Introduction. Robotic-assisted total knee arthroplasty (TKA) has demonstrated significant benefits, including improved accuracy of component positioning compared to conventional jig-based TKA. However, previous studies have often failed to associate these findings with clinically significant improvements in patient-reported outcome measures (PROMs). Inertial measurement units (IMUs) provide a more nuanced assessment of a patient's functional recovery after TKA. This study aims to compare outcomes of patients undergoing robotic-assisted and conventional TKA in the early postoperative period using conventional PROMS and wearable sensors. Method. 100 patients with symptomatic end-stage knee osteoarthritis undergoing primary TKA were included in this study (44 robotic-assisted TKA and 56 conventional TKA). Functional outcomes were assessed using ankle-worn IMUs and PROMs. IMU- based outcomes included impact load, impact asymmetry, maximum knee flexion angle, and bone stimulus. PROMs, including Oxford Knee Score (OKS), EuroQol-Five Dimension (EQ-5D-5L), EuroQol Visual Analogue Scale (EQ-VAS), and Forgotten Joint Score (FJS-12) were evaluated at preoperative baseline, weeks 2 to 6 postoperatively, and at 3-month postoperative follow-up. Results. By postoperative week 6, when compared to conventional TKA, robotic-assisted TKA was associated with significant improvements in maximum knee flexion angle (118o ± 6.6 vs. 113o ± 5.4; p=0.04), symmetrical loading of limbs (82.3% vs.22.4%; p<0.01), cumulative impact load (146.6% vs 37%; p<0.01), and bone stimulus (25.1% vs 13.6%; p<0.01). Whilst there were no significant differences in PROMs (OKS, EQ-5D-5L, EQ-VAS, and FJS-12) at any time point between the two groups, when comparing OKS subscales, significantly more robotic-assisted TKA patients achieved an ‘excellent’ outcome at 6 weeks compared to conventional (47% vs 41%, p= 0.013). Conclusions. IMU-based metrics detected an earlier return to function among patients that underwent robotic-assisted TKA compared to conventional TKA that PROMs were unable to detect within the first six weeks of surgery

Aims. Robotic-assisted total knee arthroplasty (RA-TKA) has been introduced to provide accurate bone cuts and help achieve the target knee alignment, along with symmetric gap balancing. The purpose of this study was to determine if any early clinical benefits could be realized following TKA using robotic-assisted technology. Methods. In all, 140 consecutive patients undergoing RA-TKA and 127 consecutive patients undergoing conventional TKA with minimum six-week follow-up were reviewed. Differences in visual analogue scores (VAS) for pain at rest and with activity, postoperative opiate usage, and length of stay (LOS) between the RA-TKA and conventional TKA groups were compared. Results. Patients undergoing RA-TKA had lower average VAS pain scores at rest (p = 0.001) and with activity (p = 0.03) at two weeks following the index procedure. At the six-week interval, the RA-TKA group had lower VAS pain scores with rest (p = 0.03) and with activity (p = 0.02), and required 3.2 mg less morphine equivalents per day relative to the conventional group (p < 0.001). At six weeks, a significantly greater number of patients in the RA-TKA group were free of opioid use compared to the conventional TKA group; 70.7% vs 57.0% (p = 0.02). Patients in the RA-TKA group had a shorter LOS; 1.9 days versus 2.3 days (p < 0.001), and also had a greater percentage of patient discharged on postoperative day one; 41.3% vs 20.5% (p < 0.001). Conclusion. Patients undergoing RA-TKA had lower pain levels at both rest and with activity, required less opioid medication, and had a shorter LOS

Aims. Around the world, the emergence of robotic technology has improved surgical precision and accuracy in total knee arthroplasty (TKA). This territory-wide study compares the results of various robotic TKA (R-TKA) systems with those of conventional TKA (C-TKA) and computer-navigated TKA (N-TKA). Methods. This is a retrospective study utilizing territory-wide data from the Clinical Data Analysis and Reporting System (CDARS). All patients who underwent primary TKA in all 47 public hospitals in Hong Kong between January 2021 and December 2023 were analyzed. Primary outcomes were the percentage use of various robotic and navigation platforms. Secondary outcomes were: 1) mean length of stay (LOS); 2) 30-day emergency department (ED) attendance rate; 3) 90-day ED attendance rate; 4) 90-day reoperation rate; 5) 90-day mortality rate; and 6) surgical time. Results. A total of 8,492 knees from 7,746 patients were included in the study. Overall robotic use had risen to 20.4% (2023 Q3 to Q4: 355/1,738) by the end of 2023, with Mako being the most popular at 10.3% (179/1,738). R-TKA had the shortest mean LOS compared with N-TKA and C-TKA (5.5 vs 6.3 and 7.1 days, respectively; p < 0.001). Only Mako (9.7%) demonstrated reduced 90-day ED attendance compared to C-TKA (13.1%; p = 0.009), Cori/Navio (15.0%; p = 0.005), and Rosa (16.4%; p < 0.001). No differences in 90-day reoperation rate and mortality were observed between all groups. Mean surgical times were longer in R-TKA groups by 20.6 minutes (p < 0.001). Conclusion. R-TKA use has increased in recent years, and has been shown to reduce hospital stay despite having a slightly longer surgical time, proving a promising candidate to alleviate the burden on healthcare systems. Individual differences between R-TKA systems contributed to variable clinical outcomes. Cite this article: Bone Jt Open 2024;6(1):12–20

