"Dealer's Choice": Univalve Location Effect on Skin Surface Pressures in Long Leg Casts

Fiberglass long leg casting is often used to treat specific lower extremity fracture patterns in children. However, cylindrical casting limits swelling, increasing risk of compartment syndrome. To account for edema, casts are frequently univalved, but it remains unclear whether univalve location affects skin surface pressures (SSPs) in long leg casts. We hypothesized that a lateral univalve would decrease anterior SSP, whereas univalve location would not affect posterior SSP in long leg casts.

A 100-mL saline bag attached to a pressure transducer was placed along the anterior or posterior compartment of a volunteer underneath 20 and 26 long leg casts, respectively. The casts were randomly assigned to receive either lateral or medial univalve. The bag was insufflated with water to 100 mm Hg, and change in SSP was recorded with univalve (stage I), univalve with 3-mm spacer (stage II), univalve with 6-mm spacer (stage III), and bivalve (stage IV). Statistical analysis was done to detect an SSP difference of 10 mm Hg.

In the anterior and posterior compartments, no notable differences were found in SSP change within any stage between lateral and medial univalve. Comparing stage I and stage IV, a notable SSP change was found across all anterior and posterior compartment groups (P < 0.001, 95% confidence).

No notable difference was found in anterior or posterior SSP in long leg casts with either medial or lateral univalve. Our data support a "dealer's choice" that the practitioner may select either medial or lateral univalve to reduce anterior and posterior SSP.