Assessing brain integrity in patients with long-term and well-functioning metal-based hip implants

Production of metal debris from implant wear and corrosion processes is now a well understood occurrence following hip arthroplasty. Evidence has shown that metal ions can enter the bloodstream and travel to distant organs including the brain, and in extreme cases, can induce sensorial and neurological diseases. Our objective was tosimultaneously analyze brain anatomy and physiology in patients with long-term and well-functioning implants. Included were subjects who had received total hip or hip resurfacing arthroplastywith an implantation time of a minimum of 7 years (n = 28) and age- and sex-matched controls (n = 32). Blood samples were obtained to measure ion concentrations of cobalt and chromium, and the Montreal Cognitive Assessment was performed. 3T MRI brain scans were completed with an MPRAGE sequence for ROI segmentation and multiecho gradient echo sequences to generate QSM and R2* maps. Mean QSM and R2* values were recorded for five deep brain and four middle and cortical brain structures on both hemispheres: pallidum, putamen, caudate, amygdala, hippocampus, anterior cingulate, inferior temporal, and cerebellum. No differences in QSM or R2* or cognition scores were found between both groups (p > 0.6654). No correlation was found between susceptibility and blood ion levels for cobalt or chromium in any region of the brain. No correlation was found between blood ion levels and cognition scores. Clinical significance: Results suggest that metal ions released by long-term and well-functioning implants do not affect brain integrity.

Cup safe zone and optimal stem anteversion in total hip arthroplasty for patients with highly required range of motion

To avoid dislocation after total hip arthroplasty, it is desirable to avoid implant impingement during activities of daily living. Numerous simulation studies have been performed at 30° of internal rotation (IR) with 90° of flexion. However, these studies may not reflect the impingement that occurs during activities such as floor sitting, which require a larger IR during flexion. The purpose of this study was to assess the impact of varying IR angles during flexion on the impingement-free safe zone and optimal stem anteversion. In this study, implant impingement simulation was evaluated in computer simulation. The prosthesis used a flat liner, and a 32- or 40-mm femoral head and stem. Three patterns of required IR angle (30° IR/40° IR/50° IR with 90° flexion) combined with 13 directions of the required range of motion were simulated. The optimal stem anteversion to maximize the safe zone was analyzed. Increasing the required IR at 90° flexion decreased the safe zone, particularly with small stem anteversion angles. With a 32-mm head, the desirable stem anteversion at 40° of cup inclination was 15°/25°/35° in required 30° IR/40° IR/50° IR with 90° flexion, respectively. The safe zone area of the 32-mm head was smaller than that of the 40-mm head. For patients who require a larger IR with 90° flexion, the stem and cup target anteversion should be adjusted according to the implant design, head diameter, and patient's required IR at flexion in their lifestyle.

How to Raise the Bar in the Capture of Patient-Reported Outcome Measures in Total Joint Arthroplasty: Results from Active and Passive Follow-up Measures

BACKGROUND

With the upcoming U.S. Centers for Medicare & Medicaid Services 2027 policy for mandatory reporting of patient-reported outcome measures (PROMs) for total hip or knee arthroplasty (THA or TKA), it is important to evaluate the resources required to achieve adequate PROM collection and reporting at a clinically relevant rate of follow-up. This study aimed to (1) determine follow-up rates for 1-year PROMs when the follow-up was conducted with active methods (attempted contact by staff) and passive (automated) methods, and (2) evaluate factors associated with higher odds of requiring active follow-up or being lost to follow-up following THA or TKA.

METHODS

A prospective cohort of patients undergoing primary elective THA (n = 7,436) or TKA (n = 10,119) between January 2016 and December 2020 at a single institution were included. The primary outcome was the response rate achieved with active and passive follow-up methods at our institution. Patient characteristics, health-care utilization parameters, PROM values, and patient satisfaction were compared between follow-up methods.

RESULTS

Passive and active measures were successful for 38% (2,859) and 40% (3,004) of the THA cohort, respectively, while 21% (1,573) were lost to follow-up. Similarly, passive and active measures were successful for 40% (4,001) and 41% (4,161) of the TKA cohort, respectively, while 20% (2,037) were lost to follow-up. Younger age, male sex, Black or another non-White race, fewer years of education, smoking, Medicare or Medicaid insurance, and specific baseline PROM phenotypes (i.e., with scores in the lower half for pain, function, and/or mental health) were associated with loss to follow-up. Older age, male sex, Black race, and a residence with a higher Area Deprivation Index were associated with requiring active follow-up.

CONCLUSIONS

One of 5 patients were lost to follow-up despite active and passive measures following THA or TKA. These patients were more likely to be younger, be male, be of Black or another non-White race, have fewer years of education, be a smoker, have Medicaid insurance, and have specific baseline PROM phenotypes. Innovative strategies aimed at targeting individuals with these baseline characteristics may help raise the bar and increase follow-up while mitigating costs after total joint arthroplasty.

LEVEL OF EVIDENCE

Prognostic Level II . See Instructions for Authors for a complete description of levels of evidence.

Outcomes After Pseudomonas Prosthetic Joint Infections

BACKGROUND

Pseudomonas species are a less common but devastating pathogen family in prosthetic joint infections (PJIs). Despite advancements in management, Pseudomonas PJIs remain particularly difficult to treat because of limited antibiotic options and robust biofilm formation. This study aimed to evaluate Pseudomonas PJI outcomes at a single institution and review outcomes reported in the current literature.

METHODS

All hip or knee PJIs at a single institution with positive Pseudomonas culture were evaluated. Forty-two patients (24 hips, 18 knees) meeting inclusion criteria were identified. The primary outcome of interest was infection clearance at 1 year after surgical treatment, defined as reassuring aspirate without ongoing antibiotic treatment. Monomicrobial and polymicrobial infections were analyzed separately. A focused literature review of infection clearance after Pseudomonas PJIs was performed.

RESULTS

One-year infection clearance was 58% (n = 11/19) for monomicrobial PJIs and 35% (n = 8/23) for polymicrobial PJIs. Among monomicrobial infections, the treatment success was 63% for patients treated with DAIR and 55% for patients treated with two-stage exchange. Monotherapy with an oral or intravenous antipseudomonal agent (minimum 6 weeks) displayed the lowest 1-year clearance of 50% (n = 6/12). Resistance to antipseudomonal agents was present in 16% (n = 3/19), and two of eight patients with monomicrobial and polymicrobial PJIs developed resistance to antipseudomonal therapy in a subsequent Pseudomonas PJI. Polymicrobial infections (55%) were more common with a mortality rate of 44% (n = 10/23) at a median follow-up of 3.6 years.

CONCLUSION

Pseudomonas infections often present as polymicrobial PJIs but are difficult to eradicate in either polymicrobial or monomicrobial setting. A review of the current literature on Pseudomonas PJI reveals favorable infection clearance rates (63 to 80%) after DAIR while infection clearance rates (33 to 83%) vary widely after two-stage revision.

Early Postoperative Change in Hip Rotation Angle and Factors Contributing to It for Patients Undergoing Total Hip Arthroplasty

OBJECTIVE

A possible impairment in hip proprioception after total hip arthroplasty (THA) has been an issue of concern. The aims of this study were to investigate the extent of early postoperative change in standing hip rotation angle (HRAng) in patients with osteoarthritis (OA) undergoing THA and to consider a possible mechanism behind this.

MATERIALS AND METHODS

A total of 82 hips (82 patients; 63 women and 19 men) undergoing unilateral primary THA with total capsulectomy were included. We characterized the standing HRAng and internal/external range of motion (ROM) in the prone position before THA and 2 weeks after THA. Acetabular/cup and femoral/stem anteversion, combined anteversion (CA), and leg length discrepancy were also characterized. Correlations were examined postoperatively between the HRAng and the other analyzed variables.

RESULTS

The median standing HRAng showed a significant internal shift from external to more medial position (6.3° to 1.7°) 2 weeks after THA (P<.0001). The postoperative change in standing HRAng was significantly negatively correlated with the difference between the postoperative femoral anteversion and the stem anteversion (rs=-0.429, P<.0001) and with the pre- to postoperative change in CA (rs=-0.3012, P=.0063).

