Recentering the humeral head for glenoid deficiency in total shoulder arthroplasty

Midterm radiographic outcomes of anatomic total shoulder arthroplasty in biplanar glenoid deformities

BACKGROUND

Optimal management of retroversion in anatomic total shoulder arthroplasty (aTSA) remains controversial, and limited attention has been directed to the impact of glenoid inclination. Prior biomechanical study suggests that residual glenoid inclination generates shear stresses that may lead to early glenoid loosening. Combined biplanar glenoid deformities may complicate anatomic glenoid reconstruction and affect outcomes. The goal of this matched-cohort analysis was to assess the relationship between biplanar deformities and midterm radiographic loosening in aTSA.

METHODS

The study cohort was identified via an institutional repository of 337 preoperative CT scans from 2010 to 2017. Glenoid retroversion, inclination, and humeral head subluxation were assessed via 3D-planning software. Patients with retroversion ≥20° and inclination ≥10° who underwent aTSA with eccentric reaming and nonaugmented components were matched by age, sex, retroversion, and Walch classification to patients with retroversion ≥20° only. Primary outcome was glenoid component Lazarus radiolucency score.

RESULTS

Twenty-eight study subjects were matched to 28 controls with retroversion only. No difference in age (61.3 vs. 63.6 years, P = .26), sex (19 [68%] vs. 19 [68%] male, P > .99), or follow-up (6.1 vs. 6.4 years, P = .59). Biplanar deformities had greater inclination (14.5° vs. 5.3°, P < .001), retroversion (30.0° vs. 25.6°, P = .01), and humeral subluxation (86.3% vs. 82.1%, P = .03). Biplanar patients had greater postoperative implant superior inclination (5.9° [4.6°] vs. 3.0° [3.6°], P = .01) but similar rate of complete seating 24 [86%] vs. 24 [86%] P > .99). At final follow-up, biplanar subjects had higher Lazarus radiolucent scores (2.4 [1.7] vs. 1.6 [1.1], P = .03) and a higher proportion of patients with glenoid radiolucency (19 [68%] vs. 11 [39%], P = .03). No difference in complete component seating (86% vs. 86%, P = .47) or initial radiolucency grade (0.21 vs. 0.29, P = .55) on immediate postop radiographs. Biplanar patients demonstrated a greater amount of posterior subluxation at immediate postoperative (3.5% [1.3%] vs. 1.8% [0.6%]; P = .03) and final follow-up (7.6% [2.8%] vs. 4.0% [1.8%]; P = .04). At final radiographic follow-up, biplanar subjects had higher Lazarus radiolucent scores (2.4 [1.7] vs. 1.6 [1.1], P = .03; ICC = 0.82). Bivariate regression analysis demonstrated that biplanar deformity was the only significant predictor (OR 3.3, P = .04) of glenoid radiolucency.

DISCUSSION

Biplanar glenoid deformity resulted in time-zero glenoid implant superior inclination and increased midterm radiographic loosening and posterior subluxation. Attention to glenoid inclination is important for successful anatomic glenoid reconstruction. Future research is warranted to understand the long-term implications of these findings and impact of using augmented implants or reverse shoulder arthroplasty to manage biplanar deformities.

Structural bone grafting for glenoid bone loss in primary anatomic total shoulder arthroplasty: a case series and technique report

Background

Posterior glenoid bone loss in glenohumeral osteoarthritis poses significant challenges in shoulder arthroplasty. Anatomic total shoulder arthroplasty (TSA) with a humeral head autograft to address the glenoid bone deficiency is an option for these difficult cases. Variable results with this procedure are reported in the literature. This article describes the surgical technique of posterior glenoid bone grafting in TSA using a glenoid implant with hybrid fixation and a series of reported patient functional and radiographic outcomes.

Methods

A retrospective chart review of cases from 2015 to 2020 by a single surgeon revealed 10 patients who underwent primary TSA with hybrid glenoid component and posterior glenoid bone grafting. Preoperative and postoperative radiographs were assessed for glenoid inclination, glenoid version, acromiohumeral distance, humeral stem status, and glenoid implant status. Functional outcomes were evaluated by range of motion, strength, and patient-reported clinical outcomes (pain and function on a visual analog scale, Disabilities of the Arm, Shoulder, and Hand score, Single Assessment Numeric Evaluation, American Shoulder and Elbow Surgeons score). Complications and reoperations were also evaluated.

Results

Average follow-up was 31.4 months, active forward flexion and external rotation improved on average from 105° to 150° and 20° to 60°, respectively (P < .001) and average abduction improved from 100° to 140° (P < .002). At an average of 26.7 months, patients reported assessments (visual analog scale pain and function, Disabilities of the Arm, Shoulder, and Hand score, Single Assessment Numeric Evaluation, American Shoulder and Elbow Surgeons scores) reveal significant (P < .05) improvement in pain and functional outcomes. Radiographically, at 23.0 ± 20.1 months, all patients demonstrated a well-fixed humeral and glenoid component without evidence of lucent lines. The bone graft used in each patient was well unionized and no radiographic complications were reported. No patients underwent revision surgery, and there was one clinical complication reported, which consisted of a suspected rotator cuff injury at follow-up.

Conclusion

Hybrid fixation with structural glenoid bone grafting in TSA resulted in excellent outcomes with no evidence of graft or component failure on follow-up radiographs and significantly reduced pain, improved functional scores, and improved active range of motion.

Total shoulder arthroplasty for primary glenohumeral osteoarthritis: does posterior humeral subluxation persist after correction of the glenoid version at 5 years minimum?

BACKGROUND

Primary glenohumeral osteoarthritis is associated with both excessive posterior humeral subluxation (PHS) and excessive glenoid retroversion in 40% of cases. These morphometric abnormalities are a particular issue because they may be responsible for a deterioration in long-term clinical and radiologic outcomes. The aim of this study was to perform a computed tomographic (CT) analysis of patients who underwent total shoulder arthroplasty (TSA) for primary osteoarthritis (OA) with B2-, B3-, or C-type glenoids in whom an attempt was made to correct for excessive glenoid retroversion and excessive posterior humeral subluxation intraoperatively.

MATERIAL

We performed a retrospective, single-center study including 62 TSA patients with a preoperative PHS of the glenohumeral joint (31 men, 31 women, 70 ± 9 years) between January 2000 and January 2014. Glenoids were classified as B2 (32 cases), B3 (13 cases), or C (17 cases). Glenoid retroversion was corrected by anterior asymmetric reaming. Patients were reviewed for clinical and CT scan assessment with a mean follow-up of 8.3 years (minimum 5 years). At final follow-up, the CT images were reconstructed in the scapular plane. A PHS index >65% defined persistence.

RESULTS

The revision-free rate was estimated at 93%. Correlation between PHS and retroversion was moderate preoperatively (ρ = 0.58) and strong at final follow-up (ρ = 0.73). Postoperative CT scans on average showed a surgical correction of PHS compared to preoperatively (79% vs. 65% respectively, P < .05) and retroversion (20° vs. 10° respectively, P < .05). At final follow-up, 25 of 62 patients had a persistence in the 2-dimensional (2D) model and 41 of 62 in the corrected 2D model. Persistence of PHS had no influence on clinical outcomes but did demonstrate a significantly higher glenoid loosening rate (20% vs. 59%, P < .05).

CONCLUSION

Correlation between PHS and retroversion was moderate preoperatively and strengthened at long-term follow-up. Anterior asymmetric reaming allowed for a surgical improvement of both PHS and retroversion, but it was not sufficient to maintain a correction over time. Glenoid loosening was more frequent in case of PHS persistence but seemingly without clinical relevance.

Return to Sports Activity After Reverse Total Shoulder Arthroplasty

Background

There are little published data on return to sports (RTS) after reverse total shoulder arthroplasty (RTSA).

Purpose

To (1) determine the rate and timing of RTS after RTSA in an Asian population, (2) analyze predictive factors for RTS, and (3) determine the relationship between RTS after RTSA and clinical/radiological outcomes.

Study Design

Case-control study; Level of evidence, 3.

Methods

A retrospective review was performed on consecutive patients with diagnosis of irreparable rotator cuff tear (RCT), cuff tear arthropathy (CTA), or degenerative osteoarthritis who underwent RTSA between May 2017 and May 2020. Included were patients who played sports preoperatively in ≤3 years and had ≥2-year follow-up. Patients were divided into 2 groups based on responses to a telephone survey about RTS after RTSA: those who returned to sports (group A) and those who did not (group B). Patient characteristics, pre- and postoperative clinical features and functional scores, and radiologic outcomes (acromial fracture, scapular notching, heterotopic ossification, and loosening of humeral and glenoid component) were compared between the groups.

Results

Of 59 eligible patients, 44 patients (28 in group A, 16 in group B) were included. The RTS rate after RTSA was 63.6%, and the mean RTS time was 9.1 months (range, 3-36 months). There was a significant group difference in body mass index (BMI) (group A, 24.3 ± 2.1; group B, 27.1 ± 4.4; P = .01) and preoperative diagnosis (CTA/irreparable RCT/degenerative osteoarthritis diagnoses: group A, 13/12/3; group B, 3/6/7; P = .03). Patients in group A showed significantly higher forward flexion (P = .03) and higher Simple Shoulder Test score (P = .02) than group B at final clinical follow-up. No significant difference in radiological outcomes was found between the groups.

