Short-stem Prosthesis Research Articles

Complications after radial head arthroplasty: a comparison between short-stemmed bipolar and monopolar long-stemmed osteointegrative rigidly fixed prostheses

To date, only a few studies have compared radial head prostheses (RHP) and their different anchoring principles. The aim of this study was to characterize concomitant injuries, necessary adjuvant procedures, complications, and radiological findings after implantation of two different types of RHP. Sixty-six patients with radial head fractures were treated with MoPyC (Tornier/France, 50mm stem, monopolar) or SBI rHead prostheses (Small Bone Innovations/USA, 22-mm stem, bipolar) and followed up over 42months (16-64months). Primary objective was the detection of different loosening and explantation rates. In addition to the revision rate and the reasons for revision, we also used radiological findings to assess the dynamics of lysis phenomena. Thirty-five patients (mean age 48years; 22-73years) were treated with the MoPyC, and 31 patients (mean age 47years, 19-69years) with the rHead prosthesis. Of these, 98% had a Mason 3 or 4 type of radial head fracture, and 94% showed concomitant injuries, which were addressed in 89% of cases by adjuvant procedures. The surgical revision rate was 20% (rHead 23%; MoPyC 18%). Significantly more of the rHead prostheses had to be explanted compared to MoPyC prostheses because of painful loosening (16% vs. 3%; p= 0.029). Predictors of subsequent loosening were significant radiolucent lines in the RHP over the first six months and an increase in width by two and a half times within the first 50days after implantation. Complex radial head fractures are frequent and difficult to treat. The monopolar long-stemmed prosthesis showed significantly lower rates of painful loosening and explanation rates than the bipolar short-stemmed prosthesis.

Short-term results of a second generation anatomic short-stem shoulder prosthesis in primary osteoarthritis.

The aim of the study was to evaluate the short-term clinical results of anatomic total shoulder arthroplasty with a short-stem prosthesis in primary osteoarthritis. 65 shoulders with a mean age of 70years (range 47-85years) were available for minimum follow-up of 24months. Clinical outcome was determined by range of motion, Constant score (CS) age and sex-adjusted Constant score (CS%), and subjective shoulder value (SSV). The influence of six different factors (high bone adaptations, age > 65 years, female gender, dominant side, atrophy of the supraspinatus tendon ≥ grade 2, glenoid type B2/B3) on the clinical outcome was assessed. At mean follow-up of 37months (range 24-58months), the CS improved from 36 ± 8 to 75 ± 12 (p < 0.001). The shoulder flexion (100° ± 21° to 159° ± 19°) as well as the external rotation (3° ± 11° to 43° ± 18°) improved significantly (p < 0.001). Three complications were noted (transient neuropraxia of the radial nerve, subjective instability, hematoma with superficial wound infection) leading to one revision surgery (wound debridement). No stem loosening was observed. High bone adaptation was present in 19 out of 65 shoulders (29%). The clinical outcome was not influenced by high bone adaptations (p ≥ 0.095). Age > 65years (n = 44) and female gender (n = 38) were associated with worse clinical outcome (p ≤ 0.043). In the short term, the clinical results of this anatomical short-stem shoulder prosthesis are encouraging. A low prevalence of high bone adaptations was found without any influence on the clinical outcome and stem loosening was not observed.

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...

Mid-term migration analysis of a femoral short-stem prosthesis: a five-year EBRA-FCA-study.

The objective of this study was to evaluate the mid-term migration pattern of a femoral short stem. Implant migration of 73 femoral short-stems was assessed by Ein-Bild-Roentgen-Analysis Femoral-Component-Analysis (EBRA-FCA) 5 years after surgery. Migration pattern of the whole group was analysed and compared to the migration pattern of implants "at risk" with a subsidence of more than 1.5 mm 2 years postoperative. Mean axial subsidence was 1.1 mm (-5.0 mm to 1.5 mm) after 60 months. There was a statistical significant axial migration until 2 years postoperative with settling thereafter. 2 years after surgery 18 of 73 Implants were classified "at risk." Nevertheless, all stems showed secondary stabilisation in the following period with no implant failure neither in the group of implants with early stabilisation nor the group with extensive early onset migration. In summary, even in the group of stems with more pronounced early subsidence, delayed settling occurred in all cases. The determination of a threshold of critical early femoral short stem subsidence is necessary because of the differing migration pattern described in this study with delayed settling of the Fitmore stem 2 years postoperatively compared to early settling within the first postoperative year described for conventional stems.

