Early Subsidence Research Articles

Mid-term subsidence and periprosthetic radiolucency of the AMIStem: a 5-year EBRA-FCA analysis

BackgroundThere has been an evolution in cementless total hip arthroplasty (THA) with newer short stem designs aimed to preserve metaphyseal bone stock and facilitate implantation through minimally invasive approaches. While early subsidence has been correlated to aseptic loosening in conventional stems, there is a paucity of data regarding short stems. The current study aims to report on stem subsidence and mid-term clinical outcomes of a cementless, metaphyseal-anchored short femoral stem, specifically designed for the direct anterior approach (DAA).MethodsNinety-four consecutive patients (100 hips) with a minimum follow-up of 5 years following cementless THA were included in this single-center retrospective study. Subsidence was evaluated using the “Ein-Bild-Roentgen-Analyse” (EBRA). Periprosthetic radiolucency allocated to the zones of Charnley and Gruen was assessed. Additionally, demographic and implant-related factors potentially associated with increased subsidence and clinical outcomes were evaluated.ResultsAt the last follow-up, the average stem subsidence was 1.98 ± 1.20 mm, with 48% of the implants demonstrating subsidence of > 2 mm. Periprosthetic radiolucency of > 2 mm was found in 26% of the implants in zone 1 and in 9% in zone 7, respectively. Neither the amount of subsidence nor proximal periprosthetic radiolucency was associated with aseptic loosening or worse clinical outcomes.ConclusionsComparable to other proximally fixed short stem designs, the highest subsidence was observed within the first 3 months following implantation. No demographic or implant-related factors were found to have a statistically significant influence on stem subsidence. Periprosthetic radiolucency and subsidence of the AMISstem is not correlated with worse clinical outcomes at 5-year follow-up.

The Effect of Age and Activity Level on Stem Subsidence in Total Hip Arthroplasty

AbstractThe average length of hospital stay (LOS) following total hip arthroplasty (THA) is decreasing due to a variety of factors, including rapid patient mobilization. With increased early joint loading, certain populations, such as those with low systemic bone mineral density, may be at an increased risk for early stem instability. The purpose of this study was to determine whether activity level and patient age affect femoral stem stability and early subsidence. We retrospectively reviewed 821 patients who underwent primary cementless THA. Two cohorts were established based on LOS as a proxy for activity: (1) same calendar day discharge (SDD) and (2) multiple day stay (MDS). Descriptive patient characteristics as well as surgical and clinical data including surgical time, stem alignment, and Activity Measure for Post-Acute Care (AM-PAC) scores were collected. Stem subsidence was assessed by comparing immediate postoperative radiographs with follow-up radiographs taken no less than 3 months after surgery (9.79 ± 6.50 months). Our sample population consisted of 255 SDD (31%) and 566 MDS (69%) patients. Stem subsidence rate was significantly lower in the SDD than the MDS group (0.916 vs. 1.80 mm, p < 0.001). Increasing age was associated with a higher rate of stem subsidence (β = 0.823, p < 0.001). Increased LOS was also associated with increased age (odds ratio = 1.092, p < 0.001). Higher postoperative mobility determined by AM-PAC scores was not associated with shorter LOS (p = 0.630). The result of this study showed increased activity level does not increase rate of subsidence in THA patients, which supports the safety and efficacy of expedited recovery programs. Increased age was found to increase stem subsidence regardless of LOS.

Are Elevated Nicotine and Cotinine Levels Associated with Early Femoral Component Subsidence in Press-Fit, Primary Total Hip Arthroplasty?

