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Background Aseptic loosening is one of the most common reasons for revision in knee arthroplasty. Its pathogenesis is multifactorial, and early diagnosis is necessary to initiate appropriate therapy and to avoid serious complications, such as substantial bone loss or even periprosthetic fractures. Objectives This paper describes the current standard in the diagnosis of aseptic loosening in total knee arthroplasty. Sensitivity and specificity of the individual diagnostic procedures are presented, and other causes for differential diagnoses of painful total knee arthroplasty (TKA) are discussed. Results In the case of suspected loosening in TKA, infection diagnostics should be performed to rule out periprosthetic infection, as this is crucial in terms of surgical strategy. The gold standard in diagnosing aseptic loosening is conventional radiography. Radiolucent lines at the cement-bone or metal-cement interface of more than 2 mm or increasing in translucency, migration of components, and cement fractures are obvious signs of loosening. Artifact-reduced computed tomography can bring additional information regarding periprosthetic osteolysis. A single bone scan is not reliable in diagnosing aseptic loosening, especially in the first 2 years after surgery. Single photon emission computed tomography (SPECT-CT) could be a useful extension in loosening diagnosis in the future. Conclusions The diagnosis of aseptic loosening poses a great challenge to the treating physician and requires a structured diagnostic algorithm. After exclusion of infection, conventional radiography is the basic examination, which should be supplemented by computed tomography and nuclear medicine examinations according to the clinical symptoms and the time course.

Aufgrund einer Unterschatzung des femoralen Knochenverlusts kommt es in der Revisionsknieendoprothetik haufig zu einer Proximalisierung der Gelenklinie. Die korrekte Rekonstruktion der Gelenklinie hat jedoch im Revisionsfall wie auch bei der Primarimplantation einen entscheidenden Einfluss auf die Funktion und das klinische Ergebnis. Zusatzlich spielt der Patellastand eine entscheidende Rolle fur die Kinematik im Patellofemoralgelenk und fur die resultierende Funktion nach Wechseloperation. Von den in der Literatur zur Orientierung und Bestimmung der physiologischen Gelenklinie beschriebenen anatomischen Landmarken, die sowohl zur praoperativen Planung als auch intraoperativ herangezogen werden konnen, sind die Epikondylen- und die Adduktor-Ratio am zuverlassigsten. Gleichzeitig zeigen die tibial referenzierten Messungen eine hohe Varianz und eignen sich nicht als alleinige Referenzierung. Ein bestehender femoraler Knochenverlust sollte durch den groszugigen Einsatz von Femuraugmenten ausgeglichen werden. Durch eine korrekte Rekonstruktion der Gelenklinie lassen sich auch in der Revisionsendoprothetik signifikant bessere Ergebnisse erzielen.

Das Ziel der Implantation einer medialen Schlittenprothese mit fixer Plattform ist die anatomische Rekonstruktion des medialen Gelenkkompartimentes. Nach Festlegung der korrekten Rotation, Hohe und medialen Inklination wird die arthrotische tibiale Gelenkflache reseziert. Anschliesend erfolgt die Praparation des medialen Femurkondylus uber den Spacer- und 3‑in-1-Block. Nach der Meniskektomie wird die tibiale Praparation abgeschlossen und nach Abtragen dorsaler femoraler Osteophyten das Ergebnis der bisherigen Schritte mit den einliegenden Probekomponenten uberpruft. Nun werden die Probeteile entfernt, eine lokale Infiltrationsanasthesie appliziert, das Knochenbett gereinigt sowie getrocknet und anschliesend die Prothesenkomponenten implantiert.

Aseptic loosening is one of the most common reasons for revision in knee arthroplasty. Its pathogenesis is multifactorial, and early diagnosis is necessary to initiate appropriate therapy and to avoid serious complications, such as substantial bone loss or even periprosthetic fractures.This paper describes the current standard in the diagnosis of aseptic loosening in total knee arthroplasty. Sensitivity and specificity of the individual diagnostic procedures are presented, and other causes for differential diagnoses of painful total knee arthroplasty (TKA) are discussed.In the case of suspected loosening in TKA, infection diagnostics should be performed to rule out periprosthetic infection, as this is crucial in terms of surgical strategy. The gold standard in diagnosing aseptic loosening is conventional radiography. Radiolucent lines at the cement-bone or metal-cement interface of more than 2 mm or increasing in translucency, migration of components, and cement fractures are obvious signs of loosening. Artifact-reduced computed tomography can bring additional information regarding periprosthetic osteolysis. A single bone scan is not reliable in diagnosing aseptic loosening, especially in the first 2 years after surgery. Single photon emission computed tomography (SPECT-CT) could be a useful extension in loosening diagnosis in the future.The diagnosis of aseptic loosening poses a great challenge to the treating physician and requires a structured diagnostic algorithm. After exclusion of infection, conventional radiography is the basic examination, which should be supplemented by computed tomography and nuclear medicine examinations according to the clinical symptoms and the time course.HINTERGRUND: Die aseptische Lockerung zählt zu den häufigsten Revisionsgründen in der Knieendoprothetik. Ihre Pathogenese ist multifaktoriell und eine frühzeitige Diagnose ist notwendig, um die entsprechende Therapie einleiten zu können und schwerwiegende Komplikationen, wie frakturgefährdete Osteolysen oder periprothetische Frakturen, zu vermeiden.Die vorliegende Arbeit beschreibt den aktuellen Standard in der Diagnostik der aseptischen Lockerung bei liegender Knietotalendoprothese. Sensitivität und Spezifität der einzelnen diagnostischen Verfahren werden dargestellt und andere Ursachen zur differenzialdiagnostischen Abgrenzung für eine schmerzhafte Knietotalendoprothese (KTEP) diskutiert.Besteht der klinische Verdacht auf eine Lockerung, sollte im Rahmen der Basisdiagnostik eine Infektdiagnostik durchgeführt werden, da dies operationsstrategisch von entscheidender Bedeutung ist. Der Goldstandard in der Lockerungsdiagnostik ist die konventionelle Röntgenaufnahme. Sichere Zeichen für eine Lockerung sind eine mehr als 2 mm messende oder zunehmende durchscheinende Zement-Knochen- oder Metall-Zement-Linie, eine Migration der Komponenten, sowie Zementbrüche. Eine artefaktreduzierte Computertomographie kann zusätzliche Informationen über periprothetische Osteolysen bringen. Nuklearmedizinische Untersuchungen, wie der Knochenscan, sind vor allem in den ersten 2 Jahren nach Primärimplantation meist nicht zuverlässig. Neuere Methoden wie die Single Photon Emission Computed Tomography (SPECT-CT) könnten in Zukunft eine sinnvolle Erweiterung in der Lockerungsdiagnostik sein.Die Diagnostik der aseptischen Lockerung stellt eine große Herausforderung an den behandelnden Arzt dar und erfordert einen strukturierten diagnostischen Algorithmus. Nach erfolgtem Infektausschluss stellt die konventionelle Röntgenaufnahme die Basisuntersuchung dar, die entsprechend der klinischen Symptomatik und dem zeitlichen Verlauf durch eine CT und nuklearmedizinische Untersuchungen ergänzt werden sollte.

