Introduction. The mobile-bearing (MB) total knee arthroplasty (TKA) design was introduced with the aim of reducing polyethylene wear and component loosening seen in the fixed-bearing (FB) design. A recent joint registry study has revealed increased risk for all-cause revision, but not revision for infection, in MB-TKA. We used the New Zealand Joint Registry (NZJR) to compare all-cause revision rates, and revision rates for aseptic loosening of MB-TKA compared with fixed bearing (FB) TKA. Methods. All patients who underwent a primary TKA registered in the NZJR between the 1st January 1999 to 31st December 2021 were identified. Analysis compared MB to FB designs, with sub analysis of implants from a single company. We identified 135,707 primary TKAs, with 104,074 (76.7%) FB-TKAs and 31,633 (23.3%) MB-TKAs recorded. We examined all-cause revision rates, reasons for revision and performed survival analyses. Results. For all-comers, MB-TKA had an all-cause revision rate of 0.43/100-component-years (OCY) compared with 0.42/OCY for FB-TKA (p=0.09). The all-cause revision rate was higher for those age < 65 years (MB TKA 0.60/OCY vs. FB-TKA 0.59/OCY) compared to those > 65 years at time of primary TKA (MB-TKA 0.29/OCY vs. FB-TKA 0.32/OCY), however there was no statistically significant difference between implant design in either age group (p=0.16 and p=0.64; respectively). Similarly, there was no difference in revision rates for aseptic loosening between implant designs. Kaplan-Meier survival analysis demonstrates no statistically significant difference in revision-free survival of implants, with both MB-TKA and FB-TKA demonstrating ∼93% revision free survival at 23 years. Conclusions. Both FB- and MB-TKA demonstrated excellent survivorship, with no significant difference in all-cause revision rates or revision for aseptic loosening between implant designs

The aim of this study was to compare the relative performance of total hip replacement constructs and discern if there is substantial variability in performance in currently commonly used prostheses.

All patients who underwent a primary total hip replacement (THR) registered in the NZJR between 1^st January 1999 to June 2020 were identified. Using a noninferiority analysis, the performance of hip prostheses were compared with the best performing contemporary construct. Construct failure was estimated using the 1-Kaplan Meier survival function method to estimate net failure. The difference in failure between the contemporary benchmark and other constructs was examined.

In total 135 432 THR were recorded comprising 1 035 different THR constructs. Notably 328 constructs were used just once. 48 constructs (62 251 THR) had >500 procedures at risk at 3 years post-primary of which 28 were inferior by at least 20% relative risk of which, 10 were inferior by at least 100% relative risk. 16 constructs were identified with >500 procedures at risk at 10 years with 9 inferior by at least 20%, of which one was inferior by >100% relative risk. There were fewer constructs noninferior to the best practice benchmark when we performed analysis by gender. In females at 10 years, from 5 constructs with >500 constructs at risk, 2 were inferior at the 20% margin. In males at 10 years, there were only 2 eligible constructs of which one was inferior at the 20% margin.

We discerned that there is substantial variability in construct performance and at most time points, just over half of constructs are inferior to the best performing construct by at least 20%. These results can facilitate informed decision-making when considering THR surgery.

Multiple joint registries have reported better implant survival for patients aged >75 years undergoing total hip arthroplasty (THA) with cemented implant combinations when compared to hybrid or uncemented implant combinations. However, there is considerable variation within these broad implant categories, and it has therefore been suggested that specific implant combinations should be compared. We analysed the most common contemporary uncemented (Corail/Pinnacle), hybrid (Exeter V40/Trident) and cemented (Exeter V40/Exeter X3) implant combinations in the New Zealand Joint Registry (NZJR) for patients aged >75 years.

All THAs performed using the selected implants in the NZJR for patients aged >75 years between 1999 and 2018 were included. Demographic data, implant type, and outcome data including implant survival, reason for revision, and post-operative Oxford Hip Scores were obtained from the NZJR, and detailed survival analyses were performed. Primary outcome was revision for any reason. Reason for revision, including femoral or acetabular failure, and time to revision were recorded.

