Patellar resurfacing and kneeling ability after total knee arthroplasty: a systematic review.

BACKGROUND: Difficulty kneeling following total knee arthroplasty (TKA) remains highly prevalent, and has cultural, social, and occupational implications. With no clear evidence of superiority, whether or not to resurface the patella remains debatable. This systematic review examined whether resurfacing the patella (PR) or not (NPR) influences kneeling ability following TKA. METHODS: This systematic review was conducted by following PRISMA guidelines. Three electronic databases were searched utilizing a search strategy developed with the aid of a department librarian. Study quality was assessed using MINROS criteria. Article screening, methodological quality assessment and data extraction were performed by two independent authors, and a third senior author was consulted if consensus was not reached. RESULTS: A total of 459 records were identified, with eight studies included in the final analysis, and all deemed to be level III evidence. The average MINORS score was 16.5 for comparative studies and 10.5 for non-comparative studies. The total number of patients was 24,342, with a mean age of 67.6 years. Kneeling ability was predominantly measured as a patient-reported outcome measure (PROM), with two studies also including an objective assessment. Two studies demonstrated a statistically significant link between PR and kneeling, with one demonstrating improved kneeling ability with PR and the other reporting the opposite. Other potential factors associated with kneeling included gender, postoperative flexion, and body mass index (BMI). Re-operation rates were significantly higher in the NPR cohort whereas PR cohorts had higher Feller scores, patient-reported limp and patellar apprehension. CONCLUSION: Despite its importance to patients, kneeling remains not only under-reported but also ill-defined in the literature, with no clear consensus regarding the optimum outcome assessment tool. Conflicting evidence remains as to whether PR influences kneeling ability, and to clarify the situation, large prospective randomized studies are required.

The use of pre-operative Inferior Vena Cava filters for thromboprophylaxis in ultra-high-risk patients undergoing total hip and knee arthroplasty: a systematic review and narrative analysis.

PURPOSE: Patients undergoing total hip (THA) or knee (TKA) arthroplasty are at high risk of venous thromboembolism (VTE). As the number performed annually increases, the population at risk of fatal pulmonary embolism (PE) also grows. Ultra-high-risk arthroplasty patients (UHRAPs) include those with additional comorbidities, or a history of VTE, for many of whom routine prophylaxis will previously have failed. Pre-operative insertion of Inferior Vena Cava filters (IVCFs) has been recommended for thromboprophylaxis in UHRAPs, and this review was performed to establish their results. METHODS: A systematic search of MEDLINE and Embase databases was performed for studies reporting the use of Inferior Vena Cava filters in hip and knee arthroplasty patients. RESULTS: Ten studies met the inclusion criteria, containing 718 IVCFs in Orthopaedic patients, 343 of which were permanent (47.8%), 369 potentially retrievable (51.4%), 5 absorbable (0.6%) and one of unknown design (0.1%). Patient age averaged 64.7yrs (17-95) and 56% were female. Pre-operatively, 415 prophylactic IVCFs were inserted in 409 UHRAPs, undergoing a total of 438 total joint arthroplasties (TJA). There were 11 cases of PE in the entire series (1.5%) only one of which was fatal (0.01%), with four non-fatal PE in the UHRAP group (0.96%). Removal was attempted for 283 of the retrievable filters (76.7%) and was successful in 280 (98.9%). CONCLUSION: The use of IVCFs eliminated fatal PE in UHRAPs, but larger, high-quality studies, with standardised reporting, are still required to determine their absolute indications for use, complication profile, efficacy and optimum design.

Is success written in the stars? The effect of zodiac sign on the outcome of total knee arthroplasty.

