Surgical management of the biconcave (B2) glenoid

Treatment of B2 type glenoids with anatomic vs. reverse total shoulder arthroplasty: a retrospective review

Background

Patients with glenohumeral arthritis with Walch B2 glenoid morphology present a challenge for shoulder surgeons. Poor outcomes have been demonstrated in patients with anatomic total shoulder arthroplasty (aTSA) left in retroversion. Reverse total shoulder arthroplasty (rTSA) yields good midterm results. There is a paucity of studies comparing aTSA to rTSA in patients with glenohumeral arthritis and B2 glenoids. The purpose of this study was to compare the results of aTSA vs. rTSA in patients with glenohumeral arthritis with B2 glenoid morphology.

Methods

We performed a retrospective review of patients who underwent total shoulder arthroplasty by a single surgeon. Preoperative computed tomography was used to determine glenoid type based on the modified Walch classification. Patients with B2 glenoid morphology were included in the study. Patients who had evidence of a rotator cuff tear or less than two years of follow-up were excluded. Patients were categorized by procedure type (aTSA vs. rTSA). Preoperative glenoid version, glenoid inclination, and posterior humeral head subluxation were measured using computed tomography. Patient reported outcome measures, active range of motion, and complications requiring revision (instability, rotator cuff insufficiency, infection, component loosening) were recorded. Postoperative glenoid version, glenoid inclination, and evidence of humeral head decentering were evaluated on standard shoulder radiographs. Statistical analysis was performed and results are presented as mean ± standard deviation.

Results

A total of 224 patients were included. One hundred sixty-two patients underwent aTSA and 62 underwent rTSA. The mean length of follow-up was 25.6 ± 1.95 months for the rTSA group and 32.8 ± 2.27 for the aTSA group (P = .002). Patients who underwent rTSA were significantly older (P < .001) and had a significantly higher proportion of females (P = .019). Postoperatively patients in the aTSA group had significantly better external rotation (P < .001) and internal rotation (IR) compared to the rTSA group (P < .001). There were no differences in patient reported outcome measures between the two groups. No patients in the aTSA group had recurrent posterior humeral head subluxation. Eight complications requiring revision occurred, 4 in each group. One patient who underwent aTSA had evidence of glenoid loosening. There was no evidence of glenoid loosening in the rTSA group.

Conclusions

aTSA and rTSA can produce good results in patients with B2 glenoid morphology with low rates of revision with appropriate patient selection. aTSA may result in improved range of motion that may not be clinically relevant.

Current Role of Reverse Total Shoulder Arthroplasty in the Management of Glenohumeral Osteoarthritis

Reverse total shoulder arthroplasty (RSA) was historically reserved for the elderly, low-demand patient with rotator cuff arthropathy (RCA) or as a salvage procedure after failed primary arthroplasty. Surgeon expertise and the advancement of implant design has allowed RSA to now become commonplace not only for RCA but also for glenohumeral osteoarthritis. RSA provides a robust glenoid baseplate fixation, which allows for easier and more reliable bone grafting or augmentation when needed. For patients with severe glenoid bone loss, RSA has been shown to have superior or equivalent patient-reported outcomes and shoulder range of motion when compared with total shoulder arthroplasty.

Pyrolytic carbon head shoulder arthroplasty: CT scan glenoid bone modeling assessment and clinical results at 3-year follow-up

Background

The aim of this study is to report the radiological glenoid modifications and clinical outcomes at 3 years mean follow-up of hemi shoulder arthroplasty (HA) with pyrocarbon (PYC) humeral head. Our hypothesis was that the PYC implants would provide good outcomes without major glenoid erosion. Additionally, we hypothesized that HA-PYC allowed for remodeling of the bone.

Methods

Patients underwent HA with PyC humeral head for treatment of primary or secondary osteoarthritis, excluding post-traumatic cases. All patients had a Constant Score assessed preoperatively and at the last follow-up. Preoperative and postoperative computed tomography scans at the last follow-up were performed to achieve 3-dimensional reconstructions of the scapulae. Deformities of the glenoid surface were analyzed as a distance differential between postoperative and preoperative to investigate potential bone remodeling vs. glenoid erosion. The subluxation index (SLI) was measured.

Results

We included 41 patients implanted with a HA-PYC. Average age at the time of implant was 63.8 (40 to 79 years). All patients were followed for ≥2 years with an average follow-up of 36.3 months (24 to 60 months). Constant Scores increased from 34 at baseline to 80 at the last follow-up points on average (P < .01). Return to work rate was 100% and 96% had resumed their physical activity. Ten (77%) of the 13 patients with posterior head subluxation had normalized their SLI. Furthermore, no significant differences were detected between the individuals having corrected their posterior subluxation and the others (preoperative SLI between 0.45 and 0.55). Glenoid wear is less than 0.6 mm at 3 years mean follow-up, ie, 5 times less than metallic implants. A tendency to recenter the head in the anteroposterior plane was found in type B glenoid, without increased erosion of the glenoid, with very good clinical results. We did not find any difference according to age or glenoid type for clinical and radiological results.

