Faculty Bibliography

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.

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: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.

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.

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.

Subscapularis tenotomy for anatomic total shoulder arthroplasty has been the standard approach for shoulder surgeons that use the deltopectoral approach. The risk of subscapularis insufficiency after this approach has been well documented. In order to avoid subscapularis complications, subscapularis sparing approaches through the rotator interval have been developed. We present two alternative subscapularis preserving techniques that are performed through the deltopectoral interval and allow more complete osteophyte excision and accurate humeral head sizing. These techniques require modified instrumentation and are facilitated by the use of an adaptable prosthesis with dual eccentricity. Future studies will examine the comparative clinical and radiographic outcomes of these techniques.

INTRODUCTION/BACKGROUND:Indications for anatomic (aTSA) and reverse (rTSA) total shoulder arthroplasty are well defined and dependent on the function of the rotator cuff; however, indications for rTSA have gradually extended to complex fractures, revisions, and primary arthritis in very elderly patients. The risk of secondary rupture of a weakened or degenerative rotator cuff is difficult to assess and can lead the orthopaedic surgeon to hesitate between aTSA or rTSA. It, therefore, seems appropriate to compare these two types of prostheses in terms of pain, functional, clinical outcome metric scores, and complications, despite suspected differences between populations and the respective diseases. METHODOLOGY/METHODS:1,145 patients (69.2 ± 8.9 years) were treated by 12 orthopaedic surgeons in France and in the USA, using either aTSA or rTSA with one platform shoulder system. Five hundred twenty-eight patients received aTSA (66.2 ± 9.0 years; 283 female, 245 male) for treatment of degenerative arthritis, and 617 patients received rTSA (71.8 ± 8.0 years; 392 female, 225 male) for treatment of cuff tear arthroplasty, rotator cuff tear, and osteoarthritis. Each patient was scored preoperatively and at latest follow-up using the SST, UCLA, ASES, Constant, and SPADI metrics; active range of motion was also measured. The average follow-up for all patients was 39.7 ± 18.7 months (aTSA: 42.7 ± 21.9 months; rTSA: 37.1 ± 15.1 months). Improvements in outcome using each metric score were normalized on a 100 point scale, correlated, and compared. A Student's two-tailed, unpaired t-test was used to identify differences in preoperative, postoperative, and pre-to-postoperative improvements, where p < 0.05 denoted a significant difference. RESULTS:Preoperatively, rTSA patients had significantly lower mean outcome scores and significantly lower mean active range of motion as compared to aTSA patients. Post-operatively, rTSA and aTSA patients showed no significant difference in active forward flexion or in mean outcome scores as measured by four of the five metrics. rTSA patients had significantly lower active abduction, internal rotation, and active and passive external rotation than aTSA patients. However, they had significantly better strength (9.7 vs. 7.3 lbs, p < 0.0001). Preoperative to postoperative mean improvements were compared between both cohorts. rTSA patients were associated with significantly larger improvements in outcomes and also had significantly better improvements in active forward flexion and strength. Conversely, aTSA patients had significantly better improvement in active and passive external rotation and active internal rotation. Analysis of complications demonstrated a very similar rate between cohorts, with aTSA patients associated with a slightly lower rate (6.6 vs. 7.3%). CONCLUSION/CONCLUSIONS:This retrospective analysis of prospectively acquired data from 1,145 patients who received either a primary aTSA or rTSA prosthesis demonstrates that each device provides significant improvements with very similar mean results. In fact, the mean clinical outcomes associated with the reverse shoulder prostheses approach that of the "gold standard" anatomic device for their respective indications. Furthermore, the complication rates in this series are very similar and also favorable relative to the clinical literature. Findings, such as these, may at some point extend the indications of the reverse prosthesis to patients for whom an anatomical prosthesis could lead to a premature deterioration of the result.

INTRODUCTION: Paul Grammont's hemispherical gleno sphere concept medializes the center of rotation (CoR) to the glenoid face to increase deltoid abductor moment arms and improve muscle efficiency. Reducing glenosphere thickness to less than half its spherical radius further medializes the CoR and offers the potential for even greater improvements in efficiency. To that end, this study quantifies deltoid abducttor moment arms for six different rTSA prostheses during scapular abduction from 0 degrees to 140 degrees . METHODS: A 3D computer model was developed in Uni graphics to quantify deltoid moment arms during scapular abduction for the normal anatomic shoulder, the 36 mm Grammont Delta III (Depuy, Inc.), 36 mm BIO-RSA (R) (Tornier, Inc.), the 32 mm RSP(R) (DJO, Inc.), and the Equinoxe(R) rTSA (Exactech, Inc.) with three different glenosphere geometries: 38 mm x 21 mm, 46 mm x 25 mm, and the novel 46 mm x 21 mm. Each muscle was simulated as three lines from origin to insertion as the arm was elevated; positional data was exported to Matlab where the abductor moment arms were calculated for the anterior, middle, and posterior deltoid from 0 degrees to 140 degrees humeral abduction in the scapular plane using a 1.8:1 scapular rhythm. RESULTS: The 46 mm x 21 mm glenosphere had the larg est average abductor moment arms and also the largest efficiency for all three heads of the deltoid, having a 4.8% to 40.7% increase in the average deltoid efficiency relative to all other designs tested. The glenosphere design with the next most efficient deltoid was the 36 mm Delta III, which had the next most medialized CoR. The two least efficient designs were the BIO-RSA (R) and the DJO RSP(R) , which had the most lateral CoR. DISCUSSION: These results provide new biomechanical insights on the impact of glenosphere geometry on deltoid abductor moment arms and demonstrate that subtle changes in rTSA prosthesis design can result in dramatic improvements. Increasing glenosphere diameter while also decreasing thickness to be less than half its spherical radius may minimize the muscle forces required to perform activities of daily living. Clinical follow-up is necessary to demonstrate a reduction in complications related to joint over-loading and also demonstrate greater increases in range of motion for patients with weak musculature.

Body Mass Index (BMI) is one of the metrics used to assess overall health and has been implicated in having predictive value in many aspects of health, including outcomes after shoulder replacement surgery. Outcome data from a multi- institutional database with an average follow-up period of 39.8 months (minimum 24-months) demonstrated that all patients, regardless of BMI, improved significantly after treatment with anatomic total shoulder arthroplasty (aTSA) or reverse total shoulder arthroplasty (rTSA). Improvements in outcomes were stratified and compared based upon BMI in three groups: less than 25, 25 to 35, and greater than 35. Comparing these measures demonstrated that aTSA patients with higher BMI were generally associated with lower functional postoperative outcome metric scores than aTSA patients with lower BMI, though the preoperative to postoperative gains were generally equivalent regardless of BMI. Interestingly, postoperative outcome metric scores with rTSA patients were equivalent regardless of BMI as were the pre-to-postoperative gains. Additionally, differences in the magnitude of pre-to-postoperative improvement of range of motion (ROM) measurements between patients of BMI less than 25 and BMI greater than 35 were noted for forward flexion, internal rotation, and active and passive external rotation. The actual clinical significance of these differences is unknown. Finally, patients with lower BMI appeared to have a higher incidence of low-grade scapular notching.