Calculation of rotational deformity in pediatric supracondylar humerus fractures.

OBJECTIVE: Supracondylar humerus fractures (SCHF) are common in the pediatric population. Cubitus varus deformity (CVD) is the most common long-term complication of SCHFs and may lead to elbow instability and deficits in throwing or extension. Distal fragment malrotation in the axial plane disposes to fragment tilt and CVD; however, no simple method of assessing fracture malrotation exists. This study tested a mathematical method of measuring axial plane malrotation in SCHFs based on plain radiographs. DESIGN: A pediatric SCHF model was made, and x-rays were taken at known intervals of rotation. Five independent, blinded observers measured these films. Calculated rotation for each data set was compared to the known rotation. The identical protocol was performed for an aluminum phantom. RESULTS: The reliability and agreement of the rotation values were good for both models. CONCLUSIONS: This method is a reliable, accurate, and cost-effective means of calculating SCHF distal fragment malrotation and warrants clinical application.

"Floating total knee": ipsilateral periprosthetic fractures of the distal femur and proximal tibia after total knee arthroplasty.

UNLABELLED: Currently, there are more than 300000 primary total knee arthroplasty (TKA) performed annually in the United States. It is estimated that 0.3% to 2.5% of these patients will sustain a periprosthetic fracture in association with a TKA [Haidukewych GJ, Jacofsky DJ, Hanssen AD. Treatment of periprosthetic fractures around a total knee arthroplasty. J Knee Surg 2003;16:111]. The first report of a periprosthetic fracture involving a TKA occurred in 1977 [Callaghan JJ. Periprosthetic fractures of the acetabulum during and following total hip arthroplasty. Instr Course Lect 1998;47:231]. The majority of periprosthetic fractures associated with a TKA are distal femoral fractures [Berry D. EPIDEMIOLOGY: hip and knee. In: Callaghan J, Duncan C, editors. Periprosthetic fractures after major joint replacement. Philadelphia: WB Saunders; 1999. p. 183]. Periprosthetic tibial fractures are rare and usually involve the medial tibial plateau in the presence of a loose component [Rand JA, Coventry MB. Stress fractures after total knee arthroplasty. J Bone Joint Surg Am 1980;62:226, Hanssen AD, Stuart MJ]. Treatment of periprosthetic tibial fractures. Clin Orthop 2000; p. 91]. The following case report describes the management of simultaneous ipsilateral distal femoral and proximal tibial periprosthetic fractures associated with a TKA. The patient was informed that data concerning the case would be submitted for publication. To our knowledge, this "floating total knee" injury has not been previously reported.