Conclusion

HA-PYCs give, in the short term, excellent clinical results in terms of pain and function. The development of a precise and objective measurement method has made it possible to demonstrate that the glenoid surface is the site of modifications that may be part of bone remodeling or progression of the osteoarthritis disease.

Survivorship of shoulder arthroplasty in young patients with osteoarthritis: an analysis of the Australian Orthopaedic Association National Joint Replacement Registry

BACKGROUND

The treatment of shoulder osteoarthritis in the young patient remains challenging. The higher functional demands and higher expectations of the young patient cohort are often coupled with increased failure and revision rates. Consequently, shoulder surgeons are faced with a unique challenge with implant selection. The aim of this study was to compare the survivorship and reasons for revision of 5 classes of shoulder arthroplasty in patients aged <55 years with a primary diagnosis of osteoarthritis by use of data from a large national arthroplasty registry.

METHODS

The study population included all primary shoulder arthroplasty procedures undertaken for osteoarthritis in patients aged <55 years and reported to the registry between September 1999 and December 2021. Procedures were grouped into the following classes: total shoulder arthroplasty (TSA), hemiarthroplasty resurfacing (HRA), hemiarthroplasty stemmed metallic head (HSMH), hemiarthroplasty stemmed pyrocarbon head (HSPH), and reverse total shoulder arthroplasty (RTSA). The outcome measure was the cumulative percent revision, which was defined using Kaplan-Meier estimates of survivorship to describe the time to the first revision. Hazard ratios (HRs) were calculated from Cox proportional hazards models, adjusting for age and sex, to compare revision rates among groups.

RESULTS

There were 1564 shoulder arthroplasty procedures in patients aged <55 years, of which 361 (23.1%) were HRA, 70 (4.5%) were HSMH, 159 (10.2%) were HSPH, 714 (45.7%) were TSA, and 260 (16.6%) were RTSA. HRA had a higher rate of revision than RTSA after 1 year (HRA = 2.51 (95% CI 1.30, 4.83), P = .005), with no difference prior to that time. In addition, HSMH had a higher rate of revision than RTSA for the entire period (HR, 2.69 [95% confidence interval, 1.28-5.63], P = .008). There was no significant difference in the rate of revision for HSPH and TSA when they were compared with RTSA. Glenoid erosion was the most common cause of revision for HRA (28.6% of revisions) and HSMH (50%). Instability/dislocation was the leading cause of revision for RTSA (41.7%) and HSPH (28.6%), and for TSA, the majority of revisions were for either instability/dislocation (20.6%) or loosening (18.6%).

CONCLUSION

These results should be interpreted within the context of the lack of availability of long-term data on RTSA and HSPH stems. RTSA outperforms all implants regarding revision rates at mid-term follow-up. The high early dislocation rate associated with RTSA, as well as the lack of revision options available to address this, indicates that careful selection of patients and a greater appreciation of anatomic risk factors are needed in the future.

Does improved external rotation following reverse shoulder arthroplasty impact clinical outcomes in patients with rotator cuff pathology and external rotation less than 0°?

BACKGROUND

The purpose of this study was to (1) evaluate whether improved external rotation (ER) in patients with preoperative ER <0° impacts their clinical outcomes following reverse shoulder arthroplasty (RSA) for rotator cuff (RC) pathology and (2) describe the differences in preoperative factors and postoperative outcomes in this patient population. Our hypothesis was that clinical outcomes would not be affected by improvement in ER using a lateralized glenosphere design.

METHODS

We retrospectively reviewed 55 patients with preoperative ER <0° who underwent primary RSA for RC pathology with lateralized glenosphere. Pre- and postoperative physician-reported ER was blindly measured using a videographic review of patients externally rotating their arm at the side. Patients were evaluated using 5 different patient-reported outcome score thresholds, measured at 12 months postoperatively: (1) minimal clinically important difference (MCID) for American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores (ie, ≥20-point increase); (2) MCID for Simple Shoulder Test (SST) scores (≥2.4-point increase); (3) visual analog scale (VAS) for pain score >0; (4) mean ASES score (≥75); and (5) mean SST score (≥6.8), each of which was used to stratify the patients into 2 groups-greater than or equal to vs. less than the threshold. This resulted in 5 different evaluations comparing the 2 groups for any difference in postoperative ER or preoperative factors, including Hamada and Goutallier scores.

RESULTS

Regardless of the measured outcome, there was no difference in either postoperative physician- or patient-reported ER between patients who achieved scores higher or lower than the thresholds. Both Hamada and Goutallier score distributions were not different between groups across all the evaluated outcomes. Patients who achieved the MCID for ASES had worse preoperative VAS pain (7 vs. 4, P = .011) and SST (1 vs. 3, P = .020) scores. Across all outcome thresholds, except MCID for SST, pain reduction (ΔVAS) was significantly more pronounced in patients exceeding the thresholds. Improved forward flexion rather than ER was observed in those who achieved the ASES (160° vs. 80°, P = .020) and SST MCIDs (150° vs. 90°, P = .037). Finally, patients who exceeded the thresholds experienced higher satisfaction rates.