5427 THAs were included. There were 1105 implantations in the uncemented implant combination group, 3040 in the hybrid implant combination group and 1282 in the cemented implant combination group. Patient reported outcomes were comparable across all groups. Revision rates were comparable between the cemented implant combination (0.31 revisions/100 component years) and the hybrid implant combination (0.40 revisions/100 component years) but were statistically significantly higher in the uncemented implant combination (0.80/100 component years). Femoral-sided revisions were significantly greater in the uncemented implant combination group.

The cemented implant and hybrid implant combinations provide equivalent survival and functional outcomes in patients aged over 75 years. Caution is advised if considering use of the uncemented implant combination in this age group, predominantly due to a higher risk of femoral sided revisions. The authors recommend comparison of individual implants rather than broad categories of implants.

Background

Post-operative periprosthetic femoral fractures (PFF) are a devastating complication associated with high mortality and are costly. Few risk factors are modifiable apart from implant choice. The design features governing risk of PFF are unknown. We estimated the 90-day risk of revision for PFF associated with design features of cementless femoral stems and to investigate the effect of a collar on early PFF risk using a biomechanical in-vitro model.

A long surgical procedure length has been well associated with worse clinical outcomes, also in an economic climate where in the theatre, time is money, surgical procedures are done very rapidly. Few studies have documented the clinical outcomes of procedure speed.

Using the New Zealand Registry we reviewed the operation time of 41,560 primary knee joint replacements. These were split into groups of time slots for the surgery from less than 40 minutes, 40–59, 60–89, 90–119, 120–179 and greater than 180mins. This was referenced to the oxford knee scores obtained and the revision rate.

For operations done in less than 40 or greater than 180 minutes, the oxford knee score was lower by 5 years. The revision rate was also increased in these same groups.

Operations done in greater than 180 minutes are generally the more complex non-osteoarthrtic and tumour cases and have a higher revision rate reflecting their complexity. Procedures done less than 40 minutes are more straight forward, but there is a relationship shown between this speed and revision rate and poorer outcome. The cause is likely multifactorial, but begs the question, does speed kill?

Aims. The aim of this study was to report patient and clinical outcomes following robotic-assisted total knee arthroplasty (RA-TKA) at multiple institutions with a minimum two-year follow-up. Methods. This was a multicentre registry study from October 2016 to June 2021 that included 861 primary RA-TKA patients who completed at least one pre- and postoperative patient-reported outcome measure (PROM) questionnaire, including Forgotten Joint Score (FJS), Knee Injury and Osteoarthritis Outcomes Score for Joint Replacement (KOOS JR), and pain out of 100 points. The mean age was 67 years (35 to 86), 452 were male (53%), mean BMI was 31.5 kg/m. 2. (19 to 58), and 553 (64%) cemented and 308 (36%) cementless implants. Results. There were significant improvements in PROMs over time between preoperative, one- to two-year, and > two-year follow-up, with a mean FJS of 17.5 (SD 18.2), 70.2 (SD 27.8), and 76.7 (SD 25.8; p < 0.001); mean KOOS JR of 51.6 (SD 11.5), 85.1 (SD 13.8), and 87.9 (SD 13.0; p < 0.001); and mean pain scores of 65.7 (SD 20.4), 13.0 (SD 19.1), and 11.3 (SD 19.9; p < 0.001), respectively. There were eight superficial infections (0.9%) and four revisions (0.5%). Conclusion. RA-TKA demonstrated consistent clinical results across multiple institutions with excellent PROMs that continued to improve over time. With the ability to achieve target alignment in the coronal, axial, and sagittal planes and provide intraoperative real-time data to obtain balanced gaps, RA-TKA demonstrated excellent clinical outcomes and PROMs in this patient population. Cite this article: Bone Jt Open 2022;3(7):589–595

