Manual Total Knee Arthroplasty Research Articles

Comparing Rates of Minimal Clinically Important Difference Between Manual and Robotic-Assisted Total Knee Arthroplasty

BackgroundDifferences in patient-reported outcome measures (PROMs) between manual total knee arthroplasty (mTKA) and robotic-assisted TKA (rTKA) have not been adequately assessed. We compared the minimal clinically important difference (MCID) for improvement (MCID-I) and worsening (MCID-W) between mTKA and rTKA patients. MethodsPatients who underwent primary TKA (874 mTKA and 439 rTKA) with complete preoperative and 1-year postoperative PROMs were retrospectively identified using a multihospital joint arthroplasty registry. Patient-Reported Outcomes Measurement Information System Physical Function Short Form 10a (PROMIS PF-10a), PROMIS Global – Physical, or Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form were collected. The MCID-I, MCID-W, and “no significant change” rates were calculated using distribution-based methods. Propensity score matching was performed to control for confounding. ResultsSimilar 90-day pulmonary embolism (P = 0.26), deep venous thrombosis (P = 0.67), and emergency department visit (P = 0.35) rates were found. The 90-day readmission rate for mTKA was 1.7 and 3.4% for rTKA (P = 0.08), and the overall revision rates were 2.2% for mTKA and 0.7% for rTKA (P = 0.07). Revision-free survival was 99% at one and 2 years for both groups (P = 0.65 and P = 0.43, respectively). There were no differences in the proportion of patients achieving MCID-I or MCID-W for PROMIS PF-10a, PROMIS Global – Physical, or Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form. The MCID-I for PROMIS PF-10a was achieved in 65.5 and 62.2% of patients who had mTKA and rTKA, respectively (P = 0.32). ConclusionsOur study demonstrated similar complication rates and MCID-I and MCID-W attainment rates between mTKA and rTKA patients. Future studies should assess MCID attainment rates in the long term and in larger cohorts comparing mTKA and rTKA.

Mid-Flexion Instability in Total Knee Arthroplasty: Insights from Robotic-Assisted Surgery

Despite technological advancements with robotic-assisted surgery, instability remains a challenge in total knee arthroplasty (TKA). Mid-flexion instability (MFI) has been reported to cause patient dissatisfaction. With no universal diagnostic criteria, the MFI concept is still ambiguous, and no specific treatment algorithm is defined. This study aims to analyze the MFI concept and risk factors and investigate how robotic surgery, compared to manual TKA, could impact the MFI concept. A comprehensive investigation of the current literature regarding MIF, focusing especially on its relationship with robotic surgery TKA, was conducted using the PubMed and Scopus databases. The MIF concept remains poorly understood, so it is crucial to prevent it by recognizing risk factors, which are technique-related, implant-related, and patient-related. Since robotics offers optimal balancing in TKA and reduces causes affecting MFI, it could indirectly impact and prevent this complication. This review suggests that robotics utilization improving TKA balancing has the potential to impact and reduce MFI. However, further research in this area is essential to provide insight regarding the role of robotics in mitigating the MFI risk.

Postoperative Complications and Readmission Rates in Robotic-Assisted Versus Manual Total Knee Arthroplasty: Large, Propensity Score-Matched Patient Cohorts.

