Wide-range resistivity characterization of semiconductors with terahertz time-domain spectroscopy.

Resistivity is one of the most important characteristics in the semiconductor industry. The most common way to measure resistivity is the four-point probe method, which requires physical contact with the material under test. Terahertz time domain spectroscopy, a fast and non-destructive measurement method, is already well established in the characterization of dielectrics. In this work, we demonstrate the potential of two Drude model-based approaches to extract resistivity values from terahertz time-domain spectroscopy measurements of silicon in a wide range from about 10-3 Ωcm to 102 Ωcm. One method is an analytical approach and the other is an optimization approach. Four-point probe measurements are used as a reference. In addition, the spatial resistivity distribution is imaged by X-Y scanning of the samples to detect inhomogeneities in the doping distribution.

Patients risk for mortality at 90 days after proximal femur fracture - a retrospective study in a tertiary care hospital.

BACKGROUND: Despite improving the management of proximal femur fractures (PFF) with legal requirements of timing the surgery within 24 h, mortality rates in these patients remain still high. The objective of our study was to analyze potential cofactors which might influence the mortality rate within 90 days after surgery in PFF to avoid adverse events, loss of quality of life and high rates of mortality. METHODS: In this retrospective, single-center study all patients with PFF aged 65 years and older were included. We recorded gender, age, type of fracture, surgery and anesthesia, time, comorbidities and medication as well as complications and mortality rate at 90 days. Separate logistic regression models were used to assess which parameters were associated with patients' mortality. The mortality rate was neither associated with timing, time and type of surgery nor time and type of anesthesia, but with higher age (OR 1.08 per year; 95% CI 1.034-1.128), lower BMI (OR 0.915 per kg/m2; 95% CI 0.857-0.978), higher CCI (OR 1.170 per point; 95% CI 1.018-1.345), dementia (OR 2.805; 95% CI 1.616-4.869), non-surgical complications (OR 2.276; 95% CI 1.269-4.083) and if mobilization was impossible (OR 10.493; 95% CI 3.612-30.479). RESULTS: We analyzed a total of 734 patients (age ≥ 65 years) who had a PFF in 2019 and 2020 and received surgery. 129 patients (17.6%) died until 90 days at an median age of 89.7 years (range 65-101 years). CONCLUSION: The proportion of patients who died until 90 days after surgery is still high. It is less extend influenced by surgical and anaesthesiologic factors than by patient-related factors like age or lower BMI. Physicians should be aware of the importance of avoiding adverse events and the importance of patients' mobilization to reduce mortality and improve patients' outcome.

Better Flexion but Unaffected Satisfaction After Treatment With Posterior Stabilized Versus Cruciate Retaining Total Knee Arthroplasty - 2-year Results of a Prospective, Randomized Trial.

BACKGROUND: Both the cruciate-retaining (CR) and posterior-stabilized (PS) implant systems are commonplace in modern total knee arthroplasty (TKA) practice. However, there is controversy regarding functional outcomes and survivorship. The aim of the underlying study was to evaluate differences between CR and PS TKA regarding knee function, patient-reported outcome measures (PROMs) as well as complication rates. METHODS: 140 patients with knee osteoarthritis scheduled for an unconstrained TKA were enrolled in a prospective, randomized study. Patients received either a CR or PS implant. Range of motion and PROMs (Oxford Knee Score, Knee Society Score, European Quality of Life 5 Dimensions 3 Level, University of California Los Angeles Activity scale and subjective satisfaction) were assessed prior to, 3 months, 1 and 2 years after surgery. RESULTS: We found minor differences between treatment groups regarding demographic factors. Within the PS group duration of surgery was longer (mean PS 81.4 min vs CR 76.0 min, P = .006). We observed better flexion (median PS 120.0° vs CR 115°, P = .017) and an overall better range of motion (median PS 120.0° vs CR 115.0°, P = .008) for the PS group. PROMs did not differ between groups. At 2-year follow-up there were no revisions in either cohort. Five patients needed reoperations. Three patients needed manipulation under anesthesia, 2 in the CR and one in the PS group. CONCLUSION: While PS TKA achieved a better flexion capability, PROMs were similar in CR and PS TKA. The CR implant design continues to be a reliable option for patients with an intact posterior cruciate ligament.

