Multi-component joint prosthesis with increased wall flexibility facilitating component assembly

A joint prosthesis comprising first and second cup-shaped components for being assembled together, the assembly of said components requiring the application thereto of assembly forces, said first component being a segmented open shell including a wall defining part spherical inner and outer surfaces, said segmented open shell has a face and a plane of symmetry, the face of said segmented open shell is defined by (i) a first planar surface substantially perpendicular to said plane of symmetry, (ii) a second planar surface substantially perpendicular to said plane of symmetry and angularly aligned to said first planar surface, (iii) a pair of third planar surfaces disposed on opposite sides of the plane of symmetry and defining a plane substantially perpendicular to said plane of symmetry and inclined at an angle with respect to said first planar surface, (iv) a pair of first curved surfaces disposed on opposite sides of the plane of symmetry and defining a portion of a cylinder aligned substantially perpendicular to said plane of symmetry and tangent to said second and third planar surfaces and (v) a pair of second curved surfaces disposed on opposite sides of the plane of symmetry and defining a portion of a second cylinder aligned substantially perpendicular to said plane of symmetry and tangent to aid first and third planar surfaces;

• wherein the alignment of said surfaces relative to one another increases the flexibility of the wall and facilitates assembly of said components;
• and said segmented open shell having anterior and posterior portions and wherein said second through fifth surfaces produce protrusions at the anterior and posterior inferior portions of said segmented open shell.

A hip joint prosthesis comprising a generally semi-hemispherical acetabular cup and a generally semi-hemispherical bearing liner each having a face, anterior, posterior and inferior wall portions and said bearing liner for being inserted into and removed from said acetabular cup, said acetabular cup and said bearing liner each being a segmented open shell aligned for increasing the flexibility of said anterior and posterior wall portions which facilitates insertion and removal of said bearing liner into and out of said acetabular cup, wherein said acetabular cup and said plastic bearing liner each have a plane of symmetry and each said face having superior and inferior portions, said superior face portion of said cup and said liner each being defined by a first planar surface substantially perpendicular to said plane of symmetry and said inferior face portion of said cup and said liner each being defined by:

• (i) a second planar surface substantially perpendicular both to said plane of symmetry and to said first planar surface, (ii) a pair of third planar surfaces disposed on opposite sides of said plane of symmetry and defining a plane substantially perpendicular to said plane of symmetry and inclined at an angle with respect to said first planar surface, (iii) a pair of first curved surfaces disposed on opposite sides of the plane of symmetry and defining portions of a cylinder aligned substantially perpendicular to said plane of symmetry and tangent to said second and third planar surfaces, and (iv) a pair of second curved surfaces disposed on opposite sides of said plane of symmetry and defining portions of a second cylinder aligned substantially perpendicular to said plane of symmetry and tangent to said first and third planar surfaces;
• and said cup and liner each have anterior and posterior portions and wherein said second and third planar surfaces and said first and second curved surfaces produce protrusions at said anterior and inferior portions.

A hip joint prosthesis component comprising a generally semi-hemispherical acetabular cup having anterior, posterior and inferior wall portions, said acetabular cup being a segmented open shell for increasing the flexibility of said anterior and posterior wall portions wherein said acetabular cup has a plane of symmetry and a face having superior and inferior portions, said superior face portion defined by a first planar surface substantially perpendicular to said plane of symmetry and said inferior face portion defined by:

• (i) a second planar surface substantially perpendicular to said plane of symmetry and aligned at an angle to said first planar surface and generally forming a right angle therewith, (ii) a pair of third planar surfaces on opposite sides of said plane of symmetry and defining a plane substantially perpendicular to said plane of symmetry and inclined at an angle with respect to said first planar surface, (iii) a pair of first curved surfaces on opposite sides of said plane of symmetry and defining portions of a cylinder aligned substantially perpendicular to said plane of symmetry and tangent to said second and third planar surfaces, and (iv) a pair of second curved surfaces on opposite sides of said plane of symmetry and defining portions of a cylinder aligned substantially perpendicular to said plane of symmetry and tangent to said first and third planar surfaces;
• and said acetabular cup having anterior and posterior portions and wherein said second and third planar surfaces and said first and second cylindrical surfaces produce protrusions at said anterior and posterior portions.

A hip joint prosthesis component comprising a generally semi-hemispherical bearing liner having anterior, posterior and inferior wall portions, said bearing liner being a segmented open shell for increasing the flexibility of said anterior and posterior wall portions wherein said bearing liner has a plane of symmetry and a face having superior and inferior portions, said superior face portion defined by a first planar surface substantially perpendicular to said plane of symmetry and said inferior face portion defined by:

• (i) a second planar surface substantially perpendicular both to said plane of symmetry and to said first planar surface, (ii) a pair of third planar surfaces on opposite sides of the plane of symmetry and defining a plane substantially perpendicular to said plane of symmetry and inclined at an obtuse angle with respect to said first planar surface, (iii) a pair of first curved surfaces on opposite sides of said plane of symmetry and defining portions of a cylinder aligned substantially perpendicular to said plane of symmetry and tangent to said second and third planar surfaces, and (iv) a pair of second curved surfaces on opposite sides of said plane of symmetry and defining portions of a cylinder aligned substantially perpendicular to said plane of symmetry and tangent to said first and third planar surfaces;
• and said plastic bearing liner having anterior and posterior portions and wherein said second and third planar surfaces and said first and second curved surfaces produce protrusions at said anterior and posterior portions.