Factors associated with genetic markers for rotator cuff disease in patients with atraumatic rotator cuff tears

For atraumatic rotator cuff tears, genetics contributes to symptomatic tear risk and may influence rotator cuff healing after surgical repair. But little is known about how genetic factors influence rotator cuff tear patient characteristics at presentation. We collected saliva samples for genotyping from atraumatic rotator cuff tear patients. We examined nine single nucleotide polymorphisms (SNPs) associated with cuff tears in prior literature. We estimated associations of SNP dosage with (1) age at tear diagnosis, (2) bilateral atraumatic tear prevalence, and (3) tear size. Linear regression was used to estimate associations with diagnosis age adjusted for sex and principal components. Logistic regression and ordinal logistic regression were used to estimate associations with bilateral tear prevalence and tear size category, respectively, adjusting for age, sex, and principal components. Of 344 eligible patients, 336 provided sufficient samples for genotyping. Median age at tear diagnosis was 61, 22% (N = 74) had bilateral atraumatic tears, and 9% (N = 29) had massive tears. SNP rs13107325 in the SLC39A8 gene and rs11850957 in the STXBP6 gene were associated with younger diagnosis age even after accounting for multiple comparisons (rs13107325: -4 years, 95% CI = -6.5, -1.4; rs11850957: -2.7 years, 95% CI = -4.3, -1.1). No other significant associations were observed with diagnosis age, tear size, or bilateral tear prevalence. SLC39A8 encodes a Mn transporter. STXBP6 may play a role in inflammatory responses by altering phagocytosis and antigen presentation of monocytes and macrophages. Further research is needed to determine if genetic markers can be used alongside patient characteristics to aid in identifying optimal surgical repair candidates.

Revision of failed reverse total shoulder arthroplasty with reverse: short-term clinical outcomes

BACKGROUND

The prevalence of failed reverse total shoulder arthroplasty (rTSA) is increasing. This can often present a challenging clinical situation with substantial bone loss and limited reconstruction options. This study reports a single tertiary referral center's experience with revision of failed rTSA managed with revision rTSA of bone-interfacing components.

METHODS

After institutional review board approval, all revision shoulder arthroplasty cases performed at a single institution between 2012 and 2020 were reviewed. Cases in which rTSA was revised to a new rTSA construct with revision of at least 1 bone-interfacing implant (humeral stem and/or baseplate) with a minimum 2-year follow-up were identified. Characteristics of revision cases-including indications, bony stock, revised components, and use of bone graft-were collected. All patients were contacted for patient-reported outcome measures at a minimum of 2 years after surgery. In addition, the incidence and indication for any reoperation after revision were determined.

RESULTS

Thirty-three patients with an average age of 66 years (range: 46-82 years), with 19 (58%) being female, met the inclusion criteria and had a mean follow-up of 4.2 years (range: 2-8 years). The most common indication for revision rTSA included humeral component loosening (33%; 11/33), baseplate loosening (27%; 9/33), and instability (21%; 7/33). Prerevision infectious workup demonstrated no cases of periprosthetic shoulder infection. Thirteen cases had massive bone loss-5 treated with humeral allograft prosthetic composite, 5 with glenoid bone grafting, and 3 with custom glenoid implant. In total, 10 of 33 cases (30%) required reoperation at a mean of 13 months (range: 1-44 months) for instability (4), humeral loosening (2), infection (1), baseplate loosening (1), or periprosthetic fracture (1). The reoperation rate for patients with revised baseplates only, humerus only, or combined was 23% (3/13), 28% (5/18), and 27% (3/11), respectively. Overall, the visual analog scale pain score improved from 6.5 preoperatively to 2.0 (P < .001), and the American Shoulder and Elbow Surgeons score improved from 30.7 to 67.5 (P < .001). However, the postoperative Single Assessment Numeric Evaluation score averaged only 51.2% (range: 2-100%).

CONCLUSION

This study demonstrates that failed rTSA can be salvaged with a revision rTSA. However, patient expectations for functional improvements should be tempered, and a high reoperation rate should be expected.

Three-dimensional analysis of biplanar glenoid deformities: what are they and can they be virtually reconstructed with anatomic total shoulder arthroplasty implants?

BACKGROUND

Descriptions of glenoid deformities in glenohumeral osteoarthritis (GHOA) have focused on the axial plane. Less is known regarding arthritic glenoids with higher amounts of superior inclination and little evidence exists to guide management of inclination or combined version-inclination deformity when performing anatomic total shoulder arthroplasty (aTSA). We hypothesized that biplanar deformities (BD) would be present in a higher proportion of GHOA patients than previously appreciated, and these deformities would be difficult to adequately reconstruct with contemporary aTSA implants.

METHODS

A retrospective query was performed of GHOA patients indicated for TSA 2012-2017 with a computed tomography (CT) scan within three months of surgery. Images were uploaded to three-dimensional (3D) software for automated measurements. Glenoids with superior inclination ≥10°, and retroversion ≥20° were considered to have BD. Walch classification was determined, and C-type glenoids were excluded. Rotator-cuff muscle cross-sectional area (CSA) was measured and fatty infiltration was graded. Glenoids with BD were virtually planned for aTSA with correction to neutral inclination and version, then with 5° superior inclination and 10° retroversion.

RESULTS

Two-hundred and sixty-eight shoulders in 250 patients were included; average age was 65 years, 67% male. There were no differences in inclination between Walch types (P = .25). Twenty-nine shoulders with BD were identified (11%). These deformities were not associated with age (P = .47) or gender (P = .50) but were skewed towards Walch B-type, specifically B2 (P = .03). Acromial index and posterior humeral head subluxation were higher in BD patients (P = .04, P < .001, respectively). Biplanar deformities had similar cuff CSA compared to those without but were less frequently associated with fatty infiltration of the subscapularis (P = .05). When correcting to neutral version and inclination, 41% BD could not be reconstructed. Of those that could, 94% required augmented implants. When correcting to 5° superior inclination and 10° retroversion, 10% could not be reconstructed. Of those that could, 58% required augmented implants. With partial correction, augment use was predicted by retroversion >26° (P = .009). Inclination did not predict augment use (P = .90). Final implant position commonly involved unseating in the posterosuperior quadrant and cancellous exposure in the anteroinferior quadrant.

CONCLUSIONS

This retrospective computed tomography (CT)-based study of 268 shoulders with GHOA found an 11% prevalence of BD. These deformities were commonly associated with Walch B2 wear patterns. Virtual aTSA planning showed a high failure rate (41%) when correcting to neutral version and inclination. Posteriorly augmented implants were frequently required, and often still involved unseating in the posterosuperior quadrant, increased cancellous exposure in the anteroinferior quadrant, and vault perforation.

Predictors of pain development for contralateral asymptomatic degenerative rotator cuff tears based on features of an ipsilateral painful cuff tear: a prospective longitudinal cohort study

BACKGROUND

Prior rotator cuff disease natural history studies have focused on tear-related factors that predict disease progression within a given shoulder. The purpose of this study was to examine both patient- and tear-related characteristics of a painful rotator cuff tear that predict future pain development and functional impairment in a shoulder with a contralateral asymptomatic cuff tear.

METHODS

This was a prospective longitudinal cohort study of patients aged ≤65 years who underwent surgery for a painful degenerative rotator cuff tear and possessed an asymptomatic contralateral tear. Patients were followed up prospectively by shoulder ultrasound, physical examination, and functional score assessment. The primary outcome was change in the American Shoulder and Elbow Surgeons (ASES) score at 2 years. Secondary outcomes included the Western Ontario Rotator Cuff Index (WORC) score, Patient-Reported Outcomes Measurement Information System (PROMIS) score, Hospital Anxiety Depression Scale (HADS) depression and anxiety scores, and Veterans RAND-12 (VR-12) mental component score (MCS).

RESULTS

Sixty-five patients were included, with a mean follow-up period of 37 months (range, 24-42 months). In 17 patients (26%), contralateral shoulder pain developed at a median of 15.2 months (interquartile range [IQR], 10.5 months). No difference in age, sex, Charlson Comorbidity Index, or occupational demand was noted between patients in whom pain developed and those in whom pain did not develop. In the presenting painful shoulder, there was no difference in baseline tear size, muscle degeneration, or biceps pathology between groups. The mean baseline tear length (8.6 mm vs. 3.8 mm, P = .0008) and width (8.4 mm vs. 3.2 mm, P = .0004) were larger in asymptomatic shoulders in which pain subsequently developed compared with those in which pain did not develop. However, there was no difference in mean tear enlargement (P = .51 for length and P = .90 for width). There were no differences in baseline ASES, WORC, Patient-Reported Outcomes Measurement Information System (PROMIS), or HADS depression and anxiety scores between shoulders in which pain developed and those in which pain did not develop; however, patients in whom pain developed reported a lower baseline VR-12 MCS (53.3 vs. 57.6, P = .04). Shoulders in which pain developed had higher visual analog scale pain scores (2.9 [standard deviation (SD), 2.5] vs. 0.6 [SD, 1.0]; P = .016), lower ASES scores 75 [SD, 33] vs. 100 [SD, 11.6]; P = .001), and significant changes in all WORC scales with pain onset compared with those that remained asymptomatic. The study showed no significant difference in changes in the HADS anxiety and depression scores but found a significant increase in the VR-12 MCS in patients in whom pain developed (7.1 [interquartile range, 12.6] vs. -1.9 [interquartile range, 8.7]; P = .036).

CONCLUSION

In one-quarter of patients with painful cuff tears, pain developed in a contralateral asymptomatic cuff tear that resulted in a measurable decline in function within 3 years. Our analysis showed that only the baseline tear size of the asymptomatic shoulder was predictive of pain development. There were no tear-related features of the presenting painful rotator cuff tear or indices of mental health and physical function or occupational demand that were predictive of future pain development at short-term follow-up.

Evaluation of Survivorship of Asymptomatic Degenerative Rotator Cuff Tears in Patients 65 Years and Younger: A Prospective Analysis with Long-Term Follow Up

BACKGROUND

The purpose of this prospective study is to describe the mid to long-term natural history of untreated asymptomatic degenerative rotator cuff tears in patients 65 years and younger.

