Abstract. Introduction. Several studies have shown that patients over 65 years have a higher mortality with covid. Combine with inherently increased morbidity and mortality in neck of femur (NoFF) fractures, it is logical to think that this subset would be most at risk. Aims. Investigate whether there is actual increase in direct mortality from Covid infection in NoFF patients, also investigate other contributing factors to mortality with covid positivity and compare the findings with current available literature. Methods. 1-year cross sectional, retrospective study from 1st March 2020 at two DGHs, one in Wales and one in England. Surgically treated NoFF patients with isolated intra/extracapsular fracture included. Mortality analysis done by creating a matched comparison group for each risk factor and combinations known to confer highest mortality. Chi square test for independence used to compare COVID status with 1 year mortality. Results. 610 patients, 62 patients had COVID-19RTPCR+ive test during hospital stay/in the community. 21(34%) deaths in COVID positive and 95 (17.33%) deaths in COVID negative patients. There was no mortality in ASA 1 or 2 patients. Analysis of asa matching with 10-year age ranges from 65years revealed a nearly double mortality rate in covid+ group as opposed to covid negative for both ASA 3 and 4 groups. Parameters such as preinjury mobility, residential status, AMTS score, time to surgery, did not seem to play a significant role in mortality. Conclusion. First of its kind study with a large subset of patients and unique parameters to identify causes leading to mortality in the vulnerable population of NoFF. Higher morality in Covid positive NoFF patients, but increase may not be as significant as identified by most current studies in the literature and still within the confines of NHFD stats(2019). Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Abstract. Introduction. The short and long-term effects of covid infection are still being explored. Following a series of joint infections noted in patients presenting to a tertiary care hospital during the COVID-19 pandemic, we explored if there was any difference in the incidence of these joint infections when compared to pre-COVID era. Aim. The aim of this study was to determine the incidence of native joint infections during COVID and pre-COVID period and compare the two groups for any differences. Methodology. Patients diagnosed with septic arthritis over the 15th months of lockdown were studied and were compared with the same period prior to Covid-19 infection. The patient characteristics, the rate of septic arthritis, the presence of recent Covid-19 infection, delay in diagnosis and the difference in the microbiology between the two groups was studied. Results. There were 36 joint infections during the COVID period in comparison to 46 joint infections during pre-COVID period. Both groups had similar mean age. Knee was the most common joint involved in both groups. About 50% (n = 18) of the joint infections during the COVID period did not grow any micro-organisms even after extended culture, which was higher in comparison to the pre-COVID group (35%, n = 16). Conclusion. The culture negative group have significantly reduced markers of infection. The was no increase in the rate of septic arthritis however there was an increase in culture negative arthritis denoting a possible outbreak of reactive arthritis in the Covid-19 period

In 2020, the COVID-19 pandemic meant that proceeding with elective surgery was restricted to minimise exposure on the wards. In order to maintain throughput of elective cases, our hospital was forced to convert as many cases as possible to same day procedures rather than overnight admission. In this retrospective analysis we review the cases performed as same day arthroplasty surgeries compared to the same period 12 months previous.

We conducted a retrospective analysis of patients undergoing total hip and knee arthroplasties in a three month period between October and December in 2019 and again in 2020, in the middle of the SARS-CoV-2 pandemic. Patient demographics, number of out-patient primary arthroplasty cases, length of stay for admissions, 30-day readmission and complications were collated.

In total, 428 patient charts were reviewed for the months of October-December of 2019 (n=195) and 2020 (n=233). Of those, total hip arthroplasties comprised 60% and 58.8% for 2019 and 2020, respectively. Demographic data was comparable with no statistical difference for age, gender contralateral joint replacement or BMI. ASA grade I was more highly prevalent in the 2020 cohort (5.1x increase, n=13 vs n=1). Degenerative disc disease and fibromyalgia were less significantly prevalent in the 2020 cohort. There was a significant increase in same day discharges for non-DAA THAs (2x increase) and TKA (10x increase), with a reciprocal decrease in next day discharges. There were significantly fewer reported superficial wound infections in 2020 (5.6% vs 1.7%) and no significant differences in readmissions or emergency department visits (3.1% vs 3.0%).

