Total Hip Replacement Arthroplasty Research Articles

Contemporary insights into spinopelvic mechanics.

Understanding spinopelvic mechanics is important for the success of total hip arthroplasty (THA). Despite significant advancements in appreciating spinopelvic balance, numerous challenges remain. It is crucial to recognize the individual variability and postoperative changes in spinopelvic parameters and their consequential impact on prosthetic component positioning to mitigate the risk of dislocation and enhance postoperative outcomes. This review describes the integration of advanced diagnostic approaches, enhanced technology, implant considerations, and surgical planning, all tailored to the unique anatomy and biomechanics of each patient. It underscores the importance of accurately predicting postoperative spinopelvic mechanics, selecting suitable imaging techniques, establishing a consistent nomenclature for spinopelvic stiffness, and considering implant-specific strategies. Furthermore, it highlights the potential of artificial intelligence to personalize care.

The worldwide survival rate of total hip arthroplasties is improving: a systematic comparative analysis using worldwide hip arthroplasty registers.

The aim of this study was to evaluate the development of the worldwide survival rate of primary total hip arthroplasty (THA). The hypothesis was that survival improved over the last decade in worldwide arthroplasty registers. THA registers were screened in 2022 and compared between different countries with respect to the number of primary implantations per inhabitant, age, fixation type, and survival rate, and compared to similar data from 2009. The data from these reports were analyzed in terms of number, age distribution, and procedure type of primary THAs. Survival curves and a comparative analysis with respect to the development over time were calculated. We identified nine hip arthroplasty registers that contained sufficient data to be included. A large variation was found in the annual number of primary THA implantations per inhabitant, with more than the factor 4 for all age groups across regions. The procedure type varied strongly as well, e.g. in Sweden, 50% were cemented THAs, whereas in Emilia-Romagna (Italy), 96% of THAs were implanted cementless. We found an improved survival rate of 5%, with 90% of survival after 15 years in the cohorts from 2021 compared to 85% in the cohorts from 2009. The present study revealed a significant improvement in the survival of THA in worldwide arthroplasty registers within different countries and regions over the period of one decade. We believe that it is safe to state that the success of THA is still rising with respect to this main outcome.

Comparison between Total Hip Arthroplasty for Avascular Osteonecrosis of Femoral Head and That for Fixation Failure of Femoral Neck Fracture

Objective: To compare the clinical and radiologic results between primary total hip replacement arthroplasty (THRA) in patients with avascular necrosis of femoral head (AVN) and secondary THRA in patients with fixation failure of femoral neck fracture.Methods: From March 2014 to February 2021, we retrospectively evaluated a total of 53 patients who underwent either THRA for AVN (33 cases) or THRA for fixation failure of femoral neck fracture (20 cases). Clinical performances and Hemodynamic scales were evaluated. Radiologic analyses were conducted to assess stem alignment, stem stability, the appearance of heterotrophic ossification, stress shielding, and any signs of osteolysis or loosening.Results: THRA for AVN showed a mean blood loss of 881 mL and a 2.1 g/dL preoperative–postoperative (preop–postop) hemoglobin (Hb) difference. Meanwhile, THRA for fixation failure of femoral neck fracture showed a mean blood loss of 1,072 mL and a 3.2 g/dL preop–postop Hb difference (P= 0.017 and P= 0.034, respectively). The mean operation time was 70 minutes in THRA for AVN and 91 minutes in THRA for fixation failure of femoral neck fracture (P= 0.035). Stem alignment was varus 1.50° in AVN and varus 3.50° in fixation failure of femoral neck fracture. There was one case of a varus femoral stem in AVN and six such cases in the fixation failure of femoral neck fractures. This was a statistically significant difference (P= 0.010 and P= 0.020, respectively).Conclusion: Secondary THRA in patients with fixation failure of femoral neck fracture showed longer operation time, larger bleeding, and more varus stem alignment than primary THRA in patients with AVN.

Zoledronic Acid and Enriched Autologous Bone Marrow Stem Cell Implantation for Femoral Head Osteonecrosis.

This study evaluated the clinical results of zoledronic acid in the treatment of early osteonecrosis of the femoral head (ONFH). Study retrospectively analyzed 60 patients with zoledronic acid with bone marrow stem cell(BMSC) implantation (The study group) and 64 patients with BMSC implantation (The control group). The primary evaluation index included VAS, HHS, collapsed rate, and total hip replacement arthroplasty (THA) conversion rate. The study group had a lower VAS (1.12 ± 0.22 vs 1.44 ± 0.32) and higher HHS (75.07 ± 3.66 vs 68.78 ± 2.24) compared to the control group in 6months after surgery (P < 0.05). In the study group, 12 hips (20%) collapsed, and 7 of 60 hips (11.67%) required THA surgery at the last follow-up. However, 25 hips (38.8%) collapsed in the control group, and 19 hips (29.69%) required THA surgery. The study group had a lower collapsed rate (P = 0.029) and THA conversion rate (P = 0.016) in survival analysis. Zoledronic acid and BMSC implantation in the treatment of early ONFH is safe and effective, reduces pain shortens recovery time, and reduces collapsed rate and THA conversion rate in ONFH patients.

Can machine learning predict the accuracy of preoperative planning for total hip arthroplasty, basing on patient-related factors? An explorative investigation on Supervised machine learning classification models.

BackgroundThe success of Total Hip Arthroplasty (THA) is influenced by preoperative planning, with traditional 2D approaches displaying varied reliability as well. The present study investigates the use of Supervised Machine Learning (SML) models with patient-related features to improve accuracy. MethodsPreoperative and perioperative data, as well as planning and final implant information, were obtained from 800 consecutive cementless primary THA, which was performed uniformly by a specialized surgical team. Six Supervised Machine Learning models were trained and validated using patient characteristics and implant data: Logistic Regression (LR), Linear Discriminant Analysis (LDA), K-Nearest Neighbors (KNN), Decision Tree (CART), Gaussian Naive Bayes (GN), and Support Vector Classifier (SVC). The models' ability to predict planning reliability and leg length disparity was evaluated. ResultsKNN performed better on the cup model (97.9 %), femur model (96.7 %), and femur size (99.2 %). SVM emerged as the model with the highest accuracy for cup size (60.4 %) and head size (62.1 %). CART had the best accuracy (99 %) when determining leg length discrepancy. ConclusionThe study demonstrates the utility of Supervised Machine Learning models, specifically KNN, in predicting the accuracy of preoperative planning in THA. The accuracy of these models, which are driven by patient-related characteristics, provides useful information for optimizing patients’ selection and improving surgical outcome.

Intraoperative live measurement of femoral head size for acetabular cup sizing: simple, accurate, and green!

Templating is the first step in achieving a successful total hip arthroplasty. We hypothesize that native head size is highly correlated with implanted cup size. Therefore, the purpose of this study is to look for a correlation between sizes of the intra-operative measurement of the femoral head and the implanted cup. This is a monocentric observational study conducted from December 2018 till January 2023. All patients admitted for a primary total hip arthroplasty were included and retrospectively reviewed. Intra-operative femoral head measurement, radiographic femoral head diameter, templated (planned) cup size, and definitive implanted cup size were recorded. The sample included 154 patients (85 female and 69 males) with a mean age of 66.2 ± 10.4years. There were 157 THA cases; 82 on the right side and 75 on the left side. The native head size and acetate template on digital radiographs were the most significantly positively correlated with cup size (P < 0.0001) while the radiological head size was significantly negatively correlated with cup size (P = 0.009). The implanted cup was on average 2 ± 2mm bigger than the native head size measured intra-operatively. The native femoral head diameter measured intra-operatively is a simple and reliable tool to help the surgeons choose the proper size of the acetabular cup, preventing complications during surgery hence optimizing results post operatively. This technique would contribute to a more ecofriendly orthopaedic reconstructive surgery.

Robotic-Assisted Hip and Knee Arthroplasty: A Bibliometric Analysis Using the Scopus Database.

Robotic-assisted hip and knee arthroplasty represents cutting-edge advancements in orthopedic surgery, harnessing robotic technology to enhance precision, improve clinical outcomes, and facilitate intra-operative procedures. In these robotic-assisted surgeries, the robotic systems assist surgeons in planning and executing joint replacement surgeries, thereby facilitating personalized implant positioning and optimizing the fit and alignment of hip and knee implants. Despite the increasing attention garnered by robotic-assisted hip and knee arthroplasty in recent years, a comprehensive bibliometric analysis using the Scopus database has yet to be conducted. This bibliometric analysis reviews the Scopus database from 1961 until 2022 to investigate the literature on the field of robotic-assisted hip and knee arthroplasty. A total of 577 articles that satisfied the selection criteria were included in this review. The majority of the articles focus more on total knee replacement, compared to total hip replacement and unicompartmental knee arthroplasty. The overwhelming majority of the articles were authored by researchers and clinicians from the United States of America (USA) and the United Kingdom (UK). Similarly, most of the articles with the highest number of citations were authored by researchers and clinicians from these regions. This comprehensive bibliometric analysis using Scopus in the domain of robotic-assisted hip and knee replacement has the potential to act as a roadmap for researchers, clinicians, and policymakers, facilitating informed decision-making, promoting collaborative initiatives, and guiding the development of future studies to further advance the field of robotic-assisted hip and knee arthroplasty.

Which factors are associated with a successful outcome following total hip arthroplasty in patients with early radiographic osteoarthritis?

It is unclear which factors are associated with a successful total hip arthroplasty (THA) in patients with early radiographic osteoarthritis (OA). 70 patients with early OA (Kellgren and Lawrence [KL] grades 0-2) who underwent THA were compared with 200 patients with advanced OA (KL grades 3-4). Outcomes were Oxford Hip Scores (OHS), EQ-5D and EQ-VAS scores; compared preoperatively with 1 year postoperatively. We investigated which clinical and radiographic (plain x-ray, CT, MRI) features predicted successful THA (postoperative OHS ⩾42). The early OA group were significantly younger (61 vs. 66 years; [p = 0.0035). There were no significant differences in BMI, ASA grade or gender. After adjusting for confounders, the advanced OA group had a significantly greater percentage of possible change (PoPC) in OHS (75.8% vs. 50.4%; p < 0.0001) and improvement in EQ-5D (0.151 vs. 0.002; p < 0.0001). There were no significant differences in complication, revision or readmission rates. In the early OA group, 16/70 (22.9%) patients had a 'successful' THA. Patients who had a 'successful' THA were significantly more likely to have subchondral cysts on CT/MRI (91.7% vs. 57.7%; p = 0.0362). The presence of cysts on CT/MRI was associated with a significantly greater PoPC in OHS (61.6% vs. 38.2%; p = 0.0353). The combination of cysts and joint space width <1 mm was associated with a PoPC of 68%. THA in patients with early OA (KL grades 0-2) on plain radiographs should be indicated with caution. We advocate preoperative cross-sectional imaging in these patients. In the absence of cysts on CT/MRI, a THA seems unlikely to provide a satisfactory outcome.

Application and evaluation of artificial intelligence 3D preoperative planning software in developmental dysplasia of the hip

BackgroundAccurate preoperative planning is crucial for successful total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH). The aim of this study was to compare the accuracy of an artificial intelligence-assisted three-dimensional (3D) planning system (AIHIP) with two-dimensional templates in predicting acetabular cup size in THA for DDH.MethodThis study retrospectively analyzed image data from 103 DDH patients who had THA between May 2019 and August 2023. AIHIP was used for 3D planning, and two-dimensional (2D) templates were used by two experienced surgeons. Accuracy was assessed by comparing predicted and actual cup sizes, and potential factors affecting accuracy were analyzed, including gender, side, BMI, and dysplasia classification.ResultsAIHIP had higher accuracy in predicting the acetabular cup size compared to the 2D template. Within ± 0 size, AIHIP’s accuracy was 84.1%, while the 2D template’s was 64.0% (p < 0.05). Within ± 1 size, AIHIP's accuracy was 95.1%, while the 2D template’s was 81.1% (p < 0.05). Accuracy was unaffected by gender, side, or BMI but was by DDH classification. In subgroup analysis, AIHIP's mean absolute error (0.21 ± 0.54) was significantly lower than the 2D template’s (0.62 ± 0.95) for Crowe II and Crowe III (p < 0.05).ConclusionAIHIP is superior to 2D templates in predicting the acetabular cup size accurately for THA in DDH patients. AIHIP may be especially beneficial for Crowe II and III DDH patients, as 2D templates may not accurately predict cup size in these cases.

Accuracy of femoral component anteversion in robotic total hip arthroplasty.

Femoral component anteversion is an important factor in the success of total hip arthroplasty (THA). This retrospective study aimed to investigate the accuracy of femoral component anteversion with the Mako THA system and software using the Exeter cemented femoral component, compared to the Accolade II cementless femoral component. We reviewed the data of 30 hips from 24 patients who underwent THA using the posterior approach with Exeter femoral components, and 30 hips from 24 patients with Accolade II components. Both groups did not differ significantly in age, sex, BMI, bone quality, or disease. Two weeks postoperatively, CT images were obtained to measure acetabular and femoral component anteversion. The mean difference in femoral component anteversion between intraoperative and postoperative CT measurements (system accuracy of component anteversion) was 0.8° (SD 1.8°) in the Exeter group and 2.1° (SD 2.3°) in the Accolade II group, respectively (p = 0.020). The mean difference in anteversion between the plan and the postoperative CT measurements (clinical accuracy of femoral component anteversion) was 1.2° (SD 3.6°) in the Exeter group, and 4.2° (SD 3.9°) in the Accolade II group (p = 0.003). No significant differences were found in acetabular component inclination and anteversion; however, the clinical accuracy of combined anteversion was significantly better in the Exeter group (0.6° (SD 3.9°)) than the Accolade II group (3.6° (SD 4.1°)). The Mako THA system and software helps surgeons control the femoral component anteversion to achieve the target angle of insertion. The Exeter femoral component, inserted using Mako THA system, showed greater precision for femoral component and combined component anteversion than the Accolade II component.

Automated digital templating of component sizing is accurate in robotic total hip arthroplasty when compared to predicate software

Accurate pre-operative templating of prosthesis components is an essential factor in successful total hip arthroplasty (THA), including robotically-assisted THA (RA-THA) techniques. We sought to validate the accuracy of a novel, robotic-optimized THA planning software compared to a predicate THA planner for component sizing. We analyzed a series of 199 patients who received manual THA (mTHA) and fluoroscopy-based RA-THA at a single institution. All cases were templated using a predicate pre-operative templating software. For RA-THA cases, the novel robotic-optimized pre-operative planner software was also used for templating. The differences between templated and implanted acetabular cup, femoral head, and stem component sizes were compared based on matching within 1, 2, and ≥3 sizes. Differences in templated and implanted femoral stem implant geometry were also compared. The robot-optimized pre-operative RA-THA plans demonstrated equivalent accuracy to that of predicate pre-operative plans for both RA-THA and mTHA cases. Templated acetabular cups (90.4 vs. 86.8 vs. 82.8; p = 0.421), femoral stems (76.0 vs. 65.1 vs. 67.7; p = 0.096), and femoral heads (91.3 vs. 96.2 vs. 88.2; p = 0.302) were within +/−1 size of implanted components. No significant differences were detected in the proportion of matching templated and implanted stem geometry across the study cohorts.

The use of dual mobility acetabular cups in total hip replacement reduces dislocation rates in hip dysplasia patients

Total hip replacement arthroplasty (THA) in hip dysplasia patients has a higher dislocation rate than in patients with simple hip osteoarthritis due to anatomical deformation. Therefore, to reduce postoperative THA dislocation is the challenge for arthroplasty surgeons. From 2015 to 2020, 1525 patients underwent THA performed by two surgeons at a single institution. A total of 152 patients involving 172 THAs were included. The patients were classified into dual-mobility (DM) and fixed-bearing (FB) acetabular cup groups. The occurrence of postoperative dislocation and functional evaluation of the hip joint, was analyzed before and after surgery using the modified Harris hip score(mHHS). There was no difference in the preoperative demographics and radiographic parameters between the groups. The incidence of postoperative hip dislocation was significantly lower in the DM group (DM 0% vs. FB 9.0%) (P value = 0.003). The mHHS showed no difference before surgery and after surgery (DM 91.80 vs FB 92.03). Treating hip dysplasia patients with THA using a dual-mobility acetabular cup can reduce postoperative dislocations, and could be used for the better management of these patients.

Stem size and stem alignment affects periprosthetic fracture risk and primary stability in cementless total hip arthroplasty.

The ideal stem size and stem position is important for the success of total hip arthroplasty, since it can affect early implant loosening and periprosthetic fractures (PPF). This study aimed to investigate how small deviations from the ideal stem size and position influences the PPF risk and primary stability. Six experienced surgeons performed preoperative templating based on which the benchmark size for each femur was determined. Consecutive implantations were performed in six cadaveric femur pairs-one side was implanted with an undersized stem followed by the benchmark size and the contralateral side with a benchmark size followed by an oversized stem (Corail, Depuy Synthes). Moreover, three different alignments (six varus, six neutral, six valgus-undersized) were compared using 18 femurs. Cortical strains during broaching and implantation were measured, and laser scans were used to determine final stem position. All specimens underwent dynamic loading. Primary stability was estimated from stem subsidence and pull-out forces. Templated stem size varied between surgeons (±1 size; p = 0.005). Undersizing increased stem subsidence by 320% (p < 0.001). Oversized stems exhibited 52% higher pull-out forces (p = 0.001) and 240% higher cortical strains (p = 0.056). Cortex strains increased with varus alignment (R2 = 0.356, p = 0.011) while primary stability decreased with valgus stem alignment (p = 0.043). Surgeons should be aware that small deviations from the ideal stem size and malalignments of the stem can significantly alter the mechanical situation and affect the success of their surgery.

CT-based, robotic-arm assisted total hip arthroplasty (Mako) through anterior approach provides improved cup placement accuracy but no difference in clinical outcomes when compared to conventional technique

BACKGROUND: With the restoration of the natural hip biomechanics, a successful total hip arthroplasty (THA) and long-term survival is pursued. Although robotic THA (rTHA) has been developed to increase accuracy of implant positioning, leg lengths and offsets, discussions about its radiological and clinical advantages over conventional THA (cTHA) continues. OBJECTIVE: The aim of this study was to compare clinical and radiological outcomes of robotic and conventional THA. METHODS: This retrospective study compares functional and radiological outcomes of 82 rTHA with a matched group of 82 cTHA in terms of age, sex, body mass index and preoperative functional scores. The minimum follow up was 12 months for all patients. Functional outcomes were Harris Hip Score (HHS) and the Western Ontario and McMaster University Osteoarthritis index (WOMAC) evaluated pre- and postoperatively. Radiological evaluations included position of cup placement according to Lewinnek and Callanan safe zones, Canal Fill Ratio (CFR), Leg Length Discrepancy (LLD), Lateral offset (LO) and Femoral Component Alignment (FCA). Complications were also evaluated. RESULTS: In the rTHA group, 91.5% (75 out of 82) of the acetabular cups were positioned within the safe zone whereas it was 63.4% (52 out of 82) for the cTHA group (p&lt; 0.001). According to Callanan, they were 84.1% and 50%, respectively (p&lt; 0.001). Between the groups, no statistically significant difference was found in CFR, LLD, HO, FCA, AI, AA, WOMAC, HHS and major complication rates. CONCLUSION: rTHA is superior to cTHA in terms of accuracy and reproducibility of the cup placement, however no apparent clinical benefit was found in short term follow.

Does Perioperative use of Bisphosphonate Affect Implant Revision Rate of Total Ankle Arthroplasty?

Category: Ankle Arthritis; Other Introduction/Purpose: It is unknown whether perioperative bisphosphonate (BP) use reduces revision rates in total ankle replacement arthroplasty (TAR) although its effect has been demonstrated to be effective in reducing revision rates in total knee or hip replacement arthroplasty. Therefore, the purpose of this study was 1) to investigate whether there is a relationship between the use of BP and the revision rate of TAR, and (2) to determine the effect of BP medication period on the revision rate of TAR. Our hypothesis was that the use of BP would lower the revision rate of TAR. Methods: We reviewed National Health Insurance Service data based on national health insurance service claim data and health care utilization, health screening, socio-demographic variables, medication history, operation codes, and mortality data for 50 million Koreans. From 2002 to 2014, 6391 of 7300 patients who underwent TAR were BP non-users, while 909 patients were BP users. The revision rate according to BP medication and co-morbidities was investigated. The Kaplan-Meier estimate and extended Cox proportional hazard model were also used. Results: The revision rate of TAR was 7.9% for BP users and 9.5% for BP non-users, which showed no significant difference (p=0.251). Implant survival over time decreased constantly. Adjusted hazard ratio for hypertension was 1.242 (p=0.017), while other co-morbidities such as diabetes had no effect on revision rate of TAR. Conclusion: We found that the perioperative BP use do not reduce the revision rate of TAR. Co-morbidities except hypertension did not affect the revision rate of TAR. More research regarding various factor affecting revision of TAR could be warranted.

Free Hip Arthroplasty Templating Software - Does it Work?

Preoperative planning is important for successful total hip arthroplasty (THA) and has been historically performed using acetate templates. Digital software templating has been adopted for evaluating implant size, position, and alignment. Commercial software can be expensive, but free programs exist. Detroit Bone Setter (detroitbonesetter.com, Detroit, MI) is a freely available templating program, but hasn't been validated. Our study reports this program's accuracy for templating THA. Sixty-five patients undergoing THA between 2017 and 2022 at 2 hospitals were included. All cases were templated by the senior author or orthopaedic trauma fellow prospectively or retrospectively in a blinded fashion. Direct anterior or posterior approaches were used based on attending surgeon's preference. A student's t-test was used to compare means of templated vs actual implant sizes of femoral and acetabular components. There was no significant difference between implanted (mean [M]= 6.4, standard deviation [SD]= 2.0) and templated femoral component sizes (M= 5.7, SD= 2.1). There was a significant difference between implanted (M= 57.0, SD= 3.9) and templated acetabular component sizes (M= 53.4, SD= 3.0). Bland-Altman testing demonstrated femoral components with positive measurement bias of 0.62, indicating slight overestimation of implant size. Acetabular component size was overestimated with positive measurement bias of 3.6 mm. Detroit Bone Setter is advantageous as it is freely available and supports most major company implants. It accurately templated femoral component size but consistently overestimated acetabular component size by 3.6 mm. Further studies are needed prior to recommending its routine use for templating THA when other validated methods exist. It could be used with caution when no other methods are available.

Is the Acetabular Cup Orientation Different in Robot-Assisted and Conventional Total Hip Arthroplasty With Right-Handed Surgeons Using an Anterolateral Approach?

Introduction Total hip arthroplasty (THA) is one of the most successful orthopaedic procedures. Survival rates from 90% at 10 years to 93% at 20 years have been reported in different studies. Differences in implant and patient characteristics can undoubtedly explain some of this variability observed in prosthesis durability, but the effect of surgical technique and implant orientation cannot be ignored. Therefore, many intraoperative methods (anatomic landmarks, intraoperative x-ray, fluoroscopy, navigation, and robotic surgery) have been attempted to avoid acetabular component malpositioning.Although postoperative computed tomography (CT) is accepted as the gold standard for the measurement of acetabular anteversion, it remains controversial in respect of costs and radiation exposure. The aim of this study was to examine how acetabular component orientation was affected in robotic and conventional THA operations performed by two surgeons with right-hand dominance. Material and methods The study included 113 primary THA operations performed on 113 patients between 2017 and 2022 in two groups: (i) robotic THA (Mako, Stryker Corporation, Kalamazoo, Michigan, United States) (55 patients) and (ii) conventional THA (58 patients). The patients comprised 51 males and 62 females. THA was performed on 54 right-side hips and 59 left-side hips. The operations were performed by two orthopaedic surgeons, each with 20 years of arthroplasty experience, on all the patients in the lateral decubitus position with an anterolateral approach. In all the cases, the orientation of the acetabular component was 40° inclination and 20° anteversion. Difficult THA procedures (patients with developmental dysplasia of the hip (DDH), a history of hip surgery, revision THA, defect or deformity of the acetabulum, a history of scoliosis or lumbar posterior surgery, or those requiring proximal femoral osteotomy) were excluded from the study. Using the Liaw and Lewinnek methods, the acetabular component anteversion was measured on the radiographs taken in the optimal position postoperatively and the acetabular cup inclination angles were measured on the pelvis radiographs. The groups were compared using the Kolmogorov-Smirnov, Pearson Chi-square and Mann-Whitney U statistical tests. The limits were accepted as 40±5° for inclination and 20±5° for anteversion. Results No statistically significant difference was determined between the groups in respect of age, gender, or operated side. No statistically significant difference was determined between the optimal acetabular cup inclination angles of the robotic and conventional THA groups (p = 0.79). No statistically significant difference was determined between the optimal acetabular cup anteversion angles of the left and right conventional THA groups. Statistically significantly better results were determined in the robotic group in respect of acetabular cup anteversion (p<0,001). Conclusion The optimal orientation of the acetabular component is a key factor for successful THA. Otherwise, revision surgery is inevitable for reasons such as instability, impingement, or increased wear. The results of this study demonstrated that robotic surgery was superior to the conventional method in the placement of the acetabular component in the desired orientation.

Metal-on-crosslinked polyethylene in total hip arthroplasty - an excellent combination at fifteen to twentyyears of follow-up.

Cross-linked polyethylene (PE) has been used with great clinical success in total hip arthroplasty (THA) since its debut in the late 1990's. However, reports regarding this bearing couple near the end of its second decade of service are still scant. The aim of this study was to first determine the long term clinical and radiological results and second Investigate what factors affect wear rates using a metal-on-crosslinked PE bearing articulation. 55 THAs using a single brand of cross-linked liner, cementless cup and 28mm hip ball were performed in 44 patients. Age, sex, Charlson Comorbidity Index (CCI) and need for revision surgery were recorded. Linear and volumetric wear was determined using the Martell method. Mean age at operation was 51.2 (29-73 ± 12.1) years. Mean duration of follow-up was 16.9years (range 15.0-20.1 ± 1.1years). Osteolysis was not present in the latest follow-up radiographs. Median linear and volumetric wear rate was 0.038mm/year (95% CI 0.032-0.047) and 7.115mm3/year (95% CI 6.92-17.25) respectively. Acetabular component position was not found to be related to both linear and volumetric wear. No significant difference was found in the linear and volumetric wear rates of thinner and thicker liners (8mm or below and > 8mm) (p = 0.849 and p = 0.64 respectively). Metal-on-crosslinked PE is associated with low linear and volumetric wear rates which has virtually obviated osteolysis and has translated to excellent survivorship even at long term follow up. In-vivo oxidation does not appear to be of clinical concern at this point.

Does Perioperative Use of Bisphosphonate Affect the Implant Revision Rate of Total Ankle Arthroplasty?

It is unknown whether perioperative bisphosphonate (BP) use reduces revision rates in total ankle replacement arthroplasty (TAR) although its effect has been demonstrated to be effective in reducing revision rates in total knee or hip replacement arthroplasty. We reviewed National Health Insurance Service data based on national health insurance service claims data and health care utilization, health screening, sociodemographic variables, medication history, operation codes, and mortality data for 50 million Koreans. From 2002 to 2014, 6391 of 7300 patients who underwent TAR were BP nonusers, whereas 909 patients were BP users. The revision rate according to BP medication and comorbidities was investigated. The Kaplan-Meier estimate and extended Cox proportional hazard model were also used. The revision rate of TAR was 7.9% for BP users and 9.5% for BP nonusers, which showed no significant difference (P = .251). Implant survival over time decreased constantly. Adjusted hazard ratio for hypertension was 1.242 (P = .017), whereas other comorbidities such as diabetes had no effect on the revision rate of TAR. We found that the perioperative BP use did not reduce the revision rate of TAR. Comorbidities (except hypertension) did not affect the revision rate of TAR. More research regarding various factors affecting the revision of TAR could be warranted. Level III, retrospective cohort study.

Validation of a Novel Method of Measuring Cup Orientation Using BiPlanar Simultaneous Radiographic Images

BackgroundAccurate acetabular component positioning is paramount to the success of total hip arthroplasty (THA). Two-dimensional imaging alone remains a popular tool for implant position assessment despite known limitations. We investigated the accuracy of a novel method for assessing acetabular component position based upon orthogonal simultaneous biplanar X-ray images. MethodsThere were forty consecutive patients who had a preexisting THA on the contralateral side who underwent both computed tomography (CT) and simultaneous orthogonal biplanar radiographic scans for preoperative planning of THA. The operative inclination (OI) and operative anteversion (OA) of the acetabular cup were calculated by a new measurement method using the biplanar simultaneous scans. Those measurements were compared to measurement of the cup orientation on CT. The measurements were made by 2 independent observers. Interobserver correlation coefficients were calculated between the 2 observers to measure reliability. ResultsThe mean error in OA measurement of the acetabular cup between simultaneous orthogonal biplanar radiographic and CT imaging was 0.5° (SD: 1.9°, minimum −4.0°, maximum 5.0°), the mean error in OI was 0.0° (SD: 1.7°, minimum −5.0°, maximum 4.0°). The average absolute error was 1.5° for OA and 1.2° for OI. Interobserver correlation coefficient was 0.83 for OA and 0.93 for OI. ConclusionThe novel method of measuring cup orientation using simultaneous biplanar radiographic scans utilized in this study was accurate and reproducible between observers compared to CT measurements.