These authors point out that osteoarthritis of the glenohumeral joint is often associated with posterior glenoid wear. They report their results in 68 primary anatomic total shoulders peformed with an 8 degree posteriorly augmented glenoid component on patients with a Walch B glenoid deformity.
The preoperative shoulder function was not different among the three types of B glenoids
On average, patients experienced significant improvements in pain and function following the TSA and 90% of patients exceeded the minimal clinically important difference threshold for the clinical outcome metric scores and ROM measures.
The post operative scores were similar among the three types.
The article does not report the degree of centering of the humeral head on the face of the glenoid before or after surgery. Instead, it reported on the position of the humeral head in relation to the plane of the scapula. While this is sometimes referred to as "subluxation", it does not indicate the critical relationship of the humeral head to the glenoid (note that the standard definition of "subluxation" is partial dislocation with separation of the joint surfaces).
Two patients reported axillary neurapraxia, each approximately 6 months after the procedure.
Six of 60 patients had a radiolucent humeral line, for a rate of 10.0%, higher in the patients with B2 glenoids. Almost half (43.6%) of the B2 glenoids had radiolucent lines.
Of 57 patients, 21 (36.8%) were observed to have a radiolucent glenoid line, with an average radiographic glenoid line score of 0.9 1.5 (grade 1 in 8, grade 2 in 4, grade 3 in 5, and grade 5 in 4). B2 glenoids had a lucent line grade of 1.2, at least 3 times greater than for the B1 and B3 glenoid types (0.4 and 0.2).
At an average of 50 months, two of the 46 (4%) patients with augmented glenoids who had B2 glenoids underwent revision for aseptic glenoid loosening.
Comment: This study of posterior augmented glenoids demonstrated an increased rate of lucent lines, glenoid component loosening and revision in shoulders with B2 glenoids treated with a posteriorly augmented glenoid.
This study should be viewed in light of several other recent articles.
Outcomes of anatomic total shoulder arthroplasty in patients with excessive glenoid retroversion: a case-control study
These authors used a case-controlled study to evaluate the effect of severe preoperative glenoid retroversion on clinical and radiographic total shoulder (TSA) outcomes using a standard non-augmented glenoid component.
They compared 40 patients with more than 20 of glenoid retroversion preoperatively (average follow-up, 53 months) vs. a matched cohort of 80 patients with less than 20 of retroversion (average follow-up, 49 months). In all patients, the surgical technique, implant design, and postoperative rehabilitation protocol were identical. Peg components were predominantly used unless the glenoid vault was determined to be narrow based on preoperative imaging. There were 2 keeled glenoid components used in the retroversion group and 5 keeled glenoid components used in the control group. The glenoid was prepared using noncannulated reaming instrumentation with a goal of preparing the glenoid surface to create a minimum of 80% backside concentric support without violation of subchondral bone support. In cases of eccentric wear, the glenoid was reamed to match the backside of the glenoid component, typically preferentially reaming the anterior glenoid and partially correcting glenoid version. Patients were matched based on sex, age, indication, and prosthetic size.
This study should be viewed in light of several other recent articles.
Outcomes of anatomic total shoulder arthroplasty in patients with excessive glenoid retroversion: a case-control study
These authors used a case-controlled study to evaluate the effect of severe preoperative glenoid retroversion on clinical and radiographic total shoulder (TSA) outcomes using a standard non-augmented glenoid component.
They compared 40 patients with more than 20 of glenoid retroversion preoperatively (average follow-up, 53 months) vs. a matched cohort of 80 patients with less than 20 of retroversion (average follow-up, 49 months). In all patients, the surgical technique, implant design, and postoperative rehabilitation protocol were identical. Peg components were predominantly used unless the glenoid vault was determined to be narrow based on preoperative imaging. There were 2 keeled glenoid components used in the retroversion group and 5 keeled glenoid components used in the control group. The glenoid was prepared using noncannulated reaming instrumentation with a goal of preparing the glenoid surface to create a minimum of 80% backside concentric support without violation of subchondral bone support. In cases of eccentric wear, the glenoid was reamed to match the backside of the glenoid component, typically preferentially reaming the anterior glenoid and partially correcting glenoid version. Patients were matched based on sex, age, indication, and prosthetic size.
