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.