Panel discusses preoperative assessment and role for hemiarthroplasty, RSA for patients with glenoid wear

The management of patients with glenohumeral osteoarthritis and glenoid wear is difficult. Conservative treatment risks more glenoid wear, further compromising our reconstructive options. Reverse shoulder arthroplasty has potentially added a new tool for age appropriate patients. But at what age? Many patients with osteoarthritis and glenoid wear are young and active. A variety of treatment options have been proposed and have their proponents, whereas others embrace older methods with refined indications and techniques. Others explore the utility of new technologies, such as patient-specific instrumentation, augmented glenoid components and reverse shoulder arthroplasty.

In this Orthopedics Today Round Table discussion, I asked some of the most experienced and thoughtful surgeons in the field a few questions to gain insight into their approach to this challenging patient population.

Michael Pearl, MD
Moderator

Michael Pearl, MD: How do you assess preoperative retroversion and glenoid wear for your shoulder arthroplasty cases? Do you eyeball it and classify or use analytical software and measure? Does everyone get CT scans with 3-D reconstructions? Do you use patient-specific instrumentation (PSI)?

Frederick A. Matsen III, MD: Eccentric posterior glenoid wear, glenoid retroversion and posterior humeral subluxation constitute the “bad arthritic triad” (BAT). The BAT is common in osteoarthritis (OA) and in capsulorrhaphy arthropathy.

For the past 4 decades, we have relied only upon standardized anteroposterior and axillary radiographs to define the prearthroplasty glenohumeral anatomy. Our X-ray technologists have no difficulty in routinely obtaining the AP view in the plane of the scapula and 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 (Figures 1 and 2).

Image: Matsen FA III

Image: Matsen FA III

Figure 1 also demonstrates the use of the standardized axillary view to document functional decentering of the humeral head on a posteriorly eroded glenoid, the degree of glenoid retroversion and the posterior displacement of the point of glenohumeral contact. In our practice, CT scans are avoided because of their cost, radiation dosage, the impracticality of using them for postoperative follow-ups 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.

Gregory P. Nicholson, MD: Just as in any other arthroplasty (hip and knee), replacing the diseased joint surfaces is important, but so is mechanical alignment. In the shoulder, this is harder to evaluate due to anatomic issues. We use standard radiographic views for all patients — a true AP of the glenohumeral joint (Grashey view), outlet view and an axillary view. This provides the minimum imaging necessary. In all arthroplasty surgeries, we believe an advanced imaging study is necessary (CT or MRI). Many patients are referred in with an MRI already performed. This is acceptable. We prefer a CT scan as it shows bone more clearly than MRI.

With radiographs and CT or MRI, we make a qualitative determination of the pathologic wear pattern. The Walch classification is useful for this. However, we also quantitatively evaluate from those images the amount of retroversion and the available depth of the glenoid vault. The wear pattern or deformity is not symmetric and is usually posterio-inferior on the glenoid. The surgeon may have to evaluate multiple image cuts from superior to inferior to realize the wear.

A CT scan with 3-D reconstruction is helpful in cases of severe or post-traumatic deformity. The data are also needed for PSI, which is becoming more prevalent and user-friendly for the shoulder in the past year or so.

Tom R. Norris, MD: In each case, I now use a CT scan with 3-D reconstructions. This has been available in open source software, OsiriX. Three-dimensional reconstruction can be created using the DICOM images available on the CT scan disc under the setting of 3-D viewer 3-D MPR. This allows for corrections to be done in the plane of the scapula. The Walch classification has been the basis for viewing the 3-D axial cuts with the newer version delineating a B3 glenoid.

More recently, several companies have offered PSI and 3-D scapular reconstruction. The one I have chosen to use is IMASCAP, which recently has licensed the BLUEPRINT software through Tornier Inc. The surgeon can load the CT on his own computer and determine the angles of retroversion, inclination and bone loss. One can virtually trial prosthetic glenoid and base plate components, as well as ream, or add bone grafts in preoperative planning.

I have followed Walch’s 2013 published recommendations for reverse total shoulder arthroplasty (TSA) to treat primary glenohumeral arthritis in patients with a bi-concave glenoid. Currently, I correct up to 10° to 15° of retroversion with reaming. More than that, I will either use a humeral head bone graft with an anatomic or reverse shoulder prosthesis.

 

When performing an anatomic TSA in the absence of correcting the version, posterior subluxation is possible (Figures 3-5). Reaming through the subchondral bone to correct the glenoid retroversion risks premature glenoid component loosening, polyethylene wear debris and subsequent osteolysis.

Image: Norris TR

Joseph P. Iannotti, MD, PhD: We obtain AP radiographs in the plane of the scapula (Grashey view) and an axillary view in all patients. We obtain a CT scan to include the entire scapula with less than 1-mm cuts in all patients with asymmetric glenoid bone loss and any translation of the center of the humeral head in relation to the center of the glenoid. In our practice, this would result in approximately 80% of patients getting a CT scan.

All patients getting a CT scan have 3-D imaging and templating for preoperative planning. In all patients, the plane of the scapula is defined by three points (tip of the scapula, center of the glenoid and scapula trigonum) on the 3-D reconstruction. From this plane, three orthogonal 2-D images are made (axial, coronal and sagittal planes). The plane of the glenoid surface is defined by three points. Its relation to the plane of the scapula define glenoid version and inclination. The center of the humeral head is defined from a best fit sphere and its linear displacement defined from the center line of the scapular plane (humeral scapula alignment) and the center line of the glenoid plane (humeral glenoid alignment [HGA]) (Figure 6).

We use 3-D imaging and templating with standard instrumentation for approximately 80% of patients and PSI for those glenoids with the most severe glenoid bone deformity (Figures 7 and 8).

Image: Iannotti JP

Image: Iannotti JP

Image: Iannotti JP

Pearl: At what degree of retroversion or glenoid wear, if ever, do you decide to depart from standard procedures of reaming the glenoid to a neutral version and resort to other measures, such as bone grafting or glenoid implants, that have posterior augments?

Iannotti: Most patients have a native glenoid version of 6°. We correct patient retroversion of up to 15°, with asymmetric reaming to correct to 6° of retroversion. In patients older than 55 years with 20° to 35° of retroversion, we use an augmented glenoid component that builds up the posterior side with minimal bone removal on the anterior side.

For younger patients, we prefer bone grafting and use of a standard symmetric glenoid component. In patients with more severe glenoid bone loss, particularly in patients with severe retroversion and medial bone loss (C2 or B3 glenoids), we use bone grafting and reverse TSA. Most of these patients are elderly, and a reverse TSA provides a more reliable outcome with this degree of bone loss in this age group (Figures 9-12).

Image: Iannotti JP

Image: Iannotti JP

Image: Iannotti JP

Image: Iannotti JP

Nicholson: Recent investigations have shown there is a higher incidence of perforation of the glenoid wall and vault in simulated glenoid implantation scenarios when there is significant glenoid wear. Fifteen degrees of retroversion makes it difficult to ream down (lower the front) the glenoid to “catch up” to the wear defect. It does not leave enough vault for pegs or a keel. Placing the component in the retroverted position also creates perforation or severe mechanical stress on the implant.

The true magnitude of the wear may not be appreciated until there is an intra-operative evaluation. In patients with B1 or B2 glenoids with 10° to 15° of retroversion on advanced imaging and an intact rotator cuff, we are prepared to re-establish a more anatomic joint line by using a posterior glenoid bone graft technique (Figures 13 and 14). The wear pattern is not uniform and bone graft technique can address this, whereas an augmented component will need to make the defect uniform prior to implantation.

