Aims. Computer-assisted 3D preoperative planning software has the potential to improve postoperative stability in total hip arthroplasty (THA). Commonly, preoperative protocols simulate two functional positions (standing and relaxed sitting) but do not consider other common positions that may increase postoperative impingement and possible dislocation. This study investigates the feasibility of simulating commonly encountered positions, and positions with an increased risk of impingement, to lower postoperative impingement risk in a CT-based 3D model. Methods. A robotic arm-assisted arthroplasty planning platform was used to investigate 11 patient positions. Data from 43 primary THAs were used for simulation. Sacral slope was retrieved from patient preoperative imaging, while angles of hip flexion/extension, hip external/internal rotation, and hip abduction/adduction for tested positions were derived from literature or estimated with a biomechanical model. The hip was placed in the described positions, and if impingement was detected by the software, inspection of the impingement type was performed. Results. In flexion, an overall impingement rate of 2.3% was detected for flexed-seated, squatting, forward-bending, and criss-cross-sitting positions, and 4.7% for the ankle-over-knee position. In extension, most hips (60.5%) were found to impinge at or prior to 50° of external rotation (pivoting). Many of these impingement events were due to a prominent ischium. The mean maximum external rotation prior to impingement was 45.9° (15° to 80°) and 57.9° (20° to 90°) prior to prosthetic impingement. No impingement was found in standing, sitting, crossing ankles, seiza, and downward dog. Conclusion. This study demonstrated that positions of daily living tested in a CT-based 3D model show high rates of impingement. Simulating additional positions through 3D modelling is a low-cost method of potentially improving outcomes without compromising patient safety. By incorporating CT-based 3D modelling of positions of daily living into routine preoperative protocols for THA, there is the potential to lower the risk of postoperative impingement events. Cite this article: Bone Jt Open 2023;4(6):416–423

Aims. The aims of this systematic review were to assess the learning curve of semi-active robotic arm-assisted total hip arthroplasty (rTHA), and to compare the accuracy, patient-reported functional outcomes, complications, and survivorship between rTHA and manual total hip arthroplasty (mTHA). Methods. Searches of PubMed, Medline, and Google Scholar were performed in April 2020 in line with the Preferred Reporting Items for Systematic Review and Meta-Analysis statement. Search terms included “robotic”, “hip”, and “arthroplasty”. The criteria for inclusion were published clinical research articles reporting the learning curve for rTHA (robotic arm-assisted only) and those comparing the implantation accuracy, functional outcomes, survivorship, or complications with mTHA. Results. There were 501 articles initially identified from databases and references. Following full text screening, 17 articles that satisfied the inclusion criteria were included. Four studies reported the learning curve of rTHA, 13 studies reported on implant positioning, five on functional outcomes, ten on complications, and four on survivorship. The meta-analysis showed a significantly greater number of cases of acetabular component placement in the safe zone compared with the mTHA group (95% confidence interval (CI) 4.10 to 7.94; p < 0.001) and that rTHA resulted in a significantly better Harris Hip Score compared to mTHA in the short- to mid-term follow-up (95% CI 0.46 to 5.64; p = 0.020). However, there was no difference in infection rates, dislocation rates, overall complication rates, and survival rates at short-term follow-up. Conclusion. The learning curve of rTHA was between 12 and 35 cases, which was dependent on the assessment goal, such as operating time, accuracy, and team working. Robotic arm-assisted total hip arthroplasty was associated with improved accuracy of component positioning and functional outcome, however no difference in complication rates or survival were observed at short- to mid-term follow-up. Overall, there remains an absence of high-quality level I evidence and cost analysis comparing rTHA and mTHA. Cite this article: Bone Joint J 2021;103-B(6):1009–1020

