Automated Nerve Monitoring in Shoulder Arthroplasty: A Prospective Randomized Controlled Study.

BACKGROUND: Evoked potential monitoring is believed to prevent neurologic injury in various surgical settings; however, its clinical effect has not been scrutinized. It was hypothesized that an automated nerve monitor can minimize intraoperative nerve injury and thereby improve clinical outcomes in patients undergoing shoulder arthroplasty. METHODS: A prospective, blinded, parallel group, superiority design, single-center, randomized controlled study was conducted. Study participants were equally randomized into either the automated nerve-monitored or the blinded monitored groups. The primary outcome was intraoperative nerve injury burden as assessed by the cumulative duration of nerve alerts. Secondary outcomes were neurologic deficits and functional scores of the operative arm, and the quality of life index (Euro Quality of life-5 domain-5 level score) at postoperative weeks 2, 6, and 12. RESULTS: From September 2018 to July 2019, 213 patients were screened, of whom 200 were randomized. There was no statistically significant difference in the duration of nerve alerts between the automated nerve-monitored and control groups (median [25th, 75th interquartile range]: 1 [0, 18] and 5 [0, 26.5]; Hodges-Lehman difference [95% CI]: 0 [0 to 1] min; P = 0.526). There were no statistically significant differences in secondary outcomes between groups. However, in the ancillary analysis, there were reductions in neurologic deficits and improvements in quality of life index occurring in both groups over the course of the study period. CONCLUSIONS: Protection from nerve injury is a shared responsibility between surgeons and anesthesiologists. Although a progressive improvement of clinical outcomes were observed over the course of the study in both groups as a consequence of the real-time feedback provided by the automated nerve monitor, this trial did not demonstrate that automated nerve monitoring by itself changes important clinical outcomes compared with no monitoring.

Cutibacterium acnes and the shoulder microbiome.

BACKGROUND: Advances in DNA sequencing technologies have made it possible to detect microbial genome sequences (microbiomes) within tissues once thought to be sterile. We used this approach to gain insights into the likely sources of Cutibacterium acnes (formerly Propionibacterium acnes) infections within the shoulder. METHODS: Tissue samples were collected from the skin, subcutaneous fat, anterior supraspinatus tendon, middle glenohumeral ligament, and humeral head cartilage of 23 patients (14 male and 9 female patients) during primary arthroplasty surgery. Total DNA was extracted and microbial 16S ribosomal RNA sequencing was performed using an Illumina MiSeq system. Data analysis software was used to generate operational taxonomic units for quantitative and statistical analyses. RESULTS: After stringent removal of contamination, genomic DNA from various Acinetobacter species and from the Oxalobacteraceae family was identified in 74% of rotator cuff tendon tissue samples. C acnes DNA was detected in the skin of 1 male patient but not in any other shoulder tissues. CONCLUSION: Our findings indicate the presence of a low-abundance microbiome in the rotator cuff and, potentially, in other shoulder tissues. The absence of C acnes DNA in all shoulder tissues assessed other than the skin is consistent with the hypothesis that C acnes infections are derived from skin contamination during surgery and not from opportunistic expansion of a resident C acnes population in the shoulder joint.

A randomized clinical trial to compare the effectiveness of rotator cuff repair with or without augmentation using porcine small intestine submucosa for patients with moderate to large rotator cuff tears: a pilot study.

BACKGROUND: The rate of rotator cuff repair failure is between 13% and 67%. Porcine small intestine submucosa (SIS) may be suitable to augment the repair. METHODS: There were 62 patients with moderate and large cuff tears randomized to repair alone (control) or augmentation with SIS (Restore Orthobiologic Implant; DePuy, Warsaw, IN, USA). Primary outcome was repair failure using magnetic resonance arthrography. Randomization occurred on completion of the repair. Patients and assessors were blind to group. Assessments occurred preoperatively and postoperatively at 2 and 6 weeks and 3, 6, 12, and 24 months. RESULTS: There were 62 patients randomized (34 SIS, 28 control). Patient demographics, rotator cuff tear characteristics, and repair details were similar between groups. At 1 year, risk of failure was 52.9% (18/34) in the SIS group and 65.4% (17/26) in the control group for a risk difference of 12% (80% confidence interval, -7% to 32%) or relative risk of 0.81 (95% confidence interval, 0.53-1.24, P = .33) in favor of SIS. At 1 and 2 years, the mean difference between groups for patient-reported outcomes was small and consistent with chance but did not exclude the possibility of a clinically important difference. There was no statistically significant difference (P = .50) between the SIS group (59.6 ± 38.9; range, 3-112) and the control group (52.7 ± 38.6; range, 5-112) in number of days to being narcotic and pain free (<20 mm on a 100-mm visual analog scale). CONCLUSION: We found no evidence that SIS-augmented rotator cuff repair provides superior outcomes in patients with moderate rotator cuff tears.

