The Safety of Bilateral Simultaneous Hip and Knee Arthroplasty versus Staged Arthroplasty in a High-Volume Center Comparing Blood Loss, Peri- and Postoperative Complications, and Early Functional Outcome.

Purpose: In recent years, there has been increasing interest in the use of simultaneous hip and knee arthroplasty compared to staged procedures in patients with bilateral pathology. The aim of this study was to compare simultaneous and staged hip and knee arthroplasty in patients with bilateral pathology by assessing the transfusion rate, postoperative hemoglobin drop, length of stay (LOS), in-hospital complications, 30-day readmissions and early functional outcome.

Methods: We conducted a retrospective cohort study that included all patients who were undergoing primary TKA, THA and UKA by a single surgeon in a high-volume arthroplasty center between 2015 and 2020 as simultaneous or staged procedures.

Efficacy of antibiotic treatment of implant-associated infections with moxifloxacin, flucloxacillin, rifampin, and combination therapy: an animal study.

The efficacy of antibiotic monotherapy and combination therapy in the treatment of implant-associated infection by was evaluated in an animal study. The femoral medullary cavity of 66 male Wistar rats was contaminated with (ATCC 29213) and a metal device was implanted, of which 61 could be evaluated. Six treatment groups were studied: flucloxacillin, flucloxacillin in combination with rifampin, moxifloxacin, moxifloxacin in combination with rifampin, rifampin, and a control group with aqua.

The role of the transverse acetabular ligament for acetabular component orientation in total hip replacement: an analysis of acetabular component position and range of movement using navigation software.

Orientation of the native acetabular plane as defined by the transverse acetabular ligament (TAL) and the posterior labrum was measured intra-operatively using computer-assisted navigation in 39 hips. In order to assess the influence of alignment on impingement, the range of movement was calculated for that defined by the TAL and the posterior labrum and compared with a standard acetabular component position (abduction 45°/anteversion 15°). With respect to the registration of the plane defined by the TAL and the posterior labrum, there was moderate interobserver agreement (r = 0.

[Extension first technique for TKA implantation].

Objective: Surgical technique in total knee arthroplasty (TKA) to combine the femur first and tibia first techniques in order to reduce surgical mistakes regarding rotation and alignment.

Indications: Symptomatic arthritis of the knee.

Contraindications: General contraindications for TKA.

Validation of a measurement device for instrumented quantification of anterior translation and rotational assessment of the knee.

Purpose: A test setup for clinical use in the awake and non-anesthetized patient measuring anteroposterior translation and rotation of the knee joint is the subject of validation.

Methods: A measuring device featuring fixation of the foot at 30° of knee flexion with varus/valgus stress posts for the knee was developed. Tibial rotation (external/internal) was imposed with a torque of 2 Nm on the footrest with the ankle locked in dorsiflexion.

[TKA revision of semiconstraint components using the 3-step technique].

Objective: The surgical goal is to achieve a pain free and stable knee joint after revision total knee arthroplasty in three steps. An important component of the technique is the reproducible restoration of the joint line.

Indications: Revision total knee arthroplasty.

Accuracy of acetabular cup placement in computer-assisted, minimally-invasive THR in a lateral decubitus position.

In a prospective and randomised clinical study, we implanted acetabular cups either by means of an image-free computer-navigation system (navigated group, n = 32) or by free-hand technique (freehand group n = 32, two drop-outs). Total hip replacement was conducted in the lateral position and through a minimally invasive anterior approach (MicroHip). The position of the component was determined postoperatively on CT scans of the pelvis using CT-planning software.

[Toxicity of antiseptics on chondrocytes in vitro].

Aim: Local antiseptics are commonly used for perioperative skin and wound disinfection and as solutions for joint lavage. Therefore, we examined if an intra-articular use of these antiseptics is possible by using an IN VITRO chondrocyte model.

Material And Methods: Articular chondrocytes harvested from 7 patients were cultured.

Experimental validation of a pinless femoral reference array for computer-assisted hip arthroplasty.

