METHODS

Ten different surgeons performed a total of 37 rTSA cases with the same implant system. During the procedure, each surgeon reconstructed the rTSA implants to his or her own preferred tension. A wireless load sensing humeral liner trial (VERASENSE for Equinoxe, OrthoSensor, Dania Beach, FL) was used in lieu of a traditional plastic humeral liner trial to provide real-time load data to the operating surgeon during the procedure. Two humeral liner trial sizes were offered in 38mm and 42mm curvatures and were selected each case based on surgeon preference. To ensure consistent measurements between surgeons, a standardized ROM assessment consisting of four dynamic maneuvers (maximum internal to external rotation at 0°, 45°, and 90° of abduction, and a maximum flexion/extension maneuver) and three static maneuvers (arm overhead, across the body, and behind the back) was completed in each case. Deidentified load data in lbf was collected and sorted based on which size liner was selected. Differences in means for minimum and maximum load values for the four dynamic maneuvers and differences in means for the three static maneuvers were calculated using 2-tailed unpaired t-tests.

METHODS

172 ASES members completed an 18-question survey on their thought process for how they select and place a glenoid implant for both ATSA and RTSA procedures. Data was collected using a custom online Survey Monkey survey. Surgeon answers were split into three cohorts based on their responses to usage of 3D preoperative planning software: high users, seldom users, and non-users. Data was analyzed for each cohort to examine differences in thought patterns, implant selection, and implant placement.

METHODS

172 ASES members completed an 18-question survey on their thought process for how they select and place a RTSA glenoid implant. Data was collected using a custom online Survey Monkey survey. Surgeon answers were split into two cohorts based on number of arthroplasties performed per year: between 0–75 was considered low volume (LV), and between 75–200+ was considered high volume (HV). Data was analyzed for each cohort to examine differences in thought patterns, implant selection, and implant placement.

METHODS

172 ASES members completed an 18-question survey on their thought process for how they select and place an ATSA glenoid implant. Data was collected using a custom online Survey Monkey survey. Surgeon answers were split into two cohorts based on number of arthroplasties performed per year: between 0–75 was considered low volume (LV), and between 75–200+ was considered high volume (HV). Data was analyzed for each cohort to examine differences in thought patterns, implant selection, and implant placement.

METHODS

High resolution 1mm slice thickness CT scans were obtained on 30 cadaveric shoulders from 15 matched pair specimens. Each scan was segmented and the digital models were incorporated into a preoperative planning software. Five fellowship trained orthopedic shoulder specialists used this software to virtually place a rTSA glenoid implant as they deemed best fit in six cadavers each. The specimens were randomized with respect to side and split into a cohort utilizing the CAS system and a cohort utilizing conventional instrumentation, for a total of three shoulders per cohort per surgeon. A BaSO₄ PEEK surrogate implant identical in geometry to the metal implant used in the preoperative plan was used in every specimen, to maintain high CT resolution while minimizing CT artifact. The surgeons were instructed to implant the rTSA implants as close to their preoperative plans as possible for both cohorts. In the CAS cohort, each surgeon used the system to register the native cadaveric bones to each respective CT, perform the TSA procedure, and implant the surrogate rTSA implant. The surgeons then performed the TSA procedure on the opposing side of the matched pair using conventional instrumentation.

Postoperatively, CT scans were repeated on each specimen and segmented to extract the digital models. The pre- and postoperative scapulae models were aligned using a best fit match algorithm, and variance between the virtual planned position of the implant and the executed surgical position of the implant was calculated [Fig 1].

Method

Using the capacitive load sensing technology embedded in instrumented tibial trays, a wireless, instrumented humeral trial has been developed. The wireless communication enables real-time display of the three-dimensional load vector and load magnitude in the glenohumeral joint during component trialing in RTSA. In an in-vitro setting, this sensor was used in two reverse total shoulder arthroplasties. The resulting load vectors were captured through the range of motion while the joint was artificially tightened by adding shims to the humeral tray.

METHODS

CT scans from 45 patients with glenohumeral arthritis were planned by 8 fellowship trained shoulder arthroplasty specialists using a 3D preoperative planning software, planning each case for optimal implant selection and placement. The software provided three implant types: a standard non-augmented glenoid component, and an 8° and 16° posterior augment wedge glenoid component. The software interface allowed the surgeons to control version, inclination, rotation, depth, anterior- posterior and superior-inferior position of the glenoid components in 1mm and 1° increments, which were recorded and compared for final implant position in each case.

METHODS

CT scans from 45 patients with glenohumeral arthritis were planned by 8 fellowship trained shoulder arthroplasty specialists using a 3D preoperative planning software, planning each case for optimal implant selection and placement. The software provided four glenoid baseplate implant types: a standard non-augmented component, an 8° posterior augment wedged component, a 10° superior augment wedged component, and a combined 8° posterior and 10° superior wedged augment component. The software interface allowed the surgeons to control version, inclination, rotation, depth, anterior-posterior and superior-inferior position of the glenoid components in 1mm and 1° increments, which were recorded and compared for final implant position in each case.

