Predictive outcomes of revision total hip replacement--a consecutive series of 1176 patients with a minimum 10-year follow-up

Periprosthetic fracture following anterior approach or dislocation after posterior approach: which one is the lesser evil?

INTRODUCTION

The most common approaches in total hip arthroplasty (THA) have different complication profiles; anterior-approach (AA-THA) has an increased risk of periprosthetic fractures (PPF); posterior-approach (PA-THA) is associated with higher dislocation risk. However, the relative severity of one versus the other is unknown. This study aims to compare outcome of patients who suffered PPF after AA-THA with those that sustained dislocation after PA-THA.

METHODS

This is a retrospective, single-center, multi-surgeon, consecutive case-series of primary THA patients. In a cohort of 9867 patients who underwent THA, 79 fulfilled the approach-specific, post-operative complication criteria, of which 44 were PPF after AA-THA and 35 with dislocation after PA-THA (age 67.9 years (range: 38.0-88.1), 58.2% women). Outcome included complication- and revision- rates, and patient-reported outcomes including Oxford Hip Score (OHS).

RESULTS

At 5.8 years follow-up (range: 2.0-18.5), reoperation was more common in the dislocation after PA-THA group (23/35 vs. 20/44; p = 0.072). Change of surgical approach occurred in 15/20 of patients with PPF after AA-THA, but none in those with dislocation after PA-THA. Following re-operation, complication rate was greater in the PPF group (9/20 vs. 4/23; p = 0.049). At latest follow-up, OHS were superior in the PPF after AA-THA group [42.6 (range: 25.0-48.0) vs. 36.6 (range: 21.0-47.0); p = 0.006].

CONCLUSION

Dislocation following PA-THA is more likely to require revision. However, PPF following AA-THA requires more often a different surgical approach and is at higher risk of complications. Despite the increased surgical burden post-operative PROMs are better in the peri-prosthetic fracture group, especially in cases not requiring reoperation.

LEVEL OF EVIDENCE

III, case-control study.

How to Manage Metallosis: A Retrospective Cohort Analysis after Revision Hip Surgery

BACKGROUND

Adverse local tissue reactions to metal debris are due to a metal-on-metal bearing complication caused by micromotions at modular interfaces that induce corrosion of the protective oxide layer. This process could lead to wear, fretting, and abrasion with the release of metal ions locally and systemically, which may cause adverse local reactions in nearby tissues. The aim of this study is to describe a series of patients with painful local adverse tissue reactions secondary to corrosion at the modular neck-body interface, to document the clinical presentation, diagnostic workup, and surgical findings of our research, and to search for a possible correlation between metallosis and infection.

METHODS

A retrospective study of patients with adverse local tissue reactions due to metal surface corrosion was performed. Blood samples were collected to identify erythrocyte sedimentation rate, C reactive protein, and procalcitonin, and a magnetic resonance imaging protocol was performed.

RESULTS

Serum cobalt and chromium levels of the 43 patients tested were significantly higher on average. However, both erythrocyte sedimentation rate and C-reactive protein were significantly elevated. Magnetic resonance imaging showed adverse reactions to metal debris with large soft tissue masses and surrounding tissue damage.

CONCLUSIONS

Corrosion in hip prosthesis can lead to the release of metal ions and debris locally and systemically, resulting in local soft tissue changes. A "tumor-like" debridement can reduce this complication.

[Postoperative outcomes and survival rates after aseptic revision total hip arthroplasty : What can patients expect from revision surgery?]

BACKGROUND

In 2020, more than 14,000 aseptic revision procedures for total hip arthroplasty (THA) were registered in Germany. Patient expectations of revision hip arthroplasty are not substantially different from expectations of primary hip replacement.

OUTCOME

However, revision surgery is associated with increased complication rates and a higher proportion of dissatisfied patients. In particular, poorer postoperative function and mobility as well as increased pain levels following revision THA have been described compared to the outcome after primary THA. Quality of life and return-to-work can also be impaired.

SURVIVAL RATE

Implant survival is influenced by age, BMI, and comorbidities of the patients, but also by the size and complexity of bone defects, the extent of periprosthetic soft tissue compromise and the choice of revision implant(s). In addition, the number of previous revision surgeries inversely correlates with the survival rates. Previous revisions have been shown to be associated with increased risks of aseptic loosening, instability and periprosthetic infection.

Survivorship of the retained femoral component after revision total hip arthroplasty: A systematic review and meta-analysis

Objective

This systematic review and meta-analysis aimed to estimate re-revision rates of retained femoral components after revision of total hip arthroplasty (THA).

Methods

Papers were searched in the PubMed, Embase, Web of Science, and Cochrane Library databases with predetermined keywords from January 2000 to January 2022. The studies reporting the re-revision rates of retained stems after revision THA were identified. Pooled rates of re-revision for any reason and aseptic loosening were calculated using a random-effects model or a fixed-effects model based on the results of heterogeneity assessment after the Freeman–Tukey double-arcsine transformation. A meta-regression was performed to explore potential sources of heterogeneity.

Results

There were 20 studies with 1,484 hips that received the isolated cup revision with the femoral component retained. The pooled re-revision rate of retained stems was 1.75% [95% confidence interval (CI) 0.43%–3.65%]. The re-revision rate of retained stems due to aseptic loosening was 0.62% (95% CI, 0.06%–1.55%). The meta-regression showed that the fixation type (cemented or cementless) was related to the re-revision rate for any reason and the re-revision rate for aseptic loosening.

Conclusion

Based on the existing evidence, the isolated cup revision with a stable stem in situ yields low re-revision rates. The cement status of retained stems may influence the survivorship of stems.