AIM: There are 12 signs of the zodiac, each attributed with its own specific personality traits, desires and attitudes. The aim of the study was to evaluate the effect of zodiac sign on patient-reported outcome measures (PROMS) following primary total knee arthroplasty (TKA). METHOD: Patients undergoing primary TKA during a 2-year period (January 2019 to December 2020) were identified retrospectively. Patient demographics, Oxford Knee Score (OKS), EuroQol 5-dimension (EQ-5D) (baseline, 1 and 2 years) and patient satisfaction scores (1 and 2 years) were collected. Each patient's zodiac sign was assigned from their date of birth. RESULTS: There were 509 patients (228 males [44.8%] and 281 females [55.2%]) with a mean age of 70.9 years and a mean BMI of 30.3. There were no significant differences in gender (p=0.712), age (p=0.088), BMI (p=0.660), or pre-operative OKS (p=0.539). Aries and Gemini (0.366) had the worst and Pisces the best (0.595) pre-operative EQ-5D scores (p=0.038). When adjusting for confounding, Aries (p=0.031) had a greater improvement in EQ-5D at 1 year, although this was not maintained at 2 years. When adjusting for confounding, Pisceans had significantly less of an improvement in OKS at both 1 (p=0.022) and 2 years (p=0.042) and also had a significantly lower risk of satisfaction at 2 years (odds ratio 0.41, p=0.043). CONCLUSION: Zodiac sign was associated with outcome following TKA. Pisceans had the best pre-operative EQ-5D scores, but the least improvement in the post-operative joint specific score (OKS) and were less likely to be satisfied, despite achieving an equal improvement in their health-related quality of life (EQ-5D). Aries started with the lowest pre-operative EQ-5D scores but achieved the best scores at 1 year. Our study shows that an individual's zodiac sign may serve as a useful predictive factor for functional outcomes and satisfaction following TKA. However, our findings are the result of multiple testing in a large dataset following a data trawl, and correlation does not necessarily equal causation even in a real-world registry.

Periprosthetic femoral fractures around the original cemented polished triple-tapered C-stem femoral implant: a consecutive series of 500 primary total hip arthroplasties with an average follow-up of 15 years.

INTRODUCTION: The true incidence of periprosthetic femoral fracture (PFF) around cemented polished taper-slip implants remains largely unknown. Registries usually only capture PFFs that result in revision, missing those managed non-operatively or treated by open reduction and internal fixation (ORIF). This study reports the long-term rate of PFF with the original triple-tapered C-stem femoral implant. MATERIALS AND METHODS: A prospective review of a consecutive series of 500 primary total hip arthroplasties (THAs) performed at a single centre between March 2000 and December 2005, with average follow-up of 15 years (12-19 years). RESULTS: There were 500 consecutive THAs in 455 patients. Seven PFFs (1.4%) occurred in seven patients at an average of 7.9 years (range 2-11.5) from the primary arthroplasty. Five PFFs were managed by ORIF, one Vancouver B3 fracture was revised for a loose implant and one patient was treated non-operatively. Average age at primary operation was 74 years (67-87) and BMI averaged 27.3 (22-31). There was no typical fracture pattern and no statistically significant associations with patient demographics (age, gender, BMI, diagnosis) or prosthetic details (size, offset, alignment, cement mantle, subsidence). Survivorship to the occurrence of PFF was 99% (97.3-99.6%) at 10 years and 97.8% (95.5-99.0%) at 15. CONCLUSION: A PFF rate of 1.4% at an average follow-up of 15 years represents the true incidence of PFF with the use of the original triple-tapered C-Stem femoral implant, similar to that of published Exeter series (1.85%) but lower than the CPT (3.3%).

The ethylene oxide sterilised Opera acetabular component demonstrates high rates of loosening and revision compared to the gamma irradiated Ogee cup: a cohort study demonstrating potential shortcomings of revision-based registry data.