Aims. The aim of this study was to perform a systematic review and bias evaluation of the current literature to create an overview of risk factors for re-revision following revision total knee arthroplasty (rTKA). Methods. A systematic search of MEDLINE and Embase was completed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The studies were required to include a population of index rTKAs. Primary or secondary outcomes had to be re-revision. The association between preoperative factors and the effect on the risk for re-revision was also required to be reported by the studies. Results. The search yielded 4,847 studies, of which 15 were included. A majority of the studies were retrospective cohorts or registry studies. In total, 26 significant risk factors for re-revision were identified. Of these, the following risk factors were consistent across multiple studies: age at the time of index revision, male sex, index revision being partial revision, and index revision due to infection. Modifiable risk factors were opioid use, BMI > 40 kg/m. 2. , and anaemia. History of one-stage revision due to infection was associated with the highest risk of re-revision. Conclusion. Overall, 26 risk factors have been associated with an increased risk of re-revision following rTKA. However, various levels of methodological bias were found in the studies. Future studies should ensure valid comparisons by including patients with identical indications and using clear definitions for accurate assessments. Cite this article: Bone Jt Open 2024;5(8):644–651

Obesity is a known risk factor for hip osteoarthritis. The aim of this study was to compare the incidence of obesity in Australians undergoing hip replacements (HR) for osteoarthritis to the general population. A cohort study was conducted comparing data from the Australian Bureau of Statistics and the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) from 2017-18. Body mass index (BMI) data for patients undergoing primary total hip replacement and resurfacing for osteoarthritis were obtained from the AOANJRR. The distribution of HR patients by BMI category was compared to the general population, in age and sex sub-groups. During the study period, 32,495 primary HR were performed for osteoarthritis in Australia. Compared to the general population, there was a higher incidence of Class I, II, and III obesity in patients undergoing HR in both sexes aged 35 to 74 years old. Class III obese females and males undergoing HR were on average 6 to 7 years younger than their normal weight counterparts. Class III obese females and males aged 55-64 years old were 2.9 and 1.7 times more likely to undergo HR, respectively (p<0.001). There is a strong association between increased BMI and relative risk of undergoing HR. Similar findings have been noted in the United States of America, Canada, United Kingdom, Sweden and Spain. A New Zealand Registry study and recent meta-analysis have also found a concerning trend of Class III obese patients undergoing HR at a younger age. Obese Australians are at increased risk of undergoing HR at a younger age. A national approach to address the prevalence of obesity is needed

Aim. To date, the value of culture results after a debridement, antibiotics and implant retention (DAIR) for early (suspected) prosthetic joint infection (PJI) as risk indicators in terms of prosthesis retention is not clear. At one year follow-up, the relative risk of prosthesis removal was determined for culture-positive and culture-negative DAIRs after primary total hip or knee arthroplasty. The secondary aim was to explore differences in patient characteristics, infection characteristics and outcomes between these two groups. Methods. A retrospective regional registry study was performed in a group of 359 patients (positive cultures: n = 299, negative cultures n = 60) undergoing DAIR for high suspicion of early PJI in the period from 2014 to 2019. Differences in patient characteristics, deceased patients and number of subsequent DAIRs between the positive and negative DAIR groups were analyzed using independent t-tests, Mann-Whitney, Pearson's Chi-square tests and Fisher's Exact tests. Results. Overall implant survival rate following DAIR was 89%. The relative risk for prosthesis removal was 7.4 times higher (95% confidence interval (CI) 1.0–53.1) in the positive DAIR group (37/299, 12.4%) compared to the negative DAIR group (1/60, 1.7%). The positive group had a higher body mass index (p = 0.034), rate of wound leakage of >10 days (p = 0.016) and more subsequent DAIRs (p = 0.006). Conclusion. Since implant survival results after DAIR are favorable, the threshold to perform a DAIR procedure in early PJI should be low in order to retain the prosthesis. A DAIR procedure in case of negative cultures does not seem to have unfavorable results in terms of prosthesis retention

