Einfluss des tibialen Slopes auf die sagittale Kniegelenksstabilität

Hintergrund: Der Stellenwert der dorsalen Reklination des Tibiaplateaus (tibialer Slope) hat in den letzten Jahren in der gelenkerhaltenden Kniegelenkschirurgie zugenommen. Methodik: In der vorliegenden Habilitationsschrift wurde der Einfluss des tibialen Slopes auf die sagittale Kniegelenksstabilität untersucht Ergebnisse: Es konnte gezeigt werden, dass der tibiale Slope ganz unterschiedliche Werte betragen kann, aber auch eine exzessive Ausprägung nicht zwingend einen Krankheitswert hat (Arbeit 2). Trotzdem spielt diese Ausprägung bei fast jeder Operation des Kniegelenkes eine Rolle, so dass der tibiale Slope im klinischen Alltag gemessen (Arbeit 1), in den Entscheidungsprozess einer operativen Indikationsstellung einbezogen (Arbeit 3, 4, 5, 6) und bei einem Therapieversagen korrigiert werden sollte (Arbeit 7). Zusammenfassung: Es konnte gezeigt werden, dass der tibiale Slope einen großen Einfluss sowohl auf die vordere als auch auf die hintere Kniegelenksstabilität hat. Dieses Wissen kann somit bereits im Vorfeld einer operativen Versorgung zur Identifikation von Risikopatienten für ein späteres Therapieversagen beitragen

Recommendations for Patients with High Return to Sports Expectations after TKA Remain Controversial

(1) Background: Improved surgical techniques and implants in total knee arthroplasty (TKA) have led to broader indications for surgical interventions of osteoarthritis of the knee. There is a growing young and active patient subgroup with high return to sports (RTS) expectations after TKA. The current lack of evidence regarding RTS capacity in this patient cohort, requires the consolidation of experts' opinions and experiences to address the special needs among these patients. The aim of this study was to assess current expert opinions in regard to preoperative patient assessment, surgical technique and decision-making and patient counseling for these patients. (2) Methods: We performed a survey among surgeons specialized in arthroplasty with a questionnaire designed to assess current recommendations, surgical techniques, and implant preferences as well as patient counseling in patients with high expectations for RTS after TKA. (3) Results: The majority of surgeons are in favor of return to low-impact sports after TKA within 3 to 6 months. Some even recommend return to high-impact sports. Despite improvement of surgical techniques and implants, we observed no clear preference for a single surgical technique or implant specification in active patients. (4) Conclusions: Current evidence for sports-associated complications after TKA is scarce. Despite a growing array of surgical techniques and implants, the available literature is still controversial with no single surgical technique or TKA design distinguishing itself clearly from others. Surgeons' recommendations are mostly based on their experience and training. Nonetheless, we observed growing faith in modern implants with some surgeons even recommending high-impact sports after TKA

The subjective knee value is a valid single-item survey to assess knee function in common knee disorders

Introduction: The patient's perspective plays a key role in judging the effect of knee disorders on physical function. We have introduced the Subjective Knee Value (SKV) to simplify the evaluation of individual's knee function by providing one simple question. The purpose of this prospective study was to validate the SKV with accepted multiple-item knee surveys across patients with orthopaedic knee disorders. Materials and methods: Between January through March 2020, consecutive patients (n = 160; mean age 51 +/- 18 years, range from 18 to 85 years, 54% women) attending the outpatient clinic for knee complaints caused by osteoarthritis (n = 69), meniscal lesion (n = 45), tear of the anterior cruciate ligament (n = 23) and focal chondral defect (n = 23) were invited to complete a knee-specific survey including the SKV along with the Knee Injury Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee subjective knee form (IKDC-S). The Pearson correlation coefficient was used to evaluate external validity between the SKV and each patient-reported outcome measure (PROM) separately. Furthermore, patient's compliance was assessed by comparing responding rates. Results: Overall, the SKV highly correlated with both the KOOS (R = 0.758, p < 0.05) and the IKDC-S (R = 0.802, p < 0.05). This was also demonstrated across all investigated diagnosis- and demographic-specific (gender, age) subgroups (range 0.509-0.936). No relevant floor/ceiling effects were noticed. The responding rate for the SKV (96%) was significantly higher when compared with those for the KOOS (81%) and the IKDC-S (83%) (p < 0.05). Conclusion: At baseline, the SKV exhibits acceptable validity across all investigated knee-specific PROMs in a broad patient population with a wide array of knee disorders. The simplified survey format without compromising the precision to evaluate individual's knee function justifies implementation in daily clinical practice. Level of evidence II, cohort study (diagnosis)