Bone-preserving total hip arthroplasty in avascular necrosis of the hip—a matched-pairs analysis

Short-stem hip arthroplasty has the potential advantage of femoral bone stock preservation, especially in view of the expected revisions in the often relatively young patients. Despite short-stem hip prosthesis are increasingly used for total hip arthroplasty, there are no sufficient mid- and long-term results especially for patients with avascular femoral head osteonecrosis. The present study investigates mid-term functional results as well as the revision rate following implantation of a short-stem prosthesis. In the period 06/2005 until 12/2013, a total of 351 short-stem hip prostheses were implanted. The study included 331 complete data sets. A retrospective analysis was performed using the Oxford Hip Score. All revisions were registered. In a total of 331 prostheses, the Oxford Hip Score was "excellent" in 66.2%, "good" in 12.7%, "fair" in 13.0%, and "poor" in 8.2% with a mean follow-up of 57.4months (SD ± 29.8; range 24-115). In 26 cases, aseptic osteonecrosis of the hip was the indication (7.9%). The Oxford Hip Score was "excellent" in 66.7%, "good" in 0.0%, "fair" in 20.8%, and "poor" in 12.5%. The cumulated five year survival rate was 96.7%. In mid-term observation, the Metha® short-stem prosthesis shows no disadvantage in functional outcome and in survival time compared to a standard hip stem. Providing a correct indication, the Metha® short stem is a valuable option in total hip arthroplasty for younger patients with avascular osteonecrosis of the femoral head. Evaluation has shown no significant differences between aseptic osteonecrosis and other indications.

Hip prostheses in young adults. Surface prostheses and short-stem prostheses

The poor results obtained in young patients when using a conventional prosthesis led to the resurgence of hip resurfacing to find less invasive implants for the bone. Young patients present a demand for additional activity, which makes them a serious challenge for the survival of implants. In addition, new information technologies contribute decisively to the preference for non-cemented prostheses. Maintaining quality of life, preserving the bone and soft tissues, as well as achieving a very stable implant, are the goals of every hip orthopaedic surgeon for these patients. The results in research point to the use of smaller prostheses, which use the metaphyseal zone more and less the diaphyseal zone, and hence the large number of the abovementioned short stem prostheses. Both models are principally indicated in the young adult. Their revision should be a more simple operation, but this is only true for hip resurfacing, not for short stems.

Survival Rate of Short-Stem Hip Prostheses: A Comparative Analysis of Clinical Studies and National Arthroplasty Registers

BackgroundThe primary aim was to evaluate the outcome of short-stem hip prostheses in terms of overall revision rates. Data were taken from published literature and national arthroplasty registers. The second study aim was to evaluate a potentially superior outcome of dependent compared to independent clinical studies. MethodsAll clinical studies on short-stem hip prostheses between 2006 and 2016 were reviewed and evaluated with a special interest on revision rates. Revision rate was calculated as “revision per 100 component years.” Short stems were divided into femoral neck retaining (NR), neck sparing (NS), and neck harming (NH) prostheses. Published literature was further classified into dependent and independent studies, and data were compared to the Australian National Arthroplasty Register. ResultsFifty-two studies with 56 cohorts met the inclusion criteria and were therefore included in our study. All clinical studies showed a median revision rate of 4.8% after 10 years. NS and NH stems performed equally, whereas neck retaining prostheses were significantly inferior. Independent showed higher revision rates compared to dependent data without being statistically significant. The Australian register revealed a revision rate of 6.6% after one decade. ConclusionSimilar low revision rates for NS and NH short-stem prostheses were found in the included data. Dependent studies seem not to be biased with regard to the longevity of short-stem hip replacement. Longer follow-up periods in clinical studies and more detailed information in arthroplasty registers would be desirable for future studies.