[Planning revision hip arthroplasty : What are the structural requirements?]

The results of many studies and register reports show that the frequency of primary hip arthroplasty per hospital, but also per surgeon, influence the outcome. In the large spectrum of revision hip arthroplasty volume-outcome effects have also partially been proven. It is obvious that with the increasing complexity of revision surgery and comorbidities, higher demands exist concerning collaborating disciplines as well as training and intervention frequency of the surgical team. Further aspects regarding organisation and structure such as the availability of specific revision implants and instruments must be ensured. In order to provide sustainable resources for revision surgery in an arthroplasty centre, organization of education and training for staff members in different disciplines and working levels must be ensured without quality impairment.

Patient-reported outcome measures, complication rates, and re-revision rates are not associated with the indication for revision total hip arthroplasty : a prospective evaluation of 647 consecutive patients

AIMS

The aim of this study was to explore the relationship between reason for revision total hip arthroplasty (rTHA) and outcomes in terms of patient-reported outcome measures (PROMs).

METHODS

We reviewed a prospective cohort of 647 patients undergoing full or partial rTHA at a single high-volume centre with a minimum of two years' follow-up. The reasons for revision were classified as: infection; aseptic loosening; dislocation; structural failure; and painful THA for other reasons. PROMs (modified Oxford Hip Score (mOHS), EuroQol five-dimension three-level health questionnaire (EQ-5D-3L) score, and visual analogue scales for pain during rest and activity), complication rates, and failure rates were compared among the groups.

RESULTS

The indication for revision influenced PROMs improvement over time. This finding mainly reflected preoperative differences between the groups, but diminished between the first and second postoperative years. Preoperatively, patients revised due to infection and aseptic loosening had a lower mOHS than patients with other indications for revision. Pain scores at baseline were highest in patients being revised for dislocation. Infection and aseptic loosening groups showed marked changes over time in both mOHS and EQ-5D-3L. Overall complications and re-revision rates were 35.4% and 9.7% respectively, with no differences between the groups (p = 0.351 and p = 0.470, respectively).

CONCLUSION

Good outcomes were generally obtained regardless of the reason for revision, with patients having the poorest preoperative scores exhibiting the greatest improvement in PROMs. Furthermore, overall complication and reoperation rates were in line with previous reports and did not differ between different indications for rTHA. Cite this article: Bone Joint J 2022;104-B(7):859-866.

Cost-effectiveness of dual-mobility components in patients with displaced femoral neck fractures

AIMS

Total hip arthroplasty (THA) with dual-mobility components (DM-THA) has been shown to decrease the risk of dislocation in the setting of a displaced neck of femur fracture compared to conventional single-bearing THA (SB-THA). This study assesses if the clinical benefit of a reduced dislocation rate can justify the incremental cost increase of DM-THA compared to SB-THA.

METHODS

Costs and benefits were established for patients aged 75 to 79 years over a five-year time period in the base case from the Canadian Health Payer's perspective. One-way and probabilistic sensitivity analysis assessed the robustness of the base case model conclusions.

RESULTS

DM-THA was found to be cost-effective, with an estimated incremental cost-effectiveness ratio (ICER) of CAD $46,556 (£27,074) per quality-adjusted life year (QALY). Sensitivity analysis revealed DM-THA was not cost-effective across all age groups in the first two years. DM-THA becomes cost-effective for those aged under 80 years at time periods from five to 15 years, but was not cost-effective for those aged 80 years and over at any timepoint. To be cost-effective at ten years in the base case, DM-THA must reduce the risk of dislocation compared to SB-THA by at least 62%. Probabilistic sensitivity analysis showed DM-THA was 58% likely to be cost-effective in the base case.

CONCLUSION

Treating patients with a displaced femoral neck fracture using DM-THA components may be cost-effective compared to SB-THA in patients aged under 80 years. However, future research will help determine if the modelled rates of adverse events hold true. Surgeons should continue to use clinical judgement and consider individual patients' physiological age and risk factors for dislocation. Cite this article: Bone Joint J 2021;103-B(12):1783-1790.

Short uncemented femoral component for hip revision: prognosis and risk factors associated with failure

Background

The application of short femoral stems is partially restricted in revision surgery. This study will demonstrate the therapeutic effect and unsuitable situation for short stem revision.

Methods

Demographic characteristics of all patients were recorded in detail (Table 1). Anteroposterior view radiographic examinations of proximal femur are necessary before and after the operation for patients. The primary outcome of interest was the survival rate of the femoral stem at the final follow-up. Risk factors for failure were also investigated. The secondary outcomes of interest included the Harris hip score, excellent to good rate and incidence of complications. The Mann–Whitney U test was performed for comparisons between continuous variables. The chi-square test was performed for comparisons between categorical variables. Cox regression analysis was used to assess the association between potential risk factors and the failure of revision surgery.

Results

A total of 381 patients with short stems were retrospectively reviewed. There were 188 males and 193 females. The average age and body mass index before revision surgery were 58.85 ± 13.46 years and 23.72 ± 3.40 kg/m², respectively. The mid-term survival rate of the short femoral component was 94.23%. The prognosis and complications of patients between the two groups were compared. There was no significant difference between the two groups in the Harris score, complication incidence or survival rate of the femoral component. The strongest risk factor in this study was intraoperative periprosthetic femoral fracture during revision surgery (HR = 5.477, 95% CI = 2.156–13.913).

Conclusion

Three risk factors for failure were identified: ageing, osteoporosis and intraoperative periprosthetic femoral fracture during revision surgery. Therefore, a short femoral stem should be implanted in patients with these risk factors with additional caution.