Does bony increased-offset reverse shoulder arthroplasty decrease scapular notching?

BACKGROUND: The purpose of this cohort study was to compare scapular notching rates, range of motion, and functional outcomes between patients who underwent a standard Grammont-style reverse shoulder arthroplasty (RSA) and patients who underwent bony increased-offset reverse shoulder arthroplasty (BIO-RSA) at a minimum of 2 years' follow-up. We hypothesized that the BIO-RSA cohort would have lower notching rates and improved rotational range of motion; however, validated outcome scores between cohorts would be no different. METHODS: A comparative cohort study was designed after a sample size calculation. A total of 40 patients were studied with 20 in each cohort (RSA vs BIO-RSA). All patients underwent an interview and physical examination. Outcomes included range of motion; shoulder strength; Disabilities of the Arm, Shoulder and Hand (DASH) score; American Shoulder and Elbow Surgeons score; Simple Shoulder Test score; Constant score; and Global Rating of Change scale score. Radiographs were obtained for all patients and examined for scapular notching. RESULTS: When we compared demographic characteristics between the standard RSA and BIO-RSA cohorts, including age, sex, and follow-up duration, there were no significant differences between groups (P > .05). In addition, there were no significant differences between cohorts when we compared forward elevation (P = .418); external rotation (P = .999); internal rotation (P = .071); strength (P > .376); Disabilities of the Arm, Shoulder and Hand score (P = .229); American Shoulder and Elbow Surgeons score (P = .579); Simple Shoulder Test score (P = .522); Constant score (P = .917); or Global Rating of Change scale score (P = .167). The frequency of scapular notching, however, was significantly higher (P = .022) in the RSA cohort than in the BIO-RSA cohort: 75% versus 40%. CONCLUSIONS: Although the scapular notching rate was significantly higher in the standard RSA group, no other outcome measures were statistically different, including range of motion, strength, and validated outcome scores.

IGF2 expression and ß-catenin levels are increased in Frozen Shoulder Syndrome.

PURPOSE: Frozen Shoulder Syndrome is a fibrosis of the shoulder joint capsule that is clinically associated with Dupuytren's disease, a fibrosis of the palmar fascia. Little is known about any commonalities in the pathophysiology of these connective tissue fibroses. ß-catenin, a protein that transactivates gene expression, and levels of IGF2 mRNA, encoding insulin-like growth factor-II, are elevated in Dupuytren's disease. The aim of this study was to determine if correlating changes in ß-catenin levels and IGF2 expression are evident in Frozen Shoulder Syndrome. METHODS: Tissue from patients with Frozen Shoulder Syndrome and rotator cuff tear were obtained during shoulder arthroscopies. Total protein extracts were prepared from tissue aliquots and ß-catenin immunoreactivity was assessed by Western immunoblotting. In parallel, primary fibroblasts were derived from these tissues and assessed for IGF2 expression by quantitative PCR. RESULTS: ß-catenin levels were significantly increased in Frozen Shoulder Syndrome relative to rotator cuff tear when assessed by Western immunoblotting analyses. IGF2 mRNA levels were significantly increased in primary fibroblasts derived from frozen shoulder syndrome tissues relative to fibroblasts derived from rotator cuff tissues. CONCLUSIONS: As in Dupuytren's disease, ß-catenin levels and IGF2 expression are elevated in Frozen Shoulder Syndrome. These findings support the hypothesis that these connective tissue fibroses share a common pathophysiology.

A randomized controlled trial of nonoperative treatment versus open reduction and internal fixation for stable, displaced, partial articular fractures of the radial head: the RAMBO trial.

