Femoral anteversion does not predict redislocation in children with hip dysplasia treated by closed reduction.

PURPOSE: Increased femoral anteversion can be associated with hip instability, redislocation after closed reduction, and subsequent early degenerative arthritis. Our study compared proximal femoral anteversion of affected and unaffected sides of patients with unilateral developmental dysplasia of the hip (DDH) on two-dimensional computed tomography. The primary aim was to evaluate whether femoral anteversion at the time of treatment affected the outcome of patients with unilateral DDH treated by closed reduction. METHODS: A retrospective review of 89 patients (82 females; 53 left; mean age: 26.6 months) with unilateral DDH was performed. Anteversion angle (AA) of the femur and acetabular index (AI) of both affected (AAa; AIa) and unaffected (AAu; AIu) hips were measured on two-dimensional CT scan performed no more than seven days prior to the index surgical procedure. RESULTS: Among the 89 patients, 50 underwent closed reduction (56.2%), 38 underwent open reduction with or without pelvic osteotomy (42.7%), and one patient refused treatment (1.1%). Overall, the mean AAa was 28.1° ± 10.2° (range: 6.3°-54°) and mean AAu was 25.2° ± 9.9° (range: 1.9°-52.5°) (t = 3.2, p = 0.002). Tönnis type 2 hips did not show any statistically significant difference between AAa and AAu (p = 0.386), while Tönnis types 3 and 4 hips had significantly higher AAa than did AAu (t = 3.7, p = 0.001). There were significant correlations between age and AAa (coefficient = 0.4; p < 0.001) and AAu (coefficient = 0.304; p = 0.004). Correlation analysis showed that AIa did not improve with age in any Tönnis group (r: - 0.24, p = 0.823; F = 0.039, p = 0.962). AAa, AIa, AAD, AID, and Tönnis grade distribution were similar in patients with good (no redislocation) and poor outcomes (redislocation) (p > 0.05). CONCLUSION: In patients with unilateral DDH, anteversion angle (AA) was found to be significantly different between affected and unaffected sides. However, the difference had very limited or no clinical significance, as redislocation/sub-luxation was not influenced by AA values.

Femoral-Acetabular Mating: The Effect of Femoral and Combined Anteversion on Cross-Linked Polyethylene Wear.

BACKGROUND: Cross-linked polyethylene (XLPE) has generally low rates of wear and osteolysis at 10 years, but component position may become important with longer follow-up. At 5-13 years, neither acetabular component lateral opening angle nor version were significantly correlated to wear. In the present study, we analyzed the effects of femoral anteversion and combined anteversion on XLPE wear. METHODS: Forty-two well-functioning primary total hip arthroplasties in 36 patients, performed by a single surgeon via a posterior approach, were followed for a minimum of 5 years (mean, 7.1 years; range, 5.0-10.3). All hips had a modular, XLPE liner with a ≥36-mm bearing. Femoral anteversion was measured on the modified Budin view. Wear was measured on radiographs using a validated, computer-assisted, edge-detection-based algorithm. The mean lateral opening angle was 40.4° (range, 22.6°-50.3°). The mean acetabular version was 19.1° (range, 11.3°-27.5°). Neither of these variables was significantly correlated to wear. Effects of femoral anteversion and combined anteversion on XLPE wear were assessed using linear and polynomial regression analysis. RESULTS: Femoral anteversion (mean, 18.4°; range, 6.8°-30.7°) was significantly correlated to linear wear (mean, 0.06 mm/y; range, 0-0.16), showing an inverse parabolic relationship with the least wear occurring at 18.2° (P = .02). Combined anteversion (mean, 37.2°; range, 21.8°-54.3°) showed a similar significant relationship with the least wear at 38.1° (P < .001). Based on regression, combined anteversion between 24.6° and 50.4° resulted in linear wear rates less than 0.1 mm/y. CONCLUSION: To the authors' knowledge, this is the first study to identify femoral anteversion as an independent factor influencing XLPE wear, with least wear occurring around 18°. At 5-10 years, average linear wear of XLPE is below 0.1 mm/y over a 25°-50° range of combined anteversion, with the least wear around 38°. Femoral-acetabular mating is a product of both components. Femoral component version and combined anteversion had a greater effect on wear than acetabular component lateral opening angle. Additional studies are warranted, but these results indicate that the sensitivity of wear studies is increased with version assessments.