Low Hospital Volume Increases Re-Revision Rate Following Aseptic Revision Total Knee Arthroplasty: An Analysis of 23,644 Cases

BACKGROUND

Along with rising numbers of primary total knee arthroplasty (TKA), the number of revision total knee arthroplasties (R-TKAs) has been increasing. R-TKA is a complex procedure requiring special instruments, implants, and surgical skills. Therefore it is likely that hospitals with more R-TKAs have more experience with this type of surgery and therefore fewer complications. The purpose of this study is to evaluate the relationship between hospital volume and re-revision rate following R-TKA.

METHODS

Using nationwide healthcare insurance data for inpatient hospital treatment, 23,644 aseptic R-TKAs in 21,573 patients treated between January 2013 and December 2017 were analyzed. Outcomes were 90-day mortality, 1-year re-revision rate, and in-house adverse events. The effect of hospital volumes on outcomes were analyzed by means of multivariate logistic regression. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated.

RESULTS

Hospital volume had a significant effect on 1-year re-revision rate (≤12 R-TKA/a: OR 1.44, CI 1.20-1.72; 13-24 R-TKA/a: OR 1.43, CI 1.20-1.71; 25-52 R-TKA/a: OR 1.13, CI 0.94-1.35; ≥53 R-TKA/a: reference). Ninety-day mortality and major in-house adverse events decreased with increasing volume per year, but after risk adjustment this was not statistically significant.

CONCLUSION

We found evidence of higher risk for re-revision surgery in hospitals with fewer than 25 R-TKA per year. It might contribute to improved patient care if complex elective procedures like R-TKA which require experience and a specific logistic background were performed in specialized centers.

Low Hospital Volume Increases Revision Rate and Mortality Following Revision Total Hip Arthroplasty: An Analysis of 17,773 Cases

BACKGROUND

With the number of primary total hip arthroplasty (THA), the amount of revision THA (R-THA) increases. R-THA is a complex procedure requiring special instruments, implants, and surgical skills. Therefore it is likely that hospitals performing a higher number of R-THAs have more experience with this type of surgery and therefore fewer complications. The purpose of this study was to evaluate the relationship between hospital volume and risk of postoperative complications following R-THA.

METHODS

Using nationwide healthcare insurance data for inpatient hospital treatment, 17,773 aseptic R-THAs in 16,376 patients treated between January 2014 and December 2016 were included. Outcomes were 90-day mortality, 1-year revision procedures, and in-house adverse events. The effect of hospital volume on outcome was analyzed by means of multivariate logistic regression. Adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were calculated.

RESULTS

Hospital volume had a significant effect on 90-day mortality (≤12 cases per year: OR 2.13, CI 1.53-2.96; 13-24: OR 1.79, CI 1.29-2.50; 25-52: OR 1.53, CI 1.11-2.10; ≥53: reference) and 1-year revision procedures (≤12: OR 1.26, CI 1.09-1.47; 13-24: OR 1.18, CI 1.02-1.37; 25-52: OR 1.03, CI 0.90-1.19; ≥53: reference). There was no significant effect on risk-adjusted major in-house adverse events.

CONCLUSION

We found evidence of higher risk for revision surgery and mortality in hospitals with fewer than 25 and 53 R-THA per year, respectively. To improve patient care, complex elective procedures like R-THA which require experience and a specific logistic background should be performed in specialized centers.

Revision of Failed Metal-on-Metal Total Hip Arthroplasty: Midterm Outcomes of 203 Consecutive Cases

BACKGROUND

Metal-on-metal (MoM) revisions have shown high rates of complications from aseptic loosening, deep infection, and dislocation. The purpose of this study is to report on outcomes and complications of a large consecutive series of patients who were revised for failed MoM total hip arthroplasty (THA).

METHODS

We evaluated 188 patients (203 hips) who underwent revisions of failed MoM THA. Mean age at the revision was 60 years old. Gender was female in 112 hips (55%) and male in 91 hips (45%). Mean interval to failure after primary THA was 4.9 years (range, 0-18 years). The acetabular component was revised in 183 cases (92%). Clinical outcomes assessed included pain score and Harris hip score.

RESULTS

Mean follow-up from revision was 4.2 years. Harris hip score improved from 53.6 pre-revision to 73.5 at most recent follow-up (P < .001). Pain level significantly improved from 17.2 pre-revision to 32.8 post-revision (P < .001). Reoperations occurred in 28 (14%) hips. Re-revision was required in 16 hips (7.9%). The most common reasons for re-revision were aseptic loosening (5), dislocation (3), infection (2), and iliopsoas tendonitis (2). Re-revision was significantly higher in cases of pseudotumor. There was no difference in survival with ultraporous cups. Three hips required re-revision to custom triflange components. All-cause survival was 90.5% at 4.2 years. Metal ion levels significantly declined after revision.

CONCLUSION

Revisions of failed MoM THA showed improvements in clinical outcomes, but present significant surgical challenges and complications especially in cases with soft tissue damage and pseudotumor.

Total Hip Arthroplasty Performed for Coxarthrosis Preserves Long-Term Physical Function: A 40-Year Experience

BACKGROUND

Measures of long-term success of total hip arthroplasty (THA) over the past 50 years have focused primarily on implant survival, with less evidence on long-term functional outcomes.

QUESTIONS/PURPOSES

We aimed to study 20-to-40-year functional outcomes after primary THA. We investigated the extent to which (1) functional outcomes after THA are maintained long term; (2) patient characteristics such as age, hip disease diagnosis, and comorbidities affect recovery of function and survivorship after THA; and (3) patients' overall function after THA is affected by the need for revision, the aging process, and associated comorbidities.

