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Background With the ubiquity of digital radiographs, the use of digital templating for arthroplasty has become commonplace. Although improved accuracy with digital radiographs and magnification markers is assumed, it has not been shown. Questions/PurposesWe wanted to (1) evaluate the accuracy of magnification markers in estimating the magnification of the true hip and (2) determine if the use of magnification markers improves on older techniques of assuming a magnification of 20% for all patients. Methods Between April 2013 and September 2013 we collected 100 AP pelvis radiographs of patients who had a THA prosthesis in situ and a magnification marker placed per the manufacturer's instructions. Radiographs seen during our standard radiographic review process, which met our inclusion criteria (AP pelvic view that included a well-positioned and observed magnification marker, and a prior total hip replacement with a known femoral head size), were included in the analysis. We then used OrthoView TM software program to calculate magnification of the radiograph using the magnification marker (measured magnification) and the femoral head of known size (true magnification). Results The mean true magnification using the femoral head was 21% (SD, 2%). The mean magnification using the marker was 15% (SD, 5%). The 95% CI for the mean difference between the two measurements was 6% to 7% (p \ 0.001). The use of a magnification marker to estimate magnification at the level of the hip using standard radiographic techniques was shown in this study to routinely underestimate the magnification of the radiograph using an arthroplasty femoral head of known diameter as the reference. If we assume a magnification of 20%, this more closely approximated the true magnification routinely. With this assumption, we were within 2% magnification in 64 of the 100 hips and off by 4% or more in only four hips. In contrast, using the magnification marker we were within 2% of true magnification in only 20 hips and were off by 4% or more in 59 hips. Conclusion We found the use of a magnification marker with digital radiographs for preoperative templating to be

Background Various landmarks can guide tibial component rotational alignment in routine TKA, but with the deeper tibial resection levels common in complex primary and revision TKAs, it is unknown whether these landmarks remain reliable. Questions/purposes We asked whether three techniques for determining tibial component rotation based on local anatomic landmarks are reliable deeper tibial resection levels. Patients and Methods The femoral transepicondylar axis was identified by three independent reviewers on MR images of knees from 24 men and 24 women and transposed at a traditional tibial resection level and at the level of the proximal, middle, and distal parts of the proximal tibiofibular joint. Three axes were drawn on axial slices at these levels: the geometric center of the tibial plateau to the medial 1 . 3 of the tubercle, the posterior condylar line of the tibia, and the largest mediolateral dimension of the tibia. These lines were compared with the transposed femoral epicondylar axis line. Results The posterior condylar line of the tibia is the least variable local landmark for tibial component positioning at deep resection levels. Conclusions Assuming the normal posterior condylar line of the tibia is visible at revision, setting the tibial component at 10°external rotation with respect to the posterior condylar axis of the tibia gets the tibial component within 10°of proper rotation in 86% to 98% of patients, even to the distal part of the proximal tibiofibular joint. The experienced surgeon then can adjust this position based on cues from an assortment of other axes.

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Controversy exists concerning pin placement for supracondylar humerus fractures in children. Both crossed pin and lateral only pin configurations have shown good results; however, prospective studies are lacking. We present a prospective, surgeon-randomized study comparing crossed pin (group A, n = 20) versus preferential lateral only pin (group B, n = 20) fixation for displaced supracondylar humerus fractures. There was no difference in Baumann's angle (P>0.75), the humerotrochlear angle (P>0.85), or final elbow range of motion (P>0.25). Both groups had stable reductions and clinically normal alignment. The only complication in both groups was a transient ulnar nerve irritation, despite no intraoperative evidence of nerve violation with a nerve stimulator. One patient in each group required modification of the operative plan. In group B, one patient had a medial pin inserted because of medial comminution extending proximally limiting available lateral pin placement. In group A, the surgeon elected to use lateral pins only because of an obviously subluxating ulnar nerve. In conclusion, we recommend orthopedic surgeons treating unstable pediatric supracondylar humerus fractures be facile with both medial and lateral pin placement.