Proximally versus fully porous-coated femoral stems: a multicenter randomized trial

What role for short stems in 2023?

Current trends in total hip replacement aim at soft tissue and bone stock conservation. At the same time, mean patient age has been decreasing from decade to decade, raising the issue of iterative revision. Short stems seek to resolve the problem on the femoral side. Hopefully, revision of a short stem will be easier and bone stock depletion will be less than with a standard stem. Short stems also seem to have other advantages: automatically personalized biomechanical reconstruction, easier minimally invasive strategies, very low rate of hip pain, more harmonious distribution of bone stress, etc. Despite these advantages, however, use of short stems since their introduction in the late 1980s has varied from country to country, and is not widespread in France. The present study addressed several questions concerning these implants. Firstly, what is a "short" stem? Then, what are the indications and contraindications? Shortened standard stems do not come under the concept of short stem and will not be dealt with here. Furthermore, the learning curve and specificities of short stems need to be acquired. Implantation technique differs greatly from standard stems, and short stem implantation requires particular rigor. Results also need to be assessed, and especially the rate of complications as compared to standard stems. And lastly, it needs to be determined whether the advantages are real or only theoretical: this will determine their usefulness and role in the armamentarium, in which short stems are a new paradigm. LEVEL OF EVIDENCE: Expert opinion.

Alignment and mechanics evaluation for a compaction broach stem versus a blade style proximal press fit stem using 3-Dimensional planning

Three-dimensional (3D) preoperative planning tools can be used to help plan and compare component alignment scenarios for different total hip arthroplasty systems to ultimately improve postoperative outcomes and patient satisfaction. The objective of this study is to use 3D preoperative planning tools based on patient-specific bone models to compare two different stem designs, specifically a compaction broach stem and a proximal press fit stem. The planner uses patient-specific proximal femoral bone morphology to suggest a specific implant size and placement. The planner then allows for preoperative predictions of component head positioning, stem fit within the canal, and potential cortical bone reaming that must be done, as well as postoperative predictions of stability and mechanics. The stems were evaluated to determine the accuracy of stem placement, the theoretical volumetric bone removal/reaming required to achieve a desired fit, and the associated postoperative mechanics. This study demonstrated that there was a difference in component alignment and predicted postoperative mechanics between a compaction broach stem and a press fit stem, with the compaction broach stem allowing for more accurate alignment with less required bone removal, resulting in improved postoperative stability and mechanics. This study also demonstrated that much of the stem misalignment for both systems occurred in the anterior/posterior direction. Overall, 3D preoperative planning offers significant benefits and novel intraoperative insight, and the industry should continue to enhance their THA preoperative planning tools.

Femoral stem taper geometry and porous coating in cementless direct anterior primary total hip arthroplasty

Objective

This study aims to compare the clinical outcomes and complications between a fully coated, dual-tapered hip stem versus a proximally coated, triple-tapered hip stem in patients undergoing cementless direct anterior (DA) primary total hip arthroplasty (THA).

Methods

A retrospective analysis was conducted on patients who underwent primary THA with either a fully coated, dual-tapered hip stem or a proximally coated, triple-tapered stem with at least a 1-year follow up. Exclusion criteria included any patients that did not receive either femoral stem, those undergoing bilateral THA, those with a surgical approach other than DA, those with an indication other than osteoarthritis, avascular necrosis (AVN), or femoral neck fracture, and those that had a cemented femoral component. Complications and clinical outcomes were assessed. Statistical analyses were conducted to identify significant differences between the groups.

Results

A total of 95 patients were included in the study. The average ages for the dual-tapered and triple-tapered stem cohorts were 63.6 and 59.5, respectively (p = 0.168). At 1-year follow-up, no significant differences were seen between the groups in terms of ambulatory status, ROM, and patient satisfaction (p = 0.414, p = 0.106, and p = 0.126). 6 (18 %) of the patients receiving the dual-tapered, fully coated hip stem had at least one complication while 8 (13 %) of the triple-tapered, proximally coated hip stem patients did (p = 0.550).

Conclusion

Both hip stem cohorts demonstrated comparable clinical outcomes and complication rates in patients undergoing primary DA THA and we believe that either hip stem may be a reasonable choice for patients. Future studies with larger sample sizes and longer follow-up periods are warranted to validate these findings.

Satisfactory clinical and radiographic outcomes following revision total hip arthroplasty by direct anterior approach using primary femoral stems at 2-8 years of follow-up

INTRODUCTION

To report clinical and radiographic outcomes of revision total hip arthroplasty (THA) through the direct anterior approach (DAA) using primary stems.

MATERIALS AND METHODS

The authors assessed a consecutive series of revision THAs operated by DAA using primary (cemented and uncemented) stems between 1/1/2010 and 30/06/2017. The initial cohort comprised 47 patients (50 hips), aged 65 ± 10 years with BMI of 25 ± 4 kg/m2. Clinical assessment included modified Harris Hip Score (mHHS) and satisfaction with surgery. Radiographic assessment included radiolucent lines > 2 mm, bone remodelling, cortical hypertrophy, pedestal formation, and osteolysis. Linear regression analyses were performed.