The use of computer navigation systems during total hip arthroplasty requires the femoral fixation of a reflective dynamic reference base (DRB), which theoretically involves the risk of bony fracture, infection, and pin loosening. The first objective of this study was to evaluate the relative movements between a novel, noninvasive external femoral DRB system and the femur. Secondly, the maximum effects of these 3D movements on intraoperative, computer-assisted leg length and offset measures were evaluated.

Leg length and offset measures with a pinless femoral reference array during THA.

The bony fixation of reference marker arrays used for computer-assisted navigation during total hip arthroplasty (THA) theoretically involves the risk of fracture, infection, and/or pin loosening. We asked whether intraoperative assessment of leg length (LL) and offset (OS) changes would be accurate using a novel pinless femoral reference system in conjunction with an imageless measurement algorithm based on specific realignment of the relationship between a dynamic femoral and pelvis reference array. LL/OS measurements were recorded during THA in 17 cadaver specimen hips.

Computer-assisted total hip arthroplasty: coding the next generation of navigation systems for orthopedic surgery.

This article outlines the scientific basis and a state-of-the-art application of computer-assisted orthopedic surgery in total hip arthroplasty (THA) and provides a future perspective on this technology. Computer-assisted orthopedic surgery in primary THA has the potential to couple 3D simulations with real-time evaluations of surgical performance, which has brought these developments from the research laboratory all the way to clinical use. Nonimage- or imageless-based navigation systems without the need for additional pre- or intra-operative image acquisition have stood the test to significantly reduce the variability in positioning the acetabular component and have shown precise measurement of leg length and offset changes during THA.

Measuring leg length and offset with an imageless navigation system during total hip arthroplasty: is it really accurate?

Background: A novel imageless measurement algorithm to assess leg length (LL) and offset (OS) changes during total hip arthroplasty (THA) has been established, the purpose of this study was to describe the process and establish whether or not it is accurate.

Methods: THA was performed on 17 cadaver hip specimens. LL and OS changes were determined intra-operatively, using an imageless navigation system.

Accuracy of imageless stem navigation during simulated total hip arthroplasty.

Background And Purpose: New computer-assisted measurement algorithms have been established to support the surgeon during total joint replacement intraoperatively. We asked whether the assessment of leg length and offset measured with an imageless navigation system is reliable during simulated total hip arthroplasty in a sawbone model test bench.

Methods And Results: We found no statistically significant difference between change in leg length and offset measured on a millimeter scale connected to the test bench and that obtained with the calculation algorithm of the imageless navigation system.

In vitro investigation of the influence of pelvic tilt on acetabular cup alignment.

This study investigates the influence of pelvic tilt on conventional alignment of acetabular cups. Cementless cups were aligned into a synthetic replica of the pelvis 300 times at different pelvic tilts. At +10 degrees pelvic tilt, average cup inclination was 46.

Tissue concentrations of vancomycin and Moxifloxacin in periprosthetic infection in rats.

Background: A one-step exchange of an endoprosthesis with periprosthetic infection requires effective antibiotics at high concentrations around the endoprosthesis. We evaluated the tissue distribution of vancomycin and Moxifloxacin in a standardized in vivo model of periprosthetic infection.

Methods: 36 male rats with periprosthetic infection of the left hind leg, induced by a standardized procedure, received either antibiotic treatment with vancomycin or Moxifloxacin twice daily for 2 weeks, or a sham treatment.

An experimental comparison of different devices for pulsatile high-pressure lavage and their relevance to cement intrusion into cancellous bone.

Introduction: Some of the systems marketed for pulsatile high-pressure lavage are clearly different in their mechanical pulse characteristics. To take the matter further we set up an experimental in vitro model to determine whether these different lavage systems might produce different cementation results because of their differing pulse characteristics, and whether the systems differed significantly in terms of cement depth penetration.

Materials And Methods: A total of 48 femoral heads were obtained at operation from patients who had undergone endoprosthetic hip replacement.

Moxifloxacin superior to vancomycin for treatment of bone infections--a study in rats.

