Three-dimensional computed tomography analysis of pathologic correction in total shoulder arthroplasty based on severity of preoperative pathology

BACKGROUND

The purpose of this study was to quantify correction of glenoid deformity and humeral head alignment in anatomic total shoulder arthroplasty as a function of preoperative pathology (modified Walch classification) and glenoid implant type in a clinical cohort using 3-dimensional computed tomography (CT) analysis.

METHODS

Patients undergoing anatomic total shoulder arthroplasty with a standard glenoid (SG) (n = 110) or posteriorly stepped augmented glenoid (AG) (n = 62) component were evaluated with a preoperative CT scan and a postoperative CT scan within 3 months of surgery. Glenoid version, inclination, and medial-lateral (ML) joint line position, as well as humeral head alignment, were assessed on both CT scans, with preoperative-to-postoperative changes analyzed relative to pathology and premorbid anatomy based on the modified Walch classification and glenoid implant type.

RESULTS

On average, correction to the premorbid ML joint line position was significantly less in type A2 glenoids than in type A1 glenoids (-2.3 ± 2.1 mm vs. 1.1 ± 0.9 mm, P < .001). Correction to premorbid version was not different between type B2 glenoids with AG components and type A1 glenoids with SG components (-1.7° ± 6.6° vs. -1.0° ± 4.0°, P = .57), and the premorbid ML joint line position was restored on average in both groups (0.3 ± 1.6 mm vs. 1.1 ± 0.9 mm, P = .006). Correction to premorbid version was not different between type B3 glenoids with AG components and type A1 glenoids with SG components (-0.6° ± 5.1° vs. -1.0° ± 4.0°, P = .72), but correction relative to the premorbid ML joint line position was significantly less in type B3 glenoids with AG components than in type A1 glenoids with SG components (-2.2 ± 2.1 mm vs. 1.1 ± 0.9 mm, P < .001). Postoperative humeral glenoid alignment was not different in any group comparisons.

DISCUSSION

In cases with posterior glenoid bone loss and retroversion (type B2 or B3 glenoids), an AG component can better correct retroversion and the glenoid ML joint line position compared with an SG component, with correction to premorbid version comparable to a type A1 glenoid with an SG component. However, restoration of the premorbid ML joint line position may not always be possible with SG or AG components in cases with more advanced central glenoid bone loss (type A2 or B3 glenoids). Further follow-up is needed to determine the clinical consequences of these findings.

Editorial Commentary: Are Serum Inflammatory Markers Useful Diagnostic Tools in the Shoulder?

Serum inflammatory markers are commonly used to evaluate for the presence of surgical-site infection or periprosthetic joint infections following orthopaedic surgery. However, data on the utility of these tests following shoulder surgery are more limited. Worse diagnostic performance is seen in the shoulder when compared with use of these tests in the evaluation of hip and knee infections, likely due to the low virulence of the commonly cultured shoulder organisms, and the normalization of these serum markers following shoulder surgery is less well defined when compared with the hip and knee literature. A better understanding of the behavior of these serum inflammatory markers in the shoulder may enhance the utility of these tests in the diagnosis and management of infection following elective shoulder surgery.

What Are the Predictors of Poor Patient-Reported Outcomes After Shoulder Instability Surgery?

Background:

Prospectively collected responses to Patient Acceptable Symptom State (PASS) questions after shoulder instability surgery are limited. Responses to these outcome measures are imperative to understanding their clinical utility.

Purpose/Hypothesis:

The purpose of this study was to evaluate which factors predict unfavorable patient-reported outcomes after shoulder instability surgery, including “no” to the PASS question. We hypothesized that poor outcomes would be associated with male adolescents, bone loss, combined labral tears, and articular cartilage injuries.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

Patients aged ≥13 years undergoing shoulder instability surgery were included in point-of-care data collection at a single institution across 12 surgeons between 2015 and 2017. Patients with anterior-inferior labral tears were included, and those with previous ipsilateral shoulder surgery were excluded. Demographics, American Shoulder and Elbow Surgeons (ASES) and Single Assessment Numeric Evaluation (SANE) scores, and surgical findings were obtained at baseline. ASES and SANE scores, PASS responses, and early revision surgery rates were obtained at a minimum of 1 year after the surgical intervention. Regression analyses were performed.

Results:

A total of 234 patients met inclusion criteria, of which 176 completed follow-up responses (75.2%). Nonresponders had a younger age, greater frequency of glenoid bone loss, fewer combined tears, and more articular cartilage injuries (P < .05). Responders’ mean age was 25.1 years, and 22.2% were female. Early revision surgery occurred in 3.4% of these patients, and 76.1% responded yes to the PASS question. A yes response correlated with a mean 25-point improvement in the ASES score and a 40-point improvement in the SANE score. On multivariate analysis, combined labral tears (anterior-inferior plus superior or posterior tears) were associated with greater odds of responding no to the PASS question, while both combined tears and injured capsules were associated with lower ASES and SANE scores (P < .05). Sex, bone loss, and grade 3 to 4 articular cartilage injuries were not associated with variations on any patient-reported outcome measure.

Conclusion:

Patients largely approved of their symptom state at ≥1 year after shoulder instability surgery. A response of yes to the PASS question was given by 76.1% of patients and was correlated with clinically and statistically significant improvements in ASES and SANE scores. Combined labral tears and injured capsules were negative prognosticators across patient-reported outcome measures, whereas sex, bone loss, and cartilage injuries were not.

The value of artificial neural networks for predicting length of stay, discharge disposition, and inpatient costs after anatomic and reverse shoulder arthroplasty

HYPOTHESIS/PURPOSE

The objective is to develop and validate an artificial intelligence model, specifically an artificial neural network (ANN), to predict length of stay (LOS), discharge disposition, and inpatient charges for primary anatomic total (aTSA), reverse total (rTSA), and hemi- (HSA) shoulder arthroplasty to establish internal validity in predicting patient-specific value metrics.

METHODS

Using data from the National Inpatient Sample between 2003 and 2014, 4 different ANN models to predict LOS, discharge disposition, and inpatient costs using 39 preoperative variables were developed based on diagnosis and arthroplasty type: primary chronic/degenerative aTSA, primary chronic/degenerative rTSA, primary traumatic/acute rTSA, and primary acute/traumatic HSA. Models were also combined into diagnosis type only. Outcome metrics included accuracy and area under the curve (AUC) for a receiver operating characteristic curve.

RESULTS

A total of 111,147 patients undergoing primary shoulder replacement were included. The machine learning algorithm predicting the overall chronic/degenerative conditions model (aTSA, rTSA) achieved accuracies of 76.5%, 91.8%, and 73.1% for total cost, LOS, and disposition, respectively; AUCs were 0.75, 0.89, and 0.77 for total cost, LOS, and disposition, respectively. The overall acute/traumatic conditions model (rTSA, HSA) had accuracies of 70.3%, 79.1%, and 72.0% and AUCs of 0.72, 0.78, and 0.79 for total cost, LOS, and discharge disposition, respectively.

CONCLUSION

Our ANN demonstrated fair to good accuracy and reliability for predicting inpatient cost, LOS, and discharge disposition in shoulder arthroplasty for both chronic/degenerative and acute/traumatic conditions. Machine learning has the potential to preoperatively predict costs, LOS, and disposition using patient-specific data for expectation management between health care providers, patients, and payers.

The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part II

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this study was to provide a focused, updated systematic review for each of the most common complications of RSA by limiting each search to publications after 2010. In this part II, the following were examined: (1) instability, (2) humerus/glenoid fracture, (3) acromial/scapular spine fractures (AF/SSF), and (4) problems/miscellaneous.

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Overall, 137 studies for instability, 94 for humerus/glenoid fracture, 120 for AF/SSF, and 74 for problems/miscellaneous were included in each review, respectively. Univariate analysis was performed with chi-square and Fisher exact tests.

Results

The Grammont design had a higher instability rate vs. all other designs combined (4.0%, 1.3%; P < .001), and the onlay humerus design had a lower rate than the lateralized glenoid design (0.9%, 2.0%; P = .02). The rate for intraoperative humerus fracture was 1.8%; intraoperative glenoid fracture, 0.3%; postoperative humerus fracture, 1.2%; and postoperative glenoid fracture, 0.1%. The rate of AF/SSF was 2.6% (371/14235). The rate for complex regional pain syndrome was 0.4%; deltoid injury, 0.1%; hematoma, 0.3%; and heterotopic ossification, 0.8%.

Conclusions

Focused systematic reviews of recent literature with a large volume of shoulders demonstrate that using non-Grammont modern prosthesis designs, complications including instability, intraoperative humerus and glenoid fractures, and hematoma are significantly reduced compared with previous studies. As the indications continue to expand for RSA, it is imperative to accurately track the rate and types of complications in order to justify its cost and increased indications.

The modern reverse shoulder arthroplasty and an updated systematic review for each complication: part I

Background

Globally, reverse shoulder arthroplasty (RSA) has moved away from the Grammont design to modern prosthesis designs. The purpose of this 2-part study was to systematically review each of the most common complications of RSA, limiting each search to publications in 2010 or later. In this part (part I), we examined (1) scapular notching (SN), (2) periprosthetic infection (PJI), (3) mechanical failure (glenoid or humeral component), and (4) neurologic injury (NI).

Methods

Four separate PubMed database searches were performed following Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Overall, 113 studies on SN, 62 on PJI, 34 on mechanical failure, and 48 on NI were included in our reviews. Univariate analysis was performed with the χ² or Fisher exact test.

Results

The Grammont design had a higher SN rate vs. all other designs combined (42.5% vs. 12.3%, P < .001). The onlay humeral design had a lower rate than the lateralized glenoid design (10.5% vs. 14.8%, P < .001). The PJI rate was 2.4% for primary RSA and 2.6% for revision RSA. The incidence of glenoid and humeral component loosening was 2.3% and 1.4%, respectively. The Grammont design had an increased NI rate vs. all other designs combined (0.9% vs. 0.1%, P = .04).

Conclusions

Focused systematic reviews of the recent literature with a large volume of RSAs demonstrate that with the use of non-Grammont modern prosthesis designs, complications including SN, PJI, glenoid component loosening, and NI are significantly reduced compared with previous studies. As the indications for RSA continue to expand, it is imperative to accurately track the rates and types of complications to justify its cost and increased indications.

Associations of preoperative patient mental health status and sociodemographic and clinical characteristics with baseline pain, function, and satisfaction in patients undergoing primary shoulder arthroplasty

HYPOTHESIS AND BACKGROUND

Shoulder pain and dysfunction are common indications for shoulder arthroplasty, yet the factors that are associated with these symptoms are not fully understood. This study aimed to investigate the associations of patient and disease-specific factors with preoperative patient-reported outcome measures (PROMs) in patients undergoing primary shoulder arthroplasty. We hypothesized that worse mental health status assessed by the Veterans RAND 12-Item Health Survey (VR-12) mental component score (MCS), glenoid bone loss, and increasing rotator cuff tear severity would be associated with lower values for the preoperative total Penn Shoulder Score (PSS) and its pain, function, and satisfaction subscores.

METHODS

We prospectively identified 12 patient factors and 4 disease-specific factors as possible statistical predictors of preoperative PROMs in patients undergoing primary shoulder arthroplasty at a single institution over a 3-year period. Multivariable statistical modeling and Akaike information criterion comparisons were used to investigate the unique associations with, and relative importance of, these factors in accounting for variation in the preoperative PSS and its subscores.

RESULTS

A total of 788 cases performed by 12 surgeons met the inclusion criteria, with a preoperative median total PSS of 31 points (pain, 10 points; function, 18 points; and satisfaction, 1 point). As hypothesized, a lower VR-12 MCS was associated with lower preoperative PSS pain, function, and total scores, but patients with intact status or small to medium rotator cuff tears had modestly lower PSS pain subscores (ie, more pain) than patients with large to massive superior-posterior rotator cuff tears. Glenoid bone loss was not associated with the preoperative PSS. Female sex and fewer years of education (for all 4 outcomes), lower VR-12 MCS and preoperative opioid use (for all outcomes but satisfaction), and rotator cuff tear severity (for pain only) were the factors most prominently associated with preoperative PROMs.

CONCLUSION

In addition to mental health status and rotator cuff tear status, patient sex, years of education, and preoperative opioid use were most prominently associated with preoperative PROMs in patients undergoing shoulder arthroplasty. Further studies are needed to investigate whether these factors will also predict postoperative PROMs.

Influence of reverse total shoulder arthroplasty baseplate design on torque and compression relationship

Background

A linear relationship between baseplate insertion torque and compression force in reverse shoulder arthroplasty (RSA) baseplates with central screw design has been recently established. In this study, we evaluated 3 different baseplate designs and their influence on the torque-compression relationship.

Methods

Three different RSA baseplate designs were evaluated through biomechanical testing using a glenoid vault, bone surrogate model. A digital torque gauge was used to measure insertion torque applied to the baseplate, whereas compression data were collected continuously from a load cell. Additionally, 2 predictive models were developed to predict the compression forces of each baseplate design at varying levels of torque.

Results

A linear relationship was found between baseplate compression and insertion torque for all 3 baseplate designs. Both the monoblock and 2-piece locking designs achieved the goal torque of 6.8 Nm, whereas the 2-piece nonlocking design did not due to material strip-out. No significant difference in maximum compression was found between the monoblock and 2-piece locking designs. However, the 2-piece nonlocking design achieved significantly higher compression. Both predictive models were shown to adequately predict compressive forces at different torque inputs for the monoblock and 2-piece locking designs but not the 2-piece nonlocking design.

Conclusion

The torque-compression relationship of a central screw baseplate is significantly affected by baseplate design. A 2-piece nonlocking baseplate reaches higher compression levels and risks material strip-out at lower insertional torques compared with a monoblock and 2-piece locking design. This has implications both on component design and on surgeon tactile feedback during surgery.

Relationship Between Insertion Torque and Compression Strength in the Reverse Total Shoulder Arthroplasty Baseplate

Reverse shoulder arthroplasty is a well-established procedure, however, there is limited data in the literature regarding adequate insertion torque and the resulting compression for glenoid baseplate fixation. In this biomechanical study, we evaluated the relationship between insertion torque and baseplate compression by simultaneously measuring the insertion torque and axial compressive forces generated by two reverse shoulder arthroplasty baseplates with central screw design. Three different bone surrogates were chosen to mimic clinical scenarios where differences in compression achieved during baseplate insertion may exist due to varying bone quality. Epoxy resin sheets were combined with the bone surrogates to simulate the glenoid vault. A digital torque gauge was used to measure insertion torque applied to the baseplate, while compression data were collected continuously from a load cell. A strong positive correlation was found between baseplate compression and insertion torque. Among the lower density bone surrogates, neither baseplate design reached maximum insertion torque (6.8 Nm) due to material strip-out. This phenomenon did not occur in denser bone surrogates. Both baseplate designs experienced a significant increase in mean baseplate compression as insertion torque increased and were found to behave similar in the denser bone surrogates. The results presented here suggest that larger compressive forces can be achieved with an increase in insertion torque in denser bone surrogates, but caution must be used when trying to achieve fixation in poor-quality bone. Clinically, this could be useful preoperatively to minimize baseplate failure, and in further studies regarding baseplate design for improved initial fixation and stability. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:871-879, 2020.

Associations of Preoperative Patient Mental Health and Sociodemographic and Clinical Characteristics With Baseline Pain, Function, and Satisfaction in Patients Undergoing Rotator Cuff Repairs

BACKGROUND

Shoulder pain and dysfunction are common indications for rotator cuff repair surgery, yet the factors that are associated with these symptoms are not fully understood.

PURPOSE/HYPOTHESIS

This study aimed to investigate the associations of patient and disease-specific factors with baseline patient-reported outcome measures (PROMs) in patients undergoing rotator cuff repair. We hypothesized that tear size and mental health status, as assessed by the Veterans RAND 12-Item Health Survey mental component score (VR-12 MCS), would be associated with baseline total Penn Shoulder Score (PSS) and its pain, function, and satisfaction subscale scores.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

We prospectively identified 12 patient factors and 12 disease-specific factors as possible statistical predictors for baseline PROMs in patients undergoing surgical repair of superior-posterior rotator cuff tears at a single institution over a 3-year period. Multivariable statistical modeling and Akaike information criterion comparisons were used to investigate the unique associations with, and relative importance of, these factors in accounting for variation in baseline PSS and its subscale scores.

RESULTS

A total of 1442 patients who had undergone surgery by 23 surgeons met inclusion criteria, with a baseline median total PSS of 38.5 (pain, 12; function, 24.2; satisfaction, 2). Adjusted R² in multivariable models demonstrated that the 24 general patient and disease-specific factors accounted for 22% to 24% of the variability in total PSS and its pain and function subscale scores. Large/massive tear size was significantly associated with worse PSS total score and function score but not pain or satisfaction scores. Lower VR-12 MCS was significantly associated with worse total PSS and all 3 subscale scores. Among other factors significantly associated with baseline PROMs were sex, race, preoperative opioid use, years of education, employment status, acromion status, and adhesive capsulitis. Lower VR-12 MCS, preoperative opioid use, female sex, and black race were the factors most strongly associated with baseline PROMs.

CONCLUSION

Large/massive tear size, lower VR-12 MCS, and several additional patient and disease-specific factors are associated with baseline PROMs in patients undergoing rotator cuff repair. Further studies are needed to investigate whether these factors will also predict poor postoperative PROMs.

Editorial Commentary: The Surgeon is the Method: Patient Positioning in Arthroscopic Repair of Shoulder Panlabral Tears

Combined tears of the anterior, posterior, and superior glenoid labrum have not been commonly reported in the literature. These lesions represent a small, but significant portion of labral injuries. Care should be taken in the diagnosis and management of these lesions because preoperative physical examination and imaging may have limited ability to detect the full extent of pathology. Arthroscopic repair of panlabral tears produces good to excellent outcomes and a low rate of recurrent instability at short-term follow-up, both when performed in the beach chair position and in the lateral decubitus position. Surgical positioning, therefore, should be based on surgeon preference.

A novel radiopaque tissue marker for soft tissue localization and in vivo length and area measurements

PURPOSE

The purpose of the study was to describe the characteristics and demonstrate proof-of-concept and clinical use of a barium sulfate infused polypropylene radiopaque tissue marker for soft tissue localization and in vivo measurement of lengths and areas.

METHODS

Marker mechanical properties were evaluated by tensile tests. Biocompatibility was evaluated following 8-12 weeks' implantation in a pig model. Proof-of-concept of marker application was performed in a human cadaveric shoulder model, and methods for CT imaging and measurement of dimensions were established. Lastly, the method of clinical use of the markers was described in one patient undergoing arthroscopic rotator cuff repair (RCR).

RESULTS

The radiopaque markers had a tensile strength of 28 ±4.7 N and were associated with minimal to mild inflammatory tissue reaction similar to polypropylene control. CT-based measurements showed relatively high precisions for lengths (0.66 mm), areas (6.97 mm2), and humeral orientation angles (2.1°) in the cadaveric model, and demonstrated 19 ±3 mm medio-lateral tendon retraction and 227 ±3 mm2 increase in tendon area in the patient during 26 weeks following RCR. No radiographic leaching, calcification or local adverse events were observed.

CONCLUSIONS

The radiopaque tissue marker was biocompatible and had adequate strength for handling and affixation to soft tissues using standard suturing techniques. The marker could be used with low-dose, sequential CT imaging to quantitatively measure rotator cuff tendon retractions with clinically acceptable accuracy. We envision the radiopaque tissue marker to be useful for soft tissue localization and in vivo measurement of tissue and organ dimensions following surgery.

Editorial Commentary: In Search of the Optimal Diagnostic Tool for Periprosthetic Joint Infections of the Shoulder

A number of perioperative diagnostic tests are currently available to evaluate for the presence of periprosthetic joint infection (PJI) in painful shoulder arthroplasties. However, data on the utility of these tests are more limited in the shoulder, with worse diagnostic performance compared with the evaluation of hip and knee PJI because of the low virulence of the commonly cultured shoulder organisms, such as Cutibacterium acnes. Diagnostic arthroscopy with culturing of arthroscopic tissue samples may allow for a more definitive diagnosis and treatment planning in patients with shoulder PJI prior to revision shoulder arthroplasty, but data on the efficacy of this procedure have been limited.

Imaging of the B2 Glenoid: An Assessment of Glenoid Wear

Background

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

Methods

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

Results

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

Conclusion

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

Validity and efficiency of a smartphone-based electronic data collection tool for operative data in rotator cuff repair

BACKGROUND

This study tested validity and efficiency of Orthopaedic Minimal Data Set (OrthoMiDaS) Episode of Care (OME).

METHODS

We analyzed 100 isolated rotator cuff repair cases in the OME database. Surgeons completed a traditional operative note and OME report. A blinded reviewer extracted data from operative notes and implant logs in electronic medical records by manual chart review. OME and electronic medical record data were compared with data counts and agreement between 40 variables of rotator cuff disease and repair procedures. Data counts were assessed using raw percentages and McNemar test (with continuity correction). Agreement of categorical variables was analyzed using Cohen κ (unweighted) and of numerical variables using the concordance correlation coefficient (CCC). Efficiency was assessed by median time to complete.

RESULTS

OME database had significantly higher data counts for 25% (10/40) of variables. A high level of proportional and statistical agreement was demonstrated between the data. Among 35 categorical variables, proportional agreement was perfect for 17%, almost perfect (0.81 ≤ κ ≤ 1.00) for 37%, substantial (0.61 ≤ κ ≤ 0.80) for 20%, moderate (0.41 ≤ κ ≤ 0.60) for 14%, fair (0.21 ≤ κ ≤ 0.40) for 6%, and slight (0.0 ≤ κ ≤ 0.20) for 6%. Of 5 numerical variables, agreement was almost perfect (CCC > 0.99) for 20% and poor (CCC < 0.90) for 80%. Median OME completion time was 161.5 seconds (interquartile range, 116-224.5).

CONCLUSION

OME is an efficient, valid tool for collecting comprehensive, standardized data on rotator cuff repair.

Accuracy of 3-Dimensional Planning, Implant Templating, and Patient-Specific Instrumentation in Anatomic Total Shoulder Arthroplasty

BACKGROUND

Use of 3-dimensional (3D) computed tomography (CT) preoperative planning and patient-specific instrumentation has been demonstrated to improve the accuracy of glenoid implant placement in total shoulder arthroplasty (TSA). The purpose of this study was to compare the accuracy of glenoid implant placement in primary TSA among different types of instrumentation used with the 3D CT preoperative planning.

METHODS

One hundred and seventy-three patients with end-stage glenohumeral arthritis were enrolled in 3 prospective studies evaluating patient-specific instrumentation and 3D preoperative planning. All patients underwent preoperative 3D CT planning to determine optimal glenoid component and guide pin position based on surgeon preference. Patients were placed into 1 of 5 instrument groups used for intraoperative guide pin placement: (1) standard instrumentation, (2) standard instrumentation combined with use of a 3D glenoid bone model containing the guide pin, (3) use of the 3D glenoid bone model combined with single-use patient-specific instrumentation, (4) use of the 3D glenoid bone model combined with reusable patient-specific instrumentation, and (5) use of reusable patient-specific instrumentation with an adjustable, reusable base. Postoperatively, all patients underwent 3D CT to compare actual versus planned glenoid component position. Deviation from the plan (in terms of orientation and location) was compared across groups on the basis of absolute differences and outlier analysis. Univariable and multivariable comparisons were performed. As the initial analyses showed no significant differences in preoperative factors or in deviation from the plan between Groups 1 and 2 or between Groups 4 and 5 across studies, the final analysis was across 3 major treatment groups: standard instrumentation (Groups 1 and 2), single-use patient-specific instrumentation (Group 3), and reusable patient-specific instrumentation (Groups 4 and 5).

RESULTS

In nearly all comparisons, there were no significant differences in the deviation from the plan (absolute differences or outlier frequency) for glenoid implant orientation or location across the 3 major treatment groups.

CONCLUSIONS

This study did not demonstrate that any type of patient-specific instrumentation resulted in consistent differences in accuracy of glenoid implant placement in primary TSA with 3D CT preoperative planning. Surgeons have multiple patient-specific instrumentation options available for improving accuracy of glenoid implant placement when compared with 2D imaging without patient-specific instrumentation.

LEVEL OF EVIDENCE

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

Tear characteristics and surgeon influence repair technique and suture anchor use in repair of superior-posterior rotator cuff tendon tears

BACKGROUND

The factors that associate with surgical decisions about repair technique and the number of suture anchors used in rotator cuff repair have not been previously investigated. This study investigated the extent to which patient, surgeon, and surgical factors associate with performing single-row vs. double-row repair technique and ultimately with the number of suture anchors used.

METHODS

Our institution's prospective surgical cohort was queried for patients undergoing suture anchor repair of superior-posterior rotator cuff tendon tears between February 2015 and August 2017. Exclusion criteria were patients with isolated subscapularis tears, tears that were not repaired, repairs without suture anchors, repairs involving graft augmentation, and repairs by surgeons with fewer than 10 cases. Multivariable statistical modeling was used to investigate associations between patient and surgical factors and the choice of repair technique and number of suture anchors used.

RESULTS

A total of 925 cases performed by 13 surgeons met inclusion criteria. Tear type (full thickness), tear size (medium, large, and massive), a greater number of torn tendons, repair type (arthroscopic), and surgeon were significantly associated with performing a double-row over a single-row repair. Tear size, a greater number of torn tendons, double-row repair technique, and surgeon were significantly associated with a greater number of anchors used for repair.

CONCLUSIONS

Our findings suggest that in the absence of data to conclusively support a clinical benefit of one repair technique over another, surgeons' training, experience, and inherent practice patterns become the primary factors that define their surgical methods.

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.

The Volume-Value Relationship in Shoulder Arthroplasty

Improving value in shoulder arthroplasty has gained increasing importance as procedure volume increases. To enhance the value of shoulder arthroplasty, an improvement of outcomes or a decrease in associated costs must occur. With the recent shift to a value-based care delivery model, analysis of the effects of surgical volume presents an opportunity to improve outcomes and reduce costs in shoulder arthroplasty. There are multiple reports in the literature expanding on the relationship between increased surgeon and hospital procedure volume and increased value for shoulder arthroplasty, by way of improved outcomes or decreased cost. This article highlights these studies.

Scapular Notching After Reverse Total Shoulder Arthroplasty: Prediction Using Patient-Specific Osseous Anatomy, Implant Location, and Shoulder Motion

BACKGROUND

Scapular notching is frequently observed following reverse total shoulder arthroplasty (rTSA), although the etiology is not well understood.

