Set screws often do feature a head - very likely a hex fitting - but without a threadless section immediately below it (again, this is different to the length of unthreaded shank you’d typically find on a standard bolt). Because they often feature no protruding screw head in the traditional sense, true grub screws tend to be driven by means of a sunken internal recess at what is still generally referred to as the ‘head end’.

Alvis-Miranda HR, Farid-Escorcia H, Alcala-Cerra G, Castellar-Leones SM, Moscote-Salazar LR. Sacroiliac screw fixation: A mini review of surgical technique. J Craniovertebr Junction Spine. 2014;5(3):110.Vaidya R, Colen R, Vigdorchik J, Tonnos F, Sethi A (2012) Treatment of unstable pelvic ring injuries with an internal anterior fixator and posterior fixation: initial clinical series. J Orthop Trauma 26:1–8. https://doi.org/10.1097/BOT.0b013e318233b8a7

The intramedullary headless compression screw (IMCS) technique represents a reliable alternative to percutaneous Kirschner-wire and plate fixation with minimal complications. The loading protocol commenced with an initial nondestructive quasi-static ramp from 20 N preload to 200 N at a rate of 18 N/s, followed by progressively increasing cyclic loading in axial compression with a physiological profile of each cycle at a rate of 2 Hz [ 25]. Keeping the valley load at a constant level of 20 N, the peak load, starting at 200 N, was monotonically increased cycle by cycle at a rate of 0.05 N/cycle until catastrophic failure of the specimen [ 26, 27]. Data acquisition & analysis Group CCS demonstrated considerably higher stability in terms of fracture and torsional displacement compared to group RST

Headless Compression Screws Contraindications

Although group CCS revealed comparable results to RSV, it was associated with higher stability regarding cycles to predefined failure criteria Sagi H, Ordway N, DiPasquale T. Biomechanical analysis of fixation for vertically unstable sacroiliac dislocations with iliosacral screws and symphyseal plating. J Orthop Trauma. 2004;18(3):138–43.