Knee Pain and Activity Outcomes After Femoral Derotation Osteotomy for Excessive Femoral Anteversion.

BACKGROUND: Excessive femoral anteversion is a developmental condition that can become symptomatic into adolescence and manifest as anterior knee pain, tripping, and or problems with sports. Femoral derotational osteotomy about an antegrade intramedullary nail (IMN) is an accepted option to treat this condition. This is the first report of the clinical and functional outcomes of treatment of excessive anteversion with femoral derotational osteotomy stabilized with an IMN. METHODS: We prospectively enrolled 28 consecutive patients between 2013 and 2014 who underwent derotational osteotomy. Physical examination measures were used to calculate the amount of angular correction with focus on internal and external rotation of the hip, as well as the trochanteric prominence angle test of femoral anteversion. The International Knee Documentation Committee-9, Marx, and Tegner activity scales were 3 patient-reported outcomes recorded. RESULTS: After femoral derotation osteotomy over an IMN, femoral anteversion, as measured by the trochanteric prominence angle, improved an average of 29 degrees (P<0.0001). At 1-year minimum follow-up, 22 of 28 subjects (78.5%) demonstrated a mean significant improvement of 13 points for International Knee Documentation Committee-9 (SD=15.4, P=0.0007), which surpassed the level of minimal clinically important change. Furthermore, the Tegner inventory scores for the cohort improved by an average of 1.9 activity levels (SD=2.4, P=0.0012). CONCLUSIONS: For adolescents with symptomatic excessive femoral anteversion, derotational osteotomy over an IMN offers a reliable surgical option that provides predictable deformity correction and significant improvements in both function and pain scales. LEVELS OF EVIDENCE: Level II-prospective, consecutive, nonrandomized, internally controlled cohort study.

Spinopelvic parameter changes and low back pain improvement due to femoral neck anteversion in patients with severe unilateral primary hip osteoarthritis undergoing total hip replacement.

PURPOSE: The study of the interrelation between hip and spine disorders is gaining increasing importance in the last years, but the link between Hip Osteoarthritis (HOA) and Low Back Pain (LBP) remains still unclear. Aim of the study is to assess the relationship between Femoral Neck Anteversion (FNA), LBP, and spinopelvic parameters in patients undergoing Total Hip Replacement (THR) for unilateral severe primary HOA. MATERIALS AND METHODS: 91 patients were recruited. Inclusion criteria were: grade 5 or 6 unilateral HOA, according to Turmezei, and Harris Hip score (HHS) <60. Exclusion criteria were: secondary hip osteoarthritis (dysplasia of the hip, rheumatoid arthritis, and ankylosing spondylitis); previous surgery of the spine, hip or knee; scoliosis with a Cobb angle greater than 10°; spondylolisthesis; history of spine fractures; previous bone tuberculosis or any spine infections; any contraindications to CT; BMI >30. Patients were divided into two homogeneous Groups according to the presence (Group-A) or not of concomitant LBP (Group-B). All patients underwent preoperatively a hip CT scan to evaluate FNA, Acetabular Anteversion (AA), and Combined Anteversion (CA = FNA + AA). ΔFNA, ΔAA and ΔCA were calculated as the differences between the arthritic hip and the normal hip angles in each Group. Full spinal X-rays in upstanding position were performed before (baseline) and 6 months after THR (follow-up) to calculate spinopelvic parameters. The health-related quality of life (HRQoL) was evaluated at baseline and at follow-up using Visual Analogue Scale (VAS), HHS, Oswestry Disability Index (ODI), Roland-Morris Disability Questionnaire (RM), and Short-Form Health Survey (SF-36). The intra-group and inter-group variability were assessed using, respectively, paired and unpaired t tests. At baseline, the association between HRQoL scores and ΔFNA, ΔAA, and ΔCA was analysed by the Pearson correlation test. RESULTS: At baseline, in Group-A, there was a significant difference between arthritic FNA and normal hip FNA, while no differences were found in AA between the two hips. A close correlation was observed between ΔFNA and Spine-VAS (r = 0.788), ODI (r = 0.824), and RM (r = 0.775). In Group-B, there was not a significant difference in FNA and AA between the two hips. At recruitment, in Group-A patients, we recorded a higher LL, SS, PI, SVA(C7), and a lower PT and T1-SPI compared with Group-B subjects. Six months after THR, in Group-A, an improvement of all clinical scores was recorded, as well as, a significant reduction of SS, LL, T1PA, and SVA(C7) and an increment of PT. In Group-B, at follow-up, an improvement of HHS, Hip-VAS, and SF-36 was recorded, while the changes in spinopelvic parameters were not significant. CONCLUSIONS: Patients with concomitant unilateral HOA and LBP showed a marked anteverted FNA in the arthritic hip and a spinopelvic misalignment. After THR, a relief of both hip and low back pain and a change in spinopelvic parameters is observed.

