How much precision do we need to pay for in shoulder arthroplasty?

In a recent series of posts, we've discussed the relationship of patient outcomes from shoulder arthroplasty to "component malposition" and to the use of costly technologies directed at precision in executing a preoperative plan (e.g. robotics, navigation, patient specific instrumentation). 

Does component malposition lead to revision of shoulder arthroplasty? points out that in order to understand the relationship of different degrees of malposition to outcome it is necessary to assess not only malpositions in failed arthroplasties but also malpositions in successful arthroplasties.

Humeral and glenoid component malposition in revised shoulder arthroplasty - Part I - what might have been done differently? recognizes that major component malpositions can cause failure, but questions whether precision technologies are necessary to avoid clinically significant malpositions.

Intraoperative navigation for shoulder arthroplasty - where are we going? suggests (1) The question each surgeon must ask is whether intraoperative navigation addresses problems experienced by patients in their own practice and (2)The question the field of shoulder surgery must ask is which specific patient problems (instability? fracture? stiffness? pain?) occur due to positioning errors that: (a) surgeons using standard techniques cannot adequately control, and (b) navigation systems would prevent. 

What should be the role of robotics in shoulder arthroplasty? asks "to what degree will the application of robotics to execute a preoperative plan address the primary causes of shoulder arthroplasty failure - infection, instability, acromial fracture, limited motion, and component loosening?"

 

Recognizing that the use of robotics, navigation and patient specific instrumentation all are based on a preoperative plan created from a 3D CT scan, CT-free planning for reverse total shoulder arthroplasty - why and how to do it shows a non-CT method for preoperative planning that is applicable to a large percentage of cases of reverse total shoulder arthroplasty cases.

Finally The Bad B2 Pandemic and How I perform a kinematic anatomic shoulder arthroplasty : what is the appropriate amount of stuffing? remind us that while image-based preoperative planning provides a useful preview to the surgery, the final choice of implants and positioning needs to be based on intraoperative assessment of soft tissue balance - something that preoperative images cannot reveal.

So, if precision means carrying out a preoperatively-generated plan, how much precision do we need to get the clinical outcome we want for our patient? 

For fun, let's consider a comparison of two watches:

(1) the world's most accurate watch

and (2) one of the world's cheapest watches

Here are some points of comparison

The F-91W $19.61 is less precise than the $7,400 Citizen Caliber 0100: ± 15 sec/month vs ± 1 sec/year (just as the conventional approach to the placement of shoulder arthroplasty components is less precise than technology-based placement). The question is whether the difference is of importance to the wearer (or the patient); does the 377 times increase in price produce a tangible benefit?

The Casio F-91W costs $19.61 on Amazon, where it is currently the #1 Best Seller in Men’s Wrist Watches — more than 3,000 sold in the past month, 57,798 customer reviews, 4.6 stars. It has a 7-year battery. It has been in continuous production since 1989. It has no Bluetooth, no Wi-Fi, no radio receiver, no GPS, and no wireless capability of any kind. There are four buttons on the case. That is the entirety of its interface with the outside world.

Its quartz oscillator drifts approximately fifteen seconds per month. Yet it gets its owner to every meeting, every appointment, every surgical case on time. The reason is straightforward: its imprecision is correctable: the wearer presses two of those four buttons while looking at an external time source. Similarly in the operating room we frequently adjust our preoperative shoulder arthroplasty component selection and positioning based on our intraoperative observations, rather than being fixed to our preoperative plan.

 

The Citizen Caliber 0100 costs seven thousand four hundred dollars. Its quartz oscillator vibrates at 8,388,608 Hz, temperature-compensated every sixty seconds. Its certified annual accuracy is ±1 second. It is, by the consensus of the watchmaking world, the most precise autonomous wristwatch ever produced. But it cannot be corrected because its extraordinary precision is entirely self-referential. It measures its own performance against its own internal standard, derived from its own crystal, monitored by its own circuitry. When that internal standard diverges from external reality — due to a subtle manufacturing variation, an unforeseen temperature excursion, a factor its algorithm did not anticipate — the watch has no mechanism to detect the divergence and no capacity to correct for it. There are no buttons to press. There is no external reference to consult. It proceeds with precision, faithfully, in whatever direction it was last pointed.

