Prosthesis Stem Research Articles

Total Hip Arthroplasty with Modular Stem for Dysplastic Hips in South Asian Population.

Optimum component positioning and orientation is required to optimize the functional result during total hip arthroplasty for dysplastic hips. Sixty-two patients (66 hips) including 33 males and 29 females underwent total hip arthroplasty using modular stem prosthesis at an average age of 40.6 years (range 17 to 49 years). Nineteen hips were classified as Type I, 24 hips as Type II, 13 hips as Type III and 10 hips as Type IV dysplastic hips according to Crowe's classification. Eighteen hips (27.2%) underwent sub trochanteric osteotomy and 23 hips (34.8%) required adductor tenotomy at the time of surgery. Sixty-one patients (65 hips) were available for the latest follow up. The median follow-up was 57.4 months (range12 to 100 months). The mean Harris Hip Score was 90.6 (range 72 to 96), which was significant improvement from the preoperative Score of 44.8 (range 38 to 62). The clinical outcome was graded as excellent in 39, good in 13, fair in 7 patients and poor in 2 patients respectively. Only one hip (1.5%) had underwent revision surgery for the stem at 18 months following the index surgery. Postoperative dislocation following a fall was seen in one hip of a female patient who was operated on both sides. The radiographs revealed that all the remaining 65 hips had stable femoral component and the osteotomy sites were healed. The Kaplan-Meier survivorship with revision as endpoint (including open reduction for dislocation) was found to be 96.4% at 100 months (95% Confidence Interval; 86.3-99.1). This study in South-Asian patients using the modular stem strengthened the premise that cementless modular total hip arthroplasty provides a satisfactory outcome in treating secondary osteoarthritis due to dysplastic hips.

Cable plate fixation for Vancouver Type-B1 periprosthetic femoral fractures-Our experience and identification of a subset at risk of non-union

IntroductionManagement of periprosthetic femoral fractures is challenging. Vancouver classification is universally accepted for fracture description and management algorithm. Guidelines for the treatment of type B1 fracture is open reduction and internal fixation. The difficulty involved in managing this group is evidenced by the array of treatment options described in the literature. MethodsThirty two patients with Vancouver type B1 fracture treated with osteosynthesis using cable plate (between 2007 and 2015) were reviewed retrospectively. There were 21 females and 11 males with an average age of 81yrs (56–96 years). The average follow-up was 21 months. All patients were reviewed clinically and radiologically until fracture united or patient re-operated. Postoperative protocol followed was six weeks toe touch weight bearing, 6 weeks partial weight bearing and then full weight bearing if there was no displacement. Post-operative radiographs were evaluated for fracture union. Statistical analysis was done using contingency tables with Fishers exact test and a p-value < 0.05 for significance. ResultsIn twenty four patients fracture union was achieved. Non-union was recorded in four patients. Comparing the different fracture patterns all non-unions occurred in the fractures which were short oblique or transverse at the cemented stem tip (p = 0.001). Fractures were more common in female patients and associated more with the uncemented femoral stems, but it was not associated with increased rate of non-union (p = 0.68). All failed osteosynthesis were revised successfully using long stem prosthesis. Two patients died within 2 months, one patient died within 4 months, one patient was lost to follow-up. ConclusionTransverse or short oblique periprosthetic fractures around tip of cemented femoral stems can have high failure rates with just internal fixation. Revision arthroplasty may be the preferred option if possible otherwise may need to supplement fixation with cortical onlay graft. We should consider subcategorising Vancouver type B1 periprosthetic fractures into groups based on the pattern and fracture level in relation to the femoral stem.

