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Scapular Notching in Reverse Total ShoulderArthroplasty: Now What?

John P. Taliaferro MD., Lynn A. Crosby MD.

PII: S1045-4527(14)00044-3DOI: http://dx.doi.org/10.1053/j.sart.2014.02.008Reference: YSART50583

To appear in:Semin Arthro

Cite this article as: John P. Taliaferro MD., Lynn A. Crosby MD., Scapular Notching inReverse Total Shoulder Arthroplasty: Now What?,Semin Arthro , http://dx.doi.org/10.1053/j.sart.2014.02.008

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Scapular Notching in Reverse Total Shoulder Arthroplasty: Now What?

Authors:

1. John P. Taliaferro, MD. Medical College of Georgia, Georgia Regents University, Augusta, GA

2. *Lynn A. Crosby, MD. Department of Orthopaedics, Division of Shoulder Surgery, Medical College of Georgia, Georgia Regents University, Augusta, GA

Department of Orthopaedic Surgery, Medical College of Georgia, Georgia Regents University, 937 15th St. , Augusta, GA. 30912

Institution:

From the Medical College of Georgia, Georgia Regents University.

Address:

*Corresponding Author: Lynn A. Crosby, MD, Department of Orthopaedic Surgery, Georgia Regents University, 937 15th St., Augusta, GA 30912. Email: lycrosby@gru.edu

 

Abstract:

Scapular notching is a well known complication of reverse total shoulder arthroplasty.

While early reports revealed no ill effects on clinical outcomes, later research has shown

decreased range of motion, decreased strength, lower Constant scores, and higher pain scores. It

appears that lowering the glenosphere on the glenoid decreases contact between the humeral

component and the inferior bony pillar, decreasing the rate and grade of notching. Once notching

occurs after reverse total shoulder arthropasty , it appears that close observation in an

asymptomatic patient is sufficient. Revisions in symptomatic patients require debridement, bone

grafting, and baseplate augments.

 

 

 

 

Introduction:

Stemming from Kobel's first reverse total shoulder arthroplasty design in 1972, a myriad

of reverse shoulder prosthesis designs have followed since the 1970s [1]. These early implants

were a constrained design, requiring a fixed center of rotation leading to high rates of mechanical

failures, usually on the glenoid side. This lead to their eventual removal from the United States

market in the 1980s. Grammont continued to seek a solution to this mechanical problem, and in

1985 released an inverted version of the constrained prosthesis designs of the 1970s (Fig 1).

Lowering and medializing the center of rotation, Grammont increased the moment arm of the

deltoid and limited the shear forces responsible for the earlier glenoid failures.

Complications arose with successful reverse total shoulder prostheses. Bohsali et al. [2]

described many, including glenosphere dissociation, fracture, infection, glenohumeral

dislocation, nerve injury, postoperative hematoma, and scapular notching. With the success of

Grammont's early Delta III design came the complication of what has been described as scapular

notching, a loss of bone on the inferior neck of the scapula that has been attributed to

mechanical contact of the humeral component with the inferior scapular neck and subsequent

bone that is best seen on an AP radiograph. [3,4].

This report will focus on scapular notching after reverse total shoulder arthroplasty,

causes, what can be done surgically to prevent notching, and techniques for surgical revisions.

Notching: Now What?

Grammont's early Delta III design had a non-anatomic humeral inclination angle of 155°

(compared to the anatomical average of 41°) and a short neck on the reverse glenoid component

[5]. While the design proved excellent in its functional results, it caused impingement on the

inferior scapular neck, leading to notching (Fig 2). To better understand the extent of notching

that occurs, we use the Nerot-Sirveaux grading scale (Fig 3). Grades 1 and 2 are likely secondary

to the impingement of the prosthesis while grades 3 and 4 are due to both impingement and

osteolysis . The process of osteolysis occurs from polyethene debris from the liner and a

secondary macrophage migration, infiltration, and lastly ingestion of the debris and bone

fragments [6].

