Comparison of preoperative radiographs and intraoperative findings of fixation of hemispheric porous-coated sockets

Medium- to long-term clinical efficacy of total hip arthroplasty with structural bone grafting for dysplasia of the hip

BACKGROUND

Patients with dysplasia of the hip (DDH) have different degrees of bone defects above and outside the acetabulum, and anatomically reconstructing the acetabular centre of rotation is difficult in primary total hip arthroplasty (THA).

METHODS

From April 2012 to December 2022, 64 patients (64 hips) with DDH treated with THA with structural bone graft in the superolateral acetabulum were selected. The Oxford hip score(OHS), Barthel index (BI), leg length discrepancy, Wibegr central edge-angle(CE), gluteus medius muscle strength, vertical and horizontal distance of the hip rotation center, coverage rate of the bone graft and complications were used to evaluate the clinical effectiveness of the patients.

RESULTS

All patients were followed up for an average of 7.3±1.9 years. The OHS improved significantly after the operation (P<0.001). The postoperative BI was significantly greater than that before operation (P<0.001). The postoperative leg length discrepancy was significantly lower than that before the operation (P<0.001). Postoperative bedside photography revealed that the height and horizontal distance to the hip rotation center were significantly lower after surgery than before surgery (P<0.001). The postoperative CE was significantly greater than that before surgery (P<0.001). No acetabular component loosening or bone graft resorption was found during the postoperative imaging examination.

CONCLUSIONS

The use of biological acetabular cup combined with structural bone graft in the superolateral acetabulum in THA for DDH can obtain satisfactory medium and long-term clinical and radiological results.

Medial Protrusio Technique Versus Structural Autologous Bone-Grafting Technique in Total Hip Arthroplasty for Crowe Type II to III Hip Dysplasia

BACKGROUND

It is unclear whether acetabular reconstruction techniques have any impact on clinical outcomes. This study aimed to determine (1) whether acetabular reconstruction techniques influenced the position of the acetabular cup and (2) whether clinical outcomes based on the acetabular reconstruction techniques differ in patients undergoing total hip arthroplasty (THA) with Crowe II to III developmental dysplasia of the hip.

METHODS

This was a retrospective analysis of prospectively collected data from 69 patients (74 hips) who were treated with cementless THA using medial protrusio technique (MPT) or structural autologous bone-grafting technique (SABT). There were 39 patients (41 hips) included in the MPT group and 30 patients (33 hips) in the SABT group. Clinical and radiographic outcomes were evaluated.

RESULTS

All patients were followed up for at least 3 years. There were similar results between the 2 groups in terms of blood loss, Harris hip score, leg length discrepancy, cup inclination, cup anteversion, and proportion of cup coverage (P > .05). The operative time was significantly longer in the SABT group compared with the MPT group (P < .001). The postoperative vertical center of rotation was significantly higher in the MPT group compared with the SABT group (P = .001), and postoperative horizontal center of rotation was significantly shallower in the SABT group compared with the MPT group (P < .001).

CONCLUSION

The MPT and SABT provide similar clinical and radiographic outcomes in the management of Crowe II to III developmental dysplasia of the hip by cementless THA. However, the MPT has the advantage of a shorter operative time, whereas the SABT is more conducive to placing the acetabular cup in an anatomic position.

LEVEL OF EVIDENCE

Level III, Therapeutic, Case-Control Study.

Influence of avascular necrosis of the femoral head on hip prosthesis integration: a radiological analysis

BACKGROUND

Avascular osteonecrosis of the femoral head (AVN) often results in total hip arthroplasty (THA). The cause for increased THA revision rates among patients with AVN is not yet fully understood.

PURPOSE

To perform a comparative radiological analysis of implant integration between patients with AVN and osteoarthritis (OA).

MATERIAL AND METHODS

After a matched pair analysis of 58 patients, 30 received THA due to OA, 28 due to AVN. X-ray images were evaluated after one week ("baseline") and on average 37.58 months postoperatively ("endline"). The prosthesis was grouped into 10 regions of interest (ROI): seven femoral and three acetabular. Incidence, width, and extent of "radiolucent lines" were measured within each zone.

RESULTS

Between baseline and endline, width and extent progressed more noticeably in all femoral and acetabular zones among patients with AVN. In femoral ROI 1, the width increased in 40% of AVN cases compared to 6.7% of OA cases. For acetabular ROI 3, the width increased in 26.7% of AVN cases compared to no perceived changes in the OA group. No signs of prosthetic loosening were found in the AVN group.

CONCLUSION

The increase of width and extent of radiolucent lines over time in patients with AVN could be a sign of lack of osteointegration. However, prosthetic loosening in absence of clinical symptoms cannot be deduced from radiological findings after medium-term postoperative follow-up. Further long-term studies are required to monitor how radiolucent lines develop in respect to long-term implant loosening. Dependent on bone quality, individually adapted reaming and broaching of the implant site are recommended.

Outcomes of Impaction Bone Grafting in the Management of Acetabular Defects with the Use of Uncemented Acetabular Cups: Do Autografts and Irradiated Femoral Head Allografts Integrate?

Introduction

Acetabular impaction bone grafting (AIBG) has been used widely to reconstruct acetabular defects in complex primary and revision cases. The aim of this study was to look at the outcomes AIBG using either frozen irradiated femoral head allografts or autografts with uncemented acetabular cups.

Method

We retrospectively reviewed 38 patients who had AIBG and uncemented cup reconstruction of the acetabulum performed between 2008 and 2021 for complex primary and revision surgery. Graft incorporation, radiological loosening and cup migration were evaluated in follow-up X-rays.

Result

There were 24 complex primary and 14 revision total hip arthroplasty. Autografts were used in 10 hips with smaller defects, while 28 hips with larger defects required frozen irradiated femoral head allografts. Using Paprosky classification to evaluate acetabular defects; 8 patients were classified as 2A, 12 as 2B, 7 as 2C, 8 as 3A and 3 as 3B. The Kaplan-Meier survival rate for AIBG with uncemented cups in our series is 89.70% in 10 years. Acetabular cup position was anatomically restored in all autograft AIBG cases and in 25 out of 28 in the allograft group. The mean pre-operative Oxford Hip Score (OHS) was 19 (range 10-24) and post-operative OHS was 39 (range 21-48) (p < 0.001).

Conclusions

The mid- to long-term results for AIBG and uncemented acetabular cups is good. With newer and more porous uncemented cups especially revision cups, it may serve as an extended indication to achieve solid fixation together with AIBG technique in managing acetabular defects of ≤ 3A.

Forte ceramic-on-delta ceramic cementless total hip arthroplasty: an 8- to 15-year follow-up study

INTRODUCTION

Forte ceramic head on delta ceramic liner articulation showed satisfactory midterm results without ceramic-related complication. We aimed to investigate the clinical and radiological outcomes of cementless total hip arthroplasty (THA) with forte ceramic head on delta ceramic liner articulation.

MATERIALS AND METHODS

Overall, 107 patients (57 men, 50 women; 138 hips) who underwent cementless THA with forte ceramic head on delta ceramic liner articulation were enrolled. The mean follow-up duration was 11.6 years. For the clinical assessments, Harris hip score (HHS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), presence of thigh pain, and presence of squeaking were evaluated. Radiographs were assessed to search for osteolysis, stem subsidence, loosening of implants. Kaplan-Meier survival curves were evaluated.

RESULTS

The mean HHS and WOMAC improved from 57.1 and 28.1 preoperatively to 81.4 and 13.1 at the final follow-up, respectively. Nine revisions (6.5%) were performed; 5 hips for stem loosening, 1 hip for ceramic liner fracture, 2 hips for periprosthetic fracture, and 1 hip for progressive osteolysis around cup and stem. Thirty-two patients (37 hips) complained squeaking, in which 4 cases (2.9%) were identified as ceramic-related noises. After a mean follow-up period of 11.6 years, 91% (95% CI 87.8-94.2) were free from revision of both femoral and acetabular components due to any reason.

CONCLUSIONS

Cementless THA with forte ceramic-on-delta ceramic articulation showed acceptable clinical and radiological results. Serial surveillance of these patients should be performed due to the possibility of cerami- related complications such as squeaking, osteolysis, and ceramic liner fracture.

