scholarly journals The Effect of Femoral Cutting Guide Design Improvements for Patient-Specific Instruments

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Oh-Ryong Kwon ◽  
Kyoung-Tak Kang ◽  
Juhyun Son ◽  
Yun-Jin Choi ◽  
Dong-Suk Suh ◽  
...  
Keyword(s):  
Motion Artifacts ◽  
Patient Specific ◽  
Bone Resection ◽  
Cutting Guide ◽  
Patient Specific Instruments ◽  
Mri Scans ◽  
Total Knee ◽  
Magnetic Resonance Imaging Mri ◽  
The Cost ◽  
Implant Alignment

Although the application of patient-specific instruments (PSI) for total knee arthroplasty (TKA) increases the cost of the surgical procedure, PSI may reduce operative time and improve implant alignment, which could reduce the number of revision surgeries. We report our experience with TKA using PSI techniques in 120 patients from March to December 2014. PSI for TKA were created from data provided by computed tomography (CT) scans or magnetic resonance imaging (MRI); which imaging technology is more reliable for the PSI technique remains unclear. In the first 20 patients, the accuracy of bone resection and PSI stability were compared between CT and MRI scans with presurgical results as a reference; MRI produced better results. In the second and third groups, each with 50 patients, the results of bone resection and stability were compared in MRI scans with respect to the quality of scanning due to motion artifacts and experienced know-how in PSI design, respectively. The optimized femoral cutting guide design for PSI showed the closest outcomes in bone resection and PSI stability with presurgical data. It is expected that this design could be a reasonable guideline in PSI.

scholarly journals The use of imageless navigation to quantify cutting error in total knee arthroplasty

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Ran Schwarzkopf ◽  
Morteza Meftah ◽  
Scott E. Marwin ◽  
Michelle A. Zabat ◽  
Jeffrey M. Muir ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Bone Resection ◽  
Cutting Guide ◽  
Imageless Navigation ◽  
Valgus Angle ◽  
Flexion Extension ◽  
Cutting Error ◽  
Total Knee ◽  
Implant Alignment ◽  
Resection Depth

Abstract Purpose Navigated total knee arthroplasty (TKA) improves implant alignment by providing feedback on resection parameters based on femoral and tibial cutting guide positions. However, saw blade thickness, deflection, and cutting guide motion may lead to final bone cuts differing from planned resections, potentially contributing to suboptimal component alignment. We used an imageless navigation device to intraoperatively quantify the magnitude of error between planned and actual resections, hypothesizing final bone cuts will differ from planned alignment. Materials and methods A retrospective study including 60 consecutive patients undergoing primary TKA using a novel imageless navigation device was conducted. Device measurements of resection parameters were obtained via attachment of optical trackers to femoral and tibial cutting guides prior to resection. Following resection, optical trackers were placed directly on the bone cut surface and measurements were recorded. Cutting guide and bone resection measurements of both femoral and tibial varus/valgus, femoral flexion, tibial slope angles, and both femoral and tibial medial and lateral resection depths were compared using a Student's t-test. Results Femoral cutting guide position differed from the actual cut by an average 0.6 ± 0.5° (p = 0.85) in the varus/valgus angle and 1.0 ± 1.0° (p = 0.003) in the flexion/extension angle. The difference between planned and actual cut measurements for medial and lateral femoral resection depth was 1.1 ± 1.1 mm (p = 0.32) and 1.2 ± 1.0 mm (p = 0.067), respectively. Planned cut measurements based on tibial guide position differed from the actual cut by an average of 0.9 ± 0.8° (p = 0.63) in the varus/valgus angle and 1.1 ± 1.0° (p = 0.95) in slope angle. Measurement of medial and lateral tibial resection depth differed by an average of 0.1 ± 1.8 mm (p = 0.78) and 0.2 ± 2.1 mm (p = 0.85), respectively. Conclusions Significant discrepancies between planned and actual femoral bone resection were demonstrated for flexion/extension angle, likely the result of cutting error. Our data highlights the importance of cut verification postresection to confirm planned resections are achieved, and suggests imageless navigation may be a source of feedback that would allow surgeons to intraoperatively adjust resections to achieve optimal implant alignment.

scholarly journals Surgeon Dominated Design Can Improve the Accuracy of Patient-specific Instruments in Kinematically Aligned TKA