METHODS

Subjects with an asymptomatic rotator cuff tear in one shoulder and a contralateral painful cuff tear age 65 years or younger were enrolled in a previously described prospective longitudinal study. Annual physical and ultrasonographic evaluations and surveillance for pain development were performed utilizing independent examiners for the asymptomatic shoulder.

RESULTS

Two hundred twenty-nine subjects (mean age 57.1 years) were followed for a median of 7.1 (range 0.3-13.1) years. Tear enlargement occurred in 138 (60%) shoulders. Full-thickness tears were at greater risk for enlargement compared to partial-thickness (HR=2.93, 95%CI 1.71-5.03, p<0.0001) and control shoulders (HR=18.8, 95%CI 4.63-76.1, p<0.0001). Mean survival rates from Kaplan-Meier analyses indicate that full-thickness tears enlarged earlier (mean 4.7, 95%CI 4.1-5.2 years) than partial-thickness (mean 7.4, 95%CI 6.2-8.5 years) and control shoulders (mean 9.7, 95%CI 9.0-10.4 years). Tear presence in the dominant shoulder was associated with a greater enlargement risk (HR=1.70, 95%CI 1.21-1.39, p=0.002). Patient age (p=0.37) and gender (p=0.74) were not associated with tear enlargement. The 2,5 and 8-year survivorship free of tear enlargement for full-thickness tears was 74%, 42% and 20%, respectively. Shoulder pain developed in 131 (57%) shoulders. Pain development was associated with tear enlargement (HR=1.79, 95%CI 1.24-2.58, p=0.002) and was more common in full-thickness tears compared to controls (p=0.0003) and partial tears (p=0.01). An analysis of progression of muscle degeneration was performed 138 shoulders with full-thickness tears. Tear enlargement was seen in 104 of 138 (75%) of these shoulders during follow-up (median 7.7 [6.0] years). Progression of muscle fatty degeneration was seen in the supraspinatus in 46 (33%) and the infraspinatus in 40 (29%) shoulders. Adjusting for age, both the presence of fatty muscle degeneration and the progression of muscle changes for both the supraspinatus (p<0.0001) and infraspinatus (p<0.0001) muscles were associated with tear size. For both the supraspinatus (p=0.03) and infraspinatus (p=0.03) muscles, tear enlargement was significantly associated with progression of muscle fatty degeneration. Anterior cable integrity was significantly associated with the risk of muscle degeneration progression for both the supraspinatus (p<0.0001) and the infraspinatus (p=0.005) muscles.

CONCLUSIONS

Asymptomatic degenerative rotator cuff tears progress in patient 65 years and younger. Full-thickness rotator cuff tears have a higher risk of continued tear enlargement, progression of fatty muscle degeneration and pain development than partial-thickness tears.

Active physical therapy does not improve outcomes after reverse total shoulder arthroplasty: a multi-center, randomized clinical trial

OBJECTIVE

To compare range of motion (ROM) and patient-reported outcomes (PROs) between a structured home exercise program (HEP) and active, supervised physiotherapy (PT) after primary Reverse total shoulder arthroplasty (RTSA) by performing a multicenter randomized clinical trial.

METHODS

Patients undergoing primary RTSA at 2 centers were randomized to either a HEP group, in which they were given a handout and a rope pulley, or a PT group, in which they were given a standardized prescription. Surgical technique and implants were standardized. At baseline, 6 weeks, 3 months, and 1 year postoperatively, we obtained American Shoulder and Elbow Surgeons scores, Western Ontario Osteoarthritis Scores, visual analogue scale for pain scores, and measured ROM via videotape. On video, ROM was then measured by blinded observers. At all study visits, patients were asked how many days per week they were in PT and how many days a week they completed HEP to determine compliance and crossover. An a priori power analysis suggested 29 patients per group, 56 patients total to detect a difference of 30° in active forward elevation with a power of 0.8 at a 2-sided alpha of 0.05.

RESULTS

89 patients were randomized, 43 to PT, and 46 to HEP. We obtained 1-year PRO follow-up on 83 patients (93%) and ROM follow-up on 73 patients (82%). Nine patients (20%) crossed over from HEP to PT and 2 patients (4%) crossed over from PT to HEP. Complications occurred in 13% of HEP and 17% of PT patients (P = .629). Using mixed models that account for baseline values, there were no significant differences between groups in PROs or ROM at final follow-up.

CONCLUSION

In this 2-center, randomized clinical trial, there were no significant differences in patient outcomes or ROM between HEP and PT after RTSA. These findings suggest that it may not be necessary to recommend PT as a protocol for all patients after RTSA.

Clinical outcomes after reverse shoulder arthroplasty in patients 60 years old and younger; medium-term results

Background

Reverse total shoulder arthroplasty (RTSA) has been well-described as a surgical solution to manage rotator cuff tear arthropathy in elderly, low demand paitents. As experience has increased along with improvements in technique and implant design, RTSA has become increasingly used to manage more varied pathologic conditions of the shoulder in younger, more active patients. This study evaluates outcomes in a consecutive series of patients aged 60 years old and younger after undergoing RTSA.

Methods

There were 94 shoulders in 89 patients enrolled. Mean age of the cohort was 54.8 (range 18-60 years). Surgical indications included rotator cuff tear arthropathy, irreparable rotator cuff tear without arthritis, glenohumeral arthritis with erosive glenoid deformity, inflammatory arthropathy, proximal humerus fracture nonunion/malunion and failed prior shoulder arthroplasty. Sixty-one shoulders (70%) had undergone at least one prior surgery. Of these, 6 shoulders (6% of total cohort) had a prior failed arthroplasty. Clinical outcomes (American Shoulder and Elbow Surgeons score, Western Ontario Osteoarthritis of the Shoulder index; visual analog scale pain), radiographic outcomes and complications were analyzed and assessed for correlation with patient demographic factors.

Results

The mean follow-up for this cohort was 4.9 years (range 2-12 years). Subjects experienced improvements in ASES score and pain (P < .001) and active forward elevation (88° preop to 135° postop, P < .001). Prior operation correlated with worse postoperative ASES and WOOS scores. Higher demand occupation correlated with less improvement in pain scores. The overall complication rate was 12%. Seven shoulders (7%) underwent an additional procedure. There was a 2% incidence of dislocation and a 4% incidence of acromial stress fracture. There was a 36% incidence of notching.

Conclusion

With medium-term follow-up, RTSA is a reliable and predictable operation to manage various pathologic conditions in patients aged 60 years or less. Patients predictably experience significant improvements in pain and range of motion while assuming a modest complication risk. Long-term study is needed to understand potential for late complications or implant failure.

Anatomic Shoulder Arthroplasty in Walch C Glenoid Deformity: Mid-to-Long Term Outcomes

BACKGROUND

Hypoplastic glenoid morphology in the setting of glenohumeral osteoarthritis is a rare, yet complex surgical problem. Treatment of this patient population with an anatomic total shoulder arthroplasty (aTSA) remains controversial. Furthermore, there is no gold standard approach with limited guidance for surgeons on the need for glenoid version correction in the setting of a dysplastic glenoid. The purpose of this study was to evaluate mid-to-long term outcomes and reoperation rates of aTSA for treatment of primary glenohumeral osteoarthritis with Walch C glenoid deformity.

METHODS

This observational, retrospective cohort study reviewed patients with a Walch C glenoid undergoing aTSA at two institutions between 2007 and 2016. Patients were contacted to complete updated patient-reported outcome measures at a minimum of 5.5 years postoperatively. Outcome measures collected included the American Shoulder and Elbow Surgeons (ASES) score and Single Alpha Numeric Evaluation (SANE) score. Secondary outcomes included any additional surgery on the operative shoulder, patient satisfaction, and willingness to undergo aTSA again.

RESULTS

Thirty patients met inclusion criteria, and 26 (86.7%) were able to be contacted for final outcomes evaluation. Mean age at time of surgery was 61.3 (range, 40.9 to 75.5) and 20 patients (76.9%) were male. Mean follow-up was 8.5 years (range 5.5 to 11.3) after surgery. Nine patients were treated with an augmented component and 17 with a standard component. Of the 17 non-augmented components, 9 were partially corrected with asymmetric reaming, 3 cases utilized a mini inset glenoid, and 2 cases anteriorly offset the humeral component. At final follow-up, patients had a mean ASES score of 83.6 +/- 16.7, ASES pain score of 24.7 +/- 20.8, SANE score of 80.4 +/- 20.9, and percent patient satisfaction of 84.1%. There were no statistically significant differences in any outcome measure between those with augmented and non-augmented glenoid components. There was one revision to reverse for instability at 7 years postoperatively after a traumatic dislocation. All patients reported that they would want to undergo the same surgery again.

DISCUSSION

Despite variance in glenoid reconstructive approach, aTSA provides satisfactory and sustained improvements in patient-reported outcomes in patients with glenoid dysplasia and primary glenohumeral osteoarthritis with a low revision rate at mean 8.5 years. Anatomic shoulder arthroplasty should remain a surgical option in patients with Walch C glenoid deformity.

Rehabilitation after Shoulder Instability Surgery

Shoulder instability can occur in any direction and presents across a broad spectrum including traumatic dislocations, repetitive microinstability events or subluxations, and global joint laxity. The development of pain, functional decline, and articular pathologic condition is a multifaceted process that is influenced by the underlying bony morphology, biology of the surrounding soft tissue structures, dynamic coordination of the periscapular musculature, and patient factors such as age, activity level, and associated injuries. This article will focus on the younger, active patient with instability due to deficiencies in the capsulolabral complex and dynamic stabilizers.

Total Shoulder Arthroplasty in Patients with a B2 Glenoid Addressed with Corrective Reaming: Mean 8-year Follow-up

BACKGROUND

The management of Walch B2 glenoid deformities in primary glenohumeral osteoarthritis is frequently debated. Previous literature has shown that the treatment of B2 glenoids with high-side reaming and anatomic total shoulder arthroplasty (TSA) perform well in the short-term, but is associated with an increased glenoid component failure rate in severe deformities. Therefore, many have explored alternative options, including augmented anatomic glenoid components and reverse shoulder arthroplasty. Our goal in this study is to provide mid-term radiographic and clinical outcomes after high-side reaming and anatomic TSA for B2 glenoids.