BACKGROUND: The choice between operative or nonoperative treatment is questioned for partial articular fractures of the radial head that have at least 2 millimeters of articular step-off on at least one radiograph (defined as displaced), but less than 2 millimeter of gap between the fragments (defined as stable) and that are not associated with an elbow dislocation, interosseous ligament injury, or other fractures. These kinds of fractures are often classified as Mason type-2 fractures. Retrospective comparative studies suggest that operative treatment might be better than nonoperative treatment, but the long-term results of nonoperative treatment are very good. Most experts agree that problems like reduced range of motion, painful crepitation, nonunion or bony ankylosis are infrequent with both nonoperative and operative treatment of an isolated displaced partial articular fracture of the radial head, but determining which patients will have problems is difficult. A prospective, randomized comparison would help minimize bias and determine the balance between operative and nonoperative risks and benefits. METHODS/DESIGN: The RAMBO trial (Radial Head - Amsterdam - Amphia - Boston - Others) is an international prospective, randomized, multicenter trial. The primary objective of this study is to compare patient related outcome defined by the 'Disabilities of Arm, Shoulder and Hand (DASH) score' twelve months after injury between operative and nonoperative treated patients. Adult patients with partial articular fractures of the radial head that comprise at least 1/3rd of the articular surface, have ≥ 2 millimeters of articular step-off but less than 2 millimeter of gap between the fragments will be enrolled. Secondary outcome measures will be the Mayo Elbow Performance Index (MEPI), the Oxford Elbow Score (OES), pain intensity through the 'Numeric Rating Scale', range of motion (flexion arc and rotational arc), radiographic appearance of the fracture (heterotopic ossification, radiocapitellar and ulnohumeral arthrosis, fracture healing, and signs of implant loosening or breakage) and adverse events (infection, nerve injury, secondary interventions) after one year. DISCUSSION: The successful completion of this trial will provide evidence on the best treatment for stable, displaced, partial articular fractures of the radial head. TRIAL REGISTRATION: The trial is registered at the Dutch Trial Register: NTR3413.

Assessing changes in regional cerebral hemodynamics in adults with a high-density full-head coverage time-resolved near-infrared spectroscopy device.

Significance: Cerebral oximeters have the potential to detect abnormal cerebral blood oxygenation to allow for early intervention. However, current commercial systems have two major limitations: (1) spatial coverage of only the frontal region, assuming that surgery-related hemodynamic effects are global and (2) susceptibility to extracerebral signal contamination inherent to continuous-wave near-infrared spectroscopy (NIRS). Aim: This work aimed to assess the feasibility of a high-density, time-resolved (tr) NIRS device (Kernel Flow) to monitor regional oxygenation changes across the cerebral cortex during surgery. Approach: The Flow system was assessed using two protocols. First, digital carotid compression was applied to healthy volunteers to cause a rapid oxygenation decrease across the ipsilateral hemisphere without affecting the contralateral side. Next, the system was used on patients undergoing shoulder surgery to provide continuous monitoring of cerebral oxygenation. In both protocols, the improved depth sensitivity of trNIRS was investigated by applying moment analysis. A dynamic wavelet filtering approach was also developed to remove observed temperature-induced signal drifts. Results: In the first protocol (28±5 years; five females, five males), hair significantly impacted regional sensitivity; however, the enhanced depth sensitivity of trNIRS was able to separate brain and scalp responses in the frontal region. Regional sensitivity was improved in the clinical study given the age-related reduction in hair density of the patients (65±15 years; 14 females, 13 males). In five patients who received phenylephrine to treat hypotension, different scalp and brain oxygenation responses were apparent, although no regional differences were observed. Conclusions: The Kernel Flow has promise as an intraoperative neuromonitoring device. Although regional sensitivity was affected by hair color and density, enhanced depth sensitivity of trNIRS was able to resolve differences in scalp and brain oxygenation responses in both protocols.

Balancing clinician and patient priorities for total shoulder replacement preoperative education programs.

