Pulkesh Singh

Effect of thermal stratification on double-diffusive natural convection in a vertical porous enclosure

A numerical study on combined heat and mass transfer by natural convection adjacent to a vertical surface in a thermally stratified fluid saturated square porous enclosure is reported. The Galerkin finite element method on a graded grid system has been employed in the numerical computations. When thermal and species diffusion coefficients are equal, increasing levels of thermal stratification significantly influence both the aiding and opposing flow structures and their concomitant temperature fields. For unequal species and thermal diffusion coefficients changes in the concentration field structure are seen to be more prominent. The Nusselt (Nu) and Sherwood (Sh) number data have been presented for various values of Lewis number (Le), buoyancy ratio (B), and Rayleigh number ( Ra ) at various levels of stratification (S).

Epidemiology of knee osteoarthritis in India and related factors

Background: Among the chronic rheumatic diseases, hip and knee osteoarthritis (OA) is the most prevalent and is a leading cause of pain and disability in most countries worldwide. Its prevalence increases with age and generally affects women more frequently than men. OA is strongly associated with aging and heavy physical occupational activity, a required livelihood for many people living in rural communities in developing countries. Determining region-specific OA prevalence and risk factor profiles will provide important information for planning future cost effective preventive strategies and health care services. Materials and Methods: The study was a community based cross sectional study to find out the prevalence of primary knee OA in India which has a population of 1.252 billion. The study was done across five sites in India. Each site was further divided into big city, small city, town, and village. The total sample size was 5000 subjects. Tools consisted of a structured questionnaire and plain skiagrams for confirmation of OA. Diagnosis was done using Kellgren and Lawrence scale for osteoarthritis. Results: Overall prevalence of knee OA was found to be 28.7%. The associated factors were found to be female gender (prevalence of 31.6%) (P = 0.007), obesity (P = 0.04), age (P = 0.001) and sedentary work (P = 0.001). Conclusions: There is scarcity of studies done in India which has varied socio geographical background and communities. We conducted this study for analyzing the current prevalence of OA in different locations. This study has evidenced a large percentage of population as borderline OA; therefore, it depends mainly on the prevention of modifiable risk factors to preserve at ease movement in elderly population through awareness programs.

Fixation with cancellous screws and fibular strut grafts for neglected femoral neck fractures

Purpose. To review the outcomes of fixation with cancellous screws and fibular strut grafts for neglected femoral neck fractures. Methods. 44 men and 28 women aged 17 to 50 years with neglected femoral neck fractures of the subcapital (n=12), transcervical (n=57), or basal (n=3) types underwent closed (n=39) or open (n=33) reduction and fixation with a single cancellous screw with double fibular strut grafts (n=24) or fixation with double cancellous screws with a single fibular strut graft (n=48). The mean time from injury to surgery was 10 weeks; the delay was 22 to 35 days in 43 patients and >35 days in 29 patients. Double fibular strut grafts were used for 18 patients with longer delay and resorption of the femoral neck, and 18 patients with posterior comminution of the femoral neck. The outcome was assessed using the Harris hip score. Results. Patients were followed up for a mean of 3 years. The time to bone union was 3 to 4 months in 48 patients, 4 to 5 months in 15, and 5 to 6 months in 5; nonunion was noted in 4 patients. In 18 patients with resorption of the femoral neck, bone union took a longer time. The Harris hip score was excellent (90–100) in 30 patients, good (80–89) in 20, fair (70–79) in 15, and poor (±70) in 7. Of the latter, 4 had nonunion and 3 developed avascular necrosis of the femoral head; they had persistent pain and restriction of hip joint movement. Conclusion. Fixation with cancellous screws and fibular strut grafts for neglected femoral neck fractures is cost-effective and technically less demanding, and associated with good outcomes.

Flatfoot in Indian population.

Purpose. To compare outcomes of different conservative treatments for flatfoot using the foot print index and valgus index. Methods. 150 symptomatic flatfoot patients and 50 controls (without any flatfoot or lower limb deformity) aged older than 8 years were evaluated. The diagnosis was based on pain during walking a distance, the great toe extension test, the valgus index, the foot print index (FPI), as well as eversion/inversion and dorsiflexion at the ankle. The patients were unequally randomised into 4 treatment groups: (1) foot exercises (n=60), (2) use of the Thomas crooked and elongated heel with or without arch support (n=45), (3) use of the Rose Schwartz insoles (n=18), and (4) foot exercises combined with both footwear modifications (n=27). Results. Of the 150 symptomatic flatfoot patients, 96 had severe flatfoot (FPI, >75) and 54 had incipient flatfoot (FPI, 45–74). The great toe extension test was positive in all 50 controls and 144 patients, and negative in 6 patients (p=0.1734, one-tailed test), which yielded a sensitivity of 96% and a positive predictive value of 74%. Symptoms correlated with the FPI (Chi squared=9.7, p=0.0213). Combining foot exercises and foot wear modifications achieved best outcome in terms of pain relief, gait improvement, and decrease in the FPI and valgus index. Conclusion. The great toe extension test was the best screening tool. The FPI was a good tool for diagnosing and grading of flatfoot and evaluating treatment progress. Combining foot exercises and foot wear modifications achieved the best outcome.

Periprosthetic Femoral Fracture With Broken Implant Insitu: - A Treatment Prospect.

Introduction: Fractures involving bones containing a component of a prosthetic joint are becoming more common. The causation is multifactorial but most of these injuries are associated with trivial trauma. The options available for operative management of these fractures include internal fixation of the fracture alone, fixation of the fracture with revision of the prosthesis, and reconstruction of proximal femur with either modified impaction bone grafting or proximal femoral replacement. Case Report: We present here a case of periprosthetic fracture Vancouver type B1 with a broken cemented bipolar prosthesis insitu, in which the broken implant was firmly fixed in the proximal fragment and could not be removed following which the whole of the proximal fragment along with the broken implant was removed and replaced by a customized steel long stem cemented mega prosthesis. Conclusion: This case is being presented on account of its unusual presentation and fracture pattern. A broken prosthesis along with a periprosthetic fracture is not a common incident. Thus the treatment had to be individualized. Since the prosthesis was well fixed, its broken stem could not be removed from the proximal fragment and so the whole of the proximal fragment along with stem was removed and replaced with a long stem custom made bipolar prosthesis.

Entropy of Mixing of Compound Forming Liquid Binary Alloys Using Flory's Formula

Abstract We demonstrate how the formula we proposed recently for the effective volume can be applied to improve Florys formula so that the entropy of mixing of liquid binary alloys can be determined theoretically with good accuracy. The results are distinctly better than in the hard sphere system for compound forming alloys.

Complete Traumatic Separation of Proximal Femoral Epiphysis in A 2 Year Old Child

Introduction: Hip fractures are very common in adults, but are rare in children, comprising less than 1% of all pediatric fractures. Separation of the proximal femoral epiphysis can occur in a child with a traumatic hip dislocation and an open epiphysis. Regardless of the mechanism of proximal femoral epiphyseal separation, the prognosis is poor secondary to the development of osteonecrosis. Case Report: Here we are reporting a case of complete separation of the proximal epiphysis of the femur in a 2 year old female child. She was treated by open reduction and internal fixation by a single k-wire of proximal femoral epiphysis. Regular follow up showed fusion of proximal femoral epiphysis at about 3 months of post operative period. After 8 months of follow up she can stand and walk without support. Long term outcome is awaited. Conclusion: Traumatic separation of the proximal femoral epiphysis is a rare but devastating injury because osteonecrosis occurs in most cases. In our study we found fusion of the proximal femoral epiphysis to the neck after 3 months of postoperative period. But to comment upon the final outcome a long follow up is awaited.

Primary plating osteosynthesis in open fractures

Introduction: The management of open fractures poses one of the greatest challenges to orthopaedic surgeons because it not only requires management of a contaminated soft tissue injury involving skin, muscles and neurovascular structures but also treatment of underlying fracture which is also contaminated. Primary internal fixation if done can solve many problems. With the use of internal fixation the fracture remain in good position so that soft tissue injuries can be handled easily and effectively. Materials and Methods: Present study was carried out in 12 skeletally mature patients. All open fractures of upper and lower extremities presenting within 12 hours of trauma were included in study. The wound was then cleaned and injured part was then splinted so that movement of fracture fragment causing further damage could be prevented. In operation theatre wound debridement was done before internal fixation under aseptic conditions. Results: Regarding soft tissue healing all the cases of grade I showed either good (66.67%) or fair (33.33%) results. Out of 4 cases of upper limb, 2 cases (50%) of grade I united within 4 months. One case of grade III of upper limb united in 6 months. Out of 8 cases of lower limb, 3 cases (37.5%) united within 5 months and 4 cases (50%) united within 6 months. One case of grade III fracture tibia showed delayed union, bone grafting was done in this case. Conclusion: We conclude from the study that the judicious selection of cases, skillful management of the injured limb and early rehabilitation is the key for compound fractures.

Role of proximal femoral nailing in fracture neck of femur

Background: The present study was done (a) to assess the role of proximal femoral nailing in the femoral neck fractures. (b) To assess the effect of early weight bearing after stabilization with proximal femoral nail. (c) To assess the incidence of complications in femoral neck fractures treated by proximal femoral nail. Materials and Methods: The present prospective study was conducted in the department of Orthopedics, of this institute from September 2007 to August 2009, which is a tertiary care center. A total of 22 patients of fracture neck of femur were included in the study. Only patients with basal and transcervical type of fractures with viable femoral head were included in the study. Patients with subcapital type of fracture were excluded from the study. All the patients were followed regularly for a period of two years. These fractures were fixed with proximal femoral nail. The final outcome measurement was done according to Harris hip scoring (HHS) method of functional assessment. Results: Sixty three percent of cases of our study presented with non union and 37% showed osseous union of which three were of basal type and five were of transcervical type. Out of the 22 patients assessed according to Harris hip score only 27.24% cases showed good result whereas 63.56% cases showed poor results. Results based on the anatomical type of fracture showed basal type of fractures with good results of union while 73.68% of the transcervical type of fractures showed poor results. Fair results were seen in 10.25% while only 15.26% of the patients showed good results in transcervical type of fractures. Good results obtained in transcervical type of fracture were the ones associated with subtrochanteric fracture femur. The purely transcervical type of fracture showed fair results in only two patients while the rest showed non union. Conclusions: After conduction of this study on results of the treatment of intracapsular fracture neck of femur by proximal femoral nailing we conclude that (A) proximal femoral nail is useful in basal type of fracture and in those types of transcervical fractures which are associated with ipsilateral subtrochanteric fracture. (B) Proximal femoral nail should be avoided in pure transcervical fracture neck of femur

Order Reduction of Interval systems using Eigen Spectrum and Factor Division Algorithm

Abstract This paper describes a new approach for the reduction of higher order interval systems using a mixed method in which the numerator of the higher order model is reduced through factor division algorithm and reduced order denominator is obtained using Eigen Spectrum analysis by preserving the pole centroid and system stiffness of the original interval system. The stability of the reduced model is guaranteed, if the original high-order interval system is stable. The proposed method is compared with the other well known existing methods of order reduction. Further, the proposed method is substantiated by a numerical example.