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Robot-assisted total knee arthroplasty (TKA) has proven to be successful in improving the accuracy of component positioning and reducing radiographic outliers. This study aimed to evaluate and compare the alignment of the components using two- and three-dimensional (2D and 3D) measurements following handheld imageless robot-assisted TKA. Seventy consecutive patients underwent primary TKA at our institution using a handheld robot-assisted system. Full-length standing anteroposterior and lateral radiographs were obtained 2 weeks after surgery for assessment of 2D component alignments. Pre- and postoperative computed tomography (CT) images were obtained to assess 3D component alignment. The reference points defined on preoperative CT images were transferred to the postoperative CT images. The absolute errors in the 2D and 3D component alignments from the planned, validated cutting, and validated implantation angles were calculated. Outliers of >  ± 3° of femoral and tibial component alignments in the coronal and sagittal planes were also investigated. All absolute errors in the 2D and 3D component alignments were < 1°, except for the planned and validated cutting angles of the femoral sagittal alignment. No outliers were observed in the femoral or tibial component in the coronal plane. Significant differences between the 2D and 3D measurements were observed for the mean absolute value from the planned and validated cutting angles in the femoral sagittal plane and from the validated implantation angle in the tibial coronal plane. The handheld robot-assisted system demonstrated a high accuracy for component alignment using 2D and 3D evaluations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag London Ltd., part of Springer Nature.)

This study aimed to compare the cutting and component placement accuracies and early outcomes after total knee arthroplasty (TKA) between an image-free handheld robotic system (NAVIO) and a radiography-based robotic system (ROSA). This retrospective study included 88 patients (88 knees) who underwent TKA using the NAVIO (40 patients) or ROSA (48 patients) robotic systems. The accuracies of the robotic systems were compared. Clinical scores were evaluated using the Knee Society Score 2011 (KSS 2011) and the forgotten joint score (FJS)-12 at 1 year postoperatively. The femoral sagittal cutting error was smaller in the NAVIO group than in the ROSA group. The other cutting errors were not statistically different in both groups. Implantation errors did not differ between the groups. Regarding the clinical outcomes of the KSS 2011 subscales, the symptoms score was higher in knees operated using ROSA than in those using NAVIO. The other KSS 2011 subscales and the FJS-12 showed no differences between the two groups. In conclusion, the femoral sagittal cutting error was smaller in the NAVIO group than in the ROSA group, and the KSS 2011 symptom score subsection at one year was higher in the knees operated using ROSA than in those using NAVIO., (© 2024. The Author(s).)

Objectives: The objective of the study is to evaluate the relationship between clinical results following posterior-stabilized total knee arthroplasty (TKA) and intraoperative kinematic pattern determined from navigation., Methods: Participants were patients with knee osteoarthritis and varus deformity who underwent primary posterior-stabilized TKA. Preoperative and post-implantation kinematic data were recorded, and all kinematic patterns were divided into two types: medial pivot (MP) or non-MP. Knees with MP and non-MP patterns after implantation were compared in terms of postoperative flexion angle, pain, patient satisfaction, expectations, and activity using the new Knee Society Score 2011 at 1 year postoperatively., Results: This study involved 55 patients (12 men, 43 women) with a mean age of 73.1 years and mean body mass index of 26.5 kg/m2. Preoperative kinematic measurements showed MP in 23 knees and non-MP in 32 knees. After implantation, navigation showed MP in 25 knees and non-MP in 30 knees. No significant differences were found between kinematic patterns preoperatively and after implantation. Postoperative flexion angle, pain, patient satisfaction, expectations, and activity using Knee Society Score 2011 showed no differences between MP and non-MP knees., Conclusion: Intraoperative knee kinematics as measured by navigation could not predict postoperative outcomes of TKA., (© Japan College of Rheumatology 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

To clarify the association between pre- and postoperative rotational mismatches of the femorotibial components and bones for total knee arthroplasty (TKA) with bi-cruciate retaining (BCR) design and with fixed bearing posterior stabilized (PS) design. This retrospective cohort study included 40 BCR TKAs and 50 PS TKAs. Pre- and postoperative rotational mismatches of the femorotibial components and bones were measured by three-dimensional assessment based on computed tomography imaging. The mean value and percentage within ± 5° of pre- and postoperative rotational mismatches were compared between BCR TKA and PS TKA. Correlations between pre- and postoperative rotational mismatches of the femorotibial components and bones were investigated in BCR TKA and PS TKA. There was no significant difference in mean preoperative rotational mismatch of femorotibial components and bones between BCR TKA and PS TKA. Mean postoperative rotational mismatch of femorotibial components and bones was significantly greater in BCR TKA than in PS TKA. Postoperative rotational mismatch of the femorotibial components was within ± 5° in 21 knees (52.5%) for BCR TKA and in 43 knees (86.0%) for PS TKA. The rate of postoperative rotational mismatch of the femorotibial components and bones within ± 5° was significantly lower for BCR TKA than for PS TKA. In BCR TKA, there was a positive correlation between pre- and postoperative rotational mismatches of the femorotibial components and of bones. We consider these results can be attributed to the retention of both cruciate ligaments, which may affect the reduction of rotational permittance of the components and bones., (© 2023. Springer Nature Limited.)

