Short-stem Prosthesis Research Articles

Does the calcar femorale affect the position of uncemented short stems?

Metaphyseal-stabilised short stems rely on sufficient metaphyseal fixation and are inserted by following the medial cortex. This type of stem is used extensively in our institution, and we observed on occasion unintended implant positioning with an increased distance between the implant and the medial cortex. A bony structure within the proximal femur which was first described in 1874 and named the calcar femorale, coincides with this phenomenon.The aim of this study was to investigate the impact of the calcar femorale on the position of a metaphyseal-stabilised short stem. The frequency of cases with an increased distance between medial cortex and the implanted short stem was analysed in 52 consecutive patients. Additionally, we performed an anatomical CT study with 60 cadaveric femora to obtain more detailed information on the anatomy of the calcar femorale. Detailed measurements regarding the calcar femorale and its relationship to the proximal femur were obtained. From this, we derived implications for the implantation of a short stem prosthesis. In 50% of all cases, we found an increased gap between the stem and the medial cortex. An increased gap did not significantly affect stem size, position, or subsidence rate, but in cases with an increased gap we found fewer stems with a radiologically optimum fit. The calcar could be identified in all 60 cadavers. The calcar femorale angle showed a high correlation with the mechanical antetorsion (0.87, p = 0.02) and the functional antetorsion (0.86, p = 0.05) of the femur. The calcar femorale is a consistent anatomical structure which may be the cause for an increased gap medial to the short stem in 50% of our cases. It limits the intramedullary space and influences both stem size and orientation. The CF angle which correlates with femoral antetorsion may influence the anteversion of the stem.

Collum Femoris-Preserving Hip Stem: Clinical and Radiographical Results from a Medium-Term, Multi-Centric Study in a Latin American Population

Background: There is a lack of information related to the medium-term results of short stem prosthesis in the Latin-American population. This study represents the longest follow-up results of the CFP prosthesis in the Latin-American population. Methods: Two-hundred fifty-five patients treated with anatomic neck preserving from June 2013 to June 2020 were enrolled in the current study. The mean follow-up was 81 (60-96) months. All the subjects were available for the follow-up examination at a minimum of 5 years after surgery. Clinical results were assessed using Oxford Hip Score (OHS). Radiologic assessment was performed at each follow-up. Results: Follow-up was 81 (60-96) months. Two-hundred fifty-five patients were contacted. The patients with hip dysplasia were operated with the CFP stem in 10.2% of all cases; with regards to the Dorr classification of the proximal femur, type 1: 9.8%; type 2: 88.6% and type 3: 1.6%. The overall prosthesis survival was 96.1%. The functional results were OHS pre: 9.1 (3-35), post: 44.4 (27-48). Conclusion: The surgeries with CFP stem have excellent clinical results. The main indication of this short stem is primary hip osteoarthritis; nevertheless, we have some experience in dysplastic hips with good clinical results and survivorship. The results are comparable in terms of survivorship when this stem is implanted in Dorr 1, 2 and 3; however, we had a limitation, the sample was not comparable in the three groups. The overall survivorship, the functional scales and the radiographical results in the Latin-American population are comparable with literature reported around the world. Level of Evidence: Level III

Comparison of Short Uncemented Metaphyseal Stem and Long-Stem Reverse Shoulder Arthroplasty in Proximal Humerus Fractures: Preliminary Study at 2-Year Follow-Up.

