Does size matter? Outcomes following revision total hip arthroplasty with long or primary stems: a systematic review and meta-analysis.

BACKGROUND: Femoral reconstruction with long stems is widely accepted as the standard in revision total hip arthroplasty (rTHA). However, long stems can be technically challenging to insert and can compromise bone stock for future revision. This study aimed to identify whether there was a difference in outcomes with using a long versus primary or short femoral stem in revision. METHODS: We performed a systematic review and meta-analysis of all articles comparing long and primary stem length in rTHA for Paprosky 1-3B femoral defects. The primary outcome measure was the reoperation rate after rTHA. Secondary outcomes included infection and dislocation rates, periprosthetic fracture, loosening, mortality, and patient-reported outcome measures (PROMs). RESULTS: The results of 3,102 rTHAs performed in 2,982 patients were reported from 9 eligible studies in the systematic review, of which 6 were included in the meta-analysis. The mean patient age was 67.4 and the mean follow-up lasted 5 years (range, 1-15 years). There was no significant difference in the reoperation rate (odds ratio 0.78; 95% confidence interval, 0.28-2.17, P = 0.63). Similarly, there was no significant difference in dislocation or periprosthetic fracture risk. Harris Hip Score was better with primary stems by a mean difference of 14.4 points (P < 0.05). Pooled 5-year stem-related survival was 91.3% ± 3.5% (SD) for primary stems and 89.9% ± 6.7% (SD) for long stems. CONCLUSIONS: A primary stem provided non-inferior outcomes compared with long stems in rTHA with Paprosky type 1-3B femoral defects. Primary stems may yield a more straightforward technique and preserve distal bone stock for future revision particularly in younger patients. In older patients with lower functional demands and who would benefit from a decreased risk of complications, a long cemented stem is recommended.

Does functional planning, 3D templating and patient-specific instrumentation improve accuracy in total hip replacement?- a randomized controlled trial.

AIMS: Debate continues as to the optimal orientation of the acetabular component in total hip arthroplasty (THA) and how to reliably achieve this. The primary objective of this study was to compare functional CT-based planning and patient-specific instruments with conventional THA using 2D templating. METHODS: A pragmatic single-center, patient-assessor blinded, randomized control trial of patients undergoing THA was performed. 54 patients (aged 18-70) were recruited to either Corin Optimized Positioning System (OPS) or conventional THA. All patients received a cementless acetabular component. All patients underwent pre- and postoperative CT scans, and four functional X-rays. Patients in the OPS group had a 3D surgical plan and bespoke guides made. Patients in the conventional group had a surgical plan based on 2D templating X-rays. The primary outcome measure was the mean error in acetabular anteversion as determined by postoperative CT scan. RESULTS: There was no statistically significant difference in the mean error in angle of acetabular anteversion when comparing OPS and conventional THA. In the OPS group, the achieved acetabular anteversion was within 10° of the planned anteversion in 96% of cases, compared with only 76% in the conventional group. The clinical outcomes were comparable between the groups. CONCLUSION: Large errors in acetabular orientation appear to be reduced when CT-based planning and patient-specific instruments are used compared to the standard technique but no significant differences were seen in the mean error.

Culture-negative periprosthetic joint infections.

Culture-negative periprosthetic joint infections (CN-PJI) pose a significant challenge in terms of diagnosis and management. The reported incidence of CN-PJI is reported to be between 7% and 15%.Fungi and mycobacterium are thought to be responsible for over 85% of such cases with more fastidious bacteria accounting for the rest.With the advent of polymerase chain reaction, mass spectrometry and next generation sequencing, identifying the causative organism(s) may become easier but such techniques are not readily available and are very costly.There are a number of more straightforward and relatively low-cost methods to help surgeons maximize the chances of diagnosing a PJI and identify the organisms responsible.This review article summarizes the main diagnostic tests currently available as well as providing a simple diagnostic clinical algorithm for CN-PJI. Cite this article: EFORT Open Rev 2019;4:585-594. DOI: 10.1302/2058-5241.4.180067.

Risk factors associated with revision for prosthetic joint infection following knee replacement: an observational cohort study from England and Wales.