The SARS-CoV-2 pandemic meant that hospitals and patients were hopeful to minimise the exposure to the wards and to not put strain on the already taxed in-patient beds. With few positives during the Coronavirus crisis, the pandemic was the catalyst to speed up the outpatient arthroplasty program that has resulted in our institution being more efficient and with no increase in readmissions or early complications.

Aims

This study aimed to investigate the risk of postoperative complications in COVID-19-positive patients undergoing common orthopaedic procedures.

Aims

This observational study examines the effect of the COVID-19 pandemic upon the paediatric trauma burden of a district general hospital. We aim to compare the nature and volume of the paediatric trauma during the first 2020 UK lockdown period with the same period in 2019.

Aims

To describe the incidence of adverse clinical outcomes related to COVID-19 infection following corticosteroid injections (CSI) during the COVID-19 pandemic. To describe the incidence of positive SARS-CoV-2 reverse transcriptase polymerase chain reaction (RT-PCR) testing, positive SARS-COV2 IgG antibody testing or positive imaging findings following CSI at our institution during the COVID-19 pandemic.

Aims

The UK government declared a national lockdown on 23 March 2020 to reduce transmission of COVID-19. This study aims to identify the effect of lockdown on the rates, types, mechanisms, and mortality of musculoskeletal trauma across Scotland.

Introduction. Neck of femur (NoF) fractures have an inherent 6.5% 30-day mortality as per National hip fracture database(2019). Several studies have demonstrated a higher mortality rate in covid positive NoFs but have been unable to demonstrate whether there are risk factors that contribute to the risk of mortality in this patient group or whether COVID is solely responsible for the higher mortality. Aims. To assess risk factors that are concurrently present in a fracture NoF cohort that may contribute to higher mortality in COVID positive patients. Methods. A cross sectional, retrospective study was performed for a period of 1 year starting from 1st March 2020. All surgically treated neck of femur fracture patients having an isolated intra/extracapsular fracture were included in the study. Data fields recorded- patient demographics, date and time of admission, ward discharge, surgery, mode of surgery (fixation/arthroplasty), prehospital AMTS score, residential status and mobility, ASA grade as per anaesthetist's records, date of death (if deceased), cause of death (as per death certificate/ postmortem / coroner's report). Analysis of mortality was carried out by creating a matched comparison group for each risk factor as well as some combinations. Results. 344 patients were surgically treated for a neck of femur fracture in our DGH during the period of 1st March 2020 to 28th February 2021. 46 patients did not receive a COVID swab (reasons unknown) and were excluded from the study. 35 patients had a COVID-19 RT PCR positive test during their hospital stay and 264 patients remained negative. There were 12 deaths in COVID positive patients (34%) and 53 deaths in COVID negative patients (20%) within the time frame of the study. For each risk factor matched group COVID was seen to confer higher mortality in general. There was no mortality in ASA 1 or 2 patients. Mortality rates in matched groups for age and ASA revealed 23.8% mortality in COVID positive as opposed to 17.3% in COVID negative for ASA 3 and 33.3% mortality in COVID positive vs. 28% in ASA 4. 11 out of the 12 COVID positive patients who died had an AMTS score >6. No correlation was seen between COVID positive deaths and preinjury residential status, type of fracture or surgery offered, or preinjury mobility. The average length of hospital stay was much higher for COVID positive patients (19.5days) as compared to 9.5 days for COVID negative patients. Conclusion. Matched group analysis show that there is a 37.5% increase in COVID positive neck of femur fracture mortality in ASA 3 patients, the same number falls to 17.8% for ASA 4 patients. These figures are much lower compared to other studies in the UK. There is a need to understand the real cause of death in this subset and to improve death certification so that we can differentiate between patients whose mortality is ‘due to’ or ‘With’ COVID