Aims. This study aimed to assess the carbon footprint associated with total hip arthroplasty (THA) in a UK hospital setting, considering various components within the operating theatre. The primary objective was to identify actionable areas for reducing carbon emissions and promoting sustainable orthopaedic practices. Methods. Using a life-cycle assessment approach, we conducted a prospective study on ten cemented and ten hybrid THA cases, evaluating carbon emissions from anaesthetic room to recovery. Scope 1 and scope 2 emissions were considered, focusing on direct emissions and energy consumption. Data included detailed assessments of consumables, waste generation, and energy use during surgeries. Results. The carbon footprint of an uncemented THA was estimated at 100.02 kg CO2e, with a marginal increase to 104.89 kg CO2e for hybrid THA. Key contributors were consumables in the operating theatre (21%), waste generation (22%), and scope 2 emissions (38%). The study identified opportunities for reducing emissions, including instrument rationalization, transitioning to LED lighting, and improving waste-recycling practices. Conclusion. This study sheds light on the substantial carbon footprint associated with THA. Actionable strategies for reducing emissions were identified, emphasizing the need for sustainable practices in orthopaedic surgery. The findings prompt a critical discussion on the environmental impact of single-use versus reusable items in the operating theatre, challenging traditional norms to make more environmentally responsible choices. Cite this article: Bone Jt Open 2024;5(9):742–748

Aims. Young adults undergoing total hip arthroplasty (THA) largely have different indications for surgery, preoperative function, and postoperative goals compared to a standard patient group. The aim of our study was to describe young adult THA preoperative function and quality of life, and to assess postoperative satisfaction and compare this with functional outcome measures. Methods. A retrospective cohort analysis of young adults (aged < 50 years) undergoing THA between May 2018 and May 2023 in a single tertiary centre was undertaken. Median follow-up was 31 months (12 to 61). Oxford Hip Score (OHS) and focus group-designed questionnaires were distributed. Searches identified 244 cases in 225 patients. Those aged aged under 30 years represented 22.7% of the cohort. Developmental dysplasia of the hip (50; 45.5%) and Perthes’ disease (15; 13.6%) were the commonest indications for THA. Results. Preoperatively, of 110 patients, 19 (17.2%) were unable to work before THA, 57 (52%) required opioid analgesia, 51 (46.4%) were reliant upon walking aids, and 70 (63.6%) had sexual activity limited by their pathology. One patient required revision due to instability. Mean OHS was 39 (9 to 48). There was a significant difference between the OHS of cases where THA met expectation, compared with the OHS when it did not (satisfied: 86 (78.2%), OHS: 41.2 (36.1%) vs non-satisfied: 24 (21%), OHS: 31.6; p ≤ 0.001). Only one of the 83 patients (75.5%) who returned to premorbid levels of activity did so after 12 months. Conclusion. Satisfaction rates of THA in young adults is high, albeit lower than commonly quoted figures. Young adults awaiting THA have poor function with high requirements for mobility aids, analgesia, and difficulties in working and undertaking leisure activities. The OHS provided a useful insight into patient function and was predictive of satisfaction rates, although it did not address the specific demands of young adults undertaking THA. Function at one year postoperatively is a good indication of overall outcomes. Cite this article: Bone Jt Open 2024;5(4):304–311

Aims. Postoperative length of stay (LOS) and discharge dispositions following arthroplasty can be used as surrogate measurements for improvements in patients’ pathways and costs. With the increasing use of robotic technology in arthroplasty, it is important to assess its impact on LOS. The aim of this study was to identify factors associated with decreased LOS following robotic arm-assisted total hip arthroplasty (RO THA) compared with the conventional technique (CO THA). Methods. This large-scale, single-institution study included 1,607 patients of any age who underwent 1,732 primary THAs for any indication between May 2019 and January 2023. The data which were collected included the demographics of the patients, LOS, type of anaesthetic, the need for treatment in a post-anaesthesia care unit (PACU), readmission within 30 days, and discharge disposition. Univariate and multivariate logistic regression models were used to identify factors and the characteristics of patients which were associated with delayed discharge. Results. The multivariate model identified that age, female sex, admission into a PACU, American Society of Anesthesiologists grade > II, and CO THA were associated with a significantly higher risk of a LOS of > two days. The median LOS was 54 hours (interquartile range (IQR) 34 to 78) in the RO THA group compared with 60 hours (IQR 51 to 100) in the CO THA group (p < 0.001). The discharge dispositions were comparable between the two groups. A higher proportion of patients undergoing CO THA required PACU admission postoperatively, although without reaching statistical significance (7.2% vs 5.2%, p = 0.238). Conclusion. We found that among other baseline characteristics and comorbidities, RO THA was associated with a significantly shorter LOS, with no difference in discharge destination. With the increasing demand for THA, these findings suggest that robotic assistance in THA could reduce costs. However, randomized controlled trials are required to investigate the cost-effectiveness of this technology. Cite this article: Bone Joint J 2024;106-B(3 Supple A):24–30

