Sunday, February 1, 2026

The Bad B2 Pandemic Continues - by now, you can guess the treatment we selected.

Here's a case from last week: 40 year old very active man with these x-rays 




From the white board in the OR, ROM under general anesthesia

Thus we have the familiar B2 paradox: a posteriorly decentered, unstable shoulder that is also stiff (FE -forward elevagion; ER - external rotation at the side; ERA - external rotation in abduction; IRA - internal rotation in abduction; CBA - cross body adduction (distance from antecubital fossa of surgical arm to contralateral acromion in cm)).

From the responses to the Jan 29 post, many surgeons would consider a reverse total shoulder, or an anatomic total shoulder with a posterior augment.

Our preop preview suggested a 50 20 humeral head. A preoperative CT was not obtained.



As usual the procedure was performed under a general anesthesia without nerve block. The shoulder was approached through a subscapularis peel, preserving the long head tendon of the biceps.

At surgery, the glenoid was biconcave in the posterior inferior direction (ellipse) rather than directly posterior with respect to superior / inferior axis (yellow line). This pathoanatomy would have been difficult to fit using an augmented glenoid component without excessive bone removal.


The glenoid was conservatively reamed to a monoconcavity without attempting to change glenoid version.





A short humeral stem was inserted.
As pointed out in prior posts, the key is not a preoperative plan or attempting to match a preoperative plan with expensive technology (e.g. robotics, patient specific instruments, virtual reality, or augmented reality). These approaches do not recognize the importance of soft tissue balancing. 
Instead, we use intraoperative decision-making after osteophyte resection and appropriate tissue releases that recognize the soft tissues' and the implants' combined contributions to the shoulder's mobility and stability.

Trialing with the standard 50 20 head revealed excessive soft tissue tightness on the 150, 40, 50, 60 tests. Trialing with the strandard 50 18 head revealed excessive posterior translation.

Trialing with the anterioly eccentric 50 18 head revealed excellent balance of stability and mobility (160 FF, ER 20, IRA 60, 50% posterior translation). 

His postoperartive range of flexion is shown here


His recovery room films are shown here


For comparison, here's his preoperative axillary 'truth' view (note the standardization of the projection and arm position)


We will start assisted flexion at 2 weeks post op.

See also the case at the top of this page under the W

It's all about balance


Black-necked Stilt

Malheur National Wildlife Refuge

Spring 2025



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). 










Posted by at
Labels: , , , ,

Thursday, January 29, 2026

The Bad B2 in active patients - the ream and run using the anteriorly eccentric humeral head to recenter the joint.

The Bad B2 glenoid is frequently encountered in our arthroplasty practice. In a previous post I presented the two cases of quality of life limiting Bad B2 pathoanatomy below for thoughts on management. Options included reverse total shoulder, anatomic total shoulder without or with augmented glenoids or bone grafting, and various types of hemiarthroplasty. 

Each patient was treated with the classic ream and run using an anteriorly eccentric humeral head to re-center the posteriorly unstable articulation. No preoperative CT scan or 3D planning were used in either case. The procedures were performed under general anesthesia without a plexus block. The long head tendon of the biceps was preserved in both cases. The subscapularis was peeled and repaired with six fiberwire sutures and a mild rotator interval closure.

Coincidentally, both patients returned for their two-year followups on the same day. Both reported the ability to perform each of the 12 functions of the Simple Shoulder Test. Both had strong subscapularis function.


51 year old active man






64 year old active man





Cutting to the chase


Scissor-tailed Flycatcher

Austin, Texas
 2025


Posted by at
Labels: , , ,

Tuesday, January 27, 2026

The Bad B2 - a challenge. What would you do?

The Bad B2 glenoid is frequently encountered in our arthroplasty practice. How would you manage each of these two cases? Respond on LinkedIn.


51 year old active man


64 year old active man



Posted by at
Labels: ,

Monday, January 26, 2026

Reverse total shoulder - hear the experts from ASES

ASES will provide a Virtual Journal Club on Reverse Total Shoulder, Tuesday, January 27th at 7pm CST, featuring moderators Drs. Christopher Klifto and Eric Wagner and panelists: Drs. Emilie Cheung, Larry Gulotta and Joaquin Sanchez-Sotelo (click on this link).

