Ethnic-, gender-, and age-related differences in femorotibial angle, femoral antetorsion, and tibiofibular torsion: cross-sectional study among healthy Japanese and Australian Caucasians

Clinical anatomy of the human Achilles subtendons twist - meta-analysis

PURPOSE

This study aimed to provide a comprehensive and current overview of the anatomy of the Achilles tendon (AT) twisted structure, as there is a discrepancy in the literature regarding its rotating morphology.

METHODS

An extensive literature search was conducted across multiple databases to identify all studies that reported relevant data on the AT torsion, with no date or language restrictions applied. Data was extracted and assessed for this meta-analysis following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The quality of the included articles was examined using the anatomical quality assessment (AQUA) tool.

RESULTS

Seven articles (n=690 limbs) were pooled into this meta-analysis. The prevalence of Achilles tendon torsion types was as follows: type II was the most common (46.7%, 95% CI: 31.6-60.9%), followed by type I (44.7%, 95% CI: 29.8-59.0%), and least commonly, type III (8.6%, 95% CI: 1.8-18.8%). Additionally, morphometric analysis, utilizing the method described by van Gils et al., revealed a mean Achilles tendon torsion of 46.5° (95% CI: 25.1-67.9°).

CONCLUSIONS

This meta-analysis underscores the prominent and variable twist within the Achilles tendon among individuals, emphasizing the inherent diversity in AT morphology. Furthermore, the study highlights the importance of considering torsion angle as a potential factor influencing AT pathologies and biomechanical function.

Torsional Deformity Significantly Impacts Lateral Ankle Radiographic Imaging Parameters

Background Optimal lateral ankle imaging is important for the diagnosis and treatment of multiple ankle conditions. The effects of limb deformity on lateral ankle imaging are not well described and are clarified in this osteological study. Materials and methods We utilized an osteological collection and imaged all specimens after the first positioning of the talus in the lateral position and positioning the tibia and fibula to match. We then measured the relative positions of the tibia and fibula and their widths to calculate standard ratios. All measurements were evaluated for reliability using intra-class correlation coefficients. Multiple regression analysis determined how patient characteristics, tibial torsion, and medial proximal tibial angle affected various lateral ankle imaging ratios. Results The intra-class correlation coefficient was excellent for all measurements. In the multiple regression analysis, all five imaging ratios had at least one statistically significant outcome. The anterior tibiofibular interval (ATFI)-tibial width (TW) ratio (ATFI:TW) had only one association with sex and had the lowest standard deviation. All other parameters had variation with tibial torsion and/or medial proximal tibia angle (MPTA). The mean ATFI was 1.06 ± 0.21 cm and 1.19 ± 0.23 cm for females and males, respectively. Conclusions Patient sex and tibial torsion impacted the fidelity of lateral imaging parameters. ATFI:TW may pose the greatest utility given its minimal association with deformity parameters and low standard deviation.

Knee alignment and individual quadriceps femoris muscle thicknesses and their relationships with postnatal motor development and subcutaneous fat thickness: A cross-sectional study in Japanese infants

BACKGROUND

Postnatal changes in individual quadriceps femoris muscle thicknesses and the relationships between knee alignment and quadriceps thicknesses, postnatal motor development, and subcutaneous fat thickness are unclear. This study investigated knee alignment and individual quadriceps thickness ratios in Japanese infants and investigated their relationships with postnatal motor development and subcutaneous fat thickness.

METHODS

One-year-old (n = 28), 2-year-old (n = 26), and 3-year-old infants (n = 22) were included. Postnatal months when the infants began crawling, standing, and walking were assessed. The intercondylar distance was measured, and the individual quadriceps and subcutaneous fat thicknesses at the right mid-thigh were measured using ultrasonography. The individual quadriceps:total quadriceps muscle thickness ratios were calculated. Analysis of variance tests in the 3 groups were conducted for the intercondylar distances and individual quadriceps thickness ratios, and correlation coefficients between the parameters were evaluated in each group.

FINDINGS

Intercondylar distance was longer in 1-year-old infants than in 2-year-old infants (p < 0.001), without significant differences between 2-year-old and 3-year-old infants (p = 0.33). The rectus femoris thickness ratio was higher in 1-year-old infants than in 3-year-old infants (p = 0.013), whereas the vastus medialis thickness ratio was higher in 3-year-old infants than in 2-year-old infants (p = 0.024). In 3-year-old infants, a larger subcutaneous fat thickness, but not postnatal motor development, was correlated with a longer intercondylar distance and a lower vastus medialis thickness ratio (rs = 0.53, p = 0.012; rs = -0.46, p = 0.032, respectively).

INTERPRETATION

Further studies on the relationships between subcutaneous fat and knee alignment and vastus medialis in juveniles, adolescents, young adults, and elderly people are expected.

Correlation of Tibial Torsion With Lower Limb Alignment and Femoral Anteversion in Patients With Patellar Instability

BACKGROUND

Alignment and rotation of the lower extremities have been suggested to be predisposing pathologic factors for patellar instability.

PURPOSE

To elucidate the relationship between the lower limb alignment and lower extremity rotation in patients with patellar instability.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Included were 83 patients with patellar instability. Computed tomography scans and standing full-leg radiographs were used to measure the tibial tuberosity-trochlear groove (TT-TG) distance, mechanical femorotibial angle (mFTA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), femoral torsion, and tibial torsion of the different segments. The relationships between femoral torsion, tibial torsion of the different segments, and the mFTA, mLDFA, and mMPTA were evaluated. The levels of tibial torsion and femoral torsion in patients with varus, normal, or valgus alignment were compared with 1-way analysis of variance and chi-square test.

RESULTS

The total tibial torsion was significantly associated with total femoral anteversion (r = 0.329; P = .002) and mFTA (r = -0.304; P = .005). There were no significant correlations between mFTA and TT-TG distance or femoral anteversion. Compared with patients with valgus malalignment, patients with varus malalignment tended to have higher tibial torsion.

CONCLUSION

Tibial torsion was associated with leg axis alignment and femoral anteversion in patients with patellar instability. Patients with patellar instability, especially those with concurrent leg axis deformities, should undergo further radiological imaging so that tibial torsion can be assessed and a diagnosis of torsion deformity made early in the treatment pathway and the proper surgical plan formulated.

Internal Torsion of the Knee: An Embodiment of Lower-Extremity Malrotation in Patients with Patellar Instability

BACKGROUND

Torsion of the lower extremities has been suggested to be a predisposing factor for patellar instability. However, no clear torsional factors have been clarified. This study aimed to elucidate the rotational geometry of the lower limb through segmental analysis in patients with patellar instability.

METHODS

Eighty-three patients with patellar instability were included. Computed tomography of the lower limb was acquired. Femoral and tibial torsion were measured in different segments. Femoral and tibial torsion in each segment was compared between the high- and normal-torsion groups to investigate which segment contributes the most.

