High incidence of migration with poor initial fixation of the Accolade stem

Incidence and Predictors of Subsidence Using Modular, Tapered, Fluted Titanium Femoral Stems in Aseptic Revision Total Hip Arthroplasty

BACKGROUND

Tapered, fluted titanium (TFT) femoral stems have become the gold standard in revision total hip arthroplasty (rTHA). However, there is a paucity of data on TFT stem subsidence rates following aseptic rTHA. Subsidence can lead to instability, mechanical failure, leg-length discrepancy, and may require revision surgery. This study evaluated the incidences and predictors of TFT subsidence in aseptic rTHA.

METHODS

A total of 102 TFT femoral stems of 4 designs were retrospectively reviewed. Stem subsidence was measured on digital radiographs taken immediately after surgery and at standard clinical follow-up. Patient characteristics, risk factors for subsidence, revision etiologies, and implant characteristics were recorded. Patient-reported outcome measures were also evaluated for a subset of cases.

RESULTS

Overall, 12% of stems subsided >1 cm, and subsidence was minimal (<3 mm) in ≥64% of cases. From immediate postoperative to 1-month radiographic follow-up, 79% of stems subsided a mean of 2.9 mm (range, 0.1 to 12 mm). Beyond 1 month, subsidence was minimal for ≥77% of cases. In multivariate analyses, women and less femoral implant canal fill were associated with greater subsidence (P ≤ .034). The TFT stem design was not associated with early subsidence (P = .816). There were no modular junction fractures. There were 2 fractures and 2 subsidence-related revisions for aseptic loosening that occurred postoperatively.

CONCLUSIONS

The amount of subsidence in TFT stems was low and was detectable in the early (less than 1 year) postoperative period. Maximizing TFT stem fill within the femoral canal appears to reduce the risk of subsidence without increasing femoral fracture rates and should be the goal with implantation of these devices.

LEVEL OF EVIDENCE

IV-Case Series, No Control Group.

Novel radiologic indices for stem type decision in total hip arthroplasty in patients with metaphyseo-diaphyseal mismatched Dorr A proximal femur

BACKGROUND

In metaphyseo-diaphyseal (M-D) mismatched Dorr A femurs, it is difficult to achieve proper fixation with a type 1 stem. Proper interpretation of the geometry of the femur is integral at the preoperative stage in an M-D mismatched femur, but there has been a scarcity of studies on the radiologic indices. Therefore, we analyze the previous radiologic indices and suggest the novel ones for M-D mismatched femurs.

METHODS

Our study was a retrospective review of preoperative radiographs of patients who underwent total hip arthroplasty with the smallest type 1 stem or with type 3 C stem at a single institution from July 2014 to March 2022. A Type 3 C stem was used when the smallest type 1 stem failed to achieve metaphyseal fixation. One hundred twenty-six patients were categorized into two main groups. Canal-flare index, canal-calcar ratio, modified morphological cortical index, and two novel indices (lesser trochanter-to-distal ratio-α and -β [LDR-α and -β]) were assessed on preoperative pelvic radiographs.

RESULTS

Multivariate and ROC analysis demonstrated that high LDR-β (Exp[B]: 485.51, CI: 36.67-6427.97, p < 0.001) was associated with a more mismatched tendency group and had clinically acceptable discriminatory power (AUC: 0.765, CI: 0.675-0.855, p < 0.001) between the two cohorts.

CONCLUSION

Correct assessment of preoperative femoral morphology would be fundamental in the selection of a suitable stem. The ratio based on 3 cm below the lesser trochanter of the femur seemed crucial. We recommend evaluating the newly described radiological index preoperatively in M-D mismatched Dorr A femur for planning precisely and selecting a proper stem.

Stem alignment with short tapered-wedge cementless stems affects bone mineral density continuously for at least 5 years after primary total hip arthroplasty

AIM

This study aimed to assess the relationship between the three-dimensional (3D) alignment of short tapered-wedge cementless stems and bone mineral density (BMD) changes in patients followed up for 5 years after total hip arthroplasty (THA).

METHODS

We retrospectively analysed the hips of 52 patients who underwent THA using short tapered-wedge cementless stems at our institution from 2013 to 2016 with complete 5-year follow-up data. We evaluated the relationship between stem alignment, measured using a 3D-templating software, and BMD changes in the 7 Gruen zones.

RESULTS

After 1 year, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD in zones 3 and 4 were noted. After 5 years, significant negative correlations between varus insertion and a decrease in BMD in zone 7 and between flexed insertion and decreases in BMD zones 2, 3, and 4 were observed. With increased amounts of varus/flexion stem alignment, the amount of BMD loss decreased. There was no correlation between anteverted stem insertion and changes in BMD levels.

CONCLUSIONS

Our data showed that stem alignment affects BMD based on 5-year follow-up data after surgery. Careful observation is necessary, especially when using short tapered-wedge cementless stems, as stem alignment may affect changes in BMD levels more than 5 years after surgery.

Early Radiographic Fit and Fill Analysis of a New Metaphyseal-Filling Triple Taper Stem Designed Using a Large Computed Tomography Scan Database

Background

Numerous cementless stems are available to maximize implant stability, fit, and survivorship in total hip arthroplasty. Recently, a new metaphyseal-filling triple-taper collared stem was designed using femoral morphology data obtained from over 1300 computed tomography scans. The purpose of this study was to evaluate the radiographic fit and fill of this new stem in the coronal and sagittal dimensions.

Methods

In this retrospective review, postoperative radiographs of patients receiving this new stem were analyzed in accordance with previously published fit and fill analyses. All radiographs were taken 6 weeks postoperatively. Means and standard deviations were reported for all fit and fill parameters.

Results

Fifty-nine hips were analyzed from 55 patients undergoing total hip arthroplasty. The coronal proximal fill was 85.02 ± 8.06%, and coronal distal fill was 75.21 ± 9.71%. The sagittal proximal fill was 86.51 ± 8.77%, and sagittal distal fill was 59.17 ± 8.66%. Mean calcar collar coverage was 80.64 ± 19.6% and all patients had full seating of the collar. Six cases (10.2%) had a collar length greater than the calcar length, with a mean collar overhang of 0.7 ± 0.4 mm.

Conclusions

This new stem demonstrated significant proximal fill in both the coronal and sagittal planes and validates the design intent of this implant. This is the first study to evaluate sagittal fit and fill of a femoral stem. Long-term follow-up is required to understand the clinical impact these fit and fill characteristics may have on patients' long-term outcomes.

Mid-Term Migration Behavior of an Uncemented Proximally Anchored Straight Stem-A Retrospective EBRA Migration Analysis

BACKGROUND

Aseptic loosening is one of the most-common causes of the failure of cementless stems. Einzel Bild Röntgen Analyse-Femoral Component Analysis (EBRA-FCA) allows the diagnosis of stem migration, which can be considered a factor in predicting implant survival. The current study aimed to present the migration behavior of a tapered proximally anchored straight stem.

METHODS

This retrospective study reviewed all consecutive patients who received a cementless CBC straight stem (Mathys AG, Bettlach, Switzerland) between 2005 and 2019. We analyzed the migration pattern using the EBRA-FCA software and reviewed their medical histories. In addition, periprosthetic radiolucency was rated according to the Gruen zones and femoral configuration according to Dorr.

RESULTS

A total of 333 stems in 332 patients (female 191; male 141) met our inclusion criteria. The mean age at surgery was 63 (range 21-87) years. Migration analysis by EBRA-FCA showed a mean subsidence of 1.6 mm at final follow-up at 96 months with a maximum noted mean subsidence of 2.0 mm at 72 and 84 months. Dorr Type A showed a tendency of less subsidence than did Dorr Type B and was statistically significant at 6 (p = 0.0396) and 72 months (p = 0.0127). The body mass index (BMI) and increased subsidence were not found to correlate (p > 0.05). For this cohort, the overall femoral revision-free rate was 95.2% and the revision-free rate for aseptic loosening was 99.1%.

CONCLUSIONS

The results showed migration behavior in cementless stems with initial increased migration and subsequent secondary stabilization, suggesting an excellent long-term outcome. Stem migration of this tapered proximally anchored stem might be lower in Dorr Type A than in Dorr Type B femurs without being statistically significant at all time points.

Subsidence of a Single-Taper Femoral Stem in Primary Total Hip Arthroplasty: Characterization, Associated Factors, and Sequelae

BACKGROUND

We characterized subsidence of an uncemented single-taper femoral stem in primary total hip arthroplasty (THA), determined factors associated with subsidence, and evaluated the impact of subsidence on outcome.