RESULTS

Of the 50 hips (47 patients) in the initial cohort, intraoperative complications that did not require re-revision occurred in 5 hips. At a follow-up of > 2 years: 5 hips (10%) were lost to follow-up and 3 hips (6%) required stem re-revision, leaving a final cohort of 42 hips (40 patients). Postoperative complications that did not require re-revision occurred in 4 hips (8%). At 4.3 ± 1.6 years, post-revision mHHS was 89 ± 14 (range 47-100) and 38 patients were satisfied or very satisfied with revision surgery. Bone remodelling was observed in 8 hips (16%), cortical hypertrophy in 6 hips (12%), grade I heterotopic ossification in 7 hips (14%), and grade II in 1 hip (2%). There were no cases of radiolucent lines, pedestal formation, or osteolysis. Regression analyses revealed that post-revision mHHS was not associated with any variable.

CONCLUSIONS

Revision THA performed through the DAA using primary stems grants satisfactory clinical and radiographic outcomes at a minimum follow-up of two years.

A Study of Tibial Cyst Formation in Modular Stemmed Total Ankle Arthroplasty: Exploring a Possible Relationship to Smooth and Porous Coating on the Stem Segments

Vertical fixation through stemmed components has been a successful strategy in total ankle arthroplasty. Research in hip replacement surgery has demonstrated increased rates of stress shielding, aseptic loosening, thigh pain, and cystic formation around stemmed femoral implants extensively coated with porous surfaces. While some ankle prostheses have integrated porous coating technology with stemmed tibial implants, there is little to no research investigating the potential negative effects of bone bonding to the tibial stems and possible impact on tibial cyst formation. We performed a retrospective cohort study comparing the incidence of periprosthetic tibial cyst formation in smooth versus fully porous-coated stemmed tibial implants after undergoing total ankle implant arthroplasty. Radiographs were compared for postoperative rates of tibial cyst formation and bone bonding to the tibial stems. Relative risk for reoperation between the smooth and porous-coated implants was investigated. The smooth-stem group showed no incidence of tibial cyst formation nor signs of significant bone bonding to the tibial stems; however, the follow-up matched porous-coated group showed a rate of 63% of cystic formation with associated evidence of bone bonding on final radiographic follow-up (p < .01). Relative risk for reoperation was 0.74. Despite a higher incidence of tibial cyst formation in the stemmed ankle arthroplasty groups with porous coating, reoperation rates were similar. We theorize that the proximal bonding to the porous stem surface could impact the distal stems and result in the observed increase in cyst formation.

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

Background

Whether hip revision with a metaphyseal-fixation femoral stem component can restore the bone mass of the proximal femur remains unclear. The aims of this study were to identify whether the bone mineral density (BMD) of the proximal femur increases following hip revision with a metaphyseal-fixation femoral stem and to identify the factors associated with BMD recovery.

Methods

This was a retrospective study involving 36 patients who underwent hip arthroplasty with a metaphyseal-diaphyseal fixation stem (standard length stem) and had indications for hip revision, which was performed with a proximal press-fit short-stem prosthesis for each patient. Dual-energy X-ray absorptiometry (DEXA) was used to obtain, evaluate, and compare the BMD at baseline and one year and two years postoperatively. The proximal femur was divided into several independent areas according to the Gruen zone (Gruen 1 to Gruen 7 from the greater trochanter counterclockwise to the lesser trochanter). Logistic regression analyses were used to assess potential factors significantly associated with an increase in BMD.

Results

An increased BMD was obviously identified in the proximal femur. Two years after the surgery, the BMD of the Gruen 1, Gruen 2, Gruen 6, and Gruen 7 areas had increased by 22.6%, 12.6%, 16.2% and 24.2%, respectively, relative to baseline. Three independent risk factors associated with bone mineral density recovery were identified: age (OR=1.100, 95% CI=1.005-1.203, P=0.038), osteoporosis (OR=14.921, 95% CI=1.223-182.101, P=0.034) and fair to poor hip function (OR=13.142, 95% CI=1.024-168.582, P=0.048).

Conclusion

This study confirms that metaphyseal-fixation stem hip revision can indeed help restore bone mass in the proximal femur, especially in the Gruen 1, Gruen 2, Gruen 6 and Gruen 7 zones. It was also found that advanced age, osteoporosis, and fair to poor hip joint function were three important risk factors affecting the recovery of proximal femur bone mass after surgery.

Trial Registration

Retrospectively registered.

Dual-Energy X-Ray Absorptiometry (DEXA) Evaluation of the Bone Remodeling Effects of a Low-Modulus Composite Hip Stem After 2 Decades of Follow-Up

