Franklin and colleagues studied seven total shoulder arthroplasties with major glenoid lucency or component translation to find which factors accompanied glenoid loosening.
University of Washington series. Loosening cases seen a mean of 30 months (14 to 44) after arthroplasty. Compared with 16 consecutive intact‑cuff shoulders followed an average of 5 years.
Methods
Design
Case review with comparison groups
Patients
30 shoulders in three groups
Group 1: 7 cuff‑deficient, loose glenoid
Group 2: 7 cuff‑deficient, no loosening
Group 3: 16 consecutive, intact cuff
Basis
Location and width of lucency around the glenoid component
Component translation or dislocation
GHCC distance: glenoid component center to humeral head center, parallel to the stem
Key Findings
All 7 loosening cases had rotator cuff deficiency: 6 had severe tears that could not be fully repaired at surgery, and 1 tore the cuff within a year.
Upward humeral migration, measured as the glenohumeral center‑to‑center (GHCC) distance, correlated significantly with radiographic glenoid class across all groups (r² = 0.25).
None of the 16 consecutive intact‑cuff controls showed glenoid loosening at an average of 5 years.
Mean GHCC distance rose from 4.7 to 25.4 mm in the loosening group and from 5.9 to 18.6 mm in cuff‑deficient shoulders without loosening, but only from 3.1 to 4.5 mm with an intact cuff.
Only 1 of the 6 loose glenoids had lucency on immediate postoperative films, and every removed component showed cement interdigitated with trabecular bone.
Board pearl
In the "rocking horse" glenoid, the glenoid component tips superiorly as the humeral component rides upward in a cuff‑deficient shoulder, which the authors suggest may contribute to loosening.
Authors' conclusion
Upward riding of the prosthetic humeral head in patients with rotator cuff deficiency may contribute to loosening of the glenoid component in total shoulder arthroplasty.
Franklin and colleagues studied seven total shoulder arthroplasties with major glenoid lucency or component translation to find which factors accompanied glenoid loosening.
University of Washington series. Loosening cases seen a mean of 30 months (14 to 44) after arthroplasty. Compared with 16 consecutive intact‑cuff shoulders followed an average of 5 years.
Methods
Design
Case review with comparison groups
Patients
30 shoulders in three groups
Group 1: 7 cuff‑deficient, loose glenoid
Group 2: 7 cuff‑deficient, no loosening
Group 3: 16 consecutive, intact cuff
Basis
Location and width of lucency around the glenoid component
Component translation or dislocation
GHCC distance: glenoid component center to humeral head center, parallel to the stem
Key Findings
All 7 loosening cases had rotator cuff deficiency: 6 had severe tears that could not be fully repaired at surgery, and 1 tore the cuff within a year.
Upward humeral migration, measured as the glenohumeral center‑to‑center (GHCC) distance, correlated significantly with radiographic glenoid class across all groups (r² = 0.25).
None of the 16 consecutive intact‑cuff controls showed glenoid loosening at an average of 5 years.
Mean GHCC distance rose from 4.7 to 25.4 mm in the loosening group and from 5.9 to 18.6 mm in cuff‑deficient shoulders without loosening, but only from 3.1 to 4.5 mm with an intact cuff.
Only 1 of the 6 loose glenoids had lucency on immediate postoperative films, and every removed component showed cement interdigitated with trabecular bone.
Board pearl
In the "rocking horse" glenoid, the glenoid component tips superiorly as the humeral component rides upward in a cuff‑deficient shoulder, which the authors suggest may contribute to loosening.
Authors' conclusion
Upward riding of the prosthetic humeral head in patients with rotator cuff deficiency may contribute to loosening of the glenoid component in total shoulder arthroplasty.