Purpose: The primary aim was to evaluate the accuracy of navigation in opening wedge high tibial osteotomy (HTO). The secondary aim was to examine mid-term outcomes after HTO., Methods: Inclusion criteria were patients with medial compartment knee osteoarthritis who underwent computer-assisted HTOs. Mechanical axis (MA), percentage MA (%MA), and change in posterior tibial slope (ΔPTS) were displayed on the navigation screen. Radiographic examinations included hip-knee-ankle (HKA) angle, medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), and PTS. Preoperative and 5 weeks postoperative standing radiographs of the whole lower extremity and knee were used. Clinical evaluations were performed using American Knee Society knee score and function score both preoperatively and at last follow-up. Radiographic evaluations were performed by orthopedic surgeons. Intraoperative navigation after osteotomy and postoperative standing radiograph were compared. MA (HKA), %MA, and ΔPTS were compared. Outliers were defined as > 3° in MA, > 10% in %MA, and > 10° in ΔPTS. Outlier and non-outlier groups were compared. The rate of conversion to arthroplasty was examined., Results: This study involved 38 patients (44 knees) and last follow-up was at a mean of 5 years (range, 1-9 years). Mean American Knee Society knee score and function score improved significantly from 59 to 69 preoperatively to 95 and 85 at last follow-up, respectively. Absolute values of mean errors for MA, %MA, and ΔPTS were 2.1°, 9.3%, 1.2°, respectively. Outlier rates were 18% in MA, 39% in %MA, and 5% in ΔPTS. No significant factors were found in MA and ΔPTS. In %MA, preoperative JLCA was significantly higher in the outlier group compared to the non-outlier group. No knees underwent conversion to total knee arthroplasty. No differences in outcomes were found between outlier and non-outlier groups., Conclusion: Although rates of outlier values in computer-assisted opening wedge HTO were high, mid-term outcomes were excellent., Level of Evidence: IV., (© 2021. The Author(s), under exclusive licence to The Author(s) under exclusive licence to European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)

Background: The purpose of this study was to compare component alignment using two-dimensional (2D) and three-dimensional (3D) measurements following total knee arthroplasty (TKA) with a new robotic system., Methods: A total of 38 patients underwent TKA with the robotic system. Cutting errors were measured. Errors in 2D and 3D component alignments from the planned angle, validated cutting angle, and validated implantation angle were calculated. These errors were compared with 2D and 3D measurements., Results: Cutting errors were below 0.6°, except for femoral sagittal angle (1.0°). Errors in component alignment from the planned and cutting angles were significantly higher in 3D measurements than that in 2D measurements, in the femoral coronal and sagittal planes and tibial coronal planes. Errors in component alignments from implantation showed no differences between the measurements., Conclusion: The accuracies of component alignment from the planned and cutting angles were better in 3D measurements., (© 2022 John Wiley & Sons Ltd.)

Backgrounds: Preoperative widespread pain sensitization or pain catastrophizing could be associated with chronic pain after total knee arthroplasty (TKA). The aim of the present study was to examine the association between postoperative pain in patients undergoing TKA and preoperative factors, including patient characteristics and preoperative central sensitization as well as pain catastrophizing., Methods: Preoperative TKA patients were evaluated using the Central Sensitization Inventory (CSI)-9 and Pain Catastrophizing Scale (PCS). Postoperative knee pain was evaluated using a numerical rating scale (NRS) 6 months after TKA. Statistical analyses were performed to assess the relationship between NRS 6 months after TKA and preoperative factors, including patient characteristics, CSI-9, and PCS., Results: We enrolled 58 consecutive patients with osteoarthritis who underwent TKA. Using cutoff of 14, postoperative NRS was higher in the patients with ≥14 than the patients with <14 in CSI (p = 0.025). Postoperative NRS was higher in the patients with ≥30 than the patients with <30 in PCS (p = 0.043). Preoperative PCS was a significant risk factor of postoperative pain using a multivariate analysis., Conclusions: Surgeon should recognize preoperative PCS could affect postoperative pain 6 months after TKA., Competing Interests: Declaration of competing interest None., (Copyright © 2021 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Background: Patient satisfaction and expectations are now recognized as an outcome measure for successful total knee arthroplasty (TKA). The purpose of this study was to determine which factors including soft tissue balance during surgery affect patient satisfaction and expectations after TKA., Methods: A total of 135 patients (157 knees) with knee osteoarthritis who underwent primary TKA with a posterior stabilized design were studied. After implantation of all components, varus/valgus laxity of the knee was measured intraoperatively with the knee at 0°, 30°, 60°, 90°, and 120° guided by an image-free navigation system. Factors that affected patient satisfaction and expectations, including lateral and medial laxities, were evaluated using the 2011 Knee Society score., Results: The mean intraoperative lateral laxity was 1.1°, 1.6°, 0.9°, 1.3°, and 1.7° with the knee at 0°, 30°, 60°, 90°, and 120°, respectively. The mean intraoperative medial laxity was 1.1°, 1.4°, 1.1°, 1.1°, and 1.7° with the knee at 0°, 30°, 60°, 90°, and 120°, respectively. Patient satisfaction after TKA correlated positively with symptom (R = 0.61, p < 0.01) and functional activity (R = 0.47, p < 0.01) scores. Patient expectations after TKA weakly positively correlated with symptom (R = 0.29, p < 0.01) and functional activity (R = 0.20, p = 0.01) scores, and weakly negatively with medial laxity at 30° (R = -0.21, p < 0.01)., Conclusion: Midflexion medial laxity was associated with worse patient expectations after TKA. Avoiding medial laxity could be one of the important techniques during TKA.