Application of bone-retaining femoral stem prosthesis in young patients with Dorr C femoral medullary cavity

To assess the clinical efficacy of Tri-Lock bio-short prosthesis in artificial total hip arthroplasty(THA) in young patients with Dorr type C femoral medullary cavity. From January 2010 to January 2014, 35 young patients(37 hips) with in the chimney-like femoral medullary cavity received Tri-Lock BPS prosthesis of THA, including 18 males(20 hips) and 17 females with an average age of (32.2±3.0) years old ranging from 21.2 to 38.5 years old. There were 16 cases of rheumatoid hip arthritis (17 hips), 8 cases of rheumatoid arthritis (9 hips), and 11 cases of aseptic necrosis of femoral head (11 hips). All cases were complicated with different degrees of osteoporosis. According to Singh index, 26 cases were classified as Grade III and 9 cases as Grade II. Biological prostheses were used for the acetabulum, with ceramic lining and full ceramic femoral head. The proximal femoral medullary cavity was Dorr type C on anteroposterior X-ray. After replacement, X-ray examination was performed to locate the prosthesis stem. Engh and Harris criteria were used to evaluate the stability of bone-prosthesis interface and hip function, respectively. Changes of hip movement pre-operation and at last follow-up were compared. All patients were followed up for 18 to 45 months(means 33.8 months). Harris hip scores in 35 cases (37 hips) increased significantly from preoperative 61.8±3.0 (51.2 to 73.5) to 93.3±6.5 (92.5 to 98.8) points at last follow-up (t=54.745, P<0.01). The hip mobility increased from (46.5±8.0)°(0° to 55°) before surgery to(101.2±10.5)°(85° to 130°) at the last follow-up, the difference was statistically significant(t=133.091, P<0.01). Immediately after surgery, the prostheses were tightly packed with the medullary cavity. At the final follow-up, 17 hips had significant femur cortical bone thickening;12 hips had varying degrees of stress occlusal bone resorption at proximal femoral, including 9 degree I(low femur density, round and blunt) and 3 degree II(involving small rotor) hips. Meanwhile, 15 hips had significant femur cortical bone thickening without thigh pain. The cone-shaped short Tri-lock biological short-stem can fill Dorr C chimney-like medullary cavity and effectively retain good proximal femoral bone mass. Titanium microporous coating on the surface can effectively increase the friction of the prosthesis. The short-stem end in the medullary cavity can effectively avoid the occurrence of coxa varus.

Selection of femoral prosthesis stem for hip replacement in patients with femoral massive medullary cavity

Selection of femoral prosthesis stem for hip replacement in patients with femoral massive medullary cavity

Mid- and long-term effectiveness of total hip arthroplasty with Ribbed femoral stem prosthesis in 354 cases

To evaluate the mid- and long-term effectiveness of total hip arthroplasty (THA) with Ribbed femoral stem prosthesis. A clinical data of 354 patients (384 hips) with hip disease who underwent THA with Ribbed femoral stem prostheses between October 2006 and May 2016 was retrospectively analyzed. There were 171 males and 183 females, with an average age of 53.4 years (range, 20-82 years). There were 324 cases of single hip and 30 cases of bilateral hips. The cause of THA included the avascular necrosis of the femoral head in 151 cases (159 hips), hip osteoarthritis in 134 cases (136 hips), rheumatoid arthritis in 43 cases (43 hips), ankylosing spondylitis in 20 cases (40 hips), and trauma in 6 cases (6 hips). The Harris score of total 354 patients before operation was 42.34±8.89. Harris scores were used to evaluate hip function after operation. X-ray films were used to determine the length of the lower limb, the radiolucent line on the femur side, the stability of the prosthesis, and the occurrence of stress shielding. The incisions healed by first intention. All patients were followed up 2-11 years with an average of 7.4 years. The Harris score at last follow-up was 80.52±7.61, which significantly increased when compared with preoperative score ( t=134.804, P=0.000). Two cases (2 hips) of prosthetic infections, 3 cases (3 hips) of prothesis loosening, and 4 cases (4 hips) of periprosthetic fractures, and 48 cases (48 hips) of mild to moderate thigh pain occurred after operation. X-ray films showed 76 cases (78 hips) with radiolucent lines on the femur side and stress shielding. According to the Engh's method, there were 364 hips of bone ingrowth, 15 hips of fibrosis ingrowth, and 5 hips of prosthesis instability. The femoral stem subsidence occurred in 25 cases (25 hips), and the difference in leg length discrepancy was more than 10 mm in 5 patients. THA with Ribbed femoral stem prosthesis can achieve satisfactory effectiveness with good initial stability and rapid bone growth. The incidence of stress shielding is relatively high, but the stress shielding has no significant impact on the mid- and long-term survival rate and effectiveness of femoral prosthesis.

Custom Hip Stem Additive Prototyping Using Smart Materials

Although a standardized hip joint prosthesis is a quick and easy solution to repair most diseases related to the hip joint, it never satisfies the patient s personal needs due to the uniqueness of the human anatomy. Femoral hip stem geometry is one of the factors that have an important impact on prosthesis lifespan or the revision surgery frequency that occurs due to postoperative complications, such as impingement or dislocation after THR (Total Hip Replacement). In this sense, the development of a custom hip stem prosthesis starting from a standardized femoral stem can bring benefits to the patient in time, being able to reduce the failure percentage of THR. The purpose of this article is the development of a custom prosthesis based on patient s CT (Computer Tomographic) scans in order to be 3D printed with biocompatible materials, being able to serve as a study model in both engineering and medicine. Also this study represents a first step in understanding how to apply the unique distribution of mechanical properties in human bone, in order to manufacture a hip prothesis that can mimic them.

First application of three-dimensional designing total hip arthroplasty with long uncemented stem for fibrous dysplasia patients combined with hip joint osteoarthritis

BackgroundIn order to treat proximal femur fibrous dysplasia (FD) patients combined with hip joint osteoarthritis (OA), the three-dimensional (3D) designing osteotomy and implantation of femoral component was firstly used for deformity correction and total hip arthroplasty (THA). The purpose is to present the detailed design, perioperative management and evaluate short-term clinical outcomes of this novel therapeutic method.MethodA retrospective study was performed in twelve FD patients combined with hip joint OA who were treated in our hospital between July 2013 and April 2015. Seven patients received 3D designing combined osteotomy and THA, and the other five patients underwent 3D designing THA only.ResultsAll patients were followed-up with an average duration of 47 months (range, 35–56 months). There was no infection, dislocation, postoperative wound problems or mechanical failures. For the seven patients receiving 3D designing corrective osteotomy, the mean extremity lengthening was 2.8 (range, 1.5–4) cm. The average duration of bone union was 4.2 months. The average Harris Hip Score was improved from 46.08 (range, 13–67) points preoperatively to 93.72 (range, 83–100) points at the last follow-up. The average modified criteria of Guille was improved from 3.2 (range, 1–7) points preoperatively to 8.6 (range, 6–10) points at the last follow-up.ConclusionsThe 3D designing THA with long uncemented stem, including 3D designing corrective osteotomy and implantation of long prosthesis stem, seems to be a reliable method for FD patients combined with hip joint OA. Through preoperative 3D design, corrective osteotomy and implantation of long prosthesis stem can be precise to re-store alignment, uttermost preserve host bone, obtain primary stem stability and provide necessary condition for long-term stem survival, finally leading to better limb function. Besides, perioperative management should be abided strictly for late stability. Nevertheless, the outcomes of long-term follow-up and larger cases are still required.

Uncemented extensive porous titanium-coated long femoral stem prostheses are effective in treatment of Vancouver type B2 periprosthetic femoral fractures: A retrospective mid- to long-term follow-up study.

The aim of this study was to evaluate the mid- to long-term outcomes of revision surgery for Vancouver type B2 periprosthetic femoral fractures (PFFs) after total hip arthroplasty using an uncemented extensive porous titanium-coated long femoral stem prosthesis (solution prosthesis) with or without cortical strut allograft. A total of 34 patients with Vancouver type B2 PFFs who underwent revision hip arthroplasty using a posterolateral approach and received a solution prosthesis at our institution from December 2006 to January 2014 were retrospectively recruited. Patients were asked to assess their walking ability and pain status using a questionnaire. Limb function, pain, and physical and mental health were assessed using the Harris Hip score, University of California-Los Angeles score, Western Ontario and McMaster Universities osteoarthritis index, and Short Form-12 Health Survey score. Patients were also asked to rate their satisfaction with the surgery. Fracture union and stress shielding were assessed by radiography, and computed tomography was used to assess stem fixation. Single-photon emission computed tomography performed to assess radionuclide distribution in patients given cortical strut allografts. Patients were asked about their condition before PFF and evaluated at 6 weeks, 3 months, 6 months, 1 year, and annually after surgery. Any complications during follow-up were recorded. Of the 34 patients, 29 completed follow-up. There was no significant difference in patient's health before PFF or at the last follow-up. Fracture union was achieved in all patients. Mild-to-moderate stress shielding occurred in three patients, and no patients exhibited femoral stem loosening or obvious subsidence. Radionuclides were concentrated in the cortical strut transplantation area, and the cortical strut was integrated with the host femur. The incidence of postoperative complications was low. Revision surgery using the solution prosthesis with or without cortical strut allograft is effective in treating Vancouver type B2 PFFs, with satisfactory mid- and long-term clinical and radiological outcomes.

Finite Element Analysis and Biomechanical Testing of the New MiniMIS Short Stem.

In hip arthroplasty a trend towards short stem prostheses is observed. The aim of this study is to investigate the finite element analysis and biomechanical fatigue performance of a new short stem prosthesis. A finite element analysis was used to simulate the stresses during neck and stem loading according to the ISO standards. Numerical analysis with applied forces of up to 6 kN were performed in the vertical direction on a femoral neck-preserving stem (MiniMIS). During experimental testing, 10 million cycles with a maximum load of 5.34 kN using the worst case of a XL ceramic head (36 mm) were applied. This was followed by a Locati test, where the load was increased until failure of the stem. For all stems, stress values below the limits according to the ISO 5832-3 standard (yield strength of 800 N/mm2) were calculated by the finite element analysis. In the biomechanical tests, the total number of 10 million cycles with a maximum load of 5.34 kN was reached in all cases without any visible signs of implant damage. The estimated load to failure after stem testing was 2.16 kN (required by ISO 7206-4: 1.2 kN) and after neck testing > 9.35 kN (required by ISO 7206-6: 5.4 kN). The presented finite element calculation and subsequent biomechanical testing show that the design of this stem meets the essential mechanical requirements given by the ISO and a material failure is not expected in all variants tested under the applied boundary conditions.

Partial two-stage exchange for periprosthetic joint infection after total hip arthroplasty

Objective To evaluate the early stage effects of partial two-stage exchange (PTE) for infection after total hip arthroplasty (THA) in order to improve surgical treatment outcomes. Methods Twelve patients (7 males and 5 females) of infected THA treated by PTE between September 2000 and February 2016 were included with an average of 59 years old (range, 40-74 years old). The femoral stem prosthesis was preserved when we ensured that it was not infected and with well fixation during operation. The acetabular prosthesis was totally replaced. Furthermore, the secondary surgery was performed on patients who were free from infection for at least 3 months. At the follow-up duration, the pelvic X-ray was examined to access the presence of loosening of the prosthesis. The inflammatory index was recorded. Hip function was assessed by the Harris hip score, and the visual analogue score (VAS) and patient's subjective satisfaction were recorded by the questionnaire. Results All of the 12 patients were followed up for a mean of 33.3 months (range, 24-48 months). We achieved a 92% (11/12) success rate. One patient resuffered infection, which was controlled after the second debridement. The preoperative Harris score of 12 patients was 23-57, with an average of 40.83±10.62. All patients had significant improvement in hip function after PTE. The Harris score reached 59.58±4.34 at one month after surgery, and reached 64.58±9.08 after three months and 86.75±4.58 at the last follow-up. There was significantly different when compared with the preoperative Harris score. At the last follow-up, the length difference between the lower limbs was less than 1cm in all patients. Two patients did not complain of pain, while other 10 patients got a VAS score of less than 2 points. The patient's subjective satisfaction rating was 100%. Conclusion PTE could be a valuable alternative treatment for infection after THA. The infection control rate and clinical outcomes are comparable to those of two-stage exchange. Key words: Arthroplasty, replacement, hip; Prosthesis-related infections; Device removal

Periprosthetic humeral fractures: from osteosynthesis to prosthetic replacement

Stabilization of the humeral shaft and the restoration of shoulder function dependent on the osseous integrity of the prosthetic stem component. In cases of astable prosthesis stem, an isolated plate osteosynthesis is possible. Prosthesis stem replacement is indicated in cases of aloose stem. With sufficient bone stock of the proximal humeral segment, achange to ashorter humeral shaft component with subsequent plate fixation of the fracture is possible. If the bone stock is poor, conversion to along revision stem is necessary. Inoperability of the patient due to serious comorbidities. Advanced age and low demands on shoulder function are relative contraindications for complex prosthesis replacements. Plate osteosynthesis can be done through an anterior or posterior approach, stem replacement only from anterior deltopectoral approach. When changing humeral shaft components, the loose shaft and all cement residues are removed, the fracture is reduced and, if possible, ashorter shaft is implanted with subsequent plate osteosynthesis of the fracture. When changing to along revision stem, additional osteosynthesis with cerclages wires is usually sufficient. In case of poor bone stock, an additive autologous or allogenic bone grafting can be performed. An instable anatomical prosthesis with poor shoulder function may require conversion to an inverse prosthesis. In cases of an isolated plate osteosynthesis with an otherwise stable prosthesis, immediate active rehabilitation of the upper limb is advocated. When aprosthesis replacement and conversion to an inverse prosthesis is performed the shoulder is immobilized in 30°abduction for 6weeks. Passive and after 3weeks active-assistive shoulder movement up to 90°abduction and flexion is allowed. In 40patients with aperiprosthetic humeral fracture, an isolated plate osteosynthesis was performed in 30cases and aprosthesis replacement in 10cases. Complications included 3infections and 3temporary radial nerve palsies. Revisions due to pseudarthrosis were necessary in 2cases.

Additively manufactured femoral stem topology optimization: case study

Abstract The main problem of femoral stem prostheses is their primary stability after implantation, which is assured by the so-called press-fit implantation. After implantation, the second requirement is to achieve a secondary stability, due to the osseointegration of the prosthesis in the bone of the femur. Additive manufacturing (AM) allows the designer to create tridimensional models that can have a diffused porosity in the contact area with the bone, which could confer significantly higher osseointegration. Furthermore, through topology optimization, the shape of the prosthesis can be improved, in conjunction with significant mass reduction. This work presents our results concerning the topology optimization of a medium length femoral stem, intended to be manufactured by powder bed fusion (PBF). The CAD models have been analyzed through computer-aided simulations concerning their mechanical characteristics, according to the ISO 7206/4 and ISO 7206/6 standards, and were topologically optimized using commercially available software. The CAD models, both original and optimized, have been analyzed concerning their mechanical characteristics. An optimized femoral stem has been obtained, which answers to the ISO 7206/4 and ISO 7206/6 standards, but with a 15% mass reduction.

Finite element analysis on the hollow porous design at the proximal end of cementless femoral prosthesis stem

The present study aims to improve the design of cementless femoral prosthesis stem and achieve better bone ingrowth and long-term stability. Four models with different directional hollow holes at the proximal end of femoral prosthesis were designed and finite element analysis was applied to calculate the magnitude of conducting force within the differently angled holes and the stress distribution of the femur and prosthesis. Holes in prostheses make no difference on the stress values of femoral inner walls. The conducting forces in models trepanned on the lateral plane were 6.60N (0° pore) and 8.40N (45° pore) while forces in models trepanned on the anterior-posterior planes were 0.45N (upper 0° pore), 0.48N (lower 0° pore) and 1.57N (upper 45° pore), 1.51N (lower 45° pore), respectively. The position and direction of hollow holes influenced the conducting force in holes but had no influence on stress values of femoral inner walls. Prostheses with one 45° hole trepanned on the lateral plane of proximal prostheses presented best in elevating conducting force.

