Is genu varum a risk factor for the prevalence and severity of achilles tendinopathy? A cross-sectional study of Nigerian elite track and field athletes.

BACKGROUND: Achilles tendinopathy (AT) is one of the most frequently reported ankle and foot overuse injuries. Prior studies have reported altered biomechanical variables of the lower limb as risk factors for the prevalence and severity of AT in athletes, especially in Caucasians, but there are few reports on African elite athletes. Because it is established that anthropometric and biomechanical values vary with racial disposition, this study was designed to investigate the association between selected physical and biomechanical variables of the lower limb and the prevalence and severity of AT in Nigerian elite track and field athletes. SUBJECTS AND METHODS: Eighty-five elite Nigerian track and field athletes participated in this cross-sectional study. Biomechanical variables of Q-angle, tibial torsion, limb-length discrepancy (LLD) and foot posture index (FPI) were evaluated using standard procedures. The presence of AT was confirmed with ultrasonography and clinical assessments, whereas the severity was evaluated with VISA-A questionnaire. Inferential statistics of Chi-square was used to determine the association between prevalence of AT and the biomechanical variables. RESULTS: The prevalence of AT was 15.3%, made up of participants who tested positive to both clinical test and ultrasound scan. There was no significant association between AT and LLD, tibial torsion and FPI. Most of the participants with AT had genu varum, which was significantly associated with both the prevalence and severity of AT. CONCLUSION: It was concluded that genu varum had a significant association with both the prevalence and severity of AT in elite Nigerian track and field athletes.

The Prevalence of Genu Varum and Genu Valgum in Overweight and Obese Patients: Assessing the Relationship between Body Mass Index and Knee Angular Deformities.

BACKGROUND: Recent studies have shown evidence of a relationship between overweight and obesity with skeletal abnormalities, especially angular knee disorders. AIM OF THE STUDY: To reveal causal relationship between obesity and skeletal abnormalities. METHODS: This study was performed on 280 overweight or obese patients (with BMI > 25kg/m2) who referred to Rasoul Akram hospital in Tehran between 2017 and 2018. Several non-radiographic methods including measuring Q angle, inter-malleoli distance and distance between two knees were used to determine genu varum and genu valgum.  BMI was also calculated by dividing the weight by the square of the height. RESULTS: The prevalence of genu varumand genu valgum was 8.6% and 10.0% respectively. There was a significant adverse correlation between the Q angle and BMI. The mean BMI in patients with and without genu varum was 39.07 ± 6.41 kg/m2 and 42.1 ± 2.26 kg/m2, respectively, which was significantly lower in the genuvarum group (P = 0.008). Also, the mean BMI in patients with and without genu valgum was 43.39 ± 3.33 kg/m2 and 41.58 ± 4.61  kg/m2, respectively, which was significantly higher in the genuvalgum group (P = 0.044). Also, there was a direct correlation between BMI of patients with inter-malleoli distance and inverse correlation between BMI and two knees distance. CONCLUSION: There is a strong and significant relationship between incidence of obesity and genu valgum; therefore, the prevalence of this deformity in obese individuals is predictable. Also, the lower incidence of genu varum in obese people is predictable in our society.

In Asian women undergoing total knee arthroplasty, lower leg morphology in those with rheumatoid arthritis differed from those with osteoarthritis.

Objectives: This retrospective, single-center study aimed to compare leg morphology between patients with rheumatoid arthritis (RA) and those with osteoarthritis (OA) undergoing total knee arthroplasty (TKA).Methods: We enrolled 70 RA and 327 OA female patients undergoing TKA. Hip-knee-ankle angle (HKA), femorotibial angle (FTA), valgus correction angle (VCA), and femoral/tibial bowing were measured using full-length radiographs. Femoral bowing of more than 3° or tibial bowing more than 2°, either laterally or medially, was considered substantial. Distribution of these results and the incidence of substantial bowing in RA and OA were compared.Results: HKA, FTA, and VCA were significantly smaller in RA than those in OA. Femoral bowing was significantly smaller in RA (mean angle: 0.04° ± 3.1°) than that in OA (mean angle: 2.1° ± 3.6°) (p < .05). In almost half of the patients with RA (48.6%), femoral bowing occurred medially, whereas femoral bowing occurred laterally in approximately three quarters of OA patients (73.1%). Tibial bowing did not differ. The incidence of substantial femoral bowing was significantly lower in RA (27.1%) than that in OA (43.0%) (p < .05).Conclusion: RA patients undergoing TKA had different leg morphology than OA patients. These findings have implications for surgical planning.