Introduction. Robotic-assisted total knee arthroplasty (TKA) was introduced to improve limb alignment, component positioning, and soft-tissue balance, yet the effect of adoption of this technology has not been established. This study was designed to evaluate whether robotic-assisted TKA leads to improved patient reported outcome measures (PROMs) and patient satisfaction as compared to conventional TKA at 3 and 12 months. Methods. This IRB-approved single-surgeon retrospective cohort analysis of prospectively collected data compared 113 conventional TKA patients with 145 imageless robotic-assisted TKA patients (Navio™ Surgical System, Smith&Nephew®, Memphis TN). Basic demographic information, intraoperative and postoperative data, and PROMs (SF-P, SF-M, WOMAC pain, WOMAC stiffness, WOMAC Physical Function, KSS) were collected and recorded preoperatively, at 3 months, and at 12 months following surgery. Range of motion (ROM), blood loss, surgical duration, and complication rates between groups were also collected. Continuous measures such as mean difference in PROMs and ROM were compared using unpaired t-tests. Categorical measures such as the percentage of patients with complications were compared using chi-square analysis. Results. There were no baseline demographic differences or preoperative PROMs between groups. Following TKA, there were no differences between groups with respect to ROM or any of the PROMs (SF-P, SF-M, WOMAC pain, WOMAC stiffness, WOMAC Physical Function, and KS scores) at 3- or 12-months. Difference between the group included larger EBL(242 vs 209 mL, p<.001) and longer surgical duration (119 vs 107minutes, p<.001) for robotic-assisted surgery. There were no differences between the two groups in total post operative complications however subgroup analysis demonstrated that the robotic assisted cohort had fewer periprosthetic joint infections (1 vs 3, p=.048) and total reoperations (1 vs 7, p=.0114). Conclusions. Imageless robotic-assisted TKA resulted in similar function and satisfaction scores when compared to conventional TKA at 3 and 12 months. While EBL and surgical duration were greater with robotic-assisted TKA, this technique resulted in fewer reoperations and periprosthetic wound infections. For figures, tables, or references, please contact authors directly

Objective. Computer-assisted minimally invasive total knee arthroplasty (CAMI-TKA) has gained increasing interest from orthopaedic surgeons due to its advantages in improving accuracy of component placement combined with benefits in postoperative recovery due to a smaller incision. However, long-term clinical and radiographic outcomes are lacking. The purpose of the present study is to compare the long-term radiographic features and functional outcomes between patients who underwent CAMI-TKA and those who underwent conventional TKA. Methods. One hundred and eight patients who were randomized to undergo CAMI-TKA or conventional TKA during 2004 and 2005 were contacted by phone for a prospective follow-up review. Patients who have passed away or declined to participate in the study were excluded. Patients were asked to return to the hospital for clinical and functional assessments, long-leg and knee roentgenograms. Baseline characteristics were compared to account for potential confounders and multivariate statistical analysis applied to account for any differences in baseline characteristics. Results. As shown in Figure 1, a total of 101 patients (93.52%) were contacted, and 69 patients (63.89%) returned to hospital for assessments and investigations. By the time of this study, two patients from the Conventional TKA group had undergone revision TKA, one due to infection and one due to aseptic loosening. The average follow up time was 9.07 years (8.51–9.61 years). Subsequent comparison was carried out between 37 patients from the conventional TKA group and 30 from the CAMI-TKA group. Both groups had similar pre-operative demographics, clinical and functional assessments except for the Function Score component of the Knee Society Score (Conventional=50 vs. CAMI=55, p=0.049). At follow-up, the Short Form-36 and Knee Society Scores were comparable between the two groups. However, patients from CAMI group reported a significantly higher Oxford Knee Score compared to those from conventional group (p=0.013). No significant intergroup differences were found in mechanical knee alignment and component placement angle in the coronal views. In the sagittal views, the femoral components demonstrated a more extensional configuration in the conventional group, in contrary to a more flexional configuration in the CAMI group (1.0° extension vs. 1.5° flexion, p<0.001). There also existed a significant difference in sagittal tibial component angles, where the conventional group had a steeper posterior slope compared to the CAMI group (5.1° vs. 2.5°, p=0.002). Four knees from CAMI-TKA group and 1 knee from Conventional TKA group were found to have non-progressive radiolucencies between the components and bone cuts, without statistical or clinical significance. No other patients demonstrated any migrating or shifting of the prosthesis that could be construed as possible failure in either group. Conclusions. Computer-assisted minimally invasive total knee arthroplasty provided similar clinical, functional, and radiographic outcomes compared with conventional total knee arthroplasty after an average of 9 years follow-up. This technique can be employed to exploit its short-term advantages without compromising long-term clinical and radiographic outcomes