Aims. The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy. Methods. We included patients who underwent THA using Wagner Cone due to proximal femur anatomical abnormalities between August 2014 and January 2019 at a single institution. We investigated implant survival time using the endpoint of dislocation and revision, and compared the prevalence of prosthetic impingements between the Wagner Cone, a tapered cone stem, and the Taperloc, a tapered wedge stem, through simulation. We also collected Oxford Hip Score (OHS), visual analogue scale (VAS) satisfaction, and VAS pain by postal survey in August 2023 and explored variables associated with those scores. Results. Of the 58 patients (62 hips), two (two hips) presented with dislocation or reoperation, and Kaplan-Meier analysis indicated a five-year survival rate of 96.7% (95% CI 92.4 to 100). Mean stem anteversion was 35.2° (SD 18.2°) for the Taperloc stem and 29.8° (SD 7.9°) for the Wagner Cone stem; mean reduction from Taperloc to Wagner Cone was 5.4° (SD 18.8°). Overall, 55 hips (52 patients) were simulated, and the prevalence of prosthetic impingement was lower for the Wagner Cone (5.5%, 3/55) compared with the Taperloc (20.0%, 11/55) stem, with an odds ratio of 0.20 (p = 0.038). Among the 33 respondents to the postal survey (36 hips), the mean scores were VAS pain 10.9, VAS satisfaction 86.9, and OHS 44.7. A multivariable analysis revealed that reduction of stem anteversion from Taperloc to Wagner Cone was more favourable for VAS pain (p = 0.029) and VAS satisfaction (p = 0.002). Conclusion. The mid-term survival rate for THA using the Wagner Cone stem was high, which may be supported by a reduction in prosthetic impingement. The reduction in excessive stem anteversion by using a tapered cone stem was associated with reduced pain and increased patient satisfaction. Cite this article: Bone Jt Open 2024;5(10):858–867

Aims. Obesity is associated with an increased risk of hip osteoarthritis, resulting in an increased number of total hip arthroplasties (THAs) performed annually. This study examines the peri- and postoperative outcomes of morbidly obese (MO) patients (BMI ≥ 40 kg/m. 2. ) compared to healthy weight (HW) patients (BMI 18.5 to < 25 kg/m. 2. ) who underwent a THA using the anterior-based muscle-sparing (ABMS) approach. Methods. This retrospective cohort study observes peri- and postoperative outcomes of MO and HW patients who underwent a primary, unilateral THA with the ABMS approach. Data from surgeries performed by three surgeons at a single institution was collected from January 2013 to August 2020 and analyzed using Microsoft Excel and Stata 17.0. Results. This study compares 341 MO to 1,140 HW patients. Anaesthesia, surgery duration, and length of hospital stay was significantly lower in HW patients compared to MO. There was no difference in incidence of pulmonary embolism, periprosthetic fracture, or dislocation between the two groups. The rate of infection in MO patients (1.47%) was significantly higher than HW patients (0.14%). Preoperative patient-reported outcome measures (PROMs) show a significantly higher pain level in MO patients and a significantly lower score in functional abilities. Overall, six-week and one-year postoperative data show higher levels of pain, lower levels of functional improvement, and lower satisfaction scores in the MO group. Conclusion. The comorbidities of obesity are well studied; however, the implications of THA using the ABMS approach have not been studied. Our peri- and postoperative results demonstrate significant improvements in PROMs in MO patients undergoing THA. However, the incidence of deep infection was significantly higher in this group compared with HW patients. Cite this article: Bone Jt Open 2023;4(5):299–305