Introduction: In the last few years, short metaphyseal-socket prosthetic humeral stems have been introduced for reverse shoulder arthroplasty (RSA). A short stem may have advantages in humeral force distribution, reducing shear stress and preserving bone stock, keeping in mind the need for possible future revision surgery. The main objective of our study was to validate the use of a short stem prosthesis in the surgical treatment of humeral fractures by comparing clinical and radiological outcomes of our studied implant with those obtained with the use of traditional long-stem implants. Methods: In this multicentric, controlled prospective study, 125 patients with proximal three- or four-fragment humerus fractures were selected and treated with RSA. A short stem was used in group A (n = 53, mean age: 75.6 ± 5.6 years old), and a long stem was used in group B (n = 72, mean age: 71.76 ± 3). Active range of motion (ROM), Constant score (CS), Quick DASH, American Shoulder and Elbow Surgeons Shoulder (ASES) score, and Visual Analog Scale (VAS) scores were collected and analyzed at 2 years mean follow-up, as well as humeral and glenoid bone resorption (sum Inoue scores and Sirveaux scores were used). Results: No statistically significant differences were observed between group A and B in ROM, Constant score (51.69 ± 15.8 vs. 53.46 ± 15.96, p > 0.05), Quick DASH (31.5 ± 21.81 vs. 28.79 ± 13.72, p = 0.85), ASES (82.53 ± 17.79 vs. 84.34 ± 15.24, p = 0.57), or the VAS (0.53 ± 1 vs. 0.56 ± 1.07, p = 0.14) at the final follow-up. No statistically significant differences were found in the radiographic parameters between the two groups. No statistically significant differences were found for the average degree of humeral and glenoid bone resorption either. Conclusions: The use of a short metaphyseal-socket stem can be considered a safe, effective, and feasible option in reverse shoulder arthroplasty for treating proximal humerus fractures. Our results are encouraging, with no statistically significant differences identified between the proposed treatment and traditional long stems.

Cemented Calcar-Guided Short-Stem Prostheses in Geriatric Patients: Short-Term Results from a Prospective Observational Study.

Both cementless and cemented stems have exhibited favorable long-term outcomes in total hip arthroplasty. Nonetheless, in elderly patients, cemented hips offer an advantage due to their reduced risk of periprosthetic fractures. This study aimed to assess the initial outcomes of 28 patients who underwent unilateral cemented total hip arthroplasty utilizing a calcar-guided A2 stem (ARTIQO GmbH, Lüdinghausen, Germany). Various types of antibiotic-loaded bone cement were employed. During follow-up, we recorded demographic data and comorbidities and employed standardized clinical assessment tools, including the Harris Hip Score. Radiographic assessments included preoperative, postoperative, and follow-up imaging to evaluate subsidence, osteolysis, and bone resorption. The results indicated that among the 28 patients, 5 withdrew consent and 2 patients passed away from unrelated causes. Additionally, one prosthesis was explanted due to the undersizing of the cement stopper, which resulted in an inadequate cement mantle. As a result, 20 patients underwent a 1-year follow-up, revealing noteworthy enhancements in clinical scores, with no instances of radiolucent lines or osteolysis. No infections were detected. In summary, our short-term experience with this particular cemented short-stem design yielded promising results, exhibiting excellent functional outcomes, no aseptic loosening attributable to the stem, and no infections. Further clinical studies and registry data are essential to corroborate these findings.

Effect of Stem Design and Positioning on the Leg Axis after Total Hip Arthroplasty: A Secondary Analysis.

Background/Objectives: Various parameters, like femoral offset and leg length, are associated with good patient outcomes after total hip arthroplasty. In this prospective study, the effects of stem design, its placement in the proximal femur and the resulting femoral offset on the total leg axis were investigated. Methods: The 27 patients included in this study received biplanar radiography (EOS®, EOS Imaging) with 3D reconstruction using sterEOS® both preoperatively and postoperatively. For all leg alignment parameters obtained from the 3D reconstruction and from measurements using mediCAD, the deltas between the postoperative and preoperative values were determined. Patients were divided into those who received a short-stem prosthesis and those who received a straight-stem prosthesis. Results: The change in femoral offset with the implantation of a short-stem prosthesis was significantly greater than that with the implantation of a straight-stem prosthesis (11.4 ± 5.9 vs. 4.6 ± 7.4 mm, p = 0.014). Compared with the straight-stem implantation, short-stem implantation caused a significantly greater increase in the varus orientation of the leg (-1.4 ± 0.9 vs. -0.4 ± 1.4°, p = 0.048). There was no significant difference in the positioning of the short-stem prosthesis compared to the straight-stem prosthesis in the proximal femur (3.6 ± 3.1 vs. 2.6 ± 1.9°, p = 0.317). Conclusions: These findings substantiate the impact of prosthesis design on offset and leg alignment. The implantation of short-stems is more variable and requires precise planning. Intraoperative non-physiological offset changes and varus deviation of the leg axis should be avoided. Trial registration: This study was retrospectively registered with the German Clinical Trials Register (DRKS) under the number DRKS00015053 on the 1 August 2018.