Metal on Metal Bearing in Total Hip Arthroplasty and its Impact on Synovial Cell Count

Introduction: The effect of different bearings on synovial white blood cell (WBC) count and polymorphonuclear percentage (PMN%) in aspirations remains unclear. Therefore, this study investigates the impact of aseptic Metal-on-Metal (MoM) bearing on synovial fluid. Methods: We searched our arthroplasty registry for aseptic painful THAs with MoM bearings between 2011 and 2018. Then, a case-matched control group was selected with septic and aseptic Total Hip Arthroplasty (THA) with ceramic on a polyethylene (PE) bearing. The matching criteria consisted of gender, age +/-10 years, and time of aspiration (+/-2years). Periprosthetic Joint Infection (PJI) was defined according to the Infectious Diseases Society of America (IDSA), and Musculoskeletal Infection Society (MSIS) using bacterial cultures, sonication and histology. Results: In total, 19 patients who underwent hip aspiration with MoM bearing were identified. Five patients had to be excluded due to insufficient synovial fluid obtained (n = 2) or bacterial growth after sonication that was initially negative with the standard microbiological cultures (n = 3). As such, 14 were included. These patients were matched with 14 aseptic and 14 septic THAs with ceramic on a PE bearing, which constituted the control group. The mean serum chrome level was 20.0 ± 15.5 nmol/L and cobalt level 18.4 ± 22.1 nmol/L. The synovial WBC and PMN% varied significantly between MoM bearing group and the aseptic THA ceramic PE group (both p < 0.001), as well as the septic THA group (WBC p = 0.016, PMN% p < 0.001). Furthermore, the septic THA group had significantly higher CRP values than the aseptic MoM group (p = 0.016). Conclusion: MoM bearing shows significantly higher synovial WBC and PMN% when compared to aseptic THA with ceramic on PE bearing above the MSIS cut-off. This is an important consideration when diagnosing periprosthetic joint infection using the MSIS guidelines

Reaction time and brake pedal force after total knee replacement: timeframe for return to car driving

Purpose: This prospective cohort study aimed to examine objective and subjective parameters in patients who underwent total knee replacement (TKR) to assess from when on driving a car can be deemed safe again. Methods: Thirty patients (16 women, 14 men, age 66±11 years) who received TKR of the right knee and 45 healthy controls (26 women, 19 men, age 32±9 years) were asked to perform an emergency braking manoeuvre using a driving simulator. Brake pedal force (BPF), neuronal reaction time (NRT), brake reaction time (BRT), and subjective parameters (pain, subjective driving ability) were measured preoperatively as well as 5 days, 3–4, and 6 weeks after TKR. Results: Preoperative NRT was 506±162 ms, BRT 985±356 ms, and BPF 614±292 N. NRT increased to 561±218 ms, BRT to 1091±404 ms and BPF decreased to 411±191 N 5 days after TKR. Three weeks after surgery, NRT was 581±164 ms and BRT 1013±260 ms, while BPF increased to 555±200 N. Only BPF showed signifcant diferences (p<0.01). In week 6, all parameters were restored to baseline levels; patients showed signifcant pain decrease and evaluated their driving abil ity as “good” again. Conclusion: BPF was the only parameter displaying a signifcant postoperative decrease. However, preoperative patients’ baseline levels and subjective confdence in driving ability were only reached 6 weeks after the operation. These results indicate that a minimum waiting period of 6 weeks should be considered before patients can safely participate in road traffic at their individual preoperative safety level again. Level of evidence II

Significant increase in quantity and quality of knee arthroplasty related research in KSSTA over the past 15 years

