Faculty Bibliography

INTRODUCTION/BACKGROUND:Numerous anatomic studies of the shoulder have quantified the size, shape, and variability of either the humerus or scapula individually. However, few have attempted to quantify the relationship of the humerus to the scapula to better understand the spatial variation of these bones in both male and female shoulders. METHODS:Seventy-four cadaveric shoulder CT scans (37 males and 37 females with statistically equivalent age and BMI) were reconstructed using Mimics ® to create 3D models of the humerus and scapula. After 3D reconstruction, each CT bone model was analyzed in Rapidform® to quantify the morphology of the humerus, scapula, and the spatial relationship between the two to better understand the role of gender on the morphological variability of the glenohumeral joint. RESULTS:Spatial glenohumeral relationships of male shoulders were significantly larger than female shoulders in 13 of 16 measurements; morphology of male humeri were significantly larger than female humeri in 17 of 24 measurements, and scapula and glenoid morphology of male shoulders were significantly larger than female scapula and glenoids in 11 of 22 measurements. DISCUSSION/CONCLUSIONS:Numerous significant gender differences in spatial relationships and morphology were identified in this anatomic study of the glenohumeral joint. An improved understanding of these observed binomial distributions has utility for shoulder arthroplasty prosthesis design, computer navigation, and may also be useful to the orthopaedic surgeon during surgical preoperative planning.

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.

UNLABELLED:Many glenohumeral studies have demonstrated how anatomy varies across the population. Third and fourth generation shoulder prosthesis designs were developed to provide greater modularity and size ranges to better reproduce this anatomy and thus achieve better results in terms of shoulder function. This study quantifies the quality of anatomic reconstruction and compares that to long-term clinical outcomes using one fourth generation platform shoulder system. METHODOLOGY/METHODS:One hundred and forty primary total shoulder arthroplasties were performed by one experienced single surgeon between 2001 and 2009, using the same fourth generation modular prosthesis. Pre- and postoperative clinical assessments were quantified with the Constant, ASES, SPADI, SST, and UCLA scores, and active range of motion was measured. Five anatomic parameters were defined, measured, and compared pre- and postoperatively on the anterior-posterior (AP) radiographs: Humeral Head Height (HHH), Humeral Head Centering (HHC), Humeral Head Medial Offset (HHMO), Humeral Head Diameter (HHD), and Humeral Neck Angle (HNA). The differences between each of the parameters were then calculated and rated from 0 to 2 and then summed for each patient to obtain the Anatomic Reconstruction Index (ARI), which objectively quantifies and assesses the quality of the anatomic reconstruction. Patients were sorted based upon their ARI score into two groups (ARI 5 to 7 and ARI 8 to 10), and their latest follow-up outcomes were compared using the Mann-Whitney test to identify differences in preoperative and postoperative results, where p < 0.05 denoted a significant difference. RESULTS:Of the 140 primary prostheses performed, 78 patients were lost to follow-up, and 13 were excluded for complications that were not related to the anatomic reconstruction. Forty-nine patients (75.8 yrs., 31F/18M) were included with an average follow-up of 9.1 years. The average score for HHH was 1.9 ± 0.4, 1.8 ± 0.5 for HHC, 1.7 ± 0.5 for HHMO, 1.7 ± 0.5 for HHD, and 1.5 ± 0.7 for HNA. Thus, all reconstructions were rated good to excellent with 86% of very good/excellent reconstruction (ARI 8 to 10) and 14% good reconstruction (ARI 5 to 7). A comparison of radiographic anatomic parameters was performed for these two cohorts: HHC (< 0.0001), HNA (0.000), and ARI (<0.0001) were significantly greater for the ARI 8 to 10 cohort. Four of five postoperative clinical outcome metrics for the ARI 8 to 10 cohort were significantly greater than the mean values for the ARI 5 to 7 cohort. Additionally, mean postoperative pain on a daily basis and shoulder function for the ARI 8 to 10 cohort were significantly greater than that for the ARI 5 to 7 cohort. DISCUSSION/CONCLUSIONS:The relatively small number of good reconstructions (14%) compared to very good/excellent reconstructions (86%) and the absence of fair/poor reconstructions limited the ability for any strong linear correlations between anatomical reconstruction and clinical parameters. Despite this, patients with larger mean ARI scores were associated with significantly better outcomes for some measures. This study is limited by the use of 2D assessments from standard AP radiographs; this method can be further refined by the use of 3D quantitative assessment of each parameter. CONCLUSION/CONCLUSIONS:This study confirmed that an improved anatomic reconstruction results in better postoperative clinica outcomes. The fourth generation prosthesis used for this study allows continuous in-situ adjustment of the humeral head orientation through use of the spherical taper on the replicator plate and also a double adjustment of offset through the use of the offset humeral head and offset taper on the replicator plate.

