Successful total shoulder arthroplasty relies on a multitude of factors specific to patients, implant selection, and surgical technique. Among technical factors, correct intraoperative placement of ...prosthetic components is paramount. Three-dimensional computed tomography has emerged as a vital tool, allowing surgeons to measure glenoid inclination, glenoid version, and humeral head subluxation more accurately and reproducibly. Several commercial preoperative planning software resources are available to determine the optimal size and positioning of prosthetic components yet do so at significant cost and with meaningful time constraints. At our institution, we have applied the principles of these technologies to develop a custom, 3-dimensionally printed glenoid guide for accurate placement of the central pin. In this technical note, we describe our evaluation of patients with glenohumeral arthritis, as well as our step-by-step procedure for designing and printing a custom patient-specific instrumentation glenoid guide for anatomic total shoulder arthroplasty.
The proposed benefits of stemless humeral implants include greater bone preservation, decreased cortical stress shielding, less risk of diaphyseal stress risers, decreased surgical time, and greater ...ease of implant removal during revision surgery. In part 3 of this comprehensive technique series on the management of glenohumeral arthritis, we present our step-by-step surgical technique for use of a patient-specific 3-dimensionally printed glenoid drill guide, placement of a stemless anatomic total shoulder prosthesis, and subscapularis repair, and we highlight our protocol for postoperative rehabilitation.
Implant-free press-fit tibial fixation technique has recently gained popularity in anterior cruciate ligament reconstruction because it does not cause tunnel widening, does not cause complications ...associated with additional fixation materials, allows bone-to-bone healing, and does not cause defects in revision surgery. Bone-patellar tendon autograft offers the advantage of direct bone-to-bone integration of the graft, and anterior knee pain is less expected than bone-patellar tendon-bone autograft. This technical report includes details of arthroscopic ACL reconstruction of patellar tendon-tibial tubercle bone autograft distal press-fit fixation technique. We call this the Kocabey distal press-fit technique.
Hamstring tendons are a very commonly used autograft for anterior cruciate ligament (ACL) reconstruction. Given that larger hamstring graft diameter has been shown to positively affect outcomes after ...ACL reconstruction, several techniques have been developed to optimize this variable. In this technical note, we describe the operative technique for generation of a 5-strand hamstring autograft via tripling of the semitendinosus tendon and doubling of the gracilis tendon, which can serve to maximize graft diameter, especially in patient populations with undersized hamstring tendons at baseline.
Most information systems (IS) research develops theory for explanation and prediction based on a variance logical structure that assumes one-way, time invariant causal relationships. This approach ...largely misses the opportunity to extend theory from alternative logical structures that build upon reciprocal and temporal causal mechanisms; for example, the system perspective. This paper introduces system dynamics (SD), a modeling tool capable of capturing the reciprocal and temporal causal mechanisms that underlie many complex and dynamic systems, and demonstrates its ability to extend existing variance theory from a system perspective. To do so, we first describe the basic tenets of SD and discuss the status quo of existing SD applications in the field. Then, we demonstrate how to model SD’s unique theoretical logic of reciprocal and temporal causal structure to extend existing variance theory. To demonstrate the use of SD in theory development, we develop and validate an SD model of the e-commerce resource endowment of a click-and-mortar firm and simulate dynamic causal relationships between the e-commerce resource endowment and firm performance over time, under various scenarios. This case demonstrates how we can extend an existing variance theory by reconciling the inconsistent findings of prior research from a system perspective using the SD approach. The paper concludes by discussing how SD can help IS researchers develop dynamic theories.
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