Reasons for Revision: Primary Total Hip Arthroplasty Mechanisms of Failure

Unsuspected Positive Intra-Operative Cultures in Aseptic Revision Hip Arthroplasty: Prevalence, Management, and Infection-Free Survivorship

BACKGROUND

This study aimed to describe the management and outcomes of aseptic revision total hip arthroplasty (arTHA) with unsuspected intraoperative positive cultures (UPCs) compared to those with sterile cultures.

METHODS

A single tertiary center's institutional database was retrospectively reviewed for arTHA from January 2013 to October 2023. Preoperative Musculoskeletal Infection Society scores were assigned to patients based on available infectious workup, and those who met the criteria for periprosthetic joint infection (PJI), received antibiotic spacers, or had less than 1-year follow-up were excluded. Patients were grouped and compared according to intraoperative culture results as follows: sterile cultures, one unexpected positive culture with a new organism, one UPC with the same organism as prior PJI, ≥ two UPCs with different organisms, and ≥ 2 UPCs with the same organism.

RESULTS

There was a total of 604 arTHAs included in this study, of which 0.8% [5 of 604] had ≥ two UPCs with different organisms, 1.5% [9 of 604] had ≥ two UPCs with the same organism, 9.8% [59 of 604] had one UPC with a new organism, 0.2% [one of 604] had one UPC with an organism from prior PJI, and 87.7% [530 of 604] of patients had sterile cultures. When comparing 5-year infection-free survival between patients who had one UPC with a new organism and sterile cultures, there was no difference (P = 0.40); however, patients who had ≥ two UPCs with different organisms (P < 0.001), patients who had ≥ two UPCs with the same organism (P = 0.001), and patients who had one UPC of an organism from prior PJI (P < 0.001) had statistically worse infection-free survival compared to patients with sterile cultures.

CONCLUSIONS

Infection-free survival at five years was similar between patients who had one UPC with a new organism and those who had sterile cultures; however, ≥ two UPCs and a history of PJI are both significant risk factors for rerevision for infection after arTHA.

Dual-Mobility Articulations in Primary Total Hip Arthroplasty: Mid-Term Outcomes From the American Joint Replacement Registry

BACKGROUND

In recent years, there has been an increased utilization of dual-mobility (DM) implants in primary total hip arthroplasty (THA) to mitigate the risk of postoperative hip instability. This study aimed to present mid-term outcomes of DM bearings in primary THA using data from the American Joint Replacement Registry.

METHODS

Screening was conducted on patients aged ≥ 65 years who underwent primary THA between 2012 and 2018. Patients were categorized into three groups: (1) DM articulation, (2) ≤ 32-mm femoral head, and (3) ≥ 36-mm femoral head. Multivariable statistical modeling was employed to analyze patient and hospital characteristics, minimizing potential confounding variables and identifying independent associations with revision. Cox proportional hazards regression analyses were used to assess all-cause revision and revision specifically for instability. A total of 207,526 primary THAs were identified. Among them, 13,896 (6.7%) utilized DM articulation, 60,358 (29.1%) had a femoral head size of ≤ 32 mm, and 133,272 (64.2%) had a femoral head size of ≥ 36 mm.

RESULTS

At the 8-year follow-up, the all-cause revision rate was higher in the DM group (3.5%, 95% confidence interval [CI] 3.1 to 4.1) compared to the ≤ 32-mm (2.6%, 95% CI 2.5 to 2.8) and ≥ 36-mm (2.7%, 95% CI 2.5 to 2.9) groups. However, the revision rate for instability was comparable among the DM (0.4%, 95% CI 0.2 to 0.5), ≤ 32 mm (0.5%, 95% CI 0.4 to 0.5), and ≥ 36 mm (0.3%, 95% CI 0.3 to 0.4) groups at 8-year follow-up.

CONCLUSIONS

The utilization of DM was associated with higher overall revision rates. However, no significant differences in rates of revision for instability were observed among any of the bearing surface groups. These findings may be attributed to surgeons selectively utilizing DM articulations in higher-risk patients.

Nanosurgery and Bioengineered Regenerative Protocols for the Treatment of Hip Osteoarthritis: A Double-Blind Randomized Controlled Trial as an Alternative to Surgical Hip Replacement

Introduction: Hip osteoarthritis (HOA) significantly affects mobility and quality of life, with total hip arthroplasty (THA) being a common treatment. However, complications and increasing revision rates highlight the need for alternative approaches. This study evaluates the efficacy of ultrasound-guided nanosurgery and bioengineering treatment (NSBT) compared to non-standardized platelet-rich plasma (PRP) treatment for patients with symptomatic HOA. Methods: A double-blind, randomized trial included 38 patients referred for THA, divided into two groups. The study group received NSBT with modified PRP enriched with somatotropin and Strophanthus kombe, while the control group received PRP and hyaluronic acid injections without a standardized protocol. Treatments were guided by ultrasound, and outcomes were assessed using the Visual Analog Scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), Harris Hip Score (HHS), and range of motion (RoM) evaluations over 12 months. Results: The study group showed significant improvements in all clinical outcomes, including reductions in VAS scores from 7.8 to 0.2 (p < 0.0001) and WOMAC scores from 76.2 to 10.5 (p < 0.0001). The HHS improved from 56.4 to 93.0, and RoM showed substantial gains in flexion, external rotation, and internal rotation (all p < 0.001). The control group demonstrated less pronounced improvements. Conclusions: NSBT offers a safe and effective alternative for managing HOA, significantly reducing pain and improving joint function while potentially delaying or avoiding the need for THA. Further long-term studies are warranted to confirm these findings.

Evolving Patterns in Revision Total Hip Arthroplasty: Frequency, Complexity, and Indications over Two Decades at a High-Volume Tertiary Referral Center

INTRODUCTION

Patterns in revision total hip arthroplasty (THA) have continued to evolve throughout the decades. We investigated whether these trends could vary by practice location and analyzed the indications and incidence of revision and "complex" revision THA at our isolated regional academic referral center over the past two decades. We hypothesized that our regional referral center has attracted an increasing level of complexity in revision THA cases over time.

METHODS

A retrospective chart review was conducted on all revision THAs from 2000 to 2023. Indications and details of revision THA were recorded. Using previously published methods, cases were classified as "complex" if they included extended trochanteric osteotomy (ETO), triflange, augments, or a cup-cage construct. Trends in indications and complexity were compared between the periods 2000 to 2004 (early) and 2019 to 2023 (recent) using Chi-square tests.

RESULTS

A total of 2,793 revision THAs were performed from 2000 to 2023 (an average of 116 revisions/year). Comparing 2000 to 2004 with 2019 to 2023, the average annual number of revision THA increased from 89.8 to 157.6. The total volume of complex revisions was higher (average 13.2 cases/year historically versus 20.2 recent). Specifically, the annual averages of ETO increased from 6.8 to 9, augments from 0.8 to 4.2, triflange from 2.2 to 2.8, and cup-cage constructs from 5.4 to 5.8. Indications changed significantly over time, with more often loosening historically (39%) and infection/reimplantation more recently (35.9%) (P < 0.0001).

DISCUSSION

At a large regional academic referral center, we have seen a major increase in total numbers of revision THA cases with a concomitant increase in "complex" cases from 2000 to 2023. Indications for revision THA have transitioned from loosening historically to infection/reimplantation more recently.

Early Outcomes Following Total Hip Arthroplasty with a Newly Designed, Collared Triple Tapered Cementless Femoral Stem

BACKGROUND

Cementless femoral fixation in total hip arthroplasty (THA) is the most frequently utilized technique in the United States due to the efficacy of biologic fixation and reduced intraoperative times compared with cemented fixation, but has been associated with complications including periprosthetic fracture and loosening. A recently introduced collared triple-tapered cementless stem has been engineered to address and mitigate these adverse events, but its safety remains unproven. The purpose of this study was to report early complications and causes of failure of this stem and to report patient satisfaction and function.

METHODS

A retrospective review of patients who underwent primary THA using this device at a single institution from April 2022 to January 2024 was conducted. A total of 443 cases were performed that met the inclusion criteria. Patient demographics, including age, sex, American Society of Anesthesiologiest (ASA) score, and comorbidities, were collected. The primary outcome of interest was early complications (within 90 days) requiring readmission or revision surgical intervention. Patient-reported outcome measures (PROMs) such as the Veterans Rand 12 (VR-12) Item Health Survey (both physical and mental components), Hip Dysfunction and Osteoarthritis Outcome Score for Joint Replacement (HOOS, Jr.), and the Harris Hip Score (HHS) were also recorded and analyzed.

RESULTS

A total of six patients (1.4%) required reoperation or readmission following their THA. There was one Vancouver B2 periprosthetic fracture sustained after a fall at physical therapy (0.2%) and one acute periprosthetic infection (0.2%) that required reoperation. There were four patients who had medical issues requiring readmission (0.9%). There were no cases of dislocation or early loosening. Patients experienced significant improvements in their PROMs at both the six-week mark and at the final postoperative follow-up visit (P < 0.0001).

CONCLUSIONS

The recently introduced femoral stem appears to be a safe and effective implant option in the short-term postoperative period, resulting in low complication rates and high levels of patient satisfaction. Future longer-term follow-up studies are necessary to fully characterize its risk profile and effectiveness.

The effect of acetabular shell and liner design on posterior horizontal dislocation distance in modern dual-mobility implants

BACKGROUND

The posterior horizontal dislocation distance (PHDD) is a 3-dimensional jump distance measurement that is relevant to the risk of dislocation. There are a number of dual-mobility (DM) constructs with varying designs available. The present study identifies design factors associated with increased PHDD and evaluates the PHDD of 3 DM implants.

METHODS

3 different computer-aided implant designs were virtually implanted within a 3-dimensional CT-derived pelvic model. Each design represented an analogue of a DM system (MDM, OR3O, and G7) according to specific variations in acetabular liner rim build-up and femoral head centre location. The effective head diameters and PHDD values were calculated for each size acetabular shell and DM design.

RESULTS

The positive rim build-up design (MDM) showed higher PHDD values as compared to the other 2 hemispherical rim designs with no build-up, across all studied shell sizes. Specifically, the MDM design analogue had 16.4-29.0% greater PHDD values than the OR3O design analog and 15.2-30.5% greater PHDD values than the G7 design analogue The effect of a sfemoral head centre location relative to the liner head centre (OR3O) was negated by a larger effective head diameter to shell diameter ratio of the G7 design, resulting in similar PHDD values.

CONCLUSIONS

Design parameters affect the PHDD values of DM cups. The use of an elevated rim was associated with greater PHDD values. A medialised femoral head centre should also improve PHDD values, but the effect was nullified due to consecutive lower effective head diameters.

Use of Limited Femorotomy as an Alternative to Extensive Trochanteric Osteotomy for Cementless Femoral Prosthesis Revision

Background

Cementless stem extraction during hip arthroplasty revision can be challenging and sometimes requires a femoral opening to be performed with limited posterior femorotomy techniques been described. The study objective was to assess the efficacy of these techniques and the perioperative and postoperative complication rates.

