Utility of Recovery Room vs Post-Operative Day 1 Radiographs Following Shoulder Arthroplasty.

Background: Postoperative radiographs may be performed on different timelines after shoulder arthroplasty. Radiographs obtained in the post-operative recovery unit (PACU) are often of poorer quality. The purpose of the current study was to explore and compare the quality of PACU radiographs and radiographs performed in the radiology suite on post-operative Day 1 (POD1), as well as determine their impact on changes in post-operative management. Methods: Our series included 50 consecutive anatomic total shoulder arthroplasties (TSA) for which post-operative radiographs were obtained in the PACU and 50 consecutive TSA for which post-operative radiographs were obtained in the radiology suite on POD 1. TSA radiographs were blinded and reviewed by 3 authors and graded on their quality using criteria described using previously published methods. The weighted kappa was used to describe the intra-rater agreement and inter-rater agreement between two raters. Results: There was no difference in age, sex, BMI, and comorbidities between cohorts. Intra-observer reliability was moderate to substantial with weighted kappa values of 0.65±0.07 (p<0.001), 0.58±0.09 (p<0.001), and 0.67±0.07 (p<0.001). Inter-observer reliability was moderate to substantial with weighted kappa values of 0.605±0.07 (p<0.001), 0.66±0.07 (p<0.001), and 0.65±0.08 (p<0.001). When assessing quality of radiographs, 30% of radiographs obtained in PACU were deemed quality while 57% of radiographs obtained in the radiology suite were deemed quality (p<0.001). Conclusion: Post-operative radiographs in the PACU do not alter patient management and are often inadequate to serve as baseline radiographs. Conversely, radiographs obtained in the radiology suite are of higher quality and can serve as a superior baseline radiograph. Level of Evidence: IV.

Arthroscopic scapulothoracic bursectomy with and without superomedial angle scapuloplasty: a comparison of patient-reported outcomes.

BACKGROUND: Operative treatment of scapulothoracic bursitis most commonly comprises arthroscopic scapulothoracic bursectomy with or without partial superomedial angle scapuloplasty. There is currently no consensus regarding whether or when scapuloplasty should be performed. Prior studies are limited to small case series, and optimal surgical indications are not yet established. The purposes of this study were (1) to retrospectively review patient-reported outcomes of arthroscopic treatment of scapulothoracic bursitis and (2) to compare outcomes between scapulothoracic bursectomy alone and bursectomy with scapuloplasty. We hypothesized that bursectomy with scapuloplasty would provide superior pain relief and functional improvement. MATERIALS AND METHODS: All cases of scapulothoracic débridement with or without scapuloplasty completed at a single academic center from 2007 through August 2020 were reviewed. Patient demographic characteristics, symptomatology data, physical examination findings, and corticosteroid injection response data were collected from the electronic medical record. Visual analog scale pain, American Shoulder and Elbow Surgeons, Simple Shoulder Test, and Single Assessment Numeric Evaluation scores were collected. Comparisons between the group undergoing bursectomy alone and the group undergoing bursectomy with scapuloplasty were made using the Student t test for continuous variables and the Fisher exact test for categorical variables. RESULTS: Thirty patients underwent scapulothoracic bursectomy alone, and 38 patients underwent bursectomy with scapuloplasty. Final follow-up data were available for 56 of 68 cases (82%). Final postoperative visual analog scale pain scores (3.4 ± 2.2 and 2.8 ± 2.2, respectively; P = .351), American Shoulder and Elbow Surgeons scores (75.8 ± 17.7 and 76.5 ± 22.5, respectively; P = .895), and Simple Shoulder Test scores (8.8 ± 2.3 and 9.5 ± 2.8, respectively; P = .340) were similar between the bursectomy-alone and bursectomy-with-scapuloplasty groups. CONCLUSION: Both arthroscopic scapulothoracic bursectomy alone and bursectomy with scapuloplasty are effective treatments for scapulothoracic bursitis. Operative time is shorter without scapuloplasty. In this retrospective series, these procedures showed similar outcomes regarding shoulder function, pain, surgical complications, and rates of subsequent shoulder surgery. Further studies with a focus on 3-dimensional scapular morphology may help optimize patient selection for each of these procedures.

