Aseptic loosening is the main reason for total knee arthroplasty (TKA) failure, responsible for more than 25% of the revision procedures, with most of the problems occurring with the tibial component. While early loosening can be attributed to failure of primary fixation, late implant loosening is associated with loss of fixation secondary to bone resorption due to altered physiological load transfer to the tibial bone. Several attempts have been made to investigate these changes in bone load transfer in biomechanical simulations and bone remodeling analyses, which can be useful to provide information on the effect of patient, surgery, or design-related factors. On the other hand, these factors have also been investigated in clinical studies of radiographic changes of bone density following TKA. In this study we made an overview of the knowledge obtained from these clinical studies, which can be used to inform clinical decision making and implant design choices. A literature search was performed to identify clinical follow-up studies that monitored peri-prosthetic bone changes following TKA. Within these studies, effects of the following parameters on bone density changes were investigated: post-operative time, region of interest, alignment, body weight, systemic osteoporosis, implant design and cementation. Moreover, we investigated the effect of bone density loss on implant survival. Results A total of 19 studies was included in this overview, with a number of included patients ranging from 12 to 7,760. Most studies used DEXA (n=16), while a few studies performed analyses on calibrated digital radiographs (n=2), or computed tomography (n=1). Postoperative follow-up varied from 9 months to 10 years. Studies consistently report the largest bone density reduction within the first postoperative year. Bone loss is mainly seen in the medial region. This has been attributed to the change in alignment following surgery, during which often the pre-operative varus knee is corrected to a more physiological alignment, resulting in a load shift towards the lateral compartment. Measurements in unoperated contralateral legs were performed in 3 cases, and two studies performed standardized DEXA measurements to provide information on systemic osteoporosis. While on the short term no changes were observed, significant negative correlations have been found between severity of osteoporosis and peri-prosthetic bone density. No clear effects of bodyweight and cementation on bone loss have been identified. Although some studies do find differences between implant types, the variation in the data makes it difficult to draw general conclusions from these findings. Several studies reported no effect of bone loss on implant migration. In another study, a medial collapse was associated with a medial increase in density, suggesting that altered loading and increased stresses are responsible for both bone formation and the overload leading to collapse.Introduction
Methods
Femoral stem design affects periprosthetic bone mineral density (BMD), which may impact long term survival of cementless implants in total hip arthroplasty (THA). The aim of this study was to examine proximal femoral BMD in three morphologically different uncemented femoral stems designs to investigate whether one particular design resulted in improved preservation of BMDMethods: 119 patients were randomised to receive either a proximally coated dual taper wedge stem, a proximally coated anatomic stem or a fully coated collarless triple tapered stem. All surgeries were performed via the posterior approach with mobilization on the day of surgery.
Disorders of bone integrity carry a high global disease burden, frequently requiring intervention, but there is a paucity of methods capable of noninvasive real-time assessment. Here we show that miniaturized handheld near-infrared spectroscopy (NIRS) scans, operated via a smartphone, can assess structural human bone properties in under three seconds. A hand-held NIR spectrometer was used to scan bone samples from 20 patients and predict: bone volume fraction (BV/TV); and trabecular (Tb) and cortical (Ct) thickness (Th), porosity (Po), and spacing (Sp).Aims
Methods
Managing severe acetabular bone defects during primary and revision total hip arthroplasty is a challenging problem. Standard treatment options for this cases is using of acetabular reconstruction type-Burch-Schneider rings. Unfortunately, the possibility of osseointegration of these implants with surrounding bone has always remained a contentious issue. The emergence in recent years of new designs of trabecular titanium, representing a symbiosis of acetabular reconstructive plates and modular cup helped to solve this problem on a completely new level. The aim of this prospective study is to evaluate the short and mid-term clinical and radiographic outcomes of different types of acetabular revision cups - old and new design. From 2006 to 2015, we performed 48 acetabular reconstruction with reconstruction rings CONTUR Smith and Nephew(group 1) and 34 operations with Delta TT Lima Revision system (group 2). The mean age of patients was 59.2 years (range 30–79). Indications for operations included fractures in acetabular region (10 pat – 12,2 %), acetabular nonunions with bone defects (14 pat – 17,1%), aseptic loosening with multiple dislocation of the primary implants in 38 cases (46,3%) and second stage of infection treatment in 20 cases (24.4%). Clinical and functional outcomes were evaluated by Harris Hip Score (HHS). Bone density in Charnley's zones was measured by