There is a paucity of research comparing postoperative complication rates between manual total knee arthroplasty (M-TKA) and robotic-assisted total knee arthroplasty (RA-TKA). This study aims to compare 90-day postoperative complication, readmission, and emergency department rates between RA-TKA and M-TKA. A retrospective review of a multihospital database identified patients who underwent TKA between January 2016 and May 2023. Surgeons who used the robotic-assisted surgery technique in <10% or >90% of their cases annually were excluded. This resulted in 15,999 cases (8,853 RA-TKAs; 7,146 M-TKAs) from 282 surgeons. RA-TKA and M-TKA cohorts were one-to-one matched based on patient sex, age, body mass index, hospital setting, surgeon experience, primary payer, and anesthesia type. Each cohort consisted of 7,146 patients (N = 14,292). 90-day revisits, specifically readmissions, readmissions with >23 hours of observation, and ED visit rates were compared between cohorts. Complications were classified according to the Clinical Classification Software schema and compared between cohorts. Mann-Whitney U, chi-squared, and Fisher exact tests, along with Bonferroni correction, were used to statistically compare cohorts. All-cause 90-day readmission rates were 2.4% for RA-TKA and 2.6% for M-TKA (P = 0.36). RA-TKA had fewer revisits (RA-TKA: 7.8%; M-TKA: 8.8%, P = 0.027) and rates of readmission with >23 hours of observation (RA-TKA: 1.4%; M-TKA: 2.0%, P = 0.003). RA-TKA had fewer hospital revisits due to joint stiffness (RA-TKA: 17 revisits; M-TKA: 42 revisits, P = 0.002) and chronic pain (RA-TKA: 1 revisit; M-TKA: 8 revisits, P = 0.039). Fewer readmissions were observed for acute injuries (lower extremity muscle/tendon strains) in the RA-TKA cohort (RA-TKA: 1; M-TKA: 9, P = 0.021). RA-TKA had fewer ED visits due to hematomas (RA-TKA: 0 visits; M-TKA: 7 visits, P = 0.016). In this retrospective matched cohort analysis, RA-TKA was associated with markedly fewer revisits and readmissions with >23 hours of observation compared with M-TKA. No differences in all-cause 90-day readmission were observed between cohorts. Level III. Retrospective review.

Robotic Assisted TKA achieves adjusted mechanical alignment targets more consistently compared to manual TKA without improving outcomes.

Robotic total knee arthroplasty (rTKA), with its purported advantages of more accurate alignment, greater functional outcomes and patient satisfaction, is gaining popularity in patients undergoing TKA. The purpose of our study was to compare these parameters along with gait pattern and kneeling ability in a cohort of patients who underwent simultaneous TKA with manual instrumentation (mTKA) and rTKA in contralateral knees at a 1-year follow-up. This was a retrospective review of 135 consecutive patients who underwent simultaneous bilateral TKA using robotic assistance on one side and manual instrumentation on the contralateral side between January 2022 and June 2022. The target alignment in both cohorts was adjusted mechanical. Patients were followed up at 3, 6 and 12 months to assess and compare alignment, range of motion (ROM) and patient-reported outcome measures (PROM) data. Gait parameters and kneeling ability were assessed at 1-year follow-up. While adjusted mechanical alignment was achieved in all rTKA patients, we recorded five outliers (≥3° with relation to 180° HKA axis) in the mTKA cohort (three varus and two valgus). There were no significant differences between both cohorts with regards to ROM, PROM scores, gait analysis parameters and kneeling ability at 1-year follow-up. rTKA helps in achieving the adjusted mechanical alignment more consistently than mTKA. This, however, does not contribute to better functional outcomes and patient satisfaction at 1-year follow-up. Level III.

Early Clinical and Economic Outcomes for the VELYS Robotic-Assisted Solution Compared with Manual Instrumentation for Total Knee Arthroplasty.

Robotic-assisted total knee arthroplasty (TKA) has been developed to improve functional outcomes after TKA by increasing surgical precision of bone cuts and soft tissue balancing, thereby reducing outliers. The DePuy Synthes VELYS robotic-assisted solution (VRAS) is one of the latest entrants in the robotic TKA market. Currently, there is limited evidence investigating early patient and economic outcomes associated with the use of VRAS. The Premier Healthcare Database was analyzed to identify patients undergoing manual TKA with any implant system compared with a cohort of robotic-assisted TKAs using VRAS between September 1, 2021 and February 28, 2023. The primary outcome was all-cause and knee-related all-setting revisits within 90-day post-TKA. Secondary outcomes included number of inpatient revisits (readmission), operating room time, discharge status, and hospital costs. Baseline covariate differences between the two cohorts were balanced using fine stratification methodology and analyzed using generalized linear models. The cohorts included 866 VRAS and 128,643 manual TKAs that had 90-day follow-up data. The rates of both all-cause and knee-related all-setting follow-up visits (revisits) were significantly lower in the VRAS TKA cohort compared with the manual TKA cohort (13.86 vs. 17.19%; mean difference [MD]: -3.34 [95% confidence interval: -5.65 to -1.03] and 2.66 vs. 4.81%; MD: -2.15 [-3.23 to -1.08], respectively, p-value < 0.01) at 90-day follow-up. The incidence of knee-related inpatient readmission was also significantly lower (53%) for VRAS compared with manual TKA. There was no significant difference between total cost of care at 90-day follow-up between VRAS and manual TKA cases. On average, the operating room time was higher for VRAS compared with manual TKA (138 vs. 134 minutes). In addition, the discharge status and revision rates were similar between the cohorts. The use of VRAS for TKA is associated with lower follow-up visits and knee-related readmission rates in the first 90-day postoperatively. The total hospital cost was similar for both VRAS and manual TKA cohort while not accounting for the purchase of the robot.