AIMS: To evaluate the long-term clinical outcomes of 2 cemented ultra-high molecular weight polyethylene (UHMWPE) acetabular components, with the main difference between the 2 components being their method of sterilisation. PATIENTS AND METHODS: Data was collected prospectively on 352 consecutive total hip replacements, performed between March 2000 and July 2004, at a single centre. A posterior approach was used with a cemented C-Stem femoral component (DePuy, Warsaw, IN, USA) in all cases and either the Ogee (DePuy, Warsaw, IN, USA) or the Opera (Smith & Nephew, Memphis, TN, USA) acetabular implant. Patients were reviewed clinically and radiologically with a median 12-year follow-up (6-16 years). RESULTS: The risk of experiencing loosening was 90% lower for the Gamma irradiated implant (GII) group compared to the ethylene oxide sterilised implant (EOSI) group, which was statistically significant (p = 0.003), (HR 0.10; 95% CI, 0.02-0.45). The incidence of cup revision was also lower in the GII group (p = 0.029), but after adjustment for age, gender and BMI was not statistically significant (p = 0.104). 15-year survivorship with failure/loosening as an endpoint was 70.1% for the EOS implant and 92.9% for the GII (OR 4.99; CI 95%, 1.75-14.2) and with revision as an endpoint was 81.4% for the EOSI and 92.9% for the GII (OR 2.60; CI 95%, 0.87-7.75). CONCLUSIONS: We report increased rates of loosening, revision and failure for the EOSI compared to the GII at long-term follow-up. This may have been attributable to the different sterilisation methods used.

The outcomes of total hip arthroplasty in rapidly progressive osteoarthritis: a systematic review.

PURPOSE: Rapidly progressive osteoarthritis of the hip is an uncommon and poorly understood condition. No universal definition of RPOH exists, however, a loss of joint space of 2 mm or more per year or 50% or more in one year with no other cause can be classed as RPOH. Due to the rapid loss of joint space and associated bone loss, total hip arthroplasty is the only viable treatment option. The aim of this systematic review is to assess the outcomes of THA in RPOH. METHODS: A systematic search of Embase, Medline and CINAHL databases was performed for studies reporting on the outcomes of patients with RPOH as their primary diagnosis for undergoing THA. Patient demographics, surgical techniques, implant selection, blood loss, morbidity and mortality, length of stay and patient-reported outcomes were amongst the data collected. RESULTS: Eight studies were found to be eligible, reporting on the outcomes of 270 patients with a mean age of 71. The majority of patients (88.1%) were female and the mean Body Mass Index was 27.6 kg/m2. Six of the eight studies reported on the need for additional reconstructive devices and procedures including the use of acetabular roof augmentation, acetabular reinforcement devices and revision acetabular components. Two studies reported increased blood loss in RPOH patients compared with non-RPOH patients (945 ml vs. 578 ml and 473.9 g vs. 353.9 g, respectively). CONCLUSION: RPOH leads to significant pre-operative morbidity and THA for RPOH has been shown to result in greater blood loss, prolonged operative time and increased complexity of the procedure all of which result in increased cost. There is a paucity of data on the long-term outcomes for these patients and more well-constructed studies are therefore required.

The composition of cell-based therapies obtained from point-of-care devices/systems which mechanically dissociate lipoaspirate: a scoping review of the literature.

PURPOSE: Cell-based therapies using lipoaspirate are gaining popularity in orthopaedics due to their hypothesised regenerative potential. Several 'point-of-care' lipoaspirate-processing devices/systems have become available to isolate cells for therapeutic use, with published evidence reporting their clinical relevance. However, few studies have analysed the composition of their 'minimally-manipulated' cellular products in parallel, information that is vital to understand the mechanisms by which these therapies may be efficacious. This scoping review aimed to identify devices/systems using mechanical-only processing of lipoaspirate, the constituents of their cell-based therapies and where available, clinical outcomes. METHODS: PRISMA extension for scoping reviews guidelines were followed. MEDLINE, Embase and PubMed databases were systematically searched to identify relevant articles until 21st April 2022. Information relating to cellular composition and clinical outcomes for devices/systems was extracted. Further information was also obtained by individually searching the devices/systems in the PubMed database, Google search engine and contacting manufacturers. RESULTS: 2895 studies were screened and a total of 15 articles (11 = Level 5 evidence) fulfilled the inclusion criteria. 13 unique devices/systems were identified from included studies. All the studies reported cell concentration (cell number regardless of phenotype per millilitre of lipoaspirate) for their devices/systems (range 0.005-21 × 106). Ten reported cell viability (the measure of live cells- range 60-98%), 11 performed immuno-phenotypic analysis of the cell-subtypes and four investigated clinical outcomes of their cellular products. Only two studies reported all four of these parameters. CONCLUSION: When focussing on cell concentration, cell viability and MSC immuno-phenotypic analysis alone, the most effective manual devices/systems were ones using filtration and cutting/mincing. However, it was unclear whether high performance in these categories would translate to improved clinical outcomes. Due to the lack of standardisation and heterogeneity of the data, it was also not possible to draw any reliable conclusions and determine the role of these devices/systems in clinical practice at present. LEVEL OF EVIDENCE: Level V Therapeutic.