Analysis of Postoperative Complication and Revision Rates and Mid- to Long-Term Implant Survival in Primary Short-Stem Total Hip Arthroplasty.

Background/Objectives: Short-stem prostheses were introduced as an alternative to conventional straight-stem prostheses. Despite their benefits, including minimally invasive approaches, soft-tissue- and bone-sparing implantation, and physiological load transfer to the metaphysis, data on postoperative complication and revision rates as well as on implant survival are scarce. Methods: A retrospective analysis of 1327 patients who underwent primary total hip arthroplasty (THA) using the Metha® short stem between 2006 and 2023 was conducted. Complication and revision rates were analysed for the intraoperative, direct postoperative, and follow-up episodes. Implant survival was analysed with the endpoint of all-cause stem revision. Results: Intraoperative complications were observed in 3.77% of the cases and included 44 hairline cracks and 6 fractures. In 15 cases (30.0%), conversion to a straight-stem or revision implant was necessary. The direct postoperative complication rate was 2.44%, and 11 revision procedures were performed during inpatient stay (0.84%). Mean follow-up was 7 years (range 1-17). During follow-up, femoral component revision was performed in 60 cases. Aseptic loosening and stem subsidence accounted for a combined percentage of 80% of all indications. Implant survival rate was 95.66% after 5 years, 95.58% after 10 years, and 95.50% after 15 years. Conclusions: Our study provides a comprehensive analysis of postoperative complication and revision rates in a large sample undergoing primary short-stem THA. Postoperative complication rates were favourable, and the long-term implant survival rates were comparable to conventional straight-stem prostheses. Therefore, short-stem THA may be considered an alternative for younger patients.

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

IntroductionShort 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. Methods118 patients aged over 60 received short stem prostheses. Clinical examination included Harris Hip Score (HHS) and Hip Disability and Osteoarthritis Outcome Score (HOOS). 93 patients were followed clinically for at least five years. 53 patients underwent dual-energy x-ray absorptiometry (DXA) and radiographic evaluation. Follow-up intervals were preoperative and postoperative (t0), at approximately six months (t1), at approximately two years (t2), and at approximately five years or later (t3). ResultsOver a mean 6.7-year observation period for all 118 patients, one stem revision occurred due to a traumatic periprosthetic stem fracture. The five-year survival rate for the endpoint survival of the Metha® stem in 95 at-risk patients is 99.2%. HHS improved significantly from t0 55.3 ± 11.5 (range 30–79) to t3 95.3 ± 8.6 (range 57–100) at a mean of 8.0 years (p < 0.001). HOOS improved significantly in each subscale (p < 0.001). Bone mineral density (BMD) was available for review in 53 patients after a mean of 7.1 years. BMD increased from t0 to t3 in region of interest (ROI) 3 (+0.4%) and ROI 6 (+2.9%) and decreased in ROI 1 (−10.3%), ROI 2 (−9.8%), ROI 4 (−5.3%), ROI 5 (−3.4%) and ROI 7 (−23.1%). ConclusionsThe evaluated short stem prosthesis shows a remarkably high survival rate in elderly patients, accompanied by excellent clinical results. Load transfer measurements show a metaphyseal-diaphyseal pattern with a trend towards increased diaphyseal transfer over the period observed.

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

IntroductionIn 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. MethodsBasic CAD models based on an established short stem prosthesis were created and evaluated using finite element analysis. The best design was further developed to achieve a more deformable stem while maintaining stability. The model was validated through in vitro testing. ResultsThe “H-Beam” short stem showed a higher degree of deformation of approximately 142–144% compared to the established short stem. The FE model had a relative error of 0.98% and 1.07% compared to the in vitro tests. An operating procedure was outlined for this new short stem design. DiscussionThe FE model is deemed valid due to small differences in comparison to in vitro testing. The short-stem prosthesis is more flexible and can be easily adapted to individual anatomy during surgery. The prosthesis length is similar to conventional prostheses, but the new stem design could allow better and faster osteointegration while preserving the cancellous bone structure.

