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Cementless total knee arthroplasty (TKA) is the subject of renewed interest. Previous concerns about survivorship have been addressed and there is an appeal in terms of biological fixation and surgical efficiency. However, even surgeon advocates have concerns about the risk of marked subsidence when using this technology in older patients at risk for osteoporosis.This was a retrospective analysis of 1,000 consecutive fully cementless mobile bearing TKAs performed at a single institution on women over 75 years of age who had postoperative and 1-year x-rays. The primary outcome was the incidence of subsidence.There were three asymptomatic cases with definite subsidence and change in alignment. In a fourth symptomatic case, the femoral component subsided into varus and the tibia into valgus, thus maintaining alignment which facilitated nonoperative treatment in a 92-year-old. Overall, at 1 year, there were two- liner revisions for infection without recurrence. Five patients had further surgery, of which three were washouts and two were for periprosthetic fractures sustained postoperatively within 1 year. Seven patients had further anesthesia, of which five were manipulations and two were nonrecurrent closed reductions for spinouts.Cementless TKA did not have a high risk of subsidence in this at-risk population. In the hands of experienced surgeons, these procedures can be used safely irrespective of bone quality.

The risk factors for and clinical impact of radiolucent lines (RLLs) in cementless total hip arthroplasty remain contentious. The aim of this work was to describe a method of classification that has clinical significance and to identify risk factors.A cohort of 288 subjects with unrevised Corail stems (DePuy Synthes, Warsaw, IN) were reviewed with radiographs and Oxford Hip Scores at 10 years. Based on clinical experience, three groups were defined; those with no RLLs (NoRLLs), those considered to have benign RLLs (BenRLLs), and those considered to have significant RLLs (SigRLLs). SigRLLs were then compared to BenRLLs and NoRLLs to determine the validity of this classification.One hundred and nine (37.8%) had NoRLLs, 111 (38.5%) had BenRLLs, and 68 (23.6%) had SigRLLs. No significant difference apart from gender was noted between the occurrence of BenRLLs and NoRLLs after multinomial regression analysis, consequently the NoRLLs and BenRLLs groups were combined (NoSigRLLs) and compared to SigRLLs. Non-cross-linked polyethylene (odds ratio = 4.6, P.001), collarless stem design (odds ratio = 9.4, P.001), undersizing (odds ratio = 1.2, P = .028), and male sex (odds ratio = 2.1, P = .008) were risk factors for SigRLLs. Regression analysis also revealed that increasing age at operation decreased the likelihood of SigRLLs (P.001). Patients with SigRLLs had significantly higher pain scores (P = .005) although overall Oxford Hip Scores were not significantly different (P = .364).The definition of SigRLLs proposed in this study was significantly associated with that of non-cross-linked polyethylene, absence of a collar, undersizing, and higher pain scores.

Aims The aim of this study is to assess the impact of a pilot enhanced recovery after surgery (ERAS) programme on length of stay (LOS) and post-discharge resource usage via service evaluation and cost analysis. Methods Between May and December 2019, 100 patients requiring hip or knee arthroplasty were enrolled with the intention that each would have a preadmission discharge plan, a preoperative education class with nominated helper, a day of surgery admission and mobilization, a day one discharge, and access to a 24/7 dedicated helpline. Each was matched with a patient under the pre-existing pathway from the previous year. Results Mean LOS for ERAS patients was 1.59 days (95% confidence interval (CI) 1.14 to 2.04), significantly less than that of the matched cohort (3.01 days; 95% CI 2.56 to 3.46). There were no significant differences in readmission rates for ERAS patients at both 30 and 90 days (six vs four readmissions at 30 days, and nine vs four at 90 days). Despite matching, there were significantly more American Society of Anesthesiologists (ASA) grade 3 patients in the ERAS cohort. There was a mean cost saving of £757.26 (95% CI £-1,200.96 to £-313.56) per patient. This is despite small increases in postoperative resource usage in the ERAS patients. Conclusion ERAS represents a safe and effective means of reducing LOS in primary joint arthroplasty patients. Implementation of ERAS principles has potential financial savings and could increase patient throughput without compromising care. In elective care, a preadmission discharge plan is key. Cite this article: Bone Jt Open 2021;2(11):966–973.

Background: Achieving accurate and consistent acetabular component orientation remains a major challenge in total hip arthroplasty. Methods: We used a pelvic model to compare freehand techniques vs mechanical and anatomical alignment guides in achieving a target operative inclination (OI) and operative anteversion (OA). Thirty subjects comprising consultant orthopedic surgeons, orthopedic trainees, and nonsurgical staff positioned an acetabular component in a pelvic model using 3 different methods for guiding inclination and another 3 for guiding version. Results: Using either a standard mechanical alignment guide (MAG) or a spirit level MAG technique eliminated outliers from target OI, while the freehand method resulted in 46.7% of measurements outside the OI target range. The spirit level MAG technique significantly outperformed the standard MAG technique in median unsigned deviation from target OI (0.8° vs 2.1°, P < .001). Either method of referencing the transverse acetabular ligament for version yielded lower deviations from target OA than the freehand method and fewer outliers from the ±5° target range. Surgical experience was not a significant factor for accurately achieving target OI and OA. Conclusions: Even in an idealized in vitro model, a wide range of OI and OA is seen with the freehand technique of cup placement by subjects of all levels of surgical experience. Using either a standard MAG or a spirit level MAG reduces deviations in target OI, with the spirit level MAG method yielding the best accuracy. Using the transverse acetabular ligament to guide cup anteversion yields more accurate OA.

Aims We studied the outcomes of hip and knee arthroplasties in a high-volume arthroplasty centre to determine if patients with morbid obesity (BMI ≥ 40 kg/m2) had unacceptably worse outcomes as compared to those with BMI < 40 kg/m2. Methods In a two-year period, 4,711 patients had either total hip arthroplasty (THA; n = 2,370), total knee arthroplasty (TKA; n = 2,109), or unicompartmental knee arthroplasty (UKA; n = 232). Of these patients, 392 (8.3%) had morbid obesity. We compared duration of operation, anaesthetic time, length of stay (LOS), LOS > three days, out of hours attendance, emergency department attendance, readmission to hospital, return to theatre, and venous thromboembolism up to 90 days. Readmission for wound infection was recorded to one year. Oxford scores were recorded preoperatively and at one year postoperatively. Results On average, the morbidly obese had longer operating times (63 vs 58 minutes), longer anaesthetic times (31 vs 28 minutes), increased LOS (3.7 vs 3.5 days), and significantly more readmissions for wound infection (1.0% vs 0.3%). There were no statistically significant differences in either suspected or confirmed venous thromboembolism. Improvement in Oxford scores were equivalent. Conclusion Although morbidly obese patients had less favourable outcomes, we do not feel that the magnitude of difference is clinically significant when applied to an individual, particularly when improvement in Oxford scores were unrelated to BMI. Cite this article: Bone Jt Open 2021;2(7):515–521.

