Conventionally instrumented inverse kinematic alignment for total knee arthroplasty: How is it done?

Purpose: For primary total knee arthroplasty (TKA), there is an increasing trend towards patient-specific alignment strategies such as kinematic alignment (KA) and inverse kinematic alignment (iKA), which by restoring native joint mechanics may yield higher patient satisfaction rates. Second, the most recent Australian joint registry report describes favourable revision rates for conventionally instrumented TKA compared to technology-assisted techniques such as those using navigation, robotics or custom-cutting blocks. The aim of this technique article is to describe in detail a surgical technique for TKA that: (1) utilises the principles of iKA and (2) uses conventionally instrumented guided resections thereby avoiding the use of navigation, robotics or custom blocks. Methods: A TKA technique is described, whereby inverse kinematic principles are utilised and patient-specific alignment is achieved. Additionally, the patellofemoral compartment of the knee is restored to the native patellofemoral joint line. The sequenced technical note provided may be utilised for cemented or cementless components; cruciate retaining or sacrificing designs and for fixed or rotating platforms. Results: An uncomplicated, robust and reproducible technique for TKA is described. Discussion: Knee arthroplasty surgeons may wish to harness the emerging benefits of both a conventionally instrumented technique and a patient-specific alignment strategy. Level of Evidence: Level V.

Evaluation of the Impact of Different Instrumentation Techniques on the Incidence of Postoperative Pain in Patients Undergoing Root Canal Treatment.

BACKGROUND: Postoperative pain is a common concern in root canal treatment, and the choice of instrumentation technique can significantly impact patient comfort. This study aimed to evaluate the impact of different instrumentation techniques on the incidence of postoperative pain in patients undergoing root canal treatment. METHODS: A randomized controlled trial was conducted on 208 patients randomly assigned to four groups: step-back preparation, crown-down preparation, hybrid technique, and conventional instrumentation. Pain intensity was assessed using a verbal rating scale (VRS) at six, 12, 24, 48, and 72 hours postoperatively. Data were analyzed using appropriate statistical methods. RESULTS: The mean pain scores and standard deviations (SDs) were calculated for each instrumentation technique at different time intervals. At six hours, the step-back preparation group reported a mean pain score of 2.3 (SD = 0.8), the crown-down preparation group had a score of 2.8 (SD = 0.9), the hybrid technique group had a score of 2.5 (SD = 0.7), and the conventional instrumentation group had a score of 3.1 (SD = 0.1). The differences in pain scores between the groups were statistically significant at all time intervals (p < 0.05). CONCLUSION: The choice of instrumentation technique significantly influenced the incidence of postoperative pain in root canal treatment. The step-back preparation technique was associated with lower pain intensity than the crown-down preparation, hybrid technique, and conventional instrumentation. These findings highlight the importance of considering the instrumentation technique to optimize patient comfort during and after root canal treatment.

Learning curve of the 67 steps of conventional total knee replacement: an experimental study.

The instrumentation system for total knee replacement (TKR) has been there since the 1970s. The many steps and instruments are the main features despite several modifications over the last 50 years. This may lead to the accumulation of errors as certain steps are dependent on others. This study aimed to identify the errors while performing TKR by three trainees at different levels of training. Methods: Three trainees with different expertise performed the steps of TKR on bone models. One senior supervisor recorded the outcomes, including operative time and errors made during the experiment. Errors were further categorized into correctable and uncorrectable ones. Results: Most of the errors were made by the trainee with the least experience during the stages of femoral cutting, sizing, and rotation. The first-year resident has taken 1.25 times longer than the fellow in preparing the femur and 1.11 times in preparing the tibia. The recorded mistakes were 28, 8, and 3 for the first-year resident, the second-year resident, and the fellow surgeon, respectively. Fifteen of the mistakes were uncorrectable, and none of them were from the senior surgeon. Conclusion: The results of this study highlight the type of errors made by different trainees. This shows the steep learning curve of conventional instrumentation systems for trainees. Increasing cognitive skills and applying computer-assisted technologies may help trainees overcome this steep learning curve.

Restoring tibial obliquity for kinematic alignment in total knee arthroplasty: conventional versus patient-specific instrumentation.

INTRODUCTION: In total knee arthroplasty (TKA), tibial obliquity-restoration using kinematic alignment (KA) poses a major difference to conventional mechanical alignment. This study aimed at analysing the accuracy of conventional instrumentation (CI) versus patient-specific instrumentation (PSI) to restore anatomic tibial obliquity measured by the medial proximal tibial angle (MPTA) on conventional X-rays. MATERIALS AND METHODS: One-hundred patients were randomized to receive CI (n = 50) or PSI (n = 50) for TKA. Further 100 patients received CI without randomisation, resulting in 200 patients in total (127 women, mean age: 70.7 (range: 48-90 years). Pre- and postoperative X-rays were measured twice by two observers with a 2-week break in-between. Inter- and intraclass correlations were calculated and postoperative tibial obliquity compared to preoperative anatomy. RESULTS: In 150 patients with CI, no case with tibial obliquity-deviation greater than 2° was found, whilst 21.3% (n = 32) and 0.7% (n = 1) of cases and had a deviation of 0°-1°, and 1°-2°, respectively. In the remaining 78.0% (n = 117), tibial obliquity was restored. In 50 patients with PSI, no single case with a deviation greater than 1° was found. Sixty percent (n = 30) had a deviation of 0°-1°. In the remaining 40.0% (n = 20), no deviation from preoperative measurements was found. Consequently, CI resulted in a significantly smaller change in tibial obliquity from preoperative to postoperative than PSI (p < 0.001). Inter- and intra-class correlations showed a substantial agreement (any ICC > 0.90). CONCLUSION: Both conventional and patient-specific instrumentation revealed adequate results with respect to restoring tibial obliquity in kinematically aligned TKA, with conventional instrumentation achieving superior results.

Image-Free Robotic-Assisted Total Knee Arthroplasty Improves Implant Alignment Accuracy: A Cadaveric Study.

BACKGROUND: Improving resection accuracy and eliminating outliers in total knee arthroplasty (TKA) is important to improving patient outcomes regardless of alignment philosophy. Robotic-assisted surgical systems improve resection accuracy and reproducibility compared to conventional instrumentation. Some systems require preoperative imaging while others rely on intraoperative anatomic landmarks. We hypothesized that the alignment accuracy of a novel image-free robotic-assisted surgical system would be equivalent or better than conventional instrumentation with fewer outliers. METHODS: Forty cadaveric specimens were used in this study. Five orthopedic surgeons performed 8 bilateral TKAs each, using the VELYS Robotic-Assisted System (DePuy Synthes) and conventional instrumentation on contralateral knees. Pre-resection and postresection computed tomography scans, along with optical scans of the implant positions were performed to quantify resection accuracies relative to the alignment targets recorded intraoperatively. RESULTS: The robotic-assisted cohort demonstrated smaller resection errors compared to conventional instrumentation in femoral coronal alignment (0.63° ± 0.50° vs 1.39° ± 0.95°, P < .001), femoral sagittal alignment (1.21° ± 0.90° vs 3.27° ± 2.51°, P < .001), and tibial coronal alignment (0.93° ± 0.72° vs 1.65° ± 1.29°, P = .001). All other resection angle accuracies were equivalent. Similar improvements were found in the femoral implant coronal alignment (0.89° ± 0.82° vs 1.42° ± 1.15°, P = .011), femoral implant sagittal alignment (1.51° ± 1.08° vs 2.49° ± 2.10°, P = .006), and tibial implant coronal alignment (1.31° ± 0.84° vs 2.03° ± 1.44°, P = .004). The robotic-assisted cohort had fewer outliers (errors >3°) for all angular resection alignments. CONCLUSION: This in vitro study demonstrated that image-free robotic-assisted TKA can improve alignment accuracy compared to conventional instrumentation and reduce the incidence of outliers.

Improved accuracy and reproducibility of a novel CT-free robotic surgical assistant for medial unicompartmental knee arthroplasty compared to conventional instrumentation: a cadaveric study.

PURPOSE: Alignment errors in medial unicompartmental knee arthroplasty (UKA) predispose to premature implant loosening and polyethylene wear. The purpose of this study was to determine whether a novel CT-free robotic surgical assistant improves the accuracy and reproducibility of bone resections in UKA compared to conventional manual instrumentation. METHODS: Sixty matched cadaveric limbs received medial UKA with either the ROSA® Partial Knee System or conventional instrumentation. Fifteen board-certified orthopaedic surgeons with no prior experience with this robotic application performed the procedures with the same implant system. Bone resection angles in the coronal, sagittal and transverse planes were determined using optical navigation while resection depth was obtained using calliper measurements. Group comparison was performed using Student's t test (mean absolute error), F test (variance) and Fisher's exact test (% within a value), with significance at p < 0.05. RESULTS: Compared to conventional instrumentation, the accuracy of bone resections with CT-free robotic assistance was significantly improved for all bone resection parameters (p < 0.05), other than distal femoral resection depth, which did not differ significantly. Moreover, the variance was significantly lower (i.e. fewer chances of outliers) for five of seven parameters in the robotic group (p < 0.05). All values in the robotic group had a higher percentage of cases within 2° and 3° of the intraoperative plan. No re-cuts of the proximal tibia were required in the robotic group compared with 40% of cases in the conventional group. CONCLUSION: The ROSA® Partial Knee System was significantly more accurate, with fewer outliers, compared to conventional instrumentation. The data reported in our current study are comparable to other semiautonomous robotic devices and support the use of this robotic technology for medial UKA. LEVEL OF EVIDENCE: Cadaveric study, Level V.