OBJECTIVE: To investigate patient and clinician preferences regarding a preoperative educational program for patients undergoing shoulder replacement surgery. METHODS: This study used a cross-sectional survey of patients awaiting shoulder replacement surgery and clinicians. The survey was comprised of 41 questions for patients and clinicians, regarding preferences for receiving information, content preferences and device preferences. Descriptive statistics were reported for survey questions. RESULTS: 180 patients and 175 clinicians completed the survey. Patients and clinicians' top choices for ways to receive information were: in-person, website and booklets, with use of CD/DVD being extremely unlikely. Patients and clinicians had different preferences regarding content choices. Patients rated the following content topics as important to include in a program: including other patient's previous experiences with this surgery (83 % patients; 40 % clinicians), information for caregivers (84 % patients; 65 % clinicians), expectations for hospital stay (89 % patients; 57 % clinicians), process of anesthesia (87 % patients; 51 % clinicians), and how the surgery is performed (94 % patients; 60 % clinicians). CONCLUSIONS: Clinicians and patients have differing priorities and perspectives on the content and delivery of preoperative education programs, however, therapeutic goals and accessibility should be considered when designing programs. PRACTICE IMPLICATIONS: Creating education programs should include the lens of both clinicians and patients.

Assessing Appropriateness for Shoulder Arthroplasty Using a Shared Decision-Making Process.

Purpose: The primary purpose of this study was to validate an appropriateness decision-aid tool as a part of engaging patients with glenohumeral arthritis in their surgical management. The associations between the final decision to have surgery and patient characteristics were examined. Materials and Methods: This was an observational study. The demographics, overall health, patient-specific risk profile, expectations, and health-related quality of life were documented. Visual analog scale and the American Shoulder & Elbow Surgeon (ASES) measured pain and functional disability, respectively. Clinical and imaging examination documented clinical findings and extent of degenerative arthritis and cuff tear arthropathy. Appropriateness for arthroplasty surgery was documented by a 5-item Likert response survey and the final decision was documented as ready, not-ready, and would like to further discuss. Results: Eighty patients, 38 women (47.5%), mean age: 72(8) participated in the study. The appropriateness decision aid showed excellent discriminate validity (area under the receiver operating characteristic curve value of 0.93) in differentiating between patients who were "ready" and those who were "not-ready" to have surgery. Gender (P = 0.037), overall health (P = .024), strength in external rotation (P = .002), pain severity (P = .001), ASES score (P < .0001), and expectations (P = .024) were contributing factors to the decision to have surgery. Imaging findings did not play a significant role in the final decision to have surgery. Conclusions: A 5-item tool showed excellent validity in differentiating patients who were ready to have surgery versus those who were not. Patient's gender, expectations, strength, and self-reported outcomes were important factors in reaching the final decision.

Cemented versus uncemented fixation of humeral components in total shoulder arthroplasty for osteoarthritis of the shoulder: a prospective, randomized, double-blind clinical trial-A JOINTs Canada Project.

BACKGROUND: Although cemented humeral fixation is recognized as the standard of care in total shoulder arthroplasty (TSA), uncemented fixation has the potential to provide stable fixation, decrease operative time, and simplify potential revision procedures. This prospective, randomized, double-blind clinical trial compared cemented and uncemented humeral fixation in TSA for primary shoulder osteoarthritis. METHODS: Patients with primary shoulder osteoarthritis requiring replacement were screened for eligibility. After providing informed consent, subjects received baseline clinical and radiologic assessments, computed tomography scans, and standardized TSA. After glenoid component insertion, patients were randomized to either a cemented or uncemented humeral component. The primary outcome was the WOOS (Western Ontario Arthritis of the Shoulder Index) score at 2 years. Other outcomes included the Short Form 12 score, American Shoulder and Elbow Surgeons score, McMaster-Toronto Arthritis Patient Preference Disability Questionnaire, operative time, complications, and revisions. Patients were assessed by a blinded evaluator at 2 and 6 weeks and 3, 6, 12, 18, and 24 months postoperatively. RESULTS: In total, 161 patients consented to be included and were randomized: 80 in the cemented group and 81 in the uncemented group. There were no significant differences in demographics or baseline evaluations between groups, except for gender. The 12-, 18-, and 24-month WOOS scores showed a significant difference in favor of the cemented group. The cemented group also had better strength and forward flexion. As expected, the operative time was significantly less for the uncemented group. CONCLUSIONS: These findings provide level I evidence that cemented fixation of the humeral component provides better quality of life, strength, and range of motion than uncemented fixation.

Surgical Management and Rehabilitation of an Olecranon Fracture in a Patient with Thrombocytopenia-Absent Radii: A Case Report.