With respect to survivorship following total knee arthroplasty (TKA), joint registries consistently demonstrate higher revision rates for both sexes in those less than 55 years of age. The current study analyzed the survivorship of 500 cementless TKAs performed in this age group in a high-volume primary joint unit where cementless TKA has traditionally been used for the majority of patients.This was a retrospective review of 500 consecutive TKAs performed in patients under the age of 55 years between March 1994 and April 2017. The primary outcome measures for the study were survivorship and all-cause revisions. Secondary outcome measures included non-revision procedures, clinical, functional, and radiological outcomes.An all-cause survival rate of 98.4% and an aseptic survival rate of 99.2% at a median time of 10.7 years (IQR 7.3-14.9, Range 0.2-27.7) was found. Four patents were revised for infection, 2 for stiffness, 1 for aseptic loosening of the tibial component, and 1 for a patella that was resurfaced for anterior knee pain. Thirty-four patients (6.8%) had a non-revision procedure with manipulation under anesthetic (MUA) accounting for 27. On multivariate analysis, pre-operative ROM and female gender were negatively associated with postoperative range of motion (p0.001 and p=0.003, respectively). Sixty-seven patients (17.3%) had RLL's and on multivariate analysis, there were no significant predictors of radiolucent lines.Cementless TKA in the young patient can achieve excellent clinical and functional outcomes. At a median of 10.7 years, aseptic revision rates are exceptionally low at 0.8% for the entire cohort.

Delirium is an acute change in attention and cognition occurring in ~65% of severe SARS-CoV-2 cases. It is also common following surgery and an indicator of brain vulnerability and risk for the development of dementia. In this work we analyzed the underlying role of metabolism in delirium-susceptibility in the postoperative setting using metabolomic profiling of cerebrospinal fluid and blood taken from the same patients prior to planned orthopaedic surgery. Distance correlation analysis and Random Forest (RF) feature selection were used to determine changes in metabolic networks. We found significant concentration 2 differences in several amino acids, acylcarnitines and polyamines linking delirium-prone patients to known factors in Alzheimer’s disease such as monoamine oxidase B (MAOB) protein. Subsequent computational structural comparison between MAOB and angiotensin converting enzyme 2 as well as protein-protein docking analysis showed that there potentially is strong binding of SARS-CoV-2 spike protein to MAOB. The possibility that SARS-CoV-2 influences MAOB activity leading to the observed neurological and platelet-based complications of SARS-CoV-2 infection requires further investigation.

Patients and methods: We present the data on 8606 total hip arthroplasty (THA) procedures carried out in 7818 patients through a posterior approach between 1998 and 2017. Results: 218 hips (2.5%) suffered at least 1 dislocation with dislocation rates declining from 6.2% from 1998 to 2002 to 1.5% from 2003 to 2017. Overall, 92 hips (1.06%) required revision surgery but of these, only 5 (0.06%) had a full revision of both components with the remaining 87 requiring intervention only on the acetabular side. None have had a pseudo-arthrosis; none were left dislocated and all remain stable to date. Conclusions: In patients who have a second dislocation within 3 months of their primary surgery we recommend a spica or long leg cylinder cast to reduce the need for revision surgery. We propose an algorithm to manage instability with less aggressive operative treatment in this often-elderly patient population with the potential for less physiological insult and significant cost savings.

Introduction The enhanced recovery after surgery (ERAS) concept in arthroplasty surgery has led to a reduction in postoperative length of stay in recent years. Patients with prolonged length of stay (PLOS) add to the burden of a strained NHS. Our aim was to identify the main reasons. Methods A PLOS was arbitrarily defined as an inpatient hospital stay of four days or longer from admission date. A total of 2,000 consecutive arthroplasty patients between September 2017 and July 2018 were reviewed. Of these, 1,878 patients were included after exclusion criteria were applied. Notes for 524 PLOS patients were audited to determine predominant reasons for PLOS. Results The mean total length of stay was 4 days (1 to 42). The top three reasons for PLOS were social services, day-before-surgery admission, and slow to mobilize. Social services accounted for 1,224 excess bed days, almost half (49.2%, 1,224/2,489) of the sum of excess bed days. Conclusion A preadmission discharge plan, plus day of surgery admission and mobilization on the day of surgery, would have the potential to significantly reduce length of stay without compromising patient care. Cite this article: Bone Joint Open 2020;1-8:488–493.

Background Following concerns regarding the emergence of Clostridium difficile infection in 2010, we changed antibiotic prophylaxis in patients undergoing primary hip and knee arthroplasty from cefuroxime to flucloxacillin and single-dose (SD) gentamicin. A subsequent perceived increase in the incidence of post-operative acute kidney injury (AKI) led us to evaluate the AKI incidence between different prophylactic antibiotic regimes used at our centre. Methods We examined the incidence of AKI as defined by Kidney Disease: Improving Global Outcomes criteria in 1588 patients undergoing primary hip or knee arthroplasty from January 2010 to January 2015. Patients received the following prophylactic antibiotic regimes: 8 g flucloxacillin in four divided doses and SD gentamicin 1.5 mg/kg ideal body weight (IBW; maximum dose 120 mg; n = 400), 8 g flucloxacillin alone in four divided doses (n = 400), SD cefuroxime (n = 400), triple-dose (TD) cefuroxime (n = 188) and teicoplanin with SD gentamicin 1.5 mg/kg IBW (n = 200). Results The incidence of AKI was as follows: flucloxacillin and gentamicin (13%); flucloxacillin alone (8.5%); SD cefuroxime (2%); TD cefuroxime (0.5%); and teicoplanin and gentamicin (3%). Of the six patients who developed Stage 3 AKI, all were in the flucloxacillin and gentamicin group. The odds ratio for the development of AKI derived from a binary logistic regression model was highest in the flucloxacillin and gentamicin group [7.79 (95% confidence interval 3.54–17.14), P Conclusions Our findings suggest that the use of prophylactic high-dose flucloxacillin and gentamicin should be used with caution in patients undergoing primary hip or knee arthroplasty without a clear advantage in reducing surgical site infections given the association with increased rates of AKI.