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

BackgroundThe resultant hip force causes a varus torque which must be compensated by a shear force couple depending on the stem alignment of the prosthesis. Since the prosthesis is substantially less flexible than the bone, the interior of the femur is stiffened over the entire prosthesis length. The present study thus aims at analyzing short-stem prostheses for its elastic bending characteristics, considering inappropriate valgus alignment of the prosthetic stem. MethodsFive short stem prostheses were implanted each in synthetic femora in a standardized manner – in neutral and valgus stem alignments. Bending movements were recorded applying a tilting torque MX of ±3.5 Nm in medio-lateral direction. Variance analyses and Friedman tests were used. A P-value <.05 was considered statistically significant. FindingsBending movements b1-b6 showed significant differences (P < .05). It could be shown that different stem alignments (P < .05) and different measuring points had a highly significant influence (P < .001) on the relative movements. Compared to the AIDA®, the MiniHip™ as well as the Metha® stiffened the femur to a higher degree (P < .001). InterpretationRegarding the elastic bending behavior we see a relevant influence of the stems´ design. We conclude that the short-stem principle does not necessarily require the shortest possible prosthesis but rather a long and thin extending stem tip to optimize the lever ratios, ensuring a more physiological bending behavior of the femur. In addition, without sufficient anchoring of the prosthesis, the valgus stem alignment could favor tilting of the implant and should therefore be avoided.

No effect of conventional vs. minimally invasive surgical approach on clinical outcome and migration of a short stem total hip prosthesis at 2-year follow-up: A randomized controlled study

BackgroundShort stem hip prostheses have become a viable alternative for the treatment of hip osteoarthritis. In combination with minimally invasive surgery, short stem hip prostheses offer potential advantages of reduced surrounding tissue damage and faster rehabilitation. However, the limited perioperative visibility of these minimally invasive techniques may lead to reduced primary stability compared to conventional techniques. We hypothesized: a) increased migration of the minimally invasive group due to reduced primary stability and b) increased clinical scores of the minimally invasive group. MethodsSixty total hip arthroplasty patients were randomly assigned to undergo minimally invasive anterolateral modified Watson-Jones or conventional Hardinge surgery. All patients were treated with a Metha short stem prosthesis. Roentgen stereophotogrammetry and clinical scores were calculated after surgery and at 3, 6, 12, and 24months postoperatively. FindingsNo statistically significant differences in implant migration and clinical scores were observed between the minimally invasive and conventional groups at any follow-up point. The largest average resultant migrations were 1.22 (SD 1.31) mm (conventional) and 1.18 (SD 1.18) mm (minimally invasive) after 24months. The mean Harris Hip Score score improved from 54 (SD 10, conventional) and 52 (SD 13, minimally invasive) preoperatively to 97 (SD 5, both groups) after 24months. InterpretationOverall, the differences in implant migration and clinical scores between the minimally invasive and conventional surgery groups were marginal and not clinically relevant. The data from this study suggest that good results can be expected from both the investigated approaches.

Las prótesis de cadera en el adulto joven. Prótesis de superficie y prótesis de vástago corto

The poor results obtained in young patients when using a conventional prosthesis led to the resurgence of hip resurfacing to find less invasive implants for the bone. Young patients present a demand for additional activity, which makes them a serious challenge for the survival of implants. In addition, new information technologies contribute decisively to the preference for non-cemented prostheses. Maintaining quality of life, preserving the bone and soft tissues, as well as achieving a very stable implant, are the goals of every hip orthopaedic surgeon for these patients. The results in research point to the use of smaller prostheses, which use the metaphyseal zone more and less the diaphyseal zone, and hence the large number of the abovementioned short stem prostheses. Both models are principally indicated in the young adult. Their revision should be a more simple operation, but this is only true for hip resurfacing, not for short stems.

Mid-term outcomes of 77 modular radial head prostheses.