Thus, the options are:

• re-establishing a more anatomic joint alignment with either “raising the back” by using a posterior glenoid bone graft technique or augmented glenoid components;
• “lowering the front” by reaming down the front high side to catch up to the defect and then implanting a glenoid if possible; or doing a hemiarthroplasty in this scenario; or
• utilizing a reverse TSA for the semi-constrained aspect and thus preventing any posterior subluxation.

Norris: In bone grafting the deficient posterior glenoid and placing an anatomic TSA, I have experienced more stiffness than usual and, in some cases, earlier glenoid implant loosening or recurrence of the posterior subluxation. In this case, using the humeral head as a graft, the original reduction was satisfactory with good range of motion and comfort. However, by 18 months, the posterior subluxation recurred, causing both glenoid loosening and metallosis on the posterior screws. This propensity for recurrence of the posterior subluxation in anatomic TSA is well-described by Denard and Walch. Revision to a reverse shoulder arthroplasty (RSA) has remained stable and pain-free with excellent function at 3 years (Figures 15-19).

Image: Norris TR

Matsen: Except in cases of true glenoid dysplasia, we have not found it necessary to depart from our standard approach to arthroplasty. In the treatment of glenoid retroversion, we do not use reaming of the high side, glenoid bone grafts, posteriorly augmented glenoid components or PSI, as these are unnecessary to achieve stability of the reconstruction. A reverse TSA 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 TSA — is to conservatively ream the glenoid to a single concavity without trying to “normalize” version (Figure 20). As a result, the amount of glenoid bone removed by reaming is small. The humeral head is balanced on the glenoid by using a humeral head size that offers 50% posterior translation of the head and 60° of internal rotation with the arm in 90° of abduction.

Image: Matsen FA III

If necessary to achieve posterior stability, we use an anteriorly eccentric humeral head component and/or a rotator interval plication.

Pearl: Is there a role for hemiarthroplasty, with or without reaming the glenoid, in the presence of advanced glenoid wear?

Matsen: It is important to distinguish a hemiarthroplasty, which by definition does not address the glenoid pathology, from a ream-and-run, which by definition addresses both sides of the joint. Glenohumeral OA involves, by definition, both the glenoid and the humeral sides of the joint. For the average patient, we recommend a TSA 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 and for those who wish to avoid the risks of failure seen with a plastic glenoid component. I would steer clear of a ream-and-run in patients with inflammatory arthritis, smokers, narcotic pain medication, depression or lack of convincing motivation

I consider a ream-and-run for patients 18 years to 80 years of age. We have had success with the ream-and-run on glenoids with as much as 40° of retroversion.

Nicholson: The determining factor in the decision is patient selection. The surgeon must discuss the patient’s lifestyle, expectations, occupation, gender, age and activity level. All of these issues will help make an appropriate choice.

The role of hemiarthroplasty for OA with advanced glenoid wear has diminished, but still has a place. Again, it is patient selection. Patients younger than 50 years who have advanced OA can be considered, as we know that polyethylene glenoids will wear or loosen in this population. A definitive type C glenoid (dysplasia) is an indication for hemiarthroplasty.

Norris: The role of hemiarthroplasty in my practice is still for osteonecrosis or early OA in young patients without advanced changes in the glenoid side. In a selected group of patients, such as bodybuilders who would be expected to loosen the glenoid prematurely, I would consider gentle reaming of the glenoid as long as the subchondral bone can be preserved. Otherwise, I would prefer a total shoulder or reverse shoulder prosthesis for arthritis with eccentric glenoid bone loss. The only angled glenoids I have had experience with were those that were referred in and loose.

Iannotti: We perform hemiarthroplasty in patients younger than 40 years and would do some glenoid recontouring when asymmetric bone loss was mild to moderate (3 mm to 5 mm). In severe bone loss, even in a young patient, we prefer bone grafting and placing a symmetric glenoid component to protect the graft.

Pearl: If not answered in the previous question, is there a role for RSA in a patient with OA and advanced glenoid wear?

Matsen: We would consider a RSA in an elderly inactive patient with posterior instability, but not in our usual active population.

