Characteristics of unsatisfactory shoulder arthroplasties

Surgical management of biconcave glenoids: a scoping review

Biconcave (B2) glenoids, characterized by significant posterior glenoid bone loss and a biconcave wear pattern, are a challenging pathology in shoulder surgery. Significant bone defects present in B2 glenoids increases the risk of complications and rates of failure for operative patients with glenohumeral osteoarthritis. Diagnosing this entity is of pivotal importance, and can be accomplished with imaging and a comprehensive clinical investigation. There are no clear-cut guidelines for management, but options include hemiarthroplasty, anatomic total shoulder arthroplasty, and reverse shoulder arthroplasty. In recent years, modern techniques such as corrective reaming, bone grafts, and the use of augmented components have improved patient outcomes. Educating prospective patients is essential for reaching a shared management decision, setting appropriate expectations, and optimizing prognostic outcomes.

Functional Outcomes and a Review of Management Options for Revision Shoulder Arthroplasty

Introduction

Increase in the number of primary shoulder arthroplasty has led to an increase in the number of revisions which presents many complex challenges and often has inferior outcomes.

Materials and Methods

Data was collected retrospectively, and patients were classified using Dines classification. Comprehensive case reviews were done to identify preoperative and intra-operative challenges. The primary outcome measure was Oxford shoulder score (OSS). The secondary measures were range of motion (ROM) and patient satisfaction (very satisfied, satisfied, not satisfied or worse).

Results

A total of 32 patients were identified with a mean age of 67.64 years and the most common cause of revision was a combination of bone and soft tissue failure (39.3%). All patients (n=8) with hemiarthroplasty had rotator cuff deficiency while patients with resurfacing had both rotator cuff failure and bony erosion. Four patients needed a proximal humeral osteotomy and six patients needed allograft reconstruction of the glenoid for bone loss. Twenty-one shoulders were revised to reverse total shoulder arthroplasty (TSA), 2 to anatomical TSA and 5 were left with cement spacer in situ. Mean duration of follow-up was 41.6 months. Mean OSS at the last follow-up was 26.88 with statistically significant improvement in ROM. There was no statistical difference in clinical outcomes (p>0.05) based on the type of primary prosthesis or cause of revision. A total of 70% patients were pain free. Patients with infection had inferior outcomes with a mean OSS of 17.

Conclusion

Management of patients with failed shoulder arthroplasty is often challenging but has good clinical outcome except in infections.

Patients 75 years or older with primary glenohumeral arthritis and an intact rotator cuff show similar clinical improvement after reverse or anatomic total shoulder arthroplasty

BACKGROUND

The optimal management of primary glenohumeral arthritis (GHOA) in the elderly is an ongoing topic of debate. The purpose of this study was to compare functional outcomes and complications in patients aged 75 years or older treated with anatomic total shoulder arthroplasty (TSA) or reverse shoulder arthroplasty (RSA) for primary GHOA with an intact rotator cuff.

METHODS

A retrospective study was performed on a prospectively maintained database which was queried for patients 75 years of age or older who underwent TSA or RSA for primary GHOA with an intact rotator cuff at a single institution between 2012 and 2021 with minimum 2-year follow-up. Patient-reported outcomes (PROs), including Visual Analog Scale for pain, American Shoulder and Elbow Surgeons, and Subjective Shoulder Value, as well as active range of motion including forward flexion, external rotation, internal rotation, were collected preoperatively and postoperatively. Complications, reoperations, and satisfaction were also recorded. The percentage of patients achieving clinically significant improvement was evaluated with the minimally clinical important difference, substantial clinical benefit, and patient acceptable symptomatic state for each PRO.

RESULTS

One-hundred and 4 patients were available for analysis, including 67 TSA patients and 37 RSAs with a mean follow-up of 39.4 months. Preoperative baseline characteristics, PROs, and range of motion were similar between groups. RSA was more commonly performed for eccentric glenoid wear (Walch B2/B3, 62% vs. 22%; P < .001). While clinical outcomes improved comparably in both groups, the TSA cohort showed significantly greater improvement in external rotation (36° vs. 26°; P = .013). Both cohorts had low revision (3% for TSA vs. 0% for RSA) and complication (7% for TSA vs. 5% for RSA; P = .677) rates. Satisfaction was similar in both groups (93% for TSA vs. 92% for RSA; P = .900). Clinically significant improvement was comparable between groups based on the American Shoulder and Elbow Surgeons score (minimally clinical important difference, 93% for TSA vs. 100% for RSA; substantial clinical benefit, 82% vs. 95%; patient acceptable symptomatic state, 67% vs. 78%; P > .05).

CONCLUSION

In this retrospective small sample size comparison study, TSA and RSA provide similar short-term clinical outcomes for patients 75 years and older with primary GHOA and an intact rotator cuff. Complication and revision rates are comparably low at short-term follow-up. Our data suggests that advanced age alone should not be used as a decision-making tool for TSA vs. RSA in the setting of primary GHOA with an intact rotator cuff.

Biomechanics of subscapularis V-shaped tenotomy compared to standard tenotomy

BACKGROUND

Subscapularis function is critical after anatomic total shoulder arthroplasty (aTSA). Recently, however, a technique has been described that features a chevron or V-shaped subscapularis tendon cut (VT). This biomechanical study compared repair of the standard tenotomy (ST), made perpendicular to the subscapularis fibers, to repair of the novel VT using cyclic displacement, creep, construct stiffness, and load to failure.

METHODS

This biomechanical study used 6 pairs of fresh frozen paired cadaveric shoulder specimens. One specimen per each pair underwent VT, the other ST. Subscapularis tenotomy was performed 1 cm from the insertion onto the lesser tuberosity. For VT, the apex of the V was 3 cm from the lesser tuberosity. After tenotomy, each humerus underwent humeral head arthroplasty. Eight figure-of-8 sutures were used to repair the tenotomy (Ethibond Excel; Ethicon, US LLC). Specimens were cyclically loaded from 2 to 100 N at 45 degrees abduction at a rate of 1 Hz for 3000 cycles. Cyclic displacement, creep, and stiffness and load to failure were measured.

RESULTS

Cyclic displacement did not differ significantly between the ST and VT from 1 to 3000 cycles. The difference in displacement between the V-shaped and standard tenotomy at 3000 cycles was 1.57 mm (3.66 ± 1.55 mm vs. 5.1 ± 2.8 mm, P = .31, respectively). At no point was the V-shape tenotomy (VT) >3 mm of average displacement, whereas the standard tenotomy (ST) averaged 3 mm of displacement after 3 cycles. Creep was significantly lower for VT in cycles 1 through 3. For all cycles, stiffness was not significantly different in the VT group compared with the ST group. Load to failure was not statistically significant in the VT compared to the standard tenotomy throughout all cycles (253.2 ± 27.7 N vs. 213.3 ± 76.04 N; P = .25, respectively). The range of load to failure varied from 100 to 301 N for standard tenotomy compared with 216 to 308 N for VT.

CONCLUSION

This study showed that VT and ST demonstrated equivalent stiffness, displacement, and load to failure. VT had the benefit of less creep throughout the first 3 cycles, although there was no difference from cycle 4 to 3000. The VT had equivalent biomechanical properties to the ST at time zero, an important first step in our understanding of the technique. The VT technique warrants further clinical study to determine if the technique has clinical benefits over ST following aTSA.

Is the Number of Citations Related to the Study Methodology in Shoulder Arthroplasty Literature? A Bibliometric and Statistical Analysis of Current Evidence

Background

We reviewed the shoulder arthroplasty (SA) literature to correlate citations, methodological characteristics and quality of most-cited articles in this field. We hypothesized that a greater number of citations would be found for high-quality clinical studies.

Methods

We searched the Web of Knowledge database for the 50 most-cited articles about SA and collected author name, publication year, country of origin, journal, article type, level of evidence (LoE), subject of paper, type of arthroplasty and metrics (number of citations and citation rate). Coleman Methodology Score (CMS) was computed for clinical articles. Statistical analysis of variance and correlation coefficients were used to investigate the relationship between different variables.

Results

Out of the selected 50 studies on SA, 26% were nonclinical. There were 15,393 citations overall (mean 307.8), with a mean 19.5 citations per year (range 48.3-6.7). Thirty or 60% of all articles were LoE IV. All studies were published between 1984 and 2011 in 8 journals. Reverse SA (RSA) was the most common subject (36% of studies). The United States was the country responsible for most contributions (50% of studies). CMS ranged from 81 to 38 (mean 59.6). RSA received the highest number of citations (P < .001), independently from country of origin (P = .137) and LoE (P = .723). CMS correlated with citation rate (r = 0.397; P = .013) and publication year (tau = 0.397; P = .013), but not with LoE (P = .204).

Conclusion

In SA literature, citation rate positively correlates with methodological quality of a study, independently from publication country and LoE. Among most-cited papers, RSA is the most common standalone subject.

Influence of acromioclavicular joint arthritis on outcomes after reverse total shoulder

Background

Although substantial motion at the acromioclavicular joint (ACJ) occurs during overhead shoulder motion, the influence of ACJ arthritis on postoperative outcomes of patients undergoing reverse total shoulder arthroplasty (rTSA) is unclear. We assessed the influence of ACJ arthritis, defined by degenerative radiographic changes, and its severity on clinical outcomes after primary rTSA.