AbstractTobacco exposure negatively affects bone mineral density and early osseointegration of surgical implants. We sought to determine if elevated nicotine and/or cotinine levels prior to primary total hip arthroplasty (THA) are associated with early femoral component subsidence. We hypothesize that tobacco users will have higher rates of readmission/reoperation and increased radiographic subsidence. We conducted an institutional review of 75 patients (average age = 52.9 years; 55% females; body mass index = 31.3) who underwent THA from April 2017 to January 2018. Immediate postoperative radiographs were compared with those obtained at 2 to 6 weeks postoperatively to determine early femoral component subsidence. Of the 75 patients, 10 (13.3%) had early radiographic femoral component subsidence ≥ 2 mm. In this group, preoperative nicotine levels were significantly elevated (7.2 vs. 1.5ng/mL; p = 0.04), whereas preoperative cotinine levels did not statistically differ (108.3 vs. 33.8 ng/mL; p = 0.45). A significantly greater magnitude of subsidence was seen in those with elevated preoperative nicotine levels compared with those with normal levels (1.7 vs. 0.5 mm; p = 0.04). The mean time to radiographic follow-up was 2.6 weeks. Surgical approach, implant type, categorical variables, and patient readmission were not associated with ≥ 2 mm of early subsidence. There was a single reoperation for periprosthetic fracture, but none was related to instability from subsidence. Early femoral component subsidence was more prevalent in patients with elevated preoperative nicotine levels. Rates of readmission/reoperation at 90 days did not differ between those with and without elevated tobacco markers. Clinically relevant thresholds of preoperative nicotine and/or cotinine values are needed to better delineate appropriate surgical candidates to achieve optimal surgical outcomes.

Cementless medial Oxford unicompartmental knee replacement. Five-year results from an independent series

BackgroundUnicompartmental knee replacement (UKR) is a common treatment option for patients with advanced medial compartment knee arthritis. The Oxford UKR (OUKR) is the most commonly used implant for partial knee replacement. A cementless Oxford prosthesis was introduced in 2004 aiming to reduce the revision rate by potentially reducing radiolucencies as well as errors of cementation associated with the cemented prosthesis. Whilst results from the designer centre have been reported, there is little independent clinical evidence of outcomes.The aim of this study was to evaluate the survival of the cementless OUKR in a single surgeon series at an independent centre and to assess clinical and radiographic outcomes. MethodsAll patients who received a cementless medial OUKR and had a minimum of five-year follow-up were included in the series. The Oxford knee score was used to evaluate patient outcomes at five years postoperatively. Survival rates, complications and evidence of radiolucencies on plain radiographs were also reviewed. ResultsOne hundred and fifty-eight cementless medial OUKR were implanted in 126 patients. Three patients died and four knees were revised. The five-year survival was 97.4% and the median Oxford knee score was 43 at five years postoperatively. No Complete radiolucent lines were observed on radiographs at one year. Four tibial components subsided. ConclusionsThis independent series shows that low revision rates and excellent results can be achieved with the use of the cementless OUKR at five years. Early subsidence of the tibial component, which is specific to the cementless prosthesis, warrants further investigation.

Uniportal Full Endoscopic Posterolateral Transforaminal Lumbar Interbody Fusion with Endoscopic Disc Drilling Preparation Technique for Symptomatic Foraminal Stenosis Secondary to Severe Collapsed Disc Space: A Clinical and Computer Tomographic Study with Technical Note

Background: Severe collapsed disc secondary to degenerative spinal conditions leads to significant foraminal stenosis. We hypothesized that uniportal posterolateral transforaminal lumbar interbody fusion with endoscopic disc drilling technique could be safely applied to the collapsed disc space to improve patients’ pain score, restore disc height, and correct the segmental angular parameters. Methods: We included patients who met the indication criteria for lumbar fusion and underwent uniportal full endoscopic posterolateral transforaminal lumbar interbody fusion with pre-operative Computer Tomography mid disc height of less than or equal to 5 mm and MRI of Grade 3 Foraminal Stenosis. Visual analogue scale and computer tomography pre-operative and post-operative sagittal disc height in the anterior, middle and posterior part of the disc; sagittal focal segmental angle; mid coronal disc height and coronal wedge angles were evaluated. Results: 30 levels of Endo-TLIF were included, with a mean follow up of 12 months. The mean improvement in decreasing pain score was 2.5 ± 1.1, 3.2 ± 0.9 and 4.3 ± 1.0 at 1 week post operation, 3 months post operation and at final follow up, respectively, p < 0.05. There was significant increase in mid sagittal computer tomographic anterior, middle and posterior disc height of 6.99 ± 2.30, 6.28 ± 1.44, 5.12 ± 1.79 mm respectively, p < 0.05. CT mid coronal disc height showed an increase of 7.13 ± 1.90 mm, p < 0.05. There was a significant improvement in the CT coronal wedge angle of 2.35 ± 4.73 and the CT segmental focal sagittal angle of 1.98 ± 4.69, p < 0.05. Conclusion: Application of Uniportal Endoscopic Posterolateral Lumbar Interbody Fusion in patients with severe foraminal stenosis secondary to severe collapsed disc space significantly relieved patients’ pain and restored disc height without early subsidence or exiting nerve root dysesthesia in our cohort of patients.