Conclusion

Patients with a low BMI and those diagnosed with CTA or irreparable RCT were found to have better RTS rates after undergoing RTSA, and forward flexion and Simple Shoulder Test scores at final follow-up were significantly higher in the RTS group, with no significant differences in complications.

The role of the anterior shoulder joint capsule in primary glenohumeral osteoarthritis

The pathogenesis of primary glenohumeral arthritis (GHOA) is mediated by a complex interaction between osseous anatomy and the surrounding soft tissues. Recently, there has been growing interest in characterizing the association between the anterior shoulder joint capsule and primary GHOA because of the potential for targeted treatment interventions. Emerging evidence has shown substantial synovitis, fibrosis, and mixed inflammatory cell infiltrate in the anterior capsule of osteoarthritic shoulders. In addition, increased thickening of the anterior shoulder joint capsule has been associated with greater posterior glenoid wear and humeral head subluxation. While these findings suggest that anterior capsular disease may play a causative role in the etiology and progression of eccentric GHOA, further studies are needed to support this association. The purpose of this article is to review the pathogenesis of primary GHOA, contextualize current hypotheses regarding the role of the anterior capsule in the disease process, and provide directions for future research.

Quantitative statistical shape model-based analysis of humeral head migration, Part 2: Shoulder osteoarthritis

We wanted to investigate the quantitative characteristics of humeral head migration (HHM) in shoulder osteoarthritis (OA) and their possible associations with scapular morphology. We quantified CT-scan-based-HHM in 122 patients with a combination of automated 3D scapulohumeral migration (=HHM with respect to the scapula) and glenohumeral migration (=HHM with respect to the glenoid) measurements. We divided OA patients in Group 1 (without HHM), Group 2a (anterior HHM) and Group 2b (posterior HHM). We reconstructed and measured the prearthropathy scapular anatomy with a statistical shape model technique. HHM primarily occurs in the axial plane in shoulder OA. We found "not-perfect" correlation between subluxation distance AP and scapulohumeral migration values (r_s  = 0.8, p < 0.001). Group 2b patients had a more expressed prearthropathy glenoid retroversion (13° vs. 7°, p < 0.001) and posterior glenoid translation (4 mm vs. 6 mm, p = 0.003) in comparison to Group 1. Binary logistic regression analysis indicated prearthropathy glenoid version as a significant predictor of HHM (χ² = 27, p < 0.001). Multivariate regression analysis showed that the pathologic version could explain 56% of subluxation distance-AP variance and 75% of the scapulohumeral migration variance (all p < 0.001). Herewith, every degree increase in pathologic glenoid retroversion was associated with an increase of 1% subluxation distance-AP, and scapulohumeral migration. The occurrence of posterior HHM is associated with prearthropathy glenoid retroversion and more posterior glenoid translation. The reported regression values of HHM in the function of the pathologic glenoid version could form a basis toward a more patient-specific correction of HHM.

Considerations for Shoulder Arthroplasty Implant Selection in Primary Glenohumeral Arthritis With Posterior Glenoid Deformity

Glenoid deformity has an important effect on outcomes and complication rates after shoulder arthroplasty for primary glenohumeral arthritis. The B2/B3 glenoid has particularly been associated with a poorer outcome with shoulder arthroplasty compared with other glenoid types. One of the primary challenges is striking a balance between deformity correction and joint line preservation. Recently, there has been a proliferation of both anatomic and reverse implants that may be used to address glenoid deformity. The purpose of this review was to provide an evidence-based approach for addressing glenoid deformity associated with primary glenohumeral arthritis.

The association between anterior shoulder joint capsule thickening and glenoid deformity in primary glenohumeral osteoarthritis

BACKGROUND

Anterior shoulder joint capsule thickening is typically present in osteoarthritic shoulders, but its association with specific patterns of glenoid wear is incompletely understood. We sought to determine the relationship between anterior capsular thickening and glenoid deformity in primary glenohumeral osteoarthritis.

METHODS

We retrospectively identified 134 consecutive osteoarthritic shoulders with magnetic resonance imaging and computed tomography scans performed. Axial fat-suppressed magnetic resonance imaging slices were used to quantify the anterior capsular thickness in millimeters, measured at its thickest point below the subscapularis muscle. Computed tomography scans were used to classify glenoid deformity according to the Walch classification, and an automated 3-dimensional software program provided values for glenoid retroversion and humeral head subluxation. Multinomial and linear regression models were used to characterize the association of anterior capsular thickening with Walch glenoid type, glenoid retroversion, and posterior humeral head subluxation while controlling for patient age and sex.

RESULTS

The anterior capsule was thickest in glenoid types B2 (5.5 mm, 95% confidence interval [CI]: 5.0-6.0) and B3 (6.1 mm, 95% CI: 5.6-6.6) and thinnest in A1 (3.7 mm, 95% CI: 3.3-4.2; P < .001). Adjusted for age and sex, glenoid types B2 (odds ratio: 4.4, 95% CI: 2.3-8.4, P < .001) and B3 (odds ratio: 5.4, 95% CI: 2.8-10.4, P < .001) showed the strongest association with increased anterior capsule thickness, compared to glenoid type A1. Increased capsular thickness correlated with greater glenoid retroversion (r = 0.57; P < .001) and posterior humeral head subluxation (r = 0.50; P < .001). In multivariable analysis, for every 1-mm increase in anterior capsular thickening, there was an adjusted mean increase of 3.2° (95% CI: 2.4-4.1) in glenoid retroversion and a 3.8% (95% CI: 2.7-5.0) increase in posterior humeral head subluxation.

CONCLUSIONS

Increased thickening of the anterior shoulder capsule is associated with greater posterior glenoid wear and humeral head subluxation. Additional research should determine whether anterior capsular disease plays a causative role in the etiology or progression of eccentric glenohumeral osteoarthritis.

Glenoid retroversion does not impact clinical outcomes or implant survivorship after total shoulder arthroplasty with minimal, noncorrective reaming

Hypothesis

Both clinical outcomes and early rates of failure will not be associated with glenoid retroversion.

Methods

All patients who underwent an anatomic total shoulder arthroplasty with minimal, noncorrective reaming between 2006 and 2016 with minimum 2-year follow-up were reviewed. Measurements for retroversion, inclination, and posterior subluxation were obtained from magnetic resonance imaging or computerized tomography. A regression analysis was performed to assess the association between retroversion, inclination and subluxation, and their effect on patient reported outcomes (PROs). Clinical failures and complications were reported.

Results

One hundred fifty-one anatomic total shoulder arthroplasties (90% follow-up) with a mean follow-up of 4.6 years (range, 2-12 years) were assessed. The mean preoperative retroversion was 15.6° (range, 0.2-42.1), the mean posterior subluxation was 15.1% (range, -3.6 to 44.1%), and the mean glenoid inclination was 13.9° (range, -11.3 to 44.3). All median outcome scores improved significantly from pre- to post-operatively (P < .001). The median satisfaction was 10/10 (1st quartile = 7 and 3rd quartile = 10). Linear regression analysis found no significant association between retroversion and any postoperative PRO. A total of 5 (3.3%) failures occurred due to glenoid implant loosening (3 patients) and Cutibacterium acnes infection (2 patients) with no association between failure causation and increased retroversion or inclination. No correlation could be found between the Walch classification and postoperative PROs.

Conclusion

Anatomic total shoulder replacement with minimal and noncorrective glenoid reaming demonstrates reliable increases in patient satisfaction and clinical outcomes at a mean of 4.6-year follow-up in patients with up to 40° of native retroversion. Higher values of retroversion were not associated with early deterioration of clinical outcomes, revisions, or failures. Long-term studies are needed to see if survivorship and outcomes hold up over time.

Shoulder structure and function: The impact of osteoarthritis and rehabilitation strategies

STUDY DESIGN

Invited review.

BACKGROUND

Shoulder osteoarthritis can result in significant functional deficits. To improve diagnosis and treatment, we must better understand the impact of osteoarthritis on shoulder biomechanics and the known mechanical benefits of currently available treatments.

PURPOSE

The purpose of this paper is to present up-to-date data on the effects of osteoarthritis and rehabilitation on the biomechanical parameters contributing to shoulder function. With this goal, we also reviewed the anatomy and the ranges of motion of the shoulder.

METHODS

A search of electronic databases was conducted. All study designs were included to inform this qualitative, narrative literature review.

RESULTS

This review describes the biomechanics of the shoulder, the impact of osteoarthritis on shoulder function, and the treatment of shoulder osteoarthritis with an emphasis on rehabilitation.

CONCLUSIONS

The shoulder is important for the completion of activities of daily living, and osteoarthritis of the shoulder can significantly reduce shoulder motion and arm function. Although shoulder rehabilitation is an integral treatment modality to improve pain and function in shoulder osteoarthritis, few high-quality studies have investigated the effects and benefits of shoulder physical and occupational therapies. To advance the fields of therapy and rehabilitation, future studies investigating the effects of therapy intensity, therapy duration, and the relative benefits of therapy subtypes on shoulder biomechanics and function are necessary.

