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1.  In vitro comparison of resistance to implant failure in unstable trochanteric fractures fixed with intramedullary single screw versus double screw device 
Indian Journal of Orthopaedics  2014;48(3):306-312.
The purpose of this study was to compare the resistance of intramedullary single screw device (Gamma nail) and double screw device proximal femoral nail (PFN) in unstable trochanteric fractures in terms of the number of cycles sustained, subsidence and implant failure in an axial loading test in cadaveric femora.
Materials and Methods:
The study was conducted on 18 dry cadaveric femoral specimens, 9 of these were implanted with a Gamma nail and 9 with PFN. There was no significant difference found in average dual energy X-ray absorptiometry value between both groups. The construct was made unstable (AO type 31A3.3) by removing a standard sized posteromedial wedge. These were tested on a cyclic physiological loading machine at 1 cycle/s with a load of 200 kg. The test was observed for 50,000 loading cycles or until implant failure, whichever occurred earlier. Peak displacements were measured and analysis was done to determine construct stiffness and gap micromotion in axial loading.
It was observed that there was statistically significant difference in terms of displacement at the fracture gap and overall construct stiffness of specimens of both groups. PFN construct group showed a mean subsidence of 1.02 mm and Gamma nail construct group showed mean subsidence of 2.36 mm after cycling. The average stiffness of Gamma nail group was 62.8 ± 8.4 N/mm which was significantly lower than average stiffness of the PFN group (80.4 ± 5.9 N/mm) (P = 0.03). In fatigue testing, 1 out of 9 PFN bone construct failed, while 5 of 9 Gamma nail bone construct failed.
When considering micromotion (subsidence) and incidence of implant/screw failure, double screw device (PFN) had statistically significant lower micromotion across the fracture gap with axial compression and lower incidence of implant failure. Hence, double screw device (PFN) construct had higher stability compared to single screw device (GN) in an unstable trochanteric fracture femur model.
PMCID: PMC4052032  PMID: 24932039
Cyclic loading; Gamma nail; proximal femoral nail; subsidence
2.  Role of autologous chondrocyte transplantation in articular cartilage defects: An experimental study 
Indian Journal of Orthopaedics  2013;47(2):129-134.
Injuries of articular cartilage (AC) have very limited potential to heal, because they are avascular and this may subsequently lead to secondary arthrosis. Autologous cultured chondrocytes transplantation is can be used to create hyaline or hyaline-like repair in a cartilage defect area. The purpose of this study was to repair artificially created full-thickness AC defects in 20 rabbit knee joints with autologous cultured chondrocytes.
Materials and Methods:
An AC defect of 3 mm was created on the lateral condyle of both tibiae. The defect was filled with autologous chondrocytes cultured in vitro and fixed with fibrin, at a later stage on the left side. The right knee acted as a control. The rabbits were sacrificed after 3, 6, and 12 weeks of transplantation and the reparative tissues were analyzed macroscopically and histologically.
Histological scores of the cultured autologous chondrocyte transplanted knees were significantly better than the control knees at 3, 6, and 12 weeks following the transplantation. Integration of repaired tissue with adjacent cartilage, hyaline characteristics of repaired tissue, maturity of cartilage, and cellularity increases with duration and is significant in chondrocytes-transplanted defects compared to control. The histological scores also become better with increasing duration of followup.
Transplantation of autologous chondrocytes cultured in vitro and fixed with fibrin is effective in repairing AC defects.
PMCID: PMC3654461  PMID: 23682173
Cartilage; cultured chondrocyte transplantation; articular cartilage defects
3.  Tourniquets in orthopedic surgery 
PMCID: PMC3601226  PMID: 23533297
4.  Basic research: Issues with animal experimentations 
In vivo studies using the animals are helpful in developing the treatment strategies as they are important link between the successful in vitro testing and safe human use. Various research projects in the field of fixation of fractures, development of newer biomaterials, chemotherapeutic drugs, use of stem cells in nonunion of fractures and cartilage defects etc., have hugely depended on animal experimentation. The employment of animals in experiments is both scientific and ethical issue. There must be reasonable reasons to show that it will significantly advance the present knowledge and lead to improvement in care. The regulatory bodies exist for humane use and care of animals used for experiments e.g., International Council for Laboratory Animal Science, Council for International Organizations of Medical Sciences, International Union of Biological Sciences, International Committee on Laboratory Animals. In India, Indian National Science Academy, Indian Council of Medical Research, National Centre for Laboratory Animal Sciences promote high standards of laboratory animal quality, care and health. The Committee for the Purpose of Control and Supervision on Experiments on Animals guidelines are well defined and is a must read document for any one interested to carry out research with animal facilities.
PMCID: PMC3601236  PMID: 23532705
Animal experimentations; basic science; orthopedic research
5.  Bicentric bipolar hip prosthesis: A radiological study of movement at the interprosthetic joint 
Indian Journal of Orthopaedics  2011;45(6):508-513.
The bipolar hip prostheses after some time functions as a unipolar device. There is a need to change the design of bipolar hip prostheses to make it function as a bipolar device over a prolonged period of time. A bicentric bipolar hip prosthesis was used as an implant for various conditions of the hip. We evaluated the movement of this newly developed prosthesis at the interprosthetic joint radiologically at periodic intervals.
Materials and Methods:
Fifty two cases were operarted with the Bicentric bipolar prosthesis for indications like fracture neck of femur and various other diseases of the hip and were followed up with serial radiographs at periodic intervals to evaluate, what fraction of the total abduction at the hip was occurring at the interprosthetic joint.
In cases of intracapsular fracture neck of femur, the percentage of total abduction occurring at the interprosthetic joint at 3 months follow-up was 33.74% (mean value of all the patients), which fell to 25.66% at 1.5 years. In indications for bipolar hemireplacement other than fracture neck of femur, the percentage of total abduction occurring at the interprosthetic joint at 3 months follow-up was 71.71% (mean value) and at 1.5 years it was 67.52%.
This study shows the relative preservation of inner bearing movement in the bipolar hip prosthesis with time probably due its refined design. Further refinements are needed to make the prosthesis work better in patients of intracapsular fracture neck femur.
PMCID: PMC3227354  PMID: 22144743
Bicentric bipolar prosthesis; inner bearing; interprosthetic joint

Results 1-5 (5)