Ten-year follow-up and clinical outcome of a metaphyseal anchoring short hip stem prosthesis: a retrospective single-centre analysis.

Short stems for total hip arthroplasty are an alternative to traditional conventional long stems. Short stems are designed to facilitate minimal-invasive surgery, improve bone-stock preservation, and mimic a physiological load distribution. However, there is little evidence of the long-term outcome of short stems. This study aims to analyze the tenyear survival rates and clinical outcome of one specific metaphyseal short hip stem implant. We retrospectively analyzed the patient records of the patients who underwent a total hip arthroplasty with a monoblock partial collum sparing metaphyseal short hip stem prosthesis in 2008 and 2009 in our clinic. Patients were contacted, and clinical follow-up was recorded using the German version of the modified Harris Hip Score. Furthermore, complications, revision surgery, and post-operative radiographs were analyzed. Data from 339 primary implantations in 322 patients were retrieved. The mean follow-up was 10.6years. Seven patients underwent a revision. The tenyear survival rate with any revision surgery as the endpoint was 97.5%. The mean modified Harris Hip Score was 86 points (range 30 to 91 points). Five patients had an intraoperative fracture of the femur (1.6%). Two patients (0.6%) had a dislocation of the hip. The stem tip-to-cortex distance, measured in the anterior posterior view, was 2.6mm (range 0 to 8.3mm). The tenyear survival rate of our used monoblock partial collum sparing metaphyseal short hip stem implant is comparable to traditional stems for total hip arthroplasty.

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

IntroductionSelf-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 methodsThe learning process of one surgeon was analysed in 133 cases of hip arthroplasty. These were divided into seven groups representing the surgical years 2008–2014. Over the course of 3 postoperative years, a total of 655 radiographs were analysed at regarding three radiological quality parameters (centrum-collum-diaphyseal angle (CCD angle), intramedullary fit&fill ratio (FFR), and migration) and ancillary outcome parameters (Harris Hip Score (HHS), blood loss, operating time, and complications). This period was divided into five times: 1st-day post-op, 6 M, 12 M, 24 M, and 36 M. Bivariate Spearman's correlation analysis and pairwise comparisons were performed.ResultsThe total collective achieved a proximal FFR of over 0.8. The distal prosthesis tip migrated and was located on the lateral cortex within the first months. The CCD angle initially showed a variation with a subsequent constant course. The HHS showed a significant increase (p < 0.001) to over 90 points postoperatively. Over time, the operating time and blood loss decreased. Intraoperative complications existed only at the beginning of the learning phase. A learning curve effect can be determined for almost all parameters by comparing the subject groups.ConclusionsOperative expertise was shown to gain through a learning curve, whereby postoperative results corresponded to the system philosophy of the short hip stem prosthesis. The distal FFR and the distal lateral distance could represent the principle of the prosthesis, which overall could be an interesting approach for verification of a new parameter.

Stress shielding effect after total hip arthroplasty varies between combinations of stem design and stiffness—a comparing biomechanical finite element analysis

PurposeTotal hip arthroplasty (THA) has become a highly frequent orthopaedic procedure. Multiple approaches have been made to design the femoral component for THA with a mechanical behaviour as close as possible to a natural femur. The aim of this study was to compare different combinations of design and biomechanical properties of THA prostheses and their impact on stress shielding of the periprosthetic bone.MethodsVirtual implantation of different stem designs (straight standard stem, straight short stem, anatomical short stem) by finite element analysis based on in vivo data from computer tomography was performed. For each stem, three grades of stiffness were generated, followed by a strain analysis.ResultsReduction of stem stiffness led to less stress shielding. Implantation of an anatomical short-stem prosthesis with low stiffness provided the most physiological strain-loading effect (p < 0.001).ConclusionA combination of a short and an anatomically designed stem with a low stiffness might provide a more physiological strain transfer during THA. Biomechanical properties of the femoral component for THA should be considered as a multifactorial function of dimensions, design, and stiffness.

