Stem subsidence after total hip revision: 183 cases at 5.9 years follow-up

Long-term Outcomes of Revision Total Hip Arthroplasty Using a Modular Fluted Conical Femoral Stem

BACKGROUND

This study presents minimum 6-year follow-up data on the survival and satisfaction of an uncemented modular revision femoral system, following on from our previously published earlier results.

METHODS

We retrospectively reviewed all revision hip arthroplasties performed at our institution between January 2005 and October 2012, using a single modular femoral revision system. Patient-reported outcomes were collected (satisfaction score and Oxford Hip Score). Preoperative and postoperative radiographs were reviewed for stem subsidence, and Kaplan-Meier analysis was performed for survival. A total of 115 femoral revisions were performed in 106 patients.

RESULTS

All-cause survival was 82% (95% confidence interval 74 to 91%) at 10.8 years, and 96% (95% confidence interval 90 to 100%) excluding septic failure. Of the 19 cases requiring reoperation, 16 were for infection, 2 for aseptic loosening, and 1 for mechanical failure. At final follow-up, 88.5% of patients were "satisfied" or "very satisfied".

CONCLUSIONS

This study showed excellent clinical results of a commonly used revision hip stem with at least 10 years follow-up. Satisfaction rates were high, with few aseptic failures. Stem subsidence was more common in revisions for infection, but did not correlate with lower satisfaction scores.

Retrospective survival analysis of the use of uncemented modular tapered stems for revision in periprosthetic Vancouver B-type fractures. Is instability a threat to survival?

INTRODUCTION AND OBJECTIVES

Periprosthetic hip fractures show increasing incidence and complexity, representing a challenge for the surgeon. We aimed to evaluate the survival of uncemented modular tapered stems in the treatment of periprosthetic Vancouver B2 and B3 type fractures and review the main complications and factors associated with decreased survival.

MATERIALS AND METHODS

We performed a retrospective study of patients submitted to revision arthroplasty for treatment of periprosthetic femoral stem Vancouver B2 and B3 type fractures with an uncemented modular fluted tapered stem (MRP-Titan). Demographic and radiographic parameters were analyzed. The survival rate (free of reoperation) was calculated at 2- and 5-years using the Kaplan-Meier survivorship analysis.

RESULTS

Thirty-nine patients were included with a mean age of 73.5 years and a mean follow-up of 5 years. Arthroplasty survivorship at 2 years was 73.7% and at 5 years was 67.5% (mean 8.4 years; range 6.7-10.2). Survivorship was inferior in the patients with episodes of instability (mean 2.5 years; range 0-5.42) (p<0.001). At least one episode of instability occurred in 26.3% of patients and 60% of these patients had a femoral head size 32mm or lower. At least one episode of instability occurred in 71.4% of patients with a greater trochanter fracture (p=0.008). The consolidation rate was 90.6% and the mortality rate was 23.7%. In the group of patients that died, 55.6% were submitted to at least one revision surgery (p=0.044).

CONCLUSION

Survivorship of an uncemented modular stem (MRP-Titan) in revision for PHF is significantly reduced by episodes of instability.

Staged Revision Hip Arthroplasty With Femoral Impaction Bone Grafting for Prosthetic Joint Infections: Radiostereometric Analyses and Clinical Outcomes at Minimum 5-Year Follow-Up

BACKGROUND

There are ongoing concerns regarding the use of bone graft following prosthetic joint infection and subsequent implant subsidence. The aim of this study was to determine whether the use of a cemented stem combined with femoral impaction bone grafting (FIBG) at second stage revision for infection results in stable femoral stem fixation, determined by accurate methods, and good clinical results.

METHODS

A prospective cohort of 29 patients underwent staged revision total hip arthroplasty for infection using an interval prosthesis followed by FIBG at the final reconstruction. The mean follow-up was 89 months (range, 8 to 167 months). Femoral implant subsidence was measured with radiostereometric analysis. Clinical outcomes included the Harris Hip Score, Harris Pain score and Société Internationale de Chirurgie Orthopédique et de Traumatologie activity scores.

RESULTS

At 2-years follow-up the median stem subsidence relative to femur was -1.36 mm (range, -0.31 to -4.98), while the cement subsidence relative to femur was -0.05 mm (range, 0.36 to -0.73). At 5-years follow-up, the median stem subsidence relative to femur was -1.89 mm (range, -0.27 to -6.35), while the cement subsidence relative to femur was -0.06 mm (range, 0.44 to -0.55). There were 25 patients who were confirmed infection-free after the second stage revision with FIBG. The median Harris Hip Score improved from 51 pre-operatively to 79 at 5 years (P = .0130), and Harris Pain score from 20 to 40 (P = .0038).

CONCLUSIONS

Stable femoral component fixation can be achieved with FIBG when reconstructing the femur after revision for infection without compromising infection cure rates and patient-reported outcomes.

The use of a standard-length conical tapered stem in hip revision arthroplasty to address Paprosky type I-II femoral defects: a prospective study of 87 patients

INTRODUCTION

Low-grade femoral defects in revision total hip arthroplasty (rTHA) might be preferably treated with a primary implant. Almost no previous study reported the use of standard-length conical tapered (SLCT) stems in these cases. We analyzed a series of cases using a SLCT stem in rTHA with Paprosky type I-II femoral defects. The purpose of the study was to determine clinical and radiographic outcomes in this series of rTHA.

