Randall J. Otto

Scapular fractures after reverse shoulder arthroplasty: evaluation of risk factors and the reliability of a proposed classification

BACKGROUND The aims were to determine the sensitivity of plain radiographs to detect scapular fractures after reverse shoulder arthroplasty (RSA), to test the reliability of a proposed classification, and to evaluate risk factors. MATERIALS AND METHODS We matched 53 patients with scapular fractures after RSA to 212 control patients. Clinical risk factors were assessed by correlating comorbidities. Independent observers reviewed radiographs to assess fracture detection accuracy and test the reliability of a proposed classification. Radiographic risks were evaluated by measuring acromial thickness, acromial tilt, glenoid-to-tuberosity distance, and acromion-to-tuberosity (AT) distance. RESULTS Independent reviewers accurately diagnosed 78.8% of fractures and 97.4% of controls with good inter-rater reliability (κ = 0.782) and excellent intrarater reliability (κ = 0.862). Inter-rater reliability of the classification was moderate (κ = 0.422). Osteoporosis significantly increased the risk of fracture (odds ratio, 1.97; 95% confidence interval, 1.00-3.91); however, no difference was found for other comorbidities or between preoperative and postoperative radiographic parameters. A significant difference occurred between groups from the postoperative radiographs to the most recent radiographs for AT distance (0.4 ± 5.5 mm for control group and 8.3 ± 7.6 mm for fracture group, P < .001) and acromial tilt (1.8° ± 6.3° for control group and 14° ± 15° for fracture group, P < .001). Of 16 scapular spine fractures, 14 occurred from a screw tip; however, screw orientation and length were not different between groups. CONCLUSION Osteoporosis is a significant risk factor for scapular fractures after RSA. The current classification has only moderate reliability, suggesting that an alternative classification method is needed. Decreasing AT distance and increasing acromial tilt on consecutive radiographs may improve fracture detection. Advanced imaging may be needed to confirm the diagnosis. Whereas most scapular spine fractures occurred from a screw, the surgical technique did not increase the relative risk.

Reverse shoulder arthroplasty components and surgical techniques that restore glenohumeral motion

BACKGROUND Modifications in reverse shoulder arthroplasty (RSA) have been made with the intent of maximizing motion, although there is little objective evidence outlining their benefit. This study investigated the RSA component combinations that impart the greatest effect on impingement-free glenohumeral motion. METHODS A previously validated virtual shoulder model was implanted with RSA components that varied by humeral implant type (inset/onset), glenosphere diameter (30, 36, and 42 mm), glenosphere placement (inferior/neutral), glenosphere center-of-rotation offset (0, 5, and 10 mm), humeral neck-shaft angle (130° and 150°), and humeral offset (zero, five, and ten mm). Motion was simulated in all technique combinations until the point of impingement in abduction, flexion/extension (F/E), and internal/external rotation (IR/ER). Regression analysis was used to rank combinations based on motion. RESULTS Of 216 possible study combinations, 126 constructs (58%) demonstrated no arm-at-side impingement and were included for analysis. Models with the largest motion in abduction, F/E, and IR/ER, respectively, were inset-42-inferior-10-150-zero (107°), inset-36-inferior-10-130-five (146°), and inset-42-inferior-10-130-ten (121°). Humeral neck-shaft angle, glenosphere center-of-rotation offset, glenosphere placement, and glenosphere diameter had a significant effect on motion in all planes tested. Of these variables, humeral neck-shaft angle was most predictive of a change in abduction and F/E motion, whereas glenosphere placement was most predictive of a change in IR/ER motion. CONCLUSION Higher glenosphere center-of-rotation offsets led to an increase in motion in all planes. To maximize motion in abduction, a valgus humeral component should be selected; to maximize F/E, a varus humeral component should be selected; and, to maximize IR/ER, the glenosphere should be placed inferiorly.

What is the effect of postoperative scapular fracture on outcomes of reverse shoulder arthroplasty

BACKGROUND Postoperative scapular fracture is a common complication after reverse shoulder arthroplasty (RSA). The purpose of this study was to determine its effect on RSA patient outcomes. METHODS A retrospective, case-control study of 25 nonoperatively treated postoperative scapular fractures after RSA were analyzed with a minimum 2-year follow-up from surgery and 1-year follow-up from fracture. Eligible patients were matched 1:4 to a control group for age, sex, follow-up time, surgery indication, and primary operation vs revision. Outcome measures, including American Shoulder and Elbow Surgeons (ASES) score and range of motion, were compared between fracture cases and controls. Also analyzed were radiographic features, including fracture location (acromion vs scapular spine) and healing. RESULTS Incidence of scapular fracture after RSA in this series was 3.1%. Fractures occurred from 1 to 94 months postoperatively. The revision rate was higher in the fracture group (8% vs. 2%) but did not reach statistical significance (P = .18). Fracture patients had improved (ΔASES, 21) but inferior clinical outcomes, with a postoperative ASES score of 58.0 compared with 74.2 (P ≤ .001). Change in range of motion also diminished in the fracture group, with a mean gain of 26° forward elevation compared with 76° (P < .001). Fracture location (P = .54) or healing (P = .40) did not affect outcome. CONCLUSION Postoperative scapular fractures may occur at any point postoperatively; increasing incidence is likely as longer follow-up becomes available. This complication leads to inferior clinical results compared with controls. However, patients show improvement compared with their preoperative measurements, even at longer-term follow-up. Patients with postoperative scapular fractures may have increased risk of revision. LEVEL OF EVIDENCE Level III, case-control study, treatment study.

