Medium-term clinical and radiographic outcomes of a cementless prosthesis with a 140° neck-shaft angle in reverse total shoulder arthroplasty

BACKGROUND

The design of humeral implants has evolved from the initial Grammont design, notably regarding the neck-shaft angle (NSA) and through the use of cementless prostheses. Stress shielding was frequently reported with cementless implants, the 2 main risk factors being humeral stem misalignment and high filling ratios. Our hypothesis was that standard length cementless stems with an NSA of 140° would facilitate good alignment with moderate filling ratios, thereby limiting stress shielding and ensuring good clinical outcomes.

METHODS

A single-center retrospective study was conducted of patients who underwent reverse total shoulder arthroplasty between January 2015 and August 2017, with at least 2 years' follow-up. Clinical evaluations included range of motion measurements and Constant and subjective shoulder values scores. Frontal alignment was assessed in terms of the angle (α) between axes of the stem and of the humerus. Filling ratios were measured in the metaphysis of the humerus, in the diaphysis, and at the distal end of the stem and considered excessive above 0.7. Stress shielding was evidenced radiographically by the observation of medial cortical narrowing, medial metaphysis thinning, lateral metaphysis thinning or under-the-baseplate osteolysis.

RESULTS

Eighty-two shoulders were included and 70 had radiographic follow-up data available. The mean patient age was 78 years and 63/81 patients (78%) were female. The mean follow-up time was 39 ± 7 months. The mean α angle was 1.4° ± 0.9° and was less than 5° in all cases. The mean metaphyseal, diaphyseal, and distal filling ratios were 0.61 ± 0.06, 0.70 ± 0.08, and 0.64 ± 0.09, respectively. The mean Constant score improved from 28 ± 11 preoperatively to 64 ± 14 at last follow-up. The mean subjective shoulder values score at last follow-up was 81 ± 12. Seventy-nine percent of patients (55/70) had at least 1 form of stress-shielding related, which were not associated with clinical outcomes, apart from lateral metaphysis thinning, which was associated with lower active anterior elevation (mean, 106° ± 30° vs. 126° ± 28°; P = .01) and lower Constant scores (mean, 56 ± 17 vs. 65 ± 14; P = .06).

CONCLUSION

The use of cementless reverse shoulder prostheses with a NSA of 140° was associated with good clinical outcomes at 2 years' follow-up. The prosthesis stem was correctly aligned with the humeral axis and the filling ratios were <0.7 in all cases. Stress-shielding was common but, apart from lateral metaphysis thinning, this had no impact on clinical outcomes.

Reverse shoulder arthroplasty renders better clinical scores at a minimum follow-up of two years for patients with no rotator cuff deficiency operated by the deltopectoral approach

PURPOSE

The purpose of this multi-centre study was to report outcomes of a large cohort of reverse shoulder arthroplasty (RSA) at a minimum follow-up of two years and to determine patient and surgical factors that influence postoperative outcomes. The hypothesis was that surgical indication, surgical approach, and implant design would affect clinical outcomes significantly.

METHODS

The authors reviewed records of 743 RSAs in patients with primary osteoarthritis (OA) with or without rotator cuff (RC) tears, secondary OA due to RC tears, and irreparable massive rotator cuff tears (mRCT). The deltopectoral (DP) approach was used in 540 and the anterosuperior (AS) approach in 203. Pre- and postoperative Constant scores (CS) were recorded. Multivariable linear analyses were performed to determine if CS was associated with indications for surgery, surgical approach, or implant design.

RESULTS

Of the 743 shoulders, 193 (25.7%) were lost to follow-up, 16 (2.1%) died, and 33 (4.4%) were revised, leaving 501 for analysis. At a mean follow-up of 3.2 ± 0.9 years, net improvement in CS was 29.2 ± 17.0. Multivariable analyses revealed that postoperative CS decreased with age and was worse in shoulders that had preoperative rotator cuff deficiency and in shoulders operated by the AS approach. Multivariable analyses also revealed worse net improvement in shoulders operated for secondary OA due to RC tears or for irreparable mRCT, as well as shoulders operated by the AS approach.

CONCLUSION

This large multi-centre study confirms that, at two or more years following RSA, Constant scores are not associated with implant design, but rather with rotator cuff deficiency and surgical approach. Multivariable analysis revealed that postoperative CS was worse for shoulders with preoperative rotator cuff deficiency and for shoulders operated by the AS approach. Multivariable analysis also revealed that net improvement in CS was worse in shoulders treated for secondary OA due to RC tears and for shoulders with irreparable mRCT, as well as for shoulders operated by the AS approach.

Using standard-length compactors to implant short humeral stems in total shoulder arthroplasty: A cadaver study of humeral stem alignment

Background

Short-stem implants in shoulder arthroplasty were recently developed and reported clinical outcomes are good. However, radiological analysis often reveals humeral stem misalignment in the frontal plane, along with high filling ratios that can lead to proximal bone remodeling under stress shielding. The aim of this cadaveric study was to test whether using compactors for standard-length (> 100 mm) stems to implant short (< 100 mm) stems reduces the risk of stem misalignment without compromising in terms of a higher filling ratio.

Methods

In a cadaveric study, twenty short stems were implanted using instrumentation for standard-length stems. Alignment and filling ratios were evaluated on anteroposterior radiographs for both the compactors and the stems. The angular deviations (α) from the humeral axis of the compactors and the short stems were measured. Misalignment was defined as |α| > 5°. Metaphyseal and diaphyseal filling ratios were calculated and defined as either high (≥ 0.7) or low (< 0.7).

Results

The median angular deviations of the compactors and the short stems were respectively 1.6° (range, 0.03 to 5.9°) and 1.3° (range, 0.3 to 9.6°). Nineteen of the 20 compactors (95%) and 17/20 short stems (85%) were correctly aligned. The proportions of correctly aligned compactors and stems were not significantly different (95% CI, −0.33 to 0.11; Z-test of proportions p = .60), and the respective angular deviations were significantly correlated (Spearman ρ = .60, p = 0.006). The diaphyseal and metaphyseal filling ratios of the compactors and the stems were all low.

Conclusions

In this series of 20 implants in cadavers, the narrow short humeral stems implanted with compactors for standard-length stems were correctly aligned with the humeral axis. This approach may be a way to achieve both correct frontal alignment and low filling ratios.

Bony increased-offset reverse shoulder arthroplasty (BIO-RSA) associated with eccentric glenosphere and an onlay 135° humeral component : Clinical and Radiological Outcomes at a minimum 2 year follow-up

Background

Various implant designs have been proposed to increase active range of motion (ROM) and avoid notching in patients treated by reverse total shoulder arthroplasty (RSA). The purpose of this study was to investigate the efficacy and safety of an onlay prosthesis design combining a 135° humeral neck-shaft angle with the glenoid component lateralized and inferiorized.

Methods

A retrospective descriptive study was conducted of the clinical and radiological outcomes at the final follow-up (≥24 months) of all RSAs performed by the same surgeon between September 2015 and December 2016 in the study center. At the last follow-up, patients were clinically assessed for ROM, Constant score, and subjective shoulder value and radiologically for scapular notching and glenoid radiolucent lines. Patients were followed up radiographically at 1 month and clinically at between 6 and 12 months (midterm) and again at between 24 and 48 months (final follow-up). Scapular notching was graded as per the Sirveaux classification at the last follow-up on anterior-posterior radiographs.

Results

Seventy-nine RSAs were included with a mean follow-up time of 31 months. The mean Constant score at the final follow-up was 42 points higher than before surgery (69 vs. 27, P < .001). There were also significant postoperative improvements in ROM (active anterior elevation, active external rotation, and active internal rotation). The final means for motions were 133° for active anterior elevation, 32° active external rotation, and level 7 for active internal rotation. The overall notching rate was 3% (2/67), and there were no cases of severe notching. Radiolucent lines were observed in 8 of 70 prostheses (11.5%) around the peg, and they were observed in 9 prostheses (13%) around the screws. Among the 79 RSAs included, there were 11 complications (13.9%) (two infections, two fractures, four cases of glenoid component loosening, and three cases of instability), 2 reoperations, and 4 prosthesis revisions.

Conclusion

This study shows that an RSA design with a 135° humeral neck-shaft angle and an inferiorized and lateralized glenoid component is associated with significant improvements in active ROM, especially in rotation, and a low notching rate. However, rates of 3.8% for dislocation and 5% for glenoid loosening are certainly a concern at such a short follow-up of two years. Future studies with a larger population are needed to confirm these rates.

Three-Dimensional Upper Body Kinematics and Inter-articular Kinematic Sequence During a Canoe Polo Throw

Canoe polo is an increasingly popular discipline requiring both kayaking and ball-handling skills. While the kinematics of the upper body during throw has been investigated for several overhead sports, the canoe polo throw has still to be studied. Therefore, the aim of this study is to analyze the canoe polo throw kinematics in terms of angles and inter-articular sequencing to understand its specificity. A secondary aim was to investigate whether adding pelvis mobility has an impact. Nineteen male players of canoe polo were equipped with reflective body markers for the throw analysis. They performed 5 throws with the pelvis fixed and 5 throws with additional pelvic mobility in rotation around a vertical axis. Inverse kinematics was performed with OpenSim providing pelvis, trunk, and glenohumeral rotations. Angular velocities were calculated to build the inter-articular sequences relative to these throws. Statistical parametric mapping was used to assess the effect of pelvis mobility on the throwing kinematics. Similar kinematics patterns as in other overhead sports were observed, however, a different inter-articular sequence was found for the canoe polo throw with a maximal angular velocity occurring sooner for the thorax in axial rotation than for the pelvis in rotation. While the limitation of rotation of the pelvis around a vertical axis has an influence on the pelvis and trunk kinematics, it did not modify the kinematic sequence.

Long-term Reverse Total Shoulder Arthroplasty Outcomes: The Effect of the Inferior Shifting of Glenoid Component Fixation

Backgroud

The 155° Grammont reverse shoulder replacement has a long track record of success, but also a high radiographic notching rate. The increased distance between the scapular pillar and the humeral component theoretically decreases postoperative notching. The glenoid component can be shifted inferiorly relative to the glenoid; however, there also is some concern that shifting the glenoid component too far inferiorly (inferior glenoid component overhang > 3.5 mm) may compromise long-term stability of the glenoid component. This study was conducted to determine if clinical outcomes, scapular notching, and complications vary with more inferior placement of the glenoid component.

Methods

A retrospective analysis of prospectively collected data was performed in order to compare radiographic outcomes (notching rate and signs of glenoid loosening or component disassembly) and clinical outcomes (range of motion, Constant score, subjective shoulder value, and complication rate) of all patients who underwent reverse shoulder replacement with the glenosphere positioned either flush with the inferior rim of the glenoid (flush group) or with at least 3.5 mm of inferior overhang (overhang group) at a minimum follow-up of 60 months. Ninety-seven patients ultimately met the inclusion criteria, with 41 patients with flush glenoid component and 56 patients with at least 3.5 mm of inferior overhang.

Results

Average follow-up was 97.8 months. The overhang group had a lower rate of radiographic notching (37% vs. 82.5%, p < 0.05), better clinical outcomes (improvement in Constant score: +40 vs. +32, p = 0.036), and higher subjective shoulder value (79 vs. 69, p = 0.026) than the flush group. No difference in complications between groups was found.

Conclusions

In this study, at least 3.5 mm of inferior glenosphere overhang relative to the inferior rim of the glenoid was associated with the lower notching rate without negative effect on the clinical outcomes in 155° Grammont-style reverse shoulder replacement. Therefore, no increase in complications should be expected when using this surgical technique.

Clinical and radiologic outcomes of eccentric glenosphere versus concentric glenosphere in reverse shoulder arthroplasty

BACKGROUND

The use of an eccentric glenosphere (EG) has been proposed as a way to prevent scapular notching in reverse shoulder arthroplasty (RSA). The purpose of this study was to investigate whether the use of an EG decreases scapular notching compared with matched standard concentric glenosphere (CG) controls.

METHODS

A retrospective analysis was performed. This study included 49 RSAs with an EG and 49 paired RSAs with a CG with a minimum 60 months of both clinical and radiographic follow-up. Clinical and radiologic outcomes of the EG and CG groups were compared at inclusion and at the last follow-up using the paired Student t test for quantitative data and the χ² test for qualitative data. Scapular notching was graded according to the Sirveaux classification. Statistical significance was set at P < .05.

RESULTS

Notching was observed 2.7 times (95% confidence interval, 1.0-6.8 times) more often in the CG group (P = .037). The difference in notching severity between the groups was not statistically relevant; however, there was a trend toward more severe notching in the CG group (P = .059). Compared with a CG, an EG did not increase the percentage of radiolucent lines around the screws (3% vs. 1.5%, P = .62), around the post (3% vs. 1.5%, P = .62), or below the baseplate (15% vs. 7.5%, P = .18).

CONCLUSION

EGs are associated with less notching than CGs. This finding confirms that RSA with an EG is an effective procedure without specific complications at a minimum follow-up of 5 years.

The S-STARTS Test: Validation of a Composite Test for the Assessment of Readiness to Return to Sport After Shoulder Stabilization Surgery

BACKGROUND

The time elapsed since surgery is the primary criterion for allowing athletes to return to sport after shoulder stabilization surgery using the Latarjet procedure. The objective assessment of shoulder functional status through the return-to-sport continuum demands a scoring instrument that includes psychological and physical dimensions. This study aimed to statistically validate the Shoulder-SanTy Athletic Return To Sport (S-STARTS) score in patients who have undergone primary shoulder stabilization surgery.

HYPOTHESIS

The S-STARTS score fulfils the criteria for statistical validation for assessing return-to-sport readiness after shoulder stabilization surgery.

STUDY DESIGN

Diagnostic study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Fifty patients and 50 controls completed the Shoulder Instability-Return to Sport after Injury questionnaire and performed 4 physical performance tests, from which 8 outcome measures were extracted to provide a composite score, named S-STARTS, according to a scoring procedure. The statistical validation of the S-STARTS score was based on construct validity, discriminant validity, sensitivity to change, internal consistency, reliability, agreement, and feasibility.

RESULTS

The 8 components of the S-STARTS score provided additional information (0.01 ≤ |r| ≤ 0.59). The S-STARTS score exhibited good reliability (intraclass coefficient of correlation [3,k] = 0.74), no ceiling or floor effects, and high discrimination and sensitivity to change. The S-STARTS score was significantly lower in patients than in controls (13.5 ± 3.8 points vs 16.1 ± 2.7 points, respectively; P < 0.001). A significant increase was reported between 4.5 and 6.5 months postoperatively (12.8 ± 2.3 points vs 17.2 ± 2.4 points, respectively; P < 0.001).

CONCLUSIONS

The S-STARTS score meets statistical validation criteria for the assessment of shoulder functional status after shoulder stabilization surgery using the Latarjet procedure.

CLINICAL RELEVANCE

Using an S-STARTS score-based assessment to monitor an athlete's progression through the return-to-sport continuum may help clinicians and strength and conditioning coaches in return-to-sport decision-making.

Subcapularis tendon tear: A structure-based arthroscopic description

INTRODUCTION

Subscapularis (SSC) tendons differ from supraspinatus tendons, although both have similar histologic structure comprising two layers with distinct collagen fiber organization.

HYPOTHESIS

The partial/full-thickness tear classification for the supraspinatus based on tendon structure can be applied to the subscapularis tendon on objective criteria.

MATERIAL AND METHODS

The present study used 100 films of arthroscopic rotator cuff repair involving SSC lesion. Lesions were reported on 3 objective criteria: horizontal superior tendon edge visibility, lesser tuberosity bone exposure, and lateral tendon edge visibility. Combining the three distinguishes deep, superficial or interstitial partial tear versus full-thickness tear. Degree of retraction was also noted.

RESULTS

Forty-six of the 73 partial lesions involved the deep articular layer, which was often retracted, but conserving the horizontal superior tendon edge and thus misleadingly suggesting SSC integrity; 23 were interstitial, without detachment from the lesser tuberosity; 4 involved only the superficial layer. Full-thickness tears were always retracted, with loss of horizontal superior tendon edge, visibility of the lateral tendon edge and presence of comma sign. Inter- and intra-observer reproducibility was satisfactory.

DISCUSSION - CONCLUSION

Like in superior cuff tear, a structure-based classification can be made of SSC lesions on objective criteria.

LEVEL OF EVIDENCE

IV.

The Invisible MGHL Test: Diagnostic Value and Benefits for the Repair of Retracted Subscapularis Tears

BACKGROUND

Some full-thickness subscapularis tendon tears and partial tears of the deep layer are difficult to characterize, leading to misdiagnosis.

PURPOSE

To evaluate the association between displacement of the middle glenohumeral ligament (MGHL) and retracted tears of the subscapularis tendon as a possible test to improve diagnosis.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Videos (N = 100) recorded during arthroscopic rotator cuff repair involving a torn subscapularis tendon were analyzed retrospectively to assess the association between the MGHL test (nonvisibility of the MGHL) and other objective anatomic criteria. The invisible MGHL test was defined as positive if the MGHL was initially nonvisible in the beach-chair position and appeared only when the subscapularis tendon was pulled back into position by using a 30° arthroscope from the standard posterior portal. The parameters considered during the initial exploration were (1) visibility of the horizontal part of the subscapularis tendon; (2) visibility of the MGHL in its usual position, crossing the superior border of the subscapularis tendon; (3) exposure of the lateral border of the subscapularis tendon (full-thickness retracted tear); and (4) complete or partial exposure of the lesser tuberosity of the humerus. Tendon retraction was evaluated in 3 stages according to the Patte classification.

RESULTS

The invisible MGHL test result was positive in 45% of cases. It was positive in 6% of cases (2 of 31) when there was no subscapularis tendon retraction and in 62% of cases (43 of 69) when there was partial or complete retraction (P < .001). The invisible MGHL test was significantly associated with the width of the tear (P < .001) and exposure of the lateral border of the subscapularis tendon (full-thickness retracted tear, P = .0002). After repair, the MGHL was visible in its anatomic position in 96% of cases.

CONCLUSION

A positive invisible MGHL test is an alternative indication of subscapularis tendon retraction, and the relocation of the MGHL can also be used after repair to assess the proper anatomic repositioning of the subscapularis tendon.

Midterm clinical and radiologic results of reverse shoulder arthroplasty with an eccentric glenosphere

BACKGROUND

An eccentric glenosphere (EG) has been proposed as a way of preventing scapular notching after reverse shoulder arthroplasty (RSA). Our aim was to report the midterm clinical and radiographic results of EG after RSA. A number of the patients described here were included in a previous study with short-term follow-up. The current retrospective study gave us the opportunity to follow many of these patients for a longer period of time.

METHODS

A retrospective analysis of prospectively collected data was conducted. Statistical significance was set at P < .001. Forty-nine RSAs with an EG and at least 60 months of follow-up were included. Range of motion (ROM), Constant scores (CSs), and Subjective Shoulder Value (SSV) were assessed. Scapular notching was graded according to the Sirveaux classification.

RESULTS

At the last follow-up, the mean improvement in active elevation (ROM) was 46° and the mean CS increased by nearly 31 points (both groups P < .001). The final SSV was 70%. Twenty-one patients (43%) had scapular notching, but in two-thirds of patients it was low-grade.

CONCLUSION

The use of an EG provided excellent clinical outcomes that persisted with midterm follow-up. The rate of notching was lower than in other studies with EGs, but further studies are required to confirm this. An EG was safe and there were no issues with baseplate loosening or failure.

The Middle Glenohumeral Ligament Test for the Diagnosis of Subscapularis Lesions

Arthroscopy has improved the diagnosis of subscapularis tendon lesions, and the outcomes of arthroscopic repair are satisfactory. Nonetheless, the diagnosis of some partial- and full-thickness subscapularis tears remains challenging. The middle glenohumeral ligament inserts distally into the articular surface of the subscapularis tendon and can be displaced when the subscapularis tendon is torn with retraction. This article describes the middle glenohumeral ligament test, which allows retracted lesions of the subscapularis tendon to be detected even if the superior edge is visible and normally placed. In addition, it allows control of the subscapularis tendon repair.

Three-dimensional characterization of the anteverted glenoid (type D) in primary glenohumeral osteoarthritis

BACKGROUND

The Walch classification describes glenoid morphology in primary arthritis. As knowledge grows, several modifications to the classification have been proposed. The type D, a recent modification, was defined as an anteverted glenoid with or without anterior subluxation. Literature on the anteverted glenoid in primary osteoarthritis is limited. The purpose of this study, therefore, was to analyze the anatomic characteristics of the type D glenoid on radiographs and computed tomography (CT).

METHODS

The shoulder arthroplasty databases from 3 institutions were examined to identify patients with primary glenohumeral osteoarthritis and glenoid anteversion (≥5°), with or without anterior subluxation. The type D study cohort consisted of 18 patients (3% of the osteoarthritis cohort) and was a mean of 70 years old, with 11 women and 7 men. All radiographs were reviewed, and computed tomography Digital Imaging and Communications in Medicine (National Electrical Manufacturers Association, Rosslyn, VA, USA) data were analyzed on validated 3-dimensional imaging software. Rotator cuff fatty infiltration, glenoid measurements (anteversion and inclination), and humeral head subluxation according to the scapular plane were determined.

RESULTS

In the study cohort, the mean glenoid anteversion was 12° (range, 5°-24°), the mean inclination was 0°, and the mean anterior subluxation was 38% (range, 6%-56%). Eight patients (44%) had a biconcave glenoid with a posterosuperiorly positioned paleoglenoid and an anteroinferiorly positioned neoglenoid, and 10 patients had a monoconcave glenoid. Fatty infiltration of the rotator cuff muscles never exceeded Goutallier stage 2.

CONCLUSION

The type D glenoid is an addition to the original Walch classification and is characterized by glenoid anteversion (≥5°), anteroinferior humeral head subluxation, and absence of severe subscapularis fatty infiltration.

Arthroscopic anatomy of the middle glenohumeral ligament

PURPOSE

The middle glenohumeral ligament (MGHL) has seldom been studied and its function is unknown. The aim of this study was to describe its anatomical presentations.

METHODS

A prospective study was conducted of MGHL anatomy in 107 arthroscopies, with a description of its shape and superior and inferior insertion in the articular surface of the subscapularis tendon. The MGHL was investigated dynamically during internal rotation of the glenohumeral joint.

RESULTS

Sixty-three percent (68/107) of the MGHLs were found to be leaf-like, and 27% (28/107) cord-like, 5.5% (6/107) vestigial, and 2% (2/107) had several strands. The MGHL was absent for 2% of patients (2/107). The inferior insertion point of the MGHL was lateral, masked by the humeral head, in 34% of cases (36/105), intermediate, in front of the glenohumeral joint line, in 57% of cases (60/105), and medial, in front of the labrum, in 9% of cases (9/105). During internal rotation, 46% (48/105) of the MGHLs were observed to retract medially, the subscapularis tendon moving away from the anterior glenoid rim, while 54% (57/105) remained visible in front of the glenohumeral joint and came into contact with the articular surface of the subscapularis tendon.

CONCLUSIONS

The MGHL has many anatomical variations.