ObjectivesOne commonly used rat fracture model for bone and mineral research is a closed mid-shaft femur fracture as described by Bonnarens in 1984. Initially, this model was believed to create very reproducible fractures. However, there have been frequent reports of comminution and varying rates of complication. Given the importance of precise anticipation of those characteristics in laboratory research, we aimed to precisely estimate the rate of comminution, its importance and its effect on the amount of soft callus created. Furthermore, we aimed to precisely report the rate of complications such as death and infection.MethodsWe tested a rat model of femoral fracture on 84 rats based on Bonnarens’ original description. We used a proximal approach with trochanterotomy to insert the pin, a drop tower to create the fracture and a high-resolution fluoroscopic imager to detect the comminution. We weighed the soft callus on day seven and compared the soft callus parameters with the comminution status.ResultsThe mean operating time was 34.8 minutes (sd 9.8). The fracture was usable (transverse, mid-shaft, without significant comminution and with displacement < 1 mm) in 74 animals (88%). Of these 74 usable fractures, slight comminution was detected in 47 (63%). In 50 animals who underwent callus manipulation, slight comminution (n = 32) was statistically correlated to the amount of early callus created (r = 0.35, p = 0.015). Two complications occurred: one death and one deep infection.ConclusionsWe propose an accurate description of comminution and complications in order to improve experiments on rat femur fracture model in the field of laboratory research.Cite this article: Bone Joint Res 2013;2:149–54.

To evaluate the coding practices of hand surgeons in the American Society for Surgery of the Hand with respect to practice compensation structure using common, representative hand surgery cases. Methods: We developed a survey of demographic factors and 4 commonly encountered hypothetical hand surgery cases. This survey was emailed to the members of the American Society for Surgery of the Hand. Respondents were asked to code these cases using prepopulated applicable Current Procedural Terminology codes or any other codes of their choosing. The membership responses were then compared with those of 3 independent orthopedic coders. Results: Of the 4,477 invitations sent, a total of 421 (9.4%) respondents completed the survey. There was notable heterogeneity in the Current Procedural Terminology code choices for the trapeziectomy and distal radius fracture cases. Physicians with a collections-based model coded for significantly higher work-related value units on average compared with the fixed salarye and relative value unitebased physicians for the trapeziectomy case (14.41 vs 13.65 and 13.67, respectively; P < .05). The 3 independent coders all chose a single Current Procedural Terminology code for the carpal tunnel release, distal radius fracture, and scaphoid nonunion cases. The percentages of physician responses that selected only these codes were 84.6% (carpal tunnel release), 61.0% (distal radius fracture), and 73.6% (scaphoid nonunion). Physicians were less likely to code in line with the independent coders for the distal radius fracture case compared with other cases, particularly those physicians with a collections-based model. Conclusions: The compensation model may be associated with coding practices for more complicated hand cases. The additional work-related value units potentially billed can quickly accumulate for frequently performed procedures. This wide variation supports a need for more frequent and accessible communication and education on coding practices in hand surgery. Clinical relevance: Improved communication and education regarding appropriate coding practices as well as easily accessible reference material may assist in minimizing coding discrepancies for surgical hand procedures.