Tricalcium Phosphate as a Bone Substitute to Treat Massive Acetabular Bone Defects in Hip Revision Surgery: A Systematic Review and Initial Clinical Experience with 11 Cases

The use of tricalcium phosphate (TCP) as a bone substitute is gaining increasing interest to treat severe acetabular bone defects in revision total hip arthroplasty (rTHA). The aim of this study was to investigate the evidence regarding the efficacy of this material. A systematic review of the literature was performed according to the PRISMA and Cochrane guidelines. The study quality was assessed using the modified Coleman Methodology Score (mCMS) for all studies. A total of eight clinical studies (230 patients) were identified: six on TCP used as biphasic ceramics composed of TCP and hydroxyapatite (HA), and two as pure-phase ceramics consisting of TCP. The literature analysis showed eight retrospective case series, of which only two were comparative studies. The mCMS showed an overall poor methodology (mean score 39.5). While the number of studies and their methodology are still limited, the available evidence suggests safety and overall promising results. A total of 11 cases that underwent rTHA with a pure-phase ceramic presented satisfactory clinical and radiological outcomes at initial short-term follow-up. Further studies at long-term follow-up, involving a larger number of patients, are needed before drawing more definitive conclusions on the potential of TCP for the treatment of patients who undergo rTHA.

Comparison of a Minimally Invasive Tissue-Sparing Posterior Superior (TSPS) Approach and the Standard Posterior Approach for Hip Replacement

Purpose

The purpose of this study is to compare the functional and clinical outcomes, blood loss, complication rate, and hospital length of stay (LOS) of total hip replacement (THR) using a minimally invasive tissue-sparing posterior superior (TSPS) approach and the standard posterior approach.

Materials and Methods

This retrospective, observational, double-centered study included 38 patients undergoing hip replacement. The patents were divided into two groups: control group (19 patients), who underwent surgery with the standard posterior approach, and treatment group (19 patients), who received the same type of implant with ceramic-on-ceramic bearing via the TSPS approach. Hemoglobin level was assessed preoperatively, on first and second postoperative days, and on discharge day. Harris hip score and Western Ontario and McMaster Universities Arthritis Index were used to measure the clinical and functional outcomes. Hospital LOS and incidence of early and late complications were assessed in both groups. Postoperative anteroposterior pelvis X-ray was performed to assess the correct positioning of implants.

Results

Better early clinical outcomes (p = 0.0155), lesser blood loss (p < 0.0001), and reduced hospital LOS (p < 0.0001) were observed in the TSPS group than in the control group. No major adverse effects occurred in both groups, and a satisfactory implant orientation was achieved in all patients.

Conclusions

The TSPS approach is a reliable minimally invasive procedure for THR as it allows an accurate orientation of the components and provides better early postoperative functional outcomes, faster recovery, significantly lower blood loss, and shorter hospital LOS than the standard posterior approach. However, further research is needed to confirm the promising results and cost-effectiveness of the TSPS approach in larger cohorts with a longer follow-up period.

The Clinical and Radiological Outcomes of Subtrochanteric Osteotomy in Crowe Type IV Hip Dysplasia: A Comparison of Three Different Stem Designs

AIMS

The purpose of this study was to determine whether there are differences in clinical and radiographic outcomes among three different stem designs for subtrochanteric osteotomy in Crowe type IV developmental dysplasia of the hip (DDH).

METHODS

A retrospective analysis of prospectively collected data was undertaken from a consecutive series of 37 Crowe type IV DDHs treatment of noncemented total hip arthroplasty with chevron subtrochanteric osteotomy in 30 patients. Patients are divided into three groups, including Ribbed group (using Link Ribbed stem; n = 14), Synergy group (using Synergy stem; n = 9), and Link Classic Uncemented (LCU) group (using LCU stem; n = 14), according to the design of the stem. The clinical and radiographic outcomes were evaluated.

RESULTS

All patients were followed for 36 months. The time of bone union of the LCU stem was significantly longer than that of the Synergy stem (P = 0.02) and the Ribbed stem (P > 0.05); the time of bone union of the Ribbed stem was longer than that of the Synergy stem (P > 0.05). The length of stem in the distal femur of the Ribbed stem (P = 0.000) and the Synergy stem (P = 0.001) is significantly longer than that of the LCU stem. There were three hips with malunion, stem loosening, and varus alignment, which were observed in the LCU stem. None of these were observed in Ribbed and Synergy stems. In total hip arthroplasty with a noncemented stem combined with subtrochanteric femoral osteotomy for Crowe IV DDH, 89.2% hips (33/37) can achieve good and excellent clinical outcomes. There were three hips (1 hip in the Ribbed stem and two in the LCU stem) with fair clinical outcomes and one hip (LCU stem) with poor clinical outcomes.

CONCLUSIONS

Although Ribbed, Synergy, and LCU stems have similar clinical outcomes, the LCU stem has a tendency to a varus position, longer union time, malunion, and stem loosening, when compared with the Ribbed and Synergy stems. We recommend against adoption of the LCU stem for Crowe IV DDH with subtrochanteric femoral osteotomy.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The value of conventional radiographs for diagnosing internal fixation-associated infection

Background

The aim of the study is to  assess the diagnostic value of preoperative conventional radiographs for diagnosing infection associated with internal fixation devices.

Methods

We prospectively collected data of patients undergoing removal of internal fixation devices for any reason. Infection was diagnosed in case of purulence, sinus tract, positive histopathology and/or positive peri-implant tissue or sonication fluid culture. In radiographs radiolucent lines, implant breakage or displacement, or periosteal reaction were assessed. White blood cell count (WBC) and serum C-reactive protein (CRP) were determined at admission.

Results

We included 421 surgeries in 380 patients (median age 53.6 years, range 11–98 years), mainly indicated for infection (24.9%), nonunion (20.0%) and symptomatic implants (13.5%). Radiologic signs of infection included radiolucent lines (11.4%); implant breakage (12.4%) or displacement (10.7%); and periosteal reaction (7.1%). Infection was confirmed in 116 cases (27.6%). Only radiolucent lines (OR = 1.86 [95%CI: 1.00–3.38]) and periosteal reaction (OR = 2.48 [95%CI: 1.17–5.26]) were associated with infection, with a low sensitivity (16.4 and 12.1%, respectively), and high specificity (90.5 and 94.8%, respectively). Preoperative WBC and CRP had a sensitivity of 23.0 and 35.3%, and specificity of 91.7 and 89.5%, respectively.

Conclusions

Radiological signs suggestive of infection were uncommon. Radiolucency and periosteal reaction were associated with infection, though with low sensitivity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04170-3.

Survivorship and Patient-Reported Outcomes of an Uncemented Vitamin E-Infused Monoblock Acetabular Cup: A Multicenter Prospective Cohort Study

BACKGROUND

Addition of vitamin E to polyethylene is theorized to reduce the potential for oxidative wear in acetabular components. This paper presents a multicenter prospective cohort study that reports on outcomes from use of a Vitamin E-infused highly cross-linked polyethylene acetabular cup.

METHODS

Patients were recruited across nine medical institutions. Clinical outcome measures recorded were the Harris Hip Score, visual analogue score for pain and satisfaction. Evidence of implant loosening or osteolysis was collected radiologically. Cup survival and reasons for revision in relevant cases were also recorded. Data collection was undertaken preoperatively, at 6-12 weeks, 6 months, 1 year, 2 years, and 5 years. A total of 675 patients were recruited, with 450 cases available at final review. Data regarding cup survival was available to 8 years and 9 months postoperatively.

RESULTS

Improvements in both the Harris Hip Score and visual analogue score for pain and satisfaction were recorded at all time points, with these being maintained through the length of follow-up. In total, 89% of cups were implanted within the Lewinnek safe zone. A lucent line was identified in one case, with no evidence of acetabular osteolysis observed throughout the follow-up period. Cup survival was 98.9% at 8 years and 9 months. No revisions for aseptic loosening were observed.

CONCLUSIONS

The use of a vitamin E-infused polyethylene acetabular cup demonstrates reassuring patient-reported outcomes, radiological measures, and cup survival at medium to long-term follow-up.

The Fate of Zone 2 Radiolucencies in Contemporary Highly Porous Acetabular Components: Not All Designs Perform Equally

Background

The enhanced frictional resistance of modern ultraporous acetabular components can impede complete seating; however, surgeons expect the enhanced ingrowth surface to resolve polar (zone 2) gaps over time via osseointegration. This study characterized zone 2 radiographic osseointegration in 3 acetabular component designs: 2 highly porous ingrowth and one traditional ongrowth.

