Device for variable fixation of bone fragments

A device for bone fixation, comprising:

• a head portion, a tapered portion, and a shaft between the head portion and the tapered portion, the shaft comprising a distal portion, a middle portion and a proximal portion,
• wherein the distal portion of the shaft comprises a thread and having a maximum outer diameter DA and an inner core diameter DI,
• wherein the proximal portion of the shaft comprises a core comprising a biologically non-degradable material with a degradation rate BND and a diameter d;
• and
• a sleeve surrounding the core, the sleeve comprising a biologically degradable material with a degradation rate BD, the sleeve having a diameter Ds≤DA, whereby BD>BND.

A device for bone fixation, comprising:

• a head portion and a shaft, the shaft comprising a distal portion, a middle portion and a proximal portion,
• wherein the distal portion of the shaft comprises a thread and having a maximum outer diameter DA and an inner core diameter DI,
• wherein the proximal portion of the shaft comprises a core comprising a biologically non-degradable material with a degradation rate BND and a diameter d;
• and
• a sleeve surrounding the core, the sleeve comprising a biologically degradable material with a degradation rate BD, the sleeve having a diameter Ds≤DA, whereby BD>BND.