Methods

We conducted a retrospective review of a prospectively collected shoulder arthroplasty database of patients that underwent primary rTSA with a minimum 2-year clinical follow-up. Imaging studies of included patients were evaluated to assess ACJ arthritis classified by radiographic degenerative changes of the ACJ; severity was based upon size and location of osteophytes. Both the Petersson classification and the King classification (a modified Petersson classification addressing superior osteophytes and size of the largest osteophyte) were used to evaluate the severity of degenerative ACJ radiographic changes. Severe ACJ arthritis was characterized by large osteophytes (≥2 mm). Active range of motion (ROM) in abduction, forward elevation, and external and internal rotation as well as clinical outcome scores (American Shoulder and Elbow Surgeons Shoulder, Constant, Shoulder Pain and Disability Index, simple shoulder test, University of California, Los Angeles scores) were assessed both preoperatively and at the latest follow-up; outcomes were compared based on severity of ACJ arthritis. Multivariable linear regression models were used to determine whether increasing severity of ACJ arthritis was associated with poorer outcomes.

Results

A total of 341 patients were included with a mean age of 71 ± 8 years and 55% were female. The mean follow-up was 5.1 ± 2.4 years. Preoperatively, there were no differences in outcomes based on the severity of ACJ pathology. Postoperatively, there were no differences in outcomes based upon the severity of ACJ arthritis except for greater preoperative to postoperative improvement in active internal rotation in patients with normal or grade 1 ACJ arthritis vs. grade 2 and 3 (3 ± 2 vs. 1 ± 2 and 1 ± 3, P = .029). Patients with ACJ arthritis and osteophytes ≥2 mm had less favorable Shoulder Pain and Disability Index scores, corresponding to greater pain (-49.3 ± 21.5 vs. -41.3 ± 26.8, P = .015). On multivariable linear regression, increased severity of ACJ arthritis was not independently associated with poorer postoperative ROM or outcome scores.

Conclusion

Overall, our results demonstrate that greater ACJ arthritis severity score is not associated with poorer outcome scores and has minimal effect on ROM. However, patients with the largest osteophytes (≥2 mm) did have slightly worse pain postoperatively. Radiographic presence of high-stage ACJ arthritis should not alter the decision to undergo rTSA.

The Use of an External Cutting Guide for Patient-Specific Bone Grafting in Reverse Total Shoulder Arthroplasty: A Novel Technique

Glenoid bone loss remains a substantial challenge in reverse shoulder arthroplasty and failure to address such bone loss may lead to implant malpositioning, instability and/or premature baseplate loosening. Currently, management of glenoid bone loss can be achieved by metal augmentation or bone grafting (ie, autograft or allograft). At the present time, options for creating and shaping glenoid bone grafts include free-hand techniques and simple reusable cutting guides that create the graft at a standard shape/angle. To our knowledge, there is no external guide available that enables surgeons to accurately prepare the bone graft to the desired dimensions/shape (ie, trapezoid or biplanar) to correct the glenoid deformity. In this article, we present a novel surgical technique that utilizes an external guide for creating a patient-specific bone graft to address glenoid deformity in the setting of reverse total shoulder arthroplasty.

Rehabilitation following shoulder arthroplasty: a survey of current clinical practice patterns of Italian physiotherapists

BACKGROUND

The incidence of Total Shoulder Arthroplasty (TSA) and Reverse Total Shoulder Arthroplasty (RTSA) is constantly increasing. As a result, the interest in post-surgical rehabilitation has grown, since it is crucial in order to achieve full recovery and successful outcomes. The first aim of this study is to investigate the Italian physiotherapists (PTs) clinical practice in the management of patients with TSA and RTSA and to compare it with the best evidence available in the literature. The second purpose of this study is to assess any existing difference between the survey answers and the different sample subgroups.

MATERIALS AND METHODS

This cross-sectional observation study was designed following the CHERRIES checklist and the STROBE guidelines. A 4-sections survey with a total of 30 questions was developed for investigating post-surgery rehabilitation management in patient with TSA and RTSA. The survey was sent to Italian PTs from December 2020 until February 2021.

RESULTS

Six-hundred and seven PTs completed the survey regarding both TSA and RTSA; 43.5% of participants (n = 264/607) stated that TSA is more likely to dislocate during abduction and external rotation. Regarding reverse prosthesis, 53.5% (n = 325/607) affirmed RTSA is more likely to dislocate during internal rotation, adduction and extension. In order to recover passive Range of Motion (pROM), 62.1% (n = 377/607) of participants reported that they gain anterior flexion, abduction, internal rotation, external rotation up to 30°, with full pROM in all directions granted at 6-12 weeks. Regarding the active ROM (aROM), 44.2% (n = 268/607) of participants stated that they use active-assisted procedures within a range under 90° of elevation and abduction at 3-4 weeks and higher than 90° at 6-12 weeks, with full recovery at a 3-month mark. Sixty-five point seven percent of the sample (n = 399/607) declared that, during the rehabilitation of patients with TSA, they tend to focus on strengthening the scapular and rotator cuff muscles, deltoid, biceps and triceps. Conversely, 68.0% (n = 413/607) of participants stated that, for the rehabilitation of patients with RTSA, they preferably focus on strengthening the periscapular and deltoid muscles. Finally, 33.1% (n = 201/607) of participants indicated the instability of the glenoid prosthetic component as the most frequent complication in patients with TSA, while 42.5% (n = 258/607) of PTs identified scapular neck erosion as the most frequent post-RTSA surgery complication.

CONCLUSIONS

The clinical practice of Italian PTs effectively reflects the indications of the literature as far as the strengthening of the main muscle groups and the prevention of movements, which may result in a dislocation, are concerned. Some differences emerged in the clinical practice of Italian PTs, regarding the restoration of active and passive movement, the starting and progression of muscle strengthening and the return to sport (RTS). These differences are actually quite representative of the current knowledge in post-surgical rehabilitation for shoulder prosthesis in the rehabilitation field.

LEVEL OF EVIDENCE

V.

Cementless Metal-Free Ceramic-Coated Shoulder Resurfacing

Shoulder resurfacing is a versatile, bone-conserving procedure to treat arthritis, avascular necrosis, and rotator cuff arthropathy. Shoulder resurfacing is of interest to young patients who are concerned about implant survivorship and those in need of a high level of physical activity. Using a ceramic surface reduces wear and metal sensitivity to clinically unimportant levels. Between 1989 and 2018, 586 patients received cementless, ceramic-coated shoulder resurfacing implants for arthritis, avascular necrosis, or rotator cuff arthropathy. They were followed for a mean of 11 years and were assessed using the Simple Shoulder Test (SST) and Patient Acceptable Symptom State (PASS). CT scans were used in 51 hemiarthroplasty patients to assess the glenoid cartilage wear. Seventy-five patients had a stemmed or stemless implant in the contralateral extremity. A total of 94% of patients had excellent or good clinical results and 92% achieved PASS. 6% of patients required a revision. A total of 86% of patients preferred their shoulder resurfacing prosthesis over a stemmed or stemless shoulder replacement. The glenoid cartilage wear at a mean of 10 years was 0.6 mm by a CT scan. There were no instances of implant sensitivity. Only one implant was removed due to a deep infection. Shoulder resurfacing is an exacting procedure. It is clinically successful, with excellent long-term survivorship in young and active patients. The ceramic surface has no metal sensitivity, very low wear, and, therefore, it is successful as a hemiarthroplasty.

Postoperative Rehabilitation After Shoulder Arthroplasty

Total shoulder arthroplasty (TSA), including anatomic TSA (aTSA) and reverse TSA (rTSA), has increased in popularity due to reliably good patient outcomes. Postoperative physical therapy (PT) is considered essential to the success of this operation and has become standard practice. The authors present general rehabilitation principles as well as preferred postoperative PT protocols for aTSA and rTSA, which are based on evidence-based literature and the different early postoperative concerns for each of these procedures.

3D Printed Patient-Specific Cutting Guides for Bone Grafting in Reverse Shoulder Arthroplasty: A Novel Technique

Glenoid bone loss remains a challenge in shoulder arthroplasty. Addressing substantial bone loss is essential to ensure proper function and stability of the shoulder prosthesis and to prevent baseplate loosening and subsequent revision surgery. Current options for creating and shaping glenoid bone grafts include free-hand techniques and simple reusable cutting guides that cut the graft at a standard angle. There is currently no patient-specific device available that enables surgeons to accurately prepare the bone graft and correct glenoid deformity. We present a novel surgical technique using three-dimensional (3D)-printed cutting guides to create a patient-specific bone graft to address glenoid deformity in the setting of reverse shoulder arthroplasty.

Glenoid wear and its impact on clinical results after humeral head replacement using a single prosthesis in cuff tear arthropathy with more than 8 years of follow-up

BACKGROUND

Glenoid wear (GW) is a long-term complication after humeral head replacement (HHR) and is one of the major reasons for revision surgery. This study aimed to evaluate GW at >8 years of follow-up after HHR in patients with cuff tear arthropathy (CTA) by use of a modified classification of GW, to examine the relationship between GW and clinical outcomes, and to identify risk factors for GW progression.

METHODS

This retrospective case-series study included 34 shoulders that were monitored for >8 years after HHR in patients with CTA (13 men and 21 women; mean age at surgery, 70.9 years [range, 55-82 years]). Patients were monitored for a mean of 10.3 years (range, 8.1-13.2 years). GW was classified using plain radiographs as follows: grade 0, no remarkable postoperative changes; grade 1, postoperative glenohumeral joint space narrower than preoperative glenohumeral joint space; grade 2, contact between glenoid and humeral head prosthesis; and grade 3, glenoid erosion. Grade 3 cases were further classified into the following subtypes: grade 3A, partial erosion of anterior glenoid; grade 3B, partial erosion of superior glenoid; and grade 3C, concentric erosion of glenoid. Clinical outcomes including range of motion (active flexion and active external rotation) and postoperative pain (Constant score) were compared between grade 0-2 shoulders and grade 3 shoulders, as well as between the grade 3 subtypes. Age, sex, preoperative range of motion, preoperative pain, and number of ruptured tendons were analyzed as possible risk factors for progression to grade 3.

RESULTS

The final GW grade was grade 0 in 3 shoulders, grade 1 in 10, grade 2 in 6, and grade 3 in 15 (grade 3A in 2, grade 3B in 6, and grade 3C in 7). The grade 3 group had lower pain scores (10.7 ± 6.2 vs. 14.2 ± 1.9, P = .044) and limited active flexion (108.2° ± 42.3° vs. 140.6° ± 26.7°, P = .041) compared with the grade 0-2 group. Subtype comparison showed that the grade 3B group had lower pain scores (7.0 ± 6.7 vs. 15.0 ± 0.0, P = .007) and limited active flexion (80.0° ± 26.2° vs. 140.8° ± 27.5°, P = .010) compared with the grade 3C group. Limited preoperative active external rotation was an individual risk factor for grade 3 GW (odds ratio, 0.93; 95% confidence interval, 0.88-0.99; P = .009).

CONCLUSIONS

In the long term (>8 years) after HHR with tendon transfer in patients with CTA, patients with the development of grade 3C GW ultimately achieve pain relief even without revision surgery whereas grade 3B GW is associated with persistent pain and might require revision surgery.

Clinical results and 10-year survivorship of the Synthes Epoca resurfacing total shoulder arthroplasty

Aims

This prospective cohort study reports the 10-year survivorship, patient-reported outcome measures and radiographic outcomes of the first series of the Epoca resurfacing head total shoulder arthroplasty.

Methods

From July 2008 to July 2014, 59 Epoca resurfacing head total shoulder arthroplasties were implanted in 50 patients by a single surgeon. Minimum 4.8 year and maximum 11.3 year follow-up (mean: 7.9 years) was analysed using the latest available Oxford Shoulder Score. Kaplan-Meier survivorship analysis was performed with revision as the end point. Most recent radiographs were reviewed for component radiolucency, osteolysis and proximal humeral migration.

Results

Two shoulders underwent revision (3.4%); one for pain with posterior subluxation following a fall, the other for pain with failure of the glenoid. Kaplan-Meier analysis revealed 10-year survivorship of 98.2% (95% confidence intervals: 88.0%-99.8%). Mean Oxford Shoulder Score improved significantly compared to pre-operative values from 18.2 (5-45) to 46.6 (36-48) (p < 0.001). Fifty-three shoulders underwent radiographic analysis (89.8%). This revealed humeral radiolucency in two cases (3.8%), glenoid radiolucency in three cases (5.7%) and radiographic rotator cuff failure in eight cases (15.1%).

Conclusion

This prospective cohort study shows excellent 10-year survivorship, medium to long-term clinical and radiological results and for the Synthes Epoca resurfacing head total shoulder arthroplasty.

Evidence level

IV.

Stemless anatomic total shoulder arthroplasty: surgical technique and review of the literature

Stemless anatomic total shoulder arthroplasty (aTSA) is a promising option for the treatment of degenerative disease in patients. This novel technique avoids the stem-related complications associated with the traditional stemmed aTSA. Stemless aTSA offers additional benefits such as decreased operative time, preservation of bone stock, improved radiographic outcomes, and easier revision. Moreover, loading of the metaphyseal region rather than the diaphysial region with traditional stemmed implants can decrease stress shielding. When compared to stemmed-implants, stemless aTSA has demonstrated similar outcomes and complication rates. The purpose of this article is to analyze published outcomes and complications following the utilization of stemless aTSA. Additionally, key aspects of the surgical technique that may promote optimal results in stemless aTSA implantation are presented.

The most influential studies concerning revision shoulder arthroplasty research

Background

Bibliometric analysis is a unique tool that can be used to study the characteristics and trends of a given topic. This study aimed to report on the most influential studies concerning revision shoulder arthroplasty research.

Methods

On July 4th, 2022, the Institute of Scientific Information (ISI) Web of Knowledge Database was used to identify articles concerning revision shoulder arthroplasty research. The top 50 most cited articles were selected and analyzed.

Results

The mean number of citations was 142 (median: 97; range 599-70). Most articles were published in the 2010s (56%), followed by the 2000s (38%), and 1990s (6%). The most common level of evidence (LOE) was LOE II (42%) followed by LOE IV (38%), LOE I and III each had 10%. The greatest number of papers were published in the Journal of Shoulder and Elbow Surgery (46%), followed by the Journal of Bone and Joint Surgery- American Version (14%).

Conclusion

This review can serve as a useful tool to study the most influential articles concerning revision shoulder arthroplasty research. Most of the articles were classified as clinical outcomes (62%), followed by natural history/epidemiology (12%), and surgical technique (10%). Our findings suggest that high-quality studies (LOE I) are lacking and other areas of research besides clinical outcomes are not as well studied.

Restoration of the native humeral anatomy during stemless anatomic total shoulder arthroplasty: a radiographic comparison of intramedullary versus freehand resection

BACKGROUND

During anatomic total shoulder arthroplasty (aTSA), the humeral head can be resected with or without the use of an intramedullary cutting guide, the former referred to as intramedullary (IM) resection and the latter referred to as freehand (FH) resection. Outcomes following aTSA are predicated upon the restoration of the native humeral anatomy, which can be more challenging with stemless implants. To date, no studies have determined which method of humeral head resection is superior in restoring native anatomy. Our purpose was to determine whether FH or IM resection was superior in restoring native anatomy during aTSA with stemless implants.

METHODS

A review of all patients who underwent aTSA using the stemless Tornier Simpliciti Shoulder System at two academic institutions by two separate surgeons between January 2017 and June 2020 was performed. One surgeon at one institution performed stemless aTSA using the IM resection technique, while the second surgeon utilized the FH resection technique. Patients were excluded if they underwent surgery for an indication other than glenohumeral osteoarthritis, if they received a short-stem or standard-stem implant, or if they lacked adequate preoperative and postoperative Grashey radiographs. One hundred eleven patients across both institutions (51 IM, 60 FH) were included for the final radiographic assessment. The humeral head height (HH) and neck-shaft angle (NSA) were measured on preoperative and postoperative Grashey radiographs. The centers of rotation (CORs) were measured on postoperative Grashey radiographs. Patients were classified as having acceptable restoration of their native anatomy if the change (Δ) in COR or HH was ≤3 mm and ≤ 5 mm, respectively, or if the postoperative NSA was ≥130°.

RESULTS

IM resection had the greatest acceptable restoration of COR (90.2% IM versus 70% FH, P = .009), HH (96.1% IM vs. 63.3% FH, P < .001), and NSA (96.1% IM vs. 78.3% FH, P = .006) relative to FH resection. The mean postoperative NSAs for the IM and FH cohorts were 134.4° (±2.1°) and 133.8° (±5.4°), respectively (P = .208). The mean ΔCORs for the IM and FH groups were 1.2 (±1.5) and 2.3 (±1.2) mm, respectively (P < .001). Finally, the mean ΔHHs for the IM and FH cohorts were 1.7 (±1.4) and 4.4 (±2.9) mm, respectively (P < .001).

CONCLUSIONS

Restoration of the native humeral anatomy following stemless aTSA occurred at a significantly higher rate when using IM vs. FH resection.

Risk factors for eccentric glenoid wear after humeral head replacement for cuff tear arthropathy

Background

In our previous report, glenoid wear (GW) after humeral head replacement for cuff tear arthropathy was classified with modified Goya’s classification (grade 0-3), and, among 3 subtypes of grade 3 (glenoid bone erosion), grade 3B (superior eccentric erosion) showed significantly more pain and limited active flexion postoperatively compared to grade 3C (concentric erosion). The purpose of this study was to detect individual risk factors for the progression to grade 3B GW.

Methods

Seventy-nine shoulders in 70 patients who were followed up for a mean of 8.2 years (range, 5.0-13.2 years), including 29 men and 41 women, with a mean age at the surgery of 71.1 years (range, 54-87 years), were reviewed. Atrophy and fatty degeneration of torn cuff muscle, preoperative humeral head displacement (superior translation ratio [STR], anterior translation ratio, and other several parameters) on preoperative magnetic resonance imaging, and other individual factors were analyzed as possible risk factors.

Results

GW at the final follow-up was grade 0: 5 shoulders, grade 1: 17, grade 2: 20, and grade 3: 37 (3A: 4, 3B: 22, and 3C: 11). Preoperative higher STR was defined as a risk factor for grade 3 GW (odds ratio, 35.5; 95% confidence interval, 1.8-693.0; P = .018). Comparison among the three subtypes of grade 3 showed that patients with grade 3B GW had larger STR than 3C (41.4 ± 14.2% vs. 23.5 ± 13.3 % P = .006).

Conclusion

Patients with preoperative high STR are considered to have a risk for grade 3B GW, which possibly relates to poor clinical outcome and future revision.

Improved mechanical fixation of an all-polyethylene glenoid reduces postoperative radiolucent lines

BACKGROUND

The rationale for advances in implant design is to improve performance in comparison to their predecessors. The purpose of this study was to compare a newer, self-pressurizing peripheral peg glenoid to a traditional polyethylene pegged glenoid through biomechanical evaluation and a retrospective radiographic and clinical review.

METHODS

Three testing conditions (uncemented, partially cemented, and fully cemented) were chosen to assess the 2 component designs in a foam block model. The number of hammer hits to seat the component, amount of time to seat the component, and resistance-to-seat were collected. The implants were then cyclically loaded following ASTM F2028-17 testing standard. Clinically, postoperative radiographs of patients with a self-pressurized glenoid component (n = 225 patients) and traditional glenoid component (n = 206 patients) were evaluated for radiolucent lines and glenoid seating at various timepoints. Clinical outcomes (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form, Simple Shoulder Test, and visual analog scale pain scores) and complications were recorded. The presence of radiolucent lines at the bone-cement interface was evaluated using the Modified Franklin Grade and the Lazarus grade.

RESULTS

The self-pressurizing glenoid design required significantly more hammer hits than traditional glenoid designs in all groups tested (P < .029). Moreover, the self-pressurizing design had significantly more resistance-to-seat than traditional components in both the uncemented and partially cemented group (P < .002). No difference in resistance-to-seat was found between designs in the fully cemented group. The uncemented and partially cemented groups did not survive the full 50,000 cycles; however the self-pressurizing design had significantly less motion than the traditional design (P < .001). No differences between component designs were found in the fully cemented group at 50,000 cycles. The self-pressurizing glenoid component had 0.005% radiographic radiolucent lines, and the traditional glenoid component had 45% radiographic radiolucent lines, with 38% of the radiolucencies in the traditional glenoid component group being defined as grade E. There were no progressive radiolucencies, differences in clinical outcomes, or complications at 2 years postoperatively.

CONCLUSION

In the fully cemented condition, the 2 component designs had comparable performance; however, the differences in designs could be better observed in the uncemented group. The self-pressurizing all-polyethylene design studied has superior biomechanical stability. Clinically, the improved stability of the glenoid component correlated with a reduction of radiolucent lines and will likely lead to a reduction in glenoid component loosening.

Reverse total shoulder arthroplasty baseplate stability with locking vs. non-locking peripheral screws

BACKGROUND

There are many options for glenosphere baseplate fixation commercially available, yet there is little biomechanical evidence supporting one type of fixation over another. In this study, we compared the biomechanical fixation of a reverse total shoulder glenoid baseplate secured with locking or non-locking peripheral screws.

METHODS

Both a non-augmented mini baseplate with full backing support and an augmented baseplate were testing after implantation in solid rigid polyurethane foam. Each baseplate was implanted with a 30 mm central compression screw and four peripheral screws, either locking or non-locking (15 mm anterior/posterior and 30 mm superior/inferior). A 1 Hz cyclic force of 0-750 N was applied at a 60^o angle for 5000 cycles. Throughout the test, the displacement of the baseplate was measured using a 3D Digital Image Correlation System.

FINDINGS

The amount of migration measured in the both the non-augmented and augment cases shows no significant differences between locking and non-locking cases at the final cycle count (non-augment: 5.66 +/- 2.29 μm vs. 3.71 +/- 1.23 μm; p = 0.095, augment: 15.43 +/- 8.49 μm vs. 12.46 +/- 3.24 μm; p = 0.314). Additionally, the amount of micromotion measured for both sample types shows the same lack of significant difference (non-augment: 10.79 +/- 5.22 μm vs. 10.16 +/- 7.61 μm; p = 0.388, augment: 55.03 +/- 10.13 μm vs. 54.84 +/- 10.65 μm; p = 0.968).

INTERPRETATION

The presence of locking versus non-locking peripheral screws does not make a significant difference on the overall stability of a glenoid baseplate, in both a no defect case with a non-augmented baseplate and a bone defect case with an augmented baseplate.

Anatomic Total Shoulder Arthroplasty: Component Size Prediction with 3-Dimensional Pre-Operative Digital Planning

Background

The rate, complexity, and cost of total shoulder arthroplasty (TSA) continues to grow. Technology has advanced pre-operative templating. Reducing cost of TSA has positive impact for the patient, manufacturer, and hospital. The aim of this study was to evaluate the accuracy of implant size selection based on 3-D templating. Our hypothesis was that pre-operative templating would enable accurate implant prediction within one size.

Methods

Multicenter retrospective study of anatomic TSAs templated utilizing 3-D virtual planning technology. This program uses computed tomography (CT) scans allowing the surgeon to predict component sizes of the glenoid and humeral head and stem. Pre-operative templated implant size were compared to actual implant size at the time of surgery. Primary data analysis utilized unweighted Cohen's Kappa test.

Results

111 TSAs were analyzed from five surgeons. Pre-operative templated glenoid sizes were within one size of actual implant in 99% and exactly matched in 89%. For patients requiring a posterior glenoid augment (n = 14), 100% of implants were within one size of the template and 93% matched exactly. For stemless humeral components (n = 87) implanted, 98% matched the pre-operative template within one size with 79% exactly matched. For stemmed components (n = 24), 88% of cases were within one size of the preoperative plan and exactly matching in 83%. Humeral head diameter matched within one size of the pre-operative template in 84% of cases and exactly matched in 72%.

Conclusion

Pre-operative 3-D templating for TSAs can accurately predict glenoid and humeral component size. This study sets the groundwork for utilization of pre-operative 3-D templating as a potential method to reduce overall TSA costs by managing cost of implants, reducing inventory needs, and improving surgical efficiency.

Preoperative Factors Associated with Patient Satisfaction Two Years After Elective Shoulder Surgery

Background Purpose

Patient satisfaction has become an increasingly important component of quality measures for both hospital reimbursement and quality assessment. Additionally, patient satisfaction influences patient behavior and patient follow-up. The purpose of this study was to identify preoperative factors associated with patient satisfaction 2 years after shoulder surgery.

Methods

Electronic surveys were used to collect patient information including demographic, surgical, and social history, as well as outcome data. Satisfaction was measured 2 years after surgery using the Surgical Satisfaction Questionnaire.

Results

Multivariable linear regression identified preoperative Patient-Reported Outcomes Measurement Information System Pain Interference, annual income, and American Society of Anesthesiologists score as independent predictors of lower patient satisfaction, while total shoulder arthroplasty was an independent predictor of greater patient satisfaction. The model accounted for 15% of the variance in satisfaction scores (R² = 0.15).

Conclusion

Patient satisfaction 2 years after shoulder surgery is associated with preoperative patient-reported outcome scores. Lower patient satisfaction is independently predicted by greater preoperative PROMIS PI, income less than $70,000, and ASA score >1, while higher patient satisfaction is predicted by total shoulder arthroplasty.

Postoperative stiffness after reverse total shoulder arthroplasty

PURPOSE

The purpose of this study was to evaluate the rate and risk factors for stiffness after reverse shoulder arthroplasty and the ramifications on the patient-reported outcomes.

METHOD

A consecutive series of patients who underwent reverse shoulder arthroplasty were prospectively followed for one year. Passive range of motion was measured preoperatively and at regular intervals postoperatively. Patients with passive forward elevation of less than 100° or passive external rotation of less than 30° were defined as stiff. Radiographic parameters and postoperative patient-reported outcome scores were collected.

RESULTS

Seventy-six patients were available for review. The prevalence of postoperative stiffness following reverse shoulder arthroplasty was 47% at three months, 31% at six months, and 25% at one year. Preoperative shoulder stiffness was associated with three-month postoperative stiffness only. In patients with one-year stiffness, smaller (p = 0.03) and less lateralized glenospheres (p = 0.024) were more common. Stiffness was not associated with one-year patient-reported outcome scores.

CONCLUSION

Stiffness is common after reverse shoulder arthroplasty and often improves at one-year after surgery. Implant design and selection may be important determinants of passive range of motion. While stiffness does not appear to influence patient-reported outcome scores, one of four patients will potentially have stiffness one year following reverse shoulder arthroplasty.Level of evidence: Level III; retrospective study.

Three dimensional patient-specific guides for guide pin positioning in reverse shoulder arthroplasty: An experimental study on different glenoid types

INTRODUCTION

Incorrect positioning is one of the main factors for glenoid component loosening in reverse shoulder arthroplasty and component placement can be challenging. This study aimed to assess whether Patient-Specific Instrumentation (PSI) provides better guide pin positioning accuracy and is superior to standard guided and freehand instrumentation methods in cases of glenoid bone deformity.

MATERIALS AND METHODS

Based on the Walch classification, five different scapula types were acquired by computed tomography (CT). For each type, two different surgeons placed a guide pin into the scapula using three different methods: freehand method, conventional non-patient-specific guide, and PSI guide. Each method was repeated five times by both surgeons. In these experiments, a total of 150 samples of scapula models were used (5 × 2 × 3 × 5 = 150). Post-operative CT scans of the samples with the guide pin were digitally assessed and the accuracy of the pin placement was determined by comparison to the preoperative planning on a three-dimensional (3D) model.

RESULTS

The PSI method showed accuracies to the preoperative plan of 2.68 (SD 2.10) degrees for version angle (p < .05), 2.59 (SD 2.68) degrees for inclination angle (p < .05), and 1.55 (SD 1.26) mm for entry point offset (p < .05). The mean and standard deviation errors compared to planned values of version angle, inclination angle, and entry point offset were statistically significant for the PSI method for the type C defected glenoid and non-arthritic glenoid.

CONCLUSION

Using the PSI guide created by an image processing software tool for guide pin positioning showed advantages in glenoid component positioning over other methods, for defected and intact glenoid types, but correlation with clinical outcomes should be examined.

Limited value of current shoulder arthroplasty registries in evidence-based shoulder surgery: a review of 7 national registries

National shoulder arthroplasty registries are currently used to assess incidence, indication, type of prosthesis and revision, but they seem to lack sufficient information to lead to evidence based decision-making in shoulder surgery. There appears to be a large difference in registered parameters and outcome measurement per country. First we investigated whether existing registries have sufficient common datasets to enable pooling of data. Second, we determined whether known risk factors for prosthetic failure are being recorded. Through a non-systematic literature review studies on registries were analyzed for included parameters. Seven national registries were scrutinized for the data collected and these were classified according to categories of risk factors for failure: patient-, implant and surgeon related, and other parameters. This shows a large heterogeneity of registered parameters between countries. The majority of parameters shown to be relevant to outcome and failure of shoulder prostheses are not included in the studied registries. International agreement on parameters and outcome measurement for registries is paramount to enable pooling and comparison of data. If we intend to use the registries to provide us with evidence to improve prosthetic shoulder surgery, we need adjustment of the different parameters to be included.

When should reverse total shoulder arthroplasty be considered in glenohumeral joint arthritis?

Anatomical total shoulder arthroplasty (TSA) has been used widely in treatment of glenohumeral osteoarthritis and provides excellent pain relief and functional results. Reverse total shoulder arthroplasty (RSA) was created to treat the complex problem of rotator cuff tear arthropathy. RSA also has been performed for glenohumeral osteoarthritis even in cases where the rotator cuff is preserved and has shown good results comparable with TSA. The indications for RSA are expanding to include tumors of the proximal humerus, revision of hemiarthroplasty to RSA, and revision of failed TSA to RSA. The purposes of this article were to describe comprehensively the conditions under which RSA should be considered in glenohumeral osteoarthritis, to explain its theoretical background, and to review the literature.

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.

Glenoid Radiolucent Lines in Anatomic Total Shoulder Arthroplasty are Unaffected by Thrombin Glenoid Preparation

Background

Modern glenoid cementing techniques for anatomic total shoulder arthroplasty has improved the ability to achieve a stable cement mantle, but the efficacy of adjunctive agents in glenoid preparation is unclear. The purpose of this study is to compare the early radiolucency rates of glenoids prepared with and without thrombin.

Methods

We identified patients between January 2017 and February 2019 undergoing primary anatomic TSA using two glenoid types. Group A glenoids had a cemented central peg without peripheral peg cementation, and Group B glenoids had cemented peripheral pegs without central peg cementation. The first postoperative radiograph was assessed for radiolucent lines. All patients had the same glenoid preparation except some had the addition of thrombin as a preparation agent.

Results

We identified 83 Group A glenoids with and 63 without thrombin glenoid preparation, and109 Group B glenoids with and 48 without thrombin preparation. All Group A glenoids had no radiolucent lines and 5 (3%) Group B glenoids had radiolucent lines. Use of thrombin showed no difference in early radiolucencies (p=1.00) in either Group.

Conclusion

The addition of thrombin as a preparation agent had no effect on early glenoid radiolucent lines in anatomic TSA, and its routine use should be reconsidered.

Initial Assessments of a Handheld Indentation Probe's Correlation With Cancellous Bone Density, Stiffness, and Strength: An Objective Alternative to “Thumb Testing”

Objective: During shoulder arthroplasty, surgeons must select the optimal implant for each patient. The metaphyseal bone properties affect this decision; however, the typical resection “thumb test” lacks objectivity. This investigation's purposes were to determine the correlation strength between the indentation depth of a handheld mechanism and the density, compressive strength, and modulus of a bone surrogate; as well as to assess how changing the indenter tip shape and impact energy may affect the correlation strengths. Methods: A spring-loaded indenter was developed. Four tip shapes (needle, tapered, flat, and radiused cylinders) and four spring energies (0.13 J–0.76J) were assessed by indenting five cellular foam bone surrogates of varying density, every five times. After each indentation, the indentation depth was measured with a separate probe and correlated with manufacturer specifications of the apparent density, compressive strength, and modulus. Results: indentation depth plateaued as the bone surrogate's material properties increased, particularly for indentation tips with larger footprints and the 0.13 J spring. All tip shapes produced strong (R2≥0.7) power-law relationships between the indentation depth metric and the bone surrogate's material properties (density: 0.70 ≤ R2 ≤ 0.95, strength: 0.75 ≤ R2 ≤ 0.97, modulus: 0.70 ≤ R2 ≤ 0.93); though the use of the needle tip yielded the widest indentation depth scale. Interpretation: these strong correlations suggest that a handheld indenter may provide objective intra-operative evidence of cancellous material properties. Further investigations are warranted to study indenter tip shape and spring energy in human tissue; though the needle tip with spring energy between 0.30 J and 0.76 J seems the most promising.

Two-year results of a multi-centre, randomized controlled trial comparing a second-generation uncemented trabecular metal-backed versus cemented polyethylene glenoid component in total shoulder arthroplasty

Aims

To report early (two-year) postoperative findings from a randomized controlled trial (RCT) investigating disease-specific quality of life (QOL), clinical, patient-reported, and radiological outcomes in patients undergoing a total shoulder arthroplasty (TSA) with a second-generation uncemented trabecular metal (TM) glenoid versus a cemented polyethylene glenoid (POLY) component.

Methods

Five fellowship-trained surgeons from three centres participated. Patients aged between 18 and 79 years with a primary diagnosis of glenohumeral osteoarthritis were screened for eligibility. Patients were randomized intraoperatively to either a TM or POLY glenoid component. Study intervals were: baseline, six weeks, six-, 12-, and 24 months postoperatively. The primary outcome was the Western Ontario Osteoarthritis Shoulder QOL score. Radiological images were reviewed for metal debris. Mixed effects repeated measures analysis of variance for within and between group comparisons were performed.

Results

A total of 93 patients were randomized (46 TM; 47 POLY). No significant or clinically important differences were found with patient-reported outcomes at 24-month follow-up. Regarding the glenoid components, there were no complications or revision surgeries in either group. Grade 1 metal debris was observed in three (6.5%) patients with TM glenoids at 24 months but outcomes were not negatively impacted.

Conclusion

Early results from this RCT showed no differences in disease-specific QOL, radiographs, complication rates, or shoulder function between uncemented second-generation TM and cemented POLY glenoids at 24 months postoperatively. Revision surgeries and reoperations were reported in both groups, but none attributed to glenoid implant failure. At 24 months postoperatively, Grade 1 metal debris was found in 6.5% of patients with a TM glenoid but did not negatively influence patient-reported outcomes. Longer-term follow-up is needed and is underway.

Cite this article: Bone Jt Open 2021;2(9):728–736.

Shoulder Hemiarthroplasty with Nonprosthetic Glenoid Arthroplasty: The Ream-and-Run Procedure

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Glenoid component wear and loosening are the principal failure modes of anatomic total shoulder arthroplasty (aTSA).

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The ream-and-run (RnR) procedure is an alternative glenohumeral arthroplasty for patients who wish to avoid the risks and limitations of a prosthetic glenoid component.

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During the RnR procedure, the arthritic glenoid is conservatively reamed to a single concavity, while the prosthetic humeral component and soft tissues are balanced to provide both mobility and stability of the joint.

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The success of the RnR procedure depends on careful patient selection, preoperative education and engagement, optimal surgical technique, targeted rehabilitation, and close postoperative communication between the surgeon and the patient.

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While the RnR procedure allows high levels of shoulder function in most patients, the recovery can be longer and more arduous than with aTSA.

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Patients who have undergone an RnR procedure occasionally require a second closed or open procedure to address refractory shoulder stiffness, infection, or persistent glenoid-sided pain. These second procedures are more common after the RnR than with aTSA.

Trends and impact of three-dimensional preoperative imaging for anatomic total shoulder arthroplasty

BACKGROUND

The goals of this study were to determine the incidence in the United States of preoperative three-dimensional imaging prior to anatomic total shoulder arthroplasty for osteoarthritis and to determine if preoperative imaging is associated with decreased complication rates.

METHODS

Using a Medicare insurance database, we identified all patients who underwent computed tomography (n = 9380) and/or magnetic resonance imaging (n = 15,653) prior to anatomic total shoulder arthroplasty for a diagnosis of osteoarthritis from 2005 to 2014. The incidence of imaging over time was analyzed and complication rates compared between patients with imaging to matched controls.

RESULTS

The incidence of preoperative three-dimensional imaging significantly increased over time, with computed tomography increasing more than magnetic resonance imaging. Compared to controls, patients with preoperative computed tomography imaging had significantly lower revision rates at two years (odds ratio 0.72 (0.64-0.82), p = 0.008). There were no other significant differences in the other complications studied.

CONCLUSIONS

The use of preoperative three-dimensional imaging for anatomic total shoulder arthroplasty for a diagnosis of osteoarthritis has increased dramatically, with the use of computed tomography increasing the most. Patients who underwent preoperative computed tomography imaging experienced lower revision rates at two years postoperatively compared to matched controls without such imaging.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Regional apparent density correlations within the proximal humerus

Background

Bone quality influences humeral implant selection for shoulder arthroplasty. However, little is known about how well bone near the humeral resection represents more distal cancellous bone. This investigation aimed to quantify the correlations between the apparent density of sites near the humeral head resection plane and cancellous sites throughout the metaphysis.

Methods

Using computed tomography data from 98 subjects, apparent bone density was quantified in 65 regions throughout the proximal humerus. Pearson's correlation coefficient was determined comparing the density between samples from the humeral resection and all supporting regions beneath the resection. Mean correlation coefficients were compared for (i) each sample region with all support regions, (ii) pooling all sample regions within a slice, and (iii) considering sample regions correlated with only the support regions in the same anatomic section.

Results

Stronger correlations existed for bone sampled beneath the resection (0.33 ± 0.10≤ r ≤ 0.88 ± 0.10), instead of from the resected humeral head (0.22 ± 0.10≤ r ≤ 0.66 ± 0.14). None of sample region correlated strongly with all support regions; however, strong correlations existed when sample and support regions both came from the same anatomic section.

Discussion

Assessments of cancellous bone quality in the proximal humerus should be made beneath the humeral resection not in the resected humeral head; and each anatomic quadrant should be assessed independently.

Variability in total shoulder arthroplasty planning software compared to a control CT-derived 3D printed scapula

BACKGROUND

Two techniques exist from which all 3D preoperative planning software for total shoulder arthroplasty are based. One technique is based on measurements constructed on the mid-glenoid and scapular landmarks (Landmark). The second is an automated system using a best-fit sphere technique (Automated). The purpose was to compare glenoid measurements from the two techniques against a control computed tomography-derived 3D printed scapula.

METHODS

Computed tomography scans of osteoarthritic shoulders of 20 patients undergoing primary total shoulder arthroplasty were analyzed with both 3D planning software techniques. Measurements from a 3D printed scapula (Scapula) from the true 3D computed tomography scan served as controls. Glenoid version and inclination measurements from each group were blinded and reviewed.

RESULTS

In 65% (Automated) and 45% (Landmark) of cases, either inclination or version varied by 5° or more versus 3D printed scapula. Significant variability in version differences compared to the scapula group existed (p = 0.007). Glenoid version from the Scapula = 13.0° ± 10.6°, Automated = 15.0° ± 13.9°, and Landmark = 12.2° ± 7.8°. Inclination from Scapula = 5.4° ± 7.9°, Automated = 6.1° ± 12.6°, and Landmark = 6.2° ± 9.1°.

DISCUSSION

A high percentage of cases showed discrepancies in glenoid inclination and version values from both techniques. Surgeons should be aware that regardless of software technique, there is variability compared to measurements from a control 3D computed tomography printed scapula.

Does computerized CT-based 3D planning of the humeral head cut help to restore the anatomy of the proximal humerus after stemless total shoulder arthroplasty?

BACKGROUND

Restoration of proximal humeral anatomy (RPHA) after total shoulder arthroplasty (TSA) has been shown to result in better clinical outcomes than is the case in nonanatomic humeral reconstruction. Preoperative virtual planning has mainly focused on glenoid component placement. Such planning also has the potential to improve anatomic positioning of the humeral head by more accurately guiding the humeral head cut and aid in the selection of anatomic humeral component sizing. It was hypothesized that the use of preoperative 3-dimensional (3D) planning helps to reliably achieve RPHA after stemless TSA.

METHODS

One hundred consecutive stemless TSA (67 males, 51 right shoulder, mean age of 62 ±9.4 years) were radiographically assessed using pre- and postoperative standardized anteroposterior radiographs. The RPHA was measured with the so-called circle method described by Youderian et al. We measured deviation from the premorbid center of rotation (COR), and more than 3 mm was considered as minimal clinically important difference. Additionally, pre- and postoperative humeral head diameter (HHD), head-neck angle (HNA), and humeral head height (HHH) were measured to assess additional geometrical risk factors for poor RPHA.

RESULTS

The mean distance from of the premorbid to the implanted head COR was 4.3 ± 3.1 mm. Thirty-five shoulders (35%) showed a deviation of less than 3 mm (mean 1.9 ±1.1) and 65 shoulders (65%) a deviation of ≥3 mm (mean 8.0 ± 3.7). Overstuffing was the main reason for poor RPHA (88%). The level of the humeral head cut was responsible for overstuffing in 46 of the 57 overstuffed cases. The preoperative HHD, HHH, and HNA were significantly larger, higher, and more in valgus angulation in the group with accurate RPHA compared with the group with poor RPHA (HHD of 61.1 mm ± 4.4 vs. 55.9 ± 6.6, P < .001; HHH 8.6±2.2 vs. 7.6±2.6, P = .026; and varus angulation of 134.7° ±6.4° vs. 131.0° ±7.91, P = .010).

CONCLUSION

Restoration of proximal humeral anatomy after stemless TSA using computed tomography (CT)-based 3D planning was not precise. A poorly performed humeral head cut was the main reason for overstuffing, which was seen in 88% of the cases with inaccurate RPHA. Preoperative small HHD, low HHH, and varus-angulated HNA are risk factors for poor RPHA after stemless TSA.

Value Analysis of Anatomic and Reverse Shoulder Arthroplasty for Glenohumeral Osteoarthritis with an Intact Rotator Cuff

BACKGROUND

While anatomic total shoulder arthroplasty (TSA) has historically been considered the ideal treatment for end-stage glenohumeral osteoarthritis, reverse shoulder arthroplasty (RSA) has recently gained popularity. With substantial differences in implant design and cost between TSA and RSA, further investigation of outcomes and value is needed to support recent trends. The purpose of this study was to use the average and incremental cost-effectiveness ratio (ACER and ICER) and the procedure value index (PVI) to examine differences in outcomes and value between TSA and RSA for treatment of glenohumeral osteoarthritis with an intact rotator cuff.

METHODS

We performed a retrospective matched-cohort study of patients treated with primary shoulder arthroplasty for osteoarthritis with an intact rotator cuff who had a minimum 2-year follow-up. Outcome measures analyzed included the Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons (ASES) questionnaire, visual analog scale (VAS) for pain, Single Assessment Numeric Evaluation (SANE), and overall satisfaction. Patients treated with TSA were matched 4:1 to those treated with RSA based on sex, age, and preoperative SST score. Value differences between TSA and RSA were calculated. Radiographs were analyzed for preoperative glenoid classification and postoperative radiolucent lines and gross loosening.

RESULTS

Two hundred and fifty-two TSA-treated patients were matched to 63 RSA-treated patients with no significant differences in sex, age, or preoperative SST score. Total hospitalization costs, charges, and reimbursements along with outcome improvements in units of minimal clinically important differences (MCIDs) and patient satisfaction did not differ between the groups. For RSA, the implant cost was significantly higher than that for TSA, but the operating room, anesthesia, and cement costs were lower. The TSA group had a 3.2% rate of gross glenoid loosening and a 2.4% revision rate. There was no loosening or revision in the RSA group. None of the value analytics differed between groups even after inclusion of the outcomes and costs of early TSA revisions.

CONCLUSIONS

TSA and RSA demonstrated similar outcomes and value when used to manage glenohumeral osteoarthritis with an intact rotator cuff.

LEVEL OF EVIDENCE

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

The study of 2-dimensional computed tomography scans of the glenoid anatomy in relation to reverse shoulder arthroplasty in the Southern Chinese population

Background

Reverse shoulder arthroplasty is becoming an increasingly common surgical procedure in Hong Kong, as well as in many other countries worldwide. The aim of this study is to describe the glenoid anatomy in the Southern Chinese population. We are interested to know whether commercially available glenoid implants are suitable for this population and whether there are any steps or precautions we can take during surgery to optimize the clinical outcome for these patients.

Method

A total of 244 shoulders of Southern Chinese patients were analyzed using 2-dimensional computed tomography, formatted to align along the scapular axis. The anatomic parameters analyzed included the shape, axial configuration, maximum width, maximum height, version, and presence of bone defect.

Results

In our study, 76.6% of glenoids were pear-shaped, 23.0% were elliptical, and only 0.4% were inverted pear in shape. Of all glenoids, 95.1% of glenoids had posterior-prominent axial configuration, whereas 4.9% had neutral axial configuration. The mean maximum glenoid height for both genders was 33.8 mm, whereas the mean maximum glenoid height was 32.2 mm for women and 36.6 mm for men. The mean maximum glenoid width for both genders was 25.8 mm, whereas the mean maximum glenoid width was 24.8 mm for women and 27.3 mm for men. The differences in measurements between genders were statistically significant. Of all glenoids, 46.3% of the glenoids were retroverted, whereas 53.7% of the glenoids were anteverted. The mean version for both genders was 0.77 degrees anteversion. The mean version was 1.16 degrees anteversion for women and 0.10 degrees anteversion for men. Of the 244 glenoids, 4 had bone defects. In our study, 39.8% of patients had mean maximum glenoid widths that were less than 25 mm, which is the smallest size available for most conventional glenoid baseplates.

Conclusion

A significant portion of the Southern Chinese population has glenoid widths that are smaller than the smallest commercially available glenoid baseplates. Understanding the glenoid anatomy is crucial in the case of reverse shoulder arthroplasty, as it has significant implications in implant design, operative planning, and surgical outcomes.

Medium to long-term results of a recessed glenoid for glenoid resurfacing in total shoulder arthroplasty

BACKGROUND

Recessed mini-glenoid components provide an alternative to total shoulder replacement that may avoid some of the known shortcomings and complications associated with shoulder hemiarthroplasty or standard glenoid components in difficult cases. This study reports survivorship, radiological and clinical outcomes of a recessed mini-glenoid implant in a consecutive cohort.

METHODS

Retrospective cohort study reporting outcomes of 28 consecutive shoulders (27 patients) following total shoulder replacement using a recessed, cemented mini-glenoid implant at two sites.

RESULTS

The most frequent diagnosis was primary osteoarthritis (79%); glenoid morphology was Walch Type A (67%), B1 15%, B2 10% and C 10%. At final follow-up, pain was 16.3 (SD = 23.1), American Shoulder and Elbow Score was 64.5 (SD = 31.9) and (normalized) Constant score was 83.0 (SD = 20.7). Implant survivorship at average final follow-up of seven years (3-13) was 96.4%. Seven mini-glenoids showed small peripheral radiolucent lines at one-year X-ray follow-up but were non-progressive on subsequent imaging.

DISCUSSION

Recessed polyethylene mini-glenoid is an attractive alternative for shoulder arthroplasty and provides an intermediate solution between standard glenoid components and hemiarthroplasty. Our medium to long-term results demonstrate reliable clinical outcomes, absence of glenoid erosion, low complication rate and satisfactory implant survivorship.

Software simulations of changing offsets and thus soft tissue tension when revising anatomic to reverse total shoulder arthroplasty in convertible platform systems

BACKGROUND

Revision shoulder arthroplasty may involve the need to remove a well-fixed humeral stem. To avoid this, convertible platform systems have been introduced. The biomechanics of reverse total shoulder arthroplasty (rTSA) differs from anatomic shoulder arthroplasty (aTSA). The different humeral osteotomy and soft tissue tension may jeopardize the optimal results of the converted rTSA. The aim was to evaluate the radiographic parameters of soft tissue distraction when converting an aTSA to rTSA in a platform system and assess the capability of conversion without "over-stuffing" the shoulder in the "best-case scenario".

METHODS

Radiographic analysis of soft tissue distraction parameters: difference in acromio-humeral distance, difference in lateral humeral offset and difference in latero-inferior displacement were evaluated in aTSA and in the converted rTSA in six different implants. Image analysing software was used on 10 non-deformed osteoarthritic shoulder X-rays to simulate conversion.

RESULTS

The greatest increase in arm length was found for Tornier Ascend Flex (26.8 ± 3.6 mm) while the smallest increase was observed with Lima SMR (19.3 ± 4 mm). The humerus remained most lateralized with the Zimmer Anatomical/Inverse ( - 1.4 ± 2.9 mm) while Lima SMR ( - 15.8 ± 2.7 mm) was more medialized. The greatest increase in latero-inferior distance was found in the onlay systems. A group analysis of onlay rTSA showed an increase of 46% in arm length (p < 0.0001), 83% larger humeral offset (p < 0.0001) and 144% increase in latero-inferior distraction (p < 0.0001) when compared to inlay rTSA.

CONCLUSION

The conversion of aTSA to rTSA using a convertible platform system may lead to significant increase in radiographic parameters corresponding to soft tissue tension. This may alter the biomechanics, restrict the convertibility or jeopardize the optimal clinical outcome of rTSA even in the best-case scenario.

Arthroscopic Evaluation and Treatment of Complications That Arise Following Prosthetic Shoulder Arthroplasty

Arthroscopy may be used to diagnose symptomatic glenoid loosening following anatomic total shoulder arthroplasty (aTSA), and arthroscopic glenoid component removal may suffice as treatment for some patients. Arthroscopy may be used to diagnose shoulder prosthetic joint infection (PJI) following aTSA and reverse shoulder arthroplasty (RSA). Tissues are biopsied from multiple sites within the joint and the subdeltoid or subacromial space, and they are cultured for a minimum of 14 days. Postoperative adhesions arising after prosthetic shoulder arthroplasty (PSA) may be released arthroscopically. However, other problems contributing to shoulder stiffness such as component malpositioning or shoulder PJI require additional intervention. Arthroscopy may be used to repair select rotator cuff tears that arise acutely following aTSA, but chronic attritional tears do not heal after repair; therefore, revision to RSA often is needed. Many complications following PSA, such as infection, fixed instability, humeral component loosening, and major humeral or glenoid bone loss, are not adequately treated using arthroscopic techniques. However, arthroscopy following PSA may help to diagnose and treat other complications, even as the precise indications following aTSA and RSA remain unclear.

Hemiarthroplasties: the choice of prosthetic material causes different levels of damage in the articular cartilage

BACKGROUND

Hemiarthroplasty has clear advantages over alternative procedures and is used in 20% of all shoulder joint replacements. Because of cartilage wear, the clinical outcome of hemiarthroplasty is unreliable and controversial. This paper suggests that the optimal choice of prosthetic material may reduce cartilage degeneration and improve the reliability of the procedure. The specific objectives were to assess 3 materials and assess how the severity of arthritis might affect the choice of prosthetic material.

METHODS

A CoCr alloy, an AL₂O₃ ceramic, and a polycarbonate urethane polymer (PCU) were mechanically tested against 5 levels of human osteoarthritic cartilage (from intact to severely arthritic, n = 45). A high friction coefficient, a decrease in Young's modulus, an increase in permeability, a decrease in relaxation time, an increase in surface roughness, and a disrupted appearance of the cartilage after testing were used as measures of cartilage damage. The biomaterial that caused minimal cartilage damage was defined as superior.

RESULTS

The CoCr caused the most damage. This was followed by the AL₂O₃ ceramic, whereas the PCU caused the least amount of damage. Although the degree of arthritis had an effect on the results, it did not change the trend that CoCr performed worst and PCU the best.

DISCUSSION AND CONCLUSION

This study indicates that ceramic implants may be a better choice than metals, and the articulating surface should be as smooth as possible. Although our results indicate that the degree of arthritis should not affect the choice of prosthetic material, this suggestion needs to be further investigated.

Radiographic performance depends on the radial glenohumeral mismatch in total shoulder arthroplasty

BACKGROUND

Optimal radii of curvature of the articulating surfaces of the prosthetic components are factors associated with the longevity of cemented glenoid components in anatomical total shoulder arthroplasty. It was the purpose of this study, to evaluate the radiographic and clinical performance of an anatomical glenoid component of a total shoulder arthroplasty (TSA) with respect to radial mismatch of the glenoid and humeral component.

METHODS

In a retrospective study 75 TSA were analyzed for their clinical and radiographic performance with computed tomography by independent examiners using an established methodology. The study group was divided in two groups, one with mismatch < 4.5 mm (n:52) the others with mismatch ≥4.5 mm (n:23) and analyzed for confounding variables as indication, primary or revision surgery, age, gender, glenoid morphology and implant characteristics.

RESULTS

The mean glenohumeral radial mismatch was 3.4 mm (range 0.5-6.9). At median follow-up of 41 months (range 19-113) radiographic loosening (defined as modified Molé scores ≥6) was present in 7 cases (9.3%). Lucencies around the glenoid pegs (defined as modified Molé score ≥ 1) were present in 34 cases (45%). Radiolucencies were significantly associated with a radial mismatch < 4.5 mm (p = 0.000). The pre- to postoperative improvements in Subjective Shoulder Value and absolute Constant Score were significantly better in the group with a mismatch ≥4.5 mm (p = 0.018, p = 0.014).

CONCLUSION

A lower conformity of the radii of humerus and glenoid seems to improve the loosening performance in TSA. Perhaps cut-off values regarding the recommended mismatch need to be revalued in the future.