METHODS

We retrospectively reviewed outcomes of the senior author's patients between 1968 and 1993. Of 1207 patients, we identified 167 patients (99 female, 68 male; 276 primary THAs) who were at least 65 years old at follow-up and had at least 20 years of follow-up. Mean age at surgery was 55 years; mean follow-up time was 27 years. Bilateral THAs were performed in 109 patients (65%), and revisions in 81 patients (48.5%). Clinical outcomes including pain level, walking ability, range of motion, and overall function were determined by the Hospital for Special Surgery (HSS) hip scoring system. Contralateral and revision surgery, as well as patient age, sex, and body mass index, were included as covariates. To account for unequally spaced follow-up time points and competing causes of functional decline (e.g., age, contralateral hip disease, and need for revision THA), a latent class mixed model approach was used to identify unobserved classes of patients who had similar outcomes. Linear, quadratic, and piecewise-polynomial growth models were considered for class identification. The best fitting model was determined based on Bayesian information criterion.

RESULTS

A four-class model of this patient population was identified: (1) the Elderly Class, who had a mean age of 62 years at the time of primary THA; (2) the Bilateral Class, who underwent simultaneous or staged bilateral THA; (3) the Revision Class, who required at least one revision; and (4) the Youngest Class, who had a mean age of 49 years. After an initial period of improvement in all groups, the functional trajectory diverged according to classifications. Age was the strongest determinant of long-term outcome, with HSS hip scores in the Elderly Class declining after about 20 years. The Youngest Class maintained good-to-excellent hip function for over 30 years. Revision THA and contralateral THA accounted for a temporary decline in function, after which overall good function was regained for the long term.

CONCLUSIONS

All classes in the study population enjoyed good-to-excellent outcomes after THA for about 20 years. Thereafter, functional decline was attributed more to aging than to the need for revision. One or more revision THA did not negatively influence long-term clinical outcomes, suggesting that, even for younger patients, symptoms, rather than the avoidance of possible revision, should be the primary determining factor when indicating THA.

Comparative Mid-term Follow-up Study of Primary Total Hip Arthroplasty with Metal-on-metal and Metal-on-polyethylene Bearings

OBJECTIVE

To compare mid-term clinical results of total hip arthroplasty (THA) with metal-on-metal (MoM) and metal-on-polyethylene (MoP) bearings and to evaluate the biological safety of the two kinds of prostheses.

METHODS

Thirty-two patients who received a primary THA with an MoM articulation between January 2008 and December 2010 were selected to form the MoM group retrospectively. The MoP group consisted of 32 patients who received a THA with an MoP prosthesis during the same period. Clinical assessments, imaging examinations, laboratory tests, and metal ion concentration detections were conducted on each patient. Another 32 healthy volunteers were recruited as the control group.

RESULTS

Twenty-seven patients in the MoM group and 28 patients in the MoP group completed the follow-up, with a mean follow-up time of 74.6 and 75.9 months, respectively. The mean Harris score at the latest follow-up was 91.5 ± 5.1 in the MoM group versus 88.9 ± 4.0 in the MoP group (P = 0.22). The MoM group showed a better range of motion in flexion, abduction, and external rotation. Co and Cr levels in the MoM group were 2.5-fold and 2.0-fold of these in the MoP group. A mild change of liver function was observed in both groups, while the values of renal function and humoral immunity stayed static. Elevated proportions of Th1 and Th17 cells and decreased proportion of Th2 cells were observed in the MoM group. The occurrence rate of pseudotumors in the MoM and MoP groups was 40.74% ± 9.45% and 14.28% ± 6.61%, respectively (P < 0.05).

CONCLUSION

At the mid-term follow-up, clinical results were satisfied in both groups. MoM prosthesis could result in elevated serum metal ion levels and there is a higher risk of pseudotumor. Long follow-up is needed to evaluate the safety of MoM prostheses.

Results and Patient Reported Outcome Measures (PROMs) after One-Stage Revision for Periprosthetic Joint Infection of the Hip: A Single-centre Retrospective Study

Background: Little is known about functional outcome and quality of life (QoL) after one-stage revision for periprosthetic joint infection (PJI) of the hip. Methods: a cohort of 30 subjects treated with one-stage revision between 2011 and 2015 was identified, and questionnaires on functional outcome and QoL were distributed. Results: 28 subjects were successfully treated (93%). Most subjects were referred from other hospitals. Coagulase-negative Staphylococcus was found in 50% of the cases, and 40% of all cultured bacteria were multidrug-resistant. 25% had subsequent revision surgery, unrelated to PJI. Functional outcome was good and QoL scores were high, comparable to prosthetic joint revision surgery in general. Conclusion: Although the cohort was small and statistical analysis was not performed, this study showed that excellent results can be obtained with one-stage revision for hip PJI. Functional outcome and QoL was comparable to prosthetic joint revision surgery in general.

Clinical Outcome of Massive Endoprostheses Used for Managing Periprosthetic Joint Infections of the Hip and Knee

BACKGROUND

Endoprosthetic replacement (EPR) is an option for management of massive bone loss resulting from infection around failed lower limb implants. The aim of this study is to determine the mid-term outcome of EPRs performed in the treatment of periprosthetic joint infection (PJI) and infected failed osteosyntheses around the hip and knee joint and identify factors that influence it.

METHODS

We retrospectively reviewed all hip and knee EPRs performed between 2007 and 2014 for the management of chronic infection following complex arthroplasty or fracture fixation. Data recorded included indication for EPR, number of previous surgeries, comorbidities, and organism identified. Outcome measures included PJI eradication rate, complications, implant survival, mortality, and functional outcome (Oxford Hip or Knee Score).

RESULTS

Sixty-nine EPRs (29 knees and 40 hips) were performed with a mean age of 68 years (43-92). Polymicrobial growth was detected in 36% of cases, followed by coagulase-negative staphylococci (28%) and Staphylococcus aureus (10%). Recurrence of infection occurred in 19 patients (28%): 5 were treated with irrigation and debridement, 5 with revision, 1 with above-knee amputation, and 8 remain on long-term antibiotics. PJI eradication was achieved in 50 patients (72%); the chance of PJI eradication was greater in hips (83%) than in knees (59%) (P = .038). The 5-year implant survivorship was 81% (95% confidence interval 74-88). The mean Oxford Hip Score and Oxford Knee Score were 22 (4-39) and 21 (6-43), respectively.

CONCLUSION

This study supports the use of EPRs for eradication of PJI in complex, multiply revised cases. We describe PJI eradication rate of 72% with acceptable functional outcome.

Outcome Following Debridement, Antibiotics, and Implant Retention in Hip Periprosthetic Joint Infection-An 18-Year Experience

BACKGROUND

Debridement-antibiotics-and-implant-retention (DAIR) may be considered a suitable surgical option in periprosthetic joint infections (PJIs) with soundly fixed prostheses, despite chronicity. This study aims to define the long-term outcome following DAIR in hip PJI.

METHODS

We reviewed all hip DAIRs performed between 1997 and 2013 (n = 122) to define long-term outcome and identify factors influencing it. Data recorded included patient demographics, medical history, type of DAIR performed (+/- exchange of modular components), and organisms identified. Outcome measures included complications and/or mortality rate, implant survivorship, and functional outcome (Oxford Hip Score).

RESULTS

Most DAIRs (67%) were of primary arthroplasties and 60% were performed within 6 weeks from the index arthroplasty. Infection eradication was achieved in 68% of the first DAIR procedure. In 32 cases, more than one DAIR was required. Infection eradication was achieved in 85% of the cases (104/122) with the (single or multiple) DAIR approach. The most common complication was PJI-persistence (15%), followed by dislocation (14%). Very good functional outcomes were obtained, especially in primary arthroplasties. All streptococcus infections were resolved with DAIR and had better outcome. Twenty-one hips have been revised (17%) to-date, 16 were for persistence of PJI. The 10-y implant survivorship was 77%. Early PJI and exchanging modular components at DAIR were independent factors for a 4-fold increased infection eradication and improved long-term implant survival.

CONCLUSION

DAIR is, therefore, a valuable option in the treatment of hip PJI, especially in the early postoperative period (≤6 weeks), with good outcomes. However, DAIR is associated with increased morbidity; further surgery may be necessary and instability may occur. Where possible, exchange of modular implants should be undertaken.

Acetabulum-Only Revision Total Hip Arthroplasty Is Associated With Good Functional Outcomes and Survivorship

BACKGROUND

The coexistence of a stable femoral and a loose acetabular component may pose a clinical dilemma for the surgeon. Our study aims at comparing the intermediate functional outcomes and survivorship of acetabulum-only revision total hip arthroplasty (ArTHA) with an age-matched and gender-matched total revision THA (TrTHA) group.

METHODS

We retrospectively reviewed prospectively collected data on the pain, function, and total Harris Hip Scores (HHS) and complication profile for ArTHA and TrTHA cohorts from our regional arthroplasty database. Kaplan-Meier survivorship, with the need for repeat revision surgery as the end point, was used for survival analysis.

RESULTS

Among 538 cases, there were fewer acute medical complications in ArTHA and a similar dislocation rate for both cohorts. Preoperative HHS for pain, function, and total were better in the ArTHA cohort, but only the function score reached statistical significance. No significant differences in subsequent years for all aspects of HHS, except the function score was significantly better in the ArTHA cohort at year 1. And 10.0% of ArTHAs and 7.8% of TrTHAs had required rerevision. The 5-year survivorship was 90.3% (95% confidence interval ± 2.1%) for the ArTHA cohort and 92.7% (95% confidence interval ± 1.8%) for the TrTHA cohort (P = .394). The ArTHA with posterior approach (n = 118) group had the lowest dislocation rate and the best trend of functional outcomes.

CONCLUSION

ArTHA can provide similar functional outcomes and dislocation rate to TrTHA, with an acceptable rerevision rate. The posterior approach in this study was not associated with a significant dislocation rate.

Complications After Revision Total Hip Arthroplasty in the Medicare Population

BACKGROUND

The purpose of this study was to identify the incidence and types of complications after revision total hip arthroplasty (THA) within the first year, and determine the relative risk factors for these complications and of re-revision.

METHODS

The sample size of 5% Medicare claims data from 1998-2011 was studied. Primary THA patients who underwent subsequent revision were identified using ICD-9-CM codes. Outcomes and complications after revision THA were assessed. Multivariate Cox regression was used to evaluate the effect of patient demographic characteristics on the adjusted complication risk for revision THA patients.

RESULTS

Of the 64,260 primary THA patients identified between 1998 and 2011, 3555 patients (5.71%) underwent revision THA. Etiology of primary hip failure included mechanical complications such as loosening and wear (40.7%), dislocation (14.0%), and infection (11.3%). Complications after revision THA included infection and redo revision, 17.3% and 15.8% followed by venous thromboembolic disease (VTE) at 11.1%, dislocation at 5.43%, PE at 3.24%, and death at 2.11%. The rate of "new" infections after an aseptic revision was 8.13%. Patients in the 85+-year-old age group had a 100% greater adjusted risk of VTE (P < .001) and 406% higher adjusted risk of death (P < .001) than those in the 65-69 years-old age group. Patients with higher Charlson scores had higher adjusted risks of VTE (P < .001), infection (P < .001), death (P = .002), and re-revision THA (P = .011).

