Overstuffing - what does the published literature get right?

In the prior post, I reviewed the concept of overstuffing - a limited volume with an excessive volume of stuff put in it.

Once more, it is emphasized that in anatomic shoulder arthroplasty, the volume available in the shoulder joint is not the "premorbid" volume, but rather the volume available at surgery after the osteophytes have been removed and after the soft tissue releases have been carried out. Attempting to restore premorbid anatomy to a shoulder with diminished volume will predictably cause a tight shoulder.

The volume of the components put into this space relates in part to the volume of the implants themselves (the chart below shows the humeral head volume in relation to the diameter of curvature and the thickness of the humeral head in a typical arthroplasty system)

but also to the position in which the component is placed. Shown below is overstuffing related to an insufficient humeral neck cut (red = actual, green = desired).

I found 14 English language articles containing the terms "overstuffing" and "shoulder" published since the original description of overstuffing.

The preponderance of these articles proposed the importance of two-dimensional radiographs to assess postoperative humeral positioning in relation to "premorbild" anatomy, failing to recognize that overstuffing is a three-dimensioinal issue related to the relationship of the intraoperative volume of the glenohumeral joint and the volume of the components added to this space.

However, one article pointed out that "anatomic' reconstruction is less important than good postoperative glenohumeral kinematics. It needs to be read by surgeons performing shoulder arthroplasty. 

The authors of How anatomic should anatomic total shoulder arthroplasty be? Evaluation of humeral head reconstruction with the best-fit circle demonstrated that "utilization of the best-fit circle in GHOA may lead to excessive humeral lateralization in aTSA." "This method of guiding humeral reconstruction and the addition of a 4-mm glenoid component resulted in a mean humeral lateralization of approximately 6.4 mm. The humeral lateralization was 7 mm or greater in one-third of cases. This is especially relevant in the context of standard anatomic glenoid preparation, which typically involves minimal bone reaming and the addition of an onlay glenoid which contributes to humeral lateralization. Joint line and humeral lateralization require balancing the benefits of improved stability and deltoid efficiency against the risks of rotator cuff over-tensioning and increased glenoid component loading, which may compromise early subscapularis repair healing and contribute to long-term rotator cuff and glenoid component failure. The available evidence and the findings of our study suggest that efforts to reconstruct the proximal humerus in aTSA performed using the best-fit circle as a guide should be considered with caution. The morphological bone changes and associated soft tissue contracture patterns of advanced GHOA need to be considered on a case by case basis in order to appropriately reconstruct anatomy, restore glenohumeral kinematics and function, and optimize survivorship of aTSA."

While the volume of the glenohumeral joing cannot be directly measured at surgery, the adequacy of the joint volume for a given set of trial implants can be inferred from the range of glenohumeral motion 

Here are the rest of the articles that focus on two-dimensional restoration of the "premorbid anatomy".

Geometrical analysis of Copeland surface replacement shoulder arthroplasty in relation to normal anatomy

The Copeland resurfacing humeral head implant does not restore humeral head anatomy. A retrospective study

Radiographic assessment of prosthetic humeral head size after anatomic shoulder arthroplasty

Assessment of the Anatomic Neck as an Accurate Landmark for Humeral Head Resurfacing Implant Height Placement

Results and limitations of humeral head resurfacing: 105 cases at a mean follow-up of 5 years

Low inter-observer agreement among experienced shoulder surgeons assessing overstuffing of glenohumeral resurfacing hemiarthroplasty based on plain radiographs

Overstuffing in resurfacing hemiarthroplasty is a potential risk for failure

 

Does computerized CT-based 3D planning of the humeral head cut help to restore the anatomy of the proximal humerus after stemless total shoulder arthroplasty? These authors concluded that restoration of proximal humeral anatomy with stemless anatomic total shoulder using computed tomography-based 3D planning was not precise. A poorly performed humeral head cut was the main reason for overstuffing, which was seen in 88% of the cases with inaccurate restoration of premorbid proximal humeral anatomy. Preoperative small humeral head diameter, low humeral head height, and varus-angulated head neck angle were risk factors for poor restoration of premorbid proximal humeral anatomy with stemless TSA.

Extra-short humeral heads reduce glenohumeral joint overstuffing compared with short heads in anatomic total shoulder arthroplasty

Best-Fit Circle for the Replication of Humeral Head Anatomy in Total Shoulder Arthroplasty

The impact of glenoid parameters and implant overstuffing on functional outcomes of shoulder hemiarthroplasty in patients with glenohumeral joint arthritis

Radiographic comparison of eccentric stemmed vs. concentric stemless prosthetic humeral head positioning after anatomic total shoulder arthroplasty

A reproducible method for evaluating the degree and direction of overstuffing of the humeral head component in anatomic total shoulder arthroplasty

The shoulder is not a two dimensional thing in FlatLand with the arm fixed at the side

The Shoulder is a Three-Dimensional Structure that Moves in Three Dimensions

Note the patagial bars on the shoulders of this red tailed hawk. 

