Patient-related risk factors for early revision of total hip replacements. A population register-based case-control study of 674 revised hips

Patient-Reported Outcome Measures in High-Risk Medical Device Registries: A Scoping Review

Little is known about the methods and outcomes of patient-reported outcome measure (PROM) use among high-risk medical device registries. The objective of this scoping review was to assess the utility and predictive ability of PROMs in high-risk medical device registries. We searched Ovid Medline, Embase, APA PsychINFO, Cochrane Library, and Scopus databases for published literature. After searching, 4323 titles and abstracts were screened, and 262 full texts were assessed for their eligibility. Seventy-six papers from across orthopedic (n = 64), cardiac (n = 10), penile (n = 1), and hernia mesh (n = 1) device registries were identified. Studies predominantly used PROMs as an outcome measure when comparing cohorts or surgical approaches (n = 45) or to compare time points (n = 13) including pre- and postintervention. Fifteen papers considered the predictive ability of PROMs. Of these, 8 treated PROMs as an outcome, 5 treated PROMs as a risk factor through regression analysis, and 2 papers treated PROMs as both a risk factor and as an outcome. One paper described PROMs to study implant survival. To advance methods of PROM integration into clinical decision-making for medical devices, an understanding of their use in high-risk device registries is needed. This scoping review found that there is a paucity of studies using PROMs to predict long-term patient and clinical outcomes in high-risk medical device registries. Determination as to why PROMs are rarely used for predictive purposes in long-term data collection is needed if PROM data are to be considered suitable as real-world evidence for high-risk device regulatory purposes, as well as to support clinical decision-making.

Level of Evidence 4

Revision hip arthroplasty dislocation risk calculator: when to select dual mobility, large heads, constrained liners, or a standard head size? Testing one hundred thousand hip revisions with artificial intelligence

PURPOSE

Preventing dislocation with large head (≥ 36 mm), dual mobility, or constrained acetabular liner is another option than a standard (≤ 32 mm). Many other dislocations risk factors than size of the femoral head exist after hip arthroplasty revision. Predicting dislocation with a calculator according to the implant, to the indication of revision, and to patient's risks could allow a better surgery decision.

METHODS

Our search method covers the period from 2000 to 2022. A total of 470 relevant citations on hip major revision (cup or stem or both revisions) were identified with artificial intelligence comprising 235 publications of 54,742 standard heads comprising 142 publications of 35,270 large heads, comprising 41 publications of 3945 constrained acetabular components, and 52 publications of 10,424 dual mobility implants. We considered four implant types (standard, large head, dual mobility, or constrained acetabular liner) as the entry layer of the artificial neural network (ANN). Indication for revision THA was the second hidden layer. Demographics, spine surgery, and neurologic disease were the third layer. Implant revision, reconstruction process as next input (hidden layer). Surgery-related factors, and so on. The output was a postoperative dislocation or not.

RESULTS

Of the 104,381 hips that underwent a major revision, a second revision for dislocation was performed for 9234 hips. In each implant group, dislocation remained the first cause of revision. The rate of second revision for dislocation as a percentage of first revision procedures was significantly higher in the standard head group (11.8%) than in the constrained acetabular liner group (4.5%), the dual mobility group (4.1%), and the large head group (6.1%). Instability of a previous THA, infection, or periprosthetic fracture as the indication for revision was increased risk factors as compared with aseptic loosening. One hundred variables were used to create the calculator with the best parameter combination of data and ranking the different factors, according to the four implant types (standard, large head, dual mobility, or constrained acetabular liner).

CONCLUSION

The calculator can be used as a tool to identify patients at risk for dislocation after hip arthroplasty revision and individualize recommendations to select another option than a standard head size.

Disparities in Elective and Nonelective Total Hip Arthroplasty

BACKGROUND

Prior studies have shown disparities in utilization of primary and revision total hip arthroplasty (THA). However, little is known about patient population differences associated with elective and nonelective surgery. Therefore, the aim of this study was to explore factors that influence primary utilization and revision risk of THA based on surgery indication.

METHODS

Data were obtained from 7,543 patients who had a primary THA from 2014 to 2020 in a database, which consists of multiple health partner systems in Louisiana and Texas. Of these patients, 602 patients (8%) underwent nonelective THA. THA was classified as "elective" or "nonelective" if the patient had a diagnosis of hip osteoarthritis or femoral neck fracture, respectively.

RESULTS

After multivariable logistic regression, nonelective THA was associated with alcohol dependence, lower body mass index (BMI), women, and increased age and number of comorbid conditions. No racial or ethnic differences were observed for the utilization of primary THA. Of the 262 patients who underwent revision surgery, patients who underwent THA for nonelective etiologies had an increased odds of revision within 3 years of primary THA (odds ratio (OR) = 1.66, 95% Confidence Interval (CI) = 1.06-2.58, P-value = .025). After multivariable logistic regression, patients who had tobacco usage (adjusted odds ratio (aOR) = 1.36, 95% CI = 1.04-1.78, P-value = .024), alcohol dependence (aOR = 2.46, 95% CI = 1.45-4.15, P-value = .001), and public insurance (OR = 2.08, 95% CI = 1.18-3.70, P-value = .026) had an increased risk of reoperation.

CONCLUSION

Demographic and social factors impact the utilization of elective and nonelective primary THA and subsequent revision surgery. Orthopaedic surgeons should focus on preoperative counseling for tobacco and alcohol cessation as these are modifiable risk factors to directly decrease reoperation risk.

Risk of total hip arthroplasty after elite sport: linking 3304 former world-class athletes with the Norwegian Arthroplasty Register

OBJECTIVES

At present, there is no cure for osteoarthritis (OA), but severe hip joint degeneration can require total hip arthroplasty (THA). The literature on OA after elite sport is limited. We hypothesise that elite athletic activity increases the risk of receiving a THA later in life.

METHODS

We linked a cohort of former Norwegian world-class athletes (1402 females and 1902 males, active 1936-2006) to the Norwegian Arthroplasty Register (THA performed 1987-2020). We used standardised incidence ratio (SIR), one-minus Kaplan-Meier and relative Cox regression (relative HR, RHR), with 95% CIs, and funnel plots at age 75, to assess THA risk for different sport disciplines, joint impact categories of sport disciplines and sex. The risk of THA for the corresponding general Norwegian population was used as reference.

RESULTS

We found an overall increased risk for THA for the former elite athletes (SIR 2.11, 95% CI 1.82 to 2.40) at age 75 years, compared with the general population. THA risk at age 75 years was 11.6% for female athletes and 8.3% for male athletes. SIR was 1.90 (95% CI 1.49 to 2.31) for female and 2.28 (95% CI 1.87 to 2.70) for male athletes. Among males, high joint impact sport disciplines were associated with increased risk compared with low-impact sport disciplines (RHR 1.81, 95% CI 1.06 to 3.08, p=0.029).

CONCLUSION

Having been an elite athlete was associated with a doubling of THA risk compared with the general population for both sexes. High joint impact sport disciplines were associated with subsequent THA for male athletes.

Prediction model for an early revision for dislocation after primary total hip arthroplasty

Dislocation is one of the most common complications after primary total hip arthroplasty (THA). Several patient-related risk factors for dislocation have been reported in the previous literature, but only few prediction models for dislocation have been made. Our aim was to build a prediction model for an early (within the first 2 years) revision for dislocation after primary THA using two different statistical methods. The study data constituted of 37 pre- or perioperative variables and postoperative follow-up data of 16 454 primary THAs performed at our institution in 2008–2021. Model I was a traditional logistic regression model and Model II was based on the elastic net method that utilizes machine learning. The models’ overall performance was measured using the pseudo R² values. The discrimination of the models was measured using C-index in Model I and Area Under the Curve (AUC) in Model II. Calibration curves were made for both models. At 2 years postoperatively, 95 hips (0.6% prevalence) had been revised for dislocation. The pseudo R² values were 0.04 in Model I and 0.02 in Model II indicating low predictive capability in both models. The C-index in Model I was 0.67 and the AUC in Model II was 0.73 indicating modest discrimination. The prediction of an early revision for dislocation after primary THA is difficult even in a large cohort of patients with detailed data available because of the reasonably low prevalence and multifactorial nature of dislocation. Therefore, the risk of dislocation should be kept in mind in every primary THA, whether the patient has predisposing factors for dislocation or not. Further, when conducting a prediction model, sophisticated methods that utilize machine learning may not necessarily offer significant advantage over traditional statistical methods in clinical setup.