CONCLUSION

Advanced age is a clear risk factor for VTE and mortality, but not for dislocation, infection, or re-revision. Higher Charlson index was found to be a risk factor for every complication after revision except dislocation. Greater attention is required to address the high rate of infection and re-do revision after revision THA (17.3% and 15.8%).

Poor Survivorship and Frequent Complications at a Median of 10 Years After Metal-on-Metal Hip Resurfacing Revision

BACKGROUND

High short-term failure rates have been reported for several metal-on-metal hip resurfacing (MoMHR) designs. Early observations suggested that MoMHRs revised to total hip arthroplasties (THAs) for pseudotumor had more major complications and inferior patient-reported outcomes compared with other revision indications. However, little is known about implant survivorship and patient-reported outcomes at more than 5 years after MoMHR revision.

QUESTIONS/PURPOSES

(1) What are the implant survivorship, proportion of complications and abnormal radiological findings, and patient-reported outcomes at a median of 10 years after MoMHR revision surgery? (2) Are survivorship, complications, and patient-reported outcomes influenced by revision indication? (3) Do any other factors predict survivorship, complications, and patient-reported outcomes?

METHODS

Between 1999 and 2008, 53 MoMHR revision procedures in 51 patients (mean age, 55 years; 62% female) were performed at one center and were all included in this retrospective study. Two patients (4%) were lost to followup and two patients (4%) died before a minimum followup of 7 years (median, 10.3 years; range 7-15 years). Revision indications included pseudotumor (n = 16), femoral neck fracture (n = 21), and other causes (n = 16). In most cases (62%, n = 33) both components were revised to a non-MoM bearing THA with the remainder (38%, n = 20: fracture, loosening, or head collapse) undergoing femoral-only revision to a large-diameter MoM THA. Postrevision complications, rerevision, Oxford Hip Score (OHS), and UCLA score were determined using both a longitudinally maintained institutional database and postal questionnaire. Implant survivorship was assessed using the Kaplan-Meier method (endpoint was rerevision surgery). Radiographs at latest followup were systematically assessed for any signs of failure (loosening, migration, osteolysis) by one observer blinded to all clinical information and not involved in the revision procedures.

RESULTS

Overall, 45% (24 of 53) experienced complications and 38% (20 of 53) underwent rerevision. Ten-year survival free from rerevision for revised MoMHRs was 63% (95% confidence interval [CI], 48%-74%). Revision indications were not associated with differences in the frequency of complications or repeat revisions. With the numbers available, 10-year survival free from rerevision for pseudotumor revisions (56%; 95% CI, 30%-76%) was not different from the fracture (68%; 95% CI, 42%-85%; p = 0.359) and other groups (63%; 95% CI, 35%-81%; p = 0.478). Pseudotumor revisions had inferior OHSs (median, 21; range, 2-46; p = 0.007) and UCLA scores (median, 2; range, 2-7; p = 0.0184) compared with fracture and other revisions. Ten-year survival free from rerevision after femoral-only revision using another large-diameter MoM bearing was lower (p = 0.0498) compared with all component revisions using non-MoM bearings. After controlling for potential confounding variables such as age, sex, and revision indication, we found femoral-only revision as the only factor predicting rerevision (hazard ratio, 5.7; 95% CI, 1.1-29; p = 0.040).

CONCLUSIONS

Poor implant survivorship and frequent complications were observed at a median of 10 years after MoMHR revision. However, patients undergoing femoral-only revisions with large-diameter MoM bearings had the worst survivorship, whereas patients revised for pseudotumor had the most inferior patient-reported outcomes. Our findings suggest these two patient subgroups require regular surveillance after MoMHR revision.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Five-year outcome of proximal femoral endoprosthetic arthroplasty for non-tumour indications

OBJECTIVES

A possible solution for the management of proximal femoral bone loss is a modular femoral endoprosthesis (EPR). Although the outcome of EPRs in tumour surgery has been well described, the outcome of their use in revision hip surgery has received less attention. The aim of this study was to describe the outcome of using EPR for non-neoplastic indications.

METHODS

A retrospective review of 79 patients who underwent 80 EPRs for non-neoplastic indications was performed, including the rates of complication and survival and the mean Oxford Hip Scores (OHS), at a mean of five years post-operatively. The mean age at the time of surgery was 69 years (28 to 93) and the mean number of previous operations on the hip was 2.4 (0 to 17). The most common indications for EPR implantation were periprosthetic joint infection (PJI) (n = 40), periprosthetic fracture (n = 12) and failed osteosynthesis of a proximal femoral fracture or complex trauma (n = 11).

RESULTS

Salvage was achieved in all patients. A total of 25 patients (25 EPRs, 31.6%) had a complication, the most common being infection (n = 9) and dislocation (n = 3). Further surgery was required for 18 EPRs (22%), nine of which were revision procedures. The five year survival of the EPR was 87% (95%CI: 76% to 98%). The mean OHS was 28 (4 to 48). Inferior survival and outcomes were seen in EPRs which were performed for the treatment of infection. However, the eradication of infection was achieved in 33 of the 40 (82.5%) which were undertaken for this indication.

CONCLUSION

We recommend the continued use of proximal femoral EPRs for non-neoplastic indications, including PJI. Cite this article: Bone Joint J 2016;98-B:1463-70.

Adverse reactions to metal debris occur with all types of hip replacement not just metal-on-metal hips: a retrospective observational study of 3340 revisions for adverse reactions to metal debris from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

BACKGROUND

Adverse reactions to metal debris (ARMD) have resulted in the high short-term failure rates observed with metal-on-metal hip replacements. ARMD has recently been reported in non-metal-on-metal total hip replacements (non-MoM THRs) in a number of small cohort studies. However the true magnitude of this complication in non-MoM THRs remains unknown. We used a nationwide database to determine the risk of ARMD revision in all non-MoM THRs, and compared patient and surgical factors associated with ARMD revision between non-MoM and MoM hips.

METHODS

We performed a retrospective observational study using data from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. All primary hip replacements undergoing revision surgery for ARMD were included (n = 3,340). ARMD revision risk in non-MoM THRs was compared between different commonly implanted bearing surfaces and femoral head sizes (Chi-squared test). Differences in patient and surgical factors between non-MoM hips and MoM hips revised for ARMD were also analysed (Chi-squared test and unpaired t-test).

RESULTS

Of all ARMD revisions, 7.5% (n = 249) had non-MoM bearing surfaces. The relative risk of ARMD revision was 2.35 times (95% CI 1.76-3.11) higher in ceramic-on-ceramic bearings compared with hard-on-soft bearings (0.055 vs. 0.024%; p < 0.001), and 2.80 times (95% CI 1.74-4.36) higher in 36 mm metal-on-polyethylene bearings compared to 28 mm and 32 mm metal-on-polyethylene bearings (0.058 vs. 0.021%; p < 0.001). ARMD revisions were performed earlier in non-MoM hips compared to MoM hips (mean 3.6-years vs. 5.6-years; p < 0.0001). Non-MoM hips had more abnormal findings at revision (63.1 vs. 35.7%; p < 0.001), and more intra-operative adverse events (6.4 vs. 1.6%; p < 0.001) compared to MoM hips.

CONCLUSIONS

Although the overall risk of ARMD revision surgery in non-MoM THRs appears low, this risk is increasing, and is significantly higher in ceramic-on-ceramic THRs and 36 mm metal-on-polyethylene THRs. ARMD may therefore represent a significant clinical problem in non-MoM THRs.

The Diagnosis of Infection in Metal-on-Metal Hip Arthroplasties

BACKGROUND

Distinction of aseptic from septic hip arthroplasty failure can be challenging. Some studies report an increased incidence of septic failure with metal-on-metal (MoM) hip arthroplasties. The Musculoskeletal Infection Society (MSIS) have formulated criteria to facilitate the diagnosis of periprosthetic joint infection (PJI). In this study, we determined the prevalence and histologic features of septic MoM hip failure.

METHODS

Overall, 104 cases of failed MoM hip arthroplasty, classified as septic or aseptic by MSIS microbiological criteria, were analyzed. The overall prevalence of septic failure was determined and the nature of the causative organisms noted. The extent of the neutrophil polymorph (NP) infiltrate in periprosthetic tissue in all cases was analyzed by hematoxylin-eosin and chloroacetate esterase staining.

RESULTS

The prevalence of septic MoM hip arthroplasty failure was 6.7%. Infective organisms were coagulase-negative Staphylococcus in 4 cases; Staphylococcus aureus, Streptococcus, and Propionibacterium species were isolated in the remaining cases. Chloroacetate esterase staining facilitated identification of NPs. All cases of PJI contained more than 5 NPs per high-power field (HPF) on average. Four cases of aseptic MoM implant failure contained scanty or scattered NPs (less than 5 per HPF on average).

CONCLUSION

The prevalence of PJI as a cause of MoM hip arthroplasty failure was relatively high compared to other hip bearing combinations; however, the organisms responsible were similar. Histologically, a minority of aseptic MoM implant failures contained some NPs, but the MSIS criteria for the histologic diagnosis of PJI (>5 NPs/HPF) correctly identified all microbiologically confirmed cases of septic failure.

Prevalence of and Risk Factors for Hip Resurfacing Revision: A Cohort Study Into the Second Decade After the Operation

BACKGROUND

Most metal-on-metal hip resurfacing (MoMHR) designs have experienced high short-term failure rates because of pseudotumors. The impact of this complication into the second decade after the procedure is unknown. We investigated (1) the prevalence of, and risk factors for, all-cause and pseudotumor-related revision at up to 15 years following MoMHR and (2) whether risk factors were sex-specific.

METHODS

This single-center prospective cohort study included 1,429 MoMHRs (1216 patients; 40% female) implanted between 1999 and 2009. Patients were contacted in 2010 and 2012 as per national recommendations. Patients with symptoms related to the hip and/or suboptimal Oxford Hip Scores (≤41 of 48 points) underwent cross-sectional imaging and blood metal-ion sampling. Revision diagnoses were established using operative and histopathological findings. Multivariate Cox proportional hazard models were used to assess the association of predictor variables with the time to all-cause and pseudotumor-related revisions.

RESULTS

One hundred and eighty MoMHRs (12.6%) were revised for all causes, and 111 (7.8% of the series and 61.7 % of all revisions) were revised because of pseudotumor. Survival analysis showed the 15-year cumulative revision rate for all causes to be 19.5% (95% confidence interval [CI] = 16.2% to 23.2%) and the 15-year rate of revision due to pseudotumor to be 14.0% (95% CI = 11.0% to 17.7%). Small femoral head size (hazard ratio [HR] per 2 mm = 0.92, 95% CI = 0.88 to 0.97; p = 0.003) and certain implant designs (HR = 1.55 to 3.01; p ≤ 0.029) significantly increased the all-cause revision risk. Female sex (HR = 2.03, 95% CI = 1.19 to 3.44; p = 0.009) and young age (HR per year = 0.98, 95% CI = 0.96 to 1.00; p = 0.020) significantly increased the pseudotumor-related revision risk but not the all-cause revision risk. Risk factors for all-cause and pseudotumor-related revision were sex-specific. In females, small femoral head size (p = 0.014) increased the all-cause revision risk, and young age was the only predictor of pseudotumor-related revision (p = 0.019). In males, implant design was the only predictor of all-cause revision (p ≤ 0.015) and pseudotumor-related revision (p = 0.001).

CONCLUSIONS

The prevalence and rates of revision for all causes and pseudotumor were high at up to 15 years following MoMHR. Predictors of revision differed between all-cause and pseudotumor-related revisions and were sex-specific. These factors must be appropriately weighted when risk-stratifying patients with MoMHRs for surveillance.

LEVEL OF EVIDENCE

Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Medial unicompartmental knee arthroplasty in the ACL-deficient knee

Symptomatic osteoarthritis (OA) of the knee develops often in association with anterior cruciate ligament (ACL) deficiency. Two distinct pathologies should be recognised while considering treatment options in patients with end-stage medial compartment OA and ACL deficiency. Patients with primary ACL deficiency (usually traumatic ACL rupture) can develop secondary OA (typically presenting with symptoms of instability and pain) and these patients are typically young and active. Patients with primary end stage medial compartment OA can develop secondary ACL deficiency (usually degenerate ACL rupture) and these patients tend to be older. Treatment options in either of these patient groups include arthroscopic debridement, reconstruction of the ACL, high tibial osteotomy (HTO) with or without ACL reconstruction, unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). General opinion is that a functionally intact ACL is a fundamental prerequisite to perform a UKA. This is because previous reports showed higher failure rates when ACL was deficient, probably secondary to wear and tibial loosening. Nevertheless in some cases of ACL deficiency with end-stage medial compartment OA, UKA has been performed in isolation and recent papers confirm good short- to mid-term outcome without increased risk of implant failure. Shorter hospital stay, fewer blood transfusions, faster recovery and significantly lower risk of developing major complications like death, myocardial infarction, stroke, deep vein thrombosis (as compared to TKA) make the UKA an attractive option, especially in the older patients. On the other hand, younger patients with higher functional demands are likely to benefit from a simultaneous or staged ACL reconstruction in addition to UKA to regain knee stability. These procedures tend to be technically demanding. The main aim of this review was to provide a synopsis of the existing literature and outline an evidence-based treatment algorithm.

Multi-disciplinary antimicrobial strategies for improving orthopaedic implants to prevent prosthetic joint infections in hip and knee

Like any foreign object, orthopaedic implants are susceptible to infection when introduced into the human body. Without additional preventative measures, the absolute number of annual prosthetic joint infections will continue to rise, and may exceed the capacity of health care systems in the near future. Bacteria are difficult to eradicate from synovial joints due to their exceptionally diverse taxonomy, complex mechanistic attachment capabilities, and tendency to evolve antibiotic resistance. When a primary orthopaedic implant fails from prosthetic joint infection, surgeons are generally challenged by limited options for intervention. In this review, we highlight the etiology and taxonomic groupings of bacteria known to cause prosthetic joint infections, and examine their key mechanisms of attachment. We propose that antimicrobial strategies should focus on the most harmful bacteria taxa within the context of occurrence, taxonomic diversity, adhesion mechanisms, and implant design. Patient-specific identification of organisms that cause prosthetic joint infections will permit assessment of their biological vulnerabilities. The latter can be targeted using a range of antimicrobial techniques that exploit different colonization mechanisms including implant surface attachment, biofilm formation, and/or hematogenous recruitment. We anticipate that customized strategies for each patient, joint, and prosthetic component will be most effective at reducing prosthetic joint infections, including those caused by antibiotic-resistant and polymicrobial bacteria.

Instrumented hip joint replacements, femoral replacements and femoral fracture stabilizers

This paper reviews instrumented hip joint replacements, instrumented femoral replacements and instrumented femoral fracture stabilizers. Examination of the evolution of such implants was carried out, including the detailed analysis of 16 architectures, designed by 8 research teams and implanted in 32 patients. Their power supply, measurement, communication, processing and actuation systems were reviewed, as were the tests carried out to evaluate their performance and safety. These instrumented implants were only designed to measure biomechanical and thermodynamic quantities in vivo, in order to use such data to conduct research projects and optimize rehabilitation processes. The most promising trend is to minimize aseptic loosening and/or infection following hip or femoral replacements or femoral stabilization procedures by using therapeutic actuators inside instrumented implants to apply controlled stimuli in the bone-implant interface.

Revision THA in obese patients is associated with high re-operation rates at short-term follow-up

We performed a retrospective review of 309 consecutive revision THAs from 2005 to 2009. We identified a subgroup of patients with BMI >35 and compared the operative time, rate of complications, ICU admissions, re-admissions, and re-operations to patients with BMI <35 undergoing revision THA. At a mean follow-up of 36.3 months, there was no significant difference in operative time, perioperative complications, or re-admission rate between the two groups. However, a significantly higher rate of re-operation was observed in the obese group (46% vs. 28%, P=0.015). Obese patients were more likely to undergo reoperation for infection (P=0.017). Patients with high BMI contemplating primary THA should be aware of the potential subsequent complications associated with revision surgery should it become necessary.