Purpose: This study aimed to evaluate both publication and authorship characteristics in Knee Surgery, Sports Traumatology, Arthroscopy journal (KSSTA) regarding knee arthroplasty over the past 15 years. Methods: PubMed was searched for articles published in KSSTA between January 1, 2006, and December 31st, 2020, utilising the search term 'knee arthroplasty'. 1288 articles met the inclusion criteria. The articles were evaluated using the following criteria: type of article, type of study, main topic and special topic, use of patient-reported outcome scores, number of references and citations, level of evidence (LOE), number of authors, gender of the first author and continent of origin. Three time intervals were compared: 2006-2010, 2011-2015 and 2016-2020. Results: Between 2016 and 2020, publications peaked at 670 articles (52%) compared with 465 (36%) published between 2011 and 2016 and 153 articles (12%) between 2006 and 2010. While percentage of reviews (2006-2010: 0% vs. 2011-2015: 5% vs. 2016-2020: 5%) and meta-analyses (1% vs. 6% vs. 5%) increased, fewer case reports were published (13% vs. 3% vs. 1%) (p < 0.001). Interest in navigation and computer-assisted surgery decreased, whereas interest in perioperative management, robotic and individualized surgery increased over time (p < 0.001). There was an increasing number of references [26 (2-73) vs. 30 (2-158) vs. 31 (1-143), p < 0.001] while number of citations decreased [30 (0-188) vs. 22 (0-264) vs. 6 (0-106), p < 0.001]. LOE showed no significant changes (p = 0.439). The number of authors increased between each time interval (p < 0.001), while the percentage of female authors was comparable between first and last interval (p = 0.252). Europe published significantly fewer articles over time (56% vs. 47% vs. 52%), whereas the number of articles from Asia increased (35% vs. 45% vs. 37%, p = 0.005). Conclusion: Increasing interest in the field of knee arthroplasty-related surgery arose within the last 15 years in KSSTA. The investigated topics showed a significant trend towards the latest techniques at each time interval. With rising number of authors, the part of female first authors also increased-but not significantly. Furthermore, publishing characteristics showed an increasing number of publications from Asia and a slightly decreasing number in Europe

CKD-MBD after kidney transplantation

Successful kidney transplantation corrects many of the metabolic abnormalities associated with chronic kidney disease (CKD); however, skeletal and cardiovascular morbidity remain prevalent in pediatric kidney transplant recipients and current recommendations from the Kidney Disease Improving Global Outcomes (KDIGO) working group suggest that bone disease—including turnover, mineralization, volume, linear growth, and strength—as well as cardiovascular disease be evaluated in all patients with CKD. Although few studies have examined bone histology after renal transplantation, current data suggest that bone turnover and mineralization are altered in the majority of patients and that biochemical parameters are poor predictors of bone histology in this population. Dual energy X-ray absorptiometry (DXA) scanning, although widely performed, has significant limitations in the pediatric transplant population and values have not been shown to correlate with fracture risk; thus, DXA is not recommended as a tool for the assessment of bone density. Newer imaging techniques, including computed tomography (quantitative CT (QCT), peripheral QCT (pQCT), high resolution pQCT (HR-pQCT) and magnetic resonance imaging (MRI)), which provide volumetric assessments of bone density and are able to discriminate bone microarchitecture, show promise in the assessment of bone strength; however, future studies are needed to define the value of these techniques in the diagnosis and treatment of renal osteodystrophy in pediatric renal transplant recipients

Recommendations for return to sports after total hip arthroplasty are becoming less restrictive as implants improve

Introduction: Total hip arthroplasty (THA) surgeries are expected to exponentially increase in the upcoming years, likely because of the overall broader indication of THAs. With these developments, an increasing number of younger (< 50 years) and active patients will receive surgical interventions, and expectations for an active lifestyle will accordingly increase. In addition, surgeons now have a growing array of techniques and implant materials to choose from. Despite these developments, evidence to provide the best standard-of-care to patients with high expectations for return to sports (RTS) is scarce and urgently needed. What recommendations do arthroplasty surgeons currently make to patients with high return to sports expectations, what factors may influence their recommendations and what surgical techniques and implant specifications are considered favorable in the treatment of patients with a more active lifestyle? This study was conducted to analyze the current recommendations, patient assessment, and patient counseling after THA to identify trends and relevant factors for surgical decision-making in patients with high-RTS expectations. Material and methods: We designed a questionnaire comprising five general items and 19 specific items that included 46 sub-items for hip arthroplasty and conducted a survey among 300 German surgeons specialized in arthroplasty at the German Arthroplasty Society (AE) to assess expert opinions, recommendations, surgical decision-making, and patient counseling for patients with high expectations for RTS after THA. Results: The majority of surgeons (81.9%) were in favor of RTS after THA. Risks associated with sports after THA were considered minimal (1%), with periprosthetic fractures ranking highest, followed by hip dislocation and polyethylene wear. Some surgical decision-making was influenced by high-RTS expectations in regard to implant fixation, stem type, femoral head diameter, and bearing-surface tribology. We observed an increasingly liberal counseling of patients for high-impact sports. Conclusion: With the improvement of implants and surgical techniques, surgeons are more willing to encourage patients to adopt a more active lifestyle. However, the true long-term limitations need further investigation in future studies. Level of evidence: 5 Expert opinions