CASE: A 29-year-old right-hand dominant woman with thrombocytopenia-absent radii syndrome was surgically treated for a right olecranon fracture. Given her forearm deformity and short lever arm, a custom-modified corrective elbow flexion splint was used during rehabilitation. Radiographic union was achieved. Although functional outcome scores were similar to the ones previously reported in the general population, the patient had persistent extension contracture. CONCLUSION: Despite good functional outcomes, the patient had reduced range of motion. With severe limb deformity, the greatest challenge is to provide optimal rehabilitation protocols and individualized tools.

Maximizing Muscle Function in Cuff-Deficient Shoulders: A Rehabilitation Proposal for Reverse Arthroplasty.

PURPOSE: The purpose of this review is to describe the role of altered joint biomechanics in reverse shoulder arthroplasty and to propose a rehabilitation protocol for a cuff-deficient glenohumeral joint based on the current evidence.Methods and Materials: The proposed rehabilitation incorporates the principles of pertinent muscle loading while considering risk factors and surgical complications. RESULTS: In light of altered function of shoulder muscles in reverse arthroplasty, scapular plane abduction should be more often utilized as it better activates deltoid, teres minor, upper trapezius, and serratus anterior. Given the absence of supraspinatus and infraspinatus and reduction of external rotation moment arm of the deltoid in reverse arthroplasty, significant recovery of external rotation may not occur, although an intact teres minor may assist external rotation in the elevated position. CONCLUSION: Improving the efficiency of deltoid function before and after reverse shoulder arthroplasty is a key factor in the rehabilitation of the cuff deficient shoulders. Performing exercises in scapular plane and higher abduction angles activates deltoid and other important muscles more efficiently and optimizes surgical outcomes.

Arthroscopic Versus Mini-open Rotator Cuff Repair: A Randomized Trial and Meta-analysis.

BACKGROUND: Patients with complete rotator cuff tears who fail a course of nonoperative therapy can benefit from surgical repair. PURPOSE: This randomized trial compared mini-open (MO) versus all-arthroscopic (AA) rotator cuff repair. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: Patients with rotator cuff tears were randomized to undergo MO or AA repair at 9 centers by 23 surgeons. The primary outcome (Western Ontario Rotator Cuff Index [WORC]) and secondary outcomes (American Shoulder and Elbow Surgeons [ASES] score, Shoulder Pain and Disability Index [SPADI] pain subscale, 12-Item Short Form Health Survey [SF-12], reported medication use, adverse events), as well as measurements of range of motion and strength, were collected at 1 month before surgery; at 2 and 6 weeks postoperatively; and at 3, 6, 12, 18, and 24 months postoperatively. A blinded radiologist evaluated rotator cuff integrity on magnetic resonance imaging (MRI) at baseline and 1 year. Intention-to-treat analysis of covariance with the preoperative WORC score, age, and tear size as covariates assessed continuous outcomes. Sex differences were assessed. A meta-analysis synthesized the primary outcome between MO and AA repair with previous trials. RESULTS: From 954 patients screened, 411 were ineligible (276 because of recovery with physical therapy), 449 were screened at surgery (175 ineligible), and 274 completed follow-up (138 MO and 136 AA). The AA and MO groups were similar before surgery. WORC scores improved from 40 preoperatively to 89 (AA) and 93 (MO) at 2 years, for an adjusted mean difference of 3.4 (95% CI, -0.4 to 7.2). There were no statistically significant differences between the AA and MO groups at any time point. All secondary patient-reported outcomes were not significantly different between the MO and AA groups, except the 2-year SPADI pain score (8 vs 12, respectively; P = .02). A similar recovery in range of motion and strength occurred in both groups over time. MRI indicated minimal improvement in muscle relative to fat (AA: n = 3; MO: n = 2), with most worsening (AA: n = 25; MO: n = 24) or remaining unchanged (AA: n = 70; MO: n = 70). Opioid use was significantly reduced after surgery (from 21% to 5%). The meta-analysis indicated no significant standardized mean difference between groups in the primary outcome across all pooled studies (standardized mean difference, -0.06 [95% CI, -0.34 to 0.22]). CONCLUSION: Both AA and MO rotator cuff repair provide large clinical benefits, with few adverse events. There is strong evidence of equivalent clinical improvements. TRIAL REGISTRATION: NCT00128076.

The incidence of early metallic suture anchor pullout after arthroscopic rotator cuff repair.

