Does cup position differ between trabecular metal and titanium cups? A radiographic propensity score matched study of 300 hips.

Background and purpose - The use of trabecular metal cups in primary total hip arthroplasty (THA) is increasing, despite the survival of Continuum cups being slightly inferior compared with other uncemented cups in registries. This difference is mainly explained by a higher rate of dislocation revisions. Cup malpositioning is a risk factor for dislocation and, being made of a highly porous material, Continuum cups might be more difficult to position. We evaluated whether Continuum cups had worse cup positioning compared with other uncemented cups. Patients and methods - Based on power calculation, 150 Continuum cups from 1 center were propensity score matched with 150 other uncemented cups from 4 centers. All patients had an uncemented stem, femoral head size of 32 mm or 36 mm, and BMI between 19 and 35. All operations were done for primary osteoarthrosis through a posterior approach. Patients were matched using age, sex, and BMI. Cup positioning was measured from anteroposterior pelvic radiograph using the Martell Hip Analysis Suite software. Results - There was no clinically relevant difference in mean inclination angle between the study group and the control group (43° [95% CI 41-44] and 43° [CI 42-45], respectively). The study group had a larger mean anteversion angle compared with the control group, 19° (CI 18-20) and 17° (CI 15-18) respectively. Interpretation - Continuum cups had a greater anteversion compared with the other uncemented cups. However, the median anteversion was acceptable in both groups and this difference does not explain the larger dislocation rate in the Continuum cups observed in earlier studies.

Effect of a modular neck hip prosthesis on anteversion and hip rotation in total hip arthroplasty for developmental dysplasia of the hip.

Total hip arthroplasty (THA) is often required to decrease the excessive anatomical femoral anteversion (AA) in developmental dysplasia of the hip. Studies have recommended decreasing the AA via the use of a retroverted modular neck. However, hip rotation after THA may strengthen or weaken the effect of changing the AA. Thus, the present study analyzed the effect of a retroverted neck on AA and hip rotation. Patients who underwent THA using a straight neck (ST group) or a 15° retroverted neck (RV group) in a version changeable dual modular system (Mainstay stem, Kyocera, Kyoto, Japan) were retrospectively reviewed. After matching for age, body mass index, and surgical approach, 44 patients were included in each group. The AA and hip rotation (femoral rotational angle: FRA) were measured on CT images acquired preoperatively and 1 month after THA, and were compared between the groups. The mean ± standard deviation preoperative AA of the ST group (26.1 ± 10.7°) was significantly smaller than that of the RV group (44.2 ± 7.8°) (p < 0.001). In contrast, the postoperative AA did not significantly differ between the groups (ST group 27.5 ± 9.8°, RV group 25.1 ± 8.3°, p = 0.406). The change in FRA after THA did not significantly differ between the groups (ST group - 3.8 ± 9.9°, RV group - 3.5 ± 9.1°, p = 0.841). In conclusion, a 15° retroverted neck was useful in controlling AA in hips with excessive AA, and the change in FRA after THA did not differ between the ST group and the RV group.

A precise method for determining acetabular component anteversion after total hip arthroplasty.

AIMS: Several radiological methods of measuring anteversion of the acetabular component after total hip arthroplasty (THA) have been described. These are limited by low reproducibility, are less accurate than CT 3D reconstruction, and are cumbersome to use. These methods also partly rely on the identification of obscured radiological borders of the component. We propose two novel methods, the Area and Orthogonal methods, which have been designed to maximize use of readily identifiable points while maintaining the same trigonometric principles. PATIENTS AND METHODS: A retrospective study of plain radiographs was conducted on 160 hips of 141 patients who had undergone primary THA. We compared the reliability and accuracy of the Area and Orthogonal methods with two of the current leading methods: those of Widmer and Lewinnek, respectively. RESULTS: The 160 anteroposterior pelvis films revealed that the proposed Area method was statistically different from those described by Widmer and Lewinnek (p < 0.001 and p = 0.004, respectively). They gave the highest inter- and intraobserver reliability (0.992 and 0.998, respectively), and took less time (27.50 seconds (sd 3.19); p < 0.001) to complete. In addition, 21 available CT 3D reconstructions revealed the Area method achieved the highest Pearson's correlation coefficient (r = 0.956; p < 0.001) and least statistical difference (p = 0.704) from CT with a mean within 1° of CT-3D reconstruction between ranges of 1° to 30° of measured radiological anteversion. CONCLUSION: Our results support the proposed Area method to be the most reliable, accurate, and speedy. They did not support any statistical superiority of the proposed Orthogonal method to that of the Widmer or Lewinnek method. Cite this article: Bone Joint J 2019;101-B:1042-1049.

