Faculty Bibliography

INTRODUCTION/BACKGROUND:The aim of this study was to evaluate the preliminary outcomes of a hybrid cage glenoid design in comparison to pegged all-polyethylene glenoid components in anatomic total shoulder arthroplasty (aTSA). MATERIALS AND METHODS/METHODS:Ninety-two patients undergoing primary anatomic total shoulder arthroplasty with minimum two-year follow-up were reviewed. Forty-six patients had an ultra-high molecular weight polyethylene (UHMWPE) cemented pegged glenoid component, and 46 had a hybrid cage glenoid component. Patient data was retrospectively reviewed from prospectively acquired data in a multi-institutional IRB approved database. These age, gender, and follow-up matched patients were evaluated and scored preoperatively and a latest follow-up using the SST, UCLA, ASES, Constant, and SPADI scoring metrics. Additional measures included active abduction, elevation, and external rotation. Radiolucent line assessment of the glenoid was performed by use of a Grashey and axillary radiograph at latest follow-up. A Student's two tailed, unpaired t-test was used to identify differences in preoperative and postoperative results, where p < 0.05 denoted a significant difference. RESULTS:All patients demonstrated significant improvements in pain and function following treatment with the primary aTSA. The database contained three complications for the aTSA patients with a cage glenoid, and three complications for patients with a UHMWPE pegged glenoid. Radiographic data was available for 37 of 46 cage glenoid patients and 29 of 46 UHMWPE pegged glenoid patients. Five of 37 cage glenoid patients had a radiolucent line (13.5%) with an average radiographic line score of 0.22. Eight of 29 UHMWPE peg glenoid patients had a radiolucent line (27.6%) with an average radiographic line score of 0.57. Cage aTSA patients were associated with significantly less blood loss than aTSA UHMWPE pegged glenoid patients (avg. blood loss = 242 vs. 337; p = 0.022). CONCLUSION/CONCLUSIONS:At minimum two-year follow-up, hybrid cage aTSA components show equal clinical outcomes to UHMWPE pegged glenoids. However, the hybrid cage components had significantly fewer radiolucent lines and less intra-operative blood loss. Additional and longer-term clinical and radiographic follow-up is necessary to confirm these promising early results.

INTRODUCTION/BACKGROUND:ASTM F2028-14 was adopted to recom mend a cyclic eccentric glenoid edge loading test that simulates the rocking horse loading mechanism beleived to cause aTSA glenoid loosening. While this method accurately simulates that failure mechanism, the recommended 750 N load may not be sufficient to simulate worst-case loading magnitudes, and the recommended 100,000 cycles may not be sufficient to simulate device fatigue-related failure modes. Finally, if greater loading magnitude or a larger number of cycles is performed, the recommended substrate density may not be sufficiently strong to support the elevated loads and cycles. To this end, a new test method is proposed to supplement ASTM F2028-14. METHODS:A series of cyclic tests were performed to evaluate the long-term fixation strength of two different hybrid glenoid designs in both low (15 pcf) and high (30 pcf) density polyurethane blocks at elevated loads relative to ASTM F2028-14. To simulate a worst case clinical condition in which the humeral head is superiorly migrated, a cyclic load was applied to the superior glenoid rim to induce a maximum torque on the fixation pegs for three different cyclic loading tests: 1. 1,250 N load for 0.75 M cycles in a 15 pcf block, 2. 1,250 N load for 1.5 M cycles in a 30 pcf block, and 3. 2,000 N load for 0.65 M cycles in a 30 pcf block. RESULTS:All devices completed cyclic loading without failure, fracture, or loss of fixation regardless of glenoid design, polyurethane density, loading magnitude, or cycle length. No significant difference in post-cyclic displacement was noted between designs in any of the three tests. Post-cyclic radiographs demonstrated that each device maintained fixa - tion with the metal pegs within the bone-substitute blocks with no fatigue related failures. DISCUSSION/CONCLUSIONS:These results demonstrate that both cemented hybrid glenoids maintained fixation when tested according to each cyclic loading scenario, with no difference in post-cyclic displacement observed between designs. The lack of fatigue-related failures in these elevated load and high cycle test scenarios are promising, as are the relatively low displacements given the extreme nature of each test. This cyclic loading method is intended to supplement the ASTM F2028-14 standard that adequately simulates the rocking horse loading mechanism but may not adequately simulate the fatigue-related failure modes.