Bone Remodelling of the Proximal Femur After Hip Revision with a Metaphyseal-Fixation Femoral Stem Component.

Whether hip revision with a metaphyseal-fixation femoral stem component can restore the bone mass of the proximal femur remains unclear. The aims of this study were to identify whether the bone mineral density (BMD) of the proximal femur increases following hip revision with a metaphyseal-fixation femoral stem and to identify the factors associated with BMD recovery. This was a retrospective study involving 36 patients who underwent hip arthroplasty with a metaphyseal-diaphyseal fixation stem (standard length stem) and had indications for hip revision, which was performed with a proximal press-fit short-stem prosthesis for each patient. Dual-energy X-ray absorptiometry (DEXA) was used to obtain, evaluate, and compare the BMD at baseline and one year and two years postoperatively. The proximal femur was divided into several independent areas according to the Gruen zone (Gruen 1 to Gruen 7 from the greater trochanter counterclockwise to the lesser trochanter). Logistic regression analyses were used to assess potential factors significantly associated with an increase in BMD. An increased BMD was obviously identified in the proximal femur. Two years after the surgery, the BMD of the Gruen 1, Gruen 2, Gruen 6, and Gruen 7 areas had increased by 22.6%, 12.6%, 16.2% and 24.2%, respectively, relative to baseline. Three independent risk factors associated with bone mineral density recovery were identified: age (OR=1.100, 95% CI=1.005-1.203, P=0.038), osteoporosis (OR=14.921, 95% CI=1.223-182.101, P=0.034) and fair to poor hip function (OR=13.142, 95% CI=1.024-168.582, P=0.048). This study confirms that metaphyseal-fixation stem hip revision can indeed help restore bone mass in the proximal femur, especially in the Gruen 1, Gruen 2, Gruen 6 and Gruen 7 zones. It was also found that advanced age, osteoporosis, and fair to poor hip joint function were three important risk factors affecting the recovery of proximal femur bone mass after surgery. Retrospectively registered.

Revision of anatomic shoulder arthroplasty

With the increasing number of primary arthroplasties, revisions of anatomical prostheses are becoming increasingly important. The most common reasons for revision are glenoid loosening, including protrusion, rotator cuff insufficiency, including instability, and early/late infection. The reconstruction of glenoid defects can be done with an autograft or allograft. Depending on the size and situation, it is carried out in one or two stages. The stemless humeral head replacement and the short-stem prostheses that have been used more frequently in recent years have significantly simplified humeral revision. Platform systems take adifferent approach with the option of conversion without major interventions on the glenoid or revision stem. Intraoperative complications mainly occur on the humeral side. Postoperative complications include dislocation, component loosening, and infection. Revision of anatomical to reverse arthroplasty shows better clinical outcomes and lower complication rates than anatomical revision.

Classification and reconstruction of femoral bone defect in the revision of aseptic loosening of distal femoral endoprostheses: a 10-year multicenter retrospective analysis

ObjectiveThis study proposes a system for classifying the aseptic loosening of distal femoral endoprostheses and discusses reconstruction methods for revision surgery, based on different classification types.MethodsWe retrospectively analyzed the data of patients who received revision surgery for aseptic loosening in distal femoral tumor endoprosthesis from January 2008 to December 2020 at 3 bone tumor treatment centers in China. Based on the patient imaging data, we proposed a classification system for the aseptic loosening of distal femoral endoprostheses and discussed its revision surgery strategy for various bone defects.ResultsA total of 31 patients were included in this study, including 21 males and 10 females aged 15–75 y (average: 44.3 y). First-revision surgery was performed on 24 patients, whereas second-revision surgery was conducted on 7 patients. The 31 patients were classified into different types based on the degree of aseptic loosening: Type I, 12 patients (38.7%); Type IIa, 7 patients (22.5%); Type IIb, 7 patients (22.5%); Type III, 4 patient (12.9%); and Type IV, 1 patient (3.2%). For type I, 11 patients underwent revisions with standard longer-stem prostheses (one with the original prosthesis), and one patient had the original prosthesis plus cortical allograft strut. For type II (a and b), 10 patients underwent revisions with original prosthesis or longer-stem prosthesis and 4 patients combined with cortical allograft strut. For type III, one patient underwent revision with a longer-stem prosthesis and the other 3 patients with a custom short-stem prosthesis. For type IV, only one patient underwent revision with a custom short-stem prosthesis.ConclusionsAseptic loosening of the distal femoral prosthesis can be divided into 4 types: type I, type II (a, b), type III and type IV. The reconstruction methods of our centers for different types of bone defects can offer some reference value in the revision of aseptic loosening.

