scholarly journals Posterior condylar offset ratio more precisely reconstructed with robotic arm-assisted total knee arthroplasty when compared to conventional manual technique

2020 ◽  
Vol 8 (5_suppl4) ◽  
pp. 2325967120S0032
Author(s):  
Lars-René Tücking ◽  
Peter Savov ◽  
Henning Windhagen ◽  
Max Ettinger
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Weight Bearing ◽  
Primary Objective ◽  
Robotic Arm ◽  
Relative Deviation ◽  
Posterior Condylar Offset ◽  
Tibial Insert ◽  
Posterior Condylar ◽  
Total Knee

Aims and Objectives: The use of robotic-arm assisted total knee arthroplasty promises more precision in TKA implant technique. Precise implantation is elemental in improving functional and radiological outcome after TKA. The posterior condylar offset ratio (PCOR) is one important radiological parameter in total knee arthroplasty (TKA). The PCOR correlates with the maximum range-of-motion of the knee. A decrease of PCOR in TKA could lead to early impingement of the tibial insert with a consecutive decreased flexion range of the knee. The primary objective of this study was to determine differences in PCOR reconstruction after TKA between manual and robotic arm-assisted TKA surgery. Materials and Methods: A total of 80 patients undergoing primary TKA performed by one single senior surgeon were included in this prospective study. Two groups (Robotic arm-assisted TKA group, manual TKA group, n=40 patients each) were compared on the basis of hip-knee-ankle angle (HKA), medial proximal tibial angle (mPTA), distal lateral femoral angle (dLFA) and PCOR. Weight-bearing full-leg a.p. radiographs, as well as lateral knee radiographs, were performed pre- and postoperatively. All surgeries were performed with one single posterior stabilized TKA prosthesis type. Statistics consisted of parametric t-testing with a level of significance of p<0.05. Results: Preoperative limb alignment, mPTA and dLFA did not differ in between groups (each p>0.05). Postoperative mean PCOR was larger in the robotic arm-assisted TKA group (0.51 ± 0.05 vs. manual TKA group 0.47 ± 0.05, p=0.006). The absolute mean difference of pre- and postoperative PCOR was higher in the manual TKA group when compared to the robotic arm-assisted TKA group (-0.059 vs. -0.017, p=0.001). Manual TKA group showed a mean relative deviation of 12,03% (± 9,1%) in pre- to postoperative PCOR, whereas a mean relative deviation of 3.9 % (± 4.5%) was found in the robotic arm-assisted TKA group. Conclusion: Robotic arm-assisted TKA showed higher precision regarding postoperative PCOR with lower absolute mean differences and less relative deviation in pre- and postoperative PCOR when compared to manual TKA. A precise reconstruction of PCOR correlates with a better functional outcome as shown in previous studies before.

Does Posterior Condylar Offset Affect Clinical Results following Total Knee Arthroplasty?

2017 ◽  
Vol 31 (08) ◽  
pp. 754-760 ◽  
Author(s):  
Ryan Degen ◽  
Jacob Matz ◽  
Matthew Teeter ◽  
Brent Lanting ◽  
James Howard ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Outcome Measures ◽  
Knee Arthroplasty ◽  
Short Form ◽  
Clinical Results ◽  
Patient Reported Outcome Measures ◽  
Posterior Condylar Offset ◽  
Patient Reported ◽  
Posterior Condylar ◽  
Total Knee

AbstractTotal knee arthroplasty (TKA) is an effective, durable treatment for knee osteoarthritis. However, a subset of patients experiences incomplete pain relief and ongoing dysfunction. Posterior condylar offset (PCO) has previously been shown to be associated with postoperative range of motion (ROM) following TKA; however, an association with patient-reported outcome measures (PROMs) has not been established. The purpose of this study was to evaluate the association between PCO and postoperative ROM and PROMs. A retrospective review of 970 posterior-stabilized single design TKAs was performed. Preoperative and postoperative radiographs were analyzed to measure the change in PCO and anteroposterior (AP) femoral dimension. Clinical outcome measures, including Short Form-12 physical and mental component summaries, Western Ontario and McMaster Universities Arthritis Index, and Knee Society Score were reviewed to determine if these were influenced by changes in PCO and AP dimension. PCO was increased by more than 3 mm in 15.1%, maintained (within 3 mm) in 59.6%, and decreased by more than 3 mm in 25.3% of patients. Comparing between these groups, there were no significant differences in postoperative ROM or PROM. AP dimension increased in 24.4%, maintained in 47.8%, and decreased in 27.8%. Similarly, there were no significant differences in ROM or PROM between these groups. Spearman's correlation analyses failed to identify an association between PCO and ROM or PROMs. In conclusion, increasing or decreasing PCO or AP femoral dimension with this PS TKA design did not significantly affect postoperative ROM or PROM. Similarly, maintenance of PCO within one implant size with this system compared with optimal sizing had no deleterious effect on TKA outcomes.

scholarly journals A computational simulation study to determine the biomechanical influence of posterior condylar offset and tibial slope in cruciate retaining total knee arthroplasty

2018 ◽  
Vol 7 (1) ◽  
pp. 69-78 ◽  
Author(s):  
K-T. Kang ◽  
Y-G. Koh ◽  
J. Son ◽  
O-R. Kwon ◽  
J-S. Lee ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Patellar Tendon ◽  
Contact Stress ◽  
Knee Arthroplasty ◽  
Computational Simulation ◽  
Tibial Slope ◽  
Cruciate Retaining ◽  
Posterior Condylar Offset ◽  
Posterior Condylar ◽  
Total Knee

ObjectivesPosterior condylar offset (PCO) and posterior tibial slope (PTS) are critical factors in total knee arthroplasty (TKA). A computational simulation was performed to evaluate the biomechanical effect of PCO and PTS on cruciate retaining TKA.MethodsWe generated a subject-specific computational model followed by the development of ± 1 mm, ± 2 mm and ± 3 mm PCO models in the posterior direction, and -3°, 0°, 3° and 6° PTS models with each of the PCO models. Using a validated finite element (FE) model, we investigated the influence of the changes in PCO and PTS on the contact stress in the patellar button and the forces on the posterior cruciate ligament (PCL), patellar tendon and quadriceps muscles under the deep knee-bend loading conditions.ResultsContact stress on the patellar button increased and decreased as PCO translated to the anterior and posterior directions, respectively. In addition, contact stress on the patellar button decreased as PTS increased. These trends were consistent in the FE models with altered PCO. Higher quadriceps muscle and patellar tendon force are required as PCO translated in the anterior direction with an equivalent flexion angle. However, as PTS increased, quadriceps muscle and patellar tendon force reduced in each PCO condition. The forces exerted on the PCL increased as PCO translated to the posterior direction and decreased as PTS increased.ConclusionThe change in PCO alternatively provided positive and negative biomechanical effects, but it led to a reduction in a negative biomechanical effect as PTS increased. Cite this article: K-T. Kang, Y-G. Koh, J. Son, O-R. Kwon, J-S. Lee, S. K. Kwon. A computational simulation study to determine the biomechanical influence of posterior condylar offset and tibial slope in cruciate retaining total knee arthroplasty. Bone Joint Res 2018;7:69–78. DOI: 10.1302/2046-3758.71.BJR-2017-0143.R1.

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