BACKGROUND: Prosthetic joint infection is a devastating complication of knee replacement. The risk of developing a prosthetic joint infection is affected by patient, surgical, and health-care system factors. Existing evidence is limited by heterogeneity in populations studied, short follow-up, inadequate power, and does not differentiate early prosthetic joint infection, most likely related to the intervention, from late infection, more likely to occur due to haematogenous bacterial spread. We aimed to assess the overall and time-specific associations of these factors with the risk of revision due to prosthetic joint infection following primary knee replacement. METHODS: In this cohort study, we analysed primary knee replacements done between 2003 and 2013 in England and Wales and the procedures subsequently revised for prosthetic joint infection between 2003 and 2014. Data were obtained from the National Joint Registry linked to the Hospital Episode Statistics data in England and the Patient Episode Database for Wales. Each primary replacement was followed for a minimum of 12 months until the end of the observation period (Dec 31, 2014) or until the date of revision for prosthetic joint infection, revision for another indication, or death (whichever occurred first). We analysed the data using Poisson and piecewise exponential multilevel models to assess the associations between patient, surgical, and health-care system factors and risk of revision for prosthetic joint infection. FINDINGS: Of 679 010 primary knee replacements done between 2003 and 2013 in England and Wales, 3659 were subsequently revised for an indication of prosthetic joint infection between 2003 and 2014, after a median follow-up of 4·6 years (IQR 2·6-6·9). Male sex (rate ratio [RR] for male vs female patients 1·8 [95% CI 1·7-2·0]), younger age (RR for age ≥80 years vs <60 years 0·5 [0·4-0·6]), higher American Society of Anaesthesiologists [ASA] grade (RR for ASA grade 3-5 vs 1, 1·8 [1·6-2·1]), elevated body-mass index (BMI; RR for BMI ≥30 kg/m2vs <25 kg/m2 1·5 [1·3-1·6]), chronic pulmonary disease (RR 1·2 [1·1-1·3]), diabetes (RR 1·4 [1·2-1·5]), liver disease (RR 2·2 [1·6-2·9]), connective tissue and rheumatic diseases (RR 1·5 [1·3-1·7]), peripheral vascular disease (RR 1·4 [1·1-1·7]), surgery for trauma (RR 1·9 [1·4-2·6]), previous septic arthritis (RR 4·9 [2·7-7·6]) or inflammatory arthropathy (RR 1·4 [1·2-1·7]), operation under general anaesthesia (RR 1·1 [1·0-1·2]), requirement for tibial bone graft (RR 2·0 [1·3-2·7]), use of posterior stabilised fixed bearing prostheses (RR for posterior stabilised fixed bearing prostheses vs unconstrained fixed bearing prostheses 1·4 [1·3-1·5]) or constrained condylar prostheses (3·5 [2·5-4·7]) were associated with a higher risk of revision for prosthetic joint infection. However, uncemented total, patellofemoral, or unicondylar knee replacement (RR for uncemented vs cemented total knee replacement 0·7 [95% CI 0·6-0·8], RR for patellofemoral vs cemented total knee replacement 0·3 [0·2-0·5], and RR for unicondylar vs cemented total knee replacement 0·5 [0·5-0·6]) were associated with lower risk of revision for prosthetic joint infection. Most of these factors had time-specific effects, depending on the time period post-surgery. INTERPRETATION: We have identified several risk factors for revision for prosthetic joint infection following knee replacement. Some of these factors are modifiable, and the use of targeted interventions or strategies could lead to a reduced risk of revision for prosthetic joint infection. Non-modifiable factors and the time-specific nature of the effects we have observed will allow clinicians to appropriately counsel patients preoperatively and tailor follow-up regimens. FUNDING: National Institute for Health Research.

Comparison of hip function and quality of life of total hip arthroplasty and resurfacing arthroplasty in the treatment of young patients with arthritis of the hip joint at 5 years.