Rotator cuff muscle imbalance associates with shoulder instability direction.

BACKGROUND: Although muscle weakness and/or imbalance of the rotator cuff are thought to contribute to the development of shoulder instability, the association between muscular dysfunction and shoulder instability is not completely understood. The purpose of this study was to evaluate rotator cuff and deltoid muscle cross-sectional areas in different types of shoulder instability (anterior, posterior, and multidirectional instability [MDI]) and to determine the associations between muscular imbalance and shoulder instability direction. METHODS: Preoperative magnetic resonance images of patients with shoulder instability who subsequently underwent arthroscopic glenohumeral labral repair or capsular plication were evaluated. Shoulder instability was classified into 3 categories by direction: (1) anterior, (2) posterior, and (3) MDI. The rotator cuff (supraspinatus, subscapularis, and infraspinatus + teres minor) and deltoid (anterior and posterior portions, and total) muscle areas were measured on T1 sagittal and axial slices, respectively. The ratios of the subscapularis to infraspinatus + teres minor area and the anterior deltoid to posterior deltoid area were calculated to quantify the transverse force couple imbalance. RESULTS: A total of 189 patients were included, where each group consisted of 63 patients. The infraspinatus + teres minor muscle area was smaller than the subscapularis muscle area in the anterior instability group (P = .007). The subscapularis muscle area was smaller than the infraspinatus + teres minor muscle area in the posterior instability and MDI groups (P ≤ .003). The anterior deltoid muscle area was smaller than the posterior deltoid muscle area in all groups (P ≤ .001). The subscapularis-to-infraspinatus + teres minor area ratio in the anterior instability group (1.18 ± 0.40) was higher than that in the posterior instability and MDI groups (0.79 ± 0.31 and 0.93 ± 0.33, respectively; P < .001). There was no difference in the anterior deltoid-to-posterior deltoid area ratio among the 3 groups. CONCLUSION: Patients with anterior instability have smaller muscle area of the posterior rotator cuff as compared with the anterior rotator cuff. In contrast, patients with posterior instability and MDI have smaller muscle area of the anterior rotator cuff as compared with the posterior rotator cuff. Thus, the direction of shoulder instability is associated with rotator cuff muscle area.

Significant Factors of High Performance Outcomes for Tibial Plafond Fractures.

BACKGROUND: Limited research exists about high performance postsurgical tibial plafond fractures. This study aimed to identify aspects of the plafond fracture injury and care associated with "high performance" based on Patient Reported Outcome Measurement Information System (PROMIS) Physical Function (PF) scores. METHODS: Tibial plafond fracture patients with minimum 12-month follow-up treated at a level 1 trauma center from 2006 to 2019 were categorized into high (top 25%) vs average-low (AL) (bottom 75%) performers based on PROMIS PF scores. Demographics and fracture characteristics of high and AL performers were compared. Variables with a P value less than .1 were used in stepwise logistic regressions. RESULTS: The final cohort of 198 patients was divided into high (n=51) and AL (n=147) performers based on PF scores. The mean PF scores for the high and AL groups were 58 (SD=5.3) and 41.9 (SD=6.5), respectively. The mean PROMIS Pain Interference scores for the high performers and AL were 43.3 (SD=4.9) and 56.8 (SD=8.6) (P < .001), respectively. FAAM activities of daily living (high 95.4 [SD=5.5] vs AL 70.4 [SD=19.8], P < .001) and FAAM sports (high 76.8 [SD=21.3] vs AL 27.3 [SD=28.9], P < .001) subscale scores were significantly greater in the high-performing group. Sex, age, marital status, and diabetes were nonsignificant factors in univariate analysis. Significant demographic factors associated with high performance from univariate analysis were Caucasian race, private insurance, no tobacco use, lower body mass index (BMI), and mechanism of injury. Patients with fracture characteristics of OTA 43C (complete articular) fractures, bone loss, open fractures, or nonexcellent reduction were significantly less likely to be high performers. Additionally, less than excellent reductions were more common in more complex fracture patterns. Multivariable regression modeling showed that higher BMI, OTA/AO 43-C (complete articular) fracture classification, and open fracture were significant independent risk factors for reducing likelihood of high performance. CONCLUSION: Significant independent factors associated with high performance after tibial plafond fracture are lower BMI, closed fracture, and OTA/AO 43-B (partial articular) fracture.

