Intraoperative estimation of natural femoral anteversion from proximal femoral osseous orientation during total hip arthroplasty.

BACKGROUND: The purpose of this study was to elucidate the relationship between the orientation of the osseous structure of the proximal femur encountered during total hip arthroplasty (THA) and preoperative femoral anteversion (FA). METHODS: Three-dimensional models were constructed using full-length lower extremity computed tomography images from a total of 80 participants. Femoral neck cutting was performed at heights of 5, 10, and 15 mm relative to the lesser trochanter. Following neck cutting, the angles formed by the anterior outer cortex and posterior outer cortex with the posterior condylar line (PCL) were defined as the anterior cortical angle (ACA) and posterior cortical angle (PCA), respectively. Univariate linear regression analysis was conducted using the remaining measurements with FA as the dependent variable. RESULTS: The mean age of the participants was 60.98 ± 10.82 years (males, 60.50 ± 11.36 years; females, 61.45 ± 10.37 years) (p = 0.697). All cortical angles and FA were larger in women compared to those in men. When comparing measurements by age groups, no statistically significant differences were observed. Univariate linear regression analysis with FA as the dependent variable showed statistical significance for all cortical angles. The adjusted R2 values were 0.711 (ACA5), 0.677 (ACA10), 0.572 (ACA15), 0.493 (PCA5), 0.574 (PCA10), and 0.446 (PCA15). CONCLUSION: Natural FA can be inferred from the anterior cortical angle (ACA) from femoral neck cutting plane observed during the THA procedure without preoperative images. TRIAL REGISTRATION: Retrospectively registered.

[AI-HIP system for prosthesis size, global femoral offset and osteotomy in total hip arthroplasty].

OBJECTIVE: To explore planning effect of AI-HIP assisted surgical planning system in primary unilateral total hip arthroplasty (THA) and its influence on clinical outcomes. METHODS: A retrospective analysis was conducted on clinical data of 36 patients who underwent their first unilateral THA from March 2022 to November 2022 and continuously used AI-HIP system (AI-HIP group), including 16 males and 20 females, aged from 43 to 81 years old with an average of (62.2±10.9) years old. According to the matching principle, 36 patients who were planned by the traditional template method at the same period were selected as the control group, including 16 males and 20 females, aged from 40 to 80 years old with an average of (60.9±12.1) years old. The accuracy between two groups of prostheses were compared, as well as the combined eccentricity difference between preoperative planning and postoperative practice, lower limb length difference, osteotomy height from the upper edge of the lesser trochanter and top shoulder distance to evaluate planning effect. Harris score and visual analogue scale (VAS) were used to evaluate clinical efficacy. RESULTS: Both groups were followed up for 12 to 18 months with an average of (14.5±2.1) months. The complete accuracy and approximate accuracy of acetabular cup and femoral stalk prosthesis in AI-HIP group were 72.2%, 100%, 58.3%, 88.9%, respectively, which were better than 44.4%, 83.3%, 33.3%, 66.7% in control group (P<0.05). There was no statistical significance in planning of femoral head prosthesis size (P>0.05). The actual combined eccentricity difference and combined eccentricity difference (practical-planning) in AI-HIP group were 1.0(0.2, 2.4) mm and 1.1(-2.1, 3.2) mm, respectively;which were better than 3.0 (1.4, 4.9) mm and 3.5 (-1.6, 6.5) mm in control group (P<0.05). There was no significant difference between two groups in actual osteotomy height of the upper margin of the lesser trochanter (P>0.05). In AI-HIP group, the actual difference of lower extremity length after surgery, the difference of lower extremity length (practical-planning), osteotomy height from the upper margin of lesser trochanter (practical-planning), actual topshoulder distance after surgery, and topshoulder distance (practical-planning) were 1.5 (0.2, 2.8), 1.1 (-0.3, 2.2), 2.1(-2.3, 4.1), (15.3±4.1), 2.2(-4.8, 0.3) mm, respectively;which were better than control group of 2.6(1.3, 4.1), 2.5 (0.3, 3.8), 5.8(-2.4, 7.7), (13.0±4.3), -5.7(-9.4, -2.2) mm(P<0.05). At final follow-up, there were no significant differences in Harris scores of pain, function, deformity, total scores and VAS between two groups (P>0.05). The range of motion score was 4.8±0.6 in AI-HIP group, which was higher than that in control group (4.4±0.8)(P<0.05). CONCLUSION: Compared with traditional template planning, AI-HIP assisted surgical planning system has good accuracy in predicting the prosthetic size of the acetabular cup and femoral stalk, restoring joint eccentricity, planning lower limb length, osteotomy height and top shoulder distance on the first unilateral THA, and the clinical follow-up effect is satisfactory.

Predicting extended hospital stay following revision total hip arthroplasty: a machine learning model analysis based on the ACS-NSQIP database.

INTRODUCTION: Prolonged length of stay (LOS) following revision total hip arthroplasty (THA) can lead to increased healthcare costs, higher rates of readmission, and lower patient satisfaction. In this study, we investigated the predictive power of machine learning (ML) models for prolonged LOS after revision THA using patient data from a national-scale patient repository. MATERIALS AND METHODS: We identified 11,737 revision THA cases from the American College of Surgeons National Surgical Quality Improvement Program database from 2013 to 2020. Prolonged LOS was defined as exceeding the 75th value of all LOSs in the study cohort. We developed four ML models: artificial neural network (ANN), random forest, histogram-based gradient boosting, and k-nearest neighbor, to predict prolonged LOS after revision THA. Each model's performance was assessed during training and testing sessions in terms of discrimination, calibration, and clinical utility. RESULTS: The ANN model was the most accurate with an AUC of 0.82, calibration slope of 0.90, calibration intercept of 0.02, and Brier score of 0.140 during testing, indicating the model's competency in distinguishing patients subject to prolonged LOS with minimal prediction error. All models showed clinical utility by producing net benefits in the decision curve analyses. The most significant predictors of prolonged LOS were preoperative blood tests (hematocrit, platelet count, and leukocyte count), preoperative transfusion, operation time, indications for revision THA (infection), and age. CONCLUSIONS: Our study demonstrated that the ML model accurately predicted prolonged LOS after revision THA. The results highlighted the importance of the indications for revision surgery in determining the risk of prolonged LOS. With the model's aid, clinicians can stratify individual patients based on key factors, improve care coordination and discharge planning for those at risk of prolonged LOS, and increase cost efficiency.

Acetabular revision for iliopsoas impingement: a study of 55 cases at 3 years of follow-up. Does the procedure achieve the Minimal Clinically Important Difference (MCID) in the Oxford-12 score in more than 80% of cases?

INTRODUCTION: Several surgical options can be offered to manage iliopsoas impingement. Research published on cup replacements often concerns a small population size or multicentre studies, suggesting a variety of indications. We conducted a retrospective single centre study screening according to a specific protocol of a population of patients who had a cup replacement for iliopsoas impingement. The objectives were: 1) to specify the functional outcomes and the achievement of the Minimal Clinically Important Difference (MCID) and the Patient Acceptable Symptom State (PASS) according to the Oxford-12 score, and 2) to assess the complication rate. HYPOTHESIS: Our hypothesis was that acetabular replacements achieve a Minimal Clinically Important Difference (MCID) in more than 80% of cases. PATIENTS AND METHODS: Fifty-five hips underwent acetabular revision between 2011 and 2020. Forty-three were performed as first-line surgery, eight after failed tenotomy and four after failed anterior hip capsule thickening plasty. A CT scan of all the hips revealed a median overhang of 9 mm (7; 12) and a 7 ° cup anteversion (2; 19). Follow-up included assessment of the Oxford-12 score using MCID and PASS, the Merle d'Aubigné score, an assessment of hip flexion muscle strength using the Medical Research Council scale, and an assessment of satisfaction and complications. RESULTS: At a mean follow-up of 3 years (2-10), the difference in the Oxford score before and at follow-up was 18 points (15; 27) (p < 0.001), the median Medical Research Council score was 4.5 (4; 5) and patients were satisfied or very satisfied in 73% of cases (40/55). The MCID was achieved for 87% of the hips (48/55), and the PASS was achieved in 67% of cases (33/55). The rate of complications involving surgical revision was 10.9% (6/55) with respectively: two anterior dislocations, one early infection on day 10 resolved after wound irrigation and appropriate antibiotic therapy, one intraoperative fracture of the trochanter requiring osteosynthesis and one arthroscopic revision to remove a free cement fragment. CONCLUSION: Due to a good functional outcome but a high complication rate, a cup replacement can be offered for iliopsoas impingement associated with acetabular malposition or significant overhang. LEVEL OF EVIDENCE: IV.

Loss of walking independence one year after primary total hip arthroplasty for osteonecrosis of the femoral head: incidence and risk prediction model.

BACKGROUND: Assessment of postoperative ambulation in osteonecrosis of the femoral head (ONFH) patients treated with total hip arthroplasty (THA) is limited. This study aimed to define the incidence and risk factors for losing walking independence (LWI) at one-year postoperatively in patients with ONFH undergoing primary THA, and to establish and validate a predictive nomogram. METHODS: This was a retrospective analysis of prospective collected data from patients admitted to a tertiary referral hospital with ONFH who underwent primary unilateral THA from October 2014 to March 2018. The Functional Independence Measure-Locomotion scale was used to quantify walking independence and was documented at a one-year continuous postoperative follow-up, which classified patients with a final score below 6 as LWI. Multivariate logistic regression identified independent risk factors for LWI, and a predictive nomogram was constructed based on the analysis results. The stability of the model was assessed using patients from April 2018 to April 2019 as an external validation set. RESULTS: 1152 patients were enrolled in the study, of which 810 were used in the training cohort and the other 342 for the validation cohort. The incidence of LWI was 5.93%. Multivariate analysis revealed that age 62 years or older (odd ratio (OR) = 2.37, 95% confidence interval (CI) 1.07-5.24), Charlson's comorbidity index 3 or higher (OR = 3.64, 95% CI 1.09-12.14), Association Research Circulation Osseous stage IV (OR = 2.16, 95% CI 1.03-4.54), reduced femoral offset (OR = 2.41, 95% CI 1.16-5.03), and a higher controlling nutritional status score (OR = 1.14, 95% CI 1.01-1.30) were independent risk factors of LWI. The nomogram had a concordance index of 0.773 and a Brier score of 0.049 in the training set, with corrected values of 0.747 and 0.051 after internal validation. The receiver-operating characteristic curve, calibration curve, Hosmer-Lemeshow test, and decision curve analysis all performed well in both the training and validation cohorts. CONCLUSIONS: This study reported a 5.93% incidence of LWI and established a risk prediction model in patients undergoing THA for ONFH, supporting targeted screening and intervention to assist surgeons in assessing ambulation capacity and managing rehabilitation.

Avascular necrosis of the femoral head: which MRI parameters or findings are more decisive for determining the prognosis?

BACKGROUND: Predicting the development of collapse in patients with avascular necrosis of the femoral head (ANFH) is critical in determining prognosis and management. OBJECTIVE: We aimed to evaluate whether MRI findings and parameters based on the Association Research Circulation Osseous (ARCO), Japanese Investigation Committee (JIC), modified Kerboul, and Mitchell classifications can predict prognosis in patients with early-stage ANFH at initial diagnosis. METHODS: This study comprises a retrospective analysis of early-stage ANFH patients without femoral head collapse. Hips with ANFH were divided into two groups based on whether they developed collapse during at least 1 year of follow-up or not. MRI findings were assessed by two radiologists and compared between the groups. Interobserver reliability was also evaluated. RESULTS: Patients who developed collapse had higher measurements in the percentage of midcoronal area, midsagittal area, maximum coronal area, and total necrotic area (p = 0.001, p = 0.001, p < 0.001, p = 0.003, respectively). Although all AUC values were close to each other, the percentage of maximum coronal area showed the highest AUC value (0.857; 95% CI 0.714-1.000; sensitivity 85.7%, specificity 80%) in ROC curve analysis. Interobserver reliability was best for the JIC and worst for the modified Kerboul classification (Kappa values: 0.890 and 0.492, respectively). No statistically significant difference was found among etiological factors, bone marrow edema, cyst-like changes, synovial effusion, and collapse development (p > 0.05). The double-line sign was statistically significantly more frequent in hips without collapse (p = 0.025). CONCLUSION: The risk of collapse development is higher with a greater volume of necrosis in the femoral head and when the osteonecrosis is located more laterally.

Short-to-Mid-Term Outcomes of Ipsilateral Femoral Head Autograft Combined with Uncemented Total Hip Replacement for Partial Periacetabular Defects Following Tumor Resection.