As scapular notching has become a well-known complication, physicians have been

increasingly concerned about the effects of notching on clinical outcomes and possible

preventions that could be taken in the operating room. While early reports by Sirveaux et al. and

Werner et al. showed radiographic evidence of notching, neither study found notching

correlating with a lower Constant score or clinical deterioration. [7,8] Simovitch et al.

contradicted these findings. [9] Their report showed that notching occurred rapidly in the first 14

months and finally stabilized around 18 month. This notching did lead to lower Constant scores

and higher pain scores along with decreased range of motion and strength on further clinical

follow-up .

Following the negative outcomes related to scapular notching, the practicing shoulder

surgeon should be concerned with the prevention of poor outcomes. Several strategies have

emerged in an effort to prevent the detrimental effects of notching. One approach would be to

add an inferior tilt to the glenosphere. However, Edwards et al. reported no difference in the rate

of notching between tilted and normal set glenospheres. [10] Another strategy has been to move

the glenosphere inferiorly on the glenoid. Roche et al. led a multicenter study reporting that

lowering the glenosphere had a scapular notching rate of only 9.7% with no grades over 2 (Fig

4). [11] With this knowledge, different prostheses were made that lowered the glenosphere in

the design. However, even the newer designs did not lower the glenosphere sufficiently,

requiring surgeons to secondarily adjust the glenosphere placement on the glenoid to avoid

notching.

Having a lowered glenosphere still does not always prevent advanced glenoid notching,

but slows down the rate of notching substantially [11]. It is known that many patients are noted

to have advanced notching without symptoms. These patients are followed closely and

monitored for advancement of the notching or significant changes in the position of the

components. Once patients become symptomatic or significant shifting has occurred, surgical

intervention is required [12]. Without intervention, the glenoid component will become unstable

with progressive migration of the glenosphere post.

When revisions are required, bone quality may guide treatment options [13]. Using the

Antuna Classification system for glenoid deficiency, the shoulder surgeon is able to classify the

extent and location of the bone deficiency. Bone grafting is possible for repair, but a very

thorough debridement must be performed. With more central erosion of the glenoid, extended

cage glenoid baseplate bridges have been produced in order to allow the peg to extend into native

bone. This design also allows for bone graft to be placed to fill the defect (Fig 5). Some

glenosphere design changes have also been developed for more centrally eroded glenoids that

lateralize the humerus without the need for large bone grafts . This lateral offset may help to

restore the anatomic position of the tuberosities and may decrease the risk of acromial fractures

(Fig 6). Other improvements have been developed to usurp the need for bone graft. These

product designs include superior and posterior augmented metaglenes that fill in these defects

with built up metal continuous with the baseplate that allows for stability in these bone deficient

cases (Fig 7).

Conclusions:

Scapular notching is a well known complication of reverse total shoulder arthroplasty. It

has been shown to negatively affect patient outcomes in range of motion, strength, and pain

scores if progressing to advanced stages. To prevent this complication, lowering of the

glenosphere appears to be the best method to slow notching and improve patient outcomes.

Surgeons must take into consideration that even the use of a lowered prosthesis may not lower

the glenosphere sufficiently, and may have to place the glenosphere additionally lower to

decrease notching. If revision is required, aggressive debridement of all the polyethylene debris,

and either the use of bone grafting or metal augmentation to correct the bone deficient glenoid

may be required. Longer term follow up will be required to determine if these changes in

prosthesis design and the use of augments will make a difference in clinical outcome in the

future.

References

(1) Katz D, O'Toole G, Cogswell L, Sauzieres P, Valenti P. A history of the reverse shoulder

prosthesis. Int J Shoulder Surg. 2007;1:108-13.

(2) Bohsali KI, Wirth MA, Rockwood Jr CA. Complications of total shoulder arthroplasty. J

Bone Joint Surg Am. 2006;88(10):2279-92.