Short-term outcomes with the REDAPT monolithic, tapered, fluted, grit-blasted, forged titanium revision femoral stem.

Although good clinical outcomes have been reported for monolithic tapered, fluted, titanium stems (TFTS), early results showed high rates of subsidence. Advances in stem design may mitigate these concerns. This study reports on the use of a current monolithic TFTS for a variety of indications. A multi-institutional retrospective study of all consecutive total hip arthroplasty (THA) and revision total hip arthroplasty (rTHA) patients who received the monolithic TFTS was conducted. Surgery was performed by eight fellowship-trained arthroplasty surgeons at four institutions. A total of 157 hips in 153 patients at a mean follow-up of 11.6 months (SD7.8) were included. Mean patient age at the time of surgery was 67.4 years (SD 13.3) and mean body mass index (BMI) was 28.9 kg/m2 (SD 6.5). Outcomes included intraoperative complications, one-year all-cause re-revisions, and subsidence at postoperative time intervals (two weeks, six weeks, six months, nine months, and one year). There were eight intraoperative complications (4.9%), six of which were intraoperative fractures; none occurred during stem insertion. Six hips (3.7%) underwent re-revision within one year; only one procedure involved removal of the prosthesis due to infection. Mean total subsidence at latest follow-up was 1.64 mm (SD 2.47). Overall, 17 of 144 stems (11.8%) on which measurements could be performed had >5 mm of subsidence, and 3/144 (2.1%) had >10 mm of subsidence within one year. A univariate regression analysis found that additional subsidence after three months was minimal. A multivariate regression analysis found that subsidence was not significantly associated with periprosthetic fracture as an indication for surgery, the presence of an extended trochanteric osteotomy (ETO), Paprosky classification of femoral bone loss, stem length, or type of procedure performed (i.e. full revision vs conversion/primary). Advances in implant design, improved trials, a range of stem lengths and diameters, and high offset options mitigate concerns of early subsidence and dislocation with monolithic TFTS, making them a valuable option for femoral revision. Cite this article: Bone Joint J 2020;102-B(2):191-197.

The effect of surgical approach on early complications of total hip arthroplasty

BackgroundTotal hip arthroplasty (THA) is traditionally associated with a low complication rate, with complications such as infection, fracture and dislocation requiring readmission or reoperation. We seek to identify the complication rate among the anterior, direct lateral and posterior surgical approaches.MethodsWe reviewed all THAs performed at the Epworth Healthcare from 1 July 2014 to 30 June 2016. There were 2437 THAs performed by a variety of approaches. No hips were excluded from this study.We surveyed the hospital database and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) to identify those patients who had been readmitted and/or reoperated on. Details collected included age, gender, laterality of the surgery (left/right/bilateral), surgical approach utilised, complications which occurred.ResultsThere were 29 peri-prosthetic fractures detected (13 anterior, 9 lateral, 7 posterior) and 10 underwent revision of implant, 19 were fixed. The increased rate of revision in the anterior group was statistically significant.There were 14 dislocations (5 anterior, 1 lateral, 8 posterior) of which 8 prostheses were revised.Three cases operated via the anterior approach and 1 by the lateral had early subsidence without fracture, necessitating revision of the femoral prostheses.Operative site infection occurred in 12 cases (2 anterior, 4 lateral, 6 posterior) with 6 requiring revision of implants.ConclusionThe complication rates between the 3 main approaches are similar, but individual surgeons should be vigilant for complications unique to their surgical approaches, such as femoral fractures in the anterior approach and dislocations in the posterior approach.

Five-year prospective subsidence analysis of 100 cemented polished straight stems: A concise clinical and radiological follow-up observation.