Background: The objective of this study was to determine the prevalence of radiolucent lines (RLLs) around the femoral component in a cohort of patients who underwent well-functioning cementless total hip arthroplasty (THA). Methods: A cohort of unrevised Corail (DePuy Synthes, Raynham, MA) femoral components (n = 636) were analyzed at a median follow-up of 6.0 years (interquartile range: 5.2-6.8) with the Oxford Hip Score (OHS) and radiographs. Two independent observers assessed the radiographs for the presence of RLLs. Results: The overall prevalence of RLLs in zone 7 was 13% (83/636). Patients with RLLs in zone 7 had an average OHS of 40.3 (15-48), and those who did not have RLLs in zone 7 had an average OHS of 38 (6-48), P = .07. Both groups had an average pain score of 1.6 out of 5, P = .5. The prevalence of RLLs in zone 7 was much less in the collared femoral components (2.6% prevalence) than in the collarless components (23.6% prevalence), but there was heterogeneity between these 2 groups preventing comparison. Logistic regression analysis of only the collarless components identified undersizing as the only predictive (odds ratio = 2.6) factor for RLL development in zone 7. Conclusions: Undersizing the Corail stem is strongly predictive of developing RLLs in zone 7. Preoperative templating for the appropriate size is critical. We observed more RLLs in zone 7 with the collarless design Corail, but a comparison study with the same bearing couple is needed to investigate this further. Keywords: Hip, Uncemented, Cementless, Templating, Collar, Corail

Background With the demand for arthroplasty increasing worldwide year on year, there is a drive to improve prosthesis longevity. Biological fixation from cementless implants has been one method of trying to achieve this. We hypothesized that the addition of a hydroxyapatite (HA) coating and 4 pegs to a porous-coated tibial tray would provide a reduction in time to implant osseointegration, allowing for normal physiological stress transfer, thus improving early postoperative pain and rehabilitation as well as the elimination of radiolucent lines (RLLs). Methods A prospective, randomized controlled single-blinded study was undertaken, comparing postoperative pain, radiographic evidence of biological fixation, and clinical outcomes between patients undergoing primary total knee arthroplasty with either LCS Complete POROCOAT (porous coating only) or LCS Complete DUOFIX (porous coating plus HA and pegs) knee systems (DePuy Synthes, Warsaw, IN). In total, 197 patients (205 knees) were recruited into the study between November 2006 and November 2008 and have been followed for up to 10 years. Results There were no clinically significant differences in pain or patient-reported outcome measures when comparing the 2 designs but the tibial tray with pegs and HA showed fewer RLLs at all time points. There was no correlation between RLLs and pain and no instances of loosening or osteolysis in either group. There was 1 revision for infection in the porous coating only group. Conclusion The tray design with HA and additional fixation pegs did not confer any benefit in terms of reduced early postoperative pain or improved patient-reported outcomes, although it did result in significantly fewer RLLs. Both implants demonstrated excellent survivorship. With a cementless porous-coated tibial component, nonprogressive RLLs should be considered normal.

Smjernice za prevenciju tromboembolijskih incidenata prilikom ortopedskih zahvata na kuku i koljenu.

Aims In total knee arthroplasty (TKA), blood loss continues internally after surgery is complete. Typically, the total loss over 48 postoperative hours can be around 1,300 ml, with most occurring within the first 24 hours. We hypothesize that the full potential of tranexamic acid (TXA) to decrease TKA blood loss has not yet been harnessed because it is rarely used beyond the intraoperative period, and is usually withheld from ‘high-risk’ patients with a history of thromboembolic, cardiovascular, or cerebrovascular disease, a patient group who would benefit greatly from a reduced blood loss. Methods TRAC-24 was a prospective, phase IV, single-centre, open label, parallel group, randomized controlled trial on patients undergoing TKA, including those labelled as high-risk. The primary outcome was indirect calculated blood loss (IBL) at 48 hours. Group 1 received 1 g intravenous (IV) TXA at the time of surgery and an additional 24-hour postoperative oral regime of four 1 g doses, while Group 2 only received the intraoperative dose and Group 3 did not receive any TXA. Results Between July 2016 and July 2018, 552 patients were randomized to either Group 1 (n = 241), Group 2 (n = 243), or Group 3 (n = 68), and 551 were included in the final analysis. The blood loss did differ significantly between the two intervention groups (733.5 ml (SD 384.0) for Group 1 and 859.2 ml (SD 363.6 ml) for Group 2; mean difference -125.8 ml (95% confidence interval -194.0 to -57.5; p < 0.001). No differences in mortality or thromboembolic events were observed in any group. Conclusion These data support the hypothesis that in TKA, a TXA regime consisting of IV 1 g perioperatively and four oral 1 g doses over 24 hours postoperatively significantly reduces blood loss beyond that achieved with a single IV 1 g perioperative dose alone. TXA appears safe in patients with history of thromboembolic, cardiovascular, and cerebrovascular disease. Cite this article: Bone Joint J 2021;103-B(10):1595–1603.

Virtual patient assessment will inevitably require smartphone technology to remotely measure knee range of motion. We conducted an experiment to analyze the impact of observer position relative to the flexed knee on the perceived angle measured using an electronic application (Dr. Goniometer) for iPhone. Two observers measured the apparent knee flexion angle from 7 different positions at 3 different heights relative to the center of the knee joint. Intraclass correlations were calculated to evaluate the intraobserver and interobserver variability using two-way mixed-effects models. The intraclass correlation for interobserver variability was excellent at 0.804 (95% confidence interval 0.663-0.889). When the observer was greater than 15° from the knee perpendicular, the true angle of knee flexion (90°) was not observed in any of the measurements. This was the case when observed from both proximal (range 95°-121°) and distal (range 92°-108°) directions. Ideally the camera lens should be perpendicular to the long axis of the lower limb in the proximal-distal direction and at the same height. However, if the camera lens is within 15° of the perpendicular, then at 90° of true flexion, the perceived angle will not be greater than 95° in 94% of cases.

Background Increasing numbers of Total Knee Arthroplasty (TKA) operations are carried out worldwide each year. This brings with it an ever-increasing revision burden and it is therefore important to appreciate both the functional outcome and survivorship of established arthroplasties when considering new designs. We aim to evaluate the long-term survivorship of a fully cemented mobile bearing Total Knee Arthroplasty. Methods This study prospectively analyses the 20-year survivorship of a cohort of 487 consecutive patients who underwent cemented TKA under the care of a single surgeon using the Low Contact Stress (LCS) rotating platform (RP) implant. These patients were followed up prospectively with patient reported and functional outcomes recorded at regular intervals postoperatively. Results Five hundred and forty-two consecutive primary TKAs were carried out in 487 patients. A total of 139 knees (25.6%) were reviewed at 20 years post-operation. Overall cumulative survivorship, using revision for any reason as primary endpoint, was 98.0%. Mean Knee Society Scores for the patient cohort were 87.3 (Clinical score) and 52.5 (Functional score). Eleven (2.0%) were revised within 20 years — two for aseptic loosening, two for unexplained pain, five secondary patellar resurfacings for anterior knee pain, one for late infection and one liner exchange following spin-out. Conclusion This series demonstrates excellent survivorship and satisfactory outcome of a cemented mobile bearing TKA at 20 years.

