Aims

This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).

Aims. The optimum clearance between the bearing surfaces of hip arthroplasties is unknown. Theoretically, to minimize wear, it is understood that clearances must be low enough to maintain optimal contact pressure and fluid film lubrication, while being large enough to allow lubricant recovery and reduce contact patch size. This study aimed to identify the relationship between diametrical clearance and volumetric wear, through the analysis of retrieved components. Methods. A total of 81 metal-on-metal Pinnacle hips paired with 12/14 stems were included in this study. Geometrical analysis was performed on each component, using coordinate and roundness measuring machines. The relationship between their as-manufactured diametrical clearance and volumetric wear was investigated. The Mann-Whitney U test and unpaired t-test were used, in addition to calculating the non-parametric Spearman's correlation coefficient, to statistically evaluate the acquired data. Results. The hips in this study were found to have had a median unworn diametrical clearance of 90.31 μm (interquartile range (IQR) 77.59 to 97.40); 32% (n = 26) were found to have been below the manufacturing tolerance. There was no correlation found between clearance and bearing (r. s. = -0.0004, p = 0.997) or taper (r. s. = 0.0048, p = 0.966) wear rates. The wear performance of hips manufactured within and below these specifications was not significantly different (bearing: p = 0.395; taper: p = 0.653). Pinnacles manufactured from 2007 onwards had a greater prevalence of bearing clearance below tolerance (p = 0.004). Conclusion. The diametrical clearance of Pinnacle hips did not influence their wear performance, even when below the manufacturing tolerance. The optimum clearance for minimizing hip implant wear remains unclear. Cite this article: Bone Joint Res 2020;9(8):515–523

Aims. Although there is increasing legalization of the use of cannabis in the USA, few well-powered studies have evaluated the association between cannabis use disorder and outcomes following primary total hip arthroplasty (THA). Thus, the aim of this study was to determine whether patients who use cannabis and undergo primary THA have higher rates of in-hospital length of stay (LOS), medical complications, implant-related complications, and costs. Methods. Using an administrative database, patients with cannabis use disorder undergoing primary THA were matched to a control group in a 1:5 ratio by age, sex, and various medical comorbidities. This yielded 23,030 patients (3,842 in the study group matched with 19,188 in the control group). The variables which were studied included LOS, 90-day medical complications, two-year implant-related complications, and 90-day costs of care. Mann-Whitney U tests were used to compare LOS and costs. Multivariate logistic regression analyses were used to calculate the odds ratios (ORs) of developing complications. Results. We found that patients in the study group had a significantly longer mean LOS compared with the controls (four days vs three days; p < 0.0001).The study group also had a significantly higher incidence and odds of developing medical (23.0 vs 9.8%, OR 1.6; p < 0.0001) and implant-related complications (16 vs 7.4%, OR 1.6; p < 0.0001) and incurred significantly higher mean 90-day costs ($16,938.00 vs $16,023.00; p < 0.0001). Conclusion. With the increasing rates of cannabis use, these findings allow orthopaedic surgeons and other healthcare professionals to counsel patients with cannabis use disorder about the possible outcomes following their THA, with increased hospital stays, complications, and costs. Cite this article: Bone Joint J 2021;103-B(7 Supple B):111–115

