Aims. The aims of this study were to evaluate the incidence of reoperation (all cause and specifically for periprosthetic femoral fracture (PFF)) and mortality, and associated risk factors, following a hemiarthroplasty incorporating a cemented collarless polished taper slip stem (PTS) for management of an intracapsular hip fracture. Methods. This retrospective study included hip fracture patients aged 50 years and older treated with Exeter (PTS) bipolar hemiarthroplasty between 2019 and 2022. Patient demographics, place of domicile, fracture type, delirium status, American Society of Anesthesiologists (ASA) grade, length of stay, and mortality were collected. Reoperation and mortality were recorded up to a median follow-up of 29.5 months (interquartile range 12 to 51.4). Cox regression was performed to evaluate independent risk factors associated with reoperation and mortality. Results. The cohort consisted of 1,619 patients with a mean age of 82.2 years (50 to 104), of whom 1,100 (67.9%) were female. In total, 29 patients (1.8%) underwent a reoperation; 12 patients (0.7%) sustained a PFF during the observation period (United Classification System (UCS)-A n = 2; UCS-B n = 5; UCS-C n = 5), of whom ten underwent surgical management. Perioperative delirium was independently associated with the occurrence of PFF (hazard ratio (HR) 5.92; p = 0.013) and surgery for UCS-B PFF (HR 21.7; p = 0.022). Neither all-cause reoperation nor PFF-related surgery was independently associated with mortality (HR 0.66; p = 0.217 and HR 0.38; p = 0.170, respectively). Perioperative delirium, male sex, older age, higher ASA grade, and pre-fracture residential status were independently associated with increased mortality risk following hemiarthroplasty (p < 0.001). Conclusion. The cumulative incidence of PFF at four years was 1.1% in elderly patients following cemented PTS hemiarthroplasty for a hip fracture. Perioperative delirium was independently associated with a PFF. However, reoperation for PPF was not independently associated with patient mortality after adjusting for patient-specific factors. Cite this article: Bone Jt Open 2024;5(4):269–276

Background. This clinical study aims to establish the rate of operative inadvertent hypothermia (IH) in elderly hip fracture patients (>65 years old). We postulate that differences exist in risk factors and hypothesised poorer outcomes in patients with IH. Methods. A single centre, retrospective study of 929 hip fracture patients managed operatively between June 2015 and July 2017 was conducted. Patients’ demographic, anaesthetic and surgical variables were analysed together with outcomes for length of stay (LOS), 30-day re-admissions, and 30-day mortality. Results. Overall rates of IH in elderly hip fracture patients undergoing surgery were 10%, with increasing age as a risk factor (p = 0.005). There was trend towards IH in patients receiving sliding hip screw (SHS) (p = 0.079). No difference in LOS was observed between IH and normothermic patients (8.9 ± 7.1 versus 8.6 ± 4.9, p= 0.51). 30-day re-admissions were 18.5% for IH patients versus 7.8% in normothermic patients (p<0.001). There was a trend towards a higher 30-day mortality (p = 0.089), and a significantly higher mortality in IH patients undergoing SHS (p = 0.014). Conclusion. Rates of IH are high in operatively managed hip fracture patients. IH is significantly associated with a higher 30-day readmission rate with a trend towards higher 30-day mortality. This study mandates an examination of strategies for maintaining normothermia in operatively managed elderly hip fracture patients