Artificial intelligence for image analysis in total hip and total knee arthroplasty : a scoping review.

AIMS: Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are common orthopaedic procedures requiring postoperative radiographs to confirm implant positioning and identify complications. Artificial intelligence (AI)-based image analysis has the potential to automate this postoperative surveillance. The aim of this study was to prepare a scoping review to investigate how AI is being used in the analysis of radiographs following THA and TKA, and how accurate these tools are. METHODS: The Embase, MEDLINE, and PubMed libraries were systematically searched to identify relevant articles. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews and Arksey and O'Malley framework were followed. Study quality was assessed using a modified Methodological Index for Non-Randomized Studies tool. AI performance was reported using either the area under the curve (AUC) or accuracy. RESULTS: Of the 455 studies identified, only 12 were suitable for inclusion. Nine reported implant identification and three described predicting risk of implant failure. Of the 12, three studies compared AI performance with orthopaedic surgeons. AI-based implant identification achieved AUC 0.992 to 1, and most algorithms reported an accuracy > 90%, using 550 to 320,000 training radiographs. AI prediction of dislocation risk post-THA, determined after five-year follow-up, was satisfactory (AUC 76.67; 8,500 training radiographs). Diagnosis of hip implant loosening was good (accuracy 88.3%; 420 training radiographs) and measurement of postoperative acetabular angles was comparable to humans (mean absolute difference 1.35° to 1.39°). However, 11 of the 12 studies had several methodological limitations introducing a high risk of bias. None of the studies were externally validated. CONCLUSION: These studies show that AI is promising. While it already has the ability to analyze images with significant precision, there is currently insufficient high-level evidence to support its widespread clinical use. Further research to design robust studies that follow standard reporting guidelines should be encouraged to develop AI models that could be easily translated into real-world conditions. Cite this article: Bone Joint J 2022;104-B(8):929-937.

Environmental sustainability in orthopaedic surgery : a scoping review.

AIMS: In the UK, the NHS generates an estimated 25 megatonnes of carbon dioxide equivalents (4% to 5% of the nation's total carbon emissions) and produces over 500,000 tonnes of waste annually. There is limited evidence demonstrating the principles of sustainability and its benefits within orthopaedic surgery. The primary aim of this study was to analyze the environmental impact of orthopaedic surgery and the environmentally sustainable initiatives undertaken to address this. The secondary aim of this study was to describe the barriers to making sustainable changes within orthopaedic surgery. METHODS: A literature search was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines through EMBASE, Medline, and PubMed libraries using two domains of terms: "orthopaedic surgery" and "environmental sustainability". RESULTS: A total of 13 studies were included in the final analysis. All papers studied the environmental impact of orthopaedic surgery in one of three areas: waste management, resource consumption, and carbon emissions. Waste segregation was a prevalent issue and described by nine studies, with up to 74.4% of hazardous waste being generated. Of this, six studies reported recycling waste and up to 43.9% of waste per procedure was recyclable. Large joint arthroplasties generated the highest amount of recyclable waste per procedure. Three studies investigated carbon emissions from intraoperative consumables, sterilization methods, and through the use of telemedicine. One study investigated water wastage and demonstrated that simple changes to practice can reduce water consumption by up to 63%. The two most common barriers to implementing environmentally sustainable changes identified across the studies was a lack of appropriate infrastructure and lack of education and training. CONCLUSION: Environmental sustainability in orthopaedic surgery is a growing area with a wide potential for meaningful change. Further research to cumulatively study the carbon footprint of orthopaedic surgery and the wider impact of environmentally sustainable changes is necessary.Cite this article: Bone Jt Open 2022;3(8):628-640.