INTRODUCTION/BACKGROUND:Osteoarthritis of the shoulder often results in significant posterior glenoid wear. The options for treating this have been eccentric glenoid reaming and occasionally bone grafting. More recently reverse total shoulder arthroplasty (rTSA) with or without bone grafting and posterior augmented glenoids (PAGs) has been introduced. The PAG restores the native joint line while reaming a minimal amount of glenoid bone. The purpose of this study is to compare osteoarthritic shoulders with significant posterior glenoid wear treated with anatomic total shoulder arthroplasty (aTSA) using a PAG to shoulders without glenoid wear treated with aTSA using a standard all poly pegged glenoid. METHODS:The patients' data in this study were retrospectively queried from prospectively acquired data in a multi-institutional IRB approved database. The study population consisted of 24 patients with osteoarthritis and posterior glenoid wear who were treated with aTSA using a PAG with a minimum of two-year follow-up. This population was age, sex, and follow-up matched to patients treated with an all poly non-augmented pegged glenoid (NAG) for osteoarthritis. Seven females and 17 males with an average age of 65.8 ± 11.5 years received a posterior augmented glenoid. The control group consisted of 7 females and 17 males with an average age of 66.4 ± 9.1 years who underwent aTSA for osteoarthritis using an all poly standard glenoid. These age, gender, and follow-up matched patients were evaluated and scored preoperatively and at latest follow-up using the SST, UCLA, ASES, Constant, and SPADI scoring metrics; active abduction, elevation, and external rotation were also measured. A Grashey and axillary lateral radiograph was evaluated at two-year follow-up. The Shoulder Arthroplasty Subluxation Index was used to determine the degree of humeral component subluxation on the glenoid component. A Student's two-tailed, unpaired t-test was used to identify differences in preoperative and postoperative results, where p < 0.05 denoted a significant difference. RESULTS:All patients demonstrated significant improvements in pain and function with the primary aTSA. Sixty per-cent of PAG shoulders had a radiolucent line with an average radiographic line score of 1.10, and 33.3% of NAG had a radiolucent line with an average radiographic line score of 0.438. One glenoid in the PAG group is radiographically but not clinically loose. In the PAG group, the Grashey view showed that 18/20 humeral heads were centered with the two remaining joints demonstrating superior subluxation. On the axillary lateral in the PAG group, 17/20 humeral heads were centered, and three were anteriorly subluxated; none were posteriorly subluxated. There were no differences in any of the measured postoperative clinical outcomes or any difference in improvement between the two groups. DISCUSSION/CONCLUSIONS:At a minimum of two-year follow-up, there were no statistical clinical differences between the PAG and NAG groups despite the PAG group being disadvantaged with posterior worn glenoids. There were no revisions in either group. No humeral heads resubluxated posteriorly. The PAG group had a higher incidence of lucent lines. Based on this short-term follow-up, a posterior augmented glenoid is a viable option for the posterior worn osteoarthritic glenoid.

Multiple different reverse total shoulder arthroplasty (rTSA) prosthesis designs are available in the global marketplace for surgeons to perform this growing procedure. Subtle differences in rTSA prosthesis design parameters have been shown to have significant biomechanical impact and clinical consequences. We propose an rTSA prosthesis design classification system to objectively identify and categorize different designs based upon their specific glenoid and humeral prosthetic characteristics for the purpose of standardizing nomenclature that will help the orthopaedic surgeon determine which combination of design configurations best suit a given clinical scenario. The impact of each prosthesis classification type on shoulder muscle length and deltoid wrapping are also described to illustrate how each prosthesis classification type impacts these biomechanical parameters.