Stemless and stemmed total shoulder arthroplasty: a comparison of short-term clinical and radiographic outcomes

BackgroundStemless total shoulder arthroplasty could provide benefits over stemmed arthroplasty which has represented the gold standard for decades. Proposed benefits of stemless arthroplasty include better reproduction of anatomy and reduction in stress shielding; however, this does not appear to be confirmed by any study. The hypothesis was there would be no clinical differences between the stemless and the short-stem prosthesis, but the stemless prosthesis would better reproduce coronal radiographic anatomy and have less radiographic evidence of stress shielding. Materials and MethodsA prospectively collected data of patients undergoing primary, anatomic total shoulder arthroplasty for osteoarthritis were retrospectively reviewed. Patient-determined outcomes including the Western Ontario Osteoarthritis Index, American Shoulder and Elbow Surgeons score, Single Assessment Numeric Evaluation, Simple Shoulder Test, and Shoulder Activity Level were recorded preoperatively, at 1 year, and at 2 years. Preoperative and 1-year postoperative range of motion was recorded. Radiographic parameters to assess restoration of proximal humeral anatomy included humeral head height, humeral neck angle, humeral centering on the glenoid, and postoperative restoration of the anatomic center of rotation. Final postoperative radiographs were assessed for evidence of stress shielding. ResultsForty-eight patients had a stemmed humeral prosthesis, and 109 patients had a stemless prosthesis. Patient-determined outcomes were available from 2 years postoperatively in 99.4%. Both groups had significant improvements in all patient-reported outcomes and range-of-motion metrics, but there were no differences between the stemless and stemmed groups in these outcomes. The prosthetic humeral head of the stemmed components was more likely to extend further superior to the humeral osseous margin than that of the stemless group (2.0 ± 2.4 vs. 0.8 ± 1.4 mm; P = .0004). The stemless group had a smaller postoperative deviation from the anatomic center of rotation than the stemmed group (2.5 ± 1.9 vs. 3.2 ± 2.1 mm; P = .04). The humeral neck angle was comparable between the stemmed group and the stemless group (133 ± 7° vs. 131 ± 8°; P = .06). There was similar mean deviation of humeral head centering on the glenoid prosthesis between the stemmed and stemless groups (1.9 ± 1.8 vs. 1.6 ± 1.7 mm; P = .20). There was evidence of stress shielding in 10 patients (21%) with a stemmed prosthesis and in no patients with a stemless prosthesis at 1-year follow-up (P < .0001). ConclusionsThere were no differences in patient-determined outcomes between the groups at 2-year follow-up. Restoration of proximal humeral anatomy was either better or equivalent with the stemless prosthesis compared to the stemmed one. Radiographic evidence of stress shielding was found in the stemmed prosthesis but not in the stemless prosthesis at 1-year follow-up.