Background Previous studies report that gait parameters of patients following total hip replacement improve from pre-operative levels, although in most cases do not reach those of normal subjects. However, studies are generally of unilateral total hip replacement patients at short-term follow-up. There have been no reports of 3D gait kinematics and kinetics in patients with bilateral total hip replacements at long-term follow-up. The aim of this study was to compare temporospatial parameters and 3D lower limb gait kinematics and kinetics at long-term follow-up between limbs and against controls for patients who have undergone staged bilateral total hip replacement. Methods 3D gait analysis was performed on 13 patients who had undergone bilateral total hip replacement, at an average follow-up of 10.1 (first hip) and 9.3 years (second hip), and a normal elderly control group comprising 10 subjects. Findings Knee flexion/extension range of motion was marginally greater in Hip 2 (p = 0.049) compared to Hip 1 by 3.2°. There were no other significant differences in temporospatial parameters or a range of lower limb kinematics or kinetics between the first and second operated hip. Multiple gait parameters were significantly worse for both hips compared to age-matched normal individuals. Interpretation Although symmetrical biomechanical recovery was achieved, significant gait deficiencies remain in both hips compared to normal controls. These deficits may provide targets for enhanced rehabilitation programs.

Background Particularly in broach-only uncemented total hip arthroplasty, a narrow femoral canal presents a technical challenge. Traditionally such femurs have been considered to be Dorr A. To our knowledge, however, no study has reported on the relationship between isthmus width and the Dorr classification. Method We reviewed 500 high-quality, hard copy radiographs. Dorr classification and isthmus canal width were measured using an electronic caliper by 5 independent observers with intraobserver and interobserver error calculated. For this study, we defined a narrow canal as being 10 mm at its narrowest point (isthmus). Results Eight percent (40) were Dorr A, 85% (424) Dorr B, and 7% (36) Dorr C. With respect to isthmus width for Dorr A, 63% (25) were 10 mm compared to just 13% (55) of Dorr B. However, overall because there were more Dorr B femurs, 69% of those with an isthmus of 10 mm were Dorr B. Conclusions In this population, almost 70% of patients with an isthmus 10 mm were Dorr B, with only 30% being Dorr A. When using a broach-only technique, isthmus width should be routinely measured on the preoperative anteroposterior radiographs so as to alert the surgeon to potential problems.

AimsUp to one in five patients undergoing primary total hip (THA) and knee arthroplasty (TKA) require contralateral surgery. This is frequently performed as a staged procedure. This study aimed to determine if outcomes, as determined by the Oxford Hip Score (OHS) and Knee Score (OKS) differed following second-side surgery.MethodsOver a five-year period all patients who underwent staged bilateral primary THA or TKA utilizing the same type of implants were studied. Eligible patients had both preoperative and one year Oxford scores and had their second procedure completed within a mean (2 SDs) of the primary surgery. Patient demographics, radiographs, and OHS and OKS were analyzed.ResultsA total of 236 patients met the inclusion criteria, of which 122 were THAs and 114 TKAs. The mean age was 66.5 years (SD 9.4), with a 2:1 female:male ratio. THAs showed similar significant improvements in outcomes following first- and second-side surgery, regardless of sex. In contrast for TKAs, although male patients demonstrated the same pattern as the THAs, female TKAs displayed significantly less improvement in both OKS and its pain component following second-side surgery.ConclusionFemale patients undergoing second-side TKA showed less improvement in Oxford and pain scores compared to the first-side. This difference in outcome following second-side surgery did not apply to male patients undergoing TKA, or to either sex undergoing THA. Cite this article: Bone Jt Open 2021;2(4):243–254.

Background Decision regret (DR) is a recognised patient centered outcome measure following a therapeutic intervention. This study aimed to measure DR following primary total hip and knee arthroplasty (THA/TKA), to assess for differences between these patients and explore possible contributory factors. Method DR was measured using the DR scale in a group of THA and TKA patients, between February 2017 and December 2018, who had made a decision to have joint replacement surgery within the previous year and were able to reflect on their outcomes. Results On analysis a significantly greater proportion of TKA patients reported moderate or severe (Mod/Sev) DR [17.1% (56/328)] compared to THA patients [4.8% (18/376)]. Conversely, a significantly reduced proportion of TKA patients reported having No DR [42.1% (138/328)] compared to THA patients [66.7% (251/376)]. On multivariate logistic regression analysis joint replacement type (TKA/THA) and change in Oxford score were significant predictors of DR with gender, age, BMI and ASA grade not significantly associated. TKA patients were more than twice as likely to have Mod/Sev DR compared THA patients (Odds Ratio = 2.33 (95% CI 1.24–4.39)). Patients with poorer improvements in pain and function 1-year post-operatively (measured by Oxford scores) reported greater levels of DR. Conclusion TKA patients were significantly more likely to report greater levels of DR 1-year following surgery compared to THA patients. For both TKA and THA patients, greater levels of DR were associated with poorer Oxford scores. The use of decision aids to reduce post-operative DR in joint replacement patients should be examined especially for knee replacement patients.

Aims Previous research has demonstrated increased early complication rates following total hip arthroplasty (THA) in obese patients, as defined by body mass index (BMI). Subcutaneous fat depth (FD) has been shown to be an independent risk factor for wound infection in cervical and lumbar spine surgery, as well as after abdominal laparotomy. The aim of this study was to investigate whether increased peritrochanteric FD was associated with an increased risk of complications in the first year following THA. Methods We analyzed prospectively collected data on a consecutive series of 1,220 primary THAs from June 2013 until May 2018. The vertical soft tissue depth from the most prominent part of the greater trochanter to the skin was measured intraoperatively using a sterile ruler and recorded to the nearest millimetre. BMI was calculated at the patient’s preoperative assessment. All surgical complications occuring within the initial 12 months of follow-up were identified. Results Females had a significantly greater FD at the greater trochanter in comparison to males (median 3.0 cm (interquartile range (IQR) 2.3 to 4.0) vs 2.0 cm (IQR 1.7 to 3.0); p < 0.001) despite equivalent BMI between sexes (male median BMI 30.0 kg/m2 (IQR 27.0 to 33.0); female median 29.0 kg/m2 (IQR 25.0 to 33.0)). FD showed a weak correlation with BMI (R² 0.41 males and R² 0.43 females). Patients with the greatest FD (upper quartile) were at no greater risk of complications compared with patients with the lowest FD (lower quartile); 7/311 (2.3%) vs 9/439 (2.1%); p = 0.820 . Conversely, patients with the highest BMI (≥ 40 kg/m2) had a significantly increased risk of complications compared with patients with lower BMI (< 40 kg/m2); 5/60 (8.3% vs 18/1,160 (1.6%), odds ratio (OR) 5.77 (95% confidence interval (CI) 2.1 to 16.1; p = 0.001)). Conclusion We found no relationship between peritrochanteric FD and the risk of surgical complications following primary THA. Cite this article: Bone Joint J 2020;102-B(9):1146–1150.