Early subsidence (>1.5mm) has been shown to be an indicator for later aseptic loosening of cemented hip stems. For the cemented twinSys® stem we published excellent short-term results at 2 years. Midterm data for this stem are available from national registers (NZL, NL), however in all of these sources, clinical and radiological results are missing. Aim of our study was to analyse mid-term survival and radiological changes around the cemented twinSys® stem with special emphasis on subsidence using EBRA-FCA. We conducted a prospective clinical and radiological 5- year follow-up study of 100 consecutive hybrid total hip arthroplasties (THA) using a polished, cemented collarless straight stem (twinSys®, Mathys AG® Bettlach, Switzerland) with a cementless monobloc pressfit cup (RM pressfit®, Mathys AG® Bettlach, Switzerland). Median age at surgery was 79 (69 to 93) years. No patient was lost to follow-up. Survival rates were calculated using the Kaplan-Meier method. Clinical (Harris Hip Score [HHS]) and radiological (cementing quality, alignment, osteolysis, debonding and cortical atrophy) outcomes and an in-depth subsidence analysis using EBRA-FCA were performed. 22 patients died in the course of follow-up unrelated to surgery, 21 stems had an incomplete radiological follow-up. 2 stems were revised, both due to an infection. The survival rate for the stem at 5 years was 98.0% (95% CI 95.3-100%). The survival rate of the stem for revision due to aseptic loosening at 5 years was 100%. The HHS improved from 53 (14-86) points preoperatively to 90 (49-100) points 5 years after surgery. Osteolysis was found in 2 stems without clinical symptoms. In 49 out of 55 patients with a complete radiological follow- up, the EBRA-FCA analysis was possible and showed an average subsidence of 0.66 (95% CI 0.46 to 0.86) mm 5 years after surgery. 10 patients showed a subsidence >1 mm, 5 of which bigger than 1.5 mm. Subsidence was independent from radiological changes and cementing quality.The cemented twinSys® stem showed excellent clinical and radiological mid-term results at five years’ follow-up and seems to be a reliable implant.

Similar clinical results and early subsidence between the Collum Femoris Preserving and the Corail stem: a randomized radiostereometric study of 77 hips with 2 years’ follow-up

Background and purpose — Femoral neck preserving hip replacement has been suggested to improve clinical results and facilitate late revision. We compared the 2-year outcome and radiostereometric pattern of femoral head migration between the Collum Femoris Preserving (CFP) stem and the Corail stem.Patients and methods — 83 patients were randomized to either a CFP stem or a Corail stem. All patients received the same cup. At 2 years clinical outcomes were assessed using validated scoring systems and plain radiographs. 2-year migration was determined using radiostereometric analysis.Results — At 2 years the clinical outcomes (Oxford Hip Score, Harris Hip Score, SF-36, EQ5D-VAS, satisfaction VAS, and pain VAS) were similar between the 2 groups. The radiographic measurements showed that the femoral neck was resected around 1 cm more proximally with use of CFP stems (p < 0.001). The proximal–distal and medial–lateral migration of the femoral head center was similar. The Corail stem showed increased posterior displacement after 1 year, but no difference was found between the absolute translations in the anterior–posterior direction (p = 0.2). 2 CFP stems were revised due to loosening within the first 2 years. None of the Corail stems was revised.Interpretation — In the 2-year perspective clinical outcomes suggested no obvious advantages with use of the CFP stem. The magnitude of the early stem migration was similar, but the pattern of migration differed. The early revisions in the CFP are a cause of concern.Trial registration: ClinicalTrials.gov identifier: NCT02983526.

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.

Neural Network as an Assisting Tool in Designing Talus Implant

The design of current talus implant are focusing too much on mechanical simplicity and usually based on certain population which tends to ignore the anatomically difference between populations. An anatomically talus implant design is known can reduce the contact pressure but one of the constraints for designing implant anatomically is to get bone parameters. This is due to the difficulty to get enough volunteers in getting bone parameters using hazardous method (X-ray or CT scan) .Thus, the talus implant (TI) for particular population was developed based on artificial neural network (ANN) prediction. By using Finite Element Method (FEM), numerical models that include mainly the talus bone and the talus implants are created to compare the contact pressure distribution of the newly develop talus implant with the three different kind of current talus implant designs (BOX, STAR &amp; TNK). For FEM results, only BOX and the newly develop talus implant exceeded the contact stress recommended for the superior articular surface compared to the others. The results also showed that the stress increased near the resected surface. Thus, it is agreed that excessive bone resection may not support the force at the ankle which consequently may contribute to early loosening and subsidence of the talus implant. It is concluded that the excessive bone resection can be avoided by perfectly match talus implant which only can be achieved by designing talus implant for a particular population.

Cementless Stem for Femoral Neck Fractures in a Patient's 10th Decade of Life: High Rate of Periprosthetic Fractures.