METHODS

Patients were followed both clinically and radiographically. Preoperative CT scans were used for retrospective analysis of deformity. Both preoperative and postoperative VAS pain, ASES score, and SST scores were collected. Radiographs were analyzed preoperatively and postoperatively for humeral head decentering relative to the glenoid vault, immediate glenoid seating, and final glenoid peg radiolucency.

RESULTS

Of the original cohort of 59 patients (6 now deceased) reported at a mean radiographic follow-up of 3.4 years, 34 shoulders in 33 patients with B2 glenoids (mean retroversion 18.9°, range 4°-32°) were available for follow-up at a mean of 8.6 years (range 5.5-11.2) after high-side glenoid reaming with anatomic TSA. Three (5.1%) of the original 59 shoulder were revised. At final follow-up, 3 of 30 (10.0%) shoulders had radiographic glenoid component failure, but were unrevised. Glenoid component failure was associated with worse initial glenoid component seating (mean Lazarus score 1.2 vs. 2.0, p=0.002). Glenoid failure was also associated with increased posterior humeral head subluxation at 2-4 year follow-up (mean 5.6% vs 12.6%, p=0.045) and at final follow-up (mean 7.0% vs. 21%, p=0.002). There was no association between glenoid component failure and preoperative retroversion, inclination, or humeral head subluxation (all p>0.05). Glenoid component failure was associated with worse ASES (88 vs. 73) and VAS pain (0.8 vs. 2.1) scores (both p=0.03).

CONCLUSIONS

At a mean of 8.6 years, 88% of shoulders available for follow-up had well-fixed glenoid components. Glenoid component failure was associated with poor initial glenoid component seating, with failed components having an average of 25% of the glenoid component not seated. Preoperative deformity such as glenoid retroversion, inclination, or humeral head subluxation did not predict glenoid component failure. This study supports that initial glenoid component seating and recurrence of posterior humeral head subluxation may be the most important factors for mid-term glenoid component survival in anatomic TSA in patients with B2 glenoids.

Diagnosis and Management of Early Complications After Reverse Shoulder Arthroplasty

Reverse shoulder arthroplasty has become the predominant shoulder arthroplasty procedure. Despite newer design modifications, complications still occur after reverse shoulder arthroplasty. Early complications include instability, acromial and scapular spine stress fractures, periprosthetic fractures, periprosthetic joint infections, and neurologic injury. It is important to discuss the diagnosis and management of these early complications.

My Reverse Has Failed: Top Five Complications and How to Manage Them

Reverse total shoulder arthroplasty implantation has increased dramatically over the past 4 decades since it was first introduced in France in 1985. It has greatly improved the ability to treat patients with cuff tear arthropathy, proximal humeral fractures, and osteoarthritis with severe bone loss. However, with the increased implementation of reverse total shoulder arthroplasty, there has been a corresponding rise in complications. Five of the most common complications following reverse total shoulder arthroplasty are instability, scapular fractures, periprosthetic humeral fractures, glenoid baseplate loosening, and infection.

Occupational demands associated with rotator cuff disease surgery in the UK Biobank

OBJECTIVES

Physically-demanding occupations may increase rotator cuff disease (RCD) risk and need for surgery. We linked a job-exposure matrix (JEM) to the UK Biobank cohort study to measure physical occupational exposures and estimate associations with RCD surgery.

METHODS

Jobs and UK Standard Occupational Classification (SOC) codes were recorded during the UK Biobank verbal interview. Lifetime job histories were captured through a web-based survey. UK SOC codes were linked to a JEM based on the US O*NET database. O*NET-based scores [static strength, dynamic strength, general physical activities, handling/moving objects (range=1-7), time spent using hands, whole body vibration, and cramped/awkward positions (range=1-5)] were assigned to jobs. RCD surgeries were identified through linked national hospital inpatient records. Multivariable Cox regression was used to calculate hazard ratios (HR) as estimates of associations with RCD surgery. Among those with lifetime job histories, associations were estimated for duration of time with greatest exposure (top quartile of exposure).

RESULTS

Of 277 808 people reporting jobs, 1997 (0.7%) had an inpatient RCD surgery. After adjusting for age, sex, race, education, area deprivation, and body mass index, all O*NET variables considered were associated with RCD surgery (HR per point increase range=1.10-1.45, all P<0.005). A total of 100 929 people reported lifetime job histories, in which greater exposures were significantly associated with RCD surgery after >10 years of work (eg, HR for 11-20 versus 0 years with static strength score ≥4 = 2.06, 95% confidence interval 1.39-3.04).

CONCLUSIONS

Workplace physical demands are an important risk factor for RCD surgery, particularly for workers with more than a decade of exposure.

Predictors of Internal Rotation after Reverse Shoulder Arthroplasty

Objectives

Internal rotation (IR) remains unpredictable following reverse total shoulder arthroplasty (rTSA). This study aimed to determine if increasing IR limits range of motion in other planes, and to determine pre- and intra-operative factors associated with post-operative IR.

Methods

A retrospective analysis of a single surgeon's primary rTSA with a single implant was undertaken, excluding patients with acute fracture or infection. A lesser tuberosity osteotomy (LTO) or subscapularis peel tenotomy was performed and repaired at the surgeon's discretion. One hundred sixty rTSA were included; 142 (88.8%) had documented IR both pre-operatively and at one-year follow-up. Variables were collected to determine their effect on IR at the 1-year follow-up point. A multivariate logistic regression was used to determine independent predictors of sufficient IR.

Results

Average age was 69.8 (range: 55-86) years and 55% (88/160) were female. Preoperatively, 20.4% of patients (29/142) had sufficient IR. This improved to 32.4% (46/142) one year following surgery, p<0.001). Factors associated with sufficient post-operative IR were female sex (p=0.05), decreasing body mass index (p=0.04), pre-operative IR (p=0.01), preoperative external rotation (ER) in adduction (p<0.001), radiographic evidence of LTO healing (p=0.02), increased one-year postoperative forward elevation (p<0.001), and increased one-year postoperative ER (p<0.001). Increased postoperative IR did not adversely affect forward elevation or ER. On multivariate analysis, higher preoperative IR and one-year postoperative forward elevation were independently associated with sufficient one-year postoperative IR.

Conclusion

IR following rTSA continues to be modest and unpredictable. Independent predictors of sufficient post-operative internal rotation were higher preoperative IR and one-year postoperative forward elevation. In a Grammont-style rTSA system, humeral version, glenosphere lateralization, and glenosphere size do not appear to impact IR. Importantly, achieving sufficient IR does not come at the expense of other planes of motion.

The rate and predictors of healing of repaired lesser tuberosity osteotomy in reverse total shoulder arthroplasty

Background

Evidence is building that a functional subscapularis improves function-specifically internal rotation tasks-following reverse total shoulder arthroplasty (rTSA). However, the optimal method for subscapularis repair during rTSA remains unknown with variable healing rates reported. This study aims to investigate the rate of and predictors for healing a lesser tuberosity osteotomy (LTO) following rTSA.

Methods

Following local institutional review board approval, patients with at least one-year follow-up for rTSA managed with an LTO and subsequent repair between March, 2017 and March, 2020 were retrospectively identified. Shoulders were selected for LTO repair based upon preoperative imaging and intraoperative assessment of subscapularis quality. All patients were implanted with a system consisting of a 150° or 155° (constrained) humeral neck-shaft angle and 2.5 to 4.5 millimeters (mm) of glenoid lateralization (Trabecular Metal Reverse Shoulder System; Zimmer Biomet, Warsaw, IN, USA). At a minimum of six months, radiographs were reviewed for an assessment of LTO healing by three independent reviewers. Healing was classified as displaced, fibrous union, or ossified union. For assessing predictors, the repair was considered intact if the LTO fragment was not displaced (fibrous union or ossified union).

Results

Sixty-five rTSA with LTO repair were performed in 64 patients. These patients had an average age of 67.2 years (range, 31-81) and 36 (55.4%; 36/65) were female. At an average follow-up of 15.2 months (range, 8-38), 50 cases (76.9%; 50/65) were classified as having an ossified union. The radiographic healing could not be assessed in a single case. Of the 14 cases without ossific union, 8 (12.3%; 8/65) were displaced and 6 (9.2%; 6/65) were classified as a fibrous union. In logistic regression, only combined humeral liner height predicted LTO displacement (odds ratio = 1.4 [95% confidence interval = 1.1-1.8]; P = .01). Humeral loosening was not found in any cases following LTO.

Conclusion

This analysis demonstrates that radiographic healing of LTO repair is more favorable than published rates of healing after subscapularis tenotomy or peel in the setting of rTSA. Subscapularis management with LTO provides the ability to monitor repair integrity with plain radiographs and a predictable radiographic healing rate. The integrity of subscapularis repair may be influenced by the use of thicker humeral liners. Further investigation is needed to determine the functional impact of a healed subscapularis following rTSA.

Symptomatic aseptic loosening of a short humeral stem following anatomic total shoulder arthroplasty

INTRODUCTION

The rate of aseptic humeral component loosening with standard-length stems is historically so low (0.3%) that presence of humeral loosening was given substantial weight in defining periprosthetic shoulder infection by the International Consensus Meeting (ICM) in 2018. This study aims to confirm that the historically low rate of humeral stem aseptic loosening is not affected by the adoption of a novel short humeral stem.

METHODS

Following institutional review board approval, this retrospective multi-institutional study was undertaken. A review of anatomic total shoulder arthroplasty (TSA) cases at 3 institutions provided 184 shoulders that received TSA with a grit-blasted, rectangular short humeral stem without ingrowth coating (Univers Apex; Arthrex). The average patient age was 62.1 years (range: 30-84), and 57.1% (105/184) were male. One-year radiographic follow-up was achieved in 64.7%. Patient clinical charts were reviewed for onset of newly painful shoulders, radiographic evidence of loosening, and return to the operating room for any reason. All patients with concern for clinically significant humeral loosening underwent workup for periprosthetic shoulder infection. Immediate postoperative films were reviewed to identify any differences in prosthetic canal fit. The definition of periprosthetic shoulder infection used was provided by the recent ICM shoulder guidelines.