Serum and Synovial Markers in Patients with Rheumatoid Arthritis and Periprosthetic Joint Infection

Current diagnostic standards for PJI rely on inflammatory markers that are typically elevated in autoimmune diseases, thus making the diagnosis of PJI in patients with rheumatoid arthritis and joint replacement particularly complicated. There is a paucity of data on differentiating PJI from rheumatoid arthritis in patients with previous arthroplasty. In this study, we retrospectively analyzed the cases of 17 patients with rheumatoid arthritis and 121 patients without rheumatoid disease who underwent surgical intervention due to microbiology-positive PJI of the hip or knee joint. We assessed clinical patient characteristics, laboratory parameters, and prosthesis survival rates in patients with and without rheumatoid arthritis and acute or chronic PJI. ROC analysis was conducted for the analyzed parameters. In patients with chronic PJI, peripheral blood CRP (p = 0.05, AUC = 0.71), synovial WBC count (p = 0.02, AUC = 0.78), synovial monocyte cell count (p = 0.04, AUC = 0.75), and synovial PMN cell count (p = 0.02, AUC = 0.80) were significantly elevated in patients with rheumatoid arthritis showing acceptable to excellent discrimination. All analyzed parameters showed no significant differences and poor discrimination for patients with acute PJI. Median prosthesis survival time was significantly shorter in patients with rheumatoid arthritis (p = 0.05). In conclusion, routinely used laboratory markers have limited utility in distinguishing acute PJI in rheumatoid patients. In cases with suspected chronic PJI but low levels of serum CRP and synovial cell markers, physicians should consider the possibility of activated autoimmune arthritis

Major Shortening of the Patellar Tendon During Septic Two-Stage Knee Arthroplasty Revision Using Static Spacers

Background: Two-stage septic revision knee arthroplasty (TKA) often results in inferior functional outcome after reimplantation, which might be due to impairments of the extensor mechanism. The aim of the current study was to elucidate possible alterations in extensor mechanisms during septic two -stage revision of TKA treated with a static spacer.Methods: This retrospective study included 87 patients (42 women, 45 men, age 64.5 +/- 10.5; range, 29-85 years) undergoing septic two-stage TKA revision using a static spacer. The modified Insall Salvati ratio (mISR) was calculated via calibrated true lateral radiographs by two independent orthopedic surgeons before TKA explantation (G0), 6-8 days after TKA removal (G1), one day before TKA reimplantation (G2) and 6-8 days after TKA reimplantation (G3). Age, sex, body mass index (BMI), index C-reactive protein level, and number of previous surgeries were evaluated to identify the possible correlations.Results: Overall, mISR significantly decreased within the first 6 days after index surgery from 1.71 +/- 0.41 to 1.63 +/- 0.41 (G0 versus G1, P = 10% experienced patellar tendon shortening of 16% between G0 and G1, 19% between G0 and G2 and up to 20% between G0 and G3. There were weak correlations concerning age (r =-0.240, P = .038), preoperative C-reactive protein level (r = 0.239, P = .04) and patellar tendon shortening. Intraclass correlation coefficient (ICC)was 0.88 concerning radiographic measurement.Conclusion: Septic two-stage TKA revision using static spacers leads to irreversible alterations of the extensor mechanism, specifically a major shortening of the patellar tendon, in one out of 3 patients. Level of evidence: II.(c) 2022 Elsevier Inc. All rights reserved