Influence of bone density on stability in TBW.

Osteoporosis is a common disease that leads to a reduction in bone density and increases the risk of fractures. Stable surgical treatment is particularly important for these fractures. The aim of this study was to examine the influence of bone density in the area of ​​the proximal ulna on the failure of the fixation technique of K-wires in tension band wiring (TBW). We provided 10 ulna specimens with TBW and biomechanically examined the pull-out strength of bi- and tricortical K-wires. Bone density measurement was performed using qCT. In the paired t-test, the tricortical group showed a significantly higher pull-out strength in relation to bone density than the bicortical group (p = 0.001). Furthermore, the Pearson correlation showed a high influence of bone density on pull-out strength in the tricortical group (r = 0.544), but without significance (p = 0.100).Our work shows that bone density has a direct effect on the pull-out strength of K-wires in TBW. TBW should therefore be used as osteosynthesis technique, especially in young patients with non-osteoporotic bones. In the case of osteoporotic fractures, alternative procedures should be preferred.

No difference in patient reported outcome and inflammatory response after coated and uncoated total knee arthroplasty - a randomized controlled study.

BACKGROUND: Allergies against implant materials are still not fully understood. Despite controversies about its relevance, some patients need treatment with hypoallergenic implants. This study compared coated and standard total knee arthroplasty (TKA) regarding inflammatory response and patient-reported outcome measures (PROMs). METHODS: 76 patients without self-reported allergies against implant materials were included in a RCT and received a coated or standard TKA of the same cemented posterior-stabilized knee system. 73 patients completed the 3-year follow-up. Two patients died and there was one revision surgery. Serum levels of cytokines with a possible role in implant allergy were measured in patient`s serum (IL-1beta, IL-5, IL-6, IL-8, IL-10, IFN γ, TNF α) prior to, one and three years after surgery. Furthermore, PROMs including knee function (Oxford Knee Score, Knee Society Score) and health-related quality of life (QoL, EuroQuol questionnaire) were assessed. Additionally, 8 patients with patch-test proven skin allergy against implant materials who received the coated implant were assessed similarly and compared to a matched-pair group receiving the same implant. RESULTS: There were no differences in function and QoL between the assessed groups at any follow-up. The majority of patients demonstrated no elevation of the measured blood cytokines. Cytokine patterns showed no differences between study groups at any follow-up. The allergy patients demonstrated slower functional improvement and minor differences in cytokine pattern. Yet these results were not significant. There were no differences in the matched-pair analysis. CONCLUSION: We observed no relevant increase in serum cytokine levels in any group. The inflammatory response measured seems limited, even in allergy patients. Furthermore, there were no differences between coated and standard TKA in non-allergy patients in the 3-year Follow-Up period. TRIAL REGISTRATION: The study protocol was registered in the US National Institutes of Health's database ( http://www. CLINICALTRIALS: gov ) registry under NCT03424174 on 03/17/2016.

Fulfilment of patients' mandatory expectations are crucial for satisfaction: a study amongst 352 patients after total knee arthroplasty (TKA).

PURPOSE: Patient satisfaction with the results of their total knee arthroplasty (TKA) is one of the primary goals of this elective procedure. Furthermore, the association between the fulfilment of patients' expectations and their satisfaction is well known. The aim of this study was to identify the key expectations of patients awaiting a TKA, evaluate their fulfilment, and compare the outcomes between very and not fully satisfied patients. METHODS: A prospective cohort study of patients with knee OA scheduled for primary TKA was performed. Pre- and one-year postoperatively patient-reported outcome measures (PROMs) were assessed. Expectations and their fulfilment were evaluated via a questionnaire encompassing 31 expectations. Preoperatively, expectations were indicated as mandatory, desirable and not important. Postoperatively, fulfilment was rated as exceeded, fulfilled, partially or not fulfilled, and not applicable. Satisfaction with the results of TKA was measured with a numeric rating scale (NRS) of 0-10. Discrimination between not fully satisfied and very satisfied patients was set at ≥ 8, as has been proposed recently. To identify independent predictors of this discrimination, a multivariate logistic regression analysis was performed. RESULTS: Complete data sets of 352 patients were analysed. A set of 17 key expectations was identified. Relief of knee pain was fulfilled the most, and improvement of physical function was fulfilled the least. When asked about overall fulfilled expectations, 40% of patients rated them as exceeded, 34% as fulfilled and 26% as less fulfilled than expected. Not fully satisfied patients showed significantly lower PROMs pre- and postoperatively and less fulfilled key expectations. Higher numbers of exceeded and fulfilled mandatory expectations, higher overall fulfilment and better range of motion (ROM) were significant predictors for satisfaction ≥ 8. CONCLUSION: Patients' expectations of TKA outcomes were high with equal emphasis on knee-related and general health-related aspects. Their fulfilment was positively associated with satisfaction. Surgeons should ask patients about mandatory expectations for successful TKA and counsel them about the likelihood of their fulfilment to avoid unrealistic expectations. LEVEL OF EVIDENCE: II.

