While THA is regarded as one of the most successful surgeries in medicine, recent studies have revealed that ideal acetabular cup implantation is achieved as little as 50% of the time. Malalignment of the acetabular component in THA may result in dislocation, reduced range of motion, or accelerated wear. Recently, robotic-assisted surgery has been introduced to reduce the errors in component placement. The purpose of this study is to longitudinally assess the accuracy of cup placement of a single surgeon at three points in time: directly following a total joint fellowship, after 10 years of experience with manual instrumentation, and directly after adopting robotic technology. Three hundred patients received THA at a single center by a single surgeon representing three series of 100 consecutive patients in each series. The first series A included the surgeon's first 100 THA patients following graduation from joint fellowship (2/2000–5/2002). The second series B included the surgeon's last 100 THA patients before adopting robotic technology (12/2010–1/2012) and the final series C included the surgeon's first 100 THA patients using robotic assistance (4/2012–4/2013). The post-operative abduction and version of the cup was measured using PACS imaging software from the AP and cross-table lateral radiographs. Abduction was measured using a transverse line at the level of the teardrop and the lateral opening angle of the cup relative to this reference line. Anteversion was measured using the ischial method described by Schmalzreid on the crosstable lateral view and accounts for pelvic flexion. The average inclination for the groups A, B, and C was 48.6 ± 7.6°, 37.4 ± 6.2°, and 39.6 ± 47.6°, respectively and for anteversion was 29.3 ± 10.3°, 26.6 ± 8.4°, and 23.6 ± 5.7°, respectively. The cup placement in the original series A was within the Lewinnek safe zone only 31% of the time. This increased to 45% in series B and up to 74% in series C (p < 0.05). With the robotic series C, the three-dimensional pre-operative plan was obtained from the software. The average error (final placement–plan) was −0.7 ± 2.1° for inclination and 1.1 ± 2.0° for version. 93% of the inclination measurements and 94% of the version measurements were within 5° of the plan and 100% of both measurements were within 10° of the plan. Of note, 8% of the robotic cases were actually planned outside of the Lewinnek safe zone to accommodate for patient deformity and optimize correction to achieve the targeted combined anteversion of the acetabular and femoral components. Robotic assistance in THA leads to significantly more precise acetabular cup placement. As measured by the Lewinnek safe zone, 10 years of experience resulted in a 45% increase in precision, while adding robotic assistance resulted in a 139% increase in precision compared to the surgeon's initial performance. With greater knowledge of ideal acetabular cup position, highly accurate techniques may allow surgeons to decrease the risk of dislocation, promote durability and improve the ability to restore appropriate leg length and offset

Aims. This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH). Methods. The study analyzed a consecutive series of 69 patients who underwent robotic-arm assisted THA between September 2018 and December 2019. Of these, 30 patients had DDH and were classified according to the Crowe type. Acetabular component alignment and 3D positions were measured using pre- and postoperative CT data. The absolute differences of cup alignment and 3D position were compared between DDH and non-DDH patients. Moreover, these differences were analyzed in relation to the severity of DDH. The discrepancy of leg length and combined offset compared with contralateral hip were measured. Results. The mean values of absolute differences (postoperative CT-preoperative plan) were 1.7° (standard deviation (SD) 2.0) (inclination) and 2.5° (SD 2.1°) (anteversion) in DDH patients, and no significant differences were found between non-DDH and DDH patients. The mean absolute differences for 3D cup position were 1.1 mm (SD 1.0) (coronal plane) and 1.2 mm (SD 2.1) (axial plane) in DDH patients, and no significant differences were found between two groups. No significant difference was found either in cup alignment between postoperative CT and navigation record after cup screws or in the severity of DDH. Excellent restoration of leg length and combined offset were achieved in both groups. Conclusion. We demonstrated that robotic-assisted THA may achieve precise cup positioning in DDH patients, and may be useful in those with severe DDH. Cite this article: Bone Joint Res 2021;10(10):629–638

The metal on metal implants was introduced without the proper stepwise introduction. The ASR resurfacing hip arthroplasty (RHA) withdrawn due to high clinical failure rates and the large diameter head THA (LDH-THA) are also widely abandoned. Early (2 year) radiostereometry studies does not support early instability as cause of failure but more likely metal wear products. A possible advantage may be maintenance of bone mineral density (BMD). We present 5 year prospective follow up from a randomized series, aiming to report changes from baseline and to investigate links between implant micromotion, Cr & Co ions and BMD. Patients eligible for an artificial hip were randomized to RHA, Biomet LDH-THA or standard Biometric THA. 19, 17 and 15 patients completed 5 year follow-up. All followed with BMD of the femur, acetabulum and for RHA the collum. RHA and THA with whole blood Co and Co. LDH-THA only at 5 year. RHA had marker based RSA of both components, cup only for LDH-THA. Translations were compiled to total translation (TT= √(x. 2. +y. 2. +z. 2. )). Data were collected at baseline, 8 weeks, 6 months, 1, 2 and 5 years. Statistical tests: ANCOVA for TT movement, Spearman's correlation for BMD, Cr, Co and BMI to TT at 5 years. RSA: The 5 year median (25%to75%) RHA cup translations were X=-0.00(−0.49 to 0.19) Y=0.15(−0.03 to 0.20), z=0.24(−0.42 to 0.37) and TT 0.58 (0.16 to 1.82) mm. For the LDH-THA X=−0.33(−0.90 to 0.20) Y=0.28(0.02 to 0.54), z=0.43(−1.12 to −0.19) and TT 1.06 (0.97 to 1.72) mm. The TT was statistically different (p<0.05) for the two cups. The RHA femoral component moved X=0.37(0.21 to 0.56) Y=0.02(−0.07 to 0.11), z=-0.01(−0.07 to 0.26) and TT 0.48 (0.29 to 0.60) mm at 5 years. There was no TT movement from year 2. The mean (SD) acetabular BMD was diminished to 93(90–97)% for RHA and 97(93–99.9)% for THA, but LDH-THA maintained 99(95–103)%. Overall femoral BMD was unchanged at 5 years for all interventions, but both stemmed implants lost 17% at the calcar. Median (25%to75%) whole-blood Cr peaked in the LDH-THA group with 1.7 (0.9 to 3.1) followed by RHA 1.2 (0.8 to 5.0) and THA with 0.5 (0.4 to 0.7)ppb. For Co the highest levels were found in RHA with 1.6(0.8 to 4.7) followed by LDH-THA 1.2 (0.7–1.7) and THA 0.2 (0.2 to 0.6) ppb. The only correlations above +/−0.3 for TT were the RHA femoral component with a correlation of 0.47 to BMI, 0.30 to Co and Cr. The ASR cup conversely had a negative correlation of −0.60 to BMI and again, the LDH-THA cup had a negative correlation of −0.37 to Cr. In contrast to registered revision rates, we found significantly larger movement for the Biomet cup than the ASR cup. The metal ion levels were similar. The LDH-THA cup maintained the acetabular BMD best at 5 years, but the difference was small, we are limited by small numbers and the correlations between TT and the covariates showed no clear pattern

Aims. The aim of this study was to evaluate the diagnostic accuracy of the absolute synovial polymorphonuclear neutrophil cell (PMN) count for the diagnosis or exclusion of periprosthetic joint infection (PJI) after total hip (THA) or knee arthroplasty (TKA). Methods. In this retrospective cohort study, 147 consecutive patients with acute or chronic complaints following THA and TKA were included. Diagnosis of PJI was established based on the 2018 International Consensus Meeting criteria. A total of 39 patients diagnosed with PJI (32 chronic and seven acute) and 108 patients with aseptic complications were surgically revised. Results. Using receiver operating characteristic curves and calculating the area under the curve (AUC), an optimal synovial cut-off value of 2,000 PMN/µl was determined (AUC 0.978 (95% confidence interval (CI) 0.946 to 1)). Using this cut-off, sensitivity and specificity of absolute synovial PMN count for PJI were 97.4% (95% CI 91.2 to 100) and 93.5% (95% CI 88.9 to 98.1), respectively. Positive and negative predictive value were 84.4% (95% CI 72.7 to 93.9) and 99.0% (95% CI 96.7 to 100), respectively. Exclusion of 20 patients with acute complications improved specificity to 97.9% (95% CI 94.6 to 100). Different cut-off values for THA (< 3,600 PMN/µl) and TKA (< 2,000 PMN/µl) were identified. Absolute synovial PMN count correlated strongly with synovial alpha-defensin (AD) (r = 0.759; p < 0.001). With a positive AD result, no additional PJI could be identified in any case. Conclusion. Absolute synovial PMN count is a widely available, rapid, cost-effective, and accurate marker in PJI diagnostics, whereas synovial AD appears to be a surrogate parameter of absolute synovial PMN count. Despite limitations in the early postoperative phase, wear, and rheumatic diseases in confirming PJI, an absolute synovial PMN count below 2,000/µl is highly suitable for ruling out PJI, with specific cut-off values for THA and TKA. Cite this article: Bone Joint J 2023;105-B(4):373–381

Aims. Total hip arthroplasty (THA) is a common procedure to address pain and enhance function in hip disorders such as osteoarthritis. Despite its success, postoperative patient recovery exhibits considerable heterogeneity. This study aimed to investigate whether patients follow distinct pain trajectories following THA and identify the patient characteristics linked to suboptimal trajectories. Methods. This retrospective cohort study analyzed THA patients at a large academic centre (NYU Langone Orthopedic Hospital, New York, USA) from January 2018 to January 2023, who completed the Patient-Reported Outcomes Measurement Information System (PROMIS) pain intensity questionnaires, collected preoperatively at one-, three-, six-, 12-, and 24-month follow-up times. Growth mixture modelling (GMM) was used to model the trajectories. Optimal model fit was determined by Bayesian information criterion (BIC), Vuong-Lo-Mendell-Rubin likelihood ratio test (VLMR-LRT), posterior probabilities, and entropy values. Association between trajectory groups and patient characteristics were measured by multinomial logistic regression using the three-step approach. Results. Among the 1,249 patients, a piecewise GMM model revealed three distinct pain trajectory groups: 56 patients (4.5%) in group 1; 1,144 patients (91.6%) in group 2; and 49 patients (3.9%) in group 3. Patients in group 2 experienced swift recovery post-THA and minimal preoperative pain. In contrast, groups 1 and 3 initiated with pronounced preoperative pain; however, only group 3 exhibited persistent long-term pain. Multinomial regression indicated African Americans were exceedingly likely to follow trajectory groups 1 (odds ratio (OR) 2.73) and 3 (OR 3.18). Additionally, odds of membership to group 3 increased by 12% for each BMI unit rise, by 19% for each added postoperative day, and by over four if discharged to rehabilitation services (OR 4.07). Conclusion. This study identified three distinct pain trajectories following THA, highlighting the role of individual patient factors in postoperative recovery. This emphasizes the importance of preoperatively addressing modifiable risk factors associated with suboptimal pain trajectories, particularly in at-risk patients. Cite this article: Bone Jt Open 2024;5(3):174–183

Acetabular component positioning is commonly referenced with the pelvis in the supine position in direct anterior approach THA. Changes in pelvic tilt (PT) from the pre-operative supine to the post-operative standing positions have not been well investigated and may have relevance to optimal acetabular component targeting for reduced risk of impingement and instability. The aims of this study were therefore to determine the change in PT that occurs from pre-operative supine to post-operative standing, and whether any factors are associated with significant changes in tilt ≥13° in posterior direction. 13° in a posterior direction was chosen as that amount of posterior rotation creates an increase in functional anteversion of the acetabular component of 10°. 1097 THA patients with pre-operative supine CT and standing lateral radiographic imaging and 1 year post-operative standing lateral radiographs (interquartile range 12–13 months) were reviewed. Pre-operative supine PT was measured from CT as the angle between the anterior pelvic plane (APP) and the horizontal plane of the CT device. Standing PT was measured on standing lateral x-rays as the angle between the APP and the vertical line. Patients with ≥13° change from supine pre-op to standing post-op (corresponding to a 10° change in cup anteversion) were grouped and compared to those with a <13° change using unpaired student's t-tests. Mean pre-operative supine PT (3.8±6.0°) was significantly different from mean post-operative standing PT (−3.5±7.1°, p<0.001), ie mean change of −7.3±4.6°. 10.4% (114/1097) of patients had posterior PT changes ≥13° supine pre-op to standing post-op. A significant number of patients, ie 1 in 10, undergo a clinically significant change in PT and functional anteversion from supine pre-op to standing post-op. Surgeons should be aware of these changes when planning component placement in THA

Dislocation is one of the most common complications in total hip arthroplasty (THA) and is primarily driven by bony or prosthetic impingement. The aim of this study was two-fold. First, to develop a simulation that incorporates the functional position of the femur and pelvis and instantaneously determines range of motion (ROM) limits. Second, to assess the number of patients for whom their functional bony alignment escalates impingement risk. 468 patients underwent a preoperative THA planning protocol that included functional x-rays and a lower limb CT scan. The CT scan was segmented and landmarked, and the x-rays were measured for pelvic tilt, femoral rotation, and preoperative leg length discrepancy (LLD). All patients received 3D templating with the same implant combination (Depuy; Corail/Pinnacle). Implants were positioned according to standardised criteria. Each patient was simulated in a novel ROM simulation that instantaneously calculates bony and prosthetic impingement limits in functional movements. Simulated motions included flexion and standing-external rotation (ER). Each patient's ROM was simulated with their bones oriented in both functional and neutral positions. 13% patients suffered a ROM impingement for functional but not neutral extension-ER. As a result, 48% patients who failed the functional-ER simulation would not be detected without consideration of the functional bony alignment. 16% patients suffered a ROM impingement for functional but not neutral flexion. As a result, 65% patients who failed the flexion simulation would not be detected without consideration of the functional bony alignment. We have developed a ROM simulation for use with preoperative planning for THA surgery that can solve bony and prosthetic impingement limits instantaneously. The advantage of our ROM simulation over previous simulations is instantaneous impingement detection, not requiring implant geometries to be analysed prior to use, and addressing the functional position of both the femur and pelvis

Aims. Transfusion after primary total hip arthroplasty (THA) has become rare, and identification of causative factors allows preventive measures. The aim of this study was to determine patient-specific factors that increase the risk of needing a blood transfusion. Methods. All patients who underwent elective THA were analyzed retrospectively in this single-centre study from 2020 to 2021. A total of 2,892 patients were included. Transfusion-related parameters were evaluated. A multiple logistic regression was performed to determine whether age, BMI, American Society of Anesthesiologists (ASA) grade, sex, or preoperative haemoglobin (Hb) could predict the need for transfusion within the examined patient population. Results. The overall transfusion rate was 1.2%. Compared to the group of patients without blood transfusion, the transfused group was on average older (aged 73.8 years (SD 9.7) vs 68.6 years (SD 10.1); p = 0.020) and was mostly female (p = 0.003), but showed no significant differences in terms of BMI (28.3 kg/m. 2. (SD 5.9) vs 28.7 kg/m. 2. (SD 5.2); p = 0.720) or ASA grade (2.2 (SD 0.5) vs 2.1 (SD 0.4); p = 0.378). The regression model identified a cutoff Hb level of < 7.6 mmol/l (< 12.2 g/dl), aged > 73 years, and a BMI of 35.4 kg/m² or higher as the three most reliable predictors associated with postoperative transfusion in THA. Conclusion. The possibility of transfusion is predictable based on preoperatively available parameters. The proposed thresholds for preoperative Hb level, age, and BMI can help identify patients and take preventive measures if necessary. Cite this article: Bone Jt Open 2024;5(7):560–564

Smartphone-based apps that measure step-count and patient reported outcomes (PROMs) are being increasingly used to quantify recovery in total hip arthroplasty (THA). However, optimum patient-specific activity level before and during THA early-recovery is not well characterised. This study investigated 1) correlations between step-count and PROMs and 2) how patient demographics impact step-count preoperatively and during early postoperative recovery. Smartphone step-count and PROM data from 554 THA patients was retrospectively reviewed. Mean age was 64±10yr, BMI was 29±13kg/m2, 56% were female. Mean daily step count was calculated over three time-windows: 60 days prior to surgery (preop), 5–6 weeks postop (6wk), and 11–12 weeks postop (12wk). Linear correlations between step-count and HOOS12 Function and UCLA activity scores were performed. Patients were separated into three step-count levels: low (<2500steps/day), medium (2500-5500steps/day), and high (>5500steps/day). Age >65years, BMI >30, and sex were used for demographic comparisons. Student's t-tests determined significant differences in mean step-counts between demographic groups and in mean PROMs between step-count groups. UCLA correlated with step-count at all time-windows (p<0.01). HOOS12 Function correlated with step-count preoperatively and at 6wk (p<0.01). High vs low step count individuals had improved UCLA scores preoperatively (∆1.8,p<0.001), at 6wk (∆1.1,p<0.05), and 12wk (∆1.6,p<0.01), and improved HOOS12 Function scores preoperatively (∆8.4,p<0.05) and at 6wk (∆8.8,p<0.001). Younger patients had greater step-count preoperatively (4.1±3.0k vs 3.0±2.5k, p<0.01) and at 12wk (5.1±3.3k vs 3.6±2.9k, p<0.01). Males had greater step-count preoperatively (4.1±3.0k vs. 3.0±2.7k, p<0.001), at 6wk (4.5±3.2k vs 2.6±2.5k, p<0.001), and at 12wk (5.2±3.6k vs. 3.4±2.5k, p<0.001). Low BMI patients had greater step-count at 6wk (4.3±3.3k vs. 2.6±2.7k, p<0.01) and 12wk (5.0±3.6k vs. 3.6±2.6k, p<0.05). Daily step-count is significantly impacted by patient demographics and correlates with PROMs, where patients with high step count exhibit improved PROMs. Generic recovery profiles may therefore not be appropriate for benchmarking across diverse populations

Aims. The aim of this study was to determine whether total hip arthroplasty (THA) for chronic hip pain due to unilateral primary osteoarthritis (OA) has a beneficial effect on cognitive performance. Methods. A prospective cohort study was conducted with 101 patients with end-stage hip OA scheduled for THA (mean age 67.4 years (SD 9.5), 51.5% female (n = 52)). Patients were assessed at baseline as well as after three and months. Primary outcome was cognitive performance measured by d2 Test of Attention at six months, Trail Making Test (TMT), FAS-test, Rivermead Behavioural Memory Test (RBMT; story recall subtest), and Rey-Osterrieth Complex Figure Test (ROCF). The improvement of cognitive performance was analyzed using repeated measures analysis of variance. Results. At six months, there was significant improvement in attention, working speed and concentration (d2-test; p < 0.001), visual construction and visual memory (ROCF; p < 0.001), semantic memory (FAS-test; p = 0.009), verbal episodic memory (RBMT; immediate recall p = 0.023, delayed recall p = 0.026), as well as pain (p < 0.001) with small to large effect sizes. Attention, concentration, and visual as well as verbal episodic memory improved significantly with medium effect sizes over η. 2. partial. = 0.06. In these cognitive domains the within-group difference exceeded the minimum clinically important difference. Conclusion. THA is associated with clinically relevant postoperative improvement in the cognitive functions of attention, concentration, and memory. These data support the concept of a broad interaction of arthroplasty with central nervous system function. Cite this article: Bone Joint J 2022;104-B(3):331–340

We report the outcome of 320 primary Total Hip Arthroplasties (THA) with minimum 10-year follow-up (range 10–17 years, mean 12.6 years), performed by a single surgeon in Tauranga New Zealand, with the Exeter Contemporary Flanged all-polyethylene cup and Exeter femoral stem via a posterior approach. The aim of the study is to compare the results with the published results from the design centre and create a baseline cohort for further outcomes research in this centre. All patients were prospectively followed at 6 weeks, 1 year, 5 years, 10 years, (and 15 years when available). Of 333 cases that matched the inclusion criteria, 13 procedures in 12 patents were excluded because of concomitant bone grafting and/or supplementary cage fixation, leaving 320 primary THA procedures in 280 patients, including 26 bilateral procedures in 13 patients. Mean follow-up of the surviving cases was 12.6 (range 5.0-17.1) years. There were 12 revisions – 2 for fracture, 5 for instability, 1 for impingement pain and 4 for infection. There were no revisions for aseptic cup loosening. Kaplan-Meier survivorship with revision for aseptic loosening as the endpoint was 100% at 15.0 years (with minimum 40 cases remaining at risk). All-cause acetabular revision in 12 cases result in a Kaplan-Meier survival of 95.9% (95% CI: 93.5 to 98.3%). Cemented THA with the Exeter Contemporary Flanged cup and the Exeter stem is a durable combination with results that can be replicated outside of the design centre. The Exeter Contemporary Flanged cup has excellent survivorship at 15 years when used with the Exeter stem. Cemented THA with well-proven components should be considered the benchmark against which newer designs and materials should be compared

Aims. Iliopsoas impingement occurs in 4% to 30% of patients after undergoing total hip arthroplasty (THA). Despite a relatively high incidence, there are few attempts at modelling impingement between the iliopsoas and acetabular component, and no attempts at modelling this in a representative cohort of subjects. The purpose of this study was to develop a novel computational model for quantifying the impingement between the iliopsoas and acetabular component and validate its utility in a case-controlled investigation. Methods. This was a retrospective cohort study of patients who underwent THA surgery that included 23 symptomatic patients diagnosed with iliopsoas tendonitis, and 23 patients not diagnosed with iliopsoas tendonitis. All patients received postoperative CT imaging, postoperative standing radiography, and had minimum six months’ follow-up. 3D models of each patient’s prosthetic and bony anatomy were generated, landmarked, and simulated in a novel iliopsoas impingement detection model in supine and standing pelvic positions. Logistic regression models were implemented to determine if the probability of pain could be significantly predicted. Receiver operating characteristic curves were generated to determine the model’s sensitivity, specificity, and area under the curve (AUC). Results. Highly significant differences between the symptomatic and asymptomatic cohorts were observed for iliopsoas impingement. Logistic regression models determined that the impingement values significantly predicted the probability of groin pain. The simulation had a sensitivity of 74%, specificity of 100%, and an AUC of 0.86. Conclusion. We developed a computational model that can quantify iliopsoas impingement and verified its accuracy in a case-controlled investigation. This tool has the potential to be used preoperatively, to guide decisions about optimal cup placement, and postoperatively, to assist in the diagnosis of iliopsoas tendonitis. Cite this article: Bone Jt Open 2023;4(1):3–12

Aims. Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects. Methods. We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures. Results. Mean follow-up was 39.5 months (36 to 71), with a significant improvement in post-revision function compared to preoperative function. Graft site remodelling was rated radiologically as moderate in 31 hips (63%) and strong in 12 hips (24%). There were no cases of complete graft site dissolution. No acetabular loosening was identified. None of the patients developed clinically significant heterotopic ossification. There were twelve reoperations: six patients developed post-revision infections, three experienced dislocations, two sustained periprosthetic femur fractures, and one subject had femoral component aseptic loosening. Conclusion. Our series reports bone defect restoration with the sole use of a biphasic injectable BGS in the periacetabular region. We did not observe significant graft dissolution. We emphasize that successful graft site remodelling requires meticulous recipient site preparation. Cite this article: Bone Jt Open 2022;3(12):991–997

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 acetabular component positioning during THA is the use of fluoroscopy with the direct anterior approach. Studies have demonstrated that the supine position of the patient during surgery facilitates the use of fluoroscopic guidance, thus improving acetabular component position. A handheld, accelerometer-based navigation unit for use in total hip replacement has recently become available to assist the surgeon in positioning the acetabular component during anterior approach THA, potentially reducing the need for intra-operative fluoroscopic studies. We sought to compare the radiographic results of direct anterior THA performed with conventional instrumentation vs. handheld navigation to determine the accuracy of the navigation unit, and to see whether or not there was a reduction in the fluoroscopic time used during surgery. Furthermore, we timed the use of the navigation unit to see whether or not it required a substantial addition to surgical time. Our results demonstrate that a handheld navigation unit used during anterior approach THA had no difference with regard to acetabular cup positioning when compared to fluoroscopically assisted THA, but led to a reduction in the use of intra-operative fluoroscopy time

Aims. Total hip arthroplasty (THA) and total knee arthroplasty (TKA) are common orthopaedic procedures requiring postoperative radiographs to confirm implant positioning and identify complications. Artificial intelligence (AI)-based image analysis has the potential to automate this postoperative surveillance. The aim of this study was to prepare a scoping review to investigate how AI is being used in the analysis of radiographs following THA and TKA, and how accurate these tools are. Methods. The Embase, MEDLINE, and PubMed libraries were systematically searched to identify relevant articles. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for scoping reviews and Arksey and O’Malley framework were followed. Study quality was assessed using a modified Methodological Index for Non-Randomized Studies tool. AI performance was reported using either the area under the curve (AUC) or accuracy. Results. Of the 455 studies identified, only 12 were suitable for inclusion. Nine reported implant identification and three described predicting risk of implant failure. Of the 12, three studies compared AI performance with orthopaedic surgeons. AI-based implant identification achieved AUC 0.992 to 1, and most algorithms reported an accuracy > 90%, using 550 to 320,000 training radiographs. AI prediction of dislocation risk post-THA, determined after five-year follow-up, was satisfactory (AUC 76.67; 8,500 training radiographs). Diagnosis of hip implant loosening was good (accuracy 88.3%; 420 training radiographs) and measurement of postoperative acetabular angles was comparable to humans (mean absolute difference 1.35° to 1.39°). However, 11 of the 12 studies had several methodological limitations introducing a high risk of bias. None of the studies were externally validated. Conclusion. These studies show that AI is promising. While it already has the ability to analyze images with significant precision, there is currently insufficient high-level evidence to support its widespread clinical use. Further research to design robust studies that follow standard reporting guidelines should be encouraged to develop AI models that could be easily translated into real-world conditions. Cite this article: Bone Joint J 2022;104-B(8):929–937

Aims. Acetabular fractures are associated with long-term morbidity. Our prospective cohort study sought to understand the recovery trajectory of this injury over five years. Methods. Eligible patients at a level I trauma centre were recruited into a longitudinal registry of surgical acetabular fractures between June 2004 and August 2019. Patient-reported outcome measures (PROMs), including the 36-Item Short Form Health Survey (SF-36) physical component summary (PCS), were recorded at baseline pre-injury recall and six months, one year, two years, and five years postoperatively. Comparative analyses were performed for elementary and associated fracture patterns. The proportion of patients achieving minimal clinically important difference (MCID) was determined. The rate of, and time to, conversion to total hip arthroplasty (THA) was also established. Results. We recruited 251 patients (253 fractures), with a 4:1 male to female ratio and mean age of 46.1 years (SD 16.4). Associated fracture patterns accounted for 56.5% of fractures (n = 143). Trajectory analysis showed all timepoints had significant disability versus baseline, including final follow-up (p < 0.001). Elementary fractures had higher SF-36 PCS at six months (p = 0.023) and one year (p = 0.007) compared to associated fractures, but not at two years (p = 0.135) or five years (p = 0.631). The MCID in SF-36 PCS was observed in 37.3% of patients (69/185) between six months and one year, 26.9% of patients (39/145) between one and two years, and 23.3% of patients (20/86) between two and five years, highlighting the long recovery potential of these injuries. A significant proportion of patients failed to attain the MCID after five years (38.1%; 40/105). Conversion to THA occurred in 13.1% of patients (11/110 elementary and 22/143 associated fractures). Approximately two-thirds of THAs (21/33 patients; 63.6%) were performed within two years of index surgery. Conclusion. Acetabular fractures significantly impact physical function. Recovery trajectory is often elongated beyond one year, with two-thirds of our patients displaying persistent clinically relevant long-term disability. Cite this article: Bone Joint J 2024;106-B(1):69–76

Aims. The aim of this study was to explore the relationship between reason for revision total hip arthroplasty (rTHA) and outcomes in terms of patient-reported outcome measures (PROMs). Methods. We reviewed a prospective cohort of 647 patients undergoing full or partial rTHA at a single high-volume centre with a minimum of two years’ follow-up. The reasons for revision were classified as: infection; aseptic loosening; dislocation; structural failure; and painful THA for other reasons. PROMs (modified Oxford Hip Score (mOHS), EuroQol five-dimension three-level health questionnaire (EQ-5D-3L) score, and visual analogue scales for pain during rest and activity), complication rates, and failure rates were compared among the groups. Results. The indication for revision influenced PROMs improvement over time. This finding mainly reflected preoperative differences between the groups, but diminished between the first and second postoperative years. Preoperatively, patients revised due to infection and aseptic loosening had a lower mOHS than patients with other indications for revision. Pain scores at baseline were highest in patients being revised for dislocation. Infection and aseptic loosening groups showed marked changes over time in both mOHS and EQ-5D-3L. Overall complications and re-revision rates were 35.4% and 9.7% respectively, with no differences between the groups (p = 0.351 and p = 0.470, respectively). Conclusion. Good outcomes were generally obtained regardless of the reason for revision, with patients having the poorest preoperative scores exhibiting the greatest improvement in PROMs. Furthermore, overall complication and reoperation rates were in line with previous reports and did not differ between different indications for rTHA. Cite this article: Bone Joint J 2022;104-B(7):859–866

As the American population ages and a trend toward performing total hip arthroplasty (THA) in younger patients continues, the number of Americans undergoing THA is projected to increase over time. The advent of the bundled payment system combined with the current medical utilization climate has placed considerable pressure on surgeons to produce excellent results with early functional recovery and short hospital stays. The US obesity epidemic has transcended into the arthroplasty patient population and surgeons must assess whether obesity is a risk factor for poor outcomes in THA and determine how it should be managed. We performed a recent literature review to determine how obesity impacts outcomes in total hip arthroplasty and what must be done to improve outcomes in the obese arthroplasty patient. Our goal is to answer 3 questions: does obesity increase the complication rate in THA, if obesity matters how obese is too obese, and what must be done to improve outcomes in the obese patient?. Ultimately, obesity has been shown to correlate with increased post-operative complications in THA. The arthroplasty surgeon must optimise the obese patient prior to surgery by identifying associated comorbidities and consider malnutrition screening with counseling. Notice should be taken of the degree of obesity as patients with BMI > 40 have demonstrated much higher complication rates. Strong consideration should be given to avoiding direct anterior approach in the obese patient. Healthy weight loss must be encouraged with appropriate patient counseling and treatment in order to achieve success with THA in obese patients.  

Aims. In countries with social healthcare systems, such as Canada, patients may experience long wait times and a decline in their health status prior to their operation. The aim of this study is to explore the association between long preoperative wait times (WT) and acute hospital length of stay (LoS) for primary arthroplasty of the knee and hip. Methods. The study population was obtained from the provincial Patient Access Registry Nova Scotia (PARNS) and the Canadian national hospital Discharge Access Database (DAD). We included primary total knee and hip arthroplasties (TKA, THA) between 2011 and 2017. Patients waiting longer than the recommended 180 days Canadian national standard were compared to patients waiting equal or less than the standard WT. The primary outcome measure was acute LoS postoperatively. Secondarily, patient demographics, comorbidities, and perioperative parameters were correlated with LoS with multivariate regression. Results. A total of 11,833 TKAs and 6,627 THAs were included in the study. Mean WT for TKA was 348 days (1 to 3,605) with mean LoS of 3.6 days (1 to 98). Mean WT for THA was 267 days (1 to 2,015) with mean LoS of 4.0 days (1 to 143). There was a significant increase in mean LoS for TKA waiting longer than 180 days (2.5% (SE 1.1); p = 0.028). There was no significant association for THA. Age, sex, surgical year, admittance from home, rural residence, household income, hospital facility, the need for blood transfusion, and comorbidities were all found to influence LoS. Conclusion. Surgical WT longer than 180 days resulted in increased acute LoS for primary TKA. Meeting a shorter WT target may be cost-saving in a social healthcare system by having shorter LoS. Cite this article: Bone Jt Open 2021;2(8):679–684

Aims. As our population ages, the number of octogenarians who will require a total hip arthroplasty (THA) rises. In a value-based system where operative outcomes are linked to hospital payments, it is necessary to assess the outcomes in this population. The purpose of this study was to compare outcomes of elective, primary THA in patients ≥ 80 years old to those aged < 80. Methods. A retrospective review of 10,251 consecutive THA cases from 2011 to 2019 was conducted. Patient-reported outcome (PRO) scores (Hip disability and Osteoarthritis Outcome Score (HOOS)), as well as demographic, readmission, and complication data, were collected. Results. On average, the younger cohort (YC, n = 10,251) was a mean 61.60 years old (SD 10.71), while the older cohort (OC, n = 609) was 84.25 years old (SD 3.02) (p < 0.001). The OC had greater surgical risk based on their higher mean American Society of Anesthesiologists (ASA) scores (2.74 (SD 0.63) vs 2.30 (SD 0.63); p < 0.001) and Charlson Comorbidity Index (CCI) scores (6.26 (SD 1.71) vs 3.87 (SD 1.98); p < 0.001). While the OC stayed in the hospital longer than the YC (mean 3.5 vs 2.5 days; p < 0.001), there were no differences in 90-day emergency visits (p = 0.083), myocardial infarctions (p = 0.993), periprosthetic joint infections (p = 0.214), dislocations (p = 0.993), or aseptic failure (p = 0.993). The YC was more likely to be readmitted within 90 days (3.88% vs 2.18%, Β = 0.57; p = 0.048). There were no observed differences in 12-week (p = 0.518) or one-year (p = 0.511) HOOS scores. Conclusion. Although patients ≥ 80 years old have a greater number of comorbidities than younger patients, they had equivalent perioperative complication rates and PRO scores. This study demonstrates the safety and success of elective THA in octogenarians. Cite this article: Bone Jt Open 2021;2(7):535–539

Aims. To investigate the extent of bone development around the scaffold of custom triflange acetabular components (CTACs) over time. Methods. We performed a single-centre historical prospective cohort study, including all patients with revision THA using the aMace CTAC between January 2017 and March 2021. A total of 18 patients (18 CTACs) were included. Models of the hemipelvis and the scaffold component of the CTACs were created by segmentation of CT scans. The CT scans were performed immediately postoperatively and at least one year after surgery. The amount of bone in contact with the scaffold was analyzed at both times, and the difference was calculated. Results. The mean time between the implantation and the second CT scan was two years (1 to 5). The mean age of the patients during CTAC implantation was 75 years (60 to 92). The mean scaffold-bone contact area increased from 16% (SD 12.6) to 28% (SD 11.9). The mean scaffold-bone distance decreased from a mean of 6.5 mm (SD 2.0) to 5.5 mm (SD 1.6). None of the CTACs were revised or radiologically loose. Conclusion. There was a statistically significant increase of scaffold-bone contact area over time, but the total contact area of the scaffold in relation to the acetabular bone remained relatively low. As all implants remained well fixed, the question remains to what extend the scaffold contributes to the observed stability, in relation to the screws. A future design implication might be an elimination of the bulky scaffold component. This design modification would reduce production costs and may optimize the primary fit of the implant. Cite this article: Bone Joint J 2024;106-B(4):359–364

Femoral trans-trochanteric rotational osteotomy(TRO) is widely used for the younger patients who have idiopathic osteonecrosis of femoral head. However, it usually converts to THA, and in hip arthroplasty, the procedure is commonly technically demanding and surgeon needs higher level of surgical technique. This study was designed to investigate comparison between simple THA and THA following TRO, and indicates specific surgical techniques of THA following TRO. Materials and Methods. Between 2002 and 2012, the senior authors performed 20 cementless THA in 16 patients who had followed after TRO. The operation time, blood loss, post-operative X-ray findings, and overall clinical results (JOA score) were investigated. These data were compared with simple THA following 10 years. Results. A mean duration between TRO and THA was 58 month, a mean age at the time of THA was 52.1 years old. Pre-operative classification was all Type C and stage 2 or higher stage. Osteonecrosis of femoral head before THA was mean 56.2%. Operation time was 160 minutes, and mean blood loss was 764 g. In post-operative X-ray findings, a cup was at original anatomy in place in all cases. There is a tendency of slight varus femoral stem position after THA following TRO. The JOA score was improved from 42.1 to 74.2. Discussion. Technically, there are a couple of issues in THA following TRO. Specific surgical techniques are needed. Surgical results depend on hip range of motion before THA. There is a difficulty of improvements in ROM after THA following TRO

Introduction. Accurate acetabular cup orientation could lead to successful surgical results in total hip arthroplasty (THA). We introduce a novel CT-based three-dimensional (3D) planning system, HipCOMPASS (Fig.1) and TARGET (Fig.2), which enable to design suitable alignment not only cup also surgical devices calculatingly, according to each pelvic inclination. Patients and Methods. We performed THA in 45 hips in 43 patients (female 37 and 6 men) between April 2014 and October 2015. Average age were 68 years old. THA operation was based on each parameter of the cup and device, providing a preoperative planning by ZedView system. HipCOMPASS and TARGET is linked with ZedView software, which is simultaneously calibrated adjustable parameters on this devices. Cup alignment was assessed by ZedView as well. Results. The differences of component alignment from the preoperative planning were shown in Tables. Conclusion. HipCOMPASS and TARGET might be more accurate than conventional method and more accessible system than navigation system in THA

Arthritis of the hip is a relatively common problem in patients with neuromuscular disorders due to muscle imbalance around the hip from weakness, paralysis, contractures and spasticity. Neuromuscular disorders such as cerebral palsy, Parkinson's disease, poliomyelitis, previous cerebrovascular accident (CVA) and Charcot arthropathy have been considered by many to be contraindications to total hip arthroplasty (THA). The presence of certain anatomic abnormalities (excessive femoral anteversion, acetabular dysplasia, leg length discrepancy (LLD) and coax valga) and significant soft tissue contractures, muscle imbalance, and muscular weakness make THA a challenging surgical procedure in this patient population, and can predispose to dislocation and poor functional outcome following surgery. THA can, however, result in substantial pain relief and functional improvement, and can be safely performed, provided certain technical considerations are addressed. The patient's motor strength and functional status (ambulatory vs. “sitter”) should be carefully assessed preoperatively, since both of these factors may affect the choice of surgical approach and component position. Significant soft tissue contractures should be released at the time of surgery. Although these can be frequently performed “open”, percutaneous adductor tenotomy is occasionally necessary for patients with significant adduction contractures. Patients requiring significant soft tissue releases may benefit from 6 weeks of bracing to allow soft tissues to heal in appropriately and minimise risk of dislocation during this period of time. Use of modular femoral components that allow for correction of excessive femoral anteversion, should be considered in patients with coexistent dysplasia and neuromuscular disease (i.e., CP or polio). Large femoral head components should also be considered in patients with increased risk factors for dislocation. Despite their obvious theoretical advantages, the use of large head metal on metal THAs should be used with extreme caution in view of growing concerns about these devices. Although constrained acetabular liners are associated with an increased risk of mechanical failure, their use should be strongly considered in patients with significant motor weakness or major soft tissue deficiencies. Meticulous soft tissue closure of the capsule of the hip is recommended, especially when performing THA through a posterior approach. Patients with neuromuscular disorders associated with spasticity and involuntary movements need to be optimally treated medically prior to and indefinitely after THA. There are limited reports of outcomes following THA in patients with neuromuscular disorders, however, some generalizations based on underlying diagnosis can be made. Patients with cerebral palsy and polio frequently have acetabular dysplasia, excessive femoral anteversion and LLD, and although durability does not seem to be a major concern, dislocation and instability is relatively common and needs to be addressed. Durability and instability do not appear to be major concerns in patients with Parkinson's disease, however, these patients have frequent medical complications perioperatively and have deterioration in function over time due to the progressive nature of their underlying disorder. Patients with previous CVA also appear to have acceptable durability and dislocation risk, but are at high risk of developing heterotopic ossification postoperatively. Patients with Charcot arthropathy or myelodysplasia are at high risk of instability and appear to have limited functional improvement following THA. As a result, the consensus of opinion is that THA is contraindicated in these patients

Aims. Dual mobility (DM) bearings are an attractive treatment option to obtain hip stability during challenging primary and revision total hip arthroplasty (THA) cases. The purpose of this study was to analyze data submitted to the American Joint Replacement Registry (AJRR) to characterize utilization trends of DM bearings in the USA. Methods. All primary and revision THA procedures reported to AJRR from 2012 to 2018 were analyzed. Patients of all ages were included and subdivided into DM and traditional bearing surface cohorts. Patient demographics, geographical region, hospital size, and teaching affiliation were assessed. Associations were determined by chi-squared analysis and logistic regression was performed to assess outcome variables. Results. A total of 406,900 primary and 34,745 revision THAs were identified, of which 35,455 (8.7%) and 8,031 (23.1%) received DM implants respectively. For primary THA, DM usage increased from 6.7% in 2012 to 12.0% in 2018. Among revision THA, DM use increased from 19.5% in 2012 to 30.6% in 2018. Patients < 50 years of age had the highest rates of DM implantation in every year examined. For each year of increase in age, there was a 0.4% decrease in the rate of DM utilization (odds ratio (OR) 0.996 (95% confidence interval (CI) 0.995 to 0.997); p < 0.001). Females were more likely to receive a DM implant compared to males (OR 1.077 (95% CI 1.054 to 1.100); p < 0.001). Major teaching institutions and smaller hospitals were associated with higher rates of utilization. DM articulations were used more commonly for dysplasia compared with osteoarthritis (OR 2.448 (95% CI 2.032 to 2.949); p < 0.001) during primary THA and for instability (OR 3.130 (95% CI 2.751 to 3.562) vs poly-wear; p < 0.001) in the revision setting. Conclusion. DM articulations showed a marked increase in utilization during the period examined. Younger patient age, female sex, and hospital characteristics such as teaching status, smaller size, and geographical location were associated with increased utilization. DM articulations were used more frequently for primary THA in patients with dysplasia and for revision THA in patients being treated for instability. Cite this article: Bone Joint J 2020;102-B(7 Supple B):27–32

Introduction. Accurate acetabular cup orientation could lead to successful surgical results in total hip arthroplasty (THA). We introduce a novel CT-based three-dimensional (3D) planning system, HipCOMPASS (Fg.1) and TARGET (Fig.2), which enable to design suitable alignment not only cup also surgical devices calculatingly, according to each pelvic inclination. Patients and methods. We performed THA in 13 patients (10 female and 3 men) between September 2014 and April 2014. Average age were 67 years old. THA operation was based on each parameter of the cup and device, providing a preoperative planning by ZedView system. HipCOMPASS and TARGET is linked with ZedView software, which is simultaneously calibrated adjustable parameters on this devices. Cup alignment was assessed by ZedView as well. Result. The differences of component alignment from the preoperative planning were shown in table. Conclusion. HipCOMPASS and TARGET might be more accurate than conventional method and more accessible system than navigation system in THA

An outpatient total hip arthroplasty (THA) will be defined as a THA performed at an ambulatory care facility where the patient is discharged the same day as the procedure. Such procedures are being done in the United States and the hypothesis is that a “same day” THA will lead to reduced costs and improved outcomes. However, there are no appropriately powered randomised controlled trials evaluating outcomes in this group of patients to support this hypothesis. It appears that a “same day” THA is here to stay. Therefore, the selection criteria for patients that undergo the procedure needs to be carefully defined. The safety of this regimen needs to be confirmed. In an evaluation of the NSQIP database, Otero et al. compared outcomes in patients discharged on POD 0 and POD 1 and noted that THA patients in the POD 0 group had increased rates of complications. Risk factors for complications included age >70, smoking, COPD, CAD and hematocrit less than 36. In addition, the patients discharged on POD 0 had higher rates of diabetes, steroid use and lower hematocrit. Clearly, the selection criteria for this procedure needs to be defined. In two separate studies, Goyal et al. and Dorr et al. noted that approximately 25% of patients were unable to leave the hospital on POD 0 usually because of nausea and/or hypertension. Issues to consider before developing a same day discharge program include: 1) Is the patient healthy enough to go home the same day as the surgery?; 2) Does the patient live close enough to the hospital to be discharged the same day?; 3) Can the family provide the appropriate care for the patient at home?; 4) Is it really better for the patient or just better for the surgeon?. If a surgeon embarks on a same day discharge program, rigorous selection criteria must be instituted and followed. In addition, the patient must have free choice with respect to a same day discharge versus a 24-hour stay

The goal is to avoid letting femoral deformity force suboptimal implant position/fixation. Suboptimal implant position has an adverse effect on hip biomechanics and often on hip function and durability. Classification - Practical approach to femoral deformities: categorise into 3 main groups: 1.) Very proximal, 2.) Subtrochanteric, 3.) Distal. Management of distal deformities: Most can be ignored if there is sufficient room to place conventional femoral implant. Management of proximal deformities: Option 1: Use implants that allow satisfactory positioning despite deformity…or… Option 2: Remove the deformity. Management of subtrochanteric level deformities: These are the most difficult. Problems: 1.) Too proximal to ignore, 2.) Too distal to bypass. Main treatment options: 1.) Resurfacing THA, 2.) Short stem THA, 3.) Corrective osteotomy with THA. Corrective osteotomy with THA: 1.) Perform osteotomy at level of deformity, 2.) In most cases a corrective osteotomy that creates a transverse osteotomy junction is simplest, 3.) Use an implant that provides reliable fixation in the femur (usually uncemented), 4.) Use implant that provides fixation of the proximal and distal fragments. Majority of proximal femoral deformities managed with one-stage procedure: 1.) Excise deformity and replace with metal, 2.) Implants that allow ignoring deformity, 3.) Corrective osteotomy

Osteolysis is one of a major cause of failure that affect long term survival rate in THA. Hard-on-hard bearing surface were developed to reduce wear and osteolysis, such as ceramic-on-ceramic which is the lowest wear rate was introduced but it still has squeaking and ceramic fracture. Metal-on-metal bearing surface significantly reduce wear rate but it still release metal ion which affect local tissue reaction. Then ceramic-on-metal is another choice of bearing with combine the advantage of reduce wear rate, metal ion release, no stripe wear, no squeaking and no ceramic fracture. However after clinical use ALTRs may occur and disturb the longevity of THA. During January 2009 to December 2009 we performed 98 THR with the same femoral stem and acetabular cup with difference bearing which were 87 cases of metal on cross-linked PE, 8 cases of ceramic on metal and 5 cases of metal on metal. Routinely postoperative care were done with clinical evaluation, plain x-rays and Harris hip score. After 5 years follow up there are clinical problems in ceramic on metal THA with decrease clinical score and progressive osteolysis in radiographic finding in 2 cases then we investigated to find the cause of this problem and revise the components. We preformed magnetic resonance imaging and collect blood sample for ESR, CRP and Cobalt and Chromium level. We revised 2 cases of ceramic on metal THA, during surgery we collected tissue for bacterial and AFB and histopathology. All retrieval components were studied for wear pattern. First patient have thigh pain and progressive osteolysis after year 4. th. of follow up. She had normal ESR and CRP with high level of cobalt and chromium level. We revised both components and tissue histopathology showed metallosis with chronic inflammation. Another patient had failure due to ALTRs with mixed solid-cystic mass at trochanteric bursa but component is stable then only bearing surface were change. Wear pattern at femoral head was in weight bearing area with corresponding to apical center wear of metal liner. Our study showed that only in group of ceramic-on-metal THA that have 5 years follow up have early reoperation due to osteolysis and tissue reaction. We routinely stop to use this bearing since 2010. But we have small number of cases in our study to conclude that is bearing are not suitable for clinical usage

(Introduction). Metal on Metal (MoM) THA bearing as the second generation Total Hip Arthroplasty, widely came into use in Japan since 2000s. And it was expected to be able to ensure long-term use, the range of motion in the joints after surgeries, and the resistance to the dislocation, because MoM THAhad been considered to be able to use the large diameter head for its lower wear. However, there are some reports that the metal wear debris from MoM bearing surface generates the elevated serum ion level in the blood and the incidence of pseudotumor may occur subsequent to the metal wear debris. We performed MoM THA for 291 joints in 234 patients in our hospital since May 2005. But now, we refrain to use this. In this time, we will describe two cases of pseudotumor after implantation of MoM THA. (Case1) Age 64 years, female. This case showed the hip osteoarthritis on the right side, and we performed MoM THA in 2005. After that, she had slipped just prior to the three-year postoperative check-up, andstarted swelling up, hip joint pain, and the rise in CRP. Then, we performed to remove pesudotumor in 2008 and her CRP turned into negative. However, she was repeating hip dislocation several times and an MRI showed recur of pseudotumor. Finally, we changed her metal liner into a polyethylene liner in 2012. (Case2) Age 57 years, female. This case showed the hip osteoarthritis on the bilateral side, and we performed MoM THA in 2005. We had regularly measured her serum ion levels since 2009, and her cobalt level was indicating high concentration. In addition, there was shown 46ng/ml blood concentration of cobalt in her postoperative check-up in 2013. In 2014, she came to our hospital with chief complaint of the pain in the right groin, and we confirmed pseudotumor with MRI. (Conclusion). Nowadays, there have been various reports regarding the formation of mass lesion around the joint implants with MoM bearing, and the incidence rates, the methods of the diagnosis, and the treatment policies are introduced. However, they are realistically still not standardized. For this reason, we should fully understand the properties of MoM THA to perform the surgeries. And there is a need to be performed CT scans, MRI and ultrasound examination for the patients who claim a pain or the sense of discomfort in the area after surgery

Proximal load fixation in THA is paramount for maximum bone preservation and thus longevity of the implant. Conventional femoral stems may not achieve satisfactory proximal fixation in proximal/ distal femoral canal mismatch as in champagne type of femur, mal-united fractures, excessively bowed femur and some young large patients. Such mismatch can lead to uneven loading and a higher incidence of loosening or periprosthetic fracture. This risk is becoming higher with the recent trend to mini-invasive surgery. As an alternative to standard stem, the short stem femoral prosthesis was originally developed in the 1950’s and has recently been making a resurgence as a design conducive to the minimal invasive techniques, and allows for greater preservation of the natural anatomy. Our objective is to measure the clinical and radiological outcomes of the Metha. ®. hip short stem (a cementless, metaphyseal fix conserving diaphysis implant) with computer assisted technique and minimal invasive surgical approach. This study is a single center, open label, data collection study of 35 consecutive subjects undergoing OrthoPilot. ®. navigation, Metha. ®. stem plasmapore cup system with minimal invasive muscle sparing surgical approach. (B. Braun Aesculap; Tuttlingen, Germany). Pre-Operatively an IRB Informed Consent, no exclusion specific to the implant, Harris Hip Evaluation and routine hip/pelvis plain xray was performed. Post-Operatively, a CT Scan within 6 months, repeat Harris Hip Score (HHS) Evaluation. The implant is made of titanium alloy with plasmapore coating in @ 2/3 of the implant (< 8 cm engages in proximal femur with a total length average of 10.75 cm)(range 9.75–11.75). The bearing surface is metal/ highly cross linked polyethylene. Size 32 head of modular neck with plasmapore shell. All cases were done thru muscle sparing anterolateral mini invasive approach. At 6 months ± 1 month with an average age = 67, BMI= 37 (one was 360 pounds), Harris score was 46 preop and 96 post op.No thigh pain, No dislocation, Trendelenberg negative. Patient satisfaction was high. One fell had a non displaced fx of the neck that did not require revision but slowed full weight bearing for 6 weeks. One subsided in a 360 pound patient after he went full wt bearing while getting out of the shower a week after surgery. This was revised with a standard stem. The tip of two implants was discovered to have penetrated the proximal femur with no symptoms at 3 months period and no restriction to weight bearing during that period. This happened in the first 5 cases in which we modified technique with no other penetrations. Xray/CT scan showed no subsidence good bony ingrowth no radiolucency or loosening. The two penetrated corteses showed intense bony overgrowth on the two protruded tips of stem. We conclude that cementless metaphyseal short stem with proximal plasmapore coating is associated with excellent clinical and radiological results. The technical errors we faced in the early two cases were identified and avoided by using awl canal finder with suction tube palpation of canal and direct visualization of the metaphyses before hammering the broach. The combination of the short stem prosthesis, modularity of the neck, computer assisted technique and minimal invasive arthroplasty is expected to reduce recovery time, increase the potential for successful restoration of function and add to the longevity of the prosthetic joint

Intra-operative fractures of the femur are on the rise mainly due to the increased use of cementless implants and the desire to get a tight press fit. The prevalence has been reported to be between 1–5% in cementless THAs. The key to preventing these fractures is to identify patients at high risk and careful surgical technique. Surgical risk factors include the use of cementless devices, revision hip surgery, the use of flat tapered wedges and MIS surgery. Patient factors that increased risk include increasing age, female gender, osteopenia and rheumatoid arthritis. These risk factors tend to be additive and certainly when more than one is present extra caution needs to be taken. Surgical technique is critical to avoid these intra-operative fractures. Fractures can occur during exposure and dislocation, during implant removal (in revision THA), during canal preparation and most commonly during stem insertion. In both primary, and especially in revision, THA be wary of the stiff hip in association with osteopenia or osteolysis. These patients require a very gentle dislocation. If this cannot be achieved, then alteration of the standard approach and dislocation may be needed. Examples of these include protrusion with an osteopenic femur and revision THA with a very stiff hip with lysis in the femur. Lastly, in cases with retained hardware, dislocate prior to removing plates and screws. After dislocation, the next challenge is gentle preparation of the femoral canal. A reasonable exposure is required to access the femoral canal safely. MIS procedures do not offer good access to femoral canal and this probably results in increased risk of fracture during broaching or implant insertion. When broaching, stop when broach will not advance further. When inserting a tapered wedge stem, be worried if stem goes further in than broach. In revision surgery, when taking the stem out from above, make sure the area of the greater trochanter does not overhang the canal. A high speed burr can clear the shoulder for easier access for removal. In revision THA with an ETO, place a cerclage wire prior to reaming and retighten prior to stem insertion. Even with careful surgical technique intra-operative femoral fractures will still occur. When inserting the stem, a sudden change in resistance is highly suggestive of fracture. Wide exposure of the entire proximal femur is necessary to confirm the diagnosis. The distal extent of the fracture must be seen. Only on occasion is an intra-operative radiograph needed. Management is directed to ensuring component stability and good fracture fixation. In primary total hip arthroplasty, calcar fractures are by far the most common. If using proximal fixation and you are certain the stem is stable, then all that is needed is cerclage wiring. As already mentioned, you must follow the fracture line distally so you are aware of how far down it goes. Often what appears to be a calcar split actually propagates distal to the lesser trochanter. In these cases, one would probably go for distal fixation plus wiring. In conclusion, intra-operative femoral fractures are on the rise. Prevention is the key

Arthritis of the hip is a relatively common problem in patients with neuromuscular disorders due to muscle imbalance around the hip from weakness, paralysis, contractures and spasticity. Neuromuscular disorders such as cerebral palsy, Parkinson's disease, poliomyelitis, previous cerebrovascular accident (CVA) and Charcot arthropathy have been considered by many to be relative contraindications to total hip arthroplasty (THA). The presence of certain anatomic abnormalities (excessive femoral anteversion, acetabular dysplasia, leg length discrepancy (LLD) and coax valga) and significant soft tissue contractures, muscle imbalance, and muscular weakness make THA a challenging surgical procedure in this patient population, and can predispose to dislocation and poor functional outcome following surgery. THA can, however, result in substantial pain relief and functional improvement in patients with significant hip arthritis and neuromuscular disorders, and can be safely performed, provided certain technical considerations are addressed. The patient's motor strength and functional status (ambulatory vs. “sitter”) should be carefully assessed pre-operatively, since both of these factors may affect the choice of surgical approach and component position. Significant soft tissue contractures should be released at the time of surgery. Although these can be frequently performed “open”, percutaneous adductor tenotomy is occasionally necessary for patients with significant adduction contractures. Patients requiring significant soft tissue releases may benefit from 6 weeks of bracing to allow soft tissues to heal appropriately and minimise risk of dislocation during this period of time. Use of modular femoral components that allow for correction of excessive femoral anteversion, should be considered in patients with coexistent dysplasia and neuromuscular disease (i.e. CP or polio). Large femoral head components should also be considered in patients with increased risk factors for dislocation. Despite their obvious theoretical advantages, the use of large head metal on metal THAs should be used with extreme caution in view of growing concerns about these devices. Although constrained acetabular liners are associated with an increased risk of mechanical failure, their use should be strongly considered in patients with significant motor weakness or major soft tissue deficiencies. Meticulous soft tissue closure of the capsule of the hip is recommended, especially when performing THA through a posterior approach. Patients with neuromuscular disorders associated with spasticity and involuntary movements need to be optimally treated medically prior to and indefinitely after THA. There are limited reports of outcomes following THA in patients with neuromuscular disorders, however some generalisations based on underlying diagnosis can be made. Patients with cerebral palsy and polio frequently have acetabular dysplasia, excessive femoral anteversion and LLD, and although durability does not seem to be a major concern, dislocation and instability is relatively common and needs to be addressed. Durability and instability do not appear to be major concerns in patients with Parkinson's disease, however, these patients have frequent medical complications perioperatively and have deterioration in function over time due to the progressive nature of their underlying disorder. Patients with previous CVA also appear to have acceptable durability and dislocation risk, but are at high risk of developing heterotopic ossification postoperatively. Patients with Charcot arthropathy or myelodysplasia are at high risk of instability and appear to have limited functional improvement following THA. As a result, the consensus of opinion is that THA is contraindicated in patients with Charcot arthropathy and myelodysplasia

Introduction: The goal is to avoid letting femoral deformity force suboptimal implant position/fixation. Suboptimal implant position has an adverse effect on hip biomechanics and often on hip function and durability. Classification: Practical approach to femoral deformities: categorise into 3 main groups: Very proximal, Subtrochanteric, Distal. Management: Management of distal deformities: Most can be ignored if there is sufficient room to place conventional femoral implant. Management of proximal deformities: Option 1: Use implants that allow satisfactory positioning despite deformity…or… Option 2: Remove the deformity. Management of subtrochanteric level deformities: These are the most difficult. Problems: Too proximal to ignore, Too distal to bypass. Main treatment options: Resurfacing THA, Short stem THA, Corrective osteotomy with THA. Corrective osteotomy with THA: Perform osteotomy at level of deformity, In most cases a corrective osteotomy that creates a transverse osteotomy junction is simplest, Use an implant that provides reliable fixation in the femur (usually uncemented), Use implant that provides fixation of the proximal and distal fragments. Conclusions: Majority of proximal femoral deformities managed with one-stage procedure: Excise deformity and replace with metal, Implants that allow ignoring deformity, Corrective osteotomy

Aim. Prosthetic joint infection (PJI) is a major complication in THA. Nasal carriage with S. Aureus is a well-defined risk factor for infection in hospitalized patients. Risk for infection is reduced up to 50% by eradication therapy. Since PJI rates are very low and only 25% of the population are carriers, significant differences are hard to show and reports on PJI have been inconclusive. We analysed the effect of S. Aureus eradication therapy in THA. Methods. From 2011, patients receiving THA are screened for S. Aureus carriage and carriers are treated. This group was retrospectively compared with a historical THA group in which no screening and eradication therapy was done. We assumed similar carrier rates in both groups and calculated the risk reduction of eradication therapy for PJI in comparison to the historical carriers without treatment. Fisher's Exact test was used to compare outcome. Results. 2072 patients were screened and 478 patients were positive (23%). The historical control group consisted of 1248 patients, with 288 calculated carriers (23%). 15 PJI (0.72%) occurred vs 14 (1.12%) in the historical group (p=0.16). A 52% reduction in S. Aureus infections was found (0.33% vs 0.64% p=0.15). Infection rates for PJI caused by S. aureus was similar in non-carriers and carriers after eradication therapy (0.3 vs 0.4% p=0.506). The calculated infection rates in carriers in the historical group was reduced from 2.6% to 0.8% (RR 3,25, p=0.07) by eradication therapy and from 1.7% to 0,4% (RR 4,25, p=0.07) for S. Aureus PJI. Conclusions. A clear trend in reduction of PJI was demonstrated as a result of S. aureus screening and eradication therapy, reducing the rate of PJI for carriers to the same level as non-carriers

Background. Fifteen to twenty percent of patients presenting for total hip arthroplasty (THA) have bilateral disease. While simultaneous bilateral THA is of interest to patients and surgeons, debate persists regarding its merits. The majority of previous reports on simultaneous bilateral THA involve patients in the lateral decubitus position, which require repositioning, prepping and draping, and exposure of a fresh wound to pressure and manipulation for the contralateral THA. The purpose of this study was to compare complications, component position, and financial parameters for simultaneous versus staged bilateral THAs using the direct anterior approach (DAA). Methods. Medical records were reviewed for patient demographics, medical history, operative time, estimated blood loss (EBL), change in hemoglobin, transfusion, tranexamic acid (TXA) use, length of stay (LOS), discharge disposition, leg length discrepancy, acetabular cup position, and perioperative complications. Cost and reimbursement data were analyzed. Results. Forty-four patients were included in the sequential group and fifteen patients in the simultaneous group (Figure 1). Operative time was significantly longer for simultaneous DAA THA, with procedures lasting 260 +/− 48 minutes compared to 132 +/− 30 minutes for a single arthroplasty in the sequential group (p<0.001). Patients undergoing simultaneous bilateral DAA THA also had a significantly higher EBL (p<0.001), hemoglobin drop (p<0.001), and blood transfusion rate (p<0.01) compared to parameters for a single arthroplasty in the sequential group. This was despite TXA being used in a significantly higher proportion of simultaneous procedures compared to sequential procedures (p<0.01). The LOS was significantly longer in patients undergoing simultaneous bilateral DAA THA (2.9 +/− 1.0 days) compared to sequential (2.2 +/− 0.6 days) (p<0.001). No deep venous thrombosis (DVT) or pulmonary embolism (PE) was detected in either group during the observation period. No significant difference was detected regarding perioperative complications or whether patients were able to be discharged home instead of to a post-inpatient facility (Figure 2). There was no significant difference in component position, complications, or readmissions between groups. Total cost per hip was significantly less for the simultaneous ($15,565 +/− 1,470) compared to the sequential group ($19,602 +/− 3,094) (p<0.001). There was no significant difference in total payments between the simultaneous group ($25,717 +/− 4,404) and the sequential group ($24,926 +/− 8,203) (p=0.93). Thus, with lower cost and similar reimbursement, profit per hip was significantly higher for the simultaneous ($9,606 +/− 5,060) compared to the sequential group ($5,324 +/− 7,997) (p<0.05). (Figure 3). Conclusions. Significant data regarding simultaneous bilateral THA has been published but results are conflicting and different surgical approaches were used. To our knowledge only four previous reports have been published examining simultaneous bilateral THA performed via the DAA. While simultaneous DAA THA presents challenges, our results suggest that simultaneous DAA THA may add value to the healthcare system without resulting in increased complications compared to sequential hip arthroplasty

Collagen and hyaluronic acid are two major components of intervertebral disc (IVD). They give resistance and hydration to Nucleus Pulposus. In this study, we assessed the impact of Collagen (COLL) and Hyaluronic acid-Tyramine (THA) contents on the mechanical properties and the structure of composite hydrogels. For this purpose, a range of composites were obtained using a 4 mg/mL collagen concentration and different COLL/THA ratios from 8:1 to 1:5 (w/w). Composite gelling was performed by pH increase, triggering collagen fibrillogenesis and oxidative coupling of tyramine moieties in THA catalyzed by H. 2. O. 2. and horseradish peroxidase (HRP). To modulate the THA gelling kinetic, different HRP concentrations (0.05; 0.1 and 0.5 U/mL) were used. Composites with a low THA content exhibited a fibrillar structure and possessed mechanical properties close to those of pure collagen hydrogels (200 Pa). From the ratio 1:1, the storage modulus increased to reach c.a 1200 Pa for the ratio 1:5. From the ratio 1:2, the fibrillar structure disappeared and sheets, characteristic of THA hydrogels, were observed. The HRP activity dramatically impacted the physical properties. A rapid THA gelling associated with a high THA content tended to destabilize collagen fibrils and promoted the formation of covalent bond between collagen and THA. On the opposite a slow gelling kinetic favored collagen fibril formation up to the COLL/THA ratio 1:2. Taken together, these results show that a slow gelling and an 8 mg/mL THA concentration are the appropriate conditions to obtain biomimetic biomaterials for the treatment of Nucleus Pulposus

Arthritis of the hip is a relatively common problem in patients with neuromuscular disorders due to muscle imbalance around the hip from weakness, paralysis, contractures and spasticity. Neuromuscular disorders such as cerebral palsy, Parkinson's disease, poliomyelitis, previous cerebrovascular accident (CVA) and Charcot arthropathy have been considered by many to be relative contraindications to total hip arthroplasty (THA). The presence of certain anatomic abnormalities (excessive femoral anteversion, acetabular dysplasia, leg length discrepancy (LLD) and coax valga) and significant soft tissue contractures, muscle imbalance, and muscular weakness make THA a challenging surgical procedure in this patient population, and can predispose to dislocation and poor functional outcome following surgery. THA can, however, result in substantial pain relief and functional improvement in patients with significant hip arthritis and neuromuscular disorders, and can be safely performed, provided certain technical considerations are addressed. The patient's motor strength and functional status (ambulatory vs. “sitter”) should be carefully assessed pre-operatively, since both of these factors may affect the choice of surgical approach and component position. Significant soft tissue contractures should be released at the time of surgery. Although these can be frequently performed “open,” percutaneous adductor tenotomy is occasionally necessary for patients with significant adduction contractures. Patients requiring significant soft tissue releases may benefit from 6 weeks of bracing to allow soft tissues to heal in appropriately and minimize risk of dislocation during this period of time. Use of modular femoral components that allow for correction of excessive femoral anteversion, should be considered in patients with coexistent dysplasia and neuromuscular disease (i.e. CP or polio). Large femoral head components should also be considered in patients with increased risk factors for dislocation. Despite their obvious theoretical advantages, the use of large head metal on metal THAs should be used with extreme caution in view of growing concerns about these devices. Although constrained acetabular liners are associated with an increased risk of mechanical failure, their use should be strongly considered in patients with significant motor weakness or major soft tissue deficiencies. Meticulous soft tissue closure of the capsule of the hip is recommended, especially when performing THA through a posterior approach. Patients with neuromuscular disorders associated with spasticity and involuntary movements need to be optimally treated medically prior to and indefinitely after THA. There are limited reports of outcomes following THA in patients with neuromuscular disorders, however some generalisations based on underlying diagnosis can be made. Patients with cerebral palsy and polio frequently have acetabular dysplasia, excessive femoral anteversion and LLD, and although durability does not seem to be a major concern, dislocation and instability is relatively common and needs to be addressed. Durability and instability do not appear to be major concerns in patients with Parkinsons disease, however, these patients have frequent medical complications perioperatively and have deterioration in function over time due to the progressive nature of their underlying disorder. Patients with previous CVA also appear to have acceptable durability and dislocation risk, but are at high risk of developing heterotopic ossification post-operatively. Patients with Charcot arthropathy or myelodysplasia are at high risk of instability and appear to have limited functional improvement following THA. As a result, the consensus of opinion is that THA is contraindicated in patients with Charcot arthropathy and myelodysplasia

Malposition of cups and stems in THA leads to a higher rate of dislocation and wear, to leg length discrepancies and to a higher revision rate. Surgical navigation of the implant components should lead to a more accurate position of THA. 1481 consecutive THA were evaluated from November 2001 to June 2006. In a first series until December 2002 127 THA with navigated cups were compared with 110 manually implanted THA. In a second series all following 766 THA with navigated cups were compared to 384 THA with both navigated cup and stem. Navigated surgery was done as a routine procedure by all surgeons, from residents to consultants. Evaluation was done for radiographs, clinical results, the navigation system data for cup anteversion and inclination, centre of rotation, leg lengthening, offset and antetorsion of the stem, technical exclusions and intra- and postoperative complications as dislocation, seroma, thrombosis and duration of surgery. The results showed a better alignment in inclination and anteversion of navigated cups compared to non navigated cups and additional improvement when cup and stem were navigated. In stem navigation a good control of the leg lengthening and a reliable prediction of the safe range of motion could be seen. The overall dislocation rate was 0.3% in the navigated groups after December 2002. Thrombosis, seroma and infection were seen in a very low rate in all groups

Objective. Total Hip Arthroplasty (THA) and Total Knee Arthroplasty (TKA) bring relief of pain and functional disability to patients with end stage osteoarthritis, however the literature on their impact on patients’ level of physical activity (PA) is scarce. Methods. Cross-sectional study, performed in 2012, in 515 patients who underwent THA/TKA surgery in 2010–2011 and a random sample of persons aged >40 years from the Dutch general population participating in a national survey in the same period. PA in minutes per week (min/week) and adherence to the Dutch recommendation for health enhancing PA was measured by means of the Short QUestionnaire to ASsess Health enhancing PA (SQUASH) Additional assessments included socio-demographic characteristics, the presence of comorbidities, BMI and Short Form-12. Multivariable linear (total min/week) and logistic regression analyses (meeting PA recommendation), adjusting for confounders, were performed for THA and TKA separately. Results. 258 THA patients (64% female, mean age 70.0 (SD9.2)), 221 TKA patients (67% female, mean age 70.2 (SD8.9)) and 4373 persons from the general population sample (52% female, age 59.0 (SD12.0)) were included. In both regression analyses, the presence of joint arthroplasty was statistically significantly associated with more total min/week spent on PA (THA 7.0% increase, 95%-CI (2.0%–12.6%); TKA 7.4% increase, 95%-CI (1.6%–13.4%)) and a higher chance of adherence with PA recommendations (THA OR 1.90, 95%-CI (1.12–3.03); TKA OR 1.94, 95%-CI (1.19–3.15)). Conclusion. 6-18 months after surgery, THA/TKA patients were more physically active than a random sample of persons >40 years from the Dutch general population

Background. The short stem prosthesis showed good results in patients with primary osteoarthritis. However, there were a few studies about the short stem THA in patients with osteonecrosis of the femoral head (ONFH). Objective. To evaluate the clinical and radiographic results of the short stem THA in patients with ONFH. The authors hypothesized that the short stem THA would be a promising procedure for patients with ONFH. Material and Method. The authors reviewed 120 osteonecrotic hips in 93 patients who underwent THA with Metha® short stem from November 2010 to February 2013. The appearance of bone trabeculae development and radiolucent line was reviewed using Gruen's classification. The Harris hip score (HHS) was recorded at 6, 12, 24 and 36 months postoperative for evaluating the clinical results. Results. The mean age of patients was 44.4 years (18–68) with the mean BMI of 22.7 (15.1–32.5, SD 3.5). The average follow-up period was 29.2 months (20–47). The mean HHS was significantly improved from 43.9 (22.7–74, SD 7.7) preoperatively to 97.7 (85.9–100, SD 2.7) at 6 months postoperatively (p<0.01). The radiographic change around the stems showed bone trabeculae development at zone 1 (77 cases)(64.2%), 2 (27 cases)(22.5%), 3 (106 cases)(88.3%), 6 (120 cases)(100%) and 7 (115 cases)(95.8%). There was 1 case (0.8%) of 5 mm subsidence and the radiolucent line was observed in zone 1. There were 6 cases (5%) of intraoperative femoral fractures and were treated with cerclage wires, no further subsidence was observed. There was 1 case (0.8%) of distal stem perforation which had stable bone ingrowth. No revision was required. Conclusion. The clinical and radiographic results of the short stem THA in patients with ONFH are generally satisfactory. Its design enables preservation of the bone stock and the bone trabeculae appear to confirm the assumption of proximal force transmission. The authors believe that the short stem THA is a promising procedure for patients with ONFH

The transgluteal approach (TG) offers a user-friendly alternative to the heavily promoted anterior approach (DA) to total hip arthroplasty (THA). Our purpose is to illustrate the advantages and details of the technique, illustrate the surgical anatomy that differentiates TG from the “traditional posterior” technique, and point out the surprising similarities to the DA. Unlike the traditional posterior THA, the TG preserves ITB, quadratus, and obturator externus. The conjoined tendon is released, providing direct access to the femur via the piriformis fossa. Direct acetabular access is facilitated either by using a portal through which reaming and cup impaction are performed or offset instrumentation. Intra-operative digital radiography was used in all cases. We present the clinical and radiographic outcome of 850 consecutive primary THA using the TG. At 2–6 years follow-up, dislocation rate was 0.3%, cup abduction 35–50 degrees in 97%, 92% used a cane within 5 days, 61% reported driving within the first post-operative week. No intra-operative trochanteric fractures, nerve injuries, or wound problems were observed. Three calcar fractures were wired. Hospital stay averaged 1.5 days, no patient received a blood transfusion if their pre-operative hematocrit was normal, and 88% of patients were discharged on acetaminophen only. The TG is a reliable and highly successful alternative to commonly used soft tissue sparing approaches in THA. It permits accelerated recovery while assuring optimal component orientation. The surgeon familiar with the traditional posterior approach can embark on a gradual learning curve that can minimise the complication rate as the surgeon learns the technique

Background. With the rising demand for primary total hip arthroplasty (THA), there has been an emphasis on reducing the revision burden and improving patient outcomes. Although studies have shown that primary THA effectively minimizes pain and restores normal hip function for activities of daily living, many younger patients want to participate in more demanding activities after their operation. The purpose of this study was to examine the relationship between age, gender and patient satisfaction after total hip arthroplasty. Methods. With IRB approval, 2 groups of subjects were enrolled in this study: (i) 143 patients at an average of 25 months (range 10–69 months) post-primary THA, and (ii) 165 control subjects with no history of hip surgery or hip pathology. All subjects were assigned to one of four categories according to their age and gender: Group A: 40–60 year old males (31 THA; 42 Controls), Group B: 40–60 year old females (25 THA; 53 Controls), Group C: 60–80 year old males (35 THA; 25 Controls), and Group D: 60–80 year old females (36 THA; 23 Controls). Each patient completed a self-administered Hip Function Questionnaire (HFQ) which assessed each subject's satisfaction, expectations, symptoms and ability to perform a series of 94 exercise, recreational and daily living activities. These included participation in work-out activities, adventure and water sports, running and biking, and contact and team sports. Each participant was also asked their activity frequency, symptom prevalence and satisfaction with their hip in performing each activity. Results. When compared to controls, more THA patients reported at least weekly pain (20% vs. 7% p=0.001), stiffness (16% vs. 9% p=0.06), and dependence on analgesics at least weekly (8% vs. 5% p=0.42). Males age 40–60 were the only subgroup to differ significantly from their comparators in regards to pain, stiffness, or analgesic use (pain: 29% vs. 7% p=0.02; stiffness: 29% vs. 5% p=0.007; analgesics: 19% vs. 2% p=0.04). Looking at frequency of pain, more controls were dissatisfied than THA patients (64% vs 21% p=0.02). There were 12% of THA patients reporting their hip does not feel normal compared to 6% of controls (p=0.06); elderly males reported this more frequently than controls (p=0.016) and their elderly female counterparts (p=0.028). Of the effect modifiers tested, sensation of an abnormal hip (p=0.03) and frequent stiffness (p=0.003) portend lower satisfaction ratings while history of THA leads to better satisfaction rating vs. Control (p< 0.0001). Age and sex groups (p=0.33), the presence of pain (p=0.13), and analgesic use (p=0.16) were not significant modifiers. Discussion. Residual symptoms, especially stiffness, and the sensation that their hip is not normal after THA are negatively impact patient satisfaction, yet they are not uncommon in THA patients. Young THA males tend to experience more postoperative symptoms, however they remain satisfied and tolerate these symptoms well. Older THA males are less likely to report a normal feeling hip, but are generally satisfied with the outcome of THA

Background. Because of the long life expectancy of young total hip arthroplasty (THA) patients and the limited durability of prosthetic implants in young patients, surgeon's always must take into account that the primary THA will be revised in the future. Therefore, not only the survival of the primary total hip in young patients is important, but we would also like to accentuate the revisability of a primary THA in this specific and high demanding patient population. Methods. Based on our philosophy, we always use cemented hip in young patients, if needed with acetabular bone impaction grafting. 343 consecutive cemented THA in 270 patients under the age of 50 years were evaluated, all implanted between 1988 and 2006. We also assessed the results of the revised THA (n=53) within the same population. Clinical, radiographical and survival of primary and revision THA were evaluated. Outcome. Survival analysis of all 343 hips with endpoint revision for any reason of either component showed a survival of 86% after 10 years. Survival of the stem and cup with endpoint aseptic loosening 93% after 10 years. Remarkably, the THA in which the cemented cup was combined with acetabular bone impaction grafting had a survival of 90% (SE 2.8) in contrast to a survival of 82% (SE 3.4) of the cups without an acetabular revision with endpoint revision for any reason of the whole prostheses(log-rank test, p=0.156) at 10 years. With no patient lost during follow-up, 53 primary hips were revised after a mean follow-up of 8.9 (range 2.0–19.3) years. The average follow-up of the revision THA was 4.2 (range 0.1–14.8) years. Three hips of this revision cohort needed a repeat revision, two had a reinfection after a septic revision and one revised cup failed 12 years after revision. The survival of the revised cohort with endpoint revision for any reason was 91% after 5 years, with endpoint aseptic loosening the survival at 5 years was 100 %. As well after primary as revision THA good clinical outcome scores were measured. Interpretation. Cemented implants in young patients showed satisfying results in primary as well as after revision THA with very acceptable survival and clinical outcomes. Keeping in mind that the young patient will outlive their primary THA, the primary hip has to be revisable and the results of the revision THA must be as good as the primary THA. Bone defects both in primary and revision THA can be successful managed with impacted bone grafts, without the need for augments, cages or larger implants

Introduction. The purpose of this retrospective study was to review the outcome of THA in the treatment of bilateral hip ankylosis of different causes; surgical, septic or spontaneous. Methods & Material. 20 THA procedures in 10 patients were included in the study, 5 males and 5 females all had bilateral fusion. Previous pathologies included: ankylosing spondylitis, AVN, septic arthritis and surgical arthrodesis. Flexion deformity ranged (10°-45°). Shortening as compared to normal anatomy was up to 6 cm and leg length discrepancy (LLD) ranged from 1 cm to 2.5 cm. Most unified X-ray finding was massive osteophytes formation with 3 patients showing severe narrowing of the femoral canal. Operative time averaged 147 minutes (70–210) and lateral approach was used in all patients, anesthesia was general with only 3 undergoing spinal anesthesia. Results. Serious complications were reported and were related to the correction of LLD; 1 incidence of sciatic nerve injury that recovered in one year, and another incidence of femoral nerve injury (sensory > motor) that recovered within 3 months, and one case of incomplete correction of LLD. At 5 years follow up (minimum 6 month), there is no loosening or revision. Discussion. The conversion of bilateral fused hip joints to THA is a very rewarding surgery but with higher risk of complications

Dislocation after THA is the most common complication in modern THA, The reported failure rate of reoperation for recurrent instability is higher than any other indication for revision surgery. Treatment of dislocation after THA. Non-operative treatment. The first episode of dislocation after THA is usually treated by close reduction with or without brace treatment. There is no agreement about the role and effectiveness of bracing. Generally, bracing is indicated in the following circumstances:. First dislocation. Early laxity. No component malposition. Patients with poor general condition. The main management issues are about managing recurrent instability. Treatment choice is often complex and management begins by identifying the cause of instability. Causes to consider:. Component issue. Impingement. Soft tissue imbalance. Laxtiy. Abductor weakness. Trochanteric non-uion. Surgical Treatment. The decision to use operative treatment to stabilize the hip joint is complex and the surgeon must take into consideration:. How many times the hip dislocated. Interveral between dislocation. How long after THA the dislocation occur. Can the problem be solved by an operation. Operative risks. Treatment choices depends on the underlying mechanism of dislocation:. Correction of malposition. Correction of soft tissue laxity. Release contractures. Addressing problems of impingement. Using a large femoral head. Constrained liners

The alumina on alumina articulation in THA has induced less macrophage reaction and cytokine section than polyethylene bearings. Thus THA using alumina on almina articulation has induced little periprosthetic osteolysis. However alumina fracture is still a concern. We had underwent 100 THAs that it was a cemented polyethylene backed acetabular component with an alumina inlay(ABS Cup; Kyocera, Kyoto, Japan), PHS stem(Kyocera) and 28mm alumina femoral head. This system was formerly used in only Japan, over 10 years results have not reported yet. We retrospectively reviewed 94 patients(100 hips) with cemented alumina on alumina THAs to identify factors relating to alumina failure, and to evaluate mid-term(>10years) results. 16 patients died from unrelated causes within 10 years of the operation and 14 patients was lost to follow up. The remaining 70 patients(79 Hips) were evaluated after a mean follow-up of 10 years. We performed clinical evaluation using the JOA score, and radiological evaluation was performed that inclination and anteversion angle of cup measurement with 2D template system at anteroposterior radiograph. On the radiographs at the final examination, radiolucency and osteolysis were evaluated around the acetabular component, and around the femoral component. These evaluations were scheduled for 3,6,9, and 12 months and yearly thereafter. All the operations were performed by same surgeon, at same center. Cumulative survival rates were calculated using the Kaplan-Meier method with failure defined as the end point of revision for alumina failure or for any reason. To compare groups with and without alumina failures in age, BMI, gender, activity, function, abduction angle, size of component, or existence of radiolucent lines, we used the nonparametric Mann-Whitney U-test. The mean age of the patients at surgery was 63.0 years. The mean follow up term was 13.8 years. Inclination and anteversion mean angle of cup were 45.6°and 14.2°.ã��Revision surgery was performed because of alumina inlay failure in 4hips(2 fractures and 2 dissociation;5.1%), loosening in 2 hips(2 cup loosenings; 2.5%) recurrent dislocation in 1 hip, and femoral fracture in 1 hip, no deep infection and DVT. The 10-year survival rate was 92.4% with revision for any reason and 95.9% with revision for alumina failure as the end point. We detected 3 ceramic failures at a mean of 8.9 years(4.1ï¼ï¿½12.5) after the index operation. There were no differences in BMI, function, cup angles(inclination and anteversion), and cup loosening among the 4hips with alumina failure. But there were differences in age, gender, and activity with alumina failure. This alumina on alumina THA yielded passably mid-term results, but it was occurred a high rate of catastrophic alumina inlay failure. In July 2000, we discontinued use of this type of THA to avoid alumina failure. This ABS cup was banned in 2002, because of numerous alumina failures. We suggest all patients with this type of acetabular component be followed carefully. Cemented polyethylene-backed alumina-on-alumina THA with a composite of alumina inlay had a relatively high rate of catastrophic alumina inlay failure(5.1ï¼ï¿½) during a mean of 13.8 years' follow up. There were differences in age, gender, and activity with alumina failure

Mini-posterior technique advantages: Familiar anatomy; Widely applicable; Predictable (and thus preventable) sources of errors; Demonstrated functional advantages over the 2-incision THA in recent prospective randomised trials and in direct comparison studies. Familiar anatomy: A substantial number of surgeons routinely use the posterior approach; With careful attention to skin incision placement and leg positioning intraoperatively it is relatively easy for most surgeons to shorten the skin incision; With the addition of specialised retractors, offset reamers and offset cup and stem inserters many THA can be done with a skin incision of 10cm or less; Easily converted to standard posterior approach if intraoperative concerns arise; Formal posterior capsular repair substantially lowers historical risk of dislocation. Widely applicable: With relatively little variation this approach can be used for a broad range of THA patients; Several variations of the mini-posterior technique exist (Sculco, Dorr, Swanson, Goldstein); Dorr technique has been used in my practice and we have studied it extensively in direct comparison studies against the 2-incision technique

While total hip arthroplasty (THA) has been shown successful at relieving pain and improving function in patients with coxarthrosis, wear and instability remain leading causes for revision surgery. Highly crosslinked polyethylene (HXPE) has significantly reduced wear and osteolysis but volumetric wear associated with the use of larger diameter ball heads may be an issue in the long-term. Finally, concerns with femoral taper corrosion have increased the utilization of ceramic ball heads in recent years. Ceramic on ceramic articulations are optimised for both minimizing implant wear and instability. It is biocompatible, wettable, and possesses the lowest in vitro and in vivo wear rates among all bearing couples. In fact, wear rates are lowest when the ceramic ball head size is maximised. Additionally, modern ceramic on ceramic THA designs have had an excellent clinical track record with low rates of loosening, failure, and no reports of osteolysis in even highly active, young patients. Concerns with ceramics center around issues related to fracture risk, squeaking, and cost. While the phenomenon of squeaking remains poorly understood, the reliability of ceramic implants have steadily improved with better materials, design, and manufacturing. The fracture risk for modern pure alumina implants and the newer alumina matrix composite ceramics are 1 in 5000 and 1 in 100,000, respectively. The advantages of ceramic on ceramic THAs will not be realised on every patient and therefore, should be selectively used. However, with expected increases in life expectancy and more young, active patients undergoing THA, ceramic on ceramic THA should be strongly considered in patients under age 60 years

Intra-operative fractures of the femur are on the rise mainly due to the increased use of cementless implants and the desire to get a tight pressfit. The prevalence has been reported to be between 1–5% in cementless total hip arthroplasties (THAs). The key to preventing these fractures is to identify patients at high risk and careful surgical technique. Surgical risk factors include the use of cementless devices, revision hip surgery, the use of flat tapered wedges and MIS surgery. Patient factors that increased risk include increasing age, female gender, osteopenia and rheumatoid arthritis. These risk factors tend to be additive and certainly when more than one is present extra caution needs to be taken. Surgical technique is critical to avoid these intra-operative fractures. Fractures can occur during exposure and dislocation, during implant removal (in revision THA), during canal preparation and most commonly during stem insertion. In both primary and especially in revision THA, be wary of the stiff hip in association with osteopenia or osteolysis. These patients require a very gentle dislocation. If this cannot be achieved, then alteration of the standard approach and dislocation may be needed. Examples of these include protrusion with an osteopenic femur and revision THA with a very stiff hip with lysis in the femur. Lastly, in cases with retained hardware, dislocate prior to removing plates and screws. After dislocation, the next challenge is gentle preparation of the femoral canal. A reasonable exposure is required to access the femoral canal safely. MIS procedures do not offer as good access to femoral canal and this probably results in increased risk of fracture during broaching or implant insertion. When broaching, stop when broach will not advance further. When inserting a tapered wedge stem, be worried if stem goes further in than broach. In revision surgery when taking the stem out from above, make sure the greater trochanter does not overhang the canal. A high speed burr can clear the shoulder for easier access for removal. In revision THA with an ETO place a cerclage wire prior to reaming and retighten prior to stem insertion. Even with careful surgical technique intra-operative femoral fractures will still occur. When inserting the stem a sudden change in resistance is highly suggestive of fracture. Wide exposure of the entire proximal femur is necessary to confirm the diagnosis. The distal extent of the fracture must be seen. Only on occasion is an intra-operative radiograph needed. Management is directed to ensuring component stability and good fracture fixation. In primary total hip arthroplasty calcar fractures are by far the most common. If using proximal fixation and you are certain the stem is stable, then all that is needed is cerclage wiring. As already mentioned, you must follow the fracture line distally so you are aware of how far down it goes. Often what appears to be a calcar split actually propagates distal to the lesser trochanter. In these cases, one would probably go for distal fixation plus wiring. In conclusion intra-operative femoral fractures are on the rise. Prevention is the key. If a fracture, exposure is the key to deciding on a treatment plan

18 Patients with SCD and 2ndry Osteoarthritis of their hips due to Avascular Necrosis underwent uncemented THA. There were 12 male and 6 female patients. Patient had their pre op WOMAC/SF-36/HOOS/and Oxford hip scores recorded preoperatively a well as 3 month, 6months and one year post op. The outcome scores at one year were significantly better than the pre operative scores. However, when compared to a matched cohort of patients who underwent THA for reasons other than SCD/AVN, e.g. primary OA, rheumatoid arthritis, post traumatic OA, the WOMAC pain score improvement was less

Economic data, clinical outcome studies, and anatomical studies continue to support the Superior Hip Approach as a preferred approach for improved safety, maximal tissue preservation, rapid recovery, and minimised cost. Clinical studies show exceedingly low rates of all major complications including femur fracture, dislocation, and nerve injury. Economic data from Q1 2013 to Q2 2016 demonstrate that CMS-insured patients treated by the Superior Hip Approach have the lowest cost of all patients treated in Massachusetts by an average of more than $7,000 over 90 days. The data show that the patients treated by the Superior Hip Approach have lower cost than any other surgical technique. Matched-pair bioskills dissections demonstrate far better preservation of the hip joint capsule and short external rotators than the anterior approach. Design principles include: Preservation of the abductors; Preservation of the posterior capsule and short external rotators; Preparation of the femur in situ prior to femoral neck osteotomy; Excision of the femoral head, thereby avoiding surgical dislocation of the hip; In-line access to the femoral shaft axis; Ability to perform a trial reduction; Independence from intra-operative imaging; Independence from a traction table; Applicable to at least 99% of THA procedures. Conclusion. In contrast to the results of the Superior Approach, the anterior approach continues to show difficulties with wound problems, infection, intra- and post-operative fracture, and failure of femoral component osseointegration and even dislocation. Evidence continues to demonstrate that the Superior Hip Approach has advantages over all other surgical approaches to the hip

Introduction:. Since2007, we have used CT-based fluoroscopy-matching navigation system (Vector Vision Hip Ver.3.5.2, BrainLAB, Germany) in revision total hip arthroplasty. This system completes the registration procedure semi-automatically by matching the contours of fluoroscopic images and touching 3 adequate points to the contours of 3D bone model created in the computer. Registration procedure using fluoroscopic figures has finished before making surgical incision. It needs no elongation time during the operation. The objective of this study was to evaluate the accuracy of CT-based fluoroscopy-matching navigation system in revision THA. Material and method:. We analysed the acetabular cup in consecutive 33 hips with both intra-operative and post-operative alignment data (based on navigation system and CT evaluation) We further compared these measurements with results from primary THA. Data for primary THA were therefore obtained from 40 consecutive patients who underwent primary THA between August 2007 and May 2013 using the same navigation system by postero-lateral approach. We aimed the cup angle for Revision THA as following, the inclination: 40 degrees, the anteversion: 20 degrees Anteversion on the navigation system must be adjusted by the pelvic tilt. Results:. There was one dislocation in 33 Revision THAs. There was no other obvious complication (nerve palsy, VTE and Infection). The all cup alignments were within 7 degrees from the preoperative orientation. In the Revision THA group the differences between the intra- and post-operative measurement of cup inclination were 2.3 ± 1.9 degrees. The differences of cup anteversion were 2.7 ± 2.5 degrees. In the primary THA group, the differences between the intra- and post-operative measurement of cup inclination were 1.9 ± 2.1 degrees. The differences of cup anteversion were 2.1 ± 2.5 degrees. There was no significant difference with two groups. Discussion:. CT-based navigation THA is very useful for severe deformity of hip osteoarthritis. We had used CT-based navigation system (landmark matching) since 2003. It needs some technical skills to improve the accuracy of landmark matching. The registration with CT-based fluoroscopy-matching navigation system is much easier and more simple than with landmark matching navigation system. CT images of revision patients included metal artifacts caused by implants. However this system is not so affected by metal artifacts. And we found this system provided high accuracy even in revision THA

Background. Assessment of functional outcome after total hip arthroplasty (THA) often involves subjective patient-reported outcome measures (PROMs) whereas analysis of gait allows more objective assessment. The aims of the study were to compare longitudinal changes of WOMAC function score and ambulatory gait analysis after THA, between patients with low and high self-reported levels of physical function. Methods. Patients undergoing primary THA (n=36; m/f=18/18; mean age=63.9; SD=9.8yrs; BMI=26.3 SD=3.5) were divided in a high and low function group, on their preoperative WOMAC function score. Patients were prospectively measured preoperatively and 3 and 12 months postoperatively. WOMAC function scores 0–100) were compared to inertial sensor based ambulatory gait analysis. Results. WOMAC function scores significantly improved in both low and high groups at 3 months postoperatively whereas gait parameters only improved in with a low pre-operative function. Between 3 and 12 months postoperatively, function scores had not significantly further improved whereas several gait parameters significantly improved in the low function group. WOMAC function scores parameters were only moderately correlated (Spearman's r = 0.33–0.51). Discussion. In routine longitudinal assessment of physical function following THA, ambulatory gait analysis can be supplementary to WOMAC. As gait significantly improved during the first 3 months and following 9 months after THA in patients with a low preoperative level of physical function only, assessment of more demanding tasks than gait may be more sensitive to capture functional improvement in patients with high preoperative function. Acknowledgements. This article presents independent research funded by the National Institute for Health Research (NIHR) under its Programme Grants for Applied Research programme (RP-PG-0407-10070). The views expressed in this article are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. The research team acknowledges the support of the NIHR, through the Comprehensive Clinical Research Network

The aim of this study was to validate the information on operating room ventilation reported to the Norwegian Arthroplasty Register (NAR). We then wanted to assess the influence of operating room ventilation on the rate of revision due to infection after primary THA performed in operating rooms with conventional ventilation, “greenhouse”–ventilation and Laminar Airflow ventilation (LAF). We identified cases of THA revisions due to deep infection and the type of ventilation system reported to the NAR from the primary THA. We included 5 orthopaedic units reporting 17947 primary THAs and 136 (0.8%) revisions due to infection during the 28 year inclusion period from 1987 to 2014. The hospitals were visited and the current and previous ventilation systems were evaluated together with the hospitals head engineer, and the factual ventilation on the specific operating rooms was thereby assessed. The association between revision due to infection and operating room ventilation was estimated by calculating relative risks (RR) in a Cox regression model. 73% of the primary THAs were performed in a room with LAF, in contrast to the reported 80 % of LAF. There was similar risk of revision due to infection after THA performed in operating rooms with laminar air flow compared to conventional ventilation (RR=0.7, 95 % CI: 0.2–2.3) and after THA performed in operating rooms with “greenhouse”-ventilation compared to conventional ventilation (RR=1.2, 0.1–11). Surgeons are not fully aware of what kind of ventilation there is in the operating room. This study may indicate that, concerning reduction in incidence of THA infection, LAF does not justify the substantial installation cost. The numbers in the present study are too small to conclude strongly. Therefore, the study will be expanded to include all hospitals reporting to the NAR

Prevention of joint dislocation after total hip arthroplasty (THA) is important to keep suitable relationships between surgeons and patients. Capsule has an essential role for stability of joint, especially in hip. Reserving a part of capsule in THA can increase stability. We examined the effect of partial capsulotomy in hip joint for prevention of dislocations after THA. In 178 primary THA for osteoarthritis, partial capsulotomy were performed in 92 cases and generous capsulectomy in 86 cases from 1993 to 2001. Age, gender, pre-operative complications of both groups were matched. All THA were performed from a posterior approach, and in case of partial capsulotomy, anterior one third of hip joint capsule was reserved before placing acetabular component. Posterior capsulorrhaphy was not performed. No hip dislocations have been seen in partial capsulotomy cases, and four posterior dislocations following THA were observed in general capsulectomy cases during one to nine year follow up. Soft tissue imbalance of THA is most at risk for dislocation. The present study showed a satisfying result of partial capsulotomy for prevention of THA dislocation. Residual hip joint capsule can increase joint stability and can resist to dislocation after THA in osteoarthritis

Osteoarthritis (OA) of the hip is the most common indication for total hip replacement (THR). Obesity is a risk factor for the development of OA and has recently resulted in patients requiring THRs at much younger ages to relieve pain at the joint capsule and restore mobility. However, the impact of obesity on THR mortality is not well understood.

An updated systematic review was performed to identify whether an obese BMI should influence patient selection for surgery. Specifically, the impact of obesity on short-term mortality, long-term mortality, and peri- and post-operative complications was assessed with a particular focus on BMI classes.

A comprehensive literature search of Ovid Medline and EMBASE in November 2022 identified relevant papers in accordance with PRISMA methodology. After removing duplicates, 2988 articles underwent strict inclusion and exclusion criteria, resulting in 12 papers for analysis.

There was no statistically significant difference in mortality risk between obese and non-obese populations. Obesity was associated with a lower risk of short-term mortality than in the normal weight control group, however there was an increased mortality risk in obese patients long-term likely due to comorbidities. Obese patients were significantly younger than normal BMI and underweight patients. However, the paper found increased mortality risk in underweight and morbidly obese patients.

Obese patients did not have an increased risk of mortality when compared to non-obese patients following THR. Obesity may have a protective effect on mortality up to a BMI of 40kg/m2, although this may be influenced by the obesity paradox which states only the healthiest obese individuals are selected for surgery, which could attribute to a lower mortality risk. The greatest risk of mortality and complication was associated with underweight patients. As a result, a BMI greater than 30kg/m2 may not necessitate a hip replacement contraindication. It is important surgeons apply careful consideration and comprehensive risk assessment on patients who require a THR, especially at the BMI extremes.

Introduction. Most Japanese patients who receive total hip arthroplasty (THA) are osteoarthritic and 70% have development dysplasia of the hip. Their stature is shorter than average and their sizes (acetabular cup and femoral stem) are smaller. The Taperloc Microplasty (BIOMET) is a short femoral stem. It was launched on July 2012 in Japan (extended on January 2013). It is essentially a shortened version of the Taperloc stem (35mm shorter than the standard stem). Objectives. We aimed to evaluate the outcomes of minimally invasive anterolateral THA using a short stem. Methods. We retrospectively reviewed all 56 patients who underwent THA at our hospitals between July 2013 and April 2015. Of these 28 (50%) were performed with short stems. The surgical approach was antero-lateral in the lateral position. The patients (4 men and 24 women) had a mean age at surgery of 66.5 years (range, 46–85 years). The original diseases were osteoarthritis (25 patients) and osteonecrosis (3 patients). We investigated the system type, size (cup, femoral head, and stem), radiological findings and complications (fracture, infection, deep vein thrombosis, and dislocation). Results. There were no severe complications, such as, infection, deep vein thrombosis, or dislocation. One patient had a femur fracture during operation and was switched to a standard stem. The mean surgery duration was 102 minutes (range, 80–142 minutes) and the mean amount of bleeding during surgery was 254 g (range, 95–720 g). Mean cup size was 51.0 mm (range, 48–60 mm) and stem size is 6 (range, 4–13). Radiological findings showed 2 patients had stem subsidence (within 5mm). One of them had severe osteoporosis and the other patient had leg length discrepancy. Conclusions. Minimally invasive anterolateral THA using a short femoral stem has good clinical and radiological results in Japanese patients. Long-term results should be further observed prospectively

Introduction: Although Metal wires and cables are popular tools to fix greater trochanter in revision THA, non union, pain and breakage are well known. For these situations, we used polyethylene tape which is occasionally applied for the spine surgery. The purpose of this study is to evaluate clinical result of greater trochanter fixation using polyethylene tape in revision THA cases. Materials and Methods: We retrospectively reviewed patients who underwent revisions THA (six cases) and re-revision THA (two cases) (mean age at operation; seventy), with a minimum followup of two years. In revision cases, we attached greater trochanter to proximal femur fixing like figure eight with this tape. Migration of greater trochanter, union rate, pain and dislocation were evaluated in this study. Result: Bone union was achieved without migration and we did not experience any patients with pain. However migration of greater trochanter to cranially and anteriorly 3mm was observed in all re-revision cases. A patient dislocated twice after the re-revision. Discussion: We demonstrated that the polyethylene tape had several advantages used in greater trochanter fixation. Strength of the polyethylene tape has been reported as strong as the stainless cable. The polyethylene tape did not cause any adverse effects including pain and cheese cut phenomenon because of broad contact area with bone. The tape could be put directly on the stem, which is impossible with metal wires and cables. In addition, we do not expect any third body wear. We concluded that polyethylene tape applied for fixing greater trochanter in revision THA would be safe and effective

We retrospectively reviewed the mid term outcome of 88 MoM THA in 84 patients and 21Hip Resurfacing using Recap Magnum bearing surface performed during 2006 – 2009. There were 41 males and 47 females in the THA group and 17 males and 4 females in the Hip Resurfacing group. All procedures were performed through a posterior approach. The average head size for the THR group was 46mm and the cup size was 52mm and the average head size for the resurfacing was 50mm and cup size was 56mm respectively. Median age for the THA group was 60 yrs. (28–73) and for the Resurfacing it was 51.5 yrs. (32–62). Average follow up was 76 months for the THA group and 78 months for the Resurfacing group. Average serum cobalt for the THA and the Resurfacing groups were 53.2nmol/l (119) and 30.85 and the Chromium levels were 82.44nmol/l(134.5) and 67.49 respectively. Eight MRI scans showed abnormal fluid collections suspicious of ARMD in the THA group and 2 showed fluid collection in the Resurfacing group. There were five revisions in the THA group with the tissue diagnosis of ALVAL. In all except one case a well fixed uncemented stem (Taperloc) was retained. In our series Recap Magnum on a Taperloc stem showed 94% survival at five years and therefore we continue to review the cases annually with serum cobalt chromium levels and MRI scans

This study presents an unusual recurrent case of pigmented villonodular synovitis (PVNS) around a ceramic-on-metal (COM) hip retrieved at 9-years. PVNS literature relates to metal-polyethylene and ceramic-ceramic bearings. Amstutz reported 2 cases with MOM resurfacing and Xiaomei reported PVNS recurring at 14 years with metal-on-polyethylene THA. Friedman reported on PVNS recurrence in a ceramic THA. Ours may be the first reported case of recurrent PVNS of a ceramic-on-metal articulation. This young female patient (now 38-years of age) had a total hip replacement in 2006 for PVNS in her left hip. In her initial work-up, this case was presumed to be a pseudotumor problem, typical of those related to CoCr debris with high metal-ion concentrations. She had an CoCr stem (AML), 36mm Biolox-delta head (Ceramtec), and a Pinnacle acetabular cup with CoCr liner (Ultramet, Depuy J&J). This patient had no concerns regarding subluxation, dislocation or squeaking. Three years ago she complained of mild to moderate groin and thigh pain in her left hip. This worsened in the past year. She noticed increased swelling now with an asymmetry to her right hip. She went to the emergency room in Dec-2014 and was referred to a plastic surgeon. In our consult we reviewed MARS-MRI and CT-scans that demonstrated multiple mass lesions surrounding the hip. Laboratory results presented Co=0.7, Cr=0.3 ESR=38 and Crp=0.3. At revision surgery, the joint fluid was hemorrhagic/bloody with hemosiderin staining the soft tissues. Multiple large 4–5×5cm nodules were present in anterior aspect of the hip as well as multiple nodules surrounding posterior capsule and sciatic nerve. Pathology demonstrated a very cellular matrix with hemosiderin-stained tissue and multiple giant cells, which was judged consistent with PVNS. The trunnion showed no fretting, no contamination and no discoloration. The superior neck showed impingement due to low-inclination cup. There was minimal evidence of metal-debris staining the tissues. There was a large metallic-like stripe across the ceramic head. This is a particularly interesting case and may be the first reported recurrent PVNS around a ceramic-on-metal bearing (COM). Data is scant regarding clinical results of COM bearings and here we have a nine-year result in a young and active female patient. She was believed to have a metalosis-related pseudotumor yet her metal-ion levels were not alarmingly high and there was no particular evidence of implant damage or gross wear products. In addition, the CoCr trunnion appeared pristine. Our work-up continues with analyses of wear and histopath-evidence. This case may demonstrate the need for a broadening of the differential diagnosis when dealing with hip failures

Background:. Hip arthroplasty is very successful in order to alleviate pain and improve health-related quality of life. Health-care costs are constantly growing and the burden of patients with hip disease has increased dramatically. Careful consideration of the patients'need and expectations include not only the proper indication for surgery but also choice of method. Hip resurfacing (HRA) has been popularized during the last decade, being bone conservative, capable to restore the anatomical hip center and lower the risk of dislocation. Some HRA-designs have proven good long-term survival rate while others have shown an unacceptable high amount of loosening and been recalled. Yet, for a selected group of patients HRA may be advantageous to THA regarding health-related quality of life. A fundamental prerequisite understanding today's and tomorrow's request on hip arthroplasty is to measure outcomes from patients' perspectives. In this pilot study we compared the patient-reported outcome measures after hip resurfacing with THA using validated general and hip disease specific instruments. Methods:. A questionnaire was sent to 108 randomly selected patients (72% male) of a cohort of 259 patients (Charnley A+B) who had had uni- or bilateral (two stages) HRA for a period of at least six months. Maximal follow-up time was 7 years. Mean age was 50.2 years (males) and 46.2 years (females) respectively. Patients were reporting EQ-5D and self assessed health-quality (0–100%). In addition, a minor group randomly selected, reported their activity that was graded according to UCLA-activity score. As preoperative EQ-5D baseline, a matched group of 40 patients from the hospital's database scheduled for HRA served. Results:. 92 of 108 questionnaires with EQ-5D and self assessed health quality were complete. The mean postoperative EQ-5D was 0.89 (0.30 preoperative) and self assessed health quality being 59.3% (15–100) preoperatively was 80.2% (40–100) postoperatively. UCLA- activity score was 7.2 (4–9) postoperative. Of the whole group of 259 patients, three patients suffered from nerve palsy (two transient), two early cupmigrations (revised), one psoas-impingement and one AVN with cervical fracture (both revised), one deep infection, one ALTR and one dislocation (high-energy trauma). Conclusion:. Traditional outcome measures often fail to describe outcome from the patients' perspectives. This pilot study, with its limitations, shows that patients' health-related quality of life, as measured with EQ-5D after HRA is comparable to or better than that of THA. Patients with HRA in general seem to reach high activity level. However, adverse reactions to metal debris are escalating and with HRA compared to proven THA-designs the risk of complications, e.g., early loosening, especially in females, is higher. For men, no significant difference in survival rate is reported for HRA compared to THA. Yet, HRA should be considered in subgroups of patients (younger, active men), in order to gain high patient satisfaction

Background: Metal on metal articulation is known to reduce wear and subsequent development of osteolysis. However, long-term results of THA using metal on metal articulation is not well validated, especially in young patients. Methods: Ninety-three THA were performed in 78 patients who were younger than 50 years of age at index surgery. The mean age of the patients was 37 years old. One patient (1 hip) had had a resection arthroplasty due to deep infection, 1 patient (1 hip) had performed stem revision because of periprosthetic fracture and 2 patients died before ten years follow-up and were excluded. Five patients (5 hips) were lost to follow-up before 10 years. Sixty-nine patients (84 hips) were available for complete clinical and radiographic analysis after minimum 10 years follow-up(range, 10 – 14 years). Results: The mean preoperative Harris hip score of 49 points improved to 92 points at the time of last follow-up. Twenty hips(21.5%) showed variable degrees of osteolysis. Three patients underwent revision surgery because of focal pelvic osteolysis in one, aseptic loosening with extensive pelvic osteolysis of acetabular component in two. Three subsidence of femoral stem in other patients were identified. Conclusions: At a minimum 10 years after THA using metal-on-metal articulation, it showed good results with regard to aseptic loosening in this group of young patients. However, relatively high rate of osteolysis in this articulation remains problematic and needs further investigation

Introduction. The safe zone of the acetabular cup for THA was discussed based on the AP X-ray films of hip joints. A supine position is still used to determine the cup position for CAOS such as navigation systems. There were few data about the implant positions after THA in standing positions. The EOS X-Ray Imaging Acquisition System (EOS system) (EOS imaging Inc, Paris, France) allows image acquisition with the patients in a standing or sitting position. We can obtain AP and lateral X-ray images with high-quality resolution and low dose radiation exposure. Recently, we have obtained the EOS system for the first time in Japan. We investigated 3D accuracy of the EOS system for implant measurements after THA. Patients and Methods. We measured the implant angles of the 68 patients (59 females and 9 males, average age: 61y.o.) who underwent THA using the EOS system. The cup inclination and anteversion were measured in the anterior pelvic plane (APP) coordinate. The femoral stem antetorsion was defined as angles between the stem neck axis and the posterior condylar axis. These data were compared with the implant angles of the same patients measured by the post-operative CT scan images and the 3D image analysis using the ZedHip software (LEXI, Japan). Results. The cup inclinations (average ±SE) measured by the EOS system and the CT scan were 40.6 ± 0.64° and 42.9 ± 0.53°, respectively. The cup anteversions were 22.9 ± 1.3° and 22.8 ± 1.0°, respectively. The stem antetorsions were 28.9 ± 1.3° and 29.8 ± 1.6°, respectively. The differences (average ± SE) between the EOS system and the CT scan in the cup inclination, the cup anteversion, and the stem antetorsion were −2.3 ± 0.38°, −0.09 ± 0.82°, and −0.90 ± 0.91°, respectively. There were strong correlations in measurement values between the EOS system and the CT scan (the Spearman's correlation coefficients of the cup inclination, the cup anteversion, and the stem antetorsion were 0.6521 [p<0.001], 0.7154 [p<0.001], and 0.8645 [p<0.001], respectively). Discussion. The EOS system provides acceptable clinical accuracies in measuring acetabular cup and femoral stem angles after THA. The accuracy of the cup angles was accorded with that of the basic experimental data using a dry pelvis. Our data also demonstrated clinically acceptable accuracy in the measurement of stem antetorsion. This system can provide accurate snap shots of variable postures with high resolution. Using the EOS system, we may establish real optimum positions of THA implants by measuring the patients after THA in several postures including standing, squatting or sitting positions which required for Japanese ADL

Background. The development of T-smart tomosynthesis has greatly improved the imaging quality of THA by reducing the peri-implant artifacts. In order to find out whether these improvements could lead to diagnostic advantages on stability of cementless THA arthroplasty components, we conducted a diagnostic research by comparing T-smart tomosynthesis, X-ray, and computed tomography. Methods. We retrospectively included 48 patients who undergone THA revisions in our center between Aug, 2013 and Mar, 2014. For patients with hybrid fixation as their primary prosthesis, the femoral or acetabular components with cement fixation were excluded. There were 41 cementless femoral stems and 35 cementless acetabular cups remained for evaluation. All patients took anterior-posterior and lateral view x-ray examination, anterior-posterior T-smart tomosynthesis scan, and computed tomography before revision surgery. As the gold standard, intraoperative pull-out tests and twisting tests were done for every patient to examine the stability of all implants. 7 orthopedic surgeons evaluated the preoperative images independently, who were divided into the senior group (3 doctors with 6∼13 years’ clinical experience) and the junior group (4 doctors with 2∼4 years’ clinical experience). The x-rays were evaluated first, followed by computed tomography 4 weeks later, and after another 4 weeks’ interval the T-smart tomosynthesis were assessed. All doctors used the same criteria for diagnosis. Diagnostic accuracy for each imaging examination was calculated by comparing with the results of intraoperative tests. The diagnostic accuracy, kappa values between 3 imaging techniques were calculated, and chi-square tests were conducted to examine the difference between the senior and junior groups for each technique. Results. The accuracy of T-smart tomosynthesis on stability diagnosis (loosening or stable) is 82.6% for femoral stem and 84.5% for acetabular cup. The accuracy of X-ray is 44.3% for stem and 67.3% for cup, and the accuracy of CT is 39.6% for stem and 74.6% for cup. The kappa values between the 3 techniques range from −0.053 to 0.22. For plain X-ray, The diagnostic accuracy of the senior group is significantly higher than that of the junior group (p<0.05), but no significance was found between the 2 groups for tomosynthesis and CT. Discussion. Our research indicates that, compared with x-ray and CT, the T-smart tomosynthesis technique can greatly improve the diagnostic accuracy on stability of cementless THA components, and significantly shorten the learning curve of inexperienced surgeons. With T-smart tomosynthesis, the peri-implant trabecular bone can be clearly imaged with least metal artifacts ever. T-smart tomosynthesis is an effective and promising imaging technique for diagnosing the stability of THA components

Introduction. The rate of total hip arthroplasty (THA) surgery continues to dramatically rise in the United States, with over 300,000 procedures performed in 2010. Although a relatively safe procedure, THA is not without complications. These complications include acetabular fracture, heterotopic ossification, implant failure, and nerve palsy to name a few. The rates of neurologic injury for a primary THA are reported as 0.7–3.5%. These rates increase to 7.6% for revision THA. The direct anterior total hip arthroplasty (DATHA) is gaining popularity amongst orthopedic surgeons. Many of these surgeons elect to use the Hana® table during this procedure for optimal positioning capability. Although intraoperative mobility and positioning of the hip joint during DATHA improves operative access, select positions of the limb put certain neurologic structures at risk. The most commonly reported neurologic injuries in this regard are to the sciatic and femoral nerves. To our knowledge, the use of neuromonitoring during DATHA, especially those using the Hana® table, has not been described in the literature. Methods. The patient was a 60-year-old male with long standing osteoarthritis of the right hip and prior left THA. Somatosensory evoked potential (SSEP) leads were placed bilaterally into the hand (ulnar nerve) as well as the popliteal fossae (posterior tibial nerve). Unilateral electromyography leads were placed into the vastus medialis obliquus, biceps femoris, gastrocnemius, tibialis anterior, and abductor hallucis of the operative limb (Fig. 1). Once the patient was sterilely draped, a direct anterior Smith-Peterson approach to the hip was used. Results. After the patient completed standard pre-operative protocol, neuromonitoring leads were placed as described above. There were no complications, neuromonitoring remained stable from baseline, and the patient tolerated the procedure well. Moreover, the senior author routinely uses a prophylactic cable around the calcar, particularly in patients with osteoporotic bone, as was the case with this patient. The patient's post-operative course has been without complications as well. Conclusion. There are a few studies that have examined the pressure changes around the femoral nerve during a DATHA and found that the nerve was at most danger with misplacement of a retractor near the anterior lip of the acetabulum. Furthermore, the popularity of DATHA and the Hana® table make neuromonitoring more amenable for use since the whole limb does not need to be sterilely prepped as with other approaches to the hip. The reported rates of neurologic injury during any THA along with those developed from passage of prophylactic cerclage cables and the goals of reducing surgical complications make this novel technique intriguing. It allows the surgeon yet another safe and effective tool to decrease the likelihood of neurologic injury during DATHA. For any figures or tables, please contact the authors directly

Introduction:. Whole blood metal ion level and clinical outcomes of ceramic-on-metal bearing were comparable to ceramic-on-ceramic THA in this prospective randomized controlled trial. Methods:. We randomized 150 consecutive THA cases at one institution into two groups: Group I and Group II. Group I, 75 cases, received a THA using ceramic-on-metal couplings and Group II, 75 cases, received ceramic-on-ceramic bearing THA. The implant differed only in the bearing surfaces used. We compared the serum levels of cobalt (Co) and chromium (Cr) and functional outcome scores preoperatively, and at 2, 6, and 12 months postoperatively. Results:. The demographics and preoperative Co and Cr levels were similar between the groups. Femoral head size measured 32 and 36 mm and the proportion of each size was similar in both groups. The mean serum cobalt and chromium levels increased significantly at 2 months in Group I (Co p = 0.02, Cr p = 0.04), but no differences noted between groups at 6 and 12 months (Co p > 0.05, Cr p > 0.05). The mean WOMAC hip scores showed comparable improvements at 12 months with no difference between groups. No ceramic fracture has occurred during follow-up period. Discussion & Conclusion:. CoM bearing THA has showed the metal ion levels and the clinical results comparable to CoC couples except for the relatively high metal ion in running-in period

While cemented THA has been considered the gold-standard, cementless THA has become a common and even preferred approach for younger individuals and those with acceptable bone stock. Which technology provides superior results and in which patients, however, remains controversial, and has not been systematically studied. The literature suggests that well-fixed cementless prostheses, and even composite beam cemented prostheses cause stress shielding and progressive osteopenia in the surrounding bone. This compromises and complicates subsequent surgery, particularly in young patients who are at risk for multiple revisions, and may increase the risk of periprosthetic fracture, component failure, and aseptic loosening. In contrast, polished tapered stems, by behaving according to a taper-slip philosophy, favorably load bone, converting shear stress into radially directed hoop stresses, through the medium of the surrounding visco-elastic cement and its resulting ability to creep. The C-Stem, (DePuy, Warsaw, Indiana, USA) a cemented triple tapered polished stem is the only stem with published data demonstrating positive remodeling of bone in as many as 20% of patients, and preservation of the critical proximal medial calcar bone. Additional anectdotal reports confirm these results. The long-term results of cemented stems, which necessarily involve the surviving youngerst cohort in any series, are outstanding. The tapered polished stem technology may improve these historical results, and, by limiting periprosthetic stress shielding and osteopenia, may revolutionize the application of cemented THA in younger patients for whom preservation of bone stock through favorable bone loading is so critical to sustained success of the primary and subsequent revision surgeries

Introduction. IBBC (interfacial bioactive bone cement method, Oonishi) (1) is an excellent technique for augmenting cement-bone fixation in the long term. However, the technique is difficult and there are concerns over some points, such as bleeding control, disturbance of cement intrusion to anchoring holes by granules, difficulty of the uniform granular dispersion to the acetabular bone (Zone 1 in particular). To improve this technique, we have modified IBBC (M-IBBC), and investigated the short-term clinical results and radiographic changes. Materials and Methods. K-MAX HS-3 THA (Kyocera Medical, Japan), with cemented stem and all polyethylene cemented socket, was used for THA implants. Basically the third generation cementing technique was used for THA using bone cement. The socket fixation was performed with bone cement (Endurance, DePuy) and hydroxyapatite (HA) granules (Ca10(PO4)6(OH)2, Boneceram P; G-2, Olympus, Japan). In original IBBC technique, HA granules were dispersed on reamed acetabulum before cementing. In M-IBBC technique, HA granules were attached to bone cement on plastic plate, then inserted to reamed acetabulum and pressurized. HA granules (G-2) are 0.3–0.6mm in size, with 35–38% porosity and sintered at 1150â��. 51 hip joints (49 cases) were operated between June 2010 and December 2011, and followed. The average follow-up was 3.9 years, and average age at operation was 66.5 years. The clinical results were evaluated by Japan Orthopaedic Association Hip Score (JOA score), and X-p findings were evaluated using antero-posterior radiographs. The locations of radiolucent lines were identified according to the zones described by Delee and Charnley for acetabular components, and Zone 1 was divided into two parts, outer Zone 1a and inner Zone 1b. Results and Discussion. Revision was not performed. Japanese orthopaedic association (JOA) score improved from 48 to 87. Socket and stem loosening was not observed. X-p findings of sockets demonstrated radiolucent line in Zone 1a/1b/2/3 in 2/0/0/0% immediately after the operation, 9.8/2/0/2% at 1 year postoperatively. After 1 year there was no progressive change, however, improvement of radiolucent line in Zone 1a was observed in two cases after 3 years postoperatively. Accordingly, after 3 years radiolucent line in Zone 1a/1b was observed in 5.9/2%. Oonish has reported excellent clinical results of THA with IBBC (1). To easily perform IBBC, we have modified the technique, improving the problems of IBBC. In our previous report, we reported improvement of radiolucent line in IBBC (2). In this report, the similar radiographic behavior was observed in M-IBBC, which was not observed in conventional cementing technique. This finding suggests osteoconductive property of hydroxyapatite granules at the interface after the operations. Conclusions. The interesting finding in M-IBBC cases was the improvement of radiolucent line, which was observed in IBBC cases. The promising long-term clinical results of M-IBBC method, similar to IBBC cases, were expected

Introduction. We developed original KKS non-cement THA system and used clinically over 10 years. KKS means Keio Kyocera Series. This system was developed co-ordinating with Keio-University and Kyocera Company in Japan. Our concept was to make original THA system suitable for Japanese people. Osteoarthritis of the hip in Japanese people caused mainly from developmental dysplasia of the hip. So the shape of femoral medullary canal is characteristic compared with foreign patients. We analyzed the femoral medullary canal shape in typical Japanese osteoarthritis 50 cases of the hip by the use of CT scan. From the results of these analyses, we determined the optimal shape of KKS non-cement stem for Japanese patients. It has double tapered shape in distal stem shaft. Proximal taper angle of the stem is 4 degree, and distal one is 3 degree. The proximal part of stem has characteristic notch in anterior and posterior and lateral surface to tolerate rotational stability. Objectives. We evaluated long terms results (over 10 years) of KKS original stem mainly radio graphically and estimate the usefulness. Methods. We started to use porous HA coated KKS stem from 1995. From 1995 to 1998 this stem was applied for 73 cases of non-cement THA in Keio-University. Excluding 2 cases of infection and stem breakage, 55 of 71 cases could be followed over 10 years (follow-up rate: 75%). In these 55 cases, average age at THA operation was 54 (24–64) years old and mean follow-up time was 11.2 (10–13) years. Radiographic findings in 55 cases at follow-up time were evaluated, concerning about following points: stem sinking, loosening, spots-welds, calcar resorption, and osteolysis on femoral side. Results. No sinking and no loosening of the stem were seen. Calar resorption was seen in 22 cases: 40%. Spot-welds was seen in almost cases on 51/55:92%. Osteolysis was seen in 9 cases, zone1;1 case, zone 7;8 cases. Clinical results were excellent as radiographic results. Conclusions. The aim to develop this system is to make optimal shape stem suitable for Japanese patients. Optimal fitting in the femoral medullary canal by KKS stem was confirmed on X-P. High occurrence rate of spot-welds showed strong stability to bone. On X-ray evaluation, no stem sinking and no loosening were found at over 10 years after operation. It proved the enough biological fixation to bone for a long time. But osteolysis occurred in 9 cases. This may come from the use of conventional polyethylene socket. Now cross-linked polyethylene socket is used and the wear of socket is expected to reduce. Off course longer follow-up of KKS system is needed. But the evaluation of KKS stem at 10 years follow-up indicated enough usefulness

Aims

The aims of this study were to determine the success of a reconstruction algorithm used in major acetabular bone loss, and to further define the indications for custom-made implants in major acetabular bone loss.

Aims

The risk factors for abnormal spinopelvic mobility (SPM), defined as an anterior rotation of the spinopelvic tilt (∆SPT) ≥ 20° in a flexed-seated position, have been described. The implication of pelvic incidence (PI) is unclear, and the concept of lumbar lordosis (LL) based on anatomical limits may be erroneous. The distribution of LL, including a unusual shape in patients with a high lordosis, a low pelvic incidence, and an anteverted pelvis seems more relevant.

Introduction. We have compared the middle-term (average follow-up period; 10 years) clinical results of the K-MAX HS-3 tapered stem with those of the previous type having cylindrical tip. Materials and Methods. In K-MAX HS-3 THA (Kyocera Medical, Kyoto, Japan), cemented titanium alloy stem and all polyethylene cemented socket are used. This stem has the double tapered symmetrical stem design, allowing the rotational stability and uniform stress distribution (Type T) (Fig. 1). The features of this stem are; 1. Vanadium-free high-strength titanium alloy (Ti-15Mo-5Zr-3Al), 2. Double-tapered design, 3. Smooth surface (Ra 0.4μm), 4. Broad proximal profile, 5. Small collar. In contrast, previous type stem, which was made of the same smooth-surface titanium alloy, has the design with cylindrical stem tip, allowing the maximum filling of the femoral canal (Type C) (Fig. 2). Osteolysis at the distal end of the stem had been reported in a few cases in Type C, probably due to the local stress concentration. Therefore the tapered stem was designed, expecting better clinical results. All surgery was performed at Kitano Hospital between September 2003 and June 2006. 72 THA were performed (Type T; 52 hips, Type C; 20 hips). The average age of the patients at the operation was 61 and 69 years and the average follow-up period was 10.1 and 10.4 years for the Type T and C, respectively. The all-polyethylene socket was fixed by bone cement, and the femoral head material was alumina or CoCr (22 or 26 mm). Results. One hip was revised in Type C. Japanese orthopaedic association (JOA) score improved from 39/37 to 84/77 points (Type T/C). Postoperative complication was dislocation in one case (Type C; 1). Socket loosening was not observed radiographically. Stem loosening was observed in one hip in Type C, demonstrating osteolysis at the distal end of the stem. In this case, revision THA was performed 3.5 years postoperatively. Bone resorption was more frequently observed in Type C than Type T. Cortical hypertrophy was observed in 7.7% in Type T and 25% in Type C. Discussion. The middle-term clinical results of K-MAX HS-3 taper stem (Type T) was excellent. The osteolysis at the stem tip was not observed in this type, which was observed in a few cases in previous Type C. From the X-ray finding, it was suggested that Type T had more uniform stress distribution to the femoral bone than Type C. Moreover, the problems associated with titanium alloy usage were not observed. From the present investigation, good long-term results of the tapered titanium stem (Type T) was expected. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Introduction Modern metal-on-metal hip resurfacing (RHA) was introduced as a bone-preserving method of joint reconstruction for young and active patients; however, the large diameter of the bearing surfaces is of concern for potentially increased metal ion release. Patients and methods 71 patients (< 65 yrs) were randomly assigned to receive either a RHA (n=38) or a conventional metal-on-metal (MoM) THA (n=33). Functional outcomes were assessed preoperatively, at 6, 12 and 24 months. Cobalt and chromium blood levels were analyzed preoperatively, at 3, 6, 12 and 24 months. Results All functional outcome scores improved highly significant for both groups. At 12 and 24 months the UCLA Activity score was significantly higher for the RHA patients, the OHS only at 24 months. However, in spite of randomization UCLA scores also appeared to be higher in RHA patients at baseline. RHA patients were more satisfied at 12 months. Cobalt concentrations were significantly higher for RHA only at 3 and 6 months. Chromium levels remained significantly higher for RHA until 24 months. No pseudotumors were encountered in either group so far. One RHA was revised for early aseptic loosening and in two THA's a cup insert was exchanged for recurrent dislocation. Conclusion RHA patients scored significantly higher on UCLA, OHS and satisfaction at some intervals, however, as for the UCLA preoperative levels were already in favor of RHA. Chromium blood levels were significantly higher for RHA, whereas for cobalt this was only observed up to 6 months. The true value of RHA against THA will be determined by longer follow-up and a possible shift of balance between their respective (dis)advantages

Previous clinical studies have documented the incidence of squeaking in subjects having a ceramic-onceramic (COC) THA. An in vivo sound sensor was recently developed used to capture sound at the THA interface. In this first study, it was determined that subjects having all bearing surface types demonstrated variable sounds. Therefore, in this follow-up study, the overall objective was to simultaneously capture in vivo sound and motion of the femoral head within the acetabular cup during weight-bearing activities for subjects implanted with one of four different ceramic-on-ceramic (COC) THA. Twenty subjects, each implanted with one of four types of Ceramic-on-Ceramic THA (9 Smith and Nephew, 8 Stryker, 2 Wright Medical Technologies and 1 Encore) were analyzed under in vivo, weightbearing conditions using video fluoroscopy and a sound sensor while performing gait on a treadmill. Patients were pre-screened and two groups were defined: a group diagnosed as audible squeakers (9 THAs) and a control group of THA patients not experiencing audible sounds (11 THAs). Two tri-axial piezoelectric accelerometers were attached to the pelvis and the femoral bone prominences respectively. The sensors detect frequencies propagating through the hip joint interaction. Also, 3D kinematics of the hip joint was determined, with the help of a previously published 2D-to-3D registration technique. In vivo sound was then correlated to 3D in vivo kinematics to determine if positioning of the femoral head within the acetabular cup is an influencing factor. For the audible group, two had a Smith and Nephew (S& N) THA, six a Stryker THA and one a Wright Medical (WMT) THA. Both of the S& N subjects, 5/6 Stryker and the Wright Medical subjects experienced femoral head separation. The maximum separation for those subjects was 4.6, 5.0 and 2.1 mm for the S& N, Stryker and WMT subjects, respectively. The average separation was 4.3, 2.0 and 2.1 mm for the S& N, Stryker and WMT subjects, respectively. For the eleven subjects in the control group, seven subjects had a S& N THA, two a Stryker and one each having a WMT and Encore THA. All 11 of these subjects demonstrated hip separation with the maximum values being 3.8, 3.4, 1.9 and 2.4 mm for the S& N, Stryker, WMT and Encore THA, respectively. The average separation values were 1.8, 2.3, 1.9 and 2.4 mm for the S& N, Stryker, WMT and Encore THA subjects, respectively. Four distinct sounds were produced by subjects in this study, which were squeaking, knocking, clicking and grating. Only 3/20 subjects produced a “squeaking” sound that was detected using our sound sensor. One of these subjects had a Stryker THA and two had a WMT THA. Further analysis of the nine subjects who were categorized as audible squeakers revealed that only 0/2, 1/6 and 1/1 subjects having a S& N, Stryker and WMT THA, respectively, demonstrated a squeaking sound that was detected using our sound sensor. Both (2/2) S& N subjects demonstrated a knocking and clicking sound, but neither produced a grating sound, while 5/6 Stryker subjects produced a knocking sound, but only 1/6 demonstrated a clicking or grating sound. Besides the squeaking sound, the only other sound produced by the WMT audible squeaker was a knocking sound. Only 1/11 control group subjects demonstrated a squeaking sound, which was a subject having a WMT THA. With respect to the control group subjects having a S& N THA, 5/7, 1/7 and 3/7 subjects produced a knocking, clicking or grating sound, respectively. Only 1/2 subjects having a Stryker THA produced a knocking or grating sound. This is the first study to compare multiple COC THAs in analyzing correlation of femoral head separation (sliding) and sound. It was seen that all the THA groups had occurrences of separation and each case of separation correlated with the sound data. These results lead the authors to believe that the influence of squeaking is multi-factorial, and not necessarily attributed only to the bearing surface material

Introduction. Optimal implant position is the important factor in the hip stability after THA. Both the acetabular and femoral implants are placed in anteversion. While most hip dislocations occur either in standing position or when the hip is flexed, preoperative hip anatomy and postoperative implants position are commonly measured in supine position with CT scan. The isolated and combined anteversions of femoral and acetabular components have been reported in the literature. The conclusions are questionable as the reference planes are not consistent: femoral anteversion is measured according to the distal femoral condyles plane (DFCP) and acetabulum orientation in the anterior pelvic plane (APP)). The EOS imaging system allows combined measurements for standing position in the “anatomical” reference plane or anterior pelvic plane (APP) or in the patient “functional” plane (PFP) defined as the horizontal plane passing through both femoral heads. The femoral anteversion can also be measured conventionally according to the DFCP. The objective of the study was to determine the preoperative and postoperative acetabular, femoral and combined hip anteversions, sacral slope, pelvic incidence and pelvic tilt in patients who undergo primary THA. Material and Methods. The preoperative and postoperative 3D EOS images were assessed in 62 patients (66 hips). None of these patients had spine or lower extremity surgery other than THA surgery in between the 2 EOS assessments. None had dislocation within the follow up time period. Results. Pelvic values. The preoperative sacral slope was 42.4°(11° to 76°) as compared to the postoperative sacral slope (40.3°, −4° to 64°)(p=0.014). The preoperative pelvic tilt was 15.3° (−10° to 44°) as compared to the postoperative tilt (17.2°, −6° to 47°)(p=0.008). The preoperative pelvic incidence was 57.7°(34° to 93°) and globally unchanged as compared to the postoperative incidence (57.5°, 33° to 79°)(p=0.8). Acetabular values. Surgeons increased the anteversion according to the APP by an average of 12.6°(−13° to 53°)(p<0.001). Acetabular anteversion was increased by 14.3° in the PFP (−11° to 51°)(p<0.001). Femoral values. In the DFCP, preoperative neck anteversion was decreased postoperatively by an average of −3,2°(−48° to 33°)(p=0,0942). In the PFP, preoperative neck anteversion was decreased postoperatively by an average of −6,3°(−47° to 17°)(p<0,001). Combined values. According to the classical methods (acetabular orientation in the APP and femoral anteversion in the DFCP), mean preoperative combined anteversion was 36.1° (4° to 86°) and was increased postoperatively to 45.5°(−12° to 98°)(p=0.0003). According to the PFP, mean preoperative combined anteversion was 30,7°(5° to 68°) and was increased postoperatively to 38,8°(−10° to 72°)(p=0,0001). Conclusion. This study reports two methods for the measurement of acetabular and femoral anteversion, “anatomical” according to the APP and DFCP and “functional” according to the PFP. Surgeons tend to increase the anteversion of the acetabular implant and to decrease femoral anteversion during the surgery. The trend is the same for postoperative evolution of values using the “anatomical” or the “functional” methods but numerical discrepancies are explained by significant APP orientation changes. The assessment of the true combined anteversion provides new perspectives to optimize our understanding of THA stability and function

Introduction. The current recommendation by the AAOS in the 2010 clinical practice guidelines for the use of MRI to diagnose a periprosthetic joint infection (PJI) is “inconclusive” given the lack of evidence to support its use. The purpose of this study was to determine the utility of MRI with metal reduction artifact sequencing in diagnosing a periprosthetic joint infection (PJI) after total hip arthroplasty (THA). Methods. 176 patients who underwent MRI with multi-acquisition variable resonance image combination (MAVRIC) to reduce metal artifact for a painful THA between the years of 2009–2013 were retrospectively evaluated. All MRIs were read by one of four radiologists with extensive experience in interpreting MRIs after THA. All MRIs were performed using a 1.5 Tesla magnet. Of the 176 patients examined, 16 patients were found to have a deep periprosthetic joint infection using Musculoskeletal Infection Society (MSIS) criteria after the MRI was performed. MRI reads were classified as either positive (read as “evidence of active infection” or “suspicious for infection”) or negative (read as no evidence of infection). Only one patient who had a positive MRI read was excluded because of loss to followup after the MRI was performed. Results. Of the 160 aseptic patients, only one patient was read as suspicious for infection (false positive rate = 0.6%, specificity=99.4%, negative predictive value (NPV)=98.8%). Of the 16 patients with an infected THA, 14 patients were read as positive for infection (false negative rate=12.5%, sensitivity = 87.5%, positive predictive value (PPV)=93%). Conclusion. MRI with metal reduction artifact sequence is a highly specific test to diagnose or rule out a PJI with a low false positive rate and excellent PPV and NPV however, given its lower sensitivity than published for the serum C-reactive protein, is not recommended as a general “screening” test for all patients with pain after THA to rule out infection

Background. The goal of total hip arthroplasty (THA) is to reduce pain, restore function but also activity levels for general health benefits or social participation. Thus evaluating THA patient activity can be important for diagnosis, indication, outcome assessment or biofeedback. Methods. Physical activity (PA) of n=100 primary THA patients (age at surgery 63 ±8yrs; 49M/51F; 170 ±8cm, 79.8 ±14.0kg) was measured at 8 ±3yrs follow-up. A small 3D accelerometer was worn for 4 successive days during waking hours at the non-affected lateral upper leg. Data was analysed using validated algorithms (Matlab) producing quantitative (e.g. #steps, #transfers, #walking bouts) and qualitative (e.g. cadence, temporal distribution of events) activity parameters. An age matched healthy control group (n=40, 69 ±8yrs, 22M/18F) served as reference. Results. Daily steps were only 13% lower (n.s) for patients (avg. ±SD: 5989 ±3127) than controls (6890 ±2803). However, the Nr. of walking bouts (187 ±85 vs 223 ±78, −16%) and sit-stand transfers (35 ±14 vs 48 ±15, −27%) were sign. less in patients (p<0.05, Mann-Whitney). Patients showed equal amounts of walking bouts in medium duration (30-60s, 1–5min) but sign. less (−25%) short (<10s, 10–30s) and less (−43%) long events (>5min). This corresponds with sign. less (−32%) short sitting periods (>10min) in patients. Also cadence was sign. lower in patients (93.8 ±11.7 vs 98.9 ±7.3 steps/min). Conclusions. PA varies widely in patients with a substantial proportion (35%) being more active than average controls. Thus, THA must not per se reduce or limit PA. Only 17% of controls and 11% of patients reached the WHO target (10,000 steps/day) suggesting that the THA related drop in activity may inflate the risks for cardiovascular, metabolic or mental disease associated with low activity. Patients avoided short and long activities, both associated with effort. Targeted interventions may address this behaviour

Perioperative fracture during routine THA represents one of the “not so fresh” feelings that occur for both patients and surgeons. With the increase in the use of uncemented implants and MIS techniques this truly is a problem on the rise. We have examined and quantified the risk factors associated with proximal femoral fracture during THA. Risk factors (risk ratios) identified were: uncemented stems (8.9), anterolateral approach (7.4) and female gender (2.2). Fortunately, treatment with cerclage wiring for uncemented stems has facilitated excellent stem stability and acceptable survivorship with many different femoral component designs. Reduced proximal geometry stems that better match the endosteal osseous anatomy have reduced fracture rates at our institution and maintained excellent stem survivorship. New data examining this design will be presented. In our series, cemented stems, however, had decreased survivorship in the presence of a proximal femoral fracture. MIS techniques may accelerate rehabilitation but they certainly permit limited visibility of the proximal femoral and acetabular anatomy and may result in less accurate component position. Relatively high fracture rates in series of MIS-THA have been reported. A bigger concern, however, is the unrecognised fracture that displaces postoperatively and requires a return to surgery for treatment with or without revision and mandates that we “see it before it sees us!” Cerclage wiring with looped Luque wires has been our treatment of choice for many years. Wires are significantly less expensive than cables and have proven to be durable in our series. This technique allows intraoperative repositioning and variable tightening in multiple locations. Cable fretting and breakage have been common in our experience with braided cable devices. Acetabular fracture during uncemented THA is most likely an under-reported occurrence and has been associated with elliptical component designs and under-reaming. In the presence of a stable cup, long-term performance has been acceptable

Introduction. Improvements in function after THA can be evaluated using validated health outcome surveys but studies have shown that PROMs are unreliable in following the progress of individuals. Formal gait lab analysis is expensive, time consuming and fixed in terms of location. Inertial Measurement Units (IMUs) containing accelerometers and gyroscopes can determine aspects of gait kinematics in a portable package and can be used in the outpatient setting (Figure 1). In this study multiple metrics describing gait were evaluated pre- and post THA and comparisons made with the normal population. Methods. The gait of 55 patients with monarthrodial hip arthrosis was measured pre-operatively and at one year post-surgery. Patients with medical co-morbidity or other condition affecting their gait were excluded. Six IMUs aligned in the sagittal plane were attached at the level of the anterior superior iliac spines, mid-thigh and mid-shank. Data was analysed using proprietary software (Figure 2). Each patient underwent a conventional THA using a posterolateral approach. An identical test was performed one year after surgery. 92 healthy individuals with a normal observed gait were used as controls. Results. In the pre-operative test the range of movement in the sagittal plane of both the ipsilateral hip (mean range 20.4) and the contra-lateral non-diseased hip (35.3 degrees) was reduced compared to the control group (40.5 degrees), (P<0.001). The pre-operative range of motion of both knees was also reduced compared with normal (P<0.001). Pelvic movement on the ipsilateral side was increased. After one year the range of movement of the ipsilateral hip significantly improved (Mean range 28.9 deg SD 6.6) but did not attain normal values (P<0.001). Movement measured in the contralateral hip reduced further from its pre-operative value with a mean difference of −5.25 degrees (95% CI −8.06 to −2.43). Measurements of the symmetry of movement were increased. Knee movement on both sides increased but not to normal values (p<0.001). In contradistinction, there was bilateral increased coronal movement at the thigh and calf a year after surgery. Discussion and Conclusion. Gait after routine THA does not return to normal on the ipsilateral or contralateral side. Pathology in one hip causes bilateral gait abnormality that can be quantified by movement at the pelvis, hip, thigh and knee. The ability of a patient to walk normally after surgery will depend on many factors including details of the hip operation such as accurate recreation of the biomechanics of the joint and physical therapy regimens. Advances in technology now allow assessment of gait in large number of patients in the clinic setting and will better allow us to establish the important factors to improve patients gait and thereby potentially improve further satisfaction and PROMS scores. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Introduction. According to the literature, the gait does not return to normal after THA. However, the three-dimensional hip anatomy is usually not assessed before and after surgery. Our hypothesis was that an accurate reconstruction of the hip anatomy, based on a three-dimensional preoperative planning, may normalize the gait after THA. Material and method. 18 consecutive patients, graded Charnley A, aged of 59.3 ±13 years, underwent THA for unilateral primary osteoarthritis using a direct anterior minimal invasive approach. A 3D computerised planning was performed, the implants size and position were chosen in order to restore, the leg length, the off-set, the centre of rotation and the anteversion angles (Figure 1). At 1 year follow up, a 3D gait analysis was performed and included 29 parameters describing the kinetics and the kinematics. Each patient was compared to himself using the contra-lateral healthy hip, as well as to a group of 13 healthy volunteers. Results. The real implants were the same than the ones planned in all the patients. The hip anatomy was restored with a high accuracy: 0.1±3mm for the hip rotation centre, −1.4±3 mm for the leg length and −0.9±3.5mm for the femoral offset. With respect to the gait, there was no significant difference between the operated side and the control-lateral leg. When compared to the control group, all the patients were within the normal range for all the parameters (Figure 2). Discussion and conclusion. The results suggest that the combination of an accurate 3D reconstruction and a direct anterior minimal invasive approach may allow to achieve a normal gait after THA at one year follow up

The Dall approach is a modified anterolateral approach with osteotomy of the anterior part of the greater trochanter. This approach relatively preserves the soft tissue tension during total hip arthroplasty (THA). We insert the stem and select a ball neck size so as to have a stable hip which will not dislocate easily during the trial reduction. The aim of this study is to evaluate the adequacy of this method, to measure leg length discrepancy and offset discrepancy at postoperative radiographs. We selected patients for inclusion in this study from those who have more than a 120 degree of affected hip flection angle, the opposite hip is almost normal with a low leg length discrepancy (primary OA, osteonecrosis, Crowe 1 secondary OA, femoral neck fracture). All THA were performed with cement fixation using an alignment guide to ensure accurate acetabular positioning. The ball head's diameter used were all 26mm. From September 2011 to October 2013, 22 patients met inclusion criteria among 103 THA. The mean age for 22 subjects was 66.6±12 years. The mean flexion angle of preoperative hip joints was 127.2±6.1 degrees. The cup inclination was 43.8° ± 3.5°. Anteversion was 11.8°±6°. The mean preoperative leg length discrepancy was 5.8mm±6.3mm. The mean postoperative leg length discrepancy was 0.7±3.5mm. The mean postoperative offset discrepancy was 0.7±6.6mm. There were no dislocations in this series of 103 cases. Discussion. Dislocation and leg length discrepancies are major complications following a total hip arthroplasty. A good range of motion of the preoperative hip joint is considered a high risk dislocation factor. The Dall approach with minimal release of soft tissue related to a tension of hip joint offers maximal stability and the ability to accurately restore leg length

Several design principles were considered paramount when the surgical technique of performing total hip arthroplasty through an incision in the superior capsule without dislocation of the hip joint was developed. These design principles include: Preservation of the abductors; Preservation of the posterior capsule and short external rotators; Preparation of the femur in situ without dislocation of the hip; In-line access to the femoral shaft axis; Ability to perform a trial reduction; Independence from intraoperative imaging; Independence from a traction table; Applicable to at least 99% of THA procedures. Personal experience with more than 1950 THA using the superior capsulotomy technique over a 12-year period has demonstrated several observations: Dislocation rate of 0.15% (3 in 1950); Acute deep infection rate of 0% (0 in 1950); Universal applicability: used in 99.7% of primary THA; Lateral femoral cutaneous nerve palsy incidence: 0/1950; Femoral nerve palsy incidence: 0/1950; Transient peroneal palsy incidence: 2/1950; Length of stay (since 2010): 1.55 days; Discharge to home: 98%; 90-day cost (2/13 to 2/14) compared to other exposures in CMS patients in the same institution: $24,200 vs $30,100; Readmission costs (CMS 2/13 to 2/14) at 90 days: $0. Conclusion: Performing total hip arthroplasty without dislocation and with preservation of the abductors, posterior capsule and short external rotations has proven to have a low dislocation rate, a low infection rate, and wide applicability. CMS 12-month expenditure data documenting ZERO dollars spent on readmission for any reason within 90 days of surgery demonstrates the potential for simultaneously improving incomes and reducing cost, with particular benefit within the CMS BPCI and private bundled payment programs

Aims

When performing revision total hip arthroplasty using diaphyseal-engaging titanium tapered stems (TTS), the recommended 3 to 4 cm of stem-cortical diaphyseal contact may not be available. In challenging cases such as these with only 2 cm of contact, can sufficient axial stability be achieved and what is the benefit of a prophylactic cable? This study sought to determine, first, whether a prophylactic cable allows for sufficient axial stability when the contact length is 2 cm, and second, if differing TTS taper angles (2° vs 3.5°) impact these results.

Introduction. Resorptive bone remodeling secondary to stress shielding has been a concern associated with cementless total hip arthroplasty (THA). At present, various types of cementless implants are commercially available. The difference in femoral stem design may affect the degree of postoperative stress shielding. In the present study, we aimed to compare the difference in bone mineral density (BMD) change postoperatively in femurs after the use of 1 of the 3 types of cementless stems. Methods. Ninety hips of 90 patients who underwent primary cementless THA for the treatment of osteoarthritis were included in this study. A fit-and-fill type stem was used for 28 hips, a tapered-rectangular Zweymüller type stem was used for 32 hips, and a tapered-wedge type stem was used for 30 hips. The male/female ratio of the patients was 7/21 in the fit-and-fill type stem group, 6/26 in the tapered-rectangular Zweymüller type stem group, and 6/24 in the tapered-wedge type stem group. The mean age at surgery was 59.9 (39–80) in the fit-and-fill type stem group, 61.7 (48–84) in the tapered-rectangular Zweymüller type stem group and 59.6 (33–89) in the tapered-wedge type stem group. To assess BMD change after THA, we obtained dual-energy X-ray absorptiometry scans preoperatively and at 6, 12, 24, and 36 months postoperatively. Results. There were no differences in demographic data, such as gender, age at surgery, and body mass index, among the 3 groups (Table1). In terms of BMD change after THA, no differences were observed in Gruen zones 1–5 among the 3 groups during the 3-year follow-up. The BMD in Gruen zone 6 was maintained in the tapered-wedge type stem group, but decreased by 5% in the fit-and-fill type stem group and by 20% in the tapered-rectangular Zweymüller type stem group (p < 0.01). The BMD loss in Gruen zone 7 was observed in all stem types; however, the BMD loss at 36 months in the tapered-wedge type stem group (−15%) was significantly less than that of the other 2 groups (the fit-and-fill type stem group: −29%; the tapered-rectangular Zweymüller type stem group: −30%; p < 0.001 for both groups) (Figure). Discussion and Conclusion. A difference in postoperative BMD loss was observed among the 3 stem designs. This may be a result of the different fixation concept associated with each stem design. In the present study, we compared the postoperative BMD change after THA among a fit-and-fill type stem, a tapered-rectangular Zweymüller type stem, and a tapered-wedge type stem. BMD in the medial-proximal femur was maintained 3 years after THA in the group with the tapered-wedge type stem, which is fixed in a more proximal part of the femur compared to the other stems

Introduction. The current recommendation by the AAOS in the 2010 clinical practice guidelines for the use of MRI to diagnose a periprosthetic joint infection (PJI) is “inconclusive” given the lack of evidence to support its use. The purpose of this study was to determine the utility of MRI with metal reduction artifact sequencing in diagnosing a periprosthetic joint infection (PJI) after total hip arthroplasty (THA). Methods. 176 patients who underwent MRI with multi-acquisition variable resonance image combination (MAVRIC) to reduce metal artifact for a painful THA between the years of 2009–2013 were retrospectively evaluated. All MRIs were read by one of four radiologists with extensive experience in interpreting MRIs after THA. All MRIs were performed using a 1.5 Tesla magnet. Of the 176 patients examined, 16 patients were found to have a deep periprosthetic joint infection using Musculoskeletal Infection Society (MSIS) criteria after the MRI was performed. MRI reads were classified as either positive (read as “evidence of active infection” or “suspicious for infection”) or negative (read as no evidence of infection). Only one patient who had a positive MRI read was excluded because of loss to followup after the MRI was performed. Results. Of the 160 aseptic patients, only one patient was read as suspicious for infection (false positive rate = 0.6%, specificity=99.4%, negative predictive value (NPV)=98.8%). Of the 16 patients with an infected THA, 14 patients were read as positive for infection (false negative rate=12.5%, sensitivity = 87.5%, positive predictive value (PPV)=93%). Conclusion. MRI with metal reduction artifact sequence is a highly specific test to diagnose or rule out a PJI with a low false positive rate and excellent PPV and NPV however, given its lower sensitivity than published for the serum C-reactive protein, is not recommended as a general “screening” test for all patients with pain after THA to rule out infection

Consecutive patients undergoing primary THA were consented from the practices of 3 arthroplasty surgeons. One surgeon performed all DAA THA's, the other two surgeons performed all posterior THA's. All patients received a similar design of uncemented acetabular and femoral components and were managed with similar pain management and rehabilitation protocols. One hundred twenty patients (60 patients per group) with similar age, sex and BMI as well as similar pre-operative health and function scores were followed. Functional recovery was faster in patients with DAA on the basis of TUG and M-FIM assessed on post-operative days 1, 2, 3 but only TUG remained different at 2 weeks. No differences in TUG, M-FIM, UCLA & Harris Hip scores, SF-12 scores, were observed between the groups at 6 and 12 weeks. Comparison of visual analogue pain scores, LOS, time to return to activities of daily living and surgical complexity also revealed no significant differences. DAA offered a faster post-operative recovery after primary THA compared to the PA. Equivalence was achieved somewhere between 2- and 6-weeks post-operatively. Gait analysis comparisons reveal similar kinematic gains in the frontal and sagittal planes, with increased motion in the transverse plane with DAA at 6 months. Individual muscle testing showed persistent ER weakness with posterior hips at 3 months

There has been great enthusiasm over the last few years for the mini-anterior, or, the Direct Anterior (DA) approach. As the title of this session suggests there is a perception that there are features of this approach that result in an unusually rapid recovery with “early” return to a high level of function. There have also been claims of improved implant placement and limb length restoration. This is presumably a result of the use of intra-operative imaging. When originally described, it was stated that the DA permitted THA “without cutting any tendons.” The implication was that the alleged unique recovery was due to this particular feature. Over the last decade I have used a trans-gluteal, direct posterior (DP) approach. Incision into the ITB is not required and quadratus femoris is preserved. The conjoined tendon, occasionally the piriformis, and rarely the obturator externus are released. Over the last 5 years I have used intra-operative digital radiography to guide the procedure. A review of published DA results indicates at least clinical equivalence with the DP. Recent publications describing DA technique acknowledge that it is required, in most cases, to release conjoined tendon, and possibly piriformis. Personal communication with DA practitioners suggests even more “posterior release” is required. I will illustrate that the DP is a very close anatomic equivalent of the DA. It is therefore the handling of critical anatomic structures along with the use of image guidance that optimise outcome in THA and not mini-anterior or DA exclusively

Late aseptic loosening of total hip arthroplasty (THA) components due to wear debris especially sub-micron Polyethylene induced osteolysis has been identified to be the major cause for revision. Therefore, the use of wear resistant designs and materials is imperative for the long-term success of articulating implants. One of the most promising articulations for THA regarding extremely low wear is the hard-on-hard Alumina/Alumina combination with a long history in orthopaedics accumulating to now 30 years of experience. Alumina Ceramic: Aluminum-Oxide Ceramic (Alumina, Al2O3, ISO 6474) is an extremely hard material that can only be scratched and also machined and polished by diamond. It has excellent mechanical properties but is brittle as are most ceramic materials and can, therefore, not be used for highly stressed implants like an artificial hip joint stem. Due to its ionic structure it is hydrophilic allowing liquids to bound to and lubricate its surface. Alumina’s hardness allows a polishing to a low roughness, which is entirely inverse and therefore able to create lubricating “pools.”. Density, purity and grain size in combination with an optimised manufacturing process are crucial for the final properties of Alumina and have been sub-optimal at the early pioneering times. Also the design has to be adapted to the critical properties of this ceramic. The biological activity of Alumina is graded as bio-inert and no direct osteointegration is to be expected, also proven by clinical experience. Alpha Alumina is bio-stable and practically insoluble in the body environment. Therefore, ageing or any systemic reaction in the human body with this ceramic is of no concern. First Generation Alumina Ceramic: Boutin has introduced Alumina ceramic components for articulation with itself for THA in 1970, followed by Mittelmeier and other surgeons. First reports of its combination with UHMWPE cups date back to 1972. More than one million Alumina heads have been worldwide implanted since then. Problems regarding fracture of the head were mostly encountered with collared heads of one design and the cup (especially if placed at > 50 deg abduction position). Run-away wear in case of edge contact have been reported with these first generation implants. A comprehensive retrieval study using a systematic analysis of two different designs confirmed that Alumina/ Alumina couples have a low clinical wear rate and identified the main risk factors that can lead to early failure of such devices. The wear rate of those historic Alumina / Alumina articulations is in the range of less than 5 microns per year. This is one to two orders of magnitude less than for any articulation with Polyethylene cups. Reaction to Alumina wear particles, mostly encountered on catastrophic failure of the historic implant designs is sparse and mostly benign. Third Generation Alumina Ceramic: Significant improvements in material properties and quality have been made since its introduction. The third generation of Alumina has been introduced in 1994 and was a further evolution regarding material properties, manufacturing, quality control and design. Refinement of purity, grain size and manufacturing results in improved fracture and also wear resistance, which decreased from low to almost immeasurable values. With the evolution of this new generation ceramic the problems of the past have been successfully addressed. Following improvements are characteristic for a third generation Alumina:. Improved purity and reduced grain size (Figure 1) for better properties. Improved density, HIP for enhanced toughness and bending strength. Less stress raisers due to laser marking instead of mechanical engraving. Optimised head internal geometry. Rounded and polished rim for risk reduction of runaway wear on sub-luxation. Improved safety due to 100% proof test on heads and inserts. These improvements result in a significant increase in mechanical properties. The risk of head fracture has been reduced for this 3rd generation Alumina ceramic heads from 1 per 500 (0.2%) to 1 per 25 000 (0.025%). The wear resistance of the couple Alumina/Alumina has also been enhanced which was measured in simulator tests to be around 1 micron per year. Tribological investigation involved a series of screening, pendulum and anatomical hip simulator tests with actual Alumina/ Alumina components in respect to the effect of clearance and cup angle (45° & 60°) in a series of tests for up to 5 million cycles. Adverse testing conditions for Alumina e.g. dilution of lubricant, dry and water, high load in swing phase, stop-start, etc in ascending aggressiveness (each at 1 million cycles) have also been investigated. No significant difference in wear volume was found comparing clearance or cup angle for all components tested. A new simulator test set up using a microseparation mode during every single cycle was also run for 5 million cycles combining Alumina from one single manufacturer and also mixing Alumina’s from different manufacturers. The wear in all cases was low and lower than for the first generation Alumina’s. A series of implantations with Alumina/Alumina articulation has been performed since November 1996 according to a prospective multicentric FDA IDE protocol comparing the same implant with CoCr metal heads/PE combinations. Short-term results demonstrate no early complications with this third generation Alumina/Alumina articulation if implanted correctly. The benefit of the dramatically reduced wear rate will show only after longer-term follow-up. Conclusion: Alumina/Alumina articulation demonstrates the lowest wear rate of all available material combinations for THA in the laboratory as well as in clinical praxis. The bulk material as well as its particles is bio-inert, therefore, giving no concern for adverse biological reactions. Problems with earlier designs of Alumina/Alumina articulation have been successfully addressed by taking the identified risk parameters into consideration. Components of the third generation Alumina ceramic and design have been extensively tested. All components pass the mechanical tests. Alumina heads and liners of the third generation in the size and under the conditions tested are safe and efficient. Their wear rate even under the influence of adverse condition is minimal. Further clinical trials parallel the application of this superior articulation couple in an innovative and modern design.Alumina/Alumina is, therefore, the material combination of choice for the active patient with high life expectancy

Purpose: Clinical studies still show significant variability in offset and leg length reconstruction after 28mmTHA. Precise restoration of hip biomechanics is important since it reduces wear and improves stability, abductor function and patient satisfaction. There is a tendency to increase offset and leg length to ensure stability of 28mmTHA. This may not be needed with the more stable LDHTHA and hip resurfacing implants, therefore potentially improving the precision of the hip reconstruction. The aim of this study was to verify this assumption.

Method: Leg length and femoral offset were measured on standardized digital radiographs with a computer software in 254 patients (49 HR, 74 LDHTHA, 132 28mmTHA) with unilateral hip involvement and compared to the normal contralateral side.

Results: Femoral offset was increased in 72% of 28mmTHA (mean +3.3mm), 56% of LDHTHA (mean +1.0mm) and 8% of HR (mean −3.2mm) (intergroup differences p< 0.05). The mean LLI was greater after 28mmTHA (+2,29mm) vs. (−0.45mm for LDHTHA and −1.8mm for HR). The percentage of patients with increased leg length > 4mm was greater for 28mmTHA (11%) compared to LDHTHA (2.7%) and HR (2%).

Conclusion: The stability afforded by the larger head of LDHTHA reduces the surgeon’s tendency to increased leg length and femoral offset to avoid instability as during 28mmTHA. In addition, compared to HR, LDHTHA allows more precise restoration of equal leg length and femoral offset in patient with greater pre operative deformities (low femoral offset and LLI > 1cm). LDHTHA may represent the most precise method of hip joint reconstruction.

Introduction. There is great interest in technologies to improve the accuracy and precision in placing implants for total hip arthroplasty (THA). Malik et al. (J Arthroplasty, 2010) showed that an imageless navigation system could be used to produce accurate measures of acetabular cup alignment compared to a CT-based alignment method using an imaging phantom. In this study we sought to compare the precision of an image-based navigation system with post-operative CT scans in a clinical patient cohort who received navigation-assisted THA. Methods. Eighteen patients with 20 hips consented to this IRB-approved analysis of intra- and post-operative THA cup alignment. All patients received THA with image-assisted alignment (MAKO Surgical, Fort Lauderdale). Nominal cup placement, subject to intraoperative surgeon adjustment and approval, was 40° radiographic inclination (RI) and 20° radiographic anteversion (RA) according to the definitions of Murray (JBJS-Br, 1993). Intraoperative cup alignment was measured by collecting five points on the cup rim with an optically tracked stylus. Postoperative cup alignment was measured by registering pre- and post-operative pelvic models generated from CT scans, and determining the postoperative cup orientation relative to the pre-operative pelvis coordinate system (Figure 1). Repeated measures testing of the CT-based measurements on 10 patient scans showed precision and bias of 0.7° and 0° for radiographic inclination, and 0.6° and 0.1° for radiographic anteversion. Results. Mean cup alignment with navigation and CT was within 1° of the nominal target values (Figure 2). There was not a significant difference in the cup inclination measure between intraoperative and CT-based measures, while the intraoperative measure of anteversion showed a 2° bias compared to the CT-based measures. Using a 5° difference between the intraoperative and postoperative measures as the definition for cup placement outliers, 2 cups (10%) were outliers for inclination and 3 cups (15%) were outliers for anteversion (Figure 3). No cup in this series was an outlier for both inclination and anteversion. Discussion. Optical navigation to confirm cup placement appears to result in relatively few alignment outliers, with no outliers for both angles and no single difference greater than 10°. Although differences between intraoperative and CT-based measures were small, it appears acquisition of a larger number of points on the cup rim could further enhance the precision of the navigation-based surgeon feedback. Consistent with previous studies, cup alignment using optical navigation is more precise than cup alignment using traditional manual methods

We evaluated 3 cases of ceramic-on-ceramic THA in that the evidence of the impingement between the metal neck and the ceramic liner was found. Between July 2007 and January 2008, impingement between the metal and the ceramic liner was found in 3 cases of ceramic-on-ceramic THA during re-operation. The re-operation was performed 3–6 years after the primary surgery because of ceramic head fracture, deep infection and cup loosening. All patients frequently sat on the floor in tailor fashion but did not have any sound in the hip after THA. In all cases, V-shaped indented wear scar was found on the postero-superior aspect of the metal neck. Two ceramic liners could be retrieved. Both showed black staining in the postero-superior portion of the rim. The outer edge of the bearing surface of the retrieved acetabular liners was evaluated with SEM. The black stained area of the acetabular liner rim was found to be roughened. A micro-crack propagating into the deep portion of the ceramic liner was observed in one liner. Our observations suggest that impingement between the ceramic liner and the metal neck can cause crack formation leading to ceramic liner failure in vivo

Peri-operative fracture during routine THA represents one of the “not so fresh” feelings that occur for both patients and surgeons. With the increase in uncemented implants and MIS techniques this truly is a problem on the rise. We have recently examined and quantified the risk factors associated with proximal femoral fracture during THA. Risk factors (risk ratios) identified were: uncemented stems (8.9), anterolateral approach (7.4) and female gender (2.2). Fortunately, treatment with cerclage wiring for uncemented stems has facilitated excellent stem stability and acceptable survivorship with many different femoral component designs. Reduced proximal geometry stems that match the endosteal osseous anatomy have reduced fracture rates at our institution. In our series, cemented stems, however, had decreased survivorship in the presence of a proximal femoral fracture. MIS techniques may accelerate rehabilitation but they certainly permit limited visibility of the proximal femoral and acetabular anatomy and may result in less accurate component position. Relatively high fracture rates in series of MIS-THA have been reported. A bigger concern, however, is the unrecognised fracture that displaces postoperatively and requires a return to surgery for treatment with or without revision and mandates that we “see it before it sees us!” Cerclage wiring with looped Luque wires has been our treatment of choice for many years. Wires are significantly less expensive than cables and have proven to be durable in our series. They allow intraoperative repositioning and variable tightening in multiple locations. Cable fretting and breakage has been common in our experience with braided cable devices. Acetabular fracture during uncemented THA is most likely an under-reported occurrence and has been associated with elliptical component designs and under-reaming. In the presence of a stable cup, long-term performance has been acceptable

Over the past 10 years, the orthopedic community has witnessed an increased interest in more conservative surgical techniques for hip arthroplasty. During this time, second-generation hip resurfacing and minimally invasive surgery enjoyed extensive marketing attention. After a decade of this renewed interest, both of these methods have met with serious concerns. As hip resurfacing numbers decline, both patients and surgeons are looking for other potentially successful conservative treatments to THA. This search has focused surgeon interest toward short-stem designs. Today, a variety of short-stem implants are available with very little clarification of design rationale, fixation features, surgical technique, and clinical outcomes. Virtually every major implant company now offers a “short stem,” and now there are a plethora of different designs. It is important to note, however, that not all short stems achieve initial fixation at the same bone interface region. Furthermore, surgical techniques vary greatly, and postoperative radiographic interpretation of short-stem position and fixation need to be carefully scrutinized. The purpose of this paper is to review past, present, and potential future developments of short femoral stems and to present a classification system that can offer guidance when reporting on the many different stem variations. Short Curved neck-sparing stem (JISRF classification 2a). Recently, new designs are following Pipino's Biodynamic stem style of saving the femoral neck. These designs feature a short curved stem that finds its stabilization contact region in the femoral neck and saves considerable bone in the medial calcar region. In addition, the curvature of the stem prevents violation of the lateral trochanteric region. The shorter stem also reduces blood loss by not reaming the femoral canal distally. These style stems generally have a variable stem length between 90 and 135 mm. This might not appear much shorter than conventional cementless stems (110 to 150 mm). However, the shorter curved neck sparing stems penetrate on average 1 to 2 cm less distally in the femoral canal. Short stems have a definite role in modern THA, as greater emphasis is being placed on soft tissue and bone sparing techniques and as refinements continue in the understanding of proximal femoral fixation. Metaphyseal short stems have significantly less surface contact area compared with conventional length stems and as a result, they might have less torsional and axial resistance. Neck-retaining short stems provide additional axial and torsional stability and reduced stress at the implant– bone interface and may be a consideration in the more active patient profile. Bone quality and the patient's physical activity should be considered prior to the selection of short-stem devices. Many short-stem designs have considerably different style features that may alter bone remodeling. Knowing the design and the required technique is vital to fit the device properly to the patient. The variations of short stems available call for caution in their overall use until there is better understanding of how dependent these stems are on individual stem features, bone quality, and surgical techniques. Overall, the authors are cautiously optimistic and continue advocating their selective use

Introduction. Total hip arthroplasty is considered to be one of the most successful orthopaedic interventions. Acetabular component positioning has been shown to affect dislocation rates, component impingement, bearing surface wear rates, and need for revision surgery. The safe zones of acetabular component positioning have previously been described by Lewinnek et al. as 5 to 25 degrees of cup version and 30 to 50 degrees of inclination. Callanan et al. later modified the inclination to 30 to 45 degrees. Our aim was to assess whether THA via robotic assisted posterior approach (PA) improves acetabular component positioning compared to fluoroscopic guided anterior approach THA (AA). Methods. Subjects. This study is a matched-pair case-control study using prospectively collected data from THAs done between January 2012 and December 2013. Patients who underwent primary THA using the PA or AA by the senior surgeons (MH and JAR) were included in the study. Ninety-six patients (of 176; 55%) underwent AA and 80 (of 176; 45%) underwent PA THAs. The matching process was performed by an observer blinded to the radiographic outcomes (EK). Patients were matched for sex and BMI +− 8 units. Seventy-nine patients who had AAs were manually matched to 79 patients who had PAs. Surgical Techniques. For the AA THAs, the patient is supine and the approach is performed through a modified smith Peterson approach. Acetabular cup positioning is assessed intraoperatively with fluoroscopy. For the PA THAs, the patient in the lateral position using the posterior approach. Acetabular cup positioning was guided by the MAKO robotic hip system using preoperative CT scans of the involved hip. Radiographic Measurements. The radiographic measurements were done manually using a standardized technique by two observers blinded to the type of arthroplasty performed. Spearman's rank correlation coefficient was used to test user dependent variability. Means were used for final calculations. Statistical Analysis. The average cup inclination and anteversion angles were calculated. Calculation of the number of hips that were in the safe zones of Lewinnek (inclination, 30°–50°; anteversion, 5°–25°) and Callanan (inclination, 30°–45°; anteversion, 5°–25°) regarding inclination, anteversion, and a combination of both were done for both groups. Independent t-tests were performed to compare both groups for sex, BMI, and inclination and anteversion angles. Fisher's exact test was used to compare both groups regarding the number of hips in the safe zones of Lewinnek and Callanan. Relative risk and absolute risk reduction were calculated. Results. There was no significant difference in BMI between the two groups. Intraobserver agreement was found to be .92 and 0.82 for inclination and anteversion, respectively. Compared to fluoroscopic guided THAs, THAs performed with robot assistance were found to be more often in the safe zone of Lewinnek (90% vs. 75%, p=0.02, RR 0.40 [0.19–0.85] p=0.01). This pattern was observed in the zone of Callanan and approached statistical significance (80% vs. 68%, p=0.11, RR 0.64 [0.37–1.10] p=0.11). Conclusion. Compared to fluoroscopic assisted THA, robot assisted THAs are more likely to be within the safe zone of Callanan and Lewinnek

Introduction: In total hip arthroplasty, the angle of acetabular component is a critical factor for the postoperative dislocation and the longevity of prostheses. The angle is principally determined in relation to anterior pelvic plane. It is reported that the pelvis tends to tilt posteriorly along with aging. Furthermore, the pelvic tilt might change after THA. The changes might be infiuenced by the hip condition and lumbar lordosis. We measured the pelvic tilt and the lumbar lordosis, and evaluated the effects of contralateral hip and lumbar lordosis on pelvic tilt after THA. Materials and Methods: Fifty-one unilateral patients and 30 bilateral patients were enrolled in this study. The diagnosis was dysplastic osteoarthritis in all patients. In unilateral patients, the hip was affected in one side and the other hip was normal or acetabular dysplasia without symptoms. In bilateral patients, THAs in both hips were done within two months. Pelvic inclination angle (PIA) and lumbar lordotic angle (LLA) were measured on the standing lateral X-rays before operation and 1-month, 6-month and 1-year post-operation. The effects of patient age, BMI, ROM of the hip, preoperative PIA and LLA on the changes of PIA were statistically investigated using multiple linear regression analysis. We divided the patients into three groups with regard to pre-operative PIA (anterior group: PIA < 0, intermediate group: 0 < PIA < 10, posterior group: PIA > 10) and with regard to pre-operative LLA (insufficient group: LLA < 20, moderate group: 20 < LLA < 40, severe group: LLA > 40). Results: Overall, significant factor was only preoperative PIA. In bilateral cases, preoperative PIA and patient age affected the changes of PIA after THA. In patients with severe lordosis, preoperative PIA and LLA were significant factors. PIA increased in anterior tilt group and PIA did not change in intermediate group, while PIA gradually decreased in posterior group. In insufficient lordosis group, PIA remarkably increased after THA compared with that in severe group. Discussion: Pelvic tilt after THA has been reported without considering the conditions of contralateral hip and lumbar spine. By categorizing patients with regard to the conditions of hips and lumbar spine, we can prospect the tendency of the direction of PIA changes. These results indicated that pre-operative PIA was related the changes of PIA in bilateral group. PIA slightly increased in all bilateral patients, PIA tended to close each other in unilateral patients. Further investigation is necessary to prospect the estimated PIA value after THA

Introduction. In THA, fretting corrosion at the head-stem taper junction has emerged as a clinical concern that may result in adverse local tissue reactions, even in patients with a metal-on-polyethylene bearing [1]. Taper junctions that employ a ceramic head have demonstrated reduced corrosion at the interface [2]. However, during revision surgery with a well-fixed stem, a titanium sleeve is used in conjunction with a ceramic head to ensure proper fit of the head onto the stem and better stress distribution. In vitro testing has suggested that corrosion is not a concern in sleeved ceramic heads [3]; however, little is known about the in vivo fretting corrosion of the sleeves. The purpose of this study was to investigate fretting corrosion in sleeved ceramic heads. Materials and Methods. Between 2001 and 2014, 35 sleeved ceramic heads were collected during revision surgery as part of a multi-center retrieval program. The sleeves were all fabricated from titanium alloy and manufactured by 4 companies (CeramTec (n=14), Smith & Nephew (Richards, n=11), Stryker (n=5), and Zimmer (n=5)). The femoral heads were made from 3 ceramics (Alumina (n=7), Zirconia (n=11), and Zirconia-toughened Alumina (n=17)). Sleeve dimensions (length and thickness) were measured using calibrated calipers. Fretting corrosion of the sleeves and available associated stems was scored using a 4-point, semi-quantitative scoring system [4], with 1 being little-to-no damage, and 4 corresponded to severe fretting corrosion. Five sleeves could not be extracted; thus the external surface was not scored. Results. Moderate-to-severe fretting corrosion scores (Score ≥ 2) were observed in 97% (34/35) of internal tapers (sleeve-femoral stem contact), 57% (17/30) of external tapers (sleeve-femoral head contact), and 65% (11/17) of the stems. The internal sleeve had higher fretting corrosion scores than the external taper (Mean Score Difference [MSD] = 1.1; p = 0.001) and stem (MSD = 0.7; p = 0.016). Fretting corrosion scores were correlated with implantation time at all surfaces (Rho ≥ 0.53; p ≤ 0.015). Scores were not correlated with sleeve dimensions (p > 0.05). Fretting corrosion scores of the external sleeve correlated directly with activity level (p = 0.005) and inversely with patient age (p = 0.03). Discussion. The retrieval data shows that fretting corrosion can occur in these components, particularly on the internal surface of the sleeve. The corrosion scores were similar to levels observed in prior studies of tapers in CoCr heads [2]. Implantation time was the main predictor of increased fretting corrosion. The impact of ceramic material and sleeve design currently remain unclear as the analyses were confounded with implantation time. Thus, more detailed and quantitative analyses are required to fully determine the factors that influence fretting corrosion of sleeved ceramic heads in THA

BACKGROUND. Many patients who underwent a THA, report a feeling of more “physiological” hip and of faster recovery when bigger heads are used. The aim of this study is to evaluate the walking recovery of patients after THA with different head diameters by the means of gait analysis. MATERIALS AND METHODS. A prospective, randomized, blind study was conducted on 60 patients operated by THA at our Institution. Inclusion criteria were: primary hip arthritis, women, age between 55 and 70 years. Exclusion criteria were: other problems influencing walking ability (previous operations of the lower limbs, spine disorders, knee or controlateral hip arthritis). The same uncemented stem, same uncemented press-fit cup, same surgical technique and approach (posterolateral), same surgeons, same postoperative protocol and rehabilitation were employed. The only difference was the head diameter. The patients were randomized into three groups, of twenty patients each one (28mm Cer-on-XPE, 36mm Cer-on-XPE, >42mm Met-on-Met). The gait evaluation have been performed at three temporal steps: preoperatively, two months postoperatively and four months postoperatively. Kinematic parameters were acquired with Elite opto-electronic system (BTS, Milan, Italy) equipped with 6 cameras at 100 Hz frame rate. The system is integrated with a force platform (Kistler, CH) and a synchronic video system using two cameras (BTS, Milan, Italy). Data acquisition and processing were carried out using passive markers positioned according to Davis protocol. At least ten trials for each session were collected in order to assess the repeatability of the results. Gait analysis included kinematic parameters (temporal-spatial parameters and joint angular values) and kinetic parameters (ground interaction forces during walking). Articular moments and powers were computed on the basis of data obtained from dynamometric platform along with those given by kinematic analysis. All patients were compared to a control group. Wilcoxon signed rank test was employed for statistical evaluation. RESULTS. At a preliminary evaluation (still in progress) and statistical analysis, temporal-spatial parameters show no significant differences among the three groups. All the variables of step length, stride length, cadence and velocity show statistical significant improvements towards the standard values, in the four months follow-up in all the groups, and the improvement does not depend on the side operated. CONCLUSIONS. The preliminary evaluation of this study shows that there is no statistical significant difference in standard gait analysis parameters in patients with different head diameters (28mm, 36mm, >42mm) after THA

INTRODUCTION. Patients less than 60 years old have been reported to have a higher risk of revision following total hip arthroplasty (THA) than older patient cohorts, possibly to due higher activity, a higher incidence of deformity and greater probability of prior surgery. Ceramic-on-ceramic bearing surfaces have been proposed for use in young and active individuals due to their low wear, low risk of adverse biologic reaction, and long-term survivorship. We assessed the clinical results and long-term survivorship of uncemented ceramic-on-ceramic THA in a young patient population. METHODS. For the six year period from May 1999 to March 2005, 278 hip replacements in 244 patients less than 60 yeas of age at the time of surgery were performed using alumina ceramic-ceramic bearings. All hips had uncemented titanium femoral and acetabular components. The ceramic liner was fixed to the shell with an 18-degree flush-mounted taper design. Patients were followed clinically and radiographically. Attempts were made to contact all patients who had not been seen in the prior 3 years. Of the 278 hips, 17 hips (16 patients) remain lost to follow-up, leaving 261 hips (228 patients; 155 hips in men, 106 hips in women) for assessment. Mean age of the patients was 46.2 years at the time of surgery (range 17.8 to 59.9 years). 17% of hips had at least one previous hip surgery. Mean time following surgery was 9.75 years (range 2 to 16.8 years). RESULTS. At mean 9.75 year follow-up, none of these 261 hips experienced early or late deep infection or dislocation. Four patients died of causes unrelated to their arthroplasty at a mean of 6.1 years, all with well functioning constructs. Nine hips (3%) were revised: 2 stems and 2 cups failed to osseointegrate; 1 modular neck component sustained a modular neck fracture; and ceramic fracture occurred in 1 femoral head and 3 liners. Three of the 4 patients with fracture sustained severe trauma from life-threatening injuries. CONCLUSION. Total hip arthroplasty in young patients demonstrates excellent survivorship when uncemented titanium implants are coupled with ceramic-ceramic bearings