OBJECTIVE: To compare the medium-term clinical effectiveness of total hip arthroplasty and resurfacing arthroplasty. DESIGN: Single centre, two-arm, parallel group, assessor blinded, randomised controlled trial with 1:1 treatment allocation. SETTING: A large teaching hospital in England. PARTICIPANTS: 122 patients older than 18 years with severe arthritis of the hip joint, suitable for resurfacing arthroplasty of the hip. Patients were excluded if they were considered to be unable to adhere to trial procedures or complete questionnaires. INTERVENTIONS: Total hip arthroplasty (replacement of entire femoral head and neck); hip resurfacing arthroplasty (replacement of the articular surface of femoral head only, femoral neck remains intact). Both procedures replaced the articular surface of the acetabulum. OUTCOMES: The outcome measures were hip function assessed using the Oxford Hip Score (OHS) and health-related quality of life assessed using the EuroQol (EQ-5D). Patients were followed up annually for a minimum of 5 years. Outcome data were modelled using the generalised estimating equation methodology to explore temporal variations during follow-up. RESULTS: 60 patients were randomly assigned to hip resurfacing arthroplasty and 62 to total hip arthroplasty. 95 (78%) of the 122 original study participants provided data at 5 years. There was a small decrease in both hip functions and quality of life in both groups of patients each year during the 5-year follow-up period. However, there was no evidence of a significant difference between treatments group in the OHS (P=0.333) or the EQ-5D (P=0.501). CONCLUSIONS: We previously reported no difference in outcome in the first year after surgery. The current medium-term results also show no evidence of a difference in hip function or health-related quality of life in the 5 years following a total hip arthroplasty versus resurfacing arthroplasty. TRIAL REGISTRATION NUMBER: ISRCTN33354155. UKCRN 4093.

Investigation of Taper Failure in a Contemporary Metal-on-Metal Hip Arthroplasty System Through Examination of Unused and Explanted Prostheses.

BACKGROUND: Large-diameter (≥36-mm) metal-on-metal (MoM) total hip replacements have been shown to fail at an unacceptably high rate. Globally, the DePuy Pinnacle prosthesis was the most widely used device of this type. There is evidence to suggest that one of the main reasons for the poor clinical performance of large-diameter MoM prostheses is the metal debris released from the head-stem taper junction-i.e., taper junction failure. The aim of this study was to investigate variation in the as-manufactured finish of the female taper surface and to determine its influence on material loss. We hypothesized that rougher surfaces with higher relative material peaks would be significantly associated with greater taper wear rates. METHODS: We analyzed 93 Articul/eze femoral head tapers with a 36-mm bearing diameter that had been used in combination with a Corail titanium uncemented stem. The influence of the surface topography of the as-manufactured female taper surface on taper wear was examined by means of a multiple regression model, taking into account other known variables. RESULTS: We identified great variation in the as-manufactured surface finish of the female taper surface, with a range of measured Ra values from 0.14 to 4.20 µm. The roughness of the female taper surface appeared to be the most important variable associated with taper wear (p < 0.001). The best-fitting regression model, including duration in vivo, head offset, reduced peak height (Rpk) value, stem shaft angle, and bearing surface wear rate, explained approximately 44% of the variation in taper wear rates. CONCLUSIONS: We concluded that the roughness of the female taper surface appears to be a significant factor in metal debris release from head-stem taper junctions. CLINICAL RELEVANCE: This study shows evidence that previously unappreciated variations in manufacturing processes may have a major impact on the clinical outcomes of patients.

Does intraoperative tissue sample enrichment help or hinder the identification of microorganisms in prosthetic joint infection?

OBJECTIVES: Biofilm formation reduces the efficacy of standard microbiological techniques in prosthetic joint infection. This study aimed to investigate the sensitivity, specificity and predictive values of tissue sample enrichment as a means to increase diagnostic yield. METHODS: Patients undergoing revision arthroplasty surgery between May 2004 and January 2013 had intraoperative tissue samples cultured in standard media as well as enriched in brain heart infusion broth. Patients were separated into infected or non-infected groups according to modified criteria from the Musculoskeletal Infection Society. RESULTS: A total of 197 revision arthroplasties were included (non-infected, n = 165; proven infection, n = 32). The mean time until revision in non-infected and infected groups was 75.9 and 41.7 months, respectively. The commonest microorganisms cultured were coagulase-negative staphylococci (42.9 %) and Staphylococcus aureus (34.4 %). The sensitivity and specificity of standard tissue culture were 0.25 (CI 0.18-0.33) and 0.98 (CI 0.95-0.99), respectively. Including enrichment culture results increased the sensitivity to 0.45 (CI 0.37-0.54), but decreased specificity to 0.59 (CI 0.52-0.66). CONCLUSION: Any potential increase in the sensitivity is far outweighed by the extremely high false-positive rate. Results of tissue samples cultured by enrichment should be used with caution and may lead to a worse outcome if incorrectly interpreted.