Background: The Epoch FullCoat Hip Stem (Zimmer) was an isoelastic composite femoral stem developed to address stem stiffness concerns. Purpose: We sought to evaluate the long-term bone mineral density (BMD) of a cohort of patients who underwent total hip arthroplasty (THA) using the Epoch isoelastic stem and having more than 2-decade follow-up. Methods: We conducted a retrospective chart review of all patients who were study subjects at our institution in a multicenter prospective trial for the Food and Drug Administration of the Epoch implant in the mid-1990s. Through this, we identified 16 patients who had dual-energy X-ray absorptiometry (DEXA) scans, with which we could determine BMD preoperatively and at 3 points postoperatively. Of these, 5 agreed to participate in the study (the others were deceased, unable or declined to participate, or were lost to follow-up) with mean follow-up of 22 years. These participants underwent clinical and radiographic evaluation consisting of a Harris hip score, anteroposterior (AP) pelvis and AP and lateral hip X-rays, and DEXA evaluation of both hips. BMD in the 7 Gruen zones at last follow-up was compared with immediate postoperative and 2-year follow-up. Results: At last follow-up, all stems were well-fixed with signs of extensive osteointegration. In proximal Gruen zones 1 and 7, patients underwent a decrease in BMD with more modest losses in Gruen zone 1. All patients demonstrated an increase in BMD in zones 2 through 6 at latest follow-up, except for 1 patient in Gruen zone 6. BMD changes were not limited to the first 2 years of follow-up. Conclusion: This small follow-up cohort study found excellent long-term clinical results, no plain radiographic signs of notable stress shielding, and general maintenance of BMD at a follow-up of over 20 years for this isoelastic stem. Long-term bone remodeling after implantation of the isoelastic stem resulted in increased BMD in Gruen zones 2 through 6, suggesting that composite implant designs may still have a role in THA.

When the Total Hip Replacement Fails: A Review on the Stress-Shielding Effect

Total hip arthroplasty is one of the most common and successful orthopedic surgeries. Sometimes, periprosthetic osteolysis occurs associated with the stress-shielding effect: it results in the reduction of bone density, where the femur is not correctly loaded, and in the formation of denser bone, where stresses are confined. This paper illustrates the stress shielding effect as a cause of the failing replacement of the hip joint. An extensive literature survey has been accomplished to describe the phenomenon and identify solutions. The latter refer to the design criteria and the choice of innovative materials/treatments for prosthetic device production. Experimental studies and numerical simulations have been reviewed. The paper includes an introduction to explain the scope; a section illustrating the causes of the stress shielding effect; a section focusing on recent attempts to redefine prosthetic device design criteria, current strategies to improve the osteointegration process, and a number of innovative biomaterials; functionally graded materials are presented in a dedicated section: they allow customizing prosthesis features with respect to the host bone. Conclusions recommend an integrated approach for the production of new prosthetic devices: the “engineering community” has to support the “medical community” to assure an effective translation of research results into clinical practice.

Comparison of periprosthetic bone mineral density between two types of short-stems in total hip arthroplasty with a mean follow-up of 4 years

INTRODUCTION

The use of short stems in primary hip arthroplasty has grown considerably in recent years, with a large variety of designs and stabilization methods available. Few studies have directly compared how these designs and fixation modes influence the bone mineral density (BMD) that is said to be better preserved with shorter implants. This led us to carry out a medium-term retrospective comparative study to (1) specify how the design of two different types of short stems influences the periprosthetic BMD, (2) compare the radiological and clinical outcomes of these stems.

HYPOTHESIS

The periprosthetic BMD of a short stem varies based on the implant's design.

MATERIALS AND METHODS

Ninety-three patients underwent total hip arthroplasty (THA) with a short stem between July 2012 and July 2014. Two groups of patients were formed: Vitae™ short stem (Adler Ortho, Milan, France), Optimys™ short stem (Mathys, Bettlach, Switzerland). The Vitae group consisted of 46 patients, while the Optimys group consisted of 47 patients. The mean age was 66 years, and the mean body mass index (BMI) was 26 kg/m². The groups had comparable age, BMI, sex, Harris Hip score and preoperative radiological features. Periprosthetic BMD of the two types of implants was determined between the 1^st and 4th year postoperative using dual-energy x-ray absorptiometry (DEXA) in the Gruen zones. The radiological and clinical outcomes were also determined.

RESULTS

There was a significant decrease in BMD in zone 7(-5.8%±0.1 CI_95%[-0.09; -0.02] (p=0.003)), zone 2 (-4.8% ±0.1 CI_95%[-0.093; -0.003] (p=0.038)) and zone 6 (-11% ±0.2 CI_95%[-0.19; -0.03] (p=0.009)) in the patients with Vitae stems and in zone 2 (-13.7%±0.3 CI_95%[-0.25; -0.03] (p=0.018)) in the patients with Optimys stems. A significant difference in BMD in zone 7 at 1 year (p=0.014) and 4 years (p=0.001) postoperative and in zone 6 (p=0.011) at 4 years postoperative existed between groups, with the Optimys group having higher BMD. There was a significant increase in femoral offset in the Optimys group but not the Vitae group: Δoffset=-0.50 mm±5.2 CI_95%[-2.05; 1.05] (p=0.522) and Δoffset=2.79 mm±4.2 CI_95%[1.21; 4.37] (p=0.001). The Harris Hip score was not significantly different between the two groups at 4 years postoperative (95.3±2.5 [88; 99] vs. 95.2±2.6 [88; 99] (p=0.991)).

DISCUSSION

The design of short stems appears to influence the distribution of loads and the periprosthetic BMD. These stems are associated with very good radiological and clinical results in the medium term. Bone remodeling appears to continue beyond 1 year after the THA procedure.

LEVEL OF EVIDENCE

III; Retrospective case-control study.