Comparison of the efficacy and safety of MAKO robot-assisted total knee arthroplasty versus conventional manual total knee arthroplasty in uncomplicated unilateral total knee arthroplasty a single-centre retrospective analysis

PurposeTo compare the efficacy and safety of MAKO robot-assisted total knee arthroplasty (MA-TKA) with conventional manual total knee arthroplasty (CM-TKA) in patients with end-stage knee osteoarthritis (KOA) during the early postoperative period.MethodA retrospective analysis was conducted on 22 patients with KOA who underwent MA-TKA and 26 patients who underwent CM-TKA from April 2023 to July 2023. Hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), American Knee Society Score (AKSS), Forgotten Joint Score-12 (FJS-12), visual analogue scale (VAS), and postoperative complications were recorded and compared between the two groups.ResultBoth groups successfully completed the surgeries. In terms of radiographic parameters, postoperative one month LDFA and HKA in the MA-TKA group were significantly lower than those in the CM-TKA group (P < 0.05). At the one month follow-up, 19 patients (86.4%) in the MA-TKA group had an HKA less than 3°, compared to 20 patients (76.9%) in the CM-TKA group. Clinically, VAS scores at 24 h, 48 h, and 72 h postoperatively were lower in the MA-TKA group both at rest and during activity. At one month and three months postoperatively, AKSS Function Scores and FJS-12 scores in the MA-TKA group were significantly higher than those in the CM-TKA group (P < 0.05). Regarding postoperative complications, no complications occurred in the MA-TKA group, while one patient in the CM-TKA group experienced postoperative knee stiffness, which resolved after physical therapy, with no statistically significant difference (P > 0.05).ConclusionCompared with conventional manual total knee arthroplasty, MAKO robot-assisted TKA demonstrates better short-term clinical efficacy, achieves better alignment planning, and maintains good safety.

Noise-Induced Hearing Loss: Should Surgeons Be Wearing Ear Protection During Primary Total Joint Arthroplasty?

The risk of noise-induced hearing loss (NIHL) to orthopedic surgeons due to occupational exposures is unknown. A level of 85 decibels (dB) over an 8-hour time-weighted average (TWA) is considered hazardous. We sought to identify whether manual and/or robotic arthroplasty procedures increase surgeons' risk of developing NIHL. At our institution, we prospectively collected intraoperative recordings with a microphone attached to the surgeon during manual total knee arthroplasty (TKA), manual total hip arthroplasty (THA), and robotic-assisted total knee arthroplasty (RTKA). Recordings taken in the operating room without operating room staff present served as baseline controls. The 172 recordings consisted of 46 baseline, 42 THA, 40 TKA, and 44 RTKA recordings. Decibel levels were reported as "maximum dB level" (the highest sound pressure level using an A-weighted dB scale), "LAeq" (the equivalent continuous sound level), "LCpeak" (the peak sound pressure level using a C-weighted dB scale), and "TWA" (the average dB level projected over an 8-hour period). The percentage of allowable daily noise dose was reported as "dose" and the measured dose projected over 8 hours as "projected dose." The recordings of surgeries had average maximum dB levels ranging from 106.0 to 108.0 dB, all significantly greater than controls. Robotic-assisted total knee arthroplasties had the highest average dose (18.7%) and average projected dose (252.0%). Our review of recordings at a single institution found that noise levels of RTKAs surpassed projected doses of 100%. Orthopedic surgeons performing more than 2 RTKAs per day may be at increased risk of NIHL. Further research is needed to assess the effectiveness of measures such as ear protection to minimize surgeons' exposure.

Analysis of the Initial Learning Curve for Robotic-Assisted Total Knee Arthroplasty Using the ROSA® Knee System.