Increased inflammatory response is associated with less favorable functional results 5 years after total knee arthroplasty.

PURPOSE: Allergy against implant materials is discussed controversially and still not fully understood. Despite these controversies, a relevant number of patients receive hypoallergenic knee implants. The aim of this study was to compare a new coating system with the standard implant in total knee arthroplasty (TKA). Additionally, the influence of proinflammatory cytokines on patient-reported outcome measures (PROMs) was investigated. METHODS: 120 patients without known metal allergy and without previous metal implants were included. The patients were randomized to receive a coated or standard TKA of the same knee system. 105 patients completed the 5 year follow-up. Patient-reported outcome measures (PROMs) including knee function (Oxford Knee Score, OKS), quality of life (SF36) and UCLA activity scale were assessed. Additionally, several cytokines with a possible role in implant allergy were measured in patient`s serum (IL-1beta, IL-5, IL-6, IL-8, IL-10, IP-10, IFN γ, TNF α). Group comparison was performed using Mann-Whitney U test for continuous values and chi-square test for categorical values. RESULTS: There were no differences in PROMs between both groups at any follow-up. The majority of patients demonstrated no elevation of the measured blood cytokines. The blood cytokine pattern after 5 years demonstrated no differences between study groups. There was a significant association between elevated IL-8 values and worse results in the overall OKS (p = 0.041), the OKS function component (p = 0.004), the UCLA activity scale (p = 0.007) and the physical component of SF36 (p = 0.001). CONCLUSION: There were no problems with the new coating during mid-term follow-up and no differences in PROMs between coated and standard TKA. Patients with an increased inflammatory response demonstrated worse functional results, regardless of the implant. LEVEL OF EVIDENCE: I. CLINICAL TRIAL REGISTRATION: The study protocol was registered in the US National Institutes of Health's database ( http://www. CLINICALTRIALS: gov ) registry under NCT00862511.

A Novel Multilayer-Coating for Total Knee Arthroplasty Implants is Safe - 10-Year Results From a Randomized-Controlled Trial.

BACKGROUND: This randomized-controlled trial was initiated to compare a new multilayer hypoallergenic coating system with the standard implant in total knee arthroplasty (TKA) in terms of serum metal ion levels, patient-reported outcomes (PROs), and implant survival. METHODS: A total of 120 patients were randomized to receive a coated or standard TKA of the same knee system. Serum metal ion levels (ie, cobalt, chromium, molybdenum, and nickel) as well as knee function (Oxford Knee Score, OKS), quality of life (SF-36), and physical activity (UCLA activity scale) were assessed before surgery and until the 10 year follow-up. A total of 24 patients died and there was one revision in each group. This resulted in 85 patients who completed follow-up. RESULTS: Both groups demonstrated equally good improvement in PROs after surgery and constant score values thereafter. The majority of patients had metal ion serum levels below detection limit. Only cobalt levels demonstrated a slight increase in the standard group at 5- and 10-year follow-up. However, all patients displayed values below 3 µg/L. The cumulative 10-year survival was 98% in both groups. CONCLUSION: There were no problems with the new coating system. No relevant increase in metal ion serum levels were measured. A slight increase in cobalt serum levels in the standard TKA was noted, thus not reaching critical values. The new coating system demonstrated equally good PROs as the standard TKA. Excellent implant survival was observed in both groups. LEVEL OF EVIDENCE: I.

Complications following surgical treatment of posterior malleolar fractures: an analysis of 300 cases.