Younger patients with high varus malalignment of the contralateral knee may be candidates for simultaneous bilateral total knee arthroplasty.

PURPOSE: Bilateral total knee arthroplasty (TKA) is being performed more frequently. However, a consensus on whether simultaneous or staged procedures should be performed is not available. This study reviewed the clinical course of contralateral knees in patients who underwent unilateral TKA (UTKA) to determine which patients are candidates for simultaneous bilateral TKA (BTKA). METHODS: One hundred eighty-six patients with osteoarthritis who underwent UTKA at a single hospital between 2006 and 2009 (follow-up mean, 10.1 years) were retrospectively investigated. Age, sex, obesity, contralateral knee pain, Hospital for Special Surgery score, femorotibial angle (FTA), and Kellgren-Lawrence grades at the time of initial surgery were used to evaluate the risk for requiring contralateral TKA. Survival analysis and receiver-operating characteristic (ROC) analysis were performed. RESULTS: Ninety-one patients (48.9%) underwent contralateral TKA. The FTA of the contralateral knee (CFTA) was an independent related factor (hazard ratio, 1.15; p < 0.001), and the CFTA cut-off value for the next surgery was 183° (area under the curve, 0.85; sensitivity, 80.7%; specificity, 76.2%). The 10-year Kaplan-Meier survival rates for the CFTA < 183° group and the CFTA ≥ 183° group were 79.1% and 27.0%, respectively. In the CFTA ≥ 183° group, age was the predictor of future TKA, and elderly patients tended to not require a second procedure. The age cut-off value for the next surgery was 76 years. CONCLUSIONS: Varus deformities in the contralateral knee predicted additional contralateral TKA. Patients with CFTA ≥ 183° and aged 75 years or younger are considered reasonable candidates for simultaneous BTKA. LEVEL OF EVIDENCE: III.

Pelvic positioning in the supine position leads to more consistent orientation of the acetabular component after total hip arthroplasty.

AIMS: This study aims to: determine the difference in pelvic position that occurs between surgery and radiographic, supine, postoperative assessment; examine how the difference in pelvic position influences subsequent component orientation; and establish whether differences in pelvic position, and thereafter component orientation, exist between total hip arthroplasties (THAs) performed in the supine versus the lateral decubitus positions. PATIENTS AND METHODS: The intra- and postoperative anteroposterior pelvic radiographs of 321 THAs were included; 167 were performed with the patient supine using the anterior approach and 154 were performed with the patient in the lateral decubitus using the posterior approach. The inclination and anteversion of the acetabular component was measured and the difference (Δ) between the intra- and postoperative radiographs was determined. The target zone was inclination/anteversion of 40°/20° (± 10°). Changes in the tilt, rotation, and obliquity of the pelvis on the intra- and postoperative radiographs were calculated from Δinclination/anteversion using the Levenberg-Marquardt algorithm. RESULTS: The mean postoperative inclination/anteversion was 40° (± 8°)/23° (± 9°) with Δinclination and/or Δanteversion > ± 10° in 74 (21%). Intraoperatively, the pelvis was anteriorly tilted by a mean of 4° (± 10°), internally rotated by a mean of 1° (± 10°) and adducted by a mean of 1° (± 5°). Having Δinclination and/or Δanteversion > ± 10° was associated with a 3.5 odds ratio of having the acetabular component outside the target zone. A greater proportion of THAs that were undertaken with the patient in the lateral decubitus position had Δinclination and/or Δanteversion > ± 10° (35.3%, 54/153) compared with those in the supine position (4.8%, 8/167; p < 0.001). A greater number of acetabular components were within the target zone in THAs undertaken with the patient in the supine position (72%, 120/167), compared with those in the lateral decubitus position (44%, 67/153; p < 0.001). Intraoperatively, the pelvis was more anteriorly tilted (p < 0.001) and more internally rotated (p = 0.04) when the patient was in the lateral decubitus position. CONCLUSION: The pelvic position is more reliable when the patient is in the supine position, leading to more consistent orientation of the acetabular component. Significant differences in pelvic tilt and rotation are seen with the patient in the lateral decubitus position. Cite this article: Bone Joint J 2018;100-B:1280-8.