Glenohumeral osteoarthritis with intact rotator cuff treated with reverse shoulder arthroplasty: a systematic review

BACKGROUND

Although reverse shoulder arthroplasty (RSA) has shown satisfactory outcomes in rotator cuff-deficient shoulders, its performance in shoulders with an intact rotator cuff has not been fully elucidated. Shoulder osteoarthritis can present with alterations in glenoid morphology, which have contributed to inconsistent outcomes in anatomic shoulder replacement. The glenoid component is responsible for a predominance of these arthroplasty complications. Given these glenoid-related difficulties, RSA may provide a more favorable option. We aimed to summarize the current literature on rotator cuff intact osteoarthritis treated with primary RSA and to determine whether morphologic changes in the glenoid led to inferior outcomes.

METHODS

A literature search was performed using an inclusion criterion of primary RSA for osteoarthritis with an intact rotator cuff. The Modified Coleman Methodology Score was calculated to analyze reporting quality. Following appropriate exclusions, of the 1002 studies identified by the databases, 13 were selected.

RESULTS

Postoperative improvement in weighted means for Constant scores reached statistical significance (P = .02). The mean rate of major complications was 3.8%. A subset of 8 studies was created that detailed the following descriptions of altered glenoid morphology: "static posterior instability," "severe posterior subluxation," "posterior glenoid wear >20°," "significant posterior glenoid bone loss," "biconcave glenoid," "B2 glenoid," and "B/C glenoid." Within this subset, the mean complication rate was 4.7%, with 4 of the 7 studies having a rate ≤ 3%, and improvements in the Constant score (P = .002) and external rotation (P = .02) reached statistical significance.

DISCUSSION

RSA as treatment for osteoarthritis with an intact rotator cuff provides optimal outcomes with low complication rates across a short term of follow up. Preoperative considerations for using reverse arthroplasty in the treatment of osteoarthritis with an intact rotator cuff include glenoid retroversion, posterior humeral subluxation, and glenoid bone loss. The attributes of reverse arthroplasty that contribute to favorable outcomes in arthritic shoulders include its semiconstrained design and robust glenoid fixation. Soft-tissue imbalances as a consequence of pathologic glenoid morphology and chronic humeral subluxation can be mitigated with the RSA semiconstrained design. Glenoid bone loss can be effectively managed with RSA's robust glenoid fixation, with and without the use of bone graft. The capability to lateralize the joint center of rotation may be valuable when faced with a medialized glenoid wear pattern. The current findings suggest that reverse arthroplasty can achieve highly favorable outcomes for glenohumeral osteoarthritis with an intact rotator cuff.

Anatomic vs. reverse shoulder arthroplasty for the treatment of Walch B2 glenoid morphology: a systematic review and meta-analysis

Background

Walch B2 glenoid morphology with glenohumeral osteoarthritis is a difficult degenerative pattern to manage for shoulder surgeons. Anatomic total shoulder arthroplasty (TSA) in combination with eccentric reaming or bone grafting are the traditional methods of treatment. Newer approaches such as TSA with posteriorly augmented glenoid components and reverse shoulder arthroplasty (RSA) may offer better stability for the posteriorly subluxated biconcave B2 wear pattern. The aim of this systematic review is to compare mid-term surgical and functional outcomes of Walch B2 glenoids without significant rotator cuff pathology treated with TSA and RSA.

Methods

The review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines by searching the MEDLINE (PubMed) and Embase (Elsevier) databases. Inclusion criteria were clinical studies that evaluated the outcomes and complications of TSA or RSA in the setting of B2 glenoid morphology without significant rotator cuff pathology. Data relevant to TSA and RSA surgical outcomes were extracted and compiled, and outcomes were compared. A meta-analysis of proportions of complication and revision rates among TSA and RSA groups was performed.

Results

Overall, 16 articles were included with 414 TSAs and 78 RSAs. The average follow-up duration was 54.1 ± 14.8 months for patients undergoing TSA and 44.8 ± 10.1 months for patients undergoing RSA. The TSA group was further subdivided based on the use of eccentric reaming (135 TSAs), an augmented glenoid component (84 TSAs), or bone grafting (11 TSAs) or was unspecified (184 TSAs). Overall, patients undergoing TSA and RSA demonstrated mean improvements of 50.1 ± 8.5° and 64.7 ± 5.2° in active flexion, 58.5 ± 10.3° and 68.9 ± not reported° in active abduction, and 31.3 ± 5.7° and 29.0 ± 10.2° in active external rotation, respectively. In regard to functional outcome scores, patients undergoing TSA and RSA showed mean Constant score improvements of 38.8 ± 5.3 and 46.6 ± 3.1 points and American Shoulder and Elbow Surgeons score improvements of 48.2 ± 1.0 and 49.2 ± 25.3 points, respectively. Results of the meta-analysis with mid-term follow-up data demonstrated pooled complication rates of 9% (95% confidence interval [CI], 1%-22%) for TSA and 6% (95% CI, 0%-28%) for RSA and pooled revision rates of 2% (95% CI, 0%-8%) for TSA and 1% (95% CI, 0%-15%) for RSA.

Conclusion

In the setting of Walch B2 glenoid morphology, TSA with eccentric reaming or an augmented component yields comparable outcomes to RSA. Based on the patient's age, activity level, and expectations, both TSA and RSA can be considered a reasonable option to treat Walch B2 glenoid morphology.

Subluxation in the Arthritic Shoulder

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The term "subluxation" means partial separation of the joint surfaces. In the arthritic shoulder, "arthritic glenohumeral subluxation" refers to displacement of the humeral head on the surface of the glenoid.

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The degree of arthritic glenohumeral subluxation can be measured using radiography with standardized axillary views or computed tomography (CT).

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Shoulders with a type-B1 or B2 glenoid may show more posterior subluxation on an axillary radiograph that is made with the arm in an elevated position than on a CT scan that is made with the arm at the side.

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The degree of arthritic glenohumeral subluxation is not closely related to glenoid retroversion.

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The position of the humeral head with respect to the plane of the scapula is related to glenoid retroversion and is not a measure of glenohumeral subluxation.

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Studies measuring glenohumeral subluxation before and after arthroplasty should clarify its importance to the clinical outcomes of shoulder reconstruction.

Relationship Between Glenoid Component Shift and Osteolysis After Anatomic Total Shoulder Arthroplasty: Three-Dimensional Computed Tomography Analysis

BACKGROUND

The purpose of this study was to evaluate glenoid component position and radiolucency following anatomic total shoulder arthroplasty (TSA) using sequential 3-dimensional computed tomography (3D CT) analysis.

METHODS

In a series of 152 patients (42 Walch A1, 16 A2, 7 B1, 49 B2, 29 B3, 3 C1, 3 C2, and 3 D glenoids) undergoing anatomic TSA with a polyethylene glenoid component, sequential 3D CT analysis was performed preoperatively (CT1), early postoperatively (CT2), and at a minimum 2-year follow-up (CT3). Glenoid component shift was defined as a change in component version or inclination of ≥3° from CT2 to CT3. Glenoid component central anchor peg osteolysis (CPO) was assessed at CT3. Factors associated with glenoid component shift and CPO were evaluated.

RESULTS

Glenoid component shift occurred from CT2 to CT3 in 78 (51%) of the 152 patients. CPO was seen at CT3 in 19 (13%) of the 152 patients, including 15 (19%) of the 78 with component shift. Walch B2 glenoids with a standard component and glenoids with higher preoperative retroversion were associated with a higher rate of shift, but not of CPO. B3 glenoids with an augmented component and glenoids with greater preoperative joint-line medialization were associated with CPO, but not with shift. More glenoid component joint-line medialization from CT2 to CT3 was associated with higher rates of shift and CPO. A greater absolute change in glenoid component inclination from CT2 to CT3 and a combined absolute glenoid component version and inclination change from CT2 to CT3 were associated with CPO. Neither glenoid component shift nor CPO was associated with worse clinical outcomes.

CONCLUSIONS

Postoperative 3D CT analysis demonstrated that glenoid component shift commonly occurs following anatomic TSA, with increased inclination the most common direction. Most (81%) of the patients with glenoid component shift did not develop CPO. Longer follow-up is needed to determine the relationships of glenoid component shift and CPO with loosening over time.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Computed tomographic evaluation of glenoid joint line restoration with glenoid bone grafting and reverse shoulder arthroplasty in patients with significant glenoid bone loss

BACKGROUND

Restoration of native glenohumeral joint line is important for a successful outcome after reverse shoulder arthroplasty (RSA). The aims of this study were to quantify the restoration of glenoid joint line after structural bone grafting and RSA, and to evaluate graft incorporation, correction of glenoid version, and rate of notching.

METHODS

This is a retrospective review of 21 patients who underwent RSA (20 primary, 1 revision) with glenoid bone grafting (15 autografts, 6 allografts). Grammont design implants and baseplate with long peg were used in all patients. Preoperative and postoperative 3D models were created using MIMICS 21.0. Preoperative defects were classified, and postoperative joint line restoration was assessed based on the lateral aspect of the base of the coracoid. Postoperative computed tomographic (CT) scans were evaluated for graft incorporation, version correction, and presence of notching.

