RESUMO
BACKGROUND: Anatomic referencing in total knee arthroplasty places the femoral component flush to the anterior cortex while maintaining posterior condylar offset (PCO). The intent of this study was to evaluate how component position influences the femoral component size. METHODS: Digital surface models were created using 446 femora from an established computed tomography database. Virtual bone resections, component sizing, and component placement were performed assuming neutral (0°) flexion and neutral (3°) rotation relative to the posterior condyles. The appropriately sized femoral component, which had 2 mm of incremental size, was placed flush with the anterior cortex for optimal restoration of the PCO. Sizing and placement were repeated using 3 and 6° flexion and 0, 5, and 7° external rotation (ER). RESULTS: At 0° flexion, decreasing ER from 3 to 0° resulted in an average decreased anterior-posterior height (APH) of 1.9 mm, corresponding to a component size decrease of 1 for 88% of patients. At 7° ER, component size increased by an average of 2.5 mm, corresponding to a size increase for 80% of patients. Flexing the femoral component to 3° with ER at 3° resulted in a decrease in APH of 2.2 mm (1 size decrease in 93% of patients). At 3° flexion and 3° ER, 86% had the same component size as at 0° flexion and 0° ER. Increasing ER at 3° flexion increased APH by 1.2 mm at 5° and 3.1 mm at 7° on average, relative to 3° ER. Increasing flexion from 3 to 6° extended this effect. CONCLUSIONS: Flexion decreases the APH when the ER is held constant. The ER of the femoral component increases the APH across all tested flexion angles, causing an increase in the ideal femoral component size to maintain PCO. With anatomic referencing, alterations in femoral component positioning and subsequent changes in component size can be accounted for.
RESUMO
Finger amputations are commonly encountered. These may be revised in the emergency department (ED) or the operating room (OR). Previous studies have demonstrated the cost-effectiveness associated with procedures performed in the ED. Patient outcomes have not been described. We retrospectively reviewed patients who presented to our level 1 trauma center with a traumatic partial or complete finger amputation through flexor tendon zone I. All were treated with revision amputation performed in either the ED or the OR between January 2012 and December 2017. A total of 172 patient charts were included. Ninety-three of the revision amputations were performed in the ED, while 79 were performed in the OR. There was no difference in age, race, sex, having a manual labor job, medical comorbidities, or mechanism of injury between the groups. Compared with procedures performed in the ED, procedures performed in the OR had a higher rate of delayed healing, a longer stay in the hospital, and a higher referral to therapy postoperatively. Length of follow-up and number of follow-up visits were not statistically different based on location of procedure. There was no difference in post-procedural infection rate or need for revision procedure between the groups. Our data support the efficacy of performing revision amputation procedures in the ED. Recorded patient complications and subsequent treatment after revision amputations performed in the ED vs the OR were comparable. Those performed in the ED potentially decrease the burden placed on the patient and the health care system. [Orthopedics. 202x;4x(x):xx-xx.].