Short hip stem for THA in avascular necrosis of the femoral head

Osteonecrosis of the femoral head or avascular necrosis of the femoral head (HKN) is acomplex disease that, without treatment, leads to infraction of the femoral head in most cases. In these cases, only replacement of the hip joint will help, although there is no clear recommendation of an arthroplasty type. In the last two decades, the treatment of primary and secondary coxarthrosis with short-shaft prostheses with different anchoring philosophies has increased. Since short-shaft fitting is apossible option especially in younger patients, the question arises about possible fittings of advanced HKN with these stem types, especially with metaphyseal anchorage. The aim of this study was to review the existing literature on the results of short stem prosthesis in HKN and to present the advantages and disadvantages of short stem prosthesis in osteonecrosis of the femoral head. This review analyzes the existing studies on short stem arthroplasty for HKN. Only a few studies exist that have analyzed clinical and radiologic outcomes of short stem replacement in HKN. The existing short- and medium-term results show mostly good outcomes. However, it is difficult to draw ageneral conclusion due to differences in stem design and fixation. Short stems with primary diaphyseal fixation do not show an increased risk of failed osseointegration or loosening. Constructions with primary metaphyseal fixation should undergo MRI to rule out the possibility of necrosis extending beyond the femoral neck.

Twenty-year results of a neck-preserving short-stem prosthesis in primary total hip arthroplasty.

The use of short-stemmed femoral components with preservation of the femoral neck has been advocated for younger and more active patients undergoing joint replacement. This study reports the long-term outcomes of the Collum Femoris-Preserving (CFP) prosthesis on a previous report. Between January 1999 and December 2000, a total of 149 patients underwent total hip arthroplasty procedure using the CFP stem in a single institution. At latest follow-up, 79 patients were available and were included in this study. The mean age of the cohort was 73.4 (range, 44-92years) with a mean follow-up of 20.7years (range 20-21). The average age was 52.1years at index procedure (range, 21-71years). The Kaplan-Meier survivorship free from revision for any cause at 5, 10 and 20years was 93.2% (87.8-96.3%), 93.2% (87.8-96.3%) and 83.0% (75.7-88.3%), respectively. At 20years follow-up, the revision for any cause occurred in 26.6% (21 of 79) of patients. The most common causes for revision surgery were aseptic loosening, dislocation, and polyethylene wear with 6.3% (5 out of 79), respectively. Periprosthetic fracture occurred in four patients (5.1%) followed by periprosthetic joint infection in two patients (2.5%). Revision surgery of the femoral stem was required in four patients (5.1%). There was a statistically significant improvement of the Harris Hip Scores from 53 to 83.7 (range 56-91). The long-term outcomes of the CFP stem are excellent, demonstrating a low rate of aseptic loosening with an excellent survivorship within 2decades.

Midterm clinical outcome of uncemented short-stem reversed shoulder arthroplasty.

While the incidence of reverse total shoulder arthroplasty (rTSA) is increasing constantly, newer implants with designs other than the classic Grammont geometry are gaining importance. More anatomic inclination angles and lateralization are supposed to have a positive impact on clinical results and complication rates. Presentation of midterm results therefore is important to support these assumptions. The aim of this study was to report the midterm clinical outcome of primary rTSA with an uncemented humeral short-stem prosthesis (USSP) with a humeral inclination angle of 145° and the analysis of different variables on the outcome. This is a retrospective study of all patients with primary rTSA using an USSP and a combined humeral inclination angle of 145° (Ascend™ flex, Stryker) with a minimum clinical follow-up of 2years. The implant combines a 132.5° inclination for the humeral stem with an additional 12.5° for the polyethylene inlay. Primary outcomes were patient-reported outcome measures: ASES score, simple shoulder test (SST) and subjective shoulder value (SSV). Secondary outcomes were complication and revision rates. We analyzed different variables: preoperatively gender, age, indication for surgery and status of rotator cuff. Also, the glenoid morphology was classified according to Walch and a proximal humerus cortical bone thickness measurement (CBT avg) of 6mm was used as a threshold for osteoporosis. Postoperatively, we analyzed different radiologic parameters: filling ratio, distalization and lateralization angles according to Boutsiadis. A total of 84 out of 99 (85%) patients with a mean FU of 46.7months (range 24-80months) could be included: 62 women and 22 men with a mean age of 74.7years. Mean ASES score significantly increased from 47 preoperatively to 85.8 at the last follow-up (p = 0.001). The postoperative SST reached an average of 65.3 and the mean SSV was 83%. None of the variable parameters analyzed could be identified as a risk factor for a lower outcome defined as a SSV < 70. Three patients (3.6%) had a complication: one incomplete lower plexus lesion, one dislocation and one major hematoma. Surgical revision was needed in two cases (2.4%). The midterm clinical outcome of primary reverse total shoulder arthroplasty (rTSA) with an uncemented humeral short stem and a humeral inclination angle of 145° showed good-to-excellent results with a low complication and revision rate independent from a wide range of pre- and postoperative variables. PROMs are comparable to those reported for anatomic TSA with a low complication rate, different to historical studies especially with the Grammont design. Treatment study, Level IV.

