Combining novel diverse population-based software with a clinically-demonstrated implant design is redefining total hip arthroplasty. This contemporary stem design utilized a large patient database of high-resolution CT bone scans in order to determine the appropriate femoral head centers and neck lengths to assist in the recreation of natural head offset, designed to restore biomechanics. There are limited studies evaluating how radiographic software utilizing reference template bone can reconstruct patient composition in a model. The purpose of this study was to examine whether the application of a modern analytics system utilizing 3D modeling technology in the development of a primary stem was successful in restoring patient biomechanics, specifically with regards to femoral offset (FO) and leg length discrepancy (LLD). Two hundred fifty six patients in a non-randomized, post-market multicenter study across 7 sites received a primary cementless fit and fill stem. Full anteroposterior pelvis and Lauenstein cross-table lateral x-rays were collected preoperatively and at 6-weeks postoperative. Radiographic parameters including contralateral and operative FO and LLD were measured. Preoperative and postoperative FO and LLD of the operative hip were compared to the normal, native hip. Clinical outcomes including the Harris Hip Score (HHS), Lower Extremity Activity Scale (LEAS), Short Form 12 (SF12), and EuroQol 5D Score (EQ-5D) were collected preoperatively, 6 weeks postoperatively, and at 1 year.INTRODUCTION
METHODS
A careful evaluation of new technologies such as robotic-arm assisted total knee arthroplasty (RATKA) is important to understand the reduction in variability among users. While there is data reviewing the use of RATKA, the data is typically presented for experienced TKA surgeons. Therefore, the purpose of this cadaveric study was to compare the variability for several surgical factors between RATKA and manual TKA (MTKA) for surgeons undergoing orthopaedic fellowship training. Two operating surgeons undergoing orthopaedic fellowship training, each prepared six cadaveric legs for cruciate retaining TKA, with MTKA on one side (3 knees) and RATKA on the other (3 knees). These surgeons were instructed to execute a full RATKA or MTKA procedure through trialing and achieve a balanced knee. The number of recuts and final poly thickness was intra-operatively recorded. After completion of bone cuts, the operating surgeons were asked if they would perform a cementless knee based on their perception of final bone cut quality as well as rank the amount of mental effort exerted for required surgical tasks. Two additional fellowship trained orthopaedic assessment surgeons, blinded to the method of preparation, each post-operatively graded the resultant bone cuts of the tibia and femur according to the perceived percentage of cut planarity (grade 1, <25%; grade 2, 25–50%; grade 3, 51–75%; and grade 4, >76%). The grade for medial and lateral tibial bone cuts was averaged and a Wilcoxon signed rank test was used for statistical comparisons. Assessment surgeons also determined whether the knee was balanced in flexion and extension. A balanced knee was defined as relatively equal medial and lateral gaps under relatively equal applied load.Introduction
Methods