Purpose. The purpose of this study was to evaluate periprosthetic bone mineral density (BMD) changes around a cementless short tapered-wedge stem and determine correlations between BMD changes and various clinical factors, including daily activity, after total hip arthroplasty (THA) with a short tapered-wedge stem. Methods. The study included 65 patients (65 joints) who underwent THA with a TriLock stem. At baseline, and 6, 12, and 24 months postoperatively, BMDs of the seven Gruen zones were evaluated using
Introduction. Resorptive bone remodeling secondary to stress shielding has been a concern associated with cementless total hip arthroplasty (THA). At present, various types of cementless implants are commercially available. The difference in femoral stem design may affect the degree of postoperative stress shielding. In the present study, we aimed to compare the difference in bone mineral density (BMD) change postoperatively in femurs after the use of 1 of the 3 types of cementless stems. Methods. Ninety hips of 90 patients who underwent primary cementless THA for the treatment of osteoarthritis were included in this study. A fit-and-fill type stem was used for 28 hips, a tapered-rectangular Zweymüller type stem was used for 32 hips, and a tapered-wedge type stem was used for 30 hips. The male/female ratio of the patients was 7/21 in the fit-and-fill type stem group, 6/26 in the tapered-rectangular Zweymüller type stem group, and 6/24 in the tapered-wedge type stem group. The mean age at surgery was 59.9 (39–80) in the fit-and-fill type stem group, 61.7 (48–84) in the tapered-rectangular Zweymüller type stem group and 59.6 (33–89) in the tapered-wedge type stem group. To assess BMD change after THA, we obtained
INTRODUCTION. Total hip arthroplasty (THA) is a very successful orthopaedic treatment with 15 years implant survival reaching 95%, but decreasing age and increasing life expectancy of THA patients ask for much longer lasting solutions. Shorter and more flexible cementless stems are of high interest as these allow to maintain maximum bone stock and reduce adverse long-term bone remodeling.1 However, decreasing stem length and reducing implant stiffness might compromise the initial stability by excessively increasing interfacial stresses. In general, a good balance between implant stability and reduced stress shielding must be provided to obtain durable THA reconstruction.2. This finite element (FE) study aimed to evaluate primary stability and bone remodeling of a new design of short hip implant with solid and U-shaped cross-section. MATERIALS AND METHODS. The long tapered Quadra-H stem and the short SMS implants (Medacta International, Castel San Pietro, Switzerland) were compared in this study (Figure 1). A FE model of a femur was based on calibrated CT data of an 81 year-old male (osteopenic bone quality). Both titanium alloy implants were assigned an elastic modulus of 105 GPa and the Poisson's ratios were set to 0.3. Initial stability simulations included the hip joint force and all muscle loads during a full cycle of normal walking as calculated in AnyBody software (Anybody Technology AS, Denmark), whereas the remodeling simulation used the peak loads from normal walking and stair climbing activities. Initial stability results are presented as micromotions on the implant surface with a threshold of 40 µm.3 Bone remodeling outcomes are represented in a form of simulated
Modern prosthetic stem construction strives to achieve the attractive goals of stress shielding prevention and optimal osteointegration. PhysioLogic stem is a new generation composite isoelastic femoral stem consisting of titanium core sheathed in implantable PEEK polymer and coated with titanium layer. This construction combines the benefits of both stress shielding prevention, due to its elasticity under bending load corresponding closely to that of natural bone, and rapid osteointegration, due to the stem's titanium coating. The aim of this study is long-term clinical progress evaluation and retrospective analysis in patients undergoing primary PhysioLogic stem implantation at our institution. From 1998 to 2003, we performed 51 primary total hip arthroplasty (THA) operations with implantation of PhysioLogic Stem at our institution. Indications for THA included osteoarthritis (21), hip dysplasia (14), rheumatoid arthritis (10), and femoral neck nonunion (6). In all patients we used totally uncemented system — PhysioLogic Stem and monoblock cup with different types of bearing surface articulation (40 metal/polyethylene, 3 ceramic/polyethylene, and 8 metal/metal). In all cases head size was 28mm. Two patients died in the early post-op period at day 1 and day 9 from disseminated intravascular coagulation and pulmonary embolism, respectively, and were excluded from subsequent analysis. Analyzed patients included 20 women and 29 men; median age 45, range 21–69. Post-operatively, the patients were evaluated at 3 and 6 months, 1 year, and yearly thereafter. Median follow-up period was 14 years, range 11 to 16 years. Clinical and functional outcomes were evaluated by Harris Hip Score. Bone density in Gruen's and Charnley's zones was measured by