Minimally Invasive Anterolateral Approach Total Hip Arthroplasty Using Bone Preserving Short Femoral Stem: Intermediate Term Clinical and Radiological Results

Aim: The objective of this study was to evaluate the intermediate term clinical and radiological results of a Bone preserving short stem hip implant being operated through a minimally invasive anterolateral hip approach. Methods: In 20 consecutive patients suffering from osteoarthritis with 25 affected hip joints (five cases were bilateral), the clinical and radiological results of 25 hip arthroplasties performed in one hospital between October 2009 and May 2014 through a minimally invasive anterolateral approach using a cementless short stem prosthesis type Aida and a cementless cup type Ecofit with a ceramic-on-ceramic pairing were evaluated prospectively. The median age of patients at time of surgery was 60 years (range, 42-71 years), 15 male (4 were bilateral) and 5 female patients (one was bilateral) were included in the study. The median clinical follow up was 30 months (range, 2-88 months) and the median radiological follow up was 30 months (range, 2-88 months). Results: Harris Hip Score improved from a median preoperative value of 53 to a median postoperative value of 96 (range, 73-100) at follow up. 22 hips (88%) showed an excellent postoperative Harris Hip Score, 2 hips (8%) a good postoperative Harris Hip Score and one hip (4%) a fair postoperative Harris Hip Score. Only two patients complained of postoperative thigh pain. Regarding patient satisfaction, 15 patients (60%) were very satisfied, 10 patients (40%) were satisfied. None was unsatisfied. Radiological analysis showed that 19 stems (76%) were with stable bony ingrowth, two cases (8%) showed stable fibrous ingrowth. Four cases need further follow up for proper evaluation of stem fixation. Conclusion: The intermediate term survival of the Aida short stem hip implant being operated through a minimally invasive anterolateral hip approach is very promising and achieving the goals of a standard hip arthroplasty.

Bone Preservation in Total Hip Arthroplasty.

Preserving bone stock in younger and more active patients after total hip arthroplasty (THA) is important for future revision. Newer prosthesis designs, including short femoral stems and isoelastic acetabular cups, are likely to preserve more bone stock. However, long-term follow-up studies on bone remodeling after short-stem THA with an isoelastic monoblock acetabular cup are few. Therefore, we evaluated bone preservation after THA using these prostheses at a 5-year follow-up. This prospective observational study is a 5-year follow-up of our previously reported 2-year observational study on the same cohort of patients. We included 45 patients with primary osteoarthritis treated with a calcar-guided femoral short-stem prosthesis and a monoblock press-fit acetabular cup. We evaluated bone mineral density (BMD) around the prostheses using dual-energy X-ray absorptiometry and reported functional outcomes preoperatively and at 3, 12, 24, and 60 months postoperatively. All complications were recorded. At the final follow-up, the BMD was comparable with that at 24 months in Gruen zones 3, 4, 5, 6, and 7, whereas it significantly differed in Gruen zones 1 (P < .0001) and 2 (P < .004). On the acetabular side, the BMD leveled off similarly in all DeLee and Charnley zones between 24 and 60 months (P > .05). Moreover, all measured clinical outcomes significantly improved (P < .001). One perioperative dislocation was reported. Patients undergoing THA with a calcar-guided femoral short-stem prosthesis and a monoblock acetabular cup can expect preservation of bone stock over a longer follow-up with excellent clinical outcomes and few complications.