Radial head arthroplasty (RHA) may be used in the treatment of non-reconstructable radial head fractures. The aim of this study was to evaluate the mid-term clinical and radiographic results of RHA. Between 2002 and 2014, 77 RHAs were implanted in 54 men and 23 women with either acute injuries (54) or with traumatic sequelae (23) of a fracture of the radial head. Four designs of RHA were used, including the Guepar (Small Bone Innovations (SBi)/Stryker; 36), Evolutive (Aston Medical; 24), rHead RECON (SBi/Stryker; ten) or rHead STANDARD (SBi/Stryker; 7) prostheses. The mean follow-up was 74.0 months (standard deviation (sd) 38.6; 24 to 141). The indication for further surgery, range of movement, mean Mayo Elbow Performance (MEP) score, quick Disabilities of the Arm, Shoulder and Hand (quickDASH) score, osteolysis and positioning of the implant were also assessed according to the design, and acute or delayed use. The mean MEP and quickDASH scores were 90.2 (sd 14; 45 to 100), and 14.0 points (sd 12; 1.2 to 52.5), respectively. There were no significant differences between RHA performed in acute or delayed fashion. There were 30 re-operations (19 with, and 11 without removal of the implant) during the first three post-operative years. Painful loosening was the primary indication for removal in 14 patients. Short-stemmed prostheses (16 mm to 22 mm in length) were also associated with an increased risk of painful loosening (odds ratio 3.54 (1.02 to 12.2), p = 0.045). Radiocapitellar instability was the primary indication for re-operation with retention of the implant (5). The overall survival of the RHA, free from re-operation, was 60.8% (sd 5.7%) at ten years. Bipolar and press-fit RHA gives unsatisfactory mid-term outcomes in the treatment of acute fractures of the radial head or their sequelae. The outcome may vary according to the design of the implant. The rate of re-operation during the first three years is predictive of the long-term survival in tight-fitting RHAs. Cite this article: Bone Joint J 2017;99-B1197-1203.

Bone preserving level of osteotomy in short-stem total hip arthroplasty does not influence stress shielding dimensions \u2013 a comparing finite elements analysis

BackgroundThe main objective of every new development in total hip arthroplasty (THA) is the longest possible survival of the implant. Periprosthetic stress shielding is a scientifically proven phenomenon which leads to inadvertent bone loss. So far, many studies have analysed whether implanting different hip stem prostheses result in significant preservation of bone stock. The aim of this preclinical study was to investigate design-depended differences of the stress shielding effect after implantation of a selection of short-stem THA-prostheses that are currently available.MethodsBased on computerised tomography (CT), a finite elements (FE) model was generated and a virtual THA was performed with different stem designs of the implant. Stems were chosen by osteotomy level at the femoral neck (collum, partial collum, trochanter sparing, trochanter harming). Analyses were performed with previously validated FE models to identify changes in the strain energy density (SED).ResultsIn the trochanteric region, only the collum-type stem demonstrated a biomechanical behaviour similar to the native femur. In contrast, no difference in biomechanical behaviour was found between partial collum, trochanter harming and trochanter sparing models. All of the short stem-prostheses showed lower stress-shielding than a standard stem.ConclusionBased on the results of this study, we cannot confirm that the design of current short stem THA-implants leads to a different stress shielding effect with regard to the level of osteotomy. Somehow unexpected, we found a bone stock protection in metadiaphyseal bone by simulating a more distal approach for osteotomy. Further clinical and biomechanical research including long-term results is needed to understand the influence of short-stem THA on bone remodelling and to find the optimal stem-design for a reduction of the stress shielding effect.

Finite Element Analysis of porously punched prosthetic short stem virtually designed for simulative uncemented Hip Arthroplasty

BackgroundThere is no universal hip implant suitably fills all femoral types, whether prostheses of porous short-stem suitable for Hip Arthroplasty is to be measured scientifically.MethodsTen specimens of femurs scanned by CT were input onto Mimics to rebuild 3D models; their *stl format dataset were imported into Geomagic-Studio for simulative osteotomy; the generated *.igs dataset were interacted by UG to fit solid models; the prosthesis were obtained by the same way from patients, and bored by punching bears designed by Pro-E virtually; cements between femora and prosthesis were extracted by deleting prosthesis; in HyperMesh, all compartments were assembled onto four artificial joint style as: (a) cemented long-stem prosthesis; (b) porous long-stem prosthesis; (c) cemented short-stem prosthesis; (d) porous short-stem prosthesis. Then, these numerical models of Finite Element Analysis were exported to AnSys for numerical solution.ResultsObserved whatever from femur or prosthesis or combinational femora-prostheses, “Kruskal-Wallis” value p > 0.05 demonstrates that displacement of (d) ≈ (a) ≈ (b) ≈ (c) shows nothing different significantly by comparison with 600 N load. If stresses are tested upon prosthesis, (d) ≈ (a) ≈ (b) ≈ (c) is also displayed; if upon femora, (d) ≈ (a) ≈ (b) < (c) is suggested; if upon integral joint, (d) ≈ (a) < (b) < (c) is presented.ConclusionsMechanically, these four sorts of artificial joint replacement are stabilized in quantity. Cemented short-stem prostheses present the biggest stress, while porous short-stem & cemented long-stem designs are equivalently better than porous long-stem prostheses and alternatives for femoral-head replacement. The preferred design of those two depends on clinical conditions. The cemented long-stem is favorable for inactive elders with osteoporosis, and porously punched cementless short-stem design is suitable for patients with osteoporosis, while the porously punched cementless short-stem is favorable for those with a cement allergy. Clinically, the strength of this study is to enable preoperative strategy to provide acute correction and decrease procedure time.