RESULTS

Twenty-three (12.5%) patients presented with a painful shoulder and radiographic concern for potential humeral loosening at a mean follow-up of 1.5 years (range: 1.5 months-3.4 years). Thirteen (7.1%) of these underwent revision shoulder arthroplasty where a loose stem was confirmed. All revisions underwent tissue culture, and 3 cases were consistent with probable or possible periprosthetic infection at the time of revision arthroplasty. The rate of symptomatic aseptic humeral loosening in this series was 10.9% (20/184), with 5.4% undergoing revision surgery. Patients with symptomatic aseptic humeral loosening were more likely to be male (90.5%) than those patients without symptoms (52.8%, P < .001). There were no differences in canal fit between patients with concern for symptomatic loosening and those with pain-free, stable implants.

CONCLUSION

In this multisurgeon, multicenter study, the early humeral loosening rate for this stem design far outpaces previously reported rates, and this study likely under-reports the true incidence of clinically significant loosening as it only contains limited short-term follow-up. The perception that humeral loosening is nearly pathognomonic for periprosthetic shoulder infection should be reconsidered for certain short humeral stem designs.

Trends in rotator cuff repair rates and comorbidity burden among commercially insured patients younger than the age of 65 years, United States 2007-2016

Background

Prior US studies have shown increasing rotator cuff repair rates through 2009. We hypothesize that rotator cuff repair rates are continuing to increase and the comorbidity profiles of patients are becoming more complex over time.

Methods

We identified rotator cuff repairs in a large US cohort of people 18-64 years of age with ≥1 year of commercial insurance coverage. Repair rate trends across time were standardized by age, sex, and geographic region. Procedures were categorized as inpatient vs. outpatient and as arthroscopic vs. open. Prevalent comorbidities were defined as 1 inpatient diagnosis claim or 2 outpatient diagnosis claims during the year before rotator cuff repair. General population comorbidity prevalence was determined based on a random 5% sample of the commercially insured population and compared with patients with rotator cuff repair using standardized morbidity ratios.

Results

From 2007 to 2016, 314,239 rotator cuff repairs were identified (165 repairs per 100,000 person-years). Rotator cuff repairs were performed more frequently in men, older people, and in the Midwest. Across time, cuff repair rates increased by 1.6% per year (95% confidence interval [CI] = +1.4%-1.7%) adjusting for demographics. The highest increases in repair rates were observed among patients aged 50-64 years (+2.0%, 95% CI = +1.8%-2.2%). Rotator cuff repairs were more frequently performed using an arthroscopic approach and in an outpatient setting in later calendar years. In 2016, 83% of rotator cuff repairs were arthroscopic procedures and 99% were performed as outpatient procedures. Comorbidity prevalence in rotator cuff repair patients increased across calendar time by 4.5% per year for hypertension (95% CI = +4.2%-4.7%), 2.3% per year for diabetes (+1.9%-2.7%), 0.9% per year for hypercholesterolemia (+0.3%-1.5%), 2.9% for congestive heart failure (+0.8%-4.9%), 4.2% for peripheral vascular disease (+2.4%-6.0%), and 4.2% for chronic pulmonary disease (+3.6%-4.8%). Comorbidity prevalence in repair patients was higher than prevalence in the general population, and prevalence relative to the general population was most heightened during later calendar years. For example, hypertension prevalence was 1.58 times higher in repair patients than the general population in 2007 (95% CI = 1.53-1.62), and 2.06 times higher in 2016 (95% CI = 2.02-2.11).

Conclusion

Rotator cuff repair is becoming more frequent in the US commercially insured population, particularly in those 50-64 years of age. More rotator cuff repairs are being performed using an arthroscopic approach and in an outpatient setting. Over time, the comorbidity profile of patients undergoing rotator cuff repair is becoming more complex with greater prevalence of numerous conditions, including hypertension, peripheral vascular disease, and chronic pulmonary disease.

Identification of a Novel Genetic Marker for Risk of Degenerative Rotator Cuff Disease Surgery in the UK Biobank

BACKGROUND

While evidence indicates that familial predisposition influences the risk of developing degenerative rotator cuff disease (RCD), knowledge of specific genetic markers is limited. We conducted a genome-wide association study of RCD surgery using the UK Biobank, a prospective cohort of 500,000 people (40 to 69 years of age at enrollment) with genotype data.

METHODS

Cases with surgery for degenerative RCD were identified using linked hospital records. The cases were defined as an International Classification of Diseases, Tenth Revision (ICD-10) code of M75.1 determined by a trauma/orthopaedic specialist and surgery consistent with RCD treatment. Cases were excluded if a diagnosis of traumatic injury had been made during the same hospital visit. For each case, up to 5 controls matched by age, sex, and follow-up time were chosen from the UK Biobank. Analyses were limited to European-ancestry individuals who were not third-degree or closer relations. We used logistic regression to test for genetic association of 674,405 typed and >10 million imputed markers, after adjusting for age, sex, population principal components, and follow-up.

RESULTS

We identified 2,917 RCD surgery cases and 14,158 matched controls. We observed 1 genome-wide significant signal (p < 5 × 10-8) for a novel locus tagged by rs2237352 in the CREB5 gene on chromosome 7 (odds ratio [OR] = 1.17, 95% confidence interval [CI] = 1.11 to 1.24). The single-nucleotide polymorphism (SNP) rs2237352 was imputed with a high degree of confidence (info score = 0.9847) and is common, with a minor allele frequency of 47%. After expanding the control sample to include additional unmatched non-cases, rs2237352 and another SNP in the CREB5 gene, rs12700903, were genome-wide significant. We did not detect genome-wide significant signals at loci associated with RCD in previous studies.

CONCLUSIONS

We identified a novel association between a variant in the CREB5 gene and RCD surgery. Validation of this finding in studies with imaging data to confirm diagnoses will be an important next step.

CLINICAL RELEVANCE

Identification of genetic RCD susceptibility markers can guide understanding of biological processes in rotator cuff degeneration and help inform disease risk in the clinical setting.

LEVEL OF EVIDENCE

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

The relationship between glenoid inclination and instability following primary reverse shoulder arthroplasty

PURPOSE

Despite advances in implant design and surgical technique, instability remains the most common early complication and reason for early revision after reverse shoulder arthroplasty (RSA). The purpose of this study is to evaluate the glenoid implant inclination, as measured by the β-angle, as an independent risk factor for instability after primary RSA.

METHODS

A retrospective case-control study was conducted matching cases with instability after primary RSA using a single implant to controls without instability. Controls were matched to age, sex, body mass index, and baseplate type (1:3 ratio of cases to controls). The preoperative, postoperative, and the change in pre- to postoperative glenoid inclination (β-angle) were compared between groups.

RESULTS

Thirty-four cases (mean age, 66.2 years) were matched to 102 controls (mean age, 67.0 years). There was a wide range of postoperative (63° to 100°) and pre- to postoperative change (-16.5° to +30.5°) in β-angles collectively. There was no significant difference in the postoperative β-angle (mean, 80.8° vs. 82.7°, P = .19) or the change in β-angle (mean, +1.7° vs. +3.4°, P = .35) between cases and controls, respectively. Regression analysis demonstrated no increased odds of instability with the postoperative β-angle, odds ratio 0.965 (confidence interval [CI] = 0.916-1.02, P = .19). Likewise, for the preoperative to postoperative change in β-angle, there was no significantly increased odds of instability, odds ratio 0.978 (CI = 0.934-1.03, P = .35). Finally, there was no difference in risk of instability in patients whose implant positioning resulted in a net superior increase in inclination, relative risk 0.85 (95% CI = 0.46-1.56, P = .28).

CONCLUSIONS

Neither the final prosthetic glenoid inclination nor the change in glenoid inclination, as measured by the β-angle, significantly influences the risk of prosthetic instability after primary RSA.

Infraspinatus and deltoid length and patient height: implications for lateralization and distalization in reverse total shoulder arthroplasty

BACKGROUND

Restoration of muscular strength is predicated on restoration of muscle length. The purpose of this study was to describe infraspinatus and deltoid length preoperative to reverse total shoulder arthroplasty (RTSA) to guide distalization and lateralization to restore preoperative muscle length.

METHODS

This was a retrospective radiographic study. We measured the infraspinatus length on preoperative computed tomographic images and the deltoid length on preoperative radiographs. For all measurements, reliability was first established by comparing measurements between 2 observers, and intraclass correlation coefficients (ICCs) were calculated. We then calculated descriptive statistics for these muscle lengths and developed a formula to predict these muscle lengths from patient demographics.

RESULTS

We measured infraspinatus length in 97 patients and deltoid length in 108 patients. Inter-rater reliability was excellent, with all ICCs >0.886. The mean infraspinatus length was 15.5 cm (standard deviation 1.3) and ranged from 12.6-18.9 cm, whereas the deltoid length was 16.2±1.7 cm and ranged from 12.5-20.2 cm. Both infraspinatus (r = 0.775, P < .001) and deltoid length (r = 0.717, P < .001) were highly correlated with patient height but did not differ between diagnoses. Formulae developed through linear regression allowed prediction of muscle length to within 1 cm in 78% and within 2 cm in 100% for the infraspinatus and 60% and 88% for the deltoid.

CONCLUSION

Deltoid and infraspinatus length are variable but highly correlated with patient height. To maintain tension, 2 mm of lateralization and distalization should be added for every 6 inches (∼15 cm) of height above average for a Grammont-style RTSA.

Reliability of the modified Walch classification for advanced glenohumeral osteoarthritis using 3-dimensional computed tomography analysis: a study of the ASES B2 Glenoid Multicenter Research Group

BACKGROUND

Variations in glenoid morphology affect surgical treatment and outcome of advanced glenohumeral osteoarthritis (OA). The purpose of this study was to assess the inter- and intraobserver reliability of the modified Walch classification using 3-dimensional (3D) computed tomography (CT) imaging in a multicenter research group.