This review summarises the evidence for the treatment of displaced fractures of the femoral neck in elderly patients. Results from randomised clinical trials and national register studies are presented when available. . The advantages of arthroplasty compared with internal fixation are supported by several studies. A number of studies contribute to the discussions of total hip arthroplasty (THA) versus hemiarthroplasty and unipolar versus bipolar hemiarthroplasty, but no clear-cut evidence-based recommendation can be made. THA may be particularly advantageous for active, lucid patients with a relatively long life expectancy. For patients who are physiologically older, hemiarthoplasty is probably satisfactory, and for the oldest patients with more comorbidities, unipolar implants are considered to be sufficient. If the hospital can support emergency THA surgery in sufficient numbers and quality, there may be few patients who warrant bipolar hemiarthroplasty. . The direct lateral approach reduces the risk of dislocation compared with the posterior approach. Cemented implants lower the risk of periprosthetic fracture and its subsequent morbidity and mortality. As the risk of peri-operative death related to bone cement can be reduced by adequate measures, cemented implants are recommended in fracture cases. Take home message: There remains a great variation in the surgical management of patients with a hip fracture, and an evidence-based approach should improve the outcomes for this vulnerable patient group. Cite this article: Bone Joint J 2016;98-B:291–7

Aims

“Get It Right First Time” (GIRFT) and NHS England’s Best Practice Tariff (BPT) have published directives advising that patients over the ages of 65 (GIRFT) and 69 years (BPT) receiving total hip arthroplasty (THA) should receive cemented implants and have brought in financial penalties if this policy is not observed. Despite this, worldwide, uncemented component use has increased, a situation described as a ‘paradox’. GIRFT and BPT do, however, acknowledge more data are required to support this edict with current policies based on the National Joint Registry survivorship and implant costs.

Aims

Our primary aim was to assess reoperation-free survival at one year after the index injury in patients aged ≥ 75 years treated with internal fixation (IF) or arthroplasty for undisplaced femoral neck fractures (uFNFs). Secondary outcomes were reoperations and mortality analyzed separately.

Aims

To develop prediction models using machine-learning (ML) algorithms for 90-day and one-year mortality prediction in femoral neck fracture (FNF) patients aged 50 years or older based on the Hip fracture Evaluation with Alternatives of Total Hip arthroplasty versus Hemiarthroplasty (HEALTH) and Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trials.

The best treatment for the active and lucid elderly patient with a displaced intracapsular fracture of the femoral neck is still controversial. Randomised controlled trials have shown that a primary total hip replacement is superior to internal fixation as regards the need for secondary surgery, hip function and health-related quality of life. Despite good results achieved with total hip replacement in this group, most orthopaedic surgeons still advocate hemiarthroplasty for this injury. We studied 120 patients with a mean age of 81 years (70 to 90) with an acute displaced intracapsular fracture of the femoral neck. They were randomly allocated to be treated with either a bipolar hemiarthroplasty or total hip replacement. Outcome measurements included peri-operative data, general and hip-specific complications, hip function and health-related quality of life. The patients were reviewed at four and 12 months. The duration of surgery was longer in the total hip replacement group (102 minutes (70 to 151)) versus 78 minutes (43 to 131) (p < 0.001), and the intra-operative blood loss was increased 460 ml (100 to 1100) versus 320 ml (50 to 850) (p < 0.001), but there were no differences between the groups regarding any complications or mortality. There were no dislocations in either group. Hip function measured by the Harris hip score was significantly better in the total hip replacement group at both follow-up periods (p = 0.011 and p < 0.001, respectively). The health-related quality of life measure was in favour of the total hip replacement group but did not reach statistical significance (p = 0.818 at four months and p = 0.636 at 12 months). These results indicate that a total hip replacement provides better function than a bipolar hemiarthroplasty as soon as one year post-operatively, without increasing the complication rate. We recommend total hip replacement as the primary treatment for this group of patients

Aims

The aim of this study was to compare the rate of perioperative complications following aseptic revision total hip arthroplasty (THA) in patients aged ≥ 80 years with that in those aged < 80 years, and to identify risk factors for the incidence of serious adverse events in those aged ≥ 80 years using a large validated national database.

