catalogues, work out the extent of your orthopaedic range.

No matter what you have in your kit, a little time spent making sure it is well maintained and that the contents can be easily located will make everyone’s life easier. Clean instruments thoroughly in an appropriate cleaning solution and then lubricate them.

If the equipment is not used regularly, store it clean, dry and lubricated. It will then be ready to autoclave for use.

Part 2 of this article will consider the orthopaedic implants that are in common use in veterinary practice.


Linda Capewell VN

Linda qualified in 1988 after 10 years in practice with the PDSA in Sheffield, as one of the first group of the charity’s VNs. She spent a total of 26 years with the PDSA, and then in 2004 she left and joined Veterinary Instrumentation as veterinary technical support manager. She now deals with a wide range of queries every day.

To cite this article use either

DOI: 10.1111/j.2045-0648.2012.00184.x or Veterinary Nursing Journal Vol 27 pp 226-228


1. JOHNSON. A. L.. HOULTON, J. E. F.. VANNINI, R ; AO Principles o( Fraclure management in the Dog and Cat. AO Publishing. 2005 Switzerland.

2. COUGHLAN. A. and MILLER. A.; Manual of Small Animal Fracture Repair and Management, [ed] BSAVA Cheltenham 1998 

3. DENNY. H. R. and BUTTERWORTH, S. J ; A Guide to Canine and Feline Orthopaedic Surgery 4th edition Hamish Blackwell Scientific. Oxford 2008.


Thanks to Veterinary Instrumentation for implants and instruments shown.

• VOL 27 • June 2012 • Veterinary Nursing Journal