FIELD OF DISCLOSURE

The present invention relates generally to an apparatus and device for securing a glenoid implant to a glenoid, and in particular, to an anchor with deformable portions that are adapted to form a cement-less connection with the glenoid.

BACKGROUND

In a healthy shoulder joint, the humeral head of the humerus interacts with the glenoid of the scapula to form a “ball and socket” joint. The humeral head abuts and articulates with the glenoid to allow a wide range of motion in the shoulder. In an unhealthy shoulder joint, the interaction between the glenoid and the humerus are compromised, requiring repair or replacement. Total shoulder replacement is one method used to replace shoulder joints that have been damaged beyond repair due to trauma or disease. Typically, a total shoulder replacement procedure includes providing a glenoid component and a humeral component that interact with each other at an articulating surface.

Conventionally, glenoid components have been designed as two-piece components made of plastic and metal. Due to difficulties in designing a mechanism to lock the two pieces together, the assembly can fail over time. Replacement of the glenoid component requires that the patient undergo an additional surgical procedure and be subjected to additional recovery time and costs. One-piece glenoid components have also been developed that fixate to a glenoid and provide an articulating surface for the humeral component. Bone cement is commonly used to secure the glenoid component to the glenoid for both two-piece and one-piece components.

U.S. Pat. No. 6,911,047 (Rockwood Jr. et al.) discloses a glenoid component having an anchor peg and stabilizing pegs to secure the glenoid component to a glenoid without the use of bone cement. The anchor peg disclosed in Rockwood Jr. et al. includes a body portion having a plurality of fins at a proximal end of the body portion. When the glenoid component is positioned within the glenoid and scapula, the fins provide resistance to removal forces on the glenoid component. The stabilizing pegs are positioned within the glenoid around the anchor peg to prevent movement of the body portion relative to the glenoid.

SUMMARY

The present invention is directed to a prosthesis with an anchor having deformable portions that engage with cortical bone at a glenoid.

In some embodiments, the present prosthesis is adapted to form a cement-less connection with a glenoid. The deformable portions are optionally structured for substantially unidirectional deformation. That is, the deformable portions resist deformation in the direction of removal. The anchor is optionally modular so that it is easily customized for patients of varying sizes. For example, different patients may have cortical bone of varying thicknesses and/or glenoids of varying depths.

In one embodiment, the present invention is a prosthesis that mechanically couples with both cancellous bone and cortical bone of a glenoid. The prosthesis includes a head portion comprising a rear surface and an articular surface, an anchor member, and a plurality of deformable fins extending radially outward from the anchor member. The anchor member includes a proximal end and a distal end. The proximal end is connected to the rear surface of the head portion. The plurality of deformable fins extend radially outward from the anchor member and include at least a first proximal fin adjacent to the rear surface of the head portion positioned to engage with the cortical bone. The plurality of deformable fins may also include at least one distal fin located proximate the distal end of the anchor member positioned to engage with the cancellous bone.

In another embodiment, the present invention is a prosthesis for securement to a glenoid and includes a head portion and an anchor. The head portion has a first surface and a second surface. The anchor extends from the first surface of the head portion and includes a proximal end connected to the first surface of the head portion, a distal end opposite the proximal end and a set of proximal fins. The set of proximal fins extend radially from the proximal end of the body portion. The anchor may also include a set of distal fins extending radially from the distal end of the body portion. The anchor is configured to engage the glenoid.

In an alternative embodiment, the present invention is an implant positionable between a glenoid and a humeral component. The implant includes a head portion and an anchor. The head portion has a first surface engageable with the glenoid and a second surface engageable with the humeral component. The anchor extends substantially perpendicularly from the first surface of the head portion and has a first end attached to the first surface, a second end opposite the first end, and a first set of flexible flanges positioned proximate the first end of the anchor. The anchor may also include a second set of flexible flanges positioned proximate the second end of the anchor.

The present invention is also directed to a method of fixating a prosthesis to a glenoid. The method includes aligning an anchor of the prosthesis with a bore formed in the glenoid and inserting the anchor in the bore such that a first surface of the prosthesis engages the glenoid. The anchor includes a first deformable fin and a second deformable fin. The first deformable fin is implanted within cancellous bone and the second deformable fin is implanted proximate cortical bone.

Terminology such as “first,” “second,” “third,” etc., is used herein to designate particular components being described. Because various components of the embodiments described herein can be positioned in a number of different orientations and in a number of different sequences, this terminology is used for the purposes of illustration and is not intended to be read in a restrictive manner.