Intra-operative fractures in knee revision surgery are relatively rare and have not been well studied. They may occur during joint exposition, removal of the prosthesis or cement, or implantation of trial or original components. The fractures affect both the metaphyseal area and diaphysis of the tibia and femur. Tibial fractures are slightly more common than femur fractures. On the femur, the medial condyle is most frequently affected, followed by the femur diaphysis. The use of non-cemented stems is associated with a greater risk of intra-operative diaphyseal fractures than that of cemented stems. Overall, women and patients with an osteopenic bone structure have a higher risk of fractures. It is common that fractures are diagnosed post-operatively. In these cases, conservative therapy may be successful, depending on the stability of the prosthesis and bones. The most common surgical fixation options are cerclages and screws, followed by stem extensions for bridging the fracture. Plate fixation or use of strut grafts are also sensible therapy options. Overall, intraoperative fractures have a high healing potential with stable and good joint function. The revision rate is still 15%, which is most often caused by peri-prosthetic infection.Intraoperative Frakturen in der Knierevision sind relativ selten und bisher noch wenig untersucht. Sie treten vor allem bei der Exposition des Gelenks, bei der Entfernung der Prothese oder von Zementresten und bei der Re-Implantation von Probe- oder Originalkomponenten auf. Die Frakturen betreffen sowohl den metaphysären Bereich als auch die Diaphyse von Tibia und Femur. Frakturen der Tibia sind etwas häufiger als femorale Frakturen. Am Femur wiederum ist der mediale Kondylus am häufigsten betroffen, gefolgt von der femoralen Diaphyse. Die Verwendung von nicht zementierten Stielen geht gegenüber zementierten Schäften mit einer größeren Gefahr für intraoperative diaphysäre Frakturen einher. Frauen scheinen insgesamt ein höheres Frakturrisiko zu besitzen, genauso wie Patienten mit einer osteopenen Knochenstruktur. Nicht selten werden die Frakturen erst postoperativ diagnostiziert. Eine konservative Therapie ist dann durchaus erfolgreich möglich, in Abhängigkeit der Stabilität von Prothese und Knochen. Die häufigsten operativen Fixationsmöglichkeiten sind Cerclagen und Schrauben, gefolgt von Stielverlängerungen zur Frakturüberbrückung. Plattenosteosynthesen oder die Verwendung von Strut Grafts sind ebenfalls sinnvolle Therapieoptionen. Insgesamt haben intraoperative Frakturen ein hohes Ausheilungspotenzial mit stabiler und guter Gelenkfunktion. Die Re-Revisionsrate liegt dennoch bei 15% und ist am häufigsten durch eine periprothetische Infektion verursacht.

Prior to a surgical intervention, the examination of patient coagulation disorders is unfortunately often underestimated. While patients with a haemophilia A or B are usually aware of the congenital tendency to bleed, disorders of increased blood coagulation, thrombophilia, are frequently undetected. Therefore, complications caused by thromboses and embolisms after total hip arthroplasty are far more common than uncontrollable post-operative bleeding. Patients with liver cirrhosis are considered to be particularly complicated and their coagulation status can be difficult to manage. This article describes the most common pathological coagulation disorders and provides information to identify them preoperatively. Furthermore, surgical strategy considerations for the use of certain implant types in this patient group are discussed.Vor einem operativen Eingriff wird der Untersuchung von Gerinnungsstörungen leider oft nur eine untergeordnete Bedeutung beigemessen. Während Patienten mit einer Hämophilie A oder B i. d. R. die angeborene Blutungsneigung kennen und direkt ansprechen, sind Störungen mit erhöhter Blutgerinnung, die Thrombophilie, dem Patienten häufig gar nicht bekannt. Komplikationen durch Thrombosen und Embolien nach Hüftendoprothesen sind daher weitaus häufiger als unkontrollierbare Nachblutungen. Als besonders komplikationsbehaftet und schwierig im Gerinnungsmanagement gelten Patienten mit Leberzirrhose. Dieser Artikel beschreibt die häufigsten pathologischen Gerinnungsstörungen und gibt Hinweise, um sie präoperativ zu identifizieren. Darüber hinaus werden operationsstrategische Überlegungen für den Einsatz bestimmter Implantattypen in dieser Patientengruppe diskutiert.