METHODS

Deidentified preoperative CTs of patients with primary glenohumeral OA undergoing anatomic or reverse total shoulder arthroplasty (TSA) were reviewed with 3D imaging software by 23 experienced shoulder surgeons across 19 institutions. CTs were separated into 2 groups for review: group 1 (96 cases involving all modified Walch classification categories evaluated by 12 readers) and group 2 (98 cases involving posterior glenoid deformity categories [B2, B3, C1, C2] evaluated by 11 readers other than the first 12). Each case group was reviewed by the same set of readers 4 different times (with and without the glenoid vault model present), blindly and in random order. Inter- and intraobserver reliabilities were calculated to assess agreement (slight, fair, moderate, substantial, almost perfect) within groups and by modified Walch classification categories.

RESULTS

Interobserver reliability showed fair to moderate agreement for both groups. Group 1 had a kappa of 0.43 (95% confidence interval [CI]: 0.38, 0.48) with the glenoid vault model absent and 0.41 (95% CI: 0.37, 0.46) with it present. Group 2 had a kappa of 0.38 (95% CI: 0.33, 0.43) with the glenoid vault model absent and 0.37 (95% CI: 0.32, 0.43) with it present. Intraobserver reliability showed substantial agreement for group 1 with (0.63, range 0.47-0.71) and without (0.61, range 0.52-0.69) the glenoid vault model present. For group 2, intraobserver reliability showed moderate agreement with the glenoid vault model absent (0.51, range 0.30-0.72), which improved to substantial agreement with the glenoid vault model present (0.61, range 0.34-0.87).

DISCUSSION

Inter- and intraobserver reliability of the modified Walch classification were fair to moderate and moderate to substantial, respectively, using standardized 3D CT imaging analysis in a large multicenter study. The findings potentially suggest that cases with a spectrum of posterior glenoid bone loss and/or dysplasia can be harder to distinguish by modified Walch type because of a lack of defined thresholds, and the glenoid vault model may be beneficial in determining Walch type in certain scenarios. The ability to reproducibly separate patients into groups based on preoperative pathology, including Walch type, is important for future studies to accurately evaluate postoperative outcomes in TSA patient cohorts.

Total shoulder arthroplasty with an anterior-offset humeral head in patients with a B2 glenoid

Background

To address severe posterior subluxation associated with the Walch B2 glenoid deformity, the eccentricity of the prosthetic humeral head can be reversed, allowing the humerus to remain in a relatively posterior position while the prosthetic humeral head remains well-centered on the glenoid. This study describes the short-term outcomes after anatomic total shoulder arthroplasty (TSA) using this technique.

Methods

We retrospectively reviewed a consecutive series of patients with a B2 glenoid who underwent TSA with the prosthetic eccentric humeral head rotated anteriorly for excessive posterior subluxation noted intraoperatively. Medical records were reviewed for visual analog scale (VAS), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), and Simple Shoulder Test (SST) scores. Final radiographs were analyzed for instability, lesser tuberosity osteotomy healing, and glenoid loosening.

Results

Twenty patients were included with outcome scores at a mean of 48 months. Mean VAS (P < .0001), ASES (P < .0001), and SST (P < .0001) scores improved significantly. Using the Lazarus classification for glenoid loosening, 5 patients had grade 1 lucency and 2 had grade 2 lucency at a mean of 24 months' follow-up. The remaining 13 patients had no glenoid lucencies. Radiographic decentering was reduced from a mean of 9.9% ± 5.7% preoperatively to 0.5% ± 3.0% postoperatively (P < .001). There were no cases of lesser tuberosity repair failures or revision surgery.

Conclusion

TSA in patients with a B2 glenoid with a reversed, anterior-offset humeral head to address residual posterior subluxation resulted in excellent functional outcomes at short-term follow-up with improvement in humeral head centering. Early radiographic follow-up suggests low risks of progressive glenoid lucencies and component loosening.

Risk factors for surgery due to rotator cuff disease in a population-based cohort

AIMS

Few risk factors for rotator cuff disease (RCD) and corresponding treatment have been firmly established. The aim of this study was to evaluate the relationship between numerous risk factors and the incidence of surgery for RCD in a large cohort.

METHODS

A population-based cohort of people aged between 40 and 69 years in the UK (the UK Biobank) was studied. People who underwent surgery for RCD were identified through a link with NHS inpatient records covering a mean of eight years after enrolment. Multivariate Cox proportional hazards regression was used to calculate hazard ratios (HRs) as estimates of associations with surgery for RCD accounting for confounders. The risk factors which were considered included age, sex, race, education, Townsend deprivation index, body mass index (BMI), occupational demands, and exposure to smoking.

RESULTS

Of the 421,894 people who were included, 47% were male. The mean age at the time of enrolment was 56 years (40 to 69). A total of 2,156 people were identified who underwent surgery for RCD. Each decade increase in age was associated with a 55% increase in the incidence of RCD surgery (95% confidence interval (CI) 46% to 64%). Male sex, non-white race, lower deprivation score, and higher BMI were significantly associated with a higher risk of surgery for RCD (all p < 0.050). Greater occupational physical demands were significantly associated with higher rates of RCD surgery (HR = 2.1, 1.8, and 1.4 for 'always', 'usually', and 'sometimes' doing heavy manual labour vs 'never', all p < 0.001). Former smokers had significantly higher rates of RCD surgery than those who had never smoked (HR 1.23 (95% CI 1.12 to 1.35), p < 0.001), while current smokers had similar rates to those who had never smoked (HR 0.94 (95% CI 0.80 to 1.11)). Among those who had never smoked, the risk of surgery was higher among those with more than one household member who smoked (HR 1.78 (95% CI 1.08 to 2.92)). The risk of RCD surgery was not significantly related to other measurements of secondhand smoking.

CONCLUSION

Many factors were independently associated with surgery for RCD, including older age, male sex, higher BMI, lower deprivation score, and higher occupational physical demands. Several of the risk factors which were identified are modifiable, suggesting that the healthcare burden of RCD might be reduced through the pursuit of public health goals, such as reducing obesity and modifying occupational demands. Cite this article: Bone Joint J 2020;102-B(3):352-359.

Ten-day culture incubation time can accurately detect bacterial infection in periprosthetic infection in shoulder arthroplasty

Background

Cutibacterium acnes is the most commonly isolated organism involved in periprosthetic shoulder infections. C acnes has traditionally been difficult to isolate, and much debate exists over appropriate culture methods. Recently, our institution initiated a 10-day culture method using a Brucella blood agar medium to enhance anaerobic growth specifically for C acnes in shoulder specimens.

Methods

A retrospective review of shoulder cultures from 2014-2017 of patients undergoing workup for possible infected shoulder arthroplasty was performed. Cultures were obtained in patients either preoperatively or intraoperatively at the time of revision. Presence of infection was determined based on at least 1 positive culture and treatment with either prolonged antibiotics, placement of an antibiotic spacer at the time of revision, or repeat surgical débridement.

Results

The records of 85 patients with 136 cultures were reviewed. Eighty-two patients had full records with at least 1-year clinical follow-up. Fifty-eight cultures were positive, with C acnes as the most commonly recovered organism (57% of positive cultures). Clinical follow-up of patients with negative cultures found no incidence of missed periprosthetic infection.

Conclusions

Use of a 10-day culture incubation method to enhance anaerobic bacterial growth is able to accurately detect periprosthetic infection in the shoulder including those related to C acnes. Our results suggest that by adopting more uniform culture methods, a shorter culture incubation time may be adequate. Ultimately, prospective studies with rigorous microbiologic methods are needed to best understand the clinical significance of unexpected positive bacterial cultures in shoulder arthroplasty.

Severity of Glenohumeral Osteoarthritis Does Not Correlate With Patient-Reported Outcomes

Background

Patient pain and clinical function are important factors in decision-making for patients with glenohumeral osteoarthritis (GHOA). The correlation between radiographic severity of arthritis and demographic factors with modern patient-reported outcome measures has not yet been well defined.

Methods

This cross-sectional study included 256 shoulders in 246 patients presenting with isolated GHOA. All patients obtained standard radiographs and completed the American Shoulder and Elbow Surgeons score, Simple Shoulder Test (SST), Shoulder Activity Scale, Visual Analog Scale, and Patient-Reported Outcome Measurement Information System (PROMIS) computer adaptive tests at the time of presentation. Radiographs were graded according to the Samilson–Prieto classification. Mean pain and functional scores were compared between the radiographic grades of osteoarthritis (OA) and demographic factors.

Results

There were 6 shoulders rated as grade 1 OA, 41 shoulders as grade 2, 149 shoulders as grade 3a, and 65 shoulders as grade 3b. There was excellent interobserver reliability in grade of OA (κ = 0.77). There were no significant differences in patient-reported pain or any validated measure of clinical function between radiographic grades of OA (P > .05). Males reported higher function and lower pain scores than females (P = .001–.066), although only the values for the SST and PROMIS physical function test were clinically relevant.

Discussion

While gender correlated with pain and function, the clinical relevance is limited. Radiographic severity of GHOA does not correlate with patient-reported pain and function, and symptoms should remain the primary determinants of surgical decision-making. Further investigation is necessary to examine whether radiographic severity of OA influences improvement following operative intervention in this population.

Outpatient narcotic consumption following total shoulder arthroplasty

Introduction

In the setting of the opioid epidemic, physicians continue to scrutinize ways to minimize exposure to narcotic medications. Several studies emphasize improvements in perioperative pain management following total shoulder arthroplasty (TSA). However, there is a paucity of literature describing outpatient narcotic consumption requirements following TSA.

Methods

A single-institution, prospective study of patients undergoing primary TSA was performed. Preoperative demographics including exposure to narcotics, smoking history, and alcohol exposure were collected. The primary outcome was measurement of total outpatient narcotic consumption 6 weeks from surgery. Narcotic consumption was verified by counting leftover pills at the final follow-up visit.

Results

Overall, 50 patients were enrolled. The median narcotic consumption in the cohort was 193 morphine equivalent units (MEUs), approximately 25 (5-mg) tablets of oxycodone, and the mean consumption was 246 MEUs, approximately 32 (5-mg) tablets. Almost 25% of patients consumed fewer than 10 total tablets, with 10% of patients taking no narcotics at home. Multivariate regression found preoperative narcotic exposure associated with increased consumption of 31 MEUs (P = .004). Older age was found to be protective of narcotic consumption, with increasing age by 1 year associated with 0.75 MEU decrease in consumption (P = .04).