Introduction Polyethylene (PE) spinout is a known but uncommon complication when using a mobile-bearing (MB) total knee arthroplasty (TKA) design. Sacrificing the posterior cruciate ligament (PCL) is within the manufacturer’s recommendations for the Attune® Cruciate-Retaining Rotating-Platform (CR RP) knee design. Aim To discuss the potential aetiology and prevention of spinout in the Attune® CR RP knee. Methods We used a retrospective radiological review from two centres reporting a higher rate of spinout in the Attune® CR RP knee using a cruciate-sacrificing and measured-resection technique when compared to a gap-balancing technique. Three hundred and thirty-two patients were evaluated over a 3-year period. Results There were 8 out of 279 (2.86%) cases of spinout in our first cohort of patients using a measured-resection technique. There were 0 out of 53 cases of spinout in our second cohort of patients where a gap-balancing technique was used. One spinout was reduced closed, the other seven were initially revised to a thicker RP insert of the same design. Of these seven, three underwent a further revision TKA and one patient required a knee fusion/arthrodesis. Conclusions This study reports a higher incidence of PE spinout in the Attune® CR RP TKA when a measured-resection technique in combination with PCL resection is performed. We recommend a gap-balancing technique with conservative soft-tissue release if the surgeon is planning to sacrifice the PCL in the Attune® CR RP.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes a range of extra-respiratory signs and symptoms. One such manifestation is delirium, an acute confusional state occurring in 60-70% of severe SARS-CoV-2 cases. Delirium is also a common clinical syndrome following planned orthopedic surgery. This investigation initially explored the underlying role of metabolism in delirium-susceptibility in this setting. Metabolomics profiles of cerebrospinal fluid (CSF) and blood taken prior to surgery found significant concentration differences of several amino acids, acylcarnitines and polyamines were observed in delirium-prone patients. Phenethylamine (PEA) concentrations in delirium-prone patients was significantly lower in CSF than in blood, whilst in age- and gender-matched controls the opposite was observed (adjusted p values: 1.8x10-6 (control) and 1.788x10-10 (delirium)). PEA is metabolised by monoamine oxidase B (MAOB), a putative enzyme target for the treatment of Alzheimers disease, Parkinsons disease and depression. Our computational structural comparisons of MAOB and angiotensin converting enzyme (ACE) 2 found high similarity, specifically within the SARS-CoV-2 spike protein. MAOB structural alignment to ACE2 was 51% overall, but this was over 95% in the ACE2-spike protein binding region. Thus, it is possible that the spike protein interacts with MAOB on a molecular level. A previously published metabolomic dataset of control subjects and patients with either mild or severe COVID-19 was then analysed. Major concentration differences in some metabolites attributed to altered MAO activity were detected. Therefore, our hypothesis is that the SARS-CoV-2 influences MAOB activity, which is one potential cause for the many observed neurological and platelet based complications of SARS-CoV-2 infection.

Aims: To determine the outcome at 10 years of a cohort of ASR XL total hip arthroplasties (THAs) and reasons for revision. Methods: Between November 2005 and May 2007, 122 ASR XL THAs were implanted. All patients had a routine review at 6 weeks and 1 year, followed by a review in 2009 because of clinical concern and thereafter annual review up to 10 years with MRI. Review also included functional scores, radiographs, pain scores and blood metal ions. Results: 67 (54.9%) ASR XLs had been revised by 11.1 years. Reasons for revision included pain (89.6%), high levels of cobalt and chromium ions (50.7%) and radiographic or MRI changes (80.6%). All 3 factors were present in 23 (34.3%). Pain at 1 year did not predict revision, but pain at the 2009 review did. At 10 years the revised patients had an average Oxford Hip Score (OHS) of 25.38 (12–42) and the non-revised 23.61 (2–21), the difference was not significant ( p = 0.48). 3 patients (4.5%) have had a further revision; 2 for a previously unrevised stem and the other for instability. Conclusions: Our arthroplasty care practitioner service allowed us to identify increased pain and stop using the ASR XL over 3 years before the implant was recalled. The revised patients had similar functional outcome to those unrevised. Poorly performing implants need to be identified earlier.

Rapidly progressive osteoarthritis (RPO) is a rare condition which is poorly understood. Limited published literature is available. Reported here is a cohort of patients with RPO and acetabular bone loss who underwent primary THA. Risk factors, degree of acetabular bone loss and outcomes are presented. A typical case of RPO is described and investigations discussed. A retrospective audit was undertaken. 49 patients over an 18-year period were included. RPO patients were significantly older (P < 0.01) and had a lower BMI (P = 0.03). The mean acetabular bone loss in this cohort was 10.0 mm. Pathogenesis and risk factors for developing RPO remain unclear and future research is necessary. Repeat imaging in patients with deteriorating symptoms is important and urgent surgery is required maintain bone stock.

BACKGROUND: Reduced flexion following knee arthroplasty (TKA) may compromise patient’s function and outcome. The timing of manipulation under anaesthesia (MUA) has been controversial. We present our experience in a high volume practice and analyse the impact of timing. METHODS: All TKA patients requiring MUA from February 1996 to June 2015 under the care of a single surgeon were analysed. MUA was offered to patients who had ≤ 75° of flexion post-op, providing that they had 30° more flexion preoperatively. To address the impact of timing from primary surgery to MUA on flexion gain we looked at 3 groups: Group I ≤ 90 days, Group II 91-180 days and Group III > 180 days. RESULTS: Sixty two out of 7,423 (0.84%) underwent MUA. The MUA patients were significantly younger than the overall TKA cohort 61.2 vs 70.5 years (p = 180 days) both at 6 weeks and 1 year following MUA but not better than group II (90-180 days). CONCLUSIONS: MUA is an effective treatment for reduced flexion following TKA and should be the first line of management after failed physiotherapy. It can still have benefit beyond 6 months but the gains become less effective with time.