Better accuracy and reproducibility of a new robotically-assisted system for total knee arthroplasty compared to conventional instrumentation: a cadaveric study.

PURPOSE: Robotically-assisted total knee arthroplasty (TKA) has been shown to improve alignment and decrease outliers, an important goal in TKA procedures. The purpose of this cadaveric study was to compare the accuracy and reproducibility of a recently introduced TKA robotic system to conventional instrumentation for bone resections. METHODS: This cadaveric study compared 14 robotically-assisted TKA with 20 conventional TKAs. Four board-certified high volume arthroplasty surgeons with no prior experience in robotics (except one) performed the procedures with three different implant systems. Angle and level of bone resections obtained from optical navigation or calliper measurements were compared to the intra-operative plan to determine accuracy. Group comparison was performed using Student t test (mean) and F test (variance), with significance at p < 0.05. RESULTS: The robotic group demonstrated statistically more accurate results (p < 0.05) and fewer outliers (p < 0.05) than conventional instrumentation when aiming for neutral alignment. Final limb alignment (HKA) had an accuracy of 0.8° ± 0.6° vs 2.0° ± 1.6°, with 100% vs 75% of cases within 3° and 93% vs 60% within 2°. For the robotically-assisted knees, the accuracy of bone resection angles was below 0.6° with standard deviations below 0.4°, except for the femur flexion (1.3° ± 1.0°), and below 0.7 mm with standard deviations below 0.7 mm for bone resection levels. CONCLUSION: This in vitro study has demonstrated that this novel TKA robotic system produces more accurate and more reproducible bone resections than conventional instrumentation. It supports the clinical use of this new robotic system. LEVEL OF EVIDENCE: Cadaveric study, Level V.

Patient-specific instrumentation does not improve tibial component coronal alignment for medial UKA compared to conventional instrumentation.

BACKGROUND: Patient-specific instrumentation (PSI) may potentially improve unicompartmental knee arthroplasty (UKA) implant positioning and alignment. The purpose of this study was to compare early radiographic coronal alignment of medial UKA performed using PSI versus conventional instrumentation (CI) for tibial resections. METHODS: A consecutive series of 47 knees (47 patients) received medial UKA, with the tibial resections performed using CI (first 22 knees) or PSI (next 25 knees), while femoral resections were performed with CI in both groups. The target mechanical medial proximal tibial angle (mMPTA) was 87° ± 3°, and the target hip-knee-ankle (HKA) angle was 177° ± 2°. The postoperative mMPTA and HKA were evaluated from postoperative radiographs at a follow-up of 2 months. RESULTS: Differences in postoperative mMPTA (p = 0.509) and HKA (p = 0.298) between the two groups were not statistically significant. For the mMPTA target, 24% of knees in the PSI group (85.6° ± 2.1°) and 32% of the CI group (85.0° ± 3.6°) were outliers. For the HKA target, 44% of knees in the PSI group (176.3° ± 2.8°) and 18% of the CI group (177.1° ± 2.3°) were outliers. Considering the two criteria simultaneously, 60% of knees in the PSI group and 45% of knees in the CI group were outside the target zone (p = 0.324), whereas 28% of knees in the PSI group and 41% of knees in the CI group were outside the target zone by more than 1° (p = 0.357). CONCLUSIONS: The results of the present study revealed no statistically significant difference in radiographic coronal alignment of UKA performed using PSI versus CI for tibial resections.

[Meta analysis of three-dimensional printing patient-specific instrumentation versus conventional instrumentation in total knee arthroplasty].

