Mid- to long-term periprosthetic bone density changes after cementless short stem hip arthroplasty in elderly: A clinical and radiological analysis.

Introduction: Short stem prostheses were originally designed for younger and more active patients. In recent years, they have been increasingly offered to older patients. This study evaluates the mid-to long-term survival of a short stem prosthesis and the changes in periprosthetic bone density following implantation of a cementless short hip stem in patients over 60 years of age.

Development and Finite Element (FE) analysis of a novel short hip stem concept.

Introduction: In order to improve the anchorage behavior of short hip stems, this development project aims at designing a short hip stem concept that preserves the femoral neck and minimizes interference with the physiological stress distribution of the femur. The new design will be evaluated according to ISO 7206-4 which is the standard for testing Implants for surgery.

Methods: Basic CAD models based on an established short stem prosthesis were created and evaluated using finite element analysis.

Acoustical determination of primary stability of femoral short stem during uncemented hip implantation.

Background: Preparing the medullary space of the femur aims to create an ideal form-fitting of cementless implants to provide sufficient initial stability, which is crucial for osseous integration, ensuring good long-term results. Hammering the implant into the proximal femur creates a press-fit anchoring of the endoprosthesis in the medullary space. Implanting the optimal size of the shaft for best fitting should avoid damage to the bone.

Retrospective clinical and X-ray-based outcome analysis of a short-stem hip arthroplasty taking into account the operative learning curve over 7 years in the 3-year control course.

Introduction: Self-monitoring is crucial to work progressively with a high-quality standard. A retrospective analysis is a valuable tool for studying the postoperative outcome of a prosthesis and for evaluating the learning process for the surgeon.

Materials And Methods: The learning process of one surgeon was analysed in 133 cases of hip arthroplasty.

Development and validation of an algorithm to determine the minimal factors needed for non-invasive measurement of the in vivo primary stability of cementless hip implants.

Aseptic loosening is a frequent cause for revision of endoprosthesis. X-ray examinations like Radio-Stereometry-Analysis (RSA) are among the most widely used in vivo methods for its detection. Nevertheless, this method is not used routinely because of bone marker and related radiation exposure.

Short Stem for Total Hip Arthroplasty (THA) - Overview, Patient Selection and Perspectives by Using the Metha Hip Stem System.

Short stem hip replacement has not only gained attention but also significance over the past decades. However, there still remains uncertainty regarding the correct indications for these stems. Even companies, producing implants, have varying recommendations that are more likely based on a well-meant advice than on statistically evaluated data.

How do the geometries of the broach handles relate to the distribution of force and moments in a femoral model?

The continuous improvement of minimally invasive hip endoprostheses surgery comes with a change in geometries of surgery instruments like the broach handles. Consequently, depending on the handles' curvature this results in a deviation between handle and femoral axis. Therefore, this study aimed to prove the influence of different handles' curvatures on the preparation of implant site and acting forces and moments in this process.

Comparison of Short Stems Versus Straight Hip Stems: A Biomechanical Analysis of the Primary Torsional Stability.

Cementless straight stems show very good survival rates. However, the more distal force application of straight stems may lead to release-related proximal stress-shielding. Nevertheless, this technical brief had the objective of conducting a biomechanical in vitro analysis comparing short stems with established straight stems with respect to their primary torsional stability.

How screw connections influence the primary stability of acetabular cups under consideration of different bone models.

Introduction: Good osteointegration of implants requires sufficient primary stability. Aim of this study was to examine the influence of screw fixation on the primary stability of press-fit cups.

Methods: Two press-fit acetabular cups were tested with regard to the influence and number of screws and their primary stability.

Outcome of short- to medium-term migration analysis of a cementless short stem total hip arthroplasty using EBRA-FCA: a radiological and clinical study.

Introduction: Stress shielding may lead to aseptic loosening which is a common reason for implant failure. An established method to identify implants with risk of implant failure caused by aseptic loosening is to measure early migration of the stem with the "Ein Bild Roentgen Analyse" femoral component analysis (EBRA-FCA). Therefore, the aim of this study was to measure the migration of a cementless short stem prosthesis via EBRA-FCA to predict the future performance.

In vitro examination of the primary stability of three press-fit acetabular cups under consideration of two different bearing couples.

Backround: For preclinical statements about the anchoring behavior of prostheses, the primary stability of the prosthesis is of special importance. It was the aim of this study to examine and compare the relevant relative micromotions of three different acetabulum prostheses by introducing three-dimensional torques.

Methods: The cups were implanted under standard conditions into an anatomical artificial bone model.

Age-related osseointegration of a short hip stem: a clinical and radiological 24 months follow-up.

Purpose: The purpose of this study was to examine potential differences between patients under and over 60 years who underwent a total short hip stem arthroplasty in a 24-month follow-up in a clinical setting.

Methods: Sixty seven patients were included in this prospective study and divided in two groups. In the younger cohort 39 patients ≤ 59 years and in the older cohort 28 patients ≥ 60 years were included.

Development of periprosthetic bone mass density around the cementless Metha® short hip stem during three year follow up-a prospective radiological and clinical study.

Purpose: The purpose of this study was to check the concept of the cementless Metha® short hip stem in order to find out whether proximal physiological load transfer can be achieved.

Methods: Fourty-three patients were included. Epidemiological factors were established.

Effect of bearing friction torques on the primary stability of press-fit acetabular cups: A novel in vitro method.

Aseptic loosening is the main reason for revision of total hip arthroplasty, and relative micromotions between cementless acetabular cups and bone play an important role regarding their comparatively high loosening rate. Therefore, the aim of the present study was to analyze the influence of resulting frictional torques on the primary stability of press-fit acetabular cups subjected to two different bearing partners. A cementless press-fit cup was implanted in bone-like foam.

Analysis of the elastic bending characteristics of cementless short hip stems considering the valgus alignment of the prosthetic stem.

Background: The resultant hip force causes a varus torque which must be compensated by a shear force couple depending on the stem alignment of the prosthesis. Since the prosthesis is substantially less flexible than the bone, the interior of the femur is stiffened over the entire prosthesis length. The present study thus aims at analyzing short-stem prostheses for its elastic bending characteristics, considering inappropriate valgus alignment of the prosthetic stem.

Influence of cerclages on primary stability of tumor megaprostheses subjected to distal femur defects.

Backround: Purpose of this experimental study was to investigate the influence of cerclages on the primary stability of the MUTARS system using distally fractured synthetic femora.

Methods: 4 MUTARS prostheses were implanted in synthetic femora respectively. Groups consisted of 4 intact bones, 4 fractured with cerclages and 4 fractured bones without cerclages.

Influences of fit and fill following hip arthroplasty using a cementless short-stem prosthesis.

Introduction: The purpose of this study consisted in examining the effects of fit and fill ratio of the Metha prosthesis (BBraun, Aesculap, Tuttlingen, Germany) on radiological and clinical outcomes at a follow-up of 1 year.

Methods: 40 patients were included. Fit and fill ratio measurements, radiological and clinical examinations were performed preoperatively and postoperatively.

Sports activities before and after medial unicompartmental knee arthroplasty using the new Heidelberg Sports Activity Score.

Purpose: The purpose of our study was to investigate the change of sports activities before and after medial unicompartmental knee arthroplasty (UKA) with the use of the Heidelberg Sports Activity Score (HAS).

Methods: The Heidelberg Sports Activity Score (HAS) as well as FFb-H-OA, Oxford-12-Score, Tegner, UCLA and ACS were carried out to assess sports activities in 157 patients with medial osteoarthritis of the knee joint before and after UKA. The newly developed HAS also records the important duration and the sporting activity.

Length of clinically proven cemented hip stems: state of the art or subject to improvement?

Purpose: The purpose of this study was to identify the shortest possible length of an established cemented hip stem in order to reduce stress shielding and optimise its bending behaviour.

Methods: Twenty-five prototypes from the same batch (five for each stem length) were included. Lengths resulted from the original length (100 %) and four distal shortenings to 94, 88, 83 and 78 % of original length.

Changes of periprosthetic bone density after a cementless short hip stem: a clinical and radiological analysis.

Purpose: The purpose of this study was to examine the concept of proximal load initiation of a total short-stemmed hip arthroplasty (Metha BBraun, Aesculap, Tuttlingen, Germany) on the basis of bone variations by means of osteodensitometric dual energy X-ray absorptiometry and radiologic measurements.

Methods: After power analysis 40 patients were included in this study. DXA examination, radiological and clinical follow-up was performed pre-operatively and postoperatively.

Gluteal silicone injections and total hip arthroplasty: a case report.

Introduction: Silicone injection is a common procedure in cosmetic surgery. Granuloma formation and migration are the most commonly observed complications.

Case Presentation: We report an unusual case of avascular necrosis of the hip in a 41-year-old woman from Thailand presenting with hip pain.

Fatigue fracture of a short stem hip replacement: a failure analysis with electron microscopy and review of the literature.

Four years after primary implantation of an ESKA Cut short-stemmed prosthesis, a 61-year-old patient suffered fracture of the implant. The combination of missing proximal support of the prosthesis as well as enormous strain on the distal third of the stem can be considered as main reason for the fatigue failure. The special design of the modular implant with a small diameter and a spongy metal surface can be regarded as a contributing factor.