OBJECTIVE: Periacetabular tumors, especially in young to middle-aged patients with invasive benign tumors or low-grade malignant tumors involving type II or II + III, present significant challenges due to their rarity and the complexity of the anatomical and biomechanical structures involved. The primary difficulty lies in balancing the need to avoid unfavorable oncological outcomes while maintaining postoperative hip joint function during surgical resection. This study aimed to evaluate the effectiveness and reliability of a surgical method involving partial weight-bearing acetabular preservation combined with the use of an uncontaminated femoral head autograft to reconstruct the segmental bone defect after intra-articular resection of the tumorous joint, providing a solution that ensures both oncological safety and functional preservation of the hip joint in these patients. METHODS: We conducted a retrospective study with a follow-up period of at least 36 months. From January 2010 to October 2020, we reviewed 20 cases of patients under 60 year of age with periacetabular invasive benign tumors or primary low-grade malignant tumors. All patients underwent reconstruction of the tumorous joint using autologous femoral head grafts. Data collected included patient age, gender, tumor type, preoperative and postoperative visual analog scale (VAS) scores, Musculoskeletal Tumor Society (MSTS) scores, Harris Hip Scores (HHS), patient survival rates, postoperative tumor recurrence, and surgical complications. To analyze the data, we utilized various statistical methods, including descriptive statistics to summarize patient demographics and clinical characteristics, and paired sample t-tests to compare preoperative and postoperative scores. RESULTS: The study included 20 patients, and a total median follow-up was 83 months. Their pathologic diagnoses comprised 13 giant cell tumors (GCTs), 5 chondrosarcomas, one chondroblastoma, and 1 leiomyosarcoma. Postoperatively, the median differences in vertical and horizontal center of rotation (COR) were 3.8 and 4.0 mm. Median limb length discrepancy (LLD) postoperatively was 5.7 mm (range, 2.3-17.8 mm). Two patients (10%) experienced delayed wound healing, resolved with antibiotics and early surgical debridement. One patient experienced dislocation 3 months postoperatively, which was promptly addressed under general anesthesia without further dislocation. CONCLUSION: Through multiplanar osteotomy with limited margins, femoral head autograft, and uncemented total hip replacement for pelvic segmental bone defects in selected patients in type II or II + III appears to be an encouraging limb-sparing surgery worthy of consideration for carefully selected patients.

Do modifiable patient factors increase the risk of postoperative complications after total joint arthroplasty?

INTRODUCTION: Numerous studies demonstrate that modifiable lifestyle risk factors can influence patient outcomes including survivability, quality of life, and postoperative complications following orthopaedic surgery. The purpose of this study was to determine the impact of modifiable lifestyle risk factors on postoperative medical and surgical complications following a total joint arthroplasty (TJA) in a large national healthcare system. METHODS: A retrospective chart review of a large national health system database was performed to identify patients who underwent TJA between 2017 and 2021. TJA included total knee arthroplasty, total hip arthroplasty, and total shoulder arthroplasty. Modifiable lifestyle risk factors were defined as tobacco use, narcotic drug abuse, hypertension, and diabetes mellitus. Postoperative medical complications and postoperative surgical complications were collected. Logistic regression and odds ratio point estimate analysis were conducted to assess for associations between postoperative complications and modifiable lifestyle risk factors. RESULTS: Of the 16,940 patients identified, the mean age was 71 years, mean BMI was 29.7 kg/m2, and 62% were women. We found that 3.5% had used narcotics, 8.7% were past or current smokers, 24% had diabetes, and 61% had hypertension; in addition, 5.4% experienced postoperative medical complications and 6.4% experienced postoperative surgical complications. Patients who used narcotics were 90% more likely to have postoperative complications (p < 0.0001) and 105% more likely to experience prosthetic complications (p < 0.0001). Similarly, patients with tobacco use were 65% more likely to have postoperative complications (p < 0.0001) and 27% more likely to experience prosthetic complications. CONCLUSIONS: Our results demonstrate critical rates of increased postoperative medical and surgical complications after TJA for patients with narcotic abuse, tobacco use, or diabetes mellitus. Furthermore, adopting preoperative interventions and optimization programs informed by our findings on specific modifiable risk factors could aid orthopaedic surgeons in optimizing patient health. LEVEL OF EVIDENCE: III; Retrospective study.

[Endoprosthetic treatment of femoral neck fractures in Germany : Cumulative analysis of EPRD registry data from 2013 to 2020]. / Endoprothetische Versorgung von Schenkelhalsfrakturen in Deutschland : Kumulative Analyse der Registerdaten des EPRD von 2013 bis 2020.

BACKGROUND: The German Arthroplasty Registry (EPRD) recorded nearly 52,000 femoral neck fractures treated with arthroplasty by 2020. This study aimed to identify survival rates and risk factors for hip prosthesis failure. MATERIAL AND METHODS: The study included all patients with arthroplasty after hip fractures documented in the EPRD. Data were analyzed with focus on failure rate regarding implant, implantation technique, age, BMI, and comorbidities. For more complex analysis of dependencies, the machine learning algorithm (MLA) XGBoost (Extreme Gradient Boosting) was used. RESULTS: The study included 51,938 patients. The failure rate was 3.7% for HEs and 5.6% for THA. The failure rate increased in male patients (p < 0.0001), those with higher BMI, young patients with a high Elixhauser Comorbidity Score (ECS) and a cementless technique. The timepoint of surgery, i.e. ,working day vs. weekend or holiday had no influence on the outcome. The feature importance (FI) generated by MLA demonstrated factors with the highest impact on failure, i.e., survival time (1029), BMI (722), and age (481). CONCLUSION: For younger patients with comorbidities, a cemented implantation technique should be considered. Failure rates of arthroplasties did not differ on workdays compared to weekends or holidays. MLA are suitable to analyze registry data for complex correlations of factors.

Does the use of topical vancomycin during primary hip or knee arthroplasty protect from infections?

BACKGROUND: Infection is one of the main complications of hip and knee arthroplasties. Topical application vancomycin to prevent postoperative infections is efficient in spine surgery, and is spreading in prosthetic surgery. However, its clinical relevance and safety are still under debate. Thus, we conducted the present study to (1) assess whether topical vancomycin reduces peri-prosthetic infection rate, and (2) investigate its influence on surgical wound complications. HYPOTHESIS: Our hypothesis was that topical administration of diluted vancomycin during arthroplasty would reduce infection rate within the first postoperative year. MATERIAL AND METHODS: In total, 1900 hip and knee arthroplasties were performed between 2014 and 2021 in a single hospital. From July 2018 and December 2021, 910 prostheses were implanted with intra-articular instillation of vancomycin and tranexamic acid. From November 2014 to June 2018, 990 prostheses were set up without vancomycin. During a follow-up of minimum 12 months, we reported periprosthetic infections occurring during the first postoperative year, as well as vancomycin-induced general or cutaneous complications. RESULTS: We observed periprosthetic infections in 9/990 cases (0.91%) of the control group and 10/910 cases (1.1%) of the vancomycin group (p = 0.82). In parallel, we observed wound complications (erythema, seroma, hematoma, dehiscence and delay in wound healing) in 19/990 (1.9%) and 10/910 cases (1.1%) of the control and vancomycin group, respectively (p = 0.19). There were no general complications resulting from the application of vancomycin. DISCUSSION: Topical diluted vancomycin does not reduce periprosthetic infection risk, and has no effect on the occurrence of surgery wound complications. Considering the present findings, the use of vancomycin cannot be recommended in current practice to prevent infections following hip and knee arthroplasties. Finally, its use does not induce any specific complications, whether local (cicatrisation) or general (related to ototoxicity or nephrotoxicity). LEVEL OF EVIDENCE: III; case control study.

Rice Body Formation in an Enterococcus faecalis-Infected Total Hip Arthroplasty Causing Sciatic Nerve Compression.

We present a case of a 73-year-old lady with a previous uncemented left total hip arthroplasty (THA) three years prior to her current presentation. She presented with an enlarging 'granulomatous'-looking swelling at the distal aspect of her THA scar for three months that was associated with shooting pain from the posterior aspect of her hip radiating down to her foot. The culture and sensitivity of her hip aspirate revealed the growth of Enterococcus faecalis. She underwent revision surgery utilising a 'well-fixed' Exeter custom-made articulating spacer (CUMARS). Intra-operatively, a large encapsulated cyst containing rice bodies was discovered deep within the fascia lata. A complete excision of this cyst was performed. Post-operatively, the patient was treated with two weeks of IV antibiotics and ten weeks of oral antibiotics. Histopathological examination confirmed the presence of rice bodies, with no malignancy seen. We aim to highlight the possibility of rice body cyst formation in the setting of a periprosthetic joint infection (PJI) around a THA and the importance of early treatment in such cases. This is the first published report of a rice body cyst formation in an infected THA.

Does Mal-alignment of the CLS Spotorno Femoral Stem Correlate with Functional Outcome of Patients Undergoing Total Hip Arthroplasty? An Evaluation at Mid-term Follow Up.

Background: The straight and thin design of the CLS Spotorno stem makes it prone for coronal plane mal-alignment, with potential for cortical impingement; reactive osteogenesis and thigh pain have been documented in this situation with some stems. The literature is scarce about the effect of distal mal-alignment with this particular stem, and its relationship with thigh pain, functional outcomes and stem survival. We assessed functional outcomes with incidence of varus/valgus CLS stem alignment, and correlated stem subsidence of these thin stems with hip scores. Methodology: Hip arthroplasty cases with CLS Spotorno stems, operated between 2015 and 2022, with a minimum follow up of 18 months were evaluated. Radiology included 100% pelvis x-rays with bilateral hips (anteroposterior with 15° internal rotation plus lateral views); parameters documented were coronal mal-alignment, stem subsidence, any pedestal formation and heterotrophic ossification (HO); special note was made of any thigh pain, and functional outcomes were recorded using mHHS and SF-36 scores. Results: We evaluated 65 patients with 79 operated hips at an average follow up of 5.26 years. 31.6% (25/79) stems were neutrally aligned, 64.6% (51/79) were in varus alignment and 3.8% (3/79) were in valgus alignment. The mean subsidence was 3.15 mm + 2.26 and 3 cases had Pedestal formation at the stem tip. There was no correlation between varus/valgus stem positions with the mHHS (p = 0.271) and SF-36 score (p = 0.553), which also did not correlate with the stem subsidence. HO formation was seen in 16 hips (20.3%), but no cases in our series needed revision during follow up. Conclusion: Significant distal malalignment with some subsidence were noted in the hips studied; despite these radiological issues, there were excellent mid-term outcomes and good stems survival, implying that distal malposition may have no bearing on functional outcomes.

A Radiological Comparison of Robotic-Assisted Versus Manual Techniques in Total Hip Arthroplasty.

Purpose: This study investigates the radiological outcomes of robotic-assisted total hip arthroplasty (RATHA) compared to manual total hip arthroplasty (mTHA), addressing the ongoing debate on the effectiveness of RATHA in achieving superior implant positioning accuracy. Methods: A prospective cohort of 212 patients (103 robotic, 109 manual) underwent THA and were evaluated for postoperative radiological outcomes, focusing on the inclination and anteversion angles of the acetabular cup. Outlier prevalence was assessed based on angles outside the defined Lewinnek safe zones. All post-operative measurements were made using the BoneNinja application. Results: High inter-observer and intra-observer reliabilities were observed, validating the measurement accuracy. The mean anteversion and inclination angles in the RATHA cohort were 40.5 ± 1.5 and 24.5 ± 3.1° respectively; and the mTHA cohort were 42.1 ± 4.9 and 24.9 ± 4.5°. There was a statistically significant difference in inclination angles between the two cohorts whereas the anteversion angles showed no difference. Majority of the conventional THRs (N = 72, 55.4%) were placed outside the safe zone for anteversion. The inclination angles revealed a highly significant difference between the cohorts (p < 0.0001), with all the robotic THRs (N = 121, 100%) being placed within the safe zone for inclination, whereas only 70% (N = 91) of the conventional THRs were within the safe zone. 97.5% of RA-THRs were within 3° of the proposed plan, demonstrating high accuracy. Conclusion: RATHA significantly outperforms MTHA in radiological accuracy, achieving precise acetabular cup positioning with minimal outliers. These results advocate for RATHA's adoption in THA to enhance outcome predictability and affirm its reliability and safety over manual methods.

Kinematic-kinetic compliant acetabular cup positioning based on preoperative motion tracking and musculoskeletal modeling for total hip arthroplasty.

The invention of the surgical robot enabled accurate component implantation during total hip arthroplasty (THA). However, a preoperative surgical planning methodology is still lacking to determine the acetabular cup alignment considering the patient-specific hip functions during daily activities such as walking. To simultaneously avoid implant edgeloading and impingement, this study established a kinematic-kinetic compliant (KKC) acetabular cup positioning method based on preoperative gait kinematics measurement and musculoskeletal modeling. Computed tomography images around the hip joint and their biomechanical data during gait, including motion tracking and foot-ground reaction forces, were collected. Using the reconstructed pelvic and femur geometries, the patient-specific hip muscle insertions were located in the lower limb musculoskeletal model via point cloud registration. The designed cup orientation has to be within the patient-specific safe zone to prevent implant impingement, and the optimized value selected based on the time-dependent hip joint reaction force to minimize the risk of edgeloading. As a validation of the proposed musculoskeletal model, the predicted lower limb muscle activations for seven patients were correlated with their surface electromyographic measurements, and the computed hip contact force was also in quantitative agreement with data from the literature. However, the designed cup orientations were not always within the well-known Lewinnek safe zone, highlighting the importance of KKC surgical planning based on patient-specific biomechanical evaluations.

Reconstruction of severe acetabular defects (Paprosky type III A) in total hip arthroplasty using modular tantalum augments in combination with a cemented cup.

PURPOSE: Acetabular defect reconstruction can be a complex and challenging surgical procedure, with stable long-term fixation of the implants remaining the ultimate goal. The purpose of this study was (1) to evaluate the radiological and clinical outcome of complex acetabular reconstruction surgery with the use of modular tantalum TM augments in combination with cemented revision cups; (2) to investigate blood tantalum concentrations in these patients; and (3) to report complications and mechanisms of failure related to this procedure at mid-term follow-up (mean 4.5 years). METHODS: We retrospectively reviewed 29 patients (29 hips) with severe acetabular bone loss (Paprosky type III A) reconstructed using a modular tantalum TM augment in combination with a cemented cup. We evaluated the implant survival and the radiological and clinical outcomes after a mean follow-up of 4.5 years (SD 2.2; range 8.4 - 2.1 years) using patient reported outcome scores (PROMs). Blood samples were analysed regarding tantalum concentration and compared with a control group. RESULTS: The cumulative survival rate at 4.5 years with the endpoint "revision of the acetabular component for any reason" was 96.2% (95% Confidence Interval 75.7-99.5). The PROMs improved significantly up to the latest follow-up, and radiographic data showed only one patient with signs of initial implant migration with a broken screw and a change of the position of the augment and the cup. Mean blood tantalum concentrations were significantly higher in the study group (0.16 µg/L) compared to the control group (0.002 µg/L) (P < 0.001). CONCLUSIONS: This study has demonstrated good mid-term (mean 4.5 years) clinical and radiological outcomes of modular tantalum TM augments in combination with a cemented cup for the reconstruction of major acetabular defects. Mean blood tantalum concentrations were increased in patients with stable tantalum implants compared to healthy controls.

Age, activity, and native femoral offset are associated with articular noise in ceramic on ceramic total hip arthroplasty (THA) with custom stems.

PURPOSE: To report the prevalence of articular noise following total hip arthroplasty (THA) with custom stems and ceramic-on-ceramic (CoC) bearings, to determine the risk factors for articular noise, and the effect of articular noise on quality of life (QoL). METHODS: A consecutive series of uncemented primary THAs using custom stems implanted between 01/02/ 2014-01/04/2017 were evaluated. The cohort comprised 479 patients (529 hips, 301 males and 228 females), aged 55.9 ± 11.6 with a BMI of 25.8 ± 4.3 kg/m2. Postoperative assessment included Oxford hip score (OHS), forgotten joint score (FJS), and a dedicated questionnaire on articular noise. Descriptive statistics were used to summarise the data. Regression analyses were performed to study factors associated with presence of noise. RESULTS: At a minimum follow-up of five years, 431 patients (476 hips) were available for postoperative assessment. OHS was 45.3 ± 6.1, FJS was 83.6 ± 24.7, and 69 patients (71 hips, 15%) reported articular noise. The impact of noise on QoL was 1.4 ± 2.1. Multivariable analyses confirmed that the presence of articular noise was associated with younger age (OR,0.95; 95%CI,0.93-0.97; p < 0.001), smaller native femoral offset (OR, 0.95; 95%CI,0.90-1.00;p = 0.034), as well as intense (OR, 3.15; 95%CI, 1.15-9.79; p = 0.033) and very intense physical activity (OR, 4.71; 95%CI, 1.52-16.15; p = 0.009). CONCLUSION: The prevalence of articular noise following primary THA with custom stems and CoC bearings was 15%, but the impact of noise on QoL was minimal for most patients. Younger, highly active patients should be advised of an increased likelihood of noise from CoC THA, particularly if they have low native femoral offset on preoperative imaging.

6-year follow-up on migration outcomes: a randomised clinical trial of cemented vitamin E-stabilised highly crosslinked versus standard polyethylene cup in total hip arthroplasty.

BACKGROUND: In a previous study we have shown that a cemented vitamin E-doped highly cross-linked polyethylene (VEPE) compared to a conventional polyethylene cup in total hip arthroplasty (THA) has a slightly higher proximal migration but significantly lower wear rates up to 2 years after surgery. In this follow-up study we investigated the same cohort at 6 years. METHODS: This was a double-blinded, non-inferiority, randomised controlled trial on patients with osteoarthritis, with a mean age of 66 years. Patients were randomly assigned to receive either the conventional polyethylene cup or the VEPE cup in a 1:1 ratio. The primary endpoint was proximal implant migration of the cup measured with radiostereometric analysis (RSA). Secondary endpoints included wear rate of the cup and patient-reported outcome measurements (PROM). RESULTS: At the 6-year follow-up, 25 patients (11 controls, 14 VEPE) were available for RSA measurements, and we found no statistically significant difference in proximal migration between the VEPE and control groups. The wear rate was significantly lower in the VEPE group compared to controls, 0.03 mm/year and 0.07 mm/year, respectively with a mean difference 0.04 mm, (95% CI, 0.02-0.06 mm). There were no cup revisions and no difference in PROM between the groups. CONCLUSIONS: Based on our 6-year results, the VEPE group exhibited no statistical or clinically relevant difference compared to the control group, and the wear rate was significantly lower in the VEPE group. The use of a cemented vitamin E-doped highly cross-linked cup is a good option in total hip arthroplasty.

Comparative analysis of patient-reported outcomes in total knee arthroplasty and total hip arthroplasty: adjusting for demographic influences.

PURPOSE: Total knee arthroplasty (TKA) has consistently demonstrated lower patient satisfaction compared to total hip arthroplasty (THA). However, prior investigations failed to account for the patients' demographic characteristics. This study aimed to conduct a comparative analysis of patient-reported outcomes between TKA and THA while adjusting for patient background. METHODS: A total of 326 primary TKAs and 259 THAs conducted at a single center were assessed using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores preoperatively and at 3 months, 1 year, and 2 years postoperatively. Notably, TKA patients exhibited advanced age and higher body mass index (BMI) than their THA counterparts. To mitigate the impact of these differences, we employed propensity score-matched data, adjusting for background characteristics such as age, gender, BMI, and diagnosis. RESULTS: THA consistently demonstrated significantly superior WOMAC total, pain, and stiffness scores compared to TKA at 3 months, 1 year, and 2 years postoperatively. Nevertheless, no statistically significant disparity in WOMAC physical function scores was observed between the two groups at 3 months and 1 year postoperatively in the matched data (3 months, p = 0.131; 1 year, p = 0.269). CONCLUSION: In contrast to earlier findings, our analysis of propensity score-matched data revealed no significant differences in WOMAC physical function scores between the TKA and THA groups at 3 months and 1 year postoperatively. The distinctive background factors observed in patients undergoing TKA and THA, notably advanced age and higher BMI, coupled with the delayed improvement timeline in TKA's WOMAC scores compared to that of THA, have the potential to impact patient-reported outcomes. Consequently, clinicians should be mindful of the potential impact of patient background on variations in patient-reported outcome measures following total joint arthroplasty.

The role of MRI in the diagnosis of aseptic loosening following total hip arthroplasty.

INTRODUCTION: The role of advanced imaging in diagnosing aseptic implant loosening following total hip arthroplasty (THA) remains unclear. This study aimed to assess the diagnostic value of magnetic resonance imaging (MRI) in detecting aseptic loosening. METHODS: This was a retrospective review of 342 consecutive patients who underwent revision THA between July 2011 and April 2023 and had a pelvis MRI as part of the preoperative diagnostic evaluation. Among them, 62 patients had an intraoperative diagnosis of aseptic loosening of either the femoral or acetabular component. Patients were stratified based on the concordance between their MRI and radiographs findings. RESULTS: Preoperative MRI showed signs of aseptic loosening in 25/62 patients (sensitivity = 40.3%). Similarly, preoperative radiographs demonstrated signs of aseptic loosening in 27 patients (43.5%). Twelve patients (19.4%) had both MRI and radiographs predictive of aseptic loosening, 22 patients (35.5%) did not show signs of aseptic loosening in either MRI or radiographs, and for 28 patients (45.2%), the results were discordant. Among the patients with a negative radiograph for aseptic loosening (n = 35), 13 patients (37.1%) showed signs of aseptic loosening on MRI. CONCLUSION: Aseptic loosening remains an elusive diagnosis, and the findings of this study suggest that the utility of MRI and radiographs as part of the diagnostic process is limited. However, in cases of presumed aseptic loosening with inconclusive radiographs findings, MRI may play a role in improving the diagnostic process. LEVEL OF EVIDENCE: III.