Physiologic Leg Bowing is not a Physiologic Condition but Instead is Associated with Vitamin D Disorders in Toddlers.

When children around 2-year-old show leg bowing without lower-limb radiographic abnormalities for rickets, the leg bowing is classified as "physiologic" genu varum without conducting a blood test. However, it has recently been suggested that toddlers who are diagnosed with physiologic genu varum may in fact have some form of bone metabolic disorder. In this 1:2 case-control study, blood samples were obtained from 33 toddlers with genu varum without radiographic abnormalities for rickets and 66 age- and gender-matched healthy children. Serum alkaline phosphatase (sALP), intact parathyroid hormone (siPTH), 25-hydroxy vitamin D [s25(OH)D], calcium (sCa), and inorganic phosphate (sP) were measured. s25(OH)D of the subjects with genu varum (24.8 ng/ml) were significantly lower than those of the control (33.6 ng/ml) (p < 0.001). The frequency of vitamin D insufficiency/deficiency (< 20 ng/ml) of the subjects with genu varum (39%) was significantly higher than that in the control (14%) (p = 0.004) (odds ratio by vitamin D insufficiency/deficiency: 4.1 [1.5-11.1, p = 0.004]). sCa in subjects with genu varum (10.2 ng/ml) were significantly higher than in control (9.8 ng/ml) (p < 0.001), as were sALP (1057 IU/l) and siPTH (28.4 pg/ml) (740 IU/l and 8.8 pg/ml in control, respectively; p < 0.001). siPTH levels were associated with s25(OH)D levels in subjects with genu varum (r = - 0.57, p < 0.001), while no association was observed in the control (r = 0.11, p = 0.36). Genu varum without radiographic abnormalities of rickets was associated with both vitamin D and bone-metabolic disorders in toddlers, indicating that physiologic genu varum is not a physiologic condition in toddlers.

Prevalence of musculoskeletal normal variations of the lower limbs in pediatric orthopedic clinic.

OBJECTIVES: To determine the rate of pediatric orthopedic clinic visits attributable to normal musculoskeletal (MSK) variations in children less than 12 years of age; to characterize the etiology and to characterize the etiology and management plan in this group in an attempt to identify areas that could be improved in pediatric orthopedic clinical practice. METHODS: The study was a retrospective evaluation of 2,321 consecutive patients who visited a private pediatric orthopedic specialty clinic in Jeddah, Saudi Arabia between 2011-2016. All consultations were recorded in accordance with the standard protocol  via data record form. RESULTS: We identified 764 (32.9%) patients with normal variation of the lower limbs, age birth to 12 years old. No significant association between gender and normal variation was noticed. The following types of normal variation were registered: 189 (24.7 %) genu varus or valgus, 257 (33.6%) in-toe gait, and 318 (41.6%) flexible flat foot. Seven hundred and thirty-seven (96.5%) cases were normal variations, while only 27 cases (3.5%) were deemed pathological and required further treatment. CONCLUSION: Normal variations represent the most common complaint in pediatric orthopedic private practice. Inappropriate referrals, useless follow-up visits, and excessive investigations were a common practice, overloading the health care system. None of the previous efforts made any notable improvement.

Tibial bowing and tibial component placement in primary total knee arthroplasty in valgus knees: Are we overlooking?