The treatment algorithms for displaced fractures of the femoral neck need to be improved if we are to reduce the need for secondary surgery. We have studied 102 patients of mean age 80 years, with an acute displaced fracture of the femoral neck. They were randomly placed into two groups, treated either by internal fixation (IF) with two cannulated screws or total hip replacement (THR). None showed severe cognitive dysfunction, all were able to walk independently, and all lived in their own home. They were reviewed at four, 12 and 24 months after surgery. Outcome measurements included hip complications, revision surgery, hip function according to Charnley and the health-related quality of life (HRQoL) according to EuroQol (EQ-5D). The failure rate after 24 months was higher in the IF group than in the THR group with regard to hip complications (36% and 4%, respectively; p < 0.001), and the number of revision procedures (42% and 4%, p < 0.001). Hip function was significantly better in the THR group at all follow-up reviews regarding pain (p < 0.005), movement (p < 0.05 except at 4 months) and walking (p < 0.05). The reduction in HRQoL (EQ-5D . index. score) was also significantly lower in the THR group than in the IF group, comparing the pre-fracture situation with that at all follow-up reviews (p < 0.05). The results of our study strongly suggest that THR provides a better outcome than IF for elderly, relatively healthy, lucid patients with a displaced fracture of the femoral neck

Introduction

Patients with pre-existing dementia are more susceptible to hip fracture due to various risk factors such as age, decreased activity leading to sarcopenia and osteoporosis, Vitamin D deficiency and presence of Apolipoprotein gene. The mortality associated with dementia and fracture neck of femurs was thought to be 2.3 times more than that of patients with intact cognitive function. The aim of this study is to assess the mortality of patients at 28 days, 4 months and one year after undergoing surgery for fracture neck of femurs.

Aims. To describe the epidemiology of acetabular fractures including patient characteristics, injury mechanisms, fracture patterns, treatment, and mortality. Methods. We retrieved information from the Swedish Fracture Register (SFR) on all patients with acetabular fractures, of the native hip joint in the adult skeleton, sustained between 2014 and 2020. Study variables included patient age, sex, injury date, injury mechanism, fracture classification, treatment, and mortality. Results. In total, 2,132 patients with acetabular fractures from the SFR were included in the study. The majority of the patients were male (62%) and aged over 70 years old (62%). For patients aged > 70 years, the 30-day mortality was 8% and one-year mortality 24%. For patients aged ≤ 70 years, the 30-day mortality was 0.2% and one-year mortality 2%. Low-energy injuries (63%) and anterior wall fractures (20%) were most common. Treatment was most often non-surgical (75%). Conclusion. The majority of patients who sustain an acetabular fracture are elderly (> 70 years), of male sex, and the fracture most commonly occurs after a simple, low-energy fall. Non-surgical treatment is chosen in the majority of acetabular fracture patients. The one-year mortality for elderly patients with acetabular fracture is similar to the mortality after hip fracture, and a similar multidisciplinary approach to care for these patients should be considered. Cite this article: Bone Jt Open 2023;4(9):652–658

Aims. This work aimed at answering the following research questions: 1) What is the rate of mechanical complications, nonunion and infection for head/neck femoral fractures, intertrochanteric fractures, and subtrochanteric fractures in the elderly USA population? and 2) Which factors influence adverse outcomes?. Methods. Proximal femoral fractures occurred between 1 January 2009 and 31 December 2019 were identified from the Medicare Physician Service Records Data Base. The Kaplan-Meier method with Fine and Gray sub-distribution adaptation was used to determine rates for nonunion, infection, and mechanical complications. Semiparametric Cox regression model was applied incorporating 23 measures as covariates to identify risk factors. Results. Union failure occured in 0.89% (95% confidence interval (CI) 0.83 to 0.95) after head/neck fracturs, in 0.92% (95% CI 0.84 to 1.01) after intertrochanteric fracture and in 1.99% (95% CI 1.69 to 2.33) after subtrochanteric fractures within 24 months. A fracture-related infection was more likely to occur after subtrochanteric fractures than after head/neck fractures (1.64% vs 1.59%, hazard ratio (HR) 1.01 (95% CI 0.87 to 1.17); p < 0.001) as well as after intertrochanteric fractures (1.64% vs 1.13%, HR 1.31 (95% CI 1.12 to 1.52); p < 0.001). Anticoagulant use, cerebrovascular disease, a concomitant fracture, diabetes mellitus, hypertension, obesity, open fracture, and rheumatoid disease was identified as risk factors. Mechanical complications after 24 months were most common after head/neck fractures with 3.52% (95% CI 3.41 to 3.64; currently at risk: 48,282). Conclusion. The determination of complication rates for each fracture type can be useful for informed patient-clinician communication. Risk factors for complications could be identified for distinct proximal femur fractures in elderly patients, which are accessible for therapeutical treatment in the management. Cite this article: Bone Jt Open 2023;4(10):801–807