The best method for evaluating anteversion of the acetabular component after total hip arthroplasty on plain radiographs.

BACKGROUND: Several radiological methods for measuring the anteversion of the acetabular component after total hip arthroplasty (THA) exist, and no single standardized method has been established. We evaluated the reliability and accuracy of six widely utilized methods (Liaw et al., Lewinnek et al., Widmer, Hassan et al., Ackland et al., and Woo and Morrey) for measuring anteversion on plain radiographs, using a reference standard in the same definition obtained from the PolyWare programme. METHODS: We reviewed 71 patients who underwent primary unilateral THA. The anteversion of the acetabular component was measured on pelvis AP radiographs using five different methods (Liaw et al., Lewinnek et al., Widmer, Hassan et al., and Ackland et al.) and on cross-table lateral radiographs using the method of Woo and Morrey. The values obtained using the PolyWare programme, which determines the anteversion of the acetabular component by edge detection, were regarded as the reference standard. RESULTS: Intra- and inter-observer reliabilities were excellent for all methods using plain radiographs, including the PolyWare programme. The method of Liaw et al. obtained values similar to those obtained using the PolyWare programme and was thus considered accurate (P = 0.447). However, values obtained using the other five methods significantly differed from those obtained using the PolyWare programme and were thus considered less accurate (P < 0.001, P < 0.001, P < 0.001, P = 0.007, and P < 0.001, respectively). CONCLUSION: The method of Liaw et al. is more accurate than other methods using plain radiographs for the measurement of the anteversion of the acetabular component after THA, with reference to the anteversion obtained from the PolyWare programme.

Intra-operative digital imaging: assuring the alignment of components when undertaking total hip arthroplasty.

AIMS: The aims of this study were to examine the rate at which the positioning of the acetabular component, leg length discrepancy and femoral offset are outside an acceptable range in total hip arthroplasties (THAs) which either do or do not involve the use of intra-operative digital imaging. PATIENTS AND METHODS: A retrospective case-control study was undertaken with 50 patients before and 50 patients after the integration of an intra-operative digital imaging system in THA. The demographics of the two groups were comparable for body mass index, age, laterality and the indication for surgery. The digital imaging group had more men than the group without. Surgical data and radiographic parameters, including the inclination and anteversion of the acetabular component, leg length discrepancy, and the difference in femoral offset compared with the contralateral hip were collected and compared, as well as the incidence of altering the position of a component based on the intra-operative image. RESULTS: Digital imaging took a mean of five minutes (2.3 to 14.6) to perform. Intra-operative changes with the use of digital imaging were made for 43 patients (86%), most commonly to adjust leg length and femoral offset. There was a decrease in the incidence of outliers when using intra-operative imaging compared with not using it in regard to leg length discrepancy (20% versus 52%, p = 0.001) and femoral offset inequality (18% versus 44%, p = 0.004). There was also a difference in the incidence of outliers in acetabular inclination (0% versus 7%, p = 0.023) and version (0% versus 4%, p = 0.114) compared with historical results of a high-volume surgeon at the same centre. CONCLUSION: The use of intra-operative digital imaging in THA improves the accuracy of the positioning of the components at THA without adding a substantial amount of time to the operation. Cite this article: Bone Joint J 2018;100B(1 Supple A):36-43.

Acetabular Global Insufficiency in Patients with Down Syndrome and Hip-Related Symptoms: A Matched-Cohort Study.

BACKGROUND: The etiology of hip instability in Down syndrome is not completely understood. We investigated the morphology of the acetabulum and femur in patients with Down syndrome and compared measurements of the hips with those of matched controls. METHODS: Computed tomography (CT) images of the pelvis of 42 patients with Down syndrome and hip symptoms were compared with those of 42 age and sex-matched subjects without Down syndrome or history of hip disease who had undergone CT for abdominal pain. Each of the cohorts had 23 male and 19 female subjects. The mean age (and standard deviation) in each cohort was 11.3 ± 5.3 years. The lateral center-edge angle (LCEA), acetabular inclination angle (IA), acetabular depth-width ratio (ADR), acetabular version, and anterior and posterior acetabular sector angles (AASA and PASA) were compared. The neck-shaft angle and femoral version were measured in the patients with Down syndrome only. The hips of the patients with Down syndrome were further categorized as stable (n = 21) or unstable (n = 63) for secondary analysis. RESULTS: The hips in the Down syndrome group had a smaller LCEA (mean, 10.8° ± 12.6° compared with 25.6° ± 4.6°; p < 0.0001), a larger IA (mean, 17.4° ± 10.3° compared with 10.9° ± 4.8°; p < 0.0001), a lower ADR (mean, 231.9 ± 56.2 compared with 306.8 ± 31.0; p < 0.0001), a more retroverted acetabulum (mean acetabular version as measured at the level of the centers of the femoral heads [AVC], 7.8° ± 5.1° compared with 14.0° ± 4.5°; p < 0.0001), a smaller AASA (mean, 55.0° ± 9.9° compared with 59.7° ± 7.8°; p = 0.005), and a smaller PASA (mean, 67.1° ± 10.4° compared with 85.2° ± 6.8°; p < 0.0001). Within the Down syndrome cohort, the unstable hips showed greater femoral anteversion (mean, 32.7° ± 14.6° compared with 23.6° ± 10.6°; p = 0.002) and worse global acetabular insufficiency compared with the stable hips. No differences between the unstable and stable hips were found with respect to acetabular version (mean AVC, 7.8° ± 5.5° compared with 7.6° ± 3.8°; p = 0.93) and the neck-shaft angle (mean, 133.7° ± 6.7° compared with 133.2° ± 6.4°; p = 0.81). CONCLUSIONS: Patients with Down syndrome and hip-related symptoms had more retroverted and shallower acetabula with globally reduced coverage of the femoral head compared with age and sex-matched subjects. Hip instability among those with Down syndrome was associated with worse global acetabular insufficiency and increased femoral anteversion, but not with more severe acetabular retroversion. No difference in the mean femoral neck-shaft angle was observed between the stable and unstable hips in the Down syndrome cohort. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Acetabular and Femoral Anteversions in Standing Position are Outside the Proposed Safe Zone After Total Hip Arthroplasty.

BACKGROUND: Although most hip dislocations occur in either standing or sitting position, the safe zone for implant position is defined for the supine position. Our goal was to determine preoperative and postoperative pelvis and hip orientations and whether the safe zone defined in supine position can be used to assess standing radiographs. METHODS: Preoperative and postoperative three-dimensional EOS images were assessed in 66 total hip arthroplasty patients. None of the patients had dislocation within the follow-up period (12-36 months). The acetabular anteversion (both anterior pelvic plane [APP] and patient functional plane) and the femoral anteversion were measured. The sacral slope, pelvic version, pelvic inclination, and pelvic incidence were also measured. RESULTS: Acetabular anteversion increased postoperatively in both APP and patient functional plane (P <.001). Femoral neck anteversion decreased postoperatively (P =.0942). Sacral slope was 42.4° (-25.9° to 24°) preoperatively compared with 40.3° (-4.1° to 64.2°) postoperatively (P =.013). Pelvic version changed from 15.2° (-10.4° to 43.8°) to 17.2° (-6° to 46.7°; P = 0.008). Pelvic inclination was 1.12° (-25.9° to 24°) before total hip arthroplasty and -1.2° (-40.7° to 23.4°) postoperatively (P =.005). CONCLUSION: The acetabular and femoral implant orientations in standing position reside out of the safe zone in most patients. The APP is not vertical in standing position in most patients due to anterior or posterior pelvic tilt. The proposed safe zone in supine position may not be a useful measure in the assessment of standing radiographs of patients with significant anterior or posterior pelvic tilt. LEVEL OF EVIDENCE: Level IV, therapeutic case series study.

Femoral malrotation after surgical treatment of femoral shaft fractures in children: a retrospective CT-based analysis.

BACKGROUND: Rotational malalignment is an important and not always avoidable complication after surgical treatment of femoral shaft fractures. The purpose of this study was to determine the incidence of rotational malalignment in children after surgical treatment of femoral shaft fractures and to identify potential patient- and treatment-related risk factors based on data obtained from CT scans. METHODS: We conducted a retrospective analysis of all patients aged less than 15 years with femoral shaft fractures admitted to our level 1 trauma centre between January 2004 and July 2014. Patients having obtained postoperative CT scans were included for the determination of rotational malalignment. A difference of greater than 15° in femoral torsion between both legs was considered as clinically relevant. Additionally, demographic data and clinical information such as fracture type, treatment method, fluoroscopy time and operating time were reviewed. RESULTS: A total of 24 patients were enrolled in this study. Clinically relevant femoral malrotation was identified in 10 patients (41.6%). Surgical revision was performed in 7 patients (29.2%). There was no association between the type of surgical procedure, age and the incidence and/or amount of femoral malrotation. CONCLUSIONS: The data suggest that relevant femoral malrotation is an evident problem after surgical treatment of femoral shaft fractures in children that requires critical postoperative assessment. LEVEL OF EVIDENCE: Level III, retrospective study.

Increased Femoral Anteversion Influence Over Surgically Treated Recurrent Patellar Instability Patients.

PURPOSE: To verify the influence that increased femoral anteversion (FA) has on patients with recurrent patellar instability (RPI) treated by anteromedialization tibial tubercle osteotomy (TTO) combined with medial patellofemoral ligament reconstruction (MPFLR) and to present the midterm outcomes of these patients. METHODS: From January 2008 to August 2013, skeletally mature patients with RPI and tibial tubercle (TT)-trochlear groove (TG) ≥ 17 mm who underwent anteromedialization TTO combined with MPFLR were evaluated for J sign, patellar glide, apprehension test, increased FA, Caton index, trochlea dysplasia, TT-TG, Kujala, International Knee Documentation Committee subjective knee evaluation form, and Tegner. Increased FA was determined clinically by a difference of more than 30° between hip internal and external rotation, 70° or more of hip internal rotation, and 30° or more of femoral neck anteversion. A subgroup analysis involving increased FA was made. RESULTS: Forty-eight patients composed the study group. Mean follow-up was 41.5 ± 11.05 months. The J-sign was present in 86% before surgery and none postoperatively (P < .001). All patients had a positive apprehension test or a patellar luxation at the patellar glide test rated as grade 4 before surgery. After surgery, the mean glide was 1.29 ± 0.45 with no apprehension (P < .001). Increased FA was present in 18.7%. Caton index before surgery was 1.11 ± 0.21 and 0.99 ± 0.11 postoperatively (P = .004). Trochlea dysplasia was present in all patients. TT-TG preoperatively was 20.77 ± 2.12 mm and 11.33 ± 1.24 mm postoperatively (P < .001). Functional scores improved preoperatively to postoperatively (P < .001) with Kujala and International Knee Documentation Committee means: 59.08 to 84.37; 52.6 to 85.5, respectively. Tegner preinjury score was 5.4 and postoperatively was 5.2 (P = .01). Increased FA group had worse Kujala compared with the normal FA group and worse Kujala improvement: 77.7 and 85.89 (P = .012), and 21.7 and 26.1, respectively (P < .001). CONCLUSIONS: Increased FA in patients with RPI had a negative effect on the outcome of anteromedialization TTO combined with MPFLR. Combined anteromedialization TTO and MPFLR had good functional midterm outcomes in treating patients with RPI and TT-TG ≥ 17 mm. LEVEL OF EVIDENCE: Level III, comparative study.

The Relationship Between Early-Stage Knee Osteoarthritis and Lower-Extremity Alignment, Joint Laxity, and Subjective Scores of Pain, Stiffness, and Function.

CONTEXT: Knee osteoarthritis (OA) is a debilitating disease that affects an estimated 27 million Americans. Changes in lower-extremity alignment and joint laxity have been found to redistribute the medial and/or lateral loads at the joint. However, the effect that changes in anteroposterior knee-joint laxity have on lower-extremity alignment and function in individuals with knee OA remains unclear. OBJECTIVE: To examine anteroposterior knee-joint laxity, lower-extremity alignment, and subjective pain, stiffness, and function scores in individuals with early-stage knee OA and matched controls and to determine if a relationship exists among these measures. DESIGN: Case control. SETTING: Sports-medicine research laboratory. PARTICIPANTS: 18 participants with knee OA and 18 healthy matched controls. INTERVENTION: Participants completed the Western Ontario McMaster (WOMAC) osteoarthritis questionnaire and were tested for total anteroposterior knee-joint laxity (A-P) and knee-joint alignment (ALIGN). MAIN OUTCOME MEASURES: WOMAC scores, A-P (mm), and ALIGN (°). RESULTS: A significant multivariate main effect for group (Wilks' Λ = 0.30, F7,26 = 8.58, P < .0001) was found. Knee-OA participants differed in WOMAC scores (P < .0001) but did not differ from healthy controls on ALIGN (P = .49) or total A-P (P = .66). No significant relationships were identified among main outcome measures. CONCLUSION: These data demonstrate that participants with early-stage knee OA had worse pain, stiffness, and functional outcome scores than the matched controls; however, ALIGN and A-P were no different. There was no association identified among participants' subjective scores, ALIGN, or A-P measures in this study.

Ipsilateral varus knee alignment correlates with increased femoral stem anteversion in primary total hip arthroplasty.

PURPOSE: The purpose of this study was to evaluate whether the ipsilateral knee alignment secondary to knee osteoarthritis affect positioning of the femoral component anteversion during total hip arthroplasty. METHODS: Preoperative and postoperative computed tomography-based 3-D femoral models were reconstructed for 20 total hip arthroplasty patients. Prosthetic femoral stem and native femoral anteversion was measured and compared. RESULTS: An average increase by 4.5° ± 8.1° in femoral anteversion was found following total hip arthroplasty (p = 0.02). Strong positive correlation was found between the knee varus angle and the changes in femoral anteversion (R = 0.87, p<0.0001). The knee alignment was an independent factor for predicting the intraoperative positioning of femoral stem anteversion. CONCLUSIONS: The ipsilateral knee varus deformity should be considered to optimise the femoral component position during contemporary total hip arthroplasty.

Acetabular Anteversion Changes Due to Spinal Deformity Correction: Bridging the Gap Between Hip and Spine Surgeons.

BACKGROUND: Hip osteoarthritis often coexists with adult spinal deformity, an abnormality in which sagittal spinopelvic malalignment is present. Debate exists whether to perform spinal realignment correction or total hip arthroplasty first. Hip extension and pelvic tilt are important compensatory mechanisms in the setting of sagittal spinopelvic malalignment and change after spinal realignment. We performed this study to evaluate the effect that the spinal realignment surgical procedure has on acetabular anteversion. METHODS: This study is a retrospective review of a multicenter, prospective, consecutive database of patients with adult spinal deformity who underwent surgical spinal realignment. Only patients who already had undergone a total hip arthroplasty prior to the spinal realignment procedure were retained for analysis. Patients were excluded if they had insufficient imaging or large-head, metal-on-metal bearings or they had undergone revision total hip arthroplasty in the study period. Acetabular anteversion was calculated via the ellipse method on a standing, posterior-anterior, 90-cm radiograph with a well-centered pelvis. Anteversion was measured preoperatively and at six weeks or three months after the spinal realignment procedure. Spinopelvic parameters measured included pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, T1 pelvic angle, sagittal vertical axis, T1-spinopelvic inclination, and thoracic kyphosis. RESULTS: Forty-one hips (thirty-three patients) were identified. Acetabular anteversion significantly reduced (p < 0.001) after spinal correction by mean change of -4.96° (range, -22.32° to +2.36°). The change in anteversion correlated with the changes in sagittal pelvic orientation (0.828 for the pelvic tilt, -0.757 for the sacral slope, and -0.691 for the lumbar lordosis) and global spinopelvic alignment (0.579 for the sagittal vertical axis and 0.585 for the T1 pelvic angle). Regression analysis revealed that anteversion decreased by 1° for each of the following spinopelvic parameter changes (p < 0.001): 1.105° for spinopelvic tilt, 1.032° for sacral slope, and 3.163° for lumbar lordosis. CONCLUSIONS: Patients with spinopelvic malalignment had a high prevalence of excessively anteverted acetabular components. Sagittal spinal correction following total hip arthroplasty resulted in reduced acetabular anteversion, which may have implications for stability. Changes in anteversion are most closely related to changes in pelvic tilt in an almost one-to-one ratio.

Evaluation of radiological methods of assessing cup anteversion in total hip replacement.

STUDY DESIGN: Prospective clinical study. BACK GROUND: In total hip replacement, the placement of the cup is critical as inaccurate placement can cause impingement, accelerated wear and dislocations. The position of the cup is assessed by abduction and anteversion. There are many radiological methods available for this purpose, while the reliability and validity of the methods have not been adequately done. Calculation by CT method is a gold standard. The aim of study was to evaluate the reliability and validity of all the methods. METHODS: In 30 hips of 25 consecutive patients, 13 females and 12 males who underwent primary total hip replacement in our institution, the component version in all the five radiological methods was calculated and compared with CT evaluation of angles. The intra- and interobserver reliabilities were assessed. RESULTS: Average CT measurement was 23.28 for anteversion. Lewinnek, Liaw, Hassan, Widmer and Ritun methods had average deviation of 4.330, 4.390, 4.880, 6.840 and 6.220, respectively. All the radiographic and CT methods had excellent intra- and interobserver reliabilities (C.I. 0.894-0.960 and 0.861-0.953). All the methods except Widmer had a significant validity against CT. CONCLUSION: Plain X-rays (AP) are reliable for measuring cup anteversion. Lewinnek, Liaw, Riten and Hassans methods for calculation of cup anteversion are closer to CT in accuracy (p value >0.05). Widmer method varies significantly (p value <0.05) from CT.

Three-dimensional computed tomography for determination of femoral anteversion in a cerebral palsy model.

BACKGROUND: Previous investigation has proven 3-dimensional (3D) computed tomography (CT) to be a poor method of assessing femoral anteversion in patients with cerebral palsy. However, new advancements in CT software yield the potential to improve upon those dated results. METHODS: CT was performed on 9 femoral models with varying amounts of anteversion (20 to 60 degrees) and varying neck-shaft angles (120 to 160 degrees). Each model was scanned in 2 holding devices. One holder placed the femur in an ideal position relative to the gantry. The other placed the femur in flexion, adduction, and internal rotation simulating a common lower extremity posture in cerebral palsy. Femoral anteversion was measured on 3D reconstructions by 4 observers on 2 separate occasions. Interobserver and intraobserver reliability, accuracy, and the effect of increasing neck-shaft angle of the measurements were examined and compared with previously published data using the same models. RESULTS: Pearson correlation coefficients between first and second measurements by the same examiner were all above 0.96 regardless of positioning of the femur in the gantry. The correlation coefficients among all examiners were 0.97 regardless of positioning of the femur in the gantry. Accuracy in measurements was comparable using 3D CT techniques with mean differences between the normal and cerebral palsy-positioned models of <3.6 degrees (SD, 3.1 to 3.3 degrees). Accuracy of the study's 3D CT technique in measuring femoral anteversion in cerebral palsy-positioned femurs was significantly more accurate than that of 2D CT (P<0.0001). CONCLUSIONS: Recent improvements in processing software and 3D reconstruction have made assessment of femoral anteversion with 3D CT accurate through the studied range of anteversion and neck-shaft angles. Using this technique, high intraobserver and interobserver reliability in the determination of femoral anteversion can be expected regardless of neck-shaft angle or postural deformity. LEVEL OF EVIDENCE: Level II.

The clinical impact of orthotic correction of lower limb rotational deformities in children with cerebral palsy: a randomized controlled trial.

OBJECTIVE: This study aimed to evaluate the effectiveness of a static ground reaction ankle foot orthosis and strapping system on improving gait parameters in children with spastic diplegic cerebral palsy. SETTING: The current study was conducted at the physical therapy faculty of Cairo University, Egypt. SUBJECTS: This study included 57 children of both sexes, aged 6 to 8 years. STUDY DESIGN: Three-armed randomized control trial. INTERVENTION: Participants in all groups received a traditional neuro-developmental physical therapy program that included standing and gait training exercises. Children in group A performed the training program without any orthotic management, in group B with the TheraTogs strapping system, and in group C with the TheraTogs strapping system and static ground reaction ankle foot orthoses. Children underwent treatment for two hours daily, except on weekends, for twelve successive weeks. MAIN MEASURE: Gait speed, cadence, stride length, and hip and knee flexion angles in the mid-stance phase were evaluated pre-and post-treatment using a three-dimensional motion analysis system (pre-reflex system). RESULTS: Statistically significant differences were recorded among the three groups post-treatment in gait speed, cadences, and stride length. The P-values for these variable differences were 0.03, 0.011, and 0.001 respectively. Significant post-treatment differences were also recorded for bilateral hip-and knee-flexion angles. For all measured parameters, better significant results were registered for group C than for the other groups. CONCLUSION: Orthotic intervention composed of a static ground reaction ankle foot orthosis combined with the TheraTogs strapping system improves gait more than conventional treatment with or without TheraTogs in children with spastic diplegic cerebral palsy.

An analysis of the best method for evaluating anteversion of the acetabular component after total hip replacement on plain radiographs.

Several radiological methods of measuring anteversion of the acetabular component after total hip replacement (THR) have been described. These studies used different definitions and reference planes to compare methods, allowing for misinterpretation of the results. We compared the reliability and accuracy of five current methods using plain radiographs (those of Lewinnek, Widmer, Liaw, Pradhan, and Woo and Morrey) with CT measurements, using the same definition and reference plane. We retrospectively studied the plain radiographs and CT scans in 84 hips of 84 patients who underwent primary THR. Intra- and inter-observer reliability were high for the measurement of inclination and anteversion with all methods on plain radiographs and CT scans. The measurements of inclination on plain radiographs were similar to the measurements using CT (p = 0.043). The mean difference between CT measurements was 0.6° (-5.9° to 6.8°). Measurements using Widmer's method were the most similar to those using CT (p = 0.088), with a mean difference between CT measurements of -0.9° (-10.4° to 9.1°), whereas the other four methods differed significantly from those using CT (p < 0.001). This study has shown that Widmer's method is the best for evaluating the anteversion of the acetabular component on plain radiographs.

A new method for the measurement of anteversion of the acetabular cup after total hip arthroplasty.

OBJECTIVE: Many methods of determining the anteversion of the acetabular cup have been described in the literature. The advantages and disadvantages of each of these methods are discussed in this paper. We present a new method of measuring the acetabular anteversion at the anteroposterior hip. MATERIALS AND METHODS: The formula designed by the authors was anteversion angle (α) = arc sin |PK|/√ |AK| × |BK|. The formula was tested using the AutoCAD software, and an experimental study was conducted to evaluate the accuracy. Three groups were created, and 16 X-ray images were taken and coded. Ten orthopaedic surgeons measured the acetabular anteversion from these X-rays using our formula. RESULTS: The results in Group 1 were closer to the actual value; in contrast, the results in Group 2 differed from the actual values. The results in Group 3 were as close to the actual anteversion values as were those in Group 1. CONCLUSION: Developments in technology often bring an increase in complications. Despite newly developed surgical methods and technology, the position of the acetabular cup is still used to determine the results of a total hip arthroplasty. Our method is simple, cost-effective and achieves almost 100 % accuracy.

Femoral derotational osteotomy: surgical indications and outcomes in children with cerebral palsy.

Excessive femoral anteversion is common among children with cerebral palsy, and is, frequently treated by a femoral derotational osteotomy (FDO). It is important to understand surgical, indications for FDO, and the impact of these indications on the treatment outcomes. The Random Forest algorithm was used to objectively identify historical surgical indications in a large retrospective, cohort of 1088 limbs that had previously undergone single-event multi-level surgery. Treatment, outcome was based on transverse plane kinematics obtained from three-dimensional gait analysis. The, classifier effectively identified the historic indications (accuracy = .85, sensitivity = .93, specificity = .69, positive predictive value = .86, negative predictive value = .82), and naturally divided limbs into four, clusters: two homogeneous +FDO clusters (with/without significant internal hip rotation during gait), one homogeneous -FDO cluster, and a mixed cluster. Concomitant surgeries were similar among the, clusters. Limbs with excessive anteversion and internal hip rotation during gait had excellent outcomes, in the transverse plane. Limbs with excessive anteversion but only mild internal hip rotation had good, outcomes at the hip level; but a significant number of these limbs ended up with an excessive external, foot progression angle. The Random Forest algorithm was highly effective for identifying and, organizing historic surgical indications. The derived criteria can be used to give surgical decision making, guidance in a majority of limbs. The results suggest that limbs with anteversion and significant, internal hip rotation during gait benefit from an FDO, but limbs with excessive anteversion and only, mild internal hip rotation are at risk of developing an excessive external foot progression angle.