Risk of revision arthroplasty surgery after exposure to physically demanding occupational or leisure activities: A systematic review

INTRODUCTION

Lower limb arthroplasty is successful at relieving symptoms associated with joint failure. However, physically-demanding activities can cause primary osteoarthritis and accordingly such exposure post-operatively might increase the risk of prosthetic failure. Therefore, we systematically reviewed the literature to investigate whether there was any evidence of increased risk of revision arthroplasty after exposure to intensive, physically-demanding activities at work or during leisure-time.

METHODS

We searched Medline, Embase and Scopus databases (1985-July 2021) for original studies including primary lower limb arthroplasty recipients that gathered information on physically-demanding occupational and/or leisure activities and rates of revision arthroplasty. Methodological assessment was performed independently by two assessors using SIGN, AQUILA and STROBE. The protocol was registered in PROSPERO [CRD42017067728].

RESULTS

Thirteen eligible studies were identified: 9 (4,432 participants) after hip arthroplasty and 4 (7,137participants) after knee arthroplasty. Narrative synthesis was performed due to considerable heterogeneity in quantifying exposures. We found limited evidence that post-operative activities (work or leisure) did not increase the risk of knee revision and could even be protective. We found insufficient high-quality evidence to indicate that exposure to physically-demanding occupations increased the risk of hip revision although "heavy work", agricultural work and, in women, health services work, may be implicated. We found conflicting evidence about risk of revision hip arthroplasty associated with either leisure-time or total physical activities (occupational or leisure-time).

CONCLUSION

There is currently a limited evidence base to address this important question. There is weak evidence that the risk of revision hip arthroplasty may be increased by exposure to physically-demanding occupational activities but insufficient evidence about the impact on knee revision and about exposure to leisure-time activities after both procedures. More evidence is urgently needed to advise lower limb arthroplasty recipients, particularly people expecting to return to jobs in some sectors (e.g., construction, agriculture, military).

Smoking as a Risk Factor for Complications Following Total Joint Arthroplasty

Prior studies evaluating perioperative risk associated with smoking following total joint arthroplasty (TJA) have assessed smoking as a categorical variable. The purpose of this study was to analyze smoking as a risk factor for complications following TJA by assessing pack-year data as a continuous variable. The National Surgical Quality Improvement Program (NSQIP) database was used to identify primary total hip (THA) and total knee arthroplasty (TKA) patients. Propensity scoring was used to match smokers with nonsmokers based on age and sex. Pack-year data were treated as a continuous variable using a smoothing cubic spline analysis to assess risk of wound complications, thrombotic events, 30-day readmission, and total complications. A total of 1044 smokers who underwent a primary TJA were matched to 1044 controls from 143,641 nonsmokers. Smoothing spline analysis did not identify a relationship between increasing pack-years and wound complications, thrombotic events, or total complications. However, the 30-day readmission rate was increased regardless of the pack-year exposure (odds ratio, 2.30; 95% CI, 1.45-3.65; P<.001). This risk persisted after controlling for differences in comorbidities (odds ratio, 2.18; 95% CI, 1.34-3.53; P<.001). Smokers who undergo a TJA procedure have an increased risk of 30-day readmission and wound complications regardless of their pack-year exposure. [Orthopedics. 2021;44(5):e639-e644.].

Osteonecrosis of the hip: is there a difference in the survivorship of total hip arthroplasty with or without previous vascular iliac bone grafting?

Background

Osteonecrosis of the femoral head (ONFH) is a debilitating condition. Vascularized iliac bone graft (VIBG) is a joint-preserving surgery to improve blood supply to the avascular portion of the femoral head which may delay secondary osteoarthritis and total hip arthroplasty (THA). However, whether VIBG will affect the subsequent THA survivorship and outcomes are still uncertain.

Methods

Implant survivorship and clinical outcomes were compared between 27 patients who had undergone prior VIBG and 242 patients who had only undergone THA for ONFH. Baseline characteristics and the postoperative Harris Hip Score (HHS) were also recorded and compared between the two groups. Implant survivorship was determined using Kaplan-Meier survival analysis.

Results

The overall implant survival for all patients who had a primary diagnosis of ONFH and eventually underwent THA was 92.9%. There was no significant difference in the implant survivorship between the group who directly received THA (survivorship of 93%) and the group which failed VIBG and was subsequently converted to THA (survivorship of 91.9%) (p = 0.71). In addition, higher THA revision rates were associated with smokers and drinkers.

Conclusions

VIBG may be a reasonable option as a “buy-time” procedure for ONFH. Even if conversion to THA is eventually required, patients may be reassured that the overall survivorship and clinical outcomes may not be compromised. Patients are recommended to give up smoking and binge drinking prior to THA to increase implant survival rate.

Systematic Review and Meta-Analysis of Tobacco Use as a Risk Factor for Prosthetic Joint Infection After Total Hip Replacement

Background

A prosthetic joint infection (PJI) is one of the possible complications after total hip arthroplasty (THA). Several studies, but not all, have reported smoking as a risk factor of PJIs in orthopaedic surgery. This study summarizes the most recent evidence using a systematic review of whether tobacco use (not only tobacco smoking) is a risk factor in developing PJIs, specifically after THA.

Methods

Ovid Medline, EMBASE, Scopus, Web of Science, and Cochrane databases were searched from inception to July 2019 to identify case-control studies that examined the PJI risk in tobacco users and tobacco nonusers undergoing THA. Publication bias was also assessed through funnel plots.

Results

Searches identified 2689 articles, and 10 of these, involving a total of 20,640 patients, met the inclusion criteria. The overall odds ratio (pooled odds ratio) to develop either a superficial infection, a deep infection, or an infection requiring revision surgery for tobacco users vs nonusers was 1.54 (95% confidence interval: 1.25-1.91) when a fixed-effect model was used and 1.56 (95% confidence interval: 1.10-2.21) when a random-effect model was used. No publication bias was observed among the identified studies.

Conclusions

The findings of the study indicated that tobacco use is associated with a higher risk of PJIs in patients undergoing THA.

Clinical outcomes in elective total hip arthroplasty in Parkinson's disease: a systematic review of the literature

Parkinson’s disease (PD) poses a significant challenge for the arthroplasty surgeon, owing to excessive muscle tone, higher fracture risk and poor bone quality. Several studies have reported high mortality, early failure and perioperative complications associated with hip fracture surgery in PD; however, no higher-level evidence exists regarding elective hip arthroplasty.

The aim of our study was to perform a systematic review to evaluate the evidence basis and clinical outcomes pertaining to patients with underlying Parkinson’s disease undergoing elective total hip arthroplasty (THA).

We searched MEDLINE, EMBASE and The Cochrane Central Register of Controlled Trials to identify studies evaluating the safety and clinical outcomes of THA in patients suffering from Parkinson’s. Our review conforms to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Ten studies encompassing 49,730 patients were included in our systematic review. Qualitative synthesis demonstrated comparable results between PD patients and controls with respect to one-year mortality and surgical site infections. PD patients experienced more medical complications, had a longer hospital stay and worse long-term implant survival. Some studies also reported a higher rate of dislocation, periprosthetic fractures and aseptic loosening.

Decisions about the optimal articulation, the utilization of cemented components, dual-mobility cups or constrained liners were not uniform among included studies.

THA in patients with Parkinson’s disease can offer significant functional gains and pain relief. Surgical considerations pertain to the approach and ways to address instability, whereas emphasis should be placed on appropriate counselling and exploring whether potential improvement of life quality outweighs the risks.

