Gait deviations and compensations in pediatric patients with increased femoral torsion

Greater hip internal rotation range of motion is associated with increased dynamic knee valgus during jump landing, both before and after fatigue

PURPOSE

The aim of this study was to analyse sex-specific differences contributing to dynamic valgus in competitive soccer players before and after a standardised fatiguing protocol.

METHODS

Thirty-nine healthy female and male competitive soccer players (19 females and 20 males) were recruited for the purpose of this study. Bilateral medial knee displacement (MKD) was assessed during drop jump landings using a three-dimensional motion capture system before and after a standardised fatiguing protocol. In addition, all soccer players underwent clinical examinations, including rotational hip range of motion (ROM), isokinetic strength testing and magnetic resonance imaging (MRI) of the hip and knee. Sex-specific and fatigue-dependent differences were reported, and the influence of demographic, clinical and radiographic factors on MKD was analysed via multiple linear regression models.

RESULTS

Compared with male soccer players, female soccer players demonstrated a tendency towards increased MKD during drop jump landings before (p = 0.09) and after the fatiguing protocol (p = 0.04). Sex-specific differences included increased hip internal rotation (IR) ROM, decreased hip external rotation (ER) strength and increased femoral torsion in females (all p < 0.002). According to the multiple linear regression models (stepwise method), increased hip IR ROM (90° of flexion) and the non-dominant leg remained the sole independent predictors of increased MKD during drop jump landings before (p < 0.01 and p = 0.02, respectively) and after fatigue (p < 0.01 and p < 0.01, respectively). An increase in hip IR ROM in females was linearly related to MKD after fatigue (R2 = 0.25; p < 0.01).

CONCLUSION

Female soccer players exhibited increased dynamic valgus before and after fatigue, which is likely attributed to joint mobility, as well as muscular and anatomical differences, such as increased hip IR ROM, reduced hip ER strength and increased femoral torsion. In particular, females with increased hip IR ROM were more susceptible to effects of fatigue on MKD, which may increase their risk for anterior cruciate ligament injury.

LEVEL OF EVIDENCE

Level III.

Femoral bone growth predictions based on personalized multi-scale simulations: validation and sensitivity analysis of a mechanobiological model

Musculoskeletal function is pivotal to long-term health. However, various patient groups develop torsional deformities, leading to clinical, functional problems. Understanding the interplay between movement pattern, bone loading and growth is crucial for improving the functional mobility of these patients and preserving long-term health. Multi-scale simulations in combination with a mechanobiological bone growth model have been used to estimate bone loads and predict femoral growth trends based on cross-sectional data. The lack of longitudinal data in the previous studies hindered refinements of the mechanobiological model and validation of subject-specific growth predictions, thereby limiting clinical applications. This study aimed to validate the growth predictions using magnetic resonance images and motion capture data-collected longitudinally-from ten growing children. Additionally, a sensitivity analysis was conducted to refine model parameters. A linear regression model based on physical activity information, anthropometric data and predictions from the refined mechanobiological model explained 70% of femoral anteversion development. Notably, the direction of femoral development was accurately predicted in 18 out of 20 femurs, suggesting that growth predictions could help to revolutionize treatment strategies for torsional deformities.

Distal femoral osteotomy for the treatment of chronic patellofemoral instability improves gait patterns

PURPOSE

The purpose of this study was to evaluate pre- to postoperative changes in clinical and functional outcomes as well as gait patterns in patients who underwent surgery for chronic patellofemoral instability (PFI).

METHODS

Patients who underwent surgery for the treatment of recurrent PFI according to an individual risk factor analysis were included. Pre- and minimum 12 months postoperatively, patient-reported outcome measures (PROM; Kujala score, Lysholm score, Tegner Activity Scale [TAS] and Visual Analog Scale for pain) as well as gait (dynamic Q-angle) and function (dynamic valgus and dynamic Trendelenburg during single-leg squat) via videography were evaluated. Subgroup analysis was performed based on whether or not patients underwent concomitant distal femoral osteotomy (DFO) due to coronal and/or torsional malalignment.

RESULTS

Twenty-three patients were included (follow-up: 12.5 [12.1-13.0] months), of which 60.9% patients underwent a concomitant DFO. All PROM improved significantly (p < 0.05). Overall, dynamic Q-angle (p = 0.016) and dynamic valgus (p = 0.041) were observed significantly less frequently postoperatively when to compared to preoperatively. Subgroup analysis showed that only the group that underwent DFO had a significant improvement of dynamic Q-angle (p = 0.041). Dynamic Trendelenburg did not improve (p > 0.05). Regression analysis showed that the presence of a postoperative dynamic Q-angle was associated with a worse postoperative Kujala score (p = 0.042) and TAS (p = 0.049).

CONCLUSION

Patient-individualized surgery for PFI improved gait patterns and functional testing, especially in patients who also underwent DFO. The presence of dynamic Q-angle postoperatively was associated with significantly worse functional outcome and sporting ability.

LEVEL OF EVIDENCE

Level III.

Effect of femoral derotational osteotomy in patients with idiopathic increased femoral anteversion on joint loading and muscular demands

Purpose

This study aimed to analyse the effect of the femoral derotational osteotomy (FDRO) on joint kinematics, kinetics, joint and muscle forces, and muscle moments in patients with idiopathic increased femoral anteversion compared with typically developing children (TDC).

Methods

In this retrospective study, 17 patients (25 limbs, 13.2 ± 2.2 years, femoral anteversion = 49.0° ± 7.1°) were compared to nine TDC (9 limbs, 12.0 ± 3.0 years, femoral anteversion = 18.7° ± 4.1°). Gait analysis was performed 8.5 ± 7.2 months pre-surgery and 17.3 ± 5.5 months post-surgery. Joint angles, moments and forces as well as muscle forces and muscle contributions to joint moments were analysed using statistical parametric mapping.

Results

Significant improvements in kinematics (hip rotation, foot progression, knee and hip flexion) were observed pre- to post-FDRO. Joint forces remained unaltered after surgery and did not differ from TDC. Gluteus minimus and deep external rotators muscle forces decreased in mid-stance, while adductor muscle forces increased during stance post-op compared to pre-op. Due to an improved knee extension postoperatively, the rectus femoris muscle force decreased to normal values during mid- and terminal stance. Postoperatively, only the deep external rotator muscle forces differed from TDC.

Conclusions

This study showed that FDRO can restore muscle forces and muscle contributions to joint moments in addition to normal gait kinematics, while joint contact forces remain within normative ranges. This knowledge might also apply to other conditions in which pathological femoral anteversion is present.

A new method for assessing tibial torsion using computerized tomography in a pediatric population

Purpose

Tibial torsion disorders may lead to abnormal gait, frequently leading to a consultation with a pediatric orthopedic surgeon. The present study evaluated an alternative method for assessing tibial torsion on computerized tomography (CT) images that considers the tibial distal axis to be equivalent to the geometric axis of the tibiotalar joint.