Background: The use of tranexamic acid (TXA) in total hip replacement (THR) typically reduces blood loss by approximately 400 mL, and typical total blood loss is still approximately 1 L. A barrier to harnessing the full potential of TXA is disagreement on the optimum timing of administration. To address this, we aimed to identify the period of greatest blood loss. Methods: We analyzed the perioperative data of 870 patients who had undergone THR, total knee replacement, or unicompartmental knee replacement just before the introduction of TXA to our unit. Total blood loss was calculated on postoperative day (POD) 1 and POD2 using an equation based on change in hematocrit. Results: Average total blood loss at POD2 was 1505, 1322, and 611 mL for THR, total knee replacement, and unicompartmental knee replacement, respectively. Between 86% and 96% of this blood loss occurred in the period between skin closure and POD1. Intraoperative loss did not correlate with total loss at POD2. Blood transfusion was more likely if the patient was female (odds ratio [OR], 6.8) or if they had preoperative anemia (OR, 8.3) than if there was a high-volume blood loss (OR, 1.6). Conclusions: Approximately 90% of blood loss occurs between skin closure and the first postoperative 24 hours. “Intraoperative blood loss” and “transfusion rate” are not reliable markers of total blood loss. The full potential of TXA could be harnessed by using it during the period of greatest blood loss, that is, during the first postoperative 24 hours. Keywords: Arthroplasty, Hip, Knee, Blood loss, Tranexamic acid

Variation in hip joint contact forces directly influences the performance of total hip replacements (THRs). Measurement and calculation of contact forces in THR patients has been limited by small sample sizes, wide variation in patient and surgical factors, and short-term follow-up. This study hypothesised that, at long-term follow-up, unilateral THR patients have similar calculated hip contact forces compared to controls walking at similar (self-selected) speeds and, in contrast, THR patients walking at slower (self-selected) speeds have reduced hip contact forces. It was further hypothesised that there is no difference in calculated hip contact forces between operated and non-operated limbs at long-term follow-up for both faster and slower patients. Gait analysis data for THR patients walking at faster (walking speed: 1.29 ± 0.12 m/s; n = 11) and slower (walking speed: 0.72 ± 0.09 m/s; n = 11) speeds were used. Healthy subjects constituted the control group (walking speed: 1.36 ± 0.12 m/s; n = 10). Hip contact forces were calculated using static optimisation. There was no significant difference (p > 0.31) in hip contact forces between faster and control groups. Conversely, force was reduced at heel strike by 19% (p = 0.002), toe-off by 31% (p < 0.001) and increased at mid-stance by 15% (p = 0.02) for the slower group compared to controls. There were no differences between operated and non-operated limbs for the slower group or the faster group, suggesting good biomechanical recovery at long-term follow-up. Loading, at different walking speeds, presented here can improve the relevance of preclinical testing methods.

Background The theoretical benefits of a mobile bearing design in Total Knee Arthroplasty (TKA) include increased articular surface conformity with a reduction in both polyethylene wear and implant interface shear. However, to date these theoretical advantages have not been translated into published evidence of superior survivorship. This paper presents the results of a prospective, non-comparative study evaluating the performance of the mobile bearing Low Contact Stress LCS Complete Rotating Platform TKA in a largely cementless cohort without patellar resurfacing. Methods 237 consecutive patients (240 knees) undergoing primary TKA were prospectively recruited. All received the LCS Complete Rotating Platform TKA (DePuy International, Leeds, UK). Clinical and radiographic assessments were performed at 3, 12, 60 and 120 months post-operatively. Radiographic evaluation was performed by an independent external surgeon. Results The mean age was 70.3 years. 77.5% of cases were cementless. Radiographic assessment suggested excellent femoral component fixation. 22 tibial radiolucent lines (RLLs) > 1 mm were observed in 12 knees. No RLLs were progressive. There have been two revisions; one for late infection and one for aseptic loosening. No patients underwent secondary patellar resurfacing. The cumulative implant survivorship, using component revision for any reason as the endpoint, was 98.9% (95% CI, 95.6 to 99.7%) at 10 years. Conclusions The excellent survivorship at a minimum 10-year follow-up supports the use of uncemented porous coated fixation without patellar resurfacing with the non-posterior stabilized LCS Complete Rotating Platform TKA.

Excellent medium-term to long-term results for function and survivorship have been shown with mobile-bearing (MB) total knee arthroplasty (TKA). One of the key arguments against its use is the risk of "spinout" or dislocation of the MB. The aim of this study is to discuss the etiology, prevention, incidence, management, and outcome of spinout.Between October 1993 and February 2016, 8373 consecutive primary MB TKAs were performed irrespective of preoperative deformity. Before 2001, soft-tissue knee balancing was achieved by release of collateral ligaments and all spinouts were treated by open reduction. Thereafter, soft-tissue balancing was achieved without ligament release and with the use of a higher conformity MB and all spinouts were reduced closed, giving 2 comparative cohorts.Twenty-six spinouts occurred in 8373 (0.31%) patients. In the first cohort up until May 2001, there were 14 spinouts of 2379 (0.58%) cases. There were 12 in cohort 2, in those patients having surgery after May 2001, thus giving an incidence of 12 of 5994 (0.2%), which was significantly lower than in cohort 1 (P.01). Spinout was associated with the valgus knee (P.01) and most (73%) occurred within the first 6 months. There was 1 arthrodesis in cohort 1 and 1 both-component revision in cohort 2.The etiology of spinout is flexion gap instability. It can normally be reduced closed with recurrence being uncommon. Focus on soft-tissue balance necessary with an MB TKA can reduce the incidence of revision for instability as compared to a fixed-bearing TKA. Therefore, the risk of spinout should not be used as an argument against the MB TKA.

Background It is not known if lower limb gait kinetics of total hip replacement (THR) patients reach normal levels at long term follow-up post-operatively. Methods Three-dimensional gait analysis was performed on 134 THR patients with identical implants 10-years post-operatively. Lower limb moments and powers were compared between different age strata (54–64 years, 65–69 years, 70–74 years, 75–79 years and over 80 years) and a normal elderly control group. Results Hip extensor moment and hip power generation were significantly reduced in all age groups compared to normal. External hip rotation moment was significantly reduced in all age groups, apart from the youngest group, compared to normal. However, in contrast to previous short term follow-up studies there was no significant difference in hip abduction moment between any of the age groups and the normal group. Conclusion This large cohort study shows that, at long term follow-up following THR, some hip joint kinetics (hip extensor and external rotation moments and hip power generation) do not reach normal levels, but that peak abduction moment is preserved. THR patients recovery could potentially benefit from intensive rehabilitation focusing on hip extension and external rotation in the post-operative, and perhaps preoperative, period.

Background The use of a cemented cup together with an uncemented stem in total hip arthroplasty (THA) has become popular in Norway and Sweden during the last decade. The results of this prosthetic concept, reverse hybrid THA have been sparsely described. We report our experience of reverse hybrid THA, using the Elite plus polyethylene cemented cup together with the Corail fully hydroxyapatite-coated uncemented stem and a 28-mm alumina ceramic head. Patients and methods 132 consecutive reverse hybrid hip arthroplasties were performed from January 2000 to December 2003 in 126 patients with a mean age of 54.3 years (28-65). All patients were routinely reviewed at 3 months, 1, 5, 7 and 10 years postoperatively. At each follow-up patients were seen either by a consultant orthopaedic surgeon or a senior trainee. Anteroposterior pelvic and lateral x-rays of the hip were taken at each visit. To estimate the survival of the THAs we used the Kaplan-Meier method with 95% confidence interval (CI). Logistic regression analysis was performed to determine which factors affected the presence of radiolucency around the femoral stem. Results The mean follow-up was 11.1 years (9.0-14.2). 1 patient was lost to follow-up, and 7 patients were deceased at the time of 10-year follow up. At 10 years 7 patients have had further surgery. 5 for infection, 1 periprosthetic femoral fracture and 1 heterotopic bone formation. All stems were classified as well fixed. 2 cups were defined as loose at 10 years. 1 patient is scheduled for revision the other refused revision. The clinical outcome and radiological findings were assessed in 123 hips. The mean Harris Hip Score was 94 (35-100) at 10 years and the mean WOMAC score was 89 (30.2-100). Conclusions We report good results with respect to clinical outcome and survival of the reverse hybrid concept in patients younger than 65. A successful outcome depends on meticulous preoperative planning, use of modern cementing techniques in the acetabulum and experience in implanting an uncemented stem.

