Thursday, May 21, 2015

Posterior glenoid wear, glenoid retroversion and the BAT: evaluation and management

One of the hottest topics in shoulder surgery is the evaluation and management of the retroverted glenoid - a most common pathology in shoulder arthritis.  Here are our answers to some commonly posed questions

1. How do you assess pre-operative retroversion and glenoid wear in OA?

Eccentric posterior glenoid wear, glenoid retroversion, and posterior humeral subluxation constitute the ‘bad arthritic triad’ (BAT). The BAT is quite common in osteoarthritis and in capsulorrhaphy arthropathy. For the past four decades we have relied only upon standardized anteroposterior and axillary x-rays to define on the pre-arthroplasty glenohumeral anatomy. Our x-ray technologists have no difficulty in routinely obtaining (1) an anteroposterior view in the plane of the scapula and (2) an axillary view taken with the arm in the functional position of elevation in the plane of the scapula that shows the spinoglenoid notch and the body of the scapula. The three figures below demonstrate the use of the standardized axillary view to document functional decentering of the humeral head on a posteriorly eroded glenoid (left), the degree of glenoid retroversion (middle) and the posterior displacement of the point of glenohumeral contact (right)


In our practice routine CT scans are avoided because of their cost, their radiation dosage, the impracticality of using them for postoperative follow-up and the inability of CT scans taken with the arm at the side to detect the functional decentering of the humeral head that occurs when the arm is elevated.

2. What degree of retroversion or glenoid wear do you depart from standard procedures?

Except in cases of true glenoid dysplasia, we have not found it necessary to depart from our standard approach to arthroplasty. In treating glenoid retroversion, we do not use (a) reaming of the high side, (b) glenoid bone grafts, (c) posteriorly augmented glenoid components, or (d) patient specific instrumentation in that these are not necessary to achieve stability of the reconstruction. A reverse total shoulder is used only in the rare cases of extreme posterior instability that cannot otherwise be managed.

Our approach – whether for a ream and run procedure or for a total shoulder - is to conservatively ream the glenoid to a single concavity without trying to ‘normalize’ version. As a result, the amount of glenoid bone removed by reaming is very small. The humeral head is balanced on the glenoid by using a humeral head width that offers 50% posterior translation of the head and 60 degrees of internal rotation with the arm in 90 degrees of abduction. If necessary to achieve posterior stability, we use an anteriorly eccentric humeral head component and/or a rotator interval plication.

3. What is the optimal situation for ream and run?

Glenohumeral osteoarthritis involves, by definition, both the glenoid and the humeral sides of the joint. For the average patient, we recommend a total shoulder arthroplasty as the procedure most likely to provide improvement in comfort and the ability to perform the basic activities of daily living. We discuss the ream and run with exceptionally motivated patients with OA who desire a high level of function (throwing; boxing, karate, chopping wood, weight lifting, football, hockey) and for those who wish to avoid the risks of failure of a plastic glenoid component.

4. When you would steer clear of a ream and run?

In patients with inflammatory arthritis, smokers, narcotic pain medication, depression, or lack of convincing motivation

5. What age range do you consider a ream and run?

18 to 80 years of age

6. How much glenoid retroversion can be managed with a ream and run?

We have had success with the ream and run on glenoids with as much as 40 degrees of retroversion

7. Can you show a case that illustrates the management of the bad arthritic triad with a ream and run?

The images below are the anteroposterior and standardized axillary views of a 50 year old man with the BAT of his left dominant shoulder after a prior anterior instability repair years previously.

Shown below are the corresponding views one year after a ream and run with an anteriorly eccentric humeral head but without ‘normalization’ of his glenoid version.

At one year after his ream and run he had returned to weight lifting, tennis, baseball pitching, basketball, pull-ups, hand stand push ups, and football passing as shown in this link.

Now five years after surgery he retains the comfort and function of his ream and run shoulder.

Be sure to click on this link to the Shoulder Arthritis Book.

Consultation for those who live a distance away from Seattle.

Click here to see the new Shoulder Arthritis Book

Click here to see the new Rotator Cuff Book

To see the topics covered in this Blog, click here

Use the "Search" box to the right to find other topics of interest to you.

You may be interested in some of our most visited web pages including:shoulder arthritis, total shoulder, ream and runreverse total shoulderCTA arthroplasty, and rotator cuff surgery as well as the 'ream and run essentials'