Recent advancements in optical navigated TKA have shown improved overall limb alignment, implant placement and reduced outliers compared to conventional TKA. This study represents the first RCT comparing EM navigation and conventional TKA. 3D alignment was analysed from CT scans. Clinical scores (Oxford Knee Score (OKS) and American Knee Society Score (AKSS)) were recorded at pre-op, 3 and 12 months post-op. Data presented includes 180 patients (n=90 per group) at 3 months and 140 (n=70 per group) at 12 months. The groups had similar mean mechanical axis alignments (EM 0.31° valgus; conventional 0.15° valgus). Mechanical axis alignment however was improved in the EM group with 92% within +/−3° of neutral compared to 84% of the conventional group (p=0.90). The EM group showed improved coronal and sagittal femoral alignment and improved coronal, sagittal and rotational tibial alignment, which was significant for sagittal femoral alignment (p=0.04). The OKS and AKSS scores were significantly better for the EM group at 3 months post-op (OKS p=0.02, AKSS p=0.04), but there was no difference between groups at 12 months. The mean pre-op range of motion (ROM) for both groups was 105°. This decreased at 3 months to 102° in the EM group and 99° in the conventional group, but there was a significant improvement by 12 months: EM=113° (p=0.012) and conventional=112° (p=0.026). ROM was statistically similar between groups at all assessment phases. Knee alignment was better restored following EM navigated TKA relative to conventional TKA, but the difference was not significant. The EM group showed greater clinical improvements at early follow-up; however this difference was not sustained at 12 months. ROM was seen to decrease at 3 months but then significantly improve by 12 month post-op. Proving cost-effectiveness for navigation systems in TKA remains a challenge

This RCT compared electromagnetic (EM) navigated and conventional total knee arthroplasty (TKA) in terms of clinical and functional outcomes. 200 patients (navigated=102, conventional=98) were recruited. Oxford Knee Scores (OKS) and the American Knee Society Score (AKSS) were recorded pre operation, 3 and 12 months after surgery. Post operative (coronal, sagittal and rotational) alignment was analysed from 3D CT scans taken 3 months after surgery. An objective functional assessment was completed using electrogoniometry on a sub group (navigated=60, conventional=57) at 12 months post surgery. The EM group showed statistically significantly improved OKS (p=0.04) and AKSS (p=0.03) scores at 3 months post operation. However at 12 months post surgery there was no difference between the two groups. At the 1 year follow up it was reported that 9% of the navigated compared to 14% of the conventional group were dissatisfied with their surgical outcome. The mechanical axis alignment of 90% of the navigated group was within 3 degrees of neutral compared to 84% of the conventional group. Although all alignment parameters except for tibial rotation was improved in the navigated group they did not reach significance apart from femoral slope alignment (p=0.01). There was no statistically difference between the surgical groups in terms of the maximum, minimum and excursion knee joint angles during 12 functional activities. Only the knee kinematic function cycles for level walking resulted in statistically significant higher knee joint angles during 55–70% of the gait cycle in the navigated group. Knee alignment was better restored following EM navigated TKA relative to conventional TKA, but the difference was not significant. The EM group showed greater clinical and functional improvements at early follow-up; however this difference was not sustained at 12 months. The EM group reported minimal gait improvements. Proving cost-effectiveness for navigation systems in TKA remains a challenge

