Internal fixator is usually adopted in the treatment of bone fractures. In order to achieve anatomical reduction and effective fixation of fractures, the placement of internal fixators should comply with the biology force line of the bone and adapt to the specific anatomical morphological characteristics of the cortical bone. In order to investigate the distribution characteristics and formation regularity of biology force line and cortical thickness of human bone, three-dimensional model of proximal femur is established by using three-dimensional reconstruction technique in this paper. The normal physiological stress distribution of proximal femur is obtained by finite element analysis under three kinds of behavior conditions: one-legged stance, abduction and adduction. The structural topology optimization method is applied to simulate the cortex of the proximal femur under the combined action of three kinds of behavior conditions, and the anatomic morphological characteristics of the proximal femur are compared. The distribution trend of biology force line of proximal femur and the characteristics of cortex are analyzed. The results show that the biology force lines of bone structure and the morphological characteristics of cortex depend on the load of human activities. The distribution trend of biology force line is related to the direction of trabecular bone and the ridge trend and firmness of cortex when bone is loaded physiologically. The proposed analytical method provides a solution to determine the biology force line of bone and the distribution characteristics of cortex. The conclusions obtained may guide the reasonable placement of internal fixator components of fracture.
Objective To determine the effectiveness and the safety of the Taylor spatial frame in treatment of intermediate or distal tibiofibula fractures. Methods The clinical data of 74 patients with intermediate or distal tibiofibular fractures treated between January 2015 and January 2017 were retrospectively analyzed. According to fixation methods, they were divided into internal fixation group (26 cases) and external fixation group (48 cases). There was no significant difference in the age, gender, cause of injury, type of fracture, time from injury to operation between 2 groups (P>0.05). The intraoperative blood loss, fracture healing time, fixator removal time, and complications were recorded and compared. The final function evaluation criteria of Johner-Wruhs humeral shaft fracture were used to evaluate the function of the affected limb. The lower limb force line recovery after operation was evaluated according to the standard evaluation of LUO Congfenget al. Results Both groups were followed up 6-22 months (median, 14 months). All patients obtained the fracture healing. The intraoperative blood loss, fracture healing time, and fixator removal time were significantly higher in the internal fixation group than those in the external fixation group (P<0.05). There were 1 case of plate exposure, 1 case of delayed fracture healing, and 1 case of plate fracture in the internal fixation group; and there were 2 cases of delayed fracture healing and 4 cases of soft tissue defect in the external fixation group; no significant difference was found in the incidence of complications between 2 groups (χ2=0.015, P=0.904). The function of the affected limb was evaluated by Johner-Wruhs standard at 10 months after operation, the results was excellent in 19 cases, good in 5 cases, and fair in 2 cases in the internal fixation group, with an excellent and good rate of 92.3%; the results was excellent in 42 cases, good in 3 cases, and fair in 2 cases in the external fixation group, with an excellent and good rate of 95.7%; showing no significant difference between 2 groups (χ2=0.392, P=0.531). The lower limb force line recovery after operation was evaluated according to the standard evaluation of LUO Congfeng et al.at 4 months after operation, the results was excellent in 24 cases, fair in 1 case, poor in 1 case in the internal fixation group, with an excellent and good rate of 92.3%; the results was excellent in 46 cases, fair in 1 case, poor in 1 case in the external fixation group, with an excellent and good rate of 95.8%; showing no significant difference between 2 groups (χ2=0.520, P=0.471). Conclusion The use of Taylor spatial frame in the treatment of the intermediate or distal tibiofibular fractures can obviously reduce the healing time and complications than the internal fixation of the plate. It can reduce the fracture treatment cycle and is beneficial to the fracture healing and limb function recovery, which is relatively safe and reliable.