Background:Subsidence of cementless femoral stems in hemiarthroplasty (HA) and increased fracture rates are ongoing concerns of orthopedic surgeons when treating fractures in very old patients. Additionally, bone cement implantation syndrome may result in perioperative cardiac or pulmonary complications, especially in older patients, leading to morbidity and mortality. This study was performed to analyze possible subsidence and intraoperative fractures in a cohort of very old patients treated with cementless stems.Methods:We retrospectively analyzed a consecutive cohort of patients aged ≥90 years with femoral neck fractures treated by uncemented HA and an anterior minimally invasive approach. Immediate full-weight bearing was allowed postoperatively. Pelvic radiographs were examined for subsidence immediately postoperatively and 6 weeks later.Results:We treated 109 patients (74% women; mean age, 93 years; range, 90-102 years) by HA from January 2010 to March 2016. The 30-day mortality rate was 16%, and the morbidity rate was 47%. There were 11 (12%) intraoperative fractures: 8 (Vancouver B2) had to be addressed immediately during the primary operation, while 3 (1 Vancouver B1 and 2 Vancouver AG) were treated conservatively. One periprosthetic femoral fracture (Vancouver B1) was documented during follow-up. In 17 patients, subsidence of >2.0 mm (median, 3.9 mm; range, 2.5-9.0 mm) was documented.Conclusion:Early subsidence was low in this very old cohort treated with an uncemented stem and not showing a periprosthetic fracture. The risk of intraoperative periprosthetic fractures was high. The use of uncemented implants in osteoporotic bone continues to be an intervention with high risk and should only be performed by experienced surgeons.Level of Evidence:Level III, Therapeutic study.

Influence of undersized cementless hip stems on primary stability and strain distribution.

Undersizing of cementless hip stems is a risk factor for aseptic loosening and early subsidence. The purpose of this study was to evaluate the effects of undersized stems and determine whether a biomechanical study can predict the clinical results. Three consecutive sizes of a clinically proven stem (CLS Spotorno) were implanted into six composite femora (size large, Sawbones®), respectively. According to the Canal Fill Index (CFI), two stems (size 11.25 and 12.5) were undersized (CFI<80%) and one stem (size 13.75) had an appropriate size (CFI>80%). The primary stability was evaluated by measurement of 3-dimensional (3D)-micromotions under physiological adapted load and surface strains were recorded before and after implantation to detect stress-shielding processes. Both undersized stems revealed significantly higher micromotions in all regions compared to the appropriate stem. The highest micromotions were registered at the distal tip of the three stem sizes. The changes in surface strain did not show a significant difference between the three stem sizes, but the highest strain reduction was observed proximally indicating a tendency for stress shielding. This study confirms the clinical assumption that undersized stem result in a significantly reduced primary stability. Furthermore, in vitro studies allow to determine the effects of undersizing and stress shielding processes.

Effect of stem sizing and position on short-term complications with canine press fit cementless total hip arthroplasty.

To determine the influence of stem sizing and positioning with early subsidence and stem complications with cementless (BFX) total hip arthroplasty (THA). Retrospective case series. Fifty-five dogs; 58 THAs. Eighty cobalt-chromium BFX THAs were reviewed, 58 met inclusion criteria. Implant size, positioning, and major complications within 12 months of surgery were recorded. Femoral canal flare (FCF), canal fill, stem angle, and subsidence at 3 months were measured from postoperative radiographs. Appropriateness of final stem size was assessed with digital templates. Odds ratios for associations were calculated. Mean ± SD coronal canal fill (Fillcor ) was 75% ± 6, FCF was 2.0 ± 0.3, and subsidence was 1.7 mm ± 2.6. Stem angulation ranged from 7° varus to 6° valgus, and 7° cranial to 3° caudal. Appropriately sized stems (n = 45) had a mean Fillcor of 78%. Major stem complications occurred in 12% of THAs. Femora with subsidence > 3 mm were 45.3 times more likely to develop postoperative stem complications (P = .02). Stems with varus angulation ≥ 5° were 12.5 times more likely to sustain intraoperative fissures (P = .03). Stems considered undersized based on postoperative digital templating were 5.6 times more likely to develop stem complications (P = .04) and 5.7 times more likely to subside > 3 mm (P = .03). Varus stem angulation should be avoided to prevent fissures. Canal fill is a poor indicator of optimal stem size and the current recommendation of >85% is unnecessarily high. Postoperative templating may be useful for assessing appropriateness of stem size.