METHODS

This retrospective study included 502 primary THAs performed using a single-taper stem in Dorr type A and B femora between 2014 and 2018. Subsidence was measured based on distance from the greater trochanter to stem shoulder on calibrated X-rays. Demographics, case-specific data, and outcomes were collected. Changes in subsidence and variables associated with subsidence were determined.

RESULTS

Stem subsidence was 1.5 ± 2.3 mm, 1.6 ± 2.0 mm, 2.0 ± 2.6 mm, 2.3 ± 2.3 mm, 2.6 ± 2.5 mm, and 2.7 ± 3.0 mm at 6 weeks, 3 months, 6 months, 1 year, 2 years, and ≥3 years from THA, respectively. Subsidence across all patients at final mean follow-up of 24 months (range, 1 to 101 months) was 2.2 ± 2.6 mm. Pairwise comparison demonstrated that subsidence occurred predominantly within the first 6 months. Significant subsidence (≥5 mm) occurred in 17.3% and was associated with a body mass index (BMI) ≥25 (P=0.04). Dorr type, age, sex, and American Society of Anesthesiologists class were not associated with subsidence. There were two patients (0.4%) who underwent a revision that could be attributed to subsidence. There was no association between subsidence and pain, limp, need for ambulatory aid, or analgesic use.

CONCLUSION

In primary THAs performed using a single-taper prosthesis, average subsidence was 2.2 mm and significant subsidence occurred in 17.3%. Patient BMI was associated with subsidence. Revision surgery related to subsidence was infrequent (0.4%).

Penalty for Switching Implants? Assessing the Learning Curve With a Collarless, Tapered Wedge Cementless Femoral Component

Background

Surgeon learning curve associated with a tapered wedge femoral implant as measured by early femoral component subsidence and 90-day risk of reoperation was evaluated.

Methods

The first 451 patients undergoing primary, cementless total hip arthroplasty by a single, fellowship-trained arthroplasty surgeon with a tapered wedge stem design were retrospectively reviewed. Early radiographic femoral component subsidence during the first 6 weeks postoperatively and 90-day reoperations was recorded.

Results

When stratified by approach, there was no association between date of surgery and femoral component subsidence in the posterior approach (P-value for linear trend over time = 0.44). In the direct anterior approach, there was a significant association between date of surgery and early femoral component subsidence (P-value for linear trend over time = 0.01). For both approaches, there was an increase in implanted stem size relative to templated stem size over time (P < .01 and P = .03, respectively). There was no association between the date of surgery and risk of 90-day reoperation (P = .45).

Conclusions

In a single surgeon's initial use of a tapered cementless wedge stem, early femoral component subsidence was not impacted by the surgeon's learning curve when the posterior approach was utilized. Although subsidence was associated with date of surgery in the direct anterior cohort, this was not associated with increased risk of 90-day reoperation. Should a surgeon adopt a new tapered-wedge stem, these findings suggest that the stem is forgiving both in relation to subsidence and 90-day reoperation risk when appropriate surgical technique is utilized.

Component Asymmetry in Bilateral Cementless Total Hip Arthroplasty

Background

This study investigated the results of component asymmetry (CA) in bilateral cementless total hip arthroplasty (THA).

Methods

This study included 300 patients, who underwent bilateral cementless THA between April 2000 and December 2017. They were divided into the component symmetry (CS) and CA groups; CA group was sub-classified into acetabular component asymmetry (ACA) and femoral component asymmetry (FCA). Radiologic and clinical outcomes of the CA group were compared with those of the CS group.

Results

The incidence of CA was 25.7% (77/300 patients), including 55 patients with ACA, 34 patients with FCA, and 12 with both components asymmetric. The mean time interval between operations in the CA group was significantly longer than that in the CS group (p < 0.001). The mean differences in horizontal and vertical distances from teardrop to the center of rotation of the acetabular component between both hips in the ACA group were significantly larger than those in the CS group (p = 0.033 and p < 0.001, respectively). The mean femoral component alignment angle difference between both hips was significantly larger in the FCA group than in the CS group (p < 0.001). The mean Harris Hip Score at last follow-up of the CA group was similar to that of the CS group.

Conclusions

CA in patients undergoing bilateral cementless THA was not rare, especially with a longer time interval between operations. Regardless of CA, when stable fixation of the components was achieved, satisfactory radiologic and clinical outcomes were obtained.

Middle-term outcome and complications after primary total hip arthroplasty using a contemporary titanium tapered wedge cementless femoral stem

The purpose of this study is to evaluate the results and intraoperative or postoperative complications of primary total hip arthroplasty (THA) using a contemporary tapered wedge titanium femoral component. A total of 213 THAs in 187 patients were followed up more than 5 years (mean, 102 months ; range, 60-150). The mean age at surgery was 64.2 years (range, 20?89 years). These patients were clinically evaluated using the JOA scoring system and radiographically host bone reactions around the implants, as well as femoral loosening. The mean JOA score improved from 49 (range, 21?75) to 92 (range, 59?100). All 12 patients with poor results (JOA < 75) coexisted with cerebral, spinal, joint, and musculoskeletal disorders. At the final follow-up, implant survival was 100%. Complications occurred in 23 hips. They consisted of 12 hips with intra-operative fractures, 2 hips with sciatic nerve palsy, one hip with infections, 3 hips with recurrent dislocations, and 8 hips with aseptic cup loosening. In conclusion, we have shown excellent survival rate of the contemporary tapered wedge stem in primary THA ; however, patients with coexisting diseases could not acquire sufficient improvement in hip function and ambulatory ability. J. Med. Invest. 70 : 471-475, August, 2023.

Differences in peri-hip articular pain after total hip arthroplasty between taper wedge stem and fit-and-fill stem

Background

Total hip arthroplasty (THA) for hip disorders helps to alleviate pain and improve active daily life. When determining the effects of medical therapy and the subsequent clinical results, patient quality of life (QOL) also needs to be assessed. Recently, patient-reported outcomes (PRO) have become important as evaluation criteria. This study aimed to evaluate patient QOL and various PRO between different types of cementless stems and to clarify the relationship between PRO and stem-cortical bone contact.

Methods

The study comprised 138 consecutive patients undergoing cementless THA for hip osteoarthritis. We assessed three different types of PRO: the Japanese Orthopaedic Association Hip-Disease Evaluation Questionnaire (JHEQ), patient's joint perception, and peri-hip articular joint pain (PHAP). We measured the state of contact between femur and implant by density mapping.

Results

No significant difference was noted in PRO between stem types based on the JHEQ and patient's joint perception. PHAP occurred more frequently in the patients with a taper wedge stem versus a fit-and-fill stem. In both groups, distal contact was associated with PHAP but not with JHEQ results and patient's joint perception.

Conclusion

The difference in PHAP between the two stem types groups was significant, with postoperative PHAP being higher with the taper wedge stem because of the more distal contact between the taper wedge stem and femur cortical bone.

Can We Predict Fracture When Using a Short Cementless Femoral Stem in the Anterior Approach?

BACKGROUND

Short cementless femoral stems may allow for easier insertion with less dissection. The use of short stems with the anterior approach (AA) may be associated with a considerable perioperative fracture risk. Our aim was to evaluate whether patient-specific femoral and pelvic morphology and surgical technique, influence the perioperative fracture risk. Furthermore, we sought to describe important anatomical thresholds alerting surgeons.

METHODS

A single-center, multi-surgeon retrospective, case-control matched study was performed. Thirty nine periprosthetic fractures (3.4%) in 1,145 primary AA THAs using short cementless stems were identified. These were matched with 78 THA nonfracture controls for factors known to increase the fracture risk. A radiographic analysis using validated software measured femoral (canal flare index [CFI], morphological cortical index [MCI], and calcar-calcar ratio [CCR]) and pelvic (Ilium-ischial ratio [IIR], ilium overhang, and anterior superior iliac spine [ASIS] to greater trochanter distance) morphologies and surgical techniques (% canal fill). A multivariate and Receiver-Operator Curve (ROC) analysis was used to identify fracture predictors.

RESULTS

CFI (3.7 ± 0.6 vs 2.9 ± 0.4, P < .001) and CCR (0.5 ± 0.1 vs 0.4 ± 0.1, P = .006) differed. The mean IIR was higher in fracture cases (3.3 ± 0.6 vs 3.0 ± 0.5, P < .001). Percent canal fill was reduced in fracture cases (82.8 ± 7.6 vs 86.7 ± 6.8, P = .007). Multivariate and ROC analyses revealed a threshold CFI of 3.17 which was predictive of fracture (sensitivity: 84.6%/specificity: 75.6%). The fracture risk was 29 times higher when patients had CFI >3.17 and II ratio >3 (OR: 29.2 95% CI: 9.5-89.9, P < .001).

