@article{ArnholdtKamawalHorasetal.2020,
  author    = {Arnholdt, J{\"o}rg and Kamawal, Yama and Horas, Konstantin and Holzapfel, Boris M. and Gilbert, Fabian and Ripp, Axel and Rudert, Maximilian and Steinert, Andre F.},
  title     = {Accurate implant fit and leg alignment after cruciate-retaining patient-specific total knee arthroplasty},
  series = {BMC Musculoskeletal Disorders},
  volume    = {21},
  journal   = {BMC Musculoskeletal Disorders},
  doi       = {10.1186/s12891-020-03707-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-230012},
  year      = {2020},
  abstract  = {Background For improved outcomes in total knee arthroplasty (TKA) correct implant fitting and positioning are crucial. In order to facilitate a best possible implant fitting and positioning patient-specific systems have been developed. However, whether or not these systems allow for better implant fitting and positioning has yet to be elucidated. For this reason, the aim was to analyse the novel patient-specific cruciate retaining knee replacement system iTotal (TM) CR G2 that utilizes custom-made implants and instruments for its ability to facilitate accurate implant fitting and positioning including correction of the hip-knee-ankle angle (HKA). Methods We assessed radiographic results of 106 patients who were treated with the second generation of a patient-specific cruciate retaining knee arthroplasty using iTotal\(^{TM}\) CR G2 (ConforMIS Inc.) for tricompartmental knee osteoarthritis (OA) using custom-made implants and instruments. The implant fit and positioning as well as the correction of the mechanical axis (hip-knee-ankle angle, HKA) and restoration of the joint line were determined using pre- and postoperative radiographic analyses. Results On average, HKA was corrected from 174.4 degrees +/- 4.6 degrees preoperatively to 178.8 degrees +/- 2.2 degrees postoperatively and the coronal femoro-tibial angle was adjusted on average 4.4 degrees. The measured preoperative tibial slope was 5.3 degrees +/- 2.2 degrees (mean +/- SD) and the average postoperative tibial slope was 4.7 degrees +/- 1.1 degrees on lateral views. The joint line was well preserved with an average modified Insall-Salvati index of 1.66 +/- 0.16 pre- and 1.67 +/- 0.16 postoperatively. The overall accuracy of fit of implant components was decent with a measured medial overhang of more than 1 mm (1.33 mm +/- 0.32 mm) in 4 cases only. Further, a lateral overhang of more than 1 mm (1.8 mm +/- 0.63) (measured in the anterior-posterior radiographs) was observed in 11 cases, with none of the 106 patients showing femoral notching. Conclusion The patient-specific iTotal\(^{TM}\) CR G2 total knee replacement system facilitated a proper fitting and positioning of the implant components. Moreover, a good restoration of the leg axis towards neutral alignment was achieved as planned. Nonetheless, further clinical follow-up studies are necessary to validate our findings and to determine the long-term impact of using this patient- specific system.},
  language  = {en}
}
@article{ArnholdtGilbertBlanketal.2017,
  author    = {Arnholdt, J{\"o}rg and Gilbert, Fabian and Blank, Marc and Papazoglou, Jannis and Rudert, Maximilian and N{\"o}th, Ulrich and Steinert, Andre F.},
  title     = {The Mayo conservative hip: complication analysis and management of the first 41 cases performed at a University level 1 department},
  series = {BMC Muskoskeletal Disorders},
  volume    = {18},
  journal   = {BMC Muskoskeletal Disorders},
  number    = {250},
  doi       = {10.1186/s12891-017-1613-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-157812},
  year      = {2017},
  abstract  = {Background: To prevent bone loss in hip arthroplasty, several short stem systems have been developed, including the Mayo conservative hip system. While there is a plethora of data confirming inherent advantages of these systems, only little is known about potential complications, especially when surgeons start to use these systems. Methods: In this study, we present a retrospective analysis of the patients' outcome, complications and the complication management of the first 41 Mayo conservative hips performed in 37 patients. For this reason, functional scores, radiographic analyses, peri- and postoperative complications were assessed at an average follow-up of 35 months. Results: The overall HHS improved from 61.2 pre-operatively to 85.6 post-operatively. The German Extra Short Musculoskeletal Function Assessment Questionnaire (XSFMA-D) improved from 30.3 pre-operatively to 12.2 post-operatively. The most common complication was an intraoperative non-displaced fracture of the proximal femur observed in 5 cases (12.1\%). Diabetes, higher BMI and older ages were shown to be risk factors for these intra-operative periprosthetic fractures (p < 0.01). Radiographic analysis revealed a good offset reconstruction in all cases. Conclusion: In our series, a high complication rate with 12.1\% of non-displaced proximal femoral fractures was observed using the Mayo conservative hip. This may be attributed to the flat learning curve of the system or the inherent patient characteristics of the presented cohort."},
  language  = {en}
}