Methods

This study included 224 patients who underwent cementless stem revision. Stem extraction followed the same sequence: an initial endomedullary extraction attempt, followed by suspended posterior unicortical vertical diaphyseal femoral osteotomy. Metaphyseal extension of the osteotomy and lateral-distal cortical extension at the stem tip were performed if the procedure failed, followed by extended trochanteric osteotomy (ETO). The incidence rates of perioperative fracture, reimplanted stem type (standard or revision), postoperative subsidence, and fracture were analyzed.

Results

Femoral opening was required in 15.6% of patients; 75% underwent limited femorotomy (28 patients, 75% suspended, and 25% extended), and 25% (7 patients) underwent ETO. Endomedullary extraction was performed in 84.4% (189) of the patients. The perioperative fracture rates were 16.9%, 0%, and 14.3% in the endomedullary, limited femorotomy, and ETO groups, respectively (P = .032). The standard stem utilization rates were 94.9%, 82.1%, 58.6%, and 28.6% (P < .001) for the endomedullary, limited femorotomy, perioperative fracture, and ETO groups, respectively. Postoperatively, the subsidence rates were 7.5%, 0%, and 28.6% (P = .042), and the fracture rates were 4.3%, 3.6%, and 0% (P > .999) in the endomedullary, limited osteotomy, and ETO groups, respectively.

Conclusions

Limited femorotomy techniques are reliable methods for extracting cementless stems, when necessary, with a reduced risk of fracture. Postoperatively, these patients appear to have comparable stem subsidence and a low risk of fracture.

Medical- and Implant-Related Complications Following Total Joint Arthroplasty in Patients Who Have Chronic Lymphocytic Leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) is highly prevalent in the total joint arthroplasty age group but has not been properly evaluated. This study aimed to assess the following: 1) 90-day medical complications, 2) implant-related complications, 3) healthcare utilization, and 4) time to revision in CLL and non-CLL total joint arthroplasty.

METHODS

The CLL cases undergoing total knee arthroplasty (TKA) and total hip arthroplasty (THA) were identified using diagnostic and procedural codes. The CLL TKA and THA patients were matched in a 1:5 ratio, with controls based on demographics and comorbidities. The outcomes included 90-day medical complications, 2-year implant complications, length of stay, 90-day readmission, and time to revision.

RESULTS

The CLL TKA patients had significantly higher odds of 90-day medical complications compared to controls, notably pneumonia (OR [odds ratio], 9.2; CI [confidence interval], 7.1 to 12.0; P < 0.001) and myocardial infarction (OR, 5.5; CI, 3.9 to 7.9; P < 0.001). Similarly, CLL THA patients had greater odds of 90-day medical complications, especially pneumonia (OR 10.0; CI 8.2 to 12.2; P < 0.001) and acute kidney injury (OR 6.3; CI 5.1 to 7.8; P < 0.001). The CLL TKA patients faced higher odds of periprosthetic fracture, mechanical loosening, and prosthetic joint infection, while THA patients had increased periprosthetic fractures. Revisions occurred earlier for THA than TKA (337 ± 547 versus 643 ± 774 days). The CLL patients had longer length of stay(TKA: 5.9 ± 6.5 versus 3.1 ± 1.6 days; P < 0.001) (THA: 6.3 ± 12.9 versus 3.0 ± 2.4; P < 0.001) and higher 90-day readmission rates (OR, 1.3; CI, 1.1 to 1.5, P < 0.001).

CONCLUSIONS

Orthopaedic surgeons should consider CLL status for informed patient counseling and complications mitigation.

Increasing Limb Length During Stage 1 Revision Leads to Higher Rates of Instability Following Stage 2 Revision Total Hip Arthroplasty

BACKGROUND

Currently, two-stage revision total hip arthroplasty is the gold standard in managing periprosthetic joint infection (PJI) of the hip; however, complications are common, including instability. The purpose of this study was to determine how alterations in limb length during a stage 1 articulating spacer affect dislocation rates of the stage 2 revision.

METHODS

A retrospective study of consecutive patients who underwent two-stage revision total hip arthroplasty for PJI between December 2013 and December 2022 was performed. We measured limb length as the perpendicular distance from the trans-teardrop line to the apex of the lesser trochanter after stage 1 articulating spacer implantation. Independent t-tests and logistic regression were used to compare limb lengths following stage 1 spacers between patients who did and did not dislocate after stage 2 implantation. Overall, 147 patients who underwent staged revisions for the treatment of PJI were identified. The cohort was 59% women who had a mean age of 60 years (range, 25 to 84 years) and an average follow-up time of 2.7 years (range, 1.0 to 9.1 years).

RESULTS

The dislocation rates after stage 1 and stage 2 were 3.0 and 11.7%, respectively. Limb length did not impact dislocation rates of the articulating stage 1 spacers (P = 0.71), but patients who sustained a dislocation following stage 2 were lengthened significantly more at stage 1 implantation (8.5 ± 15.9 versus 0.8 ± 11.8 mm, P = 0.033). Additionally, the odds of dislocation after stage 2 increased by 7% with each mm lengthened during stage 1 (odds ratio = 1.07, 95% confidence interval: 1.01 to 1.13).

CONCLUSIONS

During a stage 1 articulating spacer of the hip, limb length restoration is often disregarded, which can result in overlengthening that may necessitate subsequent shortening during stage 2 reconstruction. This study demonstrates that overlengthening of an articulating stage 1 hip spacer can place the patient at an increased risk of dislocation following stage 2 reconstruction.

Does Femoral Head Size Matter? A Comparison of 32-, 36-, and 40-Millimeter Heads in Primary Total Hip Arthroplasty: An American Joint Replacement Registry Analysis

BACKGROUND

Studies have shown that increased femoral head size reduces the risk of dislocation in primary total hip arthroplasty (THA), but there has been limited research on femoral head sizes greater than 36 mm.

METHODS

The American Joint Replacement Registry was utilized to evaluate all primary THA cases in Medicare patients aged 65 years and older who had a femoral head size of 32, 36, or ≥ 40 mm between 2012 and 2020. Patients who received a ≥ 40-mm head were more likely to be men and had a higher Charlson comorbidity index (CCI, P < 0.001). Multivariate analyses were performed to adjust for age, sex, race, femoral head composition, and CCI. Cox's proportional hazards models were used to compare differences in revision between groups.

RESULTS

Of 319,531 total THA cases, 84,524 (26.4%) used a 32 mm, 211,814 (66.3%) used a 36 mm, and 23,193 (7.3%) used ≥ 40-mm femoral head. When compared to 32-mm heads, 36-mm heads had significantly lower rates of revision for dislocation (32 mm: 0.68%, 36 mm: 0.46%, P < 0.001). Femoral heads ≥ 40 mm were not associated with a decreased rate of revision for dislocation (0.51%) when compared to 32 and 36 mm heads. However, femoral heads ≥ 40 mm were associated with an increased risk of all-cause revision (32 mm: 2.55%, 36 mm: 2.37%, 40 mm: 2.78%, P < 0.001) and revision for infection (32 mm: 0.43%, 36 mm: 0.53%, 40 mm: 0.82%, P < 0.001) compared to 32 and 36 mm heads.

CONCLUSIONS

Large femoral heads (≥ 40 mm) do not decrease revision for dislocation in primary THA but were associated with an increased risk of all-cause revision and revision for infection. Although demographic and comorbidity variables were controlled in our multivariate analysis, more men and higher CCI in ≥ 40-mm head patients may represent a population with a greater presurgical risk for complications. More research on ≥ 40-mm heads is warranted before widespread adoption.

Periprosthetic Joint Infection: Are Patients Still Better off Than if Primary Arthroplasty Had Not Been Performed?

BACKGROUND

This study sought to evaluate patient-reported outcome measures (PROMs) before primary total joint arthroplasty (TJA) and after successful treatment for periprosthetic joint infection (PJI), with the hypothesis that patients still demonstrate clinical improvement despite the occurrence of PJI.

METHODS

A single tertiary academic center's institutional database was retrospectively reviewed for patients who underwent primary TJA, developed PJI, and were managed for PJI from January 2019 to December 2023. Patients who did not have PROMs recorded were excluded from the study. Preoperative and postoperative generic and joint-specific PROMs were collected. Patient preprimary and postfinal revision surgery for PJI PROMs were subsequently compared. The minimum follow-up after PJI treatment was 6 months. A total of 55 patients (31 total knee arthroplasty and 24 total hip arthroplasty) were included with a mean follow-up of 1.8 years (range, 6 months to 4.5 years). All PJIs were managed via debridement, antibiotics, and implant retention, 1-stage, 1.5-stage, 2-stage revision, or resection arthroplasty.

RESULTS

After final revision surgery for PJI in total knee arthroplasty, patients had lower median patient-reported outcome measure information system (PROMIS) pain interference scores than before their primary surgery (62.0 [55.0, 67.0] versus 67.0 [65.0, 70.5]; P < 0.01). However, median PROMIS physical function postfinal revision for PJI and preprimary scores were similar (38.0 [33.0, 42.0] versus 34.0 [29.5, 40.0]; P = 0.08). After final revision surgery for PJI in total hip arthroplasty, patients had lower median PROMIS pain interference scores than before their primary surgery (57.5 [53.8, 64.0] versus 68.0 [66.5, 74.0]; P < 0.01). After final revision surgery for PJI, patients also had higher median PROMIS physical function scores than before their primary surgery (39.5 [33.5, 48.2] versus 29.5 [28.8, 34.2]; P < 0.01).

CONCLUSIONS

Patients who have been successfully managed for PJI show improvement in generic and joint-specific PROMs compared to their preprimary TJA PROMs.

Causes of Reoperations After Primary Total Hip Arthroplasty: A Retrospective Cohort Study Over 20 Years

BACKGROUND

Reoperations following total hip arthroplasty (THA) remain a major clinical challenge, with their incidence and socioeconomic burden rising despite advances in surgical techniques and prosthesis design. This study aimed to evaluate the predominant causes of reoperations following THA over two decades at a tertiary referral hospital, comparing trends between 2004 to 2013 and 2014 to 2023.

METHODS

We analyzed all reoperations performed at a tertiary referral hospital between January 2004 and December 2023. A total of 515 hips (483 patients) were included after excluding multiple reoperations on the same hip. The causes of reoperation were stratified into two time periods (2004 to 2013 and 2014 to 2023) to analyze trends. The time interval from primary THA to reoperations was also evaluated.

RESULTS

The main cause of reoperation after primary THA was aseptic loosening, accounting for 52.4% of cases, followed by infection (13.2%), periprosthetic fracture (PPF) (10.7%), wear/osteolysis (8.5%), ceramic fracture (5.8%), and instability/dislocation (5.6%). The proportion of aseptic loosening decreased significantly from 62.5 to 40.4%, while the proportions of infection, PPF, ceramic fracture, and instability/dislocation increased (P < 0.001). The causes of reoperation varied according to the time interval. Instability, PPF, and infection were early causes, and wear/osteolysis and aseptic loosening were relatively later causes of reoperations.

CONCLUSIONS

Aseptic loosening was the most common cause of reoperation following primary THA. However, the proportion of infection and PPF increased as a cause of reoperations, while the proportion of aseptic loosening decreased with time. Surgeons should consider that the main cause of reoperations differed according to the time interval from primary THA to reoperation.

Impact of CT-based navigation, large femoral head, and dual-mobility liner on achieving the required range of motion in total hip arthroplasty

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.

Methods

This retrospective study analyzed 60 manual and 51 CT-based navigated primary total hip arthroplasties performed at a single facility. Postoperative CT scans and CT-based simulation software were employed to measure the cup orientation and to simulate the ROM. We compared the absolute errors for radiological inclination (RI) and radiological anteversion (RA) between the two groups. We also examined whether the simulated ROM met the required ROM criteria, defined as flexion > 110°, internal rotation > 30°, extension > 30°, and external rotation > 30°. Furthermore, we performed simulations with 36 mm femoral head and dual-mobility liner.

Results

The absolute errors of RI and RA from the preoperative plan were significantly smaller in the CT-based navigation group (3.7° (SD 3.5°) vs 5.1° (SD 3.5°); p = 0.022, and 3.9° (SD 3.5°) vs 6.8° (SD 5.0°); p = 0.001, respectively). The proportion of cases achieving the required ROM in all directions was significantly higher in the CT-based navigation group (42% vs 63%; p = 0.036). The achievement rates of the required ROM were significantly higher with the use of a 36 mm ball or dual-mobility liner compared to the use of a 32 mm ball (65% vs 51%; p = 0.040 and 77% vs 51%; p ≤ 0.001, respectively).

Conclusion

CT-based navigation enhanced required ROM achievement rates by > 20%, regardless of the ball diameter. The improved accuracy of cup placement through CT-based navigation likely contributed to the enhancement. Furthermore, the use of large femoral heads and dual-mobility liners also improved the required ROM achievement rates. In cases with a high risk of dislocation, use of these devices is preferred.

Change in spinopelvic mobility 3 months after THA using a direct anterior approach

INTRODUCTION

Spinopelvic kinematics, reflected by the change in spinopelvic tilt (ΔSPT) from a standing position to a flexed seated position, has been associated with the risk of prosthetic impingement and hip dislocation. Some studies have suggested changes in spinopelvic mobility after total hip arthroplasty (THA), but none have explored changes in mobility in the first three months following THA using a direct anterior approach.

HYPOTHESIS

Our hypothesis was that changes in spinopelvic mobility occur in the first 3 months postoperatively, leading to increased hip mobility and increased spinopelvic kinematic abnormalities.

METHODS

This retrospective analysis of a consecutive series included 109 patients treated with primary anterior THA by a single senior surgeon. Lateral radiographs taken in standing and flexed seated positions before and three months after surgery were examined to analyze ΔSPT, pelvic femoral angle (PFA), lumbar lordosis (LL), and abnormal spinopelvic mobility (ΔSPT ≥20 °). Secondary objectives included examining the relationship between changes in lumbar flexion and hip flexion, and then analyzing preoperative spinopelvic parameters involved in postoperative pelvic mobility changes.

RESULTS

Between the two periods of analysis, the ΔSPT increased on average by 9.53 ° (-34.4/50.3 °), the ΔPFA increased by 7.68 ° (-74/49 °), and lumbar flexion (ΔLL) decreased by 4.26 ° (-20.8/26 °). The rate of ΔSPT ≥20 ° was 22.9% before the operation and 47.7% after the operation (OR = 8.98; CI [2.82; 28.56]; p < 0.001). A strong positive correlation was found between changes in ΔSPT and ΔPFA (ρ = 0.76; r2 = 0.574; p < 0.001) and no correlation between changes in ΔSPT and ΔLL (ρ=-0.019; r2 = 0.005; p = 0.842). The multivariate analysis demonstrated independent predictors of change in ΔSPT were body mass index (BMI, β = -0.59, [-1.15; -0.03], p = 0.0386), ΔPFA (β = -0.46, [-0.59; -0.34], p < 0.001), and ΔLL (β = -0.36, [-0.53; -0.19], p < 0.001). No dislocation was observed.

CONCLUSIONS

Spinopelvic mobility changes occur early on, within 3 months, after anterior THA. Patients with preoperative lumbar stiffness, associated with a stiff hip and lower BMI, should prompt surgeons to the risk of worsening spinopelvic kinematic abnormalities postoperatively.

LEVEL OF EVIDENCE

IV; retrospective study.

Outcomes of Direct Anterior Total Hip Arthroplasty in Patients Who Have Preoperative Gluteal Tendinopathy and Muscle Tears: A Propensity-Matched Analysis

BACKGROUND

The gluteus medius and minimus muscles play a critical role in hip biomechanics; however, there is a paucity of literature examining the impact of preoperative gluteal pathology on outcomes following total hip arthroplasty (THA). This study compared pain, satisfaction, and functional outcomes among patients who had and did not have preoperative gluteal pathology after direct anterior (DA) THA.

METHODS

Using an institutional total joint registry, patients undergoing DA THA for osteoarthritis between 2010 and 2022 were retrospectively reviewed. Those who had magnetic resonance imaging evidence of gluteal muscle tear or tendinopathy within one year before surgery were propensity-matched on a 1:4 basis by age, sex, body mass index, laterality, year of surgery, and surgeon to patients who had no clinical evidence of abductor pathology. There were 22 patients who had gluteal tears (eight of 22 men, age 63 ± 8.1 years) and 29 who had gluteal tendinopathy (nine of 29 men, age 60 ± 10.4 years) who were respectively matched to 88 and 116 controls and followed for 4.0 ± 2.3 (range, 1.1 to 12.7) years following DA THA. Postoperative outcomes were assessed using a visual analog scale (VAS) at rest, VAS with use, Hip Disability and Osteoarthritis Outcome Score pain, Forgotten Joint Score-12, and modified Harris Hip Score (mHHS). Subsequent injections and reoperations were recorded.

RESULTS

While all achieved excellent outcomes, patients who had gluteal muscle tears experienced less improvement in pain and function compared to controls, trending toward a lower final mHHS score (P = 0.052). Patients who had gluteal tendinopathy reported worse pain, satisfaction, and function than controls according to measures of VAS at rest (P = 0.014), VAS with use (P = 0.003), Hip Disability and Osteoarthritis Outcome Score pain (P = 0.005), Hip Disability and Osteoarthritis Outcome Score (P = 0.003), and mHHS (P = 0.007). Postoperative injections and subsequent hip surgeries were infrequent despite no intraoperative tendon treatment. Key limitations included limited sample size and lack of intraoperative data.

CONCLUSIONS

Patients who had gluteal pathology do well following DA THA; however, gluteal muscle tears and tendinopathies are associated with greater pain, decreased satisfaction, and inferior functional outcomes.

Robotic-assistance is associated with better joint outcomes compared to conventional techniques in surgically routine total hip arthroplasty: a propensity-matched large database study of 3948 patients

INTRODUCTION

The outcomes of total hip arthroplasty (THA) are highly dependent upon the restoration of native hip biomechanics and optimal component positioning. Robotic technologies for THA have rapidly improved the accuracy of component positioning and maintaining the planned center of rotation. While robotic-assisted THA (RA-THA) has primarily been employed in surgically intricate cases, its potential benefits in scenarios of diminished surgical complexity remain less explored. Therefore, the purpose of this study was to assess the odds of developing systemic and joint complications following RA-THA in cases of reduced surgical complexity.

METHODS

A retrospective cohort study was conducted using the TriNetX national database to identify patients who underwent primary THA (Current Procedural Terminology code 27,130) and more specifically RA-THA identified by ICD-10-PCS code 8E0Y0CZ and Healthcare Common Procedure Coding System code S2900 from 2013 to 2022. One-to-one propensity score matching was conducted to generate 2 cohorts: (1) RA-THA and (2) conventional THA (C-THA). Systemic and joint complications were assessed at the 30-day, 90-day, 1-year, and 5-year postoperative periods.

RESULTS

Patients undergoing RA-THA had a lower risk of needing a revision THA at the 90-day, 1-year, and 5-year time points. RA-THA was associated with a lower risk of prosthetic dislocation at 90 days and 1 year and prosthetic pain at 1 year and 5 years. Dislocation of the hip or fracture of the femur was significantly lower in the RA-THA cohort at all four-time points. Patients undergoing RA-THA had a lower risk of developing deep vein thrombosis at 5 years.

CONCLUSION

These findings suggest that RA-THA has comparable systemic and less joint complication risks at 30-day to 5-year timepoints between RA-THA and C-THA. Future studies with large sample sizes and long-term follow-up are needed to understand the patient-reported outcomes and functional outcomes of RA-THA for cases with reduced surgical complexity.

Impact of Flatback Deformity and Stiff Spinopelvic Mobility on 3-Dimensional Pelvic and Hip Kinematics After Total Hip Arthroplasty

Background

Spinopelvic abnormalities have been reported to be a risk factor for dislocation after total hip arthroplasty (THA). This study aimed to compare the kinematics of the pelvis and hip joints in patients with and without spinopelvic abnormalities after THA and to elucidate dynamic forward-leaning movement during chair-rising, which are not detectable through static radiographs.

Methods

This case series included 108 hips that underwent dynamic anteroposterior radiographic imaging of the sit-to-stand motion after THA. The average age at surgery was 68 ± 10 years, with 95 hips (88%) in women (average body mass index, 23.5 ± 3.2 kg/m2). Kinematic analysis was performed to measure the anterior pelvic plane angle (APPa) and hip flexion/extension angles from seated to standing positions using model-image registration techniques. Pelvic incidence (PI) and lumbar lordosis (LL) were measured to calculate PI-LL.

Results

Flatback deformity was present in 45 hips (42%) and stiff spinopelvic mobility (SPM) in 35 hips (32%), with both deformities present in 21 hips (19%). The pelvis was consistently significantly posteriorly tilted in the flatback deformity group throughout the movement compared with the normal group, with the greatest difference observed in the standing position. The hip flexion angles in the flatback deformity group showed significant extension in the standing position (7° greater than that in the normal group). For stiff SPM, a significant posterior tilt in the standing position was observed. Accordingly, the range between the maximum hip flexion and extension was 13° greater. There was no significant difference between the maximal flexion and extension centers.

Conclusions

Patients with flatback deformities consistently exhibited posterior APPa, especially when standing. In stiff SPM, a large range of hip flexion and extension while chair-rising increased the risk of impingement, indicating the necessity for a wider range of motion without changing the target orientation. These findings highlight the importance of considering spinopelvic alignment when planning cup positioning in THA to minimize the risk of dislocation.

Level of Evidence

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

A prospective multicentre study of 82 prosthetic joint infections treated with a standardised debridement and implant retention (DAIR) protocol followed by 6 weeks of antimicrobial therapy: favourable results

INTRODUCTION

Prosthetic joint infection (PJI) is a much-feared complication in total joint arthroplasty. Debridement, antibiotics, irrigation and implant retention (DAIR) is often the preferred treatment in acute PJIs, but with varying results. The primary aim of this study was to evaluate the outcome of a high quality DAIR procedure performed according to a consistently applied surgical protocol in early postoperative and acute haematogenous PJIs in hip and knee, and secondary to study risk factors associated with failure.

METHODS

We performed a prospective multicentre study to evaluate the effect of a standardised protocol-based surgical management (DAIR) emphasising a thorough debridement, followed by 6 weeks of antimicrobial therapy. Empiric parenteral antimicrobial treatment was administered until the results of susceptibility tests were available. No suppressive antimicrobial therapy was given after the 6-week treatment-period. Primary outcome measure was infection control at the 2-year follow-up.

RESULTS

A total of 99 patients from 8 Norwegian hospitals were found eligible and included in the study, and 82 patients were finally analysed. 69 of 82 patients (84% [CI, 76-92%]) were successfully treated with this treatment protocol. We found a reduced success rate when patients were treated with a DAIR procedure following an infected revision arthroplasty compared with an infected primary arthroplasty (11/17 (65 %) versus 58/65 (89 %), respectively (p = 0.02).

CONCLUSIONS

The success rate of a standardised DAIR procedure with a 6-week antimicrobial treatment was good in PJI following primary arthroplasties. The success rate following PJI in revision arthroplasty was poor, and other treatment options should be considered.

Synovial calprotectin in prosthetic joint infection. A systematic review and meta-analysis of the literature

INTRODUCTION

Calprotectin is a protein endowed with antimicrobial properties, rendering it a distinctive marker for infection. Two methods are currently available for the assay of calprotectin: the enzyme-linked immunosorbent assay (ELISA) and the lateral flow test (LFT). We aimed to assess the diagnostic accuracy of synovial fluid calprotectin and to compare the accuracy of the laboratory-based test and the qualitative assessment for the diagnosis of hip and knee prosthetic infection.

MATERIALS AND METHODS

We searched (from inception to November 2023) MEDLINE, Scopus, EMBASE, Web of Science, and Cochrane for studies on calprotectin in the diagnosis of periprosthetic joint infection (PJI). Sensitivity, specificity, positive and negative likelihood ratio (LR), and diagnostic odds ratio were analyzed. The receiver-operating curve for each method was calculated.

RESULTS

We included 14 articles in our meta-analysis, including 902 patients who underwent total hip and knee arthroplasties revision; 331 (37%) had a joint infection according to MSIS, MSIS-modified criteria, ICM 2018 and EBJIS 2021. Considering the false-positive result rate of 6% and false-negative result rate of 7%, pooled sensitivity and specificity were 0.92 (95% CI 0.89-0.94) and 0.93 (0.91-0.95), respectively. The area under the curve (AUC) was 0.93 (95% CI 0.91-0.94). No statistical differences in terms of sensitivity and specificity were found between ELISA and LFT. The pooled sensitivity and specificity of the two calprotectin assessment methods were: LFT 0.90 (95% CI 0.869-0.935) and 0.92 (95% CI 0.894-0.941), respectively; ELISA 0.96 (95% CI 0.914-0.986) and 0.97 (95% CI 0.934-0.988), respectively. The diagnostic odds ratio of the ELISA was superior to that of the LFT (906.6667, 95% CI 271.2686-3030.3712 versus 113.8886, 95% CI 70.4001-184.2414; p < 0.001). The AUC for ELISA and LFT was 0.968 (95% CI 0.944-0.984) and 0.915 (95% CI 0.895-0.933), respectively.

CONCLUSIONS

Detection of synovial calprotectin is an accurate test for diagnosis of hip and knee prosthetic infections. The diagnostic accuracy of the two calprotectin assessment methods is almost comparable. The LFT is a valid, rapid, and more available diagnostic tool, particularly to rule out PJI.

Management of hip osteoarthritis: harnessing the potential of mesenchymal stem cells-a systematic review

INTRODUCTION

Hip osteoarthritis (OA) is a prevalent and debilitating condition, necessitating effective and safe treatment options. This systematic review aims to explore the potential of intra-articular mesenchymal stem cell (MSC) infiltrations as a therapeutic approach for hip OA.

METHODS

Following PRISMA guidelines, a systematic review was conducted, encompassing PubMed, Embase, and Cochrane Library databases. Inclusion criteria involved studies focusing on intra-articular MSC injections in patients with hip OA and reporting pain relief as an outcome measure. Quality assessment utilized the Newcastle-Ottawa scale and methodological index for non-randomized studies.

RESULTS

Ten studies were included in the review, exhibiting varied designs and sample sizes (316 patients). Outcome measures consisted of cartilage repair assessed through MRI and radiographies, pain scores (WOMAC, VAS, NRS), and functional improvements (HOS-ADL, OHS, FRI, PDQQ, LEFS). The studies reported favorable improvements in functional scores, pain relief, and cartilage repair/radiographic findings, with minimal reported adverse events.

CONCLUSIONS

Intra-articular MSC infiltrations demonstrate promise as an effective and safe therapeutic intervention for managing hip OA, offering pain relief and functional enhancements. Nevertheless, limited high-quality studies and outcome measure variations underscore the need for further research to establish definitive treatment guidelines. Future investigations should address optimal MSC utilization, long-term outcomes, and potential complications to ensure the success of MSC-based therapies for hip OA management, ultimately improving patient outcomes. The findings provide valuable insights into the potential of MSC-based treatments for hip OA, advocating further rigorous research in this field.

TRIAL REGISTRATION

The protocol was registered on PROSPERO database (CRD42023436973).

The Epidemiology of the Revision Total Hip Arthroplasty in the United States From 2016 to 2022

Background

The number of revision total hip arthroplasties (THAs) is projected to reach 572,000 cases annually by 2030 in the United States. This may be attributed to the successes of primary THAs combined with an aging population, patients desire to remain active, and expanded indications for younger patients. Given the evolving nature of revision THAs, an epidemiological analysis of (1) etiologies; (2) demographics, including age and region; and (3) lengths of stay (LOSs) may minimize the gap between appropriate understanding and effective intervention.

Methods

From 2016 to 2022, a national, all-payer database was queried. Incidences and indications were analyzed for a total of 102,476 patients who had revision THA procedures. Patients were stratified according to etiology of failure, age, US census region, primary payor class, and mean LOS.

Results

The most common etiologies for revision THA procedures were dislocation (16.7%) and infection (12.7%), followed by periprosthetic fracture (6.9%). The largest age group was 65-74 years (30.9%), followed by >75 years (28.6%), then 55-64 (26.5%). The South had the largest total procedure cohort (36.9%), followed by the Midwest (27.5%), then the Northeast (19.7%), and the West (15.9%). The mean LOS was 4.10 days (range, 1.0-20.0).

Conclusions

Dislocation and infection remain leading indications for revision THA. These findings can properly guide surgeons toward appropriate management as well as toward active steps to minimizing these outcomes.

Systematisation of the causes that required revision hip replacement, methods of their solution, treatment results in Ukraine

BACKGROUND

The objective of this study is to organise data on complications following total hip replacement (THA) over a span of 10 years, specifically focussing on cases that necessitated revision endoprosthetic surgeries. The objective is to create a recommendation for an All-Ukrainian registry of initial and repeated hip arthroplasty (HA) and standardise the terminology used to define "revision of total hip replacement surgery".

METHODS

The retrospective analysis examined 236 instances of revision hip arthroplasty (rTHA) performed at the Institute of Traumatology and Orthopaedics Centre between January 2005 and December 2021. The primary factors for revision were identified through an analysis of the patient's medical records, laboratory results, visual inspection, and the state of the previously implanted prosthesis. Demographic information, primary and revision HA dates, diagnoses, and causes of complications were recorded. The statistical analysis was conducted using the Statistica package (StatSoft), version 12.6 (2015), with a significance level of p < 0.05.

RESULTS

Out of the 364 patients who were diagnosed with complications, 236 of them (55.17%) needed a procedure called 1rTHA. Among these cases, 152 (41.76%) were specifically diagnosed with aseptic component instability. Significant factors for mechanical loosening were a high body mass index (BMI ≥ 30) and older age, with respective t-values of 2.08 (p = 0.004) and 2.59 (p = 0.045). Osteoporosis significantly contributed to aseptic loosening and fractures around the implant. The occurrence of infectious complications was frequently linked to chronic infectious diseases (t = 3.37, p = 0.001). The overall percentage of need for 2rTHA was 27.22% (43 cases), with one case of infectious lesion following the revision.

CONCLUSIONS

The study emphasises the urgent requirement for standardised terminology and a comprehensive registry for hip arthroplasty procedures. Primary results indicate that cement-free fixation is more effective than cement-based fixation for revision in patients with aseptic instability and that two-stage arthroplasty is effective for treating infectious inflammation. Furthermore, the most effective treatment for femoral fractures with periprosthetic involvement was determined to be open repositioning and osteosynthesis with metal retainers. The aforementioned observations emphasise the need to create a comprehensive registry across Ukraine to support patient care, enable evidence-based practices, and enhance the overall effectiveness of hip arthroplasty operations.

CLINICAL TRIAL NUMBER

Not applicable.

Prediction of intraoperative press-fit stability of the acetabular cup in total hip arthroplasty using radiomics-based machine learning models

BACKGROUND

Preoperative prediction of the acetabular cup press-fit stability in total hip arthroplasty is necessary for clinical decision-making. This study aims to establish and validate machine learning models to investigate the feasibility of predicting the intraoperative press-fit stability of the acetabular cup in total hip arthroplasty (THA).

METHODS

226 patients who underwent primary THA from 2018 to 2022 in our hospital were retrospectively enrolled. Patients were divided into press-fit stable or unstable groups according to the intraoperative pull-out test of the implanted cup. Then, they were randomly assigned to the training or test cohort in an 8:2 ratio. We used 3Dslicer software to segment the region of interest (ROI) of the patient's bilateral hip X-ray to extract radiomics features. The least absolute shrinkage and selection operator (LASSO) regression was used in our feature selection. Finally, four machine learning models were employed in this study, including support vector machine (SVM), random forest (RF), logistic regression (LR), and XGBoost (XGB). Decision curve analysis (DCA), and receiver operating characteristic (ROC) curves of the models were plotted. The area under the curve (AUC), diagnostic accuracy, sensitivity, and specificity were calculated as well. The AUCs of the four models were compared using the DeLong test.

RESULTS

Twenty-seven valuable radiomics features were determined by dimensionality reduction and selection. Regarding to the DeLong test, the AUC of the XGB model was significantly different from those of the other three models. (p < 0.05). Among all models, the XGB model exhibited the best performance with an AUC of 0.823 (95 % CI: 0.711-0.919) in the test cohort and showed optimal clinical efficacy according to the DCA.

CONCLUSION

Machine learning models based on X-ray radiomics can accurately predict the intraoperative press-fit stability of implanted cups preoperatively, providing surgeons with valuable information to lower the complication risk in THA.

Should All Patients Receive Extended Oral Antibiotic Prophylaxis? Defining Its Role in Patients Undergoing Primary and Aseptic Revision Total Joint Arthroplasty

BACKGROUND

Prior studies have demonstrated reduced periprosthetic joint infection (PJI) rates following extended oral antibiotics (EOAs) for high-risk patients undergoing primary total joint arthroplasty (TJA). This study compared 3-month PJI rates in all patients undergoing primary or aseptic revision TJA with or without EOA prophylaxis.

METHODS

In total, 2,982 consecutive primary (n = 2,677) and aseptic revision (n = 305) TJAs were performed by a single, fellowship-trained arthroplasty surgeon from 2016 to 2022 were retrospectively reviewed. Beginning January 2020, all patients received 7 days of 300 mg oral cefdinir twice daily immediately postoperatively. Rates of PJI at 3 months were compared between patients who received or did not receive EOA.

RESULTS

Rates of PJI at 3 months in patients undergoing primary and aseptic revision TJA were significantly lower in those receiving EOA prophylaxis compared to those who did not (0.41 versus 1.13%, respectively; P = .02). After primary TJA, lower PJI rates were observed with EOA prophylaxis utilization (0.23 versus 0.74%, P = .04; odds ratio [OR] 3.85). Following aseptic revision TJA, PJI rates trended toward a significant decrease with the EOA compared to without (1.88 versus 4.83%, respectively; P = .16; OR 2.71).

CONCLUSIONS

All patients undergoing primary or aseptic revision TJA who received EOA prophylaxis were 3.85 and 2.71 times less likely, respectively, to develop PJI at 3 months compared to those without EOA. Future studies are needed to determine if these results are maintained at postoperative time periods beyond 3 months following primary TJA.

LEVEL OF EVIDENCE

III, Retrospective review.

Intrawound Vancomycin Powder in Primary Total Hip Arthroplasty: A Prospective Quality Control Study

BACKGROUND

The purpose of this retrospective analysis of a prospective quality control project was to determine whether the use of intrawound vancomycin powder (IVP) decreases the rate of periprosthetic joint infection (PJI) within 90 days following primary total hip arthroplasty (THA).

METHODS

From October 2021 to September 2022, a prospective quality control project was undertaken in which 10 high-volume THA surgeons alternated between using and not using IVP each month while keeping other perioperative protocols unchanged. A retrospective analysis of the project was performed to compare the group of patients who received IVP to the group of patients who did not. The primary outcome was a culture positive infection within 90 days following primary THA. Secondary outcomes included gram-positive culture, overall reoperation rate, wound complications, readmission, and wound complications within 90 days post-operatively. A total of 1,193 primary THA patients were identified for analysis. There were 523 (43.8%) patients who received IVP and were included in the IVP group, while 670 (56.2%) did not and were included in the non-IVP group. Age, body mass index, and sex were similar between the 2 groups (P > .25).

RESULTS

The IVP group had a higher rate of culture positive joint infections (1.7 [0.8, 3.2] versus 0.3% [0.04, 1.1], P = .01) than the non-IVP group. All PJI's were found to have gram positive bacteria in both groups. The IVP group had a higher overall reoperation rate than the non-IVP group (6.1 [4.2, 8.5] versus 2.4% [1.4, 3.9], P < .01). The IVP group had a higher reoperation rate for any wound complication compared to non-IVP patients (2.7 [1.5, 4.5] versus 0.7% [0.2, 1.7], P < .01). The overall readmission rate (6.1 [4.2, 8.5] versus 2.8% [1.7, 4.4], P < .01), as well as readmission for suspected infection (2.1 [1.1, 3.7] versus 0.6% [0.02, 1.5], P = .03), were higher in the IVP group.

CONCLUSIONS

The use of IVP in primary THA was associated with a higher rate of PJI, overall reoperation, reoperation for wound complications, and readmission in a prospective quality control project. Until future prospective randomized studies determine the safety and efficacy of IVP in THA conclusively, we advocate against its utilization.

The CCJR® Charles A. Engh, Sr, MD. Excellence in Hip Research Award: The Evolution of Revision Hip Arthroplasty and Impact on the Trainee's Experience

BACKGROUND

Advances in total hip arthroplasty (THA) have resulted in evolving revision indications and intraoperative techniques, which can influence the exposure of trainees to complex cases. We report 3 decades of revision experience from a tertiary referral center that trains fellows, comparing the reasons for revision and the complexity of revisions over time.

METHODS

We retrospectively reviewed all revision THAs performed at our institution from 1990 to 2022. Revision diagnoses, components revised, types of revision implants used, and exposure techniques were collected. A "complex" revision was defined as a case that involved an extended trochanteric osteotomy, triflange and cup-cage construct, or acetabular augment.

RESULTS

A total of 3,556 THA revisions were identified (108 revisions/year). Aseptic loosening was the most common indication in 1990 to 1999 (45 per year), but decreased to 28.3/year in 2010 to 2019. From 1990 to 1999 and 2010 to 2019, fracture increased from 3.1 to 7.3 per year, infection from 2.9/year to 16.9/year, and metallosis from 0.1 to 13.2 per year. Both component revision were common from 1990 to 1994 (42.6 per year), while polyethylene exchange was most common in 2010 to 2019 (43.3 per year). A decrease was observed in "complex" cases over time: 14.8 extended trochanteric osteotomies/year in 2000 to 2004 compared to 5.4 per year in 2018 to 2022, 4.5 triflange and cup-cage constructs/year in 2004 to 2007 compared to 0.8 per year in 2018 to 2022, and 4 acetabular augments per year in 2009 to 2012 compared to 1 per year in 2018 to 2022.

CONCLUSIONS

Indications for revision have changed over the decades, while the number of "complex" revisions has gradually decreased, presumably due to advances in implants and materials. If this trend extends to other training institutions, the next generation of arthroplasty surgeons will have less exposure to complex revisions during their training.

3D preoperative predictions of in vivo hip stability and edge loading for neutral and lipped liners

Hip dislocation is one of the leading causes of failure and revision surgery for total hip arthroplasty. To reduce dislocation rates, lipped liners have been designed with an elevated portion of the rim, to increase jump distance and maintain greater contact area. While it has been documented that lipped liners help reduce dislocation, the objective of this study is to investigate whether lipped liners also help reduce smaller instances of hip micromotion, separation, and edge loading. This study uses an advanced three-dimensional preoperative planning tool to analyze 10 patients, each implanted with both a neutral and lipped liner. Patients within the simulation performed stance phase of gait, and each cup was implanted with the rotation center aligned with the preoperative acetabulum center as well as shifted medially by 2, 4, 6, 8, and 10 mm, yielding 120 total simulations. Specific postoperative outcomes-of-interest included specified component offset, resultant in vivo hip forces, hip separation, and contact area to evaluate edge loading. The planner predicted a reduction in hip separation and an increase in articulating contact area for when using a lipped liner compared to a neutral liner. Additionally, regardless of liner type, increases in hip separation corresponded to decreases in contact area, therefore resulting in edge loading of the liner. Together, this indicates that improper component alignment and offsets may lead to an increase in hip separation and edge loading, but the use of a lipped liner may provide improved stability and resistance to this micromotion.

Body Mass Index Does Not Drive the Risk for Early Postoperative Instability After Total Hip Arthroplasty: A Matched Cohort Analysis

BACKGROUND

Instability remains the leading cause of revision following total hip arthroplasty (THA). The objective of the present investigation was to determine whether an elevated body mass index (BMI) is associated with an increased risk of instability after primary THA.

METHODS

An administrative claims database was queried for patients undergoing elective, primary THA for osteoarthritis between 2010 and 2022. Patients who underwent THA for a femoral neck fracture were excluded. Patients who had an elevated BMI were grouped into the following cohorts: 25 to 29.9 (n = 2,313), 30 to 34.9 (n = 2,230), 35 to 39.9 (n = 1,852), 40 to 44.9 (n = 1,450), 45 to 49.9 (n = 752), and 50 to 59.9 (n = 334). Patients were matched 1:1 based on age, sex, and Elixhauser Comorbidity Index, as well as a history of spinal fusion, neurodegenerative disorders, and alcohol abuse, to controls with a normal BMI (20 to 24.9). A multivariate logistic regression controlling for age, sex, Elixhauser Comorbidity Index, and additional risk factors for dislocation was used to evaluate dislocation rates at 30 days, 90 days, 6 months, 1 year, and 2 years. Rates of revision for instability were similarly compared at 1 year and 2 years postoperatively.

RESULTS

No significant differences in dislocation rate were observed between control patients and each of the evaluated BMI classes at all evaluated postoperative intervals (all P values > .05). Similarly, the risk of revision for instability was comparable between the normal weight cohort and each evaluated BMI class at 1 year and 2 years postoperatively (all P values > .05).

CONCLUSIONS

Controlling for comorbidities and known risk factors for instability, the present analysis demonstrated no difference in rates of dislocation or revision for instability between normal-weight patients and those in higher BMI classes.

Contemporary Isolated Bearing Exchange for the Management of Hip Instability Following Primary Total Hip Arthroplasty

BACKGROUND

Isolated ball and liner exchanges (IBLEs) can be performed to increase hip joint stability, but historical results have been mixed due to a lack of head size options or dual mobility articulations. The purpose of this study was to evaluate the contemporary results of IBLEs in patients who have instability following primary total hip arthroplasty (THA).

METHODS

We retrospectively reviewed 65 primary THAs from 2016 to 2020 with hip instability undergoing IBLE or conversion to dual mobility articulation. There were 31 men and 34 women who had an average age of 70 years (range, 26 to 92). The mean time to revision from primary was 40.1 months (range, 1 to 120). In 52 cases, IBLE was performed using conventional bearings, while 13 hips were converted to dual mobility. Radiographic factors, including acetabular component orientation, reproduction of hip joint offset, leg lengths, and outcomes such as recurrent instability requiring subsequent revision and patient-reported outcome measure, were recorded and compared.

RESULTS

There were 12 (18.4%) hips that experienced subsequent instability and required another revision (17.3% ball and liner exchange versus 23.1% dual mobility articulation, P = .615). The mean time to rerevision for instability was 17.1 months. There were no significant differences in either acetabular component anteversion (P = .25) or restoration of hip joint offset (P = .87) in patients who required another revision for instability compared to those who did not, respectively. At 1 year, patients undergoing conventional bearing exchange reported higher Hip Dysfunction Osteoarthritis Outcome Score for Joint Replacements (P = .002) and Veterans Rand physical component (P = .023) scores compared to those who underwent a conversion to dual mobility articulation. Only age > 75 years at the time of surgery was associated with increased risk for dislocation (odds ratio 7.2, confidence interval 1.2 to 43.7, P = .032).

CONCLUSIONS

Isolated bearing exchanges for instability following THA remained at high risk for subsequent instability. Conversion to dual mobility articulations did not reduce the risk of reoperation.

