This Issue's Rounds Question -
Please tell us: What is a carpal boss, or carpe bossu?

(responses to be published in next issue)

In the last issue of Body Cast, Rounds asked: What technique/materials do you employ while performing a cast wedge?

The following responses were received:

From Suzanne Groulx:
Ex. long leg cast # tibia (P.O.P. or fibreglass)
X-ray in long leg cast. If bone is not well-aligned, we can improve alignment without cast change. Pinpoint where cast needs to be wedged. Cut a line with cast saw and use cast spreaders to insert cast wedge. (Cast wedges come in different sizes.) Tape cast wedge in place. Repeat x-ray. If x-ray is acceptable, wrap cast with P.O.P. or fibreglass.

From Derek Gauthier:
A cast wedge is a simple technique used to alter/improve the anatomical alignment of a bone in a cast. An open wedge is most commonly used. It is very important to understand your x-ray interpretation. Anterior - Posterior? Varus - Valgus? Apposition? The alignment and angulation of the bone will help determine where to place the cast wedge. The cast can be used to your advantage as a fulcrum to achieve your goal.
Once you have determined where to place your wedge, you need to cut the cast approximately three-quarters around with the wedge being the centre of the cut. Different materials can be used to maintain an open wedge. The "cast wedge adjuster" is a perfect little tool. But for those cheap clinics, a piece of wood or cork may do the trick. Just make sure it is well­protected from migration. Then, just simply spread the cast to desired width and place the wedge in the opening. Once an x­ray confirms you've done a fine job, apply casting material around wedge making sure to extend at least six inches above and below. You're done. Now, wasn't that easy?

From Jim Pike:
The cast is already on a leg and an x-ray has been done. The decision has been made to change the alignment of the fracture site. Circumferential cutting of cast at the fracture site is done to three sides making sure the upper and lower cast stays intact with each other, like a hinge. Then, use your cast spreader to determine your desired width. Cast wedges come in different sizes ranging from 10 mm up to 30 mm. After you have spread the cast, you might need to place some Webril in the space. The radiolucent cast wedge will hold the cast apart at the desired angle. This procedure is followed up with another x­ray. Then you reinforce with P.O.P. or fibreglass.
Materials used: plaster of Paris or fibreglass, cast cutter, cast spreader, Webril, desired size of radiolucent cast wedge, marker for making lines around cast, and x-ray machine.

From Edward Clancey:
Materials: goniometer (used for measuring angles). marker. cast cutter, plastic or cork to fill space in open wedge, pre- and post-wedge x-rays
Technique: Once the patient and x-ray have been reviewed by the orthopaedic surgeon, the angle of correction at the fracture site is determined with the use of a goniometer. The angle to be corrected may be marked out at level of fracture onto the cast. There are two types of wedging - open and closed. We prefer the open wedge as it decreases the chance of skin being pinched, as is a complication of closed wedging. To correct a midshaft fracture of the tibia that has a five-degree varus angle, a circumferential cut is started on the medial side of the cast at level of fracture and stops before the line of cut joins on the lateral side. The portion of plaster left acts as a hinge and prevents rotation at fracture site. The cast is then manipulated to open it on medial side, thus correcting the deformity. Plastic or cork wedges are placed in the opening to hold it and plaster is applied over this area to reinforce. Circulation and sensory are checked. Another x-ray is done to confirm alignment of bone.

From Vital Robichaud:
Ideally, the procedure is performed three weeks after injury when the fracture is mobile but sticky and correction is almost painless.
Method: can be done using only a ruler and marker pen. On x­ray film, draw lines along the long axes of the proximal and distal fragments of the tibia. Measure the diameter of the cast at the level of the fracture and mark this distance on the ideal line extended down from the end of the proximal fragment, starting at the intersection of the two lines. Draw another line to meet the axis of the distal fragment creating an isosceles triangle with equal sides. Measure the distance that is the thickness of the required wedge of this plan.
Repeat the same procedure on the lateral x-ray film. Draw a line around the cast at the level of the fracture. Mark the position of the wedge and cut the line with the plaster saw leaving a quarter of the cast intact to act as a hinge opposite the midway point between the position of the wedge. Cut pieces of cork the size required for the wedge and apply sufficient force to the cast to open the gap and correct the angulation. Insert the cork into the wedge to hold the reduction. X-ray post-procedure to ensure satisfactory correction. Reinforce the cast around the wedge site if correction is satisfactory. Then follow up.

Responses were also received from: Livain Arseneau, James Carragher, Eric Christiansen, Adrian Crossman, Norm Ellsworth, Melvin Gillingham, Richard Grenier, Leo Helfer, Mary Anne Lash, Brian Lavallee, Cam Longphee, Lynn Lough, Lori MacDonald, Gary Marshall, Blair Matheson, Joe Maulucci, Javad Movasseli, James Punwassie, Cheryl Rivers, Bert Sheppard, Angela Wentzell, Heather Wong, Neuville Yao and Tom Yorke.