CONCLUSION

This study demonstrated that the extent of the rotational shift of the distal femur toward medial direction was significantly associated with increasing stem anteversion and CA. This phenomenon can be interpreted as a compensatory mechanism for maintaining the relative positional relationship between the pelvis and the proximal femur using proprioception. Therefore, we conclude that the extracapsular/extra-articular components may be prominent determinants of joint position sense. [Orthopedics. 2024;47(3):e114-e118.].

Applying models of care for total hip and knee arthroplasty: External validation of a published predictive model to identify extended stay risk prior to lower-limb arthroplasty

OBJECTIVE

This study aimed to externally validate a reported model for identifying patients requiring extended stay following lower limb arthroplasty in a new setting.

DESIGN

External validation of a previously reported prognostic model, using retrospective data.

SETTING

Medium-sized hospital orthopaedic department, Australia.

PARTICIPANTS

Electronic medical records were accessed for data collection between Sep-2019 and Feb-2020 and retrospective data extracted from 200 randomly selected total hip or knee arthroplasty patients.

INTERVENTION

Participants received total hip or knee replacement between 2-Feb-16 and 4-Apr-19. This study was a non-interventional retrospective study.

MAIN MEASURES

Model validation was assessed with discrimination, calibration on both original and adjusted forms of the candidate model. Decision curve analysis was conducted on the outputs of the adjusted model to determine net benefit at a predetermined decision threshold (0.5).

RESULTS

The original model performed poorly, grossly overestimating length of stay with mean calibration of -3.6 (95% confidence interval -3.9 to -3.2) and calibration slope of 0.52. Performance improved following adjustment of the model intercept and model coefficients (mean calibration 0.48, 95% confidence interval 0.16 to 0.80 and slope of 1.0), but remained poorly calibrated at low and medium risk threshold and net benefit was modest (three additional patients per hundred identified as at-risk) at the a-priori risk threshold.

CONCLUSIONS

External validation demonstrated poor performance when applied to a new patient population and would provide limited benefit for our institution. Implementation of predictive models for arthroplasty should include practical assessment of discrimination, calibration and net benefit at a clinically acceptable threshold.

Early Discharge for Revision Total Knee and Hip Arthroplasty: Predictors of Success

BACKGROUND

The rate of revision total joint arthroplasties is expected to increase drastically in the near future. Given the recent pandemic, there has been a general push toward early discharge. This study aimed to assess for predictors of early postoperative discharge after revision total knee arthroplasty (rTKA) and revision total hip arthroplasty (rTHA).

METHODS

There were 77 rTKA and 129 rTHA collected between January 1, 2019 and December 31, 2021. Demographic data, comorbidities, a comorbidity index, the modified frailty index (mFI-5), and surgical history were collected. The Common Procedural Terminology codes for each case were assessed. Patients were grouped into 2 cohorts, early discharge (length of stay [LOS] <24 hours) and late discharge (LOS >24 hours).

RESULTS

In the rTHA cohort, age >65 years, a history of cardiac or liver disease, an mFI-5 of >1, a comorbidity index of >2.7, a surgical time >122 minutes, and the need for a transfusion were predictors of prolonged LOS. Only the presence of a surgical time of >63 minutes or an mFI-5 >1 increased patient LOS in the rTKA cohort. In both rTHA and rTKA patients, periprosthetic joint infection resulted in a late discharge for all patients, mean 4.8 and 7.1 days, respectively. Dual component revision was performed in 70.5% of rTHA. Only 27.6% of rTKA were 2-component revisions or placements of an antibiotic spacer.

CONCLUSIONS

Several patient and surgical factors preclude early discharge candidacy. For rTHA, an mFI-5 of >2/5, comorbidity index of >4, or a surgical time of >122 minutes is predictive of prolonged LOS. For rTKA, an mFI-5 of >2/5, Charlson Comorbidity Index of >5, or a surgical time of >63 minutes predicts prolonged LOS.

Pain management after total hip arthroplasty: comparative study of analgesic efficacy and tolerability between oral tramadol/dexketoprofen and injectable paracetamol + tramadol

BACKGROUND

Multimodal analgesia for total hip arthroplasty (THA) is increasingly employed to reduce early postoperative pain and promote fast patient discharge. The aim of this study was to compare the efficacy and tolerability of tramadol/dexketoprofen (TRAM/DKP, Group A) versus paracetamol + tramadol (PARA+TRAM, Group B) in patients undergoing THA using minimally invasive direct anterior approach (DAA).

METHODS

A single-centre, randomised, single-blind, parallel, interventional study conducted in 323 patients undergoing primary THA with DAA was performed. Group A consisted of 188 patients and Group B of 135. The primary endpoints were the change from baseline (measured 2 hours postoperatively) in pain intensity (PI) during the treatment period (48 hours), assessed by visual analogue scale (VAS) at pre-specified postoperative time-points (2, 8, 24, 48 hours) and the total rescue medication (RM) use during the first 24 hours postoperatively.

RESULTS

As early as 2 hours after baseline, Group A showed a greater PI reduction from baseline compared to Group B (-26.24% vs. -6.87%; p < 0.001). A lower mean PI (VAS) score was consistently found over the entire observation period following treatment with TRAM/DKP than with PARA+TRAM as well as more than 2-fold higher proportion of responders at the end of treatment period. More patients in Group B required RM in comparison to those in Group A (15.6% vs. 3.7%, p < 0.001). Both treatments were well tolerated.

CONCLUSIONS

After THA, oral TRAM/DKP provides faster and greater pain relief when compared to intravenous PARA+TRAM with limited consumption of RM and favourable tolerability profile. Our study expands the use of TRAM/DKP in the setting of major orthopaedic surgeries.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov (NCT04178109).

Long-term cognitive outcome after elective hip or knee total joint arthroplasty: A population-based observational study

BACKGROUND

One year after elective hip or knee total joint arthroplasty (TJA), >30% of older adults meet criteria for postoperative neurocognitive disorder. However, this is not contextualized with long-term cognitive outcomes in comparable surgical and nonsurgical controls. We analyzed population-based data to compare long-term cognitive outcomes in older adults after TJA, other surgeries, and with and without arthritis pain.

METHODS

This was a retrospective observational analysis of United States older adults in the Health and Retirement Study (HRS) who underwent elective TJA, or elective surgery without expected functional benefits (e.g., cholecystectomy; inguinal herniorrhaphy), between 1998 and 2018 at aged 65 or older. TJA recipients were also age- and sex-matched to nonsurgical controls who reported moderate-severe arthritic pain or denied pain, so that comparison groups included surgical and nonsurgical (pain-suffering and pain-free) controls. We modeled biennially-assessed memory performance, a measure of direct and proxy cognitive assessments, before and after surgery, normalized to the rate of memory decline ("cognitive aging") in controls to express effect size estimates as excess, or fewer, months of memory decline. We used linear mixed effects models adjusted for preoperative health and demographic factors, including frailty, flexibly capturing time before/after surgery (knots at -4, 0, 8 years; discontinuity at surgery).

RESULTS

There were 1947 TJA recipients (average age 74; 63% women; 1358 knee, 589 hip) and 1631 surgical controls (average age 76; 38% women). Memory decline 3 years after TJA was similar to surgical controls (5.2 [95% confidence interval, CI -1.2 to 11.5] months less memory decline in the TJA group, p = 0.11) and nonsurgical controls. At 5 years, TJA recipients experienced 5.0 [95% CI -0.9 to 10.9] months less memory decline than arthritic pain nonsurgical controls.

CONCLUSION

There is no systematic accelerated memory decline at 3 years after TJA compared with surgical or nonsurgical controls.

Factors affecting operating room scheduling accuracy for primary and revision total hip arthroplasty: a retrospective study

INTRODUCTION

Optimizing operating room (OR) scheduling accuracy is important for OR efficiency, meeting patient expectations, and maximizing value for health systems. However, limited data exist on factors influencing the precision of Total Hip Arthroplasty (THA) OR scheduling. This study aims to identify the factors influencing the accuracy of OR scheduling for THA.