Methods

427 patients (mean age: 67.0yrs) with an average follow-up of 49.4 months was treated with aTSA for OA by 14 fellowship trained orthopaedic surgeons. Of these 427 patients, 293 had a cemented keel glenoids (avg follow-up = 50.8 months) and 134 had a cemented pegged glenoids (avg follow-up = 48.7 months). Cemented peg and keel glenoid patients were analyzed separately and also combined into 1 cohort: 288 patients (158 female, avg: 68.7 yrs; 130 male, avg: 64.9 yrs) did not have a radiolucent glenoid line (avg follow-up = 46.9 months); whereas, 139 patients (83 female, avg: 68.5 yrs; 56 male, avg: 64.6 yrs) had a radiolucent glenoid line (avg follow-up = 54.4 months). Outcomes were scored using SST, UCLA, ASES, Constant, and SPADI metrics; active ROM also measured. A two-tailed, unpaired t-test identified differences (p<0.05) in pre-operative, post-operative, and pre-to-post improvements.

Methodology

This is a multicenter, retrospective, case controlled radiographic and clinical review. Preoperative and postoperative data was analyzed from 671 aTSA patients with a minimum of 2 years followup. 538 of these 671 aTSA patients had full radiographic followup (80.2%) and were included in this study; these patients had an average followup of 45.3 months). 459 patients had noncemented humeral stems; whereas, 79 patients had cemented humeral stems. Radiographs were reviewed at latest follow up for humeral radiolucent lines based on the technique described by Gruen et al. Patients were evaluated and scored pre-operatively and at latest follow-up using the SST, UCLA, ASES, Constant, and SPADI scoring metrics; ROM was also recorded. A Student's two-tailed, unpaired t-test was used to identify differences in pre-operative, post-operative, and improvement in results, where p<0.05 denoted a significant difference.

METHODS

Nine cadaveric shoulders were CT scanned with .5mm slice thickness, and the digital models were incorporated into a preoperative planning software. Five orthopedic shoulder specialists used this software to virtually place aTSA and rTSA glenoid components in two cadavers each (one cadaver was omitted due to incomplete implantation), positioning the components as they best deemed fit. Using a navigation system, each surgeon registered the native cadaveric bone to each respective CT. Each surgeon then used the navigation system to guide him or her through the total shoulder replacement, and implant the barium sulfate impregnated PEEK surrogate implants. Four cylindrical PEEK fiducials were also implanted in each scapula to help triangulate the position of the surrogate implants. Previous efforts were attempted with stainless steel alloy fiducials, but position and image accuracy were limited by CT artifact. BaSO₄ PEEK provided the highest resolution on a postoperative CT with as little artifact as possible. All PEEK fiducials and surrogate implants were registered by probing points and planes with the navigation system to capture the digital position. A high resolution post operative CT scan of each specimen was obtained, and variance between the executed surgical plan and PEEK fiducials was calculated.

Methods

8 reverse shoulder baseplate/glenosphere assemblies (Equinoxe, Exactech, Inc) were fixated to 15 lb/ft3 density rigid polyurethane bone substitute blocks. Displacement of the assemblies in the A/P and S/I axes was measured using digital displacement indicators by applying a physiologically relevant 357N shear load parallel to the face of the glenosphere, and a nominal 50N compressive axial load perpendicular to the glenosphere. Westerhoff et al. reported in vivo shoulder loads while ambulating with axillary crutches had a maximum resultant force of 170% times the patient's bodyweight with the arm at 45.25° of abduction1. This was recreated by applying a 1435.4N compressive load (Average bodyweight of 86.1kg*170%) to a humeral liner and reverse shoulder assembly in an Instron testing apparatus at 45.25° of abduction as shown in Figure 1. The glenosphere was rotated about the humeral component through the arc of the axillary crutch swing, from −5° of extension to 30° of flexion as shown in Figure 2 for 183,876 cycles2. The number of cycles was based on number of steps taken in a day from pedometer data reported by Tudor Locke et al. for patients with movement disorders, extrapolated out to a 6 week postoperative recovery period3. A Student's one-tailed, paired t-test was used to identify whether or not significant displacement occurred, where p<0.05 denoted a significant difference.

Methods

A total of 5 shooters over a range of heights and bodyweights fired a single action 12 gauge shotgun with 3 ounce slugs 5 times each. An accelerometer was rigidly fixated to the barrel of the firearm to record impulse values upon firing. 8 reverse shoulder baseplate/glenosphere assemblies (Equinoxe, Exactech, Inc) were fixated to 15 lb/ft3 density rigid polyurethane bone substitute blocks for drop tower testing. Displacement was measured before and after testing using digital displacement indicators by applying a physiologically relevant 357N shear load parallel to the face of the glenosphere, and a nominal 50N compressive axial load perpendicular to the glenosphere as shown in Figure 1. Measurements were taken for the S/I axis, and the sample was rotated 90 degrees for the A/P axis. The glenosphere/baseplate assemblies were loaded in a drop tower apparatus at 0° of abduction and 90° flexion to replicate the orientation of the joint seen while shooting. The drop tower utilized a 1.079kg weight set at 8” with a rubber impulse specific materil between the weight and impactor to reproduce the highest average impulse seen in shooting. A total of 50 drops were performed, to simulate two rounds of trap shooting at 25 shots each. A Student's one-tailed, paired t-test was used to identify whether or not significant loosening occurred, where p<0.05 denoted a significant difference.