Headless Compression Screw 1.5 (extra small)
The headless compression screw (HCS) was first introduced in sizes of 2.4 mm and 3.0 mm. Now the family has been enlarged by an extra small version of 1.5 mm. Indications are fixation of intra- and extraarticular fractures and nonunions of small bones and small bone fragments, arthrodeses of small joints, osteochondral fractures, osteotomies, and avulsion fractures.
The HCS 1.5 works according to the same functional principle as for the existing 2.4 mm and 3.0 mm HCS: insertion, reduction and compression in separate steps. Controlled compression is achieved through a separate compression sleeve. The only difference is that the HCS 1.5 is not cannulated.
The shaft thread has a diameter of 1.5 mm and a head of 2.1 mm. The shaft thread length is progressive from 48 mm. The screw lengths advance from 826 mm in steps of 1 mm. A special compression sleeve is required for the HCS 1.5. An optional 1.8 mm drill bit for predrilling the head in hard bone is available.
Mechanical tests compared to the 1.5 mm cortex screw showed that the push-/pull-out performance is higher, torsion is about the same and maximum compression slightly higher for the same thread length when compared to the other HCS sizes.
A 22-year-old female with previous complex fractures of the base and head of the middle phalynx (proximal screws are from the previous fracture fixation) presented with a residual painful, deformed, and stiff DIP J. Joint arthrodesis planned.
Case provided by Robert Farnell, Leeds, UK
The arthrodesis was performed using the longest available screw. Note that despite this it has only just crossed the arthrodesis site (see Fg 2a-b)
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