Cite this article: EFORT Open Rev 2020;5:856-865. DOI: 10.1302/2058-5241.5.200034

Increased risk for dislocation after introduction of the Continuum cup system: lessons learnt from a cohort of 1,381 THRs after 1-year follow-up

Background and purpose - The introduction of new total hip replacements (THRs) is known to be associated with an increased risk for complications. On completion of a competitive procurement process, a new uncemented cup system was introduced into general use at our institution in 2016. We launched this study after the introduction to assess (1) the incidence of early dislocations of the old (Pinnacle) and the new (Continuum) cup systems, and (2) whether the cup design would affect the risk for dislocation.Patients and methods - We assessed the incidence of dislocations after 1,381 primary THRs performed at our institution during 2016. Also, the effect of the cup system (Pinnacle, Continuum with neutral liner, Continuum with elevated rim liner) on dislocation rates was analyzed using a multivariable regression model.Results - 47 (3.4%) early dislocations were identified. The incidence of dislocations was 1.3% for the Pinnacle, 5.1% for the Continuum with neutral liner, and 1.2% for the Continuum with elevated rim liner. The Continuum with neutral liner was found to have an increased risk for dislocations compared with the Pinnacle (aOR 5, 95% CI 1.4-17). However, when an elevated rim liner was used with the Continuum, the risk for dislocation between the Continuum and the Pinnacle was similar.Interpretation - Our results emphasize the need for both careful consideration before the introduction of new implants and the systematic monitoring of early outcomes thereafter. The elevated rim liner should be preferred for use with the Continuum cup because of the poor coverage of the neutral liner that may result in dislocations.

The impact of BMI and smoking on risk of revision following knee and hip replacement surgery: evidence from routinely collected data

OBJECTIVE

The aim of this study was to assess the association of body mass index (BMI) and smoking with risk of revision following total knee replacement (TKR) and total hip replacement (THR).

DESIGN

Primary care data, from the Clinical Practice Research Datalink (CPRD), was linked to inpatient hospital records, from Hospital Episode Statistics Admitted Patient Care (HES APC), and covered 1997 to 2014. Parametric survival models, with BMI and smoking status included as explanatory variables, were estimated for 10-year risk of revision and mortality, and were extrapolated to estimate lifetime risk of revision.

FINDINGS

TKR and THR cohorts included 10,260 and 10,961 individuals, respectively. For a change in BMI from 25 to 35, the 10-year risk of revision is expected change from 4.6% (3.3-6.4%) to 3.7% (2.6-5.1%) for TKR and 3.7% (2.8-5.1%) to 4.0% (2.8-5.7%) for THR for an otherwise average patient profile. Meanwhile, changing from a non-smoker to a current smoker is expected to change the risk of revision from 4.1% (3.1-5.5%) to 2.8% (1.7-4.7%) for TKR and from 3.8% (2.8-5.3%) to 2.9% (1.9-4.7%) for THR for an otherwise average patient profile. Estimates of lifetime risk were also similar for different values of BMI or smoking status.

CONCLUSIONS

Obesity and smoking do not appear to have a meaningful impact on the risk of revision following TKR and THR.

Tobacco use predicts a more difficult episode of care after anatomic total shoulder arthroplasty

BACKGROUND

In the current health care environment, it is becoming increasingly important to recognize risks factors that may affect a patient's postoperative outcome. To determine the potential impact of tobacco as a risk factor, we evaluated postoperative pain, narcotic use, length of stay, reoperations, and complications in the global 90-day episode of care for patients undergoing anatomic total shoulder arthroplasty (TSA) who were current tobacco users, former users, or nonusers.

METHODS

Database search identified 163 patients with primary anatomic TSA done for glenohumeral arthritis; these were divided into 3 groups: current tobacco users (28), nonusers (88), and former users (47). All surgeries were done with the same technique and implants.

RESULTS

Patients in the current tobacco use group had significantly higher visual analog scale scores preoperatively and at 12 weeks postoperatively than nonusers and former users. Mean improvement in visual analog scale scores was significantly less in current tobacco users. Cumulative oral morphine equivalent use at 12 weeks was significantly higher in current tobacco users than in nonusers and former users. The average oral morphine equivalent per day was also significantly higher in the current tobacco users than in nonusers and former users. There were no significant differences in length of stay or complications.

CONCLUSIONS

Although length of stay, complication rates, hospital readmissions, and reoperation rates were not significantly different, tobacco users reported increased postoperative pain and narcotic use in the global period after TSA. Former tobacco users were found to have a postoperative course similar to that of nonusers, suggesting that discontinuation of tobacco use can improve a patient's episode of care performance after TSA.

The History of Biomechanics in Total Hip Arthroplasty

Biomechanics of the hip joint describes how the complex combination of osseous, ligamentous, and muscular structures transfers the weight of the body from the axial skeleton into the appendicular skeleton of the lower limbs. Throughout history, several biomechanical studies based on theoretical mathematics, in vitro, in vivo as well as in silico models have been successfully performed. The insights gained from these studies have improved our understanding of the development of mechanical hip pathologies such as osteoarthritis, hip fractures, and developmental dysplasia of the hip. The main treatment of end-stage degeneration of the hip is total hip arthroplasty (THA). The increasing number of patients undergoing this surgical procedure, as well as their demand for more than just pain relief and leading an active lifestyle, has challenged surgeons and implant manufacturers to deliver higher function as well as longevity with the prosthesis. The science of biomechanics has played and will continue to play a crucial and integral role in achieving these goals. The aim of this article, therefore, is to present to the readers the key concepts in biomechanics of the hip and their application to THA.

Smoking Increases the Rate of Reoperation for Infection within 90 Days After Primary Total Joint Arthroplasty

BACKGROUND

The relationship between smoking and complications after total joint arthroplasty is unclear. Prior studies have been limited by relatively small sample sizes or investigation of select cohorts. The purpose of this study was to investigate the association between smoking and readmission and/or reoperation within 90 days of total joint arthroplasty in a large, non-select cohort of patients.

METHODS

Using our institutional database, we retrospectively identified patients who underwent primary total joint arthroplasty between 2000 and 2014. Patients were stratified into 1 of 3 groups: current smokers, former smokers, and nonsmokers. The association between smoking status and subsequent readmission and/or reoperation within 90 days was investigated using multivariate regression analysis.

RESULTS

We retrospectively identified 15,264 patients (6,749 male and 8,515 female) who underwent 17,394 total joint arthroplasties during the study period. Of these patients, 1,371 (9.0%) were current smokers, 5,195 (34.0%) were former smokers, and 8,698 (57.0%) were nonsmokers. Former smokers reported a median of 22.2 years (range, 0.2 to 60 years) of abstinence prior to the surgical procedure. Current smokers were significantly younger (p < 0.001) at a mean age (and standard deviation) of 57.7 ± 10.3 years than nonsmokers at 63.2 ± 11.8 years. Current smokers were significantly more likely than nonsmokers to undergo reoperation for infection (odds ratio [OR], 1.82 [95% confidence interval (CI), 1.03 to 3.23]; p = 0.04), and former smokers were at no increased risk (OR, 1.11 [95% CI, 0.73 to 1.69]; p = 0.61). Packs per decade were independently associated with an increased risk of 90-day nonoperative readmission regardless of smoking status (OR, 1.12 [95% CI, 1.03 to 1.20]). Lastly, neither smoking status nor packs per decade were associated with aseptic or total reoperations.

CONCLUSIONS

This study, after controlling for confounding factors, demonstrated not only that current smokers have a significantly increased risk of reoperation for infection within 90 days of a surgical procedure compared with nonsmokers, but also that the amount that one has smoked, regardless of current smoking status, significantly contributed to increased risk of nonoperative readmission.

LEVEL OF EVIDENCE

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

[Predictive factors of aseptic loosening of cemented total hip prostheses]

Introduction

Le descellement aseptique constitue la principale complication à long terme et signe la faillite de la prothèse totale de hanche. Les causes de descellement aseptique sont multiples et souvent intriquées. Le mal positionnement des implants reste le facteur le plus incriminé. D’autres facteurs liés au patient et à la prothèse prédisposent également au descellement mais à des degrés divers.

Méthodes

A travers une étude rétrospective portant sur 64 descellements aseptiques de prothèse totale de hanche, nous avons tenté d’individualiser les facteurs de descellement lié au patient, au type d’implant et à la technique chirurgicale et d’en dégager les recommandations visant à minimiser ce risque. Il s’agissait d’une étude rétrospective analytique portant sur 64 descellements aseptiques. La classification utilisée est celle de la Société Française de Chirurgie Orthopédique et Traumatologique.