Background Patients with osteosynthetic implants around the hip and knee show higher infection rates after joint arthroplasty. Our aim was to evaluate the bacterial colonization of any osteosynthetic implants around the hip and knee in patients without clinical signs of infection. Methods Consecutive patients with osteosynthetic implant removal because of related soft tissue irritations or before elective total joint arthroplasty of the hip and knee were prospectively included. Patients with signs of infection were excluded. Based on sonication fluid cultures, implants were classified according to microbial growth as negative (no growth), contaminated (nonsignificant growth), or colonized (significant growth). Results Sonication cultures were positive in 54 of 203 implants (27%), including 8 of 34 (24%) after orthopedic and 46 of 169 (27%) after traumatological surgery. Of 203 sonication cultures, 22 (11%) grew significant bacterial counts. Most common microorganisms were coagulase-negative staphylococci (46%). Implants around the knee showed a significantly higher rate of positive sonication cultures compared with those around the hip (14% vs 2%, P = .017). Conclusions We detected high bacterial implant colonization rates regardless of the initial type of surgery. Predominant pathogens were staphylococci, the most common causative agents of periprosthetic joint infections. Positive sonication results do not necessarily lead to postoperative surgical complications and thus do not equal infection. It remains unclear if patients with evidence of bacterial implant colonization show a higher risk of periprosthetic joint infection after adjacent subsequent total joint arthroplasty. Nevertheless, surgeons should be aware of a significantly higher colonization rate of implants around the knee and take this into consideration when total knee arthroplasty is scheduled in patients with osteosynthetic devices.

Purpose: In contrast to total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA) is a true resurfacing procedure, as none of the ligaments are replaced or released, and the pre-arthritic leg alignment is the major goal. As such, the alignment of the tibial component plays a crucial role in postoperative knee function and long-term survival. Pinless navigation has shown reliable results in total knee arthroplasty. To the best of our knowledge, the use of pinless navigation has not been investigated for UKA. Therefore, the present study investigated whether implantation of the tibial component in 3° varus, which is closer to the anatomical axis, is feasible with a pinless optical navigation system. Methods: 60 patients with the diagnosis of an unicompartmental arthritis, were eligible for UKA and treated with implantation in 3° varus alignment of the tibial component. Two groups were established. In the treatment group the tibial component was aligned using a pinless navigation technique. In the control group, a conventional extramedullary alignment guide was used. A clinical and radiographic follow up took place within 1 year of operation. Results: 57 Patients were eligible for analysis. No clinical incidents were noted in the follow up period. The desired target value, the position of the tibial component, was accurately achieved with an average of 3° medial inclination using the pinless navigation as well as using the conventional technique. Mean incision to suture time was negligible between the two techniques. The mean suture time was 43.2 min with pinless navigation and 42.7 min with the conventional technique. Conclusions: With pinless navigation in UKA, a method was presented that made it possible to achieve sled prosthesis alignment at the level of a high-volume surgeon. These results were achieved with an irrelevant increase of surgical time and without placement of pins.

Skills training is important in an arthroplasty curriculum and can focus either on "part tasks" or on full procedures. The most commonly used simulations in orthopedics including arthroplasty are anatomic specimens, dry bone models, and virtual or other technology-enhanced systems. A course curriculum planning committee must identify the gaps to address, define what learners need to be able to do, and select the most appropriate simulation modality and assessment for delivery. Each simulation must have a clear structure with learning objectives, steps, and take-home messages. Feedback from learners and faculty must be integrated to improve processes and models for future learning.

Background:. With increasing life expectancy, the demand for knee replacement is continuously rising. Despite the use of antibiotic prophylaxis and improved aseptic surgical techniques, periprosthetic joint infection (PJI) still occurs in 1% to 5% of patients after primary arthroplasty. An open question is the influence of PJI and resulting surgical procedures on the occurrence of long-term complications such as aseptic loosening. Patients needing multiple revision surgeries are especially at risk for decreases in bone mass and damage to the medullary cavity. Thus, we theorized that prior surgeries on the affected knee increase the risk of aseptic loosening in patients with PJI. Methods:. We retrospectively analyzed the cases of 100 patients who underwent total knee replacement exchange surgery as a result of PJI. In addition to clinical, paraclinical, and radiographic examination, we assessed comorbidities and the number of prior surgeries. Results:. Prosthetic survival was drastically decreased after PJI-related revision arthroplasty: during the first 7.3 years after reimplantation, 22% and 16% of all patients had aseptic loosening and recurrent PJI, respectively. The prevalence of aseptic loosening was 27.8% for female and 15.2% for male patients. A significant association between increasing patients’ American Society of Anesthesiologists (ASA) classification and prosthetic failure rates was found, as was a strong correlation between number of prior surgeries and aseptic loosening Conclusions:. In this study, we found notable rates of aseptic loosening and recurrent PJI following PJI-related revision arthroplasty. The difference in the rate of aseptic loosening among male and female patients supports theories of the role of bone metabolism in the development of aseptic loosening. The economic and clinical burdens of prosthetic failure make it paramount to gain a better understanding of bone metabolism in PJI. Additional research should address the need to optimize treatment strategies to increase prosthetic survival. Level of Evidence:. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Surgical risk factors for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA) are the subjects of ongoing research. It is unclear if there are specific locations of the surgical area that might act as a pathogen source. Due to the fact that bacterial replication occurs preferably under humid conditions, it was our aim to investigate if irrigation fluid reservoirs on the surgical covers are subject to bacterial colonization. We prospectively observed 40 patients with scheduled aseptic 1-stage TKA revision. At time intervals of 30 min, irrigation samples were tested for microbiological colonization. Additionally, the suction tip was investigated at the end of surgery. Overall, a bacterial detection rate of 25% was found (57/232 samples). Analysis for any positive microbial detection revealed pathogen findings of irrigation fluid in 41.7% of samples after 30 min with a constant increase up to 77.8% after 90 min. Twenty-three percent of suction tips showed bacterial colonization. Coagulase-negative staphylococci, accounting for the majority of PJI, were the predominant pathogens. After an average follow-up of 17 months, no PJI was confirmed. Despite the substantial bacterial load of irrigation fluid, PJI rates were not elevated. Nevertheless, we recommend that irrigation fluid reservoirs should be prevented and not withdrawn by suction.