A case series of 35 hip revisions for adverse reactions to metal debris following Cormet hip resurfacing.

The primary aim of this study was to analyse our painful metal-on-metal (MoM) hip resurfacing revisions with evidence of 'adverse reactions to metal debris' (ARMD). In our series of 35 revisions the median whole blood Cobalt levels were 58 nmols/l (range 12-1407 nmols/l), and whole blood Chromium levels were 73 nmols/l (range 2-353 nmols/l). Thirty-four of our 35 patients had abnormal imaging on Ultrasound scanning (USS). The mean histological Campbell grading of ARMD was 4, and ranged from 0-9. The mean Oxford Hip Score (OHS) increased from 19 pre-revision (range 4-46) to 33 post-revision surgery (range 23-47).We found no correlation between the preoperative metal ion levels, and the severity of the disease or the outcome.Pain following hip resurfacing may arise from a number of causes and when groin pain arises in conjunction with abnormal cross sectional imaging we have offered our patients revision surgery regardless of raised metal ions or grossly abnormal imaging, with good results.

Sensitivities, specificities, and predictive values of microbiological culture techniques for the diagnosis of prosthetic joint infection.

BACKGROUND: Identifying the microorganism in a prosthetic joint infection is the key to appropriately targeting antimicrobial treatment. Despite the availability of various techniques, no single test is considered the definitive gold standard. AIM: Our aim was to determine the sensitivity, specificity, and positive/negative predictive values for a variety of culture techniques. METHODS: We performed a retrospective case series of 219 patients undergoing revision surgery of their hip or knee replacement between May 2004 and February 2013. The patients were classified as either infected or noninfected according to criteria set out by the Musculoskeletal Infection Society. The number and type of samples taken intraoperatively varied between cases but included tissue samples and fluid sent in either blood culture vials or sterile containers. RESULTS: The highest sensitivity was found with blood culture vials (0.85) compared to fluid in sterile containers (0.26) and tissues samples (0.32). Blood culture vials also had a better specificity and positive and negative predictive values profile. CONCLUSION: We conclude that, of the techniques studied, fluid in blood culture vials had the best profile for the correct identification of microorganisms and advocate its use.

A systematic review of the evidence for single stage and two stage revision of infected knee replacement.

BACKGROUND: Periprosthetic infection about the knee is a devastating complication that may affect between 1% and 5% of knee replacement. With over 79 000 knee replacements being implanted each year in the UK, periprosthetic infection (PJI) is set to become an important burden of disease and cost to the healthcare economy. One of the important controversies in treatment of PJI is whether a single stage revision operation is superior to a two-stage procedure. This study sought to systematically evaluate the published evidence to determine which technique had lowest reinfection rates. METHODS: A systematic review of the literature was undertaken using the MEDLINE and EMBASE databases with the aim to identify existing studies that present the outcomes of each surgical technique. Reinfection rate was the primary outcome measure. Studies of specific subsets of patients such as resistant organisms were excluded. RESULTS: 63 studies were identified that met the inclusion criteria. The majority of which (58) were reports of two-stage revision. Reinfection rated varied between 0% and 41% in two-stage studies, and 0% and 11% in single stage studies. No clinical trials were identified and the majority of studies were observational studies. CONCLUSIONS: Evidence for both one-stage and two-stage revision is largely of low quality. The evidence basis for two-stage revision is significantly larger, and further work into direct comparison between the two techniques should be undertaken as a priority.

A comparison of complications requiring return to theatre in hip and knee arthroplasty patients taking enoxaparin versus rivaroxaban for thromboprophylaxis.