AIMS: The treatment of ankle fractures and fracture-dislocations involving the posterior malleolus (PM) has undergone considerable changes over the past decade. The aim of our study was to identify risk factors related to the occurrence of complications in surgically treated ankle fractures with PM involvement. PATIENTS AND METHODS: We retrospectively analyzed 300 patients at a mean age of 57 years with 300 ankle fractures involving the PM treated surgically at our institution over a 12-year period. The following relevant comorbidities were noted: arterial hypertension (43.7%; n = 131), diabetes mellitus (DM) (14.0%; n = 42), thereof insulin-dependent (3.7%; n = 11), peripheral vascular disease (0.7%; n = 2), osteoporosis (12.0%; n = 36), dementia (1.0%; n = 3), and rheumatoid arthritis (2.0%; n = 6). Furthermore, nicotine consumption was recorded in 7.3% (n = 22) and alcohol abuse in 4.0% (n = 12). RESULTS: Complications occurred in 41 patients (13.7%). A total of 20 (6.7%) revision surgeries had to be performed. Patients with DM (p < 0.001), peripheral vascular disease (p = 0.003) and arterial hypertension (p = 0.001) had a significantly increased risk of delayed wound healing. Alcohol abuse was associated with a significantly higher overall complication rate (OR 3.40; 95% CI 0.97-11.83; p = 0.043), increased rates of wound healing problems (OR 11.32; 95% CI 1.94-65.60; p = 0.001) and malalignment requiring revision (p = 0.033). The presence of an open fracture was associated with an increased rate of infection and wound necrosis requiring revision (OR 14.25; 95% CI 2.39-84.84; p < 0.001). Multivariate analysis identified BMI (p = 0.028), insulin-dependent DM (p = 0.003), and staged fixation (p = 0.043) as independent risk factors for delayed wound healing. Compared to the traditional lateral approach, using the posterolateral approach for fibular fixation did not lead to increased complication rates. CONCLUSIONS: Significant risk factors for the occurrence of complications following PM fracture treatment were identified. An individually tailored treatment regimen that incorporates all risk factors is important for a good outcome.

Ultracongruent insert design is a safe alternative to posterior cruciate-substituting total knee arthroplasty: 5-year results of a randomized controlled trial.

PURPOSE: If substitution of the posterior cruciate ligament in total knee arthroplasty is necessary, there are two options available: posterior stabilized (PS) design with a post-cam mechanism or anterior-lipped ultracongruent (UC) inserts. UC inserts have the advantage that no femoral box is necessary and a standard femoral component can be used. The aim of this study was to compare the range of motion (ROM) and patient-reported outcome (PRO) after UC and PS fixed-bearing TKA. Better ROM in PS TKA and no difference in PRO between both designs was hypothesized. METHODS: A randomized controlled trial with 127 patients receiving a fixed-bearing UC or PS design of the same knee system was performed. Nine patients died and there were four revision surgeries. 107 patients completed the 5-year follow-up. Patient-reported outcome was assessed. Patellofemoral problems were evaluated using selected applicable questions of the Oxford Knee Score (getting up from a table, kneeling, climbing stairs). RESULTS: Surgical time was 10 min shorter in the UC group (p < 0.001). After 5 years, both groups demonstrated good knee function and health-related quality of life without significant differences between the groups. Both groups demonstrated a high satisfaction score and the majority of patients would undergo this surgery again. Patellofemoral problems were recognized more frequently in the PS group (p = 0.025). CONCLUSION: Both designs demonstrated similar good results after 5 years. Stabilization with an anterior-lipped UC insert can be considered a safe alternative to the well-established PS design if cruciate substitution is necessary.

Symptom Burden and Palliative Care Needs of Patients with Incurable Cancer at Diagnosis and During the Disease Course.