MATERIALS AND METHODS

We prospectively followed 87 patients undergoing a femoral component rTHA: 53 Paprosky type I and 34 type II femoral defects. Patient-reported measures (Oxford Hip Score, EQ-5D, VAS pain during rest and activity) were administered at baseline, 1 and 2 years post-operatively. Radiographic subsidence overtime was scored. Kaplan-Meier curves were used to evaluate the subsidence over time, the complication-free survival, and the implant survivorship with reoperation and stem revision as endpoints.

RESULTS

The mean follow-up was 72.5 (SD ± 23.9) months. All PROMs significatively improved over time. The average subsidence was 2.8 (SD ± 3.2), 3.6 (SD ± 4.4), and 4.0 (SD ± 4.9) mm at 4, 12, and 24 months respectively. 6 stems had subsidence > 10 mm. The survival without complication was 0.85 (95% CI 0.94-0.77), while the implant survival without reoperation was 0.83 (95% CI 0.95-0.72). The overall stem survival rate was 93.7% (95% CI 0.91-0.97) at 2 years.

CONCLUSION

The use of a SLCT stem in rTHA with Paprosky type I-II femoral defects demonstrated good survival with low subsidence rates during the first 2 years after surgery. Surgeons should consider the use of this primary prosthesis as a potential treatment during stem revision in cases with limited femoral bone loss.

Outcome of the Wagner Cone femoral component for difficult anatomical conditions during total hip arthroplasty

PURPOSE

Total hip arthroplasty (THA) in patients with small or unusual proximal femoral anatomy is challenging due to sizing issues, control of version, and implant fixation. The Wagner Cone is a monoblock, fluted, tapered stem with successful outcomes for these patients; however, there is limited information on subsidence, a common finding with cementless stems.

METHODS

We retrospectively reviewed our cases using the modified Wagner Cone (Zimmer, Warsaw, IN) implanted over a 13-year period (2006-2019) in patients with small or abnormal proximal femoral anatomy. We performed 144 primary THAs in 114 patients using this prosthesis. Mean follow-up was 4.5 ± 3.4 years (range, 1-13 years). Common reasons for implantation were hip dysplasia (52%) and osteoarthritis in patients with small femoral proportions (22%). Analysis of outcomes included assessment of stem subsidence and stability.

RESULTS

Survival was 98.6% in aseptic cases; revision-free survival was 97.9%. Femoral subsidence occurred in 84 cases (58%). No subsidence progressed after 3 months. Of those that subsided, the mean distance was 2.8 ± 2.0 mm. There was less subsidence in stems that stabilized prior to six weeks (2.2 ± 1.4 mm) compared to those that continued until 12 weeks (3.9 ± 1.6, p = 0.02). Harris Hip, UCLA, and WOMAC scores significantly improved from pre-operative evaluation (p < 0.001*, p < 0.003*, p ≪ 0.001*); there was no difference in outcome between patients with and without subsidence (p = 0.430, p = 0.228, p = 0.147).

CONCLUSION

The modified Wagner Cone demonstrates excellent clinical outcomes in patients with challenging proximal femoral anatomy. Subsidence is minor, stops by 3 months, and does not compromise clinical outcome.

Comparison of two tapered fluted modular titanium (TFMT) stems used in revision hip arthroplasty from a single center

Background

TFMT stems are modular porous coated stems widely used in revision hip arthroplasty. Although TFMT stems are popular due to its proven advantage in the setting of severe bone deficiency, subsidence is a concern in these stem designs. We used two TFMT stems between 2013 and 2019, ARCOS(Zimmer Biomet) and Reclaim(Depuy Synthes). We reviewed our results and compared these stems.

Aim

The primary aim was a) look for early to mid-term stem survival b) radiological outcome measuring subsidence, secondary aim was to measure proximal femoral bone stock changes.

Materials and methods

Data was collected retrospectively. There were 51 patients in Arcos and 57 patients in Reclaim cohort. Both cohorts were comparable with respect to gender, side, BMI, paprosky defect, indications for surgery, ETO and stem length. The mean age group was 78.03 in Arcos and 73.75 in Reclaim.

Results

At a mean follow up of 5 years both cohorts showed excellent stem survival, 96.4% in Reclaim cohort as compared to 100% in Arcos. Subsidence was observed in both but none required a revision due to subsidence. There was a significant difference (p = 0.017) between the cohorts with mean of 2.3 mm(0-12 mm) in Arcos as compared to 4.5 mm(0-25 mm) in Reclaim. Both cohorts showed excellent restoration of proximal femoral bone stock.

Conclusion

Our data shows promising results using TFMT stems at 5 year follow up with more than 95% stem survival, minimal subsidence and good restoration of proximal femoral bone stock. The difference in subsidence between these stems may be attributed to stem geometry and difference in taper.

EBRA Migration Analysis of a Modular, Distally Fixed Stem in Hip Revision Arthroplasty: A Clinical and Radiological Study

Background: Massive osteolysis of the proximal femur makes stem revision a challenging procedure. EBRA-FCA provides the opportunity to determine stem migration, which is considered a predictive factor for implant survival. In this study, we aimed to analyze the migration behavior of a modular, distally fixed reconstruction prosthesis. Methods: Applying a retrospective study design, we reviewed all consecutive patients who received a cementless MP reconstruction prosthesis (Waldemar Link GmbH & Co. KG, Hamburg, Germany) at our Department between 2005 and 2019. We reviewed medical histories and performed radiological measurements using EBRA-FCA software. Results: A total of 67 stems in 62 patients (female 26; male 36) fulfilled our inclusion criteria. Mean age at surgery was 68.0 (range 38.7−88.44) years. EBRA migration analysis showed a median subsidence of 1.6 mm (range 0.0−20.6) at 24 months. The angle between stem and femur axis was 0.3° (range 0.0°−2.9°) at final follow-up. No correlation between body mass index and increased subsidence was found (p > 0.05). Overall revision-free rate amounted to 92.5% and revision-free rate for aseptic loosening to 98.5%. Furthermore, no case of material breakage was detected. Conclusions: In summary, the MP reconstruction prosthesis showed low subsidence and reduction in the migration rate over the investigated follow-up. Based on this, the modular stem can be considered as a good therapy option in challenging stem revisions offering various options to address the individual anatomical situation.