Effects of porous tantalum on periprosthetic bone remodeling around metaphyseal filling femoral stem: a multicenter, prospective, randomized controlled study

Periprosthetic bone loss due to adaptive bone remodeling is an important unresolved issue in cementless total hip arthroplasty (THA). The use of porous tantalum on the proximal surface of the femoral stem is expected to decrease postoperative bone loss around the prosthesis through early fixation. We conducted a multicenter randomized controlled study to determine if porous tantalum could reduce periprosthetic bone loss after THA. From October 2012 to September 2014, 118 patients (mean age, 61.5 years; 107 females and 11 males) were prospectively enrolled and were randomly allocated at a ratio of 1:1 to either a metaphyseal filling stem with a proximal porous tantalum coating (Trabecular Metal) or a conventional metaphyseal filling stem with fiber mesh coating (VerSys). Patients underwent dual-energy x-ray absorptiometry scans within 1 week after surgery (baseline) and at 6, 12, and 24 months after surgery to assess periprosthetic bone mineral density (BMD) in the 7 Gruen zones. In addition, the Japanese Orthopaedic Association hip score was assessed before surgery and at 6, 12, and 24 months after surgery. In the proximal periprosthetic region (zones 1 and 7), the Trabecular Metal group had significantly smaller reductions in BMD than the VerSys group throughout the study period. In the VerSys group, significant reductions in BMD compared to baseline were seen at each measurement point in all regions, except in zone 6 at 24 months. In the Trabecular Metal group, no significant reductions in BMD relative to baseline were seen in zones 1, 5, or 6 throughout the study period. Both groups demonstrated similar improvement in Japanese Orthopaedic Association hip scores over the study period. This study demonstrated that a proximally coated stem with porous tantalum has superior results over a conventional stem with titanium fiber mesh in terms of periprosthetic bone remodeling.

Distal femoral cortical hypertrophy not associated with thigh pain using a short stem femoral implant

BACKGROUND

Thigh pain following a well-fixed total hip arthroplasty (THA) remains problematic and a source of patient dissatisfaction. The purpose of this study is to evaluate if the development of distal femoral cortical hypertrophy (DFCH) is associated with postoperative thigh pain after THA.

METHODS

All patients who underwent an uncomplicated primary THA via a direct anterior approach with the Taperloc Microplasty (Zimmer Biomet, Warsaw, IN, USA) implant between 2011 and 2015 were mailed a pain drawing questionnaire. Radiographs were reviewed at 1 year minimum to determine cortical thickness change from immediate post-op. Thigh pain was compared to DFCH. 293 patients were included in the study.

RESULTS

Mean follow-up was 3.2 years. A total of 218 hips (74%) had cortical hypertrophy in Gruen zone 3 and 165 hips (56%) had cortical hypertrophy in Gruen zone 5. 52 hips (18%) had ⩾25% cortical hypertrophy in zone 3 and 91 hips (31%) had ⩾25% cortical hypertrophy in zone 5. A total of 44 patients (15%) reported anterior thigh pain and 43 patients (15%) reported lateral thigh pain. Development of DFCH in either Gruen zone 3 or 5 was not associated with anterior or lateral thigh pain. Stem size was positively correlated with zone 3 hypertrophy and inversely related to zone 5 hypertrophy. Thigh pain was not associated with patient age, gender, activity level or stem size.

CONCLUSIONS

The development of distal femoral cortical hypertrophy after THA with a short stem implant was high, but not associated with patient-reported anterior or lateral thigh pain.

A Large-Scale Fifteen-Year Minimum Survivorship of a Cementless Triple Tapered Femoral Stem

BACKGROUND

This study reports the long-term outcomes of a metaphyseal fit-and-fill cementless femoral component in total hip arthroplasty (THA) with a follow-up of 15-19 years.

METHODS

We conducted a retrospective review of 376 consecutive THAs (345 patients), using a triple tapered stem performed between 2000 and 2003 with a view to assessing survivorship and radiological and functional outcomes. Images were assessed for initial alignment, terminal osteolysis, or subsidence, while clinical outcomes were assessed using the St Michael's Hip Score.

RESULTS

Forty-five (11.9%) hips were lost to follow-up, 20 (5.31%) had died before our 15-year cutoff follow-up, and 4 (1.06%) had declined follow-up early on, leaving 307 hips (81.64%, 276 patients) available for both clinical and radiological follow-up at a minimum of 15 years (range 15-19). The mean age at the time of operation was 49.6 years (range 19-71) and the cohort included 131 (42.67%) male and 145 (47.23%) female patients. Seven stems (2.28%) were revised: 4 due to periprosthetic fractures, 2 for periprosthetic joint infection, and 1 for adverse reaction to metal debris at the trunnion. The St Michael's Hip Score improved from 14.2 (range 9-23) preoperatively to 22.3 (range 13 to 25) at the last documented follow-up (P = .000). Kaplan-Meier survivorship with stem revision for any reason as the end point was 97.70%. Worst-case scenario Kaplan-Meier survivorship, where all lost to follow-up are considered as failures, was 85.3%. No stem was revised for aseptic loosening.

CONCLUSION

This triple tapered stem in THA shows excellent survivorship beyond a minimum of 15 years.

Influence of femoral morphology and canal fill ratio on early radiological and clinical outcomes of uncemented total hip arthroplasty using a fully coated stem

Aims

The diversity of femoral morphology renders femoral component sizing in total hip arthroplasty (THA) challenging. We aimed to determine whether femoral morphology and femoral component filling influence early clinical and radiological outcomes following THA using fully hydroxyapatite (HA)-coated femoral components.

Methods

We retrospectively reviewed records of 183 primary uncemented THAs. Femoral morphology, including Dorr classification, canal bone ratio (CBR), canal flare index (CFI), and canal-calcar ratio (CCR), were calculated on preoperative radiographs. The canal fill ratio (CFR) was calculated at different levels relative to the lesser trochanter (LT) using immediate postoperative radiographs: P1, 2 cm above LT; P2, at LT; P3, 2 cm below LT; and D1, 7 cm below LT. At two years, radiological femoral component osseointegration was evaluated using the Engh score, and hip function using the Postel Merle d’Aubigné (PMA) and Oxford Hip Score (OHS).

Results

CFR was moderately correlated with CCR at P1 (r = 0.44; p < 0.001), P2 (r = 0.53; p < 0.001), and CFI at P1 (r = − 0.56; p < 0.001). Absence of spot welds (n = 3, 2%) was associated with lower CCR (p = 0.049), greater CFI (p = 0.017), and lower CFR at P3 (p = 0.015). Migration (n = 9, 7%) was associated with lower CFR at P2 (p = 0.028) and P3 (p = 0.007). Varus malalignment (n = 7, 5%), predominantly in Dorr A femurs (p = 0.028), was associated with lower CFR at all levels (p < 0.05). Absence of spot welds was associated with lower PMA gait (p = 0.012) and migration with worse OHS (p = 0.032).

Conclusion

This study revealed that femurs with insufficient proximal filling tend to have less favourable radiological outcomes following uncemented THA using a fully HA-coated double-tapered femoral component.

Cite this article: Bone Joint Res. 2020;9(4):182–191.

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.

Does Proximally Coated Single-Wedge Cementless Stem Work Well in Dorr Type C Femurs? Minimum 10-year Followup

BACKGROUND

Total hip arthroplasty (THA) with a proximally coated single-wedge (PSW) cementless stem had been generally considered not to be suitable for Dorr Type C femurs. This study compares the long term outcomes of PSW stem according to the type of proximal femoral geometry.

MATERIALS AND METHODS

307 primary THAs in 247 patients were performed with PSW cementless stem and followed up for over 10 years in this retrospective study. According to Dorr's criteria, 89 femurs were classified as Type A, 156 as Type B, and 62 as Type C. They were followed up for an average of 13.2 years (range 10.0-17.3 years). All the hips were evaluated clinically and radiologically.

RESULTS

There was no significant difference in stem survivorship and clinical outcomes including the incidence of thigh pain and the mean postoperative Harris hip score (HHS) in all three groups. No significant differences were observed in osteolysis, pedestal formation, or cortical hypertrophy among the groups. Radiolucent lines <2 mm in thickness in Gruen zone 4 and 7 (P = 0.003 and P = 0.044, respectively), spot-weld (P < 0.001), and stress shielding (P = 0.010) of proximal femur were more pronounced in Dorr C type femora than in Type A or B. Fifty-six intraoperative fractures were identified among 307 hips with PSW stems. The incidence of intraoperative or postoperative femoral fractures was not significantly different among the groups.

CONCLUSIONS

From over a 10-year followup, the PSW stem provided a recommendable option with satisfactory outcomes and excellent stem survivorship regardless of the Dorr type.

An evaluation of proximal femur bone density in young, active patients undergoing total hip arthroplasty at one year postoperatively

BACKGROUND:

Prior investigations have shown a decrease in periprosthetic bone mineral density (BMD) of the calcar following total hip arthroplasty (THA). The purpose of this investigation was to study proximal femur BMD in a cohort of young, active patients following THA at 1 year postoperatively using a recently introduced stem design.

METHODS:

This was a prospective, IRB-approved investigation of patients with an age <65 years, BMI <35 kg/m², and presymptomatic UCLA score of >6 undergoing a primary THA for a diagnosis of osteoarthritis. All patients received a titanium, proximally coated, tapered cementless femoral stem (ACCOLADE II, Stryker Inc, Mahwah, NJ, USA). Dual energy X-ray absorptiometry scans were performed at 6 weeks, 6 months, and 1 year postoperatively. Bone density was analyzed for 7 traditional Gruen zones with BMD ratios calculated for change in BMD compared with the baseline.

RESULTS:

31 patients (mean age of 52.6 + 6.5 years, BMI of 27.9 + 3.9 kg/m², and UCLA activity score of 7.3 + 1.9) were included. The mean BMD ratio decreased at the 6 months and 1 year interval in zones 1 and 2. However, the mean BMD ratio was maintained in Gruen zones 3 thru 7 with zone 7 (medial calcar) demonstrating 100% maintenance of the baseline BMD at 1 year.

CONCLUSION:

This study demonstrates the maintenance of medial calcar bone density at 1 year postoperatively in young, active patients undergoing THA. Further longitudinal analysis of this stem design is necessary to elucidate the significance of this finding.

Dual offset metaphyseal-filling stems in primary total hip arthroplasty in dysplastic hips after a minimum follow-up of ten years

PURPOSE

The aim of this study was to assess the long-term performance of tapered one-third proximally coated stems in dysplastic hips.

METHODS

This study included 135 dysplasia patients (150 hips) who underwent a total hip arthroplasty and had a minimum follow-up of ten years. Single design tapered stems were used in all patients. There were 112 women (83%) and 23 men (17%) with a mean age of 45 years (23 to 72) at the time of surgery. The mean follow-up was 14.7 years (10 to 16.8). For clinical evaluation, the Harris Hip Score and Merle D'Aubigne scale were used pre-operatively and at the final follow-up. Implant survival was calculated using Kaplan-Meier survivorship analysis, with failure defined as a component revision for any reason.

RESULTS

Overall, one stem was revised for a deep infection. There were no other femoral stem revisions secondary to loosening, wear, periprosthetic fracture, or instability. Radiographic evaluation showed excellent stem osteointegration in all cases. Kaplan-Meier survivorship, with stem revision for any reason as the end point, was 98% at 14 years (95% confidence interval 92.5 to 99.8).

CONCLUSION

This study demonstrates that a dual offset tapered stem achieved excellent survivorship and stability, as well as good clinical outcome scores with minimal thigh pain and stress shielding in patients with arthritis and developmental dysplasia of the hip; a dual offset tapered stem may be a suitable option for primary total hip arthroplasty in this group.

Long-term bone remodelling around 'legendary' cementless femoral stems

Bone remodelling around a stem is an unavoidable long-term physiological process highly related to implant design. For some predisposed patients, it can lead to periprosthetic bone loss secondary to severe stress-shielding, which is thought to be detrimental by contributing to late loosening, late periprosthetic fracture, and thus rendering revision surgery more complicated.However, these concerns remain theoretical, since late loosening has yet to be documented among bone ingrowth cementless stems demonstrating periprosthetic bone loss associated with stress-shielding.Because none of the stems replicate the physiological load pattern on the proximal femur, each stem design is associated with a specific load pattern leading to specific adaptive periprosthetic bone remodelling. In their daily practice, orthopaedic surgeons need to differentiate physiological long-term bone remodelling patterns from pathological conditions such as loosening, sepsis or osteolysis.To aid in that process, we decided to clarify the behaviour of the five most used femoral stems. In order to provide translational knowledge, we decided to gather the designers' and experts' knowledge and experience related to the design rationale and the long-term bone remodelling of the following femoral stems we deemed 'legendary' and still commonly used: Corail (Depuy); Taperloc (Biomet); AML (Depuy); Alloclassic (Zimmer); and CLS-Spotorno (Zimmer). Cite this article: EFORT Open Rev 2018;3:45-57. DOI: 10.1302/2058-5241.3.170024.

The Synergy cementless femoral stem in primary total hip arthroplasty at a minimum follow-up of 15 years

AIMS

We report on the outcome of the Synergy cementless femoral stem with a minimum follow-up of 15 years (15 to 17).

PATIENTS AND METHODS

A retrospective review was undertaken of a consecutive series of 112 routine primary cementless total hip arthroplasties (THAs) in 102 patients (112 hips). There were 60 female and 42 male patients with a mean age of 61 years (18 to 82) at the time of surgery. A total of 78 hips in the 69 patients remain in situ; nine hips in eight patients died before 15 years, and 16 hips in 16 patients were revised. Clinical outcome scores and radiographs were available for 94 hips in 85 patients.

RESULTS

In all, four stems were revised. One stem was revised for aseptic loosening; two stems because of deep infection; and one because of periprosthetic femoral fracture. There was a significant improvement in all components of the Western Ontario and McMaster Universities Osteoarthritis Index score at the final follow-up (total: p < 0.001, pain: p < 0.001, stiffness: p < 0.001, function: p < 0.001). The mean Harris Hip Scores improved from 47 points (27 to 59) pre-operatively to 89 points (65 to 100) at the latest follow-up (p < 0.001). Kaplan-Meier survivorship, with stem revision for aseptic loosening as the endpoint, was 98.9% at 15 years (95% confidence interval (CI) 96.9 to 100, number at risk at 15 years: 90) and with stem revision for any reason was 95.7% (95% CI 91.7 to 99.8, number at risk at 15 years: 90).

CONCLUSION

The Synergy cementless femoral stem demonstrates excellent survivorship and functional outcomes at 15 years. Cite this article: Bone Joint J 2017;99-B:29-36.

Is the Direct Superior, Iliotibial Band-Sparing Approach Associated With Decreased Pain After Total Hip Arthroplasty?

BACKGROUND

Recently, the direct superior approach (DSA) has been introduced in total hip arthroplasty (THA) with the goal of limiting soft tissue dissection. This study's purpose was to use a visual pain diagram questionnaire to determine the location and severity of pain in patients undergoing THA via a DSA vs miniposterior approach (MPA).