CONCLUSION

Patient-specific anatomical parameters are important predictors of a fracture-risk. A careful radiographic analysis would help identify those at a risk of early fracture using short stems, and alternative stem options should be considered.

Intermediate to Long-Term Outcomes and Causes of Aseptic Failure of an At-Risk Femoral Stem

BACKGROUND

The Accolade TMZF is a tapered-wedge cementless metaphyseal-coated femoral stem that was widely utilized from 2002 to 2012. In recent years, there have been reports of early catastrophic failure of this implant. The purposes of the present study were to establish the long-term survival of this stem and to analyze patients who underwent aseptic revision to understand the causes and risk factors for failure.

METHODS

We retrospectively reviewed the records of all patients who had undergone primary total hip arthroplasty with use of an Accolade TMZF stem at a high-volume arthroplasty center. The causes and timing of revision surgery were documented. Survivorship analysis was performed with use of Kaplan-Meier curves to determine the overall and aseptic survival rates at the time of the latest follow-up. Patient and implant factors commonly associated with aseptic failure were extracted, and a Cox proportional hazards model was used.

RESULTS

A consecutive series of 2,609 patients who had undergone unilateral primary total hip arthroplasty with use of an Accolade TMZF femoral stem were included. The mean time from the primary procedure was 11.3 years (range, 0 days to 19.4 years). The cumulative survival rate was 95.5% ± 0.1% at the time of the latest follow-up. One hundred and seven patients underwent revision surgery, with aseptic loosening of the femoral component being the most common cause of aseptic failure in this cohort (33 of 2,609; 1.3%). Smaller femoral size and larger femoral head offset were independent risk factors for aseptic failure.

CONCLUSIONS

To our knowledge, this is the largest series representing the longest follow-up of this tapered-wedge cementless femoral implant. Despite early concerns, the Accolade TMZF stem had excellent survivorship in this cohort. Trunnionosis as the cause for revision surgery was rare.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Fracture of a titanium femoral neck after revision total hip arthroplasty

We report a case of a fractured titanium alloy (Ti6Al4V) femoral stem 2 years after revision (debridement, antibiotics and implant retention due to periprosthetic joint infection) total hip arthroplasty (THA). Material analysis revealed a superficial abnormality on the upper neck surface caused by local melting with electrocautery probably acting as a stress amplifier. This lesion presumably was the trigger of a fatigue fracture with typical features on the fracture surface. Electrocautery should therefore be avoided in case of revision THA or used with utmost care to avoid contact with the femoral stem.

Early failure of an uncemented femoral stem, as compared to two other stems with similar design, following primary total hip arthroplasty performed with direct anterior approach

INTRODUCTION

An increased risk of early femoral component loosening has been reported using the direct anterior approach (DAA) compared with other common surgical approaches. However, long-term data are scarce. The purpose of this study is: (1) to determine the incidence of early femoral loosening in a high volume, single surgeon's practice utilising the DAA approach; and (2) to examine the effect of stem design and type of coating on aseptic loosening in the early and mid-term postoperative period.

METHODS

A retrospective review of 1650 consecutive patients (1800 hips) who underwent total hip arthroplasty (THA) using the DAA between August 2011 and December 2017 was conducted at our institution. 3 types of uncemented femoral stems (Quadra-S, Avenir, TwinSys), with similar design, but different coating, were implanted. Patients were evaluated clinically and radiologically at 4 weeks, 3 months, 1 year, and annually thereafter.

RESULTS

After a mean follow-up of 46.4 months, the total incidence of revision for aseptic loosening was 0.44% (n = 8). All loose stems were Quadra-S, failing to achieve osseointegration, for an overall incidence of 0.96% (p = 0.002). None of the other stems were loose. Radiolucent lines around the proximal stem portion were visible in 75 Quadra-S stems (4.1%) on radiographs taken at 1 year postoperatively and continued to deteriorate at the latest follow-up.

CONCLUSIONS

In this specific cohort of patients, the increased rate of femoral stem aseptic loosening was implant-related and was attributed only to a specific type of femoral stem (Quadra-S). No relation to other factors was proven suggesting that the surface characteristics of this femoral stem and the lack of bioactive coating are responsible for the observed early femoral failures. These findings should be confirmed by additional registry work and larger population sample sizes are needed to evaluate the prosthesis performance after implantation through the DAA.

Subsidence of a metaphyseal-anchored press-fit stem after 4-year follow-up: an EBRA-FCA analysis

PURPOSE

Uncemented stem migration analysis by EBRA-FCA (Einzel-Bild-Roentgen Analyse, Femoral Component Analyse) has been seen to be a good predictive indicator for early implant failure. In this study, we investigated the migration behavior of a cementless metaphyseal-anchored press-fit stem after 4-year follow-up.

METHODS

Applying a retrospective study design, we reviewed all consecutive patients who between 2012 and 2017 received a cementless Accolade II press-fit stem at our Department. We reviewed medical histories and performed radiological measurements using EBRA-FCA software. EBRA-FCA measurements and statistical investigations were performed by two independent investigators.

RESULTS

A total of 102 stems in 91 patients (female 60; male 31) fulfilled our inclusion criteria. Mean age at surgery was 66.2 (range 24.3-92.6) years. EBRA migration analysis showed a mean subsidence of 1.4 mm (range 0.0-12.0) at final follow-up. The angle between stem and femur axis was 0.5° (range 0.0°-2.8°) after 48 months. No correlations between gender or Dorr types and subsidence were found (p > 0.05). A body mass index > 30 kg/m² showed a significant increase in stem subsidence within the first 6 (p = 0.0258) and 12 months (p = 0.0466) postoperative.

CONCLUSIONS

Migration pattern of the metaphyseal-anchored stem and a low subsidence rate at final follow-up may predict a good long-term clinical result.

TRIAL REGISTRATION

Number: 20181024-1875.

Does a Monoblock Acetabular Component With a Ceramic Liner Cause More Pelvic Bone Loss Than a Conventional Modular Cementless Acetabular Component? A 2-Year Randomized Clinical Trial

BACKGROUND

Ceramic-on-ceramic bearings permit the use of large femoral head size while maintaining a favorable effect on wear rates. However, because of increased device rigidity, periprosthetic bone quality could be negatively affected due to stress shielding. The purpose of this study is to assess pelvic periprosthetic bone remodeling around a monoblock ceramic-on-ceramic acetabular component compared to that around a conventional modular metal-on-polyethylene device.

METHODS

Participants were randomized to receive hip replacement using either a porous-coated, modular metal-on-polyethylene acetabular component (n = 46) or a hydroxyapatite and titanium-coated monoblock shell with an integrated ceramic-on-ceramic bearing (n = 40). Radiographic assessments were completed preoperatively and postoperatively, and measurements of bone mineral density (BMD) using dual-energy X-ray absorptiometry with region free analysis were performed postoperatively and over 2-years of follow-up.

RESULTS

There was no significant difference in BMD between the 2 groups at baseline or over the following 2 years. At follow-up, complete shell-to-bone contact without a radiolucent line was observed in 26 (67%) of the modular devices and in 37 (93%) of monoblock (P < .001). The modular device was an independent predictor of radiolucent lines (odds ratio 19.1, P = .007). No cases underwent revision surgery for acetabular loosening.

CONCLUSION

Both the porous-coated modular and hydroxyapatite-coated monoblock acetabular components showed successful clinical results at short-term follow-up with no difference in pixel-level BMD. Using a large head monoblock device does not appear to be associated with an adverse effect on the local bone environment when compared to a modular device. NCT: NCT01558752.

Preliminary outcomes of the cementless UNITED hip system for primary total hip arthroplasty at a minimum 2-year follow-up

INTRODUCTION

This study aimed to report the initial results of the cementless UNITED hip system in primary total hip arthroplasty (THA) with a minimum follow-up of 2 years.

METHODS

We retrospectively studied a consecutive series of 203 cementless THAs in 180 patients operated between 2015-2017. We included 89 female and 91 male patients with a mean age of 67 (28 to 89) years. The mean follow-up was 40 (29 to 62) months. Clinical outcome scores and radiographs were measured. Survival was calculated defining failure as the need for any further femoral or acetabular revision, irrespective of the reason.

RESULTS

No femoral component loosening was detected. One patient had a Vancouver-B1 intraoperative periprosthetic femoral fracture treated with implant retention and cerclage wires. Two acetabular components were revised for aseptic loosening. Three patients suffered an acute infection treated with debridement, antibiotics, and implant retention. The mean Merle d'Aubigné et Postel scores improved from 13 (4 to 16) points preoperatively to 17 (12 to 18) points at the latest follow-up (p < 0.001). At a mean time of 40 months of follow-up, the survival was 99% and 100% for the acetabular and the femoral components, respectively.