Diagnosis and Detection of Subtle Aseptic Loosening in Total Hip Arthroplasty

Aseptic loosening is a common cause of revision total hip arthroplasty (rTHA), and with the rising number of primary THAs, revisions for aseptic loosening represent a significant burden for arthroplasty surgeons. Aseptic loosening remains a diagnostic and management challenge. Loosening can occur as a result of inadequate initial fixation, mechanical loss of fixation over time, or a biological loss of fixation over time. However, in most cases, etiology is multifactorial, involving all 3 factors. The diagnosis of aseptic loosening involves a careful history, focused clinical exam, and thorough evaluation of imaging using several diagnostic modalities. The careful evaluation of serial radiographs remains the cornerstone of diagnosis with additional input from advanced imaging modalities such as FDG-PET, DEXA, MRI, and several others, each offering unique advantages and disadvantages. In certain patients, history and physical exam might be the only initial obvious signs of loosening, and thus, unexplained continuous pain augmented by imaging findings serves as an indication for revision surgery.

Aseptic Revision of Total Hip Arthroplasty With a Single Modular Femoral Stem and a Modified Extended Trochanteric Osteotomy-Treatment Assessment With the Forgotten Joint Score-12

Background

Aseptic loosening is among the most common reasons for revision total hip arthroplasty (RTHA). Modular revision stems implanted through an extended trochanteric osteotomy (ETO) promise good results, but patient-reported outcome measures (PROMs) are rarely conveyed. This study used the Forgotten Joint Score-12 (FJS-12) to assess patient-reported outcome in patients who had undergone RTHA for aseptic stem loosening using a modified ETO approach with a tapered, fluted modular stem.

Material and methods

A single-center analysis of aseptic RTHA was performed (2007–2019). Clinical results (range of motion, walking ability, function), radiographic results (ETO healing, stem subsidence), and PROMs (FJS-12, Harris Hip Score, European Quality of Life 5D Score) were assessed. Minimum follow-up duration was 1 year. Complications including revisions were recorded.

Results

Primary outcome parameters were assessed on 72 patients (mean age 73.3 years, mean body mass index 27.6kg/m²). Additional PROMs were collected by phone interviews from 41 patients (mean follow-up 5.7 years). In 76%, leg length was restored, and a normal gait was achieved. After 1 year, the ETO was healed in 93%; subsidence occurred in 8.3% of cases. The mean FJS-12 at the final follow-up was 85.6 ± 23.6, and the respective Harris Hip Score and European Quality of Life 5D Score averaged 87 ± 17.8 and 72.9 ± 15.9. Complication and revision rates were 33.3% and 13.9%, respectively.

Conclusion

Aseptic RTHA as presented here resulted in excellent PROMs in the medium term. FJS-12 score averaged 85.6 with a mean follow-up of 5.7 years. Treatment using a modular implant and a modified ETO was associated with good clinical and radiographic outcomes. Complication and revision rates were 33.3% and 13.9%, respectively.

Medium Term Radiographic and Clinical Outcomes Using a Modular Tapered Hip Revision Implant

Background

The rate of revision hip arthroplasty surgery is rising. Surgeons must use implants with proven outcomes to help overcome the technical challenges faced during revision surgery. However, outcome studies using these implants are limited. The aim of this study is to investigate the radiographic and clinical outcomes of the Stryker Restoration stem, the most commonly used hip revision stem in the United Kingdom (UK).

Methods

A retrospective review of a single surgeon case series was performed. Immediate postoperative radiographs were analyzed for offset and leg length discrepancy. Radiographic evidence of subsidence was assessed using follow-up radiographs. Kaplan-Meier survival analysis was applied using explantation and reoperation as endpoints. Patient-reported outcomes were measured using the Oxford Hip Score and EQ-5D-5L.

Results

One hundred ninety-eight cases were identified. Mean follow-up duration was 51.8 months (range: 24-121). Stem survival during this period was 98%. Reoperation for any reason was 13%. Mean subsidence was 4.18 mm. Analysis of variance testing showed no difference in mean subsidence between revision indications. Mean offset and leg length discrepancies were measured at 4.5 mm and 4.3 mm, respectively. The mean Oxford Hip Score for participants was 27.6.

Conclusions

This series demonstrates excellent implant survival, with radiographic parameters for reconstruction and subsidence levels comparable to those in the existing literature. The tapered modular hip revision stem provides surgeons with the intraoperative flexibility to overcome some of the anatomical difficulties encountered during revision surgery; this is reflected in the radiographic and clinical outcomes of the cohort in this study.

Modern Revision Femoral Stem Designs Have No Difference in Rates of Subsidence

BACKGROUND

Both modular and monoblock tapered fluted titanium (TFT) stems have gained popularity over fully porous-coated cylindrical (FPCC) femoral stem designs, but limited data exist comparing subsidence rates following revision total hip arthroplasty (THA). The purpose of this study is to determine differences in subsidence and clinical outcomes among 3 revision femoral stem designs.

METHODS

We reviewed a consecutive series of 335 patients who underwent femoral component revision to a cementless modular TFT (n = 225), monoblock TFT (n = 63), or FPCC (n = 47) stem between 2012 and 2019. We evaluated radiographic subsidence rates, re-revision rates, and patient-reported outcomes between the 3 stems. A multivariate regression analysis was performed to determine the independent effect of stem type on the risk of subsidence >5 mm.

RESULTS

At an average follow-up of 39 months (range, 12 to 96 months), there were no differences in mean subsidence rates (3.5 vs 2.4 vs 2.1 mm, P = .14), HOOS Jr scores (78 vs 74 vs 64 points, P = .15), or aseptic re-revision rates (4% vs 3% vs 0%, P = .29) between modular TFT, monoblock TFT, and FPCC stems. Although modular TFT stems were more often used in patients with extensive femoral bone loss (Paprosky III and IV), there were no differences in subsidence rates >5 mm among the 3 stems (P > .05) in multivariate analysis.

CONCLUSION

Modular TFT, monoblock TFT, and FPCC femoral stem designs all perform well in revision THA with no difference in clinical outcomes or subsidence rates. Surgeons should select the stem which they feel is the most clinically appropriate.

Outcomes of modular femoral revision implants and the effect of component design on subsidence

AIMS

Femoral revision component subsidence has been identified as predicting early failure in revision hip surgery. This comparative cohort study assessed the potential risk factors of subsidence in two commonly used femoral implant designs.

METHODS

A comparative cohort study was undertaken, analyzing a consecutive series of patients following revision total hip arthroplasties using either a tapered-modular (TM) fluted titanium or a porous-coated cylindrical modular (PCM) titanium femoral component, between April 2006 and May 2018. Clinical and radiological assessment was compared for both treatment cohorts. Risk factors for subsidence were assessed and compared.

RESULTS

In total, 65 TM and 35 PCM cases were included. At mean follow-up of seven years (1 to 13), subsidence was noted in both cohorts during the initial three months postoperatively (p < 0.001) then implants stabilized. Subsidence noted in 58.7% (38/65 cases) of the TM cohort (mean 2.3 mm, SD 3.5 mm) compared to 48.8% (17/35) of PCM cohort (mean 1.9 mm, SD 2.6 mm; p = 0.344). Subsidence of PCM cohort were significantly associated with extended trochanteric osteotomy (ETO) (p < 0.041). Although the ETO was used less frequently in PCM stem cohort (7/35), subsidence was noted in 85% (6/7) of them. Significant improvement of the final mean Oxford Hip Score (OHS) was reported in both treatment groups (p < 0.001).

CONCLUSION

Both modular TM and PCM revision femoral components subsided within the femur. TM implants subsided more frequently than PCM components if the femur was intact but with no difference in clinical outcomes. However, if an ETO is performed then a PCM component will subside significantly more and suggests the use of a TM implant may be advisable. Cite this article: Bone Joint J 2020;102-B(6):709-715.

Subsidence Following Revision Total Hip Arthroplasty Using Modular and Monolithic Components

BACKGROUND

The ideal femoral component in revision total hip arthroplasty (rTHA) remains undetermined; however, tapered, fluted, titanium (TFT) stems are now widely used with favorable results in all types of revision scenarios. With both modular and monoblock TFT stem options, neither has been proven to be superior. Femoral stem subsidence has been linked to aseptic loosening, instability, and leg length discrepancy. This study aims to assess stem subsidence of modular and monoblock TFT stems at a single urban orthopedic specialty hospital within a tertiary academic medical center.

METHODS

Electronic medical records of rTHAs performed between January 2013 and March 2018 utilizing modular and monoblock TFT stems were examined. Data collected included baseline demographics, surgical indication, femoral Paprosky classification, and stem subsidence at most recent follow up (3 months to 3 years). Two-sample t-tests and chi-squared tests were used for statistical analysis.

RESULTS

A total of 186 patients (106 modular, 80 monoblock) were included in the analysis. Modular stems underwent significantly greater subsidence than monoblock stems at latest radiographic follow-up (3.9 ± 2.6 vs 2.3 ± 2.5 mm, P < .001). A significantly greater proportion of modular stems underwent >5 mm of subsidence at latest follow-up (29.2% vs 11.3%, P < .001).

CONCLUSION

Monoblock TFT stems have displayed promising clinical results in prior studies, and now have been shown to decrease the incidence of postoperative subsidence. With the potential for stem subsidence to lead to aseptic loosening, limb length discrepancy, and instability, the orthopedic surgeon should weigh the risks and benefits of utilizing modular vs monoblock TFT stems in rTHA.

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

AIMS

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.

METHODS

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).

RESULTS

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).

CONCLUSION

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.

Survivorship of the Modular Femoral Revision Stem

The geriatric population represents a rapidly growing segment of society with prolonged life expectancies and more active lifestyles. Many of these patients have already undergone primary total hip arthroplasty (THA) and are presenting with aseptic loosening, polyethylene wear, osteolysis, or periprosthetic fractures. Therefore, the demand for hip revision procedures is expected to grow. Currently, there are many modular implant options available for use in complicated revision THA. Early results of modular femoral revision systems are promising for the treatment of the deficient femur in complex revision THA. The objective of this study was to evaluate component survivorship of a modular femoral revision system in revision THA. A retrospective review was conducted using electronic health records of patients who underwent revision THA performed by 1 of 3 surgeon investigators from 2010 through 2014. The authors included all patients who underwent a revision THA using a specific modular femoral revision system. The authors evaluated component survivorship and time to re-revision THA. Fifty-one revision THAs were included. Seven patients required a second revision THA (13.7%; 95% confidence interval, 4%-23%). Mean time to re-revision THA was 4.88±3.9 months. Kaplan-Meier survivorship using re-revision for any reason was 86.3% at 60 months. This study showed excellent component survivorship of the specific modular femoral revision system in revision THA. [Orthopedics. 2019; 42(5):294-298.].