Can magnetic resonance imaging accurately and reliably measure humeral cortical thickness?

BACKGROUND: Historically, imaging osseous detail in three dimensions required a computed tomography (CT) scan with ionizing radiation that poorly visualizes the soft tissues. The purpose of this study was to determine the accuracy and reliability of ultrashort echo time (UTE) magnetic resonance imaging (MRI) in measuring humeral cortical thickness and cancellous density as compared with CT. METHODS: This was a comparative radiographic study in nine cadavers, each of which underwent CT and UTE MRI. On images aligned to the center of the humeral shaft, anterior, posterior, medial, and lateral humeral cortical thickness was measured 5, 10, and 15 cm distal to the top of the head. Cancellous density was measured as signal within a 1-cm diameter region of interest in the center of the head, the subtuberosity head, the subarticular head, and the subarticular glenoid vault. Glenoid cortical thickness was measured at the center of the glenoid. Cortical measurements were compared using mean differences and 95% confidence intervals, paired Student's t-tests, and intraclass correlation coefficients (ICCs). We compared cancellous measurements using Pearson's correlation coefficients. For all measurements, we calculated interobserver and intraobserver reliability using ICCs with 0.75 as the lower limit for acceptability. RESULTS: With regard to accuracy, for humeral cortical thickness measurements, there were no significant differences between MRI and CT measures, and ICCs were >0.75. The glenoid cortical thickness ICC was <0.75. There was no significant correlation between the cancellous signal on MRI and on CT in any region. For both MRI and CT, interobserver reliability and intraobserver reliability were acceptable (ie, >0.75) for almost all humeral cortical thickness measures. CONCLUSION: UTE MRI can reliably and accurately measure humeral cortical thickness, but cannot accurately measure cancellous density or accurately and reliably measure glenoid cortical thickness.

Syndesmotic Injury in Tibial Plafond Fractures Is Associated With Worse Patient Outcomes.

OBJECTIVES: To present long-term patient-reported outcomes of tibial plafond fractures with and without concomitant ankle syndesmotic injury. DESIGN: Retrospective cohort study. SETTING: Academic Level 1 trauma center. PATIENTS/PARTICIPANTS: One hundred ninety-seven patients with tibial plafond fractures (OTA/AO 43-B and 43-C) treated with definitive surgical fixation were contacted by telephone or email to obtain patient-reported outcome scores at a minimum follow-up of 1 year. Of those contacted, 148 (75%) had an intact syndesmosis, whereas 49 (25%) experienced a syndesmotic injury. INTERVENTION: The intervention involved open reduction internal fixation of the tibial plafond with syndesmosis repair when indicated. MAIN OUTCOME MEASUREMENT: The main outcome measurement included patient-reported ankle pain and function using Patient-Reported Outcomes Measurement Information System (PROMIS) pain interference and physical function (PF). RESULTS: The cohort including patients with syndesmotic injury had significantly more open fractures (syndesmotic injury = 39%, no syndesmotic injury = 16%, P = 0.001), higher rates of end-stage reconstruction (syndesmotic injury = 27%, no syndesmotic injury = 10%, P = 0.004), and worse PROMIS PF (syndesmotic injury = 42.5 [SD = 8.0], no syndesmotic injury = 47.1 [SD = 9.6], P = 0.045) scores at final follow-up when compared with the cohort comprising patients with no syndesmotic injury. Patients with syndesmotic injury trended toward higher rates of postoperative infection, but this association was not statistically significant. There was no difference between the groups in nonunion or PROMIS pain interference scores. CONCLUSION: Patients with a tibial plafond fracture and concomitant syndesmotic injury had significantly worse PROMIS PF scores, more end-stage ankle reconstructions, and more open fractures. Syndesmotic injury in the setting of tibial plafond fractures portends worse patient outcomes. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

COVID-19-related rotator cuff repair delay.

