Femoral cement extraction in revision total hip arthroplasty--an in vitro study comparing computer-assisted freehand-navigated cement removal to conventional cement extraction.

Background: Revision surgery of cemented femoral stems in total hip arthroplasty is gaining more and more importance, but cement removal in revision hip arthroplasty may be technically challenging. Conventional manual cement removal can be time consuming and be associated with complications such as cortical perforation, fracture, or bone loss. The aim of this study was to investigate the practicability of computer-navigated cement removal.

[Metaphyseal fitting short-stem prosthesis - preliminary results of a prospective single-surgeon series].

Background: Conventional uncemented femoral stems provide good long-term fixation in patients with a wide range of clinical function. However, preservation of bone stock, and minimally invasive approaches have led to exploration into various other implant designs. Short-stem prosthesis focusing on a stable metaphyseal fit have emerged to address these challenges in total hip arthroplasty.

Endoglin (CD105) expression differentiates between aseptic loosening and periprosthetic joint infection after total joint arthroplasty.

The differentiation between aseptic loosening and periprosthetic joint infection (PJI) after total joint arthroplasty is essential for successful therapy. A better understanding of pathogenesis of aseptic loosening and PJI may help to prevent or treat these complications. Previous investigations revealed an increased vascularization in the periprosthetic membrane in cases of PJI via PET signals.

Cell-free repair of small cartilage defects in the Goettinger minipig: which defect size is possible?

Purpose: Cartilage repair of full-thickness chondral defects in the knees of Goettinger minipigs was assessed by treatment with cell-free collagen type-I gel plugs of three different sizes.

Methods: In 6 adult Goettinger minipigs, three full-thickness chondral defects were created in the trochlear groove of one knee of the hind leg. These defects were treated with a cell-free collagen type-I gel plug of 8, 10, or 12 mm diameter.

Condensed cellular seeded collagen gel as an improved biomaterial for tissue engineering of articular cartilage.

Three-dimensional autologous chondrocyte implantation based on collagen gel as matrix scaffold has become a clinically applied treatment for focal defects of articular cartilage. However, the low biomechanical properties of collagen gel makes intraoperative handling difficult and creates the risk of early damages to the vulnerable implant. The aim of the study was to create a stabilized form of collagen gel and to evaluate its biomechanical and biochemical properties.

Trackerless ultrasound-integrated bone cement detection using a modular minirobot in revision total hip replacement.

Medical robots are superior to freehand manipulation if an accurate, precise, and time-efficient implementation of a preplanned intervention is required. In the first part of this contribution a new modular minirobot for automatic ultrasound-based bone cement detection followed by subsequent cement milling in revision total hip replacement is presented. A minirobot integrated ultrasound module eliminates the need for external position tracking (e.

[Periprosthetic bone cement allocation at the femoral durom hip prosthesis. a pilot study: artificial bone models versus ex-vivo femura].

Introduction: Despite controversial discussions, hip resurfacing at the moment seems to be the most bone-sparing surgical procedure of the femoral bone when implanting hip endoprostheses. Main risks are septic and aseptic loosening and necroses of the coxal end of the femoral bone mainly influenced by the periprosthetic allocation of bone cement. Because of a lack of radiation transparency of the hip resurfacing implant, this cement allocation cannot be sufficiently evaluated by common radiological procedures.

Evaluation of a new fluoroscopy-based navigation system in the placement of the femoral component in hip resurfacing.

Prosthesis-specific mechanical alignment instruments for the precise and reproducible positioning of the femoral component constitute one of the major improvements in modern hip resurfacing prostheses. However, mechanical failure of the femoral component is mostly attributable to the surgical technique, and in particular to notching of the femoral neck. In order to evaluate a novel computer-assisted fluoroscopy-based planning and navigation system, six DUROM hip resurfacing prostheses were implanted into artificial femurs by means of computer-assisted fluoroscopy-based navigation and prosthesis-specific mechanical alignment instruments.

A cell-free collagen type I device for the treatment of focal cartilage defects.