We discuss the derivation and the solutions of integro-differential equations (variable-order time-fractional diffusion equations) following as continuous limits for lattice continuous time random walk schemes with power-law waiting-time probability density functions, whose parameters are position-dependent. We concentrate on subdiffusive cases and discuss two situations as examples: A system consisting of two parts with different exponents of subdiffusion, and a system in which the subdiffusion exponent changes linearly from one end of the interval to another one. In both cases we compare the numerical solutions of generalized master equations describing the process on the lattice with the corresponding solutions of the continuous equations, which follow by exact solution of the corresponding equations in the Laplace domain with subsequent numerical inversion using the Gaver-Stehfest algorithm.

Today, lateral closing-wedge osteotomy plays a subordinate role in the therapy algorithms of medial gonarthrosis. The medial opening-wedge osteotomy has become more commonly used in recent years. Nevertheless, the lateral closing-wedge osteotomy should belong to the repertoire of the orthopaedic surgeon who conserves the joint in order to be able to offer the entire spectrum of surgical therapy options. The present chapter describes the indication, patient preparation and radiological planning of the operation as well as the surgical procedure in detail. The most important complications and the postoperative treatment are also explained.

The knee joint center of rotation is altered in the absence of the anterior cruciate ligament, which leads to substantially higher variance in kinematic patterns. To overcome this, total knee arthroplasty (TKA) designs with a high congruency in the lateral compartment have been proposed. The purpose of this study was to analyze the influence of a lateral pivot TKA-design on in-vivo knee joint kinematics. Tibiofemoral motion was retrospectively addressed in 10 patients during unloaded flexion-extension and loaded lunge using single plane fluoroscopy. During the unloaded flexion-extension movement, the lateral condyle remained almost stationary with little rollback at maximum flexion. The medial condyle exhibited anterior translation during the whole flexion cycle. During the loaded lunge movement, a higher degree of rollback compared to the unloaded activity was observed on the lateral condyle, whereas the medial condyle remained almost stationary. The results showed a clear lateral pivot during the unloaded activity, reflective of the implant's geometric characteristics, and a change to a medial pivot and a higher lateral rollback during the weight-bearing conditions, revealing the impact of load and muscle force. It remains unclear if the kinematics with a lateral TKA design could be considered as physiological, due to the limited knowledge available on native knee joint kinematics.

A two-stage exchange is the standard treatment approach for chronic periprosthetic joint infection (PJI). While a 6–8 week interval is commonly used before reimplantation, the optimal length of the prosthesis-free interval has not yet been determined. We evaluated the influence of a short (

Background No regenerative approach has thus far been shown to be effective in skeletal muscle injuries, despite their high frequency and associated functional deficits. We sought to address surgical trauma-related muscle injuries using local intraoperative application of allogeneic placenta-derived, mesenchymal-like adherent cells (PLX-PAD), using hip arthroplasty as a standardized injury model, because of the high regenerative and immunomodulatory potency of this cell type. Methods Our pilot phase I/IIa study was prospective, randomized, double blind, and placebo-controlled. Twenty patients undergoing hip arthroplasty via a direct lateral approach received an injection of 3.0 × 108 (300 M, n = 6) or 1.5 × 108 (150 M, n = 7) PLX-PAD or a placebo (n = 7) into the injured gluteus medius muscles. Results We did not observe any relevant PLX-PAD-related adverse events at the 2-year follow-up. Improved gluteus medius strength was noted as early as Week 6 in the treatment-groups. Surprisingly, until Week 26, the low-dose group outperformed the high-dose group and reached significantly improved strength compared with placebo [150 M vs. placebo: P = 0.007 (baseline adjusted; 95% confidence interval 7.6, 43.9); preoperative baseline values mean ± SE: placebo: 24.4 ± 6.7 Nm, 150 M: 27.3 ± 5.6 Nm], mirrored by an increase in muscle volume [150 M vs. placebo: P = 0.004 (baseline adjusted; 95% confidence interval 6.0, 30.0); preoperative baseline values GM volume: placebo: 211.9 ± 15.3 cm3 , 150 M: 237.4 ± 27.2 cm3 ]. Histology indicated accelerated healing after cell therapy. Biomarker studies revealed that low-dose treatment reduced the surgery-related immunological stress reaction more than high-dose treatment (exemplarily: CD16+ NK cells: Day 1 P = 0.06 vs. placebo, P = 0.07 vs. 150 M; CD4+ T-cells: Day 1 P = 0.04 vs. placebo, P = 0.08 vs. 150 M). Signs of late-onset immune reactivity after high-dose treatment corresponded to reduced functional improvement. Conclusions Allogeneic PLX-PAD therapy improved strength and volume of injured skeletal muscle with a reasonable safety profile. Outcomes could be positively correlated with the modulation of early postoperative stress-related immunological reactions.

Introduction: The aim of this study was to analyse the relationship between bony joint orientation and the distribution of hip musculature. Methods: The bone anatomy of the hip (femoral antetorsion (AT), acetabular anteversion (AV), and combined anteversion (AV/AT)) and the muscle volume of the gluteal muscles and the tensor fasciae latae were analysed bilaterally using computed tomography data of 49 patients. Muscle force direction (MFD) was determined for each muscle. The total MFD of the hip musculature was calculated and then correlated with the bony anatomy. Results: The mean AV, AT, and AV/AT were 21.9° ± 5.9°, 7.22° ± 7.4°, and 29.2° ± 9°, respectively. We found the following mean muscle volumes: gluteus maximus: 780 ± 227 cm3, gluteus medius: 322 ± 82 cm3, gluteus minimus: 85 ± 20 cm3, and tensor fasciae latae: 68 ± 22 cm3. The mean MFD was 18.92° ± 1.29°. We found a uniform distribution of the musculature that was not correlated with the bone anatomy. Conclusion: This study highlights the variability in native acetabular and femoral anatomy and that bone hip anatomy does not correlate with the distribution of hip musculature. Although native acetabular anteversion matches the suggested targets for cup insertion, native combined anteversion is not related to current implant insertion targets. Understanding native muscular anatomy and the alterations that occur with different surgical approaches can serve as an explanatory model for THAs that has become unstable despite the components being implanted within the safe zone.

