Wright, Jonathan O

Background: When missing data are present in clinical outcomes studies, complete-case analysis (CCA) is often performed, whereby patients with missing data are excluded. While simple, CCA analysis may impart selection bias and reduce statistical power, leading to erroneous statistical results in some cases. However, there exist more rigorous statistical approaches, such as single and multiple imputation, which approximate the associations that would have been present in a full dataset and preserve the study’s power. The purpose of this study is to evaluate how statistical results differ when performed after CCA analysis versus imputation methods. Methods: This simulation study analyzed a sample dataset consisting of 2204 shoulders, with complete datapoints from a larger multicenter total shoulder arthroplasty database. From the sampled dataset of demographics, surgical characteristics, and clinical outcomes, we created five test datasets, ranging from 100 to 2000 shoulders, and simulated 10–50% missingness in the postoperative American Shoulder and Elbow Surgeons (ASES) score and range of motion in four planes in missing completely at random (MCAR), missing at random (MAR), and not missing at random (NMAR) patterns. Missingness in outcomes was remedied using CCA, three single imputation techniques, and two multiple imputation techniques. The imputation performance was evaluated relative to the native complete dataset using the root mean squared error (RMSE) and the mean absolute percentage error (MAPE). We also compared the mean and standard deviation (SD) of the postoperative ASES score and the results of multivariable linear and logistic regression to understand the effects of imputation on the study results. Results: The average overall RMSE and MAPE were similar for MCAR (22.6 and 27.2%) and MAR (19.2 and 17.7%) missingness patterns, but were substantially poorer for NMAR (37.5 and 79.2%); the sample size and the percentage of data missingness minimally affected RMSE and MAPE. Aggregated mean postoperative ASES scores were within 5% of the true value when missing data were remedied with CCA, and all candidate imputation methods for nearly all ranges of sample size and data missingness when data were MCAR or MAR, but not when data were NMAR. When data were MAR, CCA resulted in overestimates of the SD. When data were MCAR or MAR, the accuracy of the regression estimate (β or OR) and its corresponding 95% CI varied substantially based on the sample size and proportion of missing data for multivariable linear regression, but not logistic regression. When data were MAR, the width of the 95% CI was up to 300% larger when CCA was used, whereas most imputation methods maintained the width of the 95% CI within 50% of the true value. Single imputation with k-nearest neighbor (kNN) method and multiple imputation with predictive mean matching (MICE-PMM) best-reproduced point estimates and intervariable relationships resembling the native dataset. Availability of correlated outcome scores improved the RMSE, MAPE, accuracy of the mean postoperative ASES score, and multivariable linear regression model estimates. Conclusions: Complete-case analysis can introduce selection bias when data are MAR, and it results in loss of statistical power, resulting in loss of precision (i.e., expansion of the 95% CI) and predisposition to false-negative findings. Our data demonstrate that imputation can reliably reproduce missing clinical data and generate accurate population estimates that closely resemble results derived from native primary shoulder arthroplasty datasets (i.e., prior to simulated data missingness). Further study of the use of imputation in clinical database research is critical, as the use of CCA may lead to different conclusions in comparison to more rigorous imputation approaches.