The purpose of this study was to evaluate the potential value of a cell-free collagen type I gel plug for the treatment of focal cartilage defects. Cellular migration and proliferation was addressed in vitro, and the formation of repair tissue in a nude mouse-based defect model. A cell-free plug made of collagen type I was placed in the center of an incubation plate.

[Analysis of 18F-FDG uptake pattern in PET for diagnosis of aseptic loosening versus prosthesis infection after total knee arthroplasty. A prospective pilot study].

Unlabelled: The AIM of this prospective study was to identify a typical pattern for fluorodeoxyglucose (18F-FDG) uptake in positron emission tomography (PET) to differentiate aseptic loosening (tibial and / or femoral component) from prosthesis infection in painful knee prosthesis.

Patients, Methods: 20 patients with painful knee prosthesis underwent PET imaging to evaluate aseptic loosening / prosthesis infection of their knee prosthesis. The interface between bone and surrounding soft tissue or bone was divided into 3 segments each for both the femur and the tibia and in addition for 4 segments reflecting the surrounding periprosthetic soft tissue.

[Evaluation of the efficiency of the zero-dose-C-arm navigation approach].

Background: The efficiency and success of computer-assisted fluoroscopic navigation systems mainly depend on the quality of the process of image acquisition: obtaining the correct view of anatomic structures, relative orientation of multiplanar X-ray images and the necessary amount of radiation dose. These systems may be optimised by using a system called zero-dose c-arm navigation (ZDCAN). We investigate whether the available computer-assisted systems may be used to navigate the c-arm before image acquisition to obtain X-ray images with maximised accuracy and minimal radiation exposure.

[Perioperative management in outpatient arthroscopy of the knee joint].

Aim: Nowadays, complex arthroscopic procedures of the knee joint, such as ACL reconstruction, are routinely carried out on an outpatient basis. The reduced time spent with the patient places high demands on the surgeon with regard to the management of such cases. The aim of this study was to evaluate the current standards of perioperative management following outpatient arthroscopic surgery of the knee in Germany.

[Surgical principles and clinical experiences with the DUROM hip resurfacing system using a lateral approach].

Objective: Objective Bone-preserving hip resurfacing in young and active patients using a soft-tissue-sparing, modified transgluteal, lateral approach.

Indications: Primary hip osteoarthritis in physically active, working patients aged < 65 years (males) and < 60 years (females). Good bone quality.

[Silicate coating of cemented titanium-based shafts in hip prosthetics reduces high aseptic loosening].

Aim: For cemented hip prostheses, all requirements can be fulfilled by using forged Co/Cr/Mo stems. Co/Cr/Mo alloys, however, are contraindicated for allergy sufferers. For these patients, a cemented prosthesis made of titanium (alloy) would be indicated.

[Perineural cysts causing severe back pain and pathological fracture of the massa lateralis of the sacrum].

We report on the case of an 81-year-old woman who was hospitalised because of severe pain at the sacro-iliacal joint radiating into the left leg without any accompanying neurological defect. X-rays demonstrated a step in the left massa lateralis of the sacrum, thus CT scans and MRI were performed, and multiple perineural cysts (Tarlov's cysts) were found. The patient underwent microsurgical treatment by fenestration of the cyst wall and evacuation of the fluid content in order to avoid further expansion of the cysts.

[Intravertebral pressure during vertebroplasty - an in-vitro study].

Introduction: Extravasation of bone cement into the vertebral venous system during cement injection has been reported to be a major complication of percutaneous vertebroplasty. Therefore, high injection pressures during cement application into the fractured vertebral body are considered as one possible cause of cement leakage or extravasation. The aim of the current study was to measure the increase in intravertebral pressure caused by cement injection during vertebroplasty compared to the baseline venous pressure for the ascending lumbar vene.

[Optical coherence tomography (OCT) to evaluate cartilage tissue engineering].

Aim: The aim of this study was to investigate hyaline cartilage defects treated with cell-seeded artificial matrix systems (two different collagen type I gels) with the method of optical coherence tomography (OCT) and to correlate the results with conventional histological and immunocytochemical staining.