Methods

A consecutive cohort of primary total hip arthroplasties was reviewed which utilized 3 different acetabular cup designs: ongrowth titanium with hydroxyapatite (HA), highly porous titanium with machined radial grooves (MRG), and dual-porous titanium substrate with micropore (MP). Radiographic analysis was performed using accepted measurement criteria with particular attention to radiolucent lines.

Results

Seven hundred ninety cases were available for analysis. Initial 1-month radiographs revealed 43.2% of HA, 78.2% of MRG, and 81.0% of MP cups exhibited zone 2 radiolucencies, consistent with incomplete seating. At 1 year, all HA radiolucencies resolved, whereas 46.2% and 34.7% of radiolucencies remained in MRG and MP cups, respectively (P ≤ .005). At minimum 2 years, a significant proportion of zone 2 radiolucencies remained in 46.0% of MRG compared with 23.9% of MP cups and 3.0% of HA cups (P ≤ .007).

Conclusion

The resolution of zone 2 radiolucencies at 1-year and minimum 2-year follow-up signified osseointegration for nearly all HA and most MP cups. Highly porous titanium cups with machined radial grooves demonstrated persistent zone 2 radiolucencies at 1 year and beyond. Given reports of early loosening with this particular acetabular implant, further follow-up is warranted as this study highlights that not all contemporary highly porous metal acetabular components perform equally.

Level of Evidence

III.

Ceramic-on-ceramic articulation in press-fit total hip arthroplasty as a potential reason for early failure, what about the survivors: a ten year follow-up

PURPOSE

In press-fit total hip arthroplasty (THA), primary stability is needed to avoid micromotion and hereby aseptic loosening, the main reason for early revision. High aseptic loosening revision rates of the seleXys TH+ cup (Mathys Medical) with Ceramys ceramic-on-ceramic (CoC) bearing are seen in literature. Since CoC is presumed to overcome long-term wear-related revisions, the reason for early failure of this cup is important to clarify. The aim is to investigate its ten year outcomes and differentiate between potential causes and identify risk factors for aseptic loosening.

METHODS

Retrospective screening of a prospectively documented series of 315 THAs was performed. Primary outcome was cumulative incidence of cup revision due to aseptic loosening. Secondary outcomes were component revision and reoperation. Additionally, potential predictive factors for aseptic loosening were evaluated.

RESULTS

At the median follow-up of 9.7 years [IQR 4.4; 10.3], 48 TH+ (15.2%) were revised due to aseptic loosening. Competing risk analysis showed a ten year cumulative incidence of cup revision due to aseptic loosening of 15.6% (95% CI 12.0-20.2). Stabilization of early revision rates was observed, following a high rate of respectively 81.3% (n = 39) and 95.8% (n = 46) within the first two and three years. No significant predictive factors for aseptic loosening were found.

CONCLUSION

The ten year results of seleXys TH+ cup with Ceramys CoC bearing showed an unacceptable high aseptic loosening rate, which stabilized over time after a high early failure incidence. This could be attributed to a problem with osseointegration during the transition of primary to definitive stability.

Reverse reaming distraction for acetabular reconstruction of chronic pelvic discontinuity

Background

The acetabular distraction technique demonstrates encouraging radiographic and clinical outcomes in treating chronic pelvic discontinuity. The aim of this study is to describe a modified distraction technique and to show our results.

Methods

This study identified 12 cases of chronic pelvic discontinuity undergoing primary or revision total hip arthroplasty (THA) with the technique of reverse reaming distraction between July 2015 and November 2018. All 12 patients had a minimum follow-up of 12 months. Radiographs were reviewed to inspect for component loosening. Clinical assessment included the Harris hip score (HHS) and an ambulatory scoring system.

Results

At the time of final follow-up, no patient was revised. One patient had up to 1 cm migration of the cup in a horizontal or vertical direction and more than 20° change in the abduction angle but was asymptomatic. In the remaining 11 patients, no migration of the component was detected. Both the HHS and ambulatory score showed improvement in all patients. There were no perioperative complications. No postoperative dislocation occurred.

Conclusions

Reverse reaming distraction is a feasible technique in treatment of chronic pelvic discontinuity, with encouraging results at early term. However, ongoing follow-up is required to determine the long-term prognosis in patients receiving this technique.

Fate of the Retained Acetabular Component During Revision Total Hip Arthroplasty: A Meta-Analysis and Systematic Review

BACKGROUND

The aim of this meta-analysis and systematic review is to estimate re-revision rates due to aseptic loosening of retained acetabular components after revision total hip arthroplasty.

METHODS

PubMed, EMBASE, Cochrane Library, and Web of Science were searched until June 11, 2018. Data were extracted by 2 independent investigators and consensus was reached with the involvement of a third investigator. Rates of re-revision due to aseptic loosening from 6 studies were aggregated using random effects model after a logit transformation and were grouped by study and population level characteristics.

RESULTS

An assessment of the re-revision rates of retained acetabular components due to aseptic loosening in revision total hip arthroplasty was reported in 6 studies involving 669 cases. The pooled re-revision rate was 12.6% (95% confidence interval 8.4-18.4) with a mean study follow-up of 8.6 years. The rate of re-revision due to aseptic loosening of retained acetabular components was 6.8% (95% confidence interval 3.4-13.3). In the univariate meta-regression analysis, mean age at index revision surgery was significantly associated with the rate of re-revision due to aseptic loosening (R² = 99.98%, P < .0001).

CONCLUSION

Based on this exploratory analysis, revision hip procedures with retentions of well-fixed acetabular components generally have a low risk of failure during mid-term to long-term follow-ups.

Bone remodelling and integration of two different types of short stem: a dual-energy X-ray - absorptiometry study

PURPOSE

Different kinds of bone preserving hip stems have been created to assure a more physiological distribution of the strengths on the femur. The aim of this research is to evaluate the density reaction of the periprosthetic bone while changing the conformation of the prosthetic implant on dual-energy X-ray - absorptiometry (DXA).

METHODS

This is a prospective, single-centre study assessing bone remodelling changes after implantation of two short hip stems, dividing the patients in two groups according to the implant used: 20 in group A, Metha (B-Braun), and 16 in group B, SMF (Smith and Nephew). All participants had a pre-operative and a post-operative (24 months) DXA evaluating the changes in bone mass density (BMD) occurred in the five Gruen's zones.

RESULTS

Compared to the pre-operative value, differences in BMD percentage were statistically significant only in ROI 4 (p < 0.05), with an increase in both groups (9 and 18%, respectively). The average increase in BMD was of 7.3% and 7.2% in the 2 groups.

CONCLUSION

According to our study, both stems have proved able to provide good load distribution across the metaphyseal region favouring proper system integration. Nonetheless, is certainly needed to perform other studies with longer follow-up and bigger populations to give strength to these conclusions.

Acetabular cup migration after primary cementless total hip arthroplasty in rheumatoid arthritis and its influencing factors: a comparative study with osteoarthritic hip

PURPOSE

To compare the radiographic migration profiles of primary cementless total hip arthroplasty (THA) between patients with rheumatoid arthritis (RA) and those with osteoarthritis (OA).

METHODS

A total of 197 patients (215 hips) who underwent cementless THA for RA or OA between January 2001 and January 2013 and followed up for a minimum of 5.5 years were included. Ninety-four RA patients (109 hips) were compared with 103 OA patients (106 hips). Radiological evaluation was performed for acetabular cup loosening, and cup migration was measured using Einzel-Bild-Röntgen-Analyse (EBRA) software. Multiple variables were assessed to identify influencing factors for cup migration.

RESULTS

Early cup migration was observed in 13 hips (11.9%) in the RA group and four hips (3.8%) in the OA group, showing a significant difference (p = 0.041). Acetabular cup loosening occurred in three cups (2.8%) in the RA group and in one cup (0.9%) in the OA group, showing no significant difference (p = 0.321). Total cup migration was higher in the RA group (2.62 mm) than in the OA group (1.44 mm, p = 0.005). Total cup migration was significantly higher in patients aged < 50 years than in those aged > 50 years (p = 0.005). Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP) antibody influenced total cup migration. Patients with seropositive RA showed significantly higher total cup migration and early cup migration incidence than those with seronegative RA (p = 0.005, p = 0.038, respectively).

CONCLUSIONS

Acetabular cups in primary cementless THAs of RA patients were less stable in terms of cup migration compared with that of OA patients.

