Small and similar amounts of micromotion in an anatomical stem and a customized cementless femoral stem in regular-shaped femurs. A 5-year follow-up randomized RSA study.

Background And Purpose: High primary stability is important for long-term survival of uncemented femoral stems. Different stem designs are currently in use. The ABG-I is a well-documented anatomical stem with a press-fit design.

Periprosthetic bone loss after insertion of an uncemented, customized femoral stem and an uncemented anatomical stem. A randomized DXA study with 5-year follow-up.

Background And Purpose: Customized femoral stems are designed to have a perfect fit and fill in the femur in order to achieve physiological load transfer and minimize stress shielding. Dual-energy X-ray absorptiometry (DXA) is regarded as an accurate method for detection of small alterations in bone mineral density (BMD) around hip prostheses. We present medium-term DXA results from a randomized study comparing a customized and an anatomical femoral stem.

Transposition of the apophysis of the greater trochanter for reconstruction of the femoral head after septic hip arthritis in children.

Background And Purpose: Total necrosis of the femoral head after infection in children during their first months of life gives a dislocated hip with severe leg shortening. A new femoral head can be achieved with subtrochanteric osteotomy and transposition of the apophysis of the greater trochanter into the acetabulum. Previous reports have dealt with short-term results (up to 12 years).

Uncemented custom femoral components in hip arthroplasty. A prospective clinical study of 191 hips followed for at least 7 years.

Background And Purpose: We have developed an individually designed, uncemented femoral component for achievement of improved strain distribution and fixation to the bone, to make uncemented stems more applicable in femurs of abnormal size and shape, and to improve the joint mechanics. Here we describe the design of the implant and present the results of a prospective clinical study with at least 7 years of follow-up.

Patients And Methods: The prostheses are produced by CAD-CAM technique.

Customised femoral stems in osteopetrosis and the development of a guiding system for the preparation of an intramedullary cavity: a report of two cases.

Traditional techniques for the insertion of femoral stems in arthroplasty of the hip in osteopetrosis carry a considerable risk of penetration of the femoral cortex and intra-operative fractures, due to obliteration of the intramedullary cavity and greatly increased stiffness and brittleness of the bone. In order to reduce the risk of such complications we manufactured a customised stem and a computer-based guiding device for the preparation of a cavity within the proximal femur. This system was used successfully in three hips in two patients.

Unilateral vs. bilateral total hip arthroplasty - the influence of medial femoral head offset and effects on strength and aerobic endurance capacity.

The purpose of the present study was to determine whether unilaterally operated total hip arthroplasty (THA) patients were superior to bilaterally operated THA patients with respect to aerobic endurance capacity, muscle strength and gait patterns 3-5 years after surgery, and to what extent medial femoral head offset (FO) influenced hip abductor strength. 10 unilaterally operated THA patients with normal FO (UNO), 10 bilaterally operated THA patients with normal FO (BNO) and 10 bilaterally operated THA patients with abnormal offset (BDO) participated in the study. Improved muscle strength in the healthy leg of the UNO did not result in differences compared to the BNO and the BDO in work efficiency, gait patterns or maximal oxygen consumption (VO2max ) A reduced FO in the BDO did not result in lower hip abduction strength compared to the BNO.

A prospective randomised radiostereometric analysis trial of SmartSet HV and Palacos R bone cements in primary total hip arthroplasty.

Background: Introduction of new bone cements into clinical practice should include radiostereometric studies.

Materials And Methods: A prospective randomised radiostereometric study was performed, comparing SmartSet HV and Palacos R acrylic bone cements (without antibiotics) using third-generation cementing techniques in primary total hip arthroplasty. Thirty-five patients (36 hips) undergoing Charnley total hip arthroplasty were randomised to receive either of the two cements and were followed with repeated clinical, radiographic and radiostereometric examinations over 24 months.

Early postoperative maximal strength training improves work efficiency 6-12 months after osteoarthritis-induced total hip arthroplasty in patients younger than 60 years.

Objective: To assess physical outcome of early maximal strength training after total hip arthroplasty.

Design: Six- and 12-mo follow-up of 24 (22) total hip arthroplasty patients randomly assigned to 4 wks of maximal strength training and conventional rehabilitation and to conventional rehabilitation only was conducted. After the intervention period, all patients attended conventional rehabilitation.

Early maximal strength training is an efficient treatment for patients operated with total hip arthroplasty.

Unlabelled: Husby VS, Helgerud J, Bjørgen S, Husby OS, Benum P, Hoff J. Early maximal strength training is an efficient treatment for patients operated with total hip arthroplasty.

Objective: To compare muscle strength, work efficiency, gait patterns, and quality of life in patients undergoing total hip arthroplasty (THA) randomly assigned to either maximal strength training or a conventional rehabilitation program.

Polyethylene acetabular wear in hip prostheses: computer-simulated quantification of error caused by changes in pelvic orientation and direction of wear.

Background And Purpose: Polyethylene is commonly employed for bearings in acetabular cups used in hip replacements. Assessment of in vivo wear is important for evaluation and monitoring of wear in individual patients, as well as in different implant designs. Polyethylene wear is quantified by comparisons of radiographic measurements made on sequential pelvic radiographs.

A clinical and radiographic 13-year follow-up study of 138 Charnley hip arthroplasties in patients 50-70 years old: comparison of university hospital data and registry data.

Background And Purpose: Arthroplasty registers provide rates of implant survival in large populations based on implant revision. In an unrevised prosthesis population, some patients may have implants with clinically poor outcome or radiographic failure. We therefore evaluated medium-term clinical and radiographic results in patients with charnley hip arthroplasties and compared our results with data from the Norwegian Arthroplasty Register (NAR).

The rotation ratios method: a method to describe altered pelvic orientation in sequential radiographs.

Background: A method to describe pelvic rotations between pairs of standard sequential pelvic anteroposterior radiographs based on a pelvic phantom is described in a former study.

Purpose: To expand this method into clinical use based on clinical data.

Material And Methods: Teardrop distances were measured on 262 pelvic radiographs from 46 patients in a clinical material using a computer program designed to perform measurements on digital radiographs.

Validation of the rotation ratios method.

Background: The rotation ratios method describes rotations between pairs of sequential pelvic radiographs. The method seems promising but has not been validated.

Purpose: To validate the accuracy of the rotation ratios method.

Pelvic rotations: a pelvic phantom study.

Background: Radiographic measurements made on standard pelvic radiographs are commonly used in studying conditions related to the hip joints. Effects caused by variations in pelvic orientation may be a source of error in comparing measurements between sequential radiographs.

Purpose: To define and characterize parameters able to measure rotational differences separately around two axes and altered radiographic focusing along two axes when sequential standard anteroposterior (AP) pelvic radiographs are compared.

Improved comfort and function of arm prosthesis after implantation of a Humerus-T-Prosthesis in trans-humeral amputees.

The use of arm prosthesis in trans-humeral amputees is limited; due to the cone form of the amputation stump. A Humerus-T-Prosthesis was implanted in three patients to create artificial humerus condyles. Two of the patients were successfully rehabilitated with the application of a new type trans-humeral arm prosthesis.

Factors affecting stiffness properties in impacted morsellized bone used in revision hip surgery: an experimental in vitro study.

When revising loosened joint prosthesis, impacted morsellized bone is frequently used as organic scaffolding. We studied the relative influence that different bone particle size, impaction energy, and liquid content had on impacted bone stiffness. Bovine bone was morsellized in a bone mill by three grinding drums to produce bone with different chip size distribution.

Influence of water and fat content on compressive stiffness properties of impacted morsellized bone: an experimental ex vivo study on bone pellets.

Background: The initial stability of an exchanged hip arthroplasty is crucial for the survival of the revised joint. Several factors can affect the outcome. The amount of liquid in morsellized bone has a major influence on the constrained stiffness properties of impacted bone applied in revision joint surgery.

Cortical allograft as a vehicle for antibiotic delivery.

Background: Infection can be a devastating complication after implantation of a cortical bone allograft. The allograft could act as a vehicle for local antibiotic prophylaxis.

Material And Methods: We studied the release of antibiotics in vitro from cortical bone allografts impregnated with antibiotics for different periods of time.

Viscoelastic modelling of impacted morsellised bone accurately describes unloading behaviour: an experimental study of stiffness moduli and recoil properties.

Morsellised bone impaction grafting is commonly used for revision arthroplasty surgery. Several reports have described the mechanical behaviour of this bone material during impaction and loading. In this study we observed the unloading progress.

External fixation versus locked intramedullary nailing in tibial shaft fractures: a prospective, randomised study of 78 patients.

Introduction: We performed a prospective, randomised study to compare the Ex-fi-re external fixator (EF) with locked intramedullary (IM) nailing in tibial fractures. Only fractures without soft-tissue problems of importance were included.

Materials And Methods: Ex-fi-re is a unilateral, dynamic axial fixator with fracture reduction capabilities.

Impacted bone stiffness measured during construction of morsellised bone samples.

Impacted morsellised bone is widely used for filling bone deficiencies during revision of total hip arthroplasties. However, the physical properties and mechanical behaviour of this bone material are still not well understood. In this study we recorded the increase of stiffness in pellets of morsellised bone during their construction.

High local concentrations without systemic adverse effects after impaction of netilmicin-impregnated bone.

Background: When cancellous bone is impregnated with antibiotics the subsequent release of antibiotics from the bone shows a high early release. Hence, impaction of large amounts of netilmicin-impregnated bone may cause toxic netilmicin values in serum.

Patients And Methods: We studied kidney and otovestibular function after impacting 50 g of netilmicin-impregnated cancellous bone during revision hip or knee arthroplasty in 20 patients.

Mechanical stability of custom and anatomical femoral stems: an experimental study in human femora.

In this study we have compared the mechanical stability of custom (n=8) and anatomical (n=8) uncemented femoral components, following insertion into human cadaveric femurs, during simulated single leg stance and stair climbing. In the custom group two specimens were excluded from the study due to detachment of the greater trochanter during cyclical loading. As a consequence of their mechanical behaviour both types of stems could be divided into subgroups of "unstable" and "stable" implants.

Release of netilmicin and vancomycin from cancellous bone.

First, we studied the effect of the following variables used for netilmicin- and vancomycin-impregnation of cancellous bone: a) antibiotic concentration of the impregnation fluid, b) time used for impregnation, c) pH of the impregnation fluid, d) the degree of bone morselizing and e) antibiotic combination. An increase in the antibiotic concentration of the impregnation fluid increased the amount of antibiotics released from bone. In addition, the amount of vancomycin eluted was also dependent on the time used for impregnation.