OMNIBotics Clinical Results

OMNIBotics Clinical Results

  BACK: Intellegent Instrumentation

NEXT: OMNIBotics Virtual Surgery 


Robotic-Assisted Total Knee Replacement: A Surgical Technique Video


J.A. Koenig: Bone & Joint 2016 vol. 98-B SUPP 8 115

Abstract:Insall, Laskin and others have taught us that the goal of successful total knee replacement (TKR) is to have well fixed and fitted components in a neutral mechanical axis (MA) with balanced soft tissues. Computer and robotic assisted (C-RAS) TKR with real time validation is an excellent tool to help you to attain these goals. Ritter and others have shown higher early failure rates with TKR's where the final alignment is outside a 3-degree window of the neutral MA. Dalury and Schroer have each shown higher early failure rates in TKR's with postoperative instability and or malalignment. C-RAS TKR helps prevent and significantly lowers the number of TKR outliers that may go on to early aseptic loosening and failure as compared with traditional methods.

This featured video was created to show how surgeons can benefit from real-time validation and the kinematic data provided during C-RAS. The system helps in their intraoperative decision-making process and then guides them to make precise bone cuts and balance the soft tissue envelope in a very time efficient and highly repeatable fashion. Additionally, imageless C-RAS breaks away from the paradigm of pre-operative MRI or CT scan imaging studies by no longer requiring such costly procedures. This relatively easy, simple to learn, and cost-efficient procedure is a valuable asset in the operating room, for both the surgeon and patient. Furthermore, it is highly customizable and easily integrated into any surgeon's workflow, technique, and exposure. The viewer will learn the C-RAS TKR simple workflow of Tracking, Registration, Navigation, and Validation.

The results of the previously published abstract “Influence of Pre-Operative Deformity on Surgical Accuracy and Time in Robotic-Assisted TKA” JA Koenig; C Plaskos; 95-B/SUPP28/62 2013, will also be presented at the end of the video. Finally many have argued that C-RAS TKR is an excellent method to teach the “ART of TKR” to young surgeons, residents and students as they can see with real time validation and data the immediate consequences and effects of their intra-operative actions and maneuvers.

"Influence of Pre-Operative Deformity on Surgical Accuracy in and Time in Robotic-Assisted TKA"

J.A. Koenig, C. Plaskos: The Bone + Joint J 2013 vol. 95-B no SUPP 28 62

Introduction: We evaluated the utility of imageless computer-navigation coupled with a miniature robotic-cutting guide for managing large deformities in TKA. We asked what effect did severe pre-operative deformities have on post-operative alignment and surgery time using the system. We also report on the early functional outcomes of this group of patients.

Conclusions: We have shown that in one surgeon's hands severe coronal deformities and flexion contractures can be consistently corrected to within 3° and 4° of neutral, respectively, when using computer navigation. The additional time required for managing these more difficult cases using this technology was typically 3–5 minutes.

Press-fit Total Knee Arthroplasty with a Robotic-Cutting Guide: Proof of Concept and Initial Clinical Experience

C.E Ponder, C. Plaskos, E.J. Cheal: Bone Joint J 2013 vol. 95-B no. SUPP 28 61

Introduction: Intimate bone-implant contact is a requirement for achieving stable component fixation and osseo-integration of porous-coated implants in TKA. However, consistently attaining a press-fit and a tight-fitting femoral component can be problematic when using conventional instrumentation. We present a new robotic cutting-guide system that permits intra-operative adjustment of the femoral resections such that a specified amount of press-fit can be consistently atttained. 

Conclusions: A.R.T. (APEX Robotic Technology™) saw guide positioning precision was found to be sub-degree and sub-millimetric, allowing for significantly more accurate and repeatable bone resections than conventional instrumentation.


"Robotic versus Computer-Assisted Navigation in Total Knee Arthroplasty: Efficiency and Accuracy"

T.C. Clark, F.H. Schmidt: ISRN Orthopedics vol. 2013, Article IS 794827

Introduction: Since the introduction of robot-assisted navigation in primary total knee arthroplasty (TKA), there has been little research conducted examining the efficiency and accuracy of the system compared to computer-assisted navigation systems. This was a retrospective study consisting of 52 patients who underwent primary TKA utilizing RAN (robotic-assisted navigation) and 29 patients utilizing CAN (computer-assisted navigation).The primary outcome measure was navigation time. Secondary outcome measures included intraoperative final mechanical axis alignment, intraoperative robot-assisted bone cut accuracy, tourniquet time, and hospitalization length.

Conclusions: Among patients undergoing TKA, there was decreased navigation time, decreased final malalignment, and decreased hospitalization length associated with the use of RAN when compared to CAN independent of age, BMI, and prereplacement alignment.


"Patient Specific Instrumentation versus Computer Navigated, Adjustable Cutting Blocks in Total Knee Arthroplasty"

D. Nam, MD; P. Maher, BS; B.J. Rebolledo, MD; A. S. McLawhorn, MD; A.D. Pearle, MD: AAOS 2013 Poster Presentation

Introduction: Computer-assisted surgical (CAS) techniques improve component and overall alignment in total knee arthroplasty (TKA)1. Recently, patient specific instrumentation (PSI) has been introduced, in which preoperative 3-D imaging is used to manufacture disposable cutting blocks specific to a patient’s anatomy. Proposed benefits include improvements in component alignment and cost-efficiency versus conventional techniques, although the reported results of these benefits are mixed2,3.

Objective: To compare the alignment accuracy of PSI to an imageless, CAS system performed with adjustable cutting blocks, in total knee arthroplasty.

Hypothesis: PSI will not achieve the same degree of overall mechanical, and component alignment accuracy as the CAS system. 

Conclusions: MRI-based, patient specific instrumentation does not provide the same degree of alignment accuracy as an imageless, CAS system in TKA. While PSI may potentially increase the cost-effectiveness of TKA, its use does not result in the same degree of alignment accuracy as CAS techniques.

1. Mason JB et al. Meta-analysis of alignment outcomes in computer-assisted total knee arthroplasty surgery. J Arthroplasty, 2007;22(8):1097-1106
2. Ng VY et al. Improved accuracy of alignment with patient-specific positioning guides compared with manual instrumentation in TKA. Clin Orthop Relat Res. 2011.
3. Nunley RM et al. Are patient-specific cutting blocks cost-effective for total knee arthroplasty? Clin Orthop Relat Res. 2012;;470(3):889-894.


Surgical Accuracy and Efficiency of Computer-Navigated TKA with a Robotic Cutting Guide - Report on First 100 Cases

J.A. Koenig, E.M. Suero, C. Plaskos: J Bone Joint Surg Br 2012 vol 94-B no. SUPP XLIV 301

Introduction: Robotic-guided arthroplasty procedures are becoming increasingly common. We introduced a new computer-navigated TKA system with a robotic cutting guide into a community-based hospital and characterized the accuracy and efficiency of the technique. We retrospectively reviewed our first 100 cases following IRB approval. Tourniquet time, intraoperative bone cut accuracy and final limb alignment as measured by the computer were collected and divided into consecutive quartiles: Groups I, II, III, and IV; 25 cases per group. All resections were planned neutral to the mechanical axis. Postoperative component alignment and overall mechanical axis limb alignment were also measured on standing long-leg radio graphs by two independent observers at minimum six weeks follow-up. Radiographic alignment was available for 62 cases.

Conclusions: Imageless computer-navigated TKA with a robotic cutting guide allowed one surgeon to make bone resections within 3° of neutral in 98% of cases. Radiographic limb alignment was less precise, which is consistent with the known limitations inherent to this measurement technique. Surgeons can expect this procedure to take 15 additional minutes during the first ten cases and five additional minutes during the second ten cases on average, without compromising accuracy.


"Adjustable Cutting Blocks Improve Alignment and Surgical Time in Computer-assisted Total Knee Replacement"

E.M. Suero, C. Plaskos, P.L. Dixon, A.D. Pearle: Knee Surg Sports Traumatol Arthrosc. 2012 Sep; 20(9): 1736-41

Introduction: Computer navigation increases accuracy and precision of component alignment in total knee arthroplasty (TKA) compared to the manual technique, but is often associated with increases in surgical time. In a previous cadaver study, we demonstrated a significant improvement in guide positioning precision, final bone cut precision, and procedure length when using adjustable cutting blocks (ACB) compared to conventional cutting blocks (CCB) in computer-navigated TKA. The aim of this study was to evaluate the use of ACB in vivo.

Conclusion: ACB for TKA significantly reduced postoperative mechanical alignment variability and tourniquet time compared to conventional navigated instrumentation, while providing equal or better component alignment.


"Sequential Versus Automated Cutting Guides in Computer-Assisted Total Knee Arthroplasty"


D. Koulalis, P.F. O'Loughlin, C. Plaskos, D. Kendoff, M. Cross, A. Pearle: The Knee 18 (2011) 436-442

Abstract:  The accuracy and efficiency of automated cutting guides in CAS systems have not been previously compared with conventional CAS techniques. Therefore, it is not yet clear if these more advanced technologies are warranted. We hypothesized that a novel automated cutting guide with CAS for total knee arthroplasty would be more efficient and more accurate than conventional navigation with sequential cutting blocks. Twelve cadaver legs were used in total. Each leg was randomly assigned to either an automated guide positioning or a conventional freehand computer-navigated guide positioning. The guide positions postosseous fixation and the final bone-cut surfaces were digitized and compared to the targeted cutting planes. The final location of the impacted trial implant was also digitized and compared to the planned implant location. The time for each step and the total time taken to prepare the femur were measured for both groups. The mean femoral preparation time was shorter with the automated cutting guide than the conventional method (5.5 min versus 13.8 min, pb0.001). The average deviation in the final bone resections from the planned resections was significantly lower for the automated cutting guide in the frontal/rotational plane (0.55° versus 1.1°), sagittal plane (0.75° versus 2.0°), and cut height direction (0.56 mm versus 1.6 mm). Therefore, based on these results, we concluded that automated cutting-guide positioning resulted in more efficient and more accurate femoral cuts in comparison to the conventional navigation method in a cadaveric model.


  • C. Plaskos is an employee of OMNIlife science, Inc.
  • E.J. Cheal is an employee of OMNIlife science, Inc.
  • J.A. Koenig is a paid consultant for OMNIlife science, Inc.
  • F.H. Schmidt is a paid consultant for OMNIlife science, Inc.
  • C.E. Ponder is a paid consultant for OMNIlife science, Inc.
OMNIBotics Clinical Results
OMNINAV, OMNIPlasty, OMNI, TKR, THA, BoneMorphing, ART software, CAS, Robotic Knee Surgery, Navigated Surgery
OMNINAV systems have been designed and tested to provide the best possible patient outcomes in joint reconstruction.