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Research paper thumbnail of Femoral allograft in the management of osseous hydatidosis presenting as femoral shaft non-union

Archives of Orthopaedic and Trauma Surgery, 2009

Osseous hydatidosis is a rare infection posing diagnostic and therapeutic challenge. We present a... more Osseous hydatidosis is a rare infection posing diagnostic and therapeutic challenge. We present a case of extensive hydatidosis of the femoral shaft with non-union of pathologic fracture. Patient had resection of involved femur and post-operative chemotherapy. Subsequently femur reconstruction was done using a femoral allograft. At 26 months patient has no recurrence and bony union is seen at host-allograft interface. We present this technique as an extended indication of allograft used in limb reconstruction.

Research paper thumbnail of Giant cell tumor of the patella and its management using a patella, patellar tendon, and tibial tubercle allograft

Knee Surgery Sports Traumatology Arthroscopy, 2010

Patellar neoplasms are rare. We present a case of aggressive giant cell tumor of patella with ext... more Patellar neoplasms are rare. We present a case of aggressive giant cell tumor of patella with extensive involvement of patella and patellar tendon. Its management with wide resection of tumor and reconstruction of extensor mechanism with patella bone tendon allograft is discussed. The patient has good results at 3 years follow-up.

Research paper thumbnail of Effect of Active Muscle Forces on Knee Injury Risks for Pedestrian Standing Posture at Low-Speed Impacts

Traffic Injury Prevention, 2008

Objectives: The objective of the present study is to investigate the effect of muscle active forc... more Objectives: The objective of the present study is to investigate the effect of muscle active forces on lower extremity injuries for various impact locations and impact angles for a freely standing pedestrian. Methods: FE simulations have been performed using a validated lower extremity FE model with active muscles (A-LEMS). In all, nine impact orientations have been studied. For each impact orientation, three different pre-impact conditions of a freely standing pedestrian, representing a cadaver, and an unaware and an aware braced pedestrian, have been simulated. Stretch-based reflexive action was included in the simulations for an unaware pedestrian. Results: Strains in knee ligaments and knee joint kinematics have been compared in each impact orientation to assess the effect of muscle activation. It is observed that strain in knee ligaments is dependent on impact locations and angles and the MCL is the most vulnerable ligament. Further, due to muscle effects, except when the impact is on the knee, peak strain values in all the ligaments are lower for an unaware pedestrian than either for a cadaver or for a fully braced pedestrian. Conclusions: It is concluded that active muscle forces significantly affect the knee kinematics and consequently reduce strains in knee ligaments.

Research paper thumbnail of Response of tonic lower limb FE model in various real life car-pedestrian impact configurations: a parametric study for standing posture

International Journal of Vehicle Safety, 2009

This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedes... more This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedestrian lateral impacts. Three variables, viz. height of impact, pedestrian offset with respect to car centre and impact speed, are considered. Full-scale car-pedestrian FE simulations have been performed using the full body pedestrian model with active lower extremities (PMALE) and front structures of a car model. Two pre-impact conditions of a symmetrically standing pedestrian, representing a cadaver and an unaware pedestrian, have been simulated. It is concluded that (1) with muscle contraction risk of ligament failure decreases whereas risk of bone fracture increases; (2) ligament and bone strains are dependent on the impact location;

Research paper thumbnail of Effect of muscle contraction on the lower limb response in low speed car–pedestrian lateral impact: simulations for a walking pedestrian

International Journal of Crashworthiness, 2010

This paper investigates the effect of muscle contraction on lower extremity injuries for pedestri... more This paper investigates the effect of muscle contraction on lower extremity injuries for pedestrian walking posture in a car–pedestrian lateral impact at low speed. The full body model, pedestrian model with active lower extremities (PMALE), which was configured in a symmetric standing posture, has been repositioned in the walking posture. Finite-element simulations have then been performed using the PMALE in walking posture and front structures of a car. Two impact configurations, i.e. impact on the right and left legs, have been simulated. Two pre-impact conditions, that of a symmetrically standing pedestrian representing a cadaver and an unaware pedestrian, have been simulated for both the impact configurations. Stretch-based reflexive action was included in the simulations for an unaware pedestrian. It is concluded that (1) with muscle contraction, the risk of ligament failure decreases whereas the risk of bone fracture increases; (2) in lateral impacts, Medial Collateral Ligament (MCL) could be considered as the most vulnerable and Lateral Collateral Ligament (LCL) as the safest ligament; and (3) for a walking pedestrian, Posterior Cruciate Ligament (PCL) would be at a higher risk in the case of impact on the rear leg, whereas Anterior Cruciate Ligament (ACL) would be at a higher risk if car strikes the front leg.

Research paper thumbnail of Response of lower limb in full-scale car–pedestrian low-speed lateral impact – influence of muscle contraction

International Journal of Crashworthiness, 2009

This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedes... more This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedestrian lateral impact. A full-body pedestrian model with active muscles has been developed. Finite element simulations have then been performed using the full-body model and front structure of a car. Two pre-impact conditions, that of a symmetrically standing pedestrian, representing a cadaver and an unaware pedestrian, have been simulated. Stretch-based reflexive action was included in the simulations for an unaware pedestrian. The results show that due to muscle contraction (1) peak strain in all the knee ligaments reduces, (2) von Mises stresses in tibia and fibula increase and may fail and (3) knee joint effective stiffness increases by 58% in lateral bending.

Research paper thumbnail of Giant-cell tumour of the tendon sheath

Journal of Bone and Joint Surgery-british Volume, 2000

An unusual case of giant-cell tumours of the tendon sheath (syn. Pigmented villonodular tenosynov... more An unusual case of giant-cell tumours of the tendon sheath (syn. Pigmented villonodular tenosynovitis or fibrous xanthoma) of a long thumb flexor is presented. The unusual features are: two distinctly different tumours of almost similar size and shape arising from the tendon sheath at its either ends but with a segment of normal tendon sheath in between and presence of early malignant changes in the distal tumour with a benign proximal one, confirmed microscopically. Lastly, radiograph showed definite bony involvement in the proximal phalanx of the thumb. On extensive review of the literature, I found reports of rare presentation of malignant changes and bony erosion, but none had these various features.

Research paper thumbnail of Trapezius transfer for deltoid paralysis

Journal of Bone and Joint Surgery-british Volume, 1998

W e have reviewed 26 patients treated by trapezius transfer for deltoid paralysis due to brachial... more W e have reviewed 26 patients treated by trapezius transfer for deltoid paralysis due to brachial plexus injury or old poliomyelitis. We assessed the power of shoulder abduction and the tendency for subluxation. There were good results in 16 patients (60%); five were fair and five poor.

Research paper thumbnail of Biodata 2 2

Research paper thumbnail of Femoral allograft in the management of osseous hydatidosis presenting as femoral shaft non-union

Archives of Orthopaedic and Trauma Surgery, 2009

Osseous hydatidosis is a rare infection posing diagnostic and therapeutic challenge. We present a... more Osseous hydatidosis is a rare infection posing diagnostic and therapeutic challenge. We present a case of extensive hydatidosis of the femoral shaft with non-union of pathologic fracture. Patient had resection of involved femur and post-operative chemotherapy. Subsequently femur reconstruction was done using a femoral allograft. At 26 months patient has no recurrence and bony union is seen at host-allograft interface. We present this technique as an extended indication of allograft used in limb reconstruction.

Research paper thumbnail of Giant cell tumor of the patella and its management using a patella, patellar tendon, and tibial tubercle allograft

Knee Surgery Sports Traumatology Arthroscopy, 2010

Patellar neoplasms are rare. We present a case of aggressive giant cell tumor of patella with ext... more Patellar neoplasms are rare. We present a case of aggressive giant cell tumor of patella with extensive involvement of patella and patellar tendon. Its management with wide resection of tumor and reconstruction of extensor mechanism with patella bone tendon allograft is discussed. The patient has good results at 3 years follow-up.

Research paper thumbnail of Effect of Active Muscle Forces on Knee Injury Risks for Pedestrian Standing Posture at Low-Speed Impacts

Traffic Injury Prevention, 2008

Objectives: The objective of the present study is to investigate the effect of muscle active forc... more Objectives: The objective of the present study is to investigate the effect of muscle active forces on lower extremity injuries for various impact locations and impact angles for a freely standing pedestrian. Methods: FE simulations have been performed using a validated lower extremity FE model with active muscles (A-LEMS). In all, nine impact orientations have been studied. For each impact orientation, three different pre-impact conditions of a freely standing pedestrian, representing a cadaver, and an unaware and an aware braced pedestrian, have been simulated. Stretch-based reflexive action was included in the simulations for an unaware pedestrian. Results: Strains in knee ligaments and knee joint kinematics have been compared in each impact orientation to assess the effect of muscle activation. It is observed that strain in knee ligaments is dependent on impact locations and angles and the MCL is the most vulnerable ligament. Further, due to muscle effects, except when the impact is on the knee, peak strain values in all the ligaments are lower for an unaware pedestrian than either for a cadaver or for a fully braced pedestrian. Conclusions: It is concluded that active muscle forces significantly affect the knee kinematics and consequently reduce strains in knee ligaments.

Research paper thumbnail of Response of tonic lower limb FE model in various real life car-pedestrian impact configurations: a parametric study for standing posture

International Journal of Vehicle Safety, 2009

This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedes... more This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedestrian lateral impacts. Three variables, viz. height of impact, pedestrian offset with respect to car centre and impact speed, are considered. Full-scale car-pedestrian FE simulations have been performed using the full body pedestrian model with active lower extremities (PMALE) and front structures of a car model. Two pre-impact conditions of a symmetrically standing pedestrian, representing a cadaver and an unaware pedestrian, have been simulated. It is concluded that (1) with muscle contraction risk of ligament failure decreases whereas risk of bone fracture increases; (2) ligament and bone strains are dependent on the impact location;

Research paper thumbnail of Effect of muscle contraction on the lower limb response in low speed car–pedestrian lateral impact: simulations for a walking pedestrian

International Journal of Crashworthiness, 2010

This paper investigates the effect of muscle contraction on lower extremity injuries for pedestri... more This paper investigates the effect of muscle contraction on lower extremity injuries for pedestrian walking posture in a car–pedestrian lateral impact at low speed. The full body model, pedestrian model with active lower extremities (PMALE), which was configured in a symmetric standing posture, has been repositioned in the walking posture. Finite-element simulations have then been performed using the PMALE in walking posture and front structures of a car. Two impact configurations, i.e. impact on the right and left legs, have been simulated. Two pre-impact conditions, that of a symmetrically standing pedestrian representing a cadaver and an unaware pedestrian, have been simulated for both the impact configurations. Stretch-based reflexive action was included in the simulations for an unaware pedestrian. It is concluded that (1) with muscle contraction, the risk of ligament failure decreases whereas the risk of bone fracture increases; (2) in lateral impacts, Medial Collateral Ligament (MCL) could be considered as the most vulnerable and Lateral Collateral Ligament (LCL) as the safest ligament; and (3) for a walking pedestrian, Posterior Cruciate Ligament (PCL) would be at a higher risk in the case of impact on the rear leg, whereas Anterior Cruciate Ligament (ACL) would be at a higher risk if car strikes the front leg.

Research paper thumbnail of Response of lower limb in full-scale car–pedestrian low-speed lateral impact – influence of muscle contraction

International Journal of Crashworthiness, 2009

This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedes... more This paper investigates the effect of muscle contraction on lower extremity injuries in car-pedestrian lateral impact. A full-body pedestrian model with active muscles has been developed. Finite element simulations have then been performed using the full-body model and front structure of a car. Two pre-impact conditions, that of a symmetrically standing pedestrian, representing a cadaver and an unaware pedestrian, have been simulated. Stretch-based reflexive action was included in the simulations for an unaware pedestrian. The results show that due to muscle contraction (1) peak strain in all the knee ligaments reduces, (2) von Mises stresses in tibia and fibula increase and may fail and (3) knee joint effective stiffness increases by 58% in lateral bending.

Research paper thumbnail of Giant-cell tumour of the tendon sheath

Journal of Bone and Joint Surgery-british Volume, 2000

An unusual case of giant-cell tumours of the tendon sheath (syn. Pigmented villonodular tenosynov... more An unusual case of giant-cell tumours of the tendon sheath (syn. Pigmented villonodular tenosynovitis or fibrous xanthoma) of a long thumb flexor is presented. The unusual features are: two distinctly different tumours of almost similar size and shape arising from the tendon sheath at its either ends but with a segment of normal tendon sheath in between and presence of early malignant changes in the distal tumour with a benign proximal one, confirmed microscopically. Lastly, radiograph showed definite bony involvement in the proximal phalanx of the thumb. On extensive review of the literature, I found reports of rare presentation of malignant changes and bony erosion, but none had these various features.

Research paper thumbnail of Trapezius transfer for deltoid paralysis

Journal of Bone and Joint Surgery-british Volume, 1998

W e have reviewed 26 patients treated by trapezius transfer for deltoid paralysis due to brachial... more W e have reviewed 26 patients treated by trapezius transfer for deltoid paralysis due to brachial plexus injury or old poliomyelitis. We assessed the power of shoulder abduction and the tendency for subluxation. There were good results in 16 patients (60%); five were fair and five poor.

Research paper thumbnail of Biodata 2 2