Effect of periprosthetic fracture on hip function after femoral neck-preserving total hip arthroplasty: study protocol for a prospective, single-center, self-controlled trial with 2-year follow-up

Background: Total hip replacement with a collum femoris preserving (CFP) short stem prosthesis can reportedly reduce postoperative complications and preserve maximum bone tissue for long-term revision. However, CFP replacement has a relatively high risk of intraoperative periprosthetic fractures that can seriously harm hip function recovery. Therefore, this study aims to analyze risk factors for periprosthetic fractures and develop preventive measures to reduce postoperative complications. Methods/Design: A prospective, single-center, self-controlled, open-label study with 2-year follow-up will be carried out at the Department of Orthopedics, Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, China. We will analyze data from 25 patients who undergo total hip replacement with the CFP prosthesis. Primary outcome measure is Harris hip score preoperatively and 6, 12, and 24 months postoperatively. Secondary outcome measures include fracture severity as assessed by periprosthetic fracture classification according to the American Academy of Orthopaedic Surgeons guidelines, and bone healing as assessed by CT and radiographic findings preoperatively and 6, 12, and 24 months postoperatively, including parameters of the proximal and mesal medullary cavity of the fractured femur (width of the medullary cavity at the point 20 mm above the midpoint of the small trochanter, at the midpoint of the small trochanter, at the point 20 mm below the midpoint of the small trochanter, and at the fracture line; width of the corresponding prostheses), intertrochanteric width, femoral neck-stem angle, femoral neck anteversion, femoral neck length, ratio of the distal end of the prosthesis to the medullary space, and height of the femoral calcar. Other outcome measures are multiple logistic regression analysis results of risk factors for periprosthetic fracture during hip replacement, and the incidence of adverse events within 24 months postoperatively. Discussion: This study will be expected to provide references for reducing the incidence of periprosthetic fracture during hip replacement with the CFP prosthesis. Trial registration: ClinicalTrials.gov identifier: NCT02981823. Ethics: Approved by the Ethics Committee of the Third Hospital of Hebei Medical University, China (approval number: KE2016-011-1), the study protocol will be performed in accordance with the guidelines of the Declaration of Helsinki, formulated by the World Medical Association. Informed consent: Written informed consent will be obtained from all participants prior to the trial.

First experiences with the Fitmore® hip stem: Early results of the 16-month monitoring.

Fitmore® hip stem belongs to the group of short stem prostheses with the metaphysar stabilization, with its shape and form that protects the bone mass in the greater trochanter region and the distal part of the femur. The aim of this paper was to present the early postoperative results in patients with implanted Fitmore® hip stem and point out some of the advantages. A series of 10 patients with implanted Fitmore® hip stem, was included in this study. The average age of the patients was 54.5 (48–65) years. There were 5 women and 5 men. The total monitoring time was 16 months. To rate the condition of the hip joint we used The Western Ontario and Mc Master Universities Arthritis Index (WOMAC) score. We also monitored the degree of hip pain, hip flexion, heterotopic ossification and indentation in the stem of the prosthesis. After 12 months of monitoring 9 (90%) of the patients had no pain in the thigh region, and only 1 (10%) experienced mild pain. The hip flexion rose from the average 89° to postoperative 114°. WOMAC score rose as well, from 49 to 94 average points. Indentation in the stem was registered 3 months after the operation in 2 (20%) of the patients – in one of the patients the indentation was 3 mm and in the other patient 5 mm. After the 16-month monitoring, the results were excellent. The monitoring period was short though it should be continued and the results should be presented after 5 and then after 10 years. Early results of the implantation Fitmore stem showed good bone ingrowth with excellent functional result.

Porous Femoral Fixation in Total Hip Arthroplasty with Short Anatomical Stem: Radiographic Evaluation.