PURPOSE: The purpose of this study was to identify the incidence of metallic suture anchor pullout after arthroscopic rotator cuff repair and determine the impact of tear size on the risk of pullout. METHODS: A retrospective review of 269 patients (550 metallic suture anchors) who underwent arthroscopic rotator cuff repair between January 2006 and January 2009 was conducted. Inclusion criteria included patients aged 18 years or older, a minimum of 6 weeks' radiographic follow-up, and the use of 1 or more metallic suture anchors for partial or complete rotator cuff repair. The mean age of the cohort at the time of surgery was 55 years (range, 29 to 86 years), and there were 189 men and 80 women. RESULTS: Early anchor pullout occurred in 6 patients (9 anchors). The overall incidence of early metallic suture anchor pullout in this cohort was 2.4% (95% confidence interval, 0.5% to 4.3%). The incidence in rotator cuff tears less than or equal to 3 cm was 0.5%, and the incidence in tears greater than 3 cm was 11%. Patients undergoing arthroscopic rotator cuff repair of a tear greater than 3 cm in size were at a significantly higher risk of having early metallic suture anchor pullout than patients undergoing repair of a smaller tear (relative risk, 22; P = .001). Among the 61 patients undergoing arthroscopic subscapularis repair, no suture anchor failures were observed at the lesser tuberosity. Of the 9 anchors that failed, 8 (89%) pulled out of the posterior aspect of the greater tuberosity. CONCLUSIONS: There is a minimal risk of suture anchor pullout in small- to medium-sized tears; however, this risk increases with larger tear sizes. We recommend routine radiographic follow-up after use of metallic anchors to ensure identification of early failure by anchor pullout. LEVEL OF EVIDENCE: Level III, prognostic case series.

The simple shoulder test is responsive in assessing change following shoulder arthroplasty.

STUDY DESIGN: Prospective cohort study with repeated measures. OBJECTIVE: To establish the responsiveness of the Simple Shoulder Test (SST) in comparison to other commonly used clinical outcomes in patients undergoing shoulder arthroplasty. BACKGROUND: Responsiveness statistics are a useful means to compare different outcomes in terms of their ability to detect clinical change. While the responsiveness of the SST has been established for rotator cuff repair, it has not been determined for patients undergoing arthroplasty. METHODS: Patients undergoing shoulder arthroplasty (n=120) were evaluated prior to surgery and 6 months after. The evaluation included the SST, Disabilities of the Arm, Shoulder and Hand questionnaire, range of motion, and isometric strength. Responsiveness to change was assessed using standardized response mean (SRM), while longitudinal construct validity was evaluated using Pearson correlation. Receiver operating characteristics curves were plotted to determine clinically important difference of SST. RESULTS: The SST and Disabilities of the Arm, Shoulder and Hand questionnaire were highly responsive (SRM, >1.70) for this population. For the assessment of impairment, range of motion (SRM, 0.64-1.03) was moderately to highly responsive, while isometric strength was minimally to moderately responsive (SRM, 0.32-0.69). The clinically important difference of the SST was established at 3.0 SST points. Pearson correlations indicated moderate associations between the change scores of the SST and the Disabilities of the Arm, Shoulder and Hand questionnaire (r=0.49). CONCLUSIONS: The SST has been previously shown to be valid and highly reliable. The present results show that the SST is also responsive following shoulder arthroplasty and that it has a clinically important difference of 3.0 SST points. This should provide confidence to clinicians who wish to use a brief shoulder-specific measure in their practice.

Substantial clinical benefit, responsiveness, and sensitivity to change of three common outcome measures following shoulder arthroplasty.