Ceramic earrings have an established and successful history in total hip replacement. Occasionally, these articulations have problems, which include squeaking and implant fracture.

Background There are morphologic differences between males and females, which are currently underappreciated during total hip arthroplasty. We sought to assess whether these differences affected surgical process and subsequent outcome. Methods A total of 123 patients (75 females, 48 males) had preoperative and 1-year Oxford Hip Score (OHS) and pain scores recorded. Acetabular height and offset, femoral height and offset, and acetabular floor depth were measured on preoperative and postoperative X-rays and then compared to their normal opposite hip. Discrepancies between the replaced and normal hip X-ray measurements were then correlated with changes (the delta gain) in preoperative and 1-year postoperative OHS and pain scores. Results Postoperatively, females had significantly greater femoral height discrepancy (P = .023) which meant they were lengthened. This led to a reduced delta gain in OHS and pain score at 1 year. Males lost more acetabular offset than females (P = .002), leading to a medialized acetabular center and subsequently reduced delta gain in pain score at 1 year (P = .017). Conclusion Females have a smaller femur leading to a bias toward a conservative (higher) neck cut compared with males and potential for femoral lengthening. Males have a greater acetabular floor depth compared with females and thus reaming to the true floor results in greater loss of acetabular offset. In this series, both scenarios led to reduced improvement in OHS and/or pain scores at 1 year.

OBJECTIVE: To test the hypothesis that APOE ε4 status and cerebrospinal fluid (CSF) Aβ42, T-tau and P-tau would independently predict the risk of postoperative delirium.BACKGROUND: Delirium following surgery is common and associated with adverse outcomes. Age and cognitive impairment are consistent risk factors for postoperative delirium.METHODS: This observational cohort study recruited 282 participants aged 65 years or older, without a diagnosis of dementia, admitted for primary elective hip or knee arthroplasty. Cognitive tests were undertaken preoperatively, blood and CSF were sampled at the time of spinal anesthesia, and participants were assessed daily postoperatively for delirium.RESULTS: Increasing age (P = 0.04), preoperative comorbidity (P = 0.03), type of surgery (P = 0.05), intravenous opioid usage (P = 0.04), and low CSF Aβ42 (P < 0.01) were independent predictors of postoperative delirium.CONCLUSIONS: This study is the first to show an independent association between CSF Aβ42 and delirium incidence in an elective surgical population, suggesting that postoperative delirium may indicate incipient Alzheimer disease.

Delirium is a marker of brain vulnerability, associated with increasing age, pre-existing cognitive impairment and, recently, cerebrospinal fluid (CSF) biomarkers of Alzheimer’s disease. This nested case-control study used a targeted quantitative metabolomic methodology to profile the preoperative CSF of patients (n = 54) who developed delirium following arthroplasty (n = 28) and those who did not (n = 26). The aim was to identify novel preoperative markers of delirium, and to assess potential correlations with clinical data. Participants without a diagnosis of dementia (≥65 years) undergoing elective primary hip or knee arthroplasty were postoperatively assessed for delirium once-daily for three days. Groups were compared using multivariate, univariate and receiving operator characteristic (ROC) methods. Multivariate modelling using Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA) of metabolomic data readily distinguished between delirium and control groups (R2 ≤ 0.56; Q2 ≤ 0.10). Three metabolites (spermidine, putrescine and glutamine) significantly differed between groups (P 0.75). The biomarker performance of the two polyamines (spermidine/putrescine) was enhanced by ratio with CSF Aβ42 (ROC > 0.8), and spermidine significantly correlated with Aβ42 (pearson r = −0.32; P = 0.018). These findings suggest that spermidine and putrescine levels could be useful markers of postoperative delirium risk, particularly when combined with Aβ42, and this requires further investigation.

Background Restoration of native hip biomechanics is viewed as a key intra-operative goal in total hip arthroplasty (THA). The transverse acetabular ligament (TAL) can aid in the restoration of acetabular height and offset, and a calliper can be utilised to restore femoral height and offset. This study aimed to determine how these techniques affected the incidence of patient perception of limb length discrepancy (LLD), and if restoration of native biomechanics correlated with improved patient outcomes. Methods 123 patients were questioned regarding perception of LLD at 6 weeks and 1 year following THA. Oxford hip score (OHS) and pain scores were recorded. Radiographs were analysed by a blinded clinician who measured three variables; Global hip height (surrogate for limb length), global offset and the combination of both. These measurements were then compared to the unaffected contralateral hip. Data were analysed based on hips that were restored to within ≤±10 mm of native values, and those >±10 mm. Spearman's rank test was used to assess correlation with outcome. Results 8 (6.5%) patients perceived a LLD at 6 weeks, reducing to 3 (2.4%) at 1 year-lower than generally reported. Those patients not restored within ±10 mm of native global height had increased pain at 1 year (r = 0.558, p = 0.047). Those not restored within ±10 mm native global offset had a poorer OHS at 1 year (r = −0.586, p = 0.035) and those patients with combined height and offset discrepancy >±10 mm had both a worse OHS (r = −0.581, p = 0.037) and increased pain (r = 0.783, p = 0.002). Conclusion Patient perception of LLD is complex and relates poorly to radiographic measurement, however, patients not restored to within 10 mm of native hip height and offset have demonstrated poorer outcomes.

Orthopaedic surgeons often experience a mismatch between perceived intra-operative and radiographic acetabular cup orientation. This research aimed to assess the impact of pelvic orientation and surgical positioning technique on operative and radiographic cup orientation. Radiographic orientations for two surgical approaches were computationally simulated: a mechanical alignment guide and a transverse acetabular ligament approach, both in combination with different pelvic orientations. Positional errors were defined as the difference between the target radiographic orientation and that achieved. The transverse acetabular ligament method demonstrated smaller positional errors for radiographic version; 4.0° ± 2.9° as compared to 9.4° ± 7.3° for the mechanical alignment guide method. However, both methods resulted in similar errors in radiographic inclination. Multiple regression analysis showed that intraoperative pelvic rotation about the anterior-posterior axis was a strong predictor for these errors (B TAL = −0.893, B MAG = −0.951, p < 0.01). Application of the transverse acetabular ligament method can reduce errors in radiographic version. However, if the orthopaedic surgeon is referencing off the theatre floor to control inclination when operating in lateral decubitus, this is only reliable if the pelvic sagittal plane is horizontal. There is currently no readily available method for ensuring that this is the case during total hip replacement surgery.