INTRODUCTION. Total knee replacement is mostly done with alignment rods in order to achieve a proper Varus / Valgus alignement. Other techniques are computer assisted navigation or MRI based preoperative planning. iASSIST™ is a computer assisted stereotaxic surgical instrument system to assist the surgeon in the positioning of the orthopaedic implant system components intra-operatively. It is imageless and the communication between the PC and the “Pod's” does not require any direct camera view, it is a bluethooth comunication system. This study presents preliminary results utilizing iASSIST™. The aim of this study was to test and compare radiographic alignment, functional outcomes, and perioperative morbidity of the iASSIST™ Knee system versus conventional total knee arthroplasty. METHODS. In a prospective randomized trial we investigated 60 patients with osteoarthritis of the knee joint. Each surgical procedure was conducted by highly experienced surgeons. In both groups the implant Legacy LPS-Flex Fixed Bearing Knee was used (Zimmer®, Warsaw, Indiana). The groups were equally divided and randomized by hazard. For clinical evaluation, the Short Form-36 and Knee Society Score were obtained. For the radiological assessment mediCAD® Classic, a digital measurement system, was used. The aim of the study was the comparison of results after 3 months. Results. 2 patients refused any further participation, and 5 cases required a switch to a conventional alignement technique intraoperatively due to technical problems. Average BMI and average age did not differ in both groups. Surgical time in the iASSIST™ group amounted to 100 minutes, in the conventional group to 76 min. Postoperative functional outcomes were statistically insignificant, showing slight improvements of the Combined Knee Society Score, Knee Society Knee Score, and Knee Society Function Score favouring the iASSIST method, and slight improvements of knee flexion. Short Form-36 physical scales slightly favoured the conventional method but not significantly. The mean deviation from neutral mechanical axis was 1.68°±1.9° within the iASSIST group, and 2.73°±2.1° within the conventional TKA group. Conclusion. IASSIST™ is a valuable computer navigation system. The 5 technical troubles were due to the learning curve. The clinical results after 3 months did not differ significantly, the radiological assessment showed a tendency of improved alignement in the iASSIST™ group

Few previous studies showed that the conventional total knee replacement (TKR) has affection to the same side of talar tilt (TT). We expected to prevent this problem by the computer-assisted (CAS) TKR. The purpose of this study was to compare between pre and post-operative talar tilt and ankle clinical assessment on the CAS TKR and the Conventional TKR in 28 patients (56 knees) whom underwent bilateral TKR. 28 patients, 56 knees, whom underwent both CAS total knee replacement (TKR) and conventional total knee replacement (TKR), in both knees, with the combination of Gap Balance and Measurement Resection techniques performed by one surgeon (P. Sriphirom) at Rajavithi Hospital, Bangkok. The post-operative has a 12 months follow-up for ankle radiographic finding by tibiotalar angle (TTA), tibial articular surface angle (TAS), and talar tilt (TT) = (TAS-TTA) and for ankle clinical assessment by foot functional index (FFI) from pre-operation and post-operation from both groups. The study also compares the CAS TKR with the Conventional TKR for pre-operation and post-operation. 56 knees, 28 patients, mean age = 67.79 years whom underwent bilateral TKR by the Conventional group and the CAS group had pre-operative TT (TT = TAS − TTA). The Conventional group = 1.5 (−5, 8), the CAS group = 0.5 (−5, 8), P value = 0.65. On post-operative TT the Conventional group = 0.0 (−5, 3), the CAS group = 1.0 (−3, 8), the P value = 0.4. The comparison of pre-operative TT and post-operative TT in the Conventional group, the P value = 0.01. On pre-operative TT and post-operative TT in the CAS group, the P value = 0.65. TT was significantly different in the Conventional group but was not significantly different in the CAS group. The ankle clinical assessment by foot functional index (FFI), which are (1) Pain, (2) Difficulty living, and (3) Daily life activity limitation. The pre-operative FFI in the Conventional group = 1.85 (0.81, 6.88) and pre-operative FFI in the CAS group = 1.91 (0.24, 66.5), the P value = 0.57. The post-operative FFI in the Conventional group = 1.68 (0.24, 7.0) and post-operative FFI in the CAS group = 1.65 (0.24, 6.76), the P value = 0.04, which showed a significantly different between the post-operative FFI from both groups. In the Conventional group the post-operative FFI was not significantly different from pre-operative FFI, the P value = 0.2 but for the CAS group the post-operative FFI was not significantly different from pre-operative FFI, the P value = 0.04. This study showed that the conventional TKR effected to post-operative talar, tilt but CAS TKR has less effect and was not significantly different to ankle joint. Finally, the study needs to be conducted on more patients and to be observed on a longer term follow-up