METHODS

This was a prospective, Institutional Review Board (IRB)-approved investigation from 3 centers. Patients aged 18-70 years with a diagnosis of osteoarthritis were included. Two centers used the MPA, while 1 center the DSA. The DSA uses a 9- to 12-cm incision with its distal extent at the posterosuperior greater trochanter. Dissection into the iliotibial band is avoided, and the capsule at the inferior femoral neck is preserved. All THAs in both cohorts received a cementless, titanium, proximally coated femoral stem and a hemispherical acetabular component.

RESULTS

A total of 42 DSA and 196 MPA THA patients were included. Overall, 43% of patients reported pain in at least 1 of the 8 anatomic areas assessed. There was no difference in the incidence of moderate to severe pain in any anatomic area of interest between the MPA and DSA cohorts (P = .1-.9). Specifically, the incidence of moderate to severe trochanter (17% MPA vs 17% DSA, P = .9), anterior thigh (15% MPA vs 17% DSA, P = .9), and lateral thigh pain (12% MPA vs 12% DSA, P = .9) was nearly identical in both cohorts.

CONCLUSION

This study was unable to demonstrate a difference in the incidence of residual pain after use of a DSA or an MPA approach after THA.

Proximal Femur Bone Density Decreases up to 5 Years After Total Hip Arthroplasty in Young, Active Patients

BACKGROUND

The number of young, active patients undergoing hip arthroplasty continues to increase. The purpose of this study was to evaluate femoral bone density over a 5-year period after hip arthroplasty in young, active patients.

METHODS

A total of 96 patients (103 hips) with a presymptomatic University of California at Los Angeles (UCLA) score ≥6 who had a total hip arthroplasty (THA; 45 hips) or surface replacement arthroplasty (SRA; 58 hips) were prospectively enrolled. UCLA and Harris Hip Scores were collected preoperatively and postoperatively, and dual energy X-ray absorptiometry scans were performed at 6 weeks, 6 months, 1 year, 2 years, and 5 years postoperatively. Bone density was analyzed for 7 traditional Gruen zones in both groups and 6 femoral neck zones in the SRA group. Bone density ratios were calculated for change in bone density compared with baseline.

RESULTS

No differences were present in the preoperative or postoperative UCLA or Harris Hip Scores between the SRA and THA cohorts (P = .07-.7). In the THA group, bone density never returned to baseline during the 5-year period in Gruen zones 1 (91.2% of baseline), 2 (94.8%), 6 (97.3%), and 7 (89.2%). There were no decreases in bone mineral density ratio for the femoral Gruen zones in the SRA group at any interval. Femoral neck bone density after SRA increased on the lateral, tension side up to 5 years postoperatively (P < .0001).

CONCLUSION

Young, active patients undergoing THA with cementless femoral fixation demonstrate reductions in bone density in the proximal femur in Gruen zones 1, 2, and 7 over time.

Residual Symptoms and Function in Young, Active Hip Arthroplasty Patients: Comparable to Normative Controls?

BACKGROUND

Whether patient-reported symptoms and function after total hip and surface replacement arthroplasty in young, active patients compare favorably to those without known hip pathology has not been investigated.

METHODS

A retrospective, multicenter study was designed in which 5 centers contributed patients aged <60 years with a presymptomatic University of California at Los Angeles score ≥6 undergoing hip arthroplasty. Data were collected by an independent, third-party survey center that administered a questionnaire assessing patient satisfaction and function. A "control" population with no prior hip interventions or hip pathology limiting their activity, that met the age and activity criteria, was identified for comparison using multivariate regression analyses.

RESULTS

Eight-hundred six hip arthroplasties (682 total hip arthroplasty, 124 surface replacement arthroplasty) and 158 controls were included. A greater percentage of hip arthroplasty patients were male and aged >50 years which was controlled during multivariate regression analyses. Control patients reported the presence of a limp (15%), stiffness (11%), and pain in the hip (8%), but to a lesser degree than hip arthroplasty patients. Control patients were less likely to report pain in the hip (odds ratio [OR] = 0.4, 95% confidence interval [CI] = 0.2-0.7, P = .006), stiffness in the hip (OR = 0.5, 95% CI = 0.3-0.8, P = .02), and a limp (OR = 0.5, 95% CI = 0.3-0.8, P < .001) vs patients undergoing hip arthroplasty.

CONCLUSION

When interviewed by an independent third party, a substantial portion of control patients did note the presence of hip symptoms, but to a lesser degree than young, active patients undergoing hip arthroplasty.

Incidence and Location of Pain in Young, Active Patients Following Hip Arthroplasty

Persistent pain following hip arthroplasty remains a concern, especially in young, active patients. Four hundred twenty patients less than 60 years of age with a pre-symptomatic UCLA score ≥ 6 (196 total hip arthroplasty [THA]; 224 surface replacement arthroplasty [SRA]) completed a pain-drawing questionnaire investigating the location, severity, and frequency of pain around the hip. At a mean of 2.9 years of follow-up, 40% reported pain in at least one location around the hip. There was no difference in the incidence of groin pain between SRA and THA patients (32% vs. 29%, P=0.6), but THA patients had a greater incidence of anterior (25% vs. 8%, P<0.001) and lateral (20% vs. 10%, P=0.01) thigh pain. A high percentage of young, active patients experience persistent pain following hip arthroplasty.

Comparing the long-term results of two uncemented femoral stems for total hip arthroplasty

327 proximal and 185 extensively coated femoral stems with mean 10-year follow-up were reviewed. Implant survivorship, clinical outcomes, and radiographic analyses were compared. Kaplan-Meier implant survivorship was 97.5% for the proximal, and 98.8% for the extensively coated stem for stem-only revisions at 10-years. The proximally coated stem outperformed on the PCS arm of the SF-12 (P = 0.04) and stiffness arm of the WOMAC (P = 0.03). Otherwise, all clinical outcomes were comparable. Thigh pain incidence was 12.5% and 5.3% for the extensive versus proximally coated groups, respectively (P = 0.007). Radiographic review identified more severe stress shielding (P < 0.001) in the extensively coated stems. This study supports the long-term clinical track record of total hip arthroplasty using two different cementless stem designs.

Radiographic parameters associated with pain following total hip and surface arthroplasty

Pain following total hip arthroplasty (THA) and surface arthroplasty (SRA) remains a significant source of patient dissatisfaction. Two hundred twenty-four SRA and 196 THA patients completed a pain drawing questionnaire and postoperative radiographic measurements of component positioning were performed. In the SRA cohort, 11 of 21 patients (52%) with acetabular uncoverage of ≥5 mm versus 43 of 147 (29%) with acetabular uncoverage of ≤4.9 mm reported groin pain (P=.03). In the THA cohort, an increased distal-third canal fill ratio and a lower canal calcar ratio trended towards a higher incidence of thigh pain (P=.10 and .06), while a decreased mid-third canal fill ratio was associated with increased severity of thigh pain (P=.04). This study identifies associations between radiographic findings and pain following THA and SRA.

Outcomes of long tapered hydroxyapatite-coated stems in revision total hip arthroplasty

The purpose of this study was to evaluate the outcome of femoral component revisions using a long tapered HA coated femoral revision stem. Between 2001 and 2008, 55 femoral component revisions were performed using this stem. Forty-one patients were available for follow up evaluation at average of 59 months. The clinical results were evaluated using the HHS and serial radiographs were evaluated for loosening. The mean HHS was 71 (range 22-100). Three hips required revision of KAR stem (1 aseptic loosening, 1 infection, 1 limb length discrepancy). Only one prosthesis demonstrated radiographic evidence of subsidence. Our study suggests that long tapered HA coated revision femoral components can provide stable fixation and in-growth in cases where there is good proximal femoral bone stock and favorable canal geometry.

Results of a tapered proximally-coated primary cementless stem for revision hip surgery

Nineteen patients (nineteen hips) who had undergone revision total hip arthroplasties using a proximally-coated primary cementless stem were evaluated to determine if a subset of revision arthroplasty patients could be identified where the use of this stem would be appropriate. Of these 19 revisions, 15 were performed for the second stage treatment of infection. The femoral bone deficiency was classified as Paprosky Type I in 6 hips and Type II in 13 hips. At a mean follow-up of 49 months, aseptic stem survivorship was 95% with one revision due to aseptic stem failure. The mean Harris hip scores had improved from a mean of 44 points pre-operatively to 89 points post-operatively. Intra-operatively, there was one complication which included a peri-prosthetic fracture distal to the stem which was treated with an allograft strut with cerclage wires. The authors believe that in type I or II femoral defects, the use of this specific cementless stem may be beneficial in the setting of a revision total hip arthroplasty.

Cementless femoral fixation

Cementless femoral stems are currently preferred for total hip replacement (THR) in the United States. Improvements in stem design, instrumentation and surgical technique have made this technology highly successful, reproducible, and applicable to the vast majority of patients requiring a THR. However, there are ongoing developments in some aspects of stem design that influence clinical results, the incidence of complications and their inherent adaptability in accommodating the needs of individual patients. Here we examine some of these design features.

Cite this article: Bone Joint J 2013;95-B, Supple A:53–6.

Outcomes of short stems in total hip arthroplasty

Short-stem total hip arthroplasty has been proposed as a bone-conserving procedure for the younger and more active population undergoing total hip arthroplasty. Although various short stems are currently available, no studies compare the outcomes between these stems. The aim of the current study was to conduct a systematic review of the clinical and radiographic outcomes of the various short stems that have been approved for use in the United States by the Food and Drug Administration. Outcomes that were assessed included implant survivorship, Harris Hip scores, thigh pain, periprosthetic fracture, subsidence, proximal stress shielding, and the prevalence of stem malalignment and inappropriate implant sizing.

Assessment and management of chronic pain in patients with stable total hip arthroplasty

Total hip arthroplasty (THA) is one of the most successful operations that can restore function and relieve pain. Although a majority of the patients achieve significant pain relief after THA, there are a number of patients that develop chronic pain for unknown reasons. A literature search was performed looking for chronic pain after total hip arthroplasty and stable THA. Major causes of chronic pain include aseptic loosening or infection. However, there is a subset of patients with a stable THA that present with chronic pain which can have several aetiologies. These include soft tissue, bony, neurological, vascular and psychological causes. Essential for successful treatment is the ability to make the correct diagnosis. Thus therapy may be either non-operative or operative. In addition, diagnosis and management often may require multidisciplinary approaches to successfully alleviate chronic pain in these patients with a stable prosthesis.