Background: Reverse shoulder arthroplasty (RSA) is increasingly used in the treatment of displaced proximal humerus fractures (PHFs) with reliable clinical improvement. However, the preferred techniques for humeral stem fixation are varied and may be influenced by patient and injury characteristics, including bone quality and fracture pattern. This systematic review and meta-analysis sought to determine the effect of humeral component cementing and bone grafting on tuberosity healing rates and functional outcomes after RSA for PHFs. Methods: A systematic review was performed per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed/MEDLINE, EMBASE, Web of Science, and Cochrane were queried for clinical studies on RSA performed for PHFs that reported on the use of cemented humeral stems and autograft bone. The primary outcome was the rate of greater tuberosity healing between the various techniques. Secondarily, the authors compared clinical outcomes including postoperative external rotation, forward elevation, abduction, Constant score, and the incidence of complications and revision surgery. Outcomes were compared based on the use of an uncemented press-fit stem, a fully cemented stem without bone graft, or a partially cemented stem with humeral head autograft (i.e., black and tan technique). Results: Forty-eight studies reporting on 1,797 RSAs were included (mean patient age, 75 years; follow-up, 34 months; 81% female). Tuberosity healing was highest in the uncemented cohort, then the black and tan cohort, and lowest in the cemented cohort (80% vs. 70% vs. 61%, p = 0.006). No significant differences in postoperative range of motion, Constant score, complication rates, or revision rates were found. Conclusion: Uncemented fixation with a press-fit stem was associated with superior greater tuberosity healing rates; however, functional outcomes and complications did not differ among techniques. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Background This study sought to characterize the tipping point values (the functional scores that patients deem dysfunctional enough to warrant surgery) for patients undergoing first revision reverse total shoulder arthroplasty (rTSA). Methods This study was a retrospective review of a prospectively collected single-institution database of patients undergoing first revision rTSA between August 2015 and December 2019. Tipping point evaluation utilized preoperative scores including the American Shoulder and Elbow Surgeons (ASES), raw and normalized Constant, Shoulder Pain and Disability Index (SPADI), Simple Shoulder Test (SST), and University of California-Los Angeles (UCLA) scores, and active range of motion including abduction, forward elevation (FE), external rotation (ER), and internal rotation score (IR) prior to elective revision rTSA. Results We included 125 revision rTSAs. Tipping points were 37.6 ASES score, 30.5 raw Constant score, 35.5 normalized Constant score, 68.1 SPADI, 3.7 SST, 13.2 UCLA score, 64° abduction, 69° FE, 23° ER, and 3.1 IR. Higher SST was found for older patients and patients with a lower body mass index. Lower abduction and FE tipping points were reported in patients undergoing revision rTSA for rotator cuff failure, unexplained pain, and implant wear. Discussion These tipping points can help surgeons counsel patients regarding when to undergo revision rTSA. Level of evidence Level III; retrospective cohort study; treatment study.

Background Improper sizing of the humeral head component in anatomic total shoulder arthroplasty (ATSA) can overstuff the joint, potentially compromising outcomes. The purpose of this study was to validate a novel method of evaluating glenohumeral joint overstuffing in which superoinferior and mediolateral overstuffing can be evaluated independently relative to the native humeral anatomy. Methods We identified 25 patients who underwent ATSA and the best Grashey radiograph taken within 1 year of follow-up was assessed using our proposed technique. First, a circle overlaying the implanted humeral head was made. Then, Iannotti's Perfect Circle (IPC) was drawn as originally described. Measurements of superior and medial overstuffing were made using our proposed axes. Inter-rater reliability was assessed by computing interclass correlation coefficients (ICC) using a one-way model. Measurements were summarized as the mean and range, with positive values denoting overstuffing. Results The inter-rater reliability for all measurements was excellent (ICC > 0.9). Compared to our method, the IPC method would have missed 77% of overstuffed cases. Conclusion We present a reproducible method to assess glenohumeral joint overstuffing in ATSA. This technique addresses limitations of other methods that underestimate overstuffing. Further study is needed to establish a clinically significant value of overstuffing based on the proposed method.

Background: In smaller studies, allograft-prosthetic composite (APC) has been used for proximal humerus bone loss with some success, although with notable complication risk. This systematic review and meta-analysis sought to describe outcomes and complications after proximal humerus APC and how major APC complications are defined in the literature. Methods: A systematic review was performed per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed/MEDLINE, EMBASE, Web of Science, and Cochrane were queried for articles on APC for proximal humeral bone loss secondary to tumor, fracture, or failed arthroplasty. Primary outcomes included postoperative range of motion, outcome scores (Musculoskeletal Tumor Society [MSTS], Simple Shoulder Test [SST], American Shoulder and Elbow Surgeons [ASES], Constant, visual analog scale [VAS], and subjective shoulder value [SSV]), and complication incidence. We also described individual study definitions of APC malunion/nonunion, methods of postoperative evaluation, malunion/nonunion rates, allograft fracture/fragmentation rates, and mean union time, when available. Secondarily, we compared hemiarthroplasty and reverse total shoulder arthroplasty. Results: Sixteen articles including 375 shoulders were evaluated (average age: 49 years, follow-up: 54 months). Fifty-seven percent of procedures were performed for tumors, 1% for proximal humerus trauma sequelae, and 42% for revision arthroplasty. Average postoperative forward elevation was 82° (69-94°), abduction 60° (30-90°), and external rotation 23° (17-28°). Average MSTS score was 82% (77%-87%), SST score 5.3 (4.5-6.1), ASES score 64 (54-74), Constant score 44 (38-50), VAS score 2.2 (1.7-2.7), and SSV 51 (45-58). There was a 51% complication rate with an 18% nonallograft surgical complication rate, 26% APC nonunion/malunion/resorption rate, and 10% APC fracture/fragmentation rate. Fifteen percent of nonunited APCs underwent secondary bone grafting; 3% required a new allograft; and overall revision rate was 12%. APC nonunion/malunion was defined in 2 of 16, malunion/nonunion rates in 14 of 16, fracture/fragmentation rates in 6 of 16, and mean union time (7 months) in 4 of 16 studies. Conclusion: APC reconstruction of the proximal humerus remains a treatment option, albeit with substantial complication rates. In addition, there is a need for APC literature to report institutional definitions of nonunion/malunion, postoperative evaluation, and time to union for a more standardized evaluation. Level of Evidence: Level IV ; systematic review. See Instructions for Authors for a complete description of levels of evidence.

» Benzoyl peroxide (BPO) 5% has been shown to reduce Cutibacterium acnes load on the skin. BPO 5% with miconazole nitrate (MN) 2% may be beneficial, whereas BPO 5% with clindamycin cream 1% to 1.2% does not seem to have additive effects when compared with BPO 5% alone. Chlorhexidine gluconate solutions reduce the total bacterial load on the skin, but do not seem to have a significant effect on C. acnes . » ChloraPrep seems to be the best surgical skin preparation to decrease overall positive skin cultures. Preincisional hydrogen peroxide 3% application has been shown to be a cost-effective practice to inhibit growth of C. acnes . Vancomycin powder before deltopectoral interval closure has antimicrobial effects against C. acnes and is a cost-effective practice. Finally, Bactisure surgical lavage is protective against the formation of biofilms. » IV cefazolin has been shown to be more effective for shoulder arthroplasty infection prophylaxis than antibiotic alternatives such as vancomycin. Thus, patients with a questionable history of penicillin allergy should undergo additional testing. » For shoulder surgery infection prophylaxis, we recommend the use of BPO 5% cream for 5 days preoperatively with chlorhexidine wipes the night before and the morning of surgery. IV cefazolin should be administered perioperatively, and patients with a questionable history of penicillin allergy should be tested. Surgeons should consider preincisional application of hydrogen peroxide 3% for 5 minutes, followed by standard ChloraPrep preparation. Normal saline should be used for preclosure lavage. Finally, application of vancomycin powder deep to the deltopectoral interval closure should be considered.

Background Optimal glenosphere positioning in reverse shoulder arthroplasty (RSA) remains highly debated. We aimed to characterize the association between the prosthesis scapular neck angle (PSNA) and postoperative range of motion (ROM) and clinical outcome scores. Methods A retrospective review of 284 RSAs using a single design with minimum 2-year follow-up was performed. Glenosphere tilt was measured postoperatively using PSNA. ROM and functional outcome scores were assessed preoperatively and at latest follow-up. The PSNA was dichotomized to inferior or superior groups (>90° vs ≤ 90°, respectively) and stratified into quartiles; ROM and outcome score measures were compared between groups controlling for inferior glenosphere overhang. Results No range of PSNA was consistently associated with superior ROM, clinical outcome scores, or rates of complications including scapular notching. However, greater preoperative to postoperative improvement in active FE was found for superiorly (PSNA ≤ 90°) versus inferiorly tilted glenospheres (37° ± 33° vs 53° ± 35°, P = 0.005) and the greater improvement in active FE (57° ± 35°, P = 0.004) was further isolated to the first quartile (mean 85.1° ± 3.5°). Discussion A lack of variation in clinical outcomes based on PSNA suggests negligible short-term (median follow-up 3.1 years) clinical significance when glenosphere tilt falls within the distribution of this cohort (mean 92.6° ± 6.2°).