RESULTS

All segments of femoral and tibial torsion except proximal femoral torsion showed significant differences between the high- and normal-torsion groups. The average proximal femoral torsion was 1.9° ± 7.1°, indicating that there was only slight torsion in the segment of the femoral neck. The angle between the femoral neck and the foot orientation in the normal-torsion, high-torsion tibial, and combined high-torsion femoral and tibial groups was 89.1° ± 12.0°, 81.3° ± 9.4°, and 98.2° ± 11.7°, respectively (p < 0.001), which suggested that the femoral neck remained nearly perpendicular to the foot orientation in the normal-torsion group. Shaft and distal femoral torsion contributed the most to total femoral torsion. For tibial torsion, from distal to proximal, internal torsion of both the proximal and distal segments contributed to the high torsion. There was no significant difference between distal femoral torsion and proximal tibial torsion, which suggested that, rather than the distal femur rotating internally on its own, the distal femur and the proximal tibia simultaneously rotated internally.

CONCLUSIONS

In patients with patellar instability, torsional deformity occurs along the length of the tibia and in the shaft and distal segments of the femur. The comprehensive embodiment of lower-extremity malrotation is an internal rotation deformity of the knee.

CLINICAL RELEVANCE

This study elucidated the rotational geometry of the lower limb through a detailed segmental analysis in patients with patellar instability. It could serve as a theoretical basis for choosing a derotational osteotomy site and may be a reference for additional clinical research.

Sex and Limb Differences in Lower Extremity Alignment and Kinematics during Drop Vertical Jumps

Sex and limb differences in lower extremity alignments (LEAs) and dynamic lower extremity kinematics (LEKs) during a drop vertical jump were investigated in participants of Korean ethnicity. One hundred healthy males and females participated in a drop vertical jump, and LEAs and LEKs were determined in dominant and non-dominant limbs. A 2-by-2 mixed model MANOVA was performed to compare LEAs and joint kinematics between sexes and limbs (dominant vs. non-dominant). Compared with males, females possessed a significantly greater pelvic tilt, femoral anteversion, Q-angle, and reduced tibial torsion. Females landed on the ground with significantly increased knee extension and ankle plantarflexion with reduced hip abduction and knee adduction, relatively decreased peak hip adduction, knee internal rotation, and increased knee abduction and ankle eversion. The non-dominant limb showed significantly increased hip flexion, abduction, and external rotation; knee flexion and internal rotation; and ankle inversion at initial contact. Further, the non-dominant limb showed increased peak hip and knee flexion, relatively reduced peak hip adduction, and increased knee abduction and internal rotation. It could be suggested that LEAs and LEKs observed in females and non-dominant limbs might contribute to a greater risk of anterior cruciate ligament injuries.

Healthy middle-aged Asian and Caucasian populations present with large intra- and inter-individual variations of lower limb torsion

PURPOSE

There is a lack of standardization in the measurement of lower limb torsional alignment. Normal values published in the literature are inconsistent. A 3D-CT-scan-based method was used in a healthy population to define the femoral neck version (FNV) and the tibial torsion (TT) and their relationship with demographic parameters. The study objectives were (1) to define normal values of lower limb torsional alignment, (2) to estimate inter- and intra-individual variations of torsional deformity of healthy individuals' lower limbs. The hypothesis was that FNV and TT values would be influenced by patient characteristics such as gender, age, and ethnicity, and would have low side-to-side asymmetry.

METHODS

Torsional landmarks of the lower limbs from 191 healthy subjects were automatically calculated with a 3D CT-scan-based program. The FNV was defined by the angle between the femoral neck axis and the femoral posterior condylar line. The TT angle was considered between the tibial plateau axis and the axis of the ankle. For the former, two alternatives were considered: the line connecting the more medial and lateral point of the medial and lateral plateau, respectively (method 1; TT1), or the line connecting the two more posterior points of the medial et lateral plateau (method 2; TT2). The ankle axis was defined as the line connecting the medial and lateral malleoli. These reference lines were automatically calculated. Age, gender, ethnic group, and BMI were recorded for every subject. A p value < 0.05 was considered as statistically significant.

RESULTS

Overall, the mean FNV was 15.3 ± 9.5° and the mean TT was 31.6 ± 6.3°. Female hips were more anteverted than male hips. Caucasians had less anteverted hips than Asians, but more externally rotated tibias. Age and BMI were not correlated with any anatomical parameter. A substantial side-to-side asymmetry was found for FNV [absolute difference (AD) = 6.3°; percentage of asymmetry (%As) = 47%], TT1 (AD = 3°; %As = 12%), and TT2 (AD = 4.9°; %As = 9%) (p = 0.008).

CONCLUSION

The findings showed that lower limb torsional parameters were highly variable from patient to patient and from one leg to the other for the same patient. The understanding of normal values concerning femoral version and external tibial torsion in the present healthy population will help surgeons to define pathological values of FNV and TT, as well as corrections to perform in case of torsional deformities.

LEVEL OF EVIDENCE

Level III.

Neutral alignment resulting from tibial vara and opposite femoral valgus is the main morphologic pattern in healthy middle-aged patients: an exploration of a 3D-CT database

PURPOSE

Given the goal of achieving optimal correction and alignment after knee arthroplasty or high tibial osteotomy, literature focusing on the inter-individual variability of the native knee, tibia and femur with regards to the coronal or sagittal alignment is lacking. The aim of this study was to analyse normal angular values in the healthy middle-aged population and determine differences of angular values according to inter-individual features. The first hypothesis was that common morphological patterns may be identified in the healthy middle-aged non-osteoarthritic population. The second hypothesis was that high inter-individual variability exists with regards to gender, ethnicity and alignment phenotype.

METHODS

A CT scan-based modelling and analysis system was used to examine the lower limb of 758 normal healthy patients (390 men, 368 women; mean age 58.5 ± 16.4 years) with available data concerning angular values and retrieved from the SOMA database. The hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA) and non weight-bearing joint line convergence angle (nwJLCA) were then measured for each patient. Results were analysed for the entire cohort and based on gender, ethnicity and phenotype.

RESULTS

The mean HKA was 179.4° ± 2.6°, LDFA: 85.8° ± 2.0°, MPTA: 85.6° ± 2.4°, PDFA: 85.2° ± 1.5°, PPTA: 83.8° ± 2.9° and nwJLCA: 1.09° ± 0.9°. Gender was associated with higher LDFA and lower HKA for men. Ethnicity was associated with greater proximal tibial vara and distal femoral valgus for Asian patients. Patients with an overall global varus alignment had more tibia vara and less femoral valgus than patients with an overall valgus alignment.

CONCLUSION

Even if significant differences were found based on subgroup analysis (gender, ethnicity or phenotype), this study demonstrated that neutral alignment is the main morphological pattern in the healthy middle-aged population. This neutrality is the result from tibia vara compensated by an ipsilateral femoral valgus.