BACKGROUND: Although nonoperative treatment is effective for degenerative rotator cuff tears (RCTs), it remains unclear whether the delay created by a trial of nonoperative treatment negatively influences the outcome of a subsequent surgical repair. In March 2020, the COVID-19 pandemic resulted in an involuntary delay in the surgical treatment of rotator cuff disease, creating a natural experiment. The purpose of this study was to evaluate the outcomes and healing of patients who underwent delayed surgical treatment of chronic degenerative RCTs as compared with the nondelayed surgical treatment of RCTs. METHODS: This was a prospective study of two groups: patients planned to undergo arthroscopic rotator cuff repair between March 16, 2020 and May 1, 2020-the end of the ban on elective surgery-and patients who underwent rotator cuff repair starting six weeks after the ban on elective surgery had been lifted. Preoperatively and at six months postoperatively, we collected the Simple Shoulder Test, the American Shoulder and Elbow Surgeons (ASES) score, and the visual analog scale for pain. We also obtained magnetic resonance imaging (MRI) at six months postoperatively. A power analysis was conducted, and assuming a mean ± standard deviation ASES score of 93.1 ± 13.9 points and a minimum clinically important difference in the ASES score of 27.1 points, 7 patients per group (14 patients in total) would be necessary to have 90% chance of finding a difference. RESULTS: We included 15 patients within each group and obtained 100% follow-up at six months. In the delay group, the mean ± standard deviation delay was 63 ± 24 days. There were no significant preoperative differences between groups in demographics or tear characteristics. Intraoperatively, there were no differences between groups in repair characteristics. Using a repeated-measures analysis of variance, there were significant preoperative vs. postoperative differences in ASES scores (P < .001), visual analog scale scores (P < .001), and Simple Shoulder Test scores (P < .001), but no differences between groups (P = .910, .519, and 0.852, respectively). On MRI, within the delay group, 58% had healed, whereas within the control group, 85% had healed (P = .202). CONCLUSION: COVID-19 caused a two-month delay in the operative treatment of RCTs. This delay did not significantly alter patient-reported outcomes. This delay resulted in a 27% difference in MRI healing rates, which was not statistically significant in this small study. Larger studies should be conducted as our results suggest that a delay in treatment may negatively impact healing rates.

Surgical Management of Superior Labral Tears in Athletes: Focus on Biceps Tenodesis.

Superior labrum anterior-posterior (SLAP) lesions are common in overhead athletes. Though some patients have asymptomatic lesions, many tears cause pain and diminished athletic performance. Accurate diagnosis of SLAP lesions can be challenging as the sensitivity and specificity of both the physical exam and advanced imaging is questionable. Management is also difficult, as treatment can be life-altering or career-ending for many athletes. If first-line nonoperative treatment fails, surgical options may be considered. The optimal surgical management of SLAP lesions in athletes is debated. Historically, return to play (RTP) rates among athletes who have undergone arthroscopic SLAP repair have been unsatisfactory, prompting clinicians to seek alternate surgical options. Biceps tenodesis (BT) has been postulated to eliminate biceps tendon-related pain in the shoulder and is increasingly used as a primary procedure for SLAP lesions. The purpose of this text is to review the current literature on the surgical management of SLAP lesions in athletes with an emphasis on the role of BT.

Glenoid retroversion associates with deltoid muscle asymmetry in Walch B-type glenohumeral osteoarthritis.