Conclusions

Anatomic total shoulder arthroplasty in general provides quick, reliable pain relief and does not require a significant amount of narcotic medication postoperatively. For most patients, it is reasonable to prescribe the equivalent of 25-30 (5-mg) oxycodone tablets following TSA.

Factors associated with choice for surgery in newly symptomatic degenerative rotator cuff tears: a prospective cohort evaluation

BACKGROUND

The patient-related factors for the perceived need for surgery for degenerative rotator cuff tears are not known. The purpose of this study is to examine patient- and tear-specific factors leading to surgery in newly painful degenerative rotator cuff tears.

METHODS

Asymptomatic, degenerative rotator cuff tears were followed prospectively to identify the onset of pain and tear enlargement. Newly painful tears were continually monitored with a focus on identifying patient-specific (age, occupation, activity level) and tear-specific (tear type and size, tear progression, American Shoulder and Elbow Surgeons score, muscle degeneration) factors that are associated with surgical intervention.

RESULTS

Forty-eight of 169 newly painful shoulders were eventually managed surgically. Factors associated with surgical treatment included younger age (P = .0004), pain development earlier in surveillance (P = .0002), a greater increase in pain (P = .0001), a decline in American Shoulder and Elbow Surgeons score (P < .0001), and a history of contralateral shoulder surgery (P = .0006). Eighty-five of the 169 tears (50%) enlarged either before or within 2 years of pain development. Neither tear type (P = .13), tear enlargement (P = .67) nor tear size (P = .51) was associated with surgery. Neither the severity of muscle degeneration, occupational status, hand dominance, Shoulder Activity Score, nor changes in RAND-12 mental or physical scales differed between groups.

DISCUSSION

For newly painful rotator cuff tears, patient-specific factors such as younger age and prior surgery on the contralateral shoulder are more predictive of future surgery than tear-specific factors or changes in tear size over time.

The functional internal rotation scale: a novel shoulder arthroplasty outcome measure

Background

Shoulder arthroplasty, especially reverse shoulder arthroplasty (RSA), continues to increase in volume. Limitations in internal rotation can be challenging following RSA. Current patient-reported outcome measures are limited in assessing a patient's functional internal rotation following shoulder arthroplasty. To address this limitation, a questionnaire was developed.

Methods

A single-center prospective comparative cohort study was performed to determine the reliability of the questionnaire. A pilot group of patients who had at least 1 year of follow-up following shoulder arthroplasty was asked to complete the questionnaire. Reliability testing was performed using Cronbach's alpha test. Additionally, individual questions and total questionnaire scores were compared between patients who underwent anatomic total shoulder arthroplasty (TSA) and RSA.

Results

The questionnaire showed high reliability with all questions. A group of 23 anatomic TSA and 20 RSA patients were compared. RSA patients scored significantly lower on the questionnaire (35.2 out of 50 vs. 43.9, P = .001).

Conclusion

The questionnaire can be used in conjunction with other patient-reported outcome measures to help surgeons better assess patients' results following shoulder arthroplasty. The initial findings from our internal reliability study found that RSA patients had significantly lower scores and higher variability in internal rotation function vs. patients with TSA. Further studies are needed to determine the clinical importance of this questionnaire.

Association Between Rotator Cuff Muscle Size and Glenoid Deformity in Primary Glenohumeral Osteoarthritis

BACKGROUND

Although glenoid morphology has been associated with fatty infiltration of the rotator cuff in arthritic shoulders, the association of rotator cuff muscle area with specific patterns of glenoid wear has not been studied. The purpose of our study was to assess the associations of glenoid deformity in primary glenohumeral osteoarthritis and rotator cuff muscle area.

METHODS

A retrospective study of 370 computed tomographic (CT) scans of osteoarthritic shoulders was performed. Glenoid deformity according to the modified Walch classification was determined, and retroversion, inclination, and humeral-head subluxation were calculated using automated 3-dimensional software. Rotator cuff muscle area was measured on sagittal CT scan reconstructions. A ratio of the area of the posterior rotator cuff muscles to the subscapularis was calculated to approximate axial plane potential force imbalance. Univariate and multivariate analyses to determine associations with glenoid bone deformity and rotator cuff measurements were performed.

RESULTS

Patient age and sex were significantly related to cuff muscle area across glenoid types. Multivariate analysis did not find significant differences in individual rotator cuff cross-sectional areas across glenoid types, with the exception of a larger supraspinatus area in Type-B2 glenoids compared with Type-A glenoids (odds ratio [OR], 1.5; p = 0.04). An increased ratio of the posterior cuff area to the subscapularis area was associated with increased odds of a Type-B2 deformity (OR, 1.3; p = 0.002). Similarly, an increase in this ratio was significantly associated with increased glenoid retroversion (beta = 0.92; p = 0.01) and humeral-head subluxation (beta = 1.48; p = 0.001). Within the Type-B glenoids, only posterior humeral subluxation was related to the ratio of the posterior cuff to the subscapularis (beta = 1.15; p = 0.001).

CONCLUSIONS

Age and sex are significantly associated with cuff muscle area in arthritic shoulders. Asymmetric glenoid wear and humeral-head subluxation in osteoarthritis are associated with asymmetric atrophy within the rotator cuff transverse plane. Increased posterior rotator cuff muscle area compared with anterior rotator cuff muscle area is associated with greater posterior glenoid wear and subluxation. It is unclear if the results are causative or associative; further research is required to clarify the relationship.

LEVEL OF EVIDENCE

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

Autografting for B2 Glenoids

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

The influence of mental health on Patient-Reported Outcomes Measurement Information System (PROMIS) and traditional outcome instruments in patients with symptomatic glenohumeral arthritis

BACKGROUND

The Patient-Reported Outcomes Measurement Information System (PROMIS) assessment includes computerized adaptive tests (CATs) that assess function, pain, depression, and anxiety. The influence of mental health on patients' self-reported pain and function has not been explored using PROMIS in patients with symptomatic glenohumeral osteoarthritis.

METHODS

This cross-sectional study included 284 shoulders in 276 patients presenting with isolated glenohumeral osteoarthritis. All patients completed the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST), Visual Analog Pain Scale (VAS), and PROMIS CATs at the time of presentation. PROMIS anxiety and depression scores were converted into Generalized Anxiety Disorder-7 and Patient Health Questionnaire-9 scores, respectively, using the PROsetta Stone "crosswalk" tool. Mean pain and functional scores were compared between patients with and without PROMIS-converted scores corresponding to a diagnosis of anxiety or depression, as well as between scores corresponding to varying degrees of anxiety or depression.

RESULTS

Patients with scores corresponding to a diagnosis of anxiety or depression reported lower functional and higher pain scores compared to those with scores in the normal range (P < .001). Analysis of variance showed progressively lower functional and higher pain scores as anxiety severity increased (P < .001). Similar results were seen with ASES, upper extremity CAT, and pain scores as depression severity increased (P < .001). Functional ASES (P = .004), SST (P < .001), and physical function CAT (P = .002) scores were statistically significantly lower in patients with moderate to severe depression than those without depression or with mild depression.

DISCUSSION

In patients with glenohumeral osteoarthritis, PROMIS-reported anxiety and depression scores, particularly in those with moderate-to-severe scores, correlate with lower functional and higher pain scores. Further investigation is necessary to examine the influence that mental health has on outcomes after operative intervention in this population.

Editorial Commentary: Progression of Degenerative Full-Thickness Rotator Cuff Tears: Are We Finally Using Natural History Data to Define At-Risk Tears?

Defining and understanding natural history data for any disease is paramount to developing effective treatment strategies: degenerative rotator cuff disease is no different. The natural history defines disease progression without treatment or intervention. Given the persistent variable indications for surgical intervention for painful rotator cuff tears, a more thorough understanding of the rate of progression of full-thickness rotator cuff tears can help to refine surgical indications and potentially define the risks of nonoperative treatment. This systematic review synthesizes existing literature and takes the surgeon one step closer to understanding the rates of tear progression for untreated tears-one small step.

Radiation Therapy-Induced Pathologic Scapula Fracture After Reverse Total Shoulder Arthroplasty: A Case Report

Background

Radiotherapy is widely used as an effective adjunctive treatment modality in conjunction with conservative surgery for breast cancer. Radiation-induced skeletal changes in the shoulder region have been reported in 1% to 3% of patients who have undergone this treatment modality. With treatment techniques improving life expectancy, there is an increasing number of patients undergoing shoulder arthroplasty surgery with a history of cancer radiation therapy. To our knowledge, there are no reports focusing on potential radiation-related pathologic fractures of the shoulder after shoulder arthroplasty.

Case report

We present a case of catastrophic failure of glenoid component fixation after reverse shoulder arthroplasty (RSA) in a patient with previous high-dose radiation to the breast and supraclavicular areas. In this patient, failure of ingrowth of the baseplate and incorporation of the glenoid bone graft lead to eventual component loosening and subsidence. In addition, insufficiency fractures of the scapular body and base of the scapular spine occurred, complicating the clinical situation. The likely cause of these complications stems from radiation-induced impaired bone metabolism directly limiting bone remodeling potential.

Conclusion

This is a rare complication following RSA but highlights a concern that must be considered prior to implantation of the prosthesis that requires bone ingrowth for fixation.

Lesser Tuberosity Osteotomy in Anatomic Total Shoulder Arthroplasty

The deltopectoral exposure has earned the reputation as the “workhorse” approach to the shoulder. Due to the reproducible anatomy and its extensile nature, there is little debate when considering exposure in total shoulder arthroplasty (TSA). Despite this consensus, there is still significant variability in management of the subscapularis. Several repair techniques including a subscapularis tenotomy, peel, and lesser tuberosity osteotomy (LTO) have been developed to ensure healing and optimize function. This article focuses on performing a LTO in anatomic TSA. We will review the surgical technique and advantages in exposure in addition to biomechanical and clinical outcomes.