The early revision rate in elective Total Hip Arthroplasty (THA) three years after surgery in elderly patients over 80 years is significantly lower for cemented stems in the German Arthroplasty Register (EPRD): cemented 3,1% (3.0 – 3.2) vs. uncemented 4.2% (4.1 – 4.3; p < 0.001). However, the mortality rate in elderly patients is elevated for cemented fixation. This study presents a detailed analysis of the influence of stem type and fixation on revision and mortality rate in this patient cohort. Elective primary THA cases for primary Coxarthrosis using uncemented cups from the EPRD data base were analysed (n. 0. = 37,183). Four stem type groups were compared: cementless, cementless with collar, cementless short, and cemented. Stems with at least 300 cases at risk three years after surgery were analysed individually. The reference stem was determined as the stem with the lowest revision rate and at least 1000 cases under surveillance 3 years after surgery (n. 3. = 28,637). The revision rate for cemented stems (2.5% [2.2–1.81] was lower than for uncemented (4.5% [4.2–4.9]; p<0.001) and uncemented short stems (4.2% [3.1–5.7]; p=0.002). The revision rate of uncemented collared stems (2.3% [1.5–3.6]) was similar to cemented stems (p=0.89) and lower than for uncemented stems (p=0.02). One year mortality showed no sig. differences between the groups (p>0.17): cemented 3.2% [2.9–3.6], uncemented 3.4% [3.1–3.7], uncemented short 3.5% [2.5–4.9], uncemented collar 2.0% [1.2–3.2]. “Cementless” and “cementless short” stems should not be used in patients over 80 years due to the higher revision risk. If cementing should be avoided, “cementless collared” stems seem to be a good alternative combined with a tendency for a lower one year mortality rate

The incidence of hip fractures in the elderly is increasing. Minimally displaced and un-displaced hip fractures can be treated with either internal fixation or hemiarthroplasty. The aim was identifying the revision rate of internal fixation and hemiarthroplasty in patients 60 years or older with Garden I or II hip fractures and to identify risk factors associated with each method. A retrospective analysis was conducted from 2 Major Trauma Centres and 9 Trauma Units between 01/01/2015 and 31/12/2020. Patients managed conservatively, treated with a total hip replacement and missing data were excluded from the study. 1273 patients were included of which 26.2% (n=334) had cannulated hip fixation (CHF), 19.4% (n=247) had a dynamic hip screw (DHS) and 54.7% (n=692) had a hemiarthroplasty. 66 patients in total (5.2%) required revision surgery. The revision rates for CHF, DHS and hemiarthroplasty were 14.4%, 4%, 1.2% (p<0.001) respectively. Failed fixation was the most common reason for revision with the incidence increasing by 7-fold in the CHF group [45.8% (n=23) vs. 33.3% (n=3) in DHS; p<0.01]. The risk factors identified for CHF revision were age >80 (p<0.05), female gender (p<0.05) and smoking (p<0.05). The average length of hospital stay was decreased when using CHF compared to DHS and hemiarthroplasty (12.6 days vs 14.9 days vs 18.1 days respectively, p<0.001) and the 1 year mortality rate for CHF, DHS and hemiarthroplasty was 2.5%, 2% and 9% respectively. Fixation methods for Garden I and II hip fractures in elderly patients are associated with a higher revision rate than hemiarthroplasty. CHF has the highest revision rate at 14.4% followed by DHS and hemiarthroplasty. Female patients, patients over the age of 80 and patients with poor bone quality are considered high risk for fixation failure with CHF. When considering a fixation method in such patients, DHS is more robust than a screw construct, followed by hemiarthroplasty

