These authors describe the use of an anteriorly offset humeral head component to address severe posterior subluxation associated with the Walch B2 glenoid deformity, allowing the proximal humerus to remain in a relatively posterior position while the prosthetic humeral head remains well-centered on the glenoid.
They retrospectively reviewed a series of 20 patients with a B2 glenoid at an average of 48 months after TSA with the prosthetic eccentric humeral head rotated anteriorly for excessive posterior subluxation noted intraoperatively (note that the need for this component was not determined on the basis of preoperative 3D planning).
In their practice glenoid deformities were managed using high-side (anterior) corrective reaming with a goal to ream to within approximately 10-15 of normal anatomic glenoid version.
Mean VAS (P < .0001), ASES (P < .0001), and SST (P < .0001) scores improved significantly.
Using the Lazarus classification for glenoid loosening, 5 patients had grade 1 lucency and 2 had grade 2 lucency at a mean of 24 months' follow-up.
The remaining 13 patients had no glenoid lucencies. Radiographic decentering was reduced from a mean of 9.9% ± 5.7% preoperatively to 0.5% ± 3.0% postoperatively (P < .001).
There were no cases of revision surgery.
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The use of the anteriorly eccentric humeral head is discussed in a prior article, the abstract of which is shown below.Management of intraoperative posterior decentering in shoulder arthroplasty using anteriorly eccentric humeral head components
Posterior humeral decentering presents a challenge in glenohumeral arthroplasty.
Soft tissue releases and osteophyte resection can lead to intraoperative decentering not evident preoperatively. Inferior outcomes result if decentering is not addressed as a part of the arthroplasty. When there is >50% posterior subluxation of the humeral head on passive elevation of the arm at surgery, we have used an anteriorly eccentric humeral head component to improve centering of the humeral articular surface on the glenoid.
Methods: We reviewed the 2-year outcomes for 33 shoulder arthroplasties in which anteriorly eccentric humeral heads were used to manage posterior decentering identified at surgery.
Methods: We reviewed the 2-year outcomes for 33 shoulder arthroplasties in which anteriorly eccentric humeral heads were used to manage posterior decentering identified at surgery.
Rotator interval plication was performed in 16 cases as an adjunctive stabilizing procedure. Shoulders were evaluated preoperatively and postoperatively with the Simple Shoulder Test (SST). Radiographic centering was characterized before surgery and at follow-up on standardized axillary radiographs with the arm held in a position of functional elevation.
Results: With the anteriorly eccentric head component, preoperative radiographic humeral decentering was reduced from 10.4% to 0.9% postoperatively.
SST scores improved from 4.8 to 10.0.
Preoperative posterior humeral head decentering did not correlate with preoperative glenoid version.
In contrast to the article referenced above, no attempt was made to change glenoid version. Glenoid retroversion was 19.8° preoperatively and 15.5° postoperatively.
Conclusion: In both of these papers, posterior decentering was assessed at surgery while trialing anatomic head components. If standard trial components allow posterior decentering, this can be addressed by replacing the anatomic humeral head with an anteriorly eccentric humeral head component. Note that this decision is not made on the basis of preoperative 3D planning.
Conclusion: In both of these papers, posterior decentering was assessed at surgery while trialing anatomic head components. If standard trial components allow posterior decentering, this can be addressed by replacing the anatomic humeral head with an anteriorly eccentric humeral head component. Note that this decision is not made on the basis of preoperative 3D planning.
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