Background/Objectives: Total knee arthroplasty (TKA) is a frequent procedure in orthopedic surgery. Advances in TKA include the development of robotic-assisted systems. Training in raTKA entails a learning curve to achieve proficiency comparable to conventional manual TKA (maTKA). Methods: We conducted a prospective study of the learning curve in raTKA using the Robotic Surgical Assistant (ROSA) Knee System. The study included 180 patients (90 raTKAs; 90 maTKAs) and three surgeons (one with >15 years of experience in maTKA). The cumulative sum control chart method (CUSUM) was used to define the transition from the learning phase to the mastered phase in raTKA. Results: The learning curves were 43 cases (experienced surgeons) and 61 cases (all surgeons). Mean operative times for both phases in raTKA were longer than in maTKA (p < 0.001). In raTKA, operative times in the learning phase were longer compared to those in the mastered phase (p < 0.001). Operative times in the learning and mastered phases for all surgeons in raTKA were significantly longer compared to those in maTKA (p < 0.001); however, operative times of the experienced surgeon in the mastered phase of raTKA and in maTKA showed no differences. Conclusions: The learning curve in raTKA is dependent upon the surgeon's previous experience in maTKA.

Robotic-assisted total knee arthroplasty is associated with the use of thinner polyethylene liners compared to navigation-guided and manual techniques.

The purpose of this study was to examine the effects of intraoperative technology use on the rate of using polyethylene liners 15 mm or greater during primary total knee arthroplasty (TKA). There were 103,295 implants from 16,386 primary unilateral TKAs performed on 14,253 patients at a single institution between 1 January2018, and 30 June2022, included in the current study. Robotic assistance and navigation guidance were used in 1274 (8%) and 8345 (51%) procedures, respectively. The remaining 6767 TKAs (41%) were performed manually. Polyethylene liners were manually identified and further subcategorised by implant thickness. Patients who underwent robotic-assisted TKA were younger (p < 0.001) and more likely to be male (p < 0.001) compared to patients who underwent navigation-guided or manual TKAs. Average polyethylene liner thickness was similar between groups (10.5 ± 1.5 mm for robotic-assisted TKAs, 10.9 ± 1.8 mm for navigation-guided TKAsand 10.8 ± 1.8 mm for manual TKAs). The proportions of polyethylene liners 15 mm or greater used were 4.9%, 3.8%and 1.9% for navigation-guided, manual and robotic-assisted procedures, respectively (p < 0.001). Multivariate regression analyses demonstrated that navigation-guided (odds ratio [OR]: 2.6, 95% confidence Interval [CI]: [1.75-4.07], p < 0.001) and manual (OR: 2.0, 95% CI: [1.34-3.20], p = 0.001) procedures were associated with an increased use of polyethylene liners 15 mm or greater. Robotic-assisted TKA was associated with a lower proportion of polyethylene liners 15 mm or greater used compared to navigation-guided and manual TKA. These findings suggest that robotic assistance can reduce human error via a more precise cutting system, limit over-resection of the tibia and flexion-extension gap mismatchand ultimately allow for more appropriately sized implants. Level III, retrospective cohort study.

Can Robotic Arm-assisted Total Knee Arthroplasty Remain Cost-effective in Volume-based Procurement System in China? A Markov Model-based Study.

The volume based procurement (VBP) program in China was initiated in 2022. The cost-effectiveness of robotic arm assisted total knee arthroplasty is yet uncertain after the initiation of the program. The objective of the study was to investigate the cost-effectiveness of robotic arm-assisted total knee arthroplasty and the influence of the VBP program to its cost-effectiveness in China. The study was a Markov model-based cost-effectiveness study. Cases of primary total knee arthroplasty from January 2019 to December 2021 were included retrospectively. A Markov model was developed to simulate patients with advanced knee osteoarthritis. Manual and robotic arm-assisted total knee arthroplasties were compared for cost-effectiveness before and after the engagement of the VBP program in China. Probability and sensitivity analysis were conducted. Robotic arm-assisted total knee arthroplasty showed better recovery and lower revision rates before and after initiation of the VBP program. Robotic arm-based TKA was superior to manual total knee arthroplasty, with an increased effectiveness of 0.26 (16.87 vs 16.61) before and 0.52 (16.96 vs 16.43) after the application of Volume-based procurement, respectively. The procedure is more cost-effective in the new procurement system (17.13 vs 16.89). Costs of manual or robotic arm-assisted TKA were the most sensitive parameters in our model. Based on previous and current medical charging systems in China, robotic arm-assisted total knee arthroplasty is a more cost-effective procedure compared to traditional manual total knee arthroplasty. As the volume-based procurement VBP program shows, the procedure can be more cost-effective.