COVID-19 was declared a pandemic by the World Health Organization (WHO) on 11 March 2020. The initial response to the pandemic included the cessation of routine services including elective orthopaedic surgery. There was apprehension among both surgeons and patients about restarting elective surgical services. The high mortality rate in perioperative patients who contract COVID-19 was of particular concern. The aim of this study was to identify the perioperative viral transmission rate in orthopaedic patients at our institution following the restart of elective surgery between August 2020 and November 2020 after the first wave of Covid in the UK. All patients who had their elective Orthopaedic surgeries at our institution from 1st August 2020 to 30th November 2020 were checked whether they were Covid positive or experienced COVID symptoms within 2 weeks after the operation. All patients were advised a 14-day period of comprehensive social distancing, 3 days of self-isolation and had a negative COVID-19 test within 72 hours of surgery and underwent surgery at a COVID free site. The patients were contacted and the hospital database was searched to identify those patients who were Covid positive or had Covid symptoms after the surgery. Baseline patient characteristics were recorded including age, gender, procedure, the subspeciality and admission type. Patients who underwent emergency procedures and trauma operations were excluded. Out of the 499 patients, 315 were contacted over telephone and hospital database was searched for the rest of the patients. We found that none of the patients were positive for COVID or had symptoms of COVID within two weeks of surgery. 5 patients were COVID positive with symptoms few months after the procedure and all of them recovered. There were 144 inpatient admissions and 353 day cases. The development of a COVID-free pathway for elective orthopaedic patients results in very low viral transmission rates. Findings of our study confirms that COVID-free elective pathway is an efficient process, and this could be implemented in future elective Orthopaedic surgeries during COVID times. Elective surgery can be safely resumed using dedicated pathways and procedures -Surgeons, hospital staff and patients should remain vigilant

Abstract. Background. The COVID-19 pandemic has strongly impacted elective orthopaedic surgery. At our trust, a geographically discrete elective site deals with planned orthopaedic surgery. There was a need to define a green pathway to deliver surgical care safely and efficiently, and tackle mounting waiting lists. Methods. Records of patients operated at our elective site, between 1. st. July 2020 and 14. th. January 2021, under a green pathway, including pre-operative self-isolation, COVID screening and segregating perioperative patients, were reviewed, and analysed retrospectively. Patients who did not attend (DNA) their post-operative follow-up appointments were identified. Finally, regional COVID incidence was compared with that in our centre. Results. During this period, 2466 patients were admitted for elective orthopaedic surgery, of which sixteen (0.6%) tested COVID-positive. Among these, two tested positive during asymptomatic in-patient screening, five tested positive within two weeks of discharge, while six tested positive beyond two weeks. One patient tested positive on the day of surgery, which was then postponed. Fourteen (87.5%) patients who tested positive recovered, with two COVID-related mortalities. We identified 34 (1.4%) DNA patients. The COVID incidence in our centre closely paralleled the regional incidence. There were no major COVID outbreaks and no definite evidence of in-hospital transmission. Conclusion. This green pathway has helped streamline patient flow for continuing elective surgery safely through the pandemic, under cautionary monitoring. Modulating elective activity in response to regional COVID rates is vital for addressing waiting lists. Given the encouraging results, this pathway is an effective measure for maintaining elective activity through the pandemic

COVID 19 led to massive disruption of elective services across Scotland. This study was designed to assess the impact on elective service that the COVID-19 pandemic had, to what extent services have been restarted and the associated risks are in doing so. This is a retrospective observational study. The primary outcomes are the number of operations completed, 30-day mortality, 30-day complication rates and nosocomial infection with COVID-19 compared to previous years. Data was collected from 4 regions across Scotland from 27th March 2020 - 26th March 2021. This was compared to the same time period the previous year. 3431 elective operations were completed in the year post-pandemic compared with 12255, demonstrating a reduction of 72%. Both groups had comparable demographics. Major joint arthroplasty saw a 72% reduction, with TKR seeing a reduction of 82%. Each of the 4 health boards were affected in a similar fashion. Nosocomial COVID-19 infection was 0.4% in the post covid group. 30 day mortality was the same at 0.1%. Total complications rose from 5.7% to 10.1% post covid. This study shows that there has been a substantial reduction in elective activity across Scotland that is disproportionate to the level of COVID-19. The risk of developing COVID-19 from elective surgery is low at 0.4%, however all complications saw a significant rise. This is likely multifactorial. This study will inform decision makers in future pandemics, that it is safe to continue elective orthopaedic surgery and of the potential impact of cessation of services