Mapping analysis to predict the associated EuroQol five-dimension three-level utility values from the Oxford Knee Score : a prediction and validation study.

AIMS: The aims of this study were to assess mapping models to predict the three-level version of EuroQoL five-dimension utility index (EQ-5D-3L) from the Oxford Knee Score (OKS) and validate these before and after total knee arthroplasty (TKA). METHODS: A retrospective cohort of 5,857 patients was used to create the prediction models, and a second cohort of 721 patients from a different centre was used to validate the models, all of whom underwent TKA. Patient characteristics, BMI, OKS, and EQ-5D-3L were collected preoperatively and one year postoperatively. Generalized linear regression was used to formulate the prediction models. RESULTS: There were significant correlations between the OKS and EQ-5D-3L preoperatively (r = 0.68; p < 0.001) and postoperatively (r = 0.77; p < 0.001) and for the change in the scores (r = 0.61; p < 0.001). Three different models (preoperative, postoperative, and change) were created. There were no significant differences between the actual and predicted mean EQ-5D-3L utilities at any timepoint or for change in the scores (p > 0.090) in the validation cohort. There was a significant correlation between the actual and predicted EQ-5D-3L utilities preoperatively (r = 0.63; p < 0.001) and postoperatively (r = 0.77; p < 0.001) and for the change in the scores (r = 0.56; p < 0.001). Bland-Altman plots demonstrated that a lower utility was overestimated, and higher utility was underestimated. The individual predicted EQ-5D-3L that was within ± 0.05 and ± 0.010 (minimal clinically important difference (MCID)) of the actual EQ-5D-3L varied between 13% to 35% and 26% to 64%, respectively, according to timepoint assessed and change in the scores, but was not significantly different between the modelling and validation cohorts (p ≥ 0.148). CONCLUSION: The OKS can be used to estimate EQ-5D-3L. Predicted individual patient utility error beyond the MCID varied from one-third to two-thirds depending on timepoint assessed, but the mean for a cohort did not differ and could be employed for this purpose. Cite this article: Bone Jt Open 2022;3(7):573-581.

Post-operative peri-prosthetic fracture rates following the use of cemented polished taper-slip stems for primary total hip arthroplasty: a systematic review.

INTRODUCTION: Peri-prosthetic fractures (PPFs) are a serious complication of total hip arthroplasty (THA) associated with significant morbidity, mortality and re-operation similar to the rates seen following femoral neck fractures. When exploring the PPF rates around cemented stems, many studies combine the results of composite beam and taper-slip stems despite their different philosophies. This review looks specifically at PPFs with the use of cemented stems of the taper-slip philosophy to evaluate the demographics, PPF rate and fracture patterns in this patient cohort. MATERIALS AND METHODS: A systematic search of Embase, Medline and CINAHL databases was performed to seek studies involving the use of cemented, polished, taper-slip stems, reporting on a rate of post-operative PPF and not involving patient cohorts that were exclusively hip fracture or revision arthroplasty. RESULTS: 27 studies reported on 505 PPFs with an average time from primary operation to PPF of 71.2 months (2-301 months). The average age of patients who sustained PPFs was 70.6 years (53.5-82 years) and the majority were female (64.2%). The Vancouver B2 fracture type was most common (39.5%). Open reduction and internal fixation represented the management of choice in 61.2% of PPFs. There was a re-operation rate of 11.4%. CONCLUSION: This review suggests an association with being older and female, and a greater risk of PPFs secondary to low energy falls in cemented polished taper-slip stems.

Comparison of the accuracy of 2D and 3D templating methods for planning primary total hip replacement: a systematic review and meta-analysis.