Methods

One hundred CT scans were reviewed retrospectively, and four measurements were taken: proximal transtibial angle (PTTA), posterior margin tibial plateau angle (PMTPA), intermalleolar angle (IMA), and talar angle (TA). The tibial torsion angle was then calculated using these different angles.

Results

The patient cohort comprised 38 girls and 62 boys, with a mean age of 12 ± 4.4 years. Median PTTA and PMTPA were -8.4° ± 14.7° and -8.8° ± 14.2°, respectively, with no statistically significant difference. Mean IMA and TA were 23° ± 16.2° and 17.2° ± 16.9°, respectively, with a statistically significant difference. Mean total measurement time per patient was 6'44", with means of 2'24" for PTTA, 36" for PMTPA, 2'14" for IMA, and 1'12" for TA.

Conclusion

Tibial torsion values may differ significantly depending on the axis chosen to define tibial orientation. At the level of the proximal tibia, the choice of PTTA or PMTPA had little influence on the calculation of the tibial torsion angle. There was a significant difference of 5.8° when measuring the distal tibia. Measuring the PMTPA and TA is probably more suited for use in clinical practice because their tracing is simple and faster.

Influence of femoral anteversion angle and neck-shaft angle on muscle forces and joint loading during walking

Femoral deformities, e.g. increased or decreased femoral anteversion (AVA) and neck-shaft angle (NSA), can lead to pathological gait patterns, altered joint loads, and degenerative joint diseases. The mechanism how femoral geometry influences muscle forces and joint load during walking is still not fully understood. The objective of our study was to investigate the influence of femoral AVA and NSA on muscle forces and joint loads during walking. We conducted a comprehensive musculoskeletal modelling study based on three-dimensional motion capture data of a healthy person with a typical gait pattern. We created 25 musculoskeletal models with a variety of NSA (93°-153°) and AVA (-12°-48°). For each model we calculated moment arms, muscle forces, muscle moments, co-contraction indices and joint loads using OpenSim. Multiple regression analyses were used to predict muscle activations, muscle moments, co-contraction indices, and joint contact forces based on the femoral geometry. We found a significant increase in co-contraction of hip and knee joint spanning muscles in models with increasing AVA and NSA, which led to a substantial increase in hip and knee joint contact forces. Decreased AVA and NSA had a minor impact on muscle and joint contact forces. Large AVA lead to increases in both knee and hip contact forces. Large NSA (153°) combined with large AVA (48°) led to increases in hip joint contact forces by five times body weight. Low NSA (108° and 93°) combined with large AVA (48°) led to two-fold increases in the second peak of the knee contact forces. Increased joint contact forces in models with increased AVA and NSA were linked to changes in hip muscle moment arms and compensatory increases in hip and knee muscle forces. Knowing the influence of femoral geometry on muscle forces and joint loads can help clinicians to improve treatment strategies in patients with femoral deformities.

Excessive Femoral Anteversion Leading to Symptomatic Posterior Femoroacetabular Impingement, Cam Deformity of the Posterior Femoral Head-Neck Junction, and Anterior Hip Instability in a Dancer: A Case Report

CASE

An adolescent female dancer with excessive femoral anteversion presented with posterior and anterior hip pain aggravated by poses that required extension and external rotation. Imaging revealed an atypical cam deformity of the posterior head-neck junction. During surgery, the posterior head-neck junction was observed to impinge on the posterior acetabulum with anterior subluxation of the hip. After a derotational femoral osteotomy, the patient experienced resolution of her symptoms.

CONCLUSION

Excessive femoral anteversion can lead to reactive cam deformity, posterior intra-articular impingement, and anterior hip instability in patients who require repetitive hip extension and external rotation, such as ballet dancers.

Posterior Hip Impingement at Maximal Hip Extension in Female Patients With Increased Femoral Version or Increased McKibbin Index and Its Effect on Sports Performance

Background

The location of posterior hip impingement at maximal extension in patients with posterior femoroacetabular impingement (FAI) is unclear.

Purpose

To investigate the frequency and area of impingement at maximal hip extension and at 10° and 20° of extension in female patients with increased femoral version (FV) and posterior hip pain.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Osseous patient-specific 3-dimensional (3D) models were generated of 50 hips (37 female patients, 3D computed tomography) with a positive posterior impingement test and increased FV (defined as >35°). The McKibbin index (combined version) was calculated as the sum of FV and acetabular version (AV). Subgroups of patients with an increased McKibbin index >70° (24 hips) and FV >50° (20 hips) were analyzed. A control group of female participants (10 hips) had normal FV, normal AV, and no valgus deformity (neck-shaft angle, <139°). Validated 3D collision detection software was used for simulation of osseous impingement-free hip extension (no rotation).

Results

The mean impingement-free maximal hip extension was significantly lower in patients with FV >35° compared with the control group (15° ± 15° vs 55° ± 19°; P < .001). At maximal hip extension, 78% of patients with FV >35° had osseous posterior extra-articular ischiofemoral hip impingement. At 20° of extension, the frequency of posterior extra-articular ischiofemoral impingement was significantly higher for patients with a McKibbin index >70° (83%) and for patients with FV >35° (76%) than for controls (0%) (P < .001 for both). There was a significant correlation between maximal extension (no rotation) and FV (r = 0.46; P < .001) as well as between impingement area at 20° of extension (external rotation [ER], 0°) and McKibbin index (0.61; P < .001). Impingement area at 20° of extension (ER, 0°) was significantly larger for patients with McKibbin index >70° versus <70° (251 vs 44 mm²; P = .001).

Conclusion

The limited hip extension found in our study could theoretically affect the performance of sports activities such as running, ballet dancing, or lunges. Therefore, although not examined directly in this study, these activities are not advisable for these patients. Preoperative evaluation of FV and the McKibbin index is important in female patients with posterior hip pain before hip preservation surgery (eg, hip arthroscopy).

The effect of functional calibration methods on gait kinematics in adolescents with idiopathic rotational deformity of the femur

BACKGROUND

Due to anatomical deviations, assumptions of the conventional calibration method for gait analysis may be violated in individuals with rotational deformities of the femur. Functional calibration methods were compared with conventional methods in this group for 1) localization of the hip joint center and orientation of the knee axis, and 2) gait kinematics.

METHODS

Twenty-four adolescents with idiopathic rotational deformity of the femur underwent gait analysis and a CT scan. During standing, distance between hip joint centers and knee axis orientation were compared between calibration methods, with CT serving as reference for hip joint center estimation. Gait kinematics were compared using statistical parametric mapping.

FINDINGS

The conventional calibration method estimated the hip joint center closer to the CT reference (4±12 mm more lateral) than the functional calibration method (26 ± 20 mm more lateral). Orientation of the knee joint axis was 2.6° less internal in the functional calibration method. During gait, statistical parametric mapping revealed significantly more hip flexion, less external hip rotation during the swing phase, less knee varus-valgus motion, and larger knee flexion angles when applying the functional method.

INTERPRETATION

Functional calibration methods were less accurate in determining the hip joint center location than the conventional calibration method and resulted in a knee joint axis that was less internally rotated. Importantly, there was less knee joint angle crosstalk during gait when using the functional method. Although differences between methods on gait kinematics were within clinically acceptable limits for the sagittal plane, relatively larger differences on transversal hip kinematics may hold clinical importance.