Intra- and interrater reliabilities and a method comparison of 2D and 3D techniques in cadavers to determine sacroiliac screw loosening

Sacroiliac (SI) screw loosening may indicate persistent instability, non-union and contribute to pain. Yet, there is no reliable objective measurement technique to detect and monitor SI screw loosening. In 9 cadaveric pelvises one of two SI screw was turned back approximately 20 mm and subsequently assessed by optical measurement, fluoroscopy and a 3D scan using an image intensifier. CTs were segmented and a contour-based registration of the 3D models and the fluoroscopies was performed to measure SI backing out (X-ray module). Three independent observers performed measurements with three repetitions. Deviation of the measurement techniques to the 3D scan, intra- and interrater reliabilities and method equivalence to the 3D scan were assessed. The X-ray module and two fluoroscopic measurement techniques yielded a difference less than 5 mm compared to the 3D scan and equivalence to the 3D scan. Intrarater reliability was for two observers and almost all techniques very good. Three fluoroscopic measurement techniques and optical measurements displayed a very good interrater reliability. The 3D scan and X-ray module yielded the most precise values for SI screw loosening but only the fluoroscopic measurement of the inlet lateral loosening displayed a good reliability and equivalence to the 3D scan.

Two-centre radiological survivorship of acetabular distraction technique for treatment of chronic pelvic discontinuity: mean five-year follow-up

Aims The aim of this study was to examine the results of the acetabular distraction technique in achieving implantation of a stable construct, obtaining biological fixation, and producing healing of chronic pelvic discontinuity at revision total hip arthroplasty. Patients and Methods We identified 32 patients treated between 2006 and 2013 who underwent acetabular revision for a chronic pelvic discontinuity using acetabular distraction, and who were radiographically evaluated at a mean of 62 months (25 to 160). Of these patients, 28 (87.5%) were female. The mean age at the time of revision was 67 years (44 to 86). The patients represented a continuous series drawn from two institutions that adhered to an identical operative technique. Results Of the 32 patients, one patient required a revision for aseptic loosening, two patients had evidence of radiographic loosening but were not revised, and three patients had migration of the acetabular component into a more stable configuration. Radiographically, 22 (69%) of the cohort demonstrated healing of the discontinuity. The Kaplan-Meier construct survivorship was 83.3% when using revision for aseptic acetabular loosening as an endpoint. At the time when one patient failed due to aseptic loosening (at 7.4 years), there were a total of seven patients with a follow-up of seven years or longer who were at risk of failure. Conclusion The acetabular distraction technique demonstrates encouraging radiographic outcomes, with healing of the discontinuity in over two-thirds of our series. This surgical technique permits biological fixation and intraoperative customization of the construct to be implanted based on the pattern of the bone loss identified following component removal. Cite this article: Bone Joint J 2018;100-B:909-14.

The patient-specific Triflange acetabular implant for revision total hip arthroplasty in patients with severe acetabular defects: planning, implantation, and results

Aims

Few reconstructive techniques are available for patients requiring complex acetabular revisions such as those involving Paprosky type 2C, 3A and 3B deficiencies and pelvic discontinuity. Our aim was to describe the development of the patient specific Triflange acetabular component for use in these patients, the surgical technique and mid-term results. We include a description of the pre-operative CT scanning, the construction of a model, operative planning, and surgical technique. All implants were coated with porous plasma spray and hydroxyapatite if desired.

Patients and Methods

A multicentre, retrospective review of 95 complex acetabular reconstructions in 94 patients was performed. A total of 61 (64.2%) were female. The mean age of the patients was 66 (38 to 85). The mean body mass index was 29 kg/m² (18 to 51). Outcome was reported using the Harris Hip Score (HHS), complications, failures and survival.

Results

The mean follow-up was 3.5 years (1 to 11). The mean HHS improved from 46 (15 to 90) pre-operatively to 75 (14 to 100). A total of 21 hips (22%) had at least one complication with some having more than one; including dislocation (6%), infection (6%), and femoral complications (2%). The implant was subsequently removed in five hips (5%), only one for suspected aseptic loosening.

Conclusion

The Triflange patient specific acetabular component provides predictable fixation with complication rates which are similar to those of other techniques.

Cite this article: Bone Joint J 2018;100-B(1 Supple A):50–4.

Clinical safety and wear resistance of the phospholipid polymer-grafted highly cross-linked polyethylene liner

To reduce the production of wear particles and subsequent aseptic loosening, we created a human articular cartilage-mimicked surface for a highly cross-linked polyethylene liner, whose surface grafted layer consisted of a biocompatible phospholipid polymer, poly(2-methacryloyloxyethyl phosphorylcholine). Although our previous in vitro findings showed that poly(2-methacryloyloxyethyl phosphorylcholine)-grafted particles were biologically inert and caused no subsequent bone resorptive responses, and poly(2-methacryloyloxyethyl phosphorylcholine) grafting markedly decreased wear in hip joint simulator tests, the clinical safety, and in vivo wear resistance of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners remained open to question. Therefore, in the present study, we evaluated clinical and radiographic outcomes of poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners 5 years subsequent to total hip replacement in 68 consecutive patients. No reoperation was required for any reason, and no adverse events were associated with the implanted liners. The average Harris Hip Score increased from 38.6 preoperatively to 96.5 5 years postoperatively, and health-related quality of life, as indicated by the Short Form 36 Health Survey, improved. Radiographic analyses showed no periprosthetic osteolysis or implant migration. Between 1 and 5 years postoperatively, the mean steady-state wear rate was 0.002 mm/year, which represented a marked reduction relative to other highly cross-linked polyethylene liners, and appeared to be unaffected by patient-related or surgical factors. Although longer follow up is required, poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners improved mid-term clinical outcomes. The clinical safety and wear-resistance results are encouraging with respect to the improvement of long-term clinical outcomes with poly(2-methacryloyloxyethyl phosphorylcholine)-grafted highly cross-linked polyethylene liners. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2007-2016, 2017.

The diagnostic performance of radiographic criteria to detect aseptic acetabular component loosening after revision total hip arthroplasty

Aims

This study aimed to determine the diagnostic performance of radiographic criteria to detect aseptic acetabular loosening after revision total hip arthroplasty (THA). Secondary aims were to determine the predictive values of different thresholds of migration and to determine the predictive values of radiolucency criteria.

Patients and Methods

Acetabular component migration to re-revision was measured retrospectively using Ein-Bild-Rontgen-Analyse (EBRA-Cup) and manual measurements (Sutherland method) in two groups: Group A, 52 components (48 patients) found not loose at re-revision and Group B, 42 components (36 patients) found loose at re-revision between 1980 and 2015. The presence and extent of radiolucent lines was also assessed.

Results

Using EBRA, both proximal translation and sagittal rotation were excellent diagnostic tests for detecting aseptic loosening. The area under the receiver operating characteristic (ROC) curves was 0.94 and 0.93, respectively. The thresholds of 2.5 mm proximal translation or 2° sagittal rotation (EBRA) in combination with radiolucency criteria had a sensitivity of 93% and specificity of 88% to detect aseptic loosening. The sensitivity, specificity, positive predictive value and negative predictive value (NPV) of radiolucency criteria were 41%, 100%, 100% and 68% respectively. Manual measurements of both proximal translation and sagittal rotation were very good diagnostic tests. The area under the ROC curve was 0.86 and 0.92 respectively. However, manual measurements had a decreased specificity compared with EBRA. Radiolucency criteria had a poor sensitivity and NPV of 41% and 68% respectively.

Conclusion

This study shows that EBRA and manual migration measurements can be used as accurate diagnostic tools to detect aseptic loosening of cementless acetabular components used at revision THA. Radiolucency criteria should not be used in isolation to exclude loosening of cementless acetabular components used at revision THA given their poor sensitivity and NPV. Cite this article: Bone Joint J 2017;99-B:458–64.

Delayed Total Hip Arthroplasty for Failed Acetabular Fractures: The Influence of Initial Fracture Management on Outcome After Arthroplasty

BACKGROUND

Total hip arthroplasty (THA) provides a successful salvage option for failed acetabular fractures. The complexity of arthroplasty for a failed acetabular fracture will depend on the fracture pattern and the initial management of the fracture. Our objective was to compare the midterm outcome of THA between patients who presented with failed acetabular fractures following initial surgical or nonsurgical treatment.

METHODS

Forty-seven patients underwent cementless THA ± acetabular reconstruction following failed treatment of acetabular fractures. Twenty-seven were initially treated by surgery (group A) and 20 had nonsurgical treatment (group B). Intraoperative measures, preoperative and follow-up clinical, radiological, and functional outcomes were compared between the 2 groups.

RESULTS

The mean surgical time, blood loss, and need for blood transfusion were significantly less in group A (P < .05). Acetabular reconstruction to address cavitary or segmental defects was needed in a significantly higher number of patients in group B (P = .006). Significant improvement in modified Merle d'Aubigne and Oxford scores was seen postsurgery in both groups. Acetabular component survival with aseptic loosening as end point was 98%. Overall survival rate with infection, revision, or loosening as end point was 93% at a mean follow-up of 7 years ± 17 months.

CONCLUSION

THA for a failed acetabular fracture is greatly facilitated by initial surgical treatment. Although functional results and survivorship were similar in both groups, failed nonsurgical treatment in complex fractures is associated with migrated femoral head and extensive acetabular defects requiring complex acetabular reconstruction.

Short to Midterm Follow-Up of the Tritanium Primary Acetabular Component: A Cause for Concern

BACKGROUND

Several acetabular components utilizing novel ultraporous metal substrates have been introduced over the past decade. Collectively by design, they have a lower modulus of elasticity to reduce stress shielding, a higher coefficient of friction to enhance interference fit, and ultraporous surfaces to enhance osseointegration. However, little literature exists regarding their clinical performance.

METHODS

This study compared the clinical and radiographic results of 109 hips in 95 patients using a Tritanium primary cup (Stryker, Mahwah, NJ) to an age, body mass index, and gender-matched cohort of 100 patients that received a contemporary cup (Stryker Trident PSL HA).

RESULTS

At an average 4.24 + 1.49 years, implant survivorship of the Tritanium primary cup was 98.2%, with 2 cups revised for failure of osseointegration. One-year radiographs revealed radiolucent and radiosclerotic lines in 2 or more DeLee zones in 30.3% of cups and 3 zone involvement in 8.2%. These proportions increased (40.0% and 17.1%, respectively) at minimum 5-year follow-up. A comparison of 1 year and last follow-up radiographs revealed progression in 13.8%. Tritanium primary components with radiolucency in 2 or more zones exhibited significantly lower HHS at 2 years compared to all Trident peripheral self-locking (PSL) components (P < .0001) and Tritanium primary components with 1 zone or no radiolucency (P = .026). Scanning electron microscopy of a retrieved cup revealed local inflammatory reaction and no evidence of osseointegration.

CONCLUSION

Despite adequate implant survivorship, over one third of Tritanium primary cups had 2 or more zone radiolucency at minimum 5-year follow-up with associated lower Harris hip scores.

Medial Protrusio Technique in Cementless Total Hip Arthroplasty for Developmental Dysplasia of the Hip: A Prospective 6- to 9-Year Follow-Up of 43 Consecutive Patients

BACKGROUND

The medial protrusio technique may be used during total hip arthroplasty (THA) on patients with developmental dysplasia. However, studies have yet to determine whether a cementless cup can be sufficiently stable to withstand loading forces. This study aimed to assess the clinical and radiographic outcomes of this technique. Furthermore, we sought to determine the relationship between the rate of medial protrusion and the incidence of cup loosening.

METHODS

Thirty-nine patients (43 hips) underwent cementless THA between April 2006 and March 2009 by using the medial protrusio technique. These patients participated in a 6- to 9-year follow-up. Their clinical and radiographic data were gathered prospectively.

RESULTS

The average Harris Hip Score improved from 43.1 ± 15.4 points preoperatively to 91.9 ± 12.8 points at the final follow-up (P < .001). The mean height of hip center and the distance of hip center medialization were 2.4 ± 0.6 and 2.5 ± 0.9 cm, respectively. The rate of medial protrusion and the rate of cup coverage were 42.1 ± 12.4% and 96.8 ± 5.1%, respectively. The rate of medial protrusion ranged from 18.3% to 58.3% in 38 hips (group A) and from 61.3% to 68.9% in 5 hips (group B). None of the cups in group A loosened or failed, 2 failures occurred in group B (0% vs 40.0%; P = .011).

CONCLUSIONS

Developmental dysplasia was treated through THA using the medial protrusio technique, which easily achieves a sufficient superolateral host bony coverage of the cup and promotes socket reconstruction at the true acetabulum. The rate of medial protrusion of <60% may be necessary to obtain excellent clinical and radiographic midterm results.

Do alumina matrix composite bearings decrease hip noises and bearing fractures at a minimum of 5 years after THA?

BACKGROUND

Ceramic-on-ceramic bearing couples are theoretically attractive in total hip arthroplasty (THA) because of low wear, but concerns regarding ceramic fracture and squeaking have arisen. Improved material properties of newer alumina matrix composite (AMC) materials, known as Delta ceramics, may reduce these risks. In addition, the use of thinner liners and larger femoral heads may be helpful clinically to lower the rate of dislocation. However, limited short-term clinical results are available and intermediate-term effects are unclear.

QUESTIONS/PURPOSES

(1) What is the frequency of bearing-related complications (dissociation, fracture, and noise) with ceramic-on-ceramic AMC bearings in cementless THA? (2) What other complications arose in patients treated with these bearings? (3) What are the Harris hip scores (HHS) and survivorship free from reoperation and revision at a minimum of 5 years after cementless THA performed with AMC bearings?

METHODS

Over a 9-month period in 2009, one surgeon performed 125 THAs, of which 100 (80% of the total) were performed with cementless, AMC bearings. During the period in question, the exclusion criteria for this implant were primary THAs with severe acetabular or femoral bone defect and revision THAs. Of these, 94 hips (95%) in 91 patients were available for analysis at a minimum of 5 years (range, 5-6 years), because five patients (six hips) had died. Mean age at the time of arthroplasty was 55 ± 14 years. Prostheses with an identical design and Biolox(®) Delta ceramics were used in all patients. Noise was classified into squeaking, clicking, grinding, and popping. Ceramic fracture, dislocation, and any other complications associated with the use of AMC ceramics were also investigated. Clinical evaluation included the modified HHS preoperatively and at each followup. Survivorship free from reoperation and revision was calculated using the Kaplan-Meier method.

RESULTS

Of 91 patients, four developed bearing-related complications, including one with liner dissociation despite initial square seating and three with clicking. No patients had ceramic fractures. A single event of perioperative dislocation occurred in one patient and postoperative periprosthetic fracture occurred in two hips. Mean HHS improved from 56 to 93 points at the final followup (p < 0.001). Survivorship at 5 years free from reoperation and revision was 96.8% and 97.9%, respectively.

CONCLUSIONS

Improved material properties combined with the possible use of larger diameter heads make AMC ceramics a promising alternative bearing option with seemingly comparable clinical outcomes reported by others with conventional ceramic bearings. Despite these encouraging results, however, meticulous technical precautions such as square seating and proper impaction in particular should be taken during liner insertion, because we did observe one liner dissociation and several patients with hip noises.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Long-term results of the uncemented acetabular component in a primary total hip arthroplasty performed for protrusio acetabuli: a fifteen year median follow-up

PURPOSE

Protrusio acetabuli is an uncommon finding that can be seen in patients undergoing primary total hip arthroplasty for arthritis. Uncemented fixation of the acetabular component and bone grafting of the protrusio defect is commonly used as a reconstruction method and has shown good mid-term results. The long-term outcome of these reconstructions warrants further study. The objective of this study was to determine the results of primary total hip arthroplasty (THA) with use of an uncemented acetabular component for protrusio acetabuli in patients followed for a minimum of ten years.

METHODS

Sixty-five hips in 53 patients had a primary THA with uncemented acetabular component for the protrusio acetabuli between 1984 and 2001. There were 53 procedures performed in females (82%) and 12 in males (18%). The mean age at the procedure was 66 years. Acetabular floor reconstruction with use of bone graft was performed in 58 hips (89%). Four patients (five hips) were lost to follow-up less than ten years after the procedure and 25 patients (31 hips) had died during the follow-up period. The median follow-up of living patients that did not have revisions for acetabular component was 15.4 years (range, ten to 24 years).