An osteoporosis screening service for patients presenting to the fracture clinic in Derriford Hospital Plymouth was established in February 2009. We report on the findings of the first year of patients referred for
INTRODUCTION. Implantation of total hip arthroplasty (THA) components caused a significant alteration in stress environment. Several studies have reported that bone mineral density (BMD) decreases after THA, especially in the proximal femur. This phenomenon is explained as an adaptive remodeling response of bone tissue to a significant alteration in its stress environment. SL-PLUS MIA stem (Smith & Nephew Orthopaedics AG) is a modified implant of Zweymuller type SL-PLUS standard stem (Smith & Nephew Orthopaedics AG). The major change is an omission of the trochanteric wing, which enables a bone-sparing and may lead to changes of femoral stress distribution and rotational stability. The change of stress distribution in the femur could affect BMD after THA. In the present study, we constructed finite element (FE) models of femurs and stems before and at 1week after THA and analyzed equivalent stresses in the femur. In addition, we measured BMD in the femur by
In cases of poor bone quality intraoperative torque measurement might be an alternative to preoperative
Purpose of study:. The purpose of the study is to evaluate the changes in peri-prosthetic bone mineral density following cemented and cementless total hip arthroplasty over a follow up period of 1 year. Description of methods:. Ethics approval was sought and granted by the South African Medical Association Research Ethics Committee (SAMAREC). Patient consent for participation was obtained. Recruitment of the cohort took place over 2 years. Patients received an uncemented (Synergy) or cemented (Spectron) prosthesis as clinically appropriate. Functional status according to the University of California Los Angeles activity scale (UCLA scale) and bone mineral density as measured by
Six week old male Sprague-Dawley rats were administered intravenous clozapine, quetiapine, haloperidol or vehicle once daily for a period of 42 days with access to only high fat diet and their weight was monitored regularly. At the end of the study the rats were killed and the tibiae excised and bone mineral density (BMD) measured with
INTRODUCTION. Trabecular Titanium™ is an innovative material characterised by an high open porosity and composed by multi-planar regular hexagonal cells. It is not a traditional coating and its tri-dimensional structure has been studied to optimise osteointegration. Furthermore, it has excellent mechanical properties, as a very high tensile and fatigue resistance and an elastic module very similar to the that of the trabecular bone. The aim of this study is to evaluate the osteointegration and bone remodelling measuring the longitudinal pattern of change in BMD around a cementless acetabular cup made from Trabecular Titanium™ (Delta TT cup, Lima Corporate, Italy) in primary total hip arthroplasty (THA). METHODS.
Introduction. Revision hip arthroplasty is a technically challenging operation as proximal bony deficits preclude the use of standard implants. Longer distally fixing stems are therefore required to achieve primary stability. Aims. This work aims to compare the primary stability and biomechanical properties of a new design of tapered fluted modular femoral stem (Redapt®, Smith & Nephew) to that of a conical fluted stem (Restoration®, Stryker). It is hypothesized that the taper will provide improved rotational stability under cyclical loading. Materials & Methods. 7 Pairs of cadaveric femora were obtained according to strict inclusion/exclusion criteria. Each underwent
Trabecular TitaniumTM is a tri-dimensional material composed by multi-planar regular hexagonal cells and characterised by a highly open porosity that has been studied to optimise bone osteointegration. The aim of this study is to evaluate bone remodelling measuring BMD changes around an acetabular cup made from Trabecular TitaniumTM in primary total hip arthroplasty (THA). Between February 2009 and December 2010, 89 patients (91 hip) underwent primary THA with a modular acetabular cup in Trabecular TitaniumTM (DELTA-TT cup, Limacorporate, Villanova di San Daniele, Italy). The average age was 63.5± 9.4 years, the average height and weight were 75.9± 12.9 kg and 168.8± 8.9 cm, respectively (av. BMI 26.8± 4.2). There were 46 (51.7%) males and 43 (48.3%) females affected by primary coxarthrosis in 80 (87.9%) cases, avascular necrosis in 5 (5.5%), posttraumatic coxarthrosis in 3 (3.3%), dysplasia in 2 (2.2) and oligoarthritis in 1 (1.1%) case. The study includes the clinical evaluation with Harris Hip Score (HHS) and SF-36, radiographic evaluation and
Purpose. Alpine skiing is associated with large skeletal loads with distinct patterns of loading rate and direction, and alpine skiers were previously found to have a robust bone structure compared to normally active controls. However, it is not known whether the mechanical stimuli experienced by skiers are also associated with enhanced bone microarchitecture and strength. Thus, the purpose of this study was to use high-resolution peripheral quantitative computed tomography (HR-pQCT) to compare bone macro- and microarchitecture and bone strength between elite alpine skiers and normally active controls. Method. Participants included 7 female and 12 male members of the Canadian Alpine Ski Team, and 10 female and 16 male normally active control subjects. A whole body