Effects of intertrochanteric osteotomy plane and preoperative femoral anteversion on the postoperative morphology of the proximal femur in transtrochanteric anterior rotational osteotomy: 3D CT-based simulation study.

BACKGROUND: Transtrochanteric anterior rotational osteotomy (ARO) is joint-preserving surgery for patients with osteonecrosis of the femoral head (ONFH). During ARO, femoral neck-shaft varus angulation by changing intertrochanteric osteotomy plane is often designed to obtain a sufficient postoperative intact ratio. However, the effect of intertrochanteric osteotomy plane on postoperative femoral anteversion has not been well examined. Therefore, we performed a simulation study of ARO to determine how intertrochanteric osteotomy plane and preoperative femoral anteversion affect both femoral neck-shaft varus angle and postoperative femoral anteversion. HYPOTHESIS: Both femoral neck-shaft varus angle and postoperative femoral anteversion are predicted by intertrochanteric osteotomy plane and preoperative femoral anteversion in ARO. MATERIALS AND METHODS: Using CT-data obtained from 10 hips in 10 patients with ONFH, ARO was simulated. On anteroposterior view, basic intertrochanteric osteotomy line (AP-view line) was defined as the perpendicular line to the femoral neck axis. On lateral view, basic intertrochanteric osteotomy line (lateral-view line) made through the cut surface of greater trochanter was defined as the perpendicular line to the lateral axis of the femur. By changing either AP-view or lateral-view line, 49 ARO models/hip were produced, in which femoral neck-shaft varus angle and postoperative femoral anteversion were assessed. RESULTS: With increase in the vertically-inclined degree of AP-view line, both neck-shaft varus angle and postoperative femoral anteversion increased. With increase in the posteriorly-tilted degree of lateral-view line, neck-shaft varus angle increased, whereas postoperative femoral anteversion decreased. The approximation equations based on the multiple regression analyses were as follows: neck-shaft varus angle≈vertically-inclined degree of AP-view line×0.9+posteriorly-tilted degree of lateral-view line×0.8+preoperative femoral anteversion×0.7; postoperative femoral anteversion≈vertically-inclined degree of AP-view line×1.1-posteriorly-tilted degree of lateral-view line×0.8. DISCUSSION: The postoperative morphology of proximal femur was nearly defined by intertrochanteric osteotomy plane with preoperative femoral anteversion, which is useful for preoperative planning in terms of both achieving a sufficient postoperative intact ratio and maintaining femoral anteversion. LEVEL OF EVIDENCE: Level IV case series without control group.

Native femoral anteversion should not be used as reference in cementless total hip arthroplasty with a straight, tapered stem: a retrospective clinical study.

BACKROUND: Improper femoral and acetabular component positioning can be associated with instability, impingement, component wear and finally patient dissatisfaction in total hip arthroplasty (THA). The concept of "femur first"/"combined anteversion", incorporates various aspects of performing a functional optimization of the prosthetic stem and cup position of the stem relative to the cup intraoperatively. In the present study we asked two questions: (1) Do native femoral anteversion and anteversion of the implant correlate? (2) Do anteversion of the final broach and implant anteversion correlate? METHODS: In a secondary analysis of a prospective controlled trial, a subgroup of 55 patients, who underwent computer-assisted, cementless THA with a straight, tapered stem through an anterolateral, minimally invasive (MIS) approach in a lateral decubitus position were examined retrospectivly. Intraoperative fluoroscopy was used to verify a "best-fit" position of the final broach. An image-free navigation system was used for measurement of the native femoral version, version of the final broach and the final implant. Femoral neck resection height was measured in postoperative CT-scans. This investigation was approved by the local Ethics Commission (No.10-121-0263) and is a secondary analysis of a larger project (DRKS00000739, German Clinical Trials Register May-02-2011). RESULTS: The mean difference between native femoral version and final implant was 1.9° (+/- 9.5), with a range from -20.7° to 21.5° and a Spearman's correlation coefficient of 0.39 (p < 0.003). In contrast, we observed a mean difference between final broach and implant version of -1.9° (+/- 3.5), with a range from -12.7° to 8.7° and a Spearman's correlation coefficient of 0.89 (p < 0.001). In 83.6 % (46/55) final stem version was outside the normal range as defined by Tönnis (15-20°). The mean femoral neck resection height was 7.3 mm (+/- 5.6). There was no correlation between resection height and version of the implant (Spearman's correlation coefficient 0.14). CONCLUSION: Native femoral version significantly differs from the final anteversion of a cementless, straight, tapered stem and therefore is not a reliable reference in cementless THA. Measuring anteversion of the final "fit and fill" broach is a feasible assistance in order to predict final stem anteversion intraoperatively. There is no correlation between femoral neck resection height and version of the implant.