Background In total hip arthroplasty the surgeon aims to restore the biomechanics of the joint. Femoral height has the greatest influence on restoring limb length and contributes equally to the restoration of femoral head centre. On X-ray, the level of femoral neck resection is most often referenced off the upper border of lesser trochanter. Less frequently, femoral head centre is referenced from the tip of the greater trochanter. The error in measurement of femoral height resulting from unknown femoral rotation is crucially important and can result in inappropriate surgical planning for implant selection and placement. It is unknown which reference produces lower error. Methods A sample of femoral shapes was generated using a femoral statistical shape model. These were placed in a range of orientations in terms of external rotation and flexion, at intervals of 10°. Simulated X-rays were then produced and the distances from the tip of either greater or lesser trochanter to femoral head centre were measured. Findings Although using greater trochanter as a reference demonstrated greater errors at the extremes, both techniques resulted in errors of 7–8 mm with 20° of both femoral external rotation and flexion. Interpretation Moderate degrees of femoral external rotation combined with flexion can result in unsatisfactory errors when templating limb length. There should be greater focus and an agreed definition for femoral height. There is a clinical need for a method with a lower error in determining true femoral height and the level of neck resection.

Peripheral neuropathy is a rare but important complication of total hip arthroplasty (THA) and has previously been reported in the ipsilateral arm and associated with inflammatory arthritis. The results of 7004 primary hip arthroplasties performed between January 1993 and February 2009 were retrospectively reviewed to identify patients who reported ulnar neuropathy symptoms, with ten patients identified at mean follow-up of 57 months (range = 3-195 months). Eight patients experienced unilateral ulnar nerve symptoms in the contralateral upper limb post-surgery, one patient experienced symptoms in the ipsilateral upper limb and one patient experienced symptoms in both upper limbs. The incidence of post-THA ulnar neuropathy was 0.14%. All patients had a pre-operative diagnosis of osteoarthritis and none had diabetes, a previous history of neuropathy or inflammatory arthritis. All operations were primary arthroplasties and were performed under the care of a single surgeon in a single centre. Two of the ten patients (20%) had a general anaesthetic. The pattern of symptoms reported, i.e. mainly unilateral affecting the contralateral side with variable resolution, contrasts with previous studies and suggests that intraoperative patient positioning may be an important factor influencing ulnar neuropathy following THA. Attention to support and positioning of the contralateral arm may help reduce the incidence of this complication.

Aims The aim of this study was to present data on 11 459 patients who underwent total hip (THA), total knee (TKA) or unicompartmental knee arthroplasty (UKA) between November 2002 and April 2014 with aspirin as the primary agent for pharmacological thromboprophylaxis. Patients and Methods We analysed the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) then compared the 90-day all-cause mortality with the corresponding data in the National Joint Registry for England and Wales (NJR). Results The incidence of PE was 0.6% after THA, 1.47% after TKA and 1.2% after UKA. The 90-day mortality was 0.39% after THA and 0.44% after TKA. No deaths occurred after UKA. The main causes of death were ischaemic heart disease and respiratory failure. PE was responsible for only 18% of deaths. There was a decline in 90-day mortality, from 0.64% between 2002 and 2007, to 0.21% between 2008 and 2013 after THA, and from 0.47% to 0.39% after TKA for the corresponding period. The standardised mortality ratio (SMR) declined from 86.5 (confidence interval (CI) 63.0 to 137.7) to 39.7 (CI 31.2 to 54.3) p = 0.024. The incidence of proximal DVT was 0.3%. Take home message: With individualised risk assessment and as part of a multimodal approach, Aspirin is safe to use as the main thromboprophylactic agent in primary arthroplasty. It is not associated with an increased incidence of symptomatic DVT, PE or death. Cite this article: Bone Joint J 2016;98-B:341-8.

Background Total knee arthroplasty designs can be categorized by bearing design and fixation method. The mobile-bearing concept was developed with the aim of increasing longevity and improving function by reduced polyethylene wear and closer replication of physiological knee motion. Cementless fixation has the goal of achieving a long-lasting “biological” fixation between prosthesis and bone. Methods Prospective analysis of the survivorship and patient-reported functional outcomes of a series of 500 low contact stress rotating-platform mobile-bearing total knee arthroplasties with a cementless tibial component with a minimum 17-year follow-up. Results Five hundred primary total knee arthroplasties were conducted in 467 patients. Mean follow-up was 18.1 (17.0-21.8) years and 141 (28.2%) knees were alive and available for review. Using revision for any cause as the end point, cumulative survivorship was 97.4%. Thirteen knees required revision: 3 for deep infection, 3 bearing only revisions for spinout, 3 for tibial tray subsidence, 2 secondary patella resurfacings, 1 aseptic loosening, and 1 for suspected aseptic loosening that was found to be well fixed. Mean American Knee Society Scores were 83 (evaluation) and 48 (function), Mean Oxford Knee Score was 32.1, and the mean Bartlett Patellar Score was 21.6. Conclusion This series demonstrates excellent survivorship and acceptable patient-reported functional outcome scores of a mobile-bearing total knee arthroplasty with a cementless tibial tray at minimum 17-year follow-up.

Introduction: Radiological inclination (RI) is determined in part by operative inclination (OI), which is defined as the angle between the cup axis or handle and the sagittal plane. In lateral decubitus the theatre floor becomes a surrogate for the pelvic sagittal plane. Critically at the time of cup insertion if the pelvic sagittal plane is not parallel to the floor either because the upper hemi pelvis is internally rotated or adducted, RI can be much greater than expected. We have developed a simple Pelvic Orientation Device (POD) to help achieve a horizontal pelvic sagittal plane. Methods: A model representing the posterior aspect of the pelvis was created. This permitted known movement in 2 planes to simulate internal rotation and adduction of the upper hemi pelvis, with 15 known pre-set positions. 20 participants tested the POD in 5 random, blinded position combinations, providing 200 readings. The accuracy was measured by subtracting each reading from the known value. Results: Two statistical outliers were identified and removed from analysis. The mean adduction error was 0.73°. For internal rotation, the mean error was −0.03°. Accuracy within 2.0° was achieved in 176 of 190 (93%) of readings. The maximum error was 3.6° for internal rotation and 3.1° for adduction. Conclusion: In a model pelvis the POD provided an accurate and reproducible method of achieving a horizontal sagittal plane. Applied clinically, this simple tool has the potential to reduce the high values of RI sometimes seen following THA in lateral decubitus.