Background: Increasing resistance rates towards conventional antibiotics necessitate investigations of the efficacy of newly developed antibiotics. Thus, in a rat study, we compared the efficacy of moxifloxacin and vancomycin in the treatment of a local Staphylococcus aureus bone infection.

Method: The femoral medullary cavities of 36 Wistar rats were contaminated with 100 muL of an oxacillin-sensitive Staphylococcus aureus strain (ATCC 29213) at 10(8) cfu/mL.

Precision of computer-assisted core decompression drilling of the femoral head.

Introduction: Osteonecrosis of the femoral head is a local destructive disease with progression into devastating stages. Left untreated it mostly leads to severe secondary osteoarthrosis and early endoprosthetic joint replacement. Core decompression by exact drilling into the ischemic areas can be performed in early stages according to Ficat or ARCO.

Precision of computer-assisted core decompression drilling of the knee.

Introduction: Core decompression by exact drilling into the ischemic areas is the treatment of choice in early stages of osteonecrosis of the femoral condyle. Computer-aided surgery might enhance the precision of the drilling and lower the radiation exposure time of both staff and patients. The aim of this study was to evaluate the precision of the fluoroscopically based VectorVision-navigation system in an in vitro model.

Treatment of implant-associated infections with moxifloxacin: an animal study.

The efficacy of moxifloxacin in the treatment of an implant-associated infection by Staphylococcus aureus was compared with vancomycin in an animal study. The femoral medullary cavity of 36 Wistar rats was contaminated with S. aureus (ATCC 29213) and a metal device was implanted.

[Postoperative autologous retransfusion of collected shed blood after total knee arthroplasty with the cell saver].

Aim: The purpose of this study was to examine if it is possible to reduce transfusion of blood units by collecting shed blood with the Cell Saver for autologous retransfusion in total knee arthroplasty (TKA).

Method: In 186 patients drainage blood was collected over a 6-h period after total knee arthroplasty with a Cell Saver system in order to make retransfusions if necessary. A tourniquet was used routinely throughout the operation.

Imageless navigation for insertion of the acetabular component in total hip arthroplasty: is it as accurate as CT-based navigation?

In a prospective randomised clinical study acetabular components were implanted either freehand (n = 30) or using CT-based (n = 30) or imageless navigation (n = 30). The position of the component was determined post-operatively on CT scans of the pelvis. Following conventional freehand placement of the acetabular component, only 14 of the 30 were within the safe zone as defined by Lewinnek et al (40 degrees inclination sd 10 degrees ; 15 degrees anteversion sd 10 degrees ).

Position of the acetabular cup -- accuracy of radiographic calculation compared to CT-based measurement.

Objective: A variety of mathematical and trigonometric methods has been described for determining the position of the acetabular cups from conventional radiographs. However, these formulae are subject to unduly large inaccuracies. The aim of the study was to compare the reliability and the accuracy of radiological and CT-based determination of acetabular cup position.

Contaminant seeding in bone by different irrigation methods: an experimental study.

Objective: This study was designed to investigate the effectiveness of using various devices and manual procedures for cleansing bacterially contaminated bone tissue and to assess the risk of iatrogenic bacterial seeding in deep bone layers.

Methods: In an in vitro model, human femoral heads were contaminated with Escherichia coli and then cleansed with pulsatile high-pressure lavage, pulsatile low-pressure lavage, manual rinsing with bulb syringe lavage, or manual rinsing with combined brush cleaning. The numbers of bacteria that remained or those that were introduced by the rinsing procedures were quantitatively determined at depths of 0 to 1 cm, 1 to 2 cm, and 2 to 3 cm.

[Changes in muscle torque in patients after total knee arthroplasty].

Aim: The purpose of this study was to compare muscle torque during isokinetic knee movements of patients after total knee arthroplasty (TKA) with a similar healthy group.

Method: 43 patients were examined 3 years after primary total knee arthroplasty with an isokinetic dynamometer (Cybex 340). Torque measurements were evaluated for extension and flexion with 4 different velocities.