Patients undergoing robotic arm-assisted total knee arthroplasty have a greater improvement in knee-specific pain but not in function.

The aim was to assess whether robotic-assisted total knee arthroplasty (rTKA) had greater knee-specific outcomes, improved fulfilment of expectations, health-related quality of life (HRQoL), and patient satisfaction when compared with manual TKA (mTKA). A randomized controlled trial was undertaken (May 2019 to December 2021), and patients were allocated to either mTKA or rTKA. A total of 100 patients were randomized, 50 to each group, of whom 43 rTKA and 38 mTKA patients were available for review at 12 months following surgery. There were no statistically significant preoperative differences between the groups. The minimal clinically important difference in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score was defined as 7.5 points. There were no clinically or statistically significant differences between the knee-specific measures (WOMAC, Oxford Knee Score (OKS), Forgotten Joint Score (FJS)) or HRQoL measures (EuroQol five-dimension questionnaire (EQ-5D) and EuroQol visual analogue scale (EQ-VAS)) at 12 months between the groups. However, the rTKA group had significantly (p = 0.029) greater improvements in the WOMAC pain component (mean difference 9.7, 95% confidence interval (CI) 1.0 to 18.4) over the postoperative period (two, six, and 12 months), which was clinically meaningful. This was not observed for function (p = 0.248) or total (p = 0.147) WOMAC scores. The rTKA group was significantly (p = 0.039) more likely to have expectation of 'Relief of daytime pain in the joint' when compared with the mTKA group. There were no other significant differences in expectations met between the groups. There was no significant difference in patient satisfaction with their knee (p = 0.464), return to work (p = 0.464), activities (p = 0.293), or pain (p = 0.701). Patients undergoing rTKA had a clinically meaningful greater improvement in their knee pain over the first 12 months, and were more likely to have fulfilment of their expectation of daytime pain relief compared with patients undergoing mTKA. However, rTKA was not associated with a clinically significant greater knee-specific function or HRQoL, according to current definitions.

Comparison of surgical times of various total knee replacement techniques and assessment of learning curve of robotic total knee replacement: a retrospective study

Background: This study aims to compare the operating times of manual, computer-assisted and robotic- assisted TKA and to calculate the learning curve for image-less robotic-assisted TKA (RATKA). Methods: This retrospective observational study, conducted at the Centre of Excellence, Bone, Joint and Spine, Meitra Hospital, Kozhikode, Kerala, India, focused on patients aged 60 and above undergoing total knee replacement for stage 4 osteoarthritis. The study included 75 consecutive cases of manual, computer- assisted, and robotic-assisted unilateral total knee arthroplasties performed between May 2021 and September 2022 (18 months). Data was collected from the hospital records. Results: The surgeon transitioned from learning to proficiency phase of RATKA after 14 cases. In the robotic learning phase, the overall operative time was 113.14 minutes (±8.96), significantly longer than the robotic proficiency phase's average of 98.24 minutes (±2.98) and that of CATKA (99.57±10.700 minutes) and manual TKAs (97.01±7.17 minutes). No statistically significant difference was observed in the global operative time between the proficiency phase RATKAs and the CATKA and manual groups (p=0.139). Conclusions: By optimizing techniques and modifying workflow, one can swiftly overcome the initial learning curve of RATKA and achieve operating times comparable to manual TKA. To enhance efficiency and productivity, the study proposes a revised workflow modifying various rate limiting surgical steps.