Limited External Rotation and Hip Extension Due to Posterior Extra-articular Ischiofemoral Hip Impingement in Female Patients With Increased Femoral Anteversion: Implications for Sports, Sexual, and Daily Activities

BACKGROUND

Posterior femoroacetabular impingement (FAI) is poorly understood. Patients with increased femoral anteversion (FV) exhibit posterior hip pain.

PURPOSE

To correlate hip impingement area with FV and with combined version and to investigate frequency of limited external rotation (ER) and hip extension (<40°, <20°, and <0°) due to posterior extra-articular ischiofemoral impingement.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Osseous patient-specific three-dimensional (3D) models based on 3D computed tomography scans were generated of 37 female patients (50 hips) with positive posterior impingement test (100%) and increased FV >35° (Murphy method). Surgery was performed in 50% of patients (mean age, 30 years; 100% female). FV and acetabular version (AV) were added to calculate combined version. Subgroups of patients (24 hips) with increased combined version >70° and patients (9 valgus hips) with increased combined version >50° were analyzed. The control group (20 hips) had normal FV, normal AV, and no valgus. Bone segmentation was performed to generate 3D models of every patient. Validated 3D collision detection software was used for simulation of impingement-free hip motion (equidistant method). Impingement area was evaluated in combined 20° of ER and 20° of extension.

RESULTS

Posterior extra-articular ischiofemoral impingement occurred between the ischium and the lesser trochanter in 92% of patients with FV >35° in combined 20° of ER and 20° of extension. Impingement area in combined 20° of ER and 20° of extension was larger with increasing FV and with higher combined version; correlation was significant (P < .001, r = 0.57, and r = 0.65). Impingement area was significantly (P = .001) larger (681 vs 296 mm2) for patients with combined version >70° (vs <70°, respectively) in combined 20° of ER and 20° of extension. All symptomatic patients with increased FV >35° (100%) had limited ER <40°, and most (88%) had limited extension <40°. The frequency of posterior intra- and extra-articular hip impingement of symptomatic patients (100% and 88%, respectively) was significantly (P < .001) higher compared with the control group (10% and 10%, respectively). The frequency of patients with increased FV >35° with limited extension <20° (70%) and patients with limited ER <20° (54%) was significantly (P < .001) higher compared with the control group (0% and 0%, respectively). The frequency of completely limited extension <0° (no extension) and ER <0° (no ER in extension) was significantly (P < .001) higher for valgus hips (44%) with combined version >50° compared with patients with FV >35° (0%).

CONCLUSION

All patients with increased FV >35° had limited ER <40°, and most of them had limited extension <20° due to posterior intra- or extra-articular hip impingement. This is important for patient counselling, for physical therapy, and for planning of hip-preservation surgery (eg, hip arthroscopy). This finding has implications and could limit daily activities (long-stride walking), sexual activity, ballet dancing, and sports (eg, yoga or skiing), although not studied directly. Good correlation between impingement area and combined version supports evaluation of combined version in female patients with positive posterior impingement test or posterior hip pain.

Patellofemoral joint load and knee abduction/adduction moment are sensitive to variations in femoral version and individual muscle forces

Torsional profiles of the lower limbs, such as femoral anteversion, can dictate gait and mobility, joint biomechanics and pain, and functional impairment. It currently remains unclear how the interactions between femoral anteversion, kinematics, and muscle activity patterns contribute to joint biomechanics and thus conditions such as knee pain. This study presents a computational modeling approach to investigating the interactions between femoral anteversion, muscle forces, and knee joint loads. We employed an optimal control approach to produce actuator and muscle-driven simulations of the stance phase of gait for femoral anteversion angles ranging from -8° (retroversion) to 52° (anteversion) with a typically developing baseline of 12° of anteversion and implemented a Monte Carlo analysis for variations in lower limb muscle forces. While total patellofemoral joint load decreased with increasing femoral anteversion, patellofemoral joint load alignment worsened, and knee abduction/adduction magnitude increased with both positive and negative changes in femoral anteversion (p < 0.001). The rectus femoris muscle was found to greatly influence patellofemoral joint loads across all femoral anteversion alignments (R > 0.8, p < 0.001), and the medial gastrocnemius was found to greatly influence knee abduction/adduction moments for the extreme version cases (R > 0.74, p < 0.001). Along with the vastus lateralis, which decreased with increasing femoral anteversion (R = 0.89, p < 0.001), these muscles are prime candidates for future experimental and clinical efforts to address joint pain in individuals with extreme femoral version. These findings, along with future modeling efforts, could help clinicians better design treatment strategies for knee joint pain in populations with extreme femoral anteversion or retroversion.

The functional role of hip muscles during gait in patients with increased femoral anteversion

BACKGROUND

Femoral anteversion affects the lever arm and moment-generating capacity of the hip abductors, while an increased hip internal rotation during walking was proposed to be a compensatory mechanism to restore the abductive lever arm. Children with isolated increased femoral anteversion, however, do not always present a deficit in the net hip abduction moment during gait, suggesting that a more comprehensive understanding of the effect of morphology and motion on muscle forces and moments is needed to aid clinical decision making.

RESEARCH QUESTION

Are muscle contributions to hip joint moments and muscle forces altered in patients with increased femoral anteversion and internally rotated gait pattern compared to a control group of typically developing children? And how would the functional role of the muscle be altered if the patients walked straight?

METHODS

This follow-up study compared patients with increased femoral anteversion (n = 42, 12.8 ± 1.9 years, femoral anteversion: 39.6 ± 6.9°) to controls (n = 9, 12.0 ± 3.0 years, femoral anteversion: 18.7 ± 4.1°). Muscle forces and moment contributions were calculated using personalized musculoskeletal models. Additionally, a hypothetical scenario, in which the gait of the controls was modelled with an anteverted femoral morphology, was used to understand what would happen if the patients walked straight.

RESULTS

Gluteus medius abductive contribution was lower in patients compared to controls, despite a comparable net abduction moment around the hip. Patients presented lower muscle forces. However, if modelled to walk straight, they would require higher forces as well as a larger co-contraction of both hip internal and external rotators in the transversal plane.

SIGNIFICANCE

This study suggests that patients with increased femoral anteversion walking with an internally rotated gait pattern present lower muscle forces, but when modelled to walk straight muscle forces increase. The current results provide important information to better understand this condition and improve treatment recommendations in these patients.

Hawthorne Effect in Gait Analysis of Children with In-Toeing Caused by Increased Femoral Anteversion

Background

In-toeing is one of the main reasons children are applying to the orthopedics clinic. In the clinical settings, during in-toeing gait assessment parents often define that their child does not walk same at the clinic as at home, linked possibly to Hawthorne effect.

Research Question

How does the in-toeing angle differ when children are aware, versus when they are not aware of their gait inspection?

Methods

This single center, clinical, cross-sectional, observational study looked into the variation in gait pattern of twelve children with in-toeing, with and without their awareness. Two videos for each child was recorded with a smart phone, once at the clinic while aware and once by the family without awareness, and uploaded into Kinovea software for gait analysis. The angle of foot in-toeing was measured and analyzed using SPSS comparison of means and correlations.

Results

The gait pattern evaluated with the angle of in-toeing showed a significant difference between the two videos of the same child. The angle difference returned a p value of 0.000 using paired sample t test and a Cohen's d value of 1.4, representing the large significance between clinic and family recorded videos. The initial foot in-toeing angle showed a moderate positive Pearson's correlation of 0.031 when compared with the angle difference in both settings.

Significance

These results highlight the importance of including family recorded videos in gait pattern analysis without the patient's awareness. The study not only shows the significant difference found which can be explained by Hawthorne Effect but also suggests a clearer path of understanding the child's condition with the family.

Frontal plane knee moment in clinical gait analysis: A systematic review on the effect of kinematic gait changes

INTRODUCTION

The frontal plane knee moment (KAM1 and KAM2) derived from non-invasive three-dimensional gait analysis is a surrogate measure for knee joint load and of great interest in clinical and research settings. Many aspects can influence this measure either unintentionally or purposely in order to reduce the knee joint load to relieve symptoms and pain. All these aspects must be known when conducting a study or interpreting gait data for clinical decision-making.

METHODS

This systematic review was registered with PROSPERO (CRD42020187038). Pubmed and Web of Science were searched for peer-reviewed, original research articles in which unshod three-dimensional gait analysis was undertaken and KAM1 and KAM2 were included as an outcome variable. Two reviewers independently screened articles for inclusion, extracted data and performed a methodological quality assessment using Downs and Black checklist.

RESULTS

In total, 42 studies were included. Based on the independent variable investigated, these studies were divided into three groups: 1) gait modifications, 2) individual characteristics and 3) idiopathic orthopedic deformities. Among others, fast walking speeds (1) were found to increase KAM1; There were no sex-related differences (2) and genu valgum (3) reduces KAM1 and KAM2.

CONCLUSION

While consistent use of terminology and reporting of KAM is required for meta-analysis, this review indicates that gait modifications (speed, trunk lean, step width), individual characteristics (body weight, age) and idiopathic orthopedic deformities (femoral or tibial torsion, genu valgum/varum) influence KAM magnitudes during walking. These factors should be considered by researchers when designing studies (especially of longitudinal design) or by clinicians when interpreting data for surgical and therapeutic decision-making.

Increased Femoral Anteversion Does Not Lead to Increased Joint Forces During Gait in a Cohort of Adolescent Patients

Orthopedic complications were previously reported for patients with increased femoral anteversion. A more comprehensive analysis of the influence of increased femoral anteversion on joint loading in these patients is required to better understand the pathology and its clinical management. Therefore, the aim was to investigate lower-limb kinematics, joint moments and forces during gait in adolescent patients with increased, isolated femoral anteversion compared to typically developing controls. Secondly, relationships between the joint loads experienced by the patients and different morphological and kinematic features were investigated. Patients with increased femoral anteversion (n = 42, 12.8 ± 1.9 years, femoral anteversion: 39.6 ± 6.9°) were compared to typically developing controls (n = 9, 12.0 ± 3.0 years, femoral anteversion: 18.7 ± 4.1°). Hip and knee joint kinematics and kinetics were calculated using subject-specific musculoskeletal models. Differences between patients and controls in the investigated outcome variables (joint kinematics, moments, and forces) were evaluated through statistical parametric mapping with Hotelling T2 and t-tests (α = 0.05). Canonical correlation analyses (CCAs) and regression analyses were used to evaluate within the patients’ cohort the effect of different morphological and kinematic predictors on the outcome variables. Predicted compressive proximo-distal loads in both hip and knee joints were significantly reduced in patients compared to controls. A gait pattern characterized by increased knee flexion during terminal stance (KneeFlex_tSt) was significantly correlated with hip and knee forces, as well as with the resultant force exerted by the quadriceps on the patella. On the other hand, hip internal rotation and in-toeing, did not affect the loads in the joints. Based on the finding of the CCAs and linear regression analyses, patients were further divided into two subgroups based KneeFlex_tSt. Patients with excessive KneeFlex_tSt presented a significantly higher femoral anteversion than those with normal KneeFlex_tSt. Patients with excessive KneeFlex_tSt presented significantly larger quadriceps forces on the patella and a larger posteriorly-oriented shear force at the knee, compared to patients with normal KneeFlex_tSt, but both patients’ subgroups presented only limited differences in terms of joint loading compared to controls. This study showed that an altered femoral morphology does not necessarily lead to an increased risk of joint overloading, but instead patient-specific kinematics should be considered.

Minimal Out-Toeing and Good Hip Scores of Severe SCFE Patients Treated With Modified Dunn Procedure and Contralateral Prophylactic Pinning at Minimal 5-year Follow up

BACKGROUND

Slipped capital femoral epiphyses (SCFE) is associated with out-toeing of the foot and external rotation gait. But it is unknown if SCFE patients treated with the modified Dunn procedure have out-toeing at follow up.Therefore, we used instrumented gait analysis and questioned (1) do severe SCFE patients treated with a modified Dunn procedure have symmetrical foot progression angle (FPA) compared with contralateral side and compared with asymptomatic volunteers (2) what is the prevalence of out-toeing gait and what are the outcome socres at follow up.

METHODS

Gait analysis of 22 patients (22 hips) treated with an unilateral modified Dunn procedure for severe SCFE (slip angle >60 degrees, 2002 to 2011) was retrospectively evaluated. Of 38 patients with minimal 5-year follow up, 2 hips (4%) had avascular necrosis of the femoral head and were excluded for gait analysis. Twenty-two patients were available for gait analysis at follow up (mean follow up of 9±2 y). Mean age at follow up was 22±3 years. Mean preoperative slip angle was 64±8 degrees (33% unstable slips) and decreased postoperatively (slip angle of 8±4 degrees). Gait analysis was performed with computer-based instrumented walkway system (GAITRite) to measure FPA with embedded pressure sensors. Patients were compared with control group of 18 healthy asymptomatic volunteers (36 feet, mean age 29±6 y).

RESULTS

(1) Mean FPA of SCFE patients (3.6±6.4 degrees) at follow up was not significantly different compared with their contralateral side (5.6±5.5 degrees) and compared with FPA of controls (4.0±4.5 degrees). (2) Of the 22 SCFE patients, most of them (19 hips, 86%) had normal FPA (-5 to 15 degrees), 2 patients had in-toeing (FPA<-5 degrees) and 1 had out-toeing (FPA >15 degrees) and was not significantly different compared with control group. (3) Mean modified Harris hip score (mHHS) was 93±11 points, mean Hip Disability and Osteoarthritis Outcome Score (HOOS) score was 91±10 points. Three patients (14%) had mHHS <80 points and walked with normal FPA. The 2 patients with in-toeing and one patient with out-toeing had mHHS >95 points.

CONCLUSIONS

Patients with severe SCFE treated with modified Dunn procedure had mostly symmetrical FPA and good hip scores at long term follow up. This is in contrast to previous studies. Although 1 patient had out-toeing and 2 patients had in-toeing at follow up, they had good hip scores.

LEVEL OF EVIDENCE

Level III-retrospective comparative study.

Less in-toeing after femoral derotation osteotomy in adult patients with increased femoral version and posterior hip impingement compared to patients with femoral retroversion

In-toeing of the foot was associated with high femoral version (FV), while Out-toeing was associated with femoral-retroversion. Therefore, we report on (i) foot-progression-angle (FPA), (ii) prevalence of In-toeing and Out-toeing, and (iii) clinical outcome of patients treated with femoral-derotation-osteotomy (FDO). We performed a retrospective analysis involving 20 patients (20 hips) treated with unilateral FDO (2017–18). Of them, 14 patients had increased FV, 6 patients had femoral-retroversion. Follow-up time was mean 1 ± 1 years. All patients had minimal 1-year follow-up and the mean age was 29 ± 8 years. Patients with increased FV (FV > 35°) presented with positive posterior-impingement-test and mean FV was 49 ± 11° (Murphy method). Six patients with femoral-retroversion (FV < 10°) had positive anterior impingement test and mean FV of 5 ± 4°. Instrumented gait analysis was performed preoperatively and at follow-up using the Gaitrite system to measure FPA and was compared to a control group of 18 healthy asymptomatic volunteers (36 feet, mean age 29 ± 6 years). (i) Mean FPA increased significantly (P = 0.006) from preoperative 1.3 ± 7° to 4.5 ± 6° at follow-up for patients with increased FV and was not significantly different compared to the control group (4.0 ± 4.5°). (ii) In-toeing decreased from preoperatively (five patients) to follow-up (two patients) for patients with increased FV. Out-toeing decreased from preoperatively (two patients) to follow-up (no patient) for patients with femoral-retroversion. (iii) Subjective-hip-value of all patients increased significantly (P < 0.001) from preoperative 21 to 78 points at follow-up. WOMAC was 12 ± 8 points at follow-up. Patients with increased FV that underwent FDO walked with less In-toeing. FDO has the potential to reduce In-toeing and Out-toeing and to improve subjective satisfaction at follow-up.

Subject-Specific Modeling of Femoral Torsion Influences the Prediction of Hip Loading During Gait in Asymptomatic Adults

Hip osteoarthritis may be caused by increased or abnormal intra-articular forces, which are known to be related to structural articular cartilage damage. Femoral torsional deformities have previously been correlated with hip pain and labral damage, and they may contribute to the onset of hip osteoarthritis by exacerbating the effects of existing pathoanatomies, such as cam and pincer morphologies. A comprehensive understanding of the influence of femoral morphotypes on hip joint loading requires subject-specific morphometric and biomechanical data on the movement characteristics of individuals exhibiting varying degrees of femoral torsion. The aim of this study was to evaluate hip kinematics and kinetics as well as muscle and joint loads during gait in a group of adult subjects presenting a heterogeneous range of femoral torsion by means of personalized musculoskeletal models. Thirty-seven healthy volunteers underwent a 3D gait analysis at a self-selected walking speed. Femoral torsion was evaluated with low-dosage biplanar radiography. The collected motion capture data were used as input for an inverse dynamics analysis. Personalized musculoskeletal models were created by including femoral geometries that matched each subject’s radiographically measured femoral torsion. Correlations between femoral torsion and hip kinematics and kinetics, hip contact forces (HCFs), and muscle forces were analyzed. Within the investigated cohort, higher femoral antetorsion led to significantly higher anteromedial HCFs during gait (medial during loaded stance phase and anterior during swing phase). Most of the loads during gait are transmitted through the anterior/superolateral quadrant of the acetabulum. Correlations with hip kinematics and muscle forces were also observed. Femoral antetorsion, through altered kinematic strategies and different muscle activations and forces, may therefore lead to altered joint mechanics and pose a risk for articular damage. The method proposed in this study, which accounts for both morphological and kinematic characteristics, might help in identifying in a clinical setting patients who, as a consequence of altered femoral torsional alignment, present more severe functional impairments and altered joint mechanics and are therefore at a higher risk for cartilage damage and early onset of hip osteoarthritis.

Posterior Extra-articular Ischiofemoral Impingement Can Be Caused by the Lesser and Greater Trochanter in Patients With Increased Femoral Version: Dynamic 3D CT-Based Hip Impingement Simulation of a Modified FABER Test

Background:

Posterior extra-articular hip impingement has been described for valgus hips with increased femoral version (FV). These patients can present clinically with lack of external rotation (ER) and extension and with a positive posterior impingement test. But we do not know the effect of the combination of deformities, and the impingement location in early flexion is unknown.

Purpose:

To evaluate patient-specific 3-dimensional computed tomography (3D CT) scans of hips with increased FV and control hips for differences in range of motion, location and prevalence of osseous posterior intra- and extra-articular hip impingement.

Study Design:

Case series; Level of evidence, 4.

Methods:

Osseous 3D models based on segmentation of 3D CT scans were analyzed for 52 hips (38 symptomatic patients) with positive posterior impingement test and increased FV (>35°). There were 26 hips with an increased McKibbin instability index >70 (unstable hips). Patients were mainly female (96%), with an age range of 18 to 45 years. Of them, 21 hips had isolated increased FV (>35°); 22 hips had increased FV and increased acetabular version (AV; >25°); and 9 valgus hips (caput-collum-diaphyseal angle >139°) had increased FV and increased AV. The control group consisted of 20 hips with normal FV, normal AV, and no valgus (caput-collum-diaphyseal angle <139°). Validated 3D CT–based collision detection software for impingement simulation was used to calculate impingement-free range of motion and location of hip impingement. Surgical treatment was performed after the 3D CT–based impingement simulation in 27 hips (52%).

Results:

Hips with increased FV had significantly (P < .001) decreased extension and ER at 90° of flexion as compared with the control group. Posterior impingement was extra-articular (92%) in hips with increased FV. Valgus hips with increased FV and AV had combined intra- and extra-articular impingement. Posterior hip impingement occurred between the ischium and the lesser trochanter at 20° of extension and 20° of ER. Impingement was located between the ischium and the greater trochanter or intertrochanteric area at 20° of flexion and 40° of ER, with a modification of the flexion-abduction-ER (FABER) test.

Conclusion:

Posterior extra-articular ischiofemoral hip impingement can be caused by the lesser and greater trochanter or the intertrochanteric region. We recommend performing the modified FABER test during clinical examination in addition to the posterior impingement test for female patients with high FV. In addition, 3D CT can help for surgical planning, such as femoral derotation osteotomy and/or hip arthroscopy or resection of the lesser trochanter.

The impact of symptomatic femoral neck anteversion and tibial torsion on gait, function and participation in children and adolescents

BACKGROUND

Torsional deformities of the lower limbs in children and adolescents are a common cause of in-toeing gait and cause gait deviations. The purpose of this study was to examine the relationship of children and adolescents with suspected Idiopathic Torsional Deformities (ITD) and pain, gait function, activity and participation.

METHODS

A retrospective review of all children and adolescents who attended our Centre over a 5-year period for evaluation of the effect of ITD. All children completed three-dimensional gait analysis (3DGA), standardized physical examination, medical imaging and the Pediatric Outcomes Data Collection Instrument (PODCI). Statistical analysis was completed using two sample t-tests, Pearson's Correlation and linear regression.

RESULTS

Fifty children and adolescents, 40 females and 10 males with a mean age of 13.5 years were included. Children reported a high prevalence of pain(86%), had increased internal hip rotation(p = 0.002) and decreased external hip rotation(p < 0.001) on physical examination when compared to published normative data. Medical imaging showed a mean(SD) femoral neck anteversion (FNA) of 38°(13°) and external tibial torsion of 39°(12°). Mean(SD) PODCI score was 32(16), indicating these children are functioning below their typically developing peers. The 3DGA kinematics show deviations from typical data including hip rotation, foot progression, pelvic tilt, hip flexion and knee extension. Observed mild kinetic deviations were within typical limits. The relationship between FNA and gait parameters, FNA and PODCI and gait and PODCI were weak.

SIGNIFICANCE

These children and adolescents have altered gait and experience pain leading to impaired function and diminished participation. Therefore, ITD is not purely a cosmetic issue.

Dynamic Q-angle is increased in patients with chronic patellofemoral instability and correlates positively with femoral torsion

PURPOSE

The purpose of the study was to evaluate the frontal gait patterns in patients with chronic patellofemoral instability compared to healthy controls. The hypothesis was that internal-rotation-adduction moment of the knee as altered dynamic Q-angle is evident in patients and correlates positively with increased femoral torsion.

METHODS

Thirty-five patients with symptomatic recurrent patellofemoral instability requiring surgical treatment were matched for average age, sex, and body mass index with 15 healthy controls (30 knees). Several clinical and radiographic measurements were taken from each participant: internal and external rotation (hipIR, hipER), Q-angle, tubercle sulcus angle (TS-angle), femoral antetorsion (femAT), tibial tubercle-trochlear groove (TT-TG) distance, and frontal leg axis. Additionally, three frontal gait patterns were defined and recorded: (1) internal-rotation-adduction moment of the knee during normal walking, (2) dynamic valgus of the knee, and (3) Trendelenburg's sign in a single-leg squat. Randomized videography was evaluated by three independent blinded observers. Statistical analysis was performed using regression models and comparisons of gait patterns and clinical and radiological measurements. Furthermore, observer reliability was correlated to gradings of radiological parameters.

RESULTS

Patients showed altered dynamic Q-angle gait pattern during normal walking (p < 0.001) compared to healthy controls (interrater kappa = 0.61), whereas highest observer agreement was reported if femAT was greater than 20° (kappa = 0.85). Logistic regression model revealed higher femAT (18.2° ± 12.5 versus 11.9° ± 7.0 (p = 0.004) as a significant variable, as well as lower TT-TG distance (23.6 mm ± 2.8 vs. 16.6 mm ± 4.9, p = 0.004) on evident dynamic Q-angle gait pattern. Dynamic valgus in a single-leg squat was observed significantly more often in patients (p < 0.001) compared to controls (interrater kappa = 0.7). However, besides the static measured Q-angle as the only significant variable on evident dynamic valgus pattern (13.6° ± 4.6 vs. 10.3° ± 5.2, p = 0.003), no radiological parameter was detected to correlate significantly with dynamic valgus and Trendelenburg's sign (n.s.).

CONCLUSIONS

Clinical detection of pathologic torsion and bony alignment may be difficult in patients with patellofemoral instability. The present study demonstrated that dynamic Q-angle gait pattern is significantly altered in patients with chronic patellofemoral instability compared to healthy controls. Moreover, dynamic Q-angle correlates positively with higher femoral torsion and negatively with higher TT-TG distance. Therefore, clinical and radiological assessment of maltorsion should be added to the standard diagnostic workup in cases of patellofemoral instability.

LEVEL OF EVIDENCE

Level II.

Relationship between kinematic gait parameters during three gait modifications designed to reduce peak knee abduction moment

PURPOSE

Gait modifications designed to change a single kinematic parameter have reduced first peak internal knee abduction moment (PKAM). Prior research suggests unintended temporospatial and kinematic changes occur naturally while performing these modifications. We aimed to investigate i) the concomitant kinematic and temporospatial changes and ii) the relationship between gait parameters during three gait modifications (toe-in, medial knee thrust, and trunk lean gait).

METHODS

Using visual real-time biofeedback, we collected 10 trials for each modification using individualized target gait parameters based on participants' baseline mean and standard deviation. Repeated measures ANOVA was performed to determine significant differences between conditions. Mixed effects linear regression models were then used to estimate the linear relationships among variables during each gait modification. All modifications reduced KAM by at least 5%.

RESULTS

Modifications resulted in numerous secondary changes between conditions such as increased knee abduction during toe-in gait and increased knee flexion with medial knee thrust. Within gait modifications, relationships between kinematic parameters were similar for toe-in gait and medial knee thrust (i.e. increased toe-in and decreased knee abduction), while increased trunk lean showed no relationship with any other kinematic parameters during trunk lean trials.

CONCLUSION

Two main mechanisms were found as a result of this investigation; the first being a pattern of toeing-in, knee abduction, flexion, and internal hip rotation, while trunk lean modification presented as a separate gait pattern with limited secondary changes. Future studies should consider providing feedback on multiple linked parameters, as it may feel more natural and optimize KAM reductions.

Compensatory mechanisms in children with idiopathic lower extremity internal rotational malalignment during walking and running

BACKGROUND

Noticeable in-toeing gait is present in most children with internal rotational malalignment and often a reason to consult an orthopedic specialist. The risk of tripping may be higher for these patients.

RESEARCH QUESTION

The aim of this study was to determine compensatory mechanisms adopted by children with internal rotational deformities to avoid tripping and falling during walking and running.

METHODS

Sixty-nine patients between 5-18 years with idiopathic internal rotational malalignment were retrospectively included and subdivided into three groups: 18 patients with internal tibial torsion (ITT), 25 patients with internal femoral torsion (ITF) and 26 patients with both (ITB). Twenty-two typically developing age-matched children (TD) were analyzed for comparison. Three-dimensional gait data were evaluated. ANOVA's on two factors, group (ITT, ITF, ITB, TD) and movement (walking, running) with post-hoc t-tests were used to identify significant differences between groups.

RESULTS

All groups had significantly greater step width than TD during walking (P ≤ .002) and all torsional groups had significantly greater step width during running (P ≤ .001). Similarly, all torsional groups showed greater peak ankle dorsiflexion in swing during running than TD (P ≤ .006). Only the ITT group showed significantly greater external hip rotation than TD. When compared to TD, the ITF and ITB group had a significantly lower hip abduction moment in stance during running, but not for walking (P ≤ .032).

SIGNIFICANCE

Compensatory mechanisms in children with internal rotational deformities were mostly dependent on the location of rotational malalignment. All children with internal rotational malalignment had greater ankle dorsiflexion and greater step width during running. Especially in active patients, this greater ankle dorsiflexion during running may result in overuse of the ankle dorsiflexor muscles, while greater step width may have beneficial effects in normalizing knee adduction moments.

Application of three-dimensional reconstruction to improve the preoperative measurement accuracy and applicability of femoral neck torsion angle

Conventional methods have limitations in measuring femoral neck torsion angle (FNTA) of patients with femoral deformities. A new method of three-dimensional (3D) reconstruction technology based on computer tomography (CT) was proposed to enhance measurement accuracy and applicability in this study.Bilateral FNTA of 50 developmental dysplasia of the hip (DDH) patients (DDH group) and 81 volunteers (normal group) were measured by Mimics software based on CT data with the marker lines determined by centerline and curvature. Each FNTA was measured by observer A and observer B for twice separately. 50 DDH patients were classified into 3 groups (group I, II, III) according to Hartofilakidis classification. The statistical analysis of the differences was made among the measurements of the FNTA.The FNTA values were 27.56° ± 12.48° in DDH group and 21.22° ± 8.14° in normal group with significant difference (t = 4.516, P < .001). The FNTA values were 24.53° ± 2.40° in group I, 29.78° ± 1.83° in group II and 39.08° ± 3.13° in group III, with significant difference (F = 7.568, P = .001).The accuracy, reliability and applicable scope of FNTA measurement can be improved by 3D reconstruction in clinical practice. The applicable scope of this method included normal people and patients with femoral deformities. The FNTA of DDH patients is significantly larger than normal volunteers with a positive correlation between the severity of classification. This study will also provide references for preoperative design of Chinese population.

Prevalence and diagnostic accuracy of in-toeing and out-toeing of the foot for patients with abnormal femoral torsion and femoroacetabular impingement: implications for hip arthroscopy and femoral derotation osteotomy

AIMS

Abnormal femoral torsion (FT) is increasingly recognized as an additional cause for femoroacetabular impingement (FAI). It is unknown if in-toeing of the foot is a specific diagnostic sign for increased FT in patients with symptomatic FAI. The aims of this study were to determine: 1) the prevalence and diagnostic accuracy of in-toeing to detect increased FT; 2) if foot progression angle (FPA) and tibial torsion (TT) are different among patients with abnormal FT; and 3) if FPA correlates with FT.

PATIENTS AND METHODS

A retrospective, institutional review board (IRB)-approved, controlled study of 85 symptomatic patients (148 hips) with FAI or hip dysplasia was performed in the gait laboratory. All patients had a measurement of FT (pelvic CT scan), TT (CT scan), and FPA (optical motion capture system). We allocated all patients to three groups with decreased FT (< 10°, 37 hips), increased FT (> 25°, 61 hips), and normal FT (10° to 25°, 50 hips). Cluster analysis was performed.

RESULTS

We found a specificity of 99%, positive predictive value (PPV) of 93%, and sensitivity of 23% for in-toeing (FPA < 0°) to detect increased FT > 25°. Most of the hips with normal or decreased FT had no in-toeing (false-positive rate of 1%). Patients with increased FT had significantly (p < 0.001) more in-toeing than patients with decreased FT. The majority of the patients (77%) with increased FT walk with a normal foot position. The correlation between FPA and FT was significant (r = 0.404, p < 0.001). Five cluster groups were identified.

CONCLUSION

In-toeing has a high specificity and high PPV to detect increased FT, but increased FT can be missed because of the low sensitivity and high false-negative rate. These results can be used for diagnosis of abnormal FT in patients with FAI or hip dysplasia undergoing hip arthroscopy or femoral derotation osteotomy. However, most of the patients with increased FT walk with a normal foot position. This can lead to underestimation or misdiagnosis of abnormal FT. We recommend measuring FT with CT/MRI scans in all patients with FAI. Cite this article: Bone Joint J 2019;101-B:1218-1229.

Role of femoral derotation on gait after selective dorsal rhizotomy in children with spastic cerebral palsy

AIM

To evaluate the long-term outcome of selective dorsal rhizotomy (SDR) on gait and the influence of previous femoral derotation osteotomy (FDO).

METHOD

In a retrospective cohort study of 29 children (16 females, 13 males) with spastic diplegic cerebral palsy, 14 children received FDO before SDR, whereas 15 children with moderate or near-normal internal femoral rotation during gait received only SDR. Three-dimensional gait data were obtained pre-FDO, pre-SDR, 1 year post-SDR, and 3 to 5 years post-SDR, to study the Gait Profile Score (GPS), pelvic tilt, and knee and hip kinematics. A mixed analysis of variance with the repeated measure 'time' was performed between different time points for each group.

RESULTS

Children who first underwent FDO and then SDR started with a more complex gait pathology but showed fewer gait deviations 3 to 5 years post-SDR, compared to children who only underwent SDR. This was reflected by a lower GPS and pelvic tilt, as well as less knee flexion in stance.

INTERPRETATION

The effect of SDR on gait is only significant in the mid- to long-term if the bony lever arms are also corrected. Thus, the clinical outcome after SDR is dependent on good proximal alignment.

WHAT THIS PAPER ADDS

Pelvic tilt remains stable after femoral derotation osteotomy (FDO)+selective dorsal rhizotomy (SDR). But pelvic tilt deteriorates after SDR only. Hip and knee extension is better after FDO+SDR than after SDR only. Spasticity reduction (by SDR) combined with bony lever arm correction (by FDO) improves gait.

Reproducibility of the Evolution of Stride Biomechanics During Exhaustive Runs

Running biomechanics and its evolution that occurs over intensive trials are widely studied, but few studies have focused on the reproducibility of stride evolution in these runs. The purpose of this investigation was to assess the reproducibility of changes in eight biomechanical variables during exhaustive runs, using three-dimensional analysis. Ten male athletes (age: 23 ± 4 years; maximal oxygen uptake: 57.5 ± 4.4 ml0₂·min^-1·kg^-1; maximal aerobic speed: 19.3 ± 0.8 km·h^-1) performed a maximal treadmill test. Between 3 to 10 days later, they started a series of three time-to-exhaustion trials at 90% of the individual maximal aerobic speed, seven days apart. During these trials eight biomechanical variables were recorded over a 20-s period every 4 min until exhaustion. The evolution of a variable over a trial was represented as the slope of the linear regression of these variables over time. Reproducibility was assessed with intraclass correlation coefficients and variability was quantified as standard error of measurement. Changes in five variables (swing duration, stride frequency, step length, centre of gravity vertical and lateral amplitude) showed moderate to good reproducibility (0.48 ≤ ICC ≤ 0.72), while changes in stance duration, reactivity and foot orientation showed poor reproducibility (-0.71 ≤ ICC ≤ 0.04). Fatigue-induced changes in stride biomechanics do not follow a reproducible course across the board; however, several variables do show satisfactory stability: swing duration, stride frequency, step length and centre of gravity shift.

Relationship between femoral anteversion and tibial torsion: CT evaluation of 38 unilateral developmental dysplasia of the hip patients

INTRODUCTION

Patients with developmental dysplasia of the hip (DDH) present with a wide spectrum of deformities. Few studies have assessed the relationship between femoral anteversion (FA) and rotational profile. The aim of this study is to evaluate the influence of FA on the lower extremity rotational profile by comparing tibial torsion (TT) between the extremities on both sides in patients with unilateral DDH, using computed tomography (CT).

PATIENTS AND METHODS

Thirty eight patients with unilateral developmental dysplasia of the hip, who underwent a preoperative rotational profile CT scan at our institution, were evaluated. 3D rotational profile CT was performed, and FA and TT of the extremities on both sides were measured.

RESULTS

On individual comparison of the rotational profile, mean FA of the affected extremity showed a significantly higher value ( p = 0.006). But, there was no significant difference in mean TT between the 2 extremities. On group analysis, the excessive FA group (group B) showed significantly higher values of tibial torsion and tibial torsion side-to-side difference compared to the normal FA group (group A) ( p = 0.000, p = 0.011, respectively).

CONCLUSIONS

Our study suggests that patients with DDH can present with excessive FA. Therefore, while treating patients who show excessive FA, surgeons must consider the possibility of a higher rotational profile of the affected extremity, before performing surgical treatments for DDH.

Hip- and patellofemoral-joint loading during gait are increased in children with idiopathic torsional deformities

BACKGROUND

Torsional deformities of the femur and tibia are associated with gait impairments and joint pain. Several studies have investigated these gait deviations in children with cerebral palsy. However, relatively little is known about gait deviations in children with idiopathic torsion and debate ensues about the management of these patients.

RESEARCH QUESTION

What are the effects of idiopathic increased femoral neck anteversion and external tibial torsion on lower-limb kinematics, kinetics and joint loading during gait in children and adolescents.

METHODS

Patient-specific musculoskeletal models were created for 12 children/adolescents (mean age of 14 years) with torsional deformities using low-dose biplane radiographic imaging and 3D gait analysis. Comparisons of joint motion and net joint torques during gait were made to an age-matched control group with no torsional deformities. The effects of torsional deformities on muscle and joint contact forces were investigated using two personalised musculoskeletal models: one with normal torsion and another with patient-specific torsion.

RESULTS

Femoral neck anteversion and external tibial torsion for the patients were (mean ± SD) 38° ± 9° and 40° ± 10°, respectively. Patients had increased internal hip rotation and external knee rotation as well as increased pelvic tilt during gait. Additionally, the efficacy of the plantarflexor-knee extension mechanism was diminished. Hip joint contact force was higher in the model with patient-specific torsion. The mediolateral component of the patellofemoral joint contact force was also increased despite the magnitude of the resultant patellofemoral contact force being unchanged.

SIGNIFICANCE

It has been previously established that idiopathic lower-limb torsional deformities alter gait kinematics. However, this study also showed that loading of the hip and patellofemoral joints are increased. This is an important insight for the clinical management of these patients and highlights that idiopathic lower-limb torsional deformities are not a purely cosmetic issue.

Joint Mechanics After Total Knee Arthroplasty While Descending Stairs

BACKGROUND

Modern knee designs do not fully restore the anatomy and kinematics of the natural knee. This study evaluates the kinematic and kinetic changes of well-functioning patients with total knee arthroplasty (TKA) in comparison to a healthy age-matched control group while descending stairs and level walking. The aim was to have a baseline for further investigations of TKA patients with problems.

METHODS

Fifteen patients satisfied with TKA (8♀/7♂; 66.8 ± 7.4 years; body mass index (BMI) 25.9 ± 2.8 kg/m²; 2.1 ± 1.3 years postop, LCS Complete) and 17 healthy control subjects (7♀/10♂; 66.6 ± 6.8 years; BMI 25.0 ± 2.2 kg/m²) participated in the study. Kinematic (upper and lower body) and kinetic (lower body) data were collected during stair descending (step height 17 cm) and level walking, using an 8-camera Vicon system and 2 force plates. Parameters were compared using a Student t test.

RESULTS

Patients after TKA showed significantly lower frontal knee moments and a more externally rotated hip during stance for both level walking and stair descent. There were 31% more significantly different parameters during level walking than during stair descent.

CONCLUSION

The analysis of stair descending in addition to level walking for satisfied patients does not add additional information for the understanding of the kinematic and kinetic changes after TKA. It seems more important to include the kinematics and kinetics of the hip and ankle joint in all 3-dimensional planes.

Microinstability of the hip: A review

With the development of conservative hip surgery techniques, new entities such as microinstability have been identified. Microinstability is a painful supra-physiological mobility of the hip. It results from the association of architectural and functional abnormalities impairing joint stability. These risk factors concern hip joint bone architecture or peri-articular soft tissues. Bone abnormalities are identified on hip assessment parameters. Soft tissues also play a key role in the static and dynamic stability of the hip: the joint capsule, labrum, ligamentum teres and adjacent myotendinous structures affect joint coaptation; any abnormality or iatrogenic lesion concerning these structures may constitute a risk factor for microinstability. Diagnosis is based on interview, clinical examination and imaging. Findings of labral lesions or femoro-acetabular impingement do not rule out microinstability; they may be associated. Treatment is based first on physiotherapy for muscle reinforcement to improve joint coaptation. In case of failure, arthroscopic surgery is indicated for femoro-acetabular impingement and capsular plicature which is being evaluated. Periacetabular osteotomy or shelf acetabuloplasty may be indicated, according to the severity of joint bone architecture abnormality. Microinstability is a multifactorial entity. Lesions induced by microinstability may in turn become risk factors for aggravation. Diagnosis and indications for surgery are thus difficult to establish. Only full clinical examination and exhaustive imaging assessment allow microinstability and associated lesions to be identified.

The rotational profile: A study of lower limb axial torsion, hip rotation, and the foot progression angle in healthy adults

The purpose of this study was to compare the rotational profile of adults with higher versus lower foot progression angles (FPA). Tibial torsion, femoral torsion, hip internal and external rotation and FPA data were collected on one hundred two healthy volunteers. Data were stratified into Low, Mid, and High FPA groups to study relationships among the components of the rotational profile and if there were group differences in the magnitude of torsion angles. Direction of torsion was also studied as an attempt to look at the incidence of offsetting between the tibia and femur. Tibial torsion was significantly higher in the High FPA group (p<0.001) and was significantly related to the FPA (p≤0.01). Femoral torsion was related to hip internal rotation (p<0.05). Offsetting tibial and femoral torsions occurred in 59% of subjects with low FPA and 56% of subjects with high FPA. All subjects in the low FPA group with offsetting had tibial torsion that followed the FPA and the femurs that were directed opposite. In the High FPA group, 68% of subjects with offsetting had tibias that followed the FPA. Stratifying the data by FPA revealed there were significant differences in tibial torsion among the groups and provided evidence that tibial torsion influences the direction and magnitude of the FPA. Offsetting torsions between the tibia and femur were more common in people with higher and lower FPA and had clearer patterns where the tibia tended to follow the direction of the FPA.