Botulinum toxin in the management of acquired abducens nerve palsy: Prospective Interventional controlled trial

Aim: The aim of this study is to assess the effectiveness of botulinum toxin in patients presenting with isolated lateral rectus palsy. Materials and Methods: This prospective interventional controlled trial from March 2012 to March 2015. Inclusion criteria were acquired lateral rectus palsy, no other neurological defects, normal magnetic resonance imaging scan, and age >30 years. The cases were treated with 15–25 units of botulinum toxin depending on the angle of squint. The surgical field is prepared, the medial rectus insertion grasped firmly with forceps, and the eye rotated to the primary position. Botulinum toxin is injected 5 mm from the medial rectus insertion, inside the bulk of muscle through a 27-gauge needle (without electromyographic guide) under topical anesthesia. No peritomy is done. Controls were treated with intravenous steroids for 3 days changed to oral steroids on tapering doses. Cases and controls were followed up 10, 30, 60, 120, and 180 days after initiating treatment. Wilcoxon signed-rank test is used for paired samples; Mann–Whitney U-test is for independent samples; P Results: Ten cases (six female) were enrolled into the study. Ten age-matched controls (six female) were also enrolled. The baseline characteristics of cases and controls were comparable in terms of duration of symptoms, head posture, primary deviation in the primary position, and limitation of abduction. After 10 days of injection, 100% of cases attained primary deviation Conclusion: Botulinum toxin is effective in achieving early subsidence of diplopia in the primary position and early recovery of abduction in patients presenting with isolated lateral rectus palsy.

Prospective two-year subsidence analysis of 100 cemented polished straight stems - a short-term clinical and radiological observation.

BackgroundCemented stems show good long-term results and the survival of new implants can be predicted by their early subsidence. With EBRA-FCA (Femoral Component Analysis using Einzel-Bild-Röntgen-Analyse) early subsidence as an early indicator for later aseptic loosening can be analysed. For the cemented TwinSys stem mid- and long-term data is only avalible from the New Zeeland Arthroplasty register, thus close monitoring of this implant system is still mandatory.MethodsWe conducted a 2 year follow up of 100 consecutive hybrid THA (Total hip arthroplasty) of a series of 285 primary THA operated between Jan 2009 und Oct 2010. These 100 received a polished, cemented collarless straight stem (twinSys®, Mathys AG® Bettlach, Switzerland) with an uncemented monobloc pressfit cup (RM pressfit®, Mathys AG® Bettlach, Switzerland). The other patients were treated with the uncemented version of this stem and the same cup. Clinical (Harris Hip Score) and radiological (ap and axial x-rays, cementing quality according to Barrack, alignment) outcomes besides an EBRA-FCA subsidence analysis were performed.ResultsMedian age at operation was 78 (68 to 93) years. 5 patients died in the course of follow-up unrelated to surgery. The KM (Kaplan-Meier) survival at 2 years for the endpoint reoperation for any reason was 94.9 (95 % confidence interval 90.6–100 %). Survival for the endpoint aseptic loosening at 2 years was 100 %.The HHS (Harris Hip Score) improved from 56 (14–86) preoperatively to 95 (60–100) 2 years after the operation. Cementing results were judged 47 % Grade A, 45 % Grade B and 7 % Grade C.Osteolysis was found in 2 stems without clinical symptoms or correlation to subsidence or cementing quality. The EBRA-FCA analysis showed an average subsidence of -0.30 mm (95 % CI -0.5 mm to -0.1 mm). 11 patients showed a subsidence of more than 1 mm. In this group one patient showed a subsidence of 1.5 mm and one of 3.1 mm without further radiological changes.ConclusionsThe twinSys stem showed excellent clinical and radiologic short term results at 2 years follow-up and seems to be a reliable implant.