Résultats

La moyenne d’âge au moment de la première arthroplastie était de 40 ans. Elle était de 62 au moment du descellement. La tige type Charnley a été implantée dans 55 cas, celle de type Muller dans 9 cas. La pièce cotyloïdienne a été bien positionnée dans 69% des cas avec une inclinaison moyenne de 47,8°. Les tiges étaient remplissantes dans 86% des cas avec un cimentage Grade A dans 60% des cas. Le délai moyen de la survenue du descellement était de 12 ans. 72% des prothèses avaient une survie supérieure à 10 ans. L’analyse statistique des résultats a individualisé les facteurs de risque du descellement que sont: L’âge, l’indexe de masse corporelle, le niveau d’activité, l’inclinaison de la cupule, le déport fémoral et la qualité du cimentage.

Conclusion

Une réduction significative des descellements aseptiques des prothèses totales de hanche ne pourra être obtenue que par une plus grande rigueur dans la sélection des patients, une plus grande sûreté dans l’acte technique et un meilleur choix de l’implant à poser.

Clinical Factors, Disease Parameters, and Molecular Therapies Affecting Osseointegration of Orthopedic Implants

Total hip and knee arthroplasty are effective interventions for management of end-stage arthritis. Indeed, about 7 million Americans are currently living with artificial hip and knee joints. The majority of these individuals, however, will outlive their implants and require revision surgeries, mostly due to poor implant osseointegration and aseptic loosening. Revisions are potentially avoidable with better management of patient-related risk factors that affect the osseointegration of orthopedic implants. In this review, we summarize the published clinical literature on the role of demographics, biologic factors, comorbidities, medications and aseptic loosening risk. We focus on several systemic and local factors that are particularly relevant to implant osseointegration. Examples include physiological and molecular processes that are linked to hyperglycemia, oxidative stress, metabolic syndrome and dyslipidemia. We discuss how orthopedic implant osseointegration can be affected by a number of molecular therapies that are antiresorptive or bone anabolic (i.e. calcium, vitamin D, bisphosphonates, calcitonin, strontium, hormone replacement therapy, selective estrogen-receptor modulators).

Current tobacco use is associated with higher rates of implant revision and deep infection after total hip or knee arthroplasty: a prospective cohort study

BACKGROUND

Tobacco smoking is a risk factor for several adverse post-operative outcomes. We aimed to compare the rates of complications in current tobacco users and non-users who underwent primary total hip arthroplasty (THA) or total knee arthroplasty (TKA).

METHODS

All patients who underwent primary THA or TKA at the Mayo Clinic from 2010-2013 were included in the study. Current tobacco use was defined as the use of cigarettes, cigars, pipes, or smokeless tobacco reported at the time of index THA or TKA; current non-users were former users or never users. We used Cox proportional hazards regression to assess the association of current tobacco use status with each post-THA/TKA complication, using hazard ratios and 95% confidence intervals (CI).

RESULTS

Tobacco use status was available for 7926 patients (95%) and not available for 446 patients (5%); 565 (7%) were current tobacco users. Compared to non-users, current tobacco users were more likely to be male (p < 0.001), and less likely to be obese (p ≤ 0.008), be older than 60 years, have Charlson score >0 or have undergone TKA rather than THA (p < 0.001 each). The hazard ratios for deep infection (2.37; 95% CI 1.19, 4.72; p = 0.01) and implant revision (1.78; 95% CI 1.01, 3.13; p = 0.04) were higher in current tobacco users than in non-users. No significant differences were noted for periprosthetic fractures or superficial infections.

CONCLUSIONS

We noted that current tobacco use was associated with high risk of deep infection and implant revision after primary THA or TKA. Future studies should determine the optimal time for tobacco use cessation before elective surgeries such as THA and TKA to improve short-term and long-term arthroplasty outcomes.

Social and Behavioral Factors in Total Knee and Hip Arthroplasty

Social and behavioral factors are important determinants of health outcomes in a number of medical conditions but their role in joint arthroplasty is poorly understood. In a cohort of 20,124 hip and knee arthroplasty procedures, smoking was associated with a significantly higher risk of surgical site infections (hazard ratio 1.7, 95% CI: 1.1-2.6), whereas alcohol use was associated with a lower risk of reoperations and revisions (hazard ratio 0.7, 95% CI: 0.5-0.8). There was no association between marital status and educational attainment with the risk of complications or reoperations in total hip and knee arthroplasty.

Bone mineral density after implantation of a femoral neck hip prosthesis--a prospective 5 year follow-up

Background

Bone resorption in the proximal femur due to stress shielding has been observed in a number of conventional cementless implants used in total hip arthroplasty. Short femoral-neck implants are claiming less interference with the biomechanics of the proximal femur. The goal of this study was to prospectively investigate the in vivo changes of bone-mineral density as a parameter of bone remodeling around a short, femoral neck prosthesis over the first 5 years following implantation. The secondary goal was to report on its clinical outcome.

Methods

We are reporting on the changes of bone mineral density of the proximal femur and the clinical outcome up to five years after implantation of a short femoral neck prosthesis. Bone mineral density was determined using dual energy x-ray absorptiometry, performed 10 days, three, 12 and 60 months after surgery. 20 patients with a mean age of 47 years (range 17 to 65) were clinically assessed using the Harris Hip Score. The WOMAC was used as a patient-relevant outcome-measure.

Results

In contrast to conventional implants DEXA-scans overall revealed a slight increase of bone mineral density in the proximal femur in the 12 months following the implantation. The Harris Hip Score improved from an average preoperative score of 46 to a postoperative score at 12 months of 91 points and 95 points at 60 months, the global WOMAC index from 5.3 preoperatively to 0.8 at 12 months and 0.6 at 60 months postoperatively.

Conclusion

At 60 months after implantation of a short femoral neck prosthesis, all regions except one (region of interest #5) showed no significant changes in BMD compared to baseline measurements at 10 days which is less to the changes in bone mineral density seen in conventional implants.

Anterior Longitudinal Osteotomy of the Greater Trochanter in Total Hip Arthroplasty

The extra-articular impingement of the greater trochanter against the ileum is an underrated cause of early dislocation in total hip arthroplasty. In this preliminary study, the authors assess the effectiveness of an anterior longitudinal osteotomy of the greater trochanter for preventing dislocation. A total of 115 patients underwent a total hip arthroplasty through a posterolateral approach. All patients underwent clinical and radiological follow-up at 1, 3, and 6 months. No dislocation was reported. All patients demonstrated fast recovery of range of motion and walking. No trochanter fractures were observed. The osteotomy of the greater trochanter is an effective surgical technique that decreases anterior impingement and consequently lowers the dislocation rate in primary total hip arthroplasty. [Orthopedics. 2015; 38(8):490-493.].

What Host Factors Affect Aseptic Loosening After THA and TKA?

BACKGROUND

Aseptic loosening is the most common cause for revisions after lower-extremity total joint arthroplasties, however studies differ regarding the degree to which host factors influence loosening.

QUESTIONS/PURPOSE

We performed a systematic review to determine which host factors play a role in the development of clinical and/or radiographic failure from aseptic loosening after (1) THA and (2) TKA.

METHODS

Two searches on THA and TKA, respectively, using four electronic databases (EMBASE, CINAHL Plus, PubMed, and Scopus) were conducted. We identified a total of 209 reports that encompassed nine potential host factors affecting aseptic loosening. Inclusion criteria for consideration of scientific clinical reports were that 20 or more patients were involved, with more than 1-year followup, with at least three studies pertaining to each factor, and at least six of the Methodological Index for Non-randomized Studies criteria met, and with raw data for odds ratio (OR) calculations. Twenty-one studies (16 THA studies with 45,779 hips and five TKA studies with 288 knees, respectively) were used to calculate weighted OR and CIs (using the random effects theory) and study heterogeneity for four different host factors in THAs (male sex, high activity level, obesity defined as BMI≥30 kg/m2, and current or former tobacco use) and one factor in TKA (BMI≥30 kg/m2), which were placed in a forest plot.

RESULTS

For THA, male sex (OR, 1.39; 95% CI, 1.22-1.58; p=0.001) and high activity level (University of California Los Angeles [UCLA] activity score≥8 points; OR, 4.24; 95% CI, 2.46-7.31; p=0.001) were associated with aseptic loosening. However, obesity (OR, 1.01; 95% CI, 0.73-1.40; p=0.96), and tobacco use (OR, 1.96; 95% CI, 0.43-8.97; p=0.39) were not associated with an increased risk of aseptic loosening after THA with the numbers available. For TKA, we found no host factors associated with loosening. In particular, obesity (BMI≥30 kg/m2) was not associated with aseptic loosening with the numbers available (OR, 2.28; 95% CI, 0.60-8.62; p=0.22).

CONCLUSIONS

Patients undergoing a lower-extremity total joint arthroplasty who engage in impact sports should be counseled regarding their potential increased risk of aseptic loosening; however, given the weak evidence available, we believe that higher-level studies are necessary to clearly define the risk factors, particularly with newer-generation constructs.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

The Effect of Smoking on Short-Term Complications Following Total Hip and Knee Arthroplasty

BACKGROUND

Total joint arthroplasty is the most frequently performed orthopaedic procedure in the United States. The purpose of the present study was to identify differences in thirty-day morbidity and mortality following primary total hip and total knee arthroplasty according to smoking status and pack-year history of smoking.

METHODS

We queried the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) database to identify patients who had undergone primary total hip or total knee arthroplasty between 2006 and 2012. Patients were stratified by smoking status and pack-year history of smoking. Thirty-day rates of mortality, wound complications, and total complications were compared with use of univariate and multivariate analyses.

RESULTS

We identified 78,191 patients who had undergone primary total hip or total knee arthroplasty. Of these, 81.8% (63,971) were nonsmokers, 7.9% (6158) were former smokers, and 10.3% (8062) were current smokers. Current smokers had a higher rate of wound complications (1.8%) compared with former smokers and nonsmokers (1.3% and 1.1%, respectively; p < 0.001). Former smokers had a higher rate of total complications (6.9%) compared with current smokers and nonsmokers (5.9% and 5.4%, respectively; p < 0.001). Multivariate analysis identified current smokers as being at increased risk of wound complications (odds ratio [OR], 1.47; 95% confidence interval [CI], 1.21 to 1.78), particularly deep wound infection, while both current smokers (OR, 1.18; 95% CI, 1.06 to 1.31) and former smokers (OR, 1.20; 95% CI, 1.08 to 1.34) were at increased total complication risk. Increasing pack-year history of smoking resulted in increasing total complication risk.

CONCLUSIONS

On the basis of our findings, current smokers have an increased risk of wound complications and both current and former smokers have an increased total complication risk following total hip or total knee arthroplasty.

Tobacco use may be associated with increased revision and complication rates following total hip arthroplasty

The purpose of this study was to compare the clinical outcomes of total hip arthroplasty in patients who were smokers to patients who were non-smokers. All total hip arthroplasties performed between 2007 and 2009 were reviewed to identify patients who indicated tobacco use. There were 110 smokers who were matched in a 1:2 ratio to 220 non-smoking patients. At a mean follow-up of 51 months (range, 24 to 72 months), smokers had an overall significantly lower survivorship of 92% (n = 9 revisions), compared to 99% (n = 2 revisions) in non-smokers. In addition, there were five complications in smokers (one pneumonia, three superficial infections, and one deep peroneal nerve palsy) compared to none in non-smokers. These results indicate that patients who smoke had higher overall revisions and postoperative complications.

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

Background

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

Material/Methods

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

Results

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

Conclusions

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

Macrophages-Key cells in the response to wear debris from joint replacements

The generation of wear debris is an inevitable result of normal usage of joint replacements. Wear debris particles stimulate local and systemic biological reactions resulting in chronic inflammation, periprosthetic bone destruction, and eventually, implant loosening, and revision surgery. The latter may be indicated in up to 15% patients in the decade following the arthroplasty using conventional polyethylene. Macrophages play multiple roles in both inflammation and in maintaining tissue homeostasis. As sentinels of the innate immune system, they are central to the initiation of this inflammatory cascade, characterized by the release of proinflammatory and pro-osteoclastic factors. Similar to the response to pathogens, wear particles elicit a macrophage response, based on the unique properties of the cells belonging to this lineage, including sensing, chemotaxis, phagocytosis, and adaptive stimulation. The biological processes involved are complex, redundant, both local and systemic, and highly adaptive. Cells of the monocyte/macrophage lineage are implicated in this phenomenon, ultimately resulting in differentiation and activation of bone resorbing osteoclasts. Simultaneously, other distinct macrophage populations inhibit inflammation and protect the bone-implant interface from osteolysis. Here, the current knowledge about the physiology of monocyte/macrophage lineage cells is reviewed. In addition, the pattern and consequences of their interaction with wear debris and the recent developments in this field are presented.

Use of kernel-based Bayesian models to predict late osteolysis after hip replacement

We studied the relationship between osteolysis and polyethylene wear, age at surgery, body mass index and height in 463 subjects (180 osteolysis and 283 controls) after cemented Charnley total hip arthroplasty (THA), in order to develop a kernel-based Bayesian model to quantitate risk of osteolysis. Such tools may be integrated into decision-making algorithms to help personalize clinical decision-making. A predictive model was constructed, and the estimated posterior probability of the implant failure calculated. Annual wear provided the greatest discriminatory information. Age at surgery provided additional predictive information and was added to the model. Body mass index and height did not contain valuable discriminatory information over the range in which observations were densely sampled. The robustness and misclassification rate of the predictive model was evaluated by a five-times cross-validation method. This yielded a 70% correct predictive classification of subjects into osteolysis versus non-osteolysis groups at a mean of 11 years after THA. Finally, the data were divided into male and female subsets to further explore the relationship between wear rate, age at surgery and incidence of osteolysis. The correct classification rate using age and wear rate in the model was approximately 66% for males and 74% for females.

Alcohol use in elective total hip arthroplasty: risk or benefit?

BACKGROUND

Excessive alcohol consumption has been associated with adverse health measures after elective surgery. The effects of low or moderate consumption remain unclear.

QUESTION/PURPOSES

We determined differences among patients with different consumption levels in (1) preoperative and postoperative patient-perceived outcomes and hip scores, (2) changes in those scores from preoperatively to postoperatively, (3) demographics and comorbidities, and (4) length of stay (LOS) and hospitalization charges.

METHODS

We retrospectively reviewed 191 patients (218 primary hips). Based on a self-administered consumption questionnaire, patients were stratified into three groups: (1) nondrinkers (n = 52), (2) occasional drinkers (n = 56), and (3) moderate drinkers (n = 17). Demographics, BMI, Charlson Comorbidity Index, and American Society of Anesthesiologists grade; preoperative and postoperative Quality of Well-being Scale, SF-36, WOMAC, Harris hip, and Merle d'Aubigné-Postel hip scores; and LOS and hospital charges were obtained and compared among groups adjusting for patient characteristics. Minimum followup was 1 year (mean, 3.5 years; range, 1-6 years).

RESULTS

Most abstainers were older, female, and Hispanic. Preoperatively, moderate drinkers had better WOMAC function and total scores and Harris hip scores. There were no differences postoperatively among groups. However, nondrinkers had greater improvement (preoperative to postoperative) in the WOMAC function, pain, and total scores. Compared to nondrinkers, moderate drinkers had a higher contribution margin and net income.

CONCLUSIONS

Alcohol consumption is more common among men and non-Hispanics. Moderate consumption was associated with better WOMAC and Harris hip scores. After surgery, abstainers achieved greater improvements in the WOMAC function, pain, and total scores.

LEVEL OF EVIDENCE

Level III, prognostic study. See the Instructions for Authors for a complete description of levels of evidence.

Arthroplasty knee surgery and alcohol use: risk factor or benefit?

BACKGROUND

Excessive alcohol consumption has been associated with adverse measures of health after elective surgery. However, associations of low/moderate consumption remain uncertain.

QUESTION/PURPOSES

We determined differences among patients with three different self-reported consumption levels in (1) preoperative/postoperative patient-perceived outcomes and knee scores, (2) preoperative/postoperative changes in these scores, (3) preoperative demographics and comorbidities, and (4) length of stay (LOS) and inpatient charges.