BACKGROUND: The etiologies of glenohumeral osteoarthritis (GHOA) and eccentric glenoid wear within GHOA are unknown, but muscular imbalance may play a role. The purpose of the present study was to determine the relationship between deltoid muscle area, GHOA, and eccentric glenoid wear. We hypothesized that patients with GHOA would have overall deltoid atrophy as compared with controls and that increasing posterior deltoid areas would associate with glenoid retroversion in the Walch B-type (eccentric) GHOA group. METHODS: The study was a retrospective review of computed tomography imaging studies. We included a control group of subjects without GHOA and a group of individuals with GHOA before undergoing total shoulder arthroplasty. We assigned Walch types via consensus. Cross-sectional area was measured for the anterior and posterior deltoid musculature demarcated via the scapular line, normalized to the total deltoid area. Absolute and normalized total, anterior, and posterior deltoid areas were compared between controls and the entire GHOA group. Normalized anterior and posterior deltoid areas were compared between Walch A-type and B-type GHOA patients within the GHOA group. Univariate linear regression was used to evaluate for an association between glenoid retroversion and normalized posterior deltoid areas in controls, Walch A-type, and Walch B-type patients. Multivariate linear regression analysis was used to evaluate the effects of normalized posterior deltoid area, age, sex, and height on glenoid retroversion within the Walch B-type subgroup. RESULTS: We included 99 patients with GHOA and 47 controls. The control and GHOA patients did not differ in absolute deltoid areas (21.8 ± 8.8cm2 vs. 20.6 ± 7.9cm2; P = .488). Patients with GHOA had a statistically significant increase in normalized posterior deltoid area (0.50 ± 0.10 vs. 0.46 ± 0.10; P = .032) and a reciprocal decrease in normalized anterior deltoid area (0.50 ± 0.10 vs. 0.54 ± 0.10; P = .040) compared with controls. Walch A-type and B-type patients did not differ in normalized posterior deltoid areas (0.50 ± 0.11 vs. 0.50 ± 0.10; P = .780). Normalized posterior deltoid area positively associated with glenohumeral retroversion in Walch B-type GHOA (R2 = 0.102; P = .020), a relationship maintained in multivariate linear regression, using gender, age, and height as covariates (standardized beta = 0.309, P = .027). CONCLUSION: GHOA is not associated with deltoid atrophy, calling into question the suggestion that periarticular muscular atrophy in GHOA is secondary to disuse. Increasing normalized posterior deltoid area associates with increased glenoid retroversion in patients with Walch B-type glenoid morphology. Muscular imbalance may play a role in the etiology or progression of the glenoid deformity observed in eccentric GHOA.

Conjoint tendon release for persistent anterior shoulder pain following reverse total shoulder arthroplasty.

BACKGROUND: Persistent anterior shoulder pain is an under-reported complication after reverse total shoulder arthroplasty (RTSA). The purpose of this study was to determine the effectiveness of open conjoint tendon release in patients with anterior shoulder pain due to conjoint tendinitis after RTSA. METHODS: Open conjoint tendon release was performed by the senior author from June 2014 to November 2018 in patients with persistent anterior shoulder pain after RTSA. Patients were evaluated preoperatively and at a minimum of 1 year postoperatively by phone interview with patient-reported outcome scores including a visual analog scale score for pain and the American Shoulder and Elbow Surgeons score. RESULTS: We evaluated 11 of 12 patients (92% follow-up) at a minimum of 1 year (average, 27 ± 11 months) after conjoint tendon release. American Shoulder and Elbow Surgeons and visual analog scale pain scores improved from 29.0 ± 22.1 and 7.3 ± 2.0, respectively, preoperatively to 58.2 ± 30.6 and 3.1 ± 3.5, respectively, postoperatively, after open conjoint tendon release (P = .02 and P = .003, respectively). Of the patients, 45% (5 of 11) reported improvement but with some coracoid pain after the release whereas 55% (6 of 11) reported no coracoid pain after the release. No complications occurred as a result of the release, and no patients required reoperation. CONCLUSION: Our results suggest that conjoint tendinitis may be a cause of persistent postoperative anterior shoulder pain after RTSA and open conjoint tendon release is a successful treatment.

Double-loaded suture anchors in the treatment of anteroinferior glenohumeral instability.