Radiologic Outcomes According to Varus Deformity in Minimally Invasive Surgery Total Knee Arthroplasty.

PURPOSE: To identify the accuracy of postoperative implant alignment in minimally invasive surgery total knee arthroplasty (MIS-TKA), based on the degree of varus deformity. MATERIALS AND METHODS: The research examined 627 cases of MIS-TKA from November 2005 to December 2007. The cases were categorized according to the preoperative degree of varus deformity in the knee joint in order to compare the postoperative alignment of the implant: less than 5° varus (Group 1, 351 cases), 5° to less than 10° varus (Group 2, 189 cases), 10° to less than 15° varus (Group 3, 59 cases), and 15° varus or more (Group 4, 28 cases). RESULTS: On average, the alignment of the tibial implant was 0.2±1.4°, 0.1±1.3°, 0.1±1.6°, and 0.3±1.7° varus, and the tibiofemoral alignment was 5.2±1.9degrees, 4.7±1.9°, 4.9±1.9°, and 5.1±2.0° valgus for Groups 1, 2, 3, and 4, respectively, in the preoperative stage, indicating no difference between the groups (p>0.05). With respect to the accuracy of the tibial implant alignment, 98.1%, 97.6%, 87.5%, and 86.7% of Groups 1, 2, 3, and 4, respectively, had 0±3° varus angulation, demonstrating a reduced level of accuracy in Groups 3 and 4 (p<0.0001). There was no difference in terms of tibiofemoral alignment, with 83.9%, 82.9%, 85.4%, and 86.7% of each group, respectively, showing 6±3° valgus angulation (p>0.05). CONCLUSION: Satisfactory component alignment was achieved in minimally invasive surgery in total knee arthroplasty, regardless of the degree of varus deformity.

Radiologic Outcomes According to Varus Deformity in Minimally Invasive Surgery Total Knee Arthroplasty

PURPOSE: To identify the accuracy of postoperative implant alignment in minimally invasive surgery total knee arthroplasty (MIS-TKA), based on the degree of varus deformity. MATERIALS AND METHODS: The research examined 627 cases of MIS-TKA from November 2005 to December 2007. The cases were categorized according to the preoperative degree of varus deformity in the knee joint in order to compare the postoperative alignment of the implant: less than 5degrees varus (Group 1, 351 cases), 5degrees to less than 10degrees varus (Group 2, 189 cases), 10degrees to less than 15degrees varus (Group 3, 59 cases), and 15degrees varus or more (Group 4, 28 cases). RESULTS: On average, the alignment of the tibial implant was 0.2+/-1.4degrees, 0.1+/-1.3degrees, 0.1+/-1.6degrees, and 0.3+/-1.7degrees varus, and the tibiofemoral alignment was 5.2+/-1.9degrees, 4.7+/-1.9degrees, 4.9+/-1.9degrees, and 5.1+/-2.0degrees valgus for Groups 1, 2, 3, and 4, respectively, in the preoperative stage, indicating no difference between the groups (p>0.05). With respect to the accuracy of the tibial implant alignment, 98.1%, 97.6%, 87.5%, and 86.7% of Groups 1, 2, 3, and 4, respectively, had 0+/-3degrees varus angulation, demonstrating a reduced level of accuracy in Groups 3 and 4 (p0.05). CONCLUSION: Satisfactory component alignment was achieved in minimally invasive surgery in total knee arthroplasty, regardless of the degree of varus deformity.