BackgroundHip prostheses with short anatomical stems were designed for metaphyseal fixation and to spare bone stock. We present a study of a short anatomical femoral stem used in all age groups of patients with Dorr A and B type of femora.MethodsWe reviewed radiographs of 85 hips in 74 patients who had a cementless total hip arthroplasty with a short anatomical 80 mm femoral stem designed to achieve pure metaphyseal fixation. A ream-only technique was used for femoral canal preparation in all patients. At each follow-up, radiological evaluation was performed for stem alignment, proximal metaphyseal fill, subsidence, status of biological fixation of the femoral stem, heterotrophic ossification, radiolucency, osteolysis, and limb length discrepancy of the stem. Acetabular components were evaluated for positioning, acetabular bone coverage, and radiolucent and osteolytic lesions.ResultsThe final mean alignment of femoral stem was 2° valgus. The average intramedullary fill by the stem at the proximal level of the lesser trochanter was 93% in the coronal plane and 88% in the sagittal plane. No components were considered to be undersized. Thirteen hips (15.2%) presented radiolucent lines (10 hips < 1 mm in width and 3 hips [3.5%] 2 mm in width) and 100% of them were not progressive with respect to the last follow-up radiograph. All of the stems had excellent fixation by demonstrating bone ingrowth at the latest follow-up. At the last follow-up, heterotopic ossification was noted in 5 hips. The mean preoperative limb length discrepancy was 9.3 mm and the mean postoperative discrepancy was 3.8 mm. The mean acetabular component angle of the 85 components was 41.2° with a mean anteversion of 22.1°. At the last follow-up, there were no revisions of the femoral component. One patient, 25 months after the index operation, required an acetabular component revision because of recurrent hip dislocation. There were no radiological signs of loosening in any of the short-stem prostheses at the last examination.ConclusionsThe short, metaphyseal-fitting anatomic cementless femoral stem provided stable fixation without relying on diaphyseal fixation.

Do short-stemmed prostheses used for radial head arthroplasties have an increased risk of implant loosening?

Introduction La prothese de tete radiale (PTR) est actuellement indiquee dans les fractures comminutives non osteosynthesables de tete radiale. Les resultats rapportes a moyen et long terme sont satisfaisants avec les protheses metalliques modulaires a cupule mobile. Le taux de descellement reste non negligeable et variable selon les implants. L’hypothese emise etait que la taille de la tige prothetique pouvait influencer le taux de descellement. Materiel et methodes Entre 2002 et 2014, une prothese de tete radiale a ete mise en place chez 43 hommes et 21 femmes d’âge moyen 52 ans (± 16). L’indication comprenait 44 fractures recentes pour 20 sequelles. Il s’agissait de 56 fractures type Mason III, 2 de type Mason II, et 6 fractures cervicales vraies. Les protheses implantees comprenaient 31 protheses Guepar (tige longue 30 mm), 18 Evolutive TM Aston Medical (tige longue 30 mm), 15 protheses SBI comprenant 9 rHead Recon et 6 rHead Standard (tige courte 16–22 mm). Au recul minimum de 24 mois, une analyse radiographique a permis d’analyser le positionnement des protheses, la presence d’une osteolyse periprothetique, et l’existence de signe de descellement. L’evaluation clinique permettait d’evaluer les amplitudes articulaires, la force en flexion–extension, le MEPS, et le score DASH. Resultats Au recul moyen de 65 mois, le taux de re-intervention pour descellement etait plus eleve pour les tiges courtes par rapport aux tiges longues (6 vs 9, p p p p p Conclusion Dans cette etude, si les resultats cliniques etaient identiques, quel que soit le type d’implant, le taux de descellement des implants a tige courte etait nettement superieur a celui des implants a tige plus longue.

Short-stem prostheses in primary total hip arthroplasty: A meta-analysis of randomized controlled trials.