Electromagnetic navigation versus conventional Total Knee Arthroplasty: Clinical improvements Optical and electromagnetic (EM) tracking systems are widely used commercially. However in orthopaedic applications optical systems dominate the market. Optical systems suffer from deficiencies due to line of sight. EM trackers are smaller but are affected by metal. The accuracy of the two tracker systems has been seen to be comparable1. Recent advancements in optical navigated TKA have shown improved overall limb alignment, implant placement and reduce outliers when compared to conventional TKA2-4. This study is the first RCT to compare EM and conventional TKA. Two groups of 100 patients underwent TKA using either the EM navigation system or the conventional method. Frontal, sagittal and rotational alignment was analysed from a CT scan. Clinical scores including Oxford Knee Score (OKS) and Knee/Function American Knee Society Score (AKSS) were recorded pre-op, and at 3 and 12 months post-op. 3 month data presented includes 180 patients (n = 90). The 12 months data presented includes 140 (n = 70). The two groups had similar mean mechanical axis alignments (EM 0.31o valgus, conventional 0.15o valgus). The mechanical axis alignment was improved in the EM group with 92% within +/-3o of neutral compared to 84% of the conventional group (p = 0.90). The alignment of the EM group was improved in terms of frontal femoral, frontal tibial, sagittal femoral, sagittal tibial and tibial rotation alignment. However, only the sagittal femoral alignment was significantly improved in the EM group (p = 0.04). Clinically, both TKA groups showed significant improvements in OKS and AKSS scores between both pre-op to 3 month post-op and 3 months to 12 months post-op (p<0.001). The OKS and the AKSS knee score for the EM group was significantly better at 3 months post-op (OXS p = 0.02, AKSS knee p = 0.04). However there was no difference between the groups at 12 months. The mean pre-op range of motion (ROM) for both groups was 105o. This decreased to 102o in the EM group and 99o in the conventional group at 3 months. There was a significant improvement at 12 months post-op, EM = 113o (p = 0.012) and conventional = 112o (p = 0.026). There was no significant difference in ROM between the two groups at 3 or 12 months post-op. Therefore the alignment outcome of the EM TKA group was improved compared to the conventional group. The EM group also showed clinical improvements at 3 months post-op however these were not seen again at 12 months post-op. ROM was seen to decrease at 3 months post-op but then significantly improve by 12 month post-op

Systemic embolic phenomena are well recognised during total knee replacement (TKR) and are widely believed to be the cause of intra-operative hypotension and reduced cardiac output, which may lead to circulatory collapse and sudden death. We undertook a prospective, double-blind, randomised study comparing the cardiac embolic load during computer-assisted and conventional (intramedullary-aligned) TKR, as measured by transoesophageal echocardiography. 26 consecutive procedures were performed by a single surgeon at a single site. Embolic load was scored using the modified Mayo grading system for echogenic emboli. Patients undergoing conventional TKR (n=12) had a mean embolic score of 6.15 (SD 0.83) on release of the tourniquet. Those undergoing computer-assisted TKR (n=14) had a mean embolic score of 4.89 (SD 1.10). Comparison of the groups using a two-tailed t-test confirmed a highly significant reduction (p=0.004) in embolic load when performing computer-assisted TKR. The groups were otherwise well matched and there were no complications. In conclusion, this study demonstrates that computer-assisted TKR results in the release of significantly fewer systemic emboli than conventional TKR using intra-medullary alignment. There is evidence that this should reduce perioperative morbidity and neurological dysfunction. This would appear to add to the ever-growing list of arguments in favour of computer-assisted total knee replacement

Background: Computer-assisted navigation systems are supposed to improve the precision of implant positioning and therefore the longevity of the knee arthroplasty. Several studies have demonstrated a better mechanical axis or axial component alignment in navigated compared to conventional TKA at least less outliers from a range of 3° of varus or valgus. It is still unclear wether navigation can improve rotational alignment. Materials and Methods: After informed consent 80 patients were randomized to navigated or conventional TKA. In all patients, a cemented, unconstrained, cruciate-retaining TKA with a rotating platform was implanted. A full-length standing and a lateral radiograph and CT Scans of the hip, knee and ankle joint were done 5 to 7 days postoperatively before discharge. Results: The navigated group showed a median deviation from the mechanical axis of 1,5° with a range between 5,9° valgus and 4,6 varus malalignment. The conventional implanted arthroplasties showed a median deviation from the mechanical axis of 1,6° with a range between 5,9° valgus and 7,2° varus malalignment. 5 navigated and 7 conventional implanted arthroplasties were outside a tolerance level of 3°. The femoral component showed a median deviation from the transepicondylar axis of 1,7° (range: 3,1° external rotation to 4,4° internal rotation) in the navigated group and of 1,0° (range: 3,4° external rotation to 4,3° internal rotation) in the conventional implantations. The tibial component showed a much greater range of rotational deviation from the medial third of the tuberosity in median 5,3° (range: 14,9° external rotation to 26° internal rotation) in the navigated group and 4,8° (range: 6,5° external rotation to 23,8° internal rotation) in the conventional implantations. Conclusion: We could not find a difference between Computer-assisted navigation and conventional implantation for rotational alignment of the femoral or tibial component. While the deviation from the transepicondylar axis was quite low and nearly all implantations were within a range of 3° of internal and external rotation there was a considerable range of deviation for the tibial rotational alignment