BACKGROUND: There is no consensus on the optimal form of venous thromboembolic prophylaxis treatment in hip and knee arthroplasty patients, or on the safety and complication profile of the available chemical prophylaxis modalities. In this study we aimed to measure the return to theatre rate for any cause related to wound complications in patients undergoing total hip replacement and total knee replacement, and compare these rates between patients on oral Rivaroxaban 10mg OD and subcutaneous Enoxaparin 40mg OD in our department. MATERIAL AND METHODS: There were a total of 387 patients included in the study; 227 patients in group 1, who received Enoxaparin 40mg OD, and 160 patients in group 2, who received Rivaroxaban 10mg OD. RESULTS: The primary outcome measure was re-operation rate due to wound complications. Secondary outcome measures were infection rate, incidence of deep vein thrombosis, pulmonary emboli, duration of hospital stay, change in haemoglobin and haematocrit and blood transfusion rate. In this retrospective cohort study we found that patients who received Rivaroxaban were more than twice as likely to return to theatre for wound complications compared to patients receiving Enoxaparin. Although not statistically significant, this increase is in line with previous studies. Infection rates increased from 0.9% to 1.9% after the introduction of Rivaroxaban and microbiologically confirmed superficial infections rose from 1.3% to 3.1% after Rivaroxaban was introduced in our unit. These rises were not statistically significant. CONCLUSION: Our study highlights the need for large randomised controlled trials to assess post-operative complications following the introduction of Rivaroxaban for post-arthroplasty thromboprophylaxis.

Assessment of cup orientation in hip resurfacing: a comparison of TraumaCad and computed tomography.

PURPOSE: The orientation of the acetabular component in metal-on-metal hip resurfacing arthroplasty affects wear rate and hence failure. This study aimed to establish if interpretation of pelvic radiographs with TraumaCad software can provide a reliable alternative to CT in measuring the acetabular inclination and version. METHODS: TraumaCad was used to measure the acetabular orientation on AP pelvis radiographs of 14 painful hip resurfacings. Four orthopaedic surgeons performed each measurement twice. These were compared with measurements taken from CT reformats. The correlation between TraumaCad and CT was calculated, as was the intra- and inter-observer reliability of TraumaCad. RESULTS: There is strong correlation between the two techniques for the measurement of inclination and version (p <0.001). Intra- and inter-observer reliability of TraumaCad measurements are good (p <0.001). Mean absolute error for measurement of inclination was 2.1°. TraumaCad underestimated version compared to CT in 93% of cases, by 12.6 degrees on average. CONCLUSIONS: When assessing acetabular orientation in hip resurfacing, the orthopaedic surgeon may use TraumaCad in the knowledge that it correlates well with CT and has good intra- and inter-observer reliability but underestimates version by 12° on average.

Total hip arthroplasty versus resurfacing arthroplasty in the treatment of patients with arthritis of the hip joint: single centre, parallel group, assessor blinded, randomised controlled trial.

OBJECTIVES: To compare the clinical and cost effectiveness of total hip arthroplasty with resurfacing arthroplasty in patients with severe arthritis of the hip. DESIGN: Single centre, two arm, parallel group, assessor blinded, randomised controlled trial with 1:1 treatment allocation. SETTING: One large teaching hospital in the United Kingdom. PARTICIPANTS: 126 patients older than 18 years with severe arthritis of the hip joint, suitable for resurfacing arthroplasty of the hip. Patients were excluded if they were considered to be unable to adhere to trial procedures or complete questionnaires. INTERVENTIONS: Total hip arthroplasty (replacement of entire femoral head and neck); hip resurfacing arthroplasty (replacement of the articular surface of femoral head only, femoral neck remains intact). Both procedures replaced the articular surface of the acetabulum. MAIN OUTCOME MEASURES: Hip function at 12 months after surgery, assessed using the Oxford hip score and Harris hip score. Secondary outcomes were quality of life, disability rating, physical activity level, complications, and cost effectiveness. RESULTS: 60 patients were randomly assigned to hip resurfacing arthroplasty and 66 to total hip arthroplasty. Intention to treat analysis showed no evidence for a difference in hip function between treatment groups at 12 months (t test, P=0.242 and P=0.070 for Oxford hip score and Harris hip score, respectively); 95% of follow-up data was available for analysis. Mean Oxford hip score was 40.4 (95% confidence interval 37.9 to 42.9) in the resurfacing group and 38.2 (35.3 to 41.0) in the total arthroplasty group (estimated treatment effect size 2.23 (-1.52 to 5.98)). Mean Harris hip score was 88.4 (84.4 to 92.4) in the resurfacing group and 82.3 (77.2 to 87.5) in the total arthroplasty group (6.04 (-0.51 to 12.58)). Although we saw no evidence of a difference, we cannot definitively exclude clinically meaningful differences in hip function in the short term. Overall complication rates did not differ between treatment groups (P=0.291). However, we saw more wound complications in the total arthroplasty group (P=0.056) and more thromboembolic events in the resurfacing group (P=0.049). CONCLUSIONS: No evidence of a difference in hip function was seen in patients with severe arthritis of the hip, one year after receiving a total hip arthroplasty versus resurfacing arthroplasty. The long term effects of these interventions remain uncertain. TRIAL REGISTRATION: Current Controlled Trials ISRCTN33354155, UKCRN 4093.