RESULTS

Preoperative glenoid defects were classified as massive (5%), large (29%), moderate (52%), and small (14%). The average preoperative version was 8° of retroversion. The average postoperative version was 5° of retroversion. The average preoperative medialization was noted to be 8.4 mm medial to native joint line or 0.6 mm (range -16.8 to 13.2) lateral to the coracoid base. The postoperative CT scans demonstrated a mean joint line at 12.1 mm (range 1.3-22.4) lateral to the coracoid base. At the 3-month follow-up, all patients demonstrated graft incorporation on CT scans. Graft osteolysis was observed on CT scan in 4.8% of patients at a mean follow-up of 19.5 months.

DISCUSSION

Structural bone grafting of glenoid defect effectively re-creates the glenoid anatomy, restores glenoid bone stock, re-creates the true glenohumeral joint line, and corrects glenoid deformity. The use of bone grafting also allows lateralization of the baseplate and glenosphere, reducing the risk of severe scapular notching.

CONCLUSION

Restoration of the glenoid joint line was achieved in all patients. Glenoid bone grafting is a viable option for restoring glenoid joint line in cases of significant glenoid defects encountered during RSA.

Single-row vs. double-row refixation of the subscapularis tendon after primary anatomic shoulder arthroplasty

BACKGROUND

The postoperative integrity of the subscapularis tendon after primary anatomical shoulder arthroplasty has a significant effect on postoperative results. A transosseus Single Row Refixation technique (SRR) has shown up to 30% of partial tears in literature, a modified Double Row Refixation technique (DRR) has biomechanically shown a significantly reduced tear rate, but is yet to be proven in a clinical setting. Thus, we compared the SRR to the DRR technique using clinical outcome parameters and ultrasound examination.

MATERIALS AND METHODS

36 patients (40 shoulders; 20f, 16 m; øage: 66 years) were included in our retrospective cohort study. 20 shoulders were treated with the SRR technique (12f, 8 m; FU ø40.9 months) and 20 with the DRR technique (11f, 9 m; FU ø31.6 months). The SRR was performed with three to five transosseus mattress sutures. DRR consisted of two medial placed transosseus sutures and four laterally placed single tendon-to-tendon sutures. The postoperative subscapularis integrity was evaluated by ultrasound examination, the clinical outcome was assessed with the Constant-Murley Score (CS) and the American Shoulder and Elbow Surgeons Score (ASES).

RESULTS

The subscapularis tendon was intact in 14 patients (70%) after SRR, whereas 18 patients (90%) treated with the DRR demonstrated a sonographically intact postoperative subscapularis tendon. The CS was 61.4 points in the SRR cohort and 67.3 points in the DRR cohort (p = 0.314). No significant differences were found in both cohorts preoperative (øSRR: 21.3 points; øDRR: 16.2 points, p = 0.720) and postoperative absolute ASES Scores (øSRR: 70.2 points; øDRR: 73.0 points, p = 0.792). However, the DRR cohort showed a statistical tendency to a higher postoperative ASES increase than the SRR cohort (øSRR-ASES increase: 48.9 points; øDRR-ASES increase: 56.8 points, p = 0.067).

CONCLUSION

The results of this study show that application of the DRR technique can significantly reduce the total rate of postoperative subscapularis tears what effects a clinical tendency towards higher ASES improvements and a better range of motion compared to the SRR technique.

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.

Do glenoid retroversion and humeral subluxation affect outcomes following total shoulder arthroplasty?

Background

Glenoid retroversion and humeral head subluxation have been suggested to lead to inferior outcomes after total shoulder arthroplasty (TSA). There are limited data to support this suggestion. We investigated whether preoperative glenoid retroversion and humeral head subluxation are associated with inferior outcomes after TSA and whether change of retroversion influences outcomes after TSA.

Methods

Patients undergoing TSA with minimum 2-year follow-up were included from a prospectively collected institutional shoulder arthroplasty database. Retroversion and humeral head subluxation before and after surgery were measured on axillary radiographs. Postoperative radiographs were -evaluated for glenoid component loosening and compared between groups. Spearman correlations were determined between retroversion measurements and American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) scores. Patients were analyzed in groups based on retroversion and humeral head subluxation.

Results

There were 113 patients (50% follow-up rate) evaluated at 4.2 years postoperatively. The mean preoperative retroversion (15.3° ± 7.7°) was significantly higher than postoperative retroversion (10.0° ± 6.8°; P < .0001). There was no correlation between postoperative glenoid version or humeral head subluxation and ASES scores. For patients with preoperative retroversion of >15°, there was no difference in outcome scores based on postoperative retroversion. There were no differences in preoperative or postoperative version for patients with or without glenoid lucencies.

Discussion

We observed no significant relationship between postoperative glenoid retroversion or humeral head subluxation and clinical outcomes in patients following TSA. For patients with preoperative retroversion >15°, change of retroversion during TSA had no impact on their clinical outcomes at short-term follow-up.

Surgical Management of Glenohumeral Osteoarthritis With Glenoid Erosion and Static Posterior Subluxation (Walch B2): Techniques, Outcomes, and Survivorship Rates

The purpose of this study was to systematically assess the surgical techniques and outcomes related to the management of Walch B2 glenoids. PubMed, Medline, and Embase were searched from inception to July 2018. Overall, 24 studies (787 B2 glenoids) were identified. Revision-free survivorship was highest for reverse total shoulder arthroplasty (98.6%) and anatomic total shoulder arthroplasty with asymmetric reaming and a non-augmented glenoid implant (95.6%). Walch B2 glenoids are most commonly managed by asymmetric reaming in the context of anatomic total shoulder arthroplasty, and by the ream-and-run technique in hemiarthroplasty. The optimal treatment strategy remains elusive due to a lack of high-quality, comparative studies with long-term surveillance. [Orthopedics. 2020;43(4):e191-e201.].

Contracture and transient receptor potential channel upregulation in the anterior glenohumeral joint capsule of patients with end-stage osteoarthritis

BACKGROUND

During anatomic total shoulder arthroplasty (TSA) for primary glenohumeral osteoarthritis (GHOA), the anterior shoulder joint capsule (ASJC) is characterized grossly by contracture, synovitis, and fibrosis. In tissues that develop fibrosis, there is substantial cross-talk between macrophages, fibroblasts, and myofibroblasts, modulated by calcium signaling and transient receptor potential (TRP) channel signaling. The purpose of this study was to compare and characterize the degree of synovitis, inflammatory infiltrate, and TRP channel expression in ASJC harvested from shoulders with and without primary GHOA.

METHODS

The ASJC was resected from patients undergoing TSA for primary GHOA or other diagnoses and compared with ASJC from cadaveric donors with no history of shoulder pathology. ASJC was evaluated by immunohistochemistry to characterize synovial lining and capsular inflammatory cell infiltrate and fibrosis, and to evaluate for expression of TRPA1, TRPV1, and TRPV4, known to be involved in fibrosis in other tissues. Blinded sections were evaluated by 3 graders using a semiquantitative scale; then results were compared between diagnosis groups using nonparametric methods.

RESULTS

Compared with normal control, the ASJC in primary GHOA had significantly increased synovitis, fibrosis, mixed inflammatory cell infiltrate including multiple macrophages subsets, and upregulation of TRP channel expression.

CONCLUSION

These data support the clinical findings of ASJC and synovial fibrosis in primary GHOA, identify a mixed inflammatory response, and identify dysregulation of TRP channels in the synovium and joint capsule. Further studies will identify the role of synovial and capsular fibrosis early in the development of GHOA.

Reduction of scapulohumeral subluxation with posterior augmented glenoid implants in anatomic total shoulder arthroplasty: Short-term 3D comparison between pre- and post-operative CT

BACKGROUND

Failure rates in anatomic total shoulder arthroplasty (aTSA) are higher in case of asymmetric glenoid bone loss secondary to posterior wear, and in persistent static posterior subluxation of the humeral head (PSH).

HYPOTHESIS

This study aimed to test the hypothesis that the combined use of posterior augmented glenoid (PAG) implants with three-dimensional (3D) surgical planning and patient-specific instrumentation (PSI) guides helps reduce short-term PSH after aTSA in patients with type B2-B3 glenoids.

PATIENTS AND METHODS

We included nine consecutive patients with primary glenohumeral osteoarthritis and type B2 or B3 glenoids, who underwent aTSA with cemented keeled PAG implants (posterior augments of 15, 25, or 35 degrees). All patients underwent preoperative shoulder computed tomography (CT) scans, with 3D surgical planning coupled to PSI at the time of surgery. Postoperative shoulder CT scans were performed at an average of 14 weeks (range, 10-21 weeks). Scapulohumeral subluxation and glenoid version and inclination were measured in 3D, on both pre- and post-operative CT scans, using the same reliable quantitative method.

RESULTS

There was a significant decrease in scapulohumeral subluxation from 49±12% preoperatively to 22±17% postoperatively (p=0.0039), with a large effect size (Cohen's d=1.89). Preoperative glenoid version was corrected from -17.3±9.4 degrees to -5.2±7.5 degrees postoperatively. The absolute difference between the postoperative and surgically planned version and inclination was 5.4±3.6 degrees and 3.3±2.0 degrees, respectively.

