OBJECTIVETo investigate the biomechanics effect due to unilateral cortical bone defect of different size in long tubular bone.

METHODSSeventy-six pieces of Sanhuang cock tibial were randomly divided into 7 groups. The unilateral diaphyses cortical were drilled holes of different size, include 1.5, 2.0, 2.5, 3.0, 3.5, and 4.5 mm, performed three-points bend single experiment. The intact bone cortical group was control group.

RESULTSWhen there were bone structure destructions, the maximum of the bend load between 3 groups which bone defect diameter were 1.5 mm, 2.0 mm, and control was not significant difference (P = 0.824, 0.865), but the maximum of the bend load between 3 groups which bone defect diameter were 2.5, 3.0, and 3.5 mm decreasing about 14 percent of the control group (P = 0.015, 0.010, 0.021). and the maximum of the bend load which bone defect diameter were 4.5 mm decrease about 23 percent of the control group (P = 0.001).

CONCLUSIONSIf the diameter of bone cortical defect is within 22.63 +/- 1.39 percent of bone cortical outer diameter, there was no reduction of the bend load. If the diameter of bone cortical defect is beyond 29.36 +/- 2.07 percent of bone cortical outer diameter, it decreases the maximum bend load of the long tubular bone, but the reduced range is not complete with direct ratio to the bone defect size.

Animals ; Biomechanical Phenomena ; Chickens ; Diaphyses ; injuries ; physiopathology ; Random Allocation ; Stress, Mechanical ; Tibia ; injuries ; physiopathology ; Weight-Bearing

Dynamic loads at knee joint of amputee are fundamental for rehabilitation of knee injury and prosthesis design. In this paper, a 3-D model for calculation of dynamic load at knee joint of trans-tibial amputee was developed. Gait analysis was done on three terrains including normal level walking, upstairs and downstairs. Dynamic loads at knee joint were calculated during one gait cycle. The results show that gait patterns and dynamic loads at knee joint were different among these three terrains. Although the general waveforms were about the same, the motion range of knee joint, ground reaction forces and loads at knee joint when walking upstairs or downstairs were larger than those in a normal level walking. The quantitative findings provide the theoretical basis of gait analysis and prosthesis design for trans-tibial amputee.
Amputation Stumps ; physiopathology ; Artificial Limbs ; Biomechanical Phenomena ; Gait ; physiology ; Humans ; Knee Joint ; physiopathology ; Leg ; physiopathology ; surgery ; Prosthesis Design ; Stress, Mechanical ; Tibia ; physiopathology ; surgery ; Walking ; physiology ; Weight-Bearing ; physiology

OBJECTIVETo evaluate the interface characteristics of the new-designed locking plate (LP) and limited contact-dynamic compression plate (LC-DCP) and compare the fracture healing between LP and LC-DCP in a goat tibia fracture model.

METHODSEight-hole LP and LC-DCP were applied to fix fresh goat tibiae in a reproducible manner. The average pressure, force and interface contact area were calculated using Fuji prescale pressure sensitive film interposed among the plate and the bone and image analysis system. Eight-hole LP and LC-DCP were applied to each tibia in a goat tibia fracture model. The fracture healing was evaluated by X-ray photography at postoperative 8 weeks. The goats were sacrificed at postoperative 12 weeks. Three-point bending test was conducted in the tibiae.

RESULTSThe interface contact of LP system was smaller than that of LC-DCP (P < 0.05), while interface contact force of LP system was higher than that of LC-DCP (P < 0.05). Radiographs revealed that the fracture line disappeared in the LP group, while the fracture line was visible in DCP group at postoperative 8 weeks. At postoperative 12 weeks, the bending strength and bending load of fractured tibia were higher in LP group than in DCP group, respectively.

CONCLUSIONThe new-designed locking plate can significantly decrease the contact area on the bone interface, which further provides better fracture healing than conventional plates.

Animals ; Biomechanical Phenomena ; Bone Plates ; Fracture Fixation, Internal ; Fracture Healing ; Goats ; Internal Fixators ; Tibia ; physiopathology ; Tibial Fractures ; physiopathology ; surgery

OBJECTIVETo explore a new technique of reduction and internal fixation for tibia intercondylar eminence fractures under arthroscopy.

METHODSFrom June 2004 to February 2006, 9 patients with fresh tibia intercondylar eminence fracture (type II in 4 cases and type III in 5 cases) were treated with reduction and internal fixation using suture anchors (Depuy Mitek) under arthroscopy. All the patients, subject to regular post-operation functional exercise, were followed up for 6 to 22 months. The results were evaluated in the aspects of fracture reduction healing, knee joint relaxation and ROM, and functional restoration of overall limbs.

RESULTSIn the nine patients, the tibia intercondylar eminence fractures healed without displacement and nonunion. No knee joint relaxation or extension-restriction was found. Lysholm score indicated 93.8 +/- 2.3 at the 6th postoperative months.

CONCLUSIONThe reduction and internal fixation of tibia intercondylar eminence fractures under arthroscopy using suture anchors demonstrate a reliable and easy-to-use technique. Operation under arthroscopy helps diagnose and treat other complications inside knee joint, merely resulting in slight injury. In addition,early functional exercise contributes to rapid recovery of knee joint's functions.

Adult ; Arthroscopy ; Female ; Fracture Fixation, Internal ; methods ; Humans ; Male ; Middle Aged ; Suture Anchors ; Tibia ; physiopathology ; surgery ; Tibial Fractures ; physiopathology ; surgery

BACKGROUNDSurgery for severe kyphoscoliosis is frequently unsatisfying because of loss of correction, high rate of pseudarthrosis and neurological complications. Several authors reported that the anterior fusion with strut grafts might improve the surgical outcome. This article describes and assesses the surgical strategies and the application of autogenous tibial strut in the treatment of severe kyphoscoliosis.

METHODSSevere kyphoscoliosis patients (n = 39) admitted from April 1998 to September 2003 formed the study group. Different surgical strategies had been used according to the flexibility, neurological function and curve level. All patients received staged anterior and posterior surgery with a tibial strut used in the anterior fusion. The patients were followed up for 9 months to 6 years (mean 37 months).

RESULTSThe mean preoperative and postoperative kyphosis was 82 degrees and 52 degrees respectively, and the mean scoliosis was 84 degrees and 44 degrees respectively. Complications included pseudarthrosis (2 cases, one with graft fracture and the other with hook displacement), posterior elements fractures (4), pleura penetrations (3, in the plastic surgery of the thoracic cage), dura tear (2), exudative pleuritis (2, in the anterior surgery), and tibia fracture of the harvesting site (1). The mean loss of correction in coronal and sagittal plane was 6 degrees and 7 degrees respectively. Except for 1 case, the patients with incomplete paraplegia showed improvements to varying extents.

CONCLUSIONAutogenous tibial strut can provide excellent support to the kyphoscoliotic spine: it reduces pseudarthrodic rate, loss of correction and complications of graft harvest, it also prevents the occurrence of neurological impairment.

Adolescent ; Adult ; Child ; Female ; Humans ; Kyphosis ; physiopathology ; surgery ; Male ; Scoliosis ; physiopathology ; surgery ; Spinal Fusion ; Tibia ; transplantation ; Transplantation, Autologous

OBJECTIVETo investigate results of total knee arthroplasty using the long-stem tibial component combined with metallic wedge of knee prosthesis for the treatment of proximal defects.

METHODSFrom January 2011 to May 2013, 10 patients (11 knees) were treated with total knee arthroplasties using the long-stem tibial component with metallic tibial wedge of knee prosthesis. All the patients were female and the average age was 67 years old (ranged, 60 to 77 years old). All the patients were osteoarthritis. All the patients were classified as T2A style. The patients were evaluated according to knee score system (KSS).

RESULTSAll the patients were followed up for 12 months on average (ranged 3 to 29 months). The clinical outcome was assessed using KSS score, including knee pain score, knee stability score, knee range of motion score and knee walking score, knee stairs score. There were significantly differences at 6 weeks, 3 months, 6 months and 12 months between pre-and postoperative KSS score.

CONCLUSIONThe mechanical stability of tibial fixation in primary TKA is significantly increased by using the long-stem tibial component with metallic wedge of knee prosthesis, even in the presence of poor proximal bone.

Aged ; Arthroplasty, Replacement, Knee ; Female ; Humans ; Knee Joint ; physiopathology ; surgery ; Knee Prosthesis ; Male ; Osteoarthritis, Knee ; physiopathology ; surgery ; Range of Motion, Articular ; Tibia ; abnormalities ; physiopathology ; surgery

OBJECTIVETo compare the mechanical properties of point contact-dynamic compression plate (PC-DCP) and its effects on cortical bone perfusion with that of dynamic compression plates (DCP) in goat tibiae.

METHODSTwenty pairs of matched fresh goat tibiae were used. A transverse fracture model was established. The fractures with a 3mm interspace between the fracture ends were subject to fixations with the DCPs and the PC-DCPs respectively, then the four-points bending tests and the torsion tests were conducted to compare the mechanical properties of the PC-DCP with that of DCP. Another 13 sexually mature goats underwent fixations with the DCPs and the PC-DCPs, respectively, at the mid-shafts of the intact bilateral tibiae. Ischemic zones were observed at four time points (1 day, 2, 6, and 12 weeks after operation) using disulphine blue staining technique.

RESULTSThere were no significant differences in mechanical properties, such as bend- and torsion-resistance, between the DCPs and the PC-DCPs. One day, 2, and 6 weeks after operation, on the side of DCP fixation, outer cortical bone ischemia under the plate persisted, and this condition did not reverse until 12 weeks after operation. However, on the side of PC-DCP fixation, cortical bone ischemia occurred only in the periphery of the screw holes and at the contact sites of the PC NUTs 1 day after operation, and it disappeared at 2 weeks after operation.

CONCLUSIONSThe PC-DCP has similar biomechanical properties of the DCP, but is less detrimental to local bone blood circulation than the conventional plates.

Animals ; Biomechanical Phenomena ; Bone Plates ; Fracture Fixation, Internal ; instrumentation ; Goats ; Staining and Labeling ; Tibia ; blood supply ; Tibial Fractures ; physiopathology ; surgery

In this study, we compared the three-point bending test of the metaphyseal tibia versus the three-point bending test of the diaphysial tibia in rats. Twenty 6-month-old female Sprague-Dawley rats were randomly divided into the ovariectomized (OVX) group and the sham-operated (Sham) group. All rats were housed in standard environmental conditions. Five months after operation, all rats were sacrificed by depletion method. All left tibia were removed for the three-point bending test. The changes of mechanical parameters were examined by the three-point bending test of the metaphyseal tibia and by that of the diaphysial tibia. Elastic, Maximum Load, Maximum Stress, Failure Load, and Failure Stress of the metaphyseal tibia were much lower in OVX rats than in Sham rats. However, there was no statistically significant difference in all of the mechanical parameters of the diaphysial tibia between the OVX group and the Sham group. The new three-point bending test of the metaphyseal tibia is much more sensitive and useful as compared with the test of the diaphysial tibia in evaluating the changes of mechanical properties of tibia in osteoporotic rats.
Animals ; Biomechanical Phenomena ; Bone Density ; physiology ; Female ; Osteoporosis ; pathology ; physiopathology ; Ovariectomy ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Tibia ; physiology

Cadaver ; Humans ; India ; Models, Anatomic ; Models, Neurological ; Peroneal Nerve ; anatomy & histology ; Piriformis Muscle Syndrome ; physiopathology ; Sciatic Nerve ; anatomy & histology ; physiopathology ; Sciatica ; pathology ; Tibia ; innervation ; pathology

OBJECTIVETo evaluate biomechanical properties in different methods of internal fixation combined with distal tibiofibular syndesmosis injury, in order to provide a theoretical basis for clinical choice.

METHODSSix lower limbs specimens were collected and divided into 5 groups, including normal group, distal tibiofibular syndesmosis injury (injury group), 3 cortexes group, 4 cortexes group and hook-plate fixation group. Neutral position, plantar flexion position (30°), dorsiflexion (20°) supination external rotation position of foot movement were simulated on universal materials tester. Strength, stiffness and stability of ankle joint in 4 kinds of motion conditions were measured.

RESULTSThere was significant differences in strength and stiffness of ankle joint between injury group and normal group in 4 different kinds of motion conditions (P<0.05). Strength and stiffness of ankle joint in 3 cortexes group, 4 cortexes group and hook-plate fixation group were improved obviously in 4 different kinds of motion conditions, and biomechanical indexes were recovered normally or better than normal group. Stiffness of the three fixation groups were better than normal group,but there was no significant differences among three groups (P > 0.05), while stiffness of hook-plate fixation group was closed to normal group.

CONCLUSIONFor distal tibiofibular syndesmosis injury, 1 screw with 3 cortexes, 4 cortexes and hook-plate had a positive impact on strength, stiffness and stability of distal tibiofibular syndesmosis injury stress,and could restore the normal stabllity of ankle joint after reconstruction. While fixing by screw fixation would limit the rototary motion of ankle joint,ankle mortise could not adapt to changes of talus bone, thus induces screw breakage and traumatic arthritis. Hook-plate fixation is more suitable than 3 cortexes or 4 cortexes fixation for bilmechanical properties,and its' stress is more balance and can reduce postoperative complcations.

Ankle Injuries ; physiopathology ; surgery ; Biomechanical Phenomena ; Fibula ; injuries ; surgery ; Fracture Fixation, Internal ; methods ; Humans ; Joint Instability ; physiopathology ; prevention & control ; Reconstructive Surgical Procedures ; methods ; Tibia ; injuries ; surgery