The diagnostic accuracy of magnetic resonance imaging and ultrasonography in gluteal tendon tears--a systematic review.

Gluteal tendon tears are one of the many pathologies causing pain around the greater trochanter that are often labelled as trochanteric bursitis. We systematically reviewed the peer-reviewed literature to establish the accuracy of magnetic resonance imaging and ultrasonography in the diagnosis of gluteal tendon tears in patients with persistent lateral hip pain or Greater Trochanteric Pain Syndrome (GTPS). 7 studies met the inclusion criteria, comparing either imaging modality with a reference standard of surgical findings. Included studies were assessed for methodological quality using the QUADAS checklist. MRI had sensitivity of 33-100%, specificity of 92-100%, positive predictive value of 71-100% and negative predictive value of 50%. False-positives were common. High signal located superior to the trochanter had a stronger association with tears. Ultrasonography had a sensitivity of 79-100% and positive predictive value of 95-100%. The amount and quality of literature on the subject is limited and further well-designed studies are required to establish the optimum diagnostic strategy in this condition. Ultrasonography may prove to be the investigation of choice, despite requiring a skilled practitioner. The orthopaedic surgeon should liaise with an experienced musculoskeletal radiologist to best investigate and diagnose gluteal tendon tears in the clinical picture of GTPS.

Groin pain following hip resurfacing: a case-control study.

We compared 47 patients with groin pain following hip resurfacing to a matched control group. Functional scores and plain radiographs were assessed along with measurement of whole blood cobalt and chromium by inductively coupled mass spectrometry. Symptomatic patients underwent ultrasound scan of the affected hip. Mean functional outcomes were poor in those with pain and good in the control group. Groin pain was associated with valgus stem positioning and lower neck:head ratio (relatively narrow neck) (p=0.03, p=0.04 respectively). We classified patients with groin pain into two groups: biological and mechanical. The biological group had soft tissue abnormalities on USS and higher levels of cobalt and chromium (p=0.04, p=0.05 respectively). The mechanical group had normal USS, lower metal ion levels and more retroverted femoral components (p=0.01).

Femoral neck narrowing following hip resurfacing using posterior and Ganz approaches at two years.

We report a retrospective review of femoral head/neck ratios on post-operative and two year follow-up radiographs following hip resurfacing arthroplasty. The patients were in two matched groups, having had surgery through a posterior approach or via a Ganz trochanteric flip. There was no significant difference in femoral neck narrowing at follow up between the two surgical approaches. However, we found significant narrowing of the femoral neck in both groups by the time of the two year follow-up radiograph.

Total hip replacement in an adolescent patient with harlequin ichthyosis; a case report.

Harlequin ichthyosis (HI) is a rare autosomal recessive skin disorder. No orthopaedic procedure has previously been described on a patient with HI. We report the case of a 17-year-old patient with HI who presented with bilateral juvenile idiopathic arthritis of the hips who underwent bilateral total hip replacements. Our standard operative and postoperative regime was followed and no complications occurred. One year after the second procedure our patient had a Oxford hip score of 43 and was very satisfied with the result.

Metal-on-metal hip resurfacing with uncemented fixation of the femoral component. A minimum 2 year follow up.

The current generation of metal-on-metal hip resurfacing designs has largely been characterized by cemented femoral fixation using a cementless cup. We present the clinical results of 135 entirely uncemented metal-on-metal hip resurfacing procedures. The primary outcome measures were revision for any cause and the Oxford hip score at the latest follow up. The average length of followup was 2.9 years. The mean Oxford hip score was 18.4 and no patient required revision of either component during the study period. Uncemented femoral fixation may be comparable to fixation with cement in metal-on-metal hip resurfacing.