PURPOSE: Tibial bowing in valgus knees with arthritis can lead to component malplacement during total knee arthroplasty (TKA). Incidence of valgus knees with medial tibial bowing, its effect on tibial component placement during primary TKA and methods to improve accuracy of the component placement were studied. METHODS: Full-length weight-bearing alignment radiograph was taken in 117 patients (149 knees) with valgus deformity undergoing TKA. In these cases, the proximal tibial reference for extramedullary jig placement was planned preoperatively with reference to the tibial spines and classified as four zones. RESULTS: The mean preoperative hip-knee-ankle (HKA) angle was 192.9° (180.3-234.5°). Bowing >3° was considered significant (p < 0.001) and at this level of bowing, the proximal tibial reference was shifted from centre to medial. Tibial bowing <3° was considered straight and >3° as tibia valga. Tibia was bowed in 70 knees (46.97%). Severity of valgus deformity had strong positive correlation with the tibia valga (p < 0.001). The post-operative medial proximal tibial angle (MPTA) and HKA angle were 91.63° (87.9-95.7°) and 182.6° (178.1-189.7°), respectively. The mean MPTA and post-operative HKA angle in bowed and straight tibiae were 90.35° versus 89.78° (p = 0.547) and 181.5° versus 180.7° (p = 0.5716), respectively, and the difference was not statistically significant. CONCLUSION: Medial tibial bowing is very common in valgus knees. Tibia valga has a strong positive correlation with the severity of valgus deformity. Accurate tibial component placement can be achieved with a medialized reference point for extramedullary tibial cutting jig in knees with significant tibia valga. The study has been registered in clinical trials registry - India (CTRI/2018/03/012283).

Clinical Knee Alignment among Adolescents and Association with Body Mass Index: A Large Prevalence Study.

BACKGROUND: Children and adolescents are commonly referred to an orthopedic surgeon to assess knee malalignment. OBJECTIVES: To assess the prevalence of genu varum and valgum among adolescents, and to identify correlates of these conditions. METHODS: A medical database of 47,588 candidates for military service presenting to the northern recruitment center during an 11 year period was analyzed to identify clinical knee alignment. Based on the standing skin surface intercondylar distance (ICD) or intermalleolar distance (IMD), the prevalence rates of genu varum (ICD ≥ 3 cm) and genu valgum (IMD ≥ 4 cm) were calculated. The association of gender, body mass index (BMI), and place of residence to knee alignment was studied. RESULTS: The rates of genu varum and valgum were 11.4% (5427) and 5.6% (2639), respectively. Genu varum was significantly more prevalent among males than females (16.2% vs. 4.4%, P < 0.001). It was also more prevalent among underweight subjects and less prevalent among overweight and obese subjects (P < 0.001). Genu valgum was significantly more prevalent among females than males (9.4% vs. 2.9%) and in overweight and obese subjects compared to those with normal BMI, while less prevalent in underweight subjects (P < 0.001). Multivariate analysis revealed that genu varum was independently positively associated with male gender, underweight, and living in a rural area. Genu valgum was independently positively associated with female gender, overweight, and obesity. CONCLUSIONS: This study establishes a modern benchmark for the cutoff and prevalence of genu varum and valgum as well as associations with gender and BMI.

Varus Thrust and Incident and Progressive Knee Osteoarthritis.

OBJECTIVE: To determine if varus thrust, a bowing out of the knee during gait (i.e., the first appearance or worsening of varus alignment during stance), is associated with incident and progressive knee osteoarthritis (OA), we undertook an Osteoarthritis Initiative ancillary study. We further considered hypothesized associations adjusted for static alignment, anticipating some attenuation. METHODS: Gait was observed for the presence of thrust by 1 of 2-3 examiners per study site at 4 sites. In eligible knees, incident OA was defined as subsequent incident Kellgren/Lawrence grade ≥2, whole- and partial-grade medial joint space narrowing (JSN), and annualized loss of joint space width (JSW); progression was defined as medial JSN and JSW loss. Outcome measures were assessed for up to 7 years of follow-up. Analyses were knee-level, using multivariable logistic and linear regression with generalized estimating equations to account for between-limb correlation. RESULTS: The incident OA sample included 4,187 knees (2,610 persons); the progression sample included 3,421 knees (2,284 persons). In knees with OA, thrust was associated with progression as assessed by each outcome measure, with adjustment for age, sex, body mass index, and pain on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale. In knees without OA, varus thrust was not associated with incident OA or other outcomes. After adjustment for alignment, the thrust-progression association was attenuated, but an independent association persisted for partial-grade JSN and JSW loss outcome models. WOMAC pain and alignment were consistently associated with all outcome measures. Within the stratum of varus knees, thrust was associated with an increased risk of progression. CONCLUSION: Varus thrust visualized during gait is associated with knee OA progression and should be a target of intervention development.

[Coincidence and Therapy of Dysalignments and Degenerative Knee Cartilage Lesions. Results from the German CartilageRegistry DGOU]. / Koinzidenz und Therapie von Beinachsdeviationen bei degenerativen Knorpelschäden des Kniegelenks. Ergebnisse aus dem Deutschen KnorpelRegister DGOU.

Purpose This multicenter study was aimed to evaluate the coincidence of degenerative knee cartilage lesions with a varus or valgus dysalignment. Furthermore, the frequency of the combined surgery of cartilage treatments and corrective osteotomies are determined. Material and Methods A total of 1778 patients were included in the German CartilageRegistry (deadline 01.08.2016). In 90.6% of patients, the surgeon calculated the alignment by clinical observation. Varus or valgus conditions were measured radiologically in only 56.0%. This study describes patients who underwent treatment of degenerative cartilage lesions with a complete (clinical and radiological) determination of the alignment. Results The mean mechanical tibia-femur angle (Paley) (mTFA) in clinically neutral extremities was 0.2° (SD 0.6; 0 - 5), in varus cases 5,0° (SD 3.2; 0 - 15), and - 4.7° (SD - 4.0; - 15 - 0) in valgus cases. Varus dysalignment was significantly associated with cartilage lesions in the medial compartment. Valgus dysalignment more frequently occurred in knees with lateral cartilage lesions. Independently of the surgeon's choice of the method of cartilage surgery, in 72.4% of all valgus deformities a corrective osteotomy was performed. Valgus dysalignment was corrected in 50%. Conclusions In about a quarter of all cases, cartilage lesions are associated with a varus (18.9%) or valgus (4.2%) dysalignment. In a number of cases, the treatment of cartilage lesions should include the addressing of these axial deviations. Still the efficacy of this procedure regarding prognosis and clinical outcome is unclear.

Lower extremity and spine characteristics in young dancers with and without patellofemoral pain.

Very little is known about patellofemoral pain syndrome (PPFS) among young dancers. Understanding the mechanism of the injury and implementing a preventative programme are important in order to minimize the risk of PFPS. The aim of the current study is to determine the extent to which factors such as lower extremity and back characteristics are common among dancers with PFPS. The study population included 271 dancers with PFPS and 271 non-injured dancers, aged 10-16 years. All dancers were screened for morphometric profile, dance discipline (h/week), anatomical anomalies (present/absent of scoliosis, genu valgus/varum, etc.), and joint range of motion (measured by goniometer at the hip, knee, ankle, foot, and spinal joints). The predicting factors for PFPS among young dancers (10-11 years old) were: hyper hip abduction (OR = 0.906) and lower back and hamstring flexibility (OR = 3.542); for adolescent dancers (12-14 years old): hyper ankle dorsiflexion (OR = 0.888), hind foot-varum (OR = 0.260), and mobility of patella (OR = 2.666); and, for pre-mature dancers (15-16 years old): scoliosis (OR = 5.209), limited ankle plantar-flexion (OR = 1.060), and limited hip internal rotation (OR = 1.063). In conclusion, extrinsic and intrinsic parameters predisposing the dancers to knee injuries should be identified by screening in early stages of dance classes.

How does lower leg alignment differ between soccer players, other athletes, and non-athletic controls?

PURPOSE: The influence of type and intensity of sports during growth on knee alignment was investigated. The second aim was to ascertain whether the distal femur or proximal tibia contribute most to knee alignment. Also, the influence of field position and leg dominancy on knee alignment in soccer players was audited. METHODS: Standardized full-leg standing digital radiographs were obtained from 100 males and 100 females on which 8 different alignment parameters were measured. Participants were questioned on their sports activities during different stages of growth. Sports activities were graded according to the Tegner score. RESULTS: The mean (±SD) hip-knee-ankle angle (HKA) was significantly lower (p < 0.001) in high-activity male athletes (-2.8° ± 2.4°) than in low-activity male athletes (-0.9° ± 1.9°). No differences in HKA were observed between different activity levels in females. Males who practiced soccer between 10-12 years and 15-17 years had, in turn, a lower HKA than athletes practicing other high-activity sports in these age categories (mean difference ≥1.2°, p ≤ 0.046). The most contributing factor for the varus alignment in male soccer players was a lower medial proximal tibial angle (MPTA). CONCLUSION: High-activity sports participation during youth is associated with varus alignment at the end of growth in males. The most pronounced bowlegs were observed in male soccer players, and this was primarily determined by the proximal tibia. Adjustments in loads applied to the knees during skeletal growth in males might prevent the development of varus alignment and associated pathology, but further studies are required. LEVEL OF EVIDENCE: Diagnostic study, Level III.

Breaking the Law of Valgus: the surprising and unexplained prevalence of medial patellofemoral cartilage damage.

OBJECTIVES: To compare the prevalence of medial and lateral patellofemoral (PF) cartilage damage in three large osteoarthritis (OA) studies and determine the relationship of this damage to varus, neutral and valgus knee alignment. METHODS: In the Boston OA of the Knee, Framingham OA and Multicenter OA studies, MRIs were read for cartilage morphology at the medial and lateral patella and trochlea femoris using Whole-Organ MRI Scores (WORMS). WORMS scores ≥2 (any cartilage defect), ≥3 (areas of partial thickness loss), ≥4 (diffuse partial thickness loss) and ≥5 (extensive full thickness loss) were all variously considered as thresholds to identify damage that may indicate OA. Full-limb radiographs were measured for mechanical alignment, and varus (<-2°), neutral (-2° to 2°) and valgus (>2°) knees were identified. RESULTS: The prevalence of medial PF cartilage damage exceeded that of lateral damage in all three studies and according to nearly every threshold. Only among severely involved knees (WORMS ≥4 or ≥5) did the prevalence of lateral PF cartilage damage approximate that of medial damage. The high prevalence of medial PF damage persisted in all strata of knee alignment. Even among knees with valgus alignment, the prevalence of lateral PF cartilage damage equalled or surpassed that of medial PF damage only when the threshold was specific to severely involved knees. CONCLUSIONS: Medial PF cartilage damage is at least as prevalent within these older adult populations as lateral PF cartilage damage.

[Evaluation of the varus-valgus knee in a group of calabrian children]. / Valutazione del varismo-valgismo del ginocchio in un gruppo di bambini calabresi.

INTRODUCTION: In the early years of life, the angular deviation of knee causes anxiety in parents and alert to paediatricians. The problem is often an expression of physiological development of the lower limbs and correction occurs spontaneously. A small number of children has a true pathology, which can lead to functional problems, modification of the knee's axis and muscular-skeletal disorders. We analyzed the prevalence of pathological forms of varus-valgus knee and their association with lower limb dysmetria and scoliotic attitude. MATERIALS AND METHODS: We evaluated radiographies of the lower limbs of 60 calabrian children; we analyzed the mechanical axis of knee and articular spacing angles. We evaluated the X-ray of the spine with study of Cobb's angle and the gradient of the femoral head. RESULTS: 61.6% of children had a deflection angle of the knee: 6.7% physiological varus and 28.3% physiological valgus, 8.3% pathological varus and 18.3% pathological valgus. Mechanical axis deviation was: +15.6 degrees with articular spacing angle of about +2.4 degrees in pathological varus and +1.95 degrees with articular spacing angle of about -2.09 degrees in pathological valgus. 15% of children had pathological deviation and femoral head dysmetria (7.7 mm). 10% of children had association between pathological valgus/varus knee, dysmetria and scoliotic attitude ( 8.3% sacral-lumbar scoliotic attitude with Cobb's angle <20 degrees ). CONCLUSIONS: Without alarm we must pay attention to varus/valgus knee, because probably it will be a physiological deviation. In the pathological condition, it is important to consider the association with the limbs dysmetria that can lead to irreversible scoliotic postural deviation, if ignored for a long time. Unlikely early diagnosis and a subsequent correction of these defects could assurance a good development of skeletal structure.

A prática do futebol acentua os graus de Geno Varo / Does soccer practice stress the degrees of genu varo

Estudos têm mostrado uma varização progressiva entre os períodos de infância e adolescência. Variáveis como idade, peso, ingestão hormonal e vitamínica, ambiente e o treinamento de futebol podem interferir no alinhamento do joelho. OBJETIVOS: A) Comparar o alinhamento do joelho de praticantes e não praticantes de futebol; e B) Determinar associações entre este alinhamento com variáveis antropométricas e neuromotoras da aptidão física. MÉTODOS: A distância intercondilar (DIC) e a intermaleolar (DIM) foram mensuradas em centímetros em 128 adolescentes com idades entre 14 a 17 anos, dentre os quais 65 eram praticantes de futebol e 63 não eram praticantes de tal modalidade. As variáveis antropométricas mensuradas foram peso e estatura, enquanto as neuromotoras inclusas foram agilidade e velocidade. RESULTADOS: Os praticantes de futebol apresentaram graus mais acentuados de joelho varo do que os não jogadores de futebol em todas as idade; entretanto, apenas nos 14 e 17 anos e no grupo total (todas idade juntas) essa diferença foi estatisticamente significativa (p < 0,05). Geno valgo (DIM) tende a ser menor nos praticantes de futebol em todas as idade quando comparados com os não jogadores de futebol; entretanto, tal diferença foi estatisticamente significativa (p < 0,05) apenas nos 17 anos de idade e no grupo total. A DIC nos praticantes de futebol apresentou correlação (p < 0,05) com a agilidade (r = -0,27) e o peso (r = -0,27), enquanto a DIM apresentou correlação (p < 0,05) com o peso (r = 0,26). CONCLUSÃO: Praticantes de futebol mostram um alinhamento do joelho mais acentuado a favor do varismo do que os não praticantes de futebol. Houve associação significativa entre os graus de geno varo e valgo com o peso e a agilidade; nesse sentido, sugere-se mais estudos para explicar essa interessante relação. Os achados do presente estudo suportam a hipótese de que o futebol acentua os graus de geno varo e/ou os sujeitos são selecionados naturalmente para tal prática.

Studies have shown a progressive variation between the childhood and adolescence periods. Variables such as age, weight, vitamin/hormone intake, the environment and soccer training may interfere in the knee alignment. OBJECTIVE: a- to compare the knee alignment in soccer and non-soccer practitioners, and b- to determine associations between this alignment and anthropometric and neuromotor variables. METHODS: The intercondylar (IC) and intermalleolar (IM) distances were measured in centimeters in 128 male aged from 14-17 years, soccer practitioners (n=65) and non-practitioners (n=63). The anthropometric variables measured were: body weight and height, whereas the neuromotor variables included agility and speed. RESULTS: Soccer players revealed a greater degree of genu varum (IC) than non-soccer players in all ages, but just in 14, 17 years-old and total group (all ages together) these differences were statistically significant (p< .05). Genu valgum (IM) tended to be less remarkable in soccer players than in non-soccer players in all ages; however, significant differences were observed only in 17 years and total group (p< .05). The IC distances in soccer players correlated (p< .05) with agility (r= .-27), weight (r= .-27); while IM distances correlated (p< .05) with weight(r=.26). CONCLUSION: Soccer players showed more remarkable genu varum than the non-soccer players. There was a significant association between degrees of varus and valgum with body weight and agility. Such fact deserves further investigation in order to explain this interesting correlation. Present findings support the hypothesis that soccer leads to greater varus and/or this sport naturally selects subjects with a certain degree of varus.

Variations in varus/valgus and internal/external rotational knee laxity and stiffness across the menstrual cycle.

Cyclic variations in genu recurvatum (GR), general joint laxity (GJL), varus-valgus (VV), and internal-external (IER) rotational laxities and stiffnesses were examined in 64 females and 43 males at two time points during the females' menstrual cycle [days of minimum (T1) and maximum (T2) anterior knee laxity (AKL)]. Cyclic increases in AKL (9.5%), GR (37.5%), and GJL (13.6%) were observed in females but not males from T1 to T2 (p < 0.001). Cyclic increases in VV and IER laxity were negligible (1.5-3.2%, p > 0.320). Females compared to males had lower overall VV stiffness at T2 (F 37%

Predicting the effect of tray malalignment on risk for bone damage and implant subsidence after total knee arthroplasty.

Tibial tray malalignment has been associated with increased subsidence and failure. We constructed a finite element model of knee arthroplasty to determine the biomechanical factors involved in increasing the risk of subsidence with malalignment. Four fresh-frozen human knees were implanted with a tibial tray and subjected to forces representative of walking for up to 100,000 cycles. Cyclic displacement was measured between the tray and proximal tibia. The vertical load was shifted medially to generate a load distribution ratio of 55:45 (medial/lateral) to represent neutral alignment or 75:25 to represent varus alignment. Subjected specific geometry and material properties were obtained from qCT scans of tibia to construct a finite element model. The tray was subjected to a single load cycle representing experimental conditions. Tray displacement computed by the model matched that measured experimentally. Forces representing varus tray alignment generated greater strains in the proximal tibia and a greater volume of bone was subjected to strains higher than the fatigue threshold. Local compressive strains directly correlated with experimental subsidence and failure. Our results indicate that failure after tray malalignment is likely due to fatigue damage to the proximal tibia rather than shear across the implant-bone interface or failure of the cement mantle.

High prevalence of genu varum/valgum in European children with low vitamin D status and insufficient dairy products/calcium intakes.

OBJECTIVE: The prevalence of lower limb deformities physiologically decreases after 5 years of age. It remains high in some tropical and subtropical regions where it has been associated with severe vitamin D deficiency, low calcium/milk intakes, malnutrition, and/or fluoride overexposure. Very little data is available in apparently healthy Caucasian children and adolescents. DESIGN: We evaluated the prevalence of genu varum/valgum and other clinical symptoms, and assessed vitamin D status and markers of calcium metabolism in 226 apparently healthy European full-time boarders (7-16 years) seen during winter-spring and fed a cereal-based diet with little access to meat, milk, and dairy products. A cohort of 71 white children and adolescents hospitalized for acute illness served as age-matched controls. RESULTS: Association studies showed a high prevalence of lower limb deformities (36%) and higher alkaline phosphate activities in the 21% of children and adolescent full-time boarders with serum 25-(OH)D levels ≤ 30 nmol/l, and low serum calcium in the 74% of boarders with 25-(OH)D levels ≤ 50 nmol/l, compared with boarders with higher vitamin D status. No such anomalies were found in the control cohort despite lower serum 25-(OH)D levels. CONCLUSIONS: Low 25-(OH)D levels, at least during winter-spring, combined with additional risk factors such as very low calcium/milk intakes and possibly digestive disorders, are associated with an increased risk of genu varum/valgum in European children and adolescents. Thus, dietary fortification, or supplementation with vitamin D, may be recommended, at least during the winter, to European children and adolescents with either none or insufficient calcium/dairy product intakes.

Varus and valgus alignment and incident and progressive knee osteoarthritis.

OBJECTIVE: Varus and valgus alignment increase medial and lateral tibiofemoral load. Alignment was associated with tibiofemoral osteoarthritis progression in previous studies; an effect on incident osteoarthritis risk is less certain. This study tested whether alignment influences the risk of incident and progressive radiographic tibiofemoral osteoarthritis. METHODS: In an observational, longitudinal study of the Multicenter Osteoarthritis Study cohort, full-limb x-rays to measure alignment were acquired at baseline and knee x-rays were acquired at baseline and knee x-rays at baseline and 30 months. Varus alignment was defined as ≤178° and valgus ≥182°. Using logistic regression and generalised estimating equations, the associations of baseline alignment and incident osteoarthritis at 30 months (in knees without baseline osteoarthritis) and alignment and osteoarthritis progression (in knees with osteoarthritis) were examined, adjusting. For age, gender, body mass index, injury, laxity and strength, with neutral knees as referent. RESULTS: 2958 knees (1752 participants) were without osteoarthritis at baseline. Varus (adjusted OR 1.49, 95% CI 1.06 to 2.10) but not valgus alignment was associated with incident osteoarthritis. 1307 knees (950 participants) had osteoarthritis at baseline. Varus alignment was associated with a greater risk of medial osteoarthritis progression (adjusted OR 3.59, 95% CI 2.62 to 4.92) and a reduced risk of lateral progression, and valgus with a greater risk of lateral progression (adjusted OR 4.85, 95% CI 3.17 to 7.42) and a reduced risk of medial progression. CONCLUSION: Varus but not valgus alignment increased the risk of incident tibiofemoral osteoarthritis. In knees with osteoarthritis, varus and valgus alignment each increased the risk of progression in the biomechanically stressed compartment.