(3) DeWilde L, Mombert M, Van Petegem P, Verdonk R. Revision of shoulder replacement with

a reversed shoulder prosthesis (Delta III): report of five caes. Acta Orthop Belg,

2001;67:348-53

(4) Sirveaux F. Grammont prosthesis in the treatment of shoulder arthroplasties with massive

cuff tear. Multicenter series of 42 cases (in French) Medical doctor thesis Nancy I

University (France, 1997). In: Levigne C, Garret J, Boileau P, Alami G, Favard L,

Walch G. Scapular notching in reverse shoulder arthroplasty: is it important to avoid

it and how? Clin Orthrop Relat Res 469(9):2512-2520, 2011.

(5) Robertson DD, Yuan J, Bigliani LU, Flatow EL, Yamaguchi K. Three-dimensional analysis

of the proximal part of the humerus: relevance to arthroplasty. J Bone Joint Surg Am.

2000;82-A(11):1594-602.

(6) Nicholson G, Strauss E, Sherman S. Scapular notching recognition and strategies to minimize

clinical impact. Clin Orthrop Relat Res. 2011;469(9):2512-2520,2011.

(7) Sirveaux F, Favard L, Oudet D, Huqet D, Walch G, Mole D. Grammont inverted total

shoulder arthroplasty in the treatment of glenohumeral osteoarthritis with massive rupture

of the cuff. J Bone Joint Surg Br. 2004;86-B:388-95.

(8) Werner C, Steinmann P, Gilbart M, Gerber C. Treatment of painful pseudoparesis due to

irreparable rotator cuff dysfunction with the Delta III reverse-ball-and-socket total

shoulder prosthesis. J Bone and Joint Sur Am. 2005;87A:1476-86.

(9) Simovitch RW, Zumstein MA, Lohri E, Helmy n, Gerber C. Predictors of scapular notching

in patients managed with Delta III reverse total shoulder replacement. J Bone Joint Surg

Am. 2007;89(3):588-600.

(10) Edwards TB, Trappery GJ, Riley C, O'Connor DP, Elkhousy HA, Gartsman GM. Inferior

tilt of the glenoid component does not decrease scapular notching in reverse shoulder

arthroplasty: results of a prospective randomized study. J Shoulder Elbow Sur.

2012;21)5):641-6.

(11) Roche C, Wright T, Flurin PH, Grey S, Jones R, Routman H, et al: Scapular notching

radiographic analysis: recommendations for glenoid plate positioning and glenosphere

overhang in male and female patients, Submitted to ORS.

(12) Florie E and Crosby L. Scapular Notching: Danger ahead? Seminars in Arthroplasty. 24

(2013) 24-27.

(13) Antuna SA, Sperling JW, Cofield RH, Rowland CM. Glenoid revision surgery after total

shoulder arthroplasty. J Shoulder Elbow Surg 2001;10:217-24.

Figure Legends

Figure 1- Newest version of Grammont's Delta III Prosthesis (2004)

Figure 2- Grade 4 scapular notching.

Figure 3- Nerot-Sirveaux staging scale for scapular notching.

Figure 4- (A and B) No scapular notching at postoperative time points: 1 week and 23 months with lowering the implanted position of the glenosphere.

Figure 5- Extended Cage Glenoid Plate. The extended cage allows for the bone graft to fill the defect while also extending into native bone.

Figure 6-Lateralized glenospheres. Help to restore anatomic positions of the tuberosities, decreasing the rate of acromial fractures.

Figure 7- Metal solution-augmented baseplates.

Fig 1

Fig 2

Fig 3

 

 

 

 

Grade 1‐ Confined to the pillars 

Grade 2‐ Contact with lower screw 

Grade 3‐ Over the lower screw 

Grade 4‐ Extended under the baseplate 

Fig 4a

Fig 4b

Fig 5

Fig 6

Fig 7