We report our five-year functional results comparing navigated and conventional total knee replacement. To our knowlege this represents the first Level 1 study comparing function in navigated and conventional total knee replacement at five years. An origianl cohort of 71 patients undergoing Duracon (Stryker Orthopaedics, St. Leonards, Australia) total knee replacement without patellar resurfacing were prospectively randomised to undergo operation using computer navigation (Stryker Image Free Computer Navigation System (version 1.0; Stryker Orthopaedics))(n=35) or a jig-based method (n=36). The two groups were matched for age, gender, height, weight, BMI, ASA grade abd pre-operative deformity. All operations were performed by a single surgeon. Reviews were undertaken by senior physiotherpist blinded to participant status using validated outcome scoring tools (Knee Society Score, WOMAC Score and Short Form SF-36 Score). All patients underwent CT scanning of the implanted prosthesis as per Perth CT Knee Protocol to assess component alignment. After 5 years 24 patients in the navigated group and 22 patients in the conventional group were available for review. At 5 years no statistically significant difference was seen in any of the aforementioned outcome scores when comparing navigated and conventional groups. No statistically significant differencewas seen between 2- and 5-year results for either group. Due to the relatively low numbers in each group these data were compared with retrospective cohorts of navigated (n=100) and conventional (n=70) Duracon total knee replacements performed outwith this study over the same 5-year period. WITHIN the retrospective cohorts no statistically significant differences were found when comparing any of the aforementioned outcome scores. In addition, when comparing parallel scores between prospective and retrospective groups again no statistically significant differences were identified. At 5-years post-operatively the functional outcome between computer navigated and conventional total knee replacement appears to be no different despite the better alignment achieved using navigation

We previously compared component alignment in total knee replacement using a computer-navigated technique with a conventional jig based method. Improved alignment was seen in the computer-navigated group (Beaver et al. JBJS 2004 (86B); 3: 372–7.). We also reported two-year results showing no difference in clinical outcome between the two groups (Beaver et al. JBJS 2007 (89B); 4: 477–80). We now report our five-year functional results comparing navigated and conventional total knee replacement. To our knowlege this represents the first Level 1 study comparing function in navigated and conventional total knee replacement at five years. An original cohort of 71 patients undergoing Duracon (Stryker Orthopaedics, St. Leonards, Australia) total knee replacement without patellar resurfacing were prospectively randomised to undergo operation using computer navigation (Stryker Image Free Computer Navigation System (version 1.0; Stryker Orthopaedics))(n=35) or a jig-based method (n=36). The two groups were matched for age, gender, height, weight, BMI, ASA grade and pre-operative deformity. All operations were performed by a single surgeon. All patients underwent review in our Joint Replacement Assessment Clinic at 3, 6 and 12 months and at 2 and 5 years. Reviews were undertaken by senior physiotherapist blinded to participant status using validated outcome scoring tools (Knee Society Score, WOMAC Score and Short Form SF-36 Score). All patients underwent CT scanning of the implanted prosthesis as per Perth CT Knee Protocol to assess component alignment. After 5 years 24 patients in the navigated group and 22 patients in the conventional group were available for review. At 5 years no statistically significant difference was seen in any of the aforementioned outcome scores when comparing navigated and conventional groups. No statistically significant difference was seen between 2- and 5-year results for either group. Due to the relatively low numbers in each group these data were compared with retrospective cohorts of navigated (n=100) and conventional (n=70) Duracon total knee replacements performed outwith this study over the same 5-year period. WITHIN the retrospective cohorts no statistically significant differences were found when comparing any of the aforementioned outcome scores. In addition, when comparing parallel scores between prospective and retrospective groups again no statistically significant differences were identified. At 5-years post-operatively the functional outcome between computer navigated and conventional total knee replacement appears to be no different despite the better alignment achieved using navigation

Introduction: We previously compared component alignment in total knee replacement using a computer-navigated technique with a conventional jig based method. Improved alignment was seen in the computer-navigated group (Beaver et al. JBJS 2004 (86B); 3: 372–7.). We also reported two-year results showing no difference in clinical outcome between the two groups (Beaver et al. JBJS 2007 (89B); 4: 477–80). We now report our five-year functional results comparing navigated and conventional total knee replacement. To our knowlege this represents the first Level 1 study comparing function in navigated and conventional total knee replacement at five years. Methods: An original cohort of 71 patients undergoing Duracon (Stryker Orthopaedics, St. Leonards, Australia) total knee replacement without patellar resurfacing were prospectively randomised to undergo operation using computer navigation (Stryker Image Free Computer Navigation System (version 1.0; Stryker Orthopaedics))(n=35) or a jig-based method (n=36). The two groups were matched for age, gender, height, weight, BMI, ASA grade and pre-operative deformity. All operations were performed by a single surgeon. All patients underwent review in our Joint Replacement Assessment Clinic at 3, 6 and 12 months and at 2 and 5 years. Reviews were undertaken by senior physiotherpist blinded to participant status using validated outcome scoring tools (Knee Society Score, WOMAC Score and Short Form SF-36 Score). All patients underwent CT scanning of the implanted prosthesis as per Perth CT Knee Protocol to assess component alignment. Results: After 5 years 24 patients in the navigated group and 22 patients in the conventional group were available for review. At 5 years no statistically significant difference was seen in any of the aforementioned outcome scores when comparing navigated and conventional groups. No statistically significant difference was seen between 2- and 5-year results for either group. Due to the relatively low numbers in each group these data were compared with retrospective cohorts of navigated (n=100) and conventional (n=70) Duracon total knee replacements performed outwith this study over the same 5-year period. WITHIN the retrospective cohorts no statistically significant differences were found when comparing any of the aforementioned outcome scores. In addition, when comparing parallel scores between prospective and retrospective groups again no statistically significant differences were identified. Conclusion: At 5-years post-operatively the functional outcome between computer navigated and conventional total knee replacement appears to be no different despite the better alignment achieved using navigation

Among many factors that influence the outcomes of Total Knee Arthroplasties (TKAs), the mechanical alignment has played major roles for the success of TKA, the survival rates of the implants, and patient functionality. Most, but not all, studies have shown that alignment of the mechanical axis in the coronal plane within a range of 3° varus/valgus is associated with improved long-term function and increased survival rates. Robot-assisted TKA has been developed to improve improves the accuracy and precision of component implantation and mechanical axis (MA) alignment. We hypothesised that robot-assisted TKA would lead to a more accurate leg alignment and component implantation, and thus, improve radiological and clinical outcomes. Between January 2003 and December 2004, a total of 98 primary TKA procedures were compared: 49 using a robotic-assisted procedure and 49 using conventional manual techniques. The cohorts were followed for 121.2 and 119.5 months on average, respectively. Radiographic assessments of the patients were performed preoperatively and at final follow-up and made according to the Knee Society Roentgenographic Evaluation System (KSRES) which included measurements of the coronal mechanical axis and sagittal and coronal inclinations of femoral and tibial components. The radiographic measurements were made using a PACS (Picture Archiving and Communication System). Clinical assessments were performed preoperatively, and at a final follow-up date that was a minimum of postoperative nine years. The clinical results included ranges of motion (ROM), Hospital for Special Surgery (HSS) scores, Western Ontario and McMaster University (WOMAC) scores (for pain and function). The radiographic results showed no statistical differences when comparing the means of the two groups. When considering outliers (defined as error ≥ ±3°) for the mechanical axis, femoral coronal and sagittal inclinations, and tibial coronal and sagittal inclinations, the ROBODOC group had zero outliers for all measurements except for one in tibial sagittal inclination. On the other hand, the conventional group had 12 outliers for mechanical axis, 2 for femoral coronal inclination, 3 for femoral sagittal inclination, 3 for tibial coronal inclination, and 4 for tibial sagittal inclination. However, there were no statistically significant differences between groups for ROM, HSS, or WOMAC scores at the final follow-up. The results of this study support previous work and demonstrate that the ROBODOC-assisted implantation of TKA results in better radiographic outcomes and better ligament balance with equivalent safety when compared to conventional TKA at a minimum follow-up of nine years