Method: Osteochondral blocks were harvested from 20 patients undergoing total knee replacement and trimmed to 2 x 2 cm. Under sterile conditions, chondral defects of 8 mm diameter were either filled with a collagen type I gel plug seeded with autologous chondrocytes (2 x 10 (5)/mL gel), or with a corresponding gel plug which was stabilised by a 20-fold compression.

[Fluoroscopic navigation versus conventional manual positioning of the femoral component for hip resurfacing: first experimental trial].

Background: The most essential improvement of modern hip resurfacing arthroplasty is the metal-on-metal bearing as well as the integration of a procedure for the exact and repeatable positioning of the femoral component through a specific mechanical alignment instrument. Nevertheless, the main reasons for early implant failure are mal-positioning of the femoral component and notching of the femoral neck during femoral head preparation.

Materials And Methods: In the context of an in vitro study, in each case six DUROM-Hip resurfacing prostheses were implanted in artificial femora with the prosthesis-specific mechanical alignment instrument, as well as under navigation control.

[Functionality and accuracy of a fluoroscopic navigation system in the placement of the femoral component for hip resurfacing - a cadaver study].

Introduction: Resurfacing arthroplasty represents an alternative method to total hip replacement especially for the young and active patient. The main reasons for early implant failure are mal-positioning of the femoral component and notching of the femoral neck during femoral head preparation.

Material And Methods: In the context of a cadaver study of formalin-fixed cadaveric full body specimens 6 DUROM -Hip-Resurfacing prosthesis have been implanted under navigation control.

In vitro interface and cement mantle analysis of different femur stem designs.

The aim of this study is to define stem design related factors causing both gaps in the metal-bone cement interface and cracks within the cement mantle. Six different stem designs (Exeter; Lubinus SP II; Ceraver Osteal; Mueller-straight stem; Centega; Spectron EF) (n=15 of each design) were cemented into artificial femur bones. Ten stems of each design were loaded, while five stems served as an unloaded control.

Assessment of leech therapy for knee osteoarthritis: a randomized study.

Background And Purpose: Symptomatic treatment of osteoarthritis of the knee with leeches is presently undergoing a renaissance. Previous studies have shown methodical weaknesses. In the present study patients were blinded regarding the treatment, and a control group was included to explore possible differences in various subjective clinical scores and intake of pain medication over time between leech therapy and placebo control.

[Mechanical bending strength of explanted ex vivo bone cements compared with in vitro samples].

Introduction: The mechanical properties of acrylic bone cements are an important factor in determining an efficient load transmission between prosthesis and bone to guarantee the long-term stability in cemented hip arthroplasty.

Material And Methods: Palacos and Refobacin Palacos specimens from 21 aseptically loosened femoral compoments of cemented hip arthroplasties manufactured by the first to third generation cementing technique have been mechanically tested in a standardised four-point bending test (ISO 5833). In vitro manufactured Palacos and Refobacin Palacos specimens served as a control group.

[Clinical results after three years use of matrix-associated ACT for the treatment of osteochondral defects of the knee].

Aim: The aim of this study was to examine the clinical results after the treatment of osteochondral defects of the knee with autologous bone grafting and matrix-supported autologous chondrocyte transplantation (ACT).

Method: In this study 13 patients with osteochondral defects of the knee (12 femoral, 1 tibial) with OCD ICRS grade IV or ICRS grade IV B were included. The osteochondral defects were reconstructed simultaneously with autologous monocortical cancellous bone cylinders or chips from cancellous bone and matrix-supported autologous chondrocyte transplantation (CaReS).

[Surface pretreatment of endoprostheses by silica/silane to optimise the hydrolytic stability between bone cement and metal. Total hip and knee arthroplasty].

Background: The aseptic loosening of cemented total hip and knee arthroplasties is still an unsolved problem. In this regard, the hydrolytic resistance in the metal-to-bone cement interface is of major importance.

Methods: Cemented pretreated femur stems and tibia components coated by means of a silica/silane interlayer system were dynamically loaded with the help of a hip and knee simulator similar to DIN ISO Norm.