Assessment of Automated Identification of Phases in Videos of Total Hip Arthroplasty Using Deep Learning Techniques.

Background: As the population ages, the rates of hip diseases and fragility fractures are increasing, making total hip arthroplasty (THA) one of the best methods for treating elderly patients. With the increasing number of THA surgeries and diverse surgical methods, there is a need for standard evaluation protocols. This study aimed to use deep learning algorithms to classify THA videos and evaluate the accuracy of the labelling of these videos. Methods: In our study, we manually annotated 7 phases in THA, including skin incision, broaching, exposure of acetabulum, acetabular reaming, acetabular cup positioning, femoral stem insertion, and skin closure. Within each phase, a second trained annotator marked the beginning and end of instrument usages, such as the skin blade, forceps, Bovie, suction device, suture material, retractor, rasp, femoral stem, acetabular reamer, head trial, and real head. Results: In our study, we utilized YOLOv3 to collect 540 operating images of THA procedures and create a scene annotation model. The results of our study showed relatively high accuracy in the clear classification of surgical techniques such as skin incision and closure, broaching, acetabular reaming, and femoral stem insertion, with a mean average precision (mAP) of 0.75 or higher. Most of the equipment showed good accuracy of mAP 0.7 or higher, except for the suction device, suture material, and retractor. Conclusions: Scene annotation for the instrument and phases in THA using deep learning techniques may provide potentially useful tools for subsequent documentation, assessment of skills, and feedback.

Virtual biomechanical assessment of porous tantalum and custom triflange components in the treatment of patients with acetabular defects and pelvic discontinuity.

Aims: The aim of this study was to compare the biomechanical models of two frequently used techniques for reconstructing severe acetabular defects with pelvic discontinuity in revision total hip arthroplasty (THA) - the Trabecular Metal Acetabular Revision System (TMARS) and custom triflange acetabular components (CTACs) - using virtual modelling. Methods: Pre- and postoperative CT scans from ten patients who underwent revision with the TMARS for a Paprosky IIIB acetabular defect with pelvic discontinuity were retrospectively collated. Computer models of a CTAC implant were designed from the preoperative CT scans of these patients. Computer models of the TMARS reconstruction were segmented from postoperative CT scans using a semi-automated method. The amount of bone removed, the implant-bone apposition that was achieved, and the restoration of the centre of rotation of the hip were compared between all the actual TMARS and the virtual CTAC implants. Results: The median amount of bone removed for TMARS reconstructions was significantly greater than for CTAC implants (9.07 cm3 (interquartile range (IQR) 5.86 to 21.42) vs 1.16 cm3 (IQR 0.42 to 3.53) (p = 0.004). There was no significant difference between the median overall implant-bone apposition between TMARS reconstructions and CTAC implants (54.8 cm2 (IQR 28.2 to 82.3) vs 56.6 cm2 (IQR 40.6 to 69.7) (p = 0.683). However, there was significantly more implant-bone apposition within the residual acetabulum (45.2 cm2 (IQR 28.2 to 72.4) vs 25.5 cm2 (IQR 12.8 to 44.1) (p = 0.001) and conversely significantly less apposition with the outer cortex of the pelvis for TMARS implants compared with CTAC reconstructions (0 cm2 (IQR 0 to 13.1) vs 23.2 cm2 (IQR 16.4 to 30.6) (p = 0.009). The mean centre of rotation of the hip of TMARS reconstructions differed by a mean of 11.1 mm (3 to 28) compared with CTAC implants. Conclusion: In using TMARS, more bone is removed, thus achieving more implant-bone apposition within the residual acetabular bone. In CTAC implants, the amount of bone removed is minimal, while the implant-bone apposition is more evenly distributed between the residual acetabulum and the outer cortex of the pelvis. The differences suggest that these implants used to treat pelvic discontinuity might achieve short- and long-term stability through different biomechanical mechanisms.

Cost-effectiveness of decellularised bone allograft compared with fresh-frozen bone allograft for acetabular impaction bone grafting during a revision hip arthroplasty in the UK.

OBJECTIVES: Fresh-frozen allograft is the gold-standard bone graft material used during revision hip arthroplasty. However, new technology has been developed to manufacture decellularised bone with potentially better graft incorporation. As these grafts cost more to manufacture, the aim of this cost-effectiveness study was to estimate whether the potential health benefit of decellularised bone allograft outweighs their increased cost. STUDY DESIGN: A Markov model was constructed to estimate the costs and the quality-adjusted life years of impaction bone grafting during a revision hip arthroplasty. SETTING: This study took the perspective of the National Health Service in the UK. PARTICIPANTS: The Markov model includes patients undergoing a revision hip arthroplasty in the UK. INTERVENTION: Impaction bone grafting during a revision hip arthroplasty using either decellularised bone allograft or fresh-frozen allograft. MEASURES: Outcome measures included: total costs and quality-adjusted life years of both interventions over the lifetime of the model; and incremental cost-effectiveness ratios for both graft types, using base case parameters, univariate sensitivity analysis and probabilistic analysis. RESULTS: The incremental cost-effectiveness ratio for the base case model was found to be £270 059 per quality-adjusted life year. Univariate sensitivity analysis found that changing the discount rate, the decellularised bone graft cost, age of the patient cohort and the revision rate all had a significant effect on the incremental cost-effectiveness ratio. CONCLUSIONS: As there are no clinical studies of impaction bone grafting using a decellularised bone allograft, there is a high level of uncertainty around the costs of producing a decellularised bone allograft and the potential health benefits. However, if a decellularised bone graft was manufactured for £2887 and lowered the re-revision rate to less than 64 cases per year per 10 000 revision patients, then it would most likely be cost-effective compared with fresh-frozen allograft.

Custom-made implants for massive acetabular bone loss: accuracy with CT assessment.

BACKGROUND: Custom-made implants are a valid option in revision total hip arthroplasty to address massive acetabular bone loss. The aim of this study was to assess the accuracy of custom-made acetabular implants between preoperative planning and postoperative positioning using CT scans. METHODS: In a retrospective analysis, three patients who underwent an acetabular custom-made prosthesis were identified. The custom-made designs were planned through 3D CT analysis considering surgical points of attention. The accuracy of intended implants positioning was assessed by comparing pre- and postoperative CT analyzing the center of rotation (CoR), anteversion, inclination, screws, and implant surface in contact with the bone. RESULTS: The three cases presented satisfactory accuracy in positioning. A malpositioning in the third case was observed due to the posterization of the CoR of the implant of more than 10 mm. The other CoR vectors considered in the third patient and all vectors in the other two cases fall within 10 mm. All the cases were positioned with a difference of less than 10° of anteversion and inclination with respect to the planning. CONCLUSIONS: The current case series revealed promising accuracy in the positioning of custom-made acetabular prosthesis comparing the planned implant in preoperative CT with postoperative CT.

Acetabular Rim Disorders: Epidemiology, Etiology, Management, and Outcomes.

¼ Anatomic disorders of the acetabular rim are a common, correctable source of hip pain in younger patients.¼ Some common conditions of involving abnormal acetabular rim morphology include developmental dysplasia of the hip, pincer-type femoroacetabular impingement, acetabular protrusion, and acetabular retroversion.¼ Treatment option for these conditions were historically limited to open osteotomy and osteoplasty procedures; however, there is increasing use of arthroscopic intervention for these patients.¼ Arthroscopic intervention has demonstrated short-term success in a variety of focal acetabular rim disorders; however, further research is needed to determine the long-term outcomes of these procedures and their utility in more global pathology.

Outcomes of arthroscopy of the hip for femoroacetabular impingement based on intraoperative assessment using the Outerbridge classification.

Aims: Hip arthroscopy (HA) has become the treatment of choice for femoroacetabular impingement (FAI). However, less favourable outcomes following arthroscopic surgery are expected in patients with severe chondral lesions. The aim of this study was to assess the outcomes of HA in patients with FAI and associated chondral lesions, classified according to the Outerbridge system. Methods: A systematic search was performed on four databases. Studies which involved HA as the primary management of FAI and reported on chondral lesions as classified according to the Outerbridge classification were included. The study was registered on PROSPERO. Demographic data, patient-reported outcome measures (PROMs), complications, and rates of conversion to total hip arthroplasty (THA) were collected. Results: A total of 24 studies were included with a total of 3,198 patients (3,233 hips). Patients had significantly less improvement in PROMs if they had Outerbridge grade III and IV lesions (p = 0.012). Compared with microfracture, autologous matrix-induced chondrogenesis (AMIC) resulted in significantly reduced rates of conversion to THA (p = 0.042) and of revision arthroscopy (p = 0.038). Chondral repair procedures in these patients also did not significantly reduce the rates of conversion to THA (p = 0.931), or of revision arthroscopy (p = 0.218). However, compared with microfracture, AMIC significantly reduced the rates of conversion to THA (p = 0.001) and of revision arthroscopy (p = 0.011) in these patients. Those with Outerbridge grade III and IV lesions also had significantly increased rates of conversion to THA (p = 0.029) and of revision arthroscopy (p = 0.023) if they had associated lesions of the acetabulum and femoral head. Those who underwent labral debridement had a significantly increased rate of conversion to THA compared with those who underwent labral repair (p = 0.015). Conclusion: There is universal improvement in PROMs following HA in patients with FAI and associated chondral lesions. However, those with Outerbridge grade III and IV lesions had significantly less improvement in PROMs and a significantly increased rate of conversion to THA than those with Outerbridge grade I and II. This suggests that the outcome of HA in patients with FAI and severe articular cartilage damage may not be favourable.

Single-use versus reusable ancillaries for dual mobility cup in total hip replacement. A prospective randomized short-term safety and feasibility comparison.

BACKGROUND: Single-use (SU) ancillaries for cup preparation in total hip arthroplasty (THR) aim to reduce the costs of hip replacement surgery. These devices have been recently introduced, but their safety and feasibility have not been studied. Therefore, we performed a prospective randomized study aiming to assess the impact in our department of using these SU ancillaries versus standard reusable ancillaries for dual mobility THR regarding 1) the cost, 2) operative time, 3) quality of primary fixation. HYPOTHESIS: We hypothesized that the use of SU ancillaries for acetabular preparation would reduce maintenance costs, and so optimise the operating procedure, reduce the overall cost of surgery, save time, while maintaining the same quality of prosthesis fitting. METHOD: We conducted a randomised, controlled, open-label, two-arm, single-centre, prospective therapeutic trial with a medico-economic objective. Inclusions were made prospectively from patients hospitalised and surgically managed in our department for arthrosis over 18 years old treated with dual mobility THR. RESULTS: In the current study, 18/20 (90%) of the cases required the use of one SU reamer when using SU ancillaries. Only two cases (10%) required a second SU reamer (without SU failure regarding the acetabular implant) because there was too much subchondral bone left and not enough cancellous bone allowing correct cup fitting. We also found that the test implant supplied in the SU kit had a less secure press-fit than the reusable metal test implants. There was one of primary press-fit failure in the SU group requiring a different cup with additional screws. The estimated cost to the supplier per procedure was 20,105 euros using single-use reamers versus 26,666 euros using conventional ancillary kits, a saving of 6561 euros (p<0.001). For the healthcare institution, the median price per intervention on the differentiating points was 2648 euros versus 2580 euros, with no significant difference (p=0.297). The results show an average societal cost of 52,199 euros using single-use and 53,572 euros using reusable ancillary equipment, with a significant difference between the two groups (p<0.003). The average cost of Healthcare Risk Waste (HCRW) disposal in the SU group was 5.2 euros per intervention against 5.1 euros in the RU group, without significant difference (p=0.910). We found a similar result for the cost of disposal of non-HCRW waste per procedure: 0.37 euros in the SU group versus 0.34 in the RU group, without significant difference (p=0.345). CONCLUSION: SU ancillaries significantly reduce the table set up time and have the potential to facilitate time and cost savings but further research is needed in this direction. Our study shows that the daily workload, operating times, and the number of boxes of instruments to be sterilised are decreased. The associated environmental gain is significant. Nevertheless, the economic promise of these SU ancillaries is only partially supported in this trial owing to the small number of patients. Further work will be needed to obtain a more powerful medico-economic assessment of this promising ancillary product. LEVEL OF EVIDENCE: II; prospective randomized study.

Standard versus low-dose computed tomography for assessment of acetabular fracture reduction using novel step and gap measurement technique.

PURPOSE: Quality of reduction is of paramount importance after acetabular fracture and is best assessed on computed tomography (CT). A recently proposed measurement technique for assessment of step and gap displacement is reproducible but has not been validated. The purpose of this study is to validate a well-established measurement technique against known displacements and to determine if it can be used with low dose CT. METHODS: Posterior wall acetabular fractures were created in 8 cadaveric hips and fixed at known step and gap displacements. CT was performed at multiple radiation doses for each hip. Four surgeons measured step and gap displacement for each hip at all doses, and the measurements were compared to known values. RESULTS: There were no significant differences in measurements across surgeons, and all measurements were found to have positive agreement. Measurement error < 1.5 mm was present in 58% of gap measurements and 46% of step measurements. Only for step measurements at a dose of 120 kVp did we observe a statistically significant measurement error. There was a significant difference in step measurements made by those with greater and those with fewer years in practice. CONCLUSION: Our study suggests this technique is valid and accurate across all doses. This is important as it may reduce the amount of radiation exposure for patients with acetabular fractures.

Impact of three-dimensional printed planning in Paprosky III acetabular defects: a case-control and cost-comparison analysis.

PURPOSE: The main challenges in revision total hip arthroplasty (rTHA) are the treatment of the bone loss and the pre-operative planning. 3D-printed models may enhance pre-operative planning. The aim of the study is to compare the intra- and peri-operative results and costs for Paprosky type 3 rTHAs planned with 3D-printed models to ones accomplished with the conventional imaging techniques (X-rays and CT scan). METHODS: Seventy-two patients with Paprosky type 3 defect underwent rTHA between 2014 and 2021. Fifty-two patients were treated with standard planning and 20 were planned on 3D-printed models. Surgical time, intra-operative blood loss, number of transfused blood units, number of post-operative days of hospitalization, and use of acetabular rings were compared between the two groups. A costs comparison was also performed. RESULTS: The 3D-printed group showed reduced operative time (101.8 min (SD 27.7) vs. 146.1 min (SD 49.5), p < 0.001) and total days of hospitalization (9.3 days (SD 3.01) vs. 12.3 days (SD 6.01), p = 0.009). The cost of the procedures was significantly lower than the control group, with an adjusted difference of 4183 euros (p = 0.004). No significant differences were found for the number of total transfused blood units and blood loss and the number of acetabular rings. CONCLUSION: The use of 3D-printed models led to a meaningful cost saving. The 3D-printed pre-operative planning for complex rTHAs seems to be effective in reducing operating time, hospital stay and overall costs.

Acetabular Diameter Assessment and Three-Dimensional Simulation for Acetabular Reconstruction in Dysplastic Hips.

BACKGROUND: This study aimed to investigate the relationship between acetabular width, three-dimensional (3D) simulation, and surgical results in total hip arthroplasty patients who have developmental dysplasia of the hip (DDH). METHODS: This retrospective study included 216 DDH cases. Inner and outer acetabular width (OAW) was measured at the plane passing through the center of acetabular fossa. 3D simulation and 2D standard templating were performed. The actual cup size and the use of augments during surgery were recorded. Association among the indices and their distribution in different types of DDH were analyzed. RESULTS: A difference of 13 to 14 millimeters (mm) was found between the inner acetabular width and actual cup size used in type II, III, and IV cases, while the difference was 0.2 to 3.6 mm for OAW. The accuracy of 2D templating and 3D simulation in predicting cup size was comparable in Crowe type I (86.5 versus 76%, P = .075), type II (72.7 versus 51.5%, P = .127), and type III (93.3 versus 66.7%, P = .169). The 3D simulation was significantly more accurate in Crowe type IV (89.1% versus 60.9%, P = .001). Augments and bone grafts were significantly more commonly used in type II (25%) than in the other types (0 to 6.5%). CONCLUSION: OAW more accurately predicted actual cup size than inner acetabular width. The supero-lateral acetabular bone defects in type II cases require additional attention. Compared with 2D templating, 3D simulation is more accurate in predicting actual cup size in dysplastic hips with severe deformity and may be recommended in these selected cases, especially for Crowe IV patients.

Influence of kinematics of the lumbopelvic complex in hip arthroplasty dislocation: from assessment to recommendations.

INTRODUCTION: In total hip arthroplasty (THA), misplacement of the implant can provide instability. Adequate orientation of the acetabular cup is a challenge due to variations in inter-individual anatomy and kinematics of the pelvis in everyday life. The aim of this study was to characterize the kinematic factors influencing the risk of dislocation in order to give recommendations for optimal placement of the cup. We hypothesized that the lack of pelvic adaptation would influence the risk of prosthetic instability and motivate adapted. MATERIALS AND METHODS: Eighty patients with primary unilateral THA were included in a matched case-control study. Seventy-four patients were divided into two groups: group 1 (G1) consisting of patients with postoperative THA dislocation (37 patients) and group 2 (G2), without episodes of dislocation within two years postoperatively (37 patients). In both groups, spino-pelvic parameters and cup orientation were measured in standing and sitting positions with EOS® X-ray imaging and compared to each other between 12 and 24 months post-operatively. RESULTS: No significant difference between the two groups was found for static parameters. In a sitting position, a lack of pelvic retroversion with a significant lower variation in sacral slope was observed in group 1 (8.0° ± 9.3 for G1 versus 14.7° ± 6.2 for G2, p < 0.01). Twenty-two (59%) patients with THA instability had sacral slope variations of less than 10° versus eight (21% of patients) with stable THA (p < 0.01). Cup orientation in the Lewinnek safe zone was not significantly different (59% vs 67%, p = 0.62), and the spino-pelvic parameters and cup orientation measured did not change between the standing and sitting positions. However, only 14 (37%) cups in G1 were in the functional safe zone versus 24 (67%) in G2 (p = 0.03). CONCLUSION: Static parameters of the sagittal spinopelvic balance have a low predictive value for prosthetic instability. Dynamic analysis is essential. Kinematic parameters must be taken into account in determining the ideal position of the cup or stem. Stiffness with locked standing or sitting pelvis must be integrated in order to determine a personalized safe zone. LEVEL OF EVIDENCE: Level III (matched case-control study).

APP-guided assessment of acetabular defects in hip revision arthroplasty: a structured approach to a complex situation.

INTRODUCTION: Acetabular defect recognition and classification remains a challenging field of practice for orthopedic surgeons. Recently, the Acetabular Defect Classification (ADC) has been introduced to provide a reliable, reproducible and intuitive classification system. In order to improve ease of use and efficiency of the ADC, a browser-based application has been created. We hypothesized that the ADC application can improve rating performance of non-specialists (medical students) to achieve good inter- and intra-rater agreement and will compare favorable to the results of specialists (experienced surgeons) without the help of the application. MATERIALS AND METHODS: The ADC is based on the integrity of the acetabular rim and the supporting structures. It consists of four main types of defects ascending in severity. These defects are further subdivided in A-C, narrowing down defect location. 80 randomized radiographs were graded according to ADC by three non-specialists (medical students) with help of the ADC application and by three specialists (orthopedic surgeons) without help of the application to evaluate the difference in inter-rater agreement between groups. To account for intra-rater agreement, the rating process was repeated after a reasonable wash-out period. RESULTS: Inter-rater and intra-rater agreement within the non-specialist group rated lower when compared to the specialist group while still falling into the good agreement range. The student group presented with k values of 0.61 for inter-rater agreement and 0.68 for intra-rater agreement, while the surgeon group displayed k values of 0.72 for inter-rater agreement and 0.83 for intra-rater agreement. CONCLUSION: The app-guided assessment of acetabular defects offers a promising innovative approach to simplify complex situations. It makes the challenging field of acetabular revision arthroplasty more approachable especially for less experienced surgeons and offers insight and guidance in the planning stage as well as intra-operative setting.

Editorial Commentary: Routine Preoperative Magnetic Resonance Imaging for Hip Arthroscopy Is Wasting Health Care Dollars and Delaying Surgical Intervention: Decision Making Should Be at the Discretion of the Health Care Provider Not Mandated by Health Care Insurers.

Making an accurate preoperative diagnosis is critical to optimizing outcomes after hip arthroscopy. A detailed history, thorough physical examination, imaging studies, and diagnostic injections must all be considered in the decision-making process. In today's health care climate, it is imperative to obtain essential and indicated preoperative information while being mindful of health care dollars. Magnetic resonance imaging (MRI) of the hip has been shown to be a highly sensitive modality for hip and pelvis disorders. However, it is critical to recognize that acetabular labral tears and other hip pathology are highly prevalent in an asymptomatic young adult population. There are certainly situations when an MRI should be obtained (suspected arthritic symptoms, avascular necrosis, synovial disorders, uncommon osseous tumors); however, these patients generally present with atypical symptoms. In addition, obtaining an MRI can delay surgical intervention, which has been shown to lead to inferior outcomes in prior studies. MRI is not imperative when patients present with typical intermittent, deep anterior, lateral, groin pain with prolonged sitting, twisting and pivoting, and transitioning from sitting to standing. The typical physical examination includes positive hip impingement testing (FADIR / anterior impingement test) that recreates the patients presenting complaints. Appropriate imaging includes plain radiographs revealing adequate acetabular coverage (not significantly dysplastic) or acetabular overcoverage (pincer-type femoracetabular impingement), cam-type femoracetabular impingement, and well-maintained joint space on all views, including a false profile radiograph to further evaluate the anterior joint space. Finally, a diagnostic injection can be invaluable to further confirm the hip joint proper as the source of pain. If all of the above criteria are met, I strongly believe an MRI is unlikely to alter the surgical decision-making process. In the end, the treating clinician should determine when an MRI is necessary based on the presenting symptoms and examination, rather than insurers applying a blanket requirement for preauthorization. This physician autonomy would ultimately lead to more efficient and cost-effective patient care. Medicine is an art, and unjustified handcuffing of the artist without evidence could result in inferior results.

Low interobserver and intraobserver reliability using the Matta radiographic system for intraoperative assessment of reduction following acetabular ORIF.

INTRODUCTION: The system described by Matta for rating acetabular fracture quality of reduction following ORIF has been used extensively throughout the literature. However, the reliability of this system remains to be validated. We sought to determine the interobserver and intraobserver reliability of this system when used by fellowship-trained pelvic and acetabular surgeons to evaluate intraoperative fluoroscopy. METHODS: This is a retrospective evaluation of a prospectively collected acetabular fracture database at an academic level I trauma center. The quality of reduction of all acetabular fractures treated with open reduction internal fixation (ORIF) between May 2013 and December 2015 was assessed using three standard intraoperative fluoroscopic views (anteroposterior and two 45˚ oblique Judets). Displacement of ≤1 mm was considered to be an anatomic reduction, 2-3 mm imperfect, and >3 mm poor according to the system described by Matta. A total of 107 acetabular fractures treated with ORIF with complete intraoperative fluoroscopic images during that time period were available for review. Acetabular fracture reductions were reviewed by the operative surgeon at the time of surgery and subsequently reviewed by two fellowship-trained pelvic and acetabular surgeons. All reduction assessments were performed in a blinded fashion. The primary outcome measure was interobserver reliability for assessing reduction quality. This was evaluated using a weighted kappa (κw) statistic between each evaluator and the operative surgeon and a generalized kappa (κg) for all 3 surgeons. After a 6-week "washout interval," the surgeons reviewed the images again and intraobserver agreement was calculated using a weighted kappa statistic. RESULTS: Interobserver reliability based on the initial assessment was low (κg = 0.09); however, did slightly improve with the second assessment to fair (κg = 0.24). Intraobserver reliability ranged from slight (κw = 0.20) to moderate (κw = 0.53) among the surgeons. DISCUSSION: Low interobserver and intraobserver reliability was found when quality of reduction was assessed with intraoperative fluoroscopic images by the operative and two other pelvic and acetabular surgeons using the Matta system. Given the importance of an anatomic reduction on functional and radiographic outcomes, an accurate and reliable system for assessing intraoperative quality of reduction is essential.

Precision of low-dose CT-based micromotion analysis technique for the assessment of early acetabular cup migration compared with gold standard RSA: a prospective study of 30 patients up to 1 year.

BACKGROUND AND PURPOSE: Computed tomography micromotion analysis (CTMA) can be used to determine implant micro-movements using low-dose CT scans. By using CTMA, a non-invasive measurement of joint implant movement is enabled. We evaluated the precision of CTMA in measuring early cup migration. Standard marker-based radiostereometric analysis (RSA) was used as reference. We hypothesised that CTMA can be used as an alternative to RSA in assessing implant micromotions. PATIENTS AND METHODS: We included 30 patients undergoing total hip arthroplasty (THA). Acetabular cup migration at 1 year was measured with RSA and CTMA. To determine the precision of both methods, 20 double examinations (postoperatively) with repositioning of the patients were performed. The precision was calculated from zero by assuming that there was no motion of the prosthesis between the 2 examinations. RESULTS: The precision of RSA ranged from 0.06 to 0.15 mm for translations and 0.21° to 0.63° for rotations. Corresponding values for CTMA were 0.06 to 0.13 mm and 0.23° to 0.35°. A good level of agreement was found between the methods regarding cup migration and rotation at 1 year. INTERPRETATION: The precision of CTMA in measuring acetabular cup migration and rotation is comparable to marker-based RSA. CTMA could possibly thus be used as an alternative method to detect early implant migration.

Radiological and Functional Assessment of Treatment Outcomes in Patients after Open Reduction with Internal Fixation (ORIF) of Acetabular Fractures.

(1) Fracture of the pelvis usually happens in young men and results from high-energy trauma. It generates high social and economic costs and results in further health problems. It is therefore important to assess long-term treatment results. (2) The study (NCT04902209) involved 31 patients (mean age 43.6 ± 14.8 years). We conducted fixation assessment on the basis of radiographs and CT scans and functional assessment based on functional scales. (3) We observed more degenerative changes in the less precise reconstruction of the acetabulum (p = 0.075). We did not find statistically significant relationships between the area of surgical approach, the gravity of fracture, and the development of degenerative changes. We did not find statistically significant relationships between patients' functional states and the type of surgical approach or the complexity of the fracture. We found a positive correlation between the time of surgical treatment and patients' functional state (p = 0.04). Patients whose joint surfaces were reconstructed anatomically had significantly higher scores in functional scales (HHS p = 0.05, Merle p = 0.03). (4) Patients after surgical fixation of the acetabulum have low functional abilities. The quality of reconstruction of the loaded surface as well as the length of time post-surgery seems to be essential for the patients' functional state.

Assessment of deep vein thrombosis using routine pre- and postoperative duplex Doppler ultrasound in patients with pelvic trauma : a prospective study.

AIMS: The aims of this study were to assess the pre- and postoperative incidence of deep vein thrombosis (DVT) using routine duplex Doppler ultrasound (DUS), to assess the incidence of pulmonary embolism (PE) using CT angiography, and to identify the factors that predict postoperative DVT in patients with a pelvic and/or acetabular fracture. METHODS: All patients treated surgically for a pelvic and/or acetabular fracture between October 2016 and January 2020 were enrolled into this prospective single-centre study. The demographic, medical, and surgical details of the patients were recorded. DVT screening of the lower limbs was routinely performed using DUS before and at six to ten days after surgery. CT angiography was used in patients who were suspected of having PE. Age-adjusted univariate and stepwise multiple logistic regression analysis were used to determine the association between explanatory variables and postoperative DVT. RESULTS: A total of 191 patients were included. A DVT was found preoperatively in 12 patients (6.3%), of which six were proximal. A postoperative DVT was found in 42 patients (22%), of which 27 were proximal. Eight patients (4.2%) had a PE, which was secondary to a DVT in three. None of the 12 patients in whom a vena cava filter was implanted prophylactically had a PE. Multivariate logistic regression analysis indicated that the association with the need for spinal surgery (odds ratio (OR) 19.78 (95% confidence interval (CI) 1.12 to 348.08); p = 0.041), intramedullary nailing of a long bone fracture (OR 4.44 (95% CI 1.05 to 18.86); p = 0.043), an operating time > two hours (OR 3.28 (95% CI 1.09 to 9.88); p = 0.035), and additional trauma surgery (OR 3.1 (95% CI 1.03 to 9.45); p = 0.045) were statistically the most relevant independent predictors of a postoperative DVT. CONCLUSION: The acknowledgement of the risk factors for the development of a DVT and their weight is crucial to set a threshold for the index of suspicion for this diagnosis by medical staff. We suggest the routine use of the DUS screening for DVT in patients with a pelvic and/or acetabular fracture before and six to ten days after surgery. Cite this article: Bone Joint J 2022;104-B(2):283-289.

Assessment of the endoprosthesis offset in a dysplastic coxarthrosis.

Incorrectly developed acetabulum and subluxated hip joint may cause many problems for proper implantation of endoprosthesis. The aim of this work is to assess the radiological results of offset restoration and selection of endoprosthesis implant in a dysplastic hip joint. The study group consisted of patients who had a surgery in the period between 2016 and 2018. All of them had a cementless total hip endoprosthesis. The group consisted of 91 patients (96 hip joints), with an average age of 42 years (31-47 years). 55 left and 41 right hip joints. 70 females and 21 males. The control group consisted of patients who were not diagnosed with hip joint dysplasia. The control group consisted of 70 patients (70 hip joints), with an average age of 35 years (19-55 years). 53 females and 17 males. The radiographic assessment included the measuring of medialization and distalization which describe the offset of hip joint. The joint decentration was classified according to Crowe. Based on radiographic measurements we have achieved statistically significant (p<0.05) changes in medialization and distalization parameters. We have not noticed a statistically significant difference for medialization parameter (p=0.8259) after a surgery when compared to the control group. For all patients we have achieved a restoration of correct offset in the horizontal plane. The main idea behind endoprosthesis in a dysplastic coxarthosis is the implantation of endoprosthesis cup in an anatomically correct location. Small screw- in cup and conical stem offer great possibility of restoring correct offset of a dysplastic hip joint.

Radiographic assessment of the dynasty biofoam acetabular component with a minimum 2 years follow-up.

INTRODUCTION: Acetabular components utilising novel ultraporous metal matrices have been recently introduced into clinical practice with improved interference fit, decreased stress shielding, and hope for more reliable osseointegration. 1 such example is the Dynasty Biofoam cup, which has been in clinical use for over a decade but has few reports documenting its clinical and radiographic performance. METHODS: A single-centre retrospective study was performed evaluating 96 Dynasty Biofoam acetabular components implanted between March 2010 and August 2014 with minimum 2-year radiographic follow-up. Patients that received components for revision surgery or that had early complications postoperatively (femur fracture, prosthetic infection) were excluded. Biofoam patients were compared to 96 patients that received the Trident PSL acetabular component and were matched for age, gender, and BMI. Patient reported outcomes, component position and radiographic features of cup loosening, including radiolucent lines and sclerosis were compared among groups. RESULTS: Patient-reported outcomes at 2 years were similar among groups. Cup anteversion was similar but inclination was significantly greater in the Biofoam group (p = 0.006). A significantly greater number of Biofoam components exhibited 2-zone (27.2%) and 3-zone (12.0%) radiolucencies compared to 0% of the Trident shells (p < 0.05). 2 Biofoam cups were revised for aseptic loosening compared to no Trident cups (p = 0.49). DISCUSSION: Despite adequate implant survivorship, over a quarter of Biofoam cups had 2 or more radiolucent zones in early follow-up. Longer follow-up is needed to determine if the aseptic revision rate for this cup will increase.

Cost-Effectiveness of Preoperative Spinal Imaging Before Total Hip Arthroplasty.

BACKGROUND: The risk of instability, dislocation, and revision following total hip arthroplasty (THA) is increased in patients with abnormal spinopelvic mobility. Seated and standing lateral lumbar spine imaging can identify patients with stiff/hypermobile spine (SHS) to guide interventions such as changes in acetabular cup placement or use of a dual-mobility hip construct aimed at reducing dislocation risk. METHODS: A Markov decision model was created to compare routine preoperative spinal imaging (PSI) to no screening in patients with and without SHS. Screened patients with SHS were assumed to receive dual-mobility hardware while those without SHS and nonscreened patients were assumed to receive conventional THA. Cost-effectiveness was determined by estimating the incremental cost-effectiveness ratio. Effectiveness measured as quality-adjusted life years (QALYs), with $100,000 per additional QALY as the threshold for cost-effectiveness. Sensitivity analyses were performed to determine the robustness of the base-case result. RESULTS: The screening strategy with PSI had a lifetime cost of $12,515 and QALY gains of 16.91 compared with no-screening ($13,331 and 16.77). The PSI strategy reached cost-effectiveness at 5 years and was dominant (ie, less costly and more effective) at 11 years following THA. In sensitivity analyses, PSI remained the dominant strategy if prevalence of SHS was >1.9%, the cost of PSI was <$925, and the cost of dual-mobility hardware exceeded the cost of conventional hardware by <$2850. CONCLUSION: Screening patients for SHS prior to THA with PSI is both less costly and more effective and should be considered as part of standard presurgical workup.