2020 ◽  
Author(s):  
Zhiwei Wang ◽  
Liang Wen ◽  
Liang Zhang ◽  
Desi Ma ◽  
Xiang Dong ◽  
...  
Keyword(s):  
Joint Line ◽  
Patient Specific ◽  
Group 14 ◽  
Bone Resection ◽  
Patient Specific Instrumentation ◽  
Improve Accuracy ◽  
Before And After ◽  
Patient Specific Instruments ◽  
Total Knee ◽  
Line P

Abstract Precise bone resection is mandatory for kinematically aligned total knee arthroplasty（KA-TKA). Patient-specific instrumentation (PSI) has been applied to improve the accuracy of bone resection in TKA for many years. The purpose of this study was to investigate whether surgeons’ domination in PSI design can improve accuracy in KA-TKA. A total of 24 patients (24 knees) who underwent KA-TKA in our institution were assigned into engineer designed PSI group (10 knees) and surgeon designed PSI group (14 knees). The bone resection discrepancies of every key facets were used to evaluate the accuracy of PSI in bone resection, while the absolute differences of joint line orientation before and after surgery were used to evaluate the accuracy of PSI in joint line restoration. The overall discrepancy of bone resection was reduced by surgeon designed PSI compared to engineer designed PSI by 0.33mm (P<0.001). Surgeon designed PSI could reduce the outliers in terms of relative discrepancies in bone resection as well. Moreover, surgeon designed PSI could significantly improve the accuracy of PSI in the restoration of the joint line (p=0.01). This study indicate that the dominance of surgeons in both PSI design and subsequent surgical operation should be emphasized in efforts to improve the accuracy of PSI.

scholarly journals The Bony Resection Accuracy with Patient-Specific Instruments during Total Knee Arthroplasty: A Retrospective Case Series Study

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Liang Yuan ◽  
Bin Yang ◽  
Xiaohua Wang ◽  
Bin Sun ◽  
Ke Zhang ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Tibial Plateau ◽  
Femoral Condyle ◽  
Medial Femoral Condyle ◽  
Lateral Femoral Condyle ◽  
Patient Specific ◽  
Lateral Tibial Plateau ◽  
Bone Resection ◽  
Total Knee

Purpose. Bony resection is the primary step during total knee arthroplasty. The accuracy of bony resection was highly addressed because it was deemed to have a good relationship with mechanical line. Patient-specific instruments (PSI) were invented to copy the bony resection references from the preoperative surgical plan during a total knee arthroplasty (TKA); however, the accuracy still remains controversial. This study was aimed at finding out the accuracy of the bony resection during PSI-assisted TKA. Methods. Forty-two PSI-assisted TKAs (based on full-length leg CT images) were analyzed retrospectively. Resected bones of every patient were given a CT scan, and three-dimensional radiographs were reconstructed. The thickness of each bony resection was measured with the three-dimensional radiographs and recorded. The saw blade thickness (1.27 mm) was added to the measurements, and the results represented intraoperative bone resection thickness. A comparison between intraoperative bone resection thickness and preoperatively planned thickness was conducted. The differences were calculated, and the outliers were defined as >3 mm. Results. The distal femoral condyle had the most accurate bone cuts with the smallest difference (median, 1.0 mm at the distal medial femoral condyle and 0.8 mm at the distal lateral femoral condyle) and the least outliers (none at the distal medial femoral condyle and 1 (2.4%) at the distal lateral femoral condyle). The tibial plateau came in second (median difference, 0.8 mm at the medial tibial plateau and 1.4 mm at the lateral tibial plateau; outliers, none at the medial tibial plateau and 1 (2.6%) at the lateral tibial plateau). Regardless of whether the threshold was set to >2 mm (14 (17.9%) at the tibial plateau vs. 12 (14.6%) at the distal femoral condyle, p > 0.05 ) or >3 mm (1 (1.3%) at the tibial plateau vs. 1 (1.2%) at the distal femoral condyle, p > 0.05 ), the accuracy of tibial plateau osteotomy was similar to that of the distal femoral condyle. Osteotomy accuracy at the posterior femoral condyle and the anterior femoral condyle were the worst. Outliers were up to 6 (15.0%) at the posterior medial femoral condyle, 5 (12.2%) at the posterior lateral femoral condyle, and 6 (15.8%) at the anterior femoral condyle. The percentages of overcut and undercut tended to 50% in most parts except the lateral tibial plateau. At the lateral tibial plateau, the undercut percentage was twice that of the overcut. Conclusion. The tibial plateau and the distal femoral condyle share a similar accuracy of osteotomy with PSI. PSI have a generally good accuracy during the femur and tibia bone resection in TKA. PSI could be a kind of user-friendly tool which can simplify TKA with good accuracy. Level of Evidence. This is a Level IV case series with no comparison group.

Functional Outcomes and Accuracy of Patient-Specific Instruments for Total Knee Arthroplasty

2018 ◽  
Vol 25 (5) ◽  
pp. 470-475 ◽  
Author(s):  
Andrea H. Stone ◽  
Udai S. Sibia ◽  
James H. MacDonald
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Functional Outcomes ◽  
Patient Specific ◽  
Consecutive Series ◽  
Coronal Alignment ◽  
Patient Specific Instrumentation ◽  
Estimated Blood Loss ◽  
Patient Specific Instruments ◽  
Total Knee

Background. Patient-specific instruments (PSIs) were developed to improve mechanical axis alignment for patients undergoing total knee arthroplasty (TKA) as neutral alignment (180°) is a predictor of long-term success. This study examines alignment accuracy and functional outcomes of PSI as compared with standard instruments (SIs). Methods. We retrospectively reviewed a consecutive series of TKA procedures using PSI. A total of 85 PSI procedures were identified, and these were compared with a matched cohort of 85 TKAs using SI. Intraoperative decision-making, estimated blood loss, efficiency, Knee Society Scores, and postoperative radiographs were evaluated. Results. One hundred and seventy patients with comparable patient demographics were reviewed. Eighty-one percent of the PSI procedures were within target (180 ± 3°) mechanical alignment, while the SI group had 70% of cases within the target plane ( P = .132). Mean target alignment (2.0° PSI vs 2.2° SI, P = .477) was similar between groups. Twenty-seven percent of patients in the PSI group had surgeon-directed intraoperative recuts to improve the perceived coronal alignment. The change in hematocrit was reduced in the PSI group (8.89 vs 7.21, P = .000). Procedure time and total operating room time were equivalent. Knee Society Scores did not differ between groups at 6 months or at 1 year. Conclusion. Patient-specific instrumentation decreased change in hematocrit, though coronal alignment and efficiency were equivalent between groups. Surgeons must evaluate cuts intraoperatively to confirm alignment. Functional outcomes are equivalent for PSI and SI groups.

scholarly journals Accuracy of Coronal Plane Mechanical Alignment in a Customized, Individually Made Total Knee Replacement with Patient-Specific Instrumentation

2017 ◽  
Vol 31 (08) ◽  
pp. 792-796 ◽  
Author(s):  
Gary Levengood ◽  
Jack Dupee
Keyword(s):  
Mechanical Axis ◽  
Computer Assisted Surgery ◽  
Coronal Plane ◽  
Patient Specific ◽  
Computer Assisted ◽  
Consecutive Series ◽  
Mechanical Alignment ◽  
Patient Specific Instrumentation ◽  
Patient Specific Instruments ◽  
Total Knee

AbstractThe objective of this study was to evaluate the accuracy of a customized individually made total knee implant used in conjunction with patient-specific cutting guides in restoring coronal plane mechanical axis alignment using computer-assisted surgery (CAS). A consecutive series of 63 total knee arthroplasty (TKA) patients were prospectively measured with intraoperative CAS. The patient-specific instruments and implants were created utilizing a preoperative CT scan. CAS system was used for all patients, to determine mechanical alignment. Bone cuts were made using the patient-specific instruments. Both bone cuts and final coronal mechanical alignment were recorded utilizing the navigation system for the assessment.The patient-specific instruments and implants provided perfect neutral coronal mechanical alignment (0°) in 53 patients. The remaining 10 patients had a postoperative alignment within ± 2° of neutral. The average preoperative deformity was 5.57° versus 0.18° postoperatively (p < 0.0001). The mean correction angle was 5.68°. No patients had postoperative extension deficits as measured with CAS (7.50° pre-op for 40/63 patients). Customized, individually made total knee implant with patient-specific cutting jigs showed results that are comparable to those of CAS systems in this study. This technology restores the neutral coronal mechanical axis very accurately, while offering unique benefits such as improved implant fit and restoration of the patient's J-curves, which require further investigation.

Total knee arthroplasty with patient-specific instruments improves function and restores limb alignment in patients with extra-articular deformity

The Knee ◽  
2013 ◽  
Vol 20 (6) ◽  
pp. 407-411 ◽  
Author(s):  
Emmanuel Thienpont ◽  
Frederic Paternostre ◽  
Martin Pietsch ◽  
Mahmoud Hafez ◽  
Stephen Howell
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Patient Specific ◽  
Limb Alignment ◽  
Patient Specific Instruments ◽  
Total Knee
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