There are advocates of both two-dimensional (2D) and three-dimensional (3D) templating methods for planning total hip replacement. The aim of this study was to compare the accuracy of implant size prediction when using 2D and 3D templating methods for total hip arthroplasty, as well as to compare the inter- and intra-observer reliability in order to determine whether currently available methods are sufficiently reliable and reproducible. Medline, EMBASE and PubMed were searched to identify studies that compared the accuracy of 2D and 3D templating for total hip replacement. Results were screened using the PRISMA flowchart and included studies were assessed for their level of evidence using the Oxford CEBM criteria. Non-randomized trials were critically appraised using the MINORS tool, whilst randomized trials were assessed using the CASP RCT checklist. A series of meta-analyses of the data for accuracy were also conducted. Ten studies reported that 3D templating is an accurate and reliable method of templating for total hip replacement. Six studies compared 3D templating with 2D templating, all of which concluded that 3D templating was more accurate, with three finding a statistically significant difference. The meta-analyses showed that 3D CT templating is the most accurate method. This review supports the hypothesis that 3D templating is an accurate and reliable method of preoperative planning, which is more accurate than 2D templating for predicting implant size. However, further research is needed to ascertain the significance of this improved accuracy and whether it will yield any clinical benefit.

The accuracy and reliability of preoperative digital 2D templating in prosthesis size prediction in uncemented versus cemented total hip arthroplasty: a systematic review and meta-analysis.

The purpose of this study was to compare the accuracy and the inter- and intra-observer reliability of preoperative digital 2D templating in prosthesis size prediction for the planning of cemented or uncemented THA.This study was registered in the NIHR PROSPERO database (ID: CRD42020216649) and conducted according to the PRISMA guidelines. A search of electronic databases in March 2021 found 29 papers overall. The quality of evidence was assessed using the IHE Quality Appraisal of Case Series Studies Checklist and the CASP Randomised Controlled Trials Checklist. A meta-analysis was conducted, and the accuracy was presented as proportions and the inter- and intra-observer reliability were measured using intraclass correlation coefficients (ICC).Accuracy within one prosthesis size (±1) for cemented stems was 0.89 (95% confidence interval (CI) 0.83-0.95), cemented cups 0.78 (95% CI 0.67-0.89), uncemented stems 0.74 (95% CI 0.66-0.82) and uncemented cups 0.73 (95% CI 0.67-0.79) (test of group differences: p = 0.010). Inter-observer reliability (ICC) for uncemented cups was 0.88 (95% CI 0.85-0.91), uncemented stems 0.86 (95% CI 0.81-0.91), cemented stems 0.69 (95% CI 0.54-0.84) and cemented cups 0.68 (95% CI 0.55-0.81) (test of group differences: p = 0.004). Due to lack of data, intra-observer reliability (ICC) could only be calculated for uncemented prostheses, which for the stems was 0.90 (95% CI 0.88-0.92) and for the cups was 0.87 (95% CI 0.83-0.90) (test of group differences: p = 0.124).The accuracy of preoperative digital templating is greater for cemented prostheses, but the inter-observer reliability is greater for uncemented prostheses. The intra-observer reliability showed a high level of agreement for uncemented prostheses. Cite this article: EFORT Open Rev 2021;6:1020-1039. DOI: 10.1302/2058-5241.6.210048.

Nickel hypersensitivity and skin patch testing in total hip replacement surgery: a systematic review.