A functional total knee replacement has to be well aligned, which implies that it should lie along the mechanical axis and in the correct axial and rotational planes. Incorrect alignment will lead to abnormal wear, early mechanical loosening, and patellofemoral problems. There has been increased interest of late in total knee arthroplasty with robot assistance. This study was conducted to determine if robot-assisted total knee arthroplasty is superior to the conventional surgical method with regard to the precision of implant positioning. Twenty knee replacements of ten robot-assisted and another ten conventional operations were performed on ten cadavers. Two experienced surgeons performed the surgery. Both procedures were undertaken by one surgeon on each cadaver. The choice of which was to be done first was randomized. After the implantation of the prosthesis, the mechanical-axis deviation, femoral coronal angle, tibial coronal angle, femoral sagittal angle, tibial sagittal angle, and femoral rotational alignment were measured via three-dimensional CT scanning. These variants were then compared with the preoperative planned values. In the robot-assisted surgery, the mechanical-axis deviation ranged from −1.94 to 2.13° (mean: −0.21°), the femoral coronal angle ranged from 88.08 to 90.99° (mean: 89.81°), the tibial coronal angle ranged from 89.01 to 92.36° (mean: 90.42°), the tibial sagittal angle ranged from 81.72 to 86.24° (mean: 83.20°), and the femoral rotational alignment ranged from 0.02 to 1.15° (mean: 0.52°) in relation to the transepicondylar axis. In the conventional surgery, the mechanical-axis deviation ranged from −3.19 to 3.84°(mean: −0.48°), the femoral coronal angle ranged from 88.36 to 92.29° (mean: 90.50°), the tibial coronal angle ranged from 88.15 to 91.51° (mean: 89.83°), the tibial sagittal angle ranged from 80.06 to 87.34° (mean: 84.50°), and the femoral rotational alignment ranged from 0.32 to 4.13° (mean: 2.76°) in relation to the transepicondylar axis. In the conventional surgery, there were two cases of outlier outside the range of 3° varus or valgus of the mechanical-axis deviation. The robot-assisted surgery showed significantly superior femoral-rotational-alignment results compared with the conventional surgery (p=0.006). There was no statistically significant difference between robot-assisted and conventional total knee arthroplasty in the other variants. All the variants were measured with high intraobserver and interobserver reliability. In conclusion, Robot-assisted total knee arthroplasty showed excellent precision in the sagittal and coronal planes of the three-dimensional CT. Especially, better accuracy in femoral rotational alignment was shown in the robot-assisted surgery than in the conventional surgery despite the fact that the surgeons who performed the operation were more experienced and familiar with the conventional surgery than with robot-assisted surgery. It can thus be concluded that robot-assisted total knee arthroplasty is superior to the conventional total knee arthroplasty

D-dimer is one of the useful laboratory tests to evaluate the incidence of venous thromboembolism (VTE) after the total knee arthroplasty (TKA). The most recent guideline for the prophylaxis of VTE points out the surgical procedure itself is a major risk factor for developing VTE. Only a few literatures discuss the relationship of surgical procedures and the risk of venous thromboembolism. We therefore prospectively compare the difference of the perioperative plasma D-dimer levels between the patients undergoing navigation and convention TKA. Two hundred consecutive total knee arthroplasties were performed between September 2011 and March 2013. The patients were randomised according to their registration to the orthopaedic clinic. Ninety-six patients (100 knees) underwent a navigation-assisted TKA and ninety-four patients (100 knees) had a conventional TKA. No intramedullary violation was done in the navigation-assisted TKA, while the intramedullary femoral guiding was adapted in the conventional group. Pre-operative and post-operation day 1 plasma D-dimer levels were recorded and evaluated using Mann-Whitney U test. There was no difference in the demographic data and pre-operative D-dimer between the two groups (p=0.443). Significantly lower D-dimer levels on the post-operative day 1 were noted in the navigation group, when compared with the conventional group. (6.0 ± 4.4 mg/L vs 11.3 ± 9.6 mg/L, p = 0.000). We demonstrated that lower D-dimer level is developed after the navigation-assisted TKA than the conventional one. Less incidence of VTE is expected and the finding may help to explain the fact that less systemic emboli in the navigation assisted TKA

Introduction

Robot-assisted total knee arthroplasty (RA-TKA) is theoretically more accurate for component positioning than TKA performed with mechanical instruments (M-TKA). Furthermore, the ability to quantify soft tissue laxity and adjust the plan prior to bone resection should reduce variability in polyethylene thickness. This study was performed to compare accuracy to plan for component positioning and polyethylene thickness in RA-TKA versus M-TKA.

Abstract