OBJECTIVES: It is important for clinicians involved in the care of patients with advanced glenohumeral osteoarthritis to determine clinically significant change when using outcome measures. There is little information on the amount of substantial clinical benefit in shoulder outcomes after shoulder arthroplasty. The purpose of this study was twofold: (1) to quantify substantial clinical benefit for the American Shoulder and Elbow Surgery score, the Constant Murley Score, and the Western Ontario Osteoarthritis of the Shoulder index and (2) to provide estimates of responsiveness and sensitivity to change for these measures following shoulder arthroplasty. METHODS: The study involved a secondary analysis of previously collected data. The substantial clinical benefit and responsiveness of the measures were calculated based on external anchors related to change in pain, range of motion, and ability to carry out activities of daily living. The areas under curve and standardized response mean represented responsiveness and sensitivity to change. RESULTS: The data of 159 and 131 patients with complete follow-up at 6 months and 2 years were reviewed. The amount of substantial clinical benefit was dependent on the outcome measure and the external anchor and increased for all measures from 6 months to 2 years. Responsiveness was high (areas under curve > 0.80) at 6 months and further improved at 2 years (areas under curve > 0.88). The standardized response mean values of both time points were over 2.00, indicating high effect sizes. The standardized response means of the Constant Murley Score were statistically significantly higher than the standardized response means of the American Shoulder and Elbow Surgery and Western Ontario Osteoarthritis of the Shoulder. CONCLUSION: Amount of substantial clinical improvement in pain, range of motion, and activities of daily living following shoulder arthroplasty depends on the type of outcome measure used. All three measures, the American Shoulder and Elbow Surgery, absolute and relative Constant Murley Score, and Western Ontario Osteoarthritis of the Shoulder, demonstrated good to excellent accuracy and optimal standardized response means. LEVEL OF EVIDENCE: Level III, Retrospective Cohort study.

Improved accuracy of computer assisted glenoid implantation in total shoulder arthroplasty: an in-vitro randomized controlled trial.

BACKGROUND: Glenoid replacement is challenging due to the difficult joint exposure and visualization of anatomical reference landmarks. Improper positioning of the glenoid component or inadequate correction of the retroversion using currently available instrumentation may lead to early failure. The objective of this study was to evaluate a computer-assisted technique to achieve a more accurate placement of the glenoid component compared to traditional techniques. METHODS: Sixteen paired cadaveric shoulders were randomized to either traditional or computer-assisted glenoid implantation. Preoperative planning consisting of CT scanning with 3-dimensional image modeling of the shoulder specimens and intraoperative tracking with real-time feedback provided to the surgeon was employed in the computer-assisted group. A validated, previously published, standardized protocol for tracking the orientation of the glenoid in space using 3 glenoid surface landmarks was employed. All phases of glenoid implantation (initial guide pin insertion, reaming, drilling of the peg holes, and final component implantation) were tracked and recorded by the computer. A post-implantation CT scan was performed in both groups to compare how accurately the implants were placed. RESULTS: The computer-assisted technique was more accurate in achieving the correct version during all phases of glenoid implantation and as measured on the post-implantation CT scan (P < .05). The largest errors with traditional glenoid implantation were observed during drilling and, more so, during reaming. The trend was to overly retrovert the glenoid. CONCLUSIONS: Computer assisted navigation results in a more accurate glenoid component placement relative to traditional techniques. LEVEL OF EVIDENCE: Basic Science Study.

A Pilot Study of a Novel Automated Somatosensory Evoked Potential (SSEP) Monitoring Device for Detection and Prevention of Intraoperative Peripheral Nerve Injury in Total Shoulder Arthroplasty Surgery.

INTRODUCTION: Peripheral nerve injury is a potentially devastating complication after total shoulder arthroplasty (TSA) surgery. This pilot study aimed to assess the feasibility of using an automated somatosensory evoked potential (SSEP) device to provide a timely alert/intervention to minimize intraoperative nerve insults during TSA surgery. METHODS: A prospective, single-arm, observational study was conducted in a single university hospital. The attending anesthesiologist monitored the study participants using the EPAD automated SSEP device and an intervention was made if there was an alert during TSA surgery. The median, radial, and ulnar nerve SSEP on the operative arm, as well as the median nerve SSEP of the nonoperative arm were monitored for each patient. All patients were evaluated for postoperative neurological deficits 6 weeks postoperatively. RESULTS: In total, 21 patients were consented and were successfully monitored. In total, 4 (19%) patients developed intraoperative abnormal SSEP signal changes in the operative arm, in which 3 were reversible and 1 was irreversible till the end of surgery. Median and radial nerves were mostly involved (3/4 patients). The mean cumulative duration of nerve insult (abnormal SSEP) was 21.7±26.2 minutes. Univariate analysis did not identify predictor of intraoperative nerve insults. No patients demonstrated postoperative peripheral neuropathy at 6 weeks. CONCLUSIONS: A high incidence (19%) of intraoperative nerve insult was observed in this study demonstrating the feasibility of using an automated SSEP device to provide a timely alert and enable an intervention in order to minimize peripheral nerve injury during TSA. Further randomized studies are warranted.