Acromion spacer

1. A prosthesis assembly for use with a scapula, comprising:

an acromion spacer unit configured such that when mounted on a scapula, the acromion spacer unit is separate from any component implanted at a midpoint of a glenoid fossa of the scapula such that a force against the mounted acromion spacer unit is not transferred to the component implanted at the midpoint;

a first articulation surface on an inferior surface of the acromion spacer unit;

a bone contacting surface on a superior surface of the acromion spacer unit; and

a bone mounting member extending sideways from the acromion spacer unit and oriented such that when the acromion spacer unit is mounted on a scapula, the bone mounting member extends medially from the acromion spacer unit through an upper portion of the glenoid fossa and the acromion spacer unit is positioned at a height above a height of the midpoint of the glenoid fossa of the scapula.

2. The assembly of claim 1 , wherein the acromion spacer unit further comprises:

a base portion from which the bone mounting member extends, the base portion including a coupling member configured to couple with a complementary coupling member on a spacer component which defines the bone contacting surface.

3. The assembly of claim 2 , wherein the base portion coupling member comprises a dovetail coupling member.

4. The assembly of claim 1 , further comprising:

a glenoid prosthesis unit configured such that when the acromion spacer unit is mounted on the scapula and the glenoid prosthesis unit is implanted in the glenoid fossa, the acromion spacer unit component is disconnected from the glenoid prosthesis unit.

5. The assembly of claim 1 , further comprising:

a humeral prosthesis.

6. A prosthesis kit for use with a scapula, comprising:

a plurality of acromion spacer unit components, the plurality of acromion spacer unit components providing

at least one first articulation surface of an acromion spacer unit configured to be movable with respect to any component located at a midpoint of a glenoid fossa of a scapula when the acromion spacer unit is mounted on the scapula such that a force against the mounted acromion spacer unit is not transferred to the component located at the midpoint,

at least one bone contacting surface on a surface opposite the at least one first articulation surface of the acromion spacer unit, and

at least one bone mounting member configured to extend sideways from the acromion spacer unit through an upper portion of the glenoid fossa when the acromion spacer unit is positioned above the midpoint of the glenoid fossa of the scapula.

7. The kit of claim 6 , further comprising:

at least one glenoid prosthesis unit, the at least one glenoid prosthesis unit configured such that when a first of the plurality of acromion spacer unit components is mounted on the scapula and a first of the at least one glenoid prosthesis units is implanted in a glenoid fossa, the first of the plurality of acromion spacer unit components is disconnected from the first of the at least one glenoid prosthesis units.

8. The kit of claim 7 , further comprising:

at least one humeral prosthesis unit.

9. The kit of claim 6 , wherein:

the at least one first articulation surface is defined by a base portion;

the base portion includes a first coupling member; and

the at least one bone contacting surface comprises a plurality of bone contacting surfaces, each of the plurality of bone contacting surfaces defined by a respective one of a plurality of spacer components.

10. The kit of claim 9 , wherein the first coupling member comprises a dovetail coupling member.