An implantable device (20) includes a first anchor (22), configured to be implanted inside a first bone (24), and a second anchor (26), configured to be implanted inside a second bone (28), adjacent to the first bone. A cord (30) connects the first and second anchors. A shock absorber (42) contained within at least one of the first and second anchors is coupled to the cord so as to deform in response to a force exerted on the cord. The shock absorber may also include a force adjuster (48). The device may include an adjustment mechanism (44), which is operable, after implantation of the first and second anchors in the first and second bones, to adjust a length of the cord extending between the first and second anchors.