BACKGROUND:Revision total shoulder arthroplasty to a reverse system without removing the humeral component-- i.e., a platform system--has been in use since 2006. This preliminary report compares the outcomes of revision total shoulder replacement in patients who underwent revision utilizing a platform system as compared to those patients requiring stem removal. METHODS:The data banks from two academic centers were utilized to review patients who underwent revision total shoulder surgery requiring removal of a well fixed humeral stem and those revised with a well fixed platform humeral stem. All patients underwent revision to reverse total shoulder arthroplasty. Measured variables were pre and postoperative Constant scores, blood loss, operating room time, complications, and cost. RESULTS:The use of a platform system resulted in fewer complications, less operating room time, and a decrease in blood loss (p < 0.05). The Constant scores were not significantly different between the two groups. The cost of implants and operating room time was also less in the platform system group. CONCLUSION/CONCLUSIONS:Revision total shoulder arthroplasty utilizing a platform system that does not require humeral component removal resulted in a significant decrease in complications, blood loss, and operating room time compared with revisions that did not utilize a platform system. The Constant score was similar between the two groups. The overall cost of the procedure was less when the platform system was used.

There is no consensus on surgical fixation and treatment of proximal humerus fractures, even though they are common fractures with several fixation techniques. This retrospective study quantifies the outcomes of patients who sustained a proximal humerus fracture and were treated with open reduction and internal fixation by at a single academic center between December 2010 and December 2014 using the Equinoxe® proximal humerus locking plate. Following enrollment, injury and surgical data was recorded. Forty-nine patients (31 female, 18 male) with 50 fractures were identified who met the inclusion criteria. Mean follow-up period was 16.8 months (range: 6 to 44 months). Mean age was 60.7 years with no significant difference in mean age by gender. Mean age-adjusted Charlson Comorbidity Index (CCI) was 2.9 (range: 0 to 6). The overall complication rate was 10% (N = 5) with the most common complication being osteonecrosis (N = 3). Four patients required reoperation. At final follow-up, mean active forward flexion for the cohort was 140.8º ± 30.1º, mean passive forward flexion was 155.7º ± 25.2º, and mean active external rotation was 50.1º ± 17.9º. For patients with postoperative complications, mean active forward flexion was 106.0º ± 23.0º, mean passive forward flexion was 136.7º ± 23.1º, and mean active external rotation was 34.2º ± 24.4. Active forward flexion and external rotation were significantly different in the presence of a complication (p = 0.005 and p = 0.038, respectively). Mean DASH score for the cohort was 19.1 ± 20.9. Mean DASH score for patients who developed complications or underwent reoperations was 34.2 ± 24.3. This study demonstrates that the Equinoxe® proximal humerus locking plate provides stable fracture treatment with excellent clinical results and a low complication rate when performed by experienced orthopaedic traumatologists.

In this article, we present clinical results of primary total shoulder arthroplasty for osteoarthritis using an implant that provides dual eccentricity and variable neck and version angles for reconstruction of proximal humeral anatomy. Two hundred one patients with symptomatic osteoarthritis underwent 218 total shoulder arthroplasties with a fourth-generation anatomical shoulder and a replicator plate at 4 centers between August 1, 2006, and December 31, 2010. Fourth-generation implants allow for varying humeral neck and version angles and have dual eccentricity so as to be consistently able to cover the humeral head cut. At a mean follow-up of 3 years (minimum, 2 years), there was an 81% follow-up rate. At final follow-up, 3 objective measures were significantly (P < .05) improved over preoperative levels: average active elevation (preoperative, 92°; postoperative, 137°), active external rotation (pre, 15°; post, 42°), and active internal rotation (pre, S3; post, L2). The functional outcome scores that were significantly (P < .05) improved at final follow-up were Constant normalized (pre, 39; post, 79), Shoulder Pain and Disability Index (pre, 86; post, 20), Simple Shoulder Test (pre, 3.3; post, 10), UCLA Shoulder Rating Scale (pre, 13; post, 31), and American Shoulder and Elbow Surgeons Shoulder Assessment (pre, 33; post, 85). Complications were noted in 11% of the shoulders. The most common complications were rotator cuff failure (13, 6%) and infection (5, 2%).