Low femoral antetorsion as a risk factor for bony impingement after bipolar hemiarthroplasty.

INTRODUCTION: Reports of dislocation after bipolar hemiarthroplasty (BHA) abound in literature, and several studies have mentioned the factors that are associated with an increased risk of dislocation. However, there is no report detailing the pattern of impingement in BHA and how femoral antetorsion can affect the range of motion (ROM) after BHA. PURPOSE: The purpose of this study was to evaluate the pattern of impingement in BHA and whether femoral antetorsion affects the ROM after BHA using three-dimensional (3D) dynamic motion analysis. METHODS: Using the computed tomography (CT) data of 60 patients (60 hips), including 31 men and 29 women who underwent BHA for the treatment of idiopathic osteonecrosis (ION) of the femoral head, we calculated the antetorsion of the femoral neck, ROM of flexion (Flex), internal rotation (Int-R), and external rotation (Ext-R) using a CT-based 3D simulation software. We evaluated the pattern of impingement and the relationship between femoral antetorsion and ROM in BHA. As for the implant position in the 3D simulation software, the anteversion of the femoral implant was set to be the same as the natural antetorsion of the femoral neck and neck length was set to be the standard neck in all cases. RESULTS: This study revealed the mechanism of impingement in BHA: (1) bone to bone impingement and (2) implant to bone impingement. We found a significant decrease in the ROM of Flex and Int-R inversely proportional to the femoral antetorsion. In patients with lower femoral antetorsion, the ROM of Flex and Int-R decreased due to bony impingement (the anterior great trochanteric region of the femur impinges on the anteroinferior edge of the anteroinferior iliac spine). Whereas, high anteversion of the femoral implant may decrease the ROM of Ext-R; however, our results also showed that even the lowest ROM of Ext-R with 10° hip extension was over 40°. CONCLUSIONS: We demonstrated that lower femoral antetorsion substantially affects the ROM of Flex and Int-R due to bony impingement. For these patients, there should be consideration given to retaining femoral "anterior offset" in BHA.

The Impact of Wear and Lift-Off on Coronal Plane Alignment in TKA and Implications to Future Constrained Revision: A Retrieval Study.

Current discussion exists whether to position a total knee arthroplasty (TKA) in slight undercorrection in varus osteoarthritis. The goal of this study was to analyse the effect of wear and lateral lift-off in primary TKA on coronal plane alignment and the implication to future constrained revision TKA. Seventy-six retrieved tibial inserts were analysed for the ratio of wear (RW), lateral lift-off and implications for future constrained revision surgery according to the coronal plane alignment. The RW significantly affects the coronal plane alignment in TKA. Progressive wear and lateral lift-off were seen with progressive varus alignment. However, there was no difference in constrained revision between mild varus and moderate varus aligned TKAs.

Low femoral antetorsion and total hip arthroplasty: a risk factor.

PURPOSE: The purpose of this study was to evaluate whether femoral antetorsion affects the range of motion (ROM) following total hip arthroplasty (THA) using 3D dynamic analysis. METHODS: Using 3D computed tomography (CT) data of 71 patients (71 hips) who underwent THA, we calculated antetorsion of the femoral neck, flexion range of motion (Flex ROM), internal rotation (Int-R) and external rotation (Ext-R). Evaluation of the relationship between antetorsion, ROM and the impingement site was performed. As for implant position, anteversion of the femoral implant was set to be the same as natural antetorsion of the femoral neck, and the acetabular component was set 45° of total anteversion in all cases. RESULTS: We found a significant decrease in Flex ROM and Int-R inversely proportional to femoral antetorsion. In patients with lower antetorsion, Flex ROM and Int-R decreased due to bony impingement (the anterior great trochanteric region of the femur impinges on the anteroinferior edge of the anteroinferior iliac spine). However, in Ext-R, there was no relationship between ROM and femoral antetorsion. CONCLUSIONS: We demonstrated that lower femoral antetorsion substantially affects Flex ROM and Int-R due to bony impingement. For these patients, consideration must be given to retaining femoral anterior offset in THA.

Effect of opening-wedge high tibial osteotomy on the three-dimensional kinematics of the knee.