Technologies such as robotics, navigation and patient specific instrumentation face the same constraint. They strive to execute the preoperative plan with absolute fidelity. The plan was derived from a CT scan acquired days before surgery, segmented by an algorithm, calibrated to a population average, and fixed at the moment the case was planned. In the operating room, the technology cannot read the bone quality beneath the reamer. It cannot sense the soft tissue tension that requires adjustment. It cannot recognize that the patient’s anatomy, once exposed, differs in a clinically relevant way from the CT model it was given. It proceeds with precision, whether or not that precision is directed at the target that will yield the optimal outcome for the patient.

The F-91W, reset by a human being attending to ground truth, is the more honest model of what excellent surgery actually looks like: an imperfect instrument, actively corrected, continuously coupled to the reality it is meant to serve. There needs to be a human in the loop!

How much precision is needed?

Anna's Hummingbird

Matsen Backyard

 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). 

CT-free planning for reverse total shoulder arthroplasty - why and how to do it

The most recent Australian Orthopaedic Association's Joint Replacement Registry reveals that the use of CT scans prior to shoulder arthroplasty is increasing rapidly.

This use needs to be considered in light of five factors

(1)  Evidence is lacking that preoperative CT planning improves patient-reported outcomes, complication rates, or revision rates for common arthroplasty cases:

Use of Preoperative CT Scans and Patient-Specific Instrumentation May Not Improve Short-Term Adverse Events After Shoulder Arthroplasty: Results from a Large Integrated Health-Care System found "no reduction in the risk of aseptic revision was observed for patients having preoperative CT scans".

The influence of computed tomography preoperative planning on clinical outcomes after anatomic total shoulder arthroplasty: a matched cohort analysis found the differences in clinical outcomes between the CT and non-CT scan groups failed to meet a clinically significant threshold.

Templating in shoulder arthroplasty - A comparison of 2D CT to 3D CT planning software: A systematic review did not find evidence demonstrating differences in time, cost, functional outcomes, complications, or patient satisfaction.

3D CT-Based Preoperative Planning and Intraoperative Navigation in Reverse Shoulder Arthroplasty: Early Clinical Outcomes did not find statistically significant benefit of CT-based navigation with respect to complication rate, radiographical glenoid notching, and clinical outcomes

Assessing the Value to the Patient of New Technologies in Anatomic Total Shoulder Arthroplasty did not find evidence that the patient outcomes for shoulder arthroplasty were statistically or clinically improved with the use of advanced technologies, such as CT based planning.

(2) CT scanning and 3D planning increase the cost of healthcare by dint of their own costs. But they also initiate a "cost cascade" by driving the use of more expensive implants, and by driving the use of expensive "transfer technologies", such as patient specific instrumentation, virtual and augmented reality, and robotics. Because planning software packages are proprietary, they can drive the use of the implants associated the software, rather than the implants that may be more cost effective.

The influence of three-dimensional planning on decision-making in total shoulder arthroplasty. found 3-D planning influenced the choice of implant 

Impact of preoperative 3-dimensional planning and intraoperative navigation of shoulder arthroplasty on implant selection and operative time: a single surgeon's experience. found an almost three-fold increase in the use of the more expensive augmented components when using 3D preoperative planning 

Computer navigation re-creates planned glenoid placement and reduces correction variability in total shoulder arthroplasty: an in vivo case-control study. found that patients undergoing computer-assisted shoulder arthroplasty had more than twice as many augmented glenoid components as the conventional group 

However, none of these studies presented costs or clinical outcomes comparisons and thus it cannot be ascertained whether the use of augmented components was a cost-effective intervention or not.

Preoperative planning in reverse shoulder arthroplasty: plain radiographs vs. computed tomography scan vs. navigation vs. augmented reality concluded that further research is needed to determine the added value of these technologies in terms of improving clinical outcomes for the patients. The scarce evidence comparing short-term clinical outcomes of RSA with and without the use of these technologies show no or marginal benefits "Any benefit should be balanced against the increased costs and the 200 to 1,000-fold increase in radiation exposure associated with the CT scans in comparison with radiographs ".  

