761 cases in 613 patients with minimal two years follow-up had both metal ion levels and quality pelvis X-ray identified in our database and are included in this study. The UCLA activity score, femoral shaft angle, body mass index, weight, American Society of Anesthesiologists (ASA) score, combined range of motion (CROM), diagnosis, age, implant brand, gender, AIA, bearing size, and duration of implantation were analyzed to determine the potential risk factors for elevated metal ion levels with use of uni- and multi-variable logistic regression models. A safe zone for hip resurfacing (RAIL: Relative Acetabular Inclination Limit) was calculated based on implant size and AIA on AP pelvis X-ray. For AIA below the RAIL, there were no adverse wear failures or dislocations, and only 1% of cases with ion levels above 10 μg/L. We have not found a lower limit of AIA where failures occurred. Other than high inclination angle and small bearing size, female gender was the only other factor that correlated with high ion levels in the multivariate analysis. We have described the robust “safe zone” for
Introduction: Metal-on-metal-hip-resurfacing-arthroplasty (MoMHRA) has been associated with the development of inflammatory pseudotumours(IP), especially in females. IPs have been linked to wear debris, which can be related to metal-ion blood levels.
Introduction. Pelvic flexion and extension in different body positions can affect acetabular orientation after total hip arthroplasty, and this may predispose patients to dislocation. The purpose of this study was to evaluate functional
Appropriate acetabular component placement has been proposed for prevention of postoperative dislocation in total hip arthroplasty (THA). Manual placements often cause outliers in spite of attempts to insert the component within the intended safe zone; therefore, some surgeons routinely evaluate intraoperative pelvic radiographs to exclude excessive acetabular component malposition. However, their evaluation is often ambiguous in case of the tilted or rotated pelvic position. The purpose of this study was to develop the computational analysis to digitalize the acetabular component orientation regardless of the pelvic tilt or rotation. Intraoperative pelvic radiographs of 50 patients who underwent THA were collected retrospectively. The 3D pelvic bone model and the acetabular component were image-matched to the intraoperative pelvic radiograph. The radiological anteversion (RA) and radiological inclination (RI) of the acetabular component were calculated and those measurement errors from the postoperative CT data were compared relative to those of the 2D measurements. In addition, the intra- and interobserver differences of the image-matching analysis were evaluated.Aims
Methods
Introduction.
For the whole cohort, there was no significant difference in ion levels (Cr: p=0.092. Co=0.075) between cups positioned within Z3 (n=58) versus those outside (n=46 mean). Male patients with cups within Z3 (n=27) had lower ion levels in comparison to those outside Z3, which were significantly lower for Co (p=0.049) but not Cr (p=0.084). Female patients had similar levels within and out of Z3 for both ions (Cr: p=0.83, Co: p=0.84). However, patients with cups within Z1 (n=13) had significantly lower Co (p=0.005) and Cr (p=0.001) than those outside Z1 (n=95). Interestingly, Co levels were significantly lower in Z1 (n=13) in comparison to Z2 (n=33) (p=0.048) but Cr levels were not different (p=0.06).
Aims. Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA. Methods. This prospective randomized controlled trial (RCT) included 60 patients with symptomatic hip osteoarthritis undergoing conventional THA (CO THA) versus robotic arm-assisted THA (RO THA). Patients in both arms underwent pre- and postoperative CT scans, and a patient-specific plan was created using the robotic software. The COR, combined offset, acetabular orientation, and leg length discrepancy were measured on the pre- and postoperative CT scanogram at six weeks following surgery. Results. There were no significant differences for any of the baseline characteristics including spinopelvic mobility. The absolute error for achieving the planned horizontal COR was median 1.4 mm (interquartile range (IQR) 0.87 to 3.42) in RO THA versus 4.3 mm (IQR 3 to 6.8; p < 0.001); vertical COR mean 0.91 mm (SD 0.73) in RO THA versus 2.3 mm (SD 1.3; p < 0.001); and combined offset median 2 mm (IQR 0.97 to 5.45) in RO THA versus 3.9 mm (IQR 2 to 7.9; p = 0.019). Improved accuracy was observed with RO THA in achieving the desired
Aims. Acetabular edge-loading was a cause of increased wear rates in metal-on-metal hip arthroplasties, ultimately contributing to their failure. Although such wear patterns have been regularly reported in retrieval analyses, this study aimed to determine their in vivo location and investigate their relationship with
Abstract. Optimal
Abstract. Background. Optimal
In 2021, Vigdorchik et al. published a large multicentre study validating their simple Hip-Spine Classification for determining patient-specific
Aims. The complex relationship between
Aims. The aims of this study were to determine the change in the sagittal alignment of the pelvis and the associated impact on
Aims. Dislocation remains a leading cause of failure following revision total hip arthroplasty (THA). While dual-mobility (DM) bearings have been shown to mitigate this risk, options are limited when retaining or implanting an uncemented shell without modular DM options. In these circumstances, a monoblock DM cup, designed for cementing, can be cemented into an uncemented acetabular shell. The goal of this study was to describe the implant survival, complications, and radiological outcomes of this construct. Methods. We identified 64 patients (65 hips) who had a single-design cemented DM cup cemented into an uncemented acetabular shell during revision THA between 2018 and 2020 at our institution. Cups were cemented into either uncemented cups designed for liner cementing (n = 48; 74%) or retained (n = 17; 26%) acetabular components. Median outer head diameter was 42 mm. Mean age was 69 years (SD 11), mean BMI was 32 kg/m. 2. (SD 8), and 52% (n = 34) were female. Survival was assessed using Kaplan-Meier methods. Mean follow-up was two years (SD 0.97). Results. There were nine cemented DM cup revisions: three for periprosthetic joint infection, three for acetabular aseptic loosening from bone, two for dislocation, and one for a broken cup-cage construct. The two-year survivals free of aseptic DM revision and dislocation were both 92%. There were five postoperative dislocations, all in patients with prior dislocation or abductor deficiency. On radiological review, the DM cup remained well-fixed at the cemented interface in all but one case. Conclusion. While dislocation was not eliminated in this series of complex revision THAs, this technique allowed for maximization of femoral head diameter and optimization of effective
Aims. Posterior tilt of the pelvis with sitting provides biological
acetabular opening. Our goal was to study the post-operative interaction
of skeletal mobility and sagittal
Introduction. The direct anterior approach (DAA) for total hip arthroplasty (THA) has gained popularity in recent years. Potential advantages over other surgical approaches include less postoperative pain, fewer postoperative precautions, and quicker early recovery. It is most commonly performed in the supine position with traction tables or table mounted bone hooks to facilitate exposure. In this study, we describe a reproducible surgical technique for DAA THA in the lateral decubitus position with use of standard THA equipment and report on our results and learning curve. Methods. A prospectively collected hip repository was queried for all primary THA DAA performed in the lateral position by a single surgeon over a 4-year period from the surgeon's first case utilizing the technique. Retrospective chart review was performed to identify complications and revisions. Modified Harris Hip Score (mHHS) was collected pre-operatively and again at 1-year post-operative. Radiographic parameters including were measured on the 1-year postoperative radiographs. Results. Three hundred forty-one hips were identified in patients over 18 years of age with 337 hips meeting our inclusion/exclusion criteria. A total of 257 hips (76%) had a minimum of 1-year follow-up. 212 of 225 hips (94%) with available mHHS data achieved MCID, defined as mHHS change of > 8. Mean surgical time was 88 ± 16 minutes. Radiographic evaluation demonstrated reproducible results with mean radiographic side to side leg length discrepancy of 2.6 ± 5.9mm and femoral offset difference of 0.2 ± 4.9mm. Among patients with adequate postoperative radiographs, 234 of 243 (96%) had
Evidence supporting the use of virtual reality (VR) training in orthopaedic procedures is rapidly growing. However, the impact of the timing of delivery of this training is yet to be tested. We aimed to investigate whether spaced VR training is more effective than massed VR training. 24 medical students with no hip arthroplasty experience were randomised to learning the direct anterior approach total hip arthroplasty using the same VR simulation, training either once-weekly or once-daily for four sessions. Participants underwent a baseline physical world assessment on a saw bone pelvis. The VR program recorded procedural errors, time, assistive prompts required and hand path length across four sessions. The VR and physical world assessments were repeated at one-week, one-month, and 3 months after the last training session. Baseline characteristics between the groups were comparable (p > 0.05). The daily group demonstrated faster skills acquisition, reducing the median ± IQR number of procedural errors from 68 ± 67.05 (session one) to 7 ± 9.75 (session four), compared to the weekly group's improvement from 63 ± 27 (session one) to 13 ± 15.75 (session four), p < 0.001. The weekly group error count plateaued remaining at 14 ± 6.75 at one-week, 16.50 ± 16.25 at one-month and 26.45 ± 22 at 3-months, p < 0.05. However, the daily group showed poorer retention with error counts rising to 16 ± 12.25 at one-week, 17.50 ± 23 at one-month and 41.45 ± 26 at 3-months, p<0.01. A similar effect was noted for the number of assistive prompts required, procedural time and hand path length. In the real-world assessment, both groups significantly improved their
Background. The aim of this study was to determine the change in standing pelvic sagittal alignment and associated impact on functional
Acetabular cup positioning remains a real challenge and component malpositioning after total hip arthroplasty (THA) can lead to increased rates of dislocation and wear. It is a common cause for revision THA. A novel 3D imageless mini-optical navigation system was used during THA to provide accurate, intraoperative, real-time, and non-fluoroscopic data including component positioning to the surgeon. This retrospective comparative single surgeon and single approach study examined
There remains confusion in the literature with regard to the spinopelvic relationship, and its contribution to ideal
Acetabular implant position is important for the stability, function, and long-term wear properties of a total hip arthroplasty (THA). Prior studies of acetabular implant positioning have demonstrated a high percentage of outliers, even in experienced hip surgeons, when conventional instruments are used. Computer navigation is an attractive tool for use in (THA, as it has been shown to improve the precision of acetabular component placement and reduce the incidence of outliers. However, computer navigation with imageless, large-console systems is costly and often interrupts the surgeon's workflow, and thus, has not been widely adopted. Another method to improve
Background:. Numerous studies have reported the importance of
Highly crosslinked polyethylene (HXLPE) 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 in its second decade of service are still scant. The aim of this study was to 1. Determine the long term clinical and radiological results and 2. Investigate what factors affect wear rates using a metal-on-HXLPE bearing articulation. 55 THA's using a single brand of HXLPE liner, cementless cup and 28mm hip ball were performed in 44 patients. Age, sex, and 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 16.9 years (range 15.0–20.1 +/− 1.1 years). Osteolysis was not present in the latest follow up radiographs. Median linear and volumetric wear rate was 0.035mm/year (95% CI 0.031–0.047) and 7.12mm. 3. /year (95% CI 6.92–17.25) respectively.
Background. Supine positioning during direct anterior approach total hip arthroplasty (DAA THA) facilitates use of fluoroscopy, which has been shown to improve
Aims. Spinopelvic mobility plays an important role in functional
Abstract. Objectives. Non-technical skills including teamwork play a pivotal role in surgical outcomes. Virtual reality is effective at improving technical skills, however there is a paucity of evidence on team-based virtual reality (VR) training. This study aimed to assess if multiplayer virtual reality training was superior to solo training for acquisition of both technical and non-technical skills in learning the complex anterior approach total hip arthroplasty operation. Methods. 10 novice surgeons and 10 novice scrub nurses, were randomised to solo or team virtual reality training to perform anterior approach total hip arthroplasty. Solo participants trained with virtual avatar counterparts, whilst teams trained in pairs (surgeon and scrub nurse). Both groups underwent 5 VR training sessions over 6 weeks. Then, they underwent a real-life assessment in which they performed AA-THA on a high-fidelity model with real equipment in a simulated operating theatre. Teams performed together and solo participants were randomly paired up with a solo player of the opposite role. Videos of the assessment were marked by two blinded expert assessors. Outcomes were procedure time, procedural errors from an expert pre-defined protocol and
Abstract. Objectives. Evidence supporting the use of immersive virtual reality (iVR) training in orthopaedic procedures is rapidly growing. However, the impact of the timing of delivery of this training is yet to be tested. This study investigated whether spaced iVR training is more effective than massed iVR training for novices learning hip arthroplasty. Methods. 24 medical students with no hip arthroplasty experience were randomised to learning total hip arthroplasty using the same iVR simulation training either once-weekly or once-daily for four sessions. Participants underwent a baseline physical world assessment to orientate an acetabular component on a saw bone pelvis, and a baseline knowledge test. In iVR, we recorded procedural errors, time, numbers of prompts required and path lengths of the hands and head across 4 sessions. To assess skill retention, the iVR and baseline physical world assessments were repeated at one-week and one-month. Results. Baseline characteristics between the groups were comparable (p > 0.05). The daily group demonstrated faster skills acquisition, reducing the mean number of procedural errors from 76.8±37.5 (S1) to 11.1±10.1 (S4), compared to the weekly group improvement from 71.1±19.1 (S1) to 17.2±10.6 (S4), p < 0.001. The weekly group error count plateaued remaining at 16±6.7 at 1-week and 17.5±8.5 at one-month, the daily group however, showed poor retention with error counts rising to 17.8±10.5 at 1 week and becoming higher than the weekly group at one-month to (23.2±13.0 vs 17.5±10.5). A similar effect was noted for procedural time and the number of assistive prompts. In the real-world assessment, both groups significantly improved the accuracy of their
Introduction.
Acetabular implant position is important for the stability, function, and long-term wear properties of a total hip arthroplasty (THA). Prior studies of acetabular implant positioning have demonstrated a high percentage of outliers, even in experienced hip surgeons, when conventional instruments are used. Computer navigation is an attractive tool for use in THA, as it has been shown to improve the precision of acetabular component placement and reduce the incidence of outliers. However, computer navigation with imageless, large-console systems is costly and often interrupts the surgeon's workflow, and thus, has not been widely adopted. Another method to improve
Aims. The aims of this study were to determine the change in pelvic sagittal alignment before, during, and after total hip arthroplasty (THA) undertaken with the patient in the lateral decubitus position, and to determine the impact of these changes on
The purpose of this study is to assess the accuracy of component positioning and incidence of peri-operative and 90-day post-operative complications following robotic arm-assisted and conventional total hip arthroplasty (THA). Three groups of patients were analyzed for this study: those that underwent conventional THA performed by Surgeon 1, conventional THA performed by Surgeon 2, or robotic arm-assisted THA performed by Surgeon 2. All patients underwent primary uncemented THA via a posterior approach. Patient characteristics, intra-operative data, and 90-day post-operative complications were collected. Post-operative standing pelvic radiographs were utilized to measure acetabular position and to identify post-operative complications.
Introduction. The longevity of total hip arthroplasty (THA) is dependent on
Introduction. Total hip arthroplasty is considered to be one of the most successful orthopaedic interventions.
Acetabular implant position is important for the stability, function, and long-term wear properties of a total hip arthroplasty (THA). Prior studies of acetabular implant positioning have demonstrated a high percentage of outliers, even for experienced hip surgeons, when conventional instruments are used. Computer navigation is an attractive tool for use in THA, as it has been shown to improve the precision of acetabular component placement and reduce the incidence of outliers. However, computer navigation with imageless, large-console systems is costly and often interrupts the surgeon's workflow, and thus has not been widely adopted. Another method to improve
Problem. Total hip replacement (THA) is among the most common and highest total spend elective operations in the United States. However, up to 7% of patients have 90-day complications after surgery, most frequently joint dislocation that is related to poor
Orientation of the native acetabular plane as defined by the transverse acetabular ligament (TAL) and the posterior labrum was measured intra-operatively using computer-assisted navigation in 39 hips. In order to assess the influence of alignment on impingement, the range of movement was calculated for that defined by the TAL and the posterior labrum and compared with a standard
Objectives. The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual total hip arthroplasty (THA) versus robotic-arm assisted THA. Secondary objectives were to determine differences between these treatment techniques for THA in achieving the planned combined offset, component inclination, component version, and leg-length correction. Materials and Methods. This prospective cohort study included 50 patients undergoing conventional manual THA and 25 patients receiving robotic-arm assisted THA. Patients undergoing conventional manual THA and robotic-arm assisted THA were well matched for age (mean age, 69.4 years (. sd. 5.2) vs 67.5 years (. sd. 5.8) (p = 0.25); body mass index (27.4 kg/m. 2. (. sd. 2.1) vs 26.9 kg/m. 2. (. sd. 2.2); p = 0.39); and laterality of surgery (right = 28, left = 22 vs right = 12, left = 13; p = 0.78). All operative procedures were undertaken by a single surgeon using the posterior approach. Two independent blinded observers recorded all radiological outcomes of interest using plain radiographs. Results. The correlation coefficient was 0.92 (95% confidence interval (CI) 0.88 to 0.95) for intraobserver agreement and 0.88 (95% CI 0.82 to 0.94) for interobserver agreement in all study outcomes. Robotic THA was associated with improved accuracy in restoring the native horizontal (p < 0.001) and vertical (p < 0.001) centres of rotation, and improved preservation of the patient’s native combined offset (p < 0.001) compared with conventional THA. Robotic THA improved accuracy in positioning of the acetabular component within the combined safe zones of inclination and anteversion described by Lewinnek et al (p = 0.02) and Callanan et al (p = 0.01) compared with conventional THA. There was no difference between the two treatment groups in achieving the planned leg-length correction (p = 0.10). Conclusion. Robotic-arm assisted THA was associated with improved accuracy in restoring the native centre of rotation, better preservation of the combined offset, and more precise
Minimally invasive total hip replacement surgery not only decreases the number of visual cues necessary for proper
Background. Acetabulum positioning affects dislocation rates, component impingement, bearing surface wear rates, and need for revision surgery. Novel techniques purport to improve the accuracy and precision of
Aims. The aim of this study was to determine whether there is a difference
in the rate of wear between
Total hip replacement is among the most successful interventions in medicine and has been termed “The Operation of the Century”. Most major problems have been solved including femoral fixation, acetabular fixation, and wear. With a success rate of over 95% at 10 years in both hip and knee arthroplasty in a number of studies, the question remains as to whether the current status quo is optimal or acceptable. The literature, however, reports are from centers that represent optimised results and registry data, including the Medicare database, indicates that substantial short-term problems persist. The major issue is the variability in the performance of the procedure. The inability to consistently position components, particularly the acetabular component, results in major problems including instability and limb length discrepancy. A report by Malchau, et al. reveals that even among the best surgeons, optimal
Acetabular component malposition is the cause of half of all cases of recurrent hip dislocation. Intraoperative xrays after component insertion are helpful, yet it is certainly more useful to know the exact component position before final component insertion. The current study reviews results of
Background. Several recent reports have documented high frequency of malpositioned acetabular components, even amongst high volume arthroplasty surgeons. Robotic assisted total hip arthroplasty (THA) has the potential to improve component positioning; however, to our knowledge there are no reports examining the learning curve during the adoption of robotic assisted THA. Purpose. The purpose of this study was to examine the learning curve of robotic assisted THA as measured by component position, operative time, intra-operative technical problems, and complications. Methods. The first 105 robotic-assisted THAs performed by a single surgeon with a posterior approach from June 2011 to August 2013 patients were divided into three groups based on the order of surgery. Group A was cases 1–35, group B 36–70 and group C 71–105. Component position, operative time, intra-operative technical problems, and intra-operative complications were recorded. Results. There was no significant difference between groups A, B, and C for BMI or age (Figure 1). Gender was different between groups with 20 males in group A, 9 in group B, and 16 in group C (p < 0.05). There was no difference for mean acetabular inclination, acetabular anteversion, or leg length discrepancy between groups as experience increased (p > 0.05) (Figure 2). The average operative time for groups A, B, and C was 79.8 ± 27 min, 63.2 ± 14.2 min, and 69.4 ± 16.3 min respectively (p = 0.02). The cumulative number of outliers was two for the Lewenick safe zone and six for the Callanan safe zone. Figure 3 displays
There are numerous factors that influence total hip arthroplasty (THA) stability including surgical approach, soft-tissue tensioning, impingement, abductor status, and component positioning. A long-held tenet regarding
Introduction. The acetabular cup should be properly oriented to prevent dislocation and to reduce wear and leg length discrepancy. Despite advances in surgical techniques and instrumentation, achieving proper cup placement in total hip arthroplasty (THA) is challenging with potentially large variations of cup position and limited accuracy. We evaluated whether cup placement on anatomical location ensured original center of rotation (COR) and surgeon's experiences of THA reduced variations in
Background. The current orthopaedic literature demonstrates a clear relationship between
Introduction. Patients with abnormal spinopelvic mobility are at increased risk for hip instability. Measuring the change in sacral slope (ΔSS) with standing and seated lateral radiographs is commonly used to determine spinopelvic mobility pre-operatively. Sacral slope should decrease at least 10 degrees to demonstrate adequate accommodation. Accommodation of <10 deg necessitates
Two critical steps in achieving optimal results and minimizing complications (dislocation, lengthening, and intraoperative fracture) are careful preoperative planning and more recently, the option of intraoperative imaging in order to optimise accurate and reproducible total hip replacement. The important issues to ascertain are relative limb length, offset and center of rotation. It is important to start the case knowing the patient's perception of their limb length. Patient perception is equally important, if not more important, than the radiographic assessment. On the acetabular side, the teardrop should be identified and the amount of reaming necessary to place the inferior margin of the acetabular component adjacent to the tear drop should be noted. Superiorly the amount of exposed metal that is expected to be seen during surgery should be measured in millimeters. Once the key issues of limb length, offset, center of rotation, and
Aims: To establish whether the Ôidealñ concentric