Clinical reports on meniscal scaffolds seem promising, albeit relatively paucity exists regarding their biomechanical behavior. The aim of the study is to delineate the impact of differing suture materials and the type as well as the temperature of the irrigation fluid on the pull-out strength of a polyurethane meniscal scaffold (Actifit®). 128 specimens were utilized with horizontal sutures and uniaxial load-to-failure testing was performed. We compared two different suture materials—polydioxanone (PDS) and non-absorbable, braided polyester sutures (NABP)—as well as two common irrigation fluids—lactated Ringer’s and electrolyte-free, hypotonic Mannitol-Sorbitol. All specimens were further evaluated according to two different temperatures [room temperature (20 °C) and near-core body temperature (37 °C)]. Mean load-to-failure was 53.3 ± 6.5 N. There was no significant difference between the NABP and the PDS group. Ringer group showed a significantly higher load-to-failure compared to Purisole (P = .0002). This was equivalent for both PDS (P = .0008) and NABP sutures (P = .0008). Significantly higher failure loads could be established for the 37° group (P = .041); yet, this difference was neither confirmed for the PDS or in in the NABP subgroup. Only the subgroup using Purisole at 37° showed significantly higher failure loads compared to 20° (P = .017). This study underlines the potential to improve pull-out strength during implantation of an Actifit® scaffold by alteration of the type of irrigation fluid. Lactated Ringer solution provided the highest construct stability in regard to load-to-failure testing and should be considered whenever implantation of a polyurethane meniscal scaffold is conducted.

ZusammenfassungDer Artikel befasst sich mit 4 wesentlichen Aspekten des perioperativen Managements und deren Relevanz in der Knieendoprothetik. Aufgrund der Anzahl unzufriedener Patienten nach Knieendoprothetik scheint eine Optimierung der Prozesse notwendig. Neben der Patientenvorbereitung, der Mobilisierung, der operativen Technik und Implantatwahl kommt dem perioperativen Management eine bedeutende Rolle zu. Hierzu gehören die Anlage einer Blutsperre, die Verwendung von Drainagen, die Nutzung von Tranexamsäure und die Schmerztherapie. Diese werden im vorliegenden Beitrag ausführlich dargestellt.

Despite the lack of validation, synovial aspiration remains a common practice during 2-stage septic revision total knee arthroplasty (TKA). The goal of this study was to investigate the diagnostic validity of synovial polymethylmethacrylate (PMMA) spacer aspiration of temporary knee arthrodesis to detect persistent periprosthetic joint infection before TKA reimplantation. This retrospective cohort study included 73 consecutive patients who underwent 2-stage septic revision TKA according to a standard protocol. After explantation surgery, including temporary arthrodesis with an intramedullary stabilized PMMA spacer, all patients had synovial aspiration 2 weeks before reimplantation to exclude persistent periprosthetic joint infection. Patients had a 2-week antibiotic holiday before aspiration. Sensitivity and specificity of the synovial PMMA spacer joint aspiration for the detection of periprosthetic joint infection were determined and referenced against intraoperative microbiologic and histologic samples obtained at second-stage surgery. Sensitivity of the synovial PMMA spacer aspiration was 21%. Because of poor diagnostic validity, synovial PMMA spacer aspiration cannot be recommended for routine exclusion of persistent periprosthetic joint infection before TKA reimplantation. Therefore, exclusion of persistent periprosthetic joint infection should be supplemented by other diagnostic methods, and it is not necessary to delay TKA reimplantation for PMMA spacer aspiration. [ Orthopedics. 2017; 40(4):231–234.]

As the aims of changes in total knee arthroplasty (TKA) designs are to reinstate more natural kinematics, the current study evaluated the in vivo kinematics in patients who underwent a cruciate retaining gradually changing femoral radius (“G-CURVE”) against a cruciate retaining conventional changing femoral radius (“J-CURVE”) geometry TKA design. The hypothesis of the study is that the G-CURVE design would allow a substantial increase in the femoral rollback compared to the J-CURVE design. Retrospective study design. Thirty patients were included (G-CURVE, n = 20; J-CURVE, n = 10). Single-plane fluoroscopic analysis and marker-based motion capture gait analysis was performed to analyse dynamic tibiofemoral motion during weight-bearing and unloaded activities at 24 month after index surgery. The analysis of the medial and lateral points on the tibia plateau during the unloaded flexion–extension and the weight-bearing lunge activities revealed a significant difference in femoral rollback in G-CURVE TKA above 60° (p = 0.001) and 30° (p = 0.02) of knee flexion, respectively. Moreover, the lateral condyle of the G-CURVE showed a higher extent of femoral rollback while the lateral condyle of the J-CURVE rolled forward. At 2 years post-operative, the G-CURVE TKA showed significant differences in femoro-tibial translation in comparison with the J-CURVE system, in vivo. The G-CURVE resulted in an increased lateral rollback and simultaneously in an elimination of the paradoxical medial roll-forward present in the J-CURVE design. Moreover, knee kinematics analysis showed significant differences between unloaded and weight-bearing conditions revealing the impact of load and muscle force. The analysis conducted in this study contributes to further understand the principal movement characteristics in widely used older designs in comparison with recently developed concepts to get a better overview on their potential benefits on in vivo kinematics. III.

ZusammenfassungExtragroße zementfreie hemisphärische Pressfit-Pfannen werden als Jumbocups bezeichnet und wurden insbesondere in der letzten Dekade aufgrund ihrer einfachen Implantationstechnik häufig bei großen knöchernen Defekten eingesetzt. Durch ihre Größe füllen die Komponenten die azetabulären Defekte jedoch nur aus und tragen somit nicht zur Regeneration des knöchernen Lagers bei. Aufgrund dessen sind gerade bei diesem Implantattyp die Langzeitüberlebensraten von großem Interesse. Der vorliegende Beitrag diskutiert die zu diesem Thema vorliegende, relevante Literatur und geht auf die Operationstechnik und implantatspezifische Besonderheiten von Jumbocups ein. Jumbocups zeigen ein gutes Langzeitüberleben wobei dennoch die aseptische Lockerung die häufigste Revisionsursache und die Luxation die häufigste Komplikation darstellt. Durch die Entwicklung von alternativen meist modularen Revisionssystemen haben Jumbocups in der täglichen Praxis an Bedeutung verloren. Sie sind aber definitiv eine Benchmark für Neuentwicklungen im Bereich der Hüftendoprothetik.