HYPOTHESIS: The purpose of this study was to determine the clinical outcomes of arthroscopic labral repair for anteroinferior glenohumeral instability with the use of double-loaded suture anchors. METHODS: This study evaluated a series of consecutive patients treated after the senior author changed from single- to double-loaded suture anchors for the treatment of anteroinferior glenohumeral instability with a minimum follow-up period of 2 years. We collected the following outcomes at final follow-up: visual analog scale pain score, Simple Shoulder Test score, American Shoulder and Elbow Surgeons score, and instability recurrence data. RESULTS: A total of 41 consecutive patients underwent arthroscopic labral repair with double-loaded anchors, of whom 30 (71%) were able to be contacted at a minimum of 2 years postoperatively. These patients included 4 contact or collision athletes (13%). The patients had an average of 12 ± 13 prior dislocations over an average period of 56 ± 57 months preoperatively. Mean glenoid bone loss measured 16% ± 10%, and 67% (18 of 27 patients) had glenoid bone loss ≥ 13.5%. Intraoperatively, 3.2 ± 0.4 anchors were used. No posterior repairs or remplissage procedures were performed. At an average of 6.7 ± 2.7 years' follow-up, the visual analog scale pain score was 0.8 ± 1.4; Simple Shoulder Test score, 11 ± 2; and American Shoulder and Elbow Surgeons score, 90 ± 14. Patients with bone loss < 13.5% had a 0% redislocation rate and 11% subluxation rate, whereas those with bone loss ≥ 13.5% had a 6% reoperation rate, 22% redislocation rate, and 22% subluxation rate. CONCLUSION: Arthroscopic labral repair with double-loaded anchors provides satisfactory clinical results at early to mid-term outcome assessment when glenoid bone loss is <13.5%.

Revision anterior glenohumeral instability: is arthroscopic treatment an option?

BACKGROUND: The purpose of this study was to determine the short-term outcomes for patients who underwent revision surgery for shoulder instability, including both revision arthroscopic repair and Latarjet. METHODS: This study included patients who underwent revision of a prior arthroscopic labral repair to arthroscopic labral repair or Latarjet at our institution from 2012 to 2017. After collection of preoperative demographic data, preoperative 3-dimensional imaging was reviewed to determine percent glenoid bone loss (%GBL) and to determine whether each shoulder was on-track or off-track. Patients were contacted to obtain postoperative patient-reported outcome metrics including visual analog scale pain, Simple Shoulder Test, American Shoulder and Elbow Surgeons scores, and instability recurrence (full dislocation, subluxation, or subjective apprehension) data at a minimum of 2 years postoperatively. RESULTS: Of 62 patients who met criteria, 45 patients were able to be contacted. Of them, 21 underwent revision arthroscopy and 24 underwent a Latarjet procedure. In the revision arthroscopy group, 5 of 15 had %GBL >20% and 4 of 21 were contact athletes. In the Latarjet group, 11 of 22 had %GBL >20% and 5 of 24 were contact athletes. Of 21 revision arthroscopy patients, 8 underwent concomitant remplissage. Eight of 21 patients in the revision arthroscopy group and 7 of 21 patients in the Latarjet group reported instability postoperatively. Three of 21 patients in the revision arthroscopy group and 2 of 21 patients in the Latarjet group reported full dislocations postoperatively. Zero patients in the revision arthroscopy group and 1 of 21 patients in the Latarjet group underwent reoperation. CONCLUSION: Our results suggest that both revision Latarjet and arthroscopic stabilization can be of benefit in select circumstances. However, in revision settings, postoperative instability symptoms are common with both procedures.

A single-institution analysis of factors affecting costs in the arthroscopic treatment of glenohumeral instability.