(3) Thus, In addition to its cost, CT scanning is associated with an increased lifetime risk of cancer

Computed Tomography for Preoperative Shoulder Arthroplasty Planning: Lifetime Malignancy Risk: The current reliance on preoperative shoulder CT for arthroplasty planning needs to be weighed against the potential lifetime cancer risks.

Projected Lifetime Cancer Risks From Current Computed Tomography Imaging found that at current utilization and radiation dose levels, CT examinations in 2023 were projected to result in approximately 103 000 future cancers over the course of the lifetime of exposed patients. If current practices persist, CT-associated cancer could eventually account for 5% of all new cancer diagnoses annually.

(4) Reverse shoulder arthroplasty (RSA) is a highly successful operation in the population-based study by the Australian Orthopaedic Association with 10 year revision rates under 6%. Note that these national data include all cases performed by all surgeons, not only "high volume" surgeons.

Complications and revision of reverse total shoulder arthroplasty found that 40% of revisions were for infection, 20% for instability/dislocation, 20% for loosening, and 10% for fracture. Evidence is lacking that CT scans, CT-based planning, and associated technologies have a substantial impact on these common reasons for RSA revision. 

Patient-Specific Instrumentation Versus a Free-Hand Technique for Glenoid Baseplate and Peripheral Screw Placement in Reverse Total Shoulder Arthroplasty Using the Exactech Implant System: A Multicenter Randomized Controlled Trial concluded "in primary rTSA, PSI did not improve glenoid baseplate positioning compared to a free-hand technique"

(5) In most cases, cost-effective preoperative planning can be efficiently carried out without a CT scan. 

Here's a way to it in under ten minutes using the Picture Archiving and Communication Systems (PACS) tools applied to two standardized preoperative plain films (AP view in the plane of the scapula and axillary view). This approach is generic and is not tied to any commercial company, allowing surgeons to have their choice of implant. It can be used by essentially all shoulder surgeons. It provides an approach for transferring the plan to the patient. It is cost-effective - an important feature, especially at this time when many are having difficulty affording health care.

Step 1, on the AP view, draw a line along the base of the supraspinatus fossa (yellow line in right hand image).

Step 2, draw a line segment  equal to the radius of the base of the glenosphere from the inferior glenoid at a right angle to the supraspinatus fossa line so that it intersects the glenoid face (yellow line on left image below). This intersection will be the starting point for the drill for the central scew of the baseplate. This point will be located at surgery by measuring the distance from this point to the inferior lip of the glenoid (yellow line on right image below). Note that the amount of bone that will be removed by reaming is represented by the triangle in between these two lines.

Step 3 Draw a line parallel to the supraspinatus fossa line that intersects the glenoid face at the insertion point (yellow line on left image); this is the trajectory of the drill. Measure the angle between this line and the face of the upper glenoid (yellow line on right image) to guide the tilt of the drill at surgery.

Step 4 On the axillary view, draw the desired trajectory of the central screw so that it will just penetrate the anterior cortex of the subscapularis fossa when fully inserted (central image). Note the angle of this line with the gleniod face (right image) to guide version of drill at surgery.

The resuling arthroplasty closely approximates the plan.

Another example

And another

CT-free planning is consisted with the philosophy expressed in the preface of Practical Evaluation and Management of the Shoulder (1994): "This book is directed at the type of practice we see evolving for the coming decades, when resources will not be as plentiful and increasing premiums will be placed on economy and effectiveness. In this spirit, we emphasize what can be accomplished with the basics: the clinical history, the physical examination, a few plain radiographs, simple patient-conducted rehabilitation programs, and well-characterized surgical procedures. "

Thanks to our two shoulder fellows, Jake Checketts and Dave Daniels, for their help with this post. They easily mastered this method and routinely apply it to all but the unusual cases of reverse shoulder arthroplasty (i.e. those with severe bone loss, complex revision cases, significant deformity).

Making a Plan

Osprey 

Union Bay Natural Area

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).

Glenoid version: acceptors and correctors

At a recent Cantina luncheon, conversation among five shoulder surgeons concluded that shoulder surgeons are becoming divided with respect to their approaches to arthritic shoulders with glenoid retroversion: there are the "acceptors" and  the "correctors".