The ROSA knee robotic system demonstrates superior precision in restoring joint line height and posterior condylar offset compared to conventional manual TKA: a retrospective case–control study

PurposeVariations in total knee arthroplasty (TKA) joint line height may lead to complications such as pain and altered joint mechanics, while posterior condylar offset (PCO) can influence knee stability.MethodsSingle-centre, single-surgeon retrospective analysis from December 2019 to May 2023 investigated primary unilateral TKA (Nexgen Legacy, Zimmer Biomet) in patients with knee osteoarthritis, using ROSA robotic system (raTKA) or conventional manual technique (mTKA). Joint line height and PCO were measured and compared in 182 raTKA and 144 mTKA patients.ResultsThe groups were matched in age (p = 0.847) and sex distribution (p = 0.2). Excellent interobserver agreement (ICC ≥ 0.9). RaTKA mean joint line height difference was − 0.0001 mm (± 3.48, 95% CI − 0.509, 0.509) (p = 0.523), − 0.951 mm for mTKA (± 4.33, 95% CI − 1.664, − 0.237) (p = 0.009). RaTKA mean PCO difference was 0.52 mm (± 2.45, 95% CI 0.160, 0.880) (p = 0.005), 1.15 mm for mTKA (± 4.01, 95% CI – 1.496, 1.818) (p < 0.001). Mean difference in joint line height of 0.95 mm between groups was significant (p = 0.027), and for PCO, it was 0.63 mm, demonstrating tendency towards significance (p = 0.08). Mean absolute value in joint line height difference between groups was not significant (p = 0.235) but highly significant for PCO (p < 0.001).ConclusionThe ROSA knee robotic system can more accurately restore joint line height and PCO compared to conventional manual TKA. The improved degree of precision raTKA offers may be a vehicle for better Patient-Reported Outcome Measures, but further correlational studies are required.

Robotic-arm assisted versus manual total knee arthroplasty: Functional gait analysis from a randomised controlled trial

The primary aim of this study was to assess whether measures of functional gait assessment were improved with robotic total knee arthroplasty (rTKA) when compared to manual TKA (mTKA). Gait analysis was performed as part of a randomised controlled trial. Walking and relaxed standing assessments were performed using an instrumented mat system. Spatiotemporal variables included gait cycle parameters, anteroposterior and lateral sway, and plantar pressure ratios. Measurements were recorded at pre-operative baseline and 12 months post-operatively. 100 patients were randomised, 50 to each group. Complete gait cycle data were available for 26 rTKA and 23 mTKA patients. Cadence and walking velocity showed overall improvements following surgery, with no difference between the two groups. In the operated limb, overall step and stride times decreased, while step and stride lengths increased. Subgroup analysis showed reduced propulsion time with rTKA, and decreased foot flat and mid stance times with mTKA. Lateral sway was decreased in the rTKA group. Plantar pressure ratios showed an overall increase in hindfoot loading on the operated limb, with no difference between the two groups. No other significant differences were identified between rTKA and mTKA at 12 months, and limitations may include statistical error. A small sample of the study cohort was followed up; analysis may represent the results of satisfied patients with well-functioning TKA. Further study could incorporate proprioceptive and 3D gait analysis techniques to analyse knee kinetics and kinematics with robotic surgery. Pressure mapping could further subdivide the plantar surfaces to explore any nuances in differential loading.

Comparative analysis of acute blood loss anemia in robotic assisted vs. manual instrumented total knee arthroplasty

IntroductionRobotic assisted total knee arthroplasty has become an increasingly popular technique over the past several years. Manual total knee arthroplasty can be associated with acute blood loss anemia. Instrumentation of the femoral canal with the alignment guide may in part contribute to this blood loss. Because the femoral canal is not entered during robotic assisted total knee arthroplasty, the blood loss may be lower compared to that seen in manual total knee arthroplasty. The purpose of this study was to determine if acute blood loss is greater in manually instrumented total knee arthroplasty versus robotic assisted total knee arthroplasty. Materials and methodsThis retrospective cohort study was performed in a large tertiary academic hospital network by two fellowship trained surgeons. Patients underwent either robotic assisted or manually instrumented total knee arthroplasty and were assessed for postoperative acute blood loss anemia, defined as hemoglobin <13 g/dL for males or <12 g/dL for females plus a 2 g/dL drop from preoperative levels, as well as postoperative drop in hemoglobin. ResultsA total of 75 patients were included in each study arm. There was no significant difference (p > 0.05) in postoperative hemoglobin in robotic assisted (2.1 g/dL) compared to manually instrumented total knee arthroplasty (2.1 g/dL). There was no significant difference in the incidence of postoperative acute blood loss anemia between robotic assisted (45 %) and manually instrumented total knee arthroplasty (39 %). Higher BMI and increased age were protective against postoperative drop in hemoglobin. These protective effects were not significant when controlling for confounding variables. Surgical time was significantly longer for robotic assisted (99 min) versus manually instrumented total knee arthroplasty (86 min) (p < 0.001). ConclusionsThere is no significant difference in acute blood loss when comparing patients undergoing robotic assisted and manually instrumented total knee arthroplasty.