There is a surge of patients on the waiting-list for primary total hip replacement (THR), due to unprecedented reduction of elective activity caused by COVID-19. A higher incidence of femoral head collapse (FC) and acetabular erosion (AE) leading to increase in pain and instability as well as requirement of more complex surgery and potentially higher risk to patients was noted in this period. Rapidly progressive Arthritis (RPA) of the hip is a known entity often described as progression of joint space narrowing greater than 2mm over one year time period. The study aims to identify any potential relationship between waiting time and establishment of femoral head collapse and/ or acetabular erosion. A retrospective review of arthroplasty surgeon's waiting list during COVID. Serial hip radiographs recorded between February 2020 and February 2022 were analysed. FC was quantified as a percentage of the femoral head radius, while AE was assessed by drawing two parallel lines, one through both tear drops and the other through superior most aspect of intact acetabulum, parallel to the inter tear-drop line and expressed as percentage of normal side. Only 105 patients out of 264 patients added to the waiting list had elective arthroplasty for hip/knee. Only 35 patients out of 90 listed for THR, had the surgery. 36 of 90 (40%) were found to have developed FC and fitted the criteria for RPA. Acetabular erosion was seen in 19 (21%). Therefore 53% (19 of 36) of those who developed FC progressed to AE. Incidence of collapse was higher in females (32%), with mean age of 62 (range 51–81), compared to 21% in males with mean age 59 (range 53–87). Mean extent of femoral head collapse was 20% (10 – 44%). A significant proportion of patients added to waiting list during COVID developed RPA of the hip with 40% having femoral head collapse and 21% progressing to acetabular erosion leading to a complex case-mix. Patients on long waiting lists need regular x-ray checks/PROMS since significant proportion progress to FC and Acetabular Erosion

In March 2020, the World Health Organisation declared the COVID-19 outbreak a pandemic. Multiple new guidelines were proposed and existing models of social, domestic and hospital care altered. Most healthcare systems were largely unprepared for this and this pandemic has tested their adaptability. This study is aimed at assessing the impact of covid-19 on the demographics, presentation and clinical management of patients with proximal femoral (hip) fractures. This retrospective multi-centre cohort study compared all patients admitted with hip fractures, between 1. st. March and 30th May 2019 (Group PC: Pre-Covid) with hip fracture patients admitted over the same time period during the pandemic in 2020 (Group C: Covid). The data was obtained from the hospitals' local and National Hip Fracture Databases. Mortality data was checked with the Office for National Statistics (ONS). Primary outcomes were time to theatre, in-patient length of stay and 30-day mortality. 580 patients were included (304 PC, 276 C). Patient Charlson comorbidity index and Nottingham Hip Fracture scores were broadly similar across the two cohorts. There was a significant reduction in percentage of total hip replacements in Group C (11% to 5%, p=0.006). There was an increase in conservative management in group C (1% to 5%, p=0.002). The time to theatre was significantly delayed in Group C (43.7 hours C versus 34.6 hours PC, p<0.001). Overall length of hospital stay was similar in both groups (16.6 days PC versus 15 days C, p=0.089). 30-day mortality rate in Group C was 9.8% compared to 8.2% in Group PC (p=0.431), but for covid (+) patients it was significantly higher at 38.2% versus 5.8% in covid (−) patients (p<0.001). This is one of the largest multi-centre comparative cohort study in the literature to date, examining the impact of the covid-19 pandemic on the management of hip fracture patients. Whilst mortality rates were similar in both groups, covid patients were almost seven times more likely to die, reflecting the seriousness of the covid-19 infection and its sequelae in such elderly, vulnerable patients

Object. The aim of this study was to investigate the impact of the COVID-19 pandemic on the management and outcome of patients with neck of femur fractures. Methods. Data was collected for 96 patients with neck of femur fractures who presented to the emergency department between March 1, 2020 and May 15, 2020. This data set included information about their COVID-19 status. Parameters including inpatient complications, hospital quality measures, mortality rates, and training opportunities were compared between the COVID-19 positive and COVID-19 negative groups. Furthermore, our current cohort of patients were compared against a historical control group of 95 patients who presented with neck of femur fractures before the COVID-19 pandemic. Results. Seven (7.3%) patients were confirmed COVID positive by RT-PCR testing. The COVID positive cohort, when compared to the COVID negative cohort, had higher rates of postoperative complications (71.4% vs 25.9%), increased length of stay (30.3 days vs 12 days) and quicker time to surgery (0.7 days vs 1.3 days). The 2020 cohort compared to the 2019 cohort, had an increased 30-day mortality rate (13.5% vs 4.2%), increased number of delayed cases (25% vs 11.8%) as well as reduced training opportunities for Orthopaedic trainees to perform the surgery (51.6% vs 22.8%). Conclusions. COVID-19 has had a profound impact on the care and outcome of neck of femur fracture patients during the pandemic with an increase in 30-day mortality rate. There were profound adverse effects on patient management pathways and outcomes while also affecting training opportunities