Aims. Two-stage exchange revision total hip arthroplasty (THA) performed in case of periprosthetic joint infection (PJI) has been considered for many years as being the gold standard for the treatment of chronic infection. However, over the past decade, there have been concerns about its safety and its effectiveness. The purposes of our study were to investigate our practice, collecting the overall spacer complications, and then to analyze their risk factors. Methods. We retrospectively included 125 patients with chronic hip PJI who underwent a staged THA revision performed between January 2013 and December 2019. All spacer complications were systematically collected, and risk factors were analyzed. Statistical evaluations were performed using the Student's t-test, Mann-Whitney U test, and Fisher's exact test. Results. Our staged exchange practice shows poor results, which means a 42% mechanical spacer failure rate, and a 20% recurrent infection rate over the two years average follow-up period. Moreover, we found a high rate of spacer dislocation (23%) and a low rate of spacer fracture (8%) compared to the previous literature. Our findings stress that the majority of spacer complications and failures is reflecting a population with high comorbid burden, highlighted by the American Society of Anesthesiology grade, Charlson Comorbidity Index, and Lee score associations, as well as the cardiac, pulmonary, kidney, or hepatic chronic conditions. Conclusion. Our experience of a two-stage hip exchange revision noted important complication rates associated with high failure rates of polymethylmethacrylate spacers. These findings must be interpreted in the light of the patient’s comorbidity profiles, as the elective population for staged exchange has an increasing comorbid burden leading to poor results. In order to provide better results for this specific population, our conclusion suggests that comparative strategy studies are required to improve our therapeutic indication. Cite this article: Bone Jt Open 2022;3(6):485–494

There is a strong association between the presence of a calcar collar on a cementless stem and a reduced risk of revision surgery for periprosthetic fracture of the femur (PFF). A medial calcar collar may act to reduce relative movement between the implant and femur during PFF, through calcar-collar contact (CCC). The aims were:. Estimate the effect of CCC on periprosthetic fracture mechanics. Estimate the effect of initial calcar-collar separation on the likelihood of CCC. Three groups of six composite femurs were implanted with a fully coated collared cementless femoral stem. Neck resection differed between groups (group 1 = no additional resection, group 2 = 3mm additional resection, group 3 = 6mm additional resection). PFF were simulated using a previously published technique. Fracture torque and rotational displacement were measured and torsional stiffness and rotational work prior to fracture were estimated. Results between trials where CCC did and did not occur where compared using Mann-Whitney U tests. Logistic regression estimated the odds (OR) of failing with 95% confidence interval (CI) to achieve CCC for a given initial separation. Where CCC occurred fracture torque was greater (47.33 [41.03 to 50.45] Nm versus 38.26 [33.70 to 43.60] Nm, p= 0.05) and torsional stiffness was greater (151.38 [123.04 to 160.42] rad.Nm. −1. versus 96.86 [84.65 to 112.98] rad.Nm. −1. , p <0.01). CCC was occurred in all cases in group one, 50% in group two and 0% in group three. OR of failure to obtain CCC increased 3.8 fold (95% CI 1.6 to 30.2, p <0.05) for each millimetre of separation. Resistance to fracture and construct stiffness increased when a the collar made contact with the calcar prior to fracture and the chances of contact decrease with increasing initial separation at the time of implantation. Surgeons should aim to achieve a calcar-collar distance of less than 1mm following implantation to ensure CCC and to reduce the risk of fracture

Introduction. Interferon (IFN) based treatments for chronic hepatitis C (HCV) have been the standard of care until 2014 when direct antiviral agents (DAA) were introduced. Patients with HCV have had extremely high complication rates after total hip arthroplasty (THA). It is unknown whether HCV is a modifiable risk factor for these complications prior to THA. The purpose of this study was 1) to compare perioperative complication rates between untreated and treated HCV in THA and 2) to compare these rates between patients treated with two different therapies (IFN vs. DAA). Methods. A multicenter retrospective database query was used to identify patients diagnosed with chronic hepatitis C virus who underwent total hip arthroplasty from 2006–2016. All patients (n=105) identified were included and were divided into two groups: untreated HCV (n=63) and treated (n=42); the treated group were further subdivided into those receiving IFN based therapies (n=16) or DAA therapies (n=26). Comparisons between the treated and untreated groups were made with respect to demographic data, comorbidities, preoperative viral load, MELD score, and all surgical (≤1 yr) and medical (≤90d) complications; a sub-group analysis of the treated patients was also performed. Separate independent t-tests were conducted for dependent variables that were normally distributed, and Mann-Whitney U tests were conducted for variables which were not normally distributed. Categorical variables were compared through the chi-square test of independence. The level of statistical significance was set at p<0.05. Results. Of the 105 patients, there was a greater number of HIV infected patients in the untreated group and a higher number of smokers in the treated group. Surgical complication rates were higher in the untreated group (25.4% vs. 4.8%; p<0.05) with a PJI rate of 14.3% in the untreated group. There were no differences in medical complications. A sub-group analysis of the different treatments for HCV did not reveal any differences in post-surgical complications. Discussion and Conclusion. Untreated HCV is traditionally associated with an extremely high rate of postoperative complications following THA. Treatment for HCV prior to THA appears to be associated fewer postoperative complications, primarily PJI. While further investigation is warranted, strong consideration should be given to treating patients for HCV prior to elective THA

The statements contained in this document are solely those of the authors and do not necessarily reflect the views or policies of CMS. The authors assume responsibility for the accuracy and completeness of the information contained in this document. Background. The Bundled Payments for Care Improvement (BPCI) initiative was introduced to reduce healthcare costs while maintaining quality. We examined data from a healthcare system comprised of five hospitals that elected to participate in the BPCI Major Joint Replacement of the Lower Extremity Model 2 initiative beginning July 1, 2015. We compared one hospital that did 439 BPCI hip cases to the four other hospitals that did 459 cases. Stratifying the data by hospital volume, we sought to determine if costs decreased during the BPCI period, how the savings were achieved, and if savings resulted in financial rewards for participation. Methods. The Medicare data included the target cost for each episode (based on historical data from 2009–2012 for each hospital that was adjusted quarterly) and actual Part A and Part B spending for 90 days. Using 1,574 primary hip replacements, we analyzed the costs associated with the anchor hospitalization, inpatient rehabilitation, skilled nursing facilities, home health, outpatient physical therapy and readmission to compare the 898 hips done during the 16-month BPCI initiative period with the 676 hips done during the 1-year period preceding BPCI participation. Owing to the nonparametric distribution of the cost data, a Mann-Whitney U test was used to compare the higher volume hospital with the four lower volume hospitals. Results. Compared to the preceding year, the mean episode of care cost during BPCI participation decreased by 14.1% (from $21,823 to $18,755, p=0.02) at the higher volume hospital and by 13.1% (from $32,138 to $27,940, p=0.02) at the lower volume hospitals. During the BPCI period, the mean Medicare target cost was $18,490 at the higher volume hospital and $25,021 at the lower volume hospitals (p<0.001). At the higher volume hospital, the major components of the savings included $526,028 from reduced readmission rates (11.5% versus 3.0%, p<0.001), $393,757 primarily due to reduced length of stay at skilled nursing facilities (mean 33 days versus 26 days, p=0.07), and $205,459 associated with a decreased percentage of patients using inpatient rehabilitation (6.6% versus 3.2%, p=0.03). At the lower volume hospitals, the major components of the savings included $1,002,447 associated with a reduction in the length of stay at skilled nursing facilities (mean 37 days versus 27 days, p<0.001), $487,356 associated with a decrease in the percentage of patients using inpatient rehab (11.6% versus 6.5%, p=0.01), and $355,695 associated with reduced readmission costs. Despite the savings, the mean reconciliation penalty was $184 per case at the higher volume hospital and $2,309 per case at the lower volume hospitals. Stratified by the type of hip replacement, reconciliation for elective primaries resulted in a mean reward of $848 per case for the 409 hips performed at the higher volume hospital and $2,497 per case for the 266 hips done at the lower volume hospitals. For hip fracture cases, reconciliation resulted in a mean penalty of $14,248 per case among the 30 hips done at the higher volume hospital and $8,932 per case for the 193 hips done at the lower volume hospitals. Conclusions. Based on the reduction in costs and decreased readmission rates, the BPCI initiative is achieving its objectives. Although the higher and lower volume hospitals achieved savings during BPCI participation, the target costs were lower than the actual costs resulting in a reconciliation penalty that was driven by the cost of hip fractures. The reconciliation rewards associated with elective primary THAs compared to the substantial penalties associated with hip fractures support the premise that these groups should have different targets costs

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.

Aims

Lateral femoral cutaneous nerve (LFCN) injury is a potential complication after the direct anterior approach for total hip arthroplasty (DAA-THA). The aim of this study was to determine how the location of the fasciotomy in DAA-THA affects LFCN injury.

Aims

In metal-on-metal (MoM) hip arthroplasties and resurfacings, mechanically induced corrosion can lead to elevated serum metal ions, a local inflammatory response, and formation of pseudotumours, ultimately requiring revision. The size and diametral clearance of anatomical (ADM) and modular (MDM) dual-mobility polyethylene bearings match those of Birmingham hip MoM components. If the acetabular component is satisfactorily positioned, well integrated into the bone, and has no surface damage, this presents the opportunity for revision with exchange of the metal head for ADM/MDM polyethylene bearings without removal of the acetabular component.

Aims

Excellent outcomes have been reported following CT-based robotic arm-assisted total hip arthroplasty (rTHA) compared with manual THA; however, its superiority over CT-based navigation THA (nTHA) remains unclear. This study aimed to determine whether a CT-based robotic arm-assisted system helps surgeons perform accurate cup placement, minimizes leg length, and offsets discrepancies more than a CT-based navigation system.

Aims

To evaluate the concurrent use of vancomycin and ε-aminocaproic acid (EACA) in primary total hip arthroplasty (THA).

Aims

Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA.

Aims

Periacetabular osteotomy (PAO) is well established for acetabular reorientation and has shown successful improvement in patient-reported outcome measures (PROMs). Nevertheless, studies focusing on postoperative outcomes related to patient individual factors are still underrepresented. Therefore, this study aimed to analyze the functional outcome and activity level in relation to patient sex with a minimum follow-up of two years after PAO for mild to severe hip dysplasia.

Aims

This study aimed to investigate whether the use of CT-based navigation enhances: 1) the accuracy of cup placement; and 2) the achievement rate of required range of motion (ROM). Additionally, we investigated the impact of using a large femoral head and dual-mobility liner on the achievement rates.

Aims

The aim of this study was to compare the pattern of initial fixation and changes in periprosthetic bone mineral density (BMD) between patients who underwent total hip arthroplasty (THA) using a traditional fully hydroxyapatite (HA)-coated stem (T-HA group) and those with a newly introduced fully HA-coated stem (N-HA group).

Aims

The primary aim of this study was to compare surgical methods (sliding hip screw (SHS) vs intramedullary nailing (IMN)) for trochanteric hip fracture in relation to death within 120 days after surgery and return to independent living. The secondary aim was to assess whether the associations between surgical method and death or ability to return to independent living varied depending on fracture subtype or other patient characteristics.

Aims

The aim of this study was to compare open reduction and internal fixation (ORIF) with revision surgery for the surgical management of Unified Classification System (UCS) type B periprosthetic femoral fractures around cemented polished taper-slip femoral components following primary total hip arthroplasty (THA).

Aims

This study aims to assess the relationship between history of pseudotumour formation secondary to metal-on-metal (MoM) implants and periprosthetic joint infection (PJI) rate, as well as establish ESR and CRP thresholds that are suggestive of infection in these patients. We hypothesized that patients with a pseudotumour were at increased risk of infection.

Aims

Periprosthetic fracture and implant loosening are two of the major reasons for revision surgery of cementless implants. Optimal implant fixation with minimal bone damage is challenging in this procedure. This pilot study investigates whether vibratory implant insertion is gentler compared to consecutive single blows for acetabular component implantation in a surrogate polyurethane (PU) model.