Usage of Tranexamic Acid for Total Hip Arthroplasty: A Matched Cohort Analysis of 144,344 Patients

Background: The literature is inconclusive regarding the potential complications of tranexamic acid (TXA), an antifibrinolytic drug, for total hip arthroplasty (THA). The purpose of this study is to compare complication rates and patient outcomes between THA patients administered TXA vs. THA patients not administered TXA. Methods: The TriNetX Research network was utilized to generate a cohort of adult patients who underwent THA between 2003 and 2024. These patients were categorized into two subgroups for the retrospective analysis: (1) patients who received TXA 24 h prior to THA (TXA), and (2) patients who did not receive TXA 24 h prior to total hip arthroplasty (no-TXA). The follow-up period was 30 and 90 days. Results: At 30 days following THA, the TXA patients had a reduced risk of transfusion (risk ratio (RR): 0.412; 95% confidence intervals (CI): 0.374, 0.453), reduced risk of DVT (RR: 0.856; CI: 0.768, 0.953), reduced risk of joint infection (RR: 0.808; CI: 0.710, 0.920), but a higher rate of periprosthetic fracture (RR: 1.234; CI: 1.065, 1.429) compared to patients who did not receive TXA. At 90 days following THA, TXA patients had a reduced risk of transfusion (RR: 0.446; CI: 0.408, 0.487), DVT (RR: 0.847; CI: 0.776, 0.924), and periprosthetic joint infection (RR: 0.894; CI: 0.815, 0.982) compared to patients who did not receive TXA. Patients who received TXA had higher rates of periprosthetic fracture (RR: 1.219; CI: 1.088, 1.365), acute postoperative anemia (RR: 1.222; CI: 1.171, 1.276), deep surgical site infection (SSI) (RR: 1.706; CI: 1.117, 2.605), and superficial SSI (RR: 1.950; CI: 1.567, 2.428) compared to patients who did not receive TXA. Conclusions: Patients receiving TXA prior to THA exhibited significantly reduced the prevalence of blood transfusions, DVT, and periprosthetic joint infection following THA. However, superficial SSI and periprosthetic fracture were seen with higher rates in the TXA cohort than in the no-TXA cohort.

Monte Carlo-based in-depth morphological analysis of medullary cavity for designing personalized femoral stem

Background

The design of femoral stem prostheses requires a precise understanding of the femoral marrow cavity. Traditional measurements of morphological parameters in the upper femur, particularly the medullary cavity and cortical region, are primarily based on coronal and sagittal axes, which may not fully capture the true three-dimensional structure of the femur.

Methods

Propose a Monte Carlo-based method for a more comprehensive analysis of the femoral marrow cavity, using CT scans of femurs from a selected group of patients. The study aimed to define and calculate anatomically semantic morphological parameters to enhance the understanding of the femoral marrow cavity's anatomical morphological changes, ultimately improving the design and clinical selection of femoral stem prostheses. To enhance the accuracy of femoral stem prosthesis design, this study aims to develop a Monte Carlo-based method for a more comprehensive analysis of the femoral marrow cavity. The proposed method transforms the non-random problem of determining cross-sectional size into a random issue, allowing for the calculation of the size of the medullary cavity and cortical region. Anatomically semantic morphological parameters are then defined, calculated, and analyzed.

Results

The experimental results indicate that the newly defined parameters complement existing ones, providing a more rational scientific basis for understanding the anatomical morphological changes of the femoral marrow cavity.

Conclusion

This research offers essential scientific theoretical support for improved morphologic research, design, and clinical selection of femoral stem prostheses. It holds significant importance and application value in clinical practice, contributing to a more accurate and comprehensive understanding of femoral anatomy for prosthetic design.

Robotic Arm-Assisted System Improved Accuracy of Cup Position and Orientation in Cementless Total Hip Arthroplasty for Dysplastic Hips: A Comparison Among Groups With Manual Placement, Computed Tomography-Based Navigation, and Robotic Surgery

Background

Accurate cup placement in total hip arthroplasty (THA) for patients with dysplasia is challenging due to the distinctive bone deformities. This study aimed to compare the accuracy of cup placement position and orientation across robotic arm-assisted systems (R-THA), computed tomography-based navigation (N-THA), and manual procedure (M-THA) in THA for osteoarthritis secondary to dysplasia.

Methods

A total of 167 patients (197 hips), including 88 R-THAs, 45 N-THAs, and 46 M-THAs, were analyzed. Propensity score matching was performed to align the patient backgrounds. Horizontal and vertical centers of rotation were measured for cup position, whereas radiographic inclination and anteversion were measured for cup orientation. The proportion of cases with cup placement within 3 mm and 5° from the target was compared.

Results

R-THA had a significantly higher percentage of cup placement within 3 mm of the target compared to N-THA (78% vs 49%; P = .0041) and M-THA (78% vs 53%; P = .013). Similarly, R-THA was significantly more successful in placing the cup within 5° of the target compared to N-THA (84% vs 58%; P = .0049) and M-THA (91% vs 20%; P < .0001). Moreover, N-THA was significantly better at placing the cup within 5° of the target compared to M-THA (62% vs 14%; P < .0001), whereas there was no significant difference in the percentage of cup placement within 3 mm of the target (51% vs 51%; P = 1.0).

Conclusions

Robotic arm-assisted system and computed tomography-based navigation improved accuracy in cup orientation compared to the manual procedure. Additionally, the robotic arm-assisted system further improved cup position accuracy.

A new approach to identify wear regions on bearing surfaces of retrieved endoprostheses

Although total hip replacements (THR) can be considered one of the most successful implantable medical devices in history, wear remains the ultimate challenge in order to further increase clinical success. Wear assessment on retrieved implants is the most reliable way to perform research into failure mechanisms. Therefor the bearing surface of the explant is measured geometrically by coordinate measuring machine (CMM). Wear determination in geometrical data is carried out in 3 steps: (1) identifying the worn area, (2) reconstructing the pre-wear geometry and (3) quantify wear as the difference between worn area and pre-wear geometry. In previous studies, assumptions to pre-wear geometry had been made for wear determination (step 2) and the worn area was identified by deviations between measured data and assumed form. Thus, the original form of the retrieved endoprostheses, including form deviations due to the manufacturing process and implantation, was not considered which leads to uncertainties in the wear computed. This work introduces a method which allows to identify the wear area without making assumptions to the original form. Instead, the curvature of the bearing surface obtained by simple computations on the measurement data is analysed and the edge of the wear region is recognized by its deviation in curvature. The method is applied to a retrieved Metal-on-Metal prosthetic head and the results are compared to those of the well-known method introduced by Jaeger et al., in 2013. With the new approach the wear region is identified more accurately.

Total hip arthroplasty for fractured neck of femur does not restore preoperative hip-specific function, health-related quality of life, or level of fitness

PURPOSE

The primary aim was to assess whether a total hip arthroplasty (THA) was able to restore health-related quality of life (HRQoL) following an intracapsular hip fracture. The secondary aims were to assess changes in hip-specific function, fitness/frailty, mortality risk, complications and revision risk, and factors independently associated with these.

METHODS

This retrospective cohort study included all patients aged ≥ 50 years admitted with a hip fracture from the emergency department at a single centre during a 42-month period. Patient demographics, perioperative variables, complications, revision, and mortality were collected. Patient-reported outcome measures (PROMs) were assessed at final follow-up.

RESULTS

Among 250 identified patients, 189 (75.6%) were women with a mean age of 70.3 (range 50-94 years). Mean follow-up was 2.3 (SD 1.1) years. The implant and patient survival rates at 2 years were both 95.5% (95% confidence intervals (CI) +/- 2.7). Older age (hazard ratio [HR] 1.22, 95% CI 1.12-1.33, p < 0.001) and male sex (HR 3.33, 95% CI 1.15-10.0, p = 0.026) were independently associated with mortality. There were 19 (7.6%) postoperative complications that included 6 (2.4%) periprosthetic fractures, 5 (2.0%) deep infections, and 8 (3.2%) dislocations, of which 13 underwent revision. Increasing time to theatre (HR 1.02, 95% CI 1.01-1.03, p = 0.017) was independently associated with a postoperative complication. Postoperative PROMs were available for 166 (66.4%) patients. There were significant (p < 0.001) deteriorations in EuroQol-5D (Mean difference [MD] 0.192, 95% CI 0.133-0.252), Oxford hip score (MD 2.5, 95% CI 1.5-3.6), and fitness (Rockwood score MD 0.7, 95% CI 0.5-0.8) relative to preoperative levels of function.

CONCLUSION

THA may be the treatment of choice in a physically active patient with the aim of restoring their HRQoL, hip function, and fitness, but this was not observed. Furthermore, there was a high complication rate which was associated with increasing time to theatre.

LEVEL OF EVIDENCE

III, retrospective cohort study.

Bone graft incorporation failure with inappropriate limb load transfer can lead to aseptic acetabular loosening of metal-on-metal prosthesis: A case report

BACKGROUND

Aseptic acetabular loosening can result from various factors that can be categorized into groups: patient-related, surgeon-related and implant-related. We present a case of a 63-year-old patient who at first underwent a total hip arthroplasty (THA) using a metal-on-metal bearing due to hip arthrosis. Follow-up visits revealed no complications after the procedure. Two years after the THA, acetabular component loosening occurred due to subsequent trauma of the opposite hip, necessitating a revision THA using a ceramic-on-ceramic bearing.

CASE SUMMARY

We aim to illustrate a rare case where the primary reason for undergoing THA revision was not only incomplete bone graft incorporation but also improper limb load distribution. Following the revision arthroplasty, a 9-year follow-up visit revealed improvements in all evaluation measures on questionnaire compared to the state before surgery: Harris Hip Score (before surgery: 15; after surgery: 95), Western Ontario and McMaster Universities Arthritis Index (before surgery: 96; after surgery: 0), and Visual Analogue Scale (before surgery: 10; after surgery: 1).

CONCLUSION

Opposite-hip trauma caused a weight transfer to the limb after a THA procedure. This process led to a stress shielding effect, resulting in acetabular component loosening.

Detection of Total Hip Replacement Loosening Based on Structure-Borne Sound: Influence of the Position of the Sensor on the Hip Stem

Accurate detection of implant loosening is crucial for early intervention in total hip replacements, but current imaging methods lack sensitivity and specificity. Vibration methods, already successful in dentistry, represent a promising approach. In order to detect loosening of the total hip replacement, excitation and measurement should be performed intracorporeally to minimize the influence of soft tissue on damping of the signals. However, only implants with a single sensor intracorporeally integrated into the implant for detecting vibrations have been presented in the literature. Considering different mode shapes, the sensor's position on the implant is assumed to influence the signals. In the work at hand, the influence of the position of the sensor on the recording of the vibrations on the implant was investigated. For this purpose, a simplified test setup was created with a titanium rod implanted in a cylinder of artificial cancellous bone. Mechanical stimulation via an exciter attached to the rod was recorded by three accelerometers at varying positions along the titanium rod. Three states of peri-implant loosening within the bone stock were simulated by extracting the bone material around the titanium rod, and different markers were analyzed to distinguish between these states of loosening. In addition, a modal analysis was performed using the finite element method to analyze the mode shapes. Distinct differences in the signals recorded by the acceleration sensors within defects highlight the influence of sensor position on mode detection and natural frequencies. Thus, using multiple sensors could be advantageous in accurately detecting all modes and determining the implant loosening state more precisely.

Nanoparticle ultrasonication outperforms conventional irrigation solutions in eradicating Staphylococcus aureus biofilm from titanium surfaces: an in vitro study

PURPOSE

Bacterial biofilms create a challenge in the treatment of prosthetic joint infection (PJI), and failure to eradicate biofilms is often implicated in the high rates of recurrence. In this study, we aimed to compare the effectiveness of a novel nanoparticle ultrasonication technology on Staphylococcus aureus biofilm eradication compared to commonly used orthopedic irrigation solutions.

METHODS

Twenty-four sterile, titanium alloy discs were inoculated with a standardized concentration of methicillin-resistant S. aureus and cultured for seven days to allow for biofilm formation. Discs were then treated with either ultrasonicated nanoparticle therapy or irrigation with chlorhexidine gluconate, povidone-iodine or normal saline. The remaining bacteria on each surface was subsequently plated for colony-forming units of S. aureus. Bacterial eradication was reported as a decrease in CFUs relative to the control group. Mann-Whitney U tests were used to compare between groups.

RESULTS

Treatment with ultrasonicated nanoparticles resulted in a significant mean decrease in CFUs of 99.3% compared to controls (p < 0.0001). Irrigation with povidone-iodine also resulted in a significant 77.5% reduction in CFUs compared to controls (p < 0.0001). Comparisons between ultrasonicated nanoparticles and povidone-iodine demonstrated a significantly higher reduction in bacterial CFUs in the nanoparticle group (p < 0.0001).

CONCLUSION

Ultrasonicated nanoparticle were superior to commonly used bactericidal irrigation solutions in the eradication of S. aureus from a titanium surface. Future clinical studies are warranted to evaluate this ultrsonication technology in the treatment of PJI.

Effect of Patient Age on Total Hip Arthroplasty Outcomes in Patients Who Have Osteonecrosis of the Femoral Head Compared to Patients Who Have Hip Osteoarthritis

BACKGROUND

Osteonecrosis of the femoral head (ONFH) affects both young and old patients. However, outcomes following total hip arthroplasty (THA) for these patients may vary with age. This study aimed to examine the effect of age on THA outcomes for non-traumatic ONFH patients, an area currently lacking research.

METHODS

Patients who had non-traumatic ONFH undergoing THA with at least 2 years of follow-up were identified using a database and divided into four groups by age. Then, 4 matched control groups of patients who had hip osteoarthritis (OA) were created. Multivariate logistic regression analyses were used to evaluate the rates of medical and surgical complications. Additionally, cohorts with a minimum 5-year follow-up were filtered to obtain further data on surgical outcomes. The study analyzed 85,462 non-traumatic ONFH and 80,120 hip OA patients undergoing THA.

RESULTS

Multiple medical complications in ONFH patients increased with age. Periprosthetic fracture within 2 years increased with age, while 90-day wound complications, 2-year periprosthetic joint infections, dislocations, and revisions decreased. The trends for complications continued at the 5-year follow-up. Compared to OA patients, those who had ONFH had higher risks of most complications, but this discrepancy decreased with age.

CONCLUSIONS

In ONFH patients undergoing THA, medical complications generally rise with age, while most surgical complications, including revisions, decrease. It is notable that ONFH patients experienced more complications than those who had OA, but this difference diminished with age.

Early Radiographic and Clinical Outcomes of an Additive-Manufactured Acetabular Component

Background

Additive manufacturing has recently gained popularity and is widely adopted in the orthopaedic industry. However, there is a paucity of literature on the radiographic and clinical outcomes of these relatively novel components. The aim of this study was to assess the 2-year clinical and radiographic outcomes of a specific additive-manufactured acetabular component in primary total hip arthroplasty.

Methods

We performed a retrospective review of 60 patients who underwent primary total hip arthroplasty with the use of the Stryker's TRIDENT II acetabular component. Evaluation of radiographs was performed at 6 weeks, 1 year, and 2 years postoperatively. Radiographs were evaluated for radiolucencies in Charnley and DeLee zones, signs of biologic fixation, and acetabular inclination and anteversion measurements. Patient-reported outcomes and complications were also obtained.

Results

There were no cases of component loosening or changes in component position during follow-up, with an average follow-up time of 1.7 years. A radiolucent line was identified in one patient in zone 1 at 6 weeks; this was absent at 1 year. Radiographic signs of cup biologic fixation were present in 85% of cases by final follow-up. The average inclination was 45.1 (SD = 4.0), and the average anteversion was 26.9 (SD = 5.2). Patient-Reported Outcomes Measurement Information System scores significantly increased at the final follow-up, and there were no complications in this cohort.

Conclusions

This study demonstrated excellent radiographic and clinical outcomes with this novel additive-manufactured acetabular component at early follow-up. Although longer-term follow-up is warranted, this additively manufactured highly porous titanium acetabular component demonstrated excellent biologic fixation and reliable fixation at mid-term follow-up.

Robotic-assisted Total Hip Arthroplasty and Spinopelvic Parameters: A Review

Total hip arthroplasty (THA) is an effective treatment for osteoarthritis, and the popularity of the direct anterior approach has increased due to more rapid recovery and increased stability. Instability, commonly caused by component malposition, remains a significant concern. The dynamic relationship between the pelvis and lumbar spine, deemed spinopelvic motion, is considered an important factor in stability. Various parameters are used in evaluating spinopelvic motion. Understanding spinopelvic motion is critical, and executing a precise plan for positioning the implant can be difficult with manual instrumentation. Robotic and/or navigation systems have been developed in the effort to enhance THA outcomes and for implementing spinopelvic parameters. These systems can be classified into three categories: X-ray/fluoroscopy-based, imageless, and computed tomography (CT)-based. Each system has advantages and limitations. When using CT-based systems, preoperative CT scans are used to assist with preoperative planning and intraoperative execution, providing feedback on implant position and restoration of hip biomechanics within a functional safe zone developed according to each patient's specific spinopelvic parameters. Several studies have demonstrated the accuracy and reproducibility of robotic systems with regard to implant positioning and leg length discrepancy. Some studies have reported better radiographic and clinical outcomes with use of robotic-assisted THA. However, clinical outcomes comparable to those for manual THA have also been reported. Robotic systems offer advantages in terms of accuracy, precision, and potentially reduced rates of dislocation. Additional research, including conduct of randomized controlled trials, will be required in order to evaluate the long-term outcomes and cost-effectiveness of robotic-assisted THA.

Coxa valga and antetorta configuration leads to underestimation of the femoral component size: a matched case-control study of patients undergoing cementless total hip arthroplasty

BACKGROUND

Total hip arthroplasty (THA) is the gold standard procedure for patients with end-stage osteoarthritis after failed conservative therapy. Digital templating is commonly employed in preoperative preparation for THA and contributes positively to its outcome. However, the impact of coxa valga and antetorta (CVA) configurations on stem size prediction accuracy remains not reported. Previous studies demonstrated that the size of the lesser trochanter (LT) can be used to determine femoral anteversion on pelvis radiographs. This study investigates the accuracy of preoperative digital templating in predicting stem size in patients with CVA undergoing cementless THA.

METHODS

Preoperative radiographs of 620 patients undergoing cementless THA were retrospectively investigated. Radiographs were standardized with patients standing and the leg internally rotated by 15°. A CVA group was established including patients with a CCD angle greater than 140° and a lesser trochanter (LT) size of at least 10 mm for men and 8 mm for women. For the control group, radiographs with a CCD angle ranging from 125-135° and LT size 3-10 mm for men and 3-8 mm for women were selected. Preoperative templating was performed using mediCAD. To reduce confounding factors, case-control matching was carried out for BMI and body height.

RESULTS

After case-control matching, a total of thirty-one matches were analyzed. Stem size was underestimated in 74% (23/31) in the CVA and 13% (4/31) in the control group (p < 0.001). Moreover, patients with CVA were more likely to be underestimated by two sizes compared to controls (p < 0.004). In contrast, the exact stem size was predicted more frequently in the control group (p < 0.001).

CONCLUSION

Stem size in patients with a CVA configuration are at high risk of being underestimated when using digital templating. These findings can be valuable for guiding in intraoperative decisions and lowering the risk of complications associated with an undersized femoral component.

Use of Computer Navigation for Optimal Acetabular Cup Placement in Revision Total Hip Arthroplasty: Case Reports and Surgical Techniques

Background

The outcomes of revision total hip arthroplasty (rTHA) have become increasingly important as their volume increases. Computer navigation, a reliable method to improve component positioning during primary total hip arthroplasty (THA), is not well studied in the rTHA setting. Given that dislocation rates following rTHA are significantly higher than those of primary THA, component positioning becomes paramount in these cases.

Methods

Here, we present two case reports and surgical techniques, one of a 77-year-old man undergoing rTHA for recurrent hip instability following primary THA, and one of a 61-year-old woman undergoing rTHA for severe iliopsoas bursitis who was at increased risk for instability and dislocation given her history of large segment spinal fusion.

Results

Both patients achieved optimal acetabular component positioning after rTHA with imageless computer navigation.

Conclusions

The use of imageless computer navigation in rTHA provides accurate and reproducible component positioning during acetabular rTHA.

Re-revision and mortality rate following revision total hip arthroplasty for infection

Aims

This study compares the re-revision rate and mortality following septic and aseptic revision hip arthroplasty (rTHA) in registry data, and compares the outcomes to previously reported data.

Methods

This is an observational cohort study using data from the German Arthroplasty Registry (EPRD). A total of 17,842 rTHAs were included, and the rates and cumulative incidence of hip re-revision and mortality following septic and aseptic rTHA were analyzed with seven-year follow-up. The Kaplan-Meier estimates were used to determine the re-revision rate and cumulative probability of mortality following rTHA.

Results

The re-revision rate within one year after septic rTHA was 30%, and after seven years was 34%. The cumulative mortality within the first year after septic rTHA was 14%, and within seven years was 40%. After multiple previous hip revisions, the re-revision rate rose to over 40% in septic rTHA. The first six months were identified as the most critical period for the re-revision for septic rTHA.

Conclusion

The risk re-revision and reinfection after septic rTHA was almost four times higher, as recorded in the ERPD, when compared to previous meta-analysis. We conclude that it is currently not possible to assume the data from single studies and meta-analysis reflects the outcomes in the 'real world'. Data presented in meta-analyses and from specialist single-centre studies do not reflect the generality of outcomes as recorded in the ERPD. The highest re-revision rates and mortality are seen in the first six months postoperatively. The optimization of perioperative care through the development of a network of high-volume specialist hospitals is likely to lead to improved outcomes for patients undergoing rTHA, especially if associated with infection.

3-D finite element model of the impaction of a press-fitted femoral stem under various biomechanical environments

BACKGROUND

Uncemented femoral stem insertion into the bone is achieved by applying successive impacts on an inserter tool called "ancillary". Impact analysis has shown to be a promising technique to monitor the implant insertion and to improve its primary stability.

METHOD

This study aims to provide a better understanding of the dynamic phenomena occurring between the hammer, the ancillary, the implant and the bone during femoral stem insertion, to validate the use of impact analyses for implant insertion monitoring. A dynamic 3-D finite element model of the femoral stem insertion via an impaction protocol is proposed. The influence of the trabecular bone Young's modulus (Et), the interference fit (IF), the friction coefficient at the bone-implant interface (μ) and the impact velocity (v0) on the implant insertion and on the impact force signal is evaluated.

RESULTS

For all configurations, a decrease of the time difference between the two first peaks of the impact force signal is observed throughout the femoral stem insertion, up to a threshold value of 0.23 ms. The number of impacts required to reach this value depends on Et, v0 and IF and varies between 3 and 8 for the set of parameters considered herein. The bone-implant contact ratio reached after ten impacts varies between 60% and 98%, increases as a function of v0 and decreases as a function of IF, μ and Et.

CONCLUSION

This study confirms the potential of an impact analyses-based method to monitor implant insertion and to retrieve bone-implant contact properties.

Frailty Among Revision Total Knee Arthroplasty Recipients: Epidemiology and Propensity Score-weighted Analysis of Effect on In-hospital Postoperative Outcomes

BACKGROUND

Frailty has been shown to correlate with worse outcomes after total knee arthroplasty (TKA), although less is known regarding its effect on revision TKA (rTKA). This study examines the epidemiologic characteristics and inpatient outcomes of patients with frailty undergoing rTKA.

METHODS

Discharge data from National Inpatient Sample registry were used to identify all patients aged 50 years or older who underwent rTKA between 2006 and 2015. Patients were stratified into frail and nonfrail groupings, based on the presence of specific International Classification of Diseases-9 diagnostic coding. An analysis comparing the epidemiology, medical comorbidities, and propensity score-weighted postoperative clinical and economic outcomes of the two groups was done.

RESULTS

From 2006 to the third quarter of 2015, a total of 576,920 patients (17,727 frail) who underwent rTKA were included. The average age in the study's population was 67.2 years, with a female distribution of 57.4%. Frail patients were more likely to exhibit markedly higher rates of almost all modified Elixhauser Comorbities than their nonfrail counterparts. Frail patients were also more likely to undergo different types of revisions, including an increased rate of removal of the prosthesis without replacement. In addition, frail patients displayed increased likelihood of experiencing any postoperative complication, deep vein thrombosis, postoperative anemia, respiratory complications, and wound dehiscence. Frail patients experienced lower rates of discharge home and increased length of stay than the nonfrail cohort.

DISCUSSION

Patients with frailty undergoing rTKA are at markedly higher risk for inpatient postoperative complications and increased length of stay. Understanding the implications of frailty within rTKA is essential for risk assessment and preoperative optimization for this expanding population.

Dislocation Following Anterior and Posterior Total Hip Arthroplasty in the Setting of Spinal Deformity and Stiffness: Evolving Trends Using a High-Risk Protocol at a Single Tertiary Center

BACKGROUND

Patients who have spinal stiffness and deformity are at the highest risk for dislocation after total hip arthroplasty (THA). Previous reports of this cohort are limited to antero-lateral and postero-lateral (PL) approaches. We investigated the dislocation rate after direct anterior (DA) and PL approach THA with a contemporary high-risk protocol to optimize stability.

METHODS

We investigated patients undergoing THA who had preoperative biplanar imaging from January-December 2019. Patients were identified using radiographic criteria of spinal-stiffness (<10-degree change in sacral slope from standing to seated) and deformity (flatback deformity with >10-degree difference in pelvic incidence and lumbar lordosis). There were 367 patients identified (181 DA, 186 PL). The primary outcome was dislocation rate at 2-years postoperatively. Risk-factors for dislocation were evaluated using logistic regressions (significance level of 0.05).

RESULTS

There were 6 (1.6%) dislocations in the entire cohort, with low dislocation rates for both DA (0.6%) and PL-THA (2.7%). We observed increased utilization of dual mobility with larger outer head bearings (>38 mm) with PL-THA (34.4 versus 5.0%, P < .01) and conversely increased utilization of 32-mm femoral-heads with DA-THA (39.4 versus 7.0%, P < .001). Surgical approach (PL) was not a significant risk-factor for dislocation (odds ratio: 5.03, P = .15). Patients who had a history of lumbar-fusion had 8-times higher odds for dislocation (OR: 8.20, P = .020).

CONCLUSIONS

To the best of our knowledge, this is the largest series to date evaluating DA and PL-THA in the hip-spine 2B-group. Our results demonstrate lower dislocation rate than expected with either surgical approach using a high-risk protocol.

Aseptic Acetabular Revisions ≤90 Days, 91 Days to 2 Years, and >2 Years After Total Hip Arthroplasty: Comparing Etiologies, Complications, and Postoperative Outcomes

BACKGROUND

Isolated acetabular component revision is an effective treatment for revision total hip arthroplasty patients who have well-fixed femoral implants. We aimed to evaluate the modes of acetabular failure following primary total hip arthroplasty and to identify factors associated with increased morbidities and postoperative outcomes.

METHODS

We conducted a retrospective analysis and identified 318 isolated aseptic acetabular revisions. We separated patients by ≤90 days, 91 days to 2 years, and >2 years for acetabular revisions and compared demographics, reasons for revision, 90-day readmissions, rerevisions, and postrevision infections. Revisions ≤90 days, 91 days to 2 years, and >2 years accounted for 10.7, 19.2, and 70.1% of revisions, respectively. Revisions ≤90 days, 91 days to 2 years, and >2 years had their primary total hip arthroplasty at a mean age of 66, 63, and 55 years (P < .001), respectively.

RESULTS

Revisions within 90 days were mainly indicated for dislocation/instability (58.8%) or periprosthetic fracture (23.5%) while revisions over 2 years were indicated for polyethylene wear/osteolysis (37.2%). Patients with revisions past 90 days were more likely to require rerevision compared to patients with revisions within 90 days (P < .001). There were no differences in readmissions (P = .28) or infection rates (P = .37).

CONCLUSIONS

Acetabular revisions within 90 days were more commonly indicated for instability and periprosthetic fracture, while those over 2 years were indicated for polyethylene wear. Revisions past 90 days were more likely to require subsequent rerevisions without increased 90-day readmissions or infections.

LEVEL III EVIDENCE

Retrospective cohort study.

Permissive Weight Bearing in Patients With Surgically Treated Periprosthetic Femoral Fractures Around Total Hip Arthroplasty: A Scoping Review

Periprosthetic femoral fractures (PPFF) around total hip arthroplasty (THA) are one of the leading causes of hip revision. High mortality rates are observed after revision in case of PPFF around THA. To modify risk factors, early postoperative mobilization is necessary. Permissive weight bearing (PWB) is designed to optimize clinical recovery in aftercare. This study aimed to perform a scoping review to summarize the current available evidence on postoperative weight bearing in late PPFF around THA and the implementation of PWB in aftercare. A systematic search was performed on the Cochrane Library, Web of Science, Ovid MEDLINE, EMBASE, and CINAHL databases on January 26th, 2023. Articles were screened in two stages by two independent reviewers. Studies describing adult patients with a history of primary THA who were surgically treated for late PPFF and mentioning prescribed postoperative weight-bearing protocols with relevant outcome measures were included. Seven studies were included, reporting data on 22 patients (age range 47-97 years, BMI range 19-32 kg/m2, ASA classification range 2-3). No studies used PWB in aftercare. The non-weight-bearing group showed no complications. The restricted weight-bearing group had one death and one implant failure. The full weight-bearing group experienced one deep infection and one plate removal because of impingement. The main finding was that, after an extensive systematic search, no articles could be included focusing on PWB in patients with a late PPFF after THA. Addressing this gap in the literature is essential to advancing the understanding of postoperative weight-bearing protocols and PWB for late PPFF around THA.

Long-term survival and complication rate of cementless prosthetic stems in primary total hip arthroplasty categorized by types according to Mont classification: a regional registry-based study on 53,626 implants

INTRODUCTION

The purpose of this retrospective registry-based study is to assess survival and causes of failure of cementless stem implants used in total hip arthroplasty (THAs), to ascertain if there are differences when these are categorized according to the six types described by Mont.

METHODS

Data collected from the regional registry regarding all primary THAs performed from 2000 to 2019 were analyzed. Femoral prosthetic stems were divided into the six types of Mont classification. For each stem type, number of implants, survival and causes of failure were evaluated and compared.

RESULTS

The most frequently implanted stem type was the 3c type (53.4%). Type 1 had the lowest stem failure rate (1.6%), and type 6 showed the highest (3.9%). Periprosthetic fracture was the most frequent complication in type 6, accounting for 34.5% of failures. Aseptic loosening was the main complication in type 2 stems, accounting for 36.4% of failures. Pairwise comparisons showed significant higher survival of type 1 compared to type 3c (p = 0.000026) and type 6 (p = 0.000076), and between type 3a compared to type 3c (p = 0.03) and type 6 (p = 0.026).

CONCLUSION

Significant variations in implant survival rates were found among the six Mont-types of cementless stems. These findings emphasize the paramount importance of stem design and fixation area in determining long-term survival, providing a guidance for orthopedic surgeons in the selection of the most appropriate stem for primary THA, contributing to our understanding of cementless stem performance, presenting invaluable insights to further improve patient outcomes in THA surgery.

Comparison of Outcomes in High Versus Low Activity Level Patients After Total Joint Arthroplasty

BACKGROUND

Activity level (AL) recommendations following total joint arthroplasty (TJA) remain controversial. Our purpose was to compare implant survivorship of high activity (HA) and low activity (LA) patients after primary TJA. We hypothesized that there would be no difference in implant survivorship based on AL.

METHODS

This was a retrospective 1:1 matched cohort study after primary TJA with minimum 5-year follow-up. High activity patients were designated by the University of California and Los Angeles activity-level rating scale score ≥8 and matched to LA patients based on age (±5), sex, and body mass index (±5). There were 396 HA patients (149 knees and 48 hips) who met inclusion criteria. We analyzed revision rates, adverse events, and radiographic lucencies.

RESULTS

Crepitus was the most common adverse events in both HA and LA total knee arthroplasties (TKAs). Adverse events were rare in total hip arthroplasty (THA) cohorts. For both THA and TKA patients, the HA cohort did not have increased reoperations or revisions when compared to the LA cohort. No differences were noted in overall radiographic analysis between HA (16.1%) and LA (12.1%) TKA patients (P = .318), and in THA patients, more radiographic problems were noted in LA (P = .004).

CONCLUSION

We found no difference in minimum 5-year postoperative implant survivorship based on AL. This may change AL recommendations after TKA and THA.