BACKGROUND: Although surgical shoulder stabilization is a substantial cost nationally within the United States, little information exists to analyze this cost. The purpose of this study was to identify factors associated with variation in direct costs with the arthroscopic treatment of glenohumeral instability. METHODS: This was a retrospective study of all patients who underwent arthroscopic treatment of glenohumeral instability between January 12, 2012 and July 11, 2017. Patient and procedure factors were collected. Direct perioperative costs were collected using a validated internal tool. Patient and procedure characteristics significantly associated with costs were identified using multivariate generalized linear models. RESULTS: The study included 302 patients, of whom 12% were undergoing revision and 32% were contact or collision athletes. Anterior instability was present in 73%, whereas 14% had posterior and 10% had multidirectional instability. Of the patients, 67% were recurrent dislocators and 33% were first-time dislocators or subluxators. Remplissage was performed in 13%; biceps tenodesis, 5%; and rotator cuff repair, 3%. An average of 4.0 ± 1.4 anchors were used. Of costs, 39% were operative facility utilization costs and 41% were implant costs. Factors associated with cost increase included an increased number of anchors (P < .0001), posterior vs. anterior instability (P = .001), recurrent instability vs. first-time dislocation (P = .025), remplissage (P = .006), rotator interval closure (P = .021), bicep tenodesis (P = .020), rotator cuff repair (P < .0001), an inpatient stay (P = .003), and repair of humeral avulsion of the glenohumeral ligaments (P = .012). CONCLUSION: Most perioperative costs associated with the arthroscopic treatment of glenohumeral instability are facility utilization and implant costs. Nonmodifiable factors associated with increased cost included posterior direction of instability and recurrent instability. Modifiable factors included additional procedures and inpatient stay.

The Muscle Cross-sectional Area on MRI of the Shoulder Can Predict Muscle Volume: An MRI Study in Cadavers.

BACKGROUND: Muscle volume is important in shoulder function. It can be used to estimate shoulder muscle balance in health, pathology, and repair and is indicative of strength based on muscle size. Although prior studies have shown that muscle area on two-dimensional (2-D) images correlates with three-dimensional (3-D) muscle volume, they have not provided equations to predict muscle volume from imaging nor validation of the measurements. QUESTIONS/PURPOSES: We wished to create an algorithm that quickly, accurately, and reliably estimates the volume of the shoulder muscles using cross-sectional area on MR images with low error. Specifically, we wished to (1) determine which MR imaging planes provide the highest correlation between shoulder muscle cross-sectional area and volume; (2) derive equations to predict muscle volume from cross-sectional area and validate their predictive capability; and (3) quantify the reliability of muscle cross-sectional area measurement. METHODS: Three-dimensional MRI was performed on 10 cadaver shoulders, with sample size chosen for comparison to prior studies of shoulder muscle volume and in consideration of the cost of comprehensive analysis, followed by dissection for muscle volume measurement via water displacement. From each MR series, 3-D models of the rotator cuff and deltoid muscles were generated, and 2-D slices of these muscle models were selected at defined anatomic landmarks. Linear regression equations were generated to predict muscle volume at the plane(s) with the highest correlation between volume and area and for planes identified in prior studies of muscle volume and area. Volume predictions from MR scans of six different cadaver shoulders were also made, after which they were dissected to quantify muscle volume. This validation population allowed the calculation of the predictive error compared with actual muscle volume. Finally, reliability of measuring muscle areas on MR images was calculated using intraclass correlation coefficients for inter-rater reliability, as measured between two observers at a single time point. RESULTS: The rotator cuff planes with the highest correlation between volume and area were the sum of the glenoid face and the midpoint of the scapula, and for the deltoid, it was the transverse plane at the top of the greater tuberosity. Water and digital muscle volumes were highly correlated (r ≥ 0.993, error < 4%), and muscle areas correlated highly with volumes (r ≥ 0.992, error < 2%). All correlations had p < 0.001. Muscle volume was predicted with low mean error (< 10%). All intraclass correlation coefficients were > 0.925, suggesting high inter-rater reliability in determining muscle areas from MR images. CONCLUSION: Deltoid and rotator cuff muscle cross-sectional areas can be reliably measured on MRI and predict muscle volumes with low error. CLINICAL RELEVANCE: Using simple linear equations, 2-D muscle area measurements from common clinical image analysis software can be used to estimate 3-D muscle volumes from MR image data. Future studies should determine if these muscle volume estimations can be used in the evaluation of patient function, changes in shoulder health, and in populations with muscle atrophy. Additionally, these muscle volume estimation techniques can be used as inputs to musculoskeletal models examining kinetics and kinematics of humans that rely on subject-specific muscle architecture.