DISCUSSION

The combined use of PAG implants with 3D preoperative planning and PSI results in a significant decrease in short-term PSH and glenoid version in patients with asymmetric posterior glenoid wear. We suggest that such implants should not be limited to posterior augmentation, because glenoid deficiency can also be observed in other glenoid sectors.

LEVEL OF EVIDENCE

IV, Basic science study.

A randomized controlled trial comparing subscapularis tenotomy with peel in anatomic shoulder arthroplasty

BACKGROUND

Controversy exists regarding the optimal technique of subscapularis tendon mobilization during anatomic shoulder arthroplasty. The purpose of this prospective, randomized, double-blind study was to compare internal rotation strength in the belly-press position and functional outcomes between the subscapularis tenotomy and subscapularis peel approaches during shoulder arthroplasty.

METHODS

Patients undergoing anatomic shoulder arthroplasty were randomized to either a tenotomy or peel approach. The primary outcome was internal rotation strength in the belly-press position, measured by an electronic handheld dynamometer at 24 months postoperatively. Secondary outcomes included the Western Ontario Osteoarthritis of the Shoulder (WOOS) index score, American Shoulder and Elbow Surgeons (ASES) score, range of motion, radiographic lucencies, and adverse events.

RESULTS

We randomized 100 patients to subscapularis tenotomy (n = 47) or peel (n = 53). Eighty-one percent of the cohort returned for 24 months' follow-up. Compared with baseline measures, mean internal rotation strength in the belly-press position and WOOS and ASES scores improved in both groups at final follow-up (P < .0001). Intention-to-treat analysis for internal rotation strength at 24 months revealed no significant difference (P = .57) between tenotomy (mean, 4.9 kg; SD, 3.8 kg) and peel (mean, 5.4 kg; SD, 3.9 kg). Comparison of WOOS and ASES scores demonstrated no significant differences between groups at any time point. The healing rates by ultrasound were 72% for tenotomy and 71% for peel (P = .99).

DISCUSSION

No statistically significant difference in internal rotation strength was identified between the tenotomy and peel groups. The secondary outcomes were not significantly different between groups.

Outcomes of Anatomic Total Shoulder Arthroplasty with B2 Glenoids: A Systematic Review

BACKGROUND

Total shoulder arthroplasty remains an effective procedure for shoulder pain relief. Despite the negative effect of abnormal glenoid morphology and specifically retroverted and posteriorly subluxated glenoids, there is no consensus for management of B2 glenoids in total shoulder arthroplasty. The purpose of this study was to compare the outcomes and complication rates for B2 glenoid techniques so as to provide a baseline understanding of the current state of treatment of this pathology.

METHODS

A systematic review evaluating outcomes of total shoulder arthroplasty with biconcave glenoids using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodology included searches up to December 31, 2015, of PubMed, Embase, MEDLINE, Cochrane Reviews, and Google Scholar. Nine articles met inclusion and exclusion criteria.

RESULTS

In this study, 239 total shoulder arthroplasties with B2 glenoids with a mean follow-up of 55.5 months (range, 24 to 91 months) were included. The mean patient age was 63.3 years (range, 55.8 to 68.7 years). Asymmetric reaming was performed in 127 glenoids, posterior bone-grafting was included in 53 glenoids, and 34 received an augmented glenoid component to correct glenoid retroversion and bone loss. Overall, the mean Constant and Neer scores improved from preoperative measures. Fifty-eight percent of patients had no loosening, and 42% had some loosening, although not all of these patients were symptomatic. Despite variation in outcome measures hindering treatment approach comparison, the posteriorly augmented glenoid was generally reported to provide better outcomes with few complications. Although posterior glenoid bone-grafting results in acceptable outcomes, it also represents the highest rate of complications. The revision rate was 15.6% for asymmetric reaming, 9.5% for posterior glenoid bone-grafting, and 0% for posteriorly augmented glenoids.

CONCLUSIONS

Surgical treatment of the B2 glenoid remains a challenge to the shoulder surgeon, with worse outcomes and higher complication rates. Longer follow-up, consistent outcome measures, and result stratification based on glenoid type may allow for direct comparison in the future.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Autografting for B2 Glenoids

The Walch B2 glenoid is characterized by a biconcave glenoid deformity, acquired glenoid retroversion, and posterior subluxation of the humeral head. Surgical reconstruction of the B2 glenoid is often challenging due to the complexity of the deformity. Bone graft augmentation using humeral head autograft is a valuable adjunct to anatomic total shoulder arthroplasty in the B2 glenoid, particularly in the young, highly active patient with severe glenoid retroversion (>25°–30°). Although this technique affords the ability to correct glenoid version and simultaneously enhances glenoid bone stock, it is technically challenging. The potential for graft-related complications also exists, which may further impact glenoid implant longevity and functional outcome. This review article aims to describe the B2 glenoid morphology, discuss the challenges in managing the B2 deformity, and provide further insight specifically regarding autografting at the time of anatomic total shoulder arthroplasty for reconstruction of the B2 glenoid.

Clinical and Radiographic Outcomes of a Posteriorly Augmented Glenoid Component in Anatomic Total Shoulder Arthroplasty for Primary Osteoarthritis with Posterior Glenoid Bone Loss

BACKGROUND

The primary objectives of this study were to evaluate the ability of a posteriorly stepped augmented glenoid component, used in patients with primary glenohumeral osteoarthritis with B2 or B3 glenoid morphology, to correct preoperative retroversion and humeral head subluxation and to identify factors associated with radiographic radiolucency and patient-reported clinical outcomes.

METHODS

We identified 71 shoulders with B2 or B3 glenoid morphology that underwent anatomic total shoulder arthroplasty with use of a posteriorly stepped augmented glenoid component and with a preoperative 3-dimensional computed tomography (3D-CT) scan and a minimum of 2 years of clinical and radiographic follow-up. The Penn Shoulder Score (PSS), shoulder range of motion, glenoid center-peg osteolysis, and postoperative version and humeral head subluxation were the main outcome variables of interest.

RESULTS

Follow-up was a median of 2.4 years (range, 1.9 to 5.7 years); the mean patient age at treatment was 65 ± 7 years (range, 51 to 80 years). PSS, range of motion, humeral head centering, and glenoid version were significantly improved among all patients (p < 0.0001). Patients with persistent posterior subluxation of the humeral head postoperatively had worse preoperative fatty infiltration of the teres minor and greater postoperative component retroversion (p < 0.05). Patients with center-peg osteolysis had more preoperative joint-line medialization and posterior glenoid bone loss (p < 0.05). Patients with more preoperative humeral head posterior subluxation had a lower PSS, adjusting for confounders (p < 0.05).

CONCLUSIONS

Posteriorly stepped augmented glenoid components can improve pathologic retroversion and posterior subluxation of the humeral head in B2 and B3 glenoids, with significant improvements found in clinical outcome scores at a minimum of 2 years of follow-up in the vast majority of patients.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Subscapularis Management in Total Shoulder Arthroplasty: Current Evidence Comparing Peel, Osteotomy, and Tenotomy

The optimal approach to management of the subscapularis in total shoulder arthroplasty (TSA) is controversial. Options include the subscapularis tenotomy, lesser tuberosity osteotomy (LTO), and peel. This review provides a summary of subscapularis anatomy and function, outcomes associated with subscapularis management options in TSA, and postoperative subscapularis deficiency. Based on the available literature, LTO appears to result in improved function and subscapularis integrity relative to tenotomy, while peel and LTO have generally led to equivalent outcomes. The highest level of evidence to date is derived from a randomized controlled trial that demonstrated that outcomes following peel and LTO were not significantly different. There is currently a paucity of high-quality evidence as most studies have consisted of small retrospective series with varying outcome measures. Furthermore, the optimal approach to establishing the diagnosis of subscapularis deficiency following TSA is unclear.

Subscapularis Insufficiency: What’s All the Fuss About?

There has been increase attention to the surgical treatment of the subscapularis (SSC) tendon with risk of postoperative dysfunction and early failures following shoulder arthroplasty. Studies investigating the clinical results after shoulder arthroplasty indicate that SSC tendon detachment or incision techniques and rehabilitation concepts may impair SSC recovery and consequently the postoperative function. In response to these results, technical modifications have been proposed and evaluated anatomically, biomechanically, and clinically. The aim of this article is to give an overview of current SSC take-down approaches, subsequent repair techniques, and postoperative rehabilitation protocols as well as to present the diagnostic algorithm and clinical impacts of the increasingly acknowledged condition of SSC insufficiency following shoulder arthroplasty procedures.

Total shoulder arthroplasty in patients with a B2 glenoid addressed with corrective reaming

BACKGROUND

This study describes the short-term functional and radiographic outcomes after total shoulder arthroplasty (TSA) in shoulders with a B2 glenoid deformity addressed with corrective reaming.

METHODS

We conducted a retrospective series of consecutive patients who underwent TSA with a Walch B2 glenoid quantified by computed tomography scan. All glenoid deformities were addressed using partially corrective glenoid reaming. Radiographic and functional outcome measures, including scores on the visual analog scale for pain, American Shoulder and Elbow Standardized Shoulder Assessment, and Simple Shoulder Test were collected.

RESULTS

Functional outcome scores were available for 59 of 92 eligible subjects (64%) at a mean of 50 months. The mean preoperative retroversion measured 18° (range, -1° to 36°), superior inclination was 8° (range, -11° to 27°), and posterior subluxation was 67% (range, 39%-91%). Mean visual analog scale improved from 7.4 to 1.4, the American Shoulder and Elbow Shoulder Standardized Assessment improved from 35.4 to 84.3, and the SST improved from 4.5 to 9.1. Radiographs were evaluated at a mean of 31 months: 38 had no glenoid radiolucent lines, 13 glenoids had grade 1, 2 had grade 2, and 5 had grade 3 lucencies. There was no difference in the rate of progression of glenoid radiolucencies between shoulders with a preoperative glenoid version of ≤20° (27.8%) compared with glenoids with >20° of retroversion (22.7%, P = .670). No shoulders were revised due to glenoid loosening or instability.

CONCLUSION

TSA with partial corrective glenoid reaming in selected shoulders with a B2 glenoid deformity resulted in excellent functional and radiographic outcomes at short-term follow-up, with a low risk of revision surgery.

Sequential 3-dimensional computed tomography analysis of implant position following total shoulder arthroplasty

BACKGROUND

Detection of postoperative component position and implant shift following total shoulder arthroplasty (TSA) can be challenging using routine imaging. The purpose of this study was to evaluate glenoid component position over time using 3-dimensional computed tomography (CT) analysis with minimum 2-year follow-up.

METHODS

Twenty patients underwent primary TSA with sequential CT scanning of the shoulder: a preoperative study, an immediate postoperative study within 2 weeks of surgery, and a postoperative study performed at minimum 2-year follow-up (CT3). Postoperative glenoid component position and central peg osteolysis were assessed across the immediate postoperative CT scan and CT3. Glenoids with evidence of component shift and/or grade 1 central peg osteolysis on CT3 were considered at risk of loosening.

RESULTS

Of the patients, 7 (35%) showed evidence of glenoid components at risk of loosening on CT3, 6 with component shift (3 with increased inclination alone, 1 with increased retroversion alone, and 2 with both increased inclination and retroversion). Significantly more patients with glenoid component shift had grade 1 central peg osteolysis on CT3 compared with those without shift (83% vs 7%, P = .002). One clinical failure occurred, with the patient undergoing revision to reverse TSA for rotator cuff deficiency.

CONCLUSIONS

Three-dimensional CT imaging analysis following TSA identified changes in glenoid component position over time, with inclination being the most common direction of shift and grade 1 central peg osteolysis commonly associated with shift. These findings raise concern for glenoids at risk of loosening, but further follow-up is needed to determine the long-term clinical impact of these findings.

[The ABC guide for the treatment of posterior shoulder instability]

BACKGROUND

Posterior glenohumeral instability (PGHI) is an often unrecognized or misdiagnosed type of shoulder instability due to its heterogenic clinical and radiological presentation.

CLASSIFICATION

The ABC classification for PGHI is based on the different pathomechanisms and recommended treatment standards and is therefore a guide to finding the correct diagnosis and therapy for affected patients. There are different types of PGHI: A (first time), B (dynamic), C (static). These groups are further classified based on pathomechanical principles: A1: subluxation, A2: dislocation; B1: functional, B2: structural; C1: constitutional, C2: acquired.

THERAPY

In patients with type 1 PGHI (A1, B1, C1) conservative treatment is recommended while in patients with type 2 PGHI (A2, B2, C2) surgical treatment can be considered based on structural defects, clinical symptoms, chronicity, age, functional demand, and patient-specific health status. In addition it has to be considered, that there is the possibility of coexisting or overlapping subtypes as well as the chance of progression from one category into another over time.

Walch B0 glenoid: pre-osteoarthritic posterior subluxation of the humeral head

The management of primary osteoarthritis of the shoulder has been well investigated. However, the etiology and management of posterior humeral head subluxation in the context of primary glenohumeral osteoarthritis remain controversial. The finding of static posterior subluxation of the humeral head before the development of posterior bone erosion of the glenoid in young men with radiographic findings of primary osteoarthritis has been described as arthrogenic posterior subluxation of the humeral head. It demonstrates the earliest form of the osteoarthritic evolution, and an excessive glenoid retroversion is the only probable cause of this static subluxation, although this is controversial. The clinical relevance of these findings is important in allowing the identification of patients at risk for development of glenohumeral osteoarthritis and in developing an early treatment for the subluxation to try to alter the natural course of this disease. The aim of our summary paper was to review the current literature on this matter in an attempt to better understand the pathophysiologic mechanism of this condition, which we named pre-osteoarthritic posterior subluxation of the humeral head, or Walch B-zero (B0) glenoid. It appears that Walch B0 glenoid is a pathologic condition (initially dynamic, eventually evolving into a static condition) that may lead to posterior erosion of the glenoid, taking place once there is asymmetric increased posterior glenohumeral contact forces and possibly associated with increased glenoid retroversion.

Does Postoperative Glenoid Retroversion Affect the 2-Year Clinical and Radiographic Outcomes for Total Shoulder Arthroplasty?

BACKGROUND

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.

QUESTIONS/PURPOSES

In a population of patients undergoing TSA in whom no specific efforts were made to change the version of the glenoid, we 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.

METHODS

Between August 24, 2010 and October 22, 2013, information for 201 TSAs performed using a standard all-polyethylene pegged glenoid component were entered in a longitudinally maintained database. 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. These 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, or history of prior surgery from those included in the analysis. Preoperative retroversion measurements were available for 11 (11 shoulders) of the 22 excluded patients. For these 11 shoulders, the mean (± SD) retroversion was 15.8° ± 14.6°, five had less than 15°, and six had more than 15° retroversion. We analyzed the remaining 71 TSAs, comparing the 21 in which the glenoid component was implanted in 15° 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 the 2-year followup (mean ± SD, 2.5 ± 0.6 years; range, 18-36 months), we determined the latest SST scores and preoperative to postoperative improvement in SST scores, the percentage of maximal possible improvement, glenoid component radiolucencies, posterior humeral head decentering, and percentages of shoulders having revision surgery. Radiographic measurements were performed by three orthopaedic surgeons who were not involved in the care of these patients. The primary study endpoint was the preoperative to postoperative improvement in the SST score.

RESULTS

With the numbers available, 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 mean difference in improvement between the two groups was 0.9 (95% CI, - 2.5 to 0.7; p = 0.412). 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 mean difference between the two groups was 3% (95% CI, - 18% to 12%; p = 0.857). 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. With the numbers available, 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). With the numbers available, 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).

CONCLUSION

In this small series of TSAs, postoperative glenoid retroversion was not associated with inferior clinical results at 2 years after surgery. This suggests that it may be possible to effectively manage arthritic glenohumeral joints without specific attempts to modify glenoid version. Larger, longer-term studies will be necessary to further explore the results of this approach.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Survivorship of Hemiarthroplasty With Concentric Glenoid Reaming for Glenohumeral Arthritis in Young, Active Patients With a Biconcave Glenoid

INTRODUCTION

Hemiarthroplasty with concentric glenoid reaming (known as "ream and run") may be an option for treating glenohumeral arthritis in younger patients with a biconcave glenoid. The goal of this study was to evaluate early results of this technique.

METHODS

Two senior, fellowship-trained shoulder surgeons (G.R.W. and M.D.L.) performed a retrospective review of 23 patients (24 shoulders) with a biconcave glenoid and end-stage degenerative glenohumeral arthritis treated with hemiarthroplasty with concentric glenoid reaming. The mean patient age at the time of surgery was 50 years. We evaluated the Penn Shoulder Score (PSS), Single Assessment Numeric Evaluation (SANE) score, and Simple Shoulder Test (SST) score or the time to revision surgery.

RESULTS

Twenty-four humeral hemiarthroplasties with concentric glenoid reaming were performed in 23 patients. Twenty patients (21 shoulders) reached the end point of 2-year follow-up or revision surgery. Six shoulders (25%) required revision surgery at an average of 2.7 years (range, 0.7 to 7.2 years), and three were lost to follow-up. The remaining 14 patients (15 shoulders) were followed up for an average of 3.7 years (range, 2.3 to 4.9 years). At 2-year follow-up, these 15 shoulders did not require revision surgery and had an average SANE score, PSS, and SST score of 74.5%, 82.9, and 10.4, respectively. Increasing age correlated positively with the SANE score (r = 0.62; P = 0.015), PSS (r = 0.52; P = 0.047), and SST score (r = 0.63; P = 0.012). Early postoperative forward elevation correlated weakly with the PSS (r = 0.24; P = 0.395), and early postoperative external rotation correlated moderately with the PSS (r = 0.53; P = 0.044). Final external rotation correlated moderately with the PSS (r = 0.69; P = 0.005).

DISCUSSION

Modest results were achieved with a hemiarthroplasty and concentric glenoid reaming in young patients with end-stage glenohumeral arthritis and a biconcave glenoid. Younger age and stiffness were associated with worse outcomes. Given the high revision rate and the percentage of patients who had unsatisfactory results, this procedure should be performed only after careful patient selection. Patients who are willing and able to undergo aggressive physical therapy focused on achieving early range of motion are more likely to have a satisfactory outcome after humeral hemiarthroplasty with concentric glenoid reaming.

Survival of the pegged glenoid component in shoulder arthroplasty: part II

BACKGROUND

Loosening of the glenoid component is a primary reason for failure of an anatomic shoulder arthroplasty. Pegged glenoids were designed in an effort to outperform keeled components. This study evaluated the midterm clinical and radiographic survival of a single implant design with implantation of an in-line pegged glenoid component and identified risk factors for radiographic loosening and clinical failure.

MATERIALS AND METHODS

There were 330 total shoulder arthroplasties that had been implanted with a cemented, all-polyethylene, in-line pegged glenoid component evaluated with an average clinical follow-up of 7.2 years. Of these shoulders, 287 had presurgical, initial postsurgical, and late postsurgical radiographs (mean radiographic follow-up, 7.0 years).

RESULTS

At most recent follow-up, 30 glenoid components had been revised for aseptic loosening. This translated to a rate of glenoid component survival free from revision for all 330 shoulders of 99% at 5 years and 83% at 10 years. Of 287 glenoid components, 120 were considered loose on the basis of radiographic evaluation. Four humeral components were considered loose. Component survival (Kaplan-Meier) free from radiographic failure at 5 and 10 years was 92% and 43%. Severe presurgical glenoid erosion (Walch A2, B2, C) and patient age <65 years were risk factors for radiographic failure. Late humeral head subluxation was associated with radiographic failure.

CONCLUSION

Despite the predominant thinking that pegged glenoid components may be superior to keeled designs, midterm radiographic and clinical failure rates were high with this pegged component design, particularly after 5 years. Advanced presurgical glenoid erosion and younger patient age are risk factors for radiographic loosening. Revision rates underestimate radiographic glenoid loosening.

Interest in the glenoid hull method for analyzing humeral subluxation in primary glenohumeral osteoarthritis

BACKGROUND

Posterior humeral subluxation is the main cause of failure of total shoulder arthroplasty. We aimed to compare humeral head subluxation in various reference planes and to search for a correlation with retroversion, inclination, and glenoid wear.

MATERIALS AND METHODS

We included 109 computed tomography scans of primary glenohumeral osteoarthritis and 97 of shoulder problems unrelated to shoulder osteoarthritis (controls); all computed tomography scans were reconstructed in the anatomic scapular plane and the glenoid hull plane that we defined. In both planes, we measured retroversion, inclination, glenohumeral offset (Walch index), and scapulohumeral offset.

RESULTS

Retroversion in the scapular plane (Friedman method) was lower than that in the glenoid hull plane for controls and for arthritic shoulders. The threshold of scapulohumeral subluxation was 60% and 65% in the scapular plane and glenoid hull plane, respectively. The mean upward inclination was lower in the scapular plane (Churchill method) than in the glenoid hull plane (Maurer method). In the glenoid hull plane, 35% of type A2 glenoids showed glenohumeral offset greater than 75%, with mean retroversion of 25.6° ± 6° as compared with 7.5° ± 7.2° for the "centered" type A2 glenoids (P < .0001) and an upward inclination of -1.4° ± 8° and 6.3° ± 7° (P = .03), respectively. The correlation between retroversion and scapulohumeral offset was r = 0.64 in the glenoid hull plane and r = 0.59 in the scapular plane (P < .05).

CONCLUSION

Measurement in the glenoid hull plane may be more accurate than in the scapular plane. Thus, the glenoid hull method allows for better understanding type B3 of the modified Walch classification.

The three-dimensional glenohumeral subluxation index in primary osteoarthritis of the shoulder

BACKGROUND

Assessment of glenohumeral subluxation is essential in preoperative planning of total shoulder arthroplasty. The purpose of this study was to evaluate a 3-dimensional (3D) glenohumeral subluxation index (GHSI) in shoulders with primary osteoarthritis (OA) and its relationship with morbid glenoid retroversion.

METHODS

The 3D computed tomography reconstructions of 120 healthy shoulders and 110 shoulders with primary glenohumeral arthritis (OA group), classified according to Walch's glenoid morphology, were analyzed. The 3D GHSI was assessed by measuring posterior decentering of the humeral head in relation to the native glenoid in each subject, and its correlation to morbid glenoid version was calculated.

RESULTS

The reproducible 3D GHSI (intraclass correlation coefficients ≥ 0.842) showed a posterior decentering of the humeral head in the OA population and in each type of glenoid morphology (P ≤ .005). A moderate correlation was observed in the OA group (r = -0.542; P < .001), but weak linear relationships were found for different glenoid morphology types (r between 0.041 and -0.307). Type A shoulders (r = -0.375; P = .006) correlated better than type B shoulders (r =  -0.217; P = .104). After shoulders were subcategorized according to a threshold for 3D subluxation, the posteriorly subluxated group increased its correlation (r = -0.438; P < .001), whereas the centered shoulders still exhibited no relationship (r = -0.192; P = .329).

CONCLUSIONS

Posterior humeral head decentering in relation to the native glenoid is present in each glenoid morphology type. Grouping measures according to morphology type and 3D subluxation showed at best moderate correlations between morbid version and 3D GHSI.

Radiographic results of augmented all-polyethylene glenoids in the presence of posterior glenoid bone loss during total shoulder arthroplasty

BACKGROUND

Chronic osteoarthritis can result in glenohumeral subluxation and loss of posterior glenoid bone. This can alter normal glenohumeral biomechanics and affect the stress placed on the glenoid implant after total shoulder arthroplasty. This study evaluated the clinical and radiographic results of an augmented all-polyethylene glenoid for the treatment of glenoid osteoarthritis in the presence of posterior glenoid bone loss and determined whether any failures or complications occurred with short-term follow-up.

METHODS

During a 2-year period, 21 patients were treated with an augmented glenoid for an index diagnosis of osteoarthritis with a biconcave glenoid and average posterior glenoid bone loss of 4.7 mm. Clinical outcomes were recorded for the American Shoulder and Elbow Surgeons Shoulder Assessment, Simple Shoulder Test, and active motion. Radiographic analysis included glenoid version, humeral head subluxation, component seating, ingrowth, and loosening.

RESULTS

Significant improvements were demonstrated for American Shoulder and Elbow Surgeons Shoulder Assessment (52.3), Simple Shoulder Test (8.1), forward flexion (50°), external rotation (32°), and pain. Radiographic improvements were found for glenoid version (12°), humeral scapular alignment (23%), and humeral glenoid alignment (8%). Central peg ingrowth was demonstrated in all patients, and complete component seating was achieved in 19 patients. No complications were encountered, and no clinical or radiographic failures were identified.

CONCLUSION

Augmented polyethylene glenoid components demonstrated improved clinical outcome, without implant failure or complications, during short-term follow-up.

ABC classification of posterior shoulder instability

Posterior glenohumeral instability (PGHI) is a commonly under- and misdiagnosed pathology owing to its variety of clinical presentations. In order to facilitate diagnosis and treatment, the simple yet comprehensive ABC classification for PGHI is based on the underlying pathomechanical principles and current standard of treatment. Three main groups of PGHI are distinguished based on the type of instability: A (first time), B (dynamic), C (static). Two subtypes further differentiate these groups in terms of their specific pathomechanism and provide a guideline in the choice of appropriate treatment: A (1, subluxation; 2, dislocation), B (1, functional; 2, structural), C (1, constitutional; 2, acquired). While conservative treatment is warranted in most patients with type 1 PGHI (A1, B1, C1), surgical treatment should be considered on an individual basis in patients with type 2 PGHI (A2, B2, C2), while keeping in mind that the different groups and subtypes can overlap, co-exist, or even progress from one to another over time. Of course the necessity for surgical treatment depends on the extent of the structural defects, on the severity of symptoms, on the chronicity, as well as on patient-specific functional demand, age, and health status. Nonetheless, the ABC classification helps to correctly diagnose the type of PGHI and provides a guideline for the generally recommended type of treatment.

Nerve supply of the subscapularis during anterior shoulder surgery: definition of a potential risk area

PURPOSE

The purpose of the study was to evaluate the position of the subscapular nerves relative to surgical landmarks during exposure and to analyze the pattern of innervation of the subscapularis to avoid injury during anterior shoulder surgery.

METHODS

20 embalmed human cadaveric shoulder specimens were used in the study. The muscular insertions of the subscapular nerves were marked and their closest branches to the musculotendinous junction and the coracoid process were measured in horizontal and vertical distances. In addition, the innervation pattern of each specimen was documented.

RESULTS

14/20 specimens showed an innervation of the subscapularis with an upper, middle and lower subscapular nerve branch. Even though the nerve branches were in average more than 2 cm medial to the musculotendinous junction, minimal distances of 1.1-1.3 cm were found. The mean vertical distance as measured from the medial base of the coracoid to the nerve innervation point into the muscle was 0.7 cm for the upper nerve branch, 2.2 cm for the middle nerve branch and 4.4 cm for the lower nerve branch.

CONCLUSIONS

The subscapularis has a variable nerve supply, which increases the risk of muscle denervation during open shoulder surgery. Dissection or release should be avoided at the anterior aspect of the subscapularis muscle more than 1 cm medial to the musculotendinous junction. In approaches with a horizontal incision of the subscapularis, splitting should be performed at a vertical distance of 3.2-3.6 cm to the coracoid base to avoid iatrogenic subscapular nerve injuries.

Management of intraoperative posterior decentering in shoulder arthroplasty using anteriorly eccentric humeral head components

BACKGROUND

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. 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% ± 7.9% to 0.9% ± 2.3% postoperatively (P < .001). SST scores improved from 4.8 ± 2.3 to 10.0 ± 2.3 (P < .001). Preoperative posterior humeral head decentering did not correlate with preoperative glenoid version. Glenoid retroversion was 19.8° ± 8.9° preoperatively and 15.5° ± 7.5° postoperatively.

CONCLUSIONS

Posterior decentering identified at surgery when standard trial components are in place can be addressed by replacing the anatomic humeral head with an anteriorly eccentric humeral head component.

Observation of initial postoperative radiolucent lines using a modern pegged-glenoid design

PURPOSE

Glenoid component loosening remains a common mode of failure for total shoulder arthroplasty and has inspired improvements in implant design, instrumentation, and surgical technique. The purpose of this manuscript was to evaluate the incidence of radiolucent lines and glenoid seating on initial postoperative radiographs using a modern pegged-glenoid design, instrumentation, and surgical technique.

MATERIALS AND METHODS

We performed a retrospective analysis of a consecutive series of 100 pegged-glenoid total shoulder replacements. In cases of excessive glenoid version, the glenoid was asymmetrically reamed to recreate more normal version. Initial postoperative radiographs were evaluated for the presence of radiolucent lines and completeness of glenoid seating. The preoperative glenoid version measured on axial computed tomography (CT) scans was used to compare differences in version among those with complete and incompletely seated glenoids.

RESULTS

The rate of radiolucent lines observed on postoperative radiographs was 0%. Complete glenoid seating (Grade A) was observed in 81 patients (observer 1) and 82 patients (observer 2). Measurements of preoperative CT scans found a higher percentage of abnormal glenoid version for incompletely seated glenoids (47%) than completely seated glenoids (34%) but no significant difference (P = 0.327). The mean preoperative glenoid retroversion for incompletely seated glenoids was 12.1° and 9.1° for completely seated glenoids (P = 0.263).

CONCLUSIONS

Modern surgical techniques, surgical instrumentation, and peg glenoid design have facilitated the ability to eliminate radiolucent lines on initial postoperative radiographs with high rates of complete seating of glenoid components. Incomplete seating may be related to incomplete correction of glenoid version.

Posterior glenoid wear in total shoulder arthroplasty: eccentric anterior reaming is superior to posterior augment

BACKGROUND

Uncorrected glenoid retroversion during total shoulder arthroplasty may lead to an increased likelihood of glenoid prosthetic loosening. Augmented glenoid components seek to correct retroversion to address posterior glenoid bone loss, but few biomechanical studies have evaluated their performance.

QUESTIONS/PURPOSES

We compared the use of augmented glenoid components with eccentric reaming with standard glenoid components in a posterior glenoid wear model. The primary outcome for biomechanical stability in this model was assessed by (1) implant edge displacement in superior and inferior edge loading at intervals up to 100,000 cycles, with secondary outcomes including (2) implant edge load during superior and inferior translation at intervals up to 100,000 cycles, and (3) incidence of glenoid fracture during implant preparation and after cyclic loading.

METHODS

A 12°-posterior glenoid defect was created in 12 composite scapulae, and the specimens were divided in two equal groups. In the posterior augment group, glenoid version was corrected to 8° and an 8°-augmented polyethylene glenoid component was placed. In the eccentric reaming group, anterior glenoid reaming was performed to neutral version and a standard polyethylene glenoid component was placed. Specimens were cyclically loaded in the superoinferior direction to 100,000 cycles. Superior and inferior glenoid edge displacements were recorded.

RESULTS

Surviving specimens in the posterior augment group showed greater displacement than the eccentric reaming group of superior (1.01 ± 0.02 [95% CI, 0.89-1.13] versus 0.83 ± 0.10 [95% CI, 0.72-0.94 mm]; mean difference, 0.18 mm; p = 0.025) and inferior markers (1.36 ± 0.05 [95% CI, 1.24-1.48] versus 1.20 ± 0.09 [95% CI, 1.09-1.32 mm]; mean difference, 0.16 mm; p = 0.038) during superior edge loading and greater displacement of the superior marker during inferior edge loading (1.44 ± 0.06 [95% CI, 1.28-1.59] versus 1.16 ± 0.11 [95% CI, 1.02-1.30 mm]; mean difference, 0.28 mm; p = 0.009) at 100,000 cycles. No difference was seen with the inferior marker during inferior edge loading (0.93 ± 0.15 [95% CI, 0.56-1.29] versus 0.78 ± 0.06 [95% CI, 0.70-0.85 mm]; mean difference, 0.15 mm; p = 0.079). No differences in implant edge load were seen during superior and inferior loading. There were no instances of glenoid vault fracture in either group during implant preparation; however, a greater number of specimens in the eccentric reaming group were able to achieve the final 100,000 time without catastrophic fracture than those in the posterior augment group.

CONCLUSIONS

When addressing posterior glenoid wear in surrogate scapula models, use of angle-backed augmented glenoid components results in accelerated implant loosening compared with neutral-version glenoid after eccentric reaming, as shown by increased implant edge displacement at analogous times.

CLINICAL RELEVANCE

Angle-backed components may introduce shear stress and potentially compromise stability. Additional in vitro and comparative long-term clinical followup studies are needed to further evaluate this component design.

Glenoid bone loss in anatomic shoulder arthroplasty: literature review and surgical technique

Despite major advances in total shoulder arthroplasty, management of severe posterior glenoid bone loss remains controversial. Several companies have provided alternative treatment options for type C glenoids associated with posterior subluxation of the humeral head. However, preoperative planning, proper selection of glenoid size, and recognition of the operative pitfalls are crucial for successful outcomes. A review of the literature and presentation of the surgical technique for the management of severe posterior glenoid bone loss are presented.

Importance of a three-dimensional measure of humeral head subluxation in osteoarthritic shoulders

HYPOTHESIS

During total shoulder arthroplasty (TSA), humeral head subluxation may be difficult to manage. Furthermore, there is a risk for postoperative recurrence of subluxation, affecting the outcome of TSA. An accurate evaluation of the subluxation is necessary to evaluate this risk. Currently, subluxation is measured in 2 dimensions (2D), usually relative to the glenoid face. The goal of this study was to extend this measure to 3 dimensions (3D) to compare glenohumeral and scapulohumeral subluxation and to evaluate the association of subluxation with the glenoid version.

MATERIALS AND METHODS

The study analyzed 112 computed tomography scans of osteoarthritic shoulders. We extended the usual 2D definition of glenohumeral subluxation, scapulohumeral subluxation, and glenoid version by measuring their orientation in 3D relative to the scapular plane and the scapular axis. We evaluated statistical associations between subluxation and version in 2D and 3D.

RESULTS

Orientation of subluxation and version covered all sectors of the glenoid surface. Scapulohumeral subluxation and glenoid version were highly correlated in amplitude (R(2) = 0.71; P < .01) and in orientation (R(2) = 0.86; P < .01). Approximately every degree of glenoid version induced 1% of scapulohumeral subluxation in the same orientation of the version. Conversely, glenohumeral subluxation was not correlated to glenoid version in 2D or in 3D.

CONCLUSIONS

Orientation of the humeral subluxation is rarely within the arbitrary computed tomography plane and should therefore be measured in 3D to detect out-of-plane subluxation. Scapulohumeral subluxation and glenoid version measured in 3D could bring valuable information for decision making during TSA.

Failure of the lesser tuberosity osteotomy after total shoulder arthroplasty

BACKGROUND

Lesser tuberosity osteotomy (LTO) as an approach during total shoulder arthroplasty (TSA) is a reliable technique with strong biomechanical fixation and a low failure rate. Complications have been infrequently reported in the literature.

METHODS

We report a case series of 5 patients who sustained failure of the LTO repair after primary TSA. The data on the patient demographic characteristics, surgical technique, postoperative care, revision surgery, and clinical outcomes are reported.

RESULTS

The mean age of the 5 patients was 52 years, all patients were men, and the mean body mass index was 28 kg/m(2). They were followed up for a mean of 29 months (range, 24-38 months). The mean time from initial TSA to diagnosis of LTO failure was 9 weeks (range, 5-12 weeks). Two patients reported no trauma, 2 had minor trauma (using a pulley, rolling over in bed), and 1 sustained a fall. At the latest follow-up, the mean visual analog scale; Single Assessment Numeric Evaluation; University of California, Los Angeles; and American Shoulder and Elbow Surgeons scores were 4 (range, 0-6), 48 (range, 20-70), 19 (range, 11-22), and 63 (range, 48-83), respectively. Only 1 patient required no additional procedures beyond the revision LTO repair. Another patient required a second revision LTO repair. The remaining 3 patients either underwent or were recommended to undergo reverse arthroplasty.

CONCLUSION

Failure of the LTO repair after TSA may possibly be an under-reported complication that is associated with poor clinical outcomes and limited options for revision surgery. In patients with a high risk of LTO failure, considerations should be made to augment the LTO repair during the index TSA procedure.