Randomised clinical trial assessing migration of uncemented primary total hip replacement stems, with and without autologous impaction bone grafting

PURPOSE

Uncemented stems in primary total hip replacement (THR) are concerning in the elderly due to ectatic femoral canals and cortical thinning resulting in higher incidence of fracture and subsidence in this population. To obviate this concern, the authors developed a technique using autologous impaction bone grafting to achieve a better fitting femoral stem. The aim of this randomised clinical trial was to assess the efficacy of the technique.

METHODS

From 2013 to 2015, a total of 98 consecutive participants (100 primary THR procedures) were inducted into a single-institution, single-blinded, randomised clinical trial assessing, with radiostereometric analysis (RSA), the efficacy of autologous impaction bone grafting in uncemented primary THR compared with traditional uncemented primary THR technique. The primary outcome measure was femoral component migration using RSA. Secondary outcomes were post-operative proximal femoral bone density (using DEXA), hip function and quality of life using Oxford Hip Score (OHS) and Short Form-12 Health Survey (SF-12), hip pain and patient satisfaction.

RESULTS

There was no difference in femoral component stability (p > 0.5) or calcar resorption between the Graft and No Graft Groups at two years. There was also no difference in OHS, SF-12, pain or satisfaction between the Graft and No Graft Groups at two years (p > 0.39).

CONCLUSIONS

Autologous impaction bone grafting in uncemented primary THR has shown its short-term post-operative outcomes to be equivalent to standard uncemented technique, whilst offering a better fit in patients who are between femoral stem sizes.

AUSTRALIAN CLINICAL TRIAL REGISTRATION NUMBER

ACTRN12618000652279.

Early radiological and functional outcomes for a cementless press-fit design modular femoral stem revision system

AIM:

To assess early radiological and functional outcomes of revision hip surgery with a cementless press-fit design femoral stem.

PATIENTS AND METHODS:

A retrospective review of 48 consecutive revision total hip replacements using the RECLAIM revision hip system, between October 2012 and August 2015. Radiographic assessment was undertaken with serial anteroposterior (AP) X-rays of the pelvis. Risk factors for subsidence were evaluated. Prospective clinical follow up was performed on 21 patients to assess functional outcomes.

RESULTS:

Mean stem subsidence was 1.1 mm (95% confidence interval[CI]: 0.63-1.57). Median follow up of 12 months. An inverse relationship was observed between level of subsidence and femoral stem diameter r = -0.45, p = 0.001. Subsidence at the time of follow-up assessment was correlated with initial subsidence (correlation coefficient rho 0.69, p = 0.001). The mean Merle d'Aubigne score at the latest follow up was 14.2 (range 8-17). The mean OHS was 34.1 (range 15-48).

CONCLUSION:

Early radiological and functional outcomes for the RECLAIM revision system showed very low levels of subsidence and good functional outcomes. There was an association with smaller diameter femoral stems and greater levels of subsidence.

Cementless revision femoral stems application of press-fit principles and clinical outcomes

BACKGROUND

Cementless femoral stems are currently used in revision total hip arthroplasty (THA) with the surgeon choosing between various fixation modes. The outcomes are good in the medium term; however, some failures have been attributed to technical errors during implantation. When the decision has been made to use a press-fit implant, the impact of the surgeon's technique on the functional outcomes have not been explored in-depth. This led us to carry out a retrospective study on a large population of total hip arthroplasty patients which aims were achieved press-fit to (1) determine the impact of the type of primary fixation (with and without press-fit) on the functional outcomes; (2) specify the effect of stem length on the functional scores when diaphyseal press-fit is achieved and (3) analyse the main reasons why a true press-fit effect was not achieved (three-point fixation).

HYPOTHESIS

There is a relationship between the primary fixation method by press-fit of a revision femoral stem and the functional outcomes.

PATIENTS AND METHODS

We performed a retrospective analysis of a continuous cohort of 244 THA revision cases with a mean follow-up of 6.1 ± 3.5 years (range, 2-18). The femoral area in which close contact was achieved (shared interface between the bone and implant) was used to define various types of press-fit fixation. The functional outcomes were determined using the Harris Hip Score (HHS) and the Merle d'AubignéPostel score (MAP score) out of 12 points (pain and walking items).

RESULTS

The post-operative HHS averaged 90.83 ± 7.51 for proximal press-fit and 80.14 ± 14.93 with no press-fit (p = 0.01). The MAP averaged 10.83 ± 1.03 for proximal press-fit and 9.75 ± 2.09 with no press-fit (p = 0.09). The MAP score was worse for long diaphyseal press-fit than for short press-fit (p = 0.02). Use of a long stem with an endofemoral route or an overly small femoral window in patients with a curved femur is the main reason that three-point fixation occurred instead of press-fit.

CONCLUSIONS

While press-fit is an effective concept, it is a demanding one that requires the surgeon to choose the correct surgical strategy for the patient's anatomy. A meticulous surgical technique is required to achieve proximal press-fit or at a minimum, short diaphyseal press-fit.

Risk Factors for Subsidence of Modular Fluted Tapered Stems Used During Revision Total Hip Arthroplasty for Periprosthetic Hip Fractures

BACKGROUND

The objective of this study was to review Vancouver B₂ and B₃ periprosthetic hip fractures treated with uncemented modular fluted tapered stems to analyze survivorship, risk factors for stem subsidence, and clinical outcomes.

METHODS

We identified 61 Vancouver B₂ and B₃ periprosthetic hip fractures treated with modular fluted tapered implants. Survivorship, radiographic outcomes, and clinical outcomes were assessed. The mean age at the time of surgery was 72 years, mean body mass index was 30, and mean follow-up was 4.5 years (range, 2-10 years).

RESULTS

Survivorship free of reoperation or implant revision at 5 years was 89% and 93%, respectively. Eight (13%) stems subsided a mean distance of 18 ± 8 mm (range, 8-28 mm). Stem subsidence was not correlated with age, gender, Vancouver fracture classification, stem bypass, stem length, or stem diameter. Subsidence was correlated with Dorr C type femora (50% vs 7%, 95% confidence interval 9%-72%; P = .007) and strut grafting (50% vs 9%, 95% confidence interval 6%-70%; P = .01). All cases of subsidence stabilized without revision. Subsidence was not correlated with nonunion, reoperation, revision, or a clinical outcome.

CONCLUSIONS

Modular fluted tapered stems had excellent survivorship free of reoperation and implant revision when used for the treatment of Vancouver B₂ and B₃ periprosthetic femur fractures. Poor bone morphology and the use of strut grafts, both proxies for compromised bone stock and distal fracture patterns, were correlated with stem subsidence. All subsided stems stabilized, and noted subsidence did not portend a worse clinical outcome.

LEVEL OF EVIDENCE

Level III, retrospective cohort.

Nonmodular Tapered Fluted Titanium Stems Osseointegrate Reliably at Short Term in Revision THAs

BACKGROUND

The ideal femoral component for revision THA is undecided. Cylindrical nonmodular stems have been associated with stress shielding, whereas junctional fractures have been reported with tapered fluted modular titanium stems. We have used a tapered fluted nonmodular titanium femoral component (Wagner Self-locking [SL] femoral stem) to mitigate this risk. This component has been used extensively in Europe by its designer surgeons, but to our knowledge, it has not been studied in North America. Added to this, the design of the component has changed since early reports.

QUESTIONS/PURPOSES

We asked: (1) Does the Wagner SL stem have low rates of rerevision and other complications at a minimum 2 years after surgery? (2) Is the Wagner SL stem associated with high levels of patient function and pain relief at a minimum 2 years after surgery? (3) Does the Wagner SL stem have low rates of subsidence at a minimum 2 years after surgery? (4) Is the Wagner SL stem associated with proximal femoral bone remodeling at a minimum 2 years after surgery?

METHOD

Between May 2011 and December 2012, we performed 198 femoral revisions, of which 104 (53%) were performed using the Wagner SL femoral stem; during that period, our institution gradually shifted toward increasing use of these stems for all but the most severe revisions, in which modular fluted stems and proximal femoral replacements still are used on an occasional basis. Median followup in this retrospective study was 32 months (range, 24-46 months), and one patient was lost to followup before the 2-year minimum. The femoral deformities in this series were Paprosky Type I (10 hips), Paprosky Type II (26), Paprosky Type IIIA (52), Paprosky Type IIIB (nine), and Paprosky Type IV (two). Functional assessment was performed using the Oxford Hip Score (OHS), WOMAC, SF-12, and the University of California Los Angeles (UCLA) activity score. All complications and cases of revision were documented. All patients had radiographs performed within 1 year of the latest followup. These were assessed by two surgeons for signs of proximal femoral bone remodeling and subsidence.

RESULTS

Complete preoperative scores were available for 98 patients (98 of 104; 94%). The mean OHS preoperatively and at final followup were 39 (SD, 15) and 87 (SD, 19), respectively (p < 0.001; mean difference, 48; 95% CI, 43-53). Average WOMAC scores were 44 (SD, 15) and 87 (SD, 20), respectively (p < 0.001; mean difference, 43; 95% CI, 38-48). At final followup, signs of restoration of proximal femoral bone stock was noted in 45 of 103 hips (44%). Six (six of 104; 6%) patients had subsidence of 10 mm to 15 mm. In the remainder (98 of 104; 94%), the mean subsidence was 2 mm (range, 0-9 mm). One revision was performed for loosening associated with infection.

CONCLUSIONS

The Wagner SL stem is a viable option for patients with Paprosky Types II and III defects undergoing revision THA. This component provides high levels of patient function with low revision rates and low rates of subsidence during the early postoperative phase. They provide a viable alternative to modular components for treatment of Types II and III defects without the risk of junctional fractures. They can be used for very selected Type IV defects, however this extent of bone loss is most easily addressed with other techniques such as a proximal femoral replacement.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Femoral revision with a primary cementless stem

INTRODUCTION

The use of a primary cementless component is a tempting option for revision total hip arthrosplasty (reTHA), however, the results of this type of revision have not been clearly determined. The goal of this retrospective study was to determine: if revision with a primary anatomical cementless femoral stem gives adequate bone fixation; the rate of secondary subsidence or recurrent loosening; the survival rate with this device.

HYPOTHESIS

Revision with a primary anatomical cementless femoral stem results in a low rate of subsidence and recurrent loosening.

MATERIALS AND METHODS

This retrospective series of 43 reTHA performed between 1994 and 2012 included 43 patients, mean age 66 years old (37-90) with a minimum follow-up of 24months. There were grade 1 (n=24) or 2A (n=19) bone defects according to the Paprosky classification. The causes of revision were: aseptic loosening in 27, septic loosening in 6, malposition of the implant in 7 and periprosthetic fractures in 3. Clinical (Postel Merle d'Aubigné [PMA] and Harris scores), and radiological (subsidence) assessment was performed, as well as survival analysis (with a 95% confidence interval).

RESULTS

All components were changed through posterolateral approach without femorotomy. In four cases de-escalation (use of a primary component for secondary revision of a prior revision component) was performed. There were no perioperative fractures or perforations. After a mean 47months (24-134), the mean PMA score increased from 10 (5-15) to 16 (11-18), and the Harris score from 58 (20-80) to 85 (66-96). Radiological assessment did not show any extensive radiolucencies or secondary subsidence. Only 3 components were placed in a varus position, with no clinical consequences. One patient had subsequent revision for recurrent dislocations. Estimated survival at 80months by Kaplan-Meier analysis was 85% (CI 95%: 64-100%).

DISCUSSION

There are very few studies in the literature (7 series) on this topic, which shows the reluctance of surgeons to use this technique. Placement of a primary femoral stem requires good metaphyseal bone quality for primary stability. Thus, the indication is limited to Paprosky 1 and 2A stages. Revision surgery must be performed by endofemoral approach requiring good preoperative planning, as well as knowledge of the explanted component and a revision component must be available, if necessary, in the operating room.

LEVEL OF EVIDENCE

Retrospective study, level 4.

Can a Conical Implant Successfully Address Complex Anatomy in Primary THA? Radiographs and Hip Scores at Early Followup

BACKGROUND

Total hip arthroplasty (THA) in patients with small or abnormal proximal femoral anatomy is challenging as a result of complex anatomic deformities in the hip. It is unclear which stem is the most appropriate for these patients. One possible implant design that may help meet this need is the modified Wagner Cone prosthesis, whose design consists of monoblock cone with splines; however, to our knowledge, no clinical results have been published using this implant.

QUESTIONS/PURPOSES

We evaluated the hip scores and radiographic results (including signs of osseointegration and subsidence) of complex primary THA using the modified Wagner Cone cementless femoral component in patients with small or abnormal proximal femoral anatomic proportions.

METHODS

Between 2006 and 2011, we performed 59 THAs on patients whose femoral geometry precluded the use of standard-sized implants. Of these, 49 (83%) received the modified Wagner Cone prosthesis. During this time, our indications for use of the Wagner Cone implant in such patients included: femoral neck retroversion, excessive anteversion of the femoral neck, or small proximal femora not suitable for standard implants. Of those, 40 patients with 49 THAs were available for radiographic and clinical followup at a minimum of 3 years, and no patients were lost to followup. The diagnosis included developmental dysplasia of hip (22 patients, 28 hips), secondary trauma or posttuberculosis osteoarthritis (nine patients, 10 hips), and hip disease secondary to other disorders (eight patients, nine hips) and osteonecrosis (one patients, two hips). Two versions of the stem with 135° (28 hips) or 125° (21 hips) neck angle versions were used to reestablish normal hip biomechanics. Version angle was chosen based on preoperative templating. Cementless cups with screws were used for the acetabulum. Mean followup was 4 years (range, 3-7 years). Study endpoints were the Harris hip score and radiographic evaluations by a surgeon not involved in the clinical care of the patients (QZ); radiographic analysis included evaluating for the presence or absence of signs of osseointegration (including Engh's criteria) and subsidence.

RESULTS

The Harris hip score improved from a mean of 41 ± 9 preoperatively to a mean of 85 ± 10 at last followup (p < 0.01). The mean vertical subsidence was 1.5 ± 1.1 mm. Radiographic evaluation demonstrated stability (no further subsidence) of all implants at last followup. Endosteal spot welds were found in 32 hips (65%). No progressive radiolucencies were observed. One patient (one hip) underwent revision surgery as a result of late infection; no other revisions were performed.

CONCLUSIONS

The modified Wagner Cone femoral stem has provided improvements in hip scores and promising short-term radiographic results at short-term followup in complex cementless THA associated with abnormal or small femoral anatomical proportions in which standard implants are inappropriate. Longer followup will be needed to see if these results endure. Randomized trials are needed to determine the optimal stem design for these patients.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Bipolar Hemarthroplasty Using Cementless Conical Stem for Treatment of Dorr Type B and C Femoral Neck Fracture

PURPOSE

The current study aims to evaluate the clinical and the radiological outcome of bipolar hemiarthroplasty using cementless cone stem to treat osteoporotic femoral neck fracture and compare the results according to the proximal femur geometry.

MATERIALS AND METHODS

Seventy-five hips (75 patients) that underwent bipolar hemiarthroplasty with cementless cone stem between September 2006 and December 2011 were analyzed. The minimum follow-up period was 3 years. Thirty-three hips were classified as type B and 41 as type C. The clinical outcome was assessed using Harris hip score and the walking ability score. Radiographic evaluation was performed to evaluate the stability of the prosthesis.

RESULTS

At the most recent follow up, the mean Harris hip score was 86 (range, 70-92) and 65% recovered to preoperative ambulatory status. In the radiographic exam, stable stem fixation was achieved in all cases. For the complications, eight hips developed deep vein thrombosis while three hips showed heterotopic ossification. Dislocation and delayed deep infection occurred in one hip resepectively. There were no significance differences in Harris hip score and walking ability score when the type B group was compare with the type C.

CONCLUSION

Bipolar hemiarthroplasty with cementless cone stem showed an excellent early outcome both clinically and radiographically regardless of the shape of the proximal femur. We believe this prosthesis can provide early stability to the Dorr type B and C femur and is an effective treatment for treating osteoporotic femoral neck fracture.

Assessment of fixation in cementless femoral revision of total hip arthroplasty: comparison of the Engh score versus radiolucent line measurement

PURPOSE

To assess osseointegration and stability of a primary cementless femoral stem, many scoring systems have been developed, but none of them have taken into account only the radiolucent line. The purposes of this study were (1) to compare the results between the Engh score to assess osseointegration and stability of the cementless stem with results of a score called the O-SS score (osseointegration-secondary stability), which takes into account the radiolucent line, (2) to verify the relationship between these two scores and the functional results, and (3) to verify if there is a relationship between the O-SS score and secondary subsidence or a pedestal.

METHODS

A clinical and radiological evaluation was performed in a group of 100 hip prosthesis revisions comparing the results obtained by Engh score and O-SS score for which reproducibility was analysed.

RESULTS

Inter-observer reproducibility was estimated to be average at 0.5 and intra-observer reproducibility good at 0.7. The correlation with the Engh score was good at r = 0.59 (p < 0.0001). For the 80 cases assessed O-SS score as very good/good, Harris hip score was at 83.7 versus 78.25 for the 20 cases assessed as average/poor (p = 0.07). For the 73 cases with assessed Engh score as very good/good, this score was at 82.8 versus 82.14 for the 27 cases assessed as average/poor. No correlation between the O-SS score and secondary subsidence (p = 0.2) or pedestal (p = 0.2) was noticed.

CONCLUSION

The evaluation of the clear radiolucent line alone, extent and location, is a sufficient condition to assess osseointegration and secondary stability of a cementless femoral stem.

Mid-term results of previously cemented hip arthroplasties revised with uncemented modular femoral components: a retrospective study

BACKGROUND

We evaluated the mid-term results of previously cemented hip arthroplasties revised with uncemented modular femoral components.

METHODS

The study included 40 patients (36 females (90 %) and 4 males (10 %), mean age 67.6 years, range 39-87 years) who underwent revision of a previously cemented hip prosthesis with an uncemented modular femoral stem between 2005 and 2009. The indications for revision were femoral aseptic loosening in 38 (95 %) cases and acetabular protrusion in 2 (5 %). According to the Paprosky classification, the femoral defect was type 1 in 10 (25 %) patients, type 2 in 16 (40 %), type 3a in 11 (27.5 %), type 3b in 2 (5 %) and type 4 in 1 (2.5 %). The Harris hip score was used for the clinical evaluation. Femoral vertical subsidence, the cortical index and femoral stem stability were assessed radiologically. The mean follow-up period was 84 months (range 61-95 months).

RESULTS

The mean Harris hip score was 41.4 (range 35.4-44.4) preoperatively and 80.9 (range 65.6-98.3) at the final follow-up examination (p < 0.05). Mean vertical subsidence was 5.7 mm (range 2.5-10.5 mm) in seven (17.5 %) patients. Stable bone fixation was observed in 38 (95 %) patients, fibrous stable fixation in 2 (5 %) and no instability in any patient. Radiographs taken during the early postoperative period revealed that the cortical index was a mean of 1.34 (range 1.11-1.73) and a mean of 1.55 on the final follow-up radiographic examinations (range 1.16-1.91) (p < 0.01).

CONCLUSIONS

Satisfactory results were achieved using uncemented modular femoral components during revision of previously cemented femoral components. Many modular femoral stems provide primary stability by filling femoral bone losses and help determine stem length, offset and anteversion.

Risk Factors for Subsidence of a Modular Tapered Femoral Stem Used for Revision Total Hip Arthroplasty

The purpose of this study was to determine the incidence, and the clinical and radiographic risk factors for significant subsidence of a cementless, modular tapered revision femoral stem. Femoral stem subsidence of at least 10 mm or subsidence requiring revision was considered significant subsidence. Ninety-seven patients (99 hips) were included with minimum radiographic follow-up of one year (mean 34 months; range, 12-91 months). The mean stem subsidence was 4.5 mm (range, 0-44 mm). Fourteen out of 99 (14.1%) stems had significant subsidence and 6 (6.1%) stems required revision due to subsidence. Patient weight greater than 80 kg (P=0.04) and femoral stem press-fit distance of less than 2 cm (P<0.01) were both independent risk factors for significant stem subsidence.

Osseointegration of Fitmore stem in total hip arthroplasty

Currently, an increasing number of younger patients undergo total hip arthroplasty surgery. This has led to a minimal invasive approach and the use of short, bone preserving, femoral stems. In this study, we sought to evaluate osseointegration of the Fitmore stem (Zimmer, Inc; Warsaw, IN) during the first 12 mo after surgery, which reflects the biological phenomenon of osseointegration with radiographic evaluation and bone densitometry (dual-energy X-ray absorptiometry). We evaluated 33 patients (mean age 62.3) using dual-energy X-ray absorptiometry scan around the stem and X-ray. Moreover, we studied functional recovery using the Harris Hip Score, timed up and go test, and a quality of life form (SF-36), during the follow-up period. At 12 mo, we observed an increased periprosthetic bone mineral density in region of interest 1 (1.7%) and region of interest 7 (8.3%), where there is usually a greater amount of bone resorption. Also Harris Hip Score, timed up and go test, and SF-36 showed an improvement of clinical conditions of all patients. We also used a control group with a standard stem implanted. Because this is the first study correlating osseointegration and clinical outcome of the Fitmore stem, further clinical studies will be necessary to confirm good/positive results and a long stable fixation.