Aims. Total hip arthroplasty (THA) is a very successful and cost-effective operation, yet debate continues about the optimum fixation philosophy in different age groups. The concept of the 'cementless paradox' and the UK 'Getting it Right First Time' initiative encourage increased use of cemented fixation due to purported lower revision rates, especially in elderly patients, and decreased cost. Methods. In a high-volume, tertiary referral centre, we identified 10,112 THAs from a prospectively collected database, including 1,699 cemented THAs, 5,782 hybrid THAs, and 2,631 cementless THAs. The endpoint was revision for any reason. Secondary analysis included examination of implant survivorship in patients aged over 70 years, over 75 years, and over 80 years at primary THA. Results. Cemented fixation had the lowest implant survival in all age groups, with a total ten-year survivorship of 97.0% (95% confidence interval (CI) 95.8 to 97.8) in the cemented group, 97.6% (95% CI 96.9 to 98.1) in the hybrid group, and 97.9% (95% CI 96.9 to 98.6) in the cementless group. This was not statistically significant (p = 0.092). There was no age group where cemented fixation outperformed hybrid or cementless fixation. Conclusion. While all fixation techniques performed well at long-term follow-up, cemented fixation was associated with the lowest implant survival in all age groups, including in more elderly patients. We recommend that surgeons should carefully monitor their own outcomes and use fixation techniques that they are familiar with, and deliver the best outcomes in their own hands. Cite this article: Bone Joint J 2022;104-B(2):206–211

Aims. The number of revision arthroplasties being performed in the elderly is expected to rise, including revision for infection. The primary aim of this study was to measure the treatment success rate for octogenarians undergoing revision total hip arthroplasty (THA) for periprosthetic joint infection (PJI) compared to a younger cohort. Secondary outcomes were complications and mortality. Methods. Patients undergoing one- or two-stage revision of a primary THA for PJI between January 2008 and January 2021 were identified. Age, sex, BMI, American Society of Anesthesiologists grade, Charlson Comorbidity Index (CCI), McPherson systemic host grade, and causative organism were collated for all patients. PJI was classified as ‘confirmed’, ‘likely’, or ‘unlikely’ according to the 2021 European Bone and Joint Infection Society criteria. Primary outcomes were complications, reoperation, re-revision, and successful treatment of PJI. A total of 37 patients aged 80 years or older and 120 patients aged under 80 years were identified. The octogenarian group had a significantly lower BMI and significantly higher CCI and McPherson systemic host grades compared to the younger cohort. Results. The majority of patients were planned to undergo two-stage revision, although a significantly higher proportion of the octogenarians did not proceed with the second stage (38.7% (n = 12) vs 14.8% (n = 16); p = 0.003). Although there was some evidence of a lower complication rate in the younger cohort, this did not reach statistical significance (p = 0.065). No significant difference in reoperation (21.6% (n = 8) vs 25.0% (n = 30); p = 0.675) or re-revision rate (8.1% (n = 3) vs 16.7% (n = 20); p = 0.288) was identified between the groups. There was no difference in treatment success between groups (octogenarian 89.2% (n = 33) vs control 82.5% (n = 99); p = 0.444). Conclusion. When compared to a younger cohort, octogenarians did not show a significant difference in complication, re-revision, or treatment success rates. However, given they are less likely to be eligible to proceed with second stage revision, consideration should be given to either single-stage revision or use of an articulated spacer to maximize functional outcomes. Cite this article: Bone Joint J 2024;106-B(8):802–807

