Extremely Low Transfusion Rates: Contemporary Primary Total Hip and Knee Arthroplasties.

Background: Considerable blood loss which requires transfusion is frequently reported after total hip and knee arthroplasties (THA and TKA). The purpose of this study is to review the transfusion rates in contemporary THA and TKA with optimized perioperative protocols including minimized surgical trauma and optimal perioperative patient care.

Methods: This retrospective study included 1442 consecutive patients receiving either a primary THA or a TKA from the same high-volume surgeon between January 2008 and December 2015.

Influence of polyethylene constraint on tibial component fixation in total knee arthroplasty: follow-up report after 5 years.

The influence of articulating surface design of AMK total knee prosthesis (DePuy, Johnson & Johnson) on migration and radiographic outcome at 5 years was evaluated. The knees were randomly allocated to receive a flat or a concave insert with retention of the posterior cruciate ligament when preoperative deformity was less severe and either a concave or a posterior-stabilized insert with resection of the posterior cruciate ligament when deformity was more pronounced. In 64 knees, migration was measured with radiostereometry.

Posterior stabilized component increased femoral bone loss after total knee replacement. 5-year follow-up of 47 knees using dual energy X-ray absorptiometry.

After total knee replacement (TKR) bone mineral density (BMD) commonly decreases behind the anterior flange of the femoral component, which may increase the risk for supracondylar fracture. Our aim was to evaluate if changes in femoral design and joint area constraint had any effect on the postoperative bone remodeling in the distal femur. We used dual-energy X-ray absorptiometry in 47 knees up to 5 years after operation with the AMK (DePuy, Johnson and Johnson Leeds, UK) TKR.

Stepwise introduction of a bone-conserving osseointegrated hip arthroplasty using RSA and a randomized study: II. Clinical proof of concept--40 patients followed for 2 years.

Background: We have developed a bone-conserving commercially pure titanium hip replacement system using osseointegration principles: a metaphyseal loading proximal femoral component affixing into the retained neck and metaphysis only, leaving the femoral canal untouched. The acetabular cup closely fits a dual-geometry cavity, avoiding stress protection at the dome.

Patients And Methods: After extensive laboratory and clinical pilot trial investigations, the surface-engineered implants were submitted to a prospective randomized controlled clinical trial involving 40 patients (40 hips), in which they were compared to the cemented Spectron femoral component and cementless Trilogy cup as control implant.

Stepwise introduction of a bone-conserving osseointegrated hip arthroplasty using RSA and a randomized study: I. Preliminary investigations--52 patients followed for 3 years.

Background: We developed a total hip system using osseointegration guidelines, a metaphyseal-loading proximal femoral replacement in the retained neck and a dual-geometry titanium shell in the acetabulum.

Patients And Methods: A randomized controlled clinical trial was undertaken in 52 patients (53 hips), using the cemented Spectron stem and cementless Harris-Galante II cup as control implants (24 patients in experimental group, 29 control patients). Clinical measures of Harris Hip Score (HHS), pain score and radiostereometric analysis (RSA) at regular intervals for up to three years were used to monitor progress.

Aseptic loosening, not only a question of wear: a review of different theories.

Today, aseptic loosening is the most common cause of revision of major arthroplasties. Aseptic loosening accounts for more than two-thirds of hip revisions and almost one-half of knee revisions in Sweden. Several theories on the cause of aseptic loosening have been proposed.

Minimally invasive surgery vs conventional exposure using the Miller-Galante unicompartmental knee arthroplasty: a randomized radiostereometric study.

Forty-one patients were randomized to a cemented Miller-Galante unicompartmental (Zimmer, Warsaw, Ind) knee arthroplasty inserted with either minimally invasive surgery or with a standard exposure. Clinical data and conventional radiographs were recorded and patients were followed with radiostereometric analysis to measure migration rate of the tibial component. The rehabilitation of patients operated through a small incision was faster, and there was a significant difference in days of hospitalization (P = .

Improved tibial cutting accuracy in knee arthroplasty.

Initial stability and development of long-term fixation for cementless tibial components at the knee both depend on the accuracy of fit between implanted components and prepared bone surfaces. Tibial surfaces prepared for total knee replacement with conventional saw-blades and guides were shown by Toksvig-Larsen to vary by over 2 mm, from a flat surface at the point of maximum variation, and all points varied with a standard deviation of up to 0.4 mm.

Does sodium fluoride in bone cement affect implant fixation. Part II: evaluation of the effect of sodium fluoride additions to acrylic bone cement and the fixation of titanium implants in ovariectomized rabbits.

Bone integration of threaded implants made of cured polymethylmethacrylate containing sodium fluoride or commercially pure (c.p.) titanium were studied in normal and estrogen deficient New Zealand white rabbits.

Does sodium fluoride in bone cement affect implant fixation? Part I: bone tissue response, implant fixation and histology in nine rabbits.

The addition of sodium fluoride to poly (methyl-methacrylate) (PMMA) bone cement may theoretically improve the fixation of joint replacement. This hypothesis was tested in an animal model using nine mature healthy lop-eared rabbits. A femoral prosthesis was inserted in both knees to resurface the patellofemoral articulation.

Long-term results of a cementless knee prosthesis with a metal-backed patellar component: clinical and radiological follow-up with histology from retrieved components.

Aseptic loosening of cemented knee arthroplasties has encouraged development of uncemented fixation. The Miller-Galante I (MG I) prosthesis was designed to achieve permanent stability through ingrowth into a titanium fiber mesh. Thirty-five knees in 30 patients with MG I knee replacements have been followed clinically and radiologically with a mean follow-up of 12 years.

A novel liner locking mechanism enhances retention stability.

Acetabular liner retention of a novel design of liner locking was evaluated in static and cyclic endurance modes. The locking mechanism combines geometric form and accurate machining to give high conformity to the acetabular shell and minimise relative motion against the metal shell, minimising debris generation and escape or ingress. Using amended test liners with integral coupling, mean static pullout strength was determined to be 399+/-53 N and lever-out strength 28.

Kinematics of three variations of the Freeman-Samuelson total knee prosthesis.

The effect of changes in the articulating surfaces on the kinematics of the Freeman-Samuelson total knee replacement was evaluated. Twenty-two patients (22 knees) (median age, 69 years) were randomized to a standard design with a fixed polyethylene bearing, a design with a mobile bearing, or a new design with a spherical medial femoral condyle with a fixed bearing. The patients were studied with radiostereometry and film-exchangers at 0 degrees nonweightbearing and during active weightbearing extension from 45 degrees to 15 degrees.

Effect of submicron polyethylene particles on an osseointegrated implant: an experimental study with a rabbit patello-femoral prosthesis.

In a rabbit model of a weight bearing, articulating prosthetic joint we repeatedly injected submicron particles of Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) produced in a hip simulator. The contralateral knee with the same prosthesis was injected with carrier (NaCl) without UHMWPE. Histomorphometrical studies on undecalcified cut and ground sections at 26 and 42 weeks involved quantifications of the entire bone to metal contact and the bone area around each implant.