The importance of saw blade oscillation angle in knee arthroplasty

In all bone cutting processes, there are two factors that affect the cutting area on a product basis. 1) Saw blade oscillation angle 2) Saw blade dimensions

Saw blade oscillation angle is the angular movement of the surgical power tool cutting head to the right and left. In other words, it determines the maximum distance reached by the cutting edge of the saw blade. (Figure 1)

Figure 1. Saw blade oscillation angle

The oscillation angles of the surgical power tool used in orthopedic surgeries vary between 4° and 5°. There is a direct proportionality between the oscillation angle and the width of the cutting area. In other words, as the angle increases, the incision area will expand.

Especially in knee arthroplasty operations, the movement of the blade is very important. If the blade working inside the cutting guide oscillates too much, it will hit the edges of the cutting guide and make the blade unusable. The blade that oscillates too much can also damage the soft tissue and ligaments around the bone.

The saw blade dimensions are the same, only the effect of the increase in the oscillation angle (4° and 5°) on the incision area is shown in Figure 2.

Figure 2 – Effect of saw blade oscillation angle on incision area

Other factors affecting the cutting area are the blade width of the saw blade and the length of the saw blade. As these two measures increase, the incision area will increase.

In Figure 3, the oscillation angle and saw blade length are the same. The result of only the cut width change in the incision area is clearly seen.

Figure 3 - Effect of cut width on incision area

In the example where the blade width and oscillation angle remain constant, only the saw blade length changes (Figure 4), the incision area will still increase.

Figure 4 - The effect of the cut depth on the incision area


In surgeries using cutting guide, such as knee arthroplasty surgeries, the surgical blade length is usually calculated as 90 mm. Because this is the minimum length required for the blade passing through the guide to reach the bone. In some surgical power tool brands, this length can be 85 or 95 mm, as the saw blade connection point sizes differ.

In cases where the area where the saw blade will be used is narrow and in cuts made in sensitive areas, choosing narrow and short blades will reduce the cutting angle and will allow a more controlled incision.

When purchasing a surgical power tool, attention should be paid to the motor oscillation angle. If this angle is more than 5°, the blade will oscillate too much and will require the use of a short blade. In cases where a minimum blade length is required, such as knee arthroplasty, there may be difficulties.

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