Background:Short-stem (SS) prostheses require less resection of the femoral neck, produce a more physiological load pattern in the proximal femur, reduce stress shielding, and aid bone conservation and are, therefore, beneficial for young patients. Conventional cementless implants in total hip arthroplasty (THA) have shown excellent clinical results; however, it is unclear whether SS prostheses can obtain the same clinical and radiological outcomes. We conducted a meta-analysis of randomized controlled trials (RCTs) to evaluate whether SS prostheses are superior to conventional implants after primary THA.Methods:We reviewed the literature published up to June 2016 from PubMed, Web of Science, and the Cochrane Library to find relevant RCTs comparing SSs and conventional stems in primary THA. Quality assessment was performed by 2 independent reviewers. The RevMan 5.3 software program of the Cochrane Collaboration was used to analyze the data. Random- or fixed-effect models were used to calculate standardized mean differences (SMDs) and 95% confidence intervals (CIs) for each comparison.Results:Six RCTs involving 552 patients with 572 hips were identified. Strong evidence indicated that SS prostheses were more effective for reducing thigh pain than conventional implants (I 2 = 46%, P = 0.002; risk ratio [RR], 95% CI 0.15, 0.04–0.49). However, there were no significant differences between the 2 groups in Harris Hip Scores (I 2 = 0%, P = 0.84; SMD, 95% CI 0.02, −0.15–0.18), Western Ontario and McMaster Universities Osteoarthritis Index Scores (I 2 = 0%, P = 0.35; SMD, 95% CI 0.09, −0.10–0.27), femoral offset of stem (I 2 = 0%, P = 0.57; SMD, 95% CI 0.06, −0.16–0.29), and leg-length discrepancy (I 2 = 79%, P = 0.88; SMD, 95% CI 0.04, −0.44–0.51).Conclusion:SS prostheses achieve the same clinical and radiological outcomes as conventional implants, and were superior in terms of reducing thigh pain. But whether the postoperative thigh pain applied in 2nd-generation cementless prosthesis still needs further large-scale multicenter studies with longer follow-up to confirm.

Periprosthetic bone density changes after MiniHipTM cementless femoral short stem: one-year results of dual-energy X-ray absorptiometry study.

Introduction: The purpose of the current study was to investigate the reaction of the femur to the implantation of the MiniHipTM in terms of: (1) bone density change during one year; (2) correlations between stem length, CCD (caput-collum-diaphyseal), femoral offset, T-value, and bone density; (3) other co-variables that influence the change of bone density. Patients and methods: MiniHipTM implant was performed for 62 patients. The age range of the patients who underwent treatment was 25–78 years. Periprothestic bone density was determined within two weeks postoperatively, after three, six, and twelve months utilizing the DEXA scan. Results: The highest change was observed in the first three months post-implantation, while significant decrease in density was recorded at proximal Gruen zones 1, 2, and 7, and at distal Gruen zone 4. The decrease in density reached a plateau between the third and sixth months after operation. Afterwards, bone density recovered up to the 12th postoperative month. The correlation analysis showed significant difference between Gruen zone 1 and stem size and CCD. The same significant trend was not reached for Gruen zone 7. Femoral offset showed no correlation. Covariance analysis was unable to establish connection of the results with diagnosis, pairings, or gender. Discussion: MiniHipTM densitometric results are promising and comparable to good results of the other representatives of the femoral neck partially-sustaining short stem prostheses with a lower proximal bone density reduction. Periprosthetic bone resorption is a multifactorial process where stem size, CCD angle, and patient-specific variables such as T-value have an impact on the periprosthetic bone remodeling. In particular, this applies to Gruen zone 1.

Bone remodelling after femoral short stem implantation in total hip arthroplasty: 1-year results from a randomized DEXA study.

Short stem prostheses have been developed to preserve proximal femoral bone stock. This prospective, randomized study compared periprosthetic bone remodelling following short and straight stem implantation 1 year after surgery. One hundred and forty-four consecutive patients undergoing total hip arthroplasty were randomized to either a Fitmore short or a cementless straight stem (both Zimmer, Winterthur, Switzerland). Periprosthetic bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry performed the day before surgery and at 7 days, 3 months and 1 year postoperatively. Furthermore, the HHS and the WOMAC were obtained. One hundred and thirty-eight patients completed 1-year follow-up. Periprosthetic BMD changes at 1 year were most pronounced in the proximal medial region of interest (ROI) 7 with -17.2% after short stem and -16.7% after straight implantation (p = 0.67). However, there was significantly less BMD reduction in ROI 6 following short (-4.7%) versus straight stem (-10.8%) implantation (p = 0.01). There were no significant differences between the two groups in terms of the HHS and the WOMAC either before or after surgery. One year after surgery, both stems showed an implant-specific periprosthetic bone remodelling. Nevertheless, proximal load transfer was more pronounced after short stem implantation than with a straight stem.