Bio-inspired redesign of a hip prosthesis stem for improving geometrical optimization time

It has been investigated the potential application of a bio-inspired 3D model for decreasing the time required to perform the geometrical optimization of a hip prosthesis stem. This research assumes that nature has already found the best solution for many situations, proved to be real for many cases, what has been demonstrated for the specific situation of a femur in this study. The application of bio-inspired 3D models can save up to a 35% of the time when geometrical optimizations are going to be performed.

Patient-specific design process and evaluation of a hip prosthesis femoral stem.

There are several commercially available hip implant systems. However, for some cases, custom implant designed based on patient-specific anatomy can offer the patient the best available implant solution. Currently, there is a growing trend toward personalization of medical implants involving additive manufacturing into orthopedic medical implants' manufacturing. This article introduces a systematic design methodology of femoral stem prosthesis based on patient's computer tomography data. Finite element analysis is used to evaluate and compare the micromotion and stress distribution of the customized femoral component and a conventional stem. The proposed customized femoral stem achieved close geometrical fit and fill between femoral canal and stem surfaces. The customized stem demonstrated lower micromotion (peak: 21 μm) than conventional stem (peak: 34 μm). Stress results indicate up to 89% increase in load transfer by conventional stem than custom stem because the higher stiffness of patient-specific femoral stem proximally increases the custom stem shielding in Gruen's zone 7. Moreover, patient-specific femoral stem transfers the load widely in metaphyseal region. The customized femoral stem presented satisfactory results related to primary stability, but compromising proximo-medial load transfer due to increased stem cross-sectional area increased stem stiffness.

Effects of Stem Malalignment in Cementless Hip Arthroplasty: a Computational Study

Implant loosening and deformation issues contribute to the instability of the hip arthroplasty. Prosthesis stem malalignment can occur in varus, anteversion and retroversion in different degrees due to several reasons. In this study, computational analysis of cementless hip arthroplasty with different stem malalignment cases was conducted to investigate the biomechanical effects in hip arthroplasty. Five hip arthroplasty models were developed using finite element analysis which are straight/aligned model, malalignment models at varus +3°, varus -3°, sagittal flexed +3°, and sagittal extended -3°. Results show that different pattern of stress distribution was observed in each malalignment case. The varus -3° malalignment model had demonstrated the greatest risk of failure based on the resulting stress distribution and total deformation.

Comparison of collum femoris-preserving stems and ribbed stems in primary total hip arthroplasty

BackgroundThis retrospective study investigated the relative benefits of using a collum femoris-preserving prosthesis or ribbed stem during total hip arthroplasty (THA).MethodsThe clinical results were compared of patients who underwent THA, between January 2010 and December 2012, with either a CFP prosthesis or a ribbed stem (66 and 75 patients, respectively, aged 43.4 ± 10.8 and 42.3 ± 9.8 years). Patients were assessed using the Harris Hip Score (HHS), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), 12-Item Short Form Health Survey (SF-12), and physical component summary (PCS) score. Intraoperative and postoperative complications and leg-length differences were noted.ResultsThe mean follow-up times of the CFP and ribbed groups were 67.2 ± 7.5 and 68.3 ± 7.2 months, respectively. The HHS, SF-12 MCS, SF-12 PCS, and WOMAC scores of the two groups were similar. The rates of periprosthetic femoral fractures and leg-length differences > 10 mm in the CFP group (10.6% and 13.6%, respectively) were significantly higher than those in the ribbed group (1.3% and 2.7%). The groups were similar regarding complications of osteolysis, ectopic ossification, dislocation, deep infection, deep venous thrombosis, thigh pain, and aseptic loosening. The survival rates of the CFP and ribbed groups were comparable (98.5% and 97.8%).ConclusionThe clinical results of the CFP and ribbed prostheses in young patients given THA were similar for Chinese patients. However, the CFP stem should be used with caution, given the high incidence of technical problems associated with implantation especially for Chinese patients.

Long-term results of an anatomically implanted hip arthroplasty with a short stem prosthesis (MiniHipTM).