Although it is clear that opening-wedge high tibial osteotomy (HTO) changes alignment in the coronal plane, which is its objective, it is not clear how this procedure affects knee kinematics throughout the range of joint movement and in other planes. Our research question was: how does opening-wedge HTO change three-dimensional tibiofemoral and patellofemoral kinematics in loaded flexion in patients with varus deformity?Three-dimensional kinematics were assessed over 0° to 60° of loaded flexion using an MRI method before and after opening-wedge HTO in a cohort of 13 men (14 knees). Results obtained from an iterative statistical model found that at six and 12 months after operation, opening-wedge HTO caused increased anterior translation of the tibia (mean 2.6 mm, p < 0.001), decreased proximal translation of the patella (mean -2.2 mm, p < 0.001), decreased patellar spin (mean -1.4°, p < 0.05), increased patellar tilt (mean 2.2°, p < 0.05) and changed three other parameters. The mean Western Ontario and McMaster Universities Arthritis Index improved significantly (p < 0.001) from 49.6 (standard deviation (sd) 16.4) pre-operatively to a mean of 28.2 (sd 16.6) at six months and a mean of 22.5 (sd 14.4) at 12 months. The three-dimensional kinematic changes found may be important in explaining inconsistency in clinical outcomes, and suggest that measures in addition to coronal plane alignment should be considered.

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.

Anteversión pélvica como causa de dolor lumbar, síndrome patelofemoral y dolores del crecimiento / Pelvic anteversion as cause of back pain, patellofemoral syndrome and growing pains

Introducción: el dolor lumbar, el síndrome patelofemoral y los "dolores del crecimiento" son cada vez más frecuentes en niños y adolescentes, tanto en incidencia como en precocidad de aparición. En la mayoría de los casos su etiología se desconoce. Objetivo: el objetivo de esta investigación fue explorar la asociación de estas tres entidades con la anteversión pélvica. Métodos: se realizó un estudio transversal, con análisis de casos y controles, en un grupo de 30 niños con edades entre 6 y 17 años que hubieran consultado por dolor lumbar, "dolores de crecimiento" o dolor en las rodillas (casos), y otro grupo conformado por otros 30 menores sin antecedentes de dolor en dichas regiones (controles). Para la medición de la posición de la pelvis y otras variables biomecánicas se desarrolló un software que cuantifica estas medidas a partir de marcas reflectivas ubicadas sobre puntos anatómicos específicos en cada niño. Otrasmediciones fueron obtenidas a través de pruebas semiológicas y entrevistas a los menores y sus padres. Resultados: se encontró que los menores con dolor presentaronmayor anteversión de la pelvis comparados con aquellos sin dolor (medias de 13,3 y 5,4 grados, p < 0,001). Igualmente, tenían menor fuerza en los músculos extensores de columna lumbar, abdominales, psoas y diafragma. Encontramos, además, que el psoas es el músculo con mayor responsabilidad en la anteversión de la pelvis en los niños del grupo sintomático. En un menor con dolor lumbar, síndrome patelofemoral o “dolores del crecimiento” fue 4,2 veces más frecuente la presencia de fuerza deficiente o regular de los músculos extensores de columna que en los menores sin dolor. Igualmente, tuvieron casi 18 veces la probabilidad de tener un ángulo pélvico mayor de 10 grados comparado con aquellos menores sin dolor. Conclusión: los niños y adolescentes que sufren dolor lumbar, síndrome patelofemoral y “dolores de crecimiento” presentan mayor anteversión de la pelvis y menor fuerza muscular, principalmente en los extensores de columna toracolumbar, abdominales, diafragma y psoas. El estudio encontró que el músculo psoas es el que tiene mayor responsabilidad en el desarrollo de anteversión de la pelvis. La anteversión de la pelvis se asocia con dolor lumbar, síndrome patelofemoral y “dolores de crecimiento” (AU)

Introduction: Back pain, patellofemoral syndrome and "growing pains" are increasingly common in children and adolescents, both with incidence and precocity of appearance. In most cases their etiology is unknown. Objective: The objective of this research was to explore the possible association of these three entities with pelvic anteversion. Methods: This is a cross-sectional study with case-control analysis, comprising a group of 30 symptomatic children aged between 6 and 17 years (cases) who had consulted for low back pain, "growing pains" or sore knees, and a control group of 30 children with no history of pain in these areas (controls). To measure the position of the pelvis and other biomechanical variables a software programme was developed that quantifies these measurements from reflective markings located on specific anatomical landmarks of each child. Other measurements were obtained through semiological tests and interviews with children and their parents. Results: Children and adolescents with pain had more pelvic anteversion compared with controls (mean 13.3 and 5.4 degrees, p < 0.001). They also had less strength in muscles: Lumbar extensor, abdominals, psoas and diaphragm. We found that psoas is the muscle most responsible for pelvis anteversion in symptomatic group. Compared with children without pain, those with back pain, patellofemoral syndrome or "growing pains" have 4.2 times more frequent poor or regular strength in the column extensor muscles. They also have nearly 18 times as likely to have a pelvic angle greater than 10 degrees compared with no pain children. Conclusions: Children and adolescents who suffer from back pain, patellofemoral syndrome and "growing pains" have increased pelvic anteversion and lower muscle strength, mainly in the thoracolumbar spine extensors, abdominals, diaphragmand psoas. The study found that the psoas muscle is most responsible for the development of pelvis anteversion. Pelvicanteversion is associated with low back pain, patellofemoral pain syndrome and "growing pains"(AU)

Transepicondylar axes for femoral component rotation might produce flexion asymmetry during total knee arthroplasty in knees with proximal tibia vara.

BACKGROUND: Adequate rotation of the femoral component in total knee arthroplasty is mandatory for prevention of numerous adverse sequelae. Therefore, we investigate whether there is the distal femoral deformity in knees with tibia vara. The purpose of this study was to evaluate the reliability of the transepicondylar axis as a rotational landmark in knees with tibia vara. METHODS: We retrospectively reviewed and selected 101 osteoarthritic knees with proximal tibia vara and 150 osteoarthritic knees without tibia vara for inclusion in this study. The transepicondylar axis (TEA), anteroposterior (AP) axis and posterior condylar (PC) line were measured using the axial image from magnetic resonance imaging axial images. We compared the external rotation angle of the TEA relative to the PC line between groups in order to investigate the presence of distal femoral anatomical adaptation in the tibia vara group. RESULTS: The TEA in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 6.0º of external rotation in the non-tibia vara group. The line perpendicular to the AP axis in the tibia vara group had 6.1º of external rotation relative to the PC line, which was not significantly different from the 5.4º of external rotation in the non-tibia vara group. Distal femoral geometry was unaffected by the tibia vara deformity. CONCLUSIONS: The use of transepicondylar axes in determining femoral rotation may produce flexion asymmetry in knees with tibia vara. LEVEL OF EVIDENCE: Level III.

Slight undercorrection following total knee arthroplasty results in superior clinical outcomes in varus knees.

PURPOSE: Restoration of correct alignment is one of the main objectives of total knee arthroplasty (TKA). However, the influence of residual malalignment on clinical and functional outcomes is currently uncertain. This study was therefore undertaken to ascertain its influence in patients undergoing TKA for varus osteoarthritis of the knee. METHODS: A cohort of 132 consecutive patients (143 knees) with pre-operative varus alignment was evaluated with a mean follow-up period of 7.2 years. Based upon the post-operative alignment, patients were stratified into three groups: neutral, mild varus, and severe varus. These groups were compared with respect to clinical and functional outcomes. RESULTS: All patients had post-operative improvements in Knee Society Score (KSS). Knees that were left in mild varus scored significantly better for the KSS and the Western Ontario and McMaster Universities Arthritis Index, compared with knees that were corrected to neutral and knees that were left in severe varus exceeding 6°. No revisions occurred in any of the groups at midterm follow-up. CONCLUSION: The results of this study contradict the conventional assumption that correction to neutral mechanical alignment leads to the best outcome following TKA. Patients with pre-operative varus had better clinical and functional outcome scores if the alignment was left in mild varus, as compared with patients with an alignment correction to neutral. LEVEL OF EVIDENCE: Therapeutic study, Level III.

Coronal alignment is a predictor of the rotational geometry of the distal femur in the osteo-arthritic knee.

PURPOSE: There is a lot of inter-individual variation in the rotational anatomy of the distal femur. This study was set up to define the rotational anatomy of the distal femur in the osteo-arthritic knee and to investigate its relationship with the overall coronal alignment and gender. METHODS: CT-scans of 231 patients with end-stage knee osteo-arthritis prior to TKA surgery were obtained. This represents the biggest series published on rational geometry of the distal femur in literature so far. RESULTS: The posterior condylar line (PCL) was on average 1.6° (SD 1.9) internally rotated relative to the surgical transepicondylar axis (sTEA). The perpendicular to trochlear anteroposterior axis (⊥TRAx) was on average 4.8° (SD 3.3°) externally rotated relative to the sTEA. The relationship between the PCL and the sTEA was statistically different in the different coronal alignment groups (p < 0.001): 1.0° (SD 1.8°) in varus knees, 2.1° (SD 1.8°) in neutral knees and 2.6° (SD 1.8°) in valgus knees. The same was true for the ⊥TRAx in these 3 groups (p < 0.02).There was a clear linear relationship between the overall coronal alignment and the rotational geometry of the distal femur. For every 1° in coronal alignment increment from varus to valgus, there is a 0.1° increment in posterior condylar angle (PCL vs sTEA). CONCLUSION: The PCL was on average 1.6° internally rotated relative to the sTEA in the osteo-arthritic knee. The relationship between the PCL and the sTEA was statistically different in the different coronal alignment groups. LEVEL OF EVIDENCE: III.

Rotational limb alignment changes following total knee arthroplasty.

PURPOSE: The aim of the present study was to assess the changes in rotational alignment introduced by total knee arthroplasty (TKA) and the reproducibility of pre- and postoperative CT measurements of rotational limb alignment. METHODS: For this purpose we analyzed data from 196 consecutive cruciate-retaining, fixed bearing Columbus TKA procedures. Both pre- and postoperative scans torsion difference CT scans were available for measurements in 89 cases. Using these CT scans the neck-malleolar angle (NMA), the femoral posterior condylar angle (fPCA), the tibial posterior condylar axis (tPCA) and the tibial torsion angle (TTA) were independently assessed by three raters. CT scans were re-evaluated 8 weeks later by the most experienced rater for assessment of intraobserver agreement. RESULTS: Measurements of all angles were prone to high standard deviations reflecting interindividual variability. Mean fPCA changed from 1.3° to 2.7° internal rotation preoperatively to 0.1°-1.9° internal rotation postoperatively. Based on a relative external rotation of the tibial base plate as compared to the preoperative situation, we found a relative internal rotation of the postoperative NMA and tibial torsion of 3°-5.4° and 6°-7.5°, respectively. Intra- and interobserver agreement was strong for all angles assessed (ICCs 0.7-1.0) except for fPCA (ICC 0.2-0.6). However, mean absolute measurement differences for fPCA were clinically acceptable (1.2°-2.6°). CONCLUSIONS: Reproducibility of CT rotational limb alignment measurements was found to be clinically acceptable. Rotational alignment of the femoral and even more so of the tibial component will ultimately affect the rotational alignment of the entire limb-at least when fixed bearings are used. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Does the severity of preoperative varus deformity influence postoperative alignment in both conventional and computer-assisted total knee arthroplasty?

PURPOSE: The postoperative alignment was compared according to the severity of preoperative varus deformity in computer-assisted and conventional total knee arthroplasty (CAS-TKA). METHODS: The study reviewed 127 consecutive CAS-TKA and 236 conventional TKA, retrospectively. In CAS-TKA, 77 knees with a varus deformity ≤15.0° were classified in group CAS-A and 50 knees with a varus deformity >15.0° were classified in group CAS-B. In conventional groups, 204 knees with a varus deformity ≤15.0 were classified in group Conventional-A and 32 knees with a varus deformity >15.0° were classified in group Conventional-B. The postoperative mechanical axis (MA) was compared among groups CAS-A, CAS-B, Conventional-A and Conventional-B. RESULTS: The average postoperative MA was 0.7° varus in group CAS-A, 2.8° varus in group CAS-B, 1.1° varus in group Conventional-A and 3.2° varus in group Conventional-B (p < 0.001). The postoperative MA was within 3° in 81.8, 62.0, 58.8 and 37.5 % of group CAS-A, CAS-B, Conventional-A and Conventional-B, respectively. CONCLUSIONS: The severity of preoperative varus deformity influences postoperative alignment despite using CAS. More careful correction of the alignment is required, especially in TKA performed on patients with a greater varus deformity. LEVEL OF EVIDENCE: III.