CONCLUSION

This cementless design showed excellent preliminary outcomes in terms of fixation and patient satisfaction, comparable to that of other well-known similar systems.

Minimum 10 years clinical results of an anatomical short stem with a proximal hydroxyapatite coating

OBJECTIVES

The CentPillar stem (Stryker Orthopaedics), an anatomical short stem, was designed to match the proximal femoral canal shape in both patients with normal hips and those with developmental dysplasia of the hip (DDH). The long-term outcomes of the CentPillar stem was examined herein.

METHODS

In total, 222 hips that underwent total hip arthroplasty using the CentPillar stem were analyzed. DDH was the main reason for surgery (79.3%). Implant survivorship was assessed using Kaplan-Meier analysis. For radiographic evaluation, stress shielding was assessed using the Engh classification. For functional evaluation, patients' ability to perform deep hip bending activities (sit on the floor, squat, and sit straight) was assessed.

RESULTS

During a median follow-up of 13.1 years, 2 stem revisions were performed (aseptic loosening and late hematogenous periprosthetic infection), and the overall cumulative implant survival rate was 99.0% at 15 years. In the radiographic evaluation, grade >3 stress shielding was found in only one hip. More than 80% of the patients were able to perform each of the three deep hip bending activities.

CONCLUSIONS

Good fixation at the proximal part of the femur was obtained, and the implant survival rate of the CentPillar stem was excellent during a long-term follow-up.

Outcomes with Two Tapered Wedge Femoral Stems in Total Hip Arthroplasty Using an Anterior Approach

Background

The majority of hip arthroplasties in the United States utilize cementless acetabular and femoral components. Despite their similarities, stem geometry can still differ. The purpose of this study is to compare the clinical results of two wedge-type stem designs.

Methods

A retrospective study of patients who underwent primary THA utilizing a direct anterior approach between January 2016 and January 2017. Two cohorts were established based on femoral stem design implanted. Descriptive patient characteristics and surgical and clinical data was extracted which included surgical time, length of stay (LOS), presence of pain (categorized as groin, hip, or thigh pain) at the latest follow-up, and revisions. Immediate postoperative radiographs were compared with the latest follow-up radiographs to assess limb length discrepancies, stem alignment, and stem subsidence.

Results

A total of 544 patients were included. 297 patients received the Group A stem (morphometric) and 247 patients received the Group B stem (flat-tapered). A significantly higher proportion of Group B stems subsided ≥3 mm and were in varus alignment than the Group A design. Additionally, a significantly greater number of patients who received the Group B stem reported postoperative hip and thigh pain. The logistic regression found that the Group B stem was 2.32 times more likely to subside ≥3 mm than the Group A stem.

Conclusion

Our study suggests modestly improved radiographic and clinical outcomes and fewer instances of thigh pain, subsidence, and varus alignment in the patients who received the Group Ahip stem. Further studies are warranted to assess long-term significance.

Inadequate Metadiaphyseal Fill of a Modern Taper-Wedge Stem Increases Subsidence and Risk of Aseptic Loosening: Technique and Distal Canal Fill Matter!

BACKGROUND

Adequate interference fit and mechanical stability through optimal surgical technique are essential to prevent subsidence and loosening in cementless total hip arthroplasty. The purpose of this study is to determine the effect of surgical technique on radiographic subsidence and subsequent stability of a modern taper-wedge cementless stem.

METHODS

A retrospective review of 250 consecutive cementless primary total hip arthroplasties performed by 2 surgeons was completed. Surgeon A vigorously broached, maximizing the mediolateral stem dimension and confirmed final broach stability with a torsional test, whereas Surgeon B did not. All patients received identical taper-wedge stems. Preoperative bone morphology (canal flare index), postoperative subsidence, and canal fill were radiographically assessed.

RESULTS

Canal flare index was not different between groups (P = .747). There was significantly less subsidence at 1 month for Surgeon A (0.3 vs 1.3 mm, P < .001). Additional subsidence at 1 year occurred in only 0.8% of Surgeon A (1/119) compared to 51.6% of Surgeon B stems (33/64, P < .001). Surgeon technique and canal fill measured at 60 mm below the lesser trochanter were the only variables predictive for subsidence, where Surgeon A and B had a mean canal fill of 95% and 86%, respectively. Surgeon B had 2 cases of aseptic loosening (2%) at 2 and 3 years postoperatively.

CONCLUSION

These observations support that maximizing mediolateral canal fill and avoiding under-sizing the femoral implant with meticulous broaching technique minimizes subsidence and optimizes stability of modern cementless taper-wedge stems. Failure to optimize canal fill with appropriate broaching and surgical technique may predispose femoral components to failure from aseptic loosening.

Early femoral component migration: comparing the anterior and posterior approach to the hip

PURPOSE

Early femoral component migration is a useful indicator for identifying implants at risk of failure due to aseptic loosening. The goal of this retrospective study was to identify if anterior approach (AA) treated hips are at a higher risk of failure due to aseptic loosening caused by early migration compared to hips operated on using the traditional posterior approach (PA).

METHODS

A total of 388 hips were included in this study, 139 AA and 249 PA treated hips. Femoral component migration was evaluated using EBRA-FCA and radiographs were assessed for radiolucency at latest follow-up. Preoperative and 2-year clinical outcomes were reported.

RESULTS

The 1- and 2-year migration rates (mm/year), and total migration (mm) at 2-year follow-up were comparable between AA and PA hips, respectively: 0.52 versus 0.41, 0.18 versus 0.19, and 0.64 versus 0.63 (all p > 0.05). Though not statistically significant, a higher percentage of AA hips passed 2-year total migration thresholds that have been associated with aseptic loosening compared to PA hips: 25.4% versus 16.5% for 1.5 mm threshold, and 11.3% versus 4.1% for the 2.7 mm threshold. Migration was not associated with the presence of radiolucent lines. All clinical outcomes improved significantly between preoperative and 2-year follow-up.

CONCLUSIONS

There was no association between the AA and any significant increase in femoral component migration. A higher percentage of AA hips exceeded the migration thresholds associated aseptic loosening; however, these stems had no other indications of instability and therefore suggests that this may be a difference in migration pattern.

Variation in greater trochanteric lateroversion: a risk factor for femoral stem varus in total hip arthroplasty

INTRODUCTION

Correct implant positioning is required to achieve adequate biomechanics. The greater trochanter is more medially or laterally positioned in some patients, known as trochanteric lateroversion. However, studies have not identified correlations between postoperative coronal alignment and variation in greater trochanteric lateroversion. The purpose of this study was to identify the effects of variation in greater trochanteric lateroversion on postoperative stem coronal alignment and to investigate other factors related to stem coronal alignment.

METHODS

A total of 213 hips in 149 patients who underwent total hip arthroplasty were included in this prospective study. The greater trochanters were categorised into 5 groups according to the degree of variation in greater trochanteric lateroversion, and the stem coronal alignment angle and stem fit were measured on anteroposterior radiographs.

RESULTS

Postoperative stem varus was positively correlated with greater trochanteric lateroversion (r = 0.26065, p = 0.0001) and negatively correlated with the stem fit (r = -0.16568, p = 0.0155).

DISCUSSION

Excessive variation in greater trochanteric lateroversion was a risk factor for femoral stem varus, and the stem varus position was always accompanied by inadequate canal filling. When the tip of the trochanteric overhang exceeded the centreline of the femoral canal, the influence of lateroversion of the greater trochanter on the femoral stem remarkably increased. Appropriate measures should be implemented to avoid a stem varus position and inappropriate stem fit.

Minimum 15-Year Results of a Dual-Offset Uncemented Femoral Stem in Total Hip Arthroplasty

BACKGROUND

The aim of the present study is to assess the long-term clinical and radiological outcomes of a proximal porous-coated, dual-offset, tapered titanium alloy uncemented stem at a minimum of 15 years of follow-up.

METHODS

We reviewed 210 total hip arthroplasties (in 193 patients) performed between 1996 and 1999 and followed prospectively in our database who received the Synergy stem. We report a Kaplan-Meier survival analysis as well as the Harris Hip Score, the Western Ontario and McMaster University Arthritis Index, and the Short Form Health Survey-12 scores. Radiographs were evaluated for evidence of subsidence, osteolysis, osteointegration, or loosening.

RESULTS

The average follow-up was 16 years (range, 15-17.7 years). Kaplan-Meier survival analysis with revision of stem for aseptic mechanical loosening (1 stem) as the end point revealed a cumulative survival rate of 99.5% at 16 years. The Harris Hip Score, the Western Ontario and McMaster University Arthritis Index, and the Short Form Health Survey-12 physical scores were all significantly improved (P < .001) from the preoperative period to latest follow-up. Minor osteolysis was observed proximally in 14 hips (6.6%) with no osteolysis distal to the porous coating.