BACKGROUND: Although current guidelines advocate early integration of palliative care, symptom burden and palliative care needs of patients at diagnosis of incurable cancer and along the disease trajectory are understudied. MATERIAL AND METHODS: We assessed distress, symptom burden, quality of life, and supportive care needs in patients with newly diagnosed incurable cancer in a prospective longitudinal observational multicenter study. Patients were evaluated using validated self-report measures (National Comprehensive Cancer Network Distress Thermometer [DT], Functional Assessment of Cancer Therapy [FACT], Schedule for the Evaluation of Individual Quality of Life [SEIQoL-Q], Patients Health Questionnaire-4 [PHQ-4], modified Supportive Care Needs Survey [SCNS-SF-34]) at baseline (T0) and at 3 (T1), 6 (T2), and 12 months (T3) follow-up. RESULTS: From October 2014 to October 2016, 500 patients (219 women, 281 men; mean age 64.2 years) were recruited at 20 study sites in Germany following diagnosis of incurable metastatic, locally advanced, or recurrent lung (217), gastrointestinal (156), head and neck (55), gynecological (57), and skin (15) cancer. Patients reported significant distress (DT score ≥ 5) after diagnosis, which significantly decreased over time (T0: 67.2%, T1: 51.7%, T2: 47.9%, T3: 48.7%). The spectrum of reported symptoms was broad, with considerable variety between and within the cancer groups. Anxiety and depressiveness were most prevalent early in the disease course (T0: 30.8%, T1: 20.1%, T2: 14.7%, T3: 16.9%). The number of patients reporting unmet supportive care needs decreased over time (T0: 71.8 %, T1: 61.6%, T2: 58.1%, T3: 55.3%). CONCLUSION: Our study confirms a variable and mostly high symptom burden at the time of diagnosis of incurable cancer, suggesting early screening by using standardized tools and underlining the usefulness of early palliative care. IMPLICATIONS FOR PRACTICE: A better understanding of symptom burden and palliative care needs of patients with newly diagnosed incurable cancer may guide clinical practice and help to improve the quality of palliative care services. The results of this study provide important information for establishing palliative care programs and related guidelines. Distress, symptom burden, and the need for support vary and are often high at the time of diagnosis. These findings underscore the need for implementation of symptom screening as well as early palliative care services, starting at the time of diagnosis of incurable cancer and tailored according to patients' needs.

Similar outcomes in computer-assisted and conventional total knee arthroplasty: ten-year results of a prospective randomized study.

BACKGROUND: Computer-assisted navigation (CAS) was developed to improve the surgical accuracy and precision. Many studies demonstrated better alignment in the coronal plane in CAS TKA compared to conventional technique. The influence on the functional outcome is still unclear. Only few studies report long-term results of CAS TKA. This study was initiated to investigate 10-year patient-reported outcome of CAS and conventional TKA. METHODS: From initially 80 patients of a randomized study of CAS and conventional TKA a total of 50 patients could be evaluated at the 10-year follow-up. The Knee Society Score and EuroQuol Questionnaire were assessed. For all patients a competing risk analysis for revision was performed. RESULTS: The patient-reported outcome measures demonstrated similar values for both groups. The 10-year risk for revision was 2.5% for conventional TKA and 7.5% for CAS TKA (p=0.237). CONCLUSIONS: There was no difference between CAS and conventional TKA with regard to patient-reported outcome and revision risk ten years after surgery. TRIAL REGISTRATION: This study was registered at clinicaltrials.gov on 11/30/2009, ID: NCT01022099 .

Better short-term function after unicompartmental compared to total knee arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an established treatment option for patients with unicompartmental osteoarthritis (OA). However, strict patient selection is crucial for its success. The proposed advantages include nearly natural knee kinematics, faster rehabilitation and better functional outcomes. Despite the aforementioned facts and it's proven cost-effectiveness, there are still hesitations for the use of UKA as an alternative to total knee arthroplasty (TKA). Key objectives of this study were therefore to assess clinical and patient-reported outcome (PRO) as well as patient's satisfaction after medial UKA in comparison to TKA. METHODS: To assess the outcome after UKA we conducted a prospective multi-center study. 116 patients with unicompartmental OA and indication for UKA were included. Overall 54 females and 62 males with an average age of 62.7 years (±9.8) and an average body mass index (BMI) of 29.2 (± 3.7) were recruited. Clinical results and PRO were assessed using the Knee Society Score (KSS). Follow-ups took place 3 months, 1 and 2 years after surgery including clinical examination, radiographs, assessment of PRO and adverse events. Pain and satisfaction was evaluated using a visual analog scale (VAS, 0 (worst) to 10 (best)). For comparison with TKA a propensity score matched-pair analysis was performed to eliminate confounders. Matching criteria were gender, patient's age, BMI and comorbidities. A total of 116 matched-pairs were analysed. RESULTS: There was no revision in the UKA group until 2 years after surgery. Revision rates were higher in the TKA group (0.6%). Preoperative KSS-Scores were higher within the UKA cohort (p <  0.001). After surgical treatment, PROMs displayed a significant improvement (p <  0,001) in both cohorts. Regarding the Knee-Score (Pain, Alignment, ROM) we observed no differences between cohorts after 12 months. The Function-Score demonstrated significantly better results in the UKA cohort (UKA vs. TKA 95 vs 80, p <  0.001). Patient satisfaction was also higher in UKA patients (UKA vs TKA 9.0 vs 8.8, p = 0.019). CONCLUSION: Patients of both cohorts showed high satisfaction after knee arthroplasty. UKA resulted in higher function scores compared to TKA without increased revision rate during short-term follow-up. Therefore, UKA is a good treatment option for unicompartmental OA. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04598568 . Registered 22 October 2020 - Retrospectively registered.