LEVEL OF CLINICAL EVIDENCE

III, retrospective cohort study.

Mismatched knee implants in Indonesian and Dutch patients: a need for increasing the size

PURPOSE

The aim of this study was to evaluate the anthropometric differences between knees of Indonesian Asians and Dutch Caucasians and the fit of nine different knee implant systems.

METHODS

A total of 268 anteroposterior (AP) and lateral knee preoperative radiographs from 134 consecutive patients scheduled for total knee arthroplasty at two different centres in Jakarta and Leiden were included. Both patient groups were matched according to age and sex and included 67 Asians and 67 Caucasians. We assessed the radiographic differences between the Asian and Caucasian anthropometric data. The dimensions of the nine knee implant designs (Vanguard, Genesis II, Persona Standard, Persona Narrow, GK Sphere, Gemini, Attune Standard, Attune Narrow, and Sigma PFC) were compared with the patients' anthropometric (distal femur and proximal tibia) measurements.

RESULTS

The Dutch Caucasian patients had larger mediolateral (ML) and AP femoral and tibial dimensions than the Indonesian Asians. The aspect ratios of the distal femur and tibia were larger in Asians than in Caucasians. The AP and ML dimensions were mismatched between the tibial components of the nine knee systems and the Asian anthropometric data. Both groups had larger ML distal femoral dimensions than the knee systems.

CONCLUSION

Absolute and relative differences in knee dimensions exist not only between Asian and Caucasian knees but also within both groups. Not all TKA systems had a good fit with the Asian and Caucasian knee phenotypes. An increase in the range of available knee component sizes would be beneficial, although TKA remains an adequate compromise.

LEVEL OF EVIDENCE

III.

Tibial Torsion and Patellofemoral Pain and Instability in the Adult Population: Current Concept Review

PURPOSE OF REVIEW

Tibial torsion is a recognized cause of patellofemoral pain and instability in the paediatric population; however, it is commonly overlooked in the adult population. The aim of this review article is to summarize the current best evidence on tibial torsion for the adult orthopaedic surgeon.

RECENT FINDINGS

The true incidence of tibial torsion in the adult population is unknown, with significant geographical variations making assessment very difficult. CT currently remains the gold standard for quantitatively assessing the level of tibial torsion and allows assessment of any associated femoral and knee joint rotational anomalies. Surgical correction should only be considered after completion of a course of physiotherapy aimed at addressing the associated proximal and gluteal weakness. Tibial torsion greater than 30° is used as the main indicator for tibial de-rotation osteotomy by the majority of authors. In patients with associated abnormal femoral rotation, current evidence would suggest that a single-level correction of the tibia (if considered to be a dominant deformity) is sufficient in the majority of cases. Proximal de-rotational osteotomy has been more commonly reported in the adult population and confers the advantage of allowing simultaneous correction of patella alta or excessive tubercle lateralization. Previous surgery prior to de-rotational osteotomy is common; however, in patients with persistent symptoms surgical correction still provides significant benefit. Tibial torsion persists into adulthood and can play a significant role in patellofemoral pathology. A high index of suspicion is required in order to identify torsion clinically. Surgical correction is effective for both pain and instability, but results are inferior in patients with very high pain levels pre-surgery and multiple previous surgeries.

Femoral anteversion: significance and measurement

Femoral neck anteversion (FNA) is the angle between the femoral neck and femoral shaft, indicating the degree of torsion of the femur. Differences in FNA affect the biomechanics of the hip, through alterations in factors such as moment arm lengths and joint loading. Altered gait associated with differences in FNA may also contribute to the development of a wide range of skeletal disorders including osteoarthritis. FNA varies by up to 30° within apparently healthy adults. FNA increases substantially during gestation and thereafter decreases steadily until maturity. There is some evidence of a further decrease at a much lower rate during adulthood into old age, but the mechanisms behind it have never been studied. Development of FNA appears to be strongly influenced by mechanical forces experienced during everyday movements. This is evidenced by large differences in FNA in groups where movement is impaired, such as children born breech or individuals with neuromuscular conditions such as cerebral palsy. Several methods can be used to assess FNA, which may yield different values by up to 20° in the same participant. While MRI and CT are used clinically, limitations such as their cost, scanning time and exposure to ionising radiation limit their applicability in longitudinal and population studies, particularly in children. More broadly, applicable measures such as ultrasound and functional tests exist, but they are limited by poor reliability and validity. These issues highlight the need for a valid and reliable universally accepted method. Treatment for clinically problematic FNA is usually de-rotational osteotomy; passive, non-operative methods do not have any effect. Despite observational evidence for the effects of physical activity on FNA development, the efficacy of targeted physical activity remains unexplored. The aim of this review is to describe the biomechanical and clinical consequences of FNA, factors influencing FNA and the strengths and weaknesses of different methods used to assess FNA.

Axial and rotational alignment of lower limb in a Caucasian aged non-arthritic cohort

Background

The alignment of human lower limb has been an area of ongoing study for decades. The purpose of this study was to analyze the axial and rotational alignment from hip to ankle in a Caucasian aged non-arthritic cohort.

Methods

A non-arthritic cohort of aged patients was retrospectively analyzed by computer tomography. Anatomical–mechanical angle of femur (AMA), femur inclination (FI), femoral anteversion (FA), posterior condylar angle (PCA), proximal tibial torsion (TEAs-PTC and TEAs-PTT) and tibial fibular torsion (PTC-TFA) were measured.

Results

The median age of the patients was 76 years (range 67 to 91 years). Regarding axial alignment, the AMA was 5 (2.94; 6.80). No significance differences were reported by side and age. AMA was significantly lower in men. The FI was 125.3 (120.0; 134.8) with no differences in terms of side, age or gender. Regarding torsion alignment, the median values of FA, PTC-TFA and TEAs-PTT were, respectively, 16.8, 28.5 and − 1.4. No differences were reported by age. Right tibia was externally rotated by 1.5 degrees as compared to the left side (P 0.035).

Conclusion

The broad variability of the parameters analyzed highlights the necessity for a more anatomical and individualized approach during surgery of lower limb. The present study offers the fundament to understand and treat lower limb deformities. Hence, these data can constitute the normal reference values useful to investigate lower limb malalignment. Moreover, it helps to assess the possible changes of axial and rotational alignment in idiopathic OA of lower limb.

Level of evidence III

Retrospective cohort study

The Twist of the Achilles Tendon - Associations of Torsions in the Lower Extremity

Achilles tendinopathy and rupture of the Achilles tendon (AT) are frequent pathologies. Even though they may be associated with the twisted morphology of the AT, quantitative data on the extent of the twist of the entire AT are not available. The aim of this study was to investigate the torsion of the AT based on its individual parts and to evaluate a possible correlation with the torsion of the long bones of the lower extremity. Forty embalmed lower extremities were included in this study. The lateral deviation of the AT and its torsional angle as well as the angles of the individual parts in trans-section were measured. Thereafter, the torsions of femur and tibia were evaluated. Measuring the lateral deviation of the fibers resulted in an average torsion of the AT of 34.59° (SD 16.8°). The angles of the different parts of the AT in trans-section resulted in a median AT torsion of 15.73°, showing various patterns of rotations of the individual muscles. A statistically significant correlation between the torsions of the lower extremity and the AT (P =0.0242, r = 0.40) as well as a correlation between the femoral torsion and the AT torsion (P = 0.0127, r = 0.44) were found. This study adds to the morphological understanding of the torsion of the AT and its correlation with the torsions of the long bones of the lower extremity. Especially, the torsion of the femur seems to be connected to the torsion of the tendon. Clin. Anat. 31:1085-1091, 2018. © 2018 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

Neuromuscular adaptations in older males and females with knee osteoarthritis during weight-bearing force control

BACKGROUND

Females exhibit significantly greater incidence, prevalence, and severity of osteoarthritis (OA) compared to males. Despite known biological, morphological, and functional differences between males and females, there has been little sex-related investigation into sex-specific biomechanical and neuromuscular responses to OA.

OBJECTIVE

To identify sex-related differences in OA-affected adults and within-sex differences between healthy and OA-affected adults' muscular activation patterns during lower limb loading.

METHODS

Thirty adults with OA and 36 controls completed a standing ground reaction force (GRF) matching protocol requiring participants to expose equal body weight to each leg and modulate horizontal GRFs while maintaining constant joint positions. Electromyography was plotted as a function of GRF direction to depict muscle activation patterns. Muscles were classified as a general joint stabilizer, specific joint stabilizer or moment actuator by quantifying activation patterns with a test of asymmetry, specificity index and mean direction of activity. Lower limb kinematics and kinetics were also recorded.

RESULTS

In general, muscle roles as it relates to joint stability did not differ between groups. Compared to controls, both males and females with OA demonstrated greater rectus femoris activity and reduced knee rotation moments. Females with OA had significantly greater biceps femoris and gastrocnemius activity during respective lateral, and anterior-medial loading directions compared to males with OA.

CONCLUSIONS

We identified fundamental differences in muscular stabilization strategies in older adults with OA as well as sex-related changes in neuromuscular function that may influence joint loading conditions and provide insight into the greater incidence of knee OA in females.

Responsiveness of the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Oxford Knee Score (OKS) in Japanese patients with high tibial osteotomy

BACKGROUND

To assess responsiveness of the Japanese Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Oxford Knee Score (OKS) in patients undergoing open-wedge HTO to treat knee osteoarthritis and/or osteonecrosis.

METHODS

Patients completed a set of questionnaires before HTO surgery (baseline) and 1 year after surgery. The questionnaires comprised the validated Japanese versions of the KOOS, the OKS, and the SF-36v2 and a visual analogue scale (VAS) for local knee pain and general pain. The treating surgeon completed the Japanese Orthopedic Association (JOA) score for osteoarthritic knees. The study included 119 patients aged 64.7 ± 8.3, 116 were followed at 1 year. 90 patients had knee osteoarthritis (OA) solely. 28 patients suffered from both OA and osteonecrosis (ON); one patient had ON only. Responsiveness to change was assessed using the effect size (ES) between the baseline and the 1-year postoperative assessment and standardized response mean. A distribution-based approach was used to determine the minimally detectable change (MDC95) for the KOOS subscales, and the OKS.

RESULTS

All instruments demonstrated statistically significant changes between the preoperative assessments and one year after surgery. All changes showed an improvement in score, but the condition-specific measures revealed higher responsiveness than the generic measures. All KOOS subscales, the OKS, the local pain VAS, and the JOA score showed large ESs (ES > 1.24) and SRMs (SRM>1.04). At a 95% confidence level, the respective MDCs were 15.83, 18.94, 15.22, 18.99 and 17.23 for the KOOS-Pain, KOOS-Symptoms, KOOS-ADL, KOOS-Sport/Rec, and KOOS-QOL subscales, respectively. The MDC95 for the OKS was 8.29.

CONCLUSIONS

Both, the KOOS and OKS are responsive for use in Japanese-speaking patients with knee osteoarthritis and/or osteonecrosis who are undergoing HTO.

Risk of vascular injury when screw drilling for tibial tuberosity transfer

PURPOSE

During tibial tubercle transfer, popliteal vessels are at risk from drills and screws. The risk is around 0.11%, as described in the literature. We reviewed knee injected CT scan for analysis of the location of arteries, identified landmarks allowing minimizing risks, and defined a safe zone.

MATERIAL AND METHOD

Distances between the posterior cortex and arteries were measured on CT scans from 30 adults (60 knees) at three levels (proximal part of the tibial tuberosity, 20 mm and 40 mm distally). Data were used to create a "risk map" with different angular sectors where the frequency of the presence of arteries was analyzed in each area. We also analyzed the position of 68 screws of 47 patients who underwent a medial tibial tuberosity transfer.

RESULTS

The nearest distance between artery and the posterior tibial cortex was found at the level corresponding to the top of the tuberosity with less than 1 mm, while the largest distance was found at the distal level. We were able to define a safe zone for drilling through the posterior tibial cortex which allows a safe fixation for the screws. This zone corresponds to the medial third of the posterior cortex. When the safe zone is not respected, screws that overtake the posterior cortex may be close to arteries as observed for 37 of the 68 screws analyzed.

CONCLUSION

We described new landmarks and recommendations to avoid this complication during tibial tuberosity transfer.

Union, Knee Alignment, and Clinical Outcomes of Patients Treated With Autologous Bone Grafting for Medial Tibial Defects in Primary Total Knee Arthroplasty

Autologous bone grafting is an established method to overcome bone deficiencies in primary total knee arthroplasty (TKA). However, recently, metal augments have been used by many surgeons. Although autologous bone grafting is a common technique, few large studies have described its success in achieving bone union in primary TKA. The goal of this study was to evaluate primary TKA with autologous bone grafting for tibial defects. A total of 68 knees that had undergone arthroplasty with autologous bone grafting with more than 1 year of follow-up were evaluated. Average follow-up was 6.6 years (range, 1.2-14.6 years). The autologous bone grafting procedure attached the proximal portion of the tibial resection from the lateral side to the bone graft on the medial side with 2 screws. The prosthesis, which had a standard and nonrevision stem, was implanted with cement. Bone union was assessed with fluoroscopic radiography with a weight-bearing anteroposterior view. The rate of bone union was 97% (65 knees). Correction of preoperative alignment was achieved and maintained until final follow-up. Postoperative knee angle and knee and function scores showed significant improvement. One infection occurred, but there were no local complications, such as backout of screws or collapse of bone grafts. The authors believe that autologous bone graft within TKA is a relatively simple and effective procedure that provides good bone union. [Orthopedics. 2017; 40(4):e604-e608.].

The Quadriceps Vector is Most Parallel to the Spherical Axis With Minimal Difference for Gender or Ethnicity

BACKGROUND

The extensor mechanism may be the key to kinematic alignment of total knee arthroplasty. The purpose of this study was to determine any differences in the direction of the quadriceps vector based on gender or ethnicity and to determine which anatomically derived alignment axis is closest to the quadriceps vector.

METHODS

Computed tomography scans and patient records for 14 Caucasians (9 men and 5 women) and 40 Japanese (19 men and 21 women) were evaluated. Three axes of alignment-anatomic, mechanical, and spherical-were identified, measured, and compared to the quadriceps vector in each case. Principal component analysis was used to determine the quadriceps vector by using 3-dimensional models of muscles on computed tomography scans.

RESULTS

No statistically significant differences in the orientation of the quadriceps vector were found based on gender or ethnicity, and the quadriceps vector was most closely aligned with the spherical axis.

CONCLUSION

Because the quadriceps is the primary knee extensor, the spherical axis therefore may be a ubiquitous guide to alignment of the arthroplasty knee based on motion.

In vivo Kinematics of the Knee after a Posterior Cruciate-Substituting Total Knee Arthroplasty: A Comparison between Caucasian and South Korean Patients

Purpose

This study compared in vivo kinematic differences between Caucasian and South Korean patients after a posterior-substituting total knee arthroplasty (PS-TKA).

Materials and Methods

In vivo motions of 9 Caucasian and 13 South Korean knees with a PS-TKA during weight bearing single leg lunge were determined using a dual fluoroscopic imaging technique. Normalized tibiofemoral condylar motions and articular contact locations were analyzed.

Results

Femoral condylar motions of the two groups showed a similar trend in anteroposterior translation, but the South Korean patients were more anteriorly positioned than the Caucasian patients at low flexion and maximal flexion angles in both medial and lateral compartments (p<0.05). Mediolateral femoral condyle translations were similar between the two groups. For tibiofemoral articular contact kinematics, the South Korean patients had significantly more anterior contact locations at the medial compartment at low flexion angles, and more lateral contact locations at the lateral compartment at 0° and 90° flexion compared to the Caucasian patients (p<0.05). The South Korean patients had significantly larger distances between the medial and lateral contact locations at 60° and 90° flexion compared to the Caucasian patients (p<0.05).

Conclusions

The study revealed that while the Caucasian and South Korean knees had similar femoral condylar motions, after PS-TKA the South Korean patients showed different articular contact point kinematics compared to the Caucasian patients.

Passive Hip Range of Motion Predicts Femoral Torsion and Acetabular Version

BACKGROUND

Orientation abnormalities of the acetabulum and femur have been implicated in early-onset coxarthrosis. The purpose of this study was to identify clinical examination findings predictive of such hip morphologies.

METHODS

A consecutive cohort of 221 patients (442 hips) undergoing hip arthroscopy was included. Demographic characteristics including age, diagnosis, sex, height, weight, body mass index (BMI), and physical activity level were recorded. Passive range of motion was measured for all hips. Preoperative computed tomography scans were utilized to measure femoral torsion and central acetabular version, and a combined femoral torsion-acetabular version (COTAV) index was defined as their sum.

RESULTS

The study cohort comprised 221 patients (sixty-four males, 157 females) with a mean age of 32.5 years and mean BMI of 24.2 kg/m(2). Overall, hips with femoral antetorsion and acetabular anteversion exhibited the greatest internal rotation range of motion at a neutral hip position (mean, 44.2°), whereas hips with femoral retrotorsion and acetabular retroversion demonstrated the lowest corresponding value (20.1°; p < 0.001). Femoral torsion was significantly associated with female sex (p < 0.001), BMI (p < 0.001), and presence of pathology corresponding to cam-type femoroacetabular impingement (FAI) (p = 0.044). Central acetabular version was significantly associated with age (p = 0.021), female sex (p < 0.001), and absence of mixed-type FAI pathology (p = 0.025). Increasing age and internal rotation range of motion at a neutral hip position were the most significant predictors of an increased COTAV index.

CONCLUSIONS

This study confirmed that passive hip range of motion significantly predicts combined femoral torsion and central acetabular version. Accurate clinical assessment of the COTAV index may inform surgical decision-making in hip preservation surgery.

Anthropometric difference of the knee on MRI according to gender and age groups

The purpose of this study was to analyze the anthropometric data from MRI images that were obtained from the non-arthritic knees in Asian adults, and to identify the existence of morphologic differences between age groups. This cross-sectional study included knee MR images of 535 patients (273 males, 262 females) taken for the evaluation of soft-tissue injuries, excluding cases with cartilage defect and malalignment. The age, gender, height, and BMI were also assessed. The patients were grouped into three different 20-year age groups (20-39, 40-59, and 60-79). The MRI analysis was performed on the anthropometric parameters of distal femur and posterior tibial slope. Age-related differences were found in femoral width, distance from the distal and posterior cartilage surface to the medial/lateral epicondyle, medial posterior condylar offset (PCO), and posterior condylar angle (PCA) (all P < 0.001), but not in lateral PCO, and medial/lateral tibial slopes. In the analysis of covariance analyses, significant interaction between gender and age groups was found in most parameters, but not in PCA, distance from the posterior cartilage surface to the medial epicondyle, or medial tibial slope. We found anthropometric differences among age groups exist in most of distal femoral parameters, but not in posterior tibial slope. The results of this study can be used by manufacturers to modify prostheses to be suitable for the future Asian elderly population.

Prevalence and risk factor analysis of lower extremity abnormal alignment characteristics among rice farmers

BACKGROUND

Rice farming activities involve prolonged manual work and human-machine interaction. Prolonged farming risk-exposure may result in lower limb malalignment. This malalignment may increase the risk of lower extremity injury and physical disabilities. However, the prevalence and factors associated with lower extremity malalignment have not yet been reported. This study aimed to investigate the prevalence and risk factors of lower extremity malalignment among rice farmers.

METHODS

A cross-sectional survey was conducted with 249 rice farmers. Lower extremity alignment assessment included: pelvic tilt angle, limb length equality, femoral torsion, quadriceps (Q) angle, tibiofemoral angle, genu recurvatum, rearfoot angle, and medial longitudinal arch angle. Descriptive statistics were used to analyze participant characteristics and prevalence of lower extremity malalignment. Logistic regression analysis was used to identify risk factors.

RESULTS

The highest prevalence of lower extremity malalignment was foot pronation (36.14%), followed by the abnormal Q angle (34.94%), tibiofemoral angle (31.73%), pelvic tilt angle (30.52%), femoral antetorsion (28.11%), limb length inequality (22.49%), tibial torsion (21.29%), and genu recurvatum (11.24%). In females, the risk factors were abnormal Q angle, tibiofemoral angle, and genu recurvatum. Being overweight was a risk factor for abnormal pelvic tilt angle, Q angle, and tibiofemoral angle. Age was a risk factor for limb length inequality. Years of farming were a major risk factor for abnormal Q angle, tibiofemoral angle, and foot malalignment.

CONCLUSION

Prevalence of lower extremity malalignment was reported in this study. Female sex, being overweight, and years of farming were major risk factors for lower extremity malalignment. Lower extremity screening should assist in the identification of foot and knee malalignment in rice farmers. This may then lead to early prevention of musculoskeletal disorders arising from such malalignment.

The use of contralateral knee magnetic resonance imaging to predict meniscal size during meniscal allograft transplantation

PURPOSE

The purpose of this study was to determine the size of each meniscus and compare it with the contralateral limb using conventional knee magnetic resonance imaging (MRI) taken from previously uninjured, healthy, young volunteers.

METHODS

The knee joints of 60 healthy volunteers (aged 21 to 43 years, 30 men and 30 women) were enrolled in this study. Standard 3.0-T MRI in a controlled setting was used. By use of the mid-coronal images, the height and width of each medial and lateral meniscus were measured. By use of the mid-sagittal images, the height and width of the anterior and posterior horns of each meniscus was measured. The whole length spanning from the most anterior margin to the most posterior margin of each meniscus was also measured. Mean, standard deviation, and 95% confidence interval values were determined for each measurement.

RESULTS

There were 3 incomplete discoid lateral menisci (10%) in men and 2 incomplete discoid menisci (6.7%) in women. The study group with non-discoid knees comprised 27 men and 28 women. The power of this study ranged from 0.57 to 0.66. All values showed good reliability (intraclass correlation coefficient range, 0.887 to 0.974). There were no significant differences between right and left menisci (all P > .05). There were significant differences between genders. All parameters showed significant differences (P < .05) except the medial meniscus width (P = .221).

CONCLUSIONS

In this small subset of patients, there were no differences between right and left meniscal measurements according to MRI. Therefore, when one is performing meniscal allograft transplantation, contralateral knee MRI may be useful to determine the required size. Identifying both the overall width and length of each meniscus is important when preparing an allograft.

CLINICAL RELEVANCE

Contralateral knee MRI may be used for more accurate meniscal size measurement in patients undergoing meniscal allograft transplantation.

Temporal trends in femoral diaphyseal torsional asymmetry among the Arikara associated with postural behavior

Average femoral torsion has been reported to differ among populations, and several studies have observed a relatively high prevalence of femoral anteversion asymmetry in Native Americans, especially females. This study investigates sexual dimorphism and temporal trends in femoral torsional asymmetry among the Arikara from the seventeenth to the early nineteenth century. To establish if there are population differences, femoral torsion was first measured using a direct method on a diverse comparative sample of Native Americans from the Southwest, Midwest, and Great Plains as well as American Whites and Blacks. To examine temporal trends among the Arikara, femoral torsion was examined using the orientation of the maximum bending rigidity at subtrochanteric in 154 females and 164 males from three temporal variants of the Arikara Coalescent tradition. There is significant sexual dimorphism in femoral torsional directional and absolute asymmetry among most Native American samples, but not among American Whites and Blacks. Among the Arikara there is significant sexual dimorphism in femoral torsional asymmetry in all three temporal variants, and asymmetry in femoral torsional asymmetry increased significantly from the protohistoric to the early historic period among females. The increased femoral torsional asymmetry is likely associated with a common side-sitting posture observed in historic photographs of Great Plains females. Historic Arikara females may have habitually sat in this compulsory position for extended periods while conducting domestic chores. The dramatic change from the protohistoric to historic period suggests a cultural change in sitting posture among females that was widespread across the Northern Plains.

The physiological range of femoral antetorsion

INTRODUCTION

Intramedullary nailing is a common method for fixation of femoral diaphyseal shaft fractures. However, postoperative malrotation does occur in 20-30 % of patients, as intraoperative assessment of antetorsion remains difficult. The estimated average antetorsion angle is 15°. However, it is not clear whether antetorsion correlates with individual characteristics such as age, gender, or femoral length. This information may help surgeons to better estimate the correct target rotation before and during surgery.

MATERIALS AND METHODS

The antetorsion of 211 healthy femurs was measured using torsion difference CTs according to the technique published by Jend. Correlations with age, gender, and femoral length were calculated.

RESULTS

A significant negative correlation of age and antetorsion was found for women aged 0-20. Older women and men did not show any correlation between antetorsion and age. There was no correlation between antetorsion and femoral length. Mean values differed between 17.8° ± 8.9° and 22.7° ± 10.7° in women and 15.3° ± 8.0° and 21.4° ± 9.7° in men.

CONCLUSIONS

Antetorsion is mostly independent of body height and age, the latter except in women younger than 20. The so-far-estimated physiologic antetorsion of about 15° seems to be a little higher in most people.

Mechanical contributors to sex differences in idiopathic knee osteoarthritis

The occurrence of knee osteoarthritis (OA) increases with age and is more common in women compared with men, especially after the age of 50 years. Recent work suggests that contact stress in the knee cartilage is a significant predictor of the risk for developing knee OA. Significant gaps in knowledge remain, however, as to how changes in musculoskeletal traits disturb the normal mechanical environment of the knee and contribute to sex differences in the initiation and progression of idiopathic knee OA. To illustrate this knowledge deficit, we summarize what is known about the influence of limb alignment, muscle function, and obesity on sex differences in knee OA. Observational data suggest that limb alignment can predict the development of radiographic signs of knee OA, potentially due to increased stresses and strains within the joint. However, these data do not indicate how limb alignment could contribute to sex differences in either the development or worsening of knee OA. Similarly, the strength of the knee extensor muscles is compromised in women who develop radiographic and symptomatic signs of knee OA, but the extent to which the decline in muscle function precedes the development of the disease is uncertain. Even less is known about how changes in muscle function might contribute to the worsening of knee OA. Conversely, obesity is a stronger predictor of developing knee OA symptoms in women than in men. The influence of obesity on developing knee OA symptoms is not associated with deviation in limb alignment, but BMI predicts the worsening of the symptoms only in individuals with neutral and valgus (knock-kneed) knees. It is more likely, however, that obesity modulates OA through a combination of systemic effects, particularly an increase in inflammatory cytokines, and mechanical factors within the joint. The absence of strong associations of these surrogate measures of the mechanical environment in the knee joint with sex differences in the development and progression of knee OA suggests that a more multifactorial and integrative approach in the study of this disease is needed. We identify gaps in knowledge related to mechanical influences on the sex differences in knee OA.

Clinical evaluation of hip joint rotation range of motion in adults

INTRODUCTION

Data on hip joint rotation range of motion (ROM) are rare; the methods of measurement vary and reproducibility has not been evaluated, in particular in relation to the subject's position (prone or supine, seated).

HYPOTHESIS

Hip joint rotation ROM is symmetrical, and ROM is not modified by the patient's position when data is obtained.

PATIENTS AND METHODS

This series included 120 adults between 20 and 60 years old (71 women, 49 men), who had no hip, spine or lower extremity disorders. External (ER) and internal (IR) rotation ROM was obtained using a photographic method by two observers. Measurements were obtained with the patient in three positions: the dorsal decubitus (supine) (P1), and ventral decubitus (prone) (P2) with the hip in extension and seated with the hip in flexion (P3).

RESULTS

Hip rotation ROM was P1: 68.1° (ER=38.5°; IR=29.6°); P2: 77.1°(ER=41.8°; IR=35.2°); P3: 78.5° (ER=78.5°; IR=37.9°) with no significant difference among the three positions. Interobserver reproducibility was satisfactory (concordance correlation coefficient (ccc) 0.7) and was comparable in the three positions with a ccc of 0.7072 (P1), 0.7426 (P2) and 0.7332 (P3), respectively. Hip rotation ROM balance was ER predominant in 47.5%, neutral in 39.5% and IR predominant in 13%. Hip rotation ROM balance was symmetric in both hips in 73 subjects (61%). Hip rotation ROM was reduced with age (P<0.0001), and was 4.7° less in men (P=0.0078), and in overweight subjects (P<0.0006).

DISCUSSION

Our values are probably lower than those in the literature because of the difference in study population. In our series, age, BMI and gender seemed to be determining factors. Hip rotation ROM balance is usually ER predominant or neutral. Hip rotation ROM can be measured in the three positions with no significant difference, with satisfactory interobserver reproducibility for each.

TYPE OF STUDY

Diagnostic prospective study: level III.

Three-dimensional morphology of the knee reveals ethnic differences

BACKGROUND

Studies have demonstrated sex differences in femoral shape and quadriceps angle raising a question of whether implant design should be sex-specific. Much of this research has addressed shape differences within the Caucasian population and little is known about differences among ethnic groups.

QUESTIONS/PURPOSES

We therefore asked: Do shape differences in the distal femur and proximal tibia exist among different ethnic groups and between the sexes in each ethnic population? And if ethnic differences exist, do they have a clinical impact on current TKA design?

SUBJECTS AND METHODS

We analyzed 1000 normal adult knees (80 African American, 80 East Asian, and 860 Caucasian). Three-dimensional surface models were created for each bone and added to three-dimensional statistical bone atlases. Statistical shape analysis was conducted with a process combining principal components and multiple discriminate analyses. Eleven femoral and nine tibial measurements were calculated.

RESULTS

We found differences in mean measurements between the sexes and ethnicities. Males had larger knees, with a mean 5-mm-larger anteroposterior dimension than females in all ethnicities. African American females had a 7.4-mm-deeper patellar groove, 2.3-mm-smaller tibial mediolateral dimension, and 2.5-mm-larger tibial anteroposterior dimension than Caucasian females. African American males had a 4.3-mm-larger femoral anteroposterior dimension, 10.1-mm-larger tibial mediolateral dimension, and 6-mm-larger tibial anteroposterior dimension than Asian males.

CONCLUSIONS

We identified differences in three-dimensional knee morphology among Caucasian, African American, and East Asian populations. Clinical studies will be required to determine whether these differences are important for implant design.

The sex specificity of hip-joint muscles offers an explanation for better results in men after total hip arthroplasty

PURPOSE

Choosing a surgical approach for total hip arthroplasty (THA) has a patient-specific impact on peri-operative muscle damage as well as postoperative functional outcome. Women and aged patients increasingly benefit from minimally invasive surgical procedures. For this reason, and due to the distinctly different bony anatomy of men and women, the hypothesis of this study is that muscle distribution around the hip joint is dependent on sex and age. The goal of this study was to analyse hip musculature in men and women and to correlate total muscle volume distribution.

METHODS

From 93 computed tomography (CT) scans of the pelvis (45 men, 48 women) volumes of gluteus medius (GMV), gluteus maximus (GXV) and tensor faciae latae (TFL) muscles were measured on both sides of the pelvis. The distribution of muscle volumes was normalised to patient weight and then correlated with sex and age.

RESULTS

The measured muscle volumes featured no major differences between the left and the right side. The absolute total volume of the hip-encompassing muscular system (TMV) is bigger in men than in women. Correlations between TMV and collected data were observed in both sexes in relation to body weight and size (men p < .00001; women p 0.001). With increased body weight, the TMV of the male patients increased progressively (women 11.2 cm TMV/kg KG vs. men 17.4 cm TMV/kg KG) (p 0.04). The relative distribution of each muscle volume (GMV, GXV, TFL) around the hip joint showed no major differences with respect to sex and/or age (p 0.986 and 0.996, respectively).

CONCLUSIONS

The equal relative muscle distribution in men and women around the hip joint reflects neither sex-related differences observed in clinical outcomes after THA nor bony anatomy. Yet men exhibited more muscle reserves (muscle volume; absolute and in relation to body mass) , which could explain the better outcome in men after THA. Furthermore, this suggests the extraordinary importance of muscle-sparing surgical approaches in women. The results represent the rationale for designing and analysing future studies of sex-specific therapies with regard to hip-joint muscles.

Importance of independent measurement of width and length of lateral meniscus during preoperative sizing for meniscal allograft transplantation

BACKGROUND

Successful meniscus transplantation depends on an accurate sizing of the meniscal allograft. Although accurate sizing of the meniscal allograft is crucial during meniscus transplantation, the accuracy of meniscal measurement methods is still in debate.

PURPOSE

This study was undertaken to evaluate the relationship between the width and length of the lateral meniscus. These anatomic dimensions were also evaluated in the context of the patient's height, weight, gender, and body mass index (BMI).

STUDY DESIGN

Descriptive laboratory study.

METHODS

Ninety-one samples of fresh lateral meniscus were obtained during total knee arthroplasty. The samples were obtained carefully without injuring the meniscus itself and the bony attachment sites. For each lateral meniscus, the anatomic dimensions (width [LMW] and length [LML]) were recorded. The height, weight, gender, and BMI of the patients were also recorded. The Pearson correlation and multivariate and linear regression analysis were applied for each variable. The accuracy was defined as those measures that fell within 10% of the original size. A P value ≤ .05 was considered significant.

RESULTS

The mean LMW was 30.7 mm (standard deviation [SD] = 3.5) and 27.0 mm (SD = 2.6) for men and women, respectively. The mean LML was 33.7 mm (SD = 4.3) and 30.8 mm (SD = 2.6) for men and women, respectively. Thirty-nine samples (42.5%) showed LMW measurements within a 10% difference of LML, whereas 50 samples (55%) showed an LMW greater than a 10% difference of LML. Although there were correlations between LML with LMW in men and correlations between weight and LMW with LML in women, the accuracy for the derived linear regression formulas was 3%, 9%, and 12%, respectively.

CONCLUSION

The length cannot be predicted accurately from the width of the lateral meniscus. The height, weight, gender, and BMI failed to estimate the dimensions of the lateral meniscus. Therefore, it is essential to measure the width and length separately and match it with the allograft with other size measuring methods.

CLINICAL RELEVANCE

This study emphasizes the importance of measuring the width and length of the lateral meniscus independently during preoperative sizing for a meniscal allograft transplantation procedure. The height, weight, gender, and body mass index may not be reliable parameters for estimating the size of the meniscus.

Cross-cultural adaptation and validation of the Oxford 12-item knee score in Japanese

INTRODUCTION

With the high incidence of knee osteoarthritis (OA) in Japan, there is a strong need not only for surgical therapies, but also for validated outcome measures. For this study, we completed cross-cultural adaptation, testing and validation of the Oxford knee score (OKS) for prospective use in national and international clinical studies involving Japanese patients.

MATERIALS AND METHODS

The Japanese version of the OKS was developed according to the standard cross-cultural adaptation guidelines. For validation, the OKS was tested on 54 patients diagnosed with OA, osteonecrosis, ligament or meniscus injury. Reliability was tested using the intraclass correlation coefficient (ICC). Internal consistency or homogeneity was assessed using Cronbach's alpha. The correlation between the Japanese OKS, WOMAC and SF-36 questionnaires was used to assess construct validity.

RESULTS

No major difficulties were encountered with the translation and pre-testing stages. For reliability and validity, the Japanese OKS was completed without any missed responses by 53 (98.15%) and 52 (96.30%) patients at the first and second distribution, respectively. The total OKS showed good reliability with an ICC of 0.85. Internal consistency was strong (Cronbach's alpha = 0.90). Strong construct validity (ICC values of 0.51-0.84) was obtained against the WOMAC and SF-36 (physical functioning, role-physical, bodily pain, and social functioning subscales) scores. Notable "ceiling" effects of the OKS were reported for 11 of the 12 questionnaire items.

CONCLUSION

The Japanese OKS has proven to be a reliable and valid instrument for the self-assessment of knee pain and function in Japanese speaking patients with knee OA and other knee complaints.

Three-dimensional lower extremity alignment in the weight-bearing standing position in healthy elderly subjects

BACKGROUND

Although assessment of lower extremity alignment is important for the treatment and evaluation of diseases that present with malalignment of the lower extremity, it has generally been performed using only plain radiographs seen in two dimensions (2D). In addition, there is no consensus regarding the criteria for quantitative three-dimensional (3D) evaluation of the relative angle between the femur and tibia. The purpose of this study was to establish assessment methods and criteria for quantitatively evaluating lower extremity alignment in 3D and to obtain reference data from normal elderly subjects.

METHODS

The normal alignment of 82 limbs of 45 healthy elderly subjects (24 women, 21 men; mean age 65 years, range 60-81 years) was analyzed in 3D with regard to flexion, adduction-abduction, and rotational angle of the knee in the weight-bearing, standing position. The obtained computed tomography (CT) and biplanar computed radiography (CR) data were used to define several anatomical axes of the femur and tibia as references.

RESULTS

In the sagittal plane, the mean extension-flexion angle was significantly more recurvatum in women than in men. In the coronal plane, the mean 3D hip-knee-ankle angle was more varus by several degrees in this Japanese series than that in a Caucasian series reported previously. Regarding rotational alignment, the mean angle between the anteroposterior axis of the tibia and the transepicondylar axis of the femur in this series was slightly larger (externally rotated) than that of previously reported Japanese series examined in the supine position.

CONCLUSIONS

These data are believed to represent important references for 3D evaluation of morbid lower extremity alignment in the weight-bearing, standing position and are important for biomechanical research (e.g., 3D analyses of knee kinematics) because the relative angles between the femur and tibia are assessed three-dimensionally.

Anatomic variations between Japanese and Caucasian populations in the healthy young adult knee joint

Our objective was to characterize variations in mechanical knee alignment, tibial torsion, tibial width, and ACL laxity measurements between Japanese and Caucasian populations in the healthy, young adult knee joint. Seventy young adult subjects participated in this study, including 23 Japanese and 47 Caucasian subjects. Coronal magnetic resonance images of the hip, knee, and ankle were acquired for analysis. Japanese subjects had a significantly higher (p = 0.04) varus alignment (1.64 +/- 0.43 degrees standard error) than Caucasians (0.55 +/- 0.33 degrees), while women exhibited a more valgus alignment (0.16 +/- 0.52 degrees) than men (0.94 +/- 0.42 degrees, p = 0.04). Significant differences were found in tibial torsion and ACL laxity (p < 0.01) between ethnicities, with Japanese exhibiting lower tibial torsion (33.4 +/- 10.0 degrees) and higher ACL laxity (7.5 +/- 0.4 mm) measurements compared to Caucasians (38.9 +/- 9.5 degrees and 5.7 +/- 0.3 mm, respectively). Significant differences between genders were found in hip-knee-ankle alignment (p = 0.04), tibial width (p < 0.0001), and ACL laxity (p < 0.01) measurements. Measurements were reliable between observers and for repeated positioning. Our study provides new insight into anatomical and geometric differences in the knee joint between Japanese and Caucasians, as well as between females and males. Further consideration of these results may improve development of implants to accommodate for these differences, and understanding of characteristics leading to increased prevalence of knee OA in certain populations. The use of magnetic resonance imaging to obtain these measurements also allows soft tissue structure characterization without exposure to ionizing radiation.

Tibial torsion in non-arthritic Indian adults: a computer tomography study of 100 limbs

BACKGROUND

Knowledge of normal tibial torsion is mandatory during total knee replacement (TKR), deformity correction and fracture management of tibia. Different values of tibial torsion have been found in different races due to biological and mechanical factors. Value of normal tibial torsion in Indian limbs is not known, hence this study to determine the norm of tibial torsional value in normal Indian population.

MATERIALS AND METHODS

Computer tomography (CT) scans were performed in 100 non-arthritic limbs of 50 Indian adults (42 males, eight females; age 26-40 years). Value of tibial torsion was measured using dorsal tangent to tibial condyles proximally and bimalleolar axis distally.

RESULTS

Normal tibial torsion was found to be 21.6 +/- 7.6 (range 4.8 to 39.5) with none of the values in internal rotation. Right tibia was externally rotated by 2 degrees as compared to the left side (P 0.029). No significant difference was found in male and female subjects. Value of tibial torsion was less than in Caucasian limbs, but was comparable to Japanese limbs when studies using similar measurement technique were compared.

CONCLUSIONS

Indian limbs have less tibial torsion than Caucasian limbs but the value of tibial torsion is comparable to Japanese limbs.