Introduction. Methoxyflurane can cause hepatotoxicity and nephrotoxicity at anaesthetic doses but has excellent analgesic properties and no nephrotoxic effects in patients without preexisting disease. Approved for use in the UK and Ireland in 2015, it is currently being used in emergency departments for analgesia during fracture reduction. During the Covid emergency, with theatre access severely restricted and many patients unwilling to use inhaled Nitrous oxide, Penthrox had the potential to provide adequate pain relief to aid frame removals and minor procedures in the clinic. Materials and Methods. Patients presenting to the Limb Reconstruction Unit Elective clinic and requiring frame removal or minor procedures were included in the study. Patients with renal, cardiac or hepatic disease, history of sensitivity to fluorinated anaesthetic agents and those on any nephrotoxic or enzyme inducing drugs were excluded. Verbal consent was obtained, the risks and benefits explained and the procedure was done in a side room in the clinic. Besides patient and procedure details, the Visual Analog Score and Richmond Agitation Scale was noted and patient's satisfaction documented. The results were presented as numbers, means and averages. Results. A total of 39 patients were included in the study of which 17 had Ilizarov frames removed, 10 had Hexapod Removals, 9 had heel rings removed and 3 others had an ex fix removed. Eleven patients required/ requested extra pain relief in the form of oral analgesia. All patients were satisfied or very satisfied with the experience. One patient had a wire jam during removal and required a GA for removal. Conclusions. Patient satisfaction was very high (>95%) with good results and allowed frame removals and minor procedures to be done in the clinic during the Covid pandemic. It also cut expenses and has potential for regular future use

There has been a significant increase in the demand for arthroplasty as a result of the Covid 19 pandemic and lack of beds on the green pathway. The average length of in-hospital stay following knee replacements has been successfully reduced over the years following introduction and adoption of enhanced recovery protocols. Day case arthroplasty has the potential to be efficient as well as cost-effective. We present our day case pathway for elective knee arthroplasty and early results of its adoption at a district general hospital. Our pathway was developed through a multidisciplinary input from surgeons, anaesthetists, physiotherapists, nursing staff, administrative staff, surgical care practitioners and pharmacists. Inclusion criteria were defined to identify patients suitable for cay case arthroplasty. Results of 32 patients who underwent day case partial and total knee replacement at our institution between 2018 to 2022 are presented. 31 out of 32 (97%) were discharged safely on the day of surgery. Patients were discharged at a mean of 7 hours following surgery. There were no re-admissions following discharge. There were no surgical complications at a mean follow-up of 2 years. Patient feedback revealed high levels of satisfaction and that they would recommend the pathway to others. Cost analysis revealed savings towards bed costs. Our early results demonstrate day case knee arthroplasty to be safe and cost effective. With limited resources to tackle the enormous backlog of arthroplasty, it offers the potential to make theatre utilization efficient

Aims. Hip fracture patients are at higher risk of severe COVID-19 illness, and admission into hospital puts them at further risk. We implemented a two-site orthopaedic trauma service, with ‘COVID’ and ‘COVID-free’ hubs, to deliver urgent and infection-controlled trauma care for hip fracture patients, while increasing bed capacity for medical patients during the COVID-19 pandemic. Methods. A vacated private elective surgical centre was repurposed to facilitate a two-site, ‘COVID’ and ‘COVID-free’, hip fracture service. Patients were screened for COVID-19 infection and either kept at our ‘COVID’ site or transferred to our ‘COVID-free’ site. We collected data for 30 days on patient demographics, Clinical Frailty Scale (CFS), Nottingham Hip Fracture Scores (NHFS), time to surgery, COVID-19 status, mortality, and length of stay (LOS). Results. In all, 47 hip fracture patients presented to our service: 12 were admitted to the ‘COVID’ site and 35 to the ‘COVID-free’ site. The ‘COVID’ site cohort were older (mean 86.8 vs 78.5 years, p = 0.0427) and with poorer CFS (p = 0.0147) and NHFS (p = 0.0023) scores. At the ‘COVID-free’ site, mean time to surgery was less (29.8 vs 52.8 hours, p = 0.0146), and mean LOS seemed shorter (8.7 vs 12.6 days, p = 0.0592). No patients tested positive for COVID-19 infection while at the ‘COVID-free’ site. We redirected 74% of our admissions from the base ‘COVID’ site and created 304 inpatient days’ capacity for medical COVID patients. Conclusion. Acquisition of unused elective orthopaedic capacity from the private sector facilitated a two-site trauma service. Patients were treated expeditiously, while successfully achieving strict infection control. We achieved significant gains in medical bed capacity in response to the COVID-19 demand. The authors propose the repurposing of unused elective operating facilities for a two-site ‘COVID’ and ‘COVID-free’ model as a safe and effective way of managing hip fracture patients during the pandemic. Cite this article: Bone Joint Open 2020;1-6:190–197