Preoperatively and postoperatively, both groups demonstrated similar patient reported outcome measures and measured motion.
No significant differences were observed in the postoperative radiographic findings. Postoperative glenoid version was not measured, so the degree of "partial correction" is not known.
The authors concluded that at midterm follow-up, preoperative severe glenoid retroversion does not appear to influence clinical or radiographic outcomes of TSA using a standard glenoid component.
No significant differences were observed in the postoperative radiographic findings. Postoperative glenoid version was not measured, so the degree of "partial correction" is not known.
The authors concluded that at midterm follow-up, preoperative severe glenoid retroversion does not appear to influence clinical or radiographic outcomes of TSA using a standard glenoid component.
Does Postoperative Glenoid Retroversion Affect the 2-Year Clinical and Radiographic Outcomes for Total Shoulder Arthroplasty?
While glenoid retroversion and posterior humeral head decentering are common preoperative features of severely arthritic glenohumeral joints, the relationship of postoperative glenoid component retroversion to the clinical results of total shoulder arthroplasty (TSA) is unclear. Studies have indicated concern for inferior outcomes when glenoid components are inserted in 15° or more retroversion.
In a population of patients undergoing TSA in whom no specific efforts were made to change the version of the glenoid, these authors asked whether at 2 years after surgery patients having glenoid components implanted in 15° 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. They examined the records of 201 TSAs performed using a standard all-polyethylene pegged glenoid component
The mean (± SD) improvement in the SST (6.7 ± 3.6; from 2.6 ± 2.6 to 9.3 ± 2.9) for the retroverted group was not inferior to that for the nonretroverted group (5.8 ± 3.6; from 3.7 ± 2.5 to 9.4 ± 3.0). The percent of maximal possible improvement (%MPI) for the retroverted glenoids (70% ± 31%) was not inferior to that for the nonretroverted glenoids (67% ± 44%). The 2-year SST scores for the retroverted (9.3 ± 2.9) and the nonretroverted glenoid groups (9.4 ± 3.0) were similar (mean difference, 0.2; 95% CI, - 1.1 to 1.4; p = 0.697). 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 (four of 21 [19%] versus six of 50 [12%]; p = 0.436; odds ratio, 1.7; 95% CI, 0.4-6.9), average Lazarus radiolucency scores (0.5 versus 0.7, Mann-Whitney U p value = 0.873; Wilcoxon rank sum test W = 512, p value = 0.836), and the mean percentage of posterior humeral head decentering (3.4% ± 5.5% versus 1.6% ± 6.0%; p = 0.223). The percentage of patients with retroverted glenoids undergoing revision (0 of 21 [0%]) was not inferior to the percentage of those with nonretroverted glenoids (three of 50; [6%]; p = 0.251).
The authors concluded that in this series of TSAs, postoperative glenoid retroversion was not associated with inferior clinical results at 2 years after surgery.
While glenoid retroversion and posterior humeral head decentering are common preoperative features of severely arthritic glenohumeral joints, the relationship of postoperative glenoid component retroversion to the clinical results of total shoulder arthroplasty (TSA) is unclear. Studies have indicated concern for inferior outcomes when glenoid components are inserted in 15° or more retroversion.
In a population of patients undergoing TSA in whom no specific efforts were made to change the version of the glenoid, these authors asked whether at 2 years after surgery patients having glenoid components implanted in 15° 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. They examined the records of 201 TSAs performed using a standard all-polyethylene pegged glenoid component
inserted after conservative glenoid reaming without specific attempt to modify preoperative glenoid version.
Of these, 171 (85%) patients had SST scores preoperatively and between 18 and 36 months after surgery. Ninety-three of these patients had preoperative radiographs in the database and immediate postoperative radiographs and postoperative radiographs taken in a range of 18 to 30 months after surgery. Twenty-two patients had radiographs that were inadequate for measurement at the preoperative, immediate postoperative, or latest followup time so that they could not be included. In comparison to those included in the analysis, the excluded patients did not have substantially different mean age, sex distribution, time of followup, distribution of diagnoses, American Society of Anesthesiologists class, alcohol use, smoking history, BMI, history of prior surgery or preoperative glenoid version. They analyzed the two year outcomes in the remaining 71 TSAs, comparing the 21 in the retroverted group (the glenoid component was implanted in 15° or greater retroversion (mean ± SD, 20.7° ± 5.3°)) with the 50 in the non-retroverted group ( the glenoid component was implanted in less than 15° retroversion (mean ± SD, 5.7° ± 6.9°)).
The mean (± SD) improvement in the SST (6.7 ± 3.6; from 2.6 ± 2.6 to 9.3 ± 2.9) for the retroverted group was not inferior to that for the nonretroverted group (5.8 ± 3.6; from 3.7 ± 2.5 to 9.4 ± 3.0). The percent of maximal possible improvement (%MPI) for the retroverted glenoids (70% ± 31%) was not inferior to that for the nonretroverted glenoids (67% ± 44%). The 2-year SST scores for the retroverted (9.3 ± 2.9) and the nonretroverted glenoid groups (9.4 ± 3.0) were similar (mean difference, 0.2; 95% CI, - 1.1 to 1.4; p = 0.697). 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 (four of 21 [19%] versus six of 50 [12%]; p = 0.436; odds ratio, 1.7; 95% CI, 0.4-6.9), average Lazarus radiolucency scores (0.5 versus 0.7, Mann-Whitney U p value = 0.873; Wilcoxon rank sum test W = 512, p value = 0.836), and the mean percentage of posterior humeral head decentering (3.4% ± 5.5% versus 1.6% ± 6.0%; p = 0.223). The percentage of patients with retroverted glenoids undergoing revision (0 of 21 [0%]) was not inferior to the percentage of those with nonretroverted glenoids (three of 50; [6%]; p = 0.251).
The authors concluded that in this series of TSAs, postoperative glenoid retroversion was not associated with inferior clinical results at 2 years after surgery.
Comment: Glenoid retroversion is a relatively common finding in arthritic glenohumeral joints coming to shoulder arthroplasty. Shoulders with preoperative glenoid retroversion tend to have poorer preoperative shoulder comfort and function, posterior decentering, and glenoid biconcavity, all indicating a more severe form of the disease. There is currently great interest in methods for altering this glenoid retroversion that is commonly found in osteoarthritic glenohumeral joints. Methods used include posterior glenoid bone grafts, reaming the anterior aspect of the glenoid, and posteriorly augmented glenoid components. This study reports the two year results of a more conservative approach in which minimal glenoid bone is removed by reaming and specific attempts to alter glenoid version are not used.
Here is the two year radiographic followup on a 55 year old patient from our practice. Preoperative films show a type B2 genoid with retroversion, biconcavity and posterior humeral subluxation.
Here are the 2 year films of this shoulder after conservative shoulder arthroplasty using a standard glenoid component without attempts to modify glenoid version. The humeral head is centered in the prosthetic glenoid. At two years after surgery the patient was able to perform all 12 functions of the Simple Shoulder Test.
Note that sufficient bone stock remains to perform a revision total or a reverse total shoulder arthroplasty shoulder these procedures become necessary in the future of this young person.
Long term followup of well-characterized patients treated with the different methods for managing glenoid retroversion will be required to define the relative risks, benefits, effectiveness and durability of each of them.
To see a YouTube of our technique for total shoulder arthroplasty, click on this link.
Long term followup of well-characterized patients treated with the different methods for managing glenoid retroversion will be required to define the relative risks, benefits, effectiveness and durability of each of them.
To see a YouTube of our technique for total shoulder arthroplasty, click on this link.
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