The benefit of using acetabular screws in primary total hip arthroplasty (THA) has been questioned in recent years. The disadvantages of using screws include increased operative time, risk of injury to surrounding neurovascular structures and metal ware breakage. Recent large registry studies have reported that screws do not confer a protective effect against acetabular loosening or the presence of osteolysis. Other studies have even described an increased risk of aseptic acetabular loosening with the selective use of screws. We report findings from a multicentre cohort study. This large cohort study compared clinical outcomes between primary acetabular components that were inserted with and without screws. Independent variables included the presence (or absence) of screws, the total number of screws used and the cumulative screw length (CSL). Outcome measures included all-cause revision, acetabular component revision and acetabular component loosening. Statistical software (Stata/IC 13.1 for Mac [64-bit Intel]) was used to conduct all statistical analyses. A p-value < 0 .05 taken to be significant. There were 4,583 THAs performed in total. Screws were used in 15.9% (n=733). At a mean follow-up of 5.2 years, the all-cause revision rate in the screw cohort was 1.5% compared to 0.83% in the no screw cohort (p=0.085). There was no difference in acetabular component revision rates for screws (3/733, 0.41%) versus no screws (12/3,850, 0.31%) (p=0.439). The rate of acetabular loosening noted during the time of revision surgery was significantly higher when screws were used in the index procedure (2/733, 0.2%) compared to the no screw cohort (1/3,850, 0.02%) (p=0.017). There was no difference in outcomes when stratifying by the number of screws used or the cumulative screw length. Primary acetabular components do not require screws for fixation. All cause revision rates and acetabular component revision rates are comparable for the screw and the no screw cohorts. The rate of acetabular component loosening, as observed during revision surgery, is significantly higher when screws are used in the index total hip replacement

Aims. Early detection of developmental dysplasia of the hip (DDH) is associated with improved outcomes of conservative treatment. Therefore, we aimed to evaluate a novel screening programme that included both the primary risk factors of breech presentation and family history, and the secondary risk factors of oligohydramnios and foot deformities. Methods. A five-year prospective registry study investigating every live birth in the study’s catchment area (n = 27,731), all of whom underwent screening for risk factors and examination at the newborn and six- to eight-week neonatal examination and review. DDH was diagnosed using ultrasonography and the Graf classification system, defined as grade IIb or above or rapidly regressing IIa disease (≥4. o. at four weeks follow-up). Multivariate odds ratios were calculated to establish significant association, and risk differences were calculated to provide quantifiable risk increase with DDH, positive predictive value was used as a measure of predictive efficacy. The cost-effectiveness of using these risk factors to predict DDH was evaluated using NHS tariffs (January 2021). Results. The prevalence of DDH that required treatment within our population was 5/1,000 live births. The rate of missed presentation of DDH was 0.43/1000 live births. Breech position, family history, oligohydramnios, and foot deformities demonstrated significant association with DDH (p < 0.0001). The presence of breech presentation increased the risk of DDH by 1.69% (95% confidence interval (CI) 0.93% to 2.45%), family history by 3.57% (95% CI 2.06% to 5.09%), foot deformities by 8.95% (95% CI 4.81% to 13.1%), and oligohydramnios nby 11.6% (95 % CI 3.0% to 19.0%). Primary risk factors family history and breech presentation demonstrated an estimated cost-per-case detection of £6,276 and £11,409, respectively. Oligohydramnios and foot deformities demonstrated a cost-per-case detected less than the cost of primary risk factors of £2,260 and £2,670, respectively. Conclusion. The inclusion of secondary risk factors within a national screening programme was clinically successful as they were more cost and resource-efficient predictors of DDH than primary risk factors, suggesting they should be considered in the national guidance. Cite this article: Bone Jt Open 2023;4(4):234–240

Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian Registry Study where 68447 patients were identified for having a hip hemiarthroplasty from 2012-2020. This is a retrospective cohort study, identifying patients that had cementless or cemented hip hemiarthroplasty. The surgeons who performed the procedures were linked to the procedure Total Hip Replacement. Individuals were categorized as experienced hip surgeons or not based on whether they performed 50 hip replacements a year. Identifying high volume surgeon (>50 cases/year) and low volume (<50 cases/year) surgeons. Hazard ratios adjusted for age and sex were performed for risk of revision over this 8-year span. A p-value <0.05 was deemed significant. For high volume surgeons, cementless fixation had a higher revision risk than cemented fixation, HR 1.29 (1.05-1.56), p=0.017. This pattern was similar for low volume surgeons, with cementless fixation having a higher revision risk than cemented fixation, HR 1.37 (1.11-1.70) p=0.004 We could not detect a difference in revision risk for cemented fixation between low volume and high volume surgeons; at 0-1.5 years the HR was 0.96 (0.72-1.28) p=0.786, and at 1.5+ years the HR was 1.61 (0.83-3.11) p=0.159. Similarly, we could not detect a difference in revision risk for cementless fixation between low volume and high volume surgeons, HR 1.11 (0.96-1.29) p=0.161. Using large registry data, cemented hip hemiarthroplasty has a significant lower revision rate than the use of cementless stems even when surgeons are stratified to high and low volume. Low volume surgeons who use uncemented prostheses have the highest rate of revision. The low volume hip surgeon who cements has a lower revision rate than the high volume cementless surgeon. The results of this study should help to guide surgeons that no matter the level of experience, using a cemented hip hemiarthroplasty for acute femoral neck fracture is the safest option. That high volume surgeons who perform cementless hemiarthroplasty are not immune to having revisions due to their technique. Increased training and education should be offered to surgeons to improve comfort when using this technique

Recent registry data from around the world has strongly suggested that using cemented hip hemiarthroplasty has lower revision rates compared to cementless hip hemiarthroplasty for acute femoral neck hip fractures. The adoption of using cemented hemiarthroplasty for hip fracture has been slow as many surgeons continue to use uncemented stems. One of the reasons is that surgeons feel more comfortable with uncemented hemiarthroplasty as they have used it routinely. The purpose of this study is to compare the difference in revision rates of cemented and cementless hemiarthroplasty and stratify the risk by surgeon experience. By using a surgeons annual volume of Total Hip Replacements performed as an indicator for surgeon experience. The Canadian Joint Replacement Registry Database was used to collect and compare the outcomes to report on the revision rates based on surgeon volume. This is a large Canadian Registry Study where 68447 patients were identified for having a hip hemiarthroplasty from 2012-2020. This is a retrospective cohort study, identifying patients that had cementless or cemented hip hemiarthroplasty. The surgeons who performed the procedures were linked to the procedure Total Hip Replacement. Individuals were categorized as experienced hip surgeons or not based on whether they performed 50 hip replacements a year. Identifying high volume surgeon (>50 cases/year) and low volume (<50 cases/year) surgeons. Hazard ratios adjusted for age and sex were performed for risk of revision over this 8-year span. A p-value <0.05 was deemed significant. For high volume surgeons, cementless fixation had a higher revision risk than cemented fixation, HR 1.29 (1.05-1.56), p=0.017. This pattern was similar for low volume surgeons, with cementless fixation having a higher revision risk than cemented fixation, HR 1.37 (1.11-1.70) p=0.004 We could not detect a difference in revision risk for cemented fixation between low volume and high volume surgeons; at 0-1.5 years the HR was 0.96 (0.72-1.28) p=0.786, and at 1.5+ years the HR was 1.61 (0.83-3.11) p=0.159. Similarly, we could not detect a difference in revision risk for cementless fixation between low volume and high volume surgeons, HR 1.11 (0.96-1.29) p=0.161. Using large registry data, cemented hip hemiarthroplasty has a significant lower revision rate than the use of cementless stems even when surgeons are stratified to high and low volume. Low volume surgeons who use uncemented prostheses have the highest rate of revision. The low volume hip surgeon who cements has a lower revision rate than the high volume cementless surgeon. The results of this study should help to guide surgeons that no matter the level of experience, using a cemented hip hemiarthroplasty for acute femoral neck fracture is the safest option. That high volume surgeons who perform cementless hemiarthroplasty are not immune to having revisions due to their technique. Increased training and education should be offered to surgeons to improve comfort when using this technique