Differences in subsidence rate between alternative designs of a commonly used uncemented femoral stem

IntroductionMeasurement of early subsidence of uncemented femoral stems can be used to evaluate the likelihood of long term stem component loosening and therefore clinical failure.Our aim was to evaluate the factors associated with subsidence in collared and uncollared versions of the Corail femoral stem. Methods121 hips in 113 consecutive patients were studied, operated on by two surgeons in our hospital differing in their choice of Corail stem. This gave two groups of patients with 66 hips having collared stems and 55 hips having uncollared. We recorded patients’ age, sex, ASA grade and BMI. Radiographs post-operatively at day 1, 6 weeks and 1 year were evaluated measuring subsidence, angulation, signs of stability and fixation, and canal fill ratio at the metaphysis and diaphysisafter correcting for magnification errors by calibration using femoral head size. ResultsClinically significant subsidence (>3mm) occurred in 7.6% of collared and 10.9% of uncollared stems, all within 6–8 weeks, but did not reach statistical significance (p=0.345). Revision for symptomatic loosening was required in 1 patient in each group (1.5% collared versus 1.8% uncollared). DiscussionEarly subsidence of Corail femoral stem should alert surgeons to closer patient follow-up as the rate of early revision is 18% in stems with >3mm of subsidence. However, the presence of a collar does not seem to be protective.

CORR Insights(®): Early Subsidence Predicts Failure of a Cemented Femoral Stem With Minor Design Changes.

CORR Insights(®): Early Subsidence Predicts Failure of a Cemented Femoral Stem With Minor Design Changes.

Post-rift subsidence of the French Guiana hyper-oblique margin: from rift-inherited subsidence to Amazon deposition effect

Abstract The recent surge of exploration activities over distal margins, with the acquisition of more and more high-quality and deep seismic data, has led to enhance concepts of the deformation and subsidence history of passive margins in general and sheared margins in particular. The French Guiana sheared margin is very narrow. The thinning of the upper crust is accommodated by few major faults relayed by well-expressed transfer zones, giving a general oblique trend to the margin. Another possible effect of the shear component during the rifting is the presence in the distal domain of a Moho high. Its exhumation is coeval with the emplacement of a deltaic system coming from the Demerara Plateau, evidencing a probably important early subsidence of the margin. This early subsidence in the late-rifting stage is increased during the early drifting, when the thinned crust reached its isostatic/thermal equilibrium in the Cenomano-Turonian before suffering an important Late Cretaceous sedimentation load. In the Palaeogene, starving of the margin and significant uplifts in the Guiana Craton are observed, possibly resulting from the rise of the Purus Arch (Andes fore-bulge?). Finally, the Amazon deposition by the Late Miocene–Pliocene provoked a large subsidence in the distal domain.

Uncemented hip arthroplasty for failed internal fixation of peritrochanteric fracture

Objective To observe the outcome of uncemented hip arthroplasty for failed internal fixation of intertrochanteric fracture. Methods Seventeen patients admitted from Februaty 2010 to January 2014 were reviewed retrospectively in this study. The patients aged 67.2 years(range, 41-80 years) composed 6 males and 11 females. There were 15 patients with intertrochanteric fracture and 2 intertrochanteric and subtrochanteric fracture. The primary internal fixation method was dynamic hip screw (DHS) fixation in 2 patients, proximal femoral nail anti-rotation(PFNA) fixation in 12 patients and intramedullary nailing in 3 patients. Arthroplasty with a prosthetic hip was performed for 15 patients and with a prosthetic femoral head was done for 2 patients 3-48 months after the internal fixation. Harris score was used for evaluation of the results of hip arthroplasty. Preoperative Harris score was (32.6±6.8)points. Results All the patients were followed up for 6 to 48 months. One patient with intraoperative femoral fracture experienced early subsidence and dislocation of femoral stem following allogeneic bone plate and titanium cable fixation and had further revision surgery. One patient had secondary subsidence of the femoral stem without pain and limitation of motion. One patient had primary infection recurrence after arthroplasty, but the infection remained uncured even after a series of treatments like repeated debridements, sustained vacuum drainage, prosthesis removal, debridement and temporary spacer implantation. Sixteen patients showed postoperative pain relief and good hip function recovery characterized by the ability to care for themselves and no prosthetic loosening. Harris hip score significantly improved to (79.2±15.9)points at the final follow-up (P<0.01). Conclusions Uncemented hip arthroplasty is an effective method for the failed internal fixation of peritrochanteric fracture. The procedure achieves satisfactory function recovery, early weight-bearing exercise and early recovery of self-care ability, and avoids the complications of bone cement use. Key words: Arthroplasty, replacement, hip; Hip fractures; Treatment failure