RESULTS

During the study duration, six hips underwent acetabular component revision: aseptic loosening (three hips), polyethylene wear (two hips), and recurrent instability (one hip). The median Harris hip score for the living patients who did not have an acetabular component revision improved from 55 points pre-operatively to 82 points at the latest follow-up. At 15 years, the estimated survival rate from revision was 70% for the THA: 85.4% for the acetabular component, and 83% for the femoral component. Five unrevised acetabular components had evidence of non-progressive radiolucency.

CONCLUSIONS

In patients undergoing THA with acetabular protrusio, fixation of an uncemented hemispherical shell and use of bone graft as necessary provided satisfactory clinical and radiographic results as well as satisfactory survivorship rates at a median follow-up of 15 years.

Early loosening of a press-fit cup with ceramic-on-ceramic articulation: our early results

INTRODUCTION

In this study, we present the short-term results of the Selexys TH+ cup with the Ceramys inlay which is a press-fit cup with a ceramic-on-ceramic articulation. (Mathys, Bettlach, Switzerland). We compared the results with a retrospective-matched control group with a Delta PF cup (Lima, Udine, Italy), which is also a press-fit cup with a ceramic-on-ceramic articulation.

MATERIALS AND METHODS

257 elective hip arthroplasties with the Selexys TH+ cup in 250 patients placed in 2009 and 2010 were analyzed and compared with a control group retrospective analysis of the uncemented Delta PF cup (Lima, Udine, Italy) placed in 2007 and 2008 in 208 patients (222 hips). Surgical technique and surgeons were identical in both groups.

RESULTS

During a follow-up period of 3-21 months, 19 aseptic loosenings (7.4 %) were found for the Selexys TH+ cup. The survival plotted by a Kaplan-Meier curve shows a 1-year survival of 87.4 %. The Lima Delta PF cup showed a 1-year survival of 99.5 %. Failure analysis showed no clear explanation for this early loosening.

CONCLUSION

The Selexys TH+ cup combined with the Ceramys ceramic-on-ceramic inlay coupling show an unacceptable high early revision rate. Therefore, we advice against using this combination.

Restoration of the hip center during THA performed for protrusio acetabuli is associated with better implant survival

BACKGROUND

Acetabular protrusio is an uncommon finding in hip arthritis. Several reconstructive approaches have been used; however the best approach remains undefined.

QUESTIONS/PURPOSES

Our purposes in this study were to (1) describe the THA survivorship for protrusio as a function of the acetabular component, (2) evaluate survivorship of the cup as a function of restoration of radiographic hip mechanics and offset, and (3) report the long-term clinical results.

METHODS

One hundred twenty-seven patients (162 hips) undergoing primary THA with acetabular protrusio were retrospectively reviewed. The mean age of the patients at surgery was 66±13 years, and the mean followup was 10±6 years (range, 2-25 years).The cup fixation was uncemented in 107 (83 with bone graft) and cemented in 55 hips (14 with bone graft). Preoperative and postoperative radiographs were reviewed for restoration of hip mechanics and offset.

RESULTS

The THA survival from aseptic cup revision at 15 years was 89% (95% CI, 75%-96%) for uncemented compared with 85% (95% CI, 68%-94%) for cemented cups. The risk of aseptic cup revision significantly increased by 24% (hazards ratio, 1.24; 95% CI, 1.02-1.5) for every 1 mm medial or lateral distance away from the native hip center of rotation to the prosthetic head center. Harris hip scores were improved by mean of 27±20 points (n=123) with a higher postoperative score for uncemented bone grafted compared with solely cemented cups (81±16 versus 71±20 points).

CONCLUSIONS

Restoring hip center of rotation using an uncemented cup with or without bone graft was associated with increased durability in our series. There was a 24% increase in the risk of aseptic cup revision for every 1 mm medial or lateral distance away from the native hip center to the prosthetic head center.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Total hip arthroplasty for the sequelae of Legg-Calvé-Perthes disease

BACKGROUND

The durability and risks associated with total hip arthroplasty (THA) for patients with a history of Legg-Calvé-Perthes disease (LCPD) are not well known.

QUESTIONS/PURPOSE

We sought to (1) determine the survivorship of THAs performed for LCPD; (2) assess hip scores and complications associated with THA in this patient population; and (3) compare results between patients who had undergone surgery in childhood with patients who had conservative treatment.

METHODS

We reviewed 99 primary THAs performed in 95 patients with a history of LCPD with minimum 2-year followup (mean ± SD, 8 ± 5 years). Mean age at THA was 48 ± 15 years.

RESULTS

A total of 10 revisions were performed. Using revision for any reason as the end point, the 8-year survival rate was 90% (95% confidence interval [CI], 76%-96%) for cementless implants compared with 86% (95% CI, 57%-96%) for hybrid implants. The mean Harris hip score improved by 31 ± 16 (n = 76). Complications occurred in 16% of hips. The most common major complication was intraoperative fracture (eight femoral, one acetabular). Three patients developed sciatic nerve palsy after a mean lengthening of 2.2 ± 1 cm compared with a mean of 1.4 ± 1 cm in patients with intact sciatic nerve (p = 0.3).

CONCLUSIONS

Cementless THAs for the sequelae of LCPD demonstrate 90% survival from any revision at 8 years followup. THAs for the sequelae of LCPD can be complicated and technically difficult. Intraoperative fractures and nerve injuries are common. Care should be taken to avoid excessive limb lengthening.

Percutaneous acetabuloplasty: a cadaveric study

Periacetabular osteolysis is a common etiology of prosthesis failure in patients who undergo total hip arthroplasty. These lesions are treated by open and, more recently, percutaneous techniques. The purpose of this study was to determine the relevant surface anatomy and bony landmarks in establishing percutaneous access to periacetabular regions and identifying critical at-risk structures in establishing access. Percutaneous access to the periacetabular region was established superiorly, anteroinferiorly, and posteroinferiorly by using 5 L5-to-mid thigh fixed cadaver pelvises with latex-injected vessels using threaded guidewires. Dissection was completed to identify structures at risk, with the distance from the wires recorded to the nearest millimeter. C-arm position for the optimal visualization and placement of guidewires was recorded. Average distance from the pin and the at-risk structures ranged from 11.2 to 38.7 mm. All 3 approaches allowed for safe percutaneous access to the periacetabular regions without injuring significant anatomical structures. This study established safe starting points and orientation for guidewires and radiograph projections associated with percutaneous access to the periacetabular regions. The findings in this study will be useful for developing minimally invasive approaches to these regions for the treatment of osteolytic lesions of diverse etiology. However, a biomechanical evaluation of the impact of these bony channels on the strength of pelvis under physiological and unanticipated loading must be performed before this technique can be safely translated to clinical practice.

Analysis of migration of press-fit porous-coated acetabular components with medial lucencies using Ein-Bild-Roentegen-Analyse

A total of 136 patients who underwent total hip arthroplasty (154 hips) with press-fit acetabular components were evaluated for the presence of medial radiographic lucencies. Thirty patients (22.1%) demonstrated radiolucencies greater than 1 mm in zone 2 on initial postoperative films. Ein-Bild-Roentegen-Analyse (EBRA) was used to evaluate component migration over a 5-year follow-up period. Migration, measured by EBRA, was not observed during the first 6 months when the radiolucencies were noted to disappear. After 2 years, the mean total migration was 0.8 mm, and at 5 years, it was 1.6 mm. Our results indicate that disappearance of a medial radiolucency seen on early postoperative radiographs is not associated with component migration, which supports the concept that the medial radiolucency fills in with bone or represents bony remodeling around a stable implant.

Repeat 2-stage exchange for infected total hip arthroplasty: a viable option?

We investigated whether performing a repeat 2-stage exchange eradicates infection in patients who previously underwent 2-stage treatment for an infected total hip arthroplasty. We identified 15 patients who had failed a 2-stage total hip arthroplasty and underwent a planned repeat 2-stage between 2000 and 2009. Of the 15 patients, 8 were treated with a complete 2-stage procedure, whereas the remaining 7 patients were treated only with a first-stage resection of the infected implant. Of the 8 patients who underwent complete 2-stage exchange, 1 died because of in-hospital complications, and 1 had a recurrent infection. Repeat infection is highly associated with resistant organisms, obesity, and poor patient health. Of the 7 patients who underwent resection without reimplantation, 3 had a recurrent infection. Our data suggest that if infection can be adequately controlled after repeat resection of the joint prosthesis, reimplantation is a reasonable option.

Early failure of articular surface replacement XL total hip arthroplasty

The ASR (articular surface replacement) XL (DePuy, Warsaw, Ind) metal-on-metal hip arthroplasty offers the advantage of stability and increased motion. However, an alarming number of early failures prompted the evaluation of patients treated with this system. A prospective study of patients who underwent arthroplasty with the ASR XL system was performed. Patients with 2-year follow-up or any revision were included. Failure rates, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and radiographs were evaluated. Ninety-five patients (105 hips) were included. There were 16 revisions. Thirteen (12%) were aseptic acetabular failures. Eight were revised for aseptic loosening; 4, for metallosis; 1, for malposition; 2, for infection; and 1, for periprosthetic fracture. Mean time to revision was 1.6 years (0.18-3.4 years). The ASR XL with a revision rate of 12% is the second reported 1 piece metal-on-metal system with a significant failure rate at early follow-up. This particular class of implants has inherent design flaws that lead to early failure.

The use of modular femoral head trials to centre the Explant blade facilitates retrieval of well-fixed acetabular components with minimal bone loss

BACKGROUND

The Zimmer-Explant system has made removal of a well-fixed monobloc acetabular component less challenging, but depends on the presence of an intact liner for instrument centralization. We report the outcome of 15 hips with well-fixed, cementless resurfacing sockets, which were removed using a modification of the existing method. We conclude that the existing Explant system combined with modular trial heads allows safe removal of monobloc shells with minimal bone loss.

METHODS

Fifteen patients who underwent removal of a well-fixed, acetabular resurfacing component at the time of revision arthroplasty were identified from the unit's prospective arthroplasty database from 2005.

RESULT

The final reamer used during reconstruction was only 1 or 2 mm larger than the outer diameter of the revised cup.

Correlation of Technetium-99m scintigraphy, progressive acetabular osteolysis and acetabular component loosening in total hip arthroplasty

In total hip arthroplasty (THA) Technetium scintigraphy can help to diagnose a loose implant by detecting elevated osteoblastic activity. It has been used for timing the revision of cemented implants. In uncemented cups progressive radiological acetabular osteolysis can be present before loosening accurs, but it is probably unwise to await cup loosening before embarking on revision. We explored the possible relationship between such osteolysis and positive findings on technetium scintigraphy, to see if the technique could predict the need for revision. Between 1990 and 1996 500 hydroxyapatite-coated hip prostheses were implanted (follow-up range: 9-15 years), and technetium scintigraphy and plain radiography were performed annually postoperatively. 32 cups were revised for progressive acetabular osteolysis. We compared the introperative findings at revision with the pre-operative scintigraphic and radiographic results. The sensitivity and specificity for diagnosing progressive acetabular osteolysis by technetium scintigraphy were 34% and 0% respectively. The sensitivity and specificity of the technique for detecting loosening were 38% and 73% respectively. The sensitivity and specificity of technetium scintigraphy for detection of a either loosening or progressive acetabular osteolysis are worse than reported for plain radiography. Despite negative scintigraphy, there may be progressive bone loss at a critical level. Scintigraphy has no additional value to plain radiography as a reliable indicator for timing cup revision in the process of progressive acetabular osteolysis.

Survivorship of Conserve® Plus monoblock metal-on-metal hip resurfacing sockets: radiographic midterm results of 580 patients

Resurfacing systems use press-fit, monoblock, cobalt chrome alloy acetabular sockets because of the material's ability to withstand stresses while accommodating a large femoral head. Despite the widespread use of these types of sockets for both hip resurfacing and total hip replacement, there is a paucity of literature assessing the outcomes of these cups in particular. The 10 year survivorship of the Conserve® Plus monoblock acetabular component used in this study was 98.3% with small pelvic osteolytic lesions suspected in only 2.3%. This study highlights the excellent radiographic survivorship profile of the Conserve® Plus socket.

Large acetabular defects can be managed with cementless revision components

BACKGROUND

Optimal techniques for acetabular revision in the setting of major pelvic osteolysis have not been established. Bilobed components, structural grafts, and reinforcement cages have demonstrated 10-24% midterm failure rates. While cementless hemispherical components have been utilized to treat large acetabular defects, most reports have not focused specifically on patients with extensive deficiencies.

QUESTIONS/PURPOSES

We report midterm clinical scores, component revisions, and complications following focal bone grafting and cementless acetabular revision in cases with major periacetabular osteolysis.

METHODS

We identified 30 patients (32 hips) who underwent cementless acetabular revision to treat massive acetabular bone loss at an average followup of 53 months. We excluded three patients lost to followup and two patients who died prior to minimum 24 month followup. Harris Hip Scores were assessed before and after surgery. Postoperative radiographs were evaluated for graft incorporation and component migration. Component revision and component migration are reported as failures.

RESULTS

Mean Harris Hip Score improved from 52.5 (range, 17.7-90.7) to 87.3 (range, 25.3-100) points. Three hips (9%) were revised for aseptic loosening. Three components (10.7%) demonstrated radiographic migration, but were not revised. Complete graft incorporation was seen in 17 cases (68%). There were five major complications (14%).

CONCLUSIONS

Cementless acetabular fixation and bone grafting result in clinical scores and survivorship comparable to other options at midterm followup, with potential for biological fixation.

LEVEL OF EVIDENCE

Level IV, clinical research study. See the Guidelines for Authors for a complete description of levels of evidence.

[Reconstruction of large acetabular defects using trabecular metal augments]

OBJECTIVE

Revision of cup and reconstruction of original center of rotation. High primary and secondary stability. Prevention of additional bone loss.

INDICATIONS

Osseous defects at the anterior-cranial, cranial and posterior-cranial rim of acetabulum. Larger cavitary, medial or oval defects (Paprosky IIb-IIIb). Segmental defects (anterior column up to half of host bone, posterior column up to one third of host bone).

CONTRAINDICATIONS

Infection of total hip arthroplasty. Pelvic discontinuity (Paprosky IV).

SURGICAL TECHNIQUE

Exposure of acetabulum and detection of defects. Complete removal of soft tissue from acetabulum, reaming of sclerotic bone, if necessary. Adaptation of trial augments to close an oval defect to a round defect and to reach an uncontained defect, respectively. Adaptation of trial cup. In case of sufficient stability, fixation of final augment with two or three screws in cranial bone stock. The screws should be directed to iliosacral joint. Augmentation with allogenic bone chips is possible in the region of wedge and acetabulum as well. Sealing of rough augment surface with bone cement. Implantation of cup, fixation with screws. Application of insert.

POSTOPERATIVE MANAGEMENT

Depending on bone defects, full weight bearing is possible. In cases of severe bone defects, reduction of weight bearing to 20 kg for 6 weeks is recommended. Postoperative physiotherapy is possible in most cases.

RESULTS

Between 2005 and 2007, 38 patients with acetabular defects type IIIa und IIIb according to Paprosky underwent reconstruction using the TMT system (Trabecular Metal Technology). After 25 months, a significant functional improvement was seen in all patients. The Merle d'Aubigné Score increased from 6 points preoperatively to 13 points postoperatively, the Harris Hip Score from 29 to 78 points. Two revisions were necessary because of loosening or migration of the cup.

Wear and range of motion of different femoral head sizes

Femoral head sizes greater than 32 mm are more prevalent with current total hip arthroplasty. We hypothesized that linear wear rates of Durasul highly cross-linked polyethylene would not differ with different head sizes. We also compared the range of motion of the hip. Ninety-four consecutive arthroplasties in 84 patients were studied for a mean 3.6 +/- 0.7 years. There was no statistical difference in linear wear rates and annual or total penetration rates when 28-mm and 32-mm heads were compared to 38-mm and 44-mm heads. Volumetric wear was 12.4 mm(3)/y higher with bigger heads. Range of motion did not differ. Larger femoral head sizes show no evidence of an accelerated wear pattern when used with Durasul.

[Five-year survival rate of the Allofit titanium press-fit cup]

BACKGROUND

The Allofit titanium press-fit cup has become the best-selling cementless acetabular implant in Germany, with approximately 30,000 implants sold in 2007. However, only a limited number of scientific publications - mostly from the development centres in Austria - support this success on the market.

METHODS

At our institution in 1999-2000, 174 total hip replacements were performed using the Allofit cementless press-fit cup. At a mean follow-up of 5.3 years (range 40-85 months), 154 patients were evaluated clinically and radiographically, representing a follow-up rate of 89%.

RESULTS

The 5-year survival rate was 98.1% (95% CI: 95.8-100%), with revision for any reason as an end point. Three cups were revised (aseptic loosening with one, and two septic complications). The average Harris hip score was 89.1+/-13.7 in all unrevised patients.

CONCLUSION

We confirm the excellent survival rates of the Allofit cup as reported by the development centres, supporting the ongoing use of the cup at our institution.

Failure of the Durom Metasul acetabular component

Large-diameter metal-on-metal articulations reportedly provide better stability and range of motion than smaller diameter bearings. We therefore asked whether a large-diameter (44- to 50-mm) metal-on-metal articulation (Durom) would eliminate dislocation and provide similar functional scores and clinical and radiographic failure rates as those with 28-mm articulation. We prospectively followed 181 patients (207 hips) who had a large-diameter articulation implanted between May 2006 and November 2007. We compared these patients with a historical control of 54 patients who had a small-diameter (28-mm Metasul) articulation. All patients had a Harris hip score and a self-assessment of outcome and radiographic followup. The minimum followup was 1 year (mean, 1.6 years; range, 1-2 years). During the followup period, we performed revisions on 29 patients (30 hips [15%]) with 21 of 29 (72%) having radiographic criteria of loosening. Thirteen retrieved cups and acetabular tissue were examined histologically. Twenty-eight of 151 unrevised patients had radiographic impending failure; 12 without revision had clinical failure. Eight patients (nine hips) had both clinical failure and impending radiographic failure. Cup inclination was 41.3 degrees +/- 5.4 degrees and anteversion was 20.2 degrees +/- 7 degrees. The revision rate and quality of clinical results were unacceptable as compared with our historical controls. We do not recommend use of the Durom implant.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

One surgeon's experience with the 2-incision technique for total hip arthroplasty

This study's purpose was to analyze the complications that occurred during and after one surgeon's first 200 two-incision total hip arthroplasties. Complications included 4 intraoperative femur fractures, 4 postoperative femur fractures, 2 nondisplaced greater trochanter fractures greater than 2 cm, 14 asymptomatic greater trochanter fractures 2 cm or less, 1 malpositioned cup requiring revision, 1 loose stem, 7 cases of heterotopic ossification of grade 2 or higher, 4 dislocations, 1 superficial infection, 80 lateral femoral cutaneous nerve neuropraxias (78 resolved within 6 weeks), and 4 femoral nerve neuropraxias (3 resolved within 12 weeks). This study shows that the 2-incision technique can be performed with a low risk of major complications, and patients can expect reduced tissue trauma and faster rehabilitation. When carefully sought out, minor complications were not uncommon after 2-incision total hip arthroplasty.

Functional variants of the P2RX7 gene, aseptic osteolysis, and revision of the total hip arthroplasty: a preliminary study

Periprosthetic osteolysis (OL) is a major long-term complication of the total hip arthroplasty (THA), which can result in aseptic loosening and revision surgery. Purinergic receptor P2X, ligand-gated ion channel 7 (P2RX7) is an important regulator of inflammation and bone turnover. We were therefore interested in whether functional variants of the P2RX7 gene may be associated with OL and risk of THA failure. A total of 205 unrelated Czech patients with cementless-type THA were stratified according to the severity of acetabular OL and revision of THA. Four "loss-of-function" P2RX7 single nucleotide polymorphisms (SNPs), namely Glu496Ala, Ile568Asn, Arg307Gln, and null allele (rs35933842), were genotyped by polymerase chain reaction with sequence-specific primers (PCR-SSP). No significant association of P2RX7 variants with severity of OL was observed. The carriers of rare variants P2RX7 568Asn, 307Gln and null allele, all causing complete loss of P2RX7 function, tended to be overrepresented among patients with THA revision (9.6%) by comparison with those with unrevised functional prosthesis (2.1%, p = 0.09). Furthermore, the carriage of the P2RX7 307Gln allele was associated with greater cumulative hazard of THA revision (p = 0.02). In this preliminary study, we could nominate but not clearly demonstrate rare P2RX7 loss-of-function variants being associated with THA failure. Investigation in large THA cohorts is therefore warranted.

Variation in cytokine genes can contribute to severity of acetabular osteolysis and risk for revision in patients with ABG 1 total hip arthroplasty: a genetic association study

BACKGROUND

The differences in total hip arthroplasty (THA) survivorship may be influenced by individual susceptibility to periprosthetic osteolysis. This may be driven by functional polymorphisms in the genes for cytokines and cytokine receptors involved in the development of osteolysis in THA, thereby having an effect on the individual's phenotype.

METHODS

We performed a study on 22 single-nucleotide polymorphisms (SNPs) for 11 cytokines and two cytokine receptor candidate genes for association with severity of acetabular osteolysis and risk to failure in THA. Samples from 205 unrelated Caucasian patients with cementless type THA (ABG 1) were investigated. Distribution of investigated SNP variants between the groups of mild and severe acetabular osteolysis was determined by univariate and multivariate analysis. Time-dependent output variables were analyzed by the Cox hazards model.

RESULTS

Univariate analysis showed: 1) TNF-238*A allele was associated with severe osteolysis (odds ratio, OR = 6.59, p = 0.005, population attributable risk, PAR 5.2%); 2) carriers of the IL6-174*G allele were 2.5 times more prone to develop severe osteolysis than non-carriers (OR = 2.51, p = 0.007, PAR = 31.5%); 3) the carriage of IL2-330*G allele was associated with protection from severe osteolysis (OR = 0.55, p = 0.043). Based on logistic regression, the alleles TNF-238*A and IL6-174*G were independent predictors for the development of severe acetabular osteolysis. Carriers of TNF-238*A had increased cumulative hazard of THA failure according to Cox model (p = 0.024). In contrast, IL2-330*G allele predicted lower cumulative hazard of THA failure (p = 0.019).

CONCLUSION

Genetic variants of proinflammatory cytokines TNF-alpha and IL-6 confer susceptibility to severe OL. In this way, presence of the minor TNF allele could increase the cumulative risk of THA failure. Conversely, SNP in the IL2 gene may protect carriers from the above THA complications.

Use of the extended trochanteric osteotomy in treating prosthetic hip infection

The goal of this study is to evaluate the efficacy of using an extended trochanteric osteotomy (ETO) as part of a 2-stage exchange procedure for prosthetic hip infections. Twenty-three consecutive infected total hip arthroplasties in which an ETO was used as part of a 2-stage exchange procedure were retrospectively reviewed. An ETO was used when the femoral component could not be extracted using standard techniques. Clinical and radiographic parameters were evaluated at an average of 49 months of follow-up. Postoperatively, 20 of 23 (87%) patients had resolution of their infection, with healing of the ETO in 22 of 23 patients at a mean of 11.5 weeks. Preoperative modified D'Aubigne and Postel score means of 2.4 for pain and 2.6 for walking ability significantly improved (P < .001) to 5.3 and 4.9. Use of an ETO as part of a 2-stage exchange arthroplasty can be performed safely and effectively in appropriately selected cases.

Poor survival of ABG I hip prosthesis in younger patients

BACKGROUND

Hydroxyapatite coated (HAC) hip implants have been used in clinical practice for more than two decades. However, the majority of studies have reported only intermediate term outcomes that are not reliable for predicting long-term behavior in all implants. The aim of this study was to determine the performance of HAC total hip arthroplasty in younger patients over a 10-year follow-up period.

METHODS AND RESULTS

This was an observational retrospective study of a 137 consecutive hips with the ABG I prosthesis. Of these, 128 were available for the last investigation. Median duration of follow-up was 10.9 years. The mean age at time of index surgery was 46+/-6.7 years. Probability of implant survival was estimated using the Kaplan-Meier method. The overall 12-year cumulative survival was 0.55 (95% CI, 0.443-0.659). Periprosthetic osteolysis (57 %) was the most frequent reason for failure followed by aseptic loosening (28 %). When only aseptic loosening was included in the analysis, the same figures for cup and stem were 0.873 (95% CI, 0.808-0.938) and 0.992 (95% CI, 0.976- 1.0), respectively. Patients with a smaller cup size were those at high risk for revision due to wear-related complications (odds ratio, OR=4.3; 95% CI, 1.734-10.555).

CONCLUSION

This study reports one of the poorest 12-year survivorship data for cementless acetabular component in the literature. The main reason for premature failure was osteolysis, strongly related to high wear rate of polyethylene.