Background In end-stage medial osteoarthritis, the surgeon can decide whether to use unicompartmental or total knee arthroplasty for operative treatment of the patient. Despite the available literature there is a lack of evidence to suggest if one procedure can be rated as being superior to the other. With increasing demand for knee arthroplasty, treatment with the highest expectation of success will be of particular interest. The purpose of this manuscript was to analyse and compare the available literature on unicompartmental vs. total knee arthroplasty for the treatment of medial osteoarthritis. Material and Methods In this review of literature, the two procedures were compared regarding their clinical outcome, implant survival, and complication rates. Results Regarding the clinical outcome the unicompartmental knee arthroplasty was shown to be superior over total knee arthroplasty. However, studies were mostly retrospective and groups were also different preoperatively. Patients treated with unicompartmental knee arthroplasty had better preoperative range of motion and function scores. Unicompartmental and total knee arthroplasty showed comparably increased functional scores. Taking the implant survival as parameter, institutional registries, multicenter studies and arthroplasty registries found total knee arthroplasties to have a significantly better long-term survival in comparison to unicompartmental knee arthroplasty. However, data might be biased by the lower threshold to revise unicompartmental knee arthroplasty due to expected simple revision and more subjective indications for revision. Looking at the complication rate, one has to differentiate between general and implant-specific complications. While the unicompartmental knee arthroplasty was shown to be advantageous in terms of general complications and mortality, it was also shown to be inferior in terms of implant-specific complications. Conclusion The available literature does not show one procedure to be superior to the other. The trend to a better clinical outcome and a lower mortality rate is advantageous for unicompartmental knee arthroplasty, while the better long-term survival and a lower risk of implant-specific complications may make total knee arthroplasty preferable.

Severe injury to the skeletal muscle often results in the formation of scar tissue, leading to a decline in functional performance. Traditionally, tissue engineering strategies for muscle repair have focused on substrates that promote myogenic differentiation of transplanted cells. In the current study, the reported data indicates that mesenchymal stromal cells (MSCs) transplanted via porous alginate cryogels promote muscle regeneration by secreting bioactive factors that profoundly influence the function of muscle progenitor cells. These cellular functions, which include heightened resistance of muscle progenitor cells to apoptosis, migration to site of injury, and prevention of premature differentiation are highly desirable in the healing cascade after acute muscle trauma. Furthermore, stimulation of MSCs with recombinant growth factors IGF-1 and VEGF165 was found to significantly enhance their paracrine effects on muscle progenitor cells. Multifunctional alginate cryogels were then utilized as synthetic niches that facilitate local stimulation of seeded MSCs by providing a sustained release of growth factors. In a clinically relevant injury model, the modulation of MSC paracrine signaling via engineered niches significantly improved muscle function by remodeling scar tissue and promoting the formation of new myofibers, outperforming standalone cell or growth factor delivery.

Standing long-leg radiographs allow assessment of the mechanical axis in the frontal plane before and after total knee arthroplasty (TKA). An alteration in loading, and hence in the forces acting on the knee joint, occurs postoperatively. We therefore postulated that the mechanical axis measured in the long-leg standing radiograph would change within the first year after TKA.Standing long-leg radiographs of 156 patients were performed 7 days, 3 months, and 12 months after TKA with determination of mechanical axis of the lower limb.Seven days after surgery, the mechanical axis amounted 0.8° ± 1.7° valgus. Three months after the operation, at 1.3° ± 1.3° varus, it was significantly different (P.001) from the primary measurement. No further alteration in the mechanical axis occurred during the first year after TKA. This difference was even more pronounced (P.001) in patients with a postoperative lack of complete extension. Seven days after surgery, they had a valgus axis deviation of 1.6° ± 1.6°; after 3 months, the measurement amounted 1.2° ± 1.3° varus.Measured by a standing long-leg radiograph, the frontal mechanical axis after TKA changes over time. The predictive power of a standing long-leg radiograph in the first week after surgery is limited because limb loading is altered because of pain and is therefore nonphysiological. The actual mechanical axis resulting after TKA can only be assessed in a standing long-leg radiograph at physiological loading.

Local infiltration anaesthesia (LIA) was introduced as an innovative analgesic procedure for enhanced recovery after primary total knee arthroplasty (TKA). However, LIA has never been compared with analgesia based on an adductor canal catheter and a single-shot sciatic nerve block.To evaluate two analgesic regimens for TKA comparing mobility, postoperative pain and patient satisfaction.Two-group randomised, controlled clinical trial.Charité-Universitätsmedizin Berlin, Campus Charité Mitte, Germany between April and August 2017.Adults undergoing primary TKA under general anaesthesia were eligible for study participation. Exclusion criteria were heart insufficiency (New York Heart Association class2), liver insufficiency (Child Pugh ScoreB), evidence of diabetic polyneuropathy, severe obesity (BMI 40 kg m), chronic opioid therapy for more than 3 months before scheduled surgery and allergy to local anaesthetics.Nerve block patients group (n=20) underwent surgery with two ultrasound-guided regional anaesthesia blocks: a single-shot sciatic nerve block with 20 ml of ropivacaine 0.75% combined with an adductor canal block with a catheter placed for less than 4 days with an infusion of ropivacaine 0.2% at a rate of 6 ml h. LIA patients (LIA group, n=20) received LIA of the knee capsule at the end of surgery with 150 ml of ropivacaine 0.2%.The primary endpoint was postoperative time to patient mobilisation (ability to walk) on the ward.Baseline characteristics were similar in each study group. Patients in both groups were mobilised to walk after TKA in similar time frames (LIA 24.0 h versus nerve block 27.1 h, 95% CI of difference -9.6 to 3.3 h). Maximum postoperative pain scores on exertion were higher in LIA patients with a mean 1.3 of 10 numerical rating scale points (95% CI 0.3 to 2.3, P = 0.010) as were intra-operative opioid requirements (LIA median 107 [IQR 100 to 268] mg versus nerve block median 78 [60 to 98] mg, P 0.001). Patient satisfaction, postoperative oral morphine-equivalents and resting pain levels were comparable between groups. Anaesthesia induction time was reduced in LIA patients (LIA 10 min versus nerve block 35 min, 95% CI of difference 13 to 38 min, P 0.001).Both analgesic regimens allow early mobilisation after TKA with high patient satisfaction. LIA shortened peri-operative time. Further research is required to optimise especially pain control during the later postoperative period with LIA.Clinicaltrials.gov identifier NCT03114306.