METHODS

A retrospective review of 6,072 THA (5,579 primary THA and 493 revision THA) performed between January 2020 and May 2023 at an urban, academic institution was conducted. We collected baseline patient characteristics, surgeon years of experience, and compared actual wheels in to wheels out (WIWO) OR time against scheduled OR time. Significant scheduling inaccuracies were defined as actual OR times deviating by at least 15% from scheduled OR times. Logistic regression analyses were employed to assess the impact of patient, surgeon, and intraoperative factors on OR scheduling accuracy.

RESULTS

Using adjusted odds ratios, primary THA patients who had a lower BMI and surgeons who had less than 10 years of experience were associated with overestimation of OR time. Whereas, higher BMI, younger age, general anesthesia, non-primary osteoarthritis indications, and afternoon procedure start times were linked to underestimation of OR time. For revision THA, lower BMI and fewer components revised correlated with overestimated OR time. Men, higher BMI, more components revised, septic indication for surgery, and morning procedure start times were associated with underestimation of OR time.

CONCLUSION

This study highlights several critical patient, surgeon, and intraoperative factors influencing OR scheduling accuracy for THA. OR scheduling models should consider these factors to enhance OR efficiency.

Did the Comprehensive Care for Joint Replacement Bundled Payment Program Impact Sex Disparities in Total Hip and Knee Arthroplasties?

BACKGROUND

Sex disparities have been noted across various aspects of total hip/knee arthroplasty (THA/TKA). Given incentives to standardize care, bundled payment initiatives including the Comprehensive Care for Joint Replacement (CJR) program may reduce disparities. This study aimed to assess the CJR program's impact on sex disparities in THA/TKA care and outcomes.

METHODS

This retrospective cohort study included 259,673 THAs (61.7% women) and 506,311 TKAs (64.0% women) from a large national database (2013 to 2017). Sex disparities were assessed for care and outcomes related to the period (1) before surgery, (2) during hospitalization for THA/TKA, and (3) after discharge. Disparities were reported as women:men ratios. Difference-in-differences analyses estimated the impact of the CJR program on pre-existing sex disparities.

RESULTS

For both THA and TKA, women were less likely than men to present with a Charlson-Deyo comorbidity index >0 (women:men ratio 0.88 to 0.92), but were more likely to require blood transfusions (women:men ratio 1.48 to 1.79) and be discharged to institutional postacute care (women:men ratio 1.50 to 1.66). Difference-in-differences models demonstrated that the CJR bundled payment program reduced sex disparities in institutional postacute care discharges (THA: -2.28%; 95% confidence interval [CI] -4.20 to -0.35%, P = .02; TKA: -2.07%; 95% CI -3.93 to -0.20%; P = .03) and THA 90-day readmissions (-1.00%, 95% CI -1.88 to -0.13%, P = .02), indicating a differential impact of CJR in women versus men for some outcomes.

CONCLUSIONS

While sex disparities in THA/TKA persist, the CJR program demonstrates potential to impact such differences. Future research should focus on how potential mechanisms could be leveraged to reduce disparities.

New CMS Merit-Based Incentive Payment System Value Pathway After Total Knee and Hip Arthroplasty: Preparing for Mandatory Reporting

This article discusses the implementation of a new Merit-Based Incentive Payment System Value Pathway (MVPs) applicable to elective total hip and total knee arthroplasty as created by Medicare and Medicaid Services (CMS) - the Improving Care for Lower Extremity Joint Repair MVP (MVP ID: G0058). We describe specific quality measures, surgeon-hospital collaborations, future developments with Quality Payment Program, and how lessons from early implementation will empower clinicians to participate in the refining of this MVP. The CMS has designed MVPs as a subset of measures relevant to a specialty or medical condition, in an effort to reduce the burden of reporting and improve assessment of care quality. Physicians and payors must be mindful of detrimental effects these measures in their current form may have on surgeons, institutions, and patients, including disincentivizing care for sicker or more vulnerable populations, and increased administrative costs. Early voluntary participation is crucial to gain valuable experience for the orthopedic community and in an effort to work alongside CMS to maximize care while minimizing cost for patients and burden for providers.

Health status after periprosthetic proximal femoral fractures

Aims

Periprosthetic proximal femoral fractures (PFFs) are a major complication after total hip arthroplasty (THA). Health status after PFF is not specifically investigated. The aim of this study is to evaluate the health status pattern over two years after sustaining a PFF.

Methods

A cohort of patients with PFF after THA was derived from the Brabant Injury Outcomes Surveillance (BIOS) study. The BIOS study, a prospective, observational, multicentre follow-up cohort study, was conducted to obtain data by questionnaires pre-injury and at one week, and one, three, six, 12, and 24 months after trauma. Primary outcome measures were the EuroQol five-dimension three-level questionnaire (EQ-5D-3L), the Health Utility Index 2 (HUI2), and the Health Utility Index 3 (HUI3). Secondary outcome measures were general measurements such as duration of hospital stay and mortality.

Results

A total of 70 patients with a PFF were included. EQ-5D utility scores were significantly lower on all timepoints except at six months' follow-up compared to pre-injury. EuroQol visual analogue scale (EQ-VAS) scores at one month's follow-up were significantly lower compared to pre-injury. The percentage of reported problems at two years was higher for all dimensions except anxiety/depression when compared to pre-injury. The mean EQ-5D utility score was 0.26 higher in males compared to females (95% confidence interval (CI) 0.01 to 0.42; p = 0.003). The mean EQ-VAS score for males was 8.9 points higher when compared to females over all timepoints (95% CI 1.2 to 16.7; p = 0.027). Mortality was 10% after two years' follow-up.

Conclusion

PFF patients are a frail population with substantial functional impairment at baseline. Post-injury, they have a significant and clinically relevant lower health status two years after trauma when compared to pre-injury. Health status improves the most between one and three months after injury. Two years after PFF, more patients experience problems in mobility, self-care, usual activities, and pain/discomfort than pre-injury.

The Impact of Preoperative Medical Evaluation in an Orthopaedic Perioperative Medical Clinic on Total Joint Arthroplasty Outcomes: An Observational Study

BACKGROUND

A preoperative medical evaluation (PME) in total joint arthroplasty (TJA) is routine despite considerable variation and uncertainty regarding its benefits. The orthopaedic department in our academic health system established a perioperative medical clinic (PMC) to standardize perioperative management and to study the effect of this intervention on total hip arthroplasty (THA) and total knee arthroplasty (TKA) outcomes. This observational study compared the impact of a PME within 30 days prior to surgery at the PMC (Periop30) versus elsewhere ("Usual Care") on postoperative length of stay (LOS), extended LOS (i.e., a stay of >3 days), and Patient-Reported Outcomes Measurement Information System-10 (PROMIS-10) Global Physical Health (GPH) score improvement in TJA.

METHODS

We stratified adult patients (≥18 years of age) who underwent primary TJA between January 2015 and December 2020 into Periop30 or Usual Care. We utilized univariate tests (a chi-square test for categorical variables and a t test for continuous variables) to assess for differences in patient characteristics. For both TKA and THA, LOS was assessed with use of multivariable negative binomial regression models; extended LOS, with use of binary logistic regression; and PROMIS-10 GPH score, with use of mixed-effects models with random intercept and slope. Interaction terms between the focal predictor (Periop30, yes or no) and year of surgery were included in all models.

RESULTS

Periop30 comprised 82.3% of TKAs (1,911 of 2,322 ) and 73.8% of THAs (1,876 of 2,541). For THA, the Periop30 group tended to be male (p = 0.005) and had a higher body mass index (p = 0.001) than the Usual Care group. The Periop30 group had a higher rate of staged bilateral THA (10.6% versus 7.5%; p = 0.028) and a lower rate of simultaneous bilateral TKA (5.1% versus 12.2%; p < 0.001) than the Usual Care group. Periop30 was associated with a lower mean LOS for both TKA (43.46 versus 54.15 hours; p < 0.001) and THA (41.07 versus 57.94 hours; p < 0.001). The rate of extended LOS was lower in the Periop30 group than in the Usual Care group for both TKA (15% versus 26.5%; p < 0.001) and THA (13.3% versus 27.4%; p < 0.001). There was no significant difference in GPH score improvement between Periop30 and Usual Care for either TKA or THA.