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.

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.

INTRODUCTION/BACKGROUND:Patients who are candidates for a reverse total shoulder arthroplasty (rTSA) may have varying amounts and patterns of glenoid wear. The usual treatment of these deformities has been eccentric reaming or bone grafting. Eccentric reaming often removes a large amount of subchondral bone. Bone grafting is technically more difficult and introduces another mode of failure if the graft does not heal. The purpose of this study is to evaluate patients undergoing a rTSA with concomitant superior or posterior glenoid wear who were treated with a superior augmented baseplate (SAB) or posterior augmented baseplate (PAB) without eccentric reaming or bone grafting. MATERIALS AND METHODS/METHODS:Prospectively obtained data were queried from a multi-institutional IRB-approved database. Preoperative and postoperative data were analyzed from 39 patients who received a primary rTSA with either an 8° PAB or a 10° SAB and a minimum of 2 years follow-up. Twenty-four (10 females and 14 males, aged 72.3 ± 8.2 years) received a primary rTSA shoulder with a PAB. Fifteen patients (4 females and 11 males, aged 71.7 ± 9.2 years) received a primary rTSA shoulder with a SAB. Each patient was scored preoperatively and at latest follow-up using the SST, UCLA, ASES, Constant, and SPADI metrics. Active abduction, forward flexion, and active and passive external rotation with the arm at the side were also measured. The average follow-up for rTSA patients with a PAB was 25.6 ± 3.1 months, and the average follow-up for rTSA patients with a SAB was 32.5 ± 6.5 months. 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 in both groups demonstrated significant improvements in pain and function following treatment with the reverse shoulder arthroplasty. The PAB rTSA cohort had a scapular notching rate of 6.3%, whereas the SAB rTSA cohort had a scapular notching rate of 14.3%. The PAB outperformed the SAB with the ASES, Constant, and active forward elevation measures. DISCUSSION/CONCLUSIONS:The PAB group outperformed the SAB group with the ASES and Constant outcome scores and forward flexion. The reason for this is unknown; however, it may be due to the posterior augment baseplate itself tensioning the remaining external rotators better than the superior augment, or it may be that the posterior augment group had a better posterior cuff. Both implant groups had no revisions or dislocations and had a low notching rate. It appears that a SAB for superior glenoid wear and a PAB for posterior glenoid wear are viable simple solutions in patients undergoing a rTSA, where each preserves glenoid bone and eliminates the need for glenoid bone grafting.

INTRODUCTION/BACKGROUND:The rate of clinical improvement has never been studied after anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty. This study quantifies the rate of improvement after aTSA and rTSA using five different scoring metrics for 1,641 patients. METHODS:We evaluated 1,641 (69 ± 9.3 years old) patients treated by 14 orthopaedic surgeons using either aTSA or rTSA with a single platform shoulder system. Seven hundred twenty-nine patients received aTSA, and 912 patients received rTSA. Each patient was scored preoperatively and at various follow-up intervals (2 weeks, 6 weeks, 3 months, 6 months, annually, etc.) with a maximum follow-up time of 139 months using the SST, UCLA, ASES, Constant, and SPADI metrics. In addition, range of motion was measured. The rate of improvement was analyzed using a 40-point moving filter treadline over the entire range of follow-up. RESULTS:All metrics improved in a majority of patients with less than 5% worsening after 6 months. While gains in motion were present in the majority of patients after aTSA, a higher incidence of patients failed to experience improvement in range of motion after rTSA. Clinical worsening was seen in up to 10% and 20% of the visits for active flexion and abduction and external rotation, respectively. The majority of clinical improvement after aTSA and rTSA was noted in the first 6 months with full improvement noted by 12 to 24 months. During the first 12 months, the rate of improvement associated with rTSA patients was generally 30% larger than that of aTSA patients. DISCUSSION/CONCLUSIONS:The results of this large-scale database analysis demonstrate the reliability of improvements in outcomes and motion achieved with both aTSA and rTSA for various indications. For both aTSA and rTSA, less than 5% of patients reported worsening in each of the five clinical metrics after 6 months postoperative follow-up time. This study is significant because it quantifies how patient outcomes improve with time following treatment with both aTSA and rTSA. These results can be used to establish realistic patient expectations regarding the typical follow-up time required for pain to be reduced and function restored following surgical treatment with a total shoulder prosthesis.

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.