BACKGROUND: Shoulder arthroplasty is now used to treat an expanding variety of glenohumeral disorders. METHODS: This study assessed the demographic patterns and utilization rates of shoulder hemiarthroplasty (HA) and anatomic or reverse total shoulder arthroplasty (TSA) within New York State (NYS) from 1991 to 2010. Using the New York Statewide Planning and Research Cooperative System database, all shoulder arthroplasty procedures that occurred within NYS during the study period were retrospectively identified and analyzed. RESULTS: During the 20-year period, 24,040 shoulder arthroplasty procedures were performed. During the second decade (2001-2010), there was a 393% increase in utilization of TSA with a 98% increase in HA. This disproportionate increase is likely due to the introduction and expanding indications of reverse TSA as an effective procedure in place of HA for the treatment of proximal humerus fractures and rotator cuff arthropathy, as rotator cuff arthropathy as a primary indication for HA was significantly less prevalent in period 2. Also notable was an identifiable disparity in race; whites represented approximately 80% of the shoulder arthroplasty procedures in both decades, whereas African Americans made up <5%. This is significantly different from the general racial demographics of NYS during both periods analyzed. DISCUSSION: It is clear that the volume of shoulder arthroplasty procedures performed in NYS is increasing, mirroring the national experience. This trend reflects the expanding indications, the general success of these procedures, the aging demographic of our population, and a greater desire and willingness of patients to consider operative management to maintain or to improve quality of life.

BACKGROUND: The reverse total shoulder arthroplasty (RTSA) has been used in the treatment of complex shoulder problems. The incidence of aseptic loosening of the humeral component has not been previously reported. METHODS: This is a multicenter, retrospective, blinded, case-control radiographic review of 292 patients to determine the rate of humeral stem loosening. There were 177 cemented and 115 press-fit humeral components. Radiographs were critiqued for radiolucent lines adjacent to the humeral stem based on the method described by Gruen et al. RESULTS: The overall rate of loosening was 0.74%. No radiographic loosening occurred in the press-fit group (115 stems). In the cemented group (177 stems), 2 shoulders (1.18%) were identified with radiographically loose stems. No loosening occurred in the press-fit group. No statistically significant difference was found in humeral stem loosening when the press-fit group and the cemented group were compared (P = .198). DISCUSSION: Our study indicates the cemented or press-fit RTSA system will result in a low incidence of radiolucent lines and radiographic loosening. Compared with historical survivorship of conventional anatomic total shoulder arthroplasty, RTSA shows a lower rate of radiographic stem loosening at a mean of 38.46 months. CONCLUSIONS: The RTSA has a low incidence of humeral stem loosening at midterm. These results underscore the importance of careful selection of patients to provide the benefits of this surgical technique. Press-fit fixation may provide a lower risk to stem loosening.

The demand for spinal surgery and its costs have both risen over the past decade. In 2008 the aggregate hospital bill for surgical care of all spinal procedures was reported to be $33.9 billion. One key driver of rising costs is spinal implants. In 2011 our institution implemented a cost containment programme for spinal implants which was designed to reduce the prices of individual spinal implants and to reduce the inter-surgeon variation in implant costs. Between February 2012 and January 2013, our spinal surgeons performed 1493 spinal procedures using implants from eight different vendors. By applying market analysis and implant cost data from the previous year, we established references prices for each individual type of spinal implant, regardless of vendor, who were required to meet these unit prices. We found that despite the complexity of spinal surgery and the initial reluctance of vendors to reduce prices, significant savings were made to the medical centre. Cite this article: 2015; 97-B:1102-5.