ObjectiveTo explore the safety and effectiveness of Taylor spatial frame (TSF) in the treatment of medial compartmental osteoarthritis (MCOA) of the knee and the adjustment of the lower extremity force line at the same time.MethodsThe clinical data of 30 patients with MCOA who underwent high tibial osteotomy (HTO) between October 2016 and April 2017 were retrospectively analyzed. According to the different fixation methods, they were divided into external fixation group (TSF external fixation, 16 cases) and internal fixation group (locking steel plate internal fixation, 14 cases). There was no significant difference between the two groups in gender, age, side, disease duration, mechanical femur tibia angle (MFTA), and other general data (P>0.05). The operation time and intraoperative blood loss of the two groups were recorded and compared; MFTA was used to evaluate the recovery of the lower extremity force line at last follow-up; Hospital for Special Surgery (HSS) score was used to evaluate the clinical effecacy before operation and at 2 weeks, 1 month, and 3 months after operation.ResultsThe operation time and intraoperative blood loss of external fixation group were significantly less than those of internal fixation group (P<0.05). All patients were followed up 9-16 months, with an average of 12 months. There were 2 cases of delayed healing in the internal fixation group and 1 case of delayed healing in the external fixation group, and all healed after symptomatic treatment. All patients in the two groups had no complication such as needle infection, nonunion at osteotomy, osteomyelitis, and so on. At last follow-up, MFTA standard was used to evaluate the recovery of force line. The results of external fixation group were all excellent, while the results of internal fixation group were excellent in 10 cases and good in 4 cases. The difference between the two groups was significant (Z=–2.258, P=0.024). The HSS scores in the two groups were significantly improved at each time point after operation, and gradually improved with time after operation (P<0.05). The HSS score of the external fixation group was significantly higher than that of the internal fixation group (t=2.425, P=0.022) at 3 months after operation; and there was no significant difference between the two groups at other time points (P>0.05).ConclusionTSF has unique advantages in HTO treatment of MCOA patients and correction of lower extremity force line, such as shorter operation time, less bleeding, firm fixation, and less complications. It can accurately adjust the lower extremity force line after operation and has good effectiveness. It is an effective and safe fixation method.
Objective To investigate the impact of the bone mass and volume of the low-density area under the tibial plateau on the lower limb force line by finite element analysis, offering mechanical evidence for preventing internal displacement of the lower limb force line in conjunction with knee varus in patients with knee osteoarthritis (KOA) and reducing bone mass under the tibial plateau. Methods A healthy adult was selected as the study subject, and X-ray film and CT imaging data were acquired. Mimics 21.0 software was utilized to reconstruct the complete knee joint model and three models representing low-density areas under the tibial plateau with equal volume but varying shapes. These models were then imported into Solidworks 2023 software for assembly and verification. Five KOA finite element models with 22%, 33%, 44%, 55%, and 66% bone mass reduction in the low-density area under tibial plateau and 5 KOA finite element models with 81%, 90%, 100%, 110%, and 121% times of the low-density area model with 66% bone mass loss were constructed, respectively. Under physiological loading conditions of the human lower limb, the distal ends of the tibia and fibula were fully immobilized. An axial compressive load of 1 860 N, following the lower limb force line, was applied to the primary load-bearing area on the femoral head surface. The maximum stress within the tibial plateau, as well as the maximum displacements of the tibial cortical bone and tibial subchondral bone, were calculated and analyzed using the finite element analysis software Abaqus 2022. Subsequently, predictions regarding the alteration of the lower limb force line were made based on the analysis results. Results The constructed KOA model accorded with the normal anatomical structure of lower limbs. Under the same boundary conditions and the same load, the maximum stress of the medial tibial plateau, the maximum displacement of the tibial cortical bone and the maximum displacement of the cancellous bone increased along with the gradual decrease of bone mass in the low-density area under the tibial plateau and the gradual increase in the volume of the low-density area under tibial plateau, with significant differences (P<0.05). ConclusionThe existence of a low-density area under tibial plateau suggests a heightened likelihood of knee varus and inward movement of the lower limb force line. Both the volume and reduction in bone mass of the low-density area serve as critical initiating factors. This information can provide valuable guidance to clinicians in proactively preventing knee varus and averting its occurrence.