CONCLUSION

Improvement in ER does not appear to impact patient-reported outcome measures, including ASES and SST in patients with preoperative ER <0° undergoing RSA with a lateralized glenosphere. Patients with more severe pain and worse function at baseline experience less postoperative pain and clinically significant improvement in their reported outcomes.

Reverse total shoulder arthroplasty in patients with type B2, B3, and type C glenoids: comparable clinical outcome to patients without compromised glenoid bone stock-a matched pair analysis

BACKGROUND

Primarily posterior bone deficient (dysplastic) (Walch type C) or secondarily eroded (Walch type B2 or B3) glenoids represent a surgical challenge for shoulder arthroplasty. Due to the posteriorly static decentered head, reverse total shoulder arthroplasty (RTSA) is often considered as the treatment of choice. The purpose of this study is to report the clinical and radiographic outcomes, complications and reoperations of RTSA for posteriorly deficient glenoids.

MATERIALS AND METHODS

All patients who underwent RTSA for osteoarthritis secondary to underlying glenoid deficiency (Walch type B2, B3 and C) between 2005 and 2018 (study group), were identified from our institutional shoulder arthroplasty database and gender- and age-matched to a cohort of patients with normal glenoid bone stock (control group). Longitudinal pre- and postoperative clinical [Constant-Murley (CS) score, Subjective Shoulder Value (SSV)] and radiographic outcomes were assessed.

RESULTS

We included 188 patients (94 in each group). The median follow-up was 43 ± 26 (24-144) months in the study group and 59 ± 32 (24-124) months in the control group. The glenoid deficiency was addressed by using glenoid bone reconstruction. The surgical site complication and revision rate of RTSA in patients with bony deficient glenoids were 17% and 7%. Although glenoid loosening was slightly higher in the study group (5 vs. 2), overall no significant differences were found between the study and control groups in satisfaction scores, preoperative and postoperative absolute and relative Constant scores, complication and revision rates, respectively.

CONCLUSION

Reverse total shoulder arthroplasty (RTSA) seems to be a valuable treatment option for patients with primary (dysplasia) or secondary (wear) posterior glenoid deficiency. Although severe glenoid bone loss seems to be a risk factor for glenoid component failure, the overall complication and revision rates as well as clinical and radiographic outcome are comparable to RTSA in patients without compromised glenoid bone stock.

LEVEL OF EVIDENCE

Level III: case-control study.

Biconcave glenoids show 3 differently oriented posterior erosion patterns

BACKGROUND

Posterior glenoid wear remains a challenge in anatomic and reverse total shoulder arthroplasty (rTSA) because of an asymmetric erosion with altered retroversion. The purpose of this study was to assess glenoid morphology and evaluate the influence of acromial orientation in posterior glenoid erosion patterns by using 3-dimensional (3D) models.

MATERIAL AND METHODS

Computed tomographic (CT) shoulder scans from 3 study centers of patients awaiting rTSA between 2017 and 2018 were converted into 3D models and analyzed by 2 observers. Morphology, orientation and greatest depth of erosion, inclination, current retroversion and premorbid retroversion, surface areas of the glenoid, and external acromial orientation and posterior acromial slope were assessed. Measurements were compared between wear patterns, glenoid erosion entities, and genders.

RESULTS

In the complete cohort of 68 patients (63.8 ± 10.0 years; 19 female, 49 male), a mean of 85.9° (±22.2°) was observed for the glenoid erosion orientation. Additionally, a further distinct classification of the glenoid erosion as posterior-central (PC, n = 39), posterior-inferior (PI, n = 12), and posterior-superior (PS, n = 17) wear patterns was possible. These wear patterns significantly (P < .001) distinguished by erosion orientation (PC = 86.9° ± 12.0°, PI = 116.3° ± 10.3°, PS = 62.3° ± 18.9°). The greatest depth of erosion found was 7.3 ± 2.7 mm in PC wear patterns (PC vs. PI: P = .03; PC vs. PS: n.s.; PI vs. PS: n.s.). Overall, the observed erosion divided the glenoid surface into a paleoglenoid proportion of 48% (±11%) and a neoglenoid proportion of 52% (±12%). For the complete cohort, glenoid inclination was 85.4° (±6.6°), premorbid glenoid retroversion was 80.7° (±8.1°), and current glenoid retroversion was 73.4° (±7.4°), with an estimated increase of 6.9° (±6.0°). The mean external acromial orientation was 118.2° (±8.9°), and the mean posterior acromial slope was 107.2° (±9.6°). There were no further significant differences if parameters were compared by wear patterns, entities, and gender.

CONCLUSION

Three significantly differently oriented wear patterns (posterior-superior, posterior-central, and posterior-inferior) were distinguished in shoulders demonstrating posterior wear on axillary imaging. No significant differences between the observed erosion patterns or any relevant correlations were found regarding the orientation of the acromion.