Aims. Periprosthetic joint infection (PJI) in total hip arthroplasty in the elderly may occur but has been subject to limited investigation. This study analyzed infection characteristics, surgical outcomes, and perioperative complications of octogenarians undergoing treatment for PJI in a single university-based institution. Methods. We identified 33 patients who underwent treatment for PJIs of the hip between January 2010 and December 2019 using our institutional joint registry. Mean age was 82 years (80 to 90), with 19 females (57%) and a mean BMI of 26 kg/m. 2. (17 to 41). Mean American Society of Anesthesiologists (ASA) grade was 3 (1 to 4) and mean Charlson Comorbidity Index was 6 (4 to 10). Leading pathogens included coagulase-negative Staphylococci (45%) and Enterococcus faecalis (9%). Two-stage exchange was performed in 30 joints and permanent resection arthroplasty in three. Kaplan-Meier survivorship analyses were performed. Mean follow-up was five years (3 to 7). Results. The two-year survivorship free of any recurrent PJI was 72% (95% confidence interval (CI) 56 to 89; 18 patients at risk). There were a total of nine recurrent PJIs at a mean of one year (16 days to eight years), one for the same pathogen as at index infection. One additional surgical site infection was noted at two weeks, resulting in a 69% (95% CI 52 to 86; 17 patients at risk) survivorship free of any infection at two years. There were two additional revisions for dislocations at one month each. As such, the two-year survivorship free of any revision was 61% (95% CI 42 to 80; 12 patients at risk). In addition to the aforementioned revisions, there was one additional skin grafting for a decubitus ulcer, resulting in a survivorship free of any reoperation of 54% (95% CI 35 to 73; ten patients at risk) at two years. Mean Clavien-Dindo score of perioperative complications was two out of five, with one case of perioperative death noted at six days. Conclusion. Octogenarians undergoing surgery for PJI of the hip are at low risk of acute mortality, but are at moderate risk of other perioperative complications. One in two patients will undergo a reoperation within two years, with 70% attributable to recurrent infections. Cite this article: Bone Joint J 2023;105-B(2):135–139

Aims. While interdisciplinary protocols and expedited surgical treatment improve the management of hip fractures in the elderly, the impact of such interventions on patients specifically undergoing arthroplasty for a femoral neck fracture is not clear. We sought to evaluate the efficacy of an interdisciplinary protocol for the management of patients with a femoral neck fracture who are treated with an arthroplasty. Methods. In 2017, our institution introduced a standardized interdisciplinary hip fracture protocol. We retrospectively reviewed adult patients who underwent hemiarthroplasty (HA) or total hip arthroplasty (THA) for femoral neck fracture between July 2012 and March 2020, and compared patient characteristics and outcomes between those treated before and after the introduction of the protocol. Results. A total of 157 patients were treated before the introduction of the protocol (35 (22.3%) with a THA), and 114 patients were treated after its introduction (37 (32.5%) with a THA). The demographic details and medical comorbidities were similar in the two groups. Patients treated after the introduction of the protocol had a significantly reduced median time between admission and surgery (22.8 hours (interquartile range (IQR) 18.8 to 27.7) compared with 24.8 hours (IQR 18.4 to 43.3) (p = 0.042), and a trend towards a reduced mean time to surgery (24.1 hours (SD 10.7) compared with 46.5 hours (SD 165.0); p = 0.150), indicating reduction in outliers. Patients treated after the introduction of the protocol had a significantly decreased rate of major complications (4.4% vs 17.2%; p = 0.005), decreased median hospital length of stay in hospital (4.0 days vs 4.8 days; p = 0.008), increased rate of discharge home (26.3% vs 14.7%; p = 0.030), and decreased one-year mortality (14.7% vs 26.3%; p = 0.049). The 90-day readmission rate (18.2% vs 21.7%; p = 0.528) and 30-day mortality (3.7% vs 5.1%; p = 0.767) did not significantly differ. Patients who underwent HA were significantly older than those who underwent THA (82.1 years (SD 10.4) vs 71.1 years (SD 9.5); p < 0.001), more medically complex (mean Charlson Comorbidity Index 6.4 (SD 2.6) vs 4.1 (SD 2.2); p < 0.001), and more likely to develop delirium (8.5% vs 0%; p = 0.024). Conclusion. The introduction of an interdisciplinary protocol for the management of elderly patients with a femoral neck fracture was associated with reduced time to surgery, length of stay, complications, and one-year mortality. Such interventions are critical in improving outcomes and reducing costs for an ageing population. Cite this article: Bone Joint J 2021;103-B(7 Supple B):3–8