Montlake

2024

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

Overstuffing (sur-rembourrage).

Overstuffing is simply defined as putting too much stuff in a limited space. 

It will be experienced by some during the coming Thanksgiving Holiday when the taste and fragrance of turkey fresh out of the oven 

will cause the celebrants to put too much in the limited space of their stomach.

Overstuffing was experienced by Alice in Wonderland when she ate a cookie labeled "Eat Me": "“Curiouser and curiouser!” cried Alice (she was so much surprised, that for the moment she quite forgot how to speak good English). “Now I’m opening out like the largest telescope that ever was! Good-bye, feet!” (for when she looked down at her feet, they seemed to be almost out of sight, they were getting so far off)."

Another common example of overstuffing is the compartmental syndrome which in a 1979 New England Journal of Medicine article (Compartmental Syndromes) we indicated that: "The compartmental syndrome is a condition in which increased pressure within an anatomic space compromises the circulation and function of the contents. The two prerequisites for this syndrome are an envelope of limited compliance (such as fascia, skin, plaster cast or dressings) and a cause for the increased volume within the envelope (such as bleeding or increased net capillary filtration)."

Thirty years ago in1994 we provided the first analysis of overstuffing in shoulder arthroplasty in the book Practical Evaluation and Management of the Shoulder (freely available here) along with its effect on shoulder motion.

   

Currently, many surgeons focus on reconstructing an "anatomic" arthroplasty "recreating premorbid anatomy". However, most arthritic shoulders have had a decreased joint volume for years prior to surgery. So unless the surgeon recreates premorbid joint volume, an anatomic arthroplasty will overstuff the articulation resulting in stiffness.

For this reason, we aim to conduct a kinematic, rather than an "anatomic" arthroplasty by assuring that, with the trial components in place, the shoulder has the desired range of motion

And document the motion with a "parting shot" photograph included in the operative note to show the patient that "it will go". 

In summary, avoiding the consequences of overstuffing requires that the volume of the contents of the space are appropriate for the volume of the space. The arthroplasty surgeon has some opportunity to increase the volume of the space by soft tissue releases; the surgeon has a lot of control over the volume of what she or he puts in the space. 

All's well as long as the shoulder has a balance of mobility and stability.

There's even a song entitled "Too Much Stuff"

Stuffing in preparation for the mating season.

Sooty Grouse

Mt Rainier 

July 2024

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

Fatal failures from failing to learn from failure

 

Soon after Anne and I arrived in Seattle, we became hooked on alpine climbing.

Three of our favorite climbs were:

The Inspiration Glacier Route on El Dorado

The Kautz Glacier Route on Mt. Rainier

and 

The West Ridge of Mt. Stuart

It occured to me that alpine climbing was similar to surgery in many ways: it is rewarding, it is technical, and it turns out well most of the time.

 

Also, like climbers, surgeons often do not learn from past failures.

My friend, Colton Bramson, loaned me a book last night called Accidents in North American Climbing 2023. What stuck me as I paged through this book was that a substantial number of fatalities occurred during rappelling. For the non-climbers among you, rappelling is a standard method of descending from a climb in which the climber slides down a rope that is fixed to an anchor.

In contrast to climbing up (where the climber is supported by his/her hands and feet), in rappelling the climber is completely dependent on (1) the anchor fixed to the rock or snow, (2) the link between the anchor and the rope (usually a combination of a carabiner and webbing or cord sling), (3) the rope (passed through  the anchor system so that the ends are of equal length with large knots at the end of each one), (4) the climber's harness, and (5) the link between the harness and the rope (such as a jumar). The technique of getting it right is shown in this link.  

As can easily be seen (as is the case in surgery) there are many points of potential failure:  anchor, carabiner, sling, harness, jumar and the rope (e.g. sliding off the end of the rope). 

Causes of fatal rappel falls have been well documented:

2004 Devils Tower — Fatal rappel error - no knots at the end of the rope 

2006: Sinks Canyon — Fatal fall while rappelling - no knots at the end of the rope

2016: Indian Creek — Uneven rope ends, no knots at the end of the rope

2017: Shelf Road — Fatal rappel error - improper set up of rappel system

2020: 6 rappel-anchor failures, 3 of them fatal 

2022: Joshua Tree (broken sling) - fatality

          Tahquitz (broken sling) - fatality

          Mt. Evans (fell while pulling rope after rappel) - fatality 

In spite of these examples of fatal errors from which climbers could learn, there were 8 known rappelling fatalities in 2023.

Accidents in North American Climbing sought to determine the cause of each failure, even when complete information was not available, and to suggest what could have been done to prevent the failure

45 yo female, Auburn Quarry-only one end of the rope passed through her belay device=>make sure both ends of the rappel rope are passed through the device

51 yo female, Joshua Tree-failure of old anchor and weathered sling=>avoid using anchor systems placed by prior climbers unless they are solid and in mint condition, take time to place new anchor system

22 yo female, Mt. Evans-fall while retrieving rappel rope=>make sure footing is secure and/or that the retrieving climber is anchored so that the act of rope retrieval does not cause a fall

58 yo female, El Dorado Canyon-one end of rope pulled through anchor=>tie knots in the end of each rope strand

two 67 yo males, Glacier National Park-hastily placed anchor pulled from rock=>take time to assure that anchor is solid and redundant

44 yo male, Leavenworth-poor anchor placement leading to anchor failure=>take time to assure that anchor is solid and redundant

33 yo female, Tahquitz Rock-failure of old anchor and weathered sling=>avoid using anchor systems placed by prior climbers unless they are solid and in mint condition, take time to place new anchor system

It is apparent that the American Alpine Club provides a great example of causal modeling. In each case, they sought to determine the counterfactual - what could have been done differently to prevent the rappelling accident - even in cases where complete information was not available.  In addition to the analyses of individual fatalities, they publish their results in their annual publication, Accidents in North American Climbing, so that all climbers have access to the results.

This a perfect example of learning from a relative small number of failures in a space - like orthopaedic surgery - where the great majority of cases are successful (see this link)

For more learning from failure in the mountains, see When Everest Climbers Die Because of Poor Decisions.

Surgery, like climbing, is usually wonderful, 

but past failures contain lessons for preventing future failures 

Mt. Rainier

August 2025

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

Managing the severe B2 glenoid in a 40 year old active man.

  A 40 year old very physically active man presented with pain, stiffness and feelings of instability of the right shoulder.  His axially "truth" view showed almost complete posterior decentering of the huneral on a retroverted biconcave glenoid. 

No additional imaging was deemed necessary.

The surgical options for this patient would seem to include (1) anatomic total shoulder without or with an augmented glenoid component, (2) reverse total shoulder, or (3) a ream and run procedure.

Because of his active lifestyle and young age, he wished to avoid the risks and limitations of a glenoid component and selected the ream and run option. After non-corrective glenoid reaming, an impaction-grafted smooth stem with an anteriorly eccentric humeral head was used to re-center the humeral head on the reamed glenoid,

He came back to the office fourteen years after his ream and run procedure reporting full function of this shoulder for all this athletic activities. His 14 year films (below) show centering of the anteriorly eccentric humeral head on the glenoid with no evidence of glenoid wear or erosion.

Now at the age of 54 he desires a ream and run for his progressively symptomatic left shoulder.

Since many patients are now using AI queries to answer health questions,  I asked ChatGPT, "what is the best treatment for a severe B2 glenoid in an active 40 year old man?" 

"I said:

what is the best treatment for a severe B2 glenoid in a 40 year old active man

ChatGPT said:

A severe B2 glenoid in a 40-year-old active man is one of the most challenging scenarios in shoulder arthroplasty. The goals in this patient are (1) durable correction of posterior subluxation, (2) preservation of bone stock, and (3) avoidance of early component loosening or the need for revision while maintaining activity tolerance.

Here’s how current thinking and evidence break down:

1. Joint Preservation vs. Arthroplasty

* Joint-preserving options (e.g., posterior bone grafting, biologic resurfacing, corrective osteotomy) have historically had poor mid- to long-term outcomes and high revision rates. They are rarely used in this age group today except in very select situations (e.g., low-demand, early arthritis).

* For a 40-year-old active patient, most surgeons will lean toward some form of anatomic arthroplasty if the rotator cuff is intact.

2. Anatomic TSA Options

A. Eccentric Reaming

* Indicated if posterior bone loss is <15° retroversion and correction can be achieved without excessive subchondral bone removal.

* In severe B2 (often >15–20° retroversion), eccentric reaming risks medialization, joint line shift, and instability.

B. Augmented Glenoid Components

* Posteriorly augmented polyethylene glenoid (e.g., stepped or wedge) corrects version without excessive reaming.

* Early/midterm studies: improved stability and function, lower risk of loosening compared with eccentric reaming.

* Limitation: long-term durability in young active patients remains under investigation.

C. Bone Grafting

* Posterior structural bone grafting with a standard glenoid component can restore version while preserving bone.

* Historically high risk of graft resorption and loosening, but newer techniques with rigid fixation have shown improved results.

* Best reserved for younger patients where bone preservation is paramount.

3. Reverse TSA

* Reverse is sometimes proposed in severe B2, especially in older patients or when cuff integrity is uncertain.

* In a 40-year-old active man with intact cuff, reverse is generally avoided because of concerns about implant longevity, scapular notching, and difficulty revising to another option later in life.

Sometimes the simplest solution is best

Female House Finch

Matsen Back Yard 

2022

Follow on twitter/X: https://x.com/RickMatsen
Follow on facebook: https://www.facebook.com/shoulder.arthritis
Follow on LinkedIn: https://www.linkedin.com/in/rick-matsen-88b1a8133/

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).

You said:

ChatGPT said: