The Influence of Obesity on Hip Pain, Function, and Satisfaction 10 Years Following Total Hip Arthroplasty.

BACKGROUND: The prevalence of obesity is rising, and increasing numbers of joint arthroplasty surgeries are being performed on obese patients. Concern exists that obesity increases surgical risk; however, its impact on function following total hip arthroplasty (THA) is inconsistently affirmed and less understood. A paucity exists in the literature pertaining long-term objective functional measures. Therefore, we investigated the impact of obesity on hip pain, function, and satisfaction 10 years following THA. METHODS: This single-center, prospective, observational study categorized consecutive THA patients according to their body mass index to nonobese (<30 kg/m2) and obese (≥30 kg/m2) groups. Preoperative assessment included a numerical pain rating and the Oxford Hip Score. These were repeated along with a 6-minute walk test and a Likert satisfaction scale at 3 months, 1, 5, and 10 years postoperatively. RESULTS: The series included 191 primary THA patients. No significant differences were found in hip pain or function between the obese and nonobese groups. Obese patients however had poorer walking capacity (P = .008), were more likely to use walking aids (P = .04), and were less satisfied (P = .04) at 10 years. CONCLUSION: THA confers significant long-term symptom resolution irrespective of obesity; however, despite undergoing surgery, obese patients can be counseled they may not be as satisfied as or achieve the same walking capacity as nonobese individuals.

Sliding hip screws versus cancellous screws for femoral neck fractures: a systematic review and meta-analysis.

PURPOSE: Both sliding hip screws (SHS) and cancellous screws are used in the surgical management of intracapsular femoral neck fracture. However, there is paucity of information as to which is the superior treatment modality. We performed this systematic review and meta-analysis study to compare the clinical outcomes of SHS and cancellous screws for the treatment of femoral neck fractures in adult patients. METHODS: We searched PubMed, Scopus, Web of Science, and Cochrane CENTRAL, up to December 2017. Randomized controlled trials (RCTs) directly comparing the clinical outcomes of SHS and cancellous screws for femoral neck fractures were retrieved with no language or publication year restrictions. Data retrieved included operative details, nonunion rate, avascular necrosis, reoperation, infection and mortality, hip pain, functional hip scores, and medical complications. These were pooled as risk ratio or mean difference (MD) with their corresponding 95% confidence interval (CI). Heterogeneity was assessed by Chi-square test. RESULTS: Ten RCTs involving 1934 patients were included in the final analysis. The pooled estimate showed that the SHS group was associated with more intraoperative blood loss (MD = 110.01 ml, 95% CI [52.42, 167.60], p = 0.00002) than the cancellous screws. There was no significant difference in terms of operative time, postoperative hip function, nonunion, avascular necrosis, reoperation rate, infection, fracture healing, hip pain, medical complications, and mortality rate. CONCLUSION: Based on our study, the cancellous screws group was associated with less intraoperative blood loss in comparison with the SHS group. No other significant differences were found between the two interventions.

A new technique for radiographic measurement of acetabular cup orientation.

Accurate radiographic measurement of acetabular cup orientation is required in order to assess susceptibility to impingement, dislocation, and edge loading wear. In this study, the accuracy and precision of a new radiographic cup orientation measurement system were assessed and compared to those of two commercially available systems. Two types of resurfacing hip prostheses and an uncemented prosthesis were assessed. Radiographic images of each prosthesis were created with the cup set at different, known angles of version and inclination in a measurement jig. The new system was the most accurate and precise and could repeatedly measure version and inclination to within a fraction of a degree. In addition it has a facility to distinguish cup retroversion from anteversion on anteroposterior radiographs.

Imaging Metal-on-Metal Hip Replacements: the Norwich Experience.

BACKGROUND: Adverse reaction to metal debris is a relatively recently described and often a silent complication of metal-on-metal (MOM) total hip replacements (THR). The Norfolk & Norwich University Hospital has been performing metal artefact reduction (MARS) MRI for 8 years in a variety of different types of MOM THR. QUESTIONS/PURPOSES: The aims of this review are to describe the experience of using MARS MRI in Norwich and to compare our experience with that published by other groups. METHODS: A MEDLINE keyword search was performed for studies including MRI in MOM THR. Relevant publications were reviewed and compared with published data from the Norfolk & Norwich University Hospital. The similarities and differences between these data were compared and possible explanations for these discussed. RESULTS: MARS MRI appears to be the most useful tool for diagnosing, staging and monitoring adverse reactions to metal debris (ARMD). There appears to be no clinically useful association between clinical and serological markers of disease and the severity of MR findings. Although severe early ARMD is associated with significant morbidity, mild disease is often stable for years. If patients with normal initial MR examinations develop ARMD, this usually occurs 7 years. A 1-year interval between MRI examinations is reasonable in asymptomatic patients. CONCLUSIONS: There is a general international consensus that ARMD is prevalent in symptomatic and asymptomatic patients with MOM THR and that while appearances vary with the type of prosthesis, there are characteristic features that make MARS MRI essential for diagnosis, staging and surveillance of the disease.

Metal ion levels not sufficient as a screening measure for adverse reactions in metal-on-metal hip arthroplasties.

This study aims to assess the accuracy of metal ion analysis in the diagnosis of adverse reaction to metal debris (ARMD) in patients with metal-on-metal hip arthroplasties by comparing the cobalt and chromium levels in 57 patients (62 hips) to findings on metal artifact reduction magnetic resonance imaging (MRI). An ARMD was detected using MRI in 18 (29%) of the hips. Forty patients had cobalt levels less than 7 µg/L, and 33 had chromium levels less than 7 µg/L, but 8 of these had an ARMD on MRI and only minimal symptoms (Oxford Hip Score ≥ 44/48). The incidence of ARMD was significantly higher when chromium concentration was above 7 µg/L (P = .02), but normal metal ion levels can be misleading and metal artifact reduction MRI imaging is advised in all patients.

Digital templating facilitates accurate leg length correction in total hip arthroplasty.

Digital templating of pre-operative radiographs is increasingly utilised by surgeons before total hip arthroplasty (THA) as part of an adequate preoperative preparation to minimise complications. Templating can accurately predict the required implant sizes but its use in facilitating correction of leg length discrepancy (LLD) has been underreported in the literature. We performed a retrospective analysis of a cohort of consecutive patients undergoing primary THA. A comparison was made of the implant sizes templated with actual sizes used. In addition, pre-operative leg-length discrepancy (LLD) was noted and compared with intra-operative measurement of LLD correction and post-operative LLD correction seen on postoperative radiographs, as measured by two independent observers. Statistical analysis was performed to investigate the correlation between pre- and postoperative measurements. Fifty nine patients that had primary THA were investigated, 42 with hybrid replacements, 17 with cemented replacements. Spearman's-rho 2-tailed correlation between templated and implanted femoral offset, stem size and acetabular cup size was 0.850, 0.709 and 0.834 respectively (p < 0.01 for all). Correlation between the pre-operative templated LLD and the measured post-operative corrected LLD was 0.841 (p < 0.01). No difference existed between hybrid and cemented hips or the presence or absence of a contralateral hip replacement. In this study, templating for THA was significantly accurate in predicting the required femoral and acetabular implant sizes. In addition, the correction of pre-operative LLD was accurately performed, as evidenced by measurement on post-operative films. The results of this study support the pre-operative digital templating of radiographs in total hip arthroplasty.

MRI of aseptic lymphocytic vasculitis-associated lesions in metal-on-metal hip replacements.

OBJECTIVE: The aim of this review is to describe the clinical, histopathologic, and MRI features of aseptic lymphocytic vasculitis-associated lesions in total hip replacements. CONCLUSION: The introduction of modern metal-on-metal hip arthroplasty has been accompanied by a newly described disease, aseptic lymphocytic vasculitis-associated lesions, which is characterized histologically by bland necrosis and dense perivascular lymphocytic infiltrates. Conventional radiographic findings are often normal, but the typical MRI findings include periprosthetic fluid collections, soft-tissue masses, gluteal tendon avulsion, bone loss, periosteal stripping, neurovascular involvement, and periprosthetic fractures. The severity of the histologic and MRI appearances can be graded according to defined published criteria.

The influence of obesity on early outcomes in primary hip arthroplasty.

Obesity is considered an independent risk factor for adverse outcome after arthroplasty surgery. Data on 191 consecutive total hip arthroplasties were prospectively collected. Body mass index (BMI) was calculated for each patient and grouped into nonobese (BMI <30 kg/m(2)), obese (BMI 30-34.9 kg/m(2)), and morbidly obese (BMI ≥35 kg/m(2)). Primary outcomes included functional improvement (Oxford hip score, 6-minute walk test and Short Form-12 Health Survey general health questionnaire) and postoperative complications. Subgroup analysis of surgeons' overall perception of operative technical difficulty was also performed. This study shows that total hip arthroplasties in obese patients were perceived, by the surgeon, to be significantly more difficult. However, this did not translate to an increased risk of complications, operation time, or blood loss, nor suboptimal implant placement. In addition, our results suggest that obese patients gain similar benefit from hip arthroplasty as do nonobese patients, but morbidly obese patients have significantly worse 6-minute walk test scores at 6 weeks.

A reliability study of measurement tools available on standard picture archiving and communication system workstations for the evaluation of hip radiographs following arthroplasty.

BACKGROUND: Conventional radiography is the primary imaging tool for routine follow-up of total hip replacements, but the reliability of this method has been questioned. The aim of this study was to assess the reliability of commonly used measurements of the position of hip prostheses on postoperative radiographs with use of tools available on all standard picture archiving and communication system workstations. METHODS: Fifty anteroposterior pelvic and lateral hip radiographs that were made after a unilateral total hip arthroplasty were included in this study. Acetabular inclination, lateral offset, lower-limb length, center of rotation, and femoral stem angle were independently assessed by two observers. Intraclass correlation coefficients were calculated for each measurement. RESULTS: The results demonstrated excellent reliability for acetabular angle (r = 0.95), lower-limb length (r = 0.91), and lateral offset (r = 0.95) measurements and good reliability for center of rotation (r = 0.73) and lateral femoral stem angle (r = 0.68) measurements. CONCLUSIONS: The position of total hip replacements can be reliably assessed with use of simple electronic tools and standard radiology workstations.

Reliability of the radiological assessments of radiolucency and loosening in total hip arthroplasty using PACS.

We evaluated the reliability of three commonly used radiological assessments of total hip arthroplasty (THA) using the electronic picture archiving and communications system (PACS). Thirty-three patients were selected at random at a mean of 7.2 years after THA. The Barrack, Gruen and Hodgkinson evaluations of cementing quality, loosening/radiolucency were graded. Three observers assessed each radiograph (one consultant orthopaedic surgeon, one senior orthopaedic registrar and one senior house officer). Four weeks after the initial assessment, each radiograph was reviewed a second time. The findings indicated that the intra- and inter-observer reliability of the Barrack, Gruen and Hodgkinson methods were questionable. Inter-observer reliability using the Gruen system was poor, using the Barrack system it was moderate to good, and fair to good using the Hodgkinson assessment. Intra-observer reliability was moderate to good for Barrack assessment, poor to good using Gruen zone assessments, but good to very good for the Hodgkinson assessment. The use of Barrack, Gruen and Hodgkinson assessments to evaluate femoral and acetabular loosening should be questioned since these exhibit limited inter- and intra-observer reliability on PACS radiographs, but of the three, the Hodgkinson system is the most reliable.

Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty.

BACKGROUND AND PURPOSE: Adverse reactions to metal debris have been reported to be a cause of pain in metal-on-metal hip arthroplasty. We assessed the incidence of both symptomatic and asymptomatic adverse reactions in a consecutive series of patients with a modern large-head metal-on-metal hip arthroplasty. METHODS: We studied the early clinical results and results of routine metal artifact-reduction MRI screening in a series of 79 large-head metal-on-metal hip arthroplasties (ASR; DePuy, Leeds, UK) in 68 patients. 75 hips were MRI scanned at mean 31 (12-52) months after surgery. RESULTS: 27 of 75 hips had MRI-detected metal debris-related abnormalities, of which 5 were mild, 18 moderate, and 4 severe. 8 of these hips have been revised, 6 of which were revised for an adverse reaction to metal debris, diagnosed preoperatively with MRI and confirmed histologically. The mean Oxford hip score (OHS) for the whole cohort was 21. It was mean 23 for patients with no MRI-based evidence of adverse reactions and 19 for those with adverse reactions detected by MRI. 6 of 12 patients with a best possible OHS of 12 had MRI-based evidence of an adverse reaction. INTERPRETATION: We have found a high early revision rate with a modern, large-head metal-on-metal hip arthroplasty. MRI-detected adverse rections to metal debris was common and often clinically "silent". We recommend that patients with this implant should be closely followed up and undergo routine metal artifact-reduction MRI screening.

Grading the severity of soft tissue changes associated with metal-on-metal hip replacements: reliability of an MR grading system.

INTRODUCTION: Metal-on-metal (MoM) soft tissue reactions or aseptic lymphocytic vasculitis-associated lesions (ALVAL) are being recognised using metal artefact reduction (MAR) MR with increasing frequency following the advent of second generation metal-on-metal bearings, but there is no standardised technique for reporting of MR appearances in this disease. The aim of this study was to measure the reliability of a grading system designed for scoring the severity of MoM disease on MRI. MATERIALS AND METHODS: MRI examinations of 73 hips in 59 patients were retrospectively selected and then anonymised, randomised and reviewed by three independent observers (musculoskeletal radiologists). Each MR examination was scored as either A: normal, B: infection, C1: mild MoM disease, C2: moderate MoM disease or C3: severe MoM disease according to pre-defined criteria. Kappa correlation statistics were used to compare the observations. RESULTS: There was substantial agreement among all three observers; the correlation coefficient between the two most experienced observers was κ = 0.78 [95% confidence intervals (CI): 0.68-0.88] and when compared with the least experienced observer coefficients were κ = 0.69 (95% CI: 0.57-0.80) and κ = 0.66 (95% CI: 0.54-0.78). The strongest correlation occurred for grades A, C2 and C3. The weakest correlations occurred for grades B and C1. CONCLUSION: The grading system described in this study is reliable for evaluating ALVAL in MoM prostheses using MR but is limited in differentiating mild disease from infection.

The natural history of metallosis from catastrophic failure of a polyethylene liner in a total hip.

We report on a case of metallosis initially presumed to be heterotopic ossification based on radiologic findings. A 68-year-old man with a total hip arthroplasty experienced failure of the polyethylene liner, resulting in articulation of the ceramic head with the titanium acetabular shell. During revision surgery, extensive metallic debris was evident macroscopically throughout the periprosthetic tissue and was confirmed histologically to be metallosis.