Why do standard length humeral stems get the short end of the stick?

As pointed out in a prior post (see this link), short stemmed humeral components have been designed to "solve the problems" of a standard length stem, which are said to include intraoperative humeral fractures, stem loosening, periprosthetic fractures, stress shielding, and difficulties with revision surgery. Yet the overall failure rate published for standard length stems is less than half a percent.

For over four decades, this has been our experience as well: no problems with intraoperative fractures or stem loosening (except in cases of infection) and very rare instances of periprosthetic fracture, stress shielding or difficulties in revising the stem. 

The key to avoiding the issues that have been attributed to standard length stem is selecting a stem diameter that will give a low diaphysial filling ratio and fixing it with impaction autografting.

Here are typical results for two shoulders in the same patient. The x-ray of the right shoulder is a 27 year followup

The x-ray of the left shoulder is an 11 year followup.

Each shows maximal bone preservation, no stress shielding and no evidence of loosening. 

In contrast to the situation with short stems (see this link), the standard length stem minimizes the risk of malpositioning and does not require grit blasted or porous coated surfaces for fixation (which can complicate stem removal).

Comment: It appears that much of the "bad rap" placed on standard length stems comes from problems related to oversized implants, which risk improper positioning, fracture and stress shielding as shown below

In terms of cost, safety, and effectiveness, the smooth, relatively thin, standard length stems appear to have advantages over many currently marketed short stemmed humeral components. Yet, for reasons known only to them, companies are choosing not to continue to provide the smooth, standard length stems.

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Here are some videos that are of shoulder interest
Shoulder arthritis - what you need to know (see this link).
How to x-ray the shoulder (see this link).
The ream and run procedure (see this link).
The total shoulder arthroplasty (see this link).
The cuff tear arthropathy arthroplasty (see this link).
The reverse total shoulder arthroplasty (see this link).
The smooth and move procedure for irreparable rotator cuff tears (see this link).
Shoulder rehabilitation exercises (see this link).

How should the humeral component be secured in reverse total shoulder arthroplasty?

Are Short Press-Fit Stems Comparable to Standard Length Cemented Stems in Reverse Shoulder Arthroplasty? A Prospective Randomized Clinical Trial

These authors note "there has been a trend away from standard length cemented humeral implants to press-fit stems, and recently to shorter stem implants, " but minimal literature to support this trend.

The goal of their study was to compare clinical outcomes and implant migration between cemented standard length humeral stems and press-fit short stems using radio-stereometric analysis in 41 shoulders randomized to receive each of the two stems. 

Following surgery, the shoulders were imaged sequentially with stereo x-rays.

At six months, one year, and two years postoperatively, press-fit short stems migrated significantly more than cemented stems along the superior-inferior translation axis.

They noted stress shielding at the proximal medial calcar (solid arrow), and increased sclerosis at the medial metaphyseal diaphyseal junction (dashed arrow) with the use of press-fit stems (below).

The authors did not detect a significant difference in the clinical outcomes between the two types of stem fixation.

Comment: The are many different designs of reverse humeral stems with different approaches to lateralization and fixation. 

Our favored approach is shown in this link. It enables secure prothesis alignment in the proximal humerus so that subsidence is minimized

and cementless fixation of a relatively thin stem using impaction autografting. 

so that stress shielding is avoided.

See also Avoiding stress shielding around the humeral implant - are short stems the answer or the problem? 

Follow on twitter: https://twitter.com/shoulderarth

Follow on facebook: https://www.facebook.com/frederick.matsen

Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

How you can support research in shoulder surgery Click on this link.

Here are some videos that are of shoulder interest

Shoulder arthritis - what you need to know (see this link)

Shoulder arthritis - x-ray appearance (see this link)

The smooth and move for irreparable cuff tears (see this link)

The total shoulder arthroplasty (see this link).

The ream and run technique is shown in this link.

The cuff tear arthropathy arthroplasty (see this link).

The reverse total shoulder arthroplasty (see this link).