Reverse shoulder arthroplasty in patients younger than 55 years: 2- to 12-year follow-up.

BACKGROUND This study reports the outcomes of reverse shoulder arthroplasty (RSA) in patients younger than 55 years with midterm to long-term follow-up. METHODS Sixty-seven patients (average age, 47.9 years; range, 21-54 years) were identified who underwent RSA with an average 62.3 months of follow-up (24-144 months). There were 35 patients (group 1) who had a failed arthroplasty and 32 patients (group 2) who underwent primary RSA. Clinical outcomes included the American Shoulder and Elbow Surgeons (ASES) score, Simple Shoulder Test (SST) score, and range of motion. Complications included radiographic failures (fracture, dislocation, notching, loosening), infections, and nerve palsies. RESULTS Group 1 showed significant improvements in flexion and abduction but not in external or internal rotation. Group 2 showed significant improvements in flexion, abduction, and internal rotation but not in external rotation. Both groups showed significant improvements in ASES and SST scores. In group 1, ASES score improved from 24.4 to 40.8 (P = .003), and SST score improved from 1.3 to 3.2 (P = .043). In group 2, ASES score improved from 28.1 to 58.6 (P < .001), and SST score improved from 1.3 to 4.5 (P = .004). The total complication rate was 22.4%. The total reoperation rate was 13.4%, and the revision rate was 8.9%. The implant retention rate was 91% at last follow-up. CONCLUSION RSA in patients younger than 55 years provides significant clinical improvements with high implant retention at up to 12 years. Patients undergoing revision RSA begin with worse function than those undergoing primary RSA, but they can expect similar degrees of improvement. Complications were higher but reoperation rates were lower in the revision group. No mechanical failures occurred in the primary group, with infection the cause of all revisions.

Outcome of Reverse Shoulder Arthroplasty for Patients With Parkinson's Disease: A Matched Cohort Study

Parkinsons disease (PD) is a progressive neurologic disorder that affects the musculoskeletal system. Currently, the use of reverse shoulder arthroplasty (RSA) for patients with PD has not been adequately studied. The authors sought to determine if RSA provided similar functional outcomes for patients with PD compared with a matched cohort of patients without PD. Between 2004 and 2011, 10 patients with PD (4 men, 6 women) underwent RSA. Patients with PD were matched to patients without PD at a 1:4 ratio based on age (average, 76 years; range, 63-85 years), sex (16 men, 24 women), preoperative diagnosis, and length of follow-up (average, 43 months; range, 24-128 months). Outcome measures included range of motion, visual analog scale (VAS) score, Simple Shoulder Test (SST) score, American Shoulder and Elbow Society (ASES) score, and complication rates. Patients with PD had improvements in SST scores, ASES total scores, and forward flexion; however, they did not show statistically significant improvements in VAS scores, ASES function scores, or other range of motion parameters. There was a significant difference in postoperative functional outcome scores, SST scores, and internal/external rotation between the 2 groups, but no difference in postoperative pain scores, ASES total scores, forward flexion, or abduction. Complications occurred in 4 of 10 patients with PD and 6 of 40 patients without PD. Compared with the matched cohort, patients with PD achieved similar reduction of pain but inferior clinical function following RSA. Improvement in range of motion was less predictable and complication rates were significantly higher in patients with PD. [Orthopedics. 2017; 40(4):e675-e680.].

Difficulty in decision making in the treatment of displaced proximal humerus fractures: the effect of uncertainty on surgical outcomes

BACKGROUND Decision making in the management of proximal humerus fractures can be difficult in situations in which the surgeon is uncertain of the ideal treatment. METHODS Two shoulder surgeons operatively treated 476 proximal humerus fractures from 1998-2014 with open reduction-internal fixation (ORIF), hemiarthroplasty, or reverse shoulder arthroplasty. Operative treatment was stratified by year to determine the evolution of technological influences on treatment over time. To evaluate the effect of uncertainty, 274 clinical vignettes were created for all patients with 1 year of follow-up or more and reviewed by 3 fellowship-trained shoulder surgeons to determine the type of treatment for each case. To evaluate the effect of certainty, range of motion for each patient with unanimous agreement on treatment was analyzed. RESULTS ORIF treatment increased from 40% to 62% after release of the proximal humerus locking plate. Introduction of the fracture stem in 2011 increased reverse shoulder arthroplasty for fractures from 8.8% to 44.3%. Unanimous agreement on either operative or nonoperative treatment occurred 70.5% of the time. Only 63.5% of patients received the actual treatment selected (P = .001). Patients for whom unanimous agreement matched actual treatment in the ORIF treatment group showed improvement of forward elevation (144° vs 123°, P = .005) and abduction (129° vs 103°, P = .002). CONCLUSION Successful management of displaced proximal humerus fractures requires both technical and decision-making abilities. The difficulty in making these decisions is reflected by the agreement of experienced shoulder surgeons only 63.5% of the time regarding the treatment performed. When uncertainty occurs, patients may have reduced outcomes as seen in the ORIF treatment group.

Classification of instability after reverse shoulder arthroplasty guides surgical management and outcomes

BACKGROUND Revision of unstable reverse shoulder arthroplasty (RSA) remains a significant challenge. The purpose of this study was to determine the reliability of a new treatment-guiding classification for instability after RSA, to describe the clinical outcomes of patients stabilized operatively, and to identify those with higher risk of recurrence. METHODS All patients undergoing revision for instability after RSA were identified at our institution. Demographic, clinical, radiographic, and intraoperative data were collected. A classification was developed using all identified causes of instability after RSA and allocating them to 1 of 3 defined treatment-guiding categories. Eight surgeons reviewed all data and applied the classification scheme to each case. Interobserver and intraobserver reliability was used to evaluate the classification scheme. Preoperative clinical outcomes were compared with final follow-up in stabilized shoulders. RESULTS Forty-three revision cases in 34 patients met the inclusion for study. Five patients remained unstable after revision. Persistent instability most commonly occurred in persistent deltoid dysfunction and postoperative acromial fractures but also in 1 case of soft tissue impingement. Twenty-one patients remained stable at minimum 2 years of follow-up and had significant improvement of clinical outcome scores and range of motion. Reliability of the classification scheme showed substantial and almost perfect interobserver and intraobserver agreement among all the participants (κ = 0.699 and κ = 0.851, respectively). DISCUSSION Instability after RSA can be successfully treated with revision surgery using the reliable treatment-guiding classification scheme presented herein. However, more understanding is needed for patients with greater risk of recurrent instability after revision surgery.

Total shoulder arthroplasty with minimum 5-year follow-up: does the presence of subchondral cysts in the glenoid increase risk of failure?

BACKGROUND This study evaluated the effect of cystic changes in the glenoid on postoperative outcomes and implant survival after total shoulder arthroplasty (TSA). MATERIALS AND METHODS From 2004 to 2012, 75 patients underwent TSA for primary osteoarthritis with minimum 5-year follow-up. Preoperative 3-dimensional models based on computed tomography imaging were created for all patients. A qualitative evaluation of cystic osteoarthritis was performed through survey grading by 3 fellowship-trained shoulder surgeons. The extent of cyst formation in the glenoid (no cysts, small, medium, or large) was assigned for every patient. In addition, quantitative evaluation was performed on 3-dimensional glenoid models. Functional outcomes, radiographic findings, and the need for revision were compared between group 1 (large and medium cysts) and group 2 (small and no cysts). RESULTS Qualitative evaluation of cyst formation resulted in the following distribution: no cysts in 8 patients (11%), small cyst formation in 27 (36%), medium cysts in 19 (25%), and large cysts in 21 patients (28%; κ = 0.605). The difference in total cyst volume between group 1 and group 2 was significant (P = .004). The overall revision rate was 7% (5 of 75). All revised patients were in the groups with medium or large cysts. There were no statistical differences in American Shoulder and Elbow Surgeons (ASES) Standardized Shoulder Assessment scores or presence of radiographic loosening among the study groups. CONCLUSION Qualitative computed tomography evaluation of cystic osteoarthritis correlates with quantitative analysis of cyst volume. Severe cyst formation portends a higher risk of failure at midterm follow-up. Cystic disease did not affect functional outcome or the presence of radiographic glenoid loosening.

Reverse Shoulder Arthroplasty in the Setting of Scapula Fractures

Scapula fractures after reverse shoulder arthroplasty (RSA) may occur in 0.9–10 % of patients. Osteoporosis is a risk factor, so these patients should be counseled on the risk of fracture and treated appropriately. While preoperative acromial insufficiency does not affect outcomes, the clinical outcomes in postoperative fracture patients has been found to be inferior to control patients. A high clinical suspicion is necessary if a patient presents with pain over the scapula or acromion. A computed tomography scan may be necessary to make the diagnosis since plain radiographs are not reliable. The surgeon can improve the detection of fractures on sequential plain radiographs by observing a decreasing distance between the acromion and greater tuberosity (AT) as well as an increasing acromial tilt angle between the scapular spine and acromial body. Once diagnosed, the patient should be immobilized for 6 weeks and then gradually progressed to activities as tolerated. Acromial base or scapular spine fractures may increase the risk of instability and need for revision surgery. Fracture healing has not been found to affect outcome, and with a high complication rate of surgery, surgical fixation of the fractures is not recommended.