Objective: To evaluate the effects of three-dimensional printing patient-specific instrumentation(PSI) versus conventional instrumentation(CI) in the total knee arthroplasty. Methods: According to "patient-specific" , "patient-matched" , "custom" , "Instrumentation" , "Guide Instrumentation" , "cutting blocks" , "total knee arthroplasty" , "total knee replacement" , "TKA" and "TKR" , the literature on PubMed, EMbase, Cochrane library, CBM and WanFang were searched. According to the inclusion and exclusion criteria, the high quality randomized control trial (RCT) studies about three-dimensional (3D) printing patient-specific instrumentation versus conventional instrumentation in the total knee arthroplasty were collected. The post-operative limb mechanical axis outlier, the position of the components outlier, post-operative knee function, operative time, post-operative blood transfusion and complications were analyzed by RevMan 5.3 software. Results: A total of 13 high quality RCT studies were included. The results of Meta-analysis show that there were no statistical differences in the post-operative limb mechanical axis outlier(Z=0.55, P=0.58, 95% CI: 0.78 to 1.56), femoral coronal component outlier(Z=0.38, P=0.71, 95% CI: 0.69 to 1.72), tibia coronal component outlier(Z=1.95, P=0.05, 95% CI: 1.00 to 3.38), femoral rotation angle outlier(Z=0.36, P=0.72, 95% CI: 0.49 to 1.64), post-operative knee function(Z=1.18, P=0.24, 95% CI: -0.66 to 2.63), post-operative blood transfusions(Z=0.74, P=0.46, 95% CI: -0.10 to 0.05) and complications(Z=0.18, P=0.86, 95%CI: -0.07 to 0.05) between the PSI group and the CI group. But there are statistical differences in the operation time(Z=2.66, P=0.01, 95% CI: -15.97 to -2.41)and tibia sagittal component outlier (Z=3.69, P=0.00, 95% CI: 1.43 to 3.18)between the PSI group and the CI group. Conclusions: In the primary total knee arthroplasty the PSI is not superior over the CI for the knee without severe knee varus or valgus deformity or contracture deformity, without the deformity around the knee and without the knee bone loss and obesity. The use of PSI in the primary total knee arthroplasty are not recommend.

Meta analysis of three-dimensional printing patient-specific instrumentation versus conventional instrumentation in total knee arthroplasty / 中华外科杂志

Objective@#To evaluate the effects of three-dimensional printing patient-specific instrumentation(PSI) versus conventional instrumentation(CI) in the total knee arthroplasty.@*Methods@#According to "patient-specific" , "patient-matched" , "custom" , "Instrumentation" , "Guide Instrumentation" , "cutting blocks" , "total knee arthroplasty" , "total knee replacement" , "TKA" and "TKR" , the literature on PubMed, EMbase, Cochrane library, CBM and WanFang were searched. According to the inclusion and exclusion criteria, the high quality randomized control trial (RCT) studies about three-dimensional (3D) printing patient-specific instrumentation versus conventional instrumentation in the total knee arthroplasty were collected. The post-operative limb mechanical axis outlier, the position of the components outlier, post-operative knee function, operative time, post-operative blood transfusion and complications were analyzed by RevMan 5.3 software.@*Results@#A total of 13 high quality RCT studies were included. The results of Meta-analysis show that there were no statistical differences in the post-operative limb mechanical axis outlier(Z=0.55, P=0.58, 95% CI: 0.78 to 1.56), femoral coronal component outlier(Z=0.38, P=0.71, 95% CI: 0.69 to 1.72), tibia coronal component outlier(Z=1.95, P=0.05, 95% CI: 1.00 to 3.38), femoral rotation angle outlier(Z=0.36, P=0.72, 95% CI: 0.49 to 1.64), post-operative knee function(Z=1.18, P=0.24, 95% CI: -0.66 to 2.63), post-operative blood transfusions(Z=0.74, P=0.46, 95% CI: -0.10 to 0.05) and complications(Z=0.18, P=0.86, 95%CI: -0.07 to 0.05) between the PSI group and the CI group. But there are statistical differences in the operation time(Z=2.66, P=0.01, 95% CI: -15.97 to -2.41)and tibia sagittal component outlier (Z=3.69, P=0.00, 95% CI: 1.43 to 3.18)between the PSI group and the CI group.@*Conclusions@#In the primary total knee arthroplasty the PSI is not superior over the CI for the knee without severe knee varus or valgus deformity or contracture deformity, without the deformity around the knee and without the knee bone loss and obesity. The use of PSI in the primary total knee arthroplasty are not recommend.

No difference in mechanical alignment and femoral component placement between patient-specific instrumentation and conventional instrumentation in TKA.

PURPOSE: There is a rising interest in the use of patient-specific instrumentation (PSI) during total knee arthroplasty (TKA). The goal of this meta-analysis was to compare PSI with conventional instrumentation (CI) in patients undergoing TKA. METHODS: A literature search was performed in PubMed, Embase, Springer, Ovid, China National Knowledge Infrastructure, and the Cochrane Library. A total of 10 randomized controlled studies involving 837 knees comparing outcomes of PSI TKAs with CI TKAs were included in the present analysis. Outcomes of interest included component alignment, surgical time, blood loss, and hospital stay. RESULTS: The results presented no significant differences between the two instrumentations in terms of restoring a neutral mechanical axis and femoral component placement. However, their differences have been noted regarding the alignment of the tibial component in coronal and sagittal planes. Also, 3 min less surgical time was used in PSI patients. CONCLUSIONS: Based on these findings, PSI appeared not to be superior to CI in terms of the post-operative mechanical axis of the limb or femoral component placement. Despite a statistical difference for operative duration, the benefit of a small reduction in surgical time with PSI is clinically irrelevant. LEVEL OF EVIDENCE: Therapeutic study (systematic review and meta-analysis), Level I.