Rehabilitation After Anatomic and Reverse Total Shoulder Arthroplasty: A Critical Analysis Review

Postoperative rehabilitation is believed to be essential in optimizing clinical outcome and function following shoulder arthroplasty. Despite this long-held notion, there is a paucity of high-quality evidence to guide rehabilitation protocols and practice. For patients undergoing anatomic total shoulder arthroplasty (ATSA), there are insufficient comparative data regarding type or duration of sling utilization. Based on current evidence, there is no appreciable benefit to early motion compared with a delayed-motion protocol following ATSA. There is insufficient literature to support the use of formal physical therapy over a physician-directed program following ATSA. At the present time, no high-quality evidence exists to guide the postoperative rehabilitation of patients undergoing reverse total shoulder arthroplasty (RTSA). Prospective randomized controlled trials evaluating postoperative management and rehabilitation following ATSA and RTSA are needed to guide best practices and optimize clinical outcomes.

Humeral Retroversion (Complexity of Assigning Reference Axes in 3D and Its Influence on Measurement): A Technical Note

Background

Humeral retroversion (RV) is important to the study of shoulder function and reconstruction. This study tests the hypothesis that clinically obtained computer tomography (CT) measurements for humeral RV (off-axis measurements) differ from those obtained after reformatting the image slice orientation so that the humeral shaft is perpendicular to the gantry (coaxial measurements) and explores deviations from true RV.

Materials and methods

A custom-built application created in Mathematica was used to explore the effect of altering the humeral orientation on slice angle acquisition by 3D imaging technologies, on the perceived angle of RV from the 2D-projection of the reference axes. The application allows for control of humeral axis orientation relative to image slice (3D) or plain of projection (2D) and humeral rotation. The effect of rotating a virtual model of one humerus around its own axis and in discrete anatomical directions on the measured RV angle was assessed.

Results

The coaxial measurement of humeral RV (31.2°) differed from off-axis measurement, with a maximum difference in measured RV of 50° in 45° of extension. The typical position of the humerus in a CT scan resulted in a difference in RV measurement up to 22°. Explorations of deviation led to the following outcomes, as divided by anatomic direction. Extension and abduction led to an underestimation, and flexion and adduction led to an overestimation of the RV-angle.

Conclusion

Measurements must be done consistently about the position and orientation of the humerus. Deviation in the humeral alignment of as little as 10° can distort the measurement of version up to 15°.

How to cite this article

van de Bunt F, Pearl ML, van Noort A. Humeral Retroversion (Complexity of Assigning Reference Axes in 3D and Its Influence on Measurement): A Technical Note. Strategies Trauma Limb Reconstr 2020;15(2):69-73.

Risk factors for and timing of adverse events after revision total shoulder arthroplasty

BACKGROUND

Despite increasing rates of revision total shoulder arthroplasty (RTSA), there is a paucity of literature on optimizing perioperative outcomes. The purposes of this study were to identify risk factors for unplanned readmission and perioperative complications following RTSA, risk-stratify patients based on these risk factors, and assess timing of complications.

METHODS

Bivariate and multivariate analyses of risk factors were assessed on RTSA patients from the ACS-NSQIP database from 2011 to 2015. Patients were risk-stratified and timing of severe adverse events and cause of readmission were evaluated.

RESULTS

Of 809 RTSA patients, 61 suffered a perioperative complication or readmission within 30 days of discharge. Multivariate analysis identified operative time, BMI > 40, infection etiology, high white blood cell count, and low hematocrit as significant independent risk factors for 30-day complications or readmission after RTSA (p ≤ 0.05). Having at least one significant risk factor was associated with 2.71 times risk of complication or readmission within 15 days compared to having no risk factors (p < 0.001). The majority of unplanned readmission, return to the operating room, open/deep wound infection, and sepsis/septic shock occurred within two weeks of RTSA.

DISCUSSION

Patients at high risk of complications and readmission after RTSA should be identified and optimized preoperatively to improve outcomes and lower costs.

Accuracy of patient-specific instrumentation in shoulder arthroplasty: a systematic review and meta-analysis

Background

There has been significant recent emphasis on the use of patient-specific instrumentation (PSI) in shoulder arthroplasty. However, clinical data are lacking to support the increased time and expense associated with PSI. Our purposes were to determine whether PSI significantly improves implantation accuracy during total shoulder arthroplasty (TSA) and to analyze available techniques and correlation with clinical outcomes. We hypothesized that PSI may improve glenoid component position radiographically but without correlation with clinical outcomes.

Methods

The MEDLINE, Scopus, Embase, and Cochrane Library databases were queried. Included articles reported use of any preoperative or intraoperative PSI techniques, models, or guides to assist with TSA prosthesis implantation. The primary outcomes were mean deviation from the preoperative plan in version (in degrees), inclination (in degrees), and entry-point offset on the glenoid (in millimeters).

Results

Among the included articles, 518 TSA procedures (352 anatomic and 166 reverse) were performed. The mean postoperative errors in both version and inclination angles were 5° or less in 20 articles (90.9%) using PSI. Meta-analysis revealed no statistically significant differences in version error (P > .999, I ² = 64.6%), inclination error (P = .702, I ² = 82.2%), or positional offset (P = .777, I ² = 85.7%) between PSI and standard instrumentation. No data regarding patient-reported outcome measures, range of motion, strength, or glenoid component loosening and longevity were reported.

Conclusions

Meta-analysis revealed no significant differences in accuracy between PSI and standard instrumentation. Although PSI may possess the potential to improve TSA techniques, further investigations regarding long-term clinical outcomes, impact on operating room time, and cost-effectiveness are warranted before PSI can be routinely recommended over conventional instrumentation.

3D preoperative planning for humeral head selection in total shoulder arthroplasty

BACKGROUND

Recreation of glenohumeral biomechanics and humeral anatomy has been shown to improve outcomes in shoulder arthroplasty. Recent research has focused on utilizing simulation software and intraoperative instrumentation to improve glenoid implant selection and positioning, but no study had evaluated the reliability of new features in 3D preoperative planning software for humeral planning in total shoulder arthroplasty.

MATERIALS AND METHODS

Preoperative plans were created for 26 patients using three different simulation software programs: an independent preoperative planning simulation (IPPS) software (OrthoVis) and two automated manufacturers preoperative simulation systems: ArthrexVIP™ (AMPS I) and Tornier Blueprint™ 3D Planning (AMPS II). Preoperative plans were compared for reliability and consistency among different software systems based on available variables including humeral head diameter (HD) and head height (HH).

RESULTS

The measured HD was consistent between the three systems with a maximum mean difference of 0.2 mm for HD among IPPS, AMPS I, and AMPS II (p = 0.964). There was a significant difference in measured humeral HH with 1.7 mm difference between IPPS and AMPS II (p ≤ 0.001). The strongest correlation when comparing humeral head measurements (diameter or height) obtained from all systems was seen between IPPS and AMPS I for humeral HD (r = 0.8; p ≤ 0.001).

CONCLUSION

There was a high level of consistency between independent and manufacturer preoperative planning software for humeral head measurements. These preoperative planning systems can improve efficiency and workflow during surgery by guiding surgeons on implant size selection to optimally reconstruct the glenohumeral kinematics, in order to improve patient outcomes.

LEVEL OF EVIDENCE

Level III, study of nonconsecutive patients and without a universally applied "gold" standard study of diagnostic test.

Preoperative Patient-Reported Outcomes Measurement Information System (PROMIS) scores predict postoperative outcome in total shoulder arthroplasty patients

BACKGROUND

The Patient-Reported Outcomes Measurement Information System (PROMIS) has recently been validated in orthopedic patients with upper-extremity disease. The purpose of this study was to describe preoperative and postoperative PROMIS scores in total shoulder arthroplasty (TSA) patients, compare PROMIS physical function (PF) scores with clinical functional measurements, and determine whether preoperative PROMIS scores could predict achievement of the minimal clinically important difference (MCID) postoperatively.

METHODS

Preoperative and postoperative (>3 months) PROMIS scores in patients who underwent primary anatomic TSA were reviewed. Preoperative and postoperative shoulder forward flexion and external rotation were also collected. PROMIS PF, pain interference (PI), and depression scores were compared. Accuracy analyses determined whether preoperative PROMIS scores from each domain could predict postoperative achievement of the MCID in the same domain.

RESULTS

The study included 62 patients. Significant improvements in PROMIS PF, PI, and depression scores, as well as forward flexion and external rotation, were found postoperatively (P < .001). The multivariate model demonstrated that preoperative PROMIS PF, PI, and depression scores were predictive of postoperative achievement of the MCID (area under the receiver operating characteristic curve, 0.70-0.87). Ninety percent cutoff scores showed that patients with a preoperative PF score lower than 31.7, PI score greater than 66.9, and depression score greater than 55.5 were more likely to achieve the MCID.

CONCLUSIONS

In TSA patients, preoperative PROMIS PF, depression, and PI scores demonstrated strong to excellent abilities to predict postoperative achievement of the MCID. PROMIS PF scores were responsive to the functional improvements observed clinically. The reported cutoff scores allow surgeons to identify patients with increased or decreased probabilities of achieving a clinically meaningful improvement after TSA.