Iannotti: As stated in the previous question, in patients with severe glenoid bone loss resulting in severe medialization of the humeral head, we prefer a total RSA with use of the humeral head as a graft, even in patients with an intact rotator cuff.

Nicholson: For patients older than 65 years, a total RSA can be a good option. For example, a retired, low-demand, 75-year-old patient with a B2 glenoid and severe OA may do best with a total RSA. However, in an active man in his 50s with early OA and an intact rotator cuff with posterior glenoid wear — which is a common male pattern of degenerative joint disease — a total RSA would not be the best choice. We would want to restore more native joint kinematics with native bone, if necessary, and this patient would be a candidate for TSA with posterior glenoid bone grafting.

Norris: I now routinely use a reverse shoulder prosthesis for patients with OA and a B2 glenoid when there is 75% to 80% of posterior subluxation or glenoid bone loss that cannot be corrected by reaming as recommended by Walch. This has become my preference during the past 10 years, with none of these shaped humeral head bone grafts to the glenoid having loosened or gone onto nonunion. Unlike anatomic shoulder arthroplasties, none have subluxed posteriorly. The humeral head in a primary case provides a bone graft that can be shaped to fit the B2 and C glenoid wear patterns. By flattening the anterior high side, the shaped graft restores the lateral glenoid offset and version.

 

Figures 21 through 26 show a case where a long post or threaded base plate was recommended to engage the native scapula for better fixation. The base plate with a post can be impacted. When using the threaded post base plate, the graft is held with a towel clip to prevent rotation at the time of final compression.

 

For patients with the more severe B2 and B3 glenoid wear patterns, I feel I have a more predictable operation, even in a younger 50-year-old patient with a reverse shoulder prosthesis, than I do with an anatomic shoulder prosthesis. With longer follow-up, the reverse shoulder prosthesis has remained stable and has fared better than the anatomic TSA when one treats patients with severe posterior glenoid wear.

• References:
• Denard PJ, et al. J Shoulder Elbow Surg. 2013;doi:10.1016/j.jse.2013.06.017.
• Mizuno N, et al. J Bone Joint Surg Am. 2013;doi:10.2106/JBJS.L.00820.

• For more information:
• Joseph P. Iannotti, MD, PhD, can be reached at The Cleveland Clinic A-41, 9500 Euclid Ave., Cleveland, OH 44195; email: iannotj@ccf.org.
• Michael Pearl, MD, can be reached at Kaiser Permanente, LAMC, Clinical Professor, USC, 4760 Sunset Blvd., Los Angeles, CA 90027; email: michael.l.pearl@kp.org.
• Frederick A. Matsen III, MD, can be reached at the Department of Orthopaedics and Sports Medicine, University of Washington, 4245 Roosevelt Way N.E., Seattle, WA 98105; email: matsen@uw.edu.
• Gregory P. Nicholson, MD, can be reached at Rush University Medical Center, Midwest Orthopedics at Rush, 1611 W. Harrison St., Suite 300, Chicago, IL 60612; email: gregory.nicholson@rushortho.com.
• Tom R. Norris, MD, can be reached at San Francisco Shoulder, Elbow & Hand Clinic; 2351 Clay St., Suite 510, San Francisco, CA 94115; email: tnorris@tomnorris.com

Disclosures: Iannotti reports he has stock or stock options in Custom Orthopaedic Solutions; is a paid consultant and presenter and receives IP royalties from DePuy Synthes; receives IP royalties from Integra, Tournier and Zimmer; and receives publishing royalties from Wolters Kluwer Health. Matsen reports he received royalties from Elsevier for authorship/editorship of The Shoulder. Nicholson reports he is a consultant and designer for Tornier and receives royalties from Innomed; and receives research and educational support from Tornier, Smith & Nephew, Arthrex and Ossur. Norris reports he is a designer, consultant and stockholder for Tornier and also receives fellowship support from Tornier. Pearl reports no relevant financial disclosures.