Objectives: Antibiotic-impregnated hydroxyapatite (HA) is an emerging drug delivery system for the treatment of periprosthetic joint infection (PJI) of the knee. The aim of this study was to evaluate the clinical results of this treatment in patients with PJI following total knee arthroplasty (TKA)., Methods: Participants comprised 14 consecutive patients with PJI of the knee who were scheduled to undergo two-stage knee revision. In the first stage, all components were removed with thorough debridement, and antibiotic-impregnated HA was inserted in the bone and joint space. In the second stage, revision TKA was performed after the eradication of infection. The mean period from the removal of all components and treatment with antibiotic-impregnated HA to revision TKA was 3.4 months. Clinical and radiographic evaluations were performed after a mean follow-up of 6.1 years following revision TKA. Predictors of reinfection were evaluated., Results: Eleven patients had no recurrent infection, whereas 3 patients showed recurrent infection. Knee Society knee score and function score, as well as flexion angles, improved significantly postoperatively. No knees showed osteolysis or loosening after revision TKA. The present study identified no predictors of reinfection., Conclusion: Antibiotic-impregnated HA could be effective in treating knee PJI.

Background: Patellar tendon rupture is a devastating complication after total knee arthroplasty (TKA). Different strategies have been used to reconstruct or augment direct repairs., Methods: Acute patellar tendon ruptures after TKA were treated using ultra-high molecular weight polyethylene cable (Nesplon cable) for augmentation in four patients. Nesplon cables were inserted anteriorly through the quadriceps just above the patella, and drill holes were placed in the tibial tubercle with one in figure-of-eight fashion and the other in cerclage configuration. Clinical evaluations were performed using range of motion and Knee Society Score at the time of last follow-up. Mean follow-up was 3.5 years., Results: Postoperatively, mean flexion was 119° and mean extension was 0° in all cases. No knees showed extension lag. Mean knee score was 93.8 and mean function score was 63.8. Infection occurred in one case., Conclusion: Patellar tendon reconstruction with Nesplon cable was favorable with good clinical outcomes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Bleeding is a life-threating side effect of thromboprophylaxis with fondaparinux sodium (FPX) injection. The purpose of this retrospective study was to assess the risk factor for bleeding-related event following thromboprophylaxis with FPX after total knee arthroplasty (TKA) or total hip arthroplasty (THA). Adult patients undergoing TKA or THA at a single university hospital were administered FPX for thromboprophylaxis by subcutaneous injection of 1.5 or 2.5 mg per day. The risk factor for bleeding-related event was identified by propensity score-adjusted multivariate logistic analysis, and survival analysis was performed retrospectively in consideration of the identified risk factors. Two hundred and twenty-six patients who underwent TKA (n = 62) or THA (n = 164) were enrolled. Anaemia on postoperative day (POD) 1 was identified as a risk factor for bleeding-related event (odds ratio: 3.75, 95% confidence interval: 1.02-24.5, p = 0.04). Eighty of 226 patients were selected using a propensity score matching and patients with anaemia on POD1 in this population had a significantly higher incidence of bleeding-related event than those without anaemia (p = 0.0016, Ghen-Breslow-Wilcoxon test; p = 0.0015, log-rank test). These results suggest that anaemia on POD1 is an independent risk factor for bleeding-related event following thromboprophylaxis with FPX after TKA or THA.

The present study aimed to define the prevalence of pain persisting after total knee arthroplasty (TKA) and determine the impact of neuropathic pain. Knee pain after TKA was evaluated in 154 patients (222 knees with osteoarthritis) using a numerical rating scale (NRS) and followed up for a mean of 4.7 years. The patients were classified according to whether they had no or mild pain (NRS ≤ 3), or moderate-to-severe pain (NRS > 3), and then assigned to groups with nociceptive, unclear, or neuropathic pain based on responses to painDETECT questionnaires. Risk factors for these types of pain were determined. The ratio of patients with moderate-to-severe pain was 28% (62 knees). Thirteen patients (21 knees; 9%) experienced unclear pain. Patients with moderate-to-severe or unclear pain had malalignment and lower Knee Society knee scores. In conclusion, a significant number of patients experienced moderate-to-severe and unclear pain after TKA. Moderate-to-severe pain was associated with unclear pain., Competing Interests: None., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

The purpose of this study was to determine which factors contribute to patient satisfaction and expectations after total knee arthroplasty (TKA). A total of 109 patients (130 knees) with knee osteoarthritis who underwent primary TKA with navigation were studied. Intraoperative mediolateral laxity was measured. The factors including mediolateral laxity that affected patient satisfaction and expectations were evaluated using the 2011 Knee Society Score. Patient satisfaction after TKA correlated positively with symptoms and functional activities, and negatively with old age in univariate analysis. Multivariate analysis showed that symptoms and functional activities remained statistically significant; however, old age showed no difference. Patient expectations after TKA correlated positively with symptoms and functional activities, and negatively with mediolateral laxity at 60 degrees in univariate analysis. Multivariate analysis showed that symptoms, functional activities, and mediolateral laxity at 60 degrees remained statistically significant. In conclusion, midflexion instability was associated with worse expectations., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Objectives: The objective of this retrospective study was to investigate the prevalence of asymptomatic deep vein thrombosis (DVT) and the risk of DVT in patients admitted to hospital for total knee arthroplasty (TKA)., Methods: From September of 2003 to December of 2013, 322 patients admitted for TKA were eligible for this retrospective study. A diagnosis of DVT was confirmed by Doppler ultrasonography. The prevalence of silent DVT in the lower limbs in patients before TKA was assessed. The risk factors for preoperative DVT were investigated, as well as the correlation of DVT in the patient's background and medical history., Results: Preoperative DVT was diagnosed in 56 patients (17.4%) including 3 patients with proximal DVT. Significantly elevated risks of DVT were found in patients undergoing revision TKA (p < 0.01), patients with rheumatoid arthritis (RA) (p < 0.005), patients with connective tissue diseases (CTDs) (p < 0.05), and female patients (p < 0.05) on univariate analyses. Multiple linear regression analysis showed that RA, CTDs and admission for revision TKA were independent risk factors for preoperative DVT., Conclusions: A high prevalence of preoperative DVT was found in patients admitted to hospital for TKA. Admission to the hospital for RA, CTDs and revision TKA were risk factors for preoperative DVT., (Copyright © 2017 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Although the introduction of highly cross-linked polyethylene is effective in reducing the amount of wear, there are still major concerns regarding the use of this material in total knee arthroplasty (TKA), essentially due to the reduction of fatigue resistance and toughness. Monitoring the in vivo performance of different types of UHMWPE is a much needed task to tackle the lack of information on which should be the most reliable choice for TKA. The present study was aimed at investigating the mid-term degradation of electron beam sterilized conventional UHMWPE tibial plates. Visual inspection enabled to grade the surface damage of 12 retrievals according to the Hood's score: the total wear damage correlates to the in vivo time (Spearman's ρ=0.681, p<0.05) and BMI (ρ=0.834, p<0.001). Surface degradation was less severe than that quantified in similar studies on γ-sterilized UHMWPE. Raman and infra-red spectroscopies were utilized to unfold the microstructural modifications. In the load zone, polyethylene whitened damage regions were noticed in the inserts implanted longer than 1year, in which oxidation index (OI) is clearly higher than 1 (max 8). The maximum OI (ρ=0.802, p<0.005) and α c (ρ=0.816, p<0.005) correlate to the implantation time in the load zone. The crystallinity increased along with the extent of oxidation. Concentration of absorbed species from synovial fluid is higher in the contact zone and correlates to maximum OI (Spearman's ρ=0.699, p=0.011). Absorption was promoted in the contact area by the mechanical action of the femoral counterpart and it exacerbated the oxidative degradation in retrievals with high concentration of absorbed species. In the non-load zone, mild but detectable oxidation was observed, probably due to free radicals trapped after sterilization., Statement of Significance: Although several clinical studies on retrieved tibial bearings have been published so far, monitoring and comparing the in vivo performance of different types of UHMWPE is still a much needed task. The present study reports for the first time results on the effect of sterilization by electron beam on the mid-term in vivo performance of conventional UHMWPE tibial plates. In the present investigation, visual inspection of wear damage based on the Hood's scoring method, Raman micro-spectroscopy and Fourier-transformed infrared spectroscopy were utilized to unveil the damage, the microstructural modifications and the oxidation occurred during implantation. The findings of this investigation have been discussed and compared to previous clinical studies on γ-air sterilized, γ-inert sterilized tibial bearings., (Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Background: Minimally invasive surgery (MIS) has perceived advantages in the early postoperative stage for total knee arthroplasty (TKA). It is not clear whether the improved radiographic alignment achieved by computer-assisted navigation surgery (CAS) improves midterm clinical outcomes. The aim of this study was to compare patient outcomes of MIS TKA performed with and without CAS after a minimum follow-up of 7 years., Methods: Between 2007 and 2009, 50 patients underwent CAS and MIS TKA, and 50 patients underwent jig-based MIS TKA in this prospective study. Ninety-six patients were evaluated after a mean follow-up of 7.7 years, and clinical and radiological evaluations were performed., Results: Midterm results demonstrated that the Knee Society knee score, function score, and range of motion were comparable in the 2 groups. The percentage of patients with the mechanical axis within ±3° of neutral was significantly higher in the CAS group than in the jig-based group (94% vs 79%, respectively; P = .038). No knees had loosening after TKA. However, 1 patient in the CAS group demonstrated late infection 4 years postoperatively., Conclusion: CAS did not improve midterm outcomes after MIS TKA compared with jig-based surgery, although CAS reduced outliers in coronal alignment., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Unlabelled: As a matter of fact, the in vivo oxidative degradation of highly cross-linked polyethylene (HXLPE) still remains one of the limiting factors that affect the long term survivorship of joint replacements. Recent studies clearly pointed out that also the new generation of highly cross-linked and remelted polyethylene components in total hip and knee replacement underwent unexpected oxidation after 5-10years of implantation. The standard methodology to investigate the oxidation of polyethylene (PE) relies on the use of infrared spectroscopy, which, if from one hand is a reliable technique for the detection of oxidized species containing carbonyl group, on the other hand it is not capable of discriminating the fraction of carboxyl acids that is responsible for chain scission and subsequent deterioration of the mechanical properties of the polymer. In the present study we validate a new protocol based on Raman spectroscopy, which is suitable on assessing the structural degradation of polyethylene induced by oxidation. Following in vitro accelerated aging experiments, the oxidation index (OI) of different commercially available HXLPEs, as calculated by infrared spectroscopy according to ASTM standard, has been univocally correlated to the most severe variation of crystalline phase (αc), as calculated by Raman spectroscopy. In each material, locations with equal values of OI showed different degree of recrystallization induced by chain scission, confirming that infrared spectroscopy might overestimate the effective mechanical degradation of the polymer. In addition, as compared to the standards based on infrared spectroscopy, this new method of assessing oxidation enables to investigate the degradation occurring on the original surface of HXLPE components, due to the nondestructive nature of Raman spectroscopy and its high spatial resolution., Statement of Significance: In the present study we validate a new protocol based on Raman spectroscopy, which is suitable on assessing the structural degradation of polyethylene induced by oxidation. In fact, the standard methodology to investigate the oxidation in polyethylene relies on the use of infrared spectroscopy, which is capable of detecting the presence of oxidized species containing carbonyl group, the main products of oxidation in polyolefins. If from one hand this technique enables quantitative analysis of oxidation, on the other hand it is not capable of discriminating the fraction of species with carbonyl groups responsible for the chain scission. In fact, esters, ketones and carboxyl acids are products of oxidation with carbonyl groups commonly formed on polyethylene at the end of the oxidative cascade initiated by the presence of free radicals, but only the latter are responsible for the chain scission and the subsequent deterioration of the mechanical properties. The oxidation index as obtained according to the ASTM standards is not univocally correlated to a certain degree of mechanical deterioration, but, in simple words, two retrievals with the same amount of carbonyl groups might have had different degradation of the mechanical properties. Recrystallization is a direct consequence of the reduction of molecular weight that occurs after chain scission. Raman spectroscopy (RS) is a viable non-destructive method to assess the fraction of crystalline phase in polyethylene and, due to its high spatial resolution, is perfectly suitable to analyze the microstructural modification at the mesoscopic scale, where the effects of oxidation manifest themselves. The aim of the present paper is twofold: i) to compare the microstructural modifications caused by in vitro oxidation on 5 different types of polyethylene currently available on the market of joint replacements; ii) to establish a protocol based on the comparative analysis of IR and RS results to obtain a phenomenological correlation capable to judge the mechanical deterioration of the material induced by the oxidative degradation., (Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

This study evaluated the influence of intra-operative soft tissue balance on post-operative range of motion in patients undergoing posterior-stabilized total knee arthroplasty with navigation. After implantation of all components in 31 consecutive patients, the joint component gap was measured manually with the knee at 0°, 90°, and 120° as guided by a navigation system. We designated soft tissue balance as the absolute difference between varus stress and valgus stress (medio-lateral laxity). Changes in medio-lateral laxity were calculated from 120° to 90°, 120° to 0°, and 90° to 0°. Correlations among post-operative flexion angles and pre-operative flexion angles, intra-operative flexion angle after implantation, soft tissue balance, and the changes were analyzed. The mean pre- and post-operative knee flexion angles were 114 ± 20° and 127 ± 9°, respectively. The mean intra-operative flexion angle was 137 ± 6°. The post-operative flexion angle was positively correlated with the pre-operative flexion angle and intra-operative flexion angle after implantation. The change in soft tissue balance between 120° and 90° showed a positive correlation with the post-operative flexion angle. In conclusion, Assessment of intra-operative soft tissue balance could predict post-operative flexion angle.

Background: The relationships among the hemostatic markers, the development of deep vein thrombosis (DVT) and the withdrawal of fondaparinux due to a reduction in the hemoglobin levels were examined., Methods: Two-hundred twenty-one Japanese patients who underwent major orthopedic surgery and were treated with 1.5mg of fondaparinux instead of 2.5mg of fondaparinux were studied. Forty-seven of 221 patients discontinued fondaparinux treatment (withdrawal group) and 37 patients developed DVT., Results: The age, frequency of total knee arthroplasty (TKA), withdrawal of fondaparinux, reduction of hemoglobin and the plasma levels of soluble fibrin (SF), D-dimer and fibrinogen and fibrin degradation product (FDP) on day 1 after the operation were significantly higher in the patients with DVT. Elevated SF, D-dimer or FDP levels were associated with the risk for DVT. The age, frequency of TKA or DVT, anti-Xa activity and the creatinine, FDP and D-dimer levels were significantly higher in the withdrawal group. An anti-Xa level >0.33 mg/l and an elevated D-dimer or FDP level were associated with the risk of withdrawal., Conclusion: The age and SF levels, TKA and withdrawal of fondaparinux were related to the risk of DVT, and the anti-Xa activity, creatinine level and DVT were related to the risk of withdrawal of fondaparinux due to a reduction in hemoglobin., (© 2013.)

Ambulation in the early postoperative period of total knee arthroplasty is crucial, in order to avoid complications and obtain preferable outcomes. Although a femoral nerve block can provide enough postoperative analgesia after total knee arthroplasty, falling, or other accidents due to motor paresis, are potentially adverse events in patients who have received a conventional femoral nerve block. We devised a modified femoral nerve block to spare voluntary knee extension ability, and clinically applied it to patients who received total knee arthroplasty under minimally invasive surgery. In our new-approach nerve blockade technique, the main targets of the sensory nerves are the saphenous nerves which branch out from the femoral nerve trunk. All the patients rated pain at bed rest between 0 and 3 on a numerical rating scale 3 h after the operation. In addition, the rectus femoris muscle was not affected at all, and the surgically invaded vastus medialis oblique muscle was completely anesthetized. Patients were able to not only actively raise their extremities with their knee in extension, but also to flex the knee in the air without pain or aggravation. On day 0, the patients were able to walk around, with the leg that had been operated upon not giving way. Our anesthetic approach can provide better pain relief than a conventional femoral nerve block, while the patients achieve ambulation on the day of the procedure, following minimally invasive knee surgery.

Purpose: The purpose of this study was to evaluate the accuracy of bone cutting and implantation in minimally invasive total knee arthroplasty with image-free navigation., Methods: The alignment of the tibial and femoral bone resection was measured in 40 knees during surgery. The alignment measurement was repeated after cementing the tibial and femoral components. We evaluated the cutting error and the implanting error., Results: The mean tibial cutting errors were 0.5 and 0.7° in the frontal and sagittal planes, respectively. The mean femoral cutting errors were 0.5 and 0.9° in the frontal and sagittal planes, respectively. The mean tibial implanting errors were 1.0 and 0.9° in the frontal and sagittal planes, respectively. The mean femoral implanting error was 0.7° in the frontal plane., Conclusions: Computer-assisted navigation was useful in checking the alignment of both bone cut and cementation.

The purpose of this paper is to report the use of total knee arthroplasty using a tumor prosthesis in the treatment of elderly patients with an intercondylar fracture of the distal femur. Supracondylar fractures of the femur in patients with rheumatoid arthritis are difficult to treat due to joint deformity. We present outcomes for treating intercondylar fractures of the distal femur in rheumatoid arthritis patient using a tumor endoprosthesis. This technique allows early mobilization of the patient, with restoration of a good range of knee motion. A tumor prosthesis appears to be a viable treatment option for intercondylar femoral fractures in elderly patients. It is well tolerated and permits early ambulation and return to activities of daily living.

Deep venous thrombosis (DVT) is a life-threatening postoperative complication and occurs frequently after total-knee-replacement arthroplasty (TKA) and total-hip-replacement arthroplasty (THA). Fondaparinux (FPX) has been used to treat and prevent DVT, however interindividual difference of the drug efficacy exists. Therefore, this chart review was retrospectively conducted to research risk factors for a residual DVT after FPX treatment. Total of 112 patients undergone TKA or THA were treated with 2.5 mg FPX once a day between postoperative day (POD) 1 and 14 from July 2007 through December 2008. Among these patients, 30 patients who were detected DVT on POD 4 were enrolled in this study. Thirty patients were divided into two groups according to the presence (n=11) or absence (n=19) of DVT on POD14. The DVT (-) group had a significantly longer activated partial thromboplastin time (APTT, median 31.4 s) on POD 1 than the DVT (+) group (28.5 s) (p<0.02). Multivariate logistic regression analysis revealed that APTT lower than 28.5 seconds on POD1 was considered to be independent risk factor significantly contributing to residual DVT (odds ratio 17.5, 95% confidential interval 2.0-295.4, p=0.02). These findings should provide useful information for understanding the interindividual difference of the efficacy of FPX after TKA or THA.

Recurrent hemarthrosis after knee arthroplasty can be disabling, requiring adequate and immediate diagnosis and treatment for recovery of symptoms and joint function. The most commonly reported cause is impingement of proliferative synovium between prosthetic components. Although various procedures for hemarthrosis have been reported after knee arthroplasty for patients who do not respond to conservative treatment, the recommended first-line therapy is open surgery or embolization. Although hyperplastic synovium was observed during the first and second arthrotomy, in our case, tissue impingement was not detected. We describe a rare case of recurrent hemarthrosis after unicompartmental knee arthroplasty (UKA) and successful treatment by open synovectomy. A 66-year-old woman presented with spontaneous osteonecrosis of the medial femoral condyle in the right leg. She underwent UKA of the right knee of the medial condyle. Eighteen months after UKA, the patient developed recurrent hemarthrosis. Open arthrotomy was performed 22 months after UKA, revealing only hematoma with no obvious hemorrhage or loosening of the prosthesis. No history of trauma or use of anticoagulant medications was present. After a symptom-free period of 8 months, another 2 episodes of hemarthrosis occurred over the course of 8 months. A second open arthrotomy was performed. Hyperplastic synovium with fibrin and hemosiderin pigmentation was observed, again without hemorrhage or loosening. There were no pathological features of pigmented villonodular synovitis. Synovectomy was performed, and no hemarthrosis has recurred for 2 years., (Copyright 2011, SLACK Incorporated.)

Purpose: Correct alignment of the leg and positioning of the components are important factors in good long-term outcome of total knee arthroplasty (TKA). Computer-assisted navigation systems were introduced to improve component alignment accuracies. The three main hypotheses of this study were that the navigated compared to jig-based patient will show the following: (1) No difference in clinical outcomes. (2) Better alignment in the frontal and sagittal plane. (3) Better rotational positioning of components., Methods: The authors evaluated 100 patients who had minimally invasive TKA using either an image-free computer-assisted navigation system (n=50) or a jig-based technique (n=50). Six months postoperatively, clinical and radiological evaluations were performed using full-length standing anteroposterior and lateral radiographs and CT scans of the knee., Results: Knee Society knee score, function score, and range of motion were comparable in the two groups after surgery. The percentage of patients with a frontal tibiofemoral angle within ±3° of the ideal was significantly higher in the navigated group than in the jig-based group (94% vs. 78%, respectively; P=0.041). No significant differences were found between groups in terms of the frontal and sagittal planes as well as rotational alignment of the femoral or tibial components., Conclusion: Computer-assisted TKA gives a better correction of alignment of the leg compared with jig-based TKA when combined with a minimally invasive surgical approach.

Standard surgical exposure reduces blood flow to the patella during total knee arthroplasty (TKA). Reduction of patellar blood flow has resulted in patellofemoral complications including osteonecrosis and patellar fracture, necessitating revision surgery. In TKA, avoiding patellar eversion is one type of minimally invasive surgery (MIS) technique. This study is the first to measure patellar blood flow during MIS TKA with the knee in both extension and 90 degrees of flexion followed by lateral retraction and then eversion of the patella. Patellar blood flow was measured using laser Doppler flowmetry in 40 patients during MIS TKA. A significant reduction in flow was noted when the leg was flexed from full extension to 90 degrees . Eversion of the patella reduced patellar blood flow. MIS TKA without patellar eversion may be useful for preventing a reduction in patellar blood flow.

Ochronotic arthropathy is a manifestation of long-standing alkaptonuria, a rare hereditary metabolic disorder characterized by the absence of the enzyme homogentisic acid oxidase. We describe a patient who developed rapidly progressive destructive ochronotic arthropathy in his knee and hip joints and underwent successful bilateral total knee and hip arthroplasties.

Mobile-bearing total knee arthroplasty (TKA) has several theoretical advantages over fixed-bearing TKA. We conducted a prospective randomized trial to compare the results of mobile-bearing and fixed-bearing posterior-stabilized TKA in the same patients using the same femoral component design of a mobile-bearing prosthesis in one knee and a fixed-bearing prosthesis in the other knee in 25 patients with osteoarthritis. The mean follow-up was 40 months. No significant differences were found in the mobile-bearing and fixed-bearing knees in terms of clinical and radiographic results. No osteolysis, loosening, or revision occurred. One knee with a mobile-bearing prosthesis had a dislocation of the rotating bearing; however, spontaneous reduction occurred and the dislocation did not recur. Satisfactory early results can be achieved in both mobile-bearing and fixed-bearing knees. We could not demonstrate an advantage of a mobile-bearing TKA.

Osteogenesis imperfecta (OI) is a rare congenital disorder of type capital I, Ukrainian collagen production that results in brittle bones and affects body systems containing collagen. The increasing life span of patients with OI has recently revealed a high incidence of osteoarthritis of the knee. A 53 year-old man with OI presented with bilateral knee pain. He had severe deformities of the proximal part of the femur with subsegment post-traumatic osteoarthritis of both sides of the knees. However, the frequency of fracture gradually decreased and he had not experienced a fracture for 17 years. His bone mineral density was extremely low for his age. He underwent cemented total knee arthroplasty (TKA) on the left knee. One year later, the patient had relief of pain and he could walk without assistance. To our knowledge, only three knee replacements in two patients with OI have been reported, so this case is extremely rare. Although whether a patient with OI is a suitable candidate for knee replacement, it was a useful treatment for osteoarthritis in this case.

Introduction: There is a great deal of controversy about the effect of tourniquets on development of deep vein thrombosis (DVT) after total knee arthroplasty (TKA)., Patients and Methods: We investigated the incidence of postoperative DVT after TKA with or without the use of a tourniquet. The patients were 48 consecutive patients undergoing primary ipsilateral cemented TKA for osteoarthritis. Group A (21 patients) underwent the operation without a tourniquet, and Group B (27 patients) underwent the operation with a tourniquet. Ultrasonography to assess DVT was performed before and after the operation., Results: Group B had less intraoperative and total blood loss than Group A. Postoperative DVT was detected in 81.3% of all cases, and symptomatic pulmonary embolism occurred in 1.7%. Most of DVT was found in the calf vein. There was no significant difference in the incidence of postoperative DVT between the two groups., Conclusion: We conclude that the use of a tourniquet is beneficial, because it decreases perioperative blood loss and does not increase the risk of DVT. The incidence of DVT after TKA is considerably high with or without use of a tourniquet. Therefore, prevention and early detection of DVT are important for prevention of fatal pulmonary thromboembolism.

Introduction: A symptomatic cyst is an uncommon complication after total knee arthroplasty (TKA). We present a case of a 77-year-old woman with a large cyst in the right knee caused by metal wear debris from the failure of a Miller-Galante I TKA performed 13 years earlier., Case Presentation: The patient was treated with a two-stage operation including revision of the TKA followed by excision of the cyst, because there was a direct communication between the joint cavity and the cyst, and because the patient reported pain corresponding to the cystic area after revision. The patient was pain-free and had a satisfactory result 17 months after the second operation, without recurrence of cyst formation., Conclusion: We recommend two-stage surgery in which the first-stage is correction of the intra-articular pathology with revision TKA and the second-stage is excision of the cyst.

Spin-out of mobile-bearing knees is a significant early complication of mobile-bearing total knee arthroplasty. Dislocation of the cam-post mechanism of fixed-bearing posterior-stabilized knees occurs more rarely. We have observed an unusual case of dislocation of posterior-stabilized rotating-platform total knee arthroplasty, which has both a cam-post mechanism and rotating platform. A 65-year-old man with knee osteoarthritis and cervical spondylotic myelopathy underwent total knee arthroplasty using a mobile-bearing prosthesis. The dislocation, which occurred 4 days postoperatively, could not be reduced by closed manipulation. However, spontaneous reduction occurred 6 days after the dislocation, which did not recur. A gap mismatch or trapezoidal-shaped gaps may lead to dislocation or spin-out of the bearing insert. This case illustrates that dislocation of a posterior-stabilized mobile-bearing total knee arthroplasty can occur, and both quadriceps deficiency and ligament laxity may contribute to the risk of dislocation.