Muscle force and excursion requirements and moment arm analysis of a posterior-superior offset reverse total shoulder prosthesis.

Current reverse total shoulder arthroplasty prosthesis designs do not permit offset of the humerus in the sagittal plane. Posteriorly shifting the humerus has the theoretical benefit of lengthening the infraspinatus and teres minor muscles and their external rotation moment arms, thereby improving the tension and efficiency of each external rotator and subsequently requiring each muscle to produce less force to rotate the arm. A cadaveric shoulder controller was used to quantify the impact of a novel posterior-superior offset reverse shoulder prosthesis on muscle length, moment arms, and muscle forces relative to a non-offset reverse shoulder design during two different motions: scapular plane abduction and internal/external rotation.

Differences between midvastus and subvastus TKA surgical approaches in the tasks of sitting and standing.

The mini-midvastus (MV) approach to total knee arthroplasty (TKA) minimizes damage to the extensor mechanism; however, the mini-subvastus (SV) approach is designed to avoid such damage. Quadriceps weakness following TKA can have a significant impact on the activities of daily living, particularly stand-to-sit down (STSD) and sit-to-stand up (STSU) activities. Fifty-three subjects diagnosed with primary osteoarthritis and scheduled to undergo TKA were randomized to receive an MV or SV surgical approach and were given identical postoperative orders.

Differences between standard and minimally invasive parapatellar surgical approaches for total knee arthroplasty in the tasks of sitting and standing.

Minimally invasive total knee arthroplasty (TKA) aims to enhance functional recovery and minimize trauma to the knee extensor mechanism through quadriceps sparing techniques. Few have studied the effect of TKA surgical approach on activities of daily living. Stand-to-sit-down (STSD) and sit-to-stand-up (STSU) activities are challenging for patients in constrained scenarios where upper body support is limited.