Outcomes of Image-Free Robotic Assisted Total Knee Arthroplasty in Patients Who Have Valgus Knee Deformities

BackgroundValgus knee deformities pose a unique challenge in total knee arthroplasty (TKA) due to the complexity of achieving ligamentous balance and satisfactory alignment compared to varus or neutral deformities. Robotic-assisted (RA) TKA could aid in achieving improved component alignment and balance. MethodsWe retrospectively evaluated a matched cohort of patients to compare image-free RA-TKA (n = 44) versus conventional manual (CM) TKA (n = 30) techniques in patients who have valgus deformity of 5 to 15 degrees, including radiographic and patient-reported outcomes measures (PROMs) over a 3-year period. The patient reported outcome measures (PROMs) studied to determine outcomes were: Western Ontario McMaster University Arthritis Index, Knee Society Score-Function Score, and Short Form 12-item Survey. ResultsOverall, the RA-TKA cohort showed faster improvement in PROMs (37.16 ± 1 8.8 versus 25.74 ± 17.7, P = .02), shorter length of stay (1.41 versus 2.29 days, P = .02), and shorter operating room times (120.79 versus 123.67 minutes, P = .02) than CM-TK). Additionally, there was no difference in the use of primary versus varus-valgus constrained polyethylene liners between the cohorts. ConclusionsIn this investigation, RA-TKA yielded a slightly faster patient recovery, more objective measurements of ligamentous balance, and proved noninferior PROMs compared to CM-TKA for preoperative valgus knee deformities.

Robot-assisted partial knee replacement versus standard total knee replacement (RoboKnees): a protocol for a pilot randomized controlled trial

BackgroundTotal knee arthroplasty is a common surgery for end-stage knee osteoarthritis. Partial knee arthroplasty is also a treatment option for patients with arthritis present in only one or two knee compartments. Partial knee arthroplasty can preserve the natural knee biomechanics, but these replacements may not last as long as total knee replacements. Robotic-assisted orthopedic techniques can help facilitate partial knee replacements, increasing accuracy and precision. This trial will investigate the feasibility and assess clinical outcomes for a larger definitive trial.MethodsThis is a protocol for an ongoing parallel randomized pilot trial of 64 patients with uni- or bicompartmental knee arthritis. Patients are randomized to either receive robot-assisted partial knee arthroplasty or manual total knee arthroplasty. The primary outcome of this pilot is investigating the feasibility of a larger trial. Secondary (clinical) outcomes include joint awareness, return to activities, knee function, patient global impression of change, persistent post-surgical pain, re-operations, resource utilization and cost-effectiveness, health-related quality of life, radiographic alignment, knee kinematics during walking gait, and complications up to 24 months post-surgery.DiscussionThe RoboKnees pilot study is the first step in determining the outcome of robot-assisted partial knee replacements. Conclusions from this study will be used to design future large-scale trials. This study will inform surgeons about the potential benefits of robot-assisted partial knee replacements.Trial registrationThis study was prospectively registered on clinicaltrials.gov (identifier: NCT04378049) on 4 May 2020, before the first patient was randomized.

Variability of the femoral mechanical-anatomical axis angle and its implications in primary and revision total knee arthroplasty.