An individualized decision aid for physicians and patients for total knee replacement in osteoarthritis (Value-based TKR study): study protocol for a multi-center, stepped wedge, cluster randomized controlled trial.

BACKGROUND: Total knee replacement (TKR) is one of the most commonly performed routine procedures in the world. Prognostic studies indicate that the number of TKR will further increase constituting growing burden on healthcare systems. There is also substantial regional heterogeneity in TKR rates within and between countries. Despite the known therapeutic effects, a subset of patients undergoing TKR does not benefit from the procedure as intended. To improve the appropriateness of TKR indication, the EKIT initiative ("evidence and consensus based indication critera for total arthroplasty") developed a clinical guideline for Germany on the indication of TKR. This guideline is the basis for a digital medical decision aid (EKIT tool) to facilitate shared decision making (SDM) in order to improve decision quality for elective surgery. The aim of this cluster randomized trial is to investigate the effectiveness of the EKIT tool on decision quality. METHODS: The Value-based TKR study is a prospective pragmatic multi-center, stepped wedge, cluster randomized controlled trial (SW-RCT). The EKIT tool provides (1) a systematic presentation of individual patient and disease-specific information (symptoms, expectations), (2) the fulfillment of the indication criteria and (3) health information about safety and effectiveness of TKR. All study sites will follow routine care as control clusters until the start of the intervention. In total, there will be 10 clusters (study sites) and 6 sequential steps over 16 month, with clusters receiving the intervention with a minimum 2 months of standard routine care. The primary outcome is patients' decision quality measured with the Decision Quality Instrument (DQI)-Knee Osteoarthritis questionnaire. Furthermore, we will collect information on global patient satisfaction, patient reported outcome measures and the fulfilment of the individual expectations 12 months after SDM. The power calculation yielded an estimated power of 89% using robust Poisson regression under the following assumptions: 10 study sites with a total of N=1,080 patients (including a dropout rate of 11%), a 10% increase in decision quality due to the use of the EKIT tool, and a significance level of 5%. DISCUSSION: There is a high potential for transferring the intervention into routine practice if the evaluation is positive. TRIAL REGISTRATION: ClinicalTrials.gov: NCT04837053 . Registered on 08/04/2021.

Higher treatment effect after total knee arthroplasty is associated with higher patient satisfaction.

PURPOSE: The aim of this study was to investigate what influence the treatment effect after total knee arthroplasty (TKA) had on patient satisfaction. METHODS: Prospective registry data of a University-based arthroplasty centre were used. 582 patients with unilateral bicondylar TKA were analyzed. Treatment effect (TE) was deduced from Oxford Knee Score (OKS) before and one year after surgery. Positive values correspond to improved symptoms (maximum 1.0 reflect no symptoms at all) and negative values correspond to deterioration of symptoms. Satisfaction on a visual-analogue scale from 0 to 10 and the willingness to undergo TKA surgery again was assessed one year after surgery. RESULTS: The mean OKS improved from 22.1 before to 36.7 one year after TKA. Treatment effects ranged from 1.0 to -0.62 with a mean TE of 0.56. Taking an individual treatment effect of 0.2 as a cut-off between responder and non-responder, a total of 85.8% would be classified as responder after TKA. The mean satisfaction score with the TKA was 8.1. There was a significant correlation between the individual treatment effect and satisfaction after TKA (p < 0.001). The majority of patients (84.5%) would undergo surgery again. Patients not willing to undergo surgery again or those uncertain about this had lower satisfaction scores, a lower treatment effect and were more often female compared to patients who would undergo surgery again. CONCLUSION: Higher individual treatment effects resulted in higher patient satisfaction and willingness to undergo surgery again. However, some patients with a relatively low treatment effect were highly satisfied, which indicates the need for both information. LEVEL OF EVIDENCE: II.