CONCLUSION

To our knowledge, this study represents the largest series reporting the longest clinical follow-up of this third-generation, dual-offset, proximal ingrowth, tapered cementless stem. The Synergy stem design has achieved excellent clinical outcomes, predictable osteointegration, and outstanding survivorship of 99.5% at a minimum of 15 years follow-up, representing the standard for femoral stems at our institution.

The Accolade TMZF stem fulfils the demands of modern stem design: Minimum 5-year survival in a cohort of 937 patients

PURPOSE

Modern hip stem design includes a prosthesis that has a predictable outcome in all total hip arthroplasty (THA) patients, regardless of approach, surgeon or patient characteristics. Introduction without a learning curve and, in cases of problems, the possibility for a simple revision are other prerequisites. The purpose of this study is to evaluate whether the Accolade TMZF stem (Stryker Orthopedics, Mahwah, New Jersey, USA) is suitable to fulfil these demands. We report our mid-term survival of the Accolade TMZF hip stem in all patients from the first implantation at our institute.

METHODS

From the start of using the Accolade TMZF stem (March 2009) until February 2011, 937 THA were performed by 12 surgeons using a posterolateral or anterolateral approach. Survival of the stem was calculated using Kaplan-Meier analysis. Effect of approach, patient age and comorbidity were analysed with a Cox proportional hazards' model. The learning effect was determined by comparing the number of revisions in the surgeons' first 20 THAs with their next 30 THAs and the subsequent THAs.

RESULTS

At 5 years, cumulative stem survival was 97.9% based on revisions for all reasons and 98.8% with aseptic loosening as endpoint. We found no effect of surgical approach, patient age or comorbidity on stem survival. No learning effect was found.

CONCLUSION

The Accolade TMZF stem fulfilled the demands of modern stem design.

Total hip arthroplasty with accolade/trident through the direct minimally invasive anterior approach without traction table: Learning curve and results after a minimum of 5 years

BACKGROUND

The direct minimally invasive anterior approach (DMIAA) in total hip arthroplasty (THA) is widely accepted. In our department the DMIAA according to Rachbauer together with the Trident cup and Accolade stem was introduced in 2004. The purpose of the study was to demonstrate the five-year results and to analyze the learning curve of a new introduced approach.

PATIENTS AND METHODS

Between July 2004 and May 2006, a consecutive series of 151 THA in 147 patients was retrospectively analyzed. All patients were planned to received a THA with the Accolade/Trident implant system using the DMIAA without traction table. Clinical and radiographic data, complications and survivorship were documented with a follow-up of at least 5 years.

RESULTS

Regarding cup implantation, there were 11 (7.3%) failed intentions to treat due to missing pressfit (8 cases) and acetabular floor perforation (3 cases). No failed intentions to treat occurred during stem implantation. Total implant survival after 5 years follow-up after exclusion of 11 cases with failed intention to treat (N=140) was 96.9% (SD 1.4; CI 94.3-99.6). After exclusion of the failed intentions to treat (N=140, N=4 in the first 20 cases), there was significant (p<0.001) difference between the first 16 implants with a 5 year-survival of 83.2% (SD 8.6; CI 66.4-100) and 95.7% (SD 0.9; CI 93.9-97.5) for the following 124 implants. Radiolucent lines were observed in Gruen zone 1 in 3.3% and in Gruen zone 1 and 2 in 1.1%.

DISCUSSION

THA with Accolade/Trident using the DMIAA without traction table according to Rachbauer temporary exposed patients to a higher risk of implant revisions, which was normalized after the first 20 cases. Results of the learning curve are comparable to other techniques using an orthopaedic traction table. After the typical learning curve, the rate of 5 years implant failure is in accordance with the registry data for non-cemented implants. The Accolade stem showed minimal radiographic signs of radiolucency.

LEVEL OF EVIDENCE

IV, retrospective, consecutive case series.

Effect of Denosumab on Femoral Periprosthetic BMD and Early Femoral Stem Subsidence in Postmenopausal Women Undergoing Cementless Total Hip Arthroplasty

Antiresorptive denosumab is known to improve the quality and strength of cortical bone in the proximal femurs of osteoporotic women, but its efficacy in preventing periprosthetic bone loss and reducing femoral stem migration has not been studied in women undergoing cementless total hip arthroplasty. We conducted a single-center, randomized, double-blinded, placebo-controlled trial of 65 postmenopausal women with primary hip osteoarthritis and Dorr type A or B proximal femur anatomy. The patients randomly received subcutaneous injections of denosumab 60 mg or placebo once every 6 months for 12 months, starting 1 month before surgery. The primary endpoint was the change in bone mineral density (BMD) of the proximal femur (Gruen zone 7) at week 48, and the secondary endpoint was stem subsidence measured by radiostereometric analysis (RSA) at week 48. Exploratory endpoints included changes in BMDs of the contralateral hip, lumbar spine and distal radius, serum levels of bone turnover markers, walking speed, walking activity, patient-reported outcome measures, and radiographic assessment of stem osseointegration. The participants underwent vertebral-fracture assessment in an extension safety study at 3 years. Denosumab significantly decreased bone loss in the medial femoral neck (zone 7) and increased periprosthetic BMD in the greater trochanteric region (zone 1) and lesser trochanteric region (zone 6). Denosumab did not reduce temporary femoral stem migration. The migration occurred mainly during the settling period (0 to 12 weeks) after implantation of the prosthesis. All of the stems osseointegrated, as evaluated by RSA and radiographs. There were no intergroup differences in functional recovery. Discontinuation of denosumab did not lead to any adverse events. In conclusion, denosumab increased periprosthetic BMD in the clinically relevant regions of the proximal femur, but the treatment response was not associated with any reduction of initial stem migration. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of the American Society for Bone and Mineral Research.

Good stability of a cementless, anatomically designed femoral stem in aging women: a 9-year RSA study of 32 patients

Background and purpose - We previously reported a transient, bone mineral density (BMD)-dependent early migration of anatomically designed hydroxyapatite-coated femoral stems with ceramic-ceramic bearing surfaces (ABG-II) in aging osteoarthritic women undergoing cementless total hip arthroplasty. To evaluate the clinical significance of the finding, we performed a follow-up study for repeated radiostereometric analysis (RSA) 9 years after surgery. Patients and methods - Of the 53 female patients examined at 2 years post-surgery in the original study, 32 were able to undergo repeated RSA of femoral stem migration at a median of 9 years (7.8-9.3) after surgery. Standard hip radiographs were obtained, and the subjects completed the Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index outcome questionnaires. Results - Paired comparisons revealed no statistically significant migration of the femoral stems between 2 and 9 years post-surgery. 1 patient exhibited minor but progressive RSA stem migration. All radiographs exhibited uniform stem osseointegration. No stem was revised for mechanical loosening. The clinical outcome scores were similar between 2 and 9 years post-surgery. Interpretation - Despite the BMD-related early migration observed during the first 3 postoperative months, the anatomically designed femoral stems in aging women are osseointegrated, as evaluated by RSA and radiographs, and exhibit good clinical function at 9 years.

A long-lasting bisphosphonate partially protects periprosthetic bone, but does not enhance initial stability of uncemented femoral stems: A randomized placebo-controlled trial of women undergoing total hip arthroplasty

Low bone quality may compromise the success of cementless total hip arthroplasty in high-risk patients such as elderly women. Zoledronic acid is a long-lasting antiresorptive agent, which is known to reduce short-term periprosthetic bone loss. However, its effect on femoral stem stability is not well known. Forty-nine female patients with a mean age of 68 years (range, 51-85 years) scheduled to undergo cementless total hip arthroplasty due to osteoarthritis were randomized in this double-blind, placebo-controlled trial to receive a single postoperative infusion of zoledronic acid or placebo. Patients were evaluated for up to four years postoperatively for femoral stem migration measured by radiostereometric analysis, bone mineral density (BMD) measured by dual X-ray absorptiometry, functional recovery, and patient-reported outcome scores. Implant survival was determined at nine years postoperatively. Zoledronic acid did not reduce the femoral stem migration that occurred predominantly during the settling period of the first 3-6 months. Subsequently, all femoral stems were radiographically osseointegrated. Zoledronic acid maintained periprosthetic BMD, while the expected loss of periprosthetic bone during the first 12 months was found in controls. Thereafter, periprosthetic BMD of Gruen zone 7 decreased even in the zoledronic acid group but remained 14.6% higher than that in the placebo group at four years postoperatively. Functional recovery was comparable across the groups. At nine years postoperatively, no revision arthroplasty had been performed. In conclusion, in women at high-risk for low BMD, zoledronic acid had a long-lasting, partially protective effect on periprosthetic bone loss, but the treatment did not enhance the initial femoral stem stability.