METHODS

Twenty-nine patients with preoperative computed tomography (CT) scans who underwent rTSA with a Grammont design were evaluated after a minimum of 2 years of follow-up with video motion analysis (VMA), postoperative three-dimensional (3D) CT, and standard radiographs. The glenohumeral range of motion demonstrated by the VMA and the postoperative implant location on the CT were used in custom simulation software to determine areas of osseous impingement between the humeral implant and the scapula and their relationship to scapular notching on postoperative CT. Patients with and without notching were compared with one another by univariable and multivariable analyses to determine factors associated with notching.

RESULTS

Seventeen patients (59%) had scapular notching, which was along the posteroinferior aspect of the scapular neck in all of them and along the anteroinferior aspect of the neck in 3 of them. Osseous impingement occurred in external rotation with the arm at the side in 16 of the 17 patients, in internal rotation with the arm at the side in 3, and in adduction in 12. The remaining 12 patients did not have notching or osseous impingement. Placing the glenosphere in a position that was more inferior (by a mean of 3.4 ± 2.3 mm) or lateral (by a mean of 6.2 ± 1.4 mm) would have avoided most impingement in the patients' given range of motion. Notching was associated with glenosphere placement that was insufficiently inferior (mean inferior translation, -0.3 ± 3.4 mm in the notching group versus 3.0 ± 2.9 mm in the no-notching group; p = 0.01) or posterior (mean, -0.3 ± 3.5 mm versus 4.2 ± 2.2 mm; p < 0.001). Two-variable models showed inferior and posterior (area under the curve [AUC], 0.887; p < 0.001), inferior and lateral (AUC, 0.892; p < 0.001), and posterior and lateral (AUC, 0.892; p < 0.001) glenosphere positions to be significant predictors of the ability to avoid scapular notching.

CONCLUSIONS

Osseous impingement identified using patients' actual postoperative range of motion and implant position matched the location of scapular notching seen radiographically. Inferior, lateral, and posterior glenosphere positions are all important factors in the ability to avoid notching. Only small changes in implant position were needed to avoid impingement, suggesting that preoperative determination of the ideal implant position may be a helpful surgical planning tool to avoid notching when using this implant design.

LEVEL OF EVIDENCE

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

Mobile technology and telemedicine for shoulder range of motion: validation of a motion-based machine-learning software development kit

BACKGROUND

Mobile technology offers the prospect of delivering high-value care with increased patient access and reduced costs. Advances in mobile health (mHealth) and telemedicine have been inhibited by the lack of interconnectivity between devices and software and inability to process consumer sensor data. The objective of this study was to preliminarily validate a motion-based machine learning software development kit (SDK) for the shoulder compared with a goniometer for 4 arcs of motion: (1) abduction, (2) forward flexion, (3) internal rotation, and (4) external rotation.

METHODS

A mobile application for the SDK was developed and "taught" 4 arcs of shoulder motion. Ten subjects without shoulder pain or prior shoulder surgery performed the arcs of motion for 5 repetitions. Each motion was measured by the SDK and compared with a physician-measured manual goniometer measurement. Angular differences between SDK and goniometer measurements were compared with univariate and power analyses.

RESULTS

The comparison between the SDK and goniometer measurement detected a mean difference of less than 5° for all arcs of motion (P > .05), with a 94% chance of detecting a large effect size from a priori power analysis. Mean differences for the arcs of motion were: abduction, -3.7° ± 3.2°; forward flexion, -4.9° ± 2.5°; internal rotation, -2.4° ± 3.7°; and external rotation -2.6° ± 3.4°.

DISCUSSION

The SDK has the potential to remotely substitute for a shoulder range of motion examination within 5° of goniometer measurements. An open-source motion-based SDK that can learn complex movements, including clinical shoulder range of motion, from consumer sensors offers promise for the future of mHealth, particularly in telemonitoring before and after orthopedic surgery.