Humeral Head Morphology Influences Outcomes of Arthroscopic Interposition Glenoid Patch Allograft for Glenohumeral Arthritis

Purpose

To determine short- to midterm patient-reported outcomes of arthroscopic soft-tissue interposition arthroplasty using acellular dermal allograft with a minimum follow-up of 1 year and to assess outcomes in patients with and without flattening of the humeral head.

Methods

Patients with a diagnosis of primary glenohumeral arthritis who underwent arthroscopic soft-tissue interposition arthroplasty with an acellular dermal allograft from July 2010 to November 2019 were retrospectively enrolled. Inclusion criteria were a primary diagnosis of glenohumeral arthritis and Outerbridge 4 full-thickness cartilage loss of ≥50% of the glenoid articular surface. Patients underwent arthroscopic debridement, microfracture, and biological arthroscopic soft-tissue interposition arthroplasty with an acellular dermal matrix. Postoperative outcomes included American Shoulder and Elbow Surgeon (ASES) score, Single Assessment Numeric Evaluation (SANE) score, Penn Shoulder Score (PSS), numeric rating scale (NRS) pain score, analgesic use, and conversion to total shoulder arthroplasty (TSA). Results were stratified according to humeral head morphology on preoperative radiographs.

Results

A total of 25 patients were included, with a mean age of 56.0 years (range 19.2 to 74.8) and a mean follow-up of 3.36 years (range 1.03 to 8.98). The mean postoperative ASES score was 64.1 (range 11.7 to 100.0), SANE score was 62% (range 5% to 100%), and PSS was 61.2 (range 10.6 to 97.9). Additionally, 56% of patients rated their shoulder function as improved or much improved, and 36% of patients converted to TSA at a mean of 2.35 years. Patients with and without humeral flattening had similar postoperative ASES scores (P = .44), SANE scores (P = .90), PSS (P = .73), and conversions to TSA (P = .83). Patients with humeral flattening were more likely to have shoulder pain at night (83.3% versus 28.6%, P = .02).

Conclusion

Arthroscopic soft-tissue interposition arthroplasty with an acellular dermal allograft resulted in satisfactory short- to mid-term postoperative outcomes for younger patients with glenohumeral arthritis but demonstrated a TSA conversion rate of 36%. Patients with humeral head flattening also had satisfactory shoulder function but were more likely to experience shoulder pain at night.

Level of Evidence

Level IV, therapeutic case series

Clinical and Radiographic Outcomes of Total Shoulder Arthroplasty With a Nonspherical Humeral Head and Inlay Glenoid in Elite Weight Lifters: A Prospective Case Series

Background:

Weight lifting after total shoulder arthroplasty (TSA) can place significant stresses on implants that could lead to instability, loosening, and increased wear. A TSA system with nonspherical humeral head resurfacing and inlay glenoid—which improves the biomechanics and thus reduces instability, wear, and potential loosening—may be able to tolerate repetitive loads from weight lifting.

Purpose:

To determine clinical and radiographic outcomes after TSA in weight lifters.

Study Design:

Case series; Level of evidence, 4.

Methods:

We prospectively enrolled 16 weight lifters (mean ± SD age, 57.2 ± 7.8 years; 15 male) undergoing primary anatomic TSA (n = 17 shoulders, 1 staged bilateral) with nonspherical humeral head resurfacing and inlay glenoid replacement for glenohumeral osteoarthritis between February 2015 and February 2019. Exclusion criteria were rotator cuff deficiency, revision TSA, post-traumatic arthritis, and inflammatory arthritis. Outcome measures included the rate of return to weight lifting, results of patient-reported outcome measures (Penn Shoulder Score, Kerlan-Jobe Orthopaedic Clinic, and 12-Item Veterans RAND Health Survey), radiographic outcomes, and complication rate.

Results:

Follow-up was obtained on all patients at a mean of 38 months (range, 14-63 months). All patients returned to competitive weight lifting at 15.6 ± 6.9 weeks. Compared to the preoperative weight lifting level, at last follow-up patients reported performance at the following level: lighter weight, 1 (6%); same weight, 8 (50%); heavier weight, 7 (44%). Preoperative eccentric posterior glenoid wear was common (71% Walch B2 classification; 12/17), but posterior humeral subluxation improved at follow-up according to the Walch index (mean, 55.5% preoperative vs 48.5% postoperative; P < .001) and contact point ratio (mean, 63.9% preoperative vs 50.1% postoperative; P < .001). Pre- to postoperative improvements were seen in Penn Shoulder Score (44.3 vs 82.6; P < .001), Kerlan-Jobe Orthopaedic Clinic (50.6 vs 91.1; P < .001), and 12-Item Veterans RAND Health Survey physical component score but not mental component score. No signs of radiographic loosening were detected in follow-up images, nor were there any postoperative instability episodes or revision surgeries.

Conclusion:

There were substantial improvements in shoulder function and a high rate of return to weight lifting after TSA with a nonspherical humeral head resurfacing and inlay glenoid component. Radiographically, the humeral head centralized on the glenoid after surgery, and there was no evidence of component loosening at a mean 38-month follow-up.