Distal femoral resection in conventional total knee arthroplasty (TKA) utilizes an intramedullary guide to determine coronal alignment, commonly planned for 5° of valgus. However, a standard 5° resection angle may contribute to malalignment in patients with variability in the femoral anatomical and mechanical axis angle. The purpose of the study was to leverage deep learning (DL) to measure the femoral mechanical-anatomical axis angle (FMAA) in a heterogeneous cohort. Patients with full-limb radiographs from the Osteoarthritis Initiative were included. A DL workflow was created to measure the FMAA and validated against human measurements. To reflect potential intramedullary guide placement during manual TKA, two different FMAAs were calculated either using a line approximating the entire diaphyseal shaft, and a line connecting the apex of the femoral intercondylar sulcus to the centre of the diaphysis. The proportion of FMAAs outside a range of 5.0° (SD 2.0°) was calculated for both definitions, and FMAA was compared using univariate analyses across sex, BMI, knee alignment, and femur length. The algorithm measured 1,078 radiographs at a rate of 12.6 s/image (2,156 unique measurements in 3.8 hours). There was no significant difference or bias between reader and algorithm measurements for the FMAA (p = 0.130 to 0.563). The FMAA was 6.3° (SD 1.0°; 25% outside range of 5.0° (SD 2.0°)) using definition one and 4.6° (SD 1.3°; 13% outside range of 5.0° (SD 2.0°)) using definition two. Differences between males and females were observed using definition two (males more valgus; p < 0.001). We developed a rapid and accurate DL tool to quantify the FMAA. Considerable variation with different measurement approaches for the FMAA supports that patient-specific anatomy and surgeon-dependent technique must be accounted for when correcting for the FMAA using an intramedullary guide. The angle between the mechanical and anatomical axes of the femur fell outside the range of 5.0° (SD 2.0°) for nearly a quarter of patients.

Pitfalls with the MAKO Robotic-Arm-Assisted Total Knee Arthroplasty.

Robotic-arm-assisted total knee arthroplasty (RATKA) with the MAKO system minimizes deviations in implant alignment and yields superior precision in implant position compared to a manual total knee arthroplasty. In this comprehensive commentary, we present and categorize the limitations and pitfalls of the procedure and we also provide recommendations for avoiding each limitation. The main surgeon-related limitations include prolonged operation duration, loose insertion of the checkpoints and pins, wrong registration and mapping, and damage to soft tissues during bone cutting. The system-related issues include the interruptions of the saw-cutting due to vibrations, specifications for the operating room floor and power supply, the high cost of the system, as well as the cost of each operation due to the extra implants, inability to use the system with various prostheses, wireless connection interruptions between the system's components, and hardware issues with the six joints of the robotic device. In order to circumvent the potential challenges in this surgical procedure, it is essential to possess sufficient experience and undergo comprehensive training. Maintaining continuous awareness of the additional implants throughout the entire operation and prioritizing the preservation of soft tissues are of paramount significance. A profound comprehension of the system and its inherent constraints can also prove to be pivotal in certain situations.

Robotic-assisted total knee arthroplasty results in decreased incidence of anterior femoral notching compared to posterior referenced instrumented total knee arthroplasty.

Periprosthetic fracture (PPF) is an uncommon but devastating complication after total knee arthroplasty (TKA). Anterior femoral notching (AFN) is one of a perioperative risk factor for PPF. The main purpose of this study was to compare between the rates of anterior femoral notching (AFN) and supracondylar periprosthetic femoral fracture (sPPF) of manual TKA and robotic arm-assisted TKA (RATKA). Meanwhile, blood loss, transfusion rates, inflammatory responses, complications, early clinical and radiological outcomes were also assessed. This retrospective study included 330 patients (133 RATKA and 197 manual TKA). Differences in risks of inflammatory, blood loss, complications (periprosthetic fracture and periprosthetic joint infection), pre-operative and post-operative distal lateral femoral angle (LDFA), distal femoral width (DFW), prosthesis-distal femoral width (PDFW) ratio, AFN, femoral component flexion angle (FCFA), peri-operative and post-operative functional outcomes between the RATKA and manual TKA groups were compared. The operation time and postoperative CRP level in the RATKA group was significantly longer and higher than that in the manual TKA group (p < .001). However, there was no significant difference in postoperative WBC level (p = .217), hemoglobin loss (p = .362), postoperative drainage (p = .836), and periprosthetic fracture (p = 1.000). There was no significant difference in LDFA (p > .05), DFW(p = .834), PDFW ratio (p = .089) and FCFA (p = .315) between the two groups, but the rate of AFN in the RATKA group was significantly lower than that in the manual TKA group (p < .05). There was no significant difference in ROM between the two groups on POD3, POD 90 and 1 year (p < .05), but the FJS-12 score in the RATKA group was higher than that in the manual TKA group on 1 year (p = .001). Robotic-assisted total knee arthroplasty can decrease the incidence of anterior femoral notching compared to posterior referenced instrumented total knee arthroplasty.