Objective To explore the application value of self-made tibial mechanical axis locator in tibial extra-articular deformity in total knee arthroplasty (TKA) for improving the lower extremity force line. Methods Between January and August 2012, 13 cases (21 knees) of osteoarthritis with tibial extra-articular deformity were treated, including 5 males (8 knees) and 8 females (13 knees) with an average age of 66.5 years (range, 58-78 years). The disease duration was 2-5 years (mean, 3.5 years). The knee society score (KSS) was 45.5 ± 15.5. Extra-articular deformities included 1 case of knee valgus (2 knees) and 12 cases of knee varus (19 knees). Preoperative full-length X-ray films of lower extremities showed 10-21° valgus or varus deformity of tibial extra joint. Self-made tibial mechanical axis locator was used to determine and mark coronal tibial mechanical axis under X-ray before TKA, and then osteotomy was performed with extramedullary positioning device according to the mechanical axis marker. Results All incisions healed by first intention, without related complications of infection and joint instability. All patients were followed up 5-12 months (mean, 8.3 months). The X-ray examination showed lt; 2° knee deviation angle in the others except 1 case of 2.9° knee deviation angle at 3 days after operation, and the accurate rate was 95.2%. No loosening or instability of prosthesis occurred during follow-up. KSS score was 85.5 ± 15.0 at last follow-up, showing significant difference when compared with preoperative score (t=12.82, P=0.00). Conclusion The seft-made tibial mechanical axis locator can improve the accurate rate of the lower extremity force line in TKA for tibia extra-articular deformity.
ObjectiveTo explore the surgical technique and effectiveness of limited bone and soft tissue surgery combined with Ilizarov technique in the treatment of adolescents severe cerebral palsy with flattened valgus foot and lower leg external rotation deformity. MethodsA retrospective analysis was conducted on 12 patients with severe cerebral palsy with flattened valgus foot and external rotation deformity of the lower leg, totaling 16 feet, admitted between January 2022 and January 2025. There were 5 males with 7 feet and 7 females with 9 feet, the age ranged from 12 to 18 years, with an average of 15 years. There were 10 cases on the left foot, 6 cases on the right foot, and 4 cases on both feet. The preoperative external rotation angle of the lower leg ranged from 20° to 35°, with an average of 26°. The preoperative visual analogue scale (VAS) score was 4.9±0.9, the American Orthopaedic Foot & Ankle Society (AOFAS) score was 68.7±12.0, the calcaneal tilt angle was (12.69±1.78)°, and the hindfoot angle was (18.69±3.55)°. Patients with bilateral lower leg deformities underwent surgery in two phases, with an interval of 3-6 months between surgeries. Select soft tissue surgery (Achilles tendon elongation, release or transposition of joint capsule and ligaments) and bone surgery (joint fusion, calcaneal osteotomy, medial wedge osteotomy, etc.) combined with tibiofibular internal rotation osteotomy and Ilizarov external fixation were selected according to the patient’s condition. At 1 week after operation, the external fixators of the lower leg and ankle were slowly adjusted, and the deformities that were not completely solved in the three-dimensional correction operation were corrected. Postoperative pain relief and functional recovery were evaluated by VAS and AOFAS scores, and the improvement of foot deformity was evaluated by calcaneal tilt angle and hindfoot angle on radiographic data, and the postoperative effctiveness was evaluated according to the International Clubfoot Study Group (ICFSG). Results At 2 weeks after operation, the foot deformity of the patient was basically adjusted. All patients were followed up 6-36 months, with an average of 18 months. The incisions healed by first intention without nerve injury, infection, or other complications. At last follow-up, the patients recovered satisfactorily, the osteotomy sites healed, and the external rotation of the lower leg was corrected. The VAS score was 1.2±0.1 and AOFAS score was 86.7±6.8, which were significantly different from those before operation (P<0.05). The calcaneal tilt angle was (18.38±1.15)° and the hindfoot angle was (10.06±2.93)°, which were significantly different from those before operation (P<0.05). According to the ICFSG scoring standard, 13 feet were excellent and 3 feet were good, and the excellent and good rate was 100%. ConclusionThe combination of bone and soft tissue limited surgery and Ilizarov technique is a safe, minimally invasive, and effective method for treating severe cerebral palsy in adolescents with flattened valgus foot and external rotation deformity of the lower leg. It conforms to biological principles and follows the concept of natural bone reconstruction.