Advances in the performance and longevity of total joint arthroplasty (TJA) have been enabled by related progress in implant materials, device designs, and surgical techniques. Successful TJA also depends upon adequate
There is an established link between
In cases of poor
As a part of the European Union BIOMED I study “Assessment of
Purpose. Stress fractures (SFs) are highly prevalent in female athletes, especially runners (1337%), and result in pain and lost training time. There are numerous risk factors for SFs in athletes; however, the role of
Introduction. Atypical femoral fracture focused on relation of bisphosphonate use, frequently. However, the mechanism of atypical femoral fracture was not yet clarified. Atypical femoral fractures have been kept femoral shaft cortical thickness and BMD, practically. We hypothesized that atypical femoral fractures were associated with impaired
Introduction. Initial large-scale clinical studies of porous tantalum implants have been generally promising with well-fixed implants and few cases of loosening [1–3]. An initial retrieval study suggests increased bone ingrowth in a modular tibial tray design compared to the monoblock design [4]. Since micromotion at the bone-implant interface is known to influence bone ingrowth [5], the goal of this study was to determine the effect of implant design,
Objective: To examine the relationship between three measurements of
Stem malalignment in total hip arthroplasty (THA) has been associated with poor long-term outcomes and increased complications (e.g. periprosthetic femoral fractures). Our understanding of the biomechanical impact of stem alignment in cemented and uncemented THA is still limited. This study aimed to investigate the effect of stem fixation method, stem positioning, and compromised bone stock in THA. Validated FE models of cemented (C-stem – stainless steel) and uncemented (Corail – titanium) THA were developed to match corresponding experimental model datasets; concordance correlation agreement of 0.78 & 0.88 for cemented & uncemented respectively. Comparison of the aforementioned stems was carried out reflecting decisions made in the current clinical practice. FE models of the implant positioned in varus, valgus, and neutral alignment were then developed and altered to represent five different bone defects according to the Paprosky classification (Type I – Type IIIb). Strain was measured on the femur at 0mm (B1), 40mm (B2), and 80mm (B3) from the lesser trochanter.Abstract
Objectives
Methods
Aims. Anchorage of pedicle screw rod instrumentation in the elderly spine with poor
Introduction: The ‘gold standard’ currently used to assess
Cemented total hip replacements (THR) are widely used and are still recognized as the gold standard by which all other methods of hip replacements are compared. [. 1. ]. Long-term results of cemented total hip replacements show that the revision rate due to aseptic loosening could be as high as 75.4% [. 2. ]. Moreover, high stresses developed in the cement mantle of reconstructed hips can lead to premature failure of the constructs [. 3. ]. Surgical fixation techniques vary considerably [. 4. ]. The aim of this study was to investigate the performances of different surgical fixation techniques of hip implants for patients with different body mass indices, bone morphology and
Aims. The Exeter short stem was designed for patients with Dorr type A femora and short-term results are promising. The aim of this study was to evaluate the minimum five-year stem migration pattern of Exeter short stems in comparison with Exeter standard stems. Methods. In this case-control study, 25 patients (22 female) at mean age of 78 years (70 to 89) received cemented Exeter short stem (case group). Cases were selected based on Dorr type A femora and matched first by Dorr type A and then age to a control cohort of 21 patients (11 female) at mean age of 74 years (70 to 89) who received with cemented Exeter standard stems (control group). Preoperatively, all patients had primary hip osteoarthritis and no osteoporosis as confirmed by dual X-ray absorptiometry scanning. Patients were followed with radiostereometry for evaluation of stem migration (primary endpoint), evaluation of cement quality, and Oxford Hip Score. Measurements were taken preoperatively, and at three, 12, and 24 months and a minimum five-year follow-up. Results. At three months, subsidence of the short stem -0.87 mm (95% confidence interval (CI) -1.07 to -0.67) was lower compared to the standard stem -1.59 mm (95% CI -1.82 to -1.36; p < 0.001). Both stems continued a similar pattern of subsidence until five-year follow-up. At five-year follow-up, the short stem had subsided mean -1.67 mm (95% CI -1.98 to -1.36) compared to mean -2.67 mm (95% CI -3.03 to -2.32) for the standard stem (p < 0.001). Subsidence was not influenced by preoperative
The
Dorr bone type is both a qualitative and quantitative classification. Qualitatively on x-rays the cortical thickness determines the ABC type. The cortical thickness is best judged on a lateral x-ray and the focus is on the posterior cortex. In Type A bone it is a thick convex structure (posterior fin of bone) that can force the tip of the tapered implant anteriorly – which then displaces the femoral head posteriorly into relative retroversion. Fractures in DAA hips have had increased fractures in Type A bone because of the metaphyseal-diaphyseal mismatch (metaphysis is bigger than diaphysis in relation to stem size). Quantitatively, Type B bone has osteoclastic erosion of the posterior fin which proceeds from proximal to distal and is characterised by flattening of the fin, and erosive cysts in it from osteoclasts. A tapered stem works well in this bone type, and the bone cells respond positively. Type C bone has loss of the entire posterior fin (stove pipe bone), and the osteoblast function at a low level with dominance of osteoclasts. Type C is also progressive and is worse when both the lateral and AP views show a stove pipe shape. If just the lateral x-ray has thin cortices, and the AP has a tapered thickness of the cortex a non-cemented stem will work, but there is a higher risk for fracture because of weak bone. At surgery Type C bone has “mushy” cancellous bone compared to the hard structure of type A. Tapered stems have high risk for loosening because the diaphysis is bigger than the metaphysis (opposite of Type A). Fully coated rod type stems fix well, but have a high incidence of stress shielding. Cemented fixation is done by surgeons for Type C bone to avoid fracture, and insure a comfortable hip. The large size stem often required to fit Type C bone causes an adverse-stem-bone ratio which can cause chronic thigh pain. I cement patients over age 70 with Type C bone which is most common in women over that age.
Aims. The distal radius is a major site of osteoporotic bone loss resulting in a high risk of fragility fracture. This study evaluated the capability of a cortical index (CI) at the distal radius to predict the local bone mineral density (BMD). Methods. A total of 54 human cadaver forearms (ten singles, 22 pairs) (19 to 90 years) were systematically assessed by clinical radiograph (XR), dual-energy X-ray absorptiometry (DXA), CT, as well as high-resolution peripheral quantitative CT (HR-pQCT). Cortical bone thickness (CBT) of the distal radius was measured on XR and CT scans, and two cortical indices mean average (CBTavg) and gauge (CBTg) were determined. These cortical indices were compared to the BMD of the distal radius determined by DXA (areal BMD (aBMD)) and HR-pQCT (volumetric BMD (vBMD)). Pearson correlation coefficient (r) and intraclass correlation coefficient (ICC) were used to compare the results and degree of reliability. Results. The CBT could accurately be determined on XRs and highly correlated to those determined on CT scans (r = 0.87 to 0.93). The CBTavg index of the XRs significantly correlated with the BMD measured by DXA (r = 0.78) and HR-pQCT (r = 0.63), as did the CBTg index with the DXA (r = 0.55) and HR-pQCT (r = 0.64) (all p < 0.001). A high correlation of the BMD and CBT was observed between paired specimens (r = 0.79 to 0.96). The intra- and inter-rater reliability was excellent (ICC 0.79 to 0.92). Conclusion. The cortical index (CBTavg) at the distal radius shows a close correlation to the local BMD. It thus can serve as an initial screening tool to estimate the local
Metal-on-metal hip resurfacing arthroplasty is a conservative procedure that is becoming an increasingly popular option for young arthritic patients most likely to undergo a secondary procedure in their lifetime. The stability of the acetabular component is of particular concern in these patients who show an increased risk of failure of the cemented acetabular cups in conventional total hip replacements. The purpose of this study was to examine the initial stability of a cementless interference press-fit acetabular cup used in hip resurfacing arthroplasty and implanted into ‘normal’ versus poor
Introduction: To obtain secondary implant stability of acetabular press-fit cups, sufficient primary stability is essential. The aim of this study was to investigate the influence of cup insertion force and
Femoral knee implants have promising outcomes, although some high-flex designs have shown rather high loosening rates (Han et al., 2007). In uncemented implants, it is vital to limit micromotions at the implant-bone interface, to facilitate secondary fixation through bone ingrowth (kienapfel et al., 1999). Hence, it is essential to investigate how micromotions of different uncemented implants are affected by various loading conditions when a range of
This is an overview of South African iliac crest bone histomorphometric findings. The examination Bone in health: a study of 346 healthy black and white South African subjects revealed thicker trabeculae and greater osteoid and erosion values in blacks. If this finding reflects greater bone turnover, then bone in blacks would be renewed more frequently and be less prone to fatigue failure. The finding of higher bone marrow cellularity in blacks is in keeping with greater bone turnover. Greater bone turnover and sturdier micro architecture may contribute to the lower fragility fracture rates in blacks. Bone disease in black teenagers is discussed. Rickets, due to dietary calcium deficiency, is associated with grotesque limb deformities and severe osteomalacia (OM). Dietary calcium deficiency was found to aggravate Rickets in endemic fluorosis. Genu valgum and varum deformities were also found to be attributable to dietary calcium deficiency. Some patients developed nutritional secondary hypoparathyroidism before going on to OM. The most severe OM was seen in boys aged 16 to 19 years. Teenagers with slipped upper femoral epiphysis were found to be osteopoenic. This may explain why the slip in blacks is more severe and more frequently bilateral than in whites. In black adults, African haemosiderosis (from traditional beer brewed in iron pots) was found to be associated with increased erosion depth and disconnection of the trabecular network. Bone formation was not impaired. Alcohol bone disease, on the other hand, showed predominantly osteoblast impairment. Patients with femoral neck fractures (FNF) had both haemosiderosis and alcohol bone disease. FNFs were found in younger black patients than white and were predominantly in males. The osteoporosis was also more severe and OM was not seen.