Do magnetic resonance imaging and computed tomography provide equivalent measures of rotator cuff muscle size in glenohumeral osteoarthritis?

BACKGROUND

Rotator cuff muscle volume is associated with outcomes after cuff repair and total shoulder arthroplasty. Muscle area on select magnetic resonance imaging (MRI) slices has been shown to be a surrogate for muscle volume. The purpose of this study was to determine whether computed tomography (CT) provides an equivalent measurement of cuff muscle area to a previously validated MRI measurement.

METHODS

We included 30 patients before they were undergoing total shoulder arthroplasty with both preoperative CT and MRI scans performed within 30 days of one another at 1 institution using a consistent protocol. We reoriented CT sagittal and MRI sagittal T1 series orthogonal to the scapular plane. On both CT and MRI scans, we measured the area of the supraspinatus, infraspinatus-teres minor, and subscapularis on 2 standardized slices as previously described. We calculated intraclass correlation coefficients and mean differences.

RESULTS

For the 30 subjects included, when MRI and CT were compared, the mean intraclass correlation coefficients were 0.989 (95% confidence interval [CI], 0.976-0.995) for the supraspinatus, 0.978 (95% CI, 0.954-0.989) for the infraspinatus-teres minor, and 0.977 (95% CI, 0.952-0.989) for the subscapularis. The mean differences were 0.2 cm² (95% CI, 0.0-0.4 cm²) for the supraspinatus (P = .052), 0.8 cm² (95% CI, 0.1-1.4 cm²) for the infraspinatus-teres minor (P = .029), and -0.3 cm² (95% CI, -1.2 to 0.5 cm²) for the subscapularis (P = .407).

CONCLUSION

CT provides nearly equivalent measures of cuff muscle area to an MRI technique with previously validated reliability and accuracy. While CT underestimates the infraspinatus area as compared with MRI, the difference is less than 1 cm² and thus likely clinically insignificant.

Risk of Perforation Is High During Corrective Reaming of Retroverted Glenoids: A Computer Simulation Study

BACKGROUND

Corrective anterior reaming is an accepted method for addressing retroversion in a biconcave retroverted (Walch classification, type B2) glenoid in anatomic total shoulder arthroplasty. However, concern still exists regarding early glenoid component failure in the setting of severe retroversion, which may be related to loss of component containment and/or violation of subchondral bone resulting from reaming. The goal of this study was to determine what characteristics of B2 glenoids are less amenable to corrective reaming by virtually implanting anatomic glenoid components.

QUESTIONS/PURPOSES

(1) How much medial reaming is required to correct the version of a B2 glenoid to an acceptable position? (2) Are glenoids with more severe retroversion (> 25°) at higher risk of component perforation than less retroverted glenoids? (3) Is correcting to 10° of retroversion associated with greater risk as compared with reaming to 15°? (4) How does corrective reaming affect the underlying bone density on the glenoid face of B2 glenoids?

METHODS

A series of 71 patients with B2 glenoids (posterior subluxation of the humeral head with posterior bone loss) with CT scans who were indicated for shoulder arthroplasty were reviewed. Forty-four of 71 glenoids (62.5%) had < 25° of native retroversion. Anatomic glenoid implants were then virtually implanted using three-dimensional CT software that allows for preoperative shoulder arthroplasty planning to correct native retroversion to 15° or 10° of retroversion using both a central peg with an inverted triangle peg configuration or a keel. The amount of reaming of the anterior glenoid required to correct retroversion, perforation of peripheral pegs, or keel was compared. Additionally, assessment of the surface area of the glenoid that had poor bone density (defined as cancellous bone under the subchondral plate) was analyzed by the software after correction.

RESULTS

Correction to 15° of retroversion required 5 ± 3 mm of reaming, and correction to 10° of retroversion required 8 ± 3 mm of reaming to obtain at least 80% seating. Peripheral peg perforation with correction to 15° occurred in 15 of 27 (56%) glenoids with > 25° of retroversion compared with 10 of 44 (23%) of glenoids with < 25° of retroversion (relative risk [RR], 2.4; 95% confidence interval [CI], 1.3-4.6; p = 0.006). There was no difference in perforation with keeled components. Increased correction to 10° did not increase the risk of component perforation. When correction to 15°, glenoids with higher native version (> 25°) had a greater risk of poor bone quality support (10 of 27 [37%]) when compared with glenoids with less version (four of 44 [9%]; RR, 4.1; 95% CI, 1.5-12.8; p = 0.006). Increased correction resulted in 13 of 27 (48%) glenoids with version > 25° having poor bone density versus 10 of 44 (23%) with ≤ 25° of version (RR, 2.1; 95% CI, 1.1-4.1; p = 0.028).

CONCLUSIONS

There is a high risk of vault perforation after corrective reaming. Glenoid retroversions > 25° are at a higher risk of having poor bone quality supporting the component.

CLINICAL RELEVANCE

When contemplating options for patients with severe retroversion, surgeons should consider alternatives other than corrective reaming if achieving normal glenoid version is desired.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Does prosthetic humeral articular surface positioning associate with outcome after total shoulder arthroplasty?

BACKGROUND

The purpose of this study was to determine the effect of humeral articular component positioning on changes in patient-reported outcomes after anatomic total shoulder arthroplasty.

METHODS

This was a retrospective series of consecutive patients at 2 high-volume referral centers. The study included patients with (1) a preoperative and postoperative radiograph demonstrating a perfect or nearly perfect profile of the humerus and implant and (2) Simple Shoulder Test, visual analog scale for pain, and American Society of Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment scores preoperatively and at greater than 2 years postoperatively. Head height, head diameter, tuberosity-to-head height distance, inclination, and medial offset of the center of rotation (COR) were measured preoperatively and postoperatively. Distance and direction from the ideal COR to the reconstructed center of rotation was measured. Measurements were correlated with improvement in functional outcomes.

RESULTS

The study included 95 patients, aged 66 ± 9 years, with a mean follow-up of 4.3 ± 1.7 years. An a priori power analysis suggested that a sample size of 95 patients provided 80% power to detect correlations of R² = 0.07. The COR shift was >2 mm in 62% of patients and >4 mm 15%. Thirty-two percent had a change of ASES of <21 points. On multivariate analysis, there were no significant associations between any change in measured prosthetic radiographic parameters and changes in the visual analog scale, Simple Shoulder Test, or ASES scores (P > .05).

CONCLUSION

In this retrospective analysis of total shoulder arthroplasty in which most components were well positioned, humeral component positioning did not associate with change in postoperative outcomes. These findings should be prospectively confirmed.

Natural History of Degenerative Rotator Cuff Tears

PURPOSE OF REVIEW

In the past several years, there have been significant advances in our understanding of the natural history of rotator cuff disease. Studies have continued to provide valuable insight into the clinical, radiographic, and anatomic features of these atraumatic tears. Our purpose is to summarize the findings and contributions from these recent high-quality studies.

RECENT FINDINGS

Current research has continued to describe and provide understanding into the natural history of atraumatic rotator cuff disease, including symptom progression, tear enlargement, and the development of arthritis. This knowledge has allowed identification of tears with higher risk of disease progression. Additionally, studies have investigated, with long-term healing data, whether the natural history of degenerative rotator cuff tears can be altered with surgical intervention. Recent studies have shown encouraging mid to long-term healing data and clinical outcome scores for smaller tears in younger patients with minimal fatty infiltration. Future research should focus on obtaining long-term healing data, functional outcome data, and refining surgical indications for rotator cuff repair. Identifying patients with specific tear characteristics amendable to healing will allow us to provide a long-term, durable repair, thus interrupting the natural history of degenerative rotator cuff disease.

Optimizing reverse shoulder arthroplasty component position in the setting of advanced arthritis with posterior glenoid erosion: a computer-enhanced range of motion analysis

BACKGROUND

Our study purpose was to determine the optimal glenoid and humeral reverse shoulder arthroplasty (RSA) component design and position in osteoarthritic shoulders with severe glenoid retroversion deformities.

METHODS

Computed tomography scans from 10 subjects were analyzed with advanced software including RSA range of motion (ROM) analysis. Variables included glenoid component retroversion of 0°, 5°, 10°, 15°, and 20° and baseplate lateralization of 0, 5, and 10 mm. Humeral variables included 135°, 145°, and 155° angle of inclination (AOI) combined with variable humeral offset.

RESULTS

Glenoid component lateralization had the greatest influence on ROM. In comparing each ROM direction among all lateralization options independently, there were significantly greater adduction, abduction, external rotation, extension, and flexion motions with progressively greater lateralization. Internal rotation motion was greater at 10 mm only. In analyzing the effects of glenoid version independently, no differences in adduction or abduction ROM were seen. With greater retroversion, decreased external rotation and extension motion was noted; however, greater internal rotation and flexion motion was seen with the exception of flexion at 10 mm of lateralization. For adduction, external rotation, and extension, a more valgus AOI resulted in less ROM at each progressively greater AOI independent of humeral lateralization. Internal rotation and flexion motions were greater with a more varus AOI but not significant between each inclination angle. Abduction ROM was maximized with a more valgus AOI. Humeral lateralization had no effect on ROM.

CONCLUSIONS

In the setting of RSA for advanced glenoid osteoarthritic deformities, optimal ROM is achieved with 10-mm baseplate lateralization and neutral to 5° of retroversion mated to a humeral implant with a varus (135°) inclination angle.

Continuous interscalene brachial plexus blockade is associated with reduced length of stay after shoulder arthroplasty

BACKGROUND

Catheter-delivered continuous interscalene anesthesia has demonstrated improved pain control in randomized clinical trials. The purpose of this study is to determine whether the introduction of continuous catheter anesthesia was associated with a change in length of stay (LOS), readmission, rates of discharge home without home health or nursing services, or opioid administration. We hypothesized that the introduction of continuous catheter anesthesia would be associated with a decrease in LOS, readmission, non-home discharge, and opioid administration.

METHODS

During 2012, our center transitioned from ultrasound-guided single-dose interscalene regional anesthesia to combined single-dose anesthesia and additional continuous catheter anesthesia over 48-72hours. This retrospective chart review compared primary shoulder arthroplasties with single-dose anesthesia to those with continuous catheter anesthesia, after excluding the learning curve, with univariate and multivariate analyses.