Glenoid bony morphology of osteoarthritis prior to shoulder arthroplasty: what the surgeon wants to know and why

Shoulder arthroplasty is performed with increasing frequency, and osteoarthritis is the most common indication for this procedure. However, the glenoid side of the joint is widely recognized as a limiting factor in the long-term durability of shoulder replacement, and osteoarthritis leads to characteristic bony changes at the glenoid which can exacerbate this challenge by reducing the already limited glenoid bone stock, by altering biomechanics, and by interfering with operative exposure. This article reviews the Walch classification system for glenoid morphology. Several typical findings of osteoarthritis at the glenoid are discussed including central bone loss, posterior bone loss, retroversion, biconcavity, inclination, osteophyte formation, subchondral bone quality, and bone density. The three primary types of shoulder arthroplasty are reviewed, along with several techniques for addressing glenoid deformity, including eccentric reaming, bone grafting, and the use of augmented glenoid components. Ultimately, a primary objective at shoulder arthroplasty is to correct glenoid deformity while preserving bone stock, which depends critically on characterizing the glenoid at pre-operative imaging. Understanding the surgical techniques and the implications of glenoid morphology on surgical decision-making enables the radiologist to provide the morphologic information needed by the surgeon.

Ricchetti ET, Khazzam MS, Denard PJ, Dines DM, Bradley Edwards T, Entezari V, Friedman RJ, Garrigues GE, Gillespie RJ, Grawe BM, Green A, Hatzidakis AM, Gabriel Horneff J, Hsu JE, Jawa A, Jin Y, Johnston PS, Jun BJ, Keener JD, Kelly JD, Kwon YW, Miniaci A, Morris BJ, Namdari S, Spencer EE, Strnad G, Williams GR, Iannotti JP. Reliability of the modified Walch classification for advanced glenohumeral osteoarthritis using 3-dimensional computed tomography analysis: a study of the ASES B2 Glenoid Multicenter Research Group

BACKGROUND

Variations in glenoid morphology affect surgical treatment and outcome of advanced glenohumeral osteoarthritis (OA). The purpose of this study was to assess the inter- and intraobserver reliability of the modified Walch classification using 3-dimensional (3D) computed tomography (CT) imaging in a multicenter research group.

METHODS

Deidentified preoperative CTs of patients with primary glenohumeral OA undergoing anatomic or reverse total shoulder arthroplasty (TSA) were reviewed with 3D imaging software by 23 experienced shoulder surgeons across 19 institutions. CTs were separated into 2 groups for review: group 1 (96 cases involving all modified Walch classification categories evaluated by 12 readers) and group 2 (98 cases involving posterior glenoid deformity categories [B2, B3, C1, C2] evaluated by 11 readers other than the first 12). Each case group was reviewed by the same set of readers 4 different times (with and without the glenoid vault model present), blindly and in random order. Inter- and intraobserver reliabilities were calculated to assess agreement (slight, fair, moderate, substantial, almost perfect) within groups and by modified Walch classification categories.

RESULTS

Interobserver reliability showed fair to moderate agreement for both groups. Group 1 had a kappa of 0.43 (95% confidence interval [CI]: 0.38, 0.48) with the glenoid vault model absent and 0.41 (95% CI: 0.37, 0.46) with it present. Group 2 had a kappa of 0.38 (95% CI: 0.33, 0.43) with the glenoid vault model absent and 0.37 (95% CI: 0.32, 0.43) with it present. Intraobserver reliability showed substantial agreement for group 1 with (0.63, range 0.47-0.71) and without (0.61, range 0.52-0.69) the glenoid vault model present. For group 2, intraobserver reliability showed moderate agreement with the glenoid vault model absent (0.51, range 0.30-0.72), which improved to substantial agreement with the glenoid vault model present (0.61, range 0.34-0.87).

DISCUSSION

Inter- and intraobserver reliability of the modified Walch classification were fair to moderate and moderate to substantial, respectively, using standardized 3D CT imaging analysis in a large multicenter study. The findings potentially suggest that cases with a spectrum of posterior glenoid bone loss and/or dysplasia can be harder to distinguish by modified Walch type because of a lack of defined thresholds, and the glenoid vault model may be beneficial in determining Walch type in certain scenarios. The ability to reproducibly separate patients into groups based on preoperative pathology, including Walch type, is important for future studies to accurately evaluate postoperative outcomes in TSA patient cohorts.

The risk of postoperative scapular spine fracture following reverse shoulder arthroplasty is increased with an onlay humeral stem

BACKGROUND

The purpose of this study was to assess the effects of lateralization and distalization on scapular spine fracture (SSF) after reverse shoulder arthroplasty (RSA). The hypothesis was that postoperative distalization would increase the risk of SSF, whereas lateralization would not.

