Simovitch and colleagues examined whether inferior scapular notching after Delta III reverse shoulder arthroplasty affects clinical outcome and which glenoid component position measures predict it.
77 consecutive shoulders in 76 patients with irreparable cuff deficiency, treated at Balgrist, Zürich, and followed at least 24 months.
Methods
Design
Consecutive series, single surgeon
Implanted 1995 to 2003
Prognostic Level II
Data source
Single academic center, Uniklinik Balgrist, Zürich
Patients
107 eligible shoulders, of which 77 in 76 patients had 2 years of follow‑up without early revision
Irreparable cuff tear with pseudoparesis (58) or cuff tear arthropathy (19)
Exposure
Delta III reverse total shoulder arthroplasty
Craniocaudal glenosphere position (peg‑glenoid rim distance)
Postoperative prosthesis‑scapular neck angle
Follow-up
Minimum 24 months (mean 44)
Outcomes
Inferior, posterior and anterior notching
Relative Constant score
Subjective shoulder value
Active flexion and abduction
Key Findings
Inferior notching developed in 34 of 77 shoulders (44%), compared with posterior notching in 23 (30%) and anterior notching in 6 (8%).
Glenosphere height (r = 0.654) and the prosthesis‑scapular neck angle (r = 0.667) both correlated with inferior notching, but height carried about eight times the influence.
Every inferior notch appeared within 14 months of surgery and stopped progressing at an average of 18 months.
Most inferior notches were minor (Nerot grade 1 or 2), and the 2 that reached under the baseplate had caused no loosening or failure after a further average of 16 months.
Posterior notching was linked to greater external rotation (31° vs 17° postoperatively), and neither posterior nor anterior notching significantly affected clinical outcome with the numbers studied.
Shoulders with inferior notching had a lower mean relative Constant score than those without (72% vs 83%, p = 0.028), with lower subjective shoulder value, strength and motion.
Board pearl
A notching index (prosthesis‑scapular neck angle × 0.13 + peg‑glenoid rim distance in mm) above 35 predicted inferior notching with 91% sensitivity and 88% specificity.
Authors' conclusion
Inferior scapular notching after reverse total shoulder arthroplasty adversely affects the intermediate-term clinical outcome. It can be prevented by optimal positioning of the glenoid component.
Simovitch and colleagues examined whether inferior scapular notching after Delta III reverse shoulder arthroplasty affects clinical outcome and which glenoid component position measures predict it.
77 consecutive shoulders in 76 patients with irreparable cuff deficiency, treated at Balgrist, Zürich, and followed at least 24 months.
Methods
Design
Consecutive series, single surgeon
Implanted 1995 to 2003
Prognostic Level II
Data source
Single academic center, Uniklinik Balgrist, Zürich
Patients
107 eligible shoulders, of which 77 in 76 patients had 2 years of follow‑up without early revision
Irreparable cuff tear with pseudoparesis (58) or cuff tear arthropathy (19)
Exposure
Delta III reverse total shoulder arthroplasty
Craniocaudal glenosphere position (peg‑glenoid rim distance)
Postoperative prosthesis‑scapular neck angle
Follow-up
Minimum 24 months (mean 44)
Outcomes
Inferior, posterior and anterior notching
Relative Constant score
Subjective shoulder value
Active flexion and abduction
Key Findings
Inferior notching developed in 34 of 77 shoulders (44%), compared with posterior notching in 23 (30%) and anterior notching in 6 (8%).
Glenosphere height (r = 0.654) and the prosthesis‑scapular neck angle (r = 0.667) both correlated with inferior notching, but height carried about eight times the influence.
Every inferior notch appeared within 14 months of surgery and stopped progressing at an average of 18 months.
Most inferior notches were minor (Nerot grade 1 or 2), and the 2 that reached under the baseplate had caused no loosening or failure after a further average of 16 months.
Posterior notching was linked to greater external rotation (31° vs 17° postoperatively), and neither posterior nor anterior notching significantly affected clinical outcome with the numbers studied.
Shoulders with inferior notching had a lower mean relative Constant score than those without (72% vs 83%, p = 0.028), with lower subjective shoulder value, strength and motion.
Board pearl
A notching index (prosthesis‑scapular neck angle × 0.13 + peg‑glenoid rim distance in mm) above 35 predicted inferior notching with 91% sensitivity and 88% specificity.
Authors' conclusion
Inferior scapular notching after reverse total shoulder arthroplasty adversely affects the intermediate-term clinical outcome. It can be prevented by optimal positioning of the glenoid component.