[Are the results of total knee arthroplasty after high tibial osteotomy worse?] / Sind die Ergebnisse von Knietotalendoprothesen nach Tibiakopfumstellungsosteotomie schlechter?

BACKGROUND: In some cases, total knee arthroplasty (TKA) following high tibial osteotomy (HTO) is necessary. HTO can adversely affect anatomy and alignment resulting in more complicated and challenging TKA surgery. The aim of this study was to investigate whether patients having undergone HTO benefit from TKA to the same extent as patients with primary osteoarthritis of the knee. METHODS: A total of 44 patients after HTO and 1703 patients with primary osteoarthritis of the knee were identified in the local registry. To reduce confounders, a 1:1 propensity score matched-pair analysis (age, gender, BMI, comorbidities) was carried out in patients with a 5-year follow-up. This resulted in 35 matched pairs, which were compared for knee function, pain level, satisfaction and perioperative data (operative time, implant type, complications) and revisions. RESULTS: Patients having undergone HTO had no significant differences in knee function prior and 5 years after surgery but a significantly higher pain level. Despite the higher pain level before and after TKA, there was a similar satisfaction with the result of the surgery. The operative time for TKA was significantly longer after HTO and modular implants with stem and wedges were used significantly more often. The two cohorts did not differ with respect to complications within the first 3 months after surgery. The revision rate within 5 years was not increased in patients after HTO. CONCLUSION: Patients having undergone HTO achieved a similar knee function in comparison to patients with primary osteoarthritis of the knee after TKA. However, a higher pre- and postoperative pain level was recorded in patients following HTO. The surgical effort was significantly higher after HTO.

Slightly better pain relief but more frequently motor blockade with combined nerve block analgesia compared to continuous intraarticular analgesia after total knee arthroplasty.

PURPOSE: Pain management after total knee arthroplasty (TKA) is still under debate. Continuous peripheral nerve blocks (PNB) can provide long pain relief but impair muscle function. Continuous intraarticular analgesia could result in longer pain relief than local infiltration analgesia without negative effects on muscle function. This study investigated the efficacy of pain control between PNB's and continuous intraarticular analgesia after TKA. METHODS: A prospective randomized study on 140 patients undergoing TKA was performed. Patients received either a combination of continuous femoral nerve block, continuous sciatic nerve block and single-shot obturator nerve block (group R) or a local infiltration analgesia and a continuous intraarticular catheter with ropivacaine (group L). Primary outcome was pain measured on a numerical rating scale. Knee function, patient-reported outcome (PRO) and adverse events were assessed until 1 year after surgery. RESULTS: Pain at rest was lower in group R on the day of surgery (mean NRS 3.0 vs. 4.2) and the morning of postoperative day 1 (mean NRS 3.4 vs. 4.4). Motor blockade longer than postoperative day 3 occurred more often in group R compared to group L (15.3% vs. 1.5%). Pain levels, PRO and satisfaction 3-month and 1-year after surgery were similar. CONCLUSION: Continuous PNB's were slightly more effective in the first 24 h after surgery but were associated more often with motor blockade which should be avoided. It must be balanced if the small amount of better pain relief immediately after surgery justifies the risks associated with motor blockade following PNB's. LEVEL OF EVIDENCE: I.

Intraarticular use of tranexamic acid reduces blood loss and transfusion rate after primary total knee arthroplasty.