Outcomes using wedge stem with full hydroxiapatite coverage with a minimum of 5 years' follow-up

INTRODUCTION

Total Hip Arthroplsty (THA) using uncemented stems is a popular practice in the last decades. The implant survivorship is crtitical and a less than 10% revision at 10 years is been propesed for commercialization and use.

OBJECTIVE

To analyse the clinicoradiological results of an uncemented hydroxiapatite covered wedge stem with a 5 years minimum follow up.

MATERIAL AND METHODS

Prospective study, patients aged from 21-75years were included. All patients received an Element stem (Exactech) and uncemented cup with crosslink poly and 32 mm metal head, and posterior approach with piriformis retention was used. Scheduled clinical and radiographic evaluation at 3 weeks, 3-6 month, year and subsequent years using Harris Hip Score and Merle d'Aubigné Postel. Intraoperative and during follow up complications were recorded.

RESULTS

One hundred and fourteen total hip replacements in 104 patients: 54 females and 50 males (52%/48%). Follow-up of 5.7 years (range, 5-6.2years). Average age 56.8years (range, 42-75years). Clinical evaluation the Merle d'Aubigné score improved 6.8 points and from the initianl Harris Hip Score 47.3 to 93.1 points at last follow up. Radiographic evaluation shows osteointegration in all stems. And in 6 cases (5.3% at 3 months subsidence was detected, average 1.4 mm (range 0-2.6 mm) with no clinical manifestation, 3 cases of subsidence were associated to intraoperative fractures (1 greater trochanter and 2 in the calcar area, all resolved with wire cerclaje). Subjective evaluation: 86 cases (82.6%) excellent, 9 patients (8.6%) good, 6 cases (5.9%) satisfactory and 3 cases (2.9%) poor. All poor results linked to the intraoperative complications. No patient lost during follow up period. No femoral pain dislocation or aseptic or loosening detected. All implants were in situ at last follow up.

CONCLUSIONS

The radiological results confirm the benefits of this type of stem with good osteointegration. The clinical and subjective results are promising. With good surgical technical and without complications the risk of aseptic loosening should be absent or minimal.

Cementless Tapered Wedge Femoral Stems Decrease Subsidence in Obese Patients Compared to Traditional Fit-and-Fill Stems

BACKGROUND

Femoral component stability and resistance to subsidence is critical for osseointegration and clinical success in cementless total hip arthroplasty. The purpose of this study was to radiographically evaluate the anatomic fit and subsidence of 2 different proximally tapered, porous-coated modern cementless femoral component designs.

METHODS

A retrospective cohort study of 126 consecutive cementless total hip arthroplasties was performed. Traditional fit-and-fill stems were implanted in the first 61 hips with the remaining 65 receiving morphometric tapered wedge stems. Preoperative bone morphology was radiographically assessed by the canal flare index. Canal fill in the coronal plane, subsidence, and the sagittal alignment of stems was measured digitally on immediate and 1-month postoperative radiographs.

RESULTS

Demographics and canal flare indices were similar between groups. The percentage of femoral canal fill was greater in the tapered wedge compared to the fit-and-fill stem (P = .001). There was significantly less subsidence in the tapered wedge design (0.3 mm) compared to the fit-and-fill design (1.1 mm) (P = .001). Subsidence significantly increased as body mass index (BMI) increased in the fit-and-fill stems, a finding not observed in the tapered wedge design (P = .013).

CONCLUSION

An anatomically designed morphometric tapered wedge femoral stem demonstrated greater axial stability and decreased subsidence with increasing BMI than a traditional fit-and-fill stem. The resistance to subsidence, irrespective of BMI, is likely due to the inherent axial stability of a tapered wedge design and may be the optimal stem design for obese patients.

Acoustic pattern evaluation during cementless hip arthroplasty surgery may be a new method for predicting complications

BACKGROUND

Although surgeons must perform implantation of the cementless stem during total hip arthroplasty (THA) without complications, assessment is left to the surgeon's intuitive judgement, which could contain inter/intra-observer bias variety. We therefore asked (1) whether the sound created during the stem implantation could be evaluated objectively and (2) whether those sounds are correlate to the complication specific to the cementless stems. Our hypothesis is that the sounds produced during stem insertion could be quantified and related to the complications.

PATIENTS AND METHOD

In 71 THAs, we quantified the sound produced during stem insertion and investigated the relationship between these sounds and the occurrence of intraoperative fracture and subsidence.

RESULTS

The sound data were divided into two patterns: Patterns A and B. The difference between the peak value (dB) at the most common frequency (near 7 kHz) and the second most common frequency (near 4 kHz) of strikes during the final phase of implantation in Patterns A and B showed a significant difference. Adverse events on intraoperative fracture and subsidence were significantly less common in patients with Pattern A than in those with Pattern B (six of 42 hips with Pattern A and 13 of 29 hips with Pattern B, p = 0.004). Pattern A in predicting a clinical course without those adverse events was 69.2% and the specificity was 68.4%. Positive and negative predictive values were 85.7% and 44.8%, respectively.

CONCLUSION

The sound generated during stem insertion was quantified. Those sound patterns were associated with complications.

Distal femoral cortical hypertrophy after hip arthroplasty using a cementless doubletapered femoral stem

PURPOSE

To review 437 hips in 404 patients who underwent total hip arthroplasty (THA) or hemiarthroplasty using the Accolade TMZF stem to determine the incidence and risk factors of distal femoral cortical hypertrophy (DFCH).

METHODS

Records of 437 hips in 169 men and 235 women aged 26 to 100 (mean, 65.7) years who underwent THA (n=293) or hemiarthroplasty (n=144) using the Accolade TMZF femoral stem by 2 senior surgeons and were followed up for a mean of 54.7 months were reviewed. Clinical outcome was assessed using the modified Harris Hip Score and visual analogue score for pain. Proximal femoral geometry and canal flare index were assessed on preoperative radiographs, and DFCH, stem position, subsidence, loosening, and stress shielding were assessed on postoperative radiographs according to the Gruen zone.

RESULTS

Of 437 hips, 27 (6.2%) developed DFCH and 410 did not. Hips with DFCH had a higher incidence of thigh pain (18.5% vs. 2.2%, p<0.001) and earlier onset of thigh pain (12.3 vs. 20.8 months, p=0.015), compared with those without. Nonetheless, all femoral stems were well-fixed, and no osteolysis or loosening was detected. The 2 groups achieved comparable clinical outcome in terms of Harris Hip Score and pain. The mean canal flare index was higher in hips with than without DFCH (3.706 vs. 3.294, p=0.002). The mean vertical subsidence of the femoral stem was lower in hips with than without DFCH (1.5 vs. 3.4 mmp<0.001). Subsidence negatively correlated with the canal flare index (correlation coefficient= -0.110, p=0.022). The incidence of the DFCH increased with each unit of increment in canal flare index (odds ratio [OR]=1.828, p=0.043) and each year younger in age (OR=0.968, p=0.015).

CONCLUSION

The incidence of DFCH in hips withthe Accolade TMZF stem was 6.2%. Patients with a higher canal flare index and younger age had a higher incidence of DFCH. Nonetheless, DFCH did not affect clinical outcome or femoral stem stability.

New Approach and Stem Increased Femoral Revision Rate in Total Hip Arthroplasty

This study compared the femoral stem revision and loosening rates in primary total hip arthroplasty between 2 different approaches and stem designs. Recent reports comparing the direct anterior approach with either the posterior or lateral approach showed that patients undergoing the direct anterior approach have less pain and an accelerated functional recovery in the early postoperative period. After converting to an anterior approach, the authors observed an increased rate of femoral stem revision. From 2003 to 2009, a posterior or lateral approach was used to insert 514 stems of 2 designs. These cases included the use of an extensively coated cobalt-chrome stem (n=232) or a straight, dual-tapered, proximally porous-coated titanium stem (n=282). In the following years, from 2009 to 2012, 594 short, proximally coated, titanium tapered-wedge stems were inserted through a direct anterior approach. The revision rates of femoral stems inserted through a posterior approach or a lateral approach were compared with those inserted via a direct anterior approach. No stem revisions occurred in the posterior approach group or the lateral approach group, and 5 stems were revised in the anterior approach group for periprosthetic fracture or aseptic loosening (0.8%). Significantly more stem revisions occurred after the use of the new stem design and a direct anterior approach (P=.04).

Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem

OBJECTIVES

In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes.

PATIENTS AND METHODS

We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject-specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year.