Aims. The aim of this study was to evaluate the reliability and validity of a patient-specific algorithm which we developed for predicting changes in sagittal pelvic tilt after total hip arthroplasty (THA). Methods. This retrospective study included 143 patients who underwent 171 THAs between April 2019 and October 2020 and had full-body lateral radiographs preoperatively and at one year postoperatively. We measured the pelvic incidence (PI), the sagittal vertical axis (SVA), pelvic tilt, sacral slope (SS), lumbar lordosis (LL), and thoracic kyphosis to classify patients into types A, B1, B2, B3, and C. The change of pelvic tilt was predicted according to the normal range of SVA (0 mm to 50 mm) for types A, B1, B2, and B3, and based on the absolute value of one-third of the PI-LL mismatch for type C patients. The reliability of the classification of the patients and the prediction of the change of pelvic tilt were assessed using kappa values and intraclass correlation coefficients (ICCs), respectively. Validity was assessed using the overall mean error and mean absolute error (MAE) for the prediction of the change of pelvic tilt. Results. The kappa values were 0.927 (95% confidence interval (CI) 0.861 to 0.992) and 0.945 (95% CI 0.903 to 0.988) for the inter- and intraobserver reliabilities, respectively, and the ICCs ranged from 0.919 to 0.997. The overall mean error and MAE for the prediction of the change of pelvic tilt were -0.3° (SD 3.6°) and 2.8° (SD 2.4°), respectively. The overall absolute change of pelvic tilt was 5.0° (SD 4.1°). Pre- and postoperative values and changes in pelvic tilt, SVA, SS, and LL varied significantly among the five types of patient. Conclusion. We found that the proposed algorithm was reliable and valid for predicting the standing pelvic tilt after THA. Cite this article: Bone Joint J 2024;106-B(1):19–27

The orientation of the acetabular component can influence both the short- and long-term outcomes of total hip replacement (THR). We performed a prospective, randomised, controlled trial of two groups, comprising of 40 patients each, in order to compare freehand introduction of the component with introduction using the transverse acetabular ligament (TAL) as a reference for anteversion. Anteversion and inclination were measured on pelvic radiographs.

With respect to anteversion, in the freehand group 22.5% of the components were outside the safe zone versus 0% in the transverse acetabular ligament group (p = 0.002). The mean angle of anteversion in the freehand group was 21° (2° to 35°) which was significantly higher compared with 17° (2° to 25°) in the TAL group (p = 0.004). There was a significant difference comparing the variations of both groups (p = 0.008).

With respect to inclination, in the freehand group 37.5% of the components were outside the safe zone versus 20% in the TAL group (p = 0.14). There was no significant difference regarding the accuracy or variation of the angle of inclination when comparing the two groups.

The transverse acetabular ligament may be used to obtain the appropriate anteversion when introducing the acetabular component during THR, but not acetabular component inclination.

Cite this article: Bone Joint J 2014;96-B:312–18.

Revision of a cemented hemiarthroplasty of the hip may be a hazardous procedure with high rates of intra-operative complications. Removing well-fixed cement is time consuming and risks damaging already weak bone or perforating the femoral shaft. The cement-in-cement method avoids removal of intact cement and has shown good results when used for revision total hip arthroplasty (THA). The use of this technique for the revision of a hemiarthroplasty to THA has not been previously reported.

A total of 28 consecutive hemiarthroplasties (in 28 patients) were revised to a THA using an Exeter stem and the cement-in-cement technique. There were four men and 24 women; their mean age was 80 years (35 to 93). Clinical and radiographic data, as well as operative notes, were collected prospectively and no patient was lost to follow-up.

Four patients died within two years of surgery. The mean follow up of the remainder was 70 months (25 to 124). Intra-operatively there was one proximal perforation, one crack of the femoral calcar and one acetabular fracture. No femoral components have required subsequent revision for aseptic loosening or are radiologically loose.

Four patients with late complications (14%) have since undergone surgery (two for a peri-prosthetic fracture, and one each for deep infection and recurrent dislocation) resulting in an overall major rate of complication of 35.7%.

The cement-in-cement technique provides reliable femoral fixation in this elderly population and may reduce operating time and rates of complication.

Cite this article: Bone Joint J 2015;97-B:1623–7.

Aims. The aim of this study was to compare the early postoperative mortality and morbidity in older patients with a fracture of the femoral neck, between those who underwent total hip arthroplasty (THA) and those who underwent hemiarthroplasty. Methods. This nationwide, retrospective cohort study used data from the Japanese Diagnosis Procedure Combination database. We included older patients (aged ≥ 60 years) who underwent THA or hemiarthroplasty after a femoral neck fracture, between July 2010 and March 2022. A total of 165,123 patients were included. The THA group was younger (mean age 72.6 (SD 8.0) vs 80.7 years (SD 8.1)) and had fewer comorbidities than the hemiarthroplasty group. Patients with dementia or malignancy were excluded because they seldom undergo THA. The primary outcome measures were mortality and complications while in hospital, and secondary outcomes were readmission and reoperation within one and two years after discharge, and the costs of hospitalization. We conducted an instrumental variable analysis (IVA) using differential distance as a variable. Results. The IVA analysis showed that the THA group had a significantly higher rate of complications while in hospital (risk difference 6.3% (95% CI 2.0 to 10.6); p = 0.004) than the hemiarthroplasty group, but there was no significant difference in the rate of mortality while in hospital (risk difference 0.3% (95% CI -1.7 to 2.2); p = 0.774). There was no significant difference in the rate of readmission (within one year: risk difference 1.3% (95% CI -1.9 to 4.5); p = 0.443; within two years: risk difference 0.1% (95% CI -3.2 to 3.4); p = 0.950) and reoperation (within one year: risk difference 0.3% (95% CI -0.6 to 1.1); p = 0.557; within two years: risk difference 0.1% (95% CI -0.4 to 0.7); p = 0.632) after discharge. The costs of hospitalization were significantly higher in the THA group than in the hemiarthroplasty group (difference $2,634 (95% CI $2,496 to $2,772); p < 0.001). Conclusion. Among older patients undergoing surgery for a femoral neck fracture, the risk of early complications was higher after THA than after hemiarthroplasty. Our findings should aid in clinical decision-making in these patients. Cite this article: Bone Joint J 2024;106-B(9):986–993

Aims. For displaced femoral neck fractures (FNFs) in geriatric patients, there remains uncertainty regarding the effect of total hip arthroplasty (THA) compared with hemiarthroplasty (HA) in the guidelines. We aimed to compare 90-day surgical readmission, in-hospital complications, and charges between THA and HA in these patients. Methods. The Hospital Quality Monitoring System was queried from 1 January 2013 to 31 December 2019 for displaced FNFs in geriatric patients treated with THA or HA. After propensity score matching, which identified 33,849 paired patients, outcomes were compared between THA and HA using logistic and linear regression models. Results. The HA group had a lower incidence of 90-day surgical readmission than the THA group (odds ratio (OR) 0.75 (95% CI 0.68 to 0.83)). Meanwhile, the HA group had lower incidence of dislocation (OR 0.42 (95% CI 0.33 to 0.52)), aseptic loosening (OR 0.50 (95% CI 0.38 to 0.66)), and joint pain (OR 0.63 (95% CI 0.40 to 0.98)), but a higher incidence of periprosthetic fracture (OR 1.41 (95% CI 1.07 to 1.87)) for readmission, compared to the THA group. The incidence of in-hospital complications did not differ significantly between the two groups. Moreover, the HA group had lower mean charges than the THA group (47,578.29 Chinese Yuan (CNY) (SD 20,069.71) vs 57,641.00 CNY (SD 21,524.07)). Conclusion. When considering 90-day surgical readmission rate, in-hospital complications, and mortality, HA resulted in a significantly lower surgical readmission rate within 90 days compared to THA, despite the patients being older and having a higher Charlson Comorbidity Index. Cite this article: Bone Joint J 2024;106-B(12):1477–1484

Aims. A revision for periprosthetic joint infection (PJI) in total hip arthroplasty (THA) has a major effect on the patient’s quality of life, including walking capacity. The objective of this case control study was to investigate the histological and ultrastructural changes to the gluteus medius tendon (GMED) in patients revised due to a PJI, and to compare it with revision THAs without infection performed using the same lateral approach. Methods. A group of eight patients revised due to a PJI with a previous lateral approach was compared with a group of 21 revised THAs without infection, performed using the same approach. The primary variables of the study were the fibril diameter, as seen in transmission electron microscopy (TEM), and the total degeneration score (TDS), as seen under the light microscope. An analysis of bacteriology, classification of infection, and antibiotic treatment was also performed. Results. Biopsy samples from the GMED from infected patients revealed a larger fibril diameter than control patients, as seen in the TEM (p < 0.001). Uninfected patients were slightly older and had their revisions performed significantly later than the infected patients. Histologically, samples from infected patients revealed significantly more vascularity (p < 0.001), the presence of glycosaminoglycans (p < 0.001), and a higher TDS (p = 0.003) than the control patients. The majority of patients had staphylococcal infections of various species. Conclusion. More histological degeneration in the GMED was found in patients undergoing THA revision surgery due to PJI than in patients undergoing THA revision surgery due to other reasons. Cite this article: Bone Jt Open 2023;4(8):628–635

Aims. The prevalence of obesity is increasing substantially around the world. Elevated BMI increases the risk of complications following total hip arthroplasty (THA). We sought to evaluate trends in BMI and complication rates of obese patients undergoing primary THA over the last 30 years. Methods. Through our institutional total joint registry, we identified 15,455 primary THAs performed for osteoarthritis from 1990 to 2019. Patients were categorized according to the World Health Organization (WHO) obesity classification and groups were trended over time. Cox proportional hazards regression analysis controlling for confounders was used to investigate the association between year of surgery and two-year risk of any reoperation, any revision, dislocation, periprosthetic joint infection (PJI), venous thromboembolism (VTE), and periprosthetic fracture. Regression was stratified by three separate groups: non-obese; WHO Class I and Class II (BMI 30 to 39 kg/m. 2. ); and WHO Class III patients (BMI ≥ 40 kg/m. 2. ). Results. There was a significant increase in the proportion of all obesity classes from 1990 to 2019, and the BMI values within each WHO class significantly increased over time. Risk of any reoperation did not change over time among non-obese or WHO Class I/II patients, but increased for WHO Class III patients (hazard ratio (HR) 1.04; p = 0.044). Risk of dislocation decreased over time for non-obese (HR 0.96; p < 0.001) and WHO Class I/II (HR 0.96; p = 0.002) patients, but did not change over time for WHO Class III (HR 0.94; p = 0.073) patients. Risks of any revision and PJI did not change over time for any group. Conclusion. The proportion of patients undergoing THA who are obese has increased dramatically at our institution between 1990 and 2019. Despite BMI values increasing within all WHO classes over time, two-year complication risks have remained stable or decreased in WHO Class I/II patients. However, continued efforts will be required to mitigate risks in the heaviest WHO Class III patients. Cite this article: Bone Joint J 2024;106-B(11):1223–1230

Aims. Excessive posterior pelvic tilt (PT) may increase the risk of anterior instability after total hip arthroplasty (THA). The aim of this study was to investigate the changes in PT occurring from the preoperative supine to postoperative standing position following THA, and identify factors associated with significant changes in PT. Methods. Supine PT was measured on preoperative CT scans and standing PT was measured on preoperative and one-year postoperative standing lateral radiographs in 933 patients who underwent primary THA. Negative values indicate posterior PT. Patients with > 13° of posterior PT from preoperative supine to postoperative standing (ΔPT ≤ -13°) radiographs, which corresponds to approximately a 10° increase in functional anteversion of the acetabular component, were compared with patients with less change (ΔPT > -13°). Logistic regression analysis was used to assess preoperative demographic and spinopelvic parameters predictive of PT changes of ≤ -13°. The area under receiver operating characteristic curve (AUC) determined the diagnostic accuracy of the predictive factors. Results. PT changed from a mean of 3.8° (SD 6.0°)) preoperatively to -3.5° (SD 6.9°) postoperatively, a mean change of -7.4 (SD 4.5°; p < 0.001). A total of 95 patients (10.2%) had ≤ -13° change in PT from preoperative supine to postoperative standing. The strongest predictive preoperative factors of large changes in PT (≤ -13°) from preoperative supine to postoperative standing were a large posterior change in PT from supine to standing, increased supine PT, and decreased standing PT (p < 0.001). Flexed-seated PT (p = 0.006) and female sex (p = 0.045) were weaker significant predictive factors. When including all predictive factors, the accuracy of the AUC prediction was 84.9%, with 83.5% sensitivity and 71.2% specificity. Conclusion. A total of 10% of patients had > 13° of posterior PT postoperatively compared with their supine pelvic position, resulting in an increased functional anteversion of > 10°. The strongest predictive factors of changes in postoperative PT were the preoperative supine-to-standing differences, the anterior supine PT, and the posterior standing PT. Surgeons who introduce the acetabular component with the patient supine using an anterior approach should be aware of the potentially large increase in functional anteversion occurring in these patients. Cite this article: Bone Joint J 2024;106-B(3 Supple A):74–80

Aims. Adult patients with history of childhood infection pose a surgical challenge for total hip arthroplasty (THA) due to distorted bony anatomy, soft-tissue contractures, risk of reinfection, and relatively younger age. Therefore, the purpose of the present study was to determine clinical outcome, reinfection rate, and complications in patients with septic sequelae after THA. Methods. A retrospective analysis was conducted of 91 cementless THAs (57 male and 34 female) performed between 2008 and 2017 in patients who had history of hip infection during childhood. Clinical outcome was measured using Harris Hip Score (HHS) and Modified Merle d’Aubigne and Postel (MAP) score, and quality of life (QOL) using 12-Item Short Form Health Survey Questionnaire (SF-12) components: Physical Component Score (PCS) and Mental Component Score (MCS); limb length discrepancy (LLD) and radiological assessment of the prosthesis was performed at the latest follow-up. Reinfection and revision surgery after THA for any reason was documented. Results. There was significant improvement in HHS, Modified Merle d’Aubigne Postel hip score, and QOL index SF 12-PCS and MCS (p < 0.001) and there was no case of reinfection reported during the follow-up. The minimum follow-up for the study was three years with a mean of 6.5 (SD 2.3; 3 to 12). LLD decreased from a mean of 3.3 cm (SD 1) to 0.9 cm (SD 0.8) during follow-up. One patient required revision surgery for femoral component loosening. Kaplan-Meier survival analysis estimated revision-free survivorship of 100% at the end of five years and 96.9% (95% confidence interval 79.8 to 99.6) at the end of ten years. Conclusion. We found that cementless THA results in good to excellent functional outcomes in patients with a prior history of childhood infection. There is an exceedingly low rate of risk of reinfection in these patients, even though complications are not uncommon. Cite this article: Bone Jt Open 2022;3(4):314–320

Aims. Osteoporosis is common in total hip arthroplasty (THA) patients. It plays a substantial factor in the surgery’s outcome, and previous studies have revealed that pharmacological treatment for osteoporosis influences implant survival rate. The purpose of this study was to examine the prevalence of and treatment rates for osteoporosis prior to THA, and to explore differences in osteoporosis-related biomarkers between patients treated and untreated for osteoporosis. Methods. This single-centre retrospective study included 398 hip joints of patients who underwent THA. Using medical records, we examined preoperative bone mineral density measures of the hip and lumbar spine using dual energy X-ray absorptiometry (DXA) scans and the medications used to treat osteoporosis at the time of admission. We also assessed the following osteoporosis-related biomarkers: tartrate-resistant acid phosphatase 5b (TRACP-5b); total procollagen type 1 amino-terminal propeptide (total P1NP); intact parathyroid hormone; and homocysteine. Results. The prevalence of DXA-proven hip osteoporosis (T-score ≤ -2.5) among THA patients was 8.8% (35 of 398). The spinal osteoporosis prevalence rate was 4.5% (18 of 398), and 244 patients (61.3%; 244 of 398) had osteopenia (-2.5 < T-score ≤ -1) or osteoporosis of either the hip or spine. The rate of pharmacological osteoporosis treatment was 22.1% (88 of 398). TRACP-5b was significantly lower in the osteoporosis-treated group than in the untreated group (p < 0.001). Conclusion. Osteoporosis is common in patients undergoing THA, but the diagnosis and treatment for osteoporosis were insufficient. The lower TRACP-5b levels in the osteoporosis-treated group — that is, osteoclast suppression — may contribute to the reduction of the postoperative revision rate after THA. Cite this article: Bone Joint Res 2022;11(12):873–880

Aims. Mechanical impingement of the iliopsoas (IP) tendon accounts for 2% to 6% of persistent postoperative pain after total hip arthroplasty (THA). The most common initiator is anterior acetabular component protrusion, where the anterior margin is not covered by anterior acetabular wall. A CT scan can be used to identify and measure this overhang; however, no threshold exists for determining symptomatic anterior IP impingement due to overhang. A case-control study was conducted in which CT scan measurements were used to define a threshold that differentiates patients with IP impingement from asymptomatic patients after THA. Methods. We analyzed the CT scans of 622 patients (758 THAs) between May 2011 and May 2020. From this population, we identified 136 patients with symptoms suggestive of IP impingement. Among them, six were subsequently excluded: three because the diagnosis was refuted intraoperatively, and three because they had another obvious cause of impingement, leaving 130 hips (130 patients) in the study (impingement) group. They were matched to a control group of 138 asymptomatic hips (138 patients) after THA. The anterior acetabular component overhang was measured on an axial CT slice based on anatomical landmarks (orthogonal to the pelvic axis). Results. The impingement group had a median overhang of 8 mm (interquartile range (IQR) 5 to 11) versus 0 mm (IQR 0 to 4) for the control group (p < 0.001). Using receiver operating characteristic curves, an overhang threshold of 4 mm was best correlated with a diagnosis of impingement (sensitivity 79%, specificity 85%; positive predictive value 75%, negative predictive value 85%). Conclusion. Pain after THA related to IP impingement can be reasonably linked to acetabular overhang if it exceeds 4 mm on a CT scan. Below this threshold, it seems logical to look for another cause of IP irritation or another reason for the pain after THA before concluding that impingement is present. Cite this article: Bone Joint J 2024;106-B(3 Supple A):97–103

Aims. Overall sagittal flexion is restricted in patients who have undergone both lumbar fusion and total hip arthroplasty (THA). However, it is not evident to what extent this movement is restricted in these patients and how this influences quality of life (QoL). The purpose of this study was to determine the extent to which hip-lumbar mobility is decreased in these patients, and how this affects their QoL score. Methods. Patients who underwent primary THA at our hospital between January 2010 and March 2021 were considered (n = 976). Among them, 44 patients who underwent lumbar fusion were included as cases, and 44 THA patients without lumbar disease matched by age, sex, and BMI as Control T. Among those who underwent lumbar fusion, 44 patients without hip abnormalities matched by age, sex, and BMI to the cases were considered as Control F. Outcome and spinopelvic parameters were measured radiologically in extension and flexed-seated positions. Hip, lumbar, and hip-lumbar mobility were calculated as parameter changes between positions. Results. There were 20 male and 112 female patients in the case and control groups, with a mean age of 77 years (5 to 94) and a mean BMI of 24 kg/m. 2. (15 to 34). QoL score and hip-lumbar mobility were reduced in cases compared to Control T and F, and were further reduced as the number of fused levels increased. Hip-lumbar mobility was associated with reduction in activity-related QoL, mostly for those activities requiring sagittal flexion. Conclusion. This study confirmed that hip-lumbar mobility is a factor that influences activity, most of all those requiring overall sagittal flexion. Clinicians should focus on hip-lumbar mobility and counteract disability by suggesting appropriate assistive devices. Cite this article: Bone Joint J 2025;107-B(1):34–41

Aims. Osteoporosis can determine surgical strategy for total hip arthroplasty (THA), and perioperative fracture risk. The aims of this study were to use hip CT to measure femoral bone mineral density (BMD) using CT X-ray absorptiometry (CTXA), determine if systematic evaluation of preoperative femoral BMD with CTXA would improve identification of osteopenia and osteoporosis compared with available preoperative dual-energy X-ray absorptiometry (DXA) analysis, and determine if improved recognition of low BMD would affect the use of cemented stem fixation. Methods. Retrospective chart review of a single-surgeon database identified 78 patients with CTXA performed prior to robotic-assisted THA (raTHA) (Group 1). Group 1 was age- and sex-matched to 78 raTHAs that had a preoperative hip CT but did not have CTXA analysis (Group 2). Clinical demographics, femoral fixation method, CTXA, and DXA data were recorded. Demographic data were similar for both groups. Results. Preoperative femoral BMD was available for 100% of Group 1 patients (CTXA) and 43.6% of Group 2 patients (DXA). CTXA analysis for all Group 1 patients preoperatively identified 13 osteopenic and eight osteoporotic patients for whom there were no available preoperative DXA data. Cemented stem fixation was used with higher frequency in Group 1 versus Group 2 (28.2% vs 14.3%, respectively; p = 0.030), and in all cases where osteoporosis was diagnosed, irrespective of technique (DXA or CTXA). Conclusion. Preoperative hip CT scans which are routinely obtained prior to raTHA can determine bone health, and thus guide femoral fixation strategy. Systematic preoperative evaluation with CTXA resulted in increased recognition of osteopenia and osteoporosis, and contributed to increased use of cemented femoral fixation compared with routine clinical care; in this small study, however, it did not impact short-term periprosthetic fracture risk. Cite this article: Bone Joint J 2023;105-B(3):254–260