CONCLUSIONS

Periop30 decreased mean LOS and the rate of extended LOS for TJA without an adverse effect on PROMIS-10 GPH scores.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Phantom validation of a novel RSA-based impingement metric to assess component-on-component impingement risk

Component-on-component impingement in total hip arthroplasty may lead to post-operative complications including dislocation. Despite numerous clinical studies focusing on reducing this risk, assessment methods remain limited to qualitative radiography, finite element analysis, and cadaver studies. There is a need for more precise measurements of impingement in the research setting. We aimed to validate a novel RSA-based impingement metric to measure component-on-component impingement in vivo. A phantom experiment of a standard metal-on-polyethylene total hip system was performed. RSA examinations were performed as typical for a traditional weight-bearing RSA exam for large joints. The phantom was placed in 10 possible impinged positions and one neutral position. Double exposure radiographs were taken to measure repeatability. The closest distance between the skirt of the head and the inner circumference of the acetabular cup liner was measured to assess impingement risk. Distances between the closest point of the hood to the edge of the cup in 10 impinged positions ranged from 0.05 to 1.03 mm, with the average being 0.67 mm. In the neutral position, the distance measured is 11.02 mm. Excellent repeatability was observed, with a standard deviation of 0.03 mm with an r value of 0.09. A validated RSA-based risk metric was established to evaluate in vivo hip impingement. A 1 mm threshold may be proposed to define impingement where distances approaching 1.00 mm are at a greater risk of impingement. This simplified metric holds promise for upcoming clinical studies on component-on-component impingement.

Patient reported outcome measures (PROMs) as primary and secondary outcomes in total hip and knee arthroplasty randomized controlled trials: a systematic review

BACKGROUND

Significant heterogeneity exists regarding patient reported outcome measures (PROMs) used in total hip (THA) and knee (TKA) arthroplasty randomized controlled trials (RCTs). This study investigates the PROMs used as primary and secondary outcomes in contemporary arthroplasty RCTs.

METHODS

A literature search identified THA and TKA RCTs that were published in top ten impact factor orthopaedic journals from 2017 to 2021. Screening identified 241 trials: 76 THA, 157 TKA, and eight combined. Data were extracted to identify PROMs utilized as either primary or secondary outcomes and the time period of measurement.

RESULTS

Visual Analog Scale (VAS) Pain was the most reported primary PROM in THA (9.2%) and TKA (22.9%) trials. This was followed by Numeric Rating Scale (NRS) Pain (7.9%) and the Harris Hip score (6.6%) in THA trials and NRS Pain (4.5%) and the Knee Society score (4.5%) in TKA trials. Many THA (37.0%) and TKA (52.1%) trials did not clearly specify primary outcome time points. Only pain scales were reported at time points less than one week, while various joint-specific functional outcomes were reported at later time points. As secondary outcomes, the Harris Hip score (28.9%) was most common in THA trials and the Knee Society score (26.1%) was most common in TKA trials. Indeterminate primary or secondary outcomes were reported in 18.2% of studies.

CONCLUSIONS

Contemporary THA and TKA trials exhibit heterogeneity of PROMs as study outcomes after the first postoperative week. Our findings highlight the need for consensus in PROM reporting and better methodological reporting to improve the interpretability of RCT outcomes.

PROSPERO REGISTRATION NUMBER

CRD42022337255.

The impact of femoral head size on the wear evolution at contacting surfaces of total hip prostheses: A finite element analysis

Total Hip Arthroplasty has been a revolutionary technique in restoring mobility to patients with damaged hip joints. The introduction of modular components of the hip prosthesis allowed for bespoke solutions based on the requirements of the patient. The femoral stem is designed with a conical trunnion to allow for assembly of different femoral head sizes based on surgical requirements. The femoral head diameters for a metal-on-polyethylene hip prosthesis have typically ranged between 22 mm and 36 mm and are typically manufactured using Cobalt-Chromium alloy. A smaller femoral head diameter is associated with lower wear of the polyethylene, however, there is a higher risk of dislocation. In this study, a finite element model of a standard commercial hip arthroplasty prosthesis was modelled with femoral head diameters ranging from 22 mm to 36 mm to investigate the wear evolution and material loss at both contacting surfaces (acetabular cup and femoral stem trunnion). The finite element model, coupled with a validated in-house wear algorithm modelled a human walking for 10 million steps. The results have shown that as the femoral head size increased, the amount of wear on all contacting surfaces increased. As the femoral head diameter increased from 22 mm to 36 mm, the highly cross-linked polyethylene (XLPE) volumetric wear increased by 61% from 98.6 mm3 to 159.5 mm3 while the femoral head taper surface volumetric wear increased by 21% from 4.18 mm3 to 4.95 mm3. This study has provided an insight into the amount of increased wear as the femoral head size increased which can highlight the life span of these prostheses in the human body.

A Cautionary Tale: Malaligned Incentives in Total Hip and Knee Arthroplasty Payment Model Reforms Threaten Promising Innovation and Access to Care

Over the past several years, there have been notable changes and controversies involving Medicare reimbursement for total hip (THA) and total knee arthroplasty (TKA). We have seen the development and implementation of experimental bundled payment model pilot programs goals of improving quality and decreasing overall costs of care during the last decade. Many orthopaedic surgeons have embraced these programs and have demonstrated the ability to succeed in these new models by implementing strategies, such as preservice optimization, to shift care away from inpatient or postdischarge settings and reduce postoperative complications. However, these achievements have been met with continual reductions in surgeon reimbursement rates, lower bundle payment target pricings, modest increases in hospital reimbursement rates, and inappropriate valuations of THA and TKA Common Procedural Terminology (CPT) codes. These challenges have led to an organized advocacy movement and spurred research involving the methods by which improvements have been made throughout the entire episode of arthroplasty care. Collectively, these efforts have recently led to a novel application of CPT codes recognized by payers to potentially capture presurgical optimization work. In this paper, we present an overview of contemporary payment models, summarize notable events involved in the review of THA and TKA CPT codes, review recent changes to THA and TKA reimbursement, and discuss future challenges faced by arthroplasty surgeons that threaten access to high-quality THA and TKA care.

"Off-Hour" Surgical Start Times Do Not Influence Surgical Precision and Outcomes in Middle-aged Patients and Patients 65 Years and Older With Hip Fractures

BACKGROUND

Previous studies show the "off-hour" effect impacts outcomes after surgery in non-orthopedic settings. This study assessed if the off-hour effect impacts surgical precision and outcomes in middle-aged patients and patients 65 years and older with hip fractures.

MATERIALS AND METHODS

All operative patients in an academic medical center's institutional review board-approved hip fracture registry were reviewed for demographics, hospital quality measures, operative details, radiographic parameters, and outcomes. Patients were grouped into standard (7 am to 4:59 pm) and off-hour (5 pm to 6:59 am) cohorts depending on surgical start time and comparative analyses were conducted. Two subanalyses were conducted: one comparing the quality of reduction for patients with intertrochanteric hip fractures and another comparing the rates of inpatient transfusion and postoperative dislocation for patients treated with arthroplasty.

RESULTS

A total of 2334 patients underwent operative treatment. The off-hour cohort had hospital quality measures and outcomes similar to the standard cohort, including length of stay, rates of inpatient complication, mortality, and readmission. Sub-analysis of 814 intertrochanteric hip fractures demonstrated similar tip-apex distance, residual calcar step-off, and post-fixation neck-shaft angle, while subanalysis of 713 patients undergoing arthroplasty showed similar rates of transfusion and dislocation between cohorts.

CONCLUSION

The time of day patients undergo hip fracture repair does not affect surgical outcomes or hospital quality measures. These results highlight the need for standardized hip protocols and treatment pathways to provide equitable care at all hours of the day. [Orthopedics. 2024;47(3):185-191.].

Specimen-specific finite element representations of implanted hip capsules

The hip capsule is a ligamentous structure that contributes to hip stability. This article developed specimen-specific finite element models that replicated internal-external (I-E) laxity for ten implanted hip capsules. Capsule properties were calibrated to minimize root mean square error (RMSE) between model and experimental torques. RMSE across specimens was 1.02 ± 0.21 Nm for I-E laxity and 0.78 ± 0.33 Nm and 1.10 ± 0.48 Nm during anterior and posterior dislocation, respectively. RMSE for the same models with average capsule properties was 2.39 ± 0.68 Nm. Specimen-specific models demonstrated the importance of capsule tensioning in hip stability and have relevance for surgical planning and evaluation of implant designs.

Device-Measured Physical Activity in 3506 Individuals with Knee or Hip Arthroplasty

PURPOSE

Hip and knee arthroplasty aims to reduce joint pain and increase functional mobility in patients with osteoarthritis; however, the degree to which arthroplasty is associated with higher physical activity is unclear. The current study sought to assess the association of hip and knee arthroplasty with objectively measured physical activity.

METHODS

This cross-sectional study analyzed wrist-worn accelerometer data collected in 2013-2016 from UK Biobank participants (aged 43-78 yr). Multivariable linear regression was performed to assess step count, cadence, overall acceleration, and activity behaviors between nonarthritic controls, end-stage arthritic, and postoperative cohorts, controlling for demographic and behavioral confounders. From a cohort of 94,707 participants with valid accelerometer wear time and complete self-reported data, electronic health records were used to identify 3506 participants having undergone primary or revision hip or knee arthroplasty and 68,389 nonarthritic controls.

RESULTS

End-stage hip or knee arthritis was associated with taking 1129 fewer steps per day (95% confidence interval (CI), 811-1447; P < 0.001) and having 5.8 fewer minutes per day (95% CI, 3.0-8.7; P < 0.001) of moderate-to-vigorous activity compared with nonarthritic controls. Unilateral primary hip and knee arthroplasties were associated with 877 (95% CI, 284-1471; P = 0.004) and 893 (95% CI, 232-1554; P = 0.008) more steps than end-stage osteoarthritic participants, respectively. Postoperative unilateral hip arthroplasty participants demonstrated levels of moderate-to-vigorous physical activity and daily step count equivalent to nonarthritic controls. No difference in physical activity was observed between any cohorts in terms of overall acceleration, or time spent in daily light activity, sedentary behavior, or sleep.

CONCLUSIONS

Hip and knee arthroplasties are associated with higher levels of physical activity compared with participants with end-stage arthritis. Unilateral hip arthroplasty patients, in particular, demonstrate equivalence to nonarthritic peers at more than 1 yr after surgery.

Increased patient body mass index is associated with increased surgeon physiologic stress during total hip arthroplasty

INTRODUCTION

While increased body mass index (BMI) in patients undergoing total hip arthroplasty (THA) increases surgical complexity, there is a paucity of objective studies assessing the impact of patient BMI on the cardiovascular stress experienced by surgeons during THA. The aim of this study was to assess the impact of patient BMI on surgeon cardiovascular strain during THA.

METHODS

We prospectively evaluated three fellowship-trained arthroplasty surgeons performing a total of 115 THAs. A smart-vest worn by the surgeons recorded mean heart rate, stress index (correlate of sympathetic activation), respiratory rate, minute ventilation, and energy expenditure throughout the procedures. Patient demographics as well as perioperative data including surgical approach, surgery duration, number of assistants, and the timing of the surgery during the day were collected. Linear regression was utilized to assess the impact of patient characteristics and perioperative data on cardiorespiratory metrics.

RESULTS

Average surgeon heart rate, energy expenditure, and stress index during surgery were 98.50 beats/min, 309.49 cal/h, and 14.10, respectively. Higher patient BMI was significantly associated with increased hourly energy expenditure (P = 0.027), mean heart rate (P = 0.037), and stress index (P = 0.027) independent of surgical approach. Respiratory rate and minute ventilation were not associated with patient BMI. The number of assistants and time of surgery during the day did not impact cardiorespiratory strain on the surgeon.

CONCLUSION

The physiologic burden on surgeons during primary THA significantly increases as patient BMI increases. This study suggests that healthcare systems should consider adjusting reimbursement models to account for increased surgeon workload due to obesity. Further surgeons should adopt strategies in operative planning and case scheduling to handle this added physical strain.

LEVEL OF EVIDENCE

III.

Computer-based analysis of the taper connection strength of different revision head and adapter sleeve designs

OBJECTIVES

Ceramic revision heads, equipped with titanium adapter sleeves, are used in femoral head revision in total hip arthroplasty to avoid ceramic fracture due to the damaged taper.

METHODS

A finite element analysis of the taper connection strength of revision heads with varying head diameters combined with adapter sleeves of different lengths was conducted. The influence of various assembly forces, head diameter, and length of the adapter sleeves was evaluated. For two combinations, the pattern of contact pressure was evaluated when applying a simplified joint load (3 kN, 45° load angle). Experimental validation was conducted with 36 mm heads and adapter sleeves in size S, as well as 28 mm heads and adapter sleeves in size XL.

RESULTS

The pull-off force increased with higher assembly forces. Using larger head diameters and adapter sleeves led to decreased pull-off forces, a reduced contact surface, and less contact pressure. The contact pressure showed significant peaks and a diagonal pattern under 45° angle loading when assembly forces were less than 4 kN, and larger adapter sleeves were utilized.

CONCLUSION

A sufficient assembly force should be ensured intraoperatively, especially with an increasing head diameter and adapter sleeve size, as lower assembly forces might lead to reduced taper connection strength.

Impact of sarcopenia in elderly patients undergoing elective total hip arthroplasty on postoperative outcomes: a propensity score-matched study

OBJECTIVE

Frailty poses a crucial risk for postoperative complications in the elderly, with sarcopenia being a key component. The impact of sarcopenia on postoperative outcomes after total hip arthroplasty (THA) is still unclear. This study investigated the potential link between sarcopenia and postoperative outcomes among elderly THA patients.

METHODS

Totally 198 older patients were enrolled in this study. Sarcopenia in this group was determined by assessing the skeletal muscle index, which was measured using computed tomography at the 12th thoracic vertebra and analyzed semi-automatically with MATLAB R2020a. Propensity score matching (PSM) was employed to evaluate postoperative complications of grade II and above (POCIIs).

RESULTS

The variables balanced using PSM contained age, sex and comorbidities including hypertension, diabetes, hyperlipidemia and COPD. Before PSM, sarcopenic patients with reduced BMI (24.02 ± 0.24 vs. 27.11 ± 0.66, P < 0.001) showed higher POCIIs rates (48.31% vs. 15%, P = 0.009) and more walking-assisted discharge instances (85.96% vs. 60%, P = 0.017) compared with non-sarcopenia patients. After PSM, this group maintained reduced BMI (23.47 ± 0.85 vs. 27.11 ± 0.66, P = 0.002), with increased POCIIs rates (54.41% vs. 15%, P = 0.002) and heightened reliance on walking assistance at discharge (86.96% vs. 60%, P = 0.008).

CONCLUSION

Sarcopenia patients exhibited a higher incidence of POCIIs and poorer physical function at discharge. Sarcopenia could serve as a valuable prognostic indicator for elderly patients undergoing elective THA.

Protocol for a prospective multicentre cohort study to address the question whether diabetes and its management is still a risk factor in fast-track joint arthroplasty

INTRODUCTION

Perioperative glycaemic control is important. However, the complexity of guidelines for perioperative diabetes management is complicated due to different and novel antihyperglycaemic medications, limited procedure-specific data and lack of data from implemented fast-track regimens which otherwise are known to reduce morbidity and glucose homeostasis disturbances. Consequently, outcome in patients with diabetes mellitus (DM) after surgery and the influence of perioperative diabetes management on postoperative recovery remains poorly understood.

METHODS AND ANALYSIS

A prospective observational multicentre study involving 8 arthroplasty centres across Denmark with a documented implemented fast-track programme (median length of hospitalisation (LOS) 1 day). We will collect detailed perioperative data including preoperative haemoglobin A1c and antidiabetic treatment in 1400 unselected consecutive patients with DM undergoing hip and knee arthroplasty from September 2022 to December 2025, enrolled after consent. Follow-up duration is 90 days after surgery. The primary outcome is the proportion of patients with DM with LOS >4 days and 90-day readmission rate after fast-track total hip arthroplasty (THA), total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). The secondary outcome is the association between perioperative diabetes treatment and LOS >2 days, 90-day readmission rate, other patient demographics and Comprehensive Complication Index for patients with DM after THA/TKA/UKA in a fast-track regimen.

ETHICS AND DISSEMINATION

The study will follow the principles of the Declaration of Helsinki and ICH-Good Clinical Practice guideline. Ethical approval was not necessary as this is a non-interventional observational study on current practice. The trial is registered in the Region of Southern Denmark and on ClinicalTrials.gov. The main results and all substudies of this trial will be published in peer-reviewed international medical journals.

TRIAL REGISTRATION NUMBER

NCT05613439.

Cohort profile: Worldwide Collaboration on OsteoArthritis prediCtion for the Hip (World COACH) - an international consortium of prospective cohort studies with individual participant data on hip osteoarthritis

PURPOSE

Hip osteoarthritis (OA) is a major cause of pain and disability worldwide. Lack of effective therapies may reflect poor knowledge on its aetiology and risk factors, and result in the management of end-stage hip OA with costly joint replacement. The Worldwide Collaboration on OsteoArthritis prediCtion for the Hip (World COACH) consortium was established to pool and harmonise individual participant data from prospective cohort studies. The consortium aims to better understand determinants and risk factors for the development and progression of hip OA, to optimise and automate methods for (imaging) analysis, and to develop a personalised prediction model for hip OA.

PARTICIPANTS

World COACH aimed to include participants of prospective cohort studies with ≥200 participants, that have hip imaging data available from at least 2 time points at least 4 years apart. All individual participant data, including clinical data, imaging (data), biochemical markers, questionnaires and genetic data, were collected and pooled into a single, individual-level database.

FINDINGS TO DATE

World COACH currently consists of 9 cohorts, with 38 021 participants aged 18-80 years at baseline. Overall, 71% of the participants were women and mean baseline age was 65.3±8.6 years. Over 34 000 participants had baseline pelvic radiographs available, and over 22 000 had an additional pelvic radiograph after 8-12 years of follow-up. Even longer radiographic follow-up (15-25 years) is available for over 6000 of these participants.

FUTURE PLANS

The World COACH consortium offers unique opportunities for studies on the relationship between determinants/risk factors and the development or progression of hip OA, by using harmonised data on clinical findings, imaging, biomarkers, genetics and lifestyle. This provides a unique opportunity to develop a personalised hip OA risk prediction model and to optimise methods for imaging analysis of the hip.

Phosphaturic mesenchymal tumor-induced bilateral osteomalacia femoral neck fractures: a case report

Phosphaturic mesenchymal tumors (PMT) are rare and distinctive tumors that typically result in paraneoplastic syndrome known as tumor-induced osteomalacia (TIO). We report a case of bilateral osteoporotic femoral neck fracture caused by PMT. PMT was surgically resected, followed by sequential treatment of bilateral femoral neck fractures with total hip arthroplasty (THA). A 49-year-old perimenopausal woman experienced consistent bone pain with limb weakness persisting for over 2 years. Initially, she was diagnosed with early osteonecrosis of the femoral head and received nonsurgical treatment. However, from 2020 to 2022, her pain extended to the bilateral shoulders and knees with increased intensity. She had no positive family history or any other genetic diseases, and her menstrual cycles were regular. Physical examination revealed tenderness at the midpoints of the bilateral groin and restricted bilateral hip range of motion, with grade 3/5 muscle strength in both lower extremities. Laboratory findings revealed moderate anemia (hemoglobin 66 g/L), leukopenia (2.70 × 109/L), neutropenia (1.28 × 109/L), hypophosphatemia (0.36 mmol/L), high alkaline phosphatase activity (308.00 U/L), and normal serum calcium (2.22 mmol/L). After surgery, additional examinations were performed to explore the cause of hypophosphatemic osteomalacia. After definitive diagnosis, the patient underwent tumor resection via T11 laminectomy on August 6, 2022. Six months after the second THA, the patient regained normal gait with satisfactory hip movement function without recurrence of PMT-associated osteomalacia or prosthesis loosening. By providing detailed clinical data and a diagnostic and treatment approach, we aimed to improve the clinical understanding of femoral neck fractures caused by TIO.

[Effectiveness analysis of revision surgery after total hip arthroplasty assisted by artificial intelligence preoperative planning system]

Objective

To explore the short-term effectiveness of hip revision surgery guided by artificial intelligence preoperative planning (AIHIP) system.

Methods

The clinical data of 22 patients (23 hips) who were admitted between June 2019 and March 2023 and met the selection criteria were retrospectively analyzed. There were 12 males and 10 females with an average age of 69.7 years (range, 44-90 years). There were 19 hips in the first revision, 3 hips in the second revision, and 1 hip in the third revision. The causes of revision included 12 hips with prosthesis loosening, 4 hips with acetabular cup loosening, 3 hips with osteolysis, 2 hips with acetabular dislocation, 1 hip with postoperative infection, and 1 hip with prosthesis wear. There were 6 hips in stage ⅡA, 9 hips in stage ⅡB, 4 hips in stage ⅡC, 3 hips in stage ⅢA, and 1 hip in stage ⅢB according to Paprosky staging of acetabular bone defect. The replacement of prosthesis type, operation time, hospitalization stay, ground active condition, and postoperative infection, fracture, prosthesis loosening, and other adverse events were recorded. The function of the affected limb was evaluated by Harris score before operation, at 1 week and 6 months after operation, and the range of motion of the hip joint was compared before operation and at 6 months after operation.

Results

The operation time was 85-510 minutes, with an average of 241.8 minutes; the hospitalization stay was 7-35 days, with an average of 15.2 days; the time of disassociation from the walker was 2-108 days, with an average of 42.2 days. All the 22 patients were followed up 8-53 months (mean, 21.7 months). No adverse events such as prosthesis loosening or infection occurred in the rest of the patients, except for postoperative hematoma of the thigh in 1 patient and dislocation of the hip in 1 hip. The matching degree of acetabular cup was completely matched in 22 hips and mismatched in 1 hip (+2), the matching rate was 95.65%. The matching degree of femoral stem was completely matched in 22 hips and generally matched in 1 hip (-1), and the matching rate was 100%. The Harris scores were 55.3±9.8 and 89.6±7.2 at 1 week and 6 months after operation, respectively, which significantly improved when compared with before operation (33.0±8.6, P<0.05), and further improved at 6 months after operation than at 1 week after operation ( P<0.05). The function of hip joint was evaluated by Harris score at 6 months after operation, and 21 hips were good and 2 hips were moderate, which could meet the needs of daily life. The range of motion of hip joint was (111.09±10.11)° at 6 months after operation, which was significantly different from (79.13±18.50)° before operation ( t=-7.269, P<0.001).

Conclusion

AIHIP system can improve the accuracy of revision surgery, reduce the difficulty of surgery, and achieve good postoperative recovery and satisfactory short-term effectiveness.

Diagnostic Evaluation of Prosthetic Joint Infections of the Shoulder: What Does the Literature Say?

The total number of patients with a total shoulder arthroplasty (TSA) is increasing, and the number of patients experiencing a (TSA) prosthetic joint infection (PJI) also will increase. It is important that physicians know how to identify signs of infection, know the common pathogens, and know how to work up a shoulder PJI. This publication reviewed the current literature about presenting signs and symptoms, common shoulder pathogens and how they differ from total knee and hip pathogens, and what images, tests, and procedures can aid in identification of infection.

Non-metastatic hip fractures surgery in patients with active cancer: benefit and risk

PURPOSE

Although rare, non-metastatic proximal femoral fracture (PFF) can develop in patients with active cancer. However, little data are available regarding the risks and benefits of surgical treatment in such patients. The purpose of his study was to investigate the risks and benefits of surgical treatment of PFF in patients with and without cancer.

METHODS

We retrospectively examined the medical records of all patients treated for PFF, excluding those with pathological fracture, at our hospital from July 2013 to December 2020. The patients were divided into two groups; The active cancer group and the standard group. We investigated in both groups about surgical and medical complications during the perioperative period, walking ability two weeks postoperatively, and one-year postoperative mortality rate.

RESULT

After the inclusion and exclusion criteria, 39 patients in the active cancer group and 331 patients in the standard group were finally investigated. There were no statistically significant differences between the two groups. The complication rate did not appear statistical significance between two groups (16.7% in active cancer group vs 10.7% in standard group: p = 0.272). Walking ability was also similar in two groups. Mortality rate at one year was significantly higher in the active cancer group. (41.2% in active cancer group vs 6.0% in standard group: p < 0.05).

CONCLUSION

Although the active cancer group had a higher mortality rate at one year, which was influenced by the prognosis of the cancer, the benefits of surgical intervention, such as regaining walking ability, were the same in patients with and without active cancer.

Time-course of heart rate variability after total hip arthroplasty

Heart rate variability (HRV) is a measure of the autonomic nervous system function and possibly related to postoperative outcome. Despite several HRV studies in different surgical settings, optimal indices and timepoints for measuring have not been adequately determined. Consequently, there is a need for detailed descriptive procedure-specific studies on the time-course of perioperative HRV within a modern fast-track surgical setting. We measured HRV continuously in 24 patients from 4 days before until 9 days after total hip arthroplasty (THA). Statistical methods included mainly ANOVA and t-tests or Kruskal-Wallis and pairwise Wilcoxon test. Patients completed the Orthostatic Discriminant and Severity Scale five times during the study describing autonomic nervous system dysfunction. Standard deviation between normal-to-normal beats and the total power of HRV were reduced for at least 9 days following THA, with a trend towards increased HRV leading up to the day of surgery. The balance between low- and high-frequency power of HRV was reduced in the postoperative evenings. There was increased orthostatic intolerance symptoms on the first postoperative day, with symptoms of pain, fatigue and weakness decreasing after the first postoperative day. Median hospital stay was 1 day. We provide the first detailed description of perioperative time-course of HRV and orthostatic symptoms in fast-track THA, showing reduced HRV after surgery for at least a week, and that HRV changes are sensitive to time of day and timing before and after surgery. These results are helpful in designing future HRV studies in perioperative risk assessment and outcome.

The Effect of Waiting for a Primary Total Hip Arthroplasty on the Overall Hip Function and Quality of Life

BACKGROUND

The primary aim was to determine whether time spent awaiting primary total hip arthroplasty (THA) affects patient-reported outcome measures (PROMs) using the Oxford Hip score, Harris Hip Score, and visual analogue scale (VAS) pain. The secondary aim was to assess whether patients have worsening HRQoL, while awaiting THA using the European Quality of Life Five Dimension (EQ-5D) index and EQ-5D health VAS.

METHODS

This was a single center cross-sectional study of 190 patients awaiting THA. Patients were divided into waiting "more than 6 months" and "less than 6 months." Baseline and current scores were compared. Multivariate regression analyses were performed to identify predictors of PROM change.

RESULTS

No significant intergroup differences were observed for change in preoperative Oxford Hip score, Harris Hip Score, and VAS pain from index consultation to time of study. The EQ-5D index and EQ-5D health VAS decreased significantly further in patients waiting more than 6 months (P = .043, P = .004). Time awaiting THA was significantly associated with a decrease in EQ-5D index and EQ-5D health VAS in multivariate regression (P = .013, P < .001).

CONCLUSIONS

Waiting more than 6 months is not associated with a decrease in hip-specific PROMs and longer waiting times are not associated with changes in hip-specific PROMs. Waiting time was associated with a decrease in health-related quality of life and patients waiting more than 6 months had significantly higher decreases in EQ-5D scores. This suggests that living longer with hip osteoarthritis leads to a decrease in QoL, not necessarily through perceived osteoarthritis progression.

LEVEL OF EVIDENCE

Level III cross-sectional study.

Use of interrupted time-series analyses in evaluating health economic outcomes following implementation of multilayer water-tight wound closure in a primary total joint arthroplasty population

Aim: Total joint arthroplasty (TJA) with multi-layer, watertight closure (MLWC) using knotless barbed suture and 2-octyl cyanoacrylate plus polymer mesh tape was compared with conventional closure (CC) using Vicryl™ sutures and staples. Patients & methods: Electronic medical records of patients undergoing TJA (1574: total knee arthroplasty; 580: total hip arthroplasty; 13: unknown) from a single surgeon at a US hospital (CC 2011 to 2013; MLWC 2015 to 2020) were reviewed. Outcomes were length of stay (LOS), discharge to skilled nursing facility (SNF), 90-day surgical site infection (SSI) and 90-day readmission. Logistic regression controlled for baseline characteristics. Adjusted interrupted time series (ITS) analyses accounted for decreasing trends in LOS and SNF discharge over time. Results: Among 2167 TJA cases (mean [standard deviation] age 66.0 [9.7] years, 53.3% female), 906 received CC and 1261 received MLWC. Bivariate analysis showed no statistically significant differences in 90-day SSI rates; however, MLWC patients had 60% lower 90-day readmission rates (1.5 vs 3.8%, p < 0.05), 44% lower LOS (1.4 vs 2.5 days, p < 0.05) and 40% lower discharge rates to a skilled care facility (8.5 vs 14.1%, p < 0.05). Multivariable analyses showed CC patients were 2.45-times more likely to be readmitted within 90 days, 1.88-times more likely to be discharged to SNF and had 1.67-times longer LOS compared with MLWC. ITS analyses showed a sharp decline in LOS (0.9 days) and discharge to SNF (5.6% incidence) after implementation of MLWC, followed by no further changes for the remainder of the study period. Conclusion: MLWC was associated with ≥40% reduction in 90-day readmission, LOS and SNF discharge compared with TJA CC. LOS and discharge rate to SNF declined sharply after the implementation of MLWC.

Statistical analysis of VEXLPE wear against alumina produced by a new 200-station, multidirectional pin-on-disk device

With low wear rates shown by contemporary bearing materials of total hip prostheses, the standard deviation of wear rate is relatively high. Therefore, large sample sizes are needed for an adequate power of test. Because wear tests take a long time, it is practical to test several samples simultaneously. A new high-capacity, multidirectional wear test device, called the SuperCTPOD-200, was introduced. A 3 million-cycle wear test with an unprecedented sample size of 200 was performed for VEXLPE. The duration of the test was 6 weeks. The wear factor was normally distributed with a mean ± SD of 1.64 × 10-7 mm3/Nm ± 0.22 × 10-7 mm3/Nm (n = 200). The observation that SD was 13.1% of the mean can be useful in power analyses of future tests with other highly cross-linked polyethylenes. Burnishing was the most typical feature on the worn pins, which was in agreement with clinical findings on retrieved acetabular liners. The present study emphasizes statistics that often plays a minor role only in wear studies.

Towards an optimal design of a functionally graded porous uncemented acetabular component using genetic algorithm

Generation of polyethylene wear debris and peri‑prosthetic bone resorption have been identified as potential causes of acetabular component loosening in Total Hip Arthroplasty. This study was aimed at optimization of a functionally graded porous acetabular component to minimize peri‑prosthetic bone resorption and polyethylene liner wear. Porosity levels (porosity values at acetabular rim, and dome) and functional gradation exponents (radial and polar) were considered as the design parameters. The relationship between porosity and elastic properties were obtained from numerical homogenization. The multi-objective optimization was carried out using a non-dominated sorting genetic algorithm integrated with finite element analysis of the hemipelvises subject to various loading conditions of common daily activities. The optimal functionally graded porous designs (OFGPs -1, -2, -3, -4, -5) exhibited less strain-shielding in cancellous bone compared to solid metal-backing. Maximum bone-implant interfacial micromotions (63-68 μm) for OFGPs were found to be close to that of solid metal-backing (66 μm), which might facilitate bone ingrowth. However, OFGPs exhibited an increase in volumetric wear (3-10 %) compared to solid metal-backing. The objective functions were found to be more sensitive to changes in polar gradation exponent than radial gradation exponent, based on the Sobol' method. Considering the common failure mechanisms, OFGP-1, having highly porous acetabular rim and less porous dome, appears to be a better alternative to the solid metal-backing.