METHODS

A multicenter retrospective review was performed at a minimum of 1 year postoperatively on primary RSAs with 3 different implants, 2 with an inlay design (n = 342) and 1 with an onlay design (n = 84). Functional outcome, range of motion, stem design, and radiographic measurements, including acromiohumeral distance and lateralization, were compared between groups with and without fracture.

RESULTS

The incidence of SSF in the onlay group (11.9%) was significantly higher compared with the inlay group (4.7%; P = .043). Postoperative acromiohumeral distance was approximately 4 mm higher in the SSF group (37.5 mm) compared with the control group (33.7 mm; P = .042), whereas lateralization was similar between the 2 groups (52.8 mm vs. 53.9 mm; P = .362). Higher return to activity (92.1% vs. 71.4%; P < .001) as well as postoperative forward flexion was observed in the group without fracture (135° vs. 120°; P = .009).

CONCLUSION

Increased postoperative distalization is associated with an increased risk of SSF after RSA. An onlay stem resulted in a 10 mm increase in distalization compared with an inlay stem, and a 2.5 times increased risk of SSF. Lateralization, however, does not appear to increase the risk of SSF.

Anatomic Total Shoulder Arthroplasty with All-Polyethylene Glenoid Component for Primary Osteoarthritis with Glenoid Deficiencies

This study evaluated the ability of shoulder arthroplasty using a standard glenoid component to improve patient self-assessed comfort and function and to correct preoperative humeral-head decentering on the face of the glenoid in patients with primary glenohumeral arthritis and type-B2 or B3 glenoids.

Porous metal wedge augments to address glenoid retroversion in anatomic shoulder arthroplasty: midterm update

BACKGROUND

Wedge-shaped porous metal augments were used to address bone deficiency in shoulder arthroplasty as part of a hybrid combination of high-density polyethylene, polymethyl methacrylate bone cement, and porous metal implant. This article presents an ongoing review of the use of the generically designed augments in the shoulder to address glenoid retroversion as part of anatomic total shoulder arthroplasty (aTSA).

MATERIALS

Seventy-five shoulders in 66 patients (23 women and 43 men, aged 42-85 years) with Walch grade B2 or C glenoids underwent porous metal glenoid augment (PMGA) insertion as part of aTSA. Patients underwent preoperative 3-dimensional (3D) templating; based on that planning, patients received either a 15° or 30° PMGA wedge (secured by screws to the native glenoid) to correct excessive glenoid retroversion before a standard glenoid component was implanted using bone cement. Neither patient-specific guides nor navigation were used. Intraoperative glenoid alignment was assessed using a reusable guide that referenced the anterior scapular neck. Patients were prospectively assessed using shoulder functional assessments (Oxford Shoulder Score [OSS], American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], visual analog scale [VAS] pain scores, and forward elevation [FE]) preoperatively; at 3, 6, and 12 months postoperation; and yearly thereafter, with similar radiologic surveillance.

RESULTS

Of the total consecutive series, 49 shoulders had a follow-up of greater than 24 months, with a median follow-up of 48 months (range: 24-87 months). For this cohort, median outcome scores improved for OSS (21 to 44), ASES (24 to 92), VAS (7 to 0), and FE (90° to 140°) from preoperative outcomes to the most recent review, respectively. Four patients died, but no others were lost to follow-up. Apart from 1 infection at 18 months postoperatively and 1 minor peg perforation, there were no complications, hardware failures, implant displacements, significant lucency, or posterior resubluxations. Radiographs showed good incorporation of the wedge augment, with correction of glenoid retroversion from median 22° (13° to 46°) to 4° (17° to anteversion 16°). All but 4 glenoids were corrected to within the target range (less than 10° retroversion), and only 2 glenoid components were implanted outside 15° of neutral glenoid version.

CONCLUSIONS

The porous metal wedge-shaped augments effectively addressed posterior glenoid deficiency as part of aTSA for rotator cuff intact osteoarthritis, producing satisfactory clinical outcomes with no signs of impending future failure.

Comparison of survivorship and performance of a platform shoulder system in anatomic and reverse total shoulder arthroplasty

Background

Contemporary studies note sustained clinical benefit and decreasing complications after reverse total shoulder arthroplasty (RTSA), which warrant a comparison with the standard anatomic total shoulder arthroplasty (ATSA). The purpose of this study is to evaluate and compare differences in midterm survivorship between ATSA and RTSA patients treated with a single platform shoulder prosthesis. Secondary objectives include a comparison of the clinical outcomes and complication profile for each procedure.

Methods

A prospective analysis of all primary ATSA and RTSA performed by 3 surgeons between 2007 and 2012 was conducted. Selection of the ATSA or RTSA implant configuration was determined by the surgeons per their clinical understanding of each individual patient's glenoid morphology, rotator cuff, and patient expectations. All 778 procedures were performed using a single platform shoulder system.

Results

Survivorship for ATSA was similar to that for RTSA at all time points; ATSA at 2 and 8 years was 98.5% and 96.0%, whereas RTSA at 2 and 8 years was 98.7% and 96.0%, respectively ( P= .392). All postoperative range of motion scores for ATSA patients were greater than those for RTSA patients. The overall rate of complications between the ATSA and RTSA groups was similar (6.3% vs. 4.9%, P= .414).

Conclusions

On the basis of this cohort comparison, both ATSA and RTSA demonstrated similar survivorship at 8 years after surgery with multiple surgeons practicing in different countries. Our results demonstrate that the RTSA and ATSA implants have comparable results and can be expected to provide similar implant longevity over the midterm with excellent functional outcomes.

Reverse Shoulder Arthroplasty for B2 Glenoid Deformity

In shoulder osteoarthritis, the B2 glenoid presents challenges in treatment because of the excessive retroversion and posterior deficiency of the glenoid. Correction of retroversion and maintenance of a stable joint line with well-fixed implants are essential for the successful treatment of this deformity with arthroplasty. Reverse shoulder arthroplasty offers several key advantages in achieving this goal, including favorable biomechanics, a well-fixed baseplate, and proven success in other applications. Techniques such as eccentric reaming, bone grafting, and baseplate augmentation allow surgeons to tailor treatment to the patient’s altered anatomy. Eccentric reaming is favored for correction of small defects or mild version anomalies. Current trends favor bone grafting for larger corrections, though augmented components have shown early promise with the potential for expanded use. With overall promising results reported in the literature, reverse shoulder arthroplasty is a useful tool for treating older patients with B2 glenoid deformities.

Anatomic total shoulder arthroplasty with posterior capsular plication versus reverse shoulder arthroplasty in patients with biconcave glenoids: A matched cohort study

PURPOSE

To compare the outcomes of total shoulder arthroplasty (TSA) with posterior capsule plication (PCP) and reverse shoulder arthroplasty (RSA) in patients with primary osteoarthritis, posterior subluxation, and bone loss (Walch B2).

PATIENTS AND METHODS

All shoulders undergoing anatomic TSA with PCP were retrospectively identified (group 1, G1) and compared to shoulders undergoing RSA (group 2, G2) for Walch B2 osteoarthritis. There were 15 patients in G1 (mean (SD) age and follow-up of 70.5 (7.5) years and 42.8 (18.4) months, respectively) and 16 patients in G2 (mean (SD) age and follow-up of 72.6 (5.4) years and 35.1 (14.2) months, respectively).

RESULTS

Both groups had substantial improvements in pain and function. In G1, results were excellent in 80% and satisfactory in 20%, compared to 81% and 6% in G2, respectively ( p = 0.2). The mean (SD) American Shoulder and Elbow Surgeons score was 91.2 (6.7) and 80.3 (14.3) in G1 and G2, respectively ( p = 0.08). The mean Simple Shoulder Test score was 10.6 in G1 and 8.5 in G2 ( p = 0.01). There were no reoperations in either group, but G1 had seven postoperative complications.

CONCLUSIONS

The outcomes of TSA with PCP are comparable to RSA in patients with osteoarthritis and biconcave glenoids. However, TSA leads to more complications while RSA leads to lower functional outcomes.

Eccentric Reaming for B2 Glenoids: History, Preoperative Planning, Surgical Technique, and Outcome

Background

The biconcave (B2) glenoid is characterized by preservation of the anterior portion of the native glenoid with asymmetric wear of the posterior glenoid. Surgical options for glenoid correction have evolved. The goal of shoulder arthroplasty is to place the implants in such a manner to return the humeral head to a centered position and restore the joint line to a neutral position. There is no current consensus on method of treatment and correction.

Methods

The current and historical literature on total shoulder arthroplasty was used to examine technique viability.

Results

Asymmetric remaining can be used to address up to 15° of version correction without compromise of cortical bone. It is important to have the proper presurgical planning, to understand the limitations of correction, and to have other options available to treat the biconcave glenoid.

Imaging of the B2 Glenoid: An Assessment of Glenoid Wear

Background

Glenohumeral osteoarthritis (OA) carries a spectrum of morphology and wear patterns of the glenoid surface exemplified by complex patterns such as glenoid biconcavity and acquired retroversion seen in the B2 glenoid. Multiple imaging methods are available for evaluation of the complex glenoid structure seen in B2 glenoids. The purpose of this article is to review imaging assessment of the type B2 glenoid.

Methods

The current literature on imaging of the B2 glenoid was reviewed to describe the unique anatomy of this OA variant and how to appropriately assess its characteristics.

Results

Plain radiographs, magnetic resonance imaging, and standard 2-dimensional computed tomography (CT) have all shown acceptable assessments of arthritic glenoids but lack the detailed and highly accurate evaluation of bone loss and retroversion seen with 3-dimensional CT.

Conclusion

Accurate preoperative identification of complex B2 pathology on imaging remains essential in planning and achieving precise implant placement at the time of shoulder arthroplasty.

Quantitative Measurement of Osseous Pathology in Advanced Glenohumeral Osteoarthritis

BACKGROUND

Osteoarthritis of the glenohumeral joint has typical patterns of deformity as described by Walch et al. However, more severe glenoid pathology may be difficult to classify. The purpose of this study was to use 3-dimensional computed tomography (3-D CT) imaging analysis to define common pathologic subtypes that can be differentiated from the current Walch classification.

