Restoring Function and Stability with Humeral Bone Loss

How do surgeons reconstruct a shoulder when the patient has massive proximal humeral bone loss?

Massive humeral bone loss – whether from severe trauma, infection or a failed previous surgery – is one of the most daunting problems a shoulder surgeon can face. Standard humeral implants have historically been inadequate, leading to high rates of loosening and instability.

Srinivasan and colleagues followed 44 patients who received a modular Equinoxe^® Humeral Reconstruction Prosthesis (HRP) to see if it could provide a viable long-term solution for patients with massive humeral bone loss. This endoprosthesis was specifically designed to address the failure modes of older designs, using diaphyseal collars to achieve distal humeral fixation and rotational stability and using multiple sizes of anatomically shaped proximal bodies to restore deltoid wrapping, offering hope for patients who had otherwise exhausted their surgical options.

• Zero humeral loosening: Remarkably, at the two-year mark, there were no occurrences of humeral loosening requiring revision surgery.
• Significant motion gains: Patients saw substantial improvements in their ability to lift their arm, with forward elevation increasing by 28° (p=0.003).
• Meaningful pain relief: Average daily pain scores improved significantly, dropping to an average of 2.0 points on a 10-point scale (p<0.001).
• Stability achieved: The overall complication rate was 28%, where 9 of 20 complications were dislocations. All dislocations were managed successfully with closed reduction, without requiring revision surgery.
• Patient success: The majority of patients achieved clinically meaningful improvements across all outcome measures (56-81%) and range of motion measurements (67-75%).

Revision surgery in the setting of massive humeral bone loss often fails due to instability and loss of fixation of the humeral component. The HRP design utilizes a press-fit collar combined with a cemented stem to maximize time-zero stability, allowing for restoration of function and joint tensioning without the high revision rates associated with traditional endoprostheses or allograft-prosthetic composite techniques.

These findings are limited because the study is a retrospective case series with a small sample size, which is a common challenge when studying such a rare and complex procedure.