The Use of Active Coagulation Whole Blood-An Innovative Treatment Strategy for Hard-To-Heal Wounds

BACKGROUND

Deep and tunneling wounds are a challenge to apply and maintain most advanced wound dressings to promote effective healing. An autologous whole blood clot is a topical treatment and has been found to be safe and effective in healing cutaneous wounds. The active coagulation whole blood (ACWB) clot treatment, using the patient's own blood, is used to treat deep and tunneling wounds, by mixing the blood with coagulation components and applying it into the wound cavity allowing the clot to re-form inside the wound. We aimed to explore ACWB treatment in hard-to-heal wounds.

METHODS

5 patients with multiple comorbidities, exhibiting surgical abdominal wound, chronic pilonidal sinus, stage 4 sacral pressure ulcer with exposed bone, post-amputation surgical site wound, and non-healing wound dehiscence at the site of a prior hip replacement, were all treated with the ACWB clot treatment.

RESULTS

Complete wound healing was observed in 4/5 cases. In the fifth case, there was a 70% reduction in the depth and surface area of the abdominal surgical wound.

DISCUSSION

The ACWB treatment was found to be effective in deep wounds with cavities and exposed structures. ACWB, in its flowable form, can effectively provide coverage of the deepest interstices of the wound's cavities by virtue of its liquid properties, forming a fibrin matrix, mimicking the role of the extracellular matrix. The flowable formulation of ACWB treatment safely and efficiently provides coverage of the entirety of the wound surface to improve the time and process of complex wound surface healing.

Pericapsular Nerve Group (PENG) Block Results in Significant Opioid Reduction in Total Hip Arthroplasty: A Retrospective Analysis

PURPOSE

The purpose of this retrospective study was to determine the effectiveness of pericapsular nerve group (PENG) block for pain control intraoperatively in patients undergoing total hip arthroplasty (primary-27130) (THA), compared to opioid based analgesia. The PENG block is an emerging regional anesthesia technique that aims to provide hip analgesia with preservation of motor function offering benefit over existing regional techniques while reducing overall opioid requirements.

DESIGN

A retrospective cohort chart review and analysis.

METHODS

A single-site, retrospective chart review was performed for individuals undergoing THAs at a community hospital from 2019 to 2022 (N = 123). Anesthesia records were collected and observed for multiple data points including peripheral nerve block provided, micrograms of fentanyl administered before and during the case, additional medications given, and additional nerve blocks performed. The demographic data included birth date, sex, and procedure date.

FINDINGS

For statistical analysis only, patients receiving PENG (59) were compared to those receiving only intravenous analgesia (No Block-57). Statistically and clinically significant reductions in fentanyl administration and morphine equivalents were found in the population receiving PENG blocks. The mean intraoperative fentanyl given to the No Block group was 292.98 mcg versus 50.42 mcg in the PENG group (P < .05). Mean morphine equivalents given in the No Block group was 23.51 mg versus 11.21 mg in the PENG group (P < .05).

CONCLUSIONS

Receiving a PENG block preoperatively resulted in clinically and statistically significant opioid reduction during the perioperative period when compared with patients who did not receive a regional block.

Midterm Comparative Analysis of Short Femoral Stem Survivorship in Dorr Type A Femurs

Background

Proximal-distal mismatch has emerged as a prominent concern in Dorr type A femoral morphology, prompting the exploration of short stems as promising alternatives to conventional stems. This study aimed to evaluate clinical and radiographic outcomes of total hip arthroplasty (THA) using short femoral stems in Dorr type A proximal femoral morphology with a minimum follow-up of 5 years.

Methods

Patients with short femoral stems in Dorr type A between 2011 and 2017 were included. Patients with the Short Modular Femoral (SMF) stem and Metha stem were recruited and patients with a shortened tapered stem (Tri-Lock BPS) were matched by propensity score matching based on age, sex, body mass index, calcar to canal ratio, and diagnosis. Patient-reported outcomes and the presence of thigh pain were assessed at 5 years postoperatively. Revision rate, complication rate, and radiographic outcomes were also assessed and compared.

Results

Twenty-two cases (81%) in the SMF stem and 43 cases (65%) in the Metha stem had more than 5 years of follow-up data available. The SMF stem showed a higher failure rate than the other 2 groups, with 18% requiring revision surgery in the SMF stem compared to 4.6% in the Metha stem, and 2.3% in the Tri-Lock BPS. The SMF stem showed considerable complications such as stem position change and lateral cortical hypertrophy with inferior clinical outcomes than the other 2 stem groups. When the Metha stem and the Tri-Lock BPS groups were compared, more intraoperative fractures were observed in the Metha stem, whereas stress shielding and anterior thigh pain were significantly more prevalent in the Tri-Lock BPS.

Conclusions

The SMF stem might be less reliable than previously reported, showing a high failure rate and increased radiologic complications. Thus, its use for THA in Dorr Type A femurs needs caution. On the other hand, the Metha stem showed comparable outcomes to the shortened tapered Tri-Lock BPS.

Routine pretransfusion testing before primary total hip or knee arthroplasty are an expensive and wasteful routine. Systematic review and meta-analysis

BACKGROUND

The excessive routine ordering of pretransfusion tests (blood typing, screening, and cross-matching) for surgical cases incurs significant unnecessary costs and places an undue burden on transfusion services. This study aims to systematically review the literature regarding the necessity of routine pretransfusion tests before total hip arthroplasty (THA) or total knee arthroplasty (TKA) and summarize their outcomes.

STUDY METHODS

A systematic review and meta-analysis were performed. The study's characteristics, the prevalence of over-ordering pretransfusion tests, transfusion rates, and potential cost savings to the healthcare system were analyzed.

RESULTS

The study included 17,667 patients. Pooled results revealed a 96.3% over-ordering pretransfusion test rate (95% CI: 0.92-1.00; p < 0.001) among patients undergoing primary THA or TKA. The pooled prevalence of hospital transfusion rate was 3.6%. Notably, there were statistically significant differences in preoperative hemoglobin (Hb) levels between patients not requiring transfusion (Hb = 13.9 g/dl; 95% CI 12.59-15.20; p < 0.001) and those needing transfusion (Hb = 11.9 g/dl; 95% CI 10.69-13.01; p < 0.001) (p = 0.03). The per-patient total cost savings ranged from 28.63 to 191.27 dollars.

DISCUSSION

Our study suggests that routine pre-transfusion testing for all patients undergoing primary THA or TKA may be unnecessary. We propose limiting pretransfusion test orders to patients with preoperative hemoglobin levels below 12 g/dl in unilateral primary TKA or THA. This targeted approach can result in significant cost savings for healthcare systems and transfusion services by reducing the over-ordering of pretransfusion tests in these surgical procedures.

THA-AID: Deep Learning Tool for Total Hip Arthroplasty Automatic Implant Detection With Uncertainty and Outlier Quantification

BACKGROUND

Revision total hip arthroplasty (THA) requires preoperatively identifying in situ implants, a time-consuming and sometimes unachievable task. Although deep learning (DL) tools have been attempted to automate this process, existing approaches are limited by classifying few femoral and zero acetabular components, only classify on anterior-posterior (AP) radiographs, and do not report prediction uncertainty or flag outlier data.

METHODS

This study introduces Total Hip Arhtroplasty Automated Implant Detector (THA-AID), a DL tool trained on 241,419 radiographs that identifies common designs of 20 femoral and 8 acetabular components from AP, lateral, or oblique views and reports prediction uncertainty using conformal prediction and outlier detection using a custom framework. We evaluated THA-AID using internal, external, and out-of-domain test sets and compared its performance with human experts.

RESULTS

THA-AID achieved internal test set accuracies of 98.9% for both femoral and acetabular components with no significant differences based on radiographic view. The femoral classifier also achieved 97.0% accuracy on the external test set. Adding conformal prediction increased true label prediction by 0.1% for acetabular and 0.7 to 0.9% for femoral components. More than 99% of out-of-domain and >89% of in-domain outlier data were correctly identified by THA-AID.

CONCLUSIONS

The THA-AID is an automated tool for implant identification from radiographs with exceptional performance on internal and external test sets and no decrement in performance based on radiographic view. Importantly, this is the first study in orthopedics to our knowledge including uncertainty quantification and outlier detection of a DL model.