RESUMO
Background: The rate, complexity, and cost of total shoulder arthroplasty (TSA) continues to grow. Technology has advanced pre-operative templating. Reducing cost of TSA has positive impact for the patient, manufacturer, and hospital. The aim of this study was to evaluate the accuracy of implant size selection based on 3-D templating. Our hypothesis was that pre-operative templating would enable accurate implant prediction within one size. Methods: Multicenter retrospective study of anatomic TSAs templated utilizing 3-D virtual planning technology. This program uses computed tomography (CT) scans allowing the surgeon to predict component sizes of the glenoid and humeral head and stem. Pre-operative templated implant size were compared to actual implant size at the time of surgery. Primary data analysis utilized unweighted Cohen's Kappa test. Results: 111 TSAs were analyzed from five surgeons. Pre-operative templated glenoid sizes were within one size of actual implant in 99% and exactly matched in 89%. For patients requiring a posterior glenoid augment (n = 14), 100% of implants were within one size of the template and 93% matched exactly. For stemless humeral components (n = 87) implanted, 98% matched the pre-operative template within one size with 79% exactly matched. For stemmed components (n = 24), 88% of cases were within one size of the preoperative plan and exactly matching in 83%. Humeral head diameter matched within one size of the pre-operative template in 84% of cases and exactly matched in 72%. Conclusion: Pre-operative 3-D templating for TSAs can accurately predict glenoid and humeral component size. This study sets the groundwork for utilization of pre-operative 3-D templating as a potential method to reduce overall TSA costs by managing cost of implants, reducing inventory needs, and improving surgical efficiency.
RESUMO
BACKGROUND: The treatment of complex proximal humerus fractures in the elderly with reverse total shoulder arthroplasty is an established treatment option. Healing of the greater tuberosity (GT) is associated with better outcomes. It was the aim of this cadaver study to compare the stability of GT refixation obtained with the so-called "cow hitch" cerclage fixation with that of the recommended standard suture cerclage technique. METHODS: A 4-part proximal humerus fracture was created in 10 fresh-frozen, human cadaveric shoulders. A CT was performed preoperatively to ensure the comparability of bone density and fracture patterns. In the experimental group the GT was reattached to the stem of the reverse total shoulder arthroplasty with the "cow hitch" suture cerclage (CH) technique, the conventional (CON) technique recommended for the tested implant was used in the control group. Humeri were tested with a uniaxial material testing machine. In total, 5000 loading cycles with forces from 250 to 350N were applied while motion (in mm) of the tuberosities was recorded with a telecentric camera. RESULTS: After 5000 loading cycles, the CH group showed a significantly smaller displacement of the bone fragment (0.74 ± 0.31 mm) than the CON group [2.29 ± 1.08 mm (P < .05)]. After the first three cycles the mean displacement was 0.14 mm (±0.12) in the CH and 1.42 mm (±0.21) in the CON (P < .0001) groups. CONCLUSIONS: GT reattachment with the "cow hitch" suture cerclage showed a significantly more stable fixation compared with the currently for the used prosthetic system recommended suture cerclage technique in an in vitro 4-part proximal humeral fracture model.