METHODS

We performed quantitative measurements of premorbid and pathologic anatomy using preoperative 3-D CT scans from 155 cases of advanced glenohumeral osteoarthritis that underwent anatomic or reverse total shoulder arthroplasty. We defined premorbid glenohumeral anatomy on the basis of previously validated methods using 3-D glenoid vault and humeral best-fit circle models including the premorbid glenoid version, joint-line medialization, and humeral-glenoid alignment (HGA). We determined the anatomic features that differentiate new glenoid morphologic subtypes from the existing Walch classification both qualitatively and quantitatively.

RESULTS

We defined 2 new glenoid subtypes (B3 and C2) for which the glenoid pathology and humeral alignment were not defined in the original Walch classification. The B3 glenoid has high pathologic retroversion, normal premorbid version, and acquired central and posterior bone loss that, on average, is greater than that of the B2 glenoid. The C2 glenoid is dysplastic with high pathologic retroversion, high premorbid version, and acquired posterior bone loss, giving it the appearance of a biconcave glenoid with posterior translation of the humeral head. This C2 glenoid can be confused with the B2 glenoid.

CONCLUSIONS

The B3 and C2 patterns have qualitative and quantitative differences that may result in different clinical outcomes than classic B2 or C types; therefore, our findings suggest that these new subtypes should be included in a new or modified classification system.

Plication of the posterior capsule for intraoperative posterior instability during anatomic total shoulder arthroplasty

BACKGROUND

Restoration of soft tissue balance for intraoperative posterior instability during anatomic total shoulder arthroplasty (TSA) is particularly difficult. The effectiveness of posterior capsular plication (PCP) in restoring soft tissue balance is largely unknown. The purpose of this study was to report the outcomes, complications, and reoperations of primary TSA in which a PCP was performed to correct excessive intraoperative posterior subluxation.

METHODS

Thirty-eight shoulders (37 patients) underwent PCP for intraoperative posterior instability during anatomic TSA. The mean (standard deviation) age was 68 (10) years, and the median (range) clinical and radiographic follow-up periods were 60 (10-154) and 48 (1.5-154) months, respectively. A retrospective chart review was conducted to obtain clinical and radiographic data.

RESULTS

TSA resulted in significant improvements in pain and range of motion. The mean (standard deviation) Simple Shoulder Test and American Shoulder and Elbow Surgeons scores were 9.4 (2.7) and 81.1 (19.8), respectively. PCP resulted in restoration of soft tissue balance in 27 shoulders (71%). The remaining 11 shoulders had evidence of posterior subluxation, including posterior dislocation in 2 shoulders. Revision surgery was performed in only 3 shoulders (7.9%), all for instability. However, there was a high rate of radiographic glenoid component loosening (12 shoulders, 32%). Overall results were excellent in 24 (63.2%), satisfactory in 10 (26.3%), and unsatisfactory in 4 (10.5%) shoulders. Recurrence of posterior subluxation was associated with worse motion and strength as well as with a higher rate of glenoid loosening.

CONCLUSIONS

PCP seems to correct excessive intraoperative posterior subluxation in approximately two-thirds of the shoulders undergoing anatomic TSA. However, posterior subluxation does recur in the remaining third, and the overall rate of radiographic glenoid loosening is of concern.

Magnetic resonance imaging is comparable to computed tomography for determination of glenoid version but does not accurately distinguish between Walch B2 and C classifications

BACKGROUND

Computed tomography (CT) scan is the standard for the preoperative assessment of glenoid version and morphology before total shoulder arthroplasty. However, the capacity of magnetic resonance imaging (MRI) to visualize bone morphology has improved with advancing technology. The purpose of this study was to compare the accuracy of MRI to CT for assessment of glenoid version and Walch classification.

METHODS

Three fellowship-trained shoulder surgeons assessed glenoid version and Walch classification of 30 patients with primary shoulder osteoarthritis who received both CT and MRI scans before total shoulder arthroplasty. Version measurements, Walch classification, and observer agreement were compared.

RESULTS

Mean glenoid version was -15.5° and -18.6° by CT and MRI, respectively (P = .17). Interobserver reliability coefficients were good for both imaging modalities (CT, 0.73; MRI, 0.62). Intraobserver coefficients were good to excellent for CT (range, 0.76-0.87) and good for MRI (range, 0.75-0.79). For Walch classification, interobserver reliability for both modalities was merely fair, whereas intraobserver reliability was moderate to good. Although identification of type A1, A2, and B1 was nearly identical between CT and MRI, there was observer disagreement on type B2 (P = .001) and C glenoids (P = .03). Specifically, MRI underidentified type B2 and overidentified type C compared with CT.

CONCLUSIONS

MRI is largely comparable to CT scan for evaluation of the glenoid, with similar measurements of version and identification of less extreme Walch glenoids. However, MRI is less accurate at distinguishing between type B2 and C glenoids.