METHODS

We retrospectively studied 430 patients (545 TKAs). Based on a self-administered consumption questionnaire, patients were stratified into groups: (1) nondrinkers, (2) occasional drinkers, and (3) moderate drinkers. We compared the following variables between groups: demographics, BMI, American Society of Anesthesiologists score, Charlson Comorbidity Index, preoperative and postoperative Quality of Well-being Index (QWB-7), SF-36 score, WOMAC score, Knee Society (KS) Score, Hospital for Special Surgery (HSS) knee score, LOS, and hospital charges. QWB-7, SF-36, WOMAC, KS, and HSS scores were compared adjusting for patient characteristics. Minimum followup was 1 year (average, 3.4 years; range, 1-6 years).

RESULTS

Preoperatively, compared to self-reported nondrinkers, moderate drinkers had better QWB-7, SF-36, and WOMAC scores. At followup, occasional and moderate drinkers had better KS function and HSS scores. However, nondrinkers had greater SF-36 general health improvement. Most nondrinkers were older, female, and Hispanic and had more comorbidities. Nondrinkers had a longer LOS.

CONCLUSIONS

Self-reported alcohol consumption was more common among men and non-Hispanics. Moderate drinkers had better preoperative QWB-7, SF-36, and WOMAC scores and shorter LOS than nondrinkers. However, after surgery, self-reported abstainers achieved greater improvements in the SF-36 general health score.

Pseudoacetabulum a subtle radiological feature of a chronic dislocated total hip replacement

We report the presence of an unusual radiological feature of formation of pseudoacetabulum in a chronically dislocated and asymptomatic total hip arthroplasty. An elderly demented patient with a history of recurrent dislocations presented to us after an unwitnessed fall and leg length discrepancy. Radiographs showed a dislocated hip arthroplasty with a well-defined, concentric, radio-opaque shadow around the dislocated femoral head suggestive of a pseudoacetabulum. Previous radiographs revealed formation of heterotopic ossification in the soft tissues surrounding the hip. The dislocated joint was reduced under a general anaesthetic with difficulty. This case highlights the presence of heterotopic ossification and formation of pseudoacetabulum as subtle radiological features of chronic instability and dislocation.

Risk of dislocation using large- vs. small-diameter femoral heads in total hip arthroplasty

Background

Dislocation remains a difficult problem in total hip arthroplasty. Large-diameter femoral heads may lower the incidence of dislocation by enhancing the jump distance and decreasing impingement, but their performance against small-diameter heads has not been assessed. This study compared the mid-term radiographic and functional outcomes of two matched cohorts of patients undergoing total hip arthroplasty who had a high pre-operative risk for dislocation and who received either small-diameter (26- or 28-millimeters) or large-diameter (≥36-millimeters) femoral heads.

Methods

All patients who received large-diameter heads (≥36-millimeter) between 2002 and 2005, and who had pre-operative risk factors for dislocation, were identified in the institution’s joint registry. Forty-one patients (52 hips) who received large-diameter heads were identified, and these patients were matched to 48 patients (52 hips) in the registry who received small-diameter femoral heads.

Results

At mean final follow-up of 62 months (range, 49 to 101 months), both groups achieved excellent functional outcomes as measured by Harris Hip scores, with slightly better final scores in the large-diameter group (90 vs. 83 points). No patient showed any radiographic signs of loosening. No patient dislocated in the large-diameter femoral head group; the smaller-diameter group had a greater rate of dislocation (3.8%, 2 out of 52).

Conclusions

Large-diameter femoral head articulations may reduce dislocation rates in patients who have a high pre-operative risk for dislocation while providing the same functional improvements and safety as small-diameter bearings.

Acute delirium and poor compliance in total hip arthroplasty patients with substance abuse disorders

From the joint registry of 2831 primary total hip arthroplasties (2351 patients) performed between 1998 and 2003, we identified 15 patients (16 hips) who had a documented history of substance abuse disorders at the time of the index surgery. The patients included 13 men (14 hips) and 2 women (2 hips), with the mean age of 49 years (range, 29-65 years). On the basis of the criteria specified in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, 13 patients had alcohol abuse disorders, 1 had amphetamine abuse disorder, and 1 had heroin abuse disorder. We found high rates of postoperative substance withdrawal delirium and psychosis (46%), late complication (25%), and lost to follow-up (27%) in these patients. Because patients with substance abuse disorders have unexpected perioperative psychotic episodes, poor compliance, and a tendency to not follow medical advice after surgery and show early discontinuation of follow-up, we suggest that surgeons should work with other medical professionals and carefully perform total hip arthroplasty in such patients.

Stress-related femoral cortical and cancellous bone density loss after collum femoris preserving uncemented total hip arthroplasty: a prospective 7-year follow-up with quantitative computed tomography

PURPOSE

Bone loss around uncemented femoral components is suspected to precede implant loosening and contribute to problems in revision surgery. Short-stemmed cementless femoral components are designed to preserve proximal femoral bone stock and ultimately the longevity of the prosthesis.

METHODS

With quantitative computed tomography-assisted osteodensitometry, we prospectively analyzed femoral cortical and cancellous bone density (BD) and contact area changes of an uncemented collum femoris preserving stem (n = 38) 10 days, 1, 3 and 7 years post-operatively.

RESULTS

Seven years post-operatively, cancellous BD (mg CaHA/mL) had decreased by as much as -66 % and cortical BD by up to -27 % at the metaphyseal portion of the femur; the decrease was progressive between the 1- and 3-year examinations and halted thereafter. Contact area (in % out of a possible 100 %) decreased proximally between the 1- and 3-year follow-up.

CONCLUSION

Proximal cortical and cancellous bone density loss and decrease of contact area indicate that metaphyseal fixation cannot be achieved. The lack of cortical BD loss and increase of contact area values below the trochanter minor suggest diaphyseal fixation.

Periacetabular cortical and cancellous bone mineral density loss after press-fit cup fixation: a prospective 7-year follow-up

The impact of total hip arthroplasty on strain adaptive bone remodeling has been extensively analyzed by dual-energy x-ray absorptiometry. In this study, we present a prospective computed tomography-assisted study of periacetabular cortical and cancellous bone mineral density (in milligrams of calcium hydroxyapatite [CaHA] per milliliter, or mgCaHA/mL) changes 10 days and 1, 3, and 7 years after press-fit cup implantation for 38 hips in vivo. Cancellous bone mineral density decreased by Ø -63% ventral and Ø -85% dorsal to the cup; cortical bone mineral density, by Ø -22% ventral and Ø -18% dorsal to the cup. The presented periacetabular strain adaptive bone mineral density data are the most extensive of the current literature. Even the measured extensive cancellous bone mineral density loss was thus far of no clinical relevance because all cups showed radiographic signs of stable ingrowth.

Total hip replacement in patients with history of illicit injecting drug use

BACKGROUND

A history of illicit injecting drug use makes indication of total hip arthroplasty (THA) in patients with end stage hip osteoarthritis difficult, as the risk of infection with colonized strains is multiplied if the patient continues to inject or inhale illicit drugs.

METHODS

A retrospective survivorship analysis of a consecutive series of 27 THA in patients with a history of illicit drug use was performed. Follow-up evaluation consisted of (1) a WOMAC score, (2) a standardized interview including queries on drug habits and eventual additional medico-surgical treatments of the affected hip, (3) a clinical examination in order to complete a Harris Hip Score, (4) radiological examination and (5) blood tests (blood sedimentation rates and C-reactive protein). Defined endpoints were death, implant revised or awaiting revision for deep infection or any other reason and lost to follow-up or follow-up after at least 2 years.

RESULTS

Overall, 5- and 10-year implant survival rates with failure for any reason were 61 % (CI: 41;81) and 52.3 % (CI: 29;76) and for septic reasons 70.6 % (CI: 52;89) and 60.5 % (CI: 36;85), respectively. Even if at the time of THA all patients and respective health care professionals confirmed abstinence of illicit injecting drug use, five patients reported occasional use. Declared abstinence of less than 1 year before THA was associated with higher recurrence rates (p = 0.001) and both with higher septic failure rates (p = 0.023, p = 0.061). Positive serology for human deficiency virus did not increase implant failure rates.

CONCLUSION

We use this unacceptable high failure rate as evidence when counseling patients and their health care professionals about the appropriate treatment of osteoarthritis in patients with a history of illicit drug use. Furthermore, we support the request of hair analysis for drugs documenting abstinence of at least 1 year before indicating THA.

[Periprosthetic femoral bone reaction after total hip arthroplasty with preservation of the collum femoris : CT-assisted osteodensitometry 1 and 3 years postoperatively]

BACKGROUND

Short-stemmed cementless femoral components in total hip arthroplasty have been designed to preserve the proximal femoral bone stock by load transfer to the femoral metaphysis. An in vivo method of computed tomography-assisted (CT) osteodensitometry after total hip arthroplasty is presented which differentiates between cortical and cancellous bone density (BD) changes around uncemented femoral components.

PATIENTS AND METHODS

Cortical and cancellous periprosthetic femoral BD (mg Ca HA/ml) was determined prospectively in 31 patients at day 10, 1 year and 3 years after total hip arthroplasty with preservation of the collum femoris (C.F.P.-stem, Link, Hamburg, Germany) using computed tomography-assisted osteodensitometry. Clinical results (Harris hip score) and plain x-rays were assessed in all cases.

RESULTS

Progressive proximal cortical BD loss was observed between the 1 year (Ø -8%) and 3 year (Ø -22%) postoperative measurements. Distal to the trochanter minor no significant cortical BD changes were observed. Proximal cancellous BD decreased progressively between the 1 year (Ø -33%) and 3 year (Ø -45%) analyses. The Harris hip score improved from 45 points pre-operatively to 93 points at the 3 year follow-up. All x-rays showed signs of stable ingrowth.

CONCLUSION

Periprosthetic CT osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Progressive proximal cortical and cancellous BD loss indicates that metaphyseal fixation cannot be achieved with the analyzed C.F.P. stem design. The lack of cortical BD loss below the trochanter minor suggests diaphyseal fixation of the implanted stem.

Predictors of early stem loosening after total hip arthroplasty: a case-control study

PURPOSE

To evaluate the influence of patient characteristics on stem loosening after cemented or uncemented total hip arthroplasty (THA) using a matched case-control study. METHODS; Consecutive records of 4372 cemented (716 cases and 3656 controls) and 809 uncemented (115 cases and 694 controls) primary THAs between 1981 and 2003 in 30 hospitals in 8 European countries were reviewed. Cases and controls were defined as patients with and without stem loosening, respectively. In cases of bilateral THA, patients were their own controls. Cases and controls were matched for hospital, date of surgery, date of follow-up, stem type, and head size. Patient characteristics such as gender, age, weight, height, body mass index (BMI), diagnosis, presence of previous surgery on the affected hip, and walking restrictions according to the Charnley classification were recorded.

RESULTS

Male patients were at higher risk of cemented stem loosening (odds ratio [OR], 1.76; 95% confidence interval [CI], 1.4-2.2). Older patients were at lower risk of cemented stem loosening; the odds decreased by 3% per year older (OR, 0.97; 95% CI, 0.96-0.98). Regarding BMI, the odds of cemented stem loosening increased by 3% for each additional unit of BMI over 25 kg/m² square (OR, 1.03; 95% CI, 1.004-1.05). Patients in Charnley class B had a lower risk of cemented stem loosening (OR, 0.75; 95% CI, 0.61-0.93).

CONCLUSION

Advanced age, female gender, and Charnley class B (as a proxy measure of reduced walking activity) have a protective effect on survival of cemented stems, whereas a higher BMI was a risk factor.

Influence of patient activity on femoral osteolysis at five and ten years following hybrid total hip replacement

We conducted a longitudinal study including patients with the same type of primary hybrid total hip replacement and evaluated patient activity and femoral osteolysis at either five or ten years post-operatively. Activity was measured using the University of California, Los Angeles scale. The primary outcome was the radiological assessment of femoral osteolysis. Secondary outcomes were revision of the femoral component for aseptic loosening and the patients' quality of life. Of 503 hip replacements in 433 patients with a mean age of 67.7 years (30 to 91), 241 (48%) were seen at five and 262 (52%) at ten years post-operatively. Osteolytic lesions were identified in nine of 166 total hip replacements (5.4%) in patients with low activity, 21 of 279 (7.5%) with moderate activity, and 14 of 58 (24.1%) patients with high activity. The risk of osteolysis increased with participation in a greater number of sporting activities. In multivariate logistic regression adjusting for age, gender, body mass index and the inclination angle of the acetabular component, the adjusted odds ratio for osteolysis comparing high vs moderate activity was 3.6 (95% confidence interval 1.6 to 8.3). Stratification for the cementing technique revealed that lower quality cementing increased the effect of high activity on osteolysis. Revision for aseptic loosening was most frequent with high activity. Patients with the highest activity had the best outcome and highest satisfaction. In conclusion, of patients engaged in high activity, 24% had developed femoral osteolysis five to ten years post-operatively.

Smoking and outcomes after knee and hip arthroplasty: a systematic review

OBJECTIVE

Studies have suggested higher rates of perioperative and postoperative complications in smokers compared to nonsmokers. The objective of this systematic review was to assess the association of smoking and postoperative outcomes following total hip arthroplasty (THA) or total knee arthroplasty (TKA).

METHODS

A search of 6 databases (The Cochrane Library, Scopus, Proquest Dissertation abstracts, CINAHL, Ovid Medline, and Embase) was performed by a Cochrane librarian. All titles and abstracts were screened by 2 independent reviewers with expertise in performing systematic reviews. Studies were included if they were fully published reports that included smoking and any perioperative or postoperative clinical outcome in patients with TKA or THA.

RESULTS

A total of 21 studies were included for the review, of which 6 provided multivariable-adjusted analyses, 14 univariate analyses, and one statistical modeling. For most outcomes, results from 1-2 studies could be pooled. Current smokers were significantly more likely to have any postoperative complication (risk ratio 1.24, 95% CI 1.01 to 1.54) and death (risk ratio 1.63, 95% CI 1.06 to 2.51) compared to nonsmokers. Former smokers were significantly more likely to have any post-operative complication (risk ratio 1.32, 95% CI 1.05 to 1.66) and death (risk ratio 1.69, 95% CI 1.08 to 2.64) compared to nonsmokers.

CONCLUSION

This systematic review found that smoking is associated with significantly higher risk of postoperative complication and mortality following TKA or THA. Studies examining longterm consequences of smoking on implant survival and complications are needed. Smoking cessation may improve outcomes after THA or TKA.

Choice of hospital for revision total hip replacement

BACKGROUND

Little is known about how often patients have revision total hip replacement in the same hospital in which they had the primary procedure.

METHODS

We examined Medicare claims data to identify patients who had primary total hip replacement from July 1995 to June 1996 and subsequently had revision through December 31, 2006. We examined whether the revision was performed in the same or different hospital from the primary procedure, with different hospitals being categorized as being in a lower, a higher, or the same hospital volume stratum. Hospital strata included twenty-five or fewer cases of total hip replacement annually in the Medicare population, twenty-six to fifty cases, fifty-one to 100 cases, and >100 cases. We calculated the number of revisions generated (primary procedures eventuating in revision) by hospitals in each volume stratum and the number of revisions performed in these hospitals.

RESULTS

Of 4448 revision procedures, 3306 (74%) were performed in hospitals in the same volume stratum as the hospital where the primary procedure was performed. Four hundred twenty-nine revisions (9.6%) were performed in a lower-volume hospital, and 713 (16%) were performed in a higher-volume hospital. Thirty-one (3%) of 960 patients who had revision within one year after the primary total hip replacement had the revision in a lower-volume center, compared with 204 (15%) of 1393 who had revision more than six years after the primary procedure (odds ratio = 4.6 ; 95% confidence interval, 3.0 to 6.8). The ratio of revisions performed to revisions generated was 1.21 for the highest-volume centers and 0.86 for the lowest-volume centers.

CONCLUSIONS

Of 4448 revisions examined in this study, 429 (<10%) were performed in centers with a lower volume of total hip replacement than the center at which the initial hip replacement was performed, whereas 713 (16%) were performed in higher-volume centers. Higher-volume centers performed 21% more revisions than they generated (531 revisions performed, compared with 438 generated). These data will help to inform health-care policy with regard to the utilization of resources for revision total hip replacement.

Repeat 2-stage revision for recurrent infection of total hip arthroplasty

Eleven patients who developed reinfection after 2-stage revision for infected total hip arthroplasty (THA) were treated with a repeat 2-stage rerevision. Of the 11 rerevisions, 4 were successful, with no recurrent infection at mean follow-up of 44 months. Reinfection occurred in 7 patients of whom 6 involved either a significantly compromised host or poor local wound status. Clinical symptoms of infection were controlled in 4 of the 7 reinfected cases with antibiotic therapy in 2, irrigation and debridement in 1, and a third 2-stage revision THA in 1. Repeat 2-stage treatment of infected THA is associated with a high failure rate. However, successful results can be achieved particularly if the host is not immunocompromised and healthy soft tissue coverage is present.

Obesity, age, sex, diagnosis, and fixation mode differently affect early cup failure in total hip arthroplasty: a matched case-control study of 4420 patients

BACKGROUND

Studies about the influence of patient characteristics on mechanical failure of cups in total hip replacement have applied different methodologies and revealed inconclusive results. The fixation mode has rarely been investigated. Therefore, we conducted a detailed analysis of the influence of patient characteristics and fixation mode on cup failure risks.

METHODS

We conducted a case-control study of total hip arthroplasties in 4420 patients to test our hypothesis that patient characteristics of sex, age, weight, body mass index, and diagnosis have different influences on risks for early mechanical failure in cemented and uncemented cups.

RESULTS

Women had significantly reduced odds for failure of cups with cemented fixation (odds ratio = 0.59; 95% confidence interval, 0.43 to 0.83; p = 0.002) and uncemented fixation (odds ratio = 0.63; 95% confidence interval, 0.5 to 0.81; p = 0.0003) compared with that for men (odds ratio = 1). Each additional year of patient age at the time of surgery reduced the failure odds by a factor of 0.98 for both cemented cups (odds ratio = 0.98; 95% confidence interval, 0.96 to 0.99; p = 0.016) and uncemented cups (odds ratio = 0.98; 95% confidence interval, 0.97 to 0.99; p = 0.0002). In patients with cemented cups, the weight group of 73 to 82 kg had significantly lower failure odds (odds ratio = 0.63; 95% confidence interval, 0.4 to 0.98) than the lightest (<64 kg) weight group or the heaviest (>82 kg) weight group (odds ratios = 1.00 and 1.07, respectively). No significant effects of weight were noted in the uncemented group. In contrast, obese patients (a body mass index of >30 kg/m(2)) with uncemented cups had significantly elevated odds relative to patients with a body mass of <25 kg/m(2) (odds ratio = 1.41; 95% confidence interval, 1.03 to 1.91) for early failure of the cups compared with an insignificant effect in the cemented arm of the study. Compared with osteoarthritis as the reference diagnosis (odds ratio = 1), developmental dysplasia (odds ratio = 0.52; 95% confidence interval, 0.28 to 0.97) and hip fracture (odds ratio = 0.38; 95% confidence interval, 0.16 to 0.92) were significantly protective in cemented cups.

CONCLUSIONS

Female sex and older age have similarly protective effects on the odds for early failure of cemented and uncemented cups. Although a certain body-weight range has a significant protective effect in cemented cups, the more important finding was the significantly increased risk for failure of uncemented cups in obese patients. Patients with developmental dysplasia and hip fracture were the only diagnostic groups with a significantly decreased risk for cup failure, but only with cemented fixation.

LEVEL OF EVIDENCE

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

Influence of obesity on femoral osteolysis five and ten years following total hip arthroplasty

BACKGROUND

The most important long-term complication following total hip arthroplasty is periprosthetic femoral osteolysis. A sizeable proportion of patients who undergo arthroplasty are obese. While patient activity, implant type, and quality of fixation are known risk factors for osteolysis, the literature concerning obesity is sparse and controversial. Our primary objective was to evaluate the influence of obesity on the risk of osteolysis five and ten years after primary total hip arthroplasty with a cemented stem. Secondary objectives were to evaluate clinical outcome and patient satisfaction.

METHODS

We conducted a prospective cohort study of patients undergoing hip arthroplasty with a third-generation stem-cementing technique from 1996 to 2003. All patients were seen at five or ten years postoperatively. Radiographs and information regarding body-mass index (<25 kg/m(2) = normal weight, 25 to 29.9 kg/m(2) = overweight, and > or = 30 kg/m(2) = obese) and activity were obtained. Activity was assessed with use of the University of California at Los Angeles (UCLA) activity scale. Osteolysis was assessed radiographically. Clinical outcome measurements included the Harris hip and Merle d'Aubigné and Postel scores.

RESULTS

Our study included 503 arthroplasties in 433 patients; the results of 241 (47.9%) of the arthroplasties were evaluated at five years and the results of 262 (52.1%), at ten years. Osteolysis was identified around forty-four stems, with twenty-four (13.3%) in 181 hips of normal-weight patients, eleven (5.4%) in 205 hips of overweight patients, and nine (7.7%) in 117 hips of obese patients. Normal-weight patients had the highest activity level (mean UCLA activity scale score [and standard deviation], 5.5 + or - 2.0 points), and obese patients had the lowest (mean UCLA activity scale score, 5.0 + or - 1.7 points). When adjusted for activity, cementing quality, and patient age and sex, the risk of osteolysis in obese patients was not increased as compared with that for overweight patients (adjusted odds ratio, 1.4; 95% confidence interval, 0.6 to 3.7), whereas the risk of femoral osteolysis in normal-weight patients was found to be significantly higher than that in overweight patients (adjusted odds ratio, 2.6; 95% confidence interval, 1.2 to 5.7). Clinical outcomes were similar among the groups.

CONCLUSIONS

We found no increased risk of osteolysis around a cemented femoral stem in obese patients five and ten years after primary total hip arthroplasty. The highest prevalence of osteolysis was observed in normal-weight patients.

LEVEL OF EVIDENCE

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

Progressive femoral cortical and cancellous bone density loss after uncemented tapered-design stem fixation

BACKGROUND

Aseptic implant loosening and periprosthetic bone loss are major problems after total hip arthroplasty (THA). We present an in vivo method of computed tomography (CT) assisted osteodensitometry after THA that differentiates between cortical and cancellous bone density (BD) and area around the femoral component.

METHOD

Cortical and cancellous periprosthetic femoral BD (mg CaHA/mL), area (mm(2)) and contact area between the prothesis and cortical bone were determined prospectively in 31 patients 10 days, 1 year, and 6 years after uncemented THA (mean age at implantation: 55 years) using CT-osteodensitometry.

RESULTS

6 years postoperatively, cancellous BD had decreased by as much as 41% and cortical BD by up to 27% at the metaphyseal portion of the femur; this decrease was progressive between the 1-year and 6-year examinations. Mild cortical hypertrophy was observed along the entire length of the diaphysis. No statistically significant changes in cortical BD were observed along the diaphysis of the stem.

INTERPRETATION

Periprosthetic CT-assisted osteodensitometry has the technical ability to discriminate between cortical and cancellous bone structures with respect to strain-adapted remodeling. Continuous loss of cortical and cancellous BD at the femoral metaphysis, a homeostatic cortical strain configuration, and mild cortical hypertrophy along the diaphysis suggest a diaphyseal fixation of the implanted stem. CT-assisted osteodensitometry has the potential to become an effective instrument for quality control in THA by means of in vivo determination of periprosthetic BD, which may be a causal factor in implant loosening after THA.

Does smoking influence outcome after autologous chondrocyte implantation?

Smoking is known to have an adverse effect on wound healing and musculoskeletal conditions. This case-controlled study looked at whether smoking has a deleterious effect in the outcome of autologous chondrocyte implantation for the treatment of full thickness chondral defects of the knee.

The mean Modified Cincinatti Knee score was statistically significantly lower in smokers (n = 48) than in non-smokers (n = 66) both before and after surgery (p < 0.05). Smokers experienced significantly less improvement in the knee score two years after surgery (p < 0.05). Graft failures were only seen in smokers (p = 0.016). There was a strong negative correlation between the number of cigarettes smoked and the outcome following surgery (Pearson’s correlation coefficient −0.65, p = 0.004).

These results suggest that patients who smoke have worse pre-operative function and obtain less benefit from this procedure than non-smokers. The counselling of patients undergoing autologous chondrocyte implantation should include smoking, not only as a general cardiopulmonary risk but also because poorer results can be expected in smokers following this procedure.