Evaluating the design modifications of an intramedullary forearm nail system: a cadaver study

Abstract

Background Current orthopaedic practice requires a forearm nail that is length and rotationally stable and which can restore functional anatomy. A forearm nailing system was designed based on clinical need. This nailing system features unique designs and locking holes that offer a larger approach and escape angle for ease of interlocking. The aim of the present study was to test the prototype and evaluate the design changes in cadaver bones. Methods A cross-sectional cadaveric study, including ten cadavers with normal forearm anatomy (n = 20 forearms) was conducted. Both forearms of the cadavers were used to evaluate the locking times and exposure time during i) insertion; ii) locking; and iii) removal of the nails, resulting in the evaluation of a total of 40 procedures. All nails were assessed for insertions of interlocking screws. Results The nail was successfully inserted into 38 bones. Inserted nails were available for locking (n = 38), and all locking attempts at both driving ends (n = 38, 100%), as well as the non-driving ends (n = 76, 100%), were successful. Freehand locking at the non-driving end of the nail (38 cases, 76 locking holes) took a median of 44.5 seconds (interquartile range [IQR] 33.0–59.0), while the number of exposures ranged from 2 to 12 with a median of 5.5 exposures (IQR 4.0–8.0). The freehand locking procedure’s exposure time was 0.09 minutes (IQR 0.07–0.23). Conclusion The proposed forearm intramedullary nail design modifications allowed for successful implan- tation, interlocking and removal of nails in both radius and ulna cadaver bones, with acceptable radiation exposure. Level of evidence Level 5