BackgroundNo regenerative approach has thus far been shown to be effective in skeletal muscle injuries, despite high frequency and associated functional deficits. We sought to address surgical trauma related muscle injuries using local intraoperative application of allogeneic placenta-derived, mesenchymal-like adherent cells (PLX-PAD), using hip arthroplasty as a standardized injury model, because of the high regenerative and immunomodulatory potency of this cell type.MethodsOur pilot phase I/IIa study was prospective, randomized, double blind and placebo-controlled. Twenty patients undergoing hip arthroplasty via a direct lateral approach were injected with 3.0×108or 1.5×108PLX-PAD or a placebo into the gluteus medius muscle.ResultsWe did not observe any relevant PLX-PAD-related adverse events at the 2-year follow-up. Improved gluteus medius strength was noted as early as week 6 in the treatment-groups. Surprisingly, until week 26 the low-dose outperformed the high-dose group and reached significantly improved strength compared to placebo, mirrored by an increase in muscle volume. Histology indicated accelerated healing after cell therapy. Biomarker studies revealed that low-dose treatment reduced the surgery-related immunological stress reaction more than high-dose. Signs of late-onset immune reactivity after high-dose treatment corresponded to reduced functional improvement.ConclusionAllogeneic PLX-PAD therapy improved strength and volume of injured skeletal muscle with a reasonable safety profile. Outcomes could be positively correlated with the modulation of early postoperative stress-related immunological reactions.Trial RegistrationClinicalTrials.gov(numberNCT01525667) and EudraCT (number 2011-003934-16)FundingThe study was funded by the Sponsor, Pluristem Therapeutics, the Israeli innovation authority and the German Federal Ministry of Education and Research.Conflict of interestT. Winkler, C. Perka and G.N. Duda are members of a clinical advisory board of Pluristem Ltd for future indications. T. Winkler, C. Perka, G.N. Duda, P. von Roth filed a patent together with Pluristem Ltd. E. Lukasiewicz Hagai, R. Ofir, L. Pinzur and E. Eyal are current or former employees of Pluristem Ltd. T. Winkler, P. Reinke and H.-D. Volk received in the past consulting fees from Pluristem Ltd. but not for this project.

Revision of total knee arthroplasty (TKA) is growing rapidly all over the world. The introduction of intramedullary stems for additional stability in revision is well accepted by most of the surgeons, while the philosophy of stem fixation is still under controversy. A meta-analysis was performed to compare the survivorship of revised implants with regard to a cemented or cementless stem fixation. Publications with patients who underwent revision TKA with minimum 24-month follow-up were systematically reviewed. Type of intramedullary stem fixation, failure rate for any reason, incidence of aseptic loosening and infection were extracted with follow-up interval specified. Random-effects meta-analysis was used to aggregate incidence data, which was compared between different fixation groups by fitting of logistic regression model. Seventeen observational studies were included in this meta-analysis. There was a similar likelihood of failure for any reason (risk ratio, RR 0.97), general reoperation (RR 1.02), aseptic loosening (RR 1.0) and infection (RR 1.0) in cemented stem fixation group compared to cementless stem fixation group with follow-up

Background Displaced femoral neck fractures frequently are treated with bipolar hemiarthroplasties. Despite the frequency with which bipolar hemiarthroplasty is used to treat these fractures, there are few long-term data.

Implants of microporous β-tricalcium phosphate (β-TCP) were developed for primarily stable supply of bone defects. A consistent stability over the healing period should be retained in sheep. β-TCP cylindrical shaped implants, with 7 mm diameter, 25 mm length, medium pore diameter 5 μm and 40% porosity were developed. Fresh bone defects of 21 sheep in the medial femur condyle were filled with the implants. At time zero, after 6, 12 and 24 weeks the knees of each 7 animals were studied. Specimens were investigated radiologically, followed by biomechanical and histological analysis. Radiological analysis showed progressive resorption. 6 weeks after surgery results of the indentation test were slightly lower, after 12 and 24 weeks higher than on the healthy opposite knee. At 6 weeks a phagocyte reaction overbalanced. After 12 weeks bone regeneration around the implant was seen. After 24 weeks a highly advanced resorption of TCP implant was realized. The trabecular structure of the new bone increased after 24 weeks. Using microporous β-TCP implants continuous stable filling of bone defects can be reached in sheep. Microporous β-TCP implants are resorbed and replaced by bone.

Acetabular fractures increase the risk of posttraumatic arthritis and thus the risk of total hip arthroplasty (THA). We previously presented the ten-year results of THA performed for posttraumatic arthritis after an acetabular fracture; we now present the twenty-year outcomes. The original publication included sixty-six patients who underwent THA between 1970 and 1993 for posttraumatic arthritis after open reduction and internal fixation (ORIF) of an acetabular fracture. Clinical outcomes, implant survivorship, radiographic results, and complications were evaluated. A total of thirty-six patients had died. The mean Harris hip score was 80 at the latest follow-up. Nineteen acetabular and/or femoral components had been revised: eleven for aseptic loosening, seven for osteolysis, and one for instability. Twenty-year survivorship of the acetabular component was 71% free from revision for aseptic loosening and 57% free from revision for any reason. THA after ORIF of an acetabular fracture was associated with fair implant survivorship at twenty years after surgery. It is possible that newer implants with improved fixation surfaces and bearing materials may enhance long-term results, as the most common reasons for failure at twenty years were aseptic loosening and osteolysis.