Does Bone Loss Imaging Modality, Measurement Methodology, and Interobserver Reliability Alter Treatment in Glenohumeral Instability?

PURPOSE: To determine, in the context of measuring bone loss in shoulder instability, whether measurement differences between magnetic resonance imaging (MRI) and computed tomography (CT), linear-based and area-based methods, and observers altered the proposed treatment when a standardized algorithm was applied. METHODS: This was a retrospective, comparative imaging study of preoperative patients with anterior shoulder instability with both an MRI and CT scan within 1 year of one another. On parasagittal images reoriented en face to the glenoid, 2 attending orthopaedic surgeons measured glenoid width, glenoid area, glenoid defect width, and glenoid defect area. On axial images maximal Hill-Sachs width was measured. From these, linear percent glenoid bone loss (%GBL) and area %GBL were calculated, and on-versus off-track was determined. With these results, a recommended treatment was determined by applying a standardized algorithm, in which the Latarjet procedure was selected for %GBL >20%, arthroscopic labral repair and remplissage for off-track lesions with %GBL <20%, and arthroscopic labral repair on-track shoulders with %GBL <20%. RESULTS: In total, 53 patients with mean ± standard deviation 45 ± 83 days between scans were include with a CT linear %GBL of 23.5 ± 9.6% (range 0%-47%). CT lead to larger measurements of %GBL than MRI (linear P = .008, area P = .003), and fewer shoulders being considered on-track (33.0% vs 40.5%), which would alter treatment in 25% to 34%. Linear measurements produced larger values for %GBL (CT, P < .001; MRI, P < .001), which would alter treatment in 25%. For %GBL, inter-rater reliability was good, with intraclass correlation coefficients varying from 0.727 to 0.832 and Kappa varying from 0.57 to 0.62, but these inter-rater differences would alter treatment in 31%. CONCLUSIONS: The significant differences in bone loss measurement between imaging modality, measurement method, and observers may lead to differences in treatment in up to 34% of cases. Linear CT measurements resulted in the most aggressive treatment recommendations. LEVEL OF EVIDENCE: Retrospective Comparative Study: Diagnostic, Level III.

A Cost-Minimization Analysis of Intraoperative Costs in Arthroscopic Bankart Repair, Open Latarjet, and Distal Tibial Allograft.

BACKGROUND: The optimal surgical treatment of anterior shoulder instability remains controversial. HYPOTHESIS: (1) Implants and facility-related costs are the primary drivers of variation in direct costs between arthroscopic Bankart and Latarjet procedures, and (2) distal tibial allograft (DTA) is more costly than Latarjet as a function of the graft expense. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Intraoperative cost data were derived for all arthroscopic anterior stabilizations and Latarjet and DTA procedures performed at a single academic institution from January 2012 to September 2017. Cost comparisons were made between those undergoing arthroscopic stabilization and Latarjet and between Latarjet and DTA. Multivariate regressions were performed to determine the difference in direct costs accounting for various patient- and surgery-related factors. RESULTS: A total of 87 arthroscopic stabilizations, 44 Latarjet procedures, and 5 DTA procedures were performed during the study period. Arthroscopic Bankart repair was found to be 17% more costly than Latarjet, with suture anchor implant cost being the primary driver of cost. DTA was 2.9-fold more costly than Latarjet, with greater costs across all domains. Multivariate analysis also found the number of prior arthroscopic procedures performed (P = .007) and whether the procedure was performed in an ambulatory or inpatient setting (P < .0001) to be significantly associated with higher direct costs. CONCLUSION: Latarjet is less costly than arthroscopic Bankart repair, largely because of implant cost. Value-driven strategies to narrow the cost differential could focus on performing these procedures in an outpatient setting in addition to reducing overall implant cost for arthroscopic procedures. Perceived potential benefits of DTA over Latarjet may be outweighed by higher costs.