Three recent publications support the concept that conventional anatomic total shoulder arthroplasty (TSA) without augmented glenoid components can yield outcomes for type B2, type C and retroverted glenoids that are equivalent to those for type A1 glenoids.
(1) Outcomes of anatomic shoulder arthroplasty performed on B2 vs. A1 type glenoids
These authors compared outcomes of TSA performed on A1 glenoids (n=178) and B2 glenoids (n-111) treated with asymmetric glenoid reaming at a minimum of 2-years (mean 40 months).
More men presented with a B2 glenoid (80 of 111; 72%) compared with A1 (101 of 178; 57%).
Both groups had similar Constant Strength scores preoperatively but the B2 group improved significantly more at final follow-up.
The Total Constant score was also significantly better at follow-up in the B2 glenoid group.
All other Constant subscales, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Single Assessment Numerical Evaluation (SANE) measures showed no significant differences between the A1 and B2 glenoid groups.
A similar proportion of patients rated their satisfaction as either very satisfied or satisfied between the A1 and B2 (glenoid types.
Lazarus scores were also similar between the A1 and B2 groups as were the rates of humeral radiolucent lines and humeral osteolysis.
Postoperative complications occurred in 8 shoulders (7%) in the B2 group and 8 shoulders in the A1 group (5%). The revision rates were also similar between the B2 (6 patients; 5%) and A1 (6 patients; 3%) groups.
(2) Early to midterm outcomes of anatomic shoulder arthroplasty performed on dysplastic (type C)
These authors hypothesized that TSA performed for Walch type C dysplastic glenoids with standard glenoid components can reliably produce successful results at short to midterm follow-up. They identified 29 patients that met inclusion criteria of a preoperative Walch type C dysplastic glenoid, treatment with TSA using standard (non-augmented) glenoid components and a minimum of 2-years clinical. These patients were matched to a cohort of 58 patients with a type A1 glenoid and minimum of 2-years clinical follow-up. The mean follow-up for this study was 4.5 years.
Baseline measures were not significantly different between the Walch type C dysplastic group and the matched type A1 cohort.
The Walch type C group had no significant differences in ASES score, ASES pain, or SANE score compared to the matched type A1 cohort.
The complication rate of patients with a type C glenoid was 14% (4 of 29) with a 7% (2 of 29) revision rate. Similarly, the complication rate for the A1 matched cohort was 17% (10 of 58) with a 12% (7 of 58) revision rate.
Both groups had high patient satisfaction without statistical differences.
There were no differences in the rate of radiographic lucencies or Lazarus scores.
These authors sought to determine if glenoid components implanted in 15 degrees or greater retroversion had (1) less improvement in the Simple Shoulder Test (SST) score and lower SST scores, (2) higher percentages of central peg lucency, higher Lazarus radiolucency grades, higher mean percentages of posterior decentering, and more frequent central peg perforation; or (3) a greater percentage having revision for glenoid component failure compared with patients with glenoid components implanted in less than 15 retroversion.
The study included 71 TSAs, comparing the 21 in which the glenoid component was implanted in 15 degrees or greater retroversion (mean ± SD, 20.7 ± 5.3) with the 50 in which it was implanted in less than 15 retroversion (mean ± SD, 5.7 ± 6.9).
At a minimum 2-year followup (mean ± SD, 2.5 ± 0.6 years; range, 18–36 months), the mean (± SD) improvement in the SST for the retroverted group was not inferior to that for the nonretroverted group.
The mean difference in improvement, the percent of maximal possible improvement (%MPI), and the 2-year SST scores for the two groups were not significantly different.
No patient in either group reported symptoms of subluxation or dislocation.
The radiographic results for the retroverted glenoid group were similar to those for the nonretroverted group with respect to central peg lucency, average Lazarus radiolucency scores, and the mean percentage of posterior humeral head decentering.
The percentage of patients with retroverted glenoids undergoing revision (0 of 21) was not
inferior to the percentage of those with nonretroverted glenoids (three of 50).
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