The acceptors ream the glenoid only enough to create a smooth concavity that corresponds to the backside of the glenoid component. The correctors strive to reduce glenoid retroversion to 15 degrees or less, using posteriorly augmented glenoid components, anterior "high side" reaming, or posterior bone graft. 

The acceptor approach requires only standardized plain radiographs and the occasional use of anteriorly eccentric humeral head components and rotator interval plication if excessive posterior decentering is noted at surgery. 

By contrast, the corrector approach usually requires a preoperative CT scan, three dimensional planning, and some means of carrying out the plan in the operating room, such as patient specific instrumentation or computer guidance.

The literature available to date does not demonstrate a superiority of either approach in terms of clinical outcomes in the management of arthritic shoulders with a retroverted glenoid.

It is of interest to see how the corrector and acceptor approaches are used in a membership-based, dues prepaid, direct health care system, where optimization of both outcome as well as total outpatient and inpatient costs are priorities. The authors of Use of Preoperative CT Scans and Patient-Specific Instrumentation May Not Improve Short-Term Adverse Events After Shoulder Arthroplasty showed how the corrector-oriented technologies - preoperative computed tomography (CT) scans and patient-specific instrumentation (PSI) - are used in their integrated health-care system.

They identified 8,117 primary elective anatomic or reverse total shoulder arthroplasties (7,372 patients) performed by 130 surgeons between 2015 to 2020 with an average follow-up of 2.9 years (maximum, 6 years).  

During the period of this observational study, the 130 surgeons in this healthcare system chose to use preoperative CT scans in less than half of the primary shoulder arthroplasties and to use PSI in one out of nine cases. 

CT Scans

The use of preoperative CT scans is probably associated with the surgeons' desire to correct preoperative glenoid version.

Over the period of this study it appears that the surgeons became more selective in their use of preoperative CT scans:

(1) less than half of all shoulder arthroplasty patients had preoperative CT scans; this percentage trended downward with time

(2) patients with glenoid types B1 and B2 were slightly more likely to get preoperative CT scans, whereas patients with A1 glenoids were slightly less likely to have CT scans; yet for each glenoid type, less than one third of patients had preoperative CT scans

The arthroplasty surgery of patients having CT scans took 12% longer and had somewhat higher cumulative revision rates

and had a higher likelihood of venous thromboembolism (OR = 1.79; 95% CI = 1.18 to 2.74) compared with those without CT scans.

Patient Specific Instrumentation

The use of PSI is probably associated with the surgeons' desire to correct preoperative glenoid version.

3553 (44%) of the patients received a Tornier implant; of these 400 (11.3%) had their implants inserted using patient specific instrumentation. Shoulders with PSI were more likely to be male and to have a Walch type B or C preoperative glenoid pathoanatomy. Surgical procedures using PSI also had a longer mean operative time. 

The patients receiving arthroplasty with PSI had slightly increased rates of early revision.

Patients with PSI use had a higher likelihood of 90-day deep infection (OR = 7.74; 95% CI = 1.11 to 53.94), which may be related to the increased OR time.

 

Comment: At this point it is not clear how much "correction" of version is necessary to obtain a great outcome for the patient.

In Does Postoperative Glenoid Retroversion Affect the 2-Year Clinical and Radiographic Outcomes for Total Shoulder Arthroplasty? the authors presented a series of anatomic total shoulders in which neither 3D imaging or PSI was used; postoperative glenoid retroversion was not associated with inferior clinical results at 2 years after surgery.

Glenoid retroversion does not impact clinical outcomes or implant survivorship after total shoulder arthroplasty with minimal, noncorrective reaming found reliable increases in patient satisfaction and clinical outcomes in patients with up to 40 degrees of retroversion.

Baseplate retroversion does not affect postoperative outcomes after reverse shoulder arthroplasty. found no significant difference in postoperative functional outcomes, range of motion, or complications between patients who had baseplate retroversion ≤15° vs. those who had retroversion >15°.

Many of the published articles discussing CT planning, PSI and computer guidance focus on the accuracy and precision achieved with the techniques rather than clinical outcomes; see 

Accuracy of 3-Dimensional Planning, Implant Templating, and Patient-Specific Instrumentation in Anatomic Total Shoulder Arthroplasty. 