Approximately 60,000 cemented femoral stems are implanted in the UK each year with the majority being manufactured from stainless steel containing 10-15% nickel. Nickel hypersensitivity has been reported in up to 13% of the general population and there is a concern that nickel hypersensitivity might adversely affect the outcome of total hip replacement (THR). We reviewed the current literature on the potential link between nickel hypersensitivity and THR complications, and the usefulness of patch testing.We conducted a literature search in PubMed, MEDLINE and EMBASE databases. The level of evidence and the quality of the selected studies were assessed using the Oxford Centre for Evidence-Based Medicine Criteria and the Methodological Index for Non-Randomised Studies tool, respectively.Twenty-six studies met the inclusion criteria, reporting on 1852 patients who underwent primary or revision THR. All studies detailed skin patch testing and recorded prevalence of nickel hypersensitivity from 1.5% to 33.3%. Five studies reported a rise in Nickel hypersensitivity following THR, while four reported a decreased prevalence post-operatively. Eight studies concluded that metal hypersensitivity could have developed following THR, while seven studies did not support a link between metal hypersensitivity and THR complications. Four of the studies recommended routine patch testing pre-operatively, but three others concluded that routine patch testing was not indicated.We have not identified a link between nickel hypersensitivity and THR complications, and the role of patch testing remains unclear. Further large-scale studies would be required to investigate this relationship and to clarify the role of patch testing in facilitating implant selection. Cite this article: EFORT Open Rev 2021;6:825-838. DOI: 10.1302/2058-5241.6.210051.

Temporal subsidence patterns of cemented polished taper-slip stems: a systematic review.

The literature was reviewed to establish the levels of stem subsidence for both double and triple-tapered implants in order to determine whether there were any differences in subsidence levels with regard to the methods of measurement, the magnitude and rate of subsidence and clinical outcomes.All studies reporting subsidence of polished taper-slip stems were identified. Patient demographics, implant design, radiological findings, details of surgical technique, methods of measurement and levels of subsidence were collected to investigate which factors were related to increased subsidence.Following application of inclusion and exclusion criteria, 28 papers of relevance were identified. The studies initially recruited 3090 hips with 2099 being available for radiological analysis at final follow-up. Patient age averaged 68 years (42-70), 60.4% were female and the average body mass index (BMI) was 27.4 kg/m2 (24.1-29.2).Mean subsidence at one, two, five and 10 years was 0.97 mm, 1.07 mm, 1.47 mm and 1.61 mm respectively. Although double-tapered stems subsided more than triple-tapered stems at all time points this was not statistically significant (p > 0.05), nor was the method of measurement used (p > 0.05).We report the levels of subsidence at which clinical outcomes and survivorship remain excellent, but based on the literature it was not possible to determine a threshold of subsidence beyond which failure was more likely.There were relatively few studies of triple-tapered stems, but given that there were no statistically significant differences, the levels presented in this review can be applied to both double and triple-tapered designs. Cite this article: EFORT Open Rev 2021;6:331-342. DOI: 10.1302/2058-5241.6.200086.

A rare case of arterial avulsion presenting with occult blood loss following total hip arthroplasty: a case report.

INTRODUCTION: Iatrogenic arterial damage during total hip replacement is a rare but potentially life- or limb-threatening complication. To the best of our knowledge, this is the first reported case of an avulsion injury to a posterior branch of the profunda femoral artery during primary hip arthroplasty. CASE PRESENTATION: We describe the case of a 55-year-old Caucasian man who underwent a total hip replacement. The patient's hemoglobin levels dropped postoperatively, but there was no obvious bleeding, hemodynamic instability, pulsatile mass, or limb ischemia. The patient's hemoglobin levels continued to drop despite nine units of transfused blood. Three days after surgery, the patient underwent an angiography that showed an avulsion injury to a posterior branch of the profunda femoral artery. The avulsion was ligated and the hematoma was evacuated. CONCLUSION: Vascular damage may present in many ways including obvious bleeding, haemodynamic instability, a pulsatile mass, limb ischemia, and occult blood loss. Any of these signs in isolation or in combination could represent a vascular injury and an urgent angiogram should be considered.

Smith-Petersen mould arthroplasty: an ultra-long-term follow-up.

We present a case of a Smith-Petersen mould arthroplasty in a 77-year-old man. The implant was inserted by Sir John Charnley himself in 1948. The patient is pain-free and walks without aids. At 56 years, this case represents the longest surviving Smith-Petersen mould arthroplasty with a satisfactory result in the current literature.

Intra-articular benign fibrous histiocytoma in the knee joint.

We report a rare case of benign fibrous histiocytoma presenting as an intra-articular tumor in the knee joint causing pain and limitation of movements. This is the first case reported with no attachment to tendinous or ligamentous structures.