An alternative fixation method for femoral varus derotational osteotomy in spastic cerebral palsy: the Rush rod.

The objective of this study is to present the clinical and radiographic data collected from patients who were treated with a varus derotational osteotomy using Rush rod fixation and compare this to published norms of outcomes using blade plate fixation. A retrospective chart and radiograph review was conducted after identifying 44 patients with 61 hips who underwent varus derotational osteotomy with Rush rod fixation at our institution between 2006 and 2016. We identified 44 patients with 61 hips who underwent the procedure. Information from follow-up clinic visits was gathered and any complications were noted. The patients' radiographs were analyzed to measure neck-shaft angle, center-edge angle, and acetabular index. At the time of surgery, 44 patients (61 hips) also had soft tissue releases performed, 44 (61 hips) had an open reduction of the hip, and 39 (55 hips) had Dega acetabular osteotomies performed as well. The average pre-operative neck-shaft angle was measured at 163.0° (range 128-180) with average post-operative neck-shaft angles measuring 111.3° (range 85-167). The acetabular index improved from an average of 33.3° (range 16-60) to 16.4 (range 4-35). Post-operative Center-Edge Angle measured 29.7° (range 5-45). There were no infections or cases of avascular necrosis of the femoral head. We present an alternative fixation method for performing varus derotational osteotomy of the proximal femur in children with cerebral palsy using the Rush rod. In our retrospective analysis of 61 hips undergoing this procedure, we present comparable radiographic outcomes with decreased complication rates. Level of evidence: Retrospective comparative study to previously published results, Level III.

Effect of pressure applied during casting on temperatures beneath casts.

BACKGROUND: Burns and pressure sores are common injuries during cast application. Various factors such as water temperature, padding, and cast material layers may play a role in these injuries; however, the effect of cast molding on temperatures and pressures has not been investigated. This raises the following questions, does the application of molding during cast application: (1) alter skin level temperatures in a variety of cast materials? and (2) risk inducing either thermal injury or pressure necrosis? METHODS: An upper extremity model was created to measure pressure and temperature underneath casting materials. Cast padding, water bath temperature, and cast thickness were standardized. A 3-point mold was simulated using 3 casting materials-Fiberglass only, Plaster Only splint, and Plaster splint overwrapped with Fiberglass-while pressure and temperature were recorded. RESULTS: : Pressure application led to a statistically significant (P<0.0001) increase in temperature at the sites where the mold was applied although absolute temperature did not reach the theoretical burn threshold of 49 to 50°C for the casting materials studied. With pressure applied, the Plaster/Fiberglass combination reached an average peak temperature of 47.9°C, which was maintained for up to 6 minutes. Neither Fiberglass nor Plaster Only reached peak temperatures of this magnitude (average of 42.7 and 43.6°C, respectively). Peak (369 mm Hg) and highest residual (21 mm Hg) pressures were below harmful levels. CONCLUSIONS: Pressure application during casting is a risk factor for burn injuries. Care should be taken when molding a plaster splint overwrapped in fiberglass by waiting until the plaster has fully cooled. CLINICAL RELEVANCE: Combined with other known risk factors, the pressure from molding a cast could increase the likelihood of causing cutaneous burns.