In 1975, Sweden started registering primary knee replacement surgeries based on the personal identity number. Individual-based registrations of primary total hip replacements started in 1992 and for hemiarthroplasties the registration started in 2006. The completeness of these registrations is estimated at 98% during the last 10-year period. The long history and high completeness allow for accurate calculations of population-based prevalence of joint replacement and trends over time. We used all data on primary joint replacements available in the Swedish Arthroplasty Register. The prevalence was calculated using number of alive patients with 1) at least one joint replacement 2) at least one hip replacement 3) at least one knee replacement at the end of each year from 2010 – 2021. Publicly available population numbers were retrieved from Statistics Sweden. We calculated total prevalence and prevalence per age in years. By the end of 2021, 3.2% of the Swedish population had at least one hip or knee replacement. This was an increase from 2.5% in 2010. Among 80-year-old, the prevalence was 17.5% for any joint replacement. For both hip and knee replacement and all ages, the prevalence was higher for women. For knee replacement, the 2021 prevalence peaked at the age of 89 (9,4%) while the prevalence continuously increased with age for hip replacements. A considerable proportion of the Swedish elderly population is living with at least one hip or knee replacement. The prevalence has increased during the last 12-year period for both hips and knees. An increasing prevalence may also affect the incidence of fractures and infections. Knowledge about the prevalence is fundamental for planning future demand for primary and revision hip and knee replacement

Aims. Spinopelvic pathology increases the risk for instability following total hip arthroplasty (THA), yet few studies have evaluated how pathology varies with age or sex. The aims of this study were: 1) to report differences in spinopelvic parameters with advancing age and between the sexes; and 2) to determine variation in the prevalence of THA instability risk factors with advancing age. Methods. A multicentre database with preoperative imaging for 15,830 THA patients was reviewed. Spinopelvic parameter measurements were made by experienced engineers, including anterior pelvic plane tilt (APPT), spinopelvic tilt (SPT), sacral slope (SS), lumbar lordosis (LL), and pelvic incidence (PI). Lumbar flexion (LF), sagittal spinal deformity, and hip user index (HUI) were calculated using parameter measurements. Results. With advancing age, patients demonstrate increased posterior APPT, decreased standing LL, decreased LF, higher pelvic incidence minus lumbar lordosis (PI-LL) mismatch, higher prevalence of abnormal spinopelvic mobility, and higher HUI percentage. With each decade, APPT progressed posteriorly 2.1°, LF declined 6.0°, PI-LL mismatch increased 2.9°, and spinopelvic mobility increased 3.8°. Significant differences were found between the sexes for APPT, SPT, SS, LL, and LF, but were not felt to be clinically relevant. Conclusion. With advancing age, spinopelvic biomechanics demonstrate decreased spinal mobility and increased pelvic/hip mobility. Surgeons should consider the higher prevalence of instability risk factors in elderly patients and anticipate changes evolving in spinopelvic biomechanics for young patients. Cite this article: Bone Joint J 2024;106-B(8):792–801