AIMTo evaluate the clinical and radiological outcome nine and ten years after short-stemmed, bone preserving and anatomical hip arthroplasty with the MiniHipTM system.METHODSIn a prospective study, 186 patients underwent hip arthroplasty with a partial neck preserving short stem (MiniHipTM, Corin). Elderly patients were not excluded from this study, thus the mean age at the time of surgery was 59.3 years (range 32 to 82 years). Surgery and the follow-up assessments were performed at two Centers. Up until now, the mean follow-up was 112.5 ± 8.2 mo. The Oxford Hip Score (OHS) and the Hip Dysfunction Osteoarthritis and Outcome Score (HOOS) was assessed pre- and each year after surgery. The clinical follow-up was accompanied by standardized a.p. and axial radiological examinations. Periprosthetic lucencies, hypertrophies within the Gruen zones one to fourteen were assessed. A subsidence of the stem was investigated according to Morray and heterotopic ossifications were assessed according to Brooker.RESULTSThe OHS and HOOS improved from 18 ± 3.3 to 46 ± 2.0 and from 30 ± 8.3 to 95 ± 4.6 points, P < 0.001 respectively. There were no differences regarding age, etiology, friction pairings, etc., (P > 0.05). Two stems were revised due to a symptomatic subsidence four and twelve months postoperatively. Thus, the survivorship for aseptic loosening at nine to ten years was 98.66%. Including one stem revision due to a symptomatic exostosis, bursitis and thigh pain as well as one revision because of a septic stem loosening, the overall survival for the stem with revision for any reason was 97.32%. Besides one asymptomatic patient, radiological signs of a proximal stress-shielding, such as bone resorptions within the proximal Gruen zones, were not noticed. Findings suggesting a distal loading, e.g., bony hypertrophies or bone appositions of more than 2 mm, were also not detected.CONCLUSIONRegarding these first long-term results on the MiniHipTM, the implant performed exceedingly well with a high rate of survivorship for aseptic loosening. Our radiological results within the Gruen zones support the design rationale of the Minihip to provide a reliable metaphyseal anchoring with the expected proximal, more physiological load transfer. This might minimize or exclude a stress shielding which might be associated with thigh pain, proximal bone loss and an increased risk of aseptic loosening. The MiniHipTM is a reliable partial-neck retaining prosthesis with good a clinical long-term outcome in younger as well as elderly patients.

Progress in repair and reconstruction of large segmental bone tumor defect in distal tibia

To review the methods of repair and reconstruction of the large segmental bone tumor defect in distal tibia. The related literature of repair and reconstruction of the large segmental bone tumor defect in disatal tibia were reviewed and analyzed from the aspects of the reserved ankle joint and the non-reserved ankle joint. The large segmental bone tumor defect in distak tibia is not rare in clinical. In addition to conventional allograft bone transplantation, vascularized autologous fibular transplantation, vascularized fibular allograft, inactivated tumor regeneration, distraction osteogenesis, and bone transport techniques; membrane-induced osteogenesis, artificial tumor stem prosthesis, three-dimensional printed metal trabecular prosthesis, ankle arthrodesis, artificial tumor ankle joint placement surgery are now gradually applied to the repair and reconstruction of large segmental bone defects in the distal tibia. Moreover, due to its long survival time, the function of reconstruction of the bone tumor defect in the distal tibia has also received increasing attention. Although the ideal methods of repair and reconstruction of the large segmental bone tumor defect in the distal tibia has not yet been developed, great progress has been achieved. Recently, with the appearance of three-dimensional printing and various preoperative simulation techniques, personalized and precise therapy could become ture, but therapies for the large segmental bone tumor defect in the distal tibia still need to be further explored.

Are short-stem prostheses superior to conventional stem prostheses in primary total hip arthroplasty? A systematic review and meta-analysis of randomised controlled trials

ObjectiveCementless total hip arthroplasty (THA) is associated with reliable clinical results and high patient satisfaction. Short-stem prostheses (SS) were designed to achieve superior preservation of proximal bone stock and stability...