Aims. The aim of our study was to investigate the effect of asymmetric crosslinked polyethylene liner use on the risk of revision of cementless and hybrid total hip arthroplasties (THAs). Methods. We undertook a registry study combining the National Joint Registry dataset with polyethylene manufacturing characteristics as supplied by the manufacturers. The primary endpoint was revision for any reason. We performed further analyses on other reasons including instability, aseptic loosening, wear, and liner dissociation. The primary analytic approach was Cox proportional hazard regression. Results. A total of 213,146 THAs were included in the analysis. Overall, 2,997 revisions were recorded, 1,569 in THAs with a flat liner and 1,428 in THAs using an asymmetric liner. Flat liner THAs had a higher risk of revision for any reason than asymmetric liner THAs when implanted through a Hardinge/anterolateral approach (hazard ratio (HR) 1.169, 95% confidence interval (CI) 1.022 to 1.337) and through a posterior approach (HR 1.122, 95% CI 1.108 to 1.346). There was no increased risk of revision for aseptic loosening when asymmetric liners were used for any surgical approach. A separate analysis of the three most frequently used crosslinked polyethylene liners was in agreement with this finding. When analyzing THAs with flat liners only, THAs implanted through a Hardinge/anterolateral approach were associated with a reduced risk of revision for instability compared to posterior approach THAs (HR 0.561 (95% CI 0.446 to 0.706)). When analyzing THAs with an asymmetric liner, there was no significant difference in the risk of revision for instability between the two approaches (HR 0.838 (95% CI 0.633 to 1.110)). Conclusion. For THAs implanted through the posterior approach, the use of asymmetric liners reduces the risk of revision for instability and revision for any reason. In THAs implanted through a Hardinge/anterolateral approach, the use of an asymmetric liner was associated with a reduced risk of revision. The effect on revision for instability was less pronounced than in the posterior approach. Cite this article: Bone Joint J 2021;103-B(9):1479–1487

Special acetabular polyethylene (PE) liners are intended to increase the stability of the artificial hip joint, yet registry studies on them are limited. The pupose of this study was to investigate differences in revision rates for mechanical complications in primary cementless total hip arthroplasty (THA) with standard and special PE acetabular liners in patients with ostheoarthritis. Data from the German Arthroplasty Registry (EPRD) between 2012 until 2020 were analysed. Patients with diagnosed ostheoarthritis of the hip without relevant prior surgeries, who received a primary cementless THA with a ceramic/PE bearing articulation were included. Cumulative incidences of revision for mechanical complications for Standard and 4 special PE liners (Lipped, Increased Offset, Angulated, Angulated|Increased Offset) were determined using the Kaplan-Meier Estimator. Confounding factors were investigated with a Cox proportional-hazards model. In total 151.104 cases were included. 7-year unadjusted revision-free survival for mechanical complications compared to Standard liners (97.7%) was lower for Angulated (97.4%), Lipped (97.2%) and Angulated|Increased Offset liners (94.7%), but higher for Increased Offset liners (98.1%). Risk of revision for mechanical complications was not significantly different between Standard, Lipped and Angulated liners. Increased Offset liners (HR=0.68; 95% CI=0.5–0.92) reduced, while Angulated|Increased Offset liners (HR= 1.81; 95% CI=1.38–2.36) increased the risk. Higher age at admission and an Elixhauser comorbidity index greater zero increased the risk, whereas a larger liner share slightly reduced the risk. Only the use of Increased Offset liners reduced the risk of revision for mechanical complications compared to Standard liners — other special liners did not

Aims. To investigate the effect of polyethylene manufacturing characteristics and irradiation dose on the survival of cemented and reverse hybrid total hip arthroplasties (THAs). Methods. In this registry study, data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man (NJR) were linked with manufacturing data supplied by manufacturers. The primary endpoint was revision of any component. Cox proportional hazard regression was a primary analytic approach adjusting for competing risk of death, patient characteristics, head composition, and stem fixation. Results. A total of 290,770 primary THAs were successfully linked with manufacturing characteristics. Overall 4,708 revisions were analyzed, 1,260 of which were due to aseptic loosening. Total radiation dose was identified as a risk factor and included in the Cox model. For statistical modelling of aseptic loosening, THAs were grouped into three categories: G1 (no radiation); G2 ( > 0 to < 5 Mrad); and G3 ( ≥ 5 Mrad). G1 had the worst survivorship. The Cox regression hazard ratio for revision due to aseptic loosening for G2 was 0.7 (95% confidence interval (CI) 0.58 to 0.83), and for G3 0.4 (95% CI 0.30 to 0.53). Male sex and uncemented stem fixation were associated with higher risk of revision and ceramic heads with lower risk. Conclusion. Polyethylene irradiation was associated with reduced risk of revision for aseptic loosening. Radiation doses of ≥ 5 Mrad were associated with a further reduction in risk. Cite this article: Bone Joint Res 2020;9(9):563–571

Background. The acknowledged benefit of the direct anterior (DA) approach is early functional return. Most surgeons in the U.S. use cementless femoral replacement given the negative track record of some cemented designs. However, delayed osseointegration of a femoral stem typically seen in older patients with poor bone quality will delay recovery, diminishing the benefits of the DA approach. Registry studies have shown a higher revision rate and complications in this patient population leading to a renewed interest in cemented fixation. Questions posed. To achieve the functional benefits of the DA approach and the fixation benefits of cemented replacement, this study combined the 2 techniques posing the following questions:1) Does the limited access of the DA approach adversely affect the cement technique? 2) Does such a cementing technique reduce the incidence of cementless complications?. Methods. A consecutive series of 341 patients (360 hips) receiving the DA approach between 2016–2018 were reviewed. There were 203 cementless stems and 157 cemented stems. Mean age was 75 in the cementless group and 76 in the cemented group, 70% females. Femoral complications were compared between the 2 groups using the T-test. Results. The cementless group had a higher rate of femoral complications (8 versus 0, P=0.011). There were 2 loose stems and 6 fractures, all requiring revision. Fractures occurred about 14.5 days and loosening about 10 months postoperatively. Conclusion. A higher rate of complications occurred with cementless stems. Cemented stems are protective in patients above 70 and can be safely done through the DA approach

Background. The purpose of this study was to report functional outcome scores following arthroscopic acetabular chondral procedures using the U.K. Non-Arthroplasty Hip Registry (NAHR). Methods. Data on adult patients who underwent hip arthroscopy between January 2012 and December 2018 was extracted from the NAHR. Patients who underwent femoral sided chondral procedures were excluded. Patients who underwent osteophyte excision or a concurrent extra-articular procedure were also excluded. Cases were then classified according to the acetabular chondral procedure performed – ‘chondroplasty’, ‘microfracture’ or ‘none’ (no chondral procedure recorded). Outcomes comprised EuroQol-5 Dimensions (EQ-5D) index and the International Hip Outcome Tool 12 (iHOT-12), preoperatively and at 6 and 12 months. Results. A total of 4,978 arthroscopies were identified (chondroplasty 26.4%, microfracture 5.4%, none 68.2%). Patients who underwent microfracture were significantly older (37.9y vs 37.3y) and of higher BMI (26.4 vs 25.8 kg/m2) than patients who underwent chondroplasty. Pre-operative, 6 and 12-month follow-up were available for 77%, 42% and 38% of cases respectively. This registry study found significant clinical improvement in all groups based on arthroscopic chondral procedure following hip arthroscopy. Patients who have microfracture seem to take longer to improve and have lower peak scores as compared with chondroplasty. All groups saw significant (p <0.0001) EQ-5D and iHOT-12 gain compared to pre-operative baseline scores at 6 months which was maintained at 12 months (12 month iHOT-12 gain: chondroplasty = +27.6 (95%CI 25.0 to 30.2), microfracture = +22.6 (95%CI 17.6 to 27.6), none = +25.4 (23.8 to 27.0)). There were no statistically significant between group differences in iHOT-12 gain. Comparing <40y vs >40y age groups, all saw significant improvements in baseline scores maintained up to 12 months however patients over 40y were slower to improve, particularly in microfracture with significantly poorer iHOT-12 gain at 6 months in comparison to patients under 40y but significance was lost by 12 months. Conclusion. Whilst patient selection is crucial (and we acknowledge selection bias as a key limitation), all three chondral procedures were effective at improving patient outcomes for both younger and older patients