RESULTS

Stovepipe models implanted with large-size stems had significantly lower equivalent stress on the proximal-medial area of the femur compared with champagne-flute and intermediate models, with a significant loss of BMD in the corresponding area at one year post-operatively.

CONCLUSIONS

The stovepipe femurs required a large-size stem to obtain an optimal fit of the stem. The FEA result and post-operative BMD change of the femur suggest that the combination of a large-size Accolade TMZF stem and stovepipe femur may be associated with proximal stress shielding.Cite this article: M. Oba, Y. Inaba, N. Kobayashi, H. Ike, T. Tezuka, T. Saito. Effect of femoral canal shape on mechanical stress distribution and adaptive bone remodelling around a cementless tapered-wedge stem. Bone Joint Res 2016;5:362-369. DOI: 10.1302/2046-3758.59.2000525.

Prospective evaluation of short and mid-term outcomes of total hip arthroplasty using the Accolade™ stem

PURPOSE

Cementless press-fit total hip arthroplasty (THA) with the Accolade stem (Stryker AccoladeTM TMZF, Mahwah, New Jersey) has demonstrated variable implant survivorship and outcomes. The purpose of this study was to analyse the: 1) implant survivorship; 2) complications; 3) functional outcomes; 4) overall quality of life; and 5) patient expectations and satisfaction following THA with this particular press-fit stem.

METHODS

A prospectively collected database of 222 patients who underwent THA at 7 institutions between 2006 and 2009 using the Accolade stem (Stryker Inc. Mahwah, New Jersey) was evaluated. Harris Hip Score (HHS) and SF-12 were used to assess the outcomes at 2- and 5-year follow-up. Kaplan-Meier survivorship was calculated at 5 years of follow-up.

RESULTS

The 5-year aseptic and all-cause survivorship rates were 99.4% (95% CI, 96.3 to 99.9%) and 97.9% (95% CI, 94.6 to 99.2%), respectively. At 2 and 5 years postoperatively, the patients demonstrated a mean HHS of approximately 89 points and 92 points, respectively. The mental and physical components of the SF-12 mean score increased with the physical component having a more marked increase. The mental and physical components of the SF-12 score increased to a mean of 46 and 45 points at 2 and 5 years, respectively. At 2-year follow-up, over 90% of patients were satisfied with their outcome in a majority of areas surveyed.

DISCUSSION

Our results suggest that the use of this press-fit construct results in tremendous improvements in functional and quality of life outcomes, along with excellent survivorship at short- and mid-term follow-up.

Early Migration Predicts Aseptic Loosening of Cementless Femoral Stems: A Long-term Study

BACKGROUND

Excessive early migration of cemented stems and cups after THA has been associated with poor long-term survival and allows predictable evaluation of implant performance. However, there are few data regarding the relationship between early migration and aseptic loosening of cementless femoral components, and whether early migration might predict late failure has not been evaluated, to our knowledge. Einzel-Bild-Röntgen-Analyse-femoral component analysis (EBRA-FCA) is a validated technique to accurately measure axial femoral stem migration without the need for tantalum markers, can be performed retrospectively, and may be a suitable tool to identify poor performing implants before their widespread use.

QUESTIONS/PURPOSES

We asked: (1) Is axial migration within the first 24 months as assessed by EBRA-FCA greater among cementless stems that develop aseptic loosening than those that remain well fixed through the second decade; (2) what is the diagnostic performance of implant migration at 24 months postoperatively to predict later aseptic loosening of these components; and (3) how does long-term stem survivorship compare between groups with high and low early migration?

METHODS

We evaluated early axial stem migration in 158 cementless THAs using EBRA-FCA. The EBRA-FCA measurements were performed during the first week postoperatively (baseline measurement) and at regular followups of 3, 6, and 12 months postoperatively and annually thereafter. The mean duration of followup was 21 years (range, 18-24 years). The stems studied represented 45% (158 of 354) of the cementless THAs performed during that time, and cementless THAs represented 34% (354 of 1038) of the THA practice during that period. No patient enrolled in this study was lost to followup. Multivariate survivorship analysis using Cox's regression model was performed with an endpoint of aseptic loosening of the femoral component. Loosening was defined according to the criteria described by Engh et al. and assessed by two independent observers. Patients with a diagnosis of prosthetic joint infection were excluded. Receiver operating characteristic (ROC) curve analysis was used to evaluate diagnostic performance of axial stem migration 1, 2, 3, and 4 years postoperatively as a predictor of aseptic loosening. Survivorship of hips with high (≥ 2.7 mm) and low (< 2.7 mm) migration was compared using a competing-events analysis.

RESULTS

Femoral components that had aseptic loosening develop showed greater mean distal migration at 24 months postoperatively than did components that remained well fixed throughout the surveillance period (4.2 mm ± 3.1 mm vs 0.8 mm ± 0.9 mm; mean difference, 3.4 mm, 95% CI, 2.5-4.4; p ≤ 0.001). Distal migration at 24 months postoperatively was a strong risk factor for aseptic loosening (hazard ratio, 1.98; 95% CI, 1.51-2.57; p < 0.001). The associated overall diagnostic performance of 2-year distal migration for predicting aseptic loosening was good (area under the ROC curve, 0.86; 95% CI, 0.72-1.00; p < 0.001). Sensitivity of early migration measurement was high for the prediction of aseptic loosening during the first decade after surgery but decreased markedly thereafter. Stems with large amounts of early migration (≥ 2.7 mm) had lower 18-year survivorship than did stems with little early migration (29% [95% CI, 0%-62%] versus 95% [95% CI, 90%-100%] p < 0.001).

CONCLUSIONS

Early migration, as measured by EBRA-FCA at 2 years postoperatively, has good diagnostic capabilities for detection of uncemented femoral components at risk for aseptic loosening during the first and early second decades after surgery. However, there was no relationship between early migration patterns and aseptic loosening during the late second and third decades. EBRA-FCA can be used as a research tool to evaluate new cementless stems or in clinical practice to evaluate migration patterns in patients with painful femoral components.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Catastrophic Femoral Neck Failure after THA with the Accolade(®) I Stem in Three Patients

CASE DESCRIPTION

We report a series of three femoral stem failures, each occurring at the head-neck junction, with all patients experiencing limited and painful ambulation, leading to subsequent revision arthroplasty. All patients were male with high-offset femoral stems and increased head lengths, and each had undergone primary THA at a minimum of 7 years before presentation (average, 94 months). There were no associated deep infections or cases of aseptic loosening in the cohort.

LITERATURE REVIEW

There is a paucity of similar reports in the literature regarding femoral stem failure at the head-neck junction. When failures of titanium stems have been reported, failure has been attributed to material design and geometry, laser etching, overload, implant alignment, and patient characteristics.

PURPOSE AND CLINICAL RELEVANCE

Catastrophic failures of femoral stems at the head-neck junction are a rare cause for revision after THA. Component material and design, surgical technique, and patient factors may contribute.

Trade-off between stress shielding and initial stability on an anatomical cementless stem shortening: in-vitro biomechanical study

Shortened cementless femoral stems have become popular with the advent of minimally invasive total hip arthroplasty (THA). Successful THA requires initial stem stability and prevention of stress shielding-mediated bone loss, although the effect of stem shortening is controversial. Here we experimentally examined whether stem shortening affects stress shielding and initial stability. Anatomical stems (length, 120 mm) were cut to an 80 mm or 50 mm length. Ten tri-axial strain gauges measured the cortical strain on each stem-implanted femur to evaluate stress shielding. Two transducers measured axial relative displacement and rotation under single-leg stance loading. The 50 mm stem increased the equivalent strains with respect to the original stem in the proximal calcar region (31.0% relative to intact strain), proximal medial region (63.1%), and proximal lateral region (53.9%). In contrast, axial displacement and rotation increased with a decreasing stem length. However, the axial displacement of the 50 mm stem was below a critical value of 150 µm for bone ingrowth. Our findings indicate that, with regard to a reduction in stem length, there is a tradeoff between stress shielding and initial stability. Shortening the stem up to 50 mm can promote proximal load transfer, but bone loss would be inevitable, even with sufficient initial stability for long-term fixation.

Catastrophic Head-Neck Dissociation of a Modular Cementless Femoral Component

CASE

We report two cases of modular head-neck junction failure involving the Stryker Accolade TMZF stem leading to sudden dissociation of the femoral head from the stem. Both patients presented with mechanical symptoms in the hip followed by pain and hip dysfunction. Disassembly of the head and deformation of the male taper were seen on preoperative radiographs. Intraoperatively, both patients had substantial metallosis with a markedly damaged taper requiring stem revision.

CONCLUSION

We recommend regular clinical and radiographic surveillance of patients with the Stryker Accolade TMZF stem, especially those patients with pain and/or mechanical symptoms.