Version and inclination obtained with 3-dimensional planning intotal shoulder arthroplasty: do different programs produce the same results?

The influence of three-dimensional planning on decision-making in total shoulder arthroplasty.

Patient-specific Guides Using 3-dimensional Reconstruction Provide Accuracy and Reproducibility in Reverse Total Shoulder Arthroplasty.

Patient-specific instrumentation for total shoulder arthroplasty: not as accurate as it would seem.

Accuracy of patient-specific instrumentation in shoulder arthroplasty: a systematic review and meta-analysis.

Commercial 3-dimensional imaging programs are not created equal: version and inclination measurement positions vary among preoperative planning software.

Strategies to assist in the correction of glenoid pathoanatomy have not been associated with clinically significantly improved patient outcomes.

For example, the authors of The influence of computed tomography preoperative planning on clinical outcomes after anatomic total shoulder arthroplasty: a matched cohort analysis. did not find a clinically significant difference between the outcomes of total shoulders performed without and with 3D CT planning. 

In Patient-specific Instrumentation Versus Standard Surgical Instruments in Primary Reverse Total Shoulder Arthroplasty: A Retrospective Comparative Clinical Study, patient having RTSA with PSI did not achieve significantly different clinical outcomes than those without PSI. 

The authors of Early clinical outcomes following navigation-assisted baseplate fixation in reverse total shoulder arthroplasty: a matched cohort study found that navigated and non-navigated RSAs yielded similar rates of improvement in range of motion and functional outcome scores.

Assessing the Value to the Patient of New Technologies in Anatomic Total Shoulder Arthroplasty. found that since the advent of preoperative computed tomography (CT) scans, 3-dimensional preoperative planning, and patient-specific instrumentation there is a lack published evidence that the results of TSA have been statistically or clinically improved.

In conclusion, more research is needed to determine the clinical outcomes for the corrector and acceptor approaches to shoulders with different degrees of glenoid retroversion.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

Follow on twitter: https://twitter.com/shoulderarth
Follow on facebook: click on this link
Follow on facebook: https://www.facebook.com/frederick.matsen
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).

Shoulder Arthroplasty Planning Technologies

Innovations in shoulder arthroplasty seek to improve clinical outcomes for patients, Three-dimensional computer tomographic (CT) scans provide a more detailed depiction of glenoid pathoanatomy than traditional two-dimensional CT scans or plain films. Preoperative planning software enables the surgeon to visualize different reconstruction strategies. Patient specific instrumentation and computer assisted navigation strive to optimize implant positioning.  These technologies can add time and cost to the conduct of shoulder arthroplasty (data on average selling price (ASP) below from Orthopaedic Network News 2023). 

Certain questions about these technologies need to be answered by clinical research:

(1) Do these technologies improve the outcomes for patients in terms of improvement in comfort and function along with a reduction in complications and revisions?
(2) If these technologies are of value, in which cases should they be used - what are the "appropriate use criteria" for them?
(3) Are there potential adverse effects associated with the use of the technologies, such as increased rates of infection from prolonged operative time?
(4) Do these planning systems lead to the use of more complex implants (e.g. augmented baseplates for reverses and augmented poly for anatomic glenoid components) that may not be necessary.
(5) Do the different planning technologies results in similar measures, for example of glenoid inclination and version?

(6) How do the results reported by authors with financial conflicts of interest compare to those reported by authors without such conflicts?

Some recent articles bear on these questions:

In 3D preoperative planning for shoulder arthroplasty: an evaluation of different planning software systems it was found that the wide variety of methods used by different companies and institutions results in significantly differing glenoid inclination and version measurements.

In Does commercially available shoulder arthroplasty preoperative planning software agree with surgeon measurements of version, inclination, and subluxation? Preoperative planning software for shoulder arthroplasty had limited agreement in measures of version, inclination, and subluxation measurements.

In The Impact of Preoperative Three- Dimensional Planning and Intraoperative Navigation of Shoulder Arthroplasty on Implant Selection and Operative Time. Using 3D planning increased the likelihood that the surgeon selected an augmented glenoid component compared with 2D planning. Because 3D planning and intraoperative navigation is more costly than 2D planning, and augmented glenoid components are more costly than standard glenoid components, the cost-benefit of these changes with respect to mid- and long-term clinical outcomes and implant survival has not been ascertained.

In Patient-specific Instrumentation Versus Standard Surgical Instruments in Primary Reverse Total Shoulder Arthroplasty: A Retrospective Comparative Clinical Study patients having reverse total shoulder arthroplasty using patient specific instrumentation did not achieve significantly better clinical or radiographic outcomes than those performed without PSI.

As would be expected, authors advocating these technologies are often involved with their development and have financial ties to the companies providing them.Financial support is necessary for the research, development, application, and advocacy of new technologies. In Novel Shoulder Arthroplasty Planning Technologies and Potential Conflicts of Interest most publications on these innovations were found to be authored by those with financial conflicts of interest. Such conflicts can be associated with the results of the studies (Conflict of interest in orthopaedic research. An association between findings and funding in scientific presentations)(Conflict of interest in orthopaedic research)(Demographics of disclosure of conflicts of interest at the 2011 annual meeting of the American Academy of Orthopaedic Surgeons)(Scope and impact of financial conflicts of interest in biomedical research: a systematic review).

Clinical research, including carefully controlled clinical trials, are needed to establish the value of these technologies to the patient having arthroplasty for glenohumeral arthritis.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

Follow on twitter: https://twitter.com/shoulderarth
Follow on facebook: click on this link
Follow on facebook: https://www.facebook.com/frederick.matsen
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).

Is Blueprint 3D planning of value in predicting the postoperative range of motion after reverse total shoulder arthroplasty?

Surgeons use 3D planning software to better understand the shoulder's pathoanatomy and to optimize the fixation of arthroplasty components. There is also the anticipation that this approach to planning can help optimize the function of the arthroplasty.

The authors of a recent article, Assessment of 3D automated software to predict postoperative impingement free range of motion after reverse total shoulder arthroplasty, found that "In its current state, preoperative Blueprint 3D CT planning software is unable to accurately predict range of motion one year after reverse total shoulder arthroplasty". The authors of Templating in shoulder arthroplasty - A comparison of 2D CT to 3D CT planning software: A systematic review concluded that, "The paucity of evidence exploring clinical parameters makes it difficult to comment on clinical outcomes using different methods of templating. More studies are required to identify how improved radiographic outcomes translate into improvements that are clinically meaningful to patients."

To further assess the value of 3D planning in optimizing shoulder function after a reverse total shoulder, the author of Accuracy of Blueprint in Predicting Range of Motion One Year After Reverse Total Shoulder Arthroplasty sought to test the hypothesis that the mean impingement-free range of motion predicted by Blueprint correlates with the mean actual range of motion one year after reverse total shoulder arthroplasty in 127 shoulders. Interestingly, the surgeon elected to deviate from the Blueprint plan in 30 cases (almost 25%), making intraoperative component modifications.

He found that the actual range of motion and predicted range of motion were statistically significantly different (p<0.0001) for flexion, external rotation, abduction, abduction/ external rotation, and abduction / internal rotation.


As seen below, some predictions were less than what was seen at 1 year (e.g. flexion and abduction). However, actual range of motion was substantially less that predicted for other motions (e.g. abduction/internal rotation). Of note, one of the concerns with reverse total shoulder arthroplasty is the frequent limitation of the ability to regain sufficient internal rotation enabling reach up the back.

The conclusion was that "In its current state, preoperative Blueprint 3D CT planning software is unable to accurately predict range of motion one year after reverse total shoulder arthroplasty."

Comment: Without or with preoperative planning software, the surgeon has the opportunity to evaluate the ranges of motion with different combinations of trial components - seeking to avoid unwanted contact between the humeral component and the scapula inferiorly, anteriorly and posteriorly

as well as taking steps to avoid unwanted contact between the greater tuberosity and the undersurface of the acromion. 

We can try it before we buy it.

You can support cutting edge shoulder research that is leading to better care for patients with shoulder problems, click on this link.

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

Follow on facebook: click on this link

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

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).