BACKGROUND: Tranexamic acid (TXA) is effective in reduction of hemorrhage after major surgical procedures. In total joint replacement it is commonly administered intravenously. Despite various studies regarding the safety of its antifibrinolytic effect there are contraindications for systemic use. In total knee arthroplasty (TKA) TXA can also be administered intraarticular. However, there is a lack of studies focusing on dosage, effectiveness and complications of this local treatment. This study aimed to evaluate if blood loss and transfusion rate can be reduced in primary TKA by local application of TXA. METHODS: We included a total of 202 consecutive primary, unilateral TKA patients, 101 without and 101 with intraartricular application of 2 g TXA. Surgery was conducted after a standardized protocol. Blood loss, transfusion and complication rates were evaluated until three months after surgery. Blood loss was estimated using the hematocrit-value (Hk) prior and five days after surgery by Rosenecher's and Mercuriali's formula. RESULTS: By the use of TXA a significant reduction of blood loss (Rosencher average 1220 ml vs 1900 ml, Mercuriali average 430 ml vs 700 ml p < 0,001) and transfusion rate (0% vs 24.75% of patients, p < 0,001) was observed. There were no differences regarding complication rates. Due to the lower cost of TXA compared to applied erythrocyte concentrates a side effect of the treatment was a cost reduction of € 1.609 within this cohort. CONCLUSIONS: The intraarticular application of 2 g TXA resulted in a significant reduction of blood loss and transfusion rate after primary TKA without increased complication rates. This method therefore seems to be a safe and cost effective instrument to reduce perioperative blood loss. However, it has to be considered that this is an off-label use.

Fulfillment of expectations influence patient satisfaction 5 years after total knee arthroplasty.

PURPOSE: Constant efforts have been made to improve prosthesis design in total knee arthroplasty (TKA), but a significant number of patients remain dissatisfied postoperatively. Besides poor improvement in pain or function, poor fulfillment of patients expectations were identified as contributing factors. Purpose of the study was to assess fulfillment of patients' expectations and satisfaction with TKA 5 years after surgery. METHODS: A total of 103 patients from a prospective randomised study of a high-flexion or standard TKA implant were investigated 5 years after surgery and patient-reported outcomes (PRO), fulfillment of expectations and satisfaction with the result of the surgery were obtained. RESULTS: There were no differences in PROs, fulfillment of expectations and satisfaction between both implant designs. In total, the patients had high expectations preoperatively, mainly related to pain relief and functional abilities. A total of 89.4% of these expectations were fulfilled. No re-interventions (p < 0.001) and male gender (p = 0.017) were the most important predictors of higher fulfillment of expectations. Satisfaction scored highly at 8.2 out of 10 and most patients (93.2%) would undergo the surgery again. Higher Knee Score (p = 0.012) and fulfillment of expectations (p = 0.002) were correlated with higher satisfaction. CONCLUSION: Five years after surgery fulfillment of expectations and satisfaction were high regardless of implant design and did significantly influence patient satisfaction. Surgeons should be aware of the importance of patients' expectations and their influence on satisfaction after TKA. Therefore, the probability of fulfillment should be discussed during shared decision making for TKA. LEVEL OF EVIDENCE: I.

Analysis of Total Knee Arthroplasty revision causes.

BACKGROUND: The number of revision Total Knee Arthroplasty (TKA) is rising in many countries. The aim of this study was the prospective assessment of the underlying causes leading to revision TKA in a tertiary care hospital and the comparison of those reasons with previously published data. METHODS: In this study patients who had revision TKA between 2010 and 2015 were prospectively included. Revision causes were categorized using all available information from patients' records including preoperative diagnostics, intraoperative findings as well as the results of the periprosthetic tissue analysis. According to previous studies patients were divided into early (up to 2 years) and late revision (more than 2 years). Additional also re-revisions after already performed revision TKA were included. RESULTS: We assessed 312 patients who underwent 402 revision TKA, 89.6% of them were referred to our center for revision surgery. In 289 patients (71.9%) this was the first revision surgery after primary TKA. Among the first revisions the majority was late revisions (73.7%). One hundred thirteen patients (28.1%) had already had one or more revision surgeries before. Overall, the most frequent reason for revision was infection (36.1%) followed by aseptic loosening (21.9%) and periprosthetic fracture (13.7%). CONCLUSIONS: In a specialized arthroplasty center periprosthetic joint infection (PJI) was the most common reason for revision and re-revision TKA. This is in contrast to population-based registry data and has consequences on costs as well as on success rates in such centers.