Intramedullary humeral replacement: an evolving design

Abstract

Introduction: Total humeral replacement is used to reconstruct the upper limb after tumour resection, while in cases of complex revisions for non-oncological reasons, using tumour prosthesis implants will lead to an otherwise avoidable further bone resection and violation of the surrounding tissues. This report describes a design evolution in three non-oncological cases, where a total humeral resection to perform a total humeral replacement is avoided and instead the simultaneous shoulder and elbow replacements were connected via custom-made intramedullary linkages.

Methods: Three cases of simultaneous shoulder and elbow replacement were performed for complex revision situations over a period of 42 months. They were performed while preserving as much humeral bone stock as possible, with the design changing from a big intramedullary connecting stem to a smaller component when performing an Intramedullary Humeral Replacement (IMHR), allowing preservation of more bone and soft tissue attachment than if a total humeral replacement were performed.

Results: None had any neurovascular complication or any further revision for the humeral replacement, or the shoulder and elbow components.

Discussion: We have showed three examples of an evolving design aiming to preserve as much of the anatomy as possible to help in decreasing the surgical impact and invasiveness of this procedure, while doing less bone resection and sacrificing less of the soft tissue attachments.

Keywords: Elbow replacement; Endo-prosthetic replacement; Humeral replacement; Megaprosthesis; Shoulder replacement.

Figure 1.

This figure shows the pre-operative radiograph for the first case, demonstrating a complex situation with significant loosening around the stem of a previous endo-prosthetic replacement, with a poor bony envelope remaining.

Figure 2.

This figure shows the pre-operative radiograph for the second case, which also shows significant loosening around the endo-prosthetic stem with a peri-prosthetic fracture and a broken elbow prosthetic hinge.

Figure 3.

This figure shows the pre-operative radiograph for the third case, demonstrating an elbow replacement and a shoulder hemi-arthroplasty on the same side, with poor bone quality, loosening, and impending fracture.

Figure 4.

The radiograph shows IMHR for the first case, and it illustrates preservation of mainly the proximal third of the humerus, with the usage of shoulder hemi-arthroplasty proximally and a large humeral body distally joined to an elbow replacement ulnar component.

Figure 5.

The radiograph shows IMHR for the second case, and it illustrates preservation of most of the proximal half of the humeral shaft with a shoulder hemi-arthroplasty proximally and a large humeral body distally joined to an elbow replacement ulnar component.

Figure 6.

The radiograph shows IMHR for the third case, and it illustrates preservation of most of the humeral shaft, which is bypassed by an intramedullary rod, while using a reverse shoulder replacement component proximally and a smaller distal humeral prosthetic body over an elbow replacement ulnar component.

Figure 7.

A front view clinical photograph for the third case showing active shoulder lateral abduction.

Figure 8.

A side view clinical photograph for the third case showing active shoulder forward flexion.

Figure 9.

A side view clinical photograph of the third case showing active shoulder lateral abduction.