Do we need intraoperative radiographs for positioning the femoral component in total hip arthroplasty?

INTRODUCTION

Poor long-term results of total hip arthroplasty (THA) can result from femoral component misalignment. There are few reports that discuss the effectiveness of intraoperative radiographs for placing femoral components. This study is a retrospective review to find out the usefulness of intraoperative radiographs in detecting and improving the femoral component misalignment in posterior-approached primary THA.

MATERIALS AND METHODS

The study group included 150 primary THAs performed between September 2009 and April 2012. After the trial component insertion in lateral decubitus position, intraoperative radiography was performed. The surgeon assessed the femoral component position in three aspects: alignment, leg length, and offset. If it is not following the preoperative template, the surgeon makes the intraoperative adjustments to change the femoral component position. After the operation, postoperative radiograph was taken; the same parameters were measured and were compared to intraoperative findings. The changes in each parameter were classified into three categories: satisfactory, no change, and unsatisfactory. Among the three parameters, if one is satisfactory and the others are not unsatisfactory, we defined it as accurate positioning of the femoral component.

RESULTS

Intraoperative adjustments were made in 122 cases (81.3 %). The adjustments included changes in the component size (35.3 %), component alignment (38.6 %), femoral offset (14.0 %), and additional femoral neck cuts (56.0 %). As a result, accurate positioning was successfully achieved in 112 cases (91.8 %) by taking intraoperative radiographs.

CONCLUSION

Our data suggest that intraoperative radiography is a useful method for detecting the errors of placing the femoral components, and the success of a surgeon to correct those errors after detecting them intraoperatively.

The minimal invasive direct anterior approach in combination with large heads in total hip arthroplasty - is dislocation still a major issue? a case control study

Background

There have been increasing numbers of publications in recent years on minimally invasive surgery (MIS) for total hip arthroplasty (THA), reporting results with the use of different head sizes, tribologic and functional outcomes. This study presents the results and early complication rates after THA using the direct anterior approach (DAA) in combination with head sizes ≥ 36 mm.

Methods

A total of 113 patients with THA were included in the study. The Harris Hip Score (HHS) was determined, a radiographic evaluation was carried out, and complications were recorded. The minimum follow-up period was 2 years (means 35 ± 7 months).

Results

The HHS improved from 43.6 (± 12) to 88.2 (± 14; P < 0.01). One early infection occurred, one periprosthetic fracture, and three cases of aseptic stem loosening. No incorrect positioning of the implants was observed, and there were no dislocations.

Conclusion

THA with the minimally invasive DAA in combination with large heads is associated with good to very good functional results in the majority of cases. The complication rates are not increased. The rate of dislocation mainly as an complication of the first two years can be markedly reduced in particular.

Stro-1-positive BMSCs predict postoperative periprosthetic bone mineral density outcomes in uncemented total hip arthroplasty patients

Background

Bone marrow cell profiles are variable after total hip arthroplasty (THA), including variable levels of Stro-1⁺ and bone morphogenetic protein receptor (BMPRs)⁺ cells. We investigated the impact of bone marrow cell profiles on changes in periprosthetic bone mineral density (BMD) in uncemented THA patients.

Material/Methods

Bone marrow aspirates were collected from the metaphyseal region of discarded femoral heads from 24 consecutive THA patients (12 men and 12 women; mean age 66.7±11.0 years; range 52–87 years) treated from March 2009 to March 2011 at a single facility. Perioperative proportions of Stro-1⁺ and BMPR⁺ cells in femoral heads were assessed by flow cytometry. Follow-up examined the proximal femur Gruen zones R1 and R7 at 1 week and at 3, 6, and 12 months after THA, using dual-energy X-ray absorptiometry. Associations between BMD loss and age, gender, BMPRs⁺, and Stro-1⁺ were analyzed.

Results

At 3 months, R1 and R7 BMD decreased by 4.4% and 6.4%, respectively (P<0.05). At 12 months, the overall BMD decreases in R1 and R7 were 10.2% and 1%, respectively (P<0.05). Higher Stro-1⁺ cells proportion predicted R7 BMD increases at all time points (P<0.05) and R1 BMD increases at 6 and 12 months (P<0.05). BMPR1a⁺ proportion was associated with BMD increases at 6 months in the R1 region. BMPR2⁺ was not significantly associated with BMD (P>0.05).

Conclusions

Elevated Stro-1⁺ bone marrow cell profile may be a useful prognostic indicator for uncemented THA patients.

Prospective five-year subsidence analysis of a cementless fully hydroxyapatite-coated femoral hip arthroplasty component

Early subsidence >1.5 mm is considered to be a predictive factor for later aseptic loosening of the femoral component following total hip arthroplasty (THA). The aim of this study was to assess five-year subsidence rates of the cementless hydroxyapatite-coated twinSys stem (Mathys Ltd., Bettlach, Switzerland).This prospective single-surgeon series examined consecutive patients receiving a twinSys stem at Maria Middelares Hospital, Belgium. Patients aged >85 years or unable to come to follow-up were excluded. Subsidence was assessed using Ein Bild Roentgen Analyse--Femoral Component Analysis (EBRA-FCA). Additional clinical and radiographic assessments were performed. Follow-ups were prospectively scheduled at two, five, 12, 24, and 60 months.In total, 218 THA (211 patients) were included. At five years, mean subsidence was 0.66 mm (95% CI: 0.43-0.90). Of the 211 patients, 95.2% had an excellent or good Harris Hip Score. There were few radiological changes. Kaplan-Meier analysis indicated five-year stem survival to be 98.4% (95% CI: 97.6-100%).Subsidence levels of the twinSys femoral stem throughout the five years of follow-up were substantially lower than the 1.5 mm level predictive of aseptic loosening. This was reflected in the high five-year survival rate.

Radiographic Subsidence in Asymptomatic Patients After THR Using the Furlong Active HAP Stem

BACKGROUND

The short, tapered, collarless Furlong Active stem has been recently associated in the published literature with significant subsidence using Roentgen stereophotogrammetric analysis.

QUESTIONS/PURPOSES

The purpose of this study was to analyze the short-term radiographic subsidence in Furlong Active HAP stems and correlate the results with the age, gender, bone morphology, and bone quality of the proximal femur, stem diameter, and medullary canal filling.

METHODS

Sixty-five consecutive patients (70 hips) receiving the Furlong Active HAP stems were enrolled in this prospective series. The average follow-up was 2.99 ± 1.38 years. All patients were evaluated clinically using the Harris Hip Score (HHS) and radiographically for femoral stem subsidence. In addition, proximal femoral osteopenia, proximal femur morphology, and medullary canal filling were also evaluated.

RESULTS

The average subsidence was 2.4 mm (from 0 to 13 mm) at the end of the follow-up period. The average HHS score at the end of follow-up was 90 (range, 81-98). There was one intraoperative fracture.

CONCLUSIONS

Of the Furlong Active stems 61% subsided with initial weight bearing. Subsidence is higher in males, but no correlation has been found with age, stem diameter, morphology, osteopenia, or canal filling.

Coaxial PCL/PVA electrospun nanofibers: osseointegration enhancer and controlled drug release device

The failure of prosthesis after total joint replacement is mainly due to dysfunctional osseointegration and implant infection. There is a critical need for orthopedic implants that promote rapid osseointegration and prevent bacterial colonization, particularly when placed in bone compromised by disease or physiology of the patients. The aim of this study was to fabricate a novel coaxial electrospun polycaprolactone (PCL)/polyvinyl alcohol (PVA) core-sheath nanofiber (NF) blended with both hydroxyapatite nanorods (HA) and type I collagen (Col) (PCL(Col)/PVA(HA)). Doxycycline (Doxy) and dexamethasone (Dex) were successfully incorporated into the PCL(Col)/PVA(HA) NFs for controlled release. The morphology, surface hydrophilicity and mechanical properties of the PCL/PVA NF mats were analyzed by scanning electron microscopy, water contact angle and atomic force microscopy. The PCL(Col)/PVA(HA) NFs are biocompatible and enhance the adhesion and proliferation of murine pre-osteoblastic MC3T3 cells. The release of Doxy and Dex from coaxial PCL(Col)/PVA(HA) NFs showed more controlled release compared with the blended NFs. Using an ex vivo porcine bone implantation model we found that the PCL(Col)/PVA(HA) NFs bind firmly on the titanium rod surface and the NFs coating remained intact on the surface of titanium rods after pullout. No disruption or delamination was observed after the pullout test. These findings indicate that PCL(Col)/PVA(HA) NFs encapsulating drugs have great potential in enhancing implant osseointegration and preventing implant infection.