RESULTS

In total, 1697 patients met criteria, 41% with single-dose anesthesia and 59% with continuous catheter anesthesia. On univariate analysis, the continuous catheter group LOS was 2.2±0.7 day and single-dose group LOS was 2.5±0.8 days (P≤0.001). One day LOS's comprised 1% of the single-dose group and 27% of the continuous catheter group (P<0.001). Anesthesia type remained a significant predictor on multivariate analysis (P<0.001) Readmission at 30 and 90 days (P=0.091 and 0.576), and home discharge (P=0.456) were not different. Opioid administration was higher in the continuous catheter group on univariate analysis (P<0.001), but not on multivariate analysis (P=0.607).

CONCLUSION

In this retrospective review of 1697 primary shoulder arthroplasties performed at our high-volume, referral center, continuous catheter anesthesia was associated with reduced length of stay when compared to single-dose anesthesia.

LEVEL OF EVIDENCE

Therapeutic, level IV.

Shoulder activity level and progression of degenerative cuff disease

BACKGROUND

This study prospectively examined the relationship of direct and indirect measures of shoulder activity with the risks of tear progression and pain development in subjects with an asymptomatic degenerative rotator cuff tear.

METHODS

A cohort of asymptomatic degenerative rotator cuff tears was prospectively monitored annually, documenting tear size progression with ultrasound imaging and potential shoulder pain development. Shoulder activity level, self-reported occupational and physical demand level, and hand dominance were compared with risks of tear enlargement and future pain development.

RESULTS

The study monitored 346 individuals with a mean age of 62.1 years for a median duration of 4.1 years (interquartile range [IQR], 2.4-7.9 years). Tear enlargement was seen in 177 shoulders (51.2%), and pain developed in 161 shoulders (46.5%) over time. Tear presence in the dominant shoulder was associated with a greater risk of tear enlargement (hazard ratio, 1.40; P = .03) and pain development (hazard ratio, 1.63; P = .002). Shoulder activity level (P = .37) and occupational demand level (P = .62) were not predictive of tear enlargement. Occupational demand categories of manual labor (P = .047) and "in between" (P = .045) had greater risks of pain development than sedentary demands. The median shoulder activity score for shoulders that became painful was lower than for shoulders that remained asymptomatic (10.0 [IQR, 7.0-13.0] vs. 11.0 [IQR, 8.0-14.0], P = .02).

CONCLUSIONS

Tear enlargement and pain development in asymptomatic tears are more common with involvement of the dominant shoulder. Shoulder activity level is not related to tear progression risks. Pain development is associated with a lower shoulder activity level even though patients with higher occupational demands are more likely to develop pain.

Dislocation following reverse total shoulder arthroplasty

BACKGROUND

The etiology of instability following reverse total shoulder arthroplasty (RTSA) remains incompletely understood. The purpose of this study was to describe the shared characteristics, etiologies, and outcomes of early and late dislocations requiring operative revision.

METHODS

We identified all patients at our institution who underwent operative revision of an RTSA for instability. Baseline demographic, clinical, and radiographic data were collected. Standardized outcome scores were collected preoperatively and at final follow-up. Characteristics of dislocations that occurred less than 3 months postoperatively (early) were compared with those that occurred more than 3 months postoperatively (late).

RESULTS

Twenty-two patients met the criteria, and follow-up was obtained on 19 patients at 4.9 ± 2.5 years, with 14 early and 5 late dislocations. Most patients in both groups were men, were aged over 70 years, and had a history of shoulder surgery. On analysis of instability etiology, 68% had inadequate soft-tissue tensioning (10% due to partial axillary nerve injuries). The remaining patients had asymmetric liner wear, mechanical liner failure, or impinging heterotopic ossification. Asymmetric liner wear accounted for 60% of late dislocations. Recurrent instability after revision was present in 29% of early and 40% of late dislocators.

DISCUSSION

No significant differences in outcomes or recurrence rates were found for early and late dislocations. Of the late dislocations, 80% had evidence of adduction impingement, via either heterotopic ossification or asymmetric polyethylene wear. Post-RTSA instability had 2 distinct etiologies: (1) instability due to inadequate soft-tissue tensioning and/or axillary nerve palsy and (2) instability due to impingement or liner failure.

Progression of Fatty Muscle Degeneration in Atraumatic Rotator Cuff Tears

BACKGROUND

The purpose of this prospective study was to examine the progression of fatty muscle degeneration over time in asymptomatic shoulders with degenerative rotator cuff tears.

METHODS

Subjects with an asymptomatic rotator cuff tear in 1 shoulder and pain due to rotator cuff disease in the contralateral shoulder were enrolled in a prospective cohort. Subjects were followed annually with shoulder ultrasonography, which evaluated tear size, location, and fatty muscle degeneration. Tears that were either full-thickness at enrollment or progressed to a full-thickness defect during follow-up were examined. A minimum follow-up of 2 years was necessary for eligibility.

RESULTS

One hundred and fifty-six shoulders with full-thickness rotator cuff tears were potentially eligible. Seventy shoulders had measurable fatty muscle degeneration of at least 1 rotator cuff muscle at some time point. Patients with fatty muscle degeneration in the shoulder were older than those without degeneration (mean, 65.8 years [95% confidence interval (CI), 64.0 to 67.6 years] compared with 61.0 years [95% CI, 59.1 to 62.9 years]; p < 0.05), and the median size of the tears at baseline was larger in shoulders with degeneration than in shoulders that did not develop degeneration (13 and 10 mm wide, respectively, and 13 and 10 mm long; p < 0.05). Tears with fatty muscle degeneration were more likely to have enlarged during follow-up than were tears that never developed muscle degeneration (79% compared with 58%; odds ratio, 2.64 [95% CI, 1.29 to 5.39]; p < 0.05). Progression of fatty muscle degeneration occurred more frequently in shoulders with tears that had enlarged (43%; 45 of 105) than in shoulders with tears that had not enlarged (20%; 10 of 51; p < 0.05). Additionally, tears with enlargement and progression of muscle degeneration were more likely to extend into the anterior supraspinatus than were those without progression (53% and 17%, respectively; p < 0.05); however, this relationship was lost when controlling for tear size (p = 0.56). The median time from tear enlargement to progression of fatty muscle degeneration was 1.0 year (range, -2.0 to 6.9 years) for the supraspinatus and 1.1 years (range, -1.8 to 8.5 years) for the infraspinatus muscle (p = 0.98).

CONCLUSIONS

Progression of fatty muscle degeneration is more common in tears that are larger at baseline, enlarge over time, and undergo a larger magnitude of enlargement. Our study findings also suggest that an often rapid progression of muscle degeneration occurs in relation to a clinically relevant increase in tear size in some degenerative cuff tears.

LEVEL OF EVIDENCE

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

Radiographic characterization of the B2 glenoid: is inclusion of the entirety of the scapula necessary?

BACKGROUND

Computed tomography (CT) scans are often obtained before total shoulder arthroplasty to assess glenoid deformity. To allow correction of the slice axis into the plane of the scapula, these scans have typically required inclusion of the entirety of the scapula. The purpose of this study was to determine whether inclusion of the medial border and inferior angle is necessary for accurate measurement of scapular version, inclination, and humeral subluxation.

METHODS

Fourteen CT scans in preoperative total shoulder arthroplasty patients with Walch B2 type glenoids underwent a standardized measurement protocol. Glenoid version, inclination, depth, and humeral subluxation were measured on 2-dimensional CT images corrected to the plane of the scapula. These measurements were then repeated in randomized, blinded fashion after subtracting 12.5%, 25%, and 50% of the scapula from the medial border and 12.5%, 25%, and 50% of the scapula from the inferior angle.

RESULTS

Measurement of retroversion did not significantly differ between measurement of the full scapula and measurement of any of the incomplete scapulas, with the exception of the subtraction of 50% of the scapular width, which caused retroversion to be overestimated by 4.7° (P = .006) and led to inaccurate measurement of subluxation and glenoid depth.

CONCLUSION

If at least 8 cm of scapular width is imaged on a CT scan, accurate glenoid measurements can be made. Even if 50% of scapular height is not imaged, accurate measurements can be made. Failure to include the medial border or inferior angle does not preclude accurate glenoid measurement.

Determining the minimal clinically important difference for the American Shoulder and Elbow Surgeons score, Simple Shoulder Test, and visual analog scale (VAS) measuring pain after shoulder arthroplasty

BACKGROUND

Minimal clinically important differences (MCIDs) for the American Shoulder and Elbow Surgeons (ASES) score, the Simple Shoulder Test (SST), and a visual analog scale (VAS) measuring pain have not been previously described using an anchor-based method after shoulder arthroplasty. The purpose of this study was to determine the MCIDs for these measures after shoulder arthroplasty for glenohumeral arthritis or advanced rotator cuff disease.

METHODS

Primary anatomic total shoulder arthroplasty (TSA), primary reverse TSA, or hemiarthroplasty was performed in 326 patients by 1 of 5 shoulder and elbow surgeons. The SST score, ASES score, and VAS pain score were collected preoperatively and at a minimum of 2 years postoperatively (mean, 3.5 years). The MCIDs were calculated for the ASES score, SST score, and VAS pain score using an anchor-based method.

RESULTS

The MCIDs for the ASES score, SST score, and VAS pain score were 20.9 (P < .001), 2.4 (P < .0001), and 1.4 (P = .0158), respectively. Duration of follow-up and type of arthroplasty (anatomic TSA vs reverse TSA) did not have a significant effect on the MCIDs (P > .1) except shorter follow-up correlated with a larger MCID for the ASES score (P = .0081). Younger age correlated with larger MCIDs for all scores (P < .024). Female sex correlated with larger MCIDs for the VAS pain score (P = .123) and ASES score (P = .05).

CONCLUSIONS

Patients treated with a shoulder arthroplasty require a 1.4-point improvement in the VAS pain score, a 2.4-point improvement in the SST score, and a 21-point improvement in the ASES score to achieve a minimal clinical importance difference from the procedure.