Postoperative Pelvic Radiographs Research Articles

Does the utilization of fluoroscopy affect the accuracy of prosthesis position in patients undergoing hip replacement surgery via the direct anterior approach compared to the posterolateral approach for an experienced surgeon? A single-center retrospective study

BackgroundThe direct anterior approach (DAA) for total hip arthroplasty (THA) has gained popularity due to perceived advantages in achieving better early outcomes. However, the theoretical benefits such as precise implant positioning and accurate leg length restoration are still inconsistent. In this study, we compared implant position and leg length discrepancy (LLD) of the DAA and posterolateral approach (PLA) conducted by a single surgeon who had mastered both approaches.MethodsThis study retrospectively reviewed the medical records and radiographic images of 244 patients who underwent THA between 2012 and 2021 by a single experienced surgeon using either the DAA (n = 120) or PLA (n = 124). Postoperative pelvic anteroposterior radiographs at 6 months follow-up were used to assess acetabular component inclination and anteversion, as well as LLD. Mann-Whitney U tests and Chi-squared test were performed to compare outcomes between the two approaches.ResultsNo significant differences were observed in patient demographics between the two groups. The DAA group demonstrated significantly lower postoperative LLD (0.00 mm) compared to the PLA group (5.00 mm, p < 0.0001). No significant difference was observed in the Lewinnek zone for cup anteversion and inclination angles between the two groups.ConclusionsFor experienced surgeons in other approaches, our findings suggest transferring to the DAA may not substantially improve cup positioning, but it might slightly enhance limb length measurement. For surgeons already proficient in other approaches and deciding to maintain those approaches, their primary concern for optimal THA outcome should be striving for leg length equivalence.

The accuracy of cup anteversion measurement on postoperative pelvic radiographs: A comparative retrospective cohort study between DDH and non-DDH patients

Rationale and objectivesPostoperative pelvic radiographs remain a vital tool for assessing cup orientation after total hip arthroplasty (THA), with the accuracy influenced by various factors. The objective of this study is to investigate the accuracy of cup anteversion measurement in developmental dysplasia of the hip (DDH) patients and others based on postoperative pelvic radiographs conducted under the current heavy workload conditions. Materials and methodsPatients who underwent THA at our hospital with both postoperative X-ray and CT images from January 2020 to December 2022 were included in this retrospective cohort study. Virtual X-ray films were generated using digitally reconstructed radiographs (DRR) technology from CT images, with pelvic position perfectly controlled. Radiographic anteversion (RA) was measured on 3D-CT, virtual X-rays, and actual postoperative X-rays, abbreviated as RA_3D, RA_DRR, and RA_Xray, respectively. A repeated-measures analysis of covariance (ANCOVA) was utilized to evaluate the variations in RA within and between different groups across three methods. The Bland-Altman plot analysis showed the variations among methods in DDH and non-DDH patients, setting a clinically acceptable limits of agreement (LOA) at ±5°. ResultsThis study included 154 hip cases, with 63 DDH and 91 other diseases. Repeated-measures ANCOVA revealed a descending trend in RA across three methods, with differences of 2.64° (DDH) vs. 2.74° (others) from 3D to DRR, and 4.89° (DDH) vs. 1.07° (others) from DRR to X-ray. The group by methods interaction effect were significant (p = 0.002). Significant statistical differences in RA_Xray (P = 0.035) were observed between DDH and non-DDH patients, but not in RA_3D and RA_DRR. Bland-Altman plots showed 71.4 % of DDH patients exceeded the clinically acceptable LOA, compared to 36.3 % of other patients. ConclusionOur study indicated that under the current intense workload, the reliability of assessing cup anteversion using postoperative pelvic radiographs is challenged, especially in patients with DDH.

Comparison of Surgical Results of Modified Stoppa and Ilioinguinal Approach in Patients with Acetabular Fractures Involving Quadrilateral Surface Fractures.

The aim of this study was to evaluate the results of surgical treatment in patients with acetabular fractures with a fractured quadrilateral surface treated using two different approaches. The study included 106 patients who were operated on with ilioinguinal (group A) or modified Stoppa (group B) technique for acetabular fracture with a fractured quadrilateral surface between 2011 and 2020 in our clinic. The quality of reduction was evaluated according to Matta criteria and postoperative pelvic (anteroposterior, external oblique, iliac oblique) radiographs. Evaluation of hip function was recorded using the Merle d'aubigne and Postel Score and Harris Hip Score. Among the patients included in the study, there were 45 patients in group A and 61 patients in group B. When the group data were compared, it was seen that the modified Stoppa approach was superior in terms of intraoperative reduction quality, radiological data, Harris hip score, Merle d'aubigne and PostelScore. (Respectively p=0.40, p=0.49, p=0.040, p=0.028). : Modified Stoppa approach has successful clinical and radiological outcomes and better reduction quality and hip scores than ilioinguinal approaches in acetabular fractures involving quadrilateral plates.

Treatment of pelvic giant cell tumor by wide resection with patient-specific bone-cutting guide and reconstruction with 3D-printed personalized implant

BackgroundThis study reports our experience in the treatment of aggressive pelvic GCT through wide resection assisted with patient-specific bone-cutting guides (PSBCGs) and subsequent reconstruction with 3D-printed personalized implants (3DPIs), aiming to present the operative technique of this method and evaluate its clinical efficacy.MethodsWe retrospectively analyzed seven patients who underwent wide resection of pelvic GCT followed by reconstruction with 3DPIs from August 2019 to February 2021. There were two males and five females, with a mean age of 43 years. PSBCGs and 3DPIs were prepared using 3D-printing technology. The operational outcomes, local recurrence, radiological results, and any associated complications of this technique were assessed. And the functional outcomes were assessed according to the Musculoskeletal Tumor Society (MSTS) 93 functional score.ResultsThe mean follow-up time was 35.3 months (range 28–45 months). There was no intraoperative complication. Negative surgical margins were achieved in all patients. Postoperative pelvic radiographs showed that 3DPIs matched the shape and size of the bone defect. The anterior–posterior, inlet, and outlet pelvic radiograph demonstrated precise reconstruction consistent with the surgical planning. In addition, tomosynthesis‐Shimadzu metal artifact reduction technology (T-SMART) showed good osseointegration at an average of three months after surgery (range 2–4 months). There was no local recurrence or tumor metastasis. The average MSTS score was 24.4 (range 23–27) at the last follow-up. Delayed wound healing was observed in one patient, and the wounds healed after debridement. Prosthesis-related complications were not detected during the follow-up, such as aseptic loosening or structure failure.ConclusionsThe treatment of aggressive pelvic GCTs through wide resection assisted with PSBCGs and subsequent reconstruction with 3DPIs is a feasible method, which provides good clinical results and reasonable functional outcomes.

Acetabular orientation in triple pelvic osteotomy: is intraoperative fluoroscopy reliable?

PurposeIn pelvic osteotomies, unfavorable balancing of the anterior and posterior acetabular wall can affect the longevity of the natural joint. This raises the question, whether intraoperative fluoroscopy is sufficiently accurate. The objective was to assess the correlation between acetabular parameters [lateral center edge angle (LCEA), acetabular index (AI), anterior wall index (AWI), posterior wall index (PWI)] acquired on intraoperative fluoroscopic images and postoperative pelvic radiographs and to analyze intra- and interobserver reliability of these parameters.MethodsA retrospective examination was conducted on 206 consecutive cases (176 patients) after triple pelvic osteotomy (TPO). Every patient received a pre- and postoperative pelvic radiograph in supine position in exactly the same technique. A highly standardized surgical sequence allowed consistent intraoperative fluoroscopic imaging. LCAE, AI, PWI and AWI were measured by an experienced orthopedic surgeon and an orthopedic surgeon in training. Statistics comprised a priori power analysis, Bland–Altman analysis and intraclass correlation coefficient (ICC).ResultsA total of 165 cases were included. ICC between the parameters of the fluoroscopic images and postoperative radiographs was for LCEA: 0.935, AI: 0.936, AWI: 0.725 and PWI: 0.878. Intraobserver ICC for all parameters ranged from 0.953 to 0.989, interobserver ICC from 0.798 to 0.968, respectively.ConclusionIn the surgical treatment of hip dysplasia by means of TPO, intraoperative fluoroscopic imaging has proven to be reliable and accurate. Intraobserver correlation was excellent for all parameters. The correlation between the intraoperative fluoroscopic images and postoperative radiographs ranged from good to excellent, with the lowest values for the acetabular wall indices (AWI and PWI).

Deep Learning Improves Osteonecrosis Prediction of Femoral Head After Internal Fixation Using Hybrid Patient and Radiograph Variables.

Femoral neck fractures (FNFs) are a great public health problem that leads to a high incidence of death and dysfunction. Osteonecrosis of the femoral head (ONFH) after internal fixation of FNF is a frequently reported complication and a major cause for reoperation. Early intervention can prevent osteonecrosis aggravation at the preliminary stage. However, at present, failure to diagnose asymptomatic ONFH after FNF fixation hinders effective intervention at early stages. The primary objective of this study was to develop a predictive model for postoperative ONFH using deep learning (DL) methods developed using plain X-ray radiographs and hybrid patient variables. A two-center retrospective study of patients who underwent closed reduction and cannulated screw fixation was performed. We trained a convolutional neural network (CNN) model using postoperative pelvic radiographs and the output regressive radiograph variables. A less experienced orthopedic doctor, and an experienced orthopedic doctor also evaluated and diagnosed the patients using postoperative pelvic radiographs. Hybrid nomograms were developed based on patient and radiograph variables to determine predictive performance. A total of 238 patients, including 95 ONFH patients and 143 non-ONFH patients, were included. A CNN model was trained using postoperative radiographs and output radiograph variables. The accuracy of the validation set was 0.873 for the CNN model, and the algorithm achieved an area under the curve (AUC) value of 0.912 for the prediction. The diagnostic and predictive ability of the algorithm was superior to that of the two doctors, based on the postoperative X-rays. The addition of DL-based radiograph variables to the clinical nomogram improved predictive performance, resulting in an AUC of 0.948 (95% CI, 0.920–0.976) and better calibration. The decision curve analysis showed that adding the DL increased the clinical usefulness of the nomogram compared with a clinical approach alone. In conclusion, we constructed a DL facilitated nomogram that incorporated a hybrid of radiograph and patient variables, which can be used to improve the prediction of preoperative osteonecrosis of the femoral head after internal fixation.

What Are the Interobserver and Intraobserver Variability of Gap and Stepoff Measurements in Acetabular Fractures?

Gap and stepoff values in the treatment of acetabular fractures are correlated with clinical outcomes. However, the interobserver and intraobserver variability of gap and stepoff measurements for all imaging modalities in the preoperative, intraoperative, and postoperative phase of treatment is unknown. Recently, a standardized CT-based measurement method was introduced, which provided the opportunity to assess the level of variability. (1) In patients with acetabular fractures, what is the interobserver variability in the measurement of the fracture gaps and articular stepoffs determined by each observer to be the maximum one in the weightbearing dome, as measured on pre- and postoperative pelvic radiographs, intraoperative fluoroscopy, and pre- and postoperative CT scans? (2) What is the intraobserver variability in these measurements? Sixty patients with a complete subset of pre-, intra- and postoperative high-quality images (CT slices of < 2 mm), representing a variety of fracture types with small and large gaps and/or stepoffs, were included. A total of 196 patients with nonoperative treatment (n = 117), inadequate available imaging (n = 60), skeletal immaturity (n = 16), bilateral fractures (n = 2) or a primary THA (n = 1) were excluded. The maximum gap and stepoff values in the weightbearing dome were digitally measured on pelvic radiographs and CT images by five independent observers. Observers were free to decide which gap and/or stepoff they considered the maximum and then measure these before and after surgery. The observers were two trauma surgeons with more than 5 years of experience in pelvic surgery, two trauma surgeons with less than 5 years of experience in pelvic surgery, and one surgical resident. Additionally, the final intraoperative fluoroscopy images were assessed for the presence of a gap or stepoff in the weightbearing dome. All observers used the same standardized measurement technique and each observer measured the first five patients together with the responsible researcher. For 10 randomly selected patients, all measurements were repeated by all observers, at least 2 weeks after the initial measurements. The intraclass correlation coefficient (ICC) for pelvic radiographs and CT images and the kappa value for intraoperative fluoroscopy measurements were calculated to determine the inter- and intraobserver variability. Interobserver variability was defined as the difference in the measurements between observers. Intraobserver variability was defined as the difference in repeated measurements by the same observer. Preoperatively, the interobserver ICC was 0.4 (gap and stepoff) on radiographs and 0.4 (gap) and 0.3 (stepoff) on CT images. The observers agreed on the indication for surgery in 40% (gap) and 30% (stepoff) on pelvic radiographs. For CT scans the observers agreed in 95% (gap) and 70% (stepoff) of images. Postoperatively, the interobserver ICC was 0.4 (gap) and 0.2 (stepoff) on radiographs. The observers agreed on whether the reduction was acceptable or not in 60% (gap) and 40% (stepoff). On CT images the ICC was 0.3 (gap) and 0.4 (stepoff). The observers agreed on whether the reduction was acceptable in 35% (gap) and 38% (stepoff). The preoperative intraobserver ICC was 0.6 (gap and stepoff) on pelvic radiographs and 0.4 (gap) and 0.6 (stepoff) for CT scans. Postoperatively, the intraobserver ICC was 0.7 (gap) and 0.1 (stepoff) on pelvic radiographs. On CT the intraobserver ICC was 0.5 (gap) and 0.3 (stepoff). There was no agreement between the observers on the presence of a gap or stepoff on intraoperative fluoroscopy images (kappa -0.1 to 0.2). We found an insufficient interobserver and intraobserver agreement on measuring gaps and stepoffs for supporting clinical decisions in acetabular fracture surgery. If observers cannot agree on the size of the gap and stepoff, it will be challenging to decide when to perform surgery and study the results of acetabular fracture surgery. Level III, diagnostic study.

How to restore rotation center in total hip arthroplasty for developmental dysplasia of the hip by recognizing the pathomorphology of acetabulum and Harris fossa?

PurposeTo restore rotation center exactly in total hip arthroplasty (THA) is technically challenging for patients with end-stage osteoarthritis due to developmental dysplasia of the hip (DDH). The technical difficulty is attributable to the complex acetabular changes. In this study, we investigated the pathomorphology of acetabulum and Harris fossa of Crowe types I to IV and discussed the method of restoring rotation center of the hip.MethodsThis study retrospectively reviewed 56 patients (59 hips) who underwent cementless THA due to end-stage osteoarthritis of DDH. The pathomorphology of acetabulum and Harris fossa was observed during operations. Using the preoperative and postoperative pelvic radiographs, the vertical and the horizontal distances of hip rotation center were measured in order to evaluate the effects of restoring rotation center of the hip.ResultsAdult DDH acetabulum could be classified into four basic pathological types which include the shallow cup shape, the dish shape, the shell shape, and the triangular shape. Adult DDH Harris fossa could be classified into four pathological types, including the crack shape, the closed shape, the triangle shape, and the shallow shape, in accordance with the osteophyte coverage. The vertical and horizontal distances of hip rotation center on the pelvic radiographs before and after operations were as follows: the preoperative vertical distance of hip rotation center was (39.96 ± 5.65) mm, and the postoperative one was (13.83 ± 2.66) mm; the preoperative horizontal distance of hip rotation center was (42.15 ± 6.42) mm, and the postoperative one was (28.12 ± 4.56) mm.ConclusionsThe acetabulum and Harris fossa can display different pathological types on account of different degrees of dislocation and osteophyte hyperplasia in the end-stage osteoarthritis of adult DDH. The hip rotation center can be accurately restored by locating the acetabular center with Harris fossa and acetabular notch as the marks.

The \u2018critical trochanter angle\u2019: a predictor for stem alignment in total hip arthroplasty

IntroductionStem malalignment can affect offset reconstruction and may result in gluteal muscle insufficiency. In this retrospective study, a novel geometric angle named ‘critical trochanter angle’ (CTA) is described and investigated towards the risk of malposition of a collarless straight tapered hydroxyapatite-coated stem in primary total hip arthroplasty (THA).Material and methodsA total of 100 cementless THA were implanted in patients with unilateral coxarthrosis via the direct anterior (n = 50) or direct lateral Hardinge approach (n = 50) in a two surgeon setting using the Corail® or Trendhip® stem (DePuy Synthes or Aesculap). Stem alignment was analysed in postoperative AP pelvic radiographs and correlated to the CTA: the angle crest was defined by the intersection of the femoral shaft and neck axis and the angle was measured between the shaft axis and a leg intersecting the vertex between the lateral and superoposterior facet of the trochanter.ResultsForty-seven stems were implanted in varus (≥ + 1°), 42 in neutral (< + 1°/> − 1°) and 11 in valgus position (≤ − 1°). The mean critical trochanter angle was 25.0° (SD ± 7.5°), and there was a negative and statistically significant correlation to stem alignment (r = − 0.52; p ≤ 0.001) independent from the surgical approach. For stem malposition of 2° and above (n = 23), mean CTA was 17.2° for varus (n = 20) and 31.6° for valgus (n = 3). A CTA lesser or equal to 22.75° had a sensitivity of 90% and specificity of 80% for varus stem position of 2° or greater. Specificity raised to 100% with a cutoff CTA of 12.5° or lesser.ConclusionVarus stem alignment in THA is associated with coxa vara deformity and a radiological low CTA. In preoperative planning, the critical trochanter angle can help to evaluate the risk for intraoperative stem malpositioning. If navigation or robotic assistance is not available when using this stem design, we recommend an intraoperative x-ray to verify correct implant positioning in patients with a CTA under 20° or above 30°.

Restoring femoral offset and leg length; the potential of a short curved stem in total hip arthroplasty

BackgroundTotal hip arthroplasty (THA) is a very successful procedure in orthopedics. Still polyethylene wear and gait deficits are limiting the clinical success.It is important to reconstruct leg length (LL) and femoral offset (FO) anatomically in order to have the best possible result of a THA. Gait deficits can arise due to leg length discrepancy as well as changes in the abductor moment arm. In THA, LL and FO are strongly determined by the orientation, size and geometry of the femoral stem. MethodsThis radio-anatomical study used the data of a prospective cases series of 112 patients who underwent 126 primary THAs and had completed a 1-year follow-up examination. FO and LL were compared between the conventional straight stem in vivo and a computed simulated implantation of a short curved stem, using the pre- and postoperative pelvic radiographs of the same patients. ResultsIn this simulation of the short curved stem statistically significantly restored native FO (p = 0.010) and LL (p = 0.000) better, compared to the conventional straight stem. ConclusionsThus, the short curved stem restores FO and LL better, and could potentially prevent gait deficits.

Modular Versus Monoblock Hemiarthroplasty in Trauma: A 5-Year Retrospective Analysis of Radiographic and Clinical Outcomes

Introduction: Displaced intraarticular neck of femur fractures for low-demand patients are primarily managed with hemiarthroplasty. The optimal implant design for modularity is unclear. Globally and within Australia, the use of monoblock implants varies significantly by location; however, monoblock use is decreasing in Australia in favour of modular systems, with little evidence-based explanation. This study aimed to compare the radiological and clinical outcomes of monoblock and modular hemiarthroplasties. Methods: This retrospective cohort study involved patients who underwent hemiarthroplasty for neck-of-femur fractures between 2009 and 2013 at the Gold Coast University Hospital. Leg length and femoral offset were measured from post-operative pelvic radiographs. Revision and mortality rates were extracted from hospital medical records and Australian Joint Registry data. Results: A total of 249 patients were evaluated (112 with modular and 147 with monoblock implants). Patient demographics were comparable between the treatment groups; however, the monoblock group comprised significantly older persons. No between-group differences in leg length discrepancies were identified. Femoral offset was under-restored on average by 5.86mm (p&lt;0.05) compared to the uninjured side within the monoblock group. Mortality rates were significantly higher in the monoblock group (23% vs 12%, P=0.026) at the 1-year mark. No significant between-group differences were found in 30-day mortality, length of stay, or revision rates. Discussion: Modular hemiarthroplasty was superior for restoring offset in our cohort, but no group differences were noted for leg length. While modular implants seemed better for restoring normal hip anatomy and were associated with a lower 1-year mortality rate, no other advantages were found.

High incidence of intraoperative calcar fractures with the cementless CLS Spotorno stem.

This study reports on the incidence of intraoperative calcar fractures with the cementless Spotorno (CLS) stem, and the potential role of a learning curve and implant positioning is investigated. After introduction of the CLS stem, 800 consecutive cementless total hip arthroplasties (THA) were analyzed. The incidence of calcar fracture in the first 400 THA was compared with the second 400 THA, in order to study a potential learning curve effect. According to the instruction for users, varus positioning of the stem was avoided and a femoral neck osteotomy was aimed relatively close to the lesser trochanter since these are assumed to be correlated with calcar fractures. Implant positioning (neck-shaft angle, femoral offset and osteotomy-lesser trochanter distance) was measured on postoperative pelvic radiographs of all THA with calcar fractures and 100 randomly selected uncomplicated control cases. Seventeen (2.1%) intraoperative calcar fractures were recorded. The incidence of calcar fracture differed between the first 400 THA (n = 11) and the second 400 THA (n = 6). This difference was not statistically significant (p = 0.220); however, these numbers indicate a trend toward a learning effect. No significant difference in stem positioning nor the height of the femoral neck osteotomy was measured between THA with a calcar fracture (n = 17) and the control cases (n = 100). We report on a high incidence of intraoperative calcar fractures with the use of a CLS stem. The risk for calcar fractures remains clinically significant even after adequate implant positioning in the hands of experienced hip surgeons. Surgeons should be aware of this implant related phenomenon and be alert on this phenomenon intraoperatively.

Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study.

Purpose Accurate assessment of cup orientation on postoperative pelvic radiographs is essential for evaluating outcome after THA. Here, we present a novel method for correcting measurement inaccuracies due to pelvic tilt and rotation. Method In an experimental setting, a cup was implanted into a dummy pelvis, and its final position was verified via CT. To show the effect of pelvic tilt and rotation on cup position, the dummy was fixed to a rack to achieve a tilt between + 15° anterior and -15° posterior and 0° to 20° rotation to the contralateral side. According to Murray's definitions of anteversion and inclination, we created a novel corrective procedure to measure cup position in the pelvic reference frame (anterior pelvic plane) to compensate measurement errors due to pelvic tilt and rotation. Results The cup anteversion measured on CT was 23.3°; on AP pelvic radiographs, however, variations in pelvic tilt (± 15°) resulted in anteversion angles between 11.0° and 36.2° (mean error 8.3°± 3.9°). The cup inclination was 34.1° on CT and ranged between 31.0° and 38.7° (m. e. 2.3°± 1.5°) on radiographs. Pelvic rotation between 0° and 20° showed high variation in radiographic anteversion (21.2°-31.2°, m. e. 6.0°± 3.1°) and inclination (34.1°-27.2°, m. e. 3.4°± 2.5°). Our novel correction algorithm for pelvic tilt reduced the mean error in anteversion measurements to 0.6°± 0.2° and in inclination measurements to 0.7° (SD± 0.2). Similarly, the mean error due to pelvic rotation was reduced to 0.4°± 0.4° for anteversion and to 1.3°± 0.8 for inclination. Conclusion Pelvic tilt and pelvic rotation may lead to misinterpretation of cup position on anteroposterior pelvic radiographs. Mathematical correction concepts have the potential to significantly reduce these errors, and could be implemented in future radiological software tools. Key Points · Pelvic tilt and rotation influence cup orientation after THA. · Cup anteversion and inclination should be referenced to the pelvis. · Radiological measurement errors of cup position may be reduced by mathematical concepts. Citation Format · Schwarz TJ, Weber M, Dornia C et al. Correction of Pelvic Tilt and Pelvic Rotation in Cup Measurement after THA - An Experimental Study. Fortschr Röntgenstr 2017; 189: 864 - 873.

Does fluoroscopy improve acetabular component placement in total hip arthroplasty?

The success of THA largely depends on correct placement of the individual components. Traditionally, these have been placed freehand using anatomic landmarks, but studies have shown poor accuracy with this method. Specifically, we asked (1) does using fluoroscopy lead to more accurate and greater likelihood of cup placement with the Lewinnek safe zone than does freehand cup placement; (2) is there a learning curve associated with the use of fluoroscopy for cup placement; (3) does the use of fluoroscopy increase operative time; and (4) is there a difference in leg length discrepancy between freehand and fluoroscopic techniques? This series consisted of 109 consecutive patients undergoing primary THA, conversion of a previous hip surgery to THA, and revision THA during a 24-month period. No patients were excluded from analysis during this time. The first 52 patients had cups placed freehand, and then the next 57 patients had acetabular components placed using fluoroscopy; the analysis began with the first patient treated using fluoroscopy, to include our initial experience with the technique. The abduction, version, and limb length discrepancy were measured on 6-week postoperative pelvic radiographs obtained with the patient in the supine position. Operative time, sex, age, BMI, diagnosis, operative side, and femoral head size were recorded as possible confounders. Cups inserted freehand were placed in the ideal range of abduction (30°-45°) and anteversion (5°-25°) 44% of the time. With fluoroscopy, placement in the Lewinnek safe zone for both measures significantly increased to 65%. The odds of placing the cup in the Lewinnek safe zone for abduction and version were 2.3 times greater with the use of fluoroscopy (95% CI, 1.2-5.0; p=0.03). Patients undergoing primary THAs (32 freehand, 35 C-arm) had cup placement in the safe zone for abduction and version 44% of the time freehand and 57% of the time with fluoroscopy, which failed to reach statistical significance. There was no difference in operative time, patient age, sex, operative side, diagnosis, limb length discrepancy, or femoral head size between the two groups. The use of fluoroscopy to directly observe pelvic position and acetabular component placement increased the success of placement in the Lewinnek safe zone in this cohort of patients having complex and primary THAs. This is a simple, low-cost, and quick method for increasing successful acetabular component alignment. The study population included a large proportion of patients having complex THAs, and further validation of this technique in patients undergoing straightforward, primary THAs needs to be done to understand if similar gains in accuracy for component placement can be expected in that group. Level III, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

Radiographic and clinical analysis of pelvic triple osteotomy for adult hip dysplasia

BackgroundAdult Hip Dysplasia (AHD) has been strongly linked with the development of hip osteoarthritis. The complexity and therefore resultant steep learning curve of the Bernese osteotomy for AHD has been well described. The purpose of this study was to analyse the efficacy of a technically less demanding interlocking pelvic triple osteotomy.MethodsPre and postoperative pelvic radiographs of 8 hips in 7 patients who underwent pelvic osteotomy between January 2010 and December 2011 were corrected to a standardised orientation using a validated software package, Hip2NormTM, and this tool was then used to measure hip parameters used for assessing dysplasia. The Lateral Centre Edge Angle (LCEA), the Acetabular Index of the Weight-Bearing Zone (AIWB), and the percentage Acetabular Coverage of the Femoral Head (ACFH) were all calculated and compared. Oxford hip scores, WOMAC hip scores, and UCLA activity scores were clinical outcome measures.ResultsAverage LCEA correction was 23.8 deg, from a mean of 8.8 deg preoperatively to 32.6 deg postoperatively. AIWB was corrected an average of 21.3 deg (mean 22.5 to 1.2 deg postoperatively) and ACFH was increased on average 23.8% (mean 59.0 to 82.8% postoperatively). At a minimum follow-up of 3 months Oxford hip scores improved from an average of 19.6 preoperatively to 39.4, and the mean UCLA activity index was increased from 3.3 to 7.1 postoperatively. There were two technical complications in the studied procedures, which have resulted in no long-term sequelae.ConclusionsThis study demonstrates the safe and effective use of an interlocking pelvic triple osteotomy to provide correction of radiological parameters and symptomatic improvement of AHD.

Radiographic Analysis of Movements of the Acetabulum and the Femoral Head After Salter Innominate Osteotomy

Salter innominate osteotomy (SIO) is widely used to improve the coverage of the femoral head in dysplastic acetabulum, but the geometric change after osteotomy and its effect on the outcome have not been well elucidated. Pelvic radiographs of the 90 hips in 86 patients who underwent SIO for the treatment of acetabular dysplasia were reviewed and the movement of the distal fragment and the shift of the femoral head after SIO were analyzed. On the basis of the anteroposterior radiographs of the pelvis in a supine position taken at 5 weeks after operation, various parameters including an open-wedged angle at the osteotomy site (lateral rotation angle, LRA), lateral displacement of the distal fragment (distance d), and the ratio of the bilateral obturator foramen heights (the ratio of obturator heights, ROH), were measured. Improvement in the center-edge angle (CEA) and acetabular index (AI) after SIO was correlated with the LRA, distance d, and ROH. Horizontal and vertical distances from the pubic symphysis to the center of the femoral head were also measured from preoperative and postoperative pelvic radiographs and changes in the position of the femoral head were calculated. For the patients who were followed until skeletal maturity, final radiographic results were also assessed according to the Severin classification. The average improvement of the CEA and AI after SIO was 19.6 and 13.3 degrees, respectively. The average value of the LRA, distance d, and ROH were 30.2 degrees, 4.07 mm, and 73.0%, respectively. The LRA and distance d positively and the ROH negatively correlated with the improvement of the CEA and AI. The center of the femoral head moved an average of 7.06 mm caudally and 3.11 mm medially after SIO. Thirty-six hips (40%) in 36 patients were available for follow-up until skeletal maturity. The radiographic outcome was good (Severin I or II) in 33 hips and poor (Severin III) in 3 hips. Preoperative CEA was relatively smaller in a poor group. Greater improvement of the CEA during postoperative follow-up was observed in a good group. Favorable coverage of the femoral head was obtained after SIO by shifting the center of the femoral head caudally and medially as well as rotating the distal fragment anterolaterally. SIO is a very effective procedure in improvement of the dysplastic acetabulum for the hips with round and spherical femoral head. Therapeutic studies, level III (retrospective study).

The Upper Sacral Nerve Root Tunnel: An Anatomic and Clinical Study

To radiographically demonstrate the upper sacral nerve root tunnel (USNRT) in both cadaveric specimens and a clinical cohort and to quantify its clinical relevance. Level 1 trauma center and anatomy laboratory. Eleven cadaveric pelves and 23 consecutive patients who underwent fluoroscopically assisted iliosacral screw insertions. Cadaveric pelves were fluoroscopically imaged using standard pelvic inlet, outlet, and true lateral sacral views. The course of the USNRT pathway was identified. Then, these tunnels were filled completely with a semisolid radio-opaque agent. The specimens were reimaged after the contrast injection. Clinically, 23 consecutive patients with unstable posterior pelvic ring disruptions were treated using fluoroscopically assisted percutaneous iliosacral screws based on these predictable radiographic landmarks. A total of 44 iliosacral screws were inserted. For the cadaveric portion, the images with contrast were used to identify the USNRTs. For the clinical study, tunnel visualization was determined on all views intraoperatively. Screw placement was documented by postoperative pelvic plain radiographs and computed tomography scan. In the cadaveric specimens, the contrast agent consistently demonstrated the USNRTs on all 3 pelvic radiographic views. In the clinical series, the USNRTs were well visualized on the pelvic outlet image in all 23 patients (100%). Using the inlet image, the USNRTs were visualized in only 5 of 23 patients (21%). On the true lateral sacral views, the USNRTs were seen in 21 of 23 patients (91%). Using these USNRT radiographic landmarks, no iliosacral screw was extraosseous. The USNRTs have a consistent radiographic appearance that is best seen on the pelvic outlet and true lateral sacral views, but their course is best understood when seen on all 3 views. Awareness and understanding of the USNRT, its course, and its radiographic landmarks allow the surgeon to avoid tunnel intrusion by an iliosacral screw.

Surgical advances in periacetabular osteotomy for treatment of hip dysplasia in adults

Hip dysplasia is characterized by an excessively oblique and shallow acetabulum with insufficient coverage of the femoral head. It is a known cause of pain and the development of early osteoarthritis in young adults. The periacetabular osteotomy is the joint-preserving treatment of choice in young adults with symptomatic hip dysplasia. The surgical aim of this extensive procedure is to reorient the acetabulum to improve coverage and eliminate the pathological hip joint mechanics. Intraoperative assessment of the achieved acetabular reorientation is therefore crucial. The "classic" surgical approaches for the periacetabular osteotomy inflict extensive trauma to the tissues and some involve detachment of muscles. The type of surgical approach may affect the occurrence of complications, duration of surgery, intraoperative blood loss, transfusion requirements, and length of hospital stay. The aims of the PhD thesis were I) to assess the outcome of a new, minimally invasive transsartorial approach for periacetabular osteotomy; II) to compare the minimally invasive approach with the previously used "classic" ilioinguinal approach; and III) to assess the reliability of a novel device for intraoperative assessment of the achieved acetabular reorientation. Three studies underly this PhD thesis. In studies I and II, the experience with the minimally invasive and ilioinguinal approaches was retrospectively assessed by database inquiry and evaluation of radiographic material. Data regarding patient demographics, patient history, intraoperative measures and complications was recorded in a validated database. Center-edge and acetabular index angles were measured in preoperative and postoperative pelvic radiographs to assess preoperative dysplasia and the achieved acetabular reorientation. The well-defined study groups consisted of 94 and 263 periacetabular osteotomies in studies I and II, respectively. In study III, intraoperative angle measurements were carried out prospectively in 35 periacetabular osteotomies. The obtained measures (center-edge and acetabular index angles) were compared with those of postoperative pelvic radiographs. Furthermore, a cadaver study was conducted to evaluate intra- and interobserver variability of the device and to assess whether pelvic positioning influenced the variability of measurements. The applied methodology was critically reviewed. Study I--The minimally invasive approach had the following outcome. The mean duration of surgery was 73 min and the median intraoperative blood loss was 250 ml. Blood transfusion was required following 3% of the procedures. There were no cases of moderate or severe technical and neurovascular complications, and the achieved center-edge and acetabular index angles suggest that optimal reorientation can be achieved. Hip joint survival with total hip arthroplasty as the end point was 98% at 4.3 years. Study II--When compared with the outcome of the ilioinguinal approach, the procedures performed by using the minimally invasive approach had a statistically significant shorter duration of surgery, less intraoperative blood loss and hemoglobin reduction, and fewer transfusion requirements. The achieved reorientation was comparable between groups. There were no cases of moderate or severe complications in the minimally invasive group and three cases (3%) of arterial thrombosis in the ilioinguinal group. At follow-up 4.9 years after hip joint surgery, survival rates were 97% in the minimally invasive group and 93% in the ilioinguinal group. Study III--Intraoperatively obtained angle measures differed less than +/- 5 degrees from measurements on postoperative pelvic radiographs, and the intra- and interobserver variability of the device was confined well within +/-5 degrees. Positioning did not influence the variation of angle measurements beyond intraobserver variability of the device. The new minimally invasive transsartorial approach appears to be a safe technique, allowing optimal acetabular reorientation, and seems to minimize tissue trauma. In addition, short-term hip joint survival rate is encouraging. The outcome compares favorably with that of the ilioinguinal approach, and the results support continued use of the minimally invasive approach for periacetabular osteotomy. Optimal reorientation of the acetabulum is crucial in periacetabular osteotomy. The novel measuring device is a potentially helpful tool for intraoperative assessment of center-edge and acetabular index angels. It is simple to use and facilitates repeated reliable angle measurements during acetabular reorientation, making intraoperative radiographs unnecessary. The new, minimally invasive approach and the novel measuring device represent important surgical advances in contemporary periacetabular osteotomy.

Assessment of Magnification of Digital Pelvic Radiographs in Total Hip Arthroplasty Using Templating Software

Templating of pelvic radiographs traditionally involved using implant-company provided acetates which assumed a magnification of 115-120%. With the introduction of digital imaging, many departments are becoming filmless. Templating software has been designed to allow on-screen templating of digital images. Knowledge of the true magnification of the image is required for accurate measurement. Fifty consecutive postoperative pelvic radiographs were analysed using templating software. The implanted component was measured using an assumed magnification factor of 115%. The template image was then reset to the known component size, and the magnification factor was adjusted until the template covered the true component. An assumed magnification factor of 115% oversized the acetabular component by a mean of 6 mm (three component sizes) in all 50 components. The mean true magnification in our department was 127%. Validation of the true magnification produced by a radiology department using templating software is a simple and reproducible technique. It is recommended to all departments using digital images and templating software. Assumption of a magnification factor of 115% risks oversizing components by 6 mm.

The effect of a neck-retaining femoral implant on leg-length inequality following total hip arthroplasty

The aim of this study was to assess whether a femoral component which retained the neck reduced the incidence of leg-length inequality following total hip arthroplasty. A retrospective review was undertaken of 130 consecutive primary total hip arthroplasties performed between April 1996 and April 2004 using such an implant. There were 102 suitable patients for the study. Standardised pre- and post-operative pelvic radiographs were measured by an independent investigator to the nearest millimetre. The leg-length inequality was reduced from a mean pre-operative value of -0.71 cm to a mean of 0.11 cm post-operatively. Of the 102 patients 24 (23.5%) had an equal leg-length post-operatively, and 95 (93.1%) had a leg-length inequality between -1 cm and 1 cm.