Here are some recent posts regarding the articles to be featured in the journal club

American Shoulder and Elbow Surgeons Journal Club on Reverse Total Shoulder Arthroplasty - a reflections on the articles. Part 1

Conjoint Tendon Release in Reverse Total Shoulder Arthroplasty. American Shoulder and Elbow Surgeons Journal Club on Reverse Total Shoulder Arthroplasty - a reflections on the articles. Part 2

Humeral component retroversion in RSA American Shoulder and Elbow Surgeons Journal Club on Reverse Total Shoulder Arthroplasty - a reflections on the articles. Part 3





Posted by at
Labels: , ,

Friday, January 23, 2026

Humeral component retroversion in RSA American Shoulder and Elbow Surgeons Journal Club on Reverse Total Shoulder Arthroplasty - a reflections on the articles. Part 3

One of the less frequently studied surgeon-controlled variables in reverse total shoulder arthroplasty is the version of the humeral component. Humeral component retroversion in the Comprehensive Reverse Shoulder System arthroplasty: rotations, clinical outcomes, and quality-of-life analysis in a prospective randomized study: 60 patients were randomized; 57 analyzed at 24 months, mean age 75, 85% female, massive rotator cuff tear (63.3%), rotator cuff arthropathy (23.3%), primary osteoarthritis (13.3%) having RSA with Comprehensive Reverse Shoulder System by an individual surgeon. 

30° retroversion improved external rotation at 0° abduction by 12° but compromised functional outcomes as revealed by the Simple Shoulder Test (SST) and quality of life (SF-12 PCS) compared to 0° retroversion. Functional internal rotation showed only marginal improvement with 0° retroversion (approximately one spinal level).

The 0° group achieved clinically significantly higher SST scores, and superior quality of life in the physical domain, despite reduced external rotation with the arm at the side.

No significant differences were detected in ASES or Constant-Murley scores. These instruments may be less sensitive than the SST to the specific functional trade-offs between rotation patterns. The SST asks practical questions: Can you sleep comfortably? Carry 10 pounds? Wash the opposite shoulder? These activities may benefit from the subtle balance achieved at 0° retroversion with this implant.

It is worthy of note that the Comprehensive Reverse Shoulder System is a highly lateralized design. Thesse results may not apply to medialized designs, different glenosphere sizes, or varying humeral shaft angles. The interaction between retroversion and lateralization remains unexplored.

Conclusion: With Comprehensive Reverse Shoulder System laateralized design implant:

1. 30° retroversion increases ER at the side by 12° (clinically significant) but does not improve ER in abduction or functional ER scoring.

2. 0° retroversion provides only marginal internal rotation improvement that falls short of clinical significance and challenges computational model predictions.

3. The Simple Shoulder Test and SF-12, by assessing actual task performance and perceived quality of life, provide insight into what patients actually experience—which may differ substantially from what surgeons measure.

4. 0° retroversion achieves superior Simple Shoulder Test scores and physical quality of life despite less ER at the side, suggesting better integration of motion patterns for activities of daily living.

It not known if  these findings apply to medialized systems, different glenosphere sizes, or varying humeral shaft angles. Each implant design may have an optimal version range requiring separate study.

The study also highlights the importance of patient-reported outcomes in arthroplasty research. Goniometric measurements of range of motion, while objective and quantifiable, capture only one dimension of shoulder function. The Simple Shoulder Test and SF-12, by assessing actual task performance and perceived quality of life, provide insight into what patients actually experience—which may differ substantially from what surgeons measure.

Finally, this work reminds us that surgical decision-making remains complex and incompletely understood. The interaction of multiple variables—implant design, soft tissue management, bone morphology, patient factors—creates a multivariate problem that defies simple solutions.

Progress requires well-designed studies like this one, asking focused questions with rigorous methodology, gradually building the evidence base that will guide future practice.


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). 


Posted by at
Labels: , ,

Conjoint Tendon Release in Reverse Total Shoulder Arthroplasty. American Shoulder and Elbow Surgeons Journal Club on Reverse Total Shoulder Arthroplasty - a reflections on the articles. Part 2

Background: Internal rotation limitation is prevalent following modern reverse shoulder arthroplasty and negatively affects patients' subjective rating of the procedure. Internal rotation limitation after reverse total shoulder is common (41% of patients can only reach to sacrum level or worse) and negatively affects patient satisfaction. IR limitation is an independent factor associated with lower patient rating after RSA. Most research has been focused on implant geometry (lateralization, glenosphere position/size, NSA, version) with limited success.

Extension of the shoulder is essential for functional internal rotation after reverse total shoulder arthroplasty


The Journal Club Article:

Conjoint tendon release results in improvedinternal rotation and pain following reverse shoulder arthroplasty: a combined randomized clinical trial and biomechanical study included a level I RCT (55 patients) plus biomechanical validation (6 cadaveric specimens) study of  Z-plasty release of conjoint tendon 2 cm distal to coracoid.

In the clinical study, the released shoulders showed a modest improvement in reach up the back and lessening in pain, but these differences were not clinically significant (MCID for pain score = 1.5). There was no difference in the ASES score between the groups.


The postoperative internal rotation was greater for shoulders with greater preoperative internal rotation.

In the cadaveric study, the increases in internal rotation and extension were statistically significant but less than 10°. The force to subluxate was decreased by 4.3 N.

Conclusion: While internal rotation deficits are common and problematic after RSA, in this study the improvements in internal rotation after conjoint tendon release were modest and did not provide clinically significant improvement for the patients. 

It has been previously noted that function-specific patient reported outcomes, such as the Simple Shoulder Test, are more sensitive than global PROs in detecting internal rotation deficits after reverse total shoulder arthroplasty. It has also been documented that the ability to reach up the back (not a strictly rotational measure) is heavily influenced by the range of shoulder extension.



See:

Functional internal rotation after shoulder arthroplasty: a comparison of anatomic and reverse shoulder arthroplasty

In comparison to anatomic total shoulder, reverse total shoulder is associated with greater anterior shoulder pain and internal rotation dysfunction in patients with osteoarthritis.

Factors influencing functional internal rotation after reverse total shoulder arthroplasty


Takeaway: conjoint tendon release may be considered when performing RSA if extension is limited




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). 
Posted by at
Labels: , , , ,

Thursday, January 22, 2026

American Shoulder and Elbow Surgeons Journal Club on Reverse Total Shoulder Arthroplasty - a reflections on the articles. Part 1

ASES will provide a Virtual Journal Club on Reverse Total Shoulder, Tuesday, January 27th at 7pm CST, featuring moderators Drs. Christopher Klifto and Eric Wagner and panelists: Drs. Emilie Cheung, Larry Gulotta and Joaquin Sanchez-Sotelo (click on this link).

Here are some thoughts on two of the articles to be discussed.

(1) Scapulothoracic orientation has a significant influence on the clinical outcome after reverse total shoulder arthroplasty reported a retrospective analysis of 681 primary rTSA patients from a single-center registry. Patients were classified into three posture types based on scapular internal rotation measured on preoperative cross-sectional imaging:

• Type A: ≤36° scapular internal rotation (n=225)
• Type B: >36° to 46° (n=326)
• Type C: >46° (n=130) - represents poorest posture with increased kyphosis. At two years after surgery these patients had a few degrees (6 to 10 degrees) worse range of motion than type A. While the SPADI scores were 9 points worse, the difference did not exceed the MCID. Similarly the pain scores and complication rates were not clinically significantly different between types A and C.

The study is limited by (1) the  fact that posture was measured in a static supine position not during function while standing and confounded because (2) the types differed with respect to patient sex (more females in type C) and type of implants (more Grammont types used in type C).  While it is speculated that type C patients would benefit from increased distalization and potentially more lateralized constructs, this was not demonstrated in this paper.


(2) The relationship between design-based lateralization, humeral bearing design, polyethylene angle, and patient-related factors on surgical complications after reverse shoulder arthroplasty: a machine learning analysis considered 3,837 primary rTSA procedures using machine learning to predict surgical complications. Complications occurred in one out of eight patients, with superficial infections (2.1%), acromial/scapular fractures (2%), and instability (1.6%) being most common.

Patient factors (younger age, tobacco use, prior surgery, diagnosis of instability sequelae or nonunion) were stronger predictors of complications than implant design (inlay humeral component, medialized glenoid, medialized humerus, minimal global lateralization, lateralized glenoid-medialized humerus).

The machine learning model achieved an AUC-ROC of 0.61 (the value for random change would be 0.5).




This study reinforces that patient selection and optimization are paramount, with surgical technique and implant design playing less important roles. The findings appear to favor lateralized constructs (glenoid and humeral components) and onlay designs. However, the modest predictive accuracy suggests complications are multifactorial and not easily predicted.

The authors carefully describe the limitations of the study:
(1) the study retrospectively analyzed patients from an institutional registry
(2) glenoid, humeral, and global lateralization were measured on digitized templates as opposed to radiographic measures (thus, surgeon technique may have had a major impact on the final implant position different than the manufacturer specifications).
(3) the case volume of the individual surgeons was not analyzed with respect to complication rate.
(4) the medialized designs were the only implants available during the learning period of rTSA at this institution; thus it is unclear whether the increased complications associated with this design were related to the design itself or due to surgeon inexperience. In this registry, lateralized constructs were associated with fewer complications, but this may reflect their use in later years by more experienced surgeons in better-selected patients.
(5) the implants with lower proportions in the study led to more statistical fragility regarding design parameters
(6) it is not clear whether complications with certain designs (for example, the lateralized glenoid-medialized humerus (LGMH) combination) were due to the implant or to differences in the patient populations receiving the different implants
(7) the modest AUC-ROC of 0.61 suggests that the model did not include additional important predictive factors (e.g. surgical technique, other patient factors).
(8) this study looks at associations, but we cannot determine whether the associations imply causation  (i.e. does the use of certain implants cause an increased risk of complications?). See Surgical failures: what causes them and how can we do better for our patients.

We might wonder if in the future natural language processing of the entire records of these patients might lead to a model with greater predictive capacity by capturing such potentially important variables as:
  • Intraoperative findings (bone quality, soft tissue (subscapularis) condition, unexpected anatomic variants)
  • Surgeon operative notes describing technical challenges
  • Rehabilitation compliance and early recovery patterns
  • Social determinants of health (support systems, living situation)
  • Detailed medication histories and comorbidity severity
  • Patient expectations and psychological factors

In the end we must ask: Are complications in rTSA fundamentally predictable, or are there elements (e.g., subclinical infections, individual healing variability, unpredictable trauma) that limit any model's ceiling? 

Is the modest AUC of 0.61 due to insufficient data or to irreducible uncertainty (inherent biological variability among patients, intraoperative details, postoperative course)? 

See Objective ignorance - a problem in predicting outcomes in climbing and in orthopaedic surgery

Here's how a conversation with a prospective patient about complications might go.

What we know: "Your age, tobacco use, overall health, nutrition and whether you've had prior surgery influence your risk of complications. We can't change some of these, but we can optimize your nutrition and help with smoking cessation if relevant. At your surgery, we'll use proven techniques and appropriate implants based on the best available evidence."

What we don't know: "Even with sophisticated analysis of thousands of cases, we can only weakly predict who will experience a complication. Much depends on factors we cannot measure or control—how your body responds to surgery, healing variability, and events after you leave the hospital."

What this means for you: "We focus our efforts where evidence shows they matter most: optimizing your health before surgery, using proven surgical approaches, and supporting your recovery afterward. We avoid expensive technologies that claim precision but haven't been shown to improve outcomes that matter to patients."



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). 







Posted by at
Labels: , ,
Subscribe to: Comments (Atom)