The themes of this paper are the clinical relevance and technique of perioperative management in total knee arthroplasty. Due to the number of unsatisfied patients after knee arthroplasty, optimisation of processes seems to be necessary. Beside patient preparation and rehabilitation, the surgical technique and implant choice in perioperative management are important. This means the use of tourniquet and drains, the application of tranexamic acid and pain management. These items are presented and discussed in detail in this paper.Der Artikel befasst sich mit 4 wesentlichen Aspekten des perioperativen Managements und deren Relevanz in der Knieendoprothetik. Aufgrund der Anzahl unzufriedener Patienten nach Knieendoprothetik scheint eine Optimierung der Prozesse notwendig. Neben der Patientenvorbereitung, der Mobilisierung, der operativen Technik und Implantatwahl kommt dem perioperativen Management eine bedeutende Rolle zu. Hierzu gehören die Anlage einer Blutsperre, die Verwendung von Drainagen, die Nutzung von Tranexamsäure und die Schmerztherapie. Diese werden im vorliegenden Beitrag ausführlich dargestellt.

Clinical reports on meniscal scaffolds seem promising, albeit relatively paucity exists regarding their biomechanical behavior. The aim of the study is to delineate the impact of differing suture materials and the type as well as the temperature of the irrigation fluid on the pull-out strength of a polyurethane meniscal scaffold (Actifit128 specimens were utilized with horizontal sutures and uniaxial load-to-failure testing was performed. We compared two different suture materials-polydioxanone (PDS) and non-absorbable, braided polyester sutures (NABP)-as well as two common irrigation fluids-lactated Ringer's and electrolyte-free, hypotonic Mannitol-Sorbitol. All specimens were further evaluated according to two different temperatures [room temperature (20 °C) and near-core body temperature (37 °C)].Mean load-to-failure was 53.3 ± 6.5 N. There was no significant difference between the NABP and the PDS group. Ringer group showed a significantly higher load-to-failure compared to Purisole (P = .0002). This was equivalent for both PDS (P = .0008) and NABP sutures (P = .0008). Significantly higher failure loads could be established for the 37° group (P = .041); yet, this difference was neither confirmed for the PDS or in in the NABP subgroup. Only the subgroup using Purisole at 37° showed significantly higher failure loads compared to 20° (P = .017).This study underlines the potential to improve pull-out strength during implantation of an Actifit

Extra-large uncemented jumbo cups are among the most common methods of acetabular revision. Jumbo cups do not contribute to bone stock restoration, and in the case of a subsequent revision, an even larger bone defect is to be expected. Thus, understanding long-term survival is essential. The present article discusses the literature relevant to this topic and addresses technical and implant-specific characteristics of jumbo cups. In summary, jumbo cups show an acceptable long-term survival rate, with aseptic loosening as the most common reason for revision and dislocation being the most common complication. Through the development of alternative revision systems, jumbo cups have lost their importance in today's practice. However, they can serve as a benchmark for studies of newer technologies in revision total hip arthroplasty.Extragroße zementfreie hemisphärische Pressfit-Pfannen werden als Jumbocups bezeichnet und wurden insbesondere in der letzten Dekade aufgrund ihrer einfachen Implantationstechnik häufig bei großen knöchernen Defekten eingesetzt. Durch ihre Größe füllen die Komponenten die azetabulären Defekte jedoch nur aus und tragen somit nicht zur Regeneration des knöchernen Lagers bei. Aufgrund dessen sind gerade bei diesem Implantattyp die Langzeitüberlebensraten von großem Interesse. Der vorliegende Beitrag diskutiert die zu diesem Thema vorliegende, relevante Literatur und geht auf die Operationstechnik und implantatspezifische Besonderheiten von Jumbocups ein. Jumbocups zeigen ein gutes Langzeitüberleben wobei dennoch die aseptische Lockerung die häufigste Revisionsursache und die Luxation die häufigste Komplikation darstellt. Durch die Entwicklung von alternativen meist modularen Revisionssystemen haben Jumbocups in der täglichen Praxis an Bedeutung verloren. Sie sind aber definitiv eine Benchmark für Neuentwicklungen im Bereich der Hüftendoprothetik.

Background: Reliable acetabular fixation in total hip arthroplasty following periacetabular resections is challenging. Tantalum components have been successfully implemented for difficult revision arthroplasties, but, to our knowledge, have not been reported for acetabular reconstruction following oncologic periacetabular resection. The primary purpose of the current study was to determine the early clinical outcomes, complications, and radiographic findings for acetabular reconstruction after oncologic periacetabular resection. In addition, a novel classification scheme for primary periacetabular resections and reconstructions is presented. Methods: We reviewed 10 consecutive patients treated with tantalum acetabular reconstruction following periacetabular resection. All patients had a primary acetabular malignancy including chondrosarcoma (n = 7) and osteosarcoma (n = 3). The cohort included 6 males (60%). The mean age was 54 years (range, 30 to 73 years). The mean follow-up was 59 months (range, 8 to 113 months). Results: At the most recent follow-up, 9 patients were alive and 1 had died of the respective disease. All patients obtained full ambulatory status with the use of gait aids. Postoperative complications included dislocation (n = 3), wound-healing disturbance (n = 1), and deep venous thrombosis (n = 1). Two patients underwent reoperations for recurrent dislocations. The mean postoperative Harris hip score was 75 points (range, 49 to 92 points). Conclusions: Preliminary results of tantalum reconstruction following periacetabular resections provide reasonable improvement in early clinical outcomes and stable fixation in situations with massive bone loss and compromised bone quality. As expected due to the lack of a functioning abductor mechanism from the wide oncologic resection, early dislocations remain a concern. As such, we now consider the primary use of increasing constraint, but it must be balanced with the often compromised host bone. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.