Cemented acetabular components commonly have a long posterior wall (LPW). Alternative components have a hooded or offset reorientating geometry, theoretically to reduce the risk of THR instability. We aimed to determine if cemented acetabular component geometry influences the risk of revision surgery for instability or loosening. The National Joint Registry for England, Wales and Northern Ireland (NJR) dataset was analysed for primary THAs performed between 2003 – 2017. A cohort of 224,874 cemented acetabular components were identified. The effect of acetabular component geometry on the risk of revision for instability or for loosening was investigated using binomial regression adjusting for age, gender, ASA grade, diagnosis, side, institution type, operating surgeon grade, surgical approach, polyethylene crosslinking and head size. A competing risk survival analysis was performed with the competing risks being revision for other indications or death. Among the cohort of subjects included, the distribution of acetabular component geometries was: LPW – 81.2%, hooded – 18.7% and offset reorientating – 0.1%. There were 3,313 (1.47%) revision THAs performed, of which 815 (0.36%) were for instability and 838 (0.37%) were for loosening. Compared to the LPW group, the adjusted subhazard ratio of revision for instability in the hooded group was 2.29 (p<0.001) and 4.12 (p=0.047) in the offset reorientating group. Likewise, the subhazard ratio of revision for loosening was 2.43 (p<0.001) in the hooded group and 11.47 (p<0.001) in the offset reorientating group. A time-varying subhazard ratio of revision for instability (hooded vs LPW) was found, being greatest within the first 6 months. This Registry based study confirms a significantly higher risk of revision THA for instability and for loosening when a cemented hooded or offset reorientating acetabular component is used, compared to an LPW component. Further research is required to clarify if certain patients benefit from the use of hooded or offset reorientating components, but we recommend caution when using such components in routine clinical practice

The protective effect of lipped polyethylene uncemented acetabular liners against revision THA for instability has been reported. However, the effect of lip size has not been explored, nor has the effect on revision THA for loosening. We aimed to determine if uncemented acetabular liner geometry, and lip size, influences the risk of revision THA for instability or loosening. 202511 primary THAs with uncemented polyethylene acetabular components were identified from the NJR dataset (2003 – 2017). The effect of acetabular liner geometry and lip size on the risk of revision THA for instability or loosening was investigated using binomial regression and competing risks survival analyses (competing risks were revision for other causes or death) adjusting for age, gender, ASA grade, diagnosis, side, institution type, surgeon grade, surgical approach, head size and polyethylene crosslinking. The distribution of acetabular liners was: neutral – 39.4%, offset neutral – 0.9%, 10-degree – 34.5%, 15-degree – 21.6%, 20-degree – 0.8%, offset reorientating – 2.82%. There were 690 (0.34%) revision THAs for instability and 604 (0.3%) for loosening. Significant subhazard risk ratios were found in revision THA for instability with 10-degree (0.63), 15-degree (0.48) and offset reorientating (1.6) liners, compared to neutral liners. There was no association found between liner geometry and risk of revision THA for loosening. This Registry based study confirms a significantly lower risk of revision THA for instability when a lipped liner is used, compared to neutral liners, and a higher risk with the use of offset reorientating liners. Furthermore, 15degree liners seem to have a lower risk than 10degree liners. We did not find an association between acetabular liner geometry and revision THA for loosening. 10- and 15-degree lipped polyethylene liners seem to offer a lower revision risk over neutral liners, at least at medium term followup. Further studies are required to confirm if this benefit continues into the long-term