Scapular notching: Recognition and strategies to minimize clinical impact.
BACKGROUND
Scapular notching is a unique complication of Grammont-style reverse total shoulder arthroplasty. While reverse total shoulder arthroplasty has revolutionized the treatment of pseudoparalysis secondary to cuff tear arthropathy, the implications of scapular notching with regard to patient function and implant stability remain unclear.


OBJECTIVE
We reviewed literature to determine the etiology and incidence, radiographic progression and effect on implant stability, relationship with postoperative function, and risk factors for the development of scapular notching.


METHODS
We reviewed PubMed, the Cochrane Central Register of Controlled Trials, and EMBASE with the terms "reverse total shoulder arthroplasty" and "scapular notching." Inclusion criteria were a level of evidence of IV (or better). Twenty-four articles were selected after manual review.


RESULTS
Scapular notching after reverse total shoulder arthroplasty is due to repetitive contact between the polyethylene of the humeral component and the inferior scapular neck during adduction, leading to erosion of the scapular neck, polyethylene wear, joint inflammation, and potential implant loosening. Scapular notching appears between 6 and 14 months postoperatively, with an incidence of 44% to 96%. Radiographic progression and effect on patient function remain controversial. Predictors of scapular notching include surgical approach, glenoid wear, preoperative diagnosis, infraspinatus muscle quality, cranial-caudal positioning, and tilt of the glenosphere.


CONCLUSIONS
Improved understanding of the etiology and risk factors for scapular notching will lead to refinement in implant technology and surgical technique that may translate into improved patient function and implant longevity for Grammont-style reverse total shoulder arthroplasty.
Division of Sports Medicine, Rush University Medical Center, Chicago, IL, USA. orthonick@comcast.net
Gregory P
GP
Nicholson
Eric J
EJ
Strauss
Seth L
SL
Sherman
D019643:Arthroplasty, Replacement / Q000009:adverse effects* / Q000295:instrumentation; D001696:Biomechanical Phenomena; D006801:Humans; D007595:Joint Prosthesis; D053580:Muscle Strength; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000517:prevention & control*; D011474:Prosthesis Design; D011859:Radiography; D016059:Range of Motion, Articular; D020127:Recovery of Function; D018570:Risk Assessment; D012307:Risk Factors; D012540:Scapula / Q000000981:diagnostic imaging / Q000293:injuries*; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome