BACKGROUND: Subscapularis tendon (SSc) dysfunction following total shoulder arthroplasty (TSA) results in poor functional outcomes. There have been numerous SSc repair constructs tested biomechanically and clinically, however, none has been demonstrated as superior. Newer techniques and implants have emerged, but have not been fully tested.
OBJECTIVE: We hypothesized that the unicortical button (UB) fixation will provide significantly improved restoration of the anatomic footprint and biomechanical properties when compared to transosseous (TO) repair of the SSc.
METHODS: A digital footprint of SSc humeral insertion was obtained in 6 pairs of fresh-frozen cadaveric shoulders using a three-dimensional (3-D) digitizer. A complete SSc tear was created, and each pair of shoulders was randomized to either SSc repair with UB or TO repair. Each specimen underwent a cyclic loading protocol followed by pull-to-failure. The failure load, elongation at failure, gapping failure, number of cycles until failure, the load at key gapping points (1 mm, 3 mm, 5 mm, and 10 mm) and the failure mode were recorded using high-resolution video recording. 3-D surfaces of the insertion footprint and repair site were obtained, and surface areas were calculated using a custom MATLAB script and laser scanner. Paired t-tests were conducted to compare differences between two repair groups.
RESULTS: Failure load was significantly higher in the UB group (382.4 N ± 56.5 N) than in the TO group (253.6 N ± 103.4 N, p=0.005). TO repair provided higher gapping at failure (28.8 mm ± 8.2 mm) than UB repair (10.4 mm ± 6.8 mm, p=0.0017). UB repair had significantly higher load at the 1-mm, 5-mm, and 10-mm gapping compared with TO repair with p=0.042, p=0.033, and p=0.0076, respectively. There were no significant differences between elongation failure, the difference in footprint area from native to repair states, or the percentage of restored footprint area between groups. (p=0.26, p=0.18 and p=0.21 respectively) CONCLUSION: The UB fixation showed a significantly lower gap at failure, higher failure load and number of cycles until failure, and higher gap loads compared with the traditional TO repair for SSc. Although more clinical research is necessary, the UB fixation that utilizes cortical bone presents promising results.

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 suggest 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 mid-term radiographic loosening in aTSA.
METHODS: The study cohort was identified via an institutional repository of 337 preoperative CT scans from 2010-2017. 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 non-augmented 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=0.26), sex (19 [68%] vs. 19 [68%] male, p=1.0), or follow-up (6.1 vs. 6.4 years, p=0.59). Biplanar deformities had greater inclination (14.5˚ versus 5.3˚, p<0.001), retroversion (30.0˚ versus 25.6˚, p=0.01) and humeral subluxation (86.3% versus 82.1%, p=0.03). Biplanar patients had greater postoperative implant superior inclination (5.9 [4.6] vs. 3.0 [3.6] degrees, p=0.01) but similar rate of complete seating 24 [86%] vs. 24 [86%] p=1.0). At final follow-up, biplanar subjects had higher Lazarus radiolucent scores (2.4 [1.7] vs. 1.6 [1.1], p=0.03) and higher proportion of patients with glenoid radiolucency (19 [68%] vs. 11 [39%], p=0.03). No difference in complete component seating (86% versus 86%, p=0.47) or initial radiolucency grade (0.21 versus 0.29, p=0.55) on immediate postop radiographs. Biplanar patients demonstrated a greater amount of posterior subluxation at immediate postop(3.5% [1.3%] versus 1.8% [0.6%]; p=0.03) and final follow-up (7.6% [2.8%] versus 4.0% [1.8%]; p=0.04). At final radiographic follow-up, biplanar subjects had higher Lazarus radiolucent scores (2.4 [1.7] vs. 1.6 [1.1], p=0.03; ICC=0.82). Bivariate regression analysis demonstrated biplanar deformity was the only significant predictor (OR 3.3, p=0.04) of glenoid radiolucency.
CONCLUSIONS: Biplanar glenoid deformity resulted in time-zero glenoid implant superior inclination and increased mid-term radiographic loosening and posterior subluxation. Attention to glenoid inclination is important for successful anatomical glenoid reconstruction. Future research is warranted to understand the long-term implications of these findings and impact of utilizing augmented implants or reverse shoulder arthroplasty to manage biplanar deformities.

暂无摘要。

A lesser tuberosity osteotomy (LTO) is commonly performed during total shoulder arthroplasty to access the glenohumeral joint. Healing of the LTO is critical to optimizing the outcome of the procedure and is enhanced by a repair that provides stability and compression across the osteotomy site. The purpose of this article is to describe a technique that uses a tensionable suture construct to repair the LTO during anatomic total shoulder arthroplasty using a stemless humeral component. The technique involves passing a row of high-tensile sutures through bone tunnels lateral to the osteotomy site (transosseous sutures) and another row of sutures through the humeral implant (implant sutures). One limb of each bone tunnel suture is then tied to its corresponding limb of implant suture and the remaining free strands of the tied sutures are manually tensioned and tied to each other. This technique is an efficient and reproducible method for creating compression and stability across the osteotomy site that facilitates bony healing.

BACKGROUND: In patients with glenohumeral osteoarthritis and posteriorly eccentric wear patterns, the early to midterm results of total shoulder arthroplasty (TSA) using conservative glenoid reaming with no attempt at version correction have been favorable at early follow-up. The purpose of this study is to compare the clinical and radiographic outcomes of TSA using this technique for patients with and without eccentric wear patterns at a minimum 5-year follow-up.
METHODS: Patients who underwent TSA with minimum 5-year follow-up were identified from an institutional registry. Preoperative and postoperative radiographs were used to determine humeroglenoid alignment (HGA-AP), humeroscapular alignment (HSA-AP), version, Walch classification, and glenoid component seating. The outcome measures were the Simple Shoulder Test (SST), glenoid component radiolucencies, and the occurrence of complications or revisions.
RESULTS: Two hundred ten patients were included in the study, of which 98 (47%) had posteriorly decentered humeral heads and 108 (51%) had centered humeral heads. There were 77 shoulders with Walch type A glenoids and 122 with Walch type B glenoids. At a mean 8-year follow-up, the final SST score, change in SST score, and percentage of maximal improvement was not correlated with pre- and postoperative humeral head centering, Walch classification, or glenoid version. There were no preoperative predictors of a low final SST score. Two patients (1%) underwent open reoperations during the study period. In patients with Walch B1 and B2 glenoids (n = 110), there were no differences in outcome measures between patients with postoperative retroversion of more and less than 15°. Although 15 of 51 patients (29%) with minimum 5-year radiographs had glenoid radioluciences, these radiographic findings were not associated with inferior clinical outcomes. On multivariable analysis, glenoid component radiolucencies were most strongly associated with incomplete component seating (OR 3.3, P = .082).
CONCLUSIONS: The results of TSA with conservative glenoid reaming without attempt at version correction are favorable at a minimum 5-year, and mean 8-year, follow-up. There were no differences in clinical and radiographic outcomes between patients with eccentric and concentric wear patterns. Incomplete glenoid component seating was the greatest predictor of glenoid component radiolucency, but these radiolucencies were not associated with inferior clinical outcomes.

BACKGROUND: Preoperative 3-dimensional (3D) computed tomography (CT)-based planning for anatomic total shoulder arthroplasty (TSA) has grown in popularity in the past decade with the primary focus on the glenoid. Little research has evaluated if humeral planning has any effect on the surgical execution of the humeral cut or the positioning of the prosthesis.
METHODS: Three surgeons performed a prospective study using 3D-printed humeri printed from CTs of existing patients, which were chosen to be -3, -1, 0, 1, and 3 standard deviations of all patients in a large database. A novel 3D printing process was used to 3D print not only the humerus but also all 4 rotator cuff tendons. For each surgical procedure, the printed humerus was mounted inside a silicone shoulder, with printed musculature and skin, and with tensions similar to human tissue requiring standard retraction and instruments to expose the humerus. Three phases of the study were designed. In phase 1, humeral neck cuts were performed on all specimens without any preoperative humeral planning; in phase 2, 3D planning was performed, and the cuts and implant selection were repeated; in phase 3, a neck-shaft angle (NSA) guide and digital calipers were used to measure humeral osteotomy thickness to aid in the desired humeral cut. All humeri were digitized. The difference between the prosthetic center of rotation (COR) and ideal COR was calculated. The percentage of patients with a varus NSA was calculated for each phase. The difference in planned and actual cut thickness was also compared.
RESULTS: For both 3D change in COR and medial to lateral change in COR, use of preoperative planning alone and with standard transfer instrumentation resulted in a significantly more anatomic restoration of ideal COR. The deviations from planned cut thickness decreased with each phase: phase 1: 2.6 ± 1.9 mm, phase 2: 2.0 ± 1.3 mm, phase 3: 1.4 ± 0.9 mm (P = .041 for phase 3 vs. phase 1). For NSA, in phase 1, 7 of 15 (47%) cases were in varus; in phase 2, 5 of 15 (33%) were in varus; and in phase 3, 1 of 15 (7%) cases was in varus (P = .013 for phase 3 vs. phase 1).
CONCLUSIONS: Use of preoperative 3D humeral planning for stemless anatomic TSA improved prosthetic humeral COR, whether performed with or without standard transfer instrumentation. The use of an NSA cut guide and calipers to measure cut thickness significantly reduced the percentage of varus humeral cuts and deviation from planned cut thickness.

BACKGROUND: Walch B2 glenoids can present a challenge to shoulder arthroplasty surgeons. Short-term studies have demonstrated that corrective reaming to 10° of retroversion in anatomic total shoulder arthroplasty (aTSA) can result in good outcomes; however, there is little data reporting the long-term outcomes in this cohort. B2 glenoids treated with high-side reaming present a theoretical risk of early glenoid component failure as one may ream into the subchondral bone. This study aimed to demonstrate that (1) B2 glenoids treated with corrective reaming have durable results and (2) offer similar results to Walch A1/2 in long-term follow-up.
METHODS: Patients who underwent aTSA by a single surgeon (E.L.F.) were identified from a shoulder arthroplasty registry. Inclusion criteria included Walch A1, A2, or B2 glenoid; a diagnosis of primary shoulder osteoarthritis; and a minimum radiographic and clinical follow-up of 5 years. Forty-three patients with B2 glenoids were compared to a cohort of 42 patients with A1 or A2 glenoids. Preoperative computed tomography (CT) and radiographs were used to assess deformity, glenoid version, and posterior subluxation of the humeral head. Postoperatively, patients were assessed with radiographs and patient-reported outcome measures including American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, Simple Shoulder Test (SST) score, and visual analog scale (VAS).
RESULTS: Eighty-five shoulders (82 patients, 42 B2 and 43 A1/A2 glenoids) with an average follow-up of 9.4 years were included. In the B2 cohort, the average retroversion was 21.1° and posterior subluxation was 69.4% compared with 10.6° (P < .001) and 57.5% (P < .001), respectively, in the A1 or A2 cohort. The cohort demographics were similar except for male sex (B2 69.8% vs. A1 or A2 37.2%, P = .008). There was no difference between the cohorts in their improvement in ASES (P = .807), SST (P = .586), and VAS (P = .930) scores. There was no difference in lateral humeral offset (P = .889) or acromial humeral interval (P = .468) between initial postoperative and final follow-up visits. Survivorship for B2 glenoids was 97.6%, 94.1%, and 73.3% at 5, 10, and 15 years, respectively, compared with 97.6%, 91.9%, and 83.5% in type A glenoids. The revision rate was similar between the 2 groups (P = .432). Lazarus score (P = .682) and rates of humeral radiolucency (P = .366) and humeral osteolysis (P = .194) were similar between the 2 cohorts at final follow-up.
CONCLUSIONS: Asymmetric reaming of patients with B2 glenoids is a reliable method of glenoid preparation with excellent mid- to long-term clinical results, patient-reported outcomes, and low revision rates similar to their A1 and A2 counterparts.

BACKGROUND: The stemmed anatomic total shoulder arthroplasty is the gold standard in the treatment of glenohumeral osteoarthritis. However, the use of stemless total shoulder arthroplasties has increased in recent years. The number of revision procedures are relatively low, and therefore it has been recommended that national joint replacement registries should collaborate when comparing revision rates. Therefore, we aimed to compare the revision rates of stemmed and stemless TSA used for the diagnosis of glenohumeral osteoarthritis using data from both the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and the Danish Shoulder Arthroplasty Registry (DSR).
METHODS: We included all patients who were registered in the AOANJRR and the DSR from January 1, 2012, to December 2021 with an anatomic total shoulder arthroplasty used for osteoarthritis. Revision for any reason was used as the primary outcome. We used the Kaplan-Meier method to illustrate the cumulative revision rates and a multivariate cox regression model to calculate the hazard ratios. All analyses were performed separately for data from AOANJRR and DSR, and the results were then reported using a qualitative approach.
RESULTS: A total of 13,066 arthroplasties from AOANJRR and 2882 arthroplasties from DSR were included. The hazard ratio for revision of stemmed TSA with stemless TSA as reference, adjusted for age and gender, was 1.67 (95% confidence interval [CI] 1.34-2.09, P < .001) in AOANJRR and 0.57 (95% CI 0.36-0.89, P = .014) in DSR. When including glenoid type and fixation, surface bearing (only in AOANJRR), and hospital volume in the cox regression model, the hazard ratio for revision of stemmed TSA compared to stemless TSA was 1.22 (95% CI 0.85-1.75, P = .286) in AOANJRR and 1.50 (95% CI 0.91-2.45, P = .109) in DSR. The adjusted hazard ratio for revision of total shoulder arthroplasties with metal-backed glenoid components compared to all-polyethylene glenoid components was 2.54 (95% CI 1.70-3.79, P < .001) in AOANJRR and 4.1 (95% CI 1.92-8.58, P < .001) in DSR.
CONCLUSIONS: Based on data from 2 national shoulder arthroplasty registries, we found no significant difference in risk of revision between stemmed and stemless total shoulder arthroplasties after adjusting for the type of glenoid component. We advocate that metal-backed glenoid components should be used with caution and not on a routine basis.

Background: Despite the importance of the deltoid to shoulder biomechanics, very few studies have quantified the three-dimensional shape, size, or quality of the deltoid muscle, and no studies have correlated these measurements to clinical outcomes after anatomic (aTSA) and/or reverse (rTSA) total shoulder arthroplasty in any statistically/scientifically relevant manner. Methods: Preoperative computer tomography (CT) images from 1057 patients (585 female, 469 male; 799 primary rTSA and 258 primary aTSA) of a single platform shoulder arthroplasty prosthesis (Equinoxe; Exactech, Inc., Gainesville, FL) were analyzed in this study. A machine learning (ML) framework was used to segment the deltoid muscle for 1057 patients and quantify 15 different muscle characteristics, including volumetric (size, shape, etc.) and intensity-based Hounsfield (HU) measurements. These deltoid measurements were correlated to postoperative clinical outcomes and utilized as inputs to train/test ML algorithms used to predict postoperative outcomes at multiple postoperative timepoints (1 year, 2-3 years, and 3-5 years) for aTSA and rTSA. Results: Numerous deltoid muscle measurements were demonstrated to significantly vary with age, gender, prosthesis type, and CT image kernel; notably, normalized deltoid volume and deltoid fatty infiltration were demonstrated to be relevant to preoperative and postoperative clinical outcomes after aTSA and rTSA. Incorporating deltoid image data into the ML models improved clinical outcome prediction accuracy relative to ML algorithms without image data, particularly for the prediction of abduction and forward elevation after aTSA and rTSA. Analyzing ML feature importance facilitated rank-ordering of the deltoid image measurements relevant to aTSA and rTSA clinical outcomes. Specifically, we identified that deltoid shape flatness, normalized deltoid volume, deltoid voxel skewness, and deltoid shape sphericity were the most predictive image-based features used to predict clinical outcomes after aTSA and rTSA. Many of these deltoid measurements were found to be more predictive of aTSA and rTSA postoperative outcomes than patient demographic data, comorbidity data, and diagnosis data. Conclusions: While future work is required to further refine the ML models, which include additional shoulder muscles, like the rotator cuff, our results show promise that the developed ML framework can be used to evolve traditional CT-based preoperative planning software into an evidence-based ML clinical decision support tool.

BACKGROUND: Clinical significance, as opposed to statistical significance, has increasingly been utilized to evaluate outcomes after total shoulder arthroplasty (TSA). The purpose of this study was to identify thresholds of the minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient acceptable symptomatic state (PASS) for TSA outcome metrics and determine if these thresholds are influenced by prosthesis type (anatomic or reverse TSA), sex, or preoperative diagnosis.
METHODS: A prospectively collected international multicenter database inclusive of 38 surgeons was queried for patients receiving a primary aTSA or rTSA between 2003 and 2021. Prospectively, outcome metrics including ASES, shoulder function score (SFS), SST, UCLA, Constant, VAS Pain, shoulder arthroplasty smart (SAS) score, forward flexion, abduction, external rotation, and internal rotation was recorded preoperatively and at each follow-up. A patient satisfaction question was administered at each follow-up. Anchor-based MCID, SCB, and PASS were calculated as defined previously overall and according to implant type, preoperative diagnosis, and sex. The percentage of patients achieving thresholds was also quantified.
RESULTS: A total of 5851 total shoulder arthroplasties (TSAs) including aTSA (n = 2236) and rTSA (n = 3615) were included in the study cohort. The following were identified as MCID thresholds for the overall (aTSA + rTSA irrespective of diagnosis or sex) cohort: VAS Pain (-1.5), SFS (1.2), SST (2.1), Constant (7.2), ASES (13.9), UCLA (8.2), SPADI (-21.5), and SAS (7.3), Abduction (13°), Forward elevation (16°), External rotation (4°), Internal rotation score (0.2). SCB thresholds for the overall cohort were: VAS Pain (-3.3), SFS (2.9), SST 3.8), Constant (18.9), ASES (33.1), UCLA (12.3), SPADI (-44.7), and SAS (18.2), Abduction (30°), Forward elevation (31°), External rotation (12°), Internal rotation score (0.9). PASS thresholds for the overall cohort were: VAS Pain (0.8), SFS (7.3), SST (9.2), Constant (64.2), ASES (79.5), UCLA (29.5), SPADI (24.7), and SAS (72.5), Abduction (104°), Forward elevation (130°), External rotation (30°), Internal rotation score (3.2). MCID, SCB, and PASS thresholds varied depending on preoperative diagnosis and sex.
CONCLUSIONS: MCID, SCB, and PASS thresholds vary depending on implant type, preoperative diagnosis, and sex. A comprehensive understanding of these differences as well as identification of clinically relevant thresholds for legacy and novel metrics is essential to assist surgeons in evaluating their patient\'s outcomes, interpreting the literature, and counseling their patients preoperatively regarding expectations for improvement. Given that PASS thresholds are fragile and vary greatly depending on cohort variability, caution should be exercised in conflating them across different studies.