Aims. The coronavirus disease (COVID)-19 pandemic forced an unprecedented period of challenge to the NHS in the UK where hip fractures in the elderly population are a major public health concern. There are approximately 76,000 hip fractures in the UK each year which make up a substantial proportion of the trauma workload of an average orthopaedic unit. This study aims to assess the impact of the COVID-19 pandemic on hip fracture care service and the emerging lessons to withstand any future outbreaks. Methods. Data were collected retrospectively on 157 hip fractures admitted from March to May 2019 and 2020. The 2020 group was further subdivided into COVID-positive and COVID-negative. Data including the four-hour target, timing to imaging, hours to operation, anaesthetic and operative details, intraoperative complications, postoperative reviews, COVID status, Key Performance Indicators (KPIs), length of stay, postoperative complications, and the 30-day mortality were compiled from computer records and our local National Hip Fracture Database (NHFD) export data. Results. Hip fractures and inpatient falls significantly increased by 61.7% and 7.2% respectively in the 2020 group. A significant difference was found among the three groups regarding anaesthetic preparation time, anaesthetic time, and recovery time. The mortality rate in the 2020 COVID-positive group (36.8%) was significantly higher than both the 2020 COVID-negative and 2019 groups (11.5% and 11.7% respectively). The hospital stay was significantly higher in the COVID-positive group (mean of 24.21 days (SD 19.29)). Conclusion. COVID-19 has had notable effects on the hip fracture care service: hip fracture rates increased significantly. There were inefficiencies in theatre processes for which we have recommended the use of alternate theatres. COVID-19 infection increased the 30-day mortality and hospital stay in hip fractures. More research needs to be done to reduce this risk. Cite this article: Bone Joint Open 2020;1-9:530–540

Abstract. BACKGROUND. Hemi-arthroplasty (HA) as a treatment for fractured neck of femur has slightly increased since 2019 and remarkably after the COVID pandemic. The main drawback of the treatment is ongoing cartilage deterioration that may require revision to THR. OBJECTIVE. This study assessed cartilage surface damage in hip HA by reproducing anatomical motion and loading conditions in a hip simulator. METHODS. Experimental design. HA tests were conducted using porcine acetabula and CoCr femoral heads. Five groups (n=4) were included: a control group comprising natural tissue and four HA groups where the acetabula were paired with metal heads to allow radial clearance (RC) classed as small (RC<0.6mm), large (2mm<RC<4mm), extra-large (4mm<RC), and oversized (RC<−0.6mm). Tests were carried out in an anatomical hip simulator that reproduced a simplified twin peak gait cycle, adapted for porcine hip joints, from the ISO 14242 standard for wear of THR prostheses (peak load of 900N). The test length was 6 hours, with photogrammetry taken at 1-hour intervals. Ringers solution was used as a lubricant. RESULTS. No changes were observed in the control group. However, cartilage surface changes were observed in all hemi-arthroplasty groups. Discolouration on the cartilage surface was noticeable at the posterior-superior part of the acetabulum after 1-hour (extra-large and oversized groups). Damage severity and location were characteristic of each clearance group. Of all the groups, the oversized group showed more significant damage. No labrum separation was seen after the simulation. CONCLUSIONS. These results are relevant to understand the effect of femoral head clearance on cartilage damage risk after HA. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest