Predicting Tibia-Fibula Geometry and Density From Anatomical Landmarks Via Statistical Appearance Model: Influence of Errors on Finite Element-Calculated Bone Strain.

State-of-the-art participant-specific finite element models require advanced medical imaging to quantify bone geometry and density distribution; access to and cost of imaging is prohibitive to the use of this approach. Statistical appearance models may enable estimation of participants' geometry and density in the absence of medical imaging. The purpose of this study was to: (1) quantify errors associated with predicting tibia-fibula geometry and density distribution from skin-mounted landmarks using a statistical appearance model and (2) quantify how those errors propagate to finite element-calculated bone strain. Participant-informed models of the tibia and fibula were generated for thirty participants from height and sex and from twelve skin-mounted landmarks using a statistical appearance model. Participant-specific running loads, calculated using gait data and a musculoskeletal model, were applied to participant-informed and CT-based models to predict bone strain using the finite element method. Participant-informed meshes illustrated median geometry and density distribution errors of 4.39-5.17 mm and 0.116-0.142 g/cm3, respectively, resulting in large errors in strain distribution (median RMSE = 476-492 µÎµ), peak strain (limits of agreement =±27-34%), and strained volume (limits of agreement =±104-202%). These findings indicate that neither skin-mounted landmark nor height and sex-based predictions could adequately approximate CT-derived participant-specific geometry, density distribution, or finite element-predicted bone strain and therefore should not be used for analyses comparing between groups or individuals.

Pronounced cortical porosity and sex-specific patterns of increased bone and osteocyte lacunar mineralization characterize the human distal fibula with aging.

The high occurrence of distal fibula fractures among older women suggests a potential link to impaired bone health. Here we used a multiscale imaging approach to investigate the microarchitecture, mineralization, and biomechanics of the human distal fibula in relation to age and sex. Micro-computed tomography was performed to analyze the local volumetric bone mineral density and various microarchitectural parameters of the trabecular and the cortical compartment. Bone mineral density distribution and osteocyte lacunar parameters were quantified using quantitative backscattered electron imaging in periosteal, endocortical, and trabecular regions. Additionally, cortical hardness and Young's modulus were assessed by nanoindentation. While cortical porosity strongly increased with age independent of sex, trabecular microarchitecture remained stable. Notably, nearly half of the specimens showed non-bony hypermineralized tissue located at the periosteum, similar to that previously detected in the femoral neck, with no consistent association with advanced age. Independent of this finding, cortical and trabecular mineralization, i.e., mean calcium content, as well as endocortical tissue hardness increased with age in males but not females. Importantly, we also observed mineralized osteocyte lacunae that increased with age specifically in females. In conclusion, our results indicate that skeletal aging of the distal fibula is signified not only by pronounced cortical porosity but also by an increase in mineralized osteocyte lacunae in females. These findings may provide an explanation for the increased occurrence of ankle fractures in older women.

An imageology-based feasibility study of plating posterolateral tibial plateau fractures via an anterolateral trans-fibular-head approach.

BACKGROUND: There are many difficulties in the reduction and fixation of the tibial plateau fractures involving posterolateral quadrant using general plates via traditional approaches. By imaging the area above the fibulae capitulum, this study was performed to investigate the feasibility of the trans-fibular-head approach and to design an ideal anatomical plate. METHODS: MRI and CT scans of the knee joint were collected from 205 healthy volunteers (103 males, 102 females). Gender and height were used to divide the volunteers into groups separately: (1) A1 group and A2 group according to gender, (2) B1 group and B2 group according to height. Based on the images, several parameters were defined and measured to describe the space above the head of the fibula. In addition, differences in these parameters between genders and height were compared. RESULTS: The narrowest distance in the bony region was (10.96 ± 1.39) mm, (5.41 ± 0.97 mm) in the bone-ligament region. The narrowest distance of bony region in the A1 group was more than that in the A2 group (11.21 ± 1.62 mm, 10.85 ± 1.47 mm, p = 0.029). The narrowest distance of the bony region was (10.21 ± 1.42) mm and (11.65 ± 1.39) mm in the B1 group and B2 group, respectively (p = 0.002). The narrowest distance of the bone-ligament region was (5.39 ± 0.78) mm and (5.22 ± 1.21) mm in the A1 group and A2 group, respectively. No statistically significant differences were observed between the A1 group and the A2 group in terms of the narrowest distance of the bone-ligament region. In the B1 group, the narrowest distance of the bone-ligament region (5.18 ± 0.71 mm) was not significantly less than that (5.31 ± 0.91 mm) in the B2 group. CONCLUSION: The space above the fibular capitellum was ample enough to place the plate for treating tibial plateau fractures involving posterolateral quadrant. The divisions of the lateral tibial plateau by 3-dimensional CT and the parameters of each region were crucial for providing guidance for designing the anatomical plate for the trans-fibular-head approach.

Image Rotation Alters Apparent Fibula Length: An Evaluation of Talocrural Angle, Shenton Line, and Dime Sign.

BACKGROUND: Fibula shortening can compromise ankle stability and force transmission, thereby impacting clinical outcomes. Because radiographs depict 3-dimensional anatomy in 2 dimensions, accurate radiographic assessment of fibula length is a commonly encountered clinical challenge. The talocrural angle (TCA), Shenton line, and dime sign are useful parameters of fibula length. Yet, the impact of 3-dimensional limb positioning on these radiographic parameters is not established. METHODS: Bone models were constructed from CT scans of 30 lower limbs. Fibula length was computationally manipulated, and digitally reconstructed radiographs were generated reflecting 1-degree increments of sagittal and axial plane rotation of each limb for each fibula length condition. The TCA was computationally measured on each image. The presence of an aligned mortise view, intact Shenton line, and intact dime sign was assessed by 2 observers. RESULTS: The mean TCA, which was 78.0 (95% CI ± 1.6) degrees for a true mortise projection with anatomic fibula length, changed by approximately 1 degree per millimeter of fibula length change. On average, 14.7 degrees of caudal rotation obscured 2 mm of fibular shortening by virtue of producing the same TCA as a true mortise view with anatomic fibula length, designated a false positive view. Axial rotation had a comparatively small effect. Observers 1 and 2 were, respectively, 91% and 88% less likely to accurately judge the image alignment of the false positive images compared to true mortise images. Moreover, intraobserver agreement was poor to moderate (mean 0.47, range 0.13-0.59) and interobserver agreement was uniformly poor (mean 0.08, range 0.01-0.20). CONCLUSION: In our study using digitally reconstructed radiographs from CT scans of 30 limbs, we found that sagittal plane rotation impacts the radiographic appearance of fibula length as measured by the TCA. Limb axial rotation had a comparatively small effect. Further study of human perception of Shenton line and dime sign is needed before the effect of rotation on these parameters can be fully understood. LEVEL OF EVIDENCE: Level IV, case series.

Pachydysostosis of the fibula in a case of familial adenomatous polyposis.

BACKGROUND: Familial Adenomatous Polyposis (FAP) is a colorectal cancer (CRC) predisposition syndrome caused by germline APC mutations and characterised by an increased risk of CRC and colonic polyps and, in certain forms, of specific prominent extraintestinal manifestations, namely osteomas, soft tissue tumours and dental anomalies. Pachydysostosis of the fibula is a rare clinical entity defined by unilateral bowing of the distal portion of the fibula and elongation of the entire bone, without affectation of the tibia. CLINICAL REPORT: We report a 17-year-old male, who presented with a non-progressive bowing of the right leg detected at 18 months of age caused by a fibula malformation (later characterized as pachydysostosis) and a large exophytic osteoma of the left radius, noticed at the age of 15 years, without gastrointestinal symptoms. There was no relevant family history. Detailed characterisation revealed multiple osteomas, skin lesions and dental abnormalities, raising the hypothesis of FAP. This diagnosis was confirmed by genetic testing [c.4406_4409dup p.(Ala1471Serfs*17) de novo mutation in the APC gene] and endoscopic investigation (multiple adenomas throughout the colon, ileum and stomach). DISCUSSION: This case report draws attention to the phenotypic spectrum of skeletal manifestations of FAP: this patient has a congenital fibula malformation, not previously associated with this syndrome, but which is likely to have been its first manifestation in this patient. This clinical case also illustrates the challenges in the early diagnosis of FAP, especially without family history, and highlights the importance of a multidisciplinary approach and the adequate study of rare skeletal abnormalities.

Ultrasound Assessment of Ankle Syndesmotic Injuries in a Pediatric Population.

OBJECTIVE: To determine sensitivity and specificity for anterior-inferior tibiofibular ligament (AiTFL) integrity and tibiofibular clear-space (TFCS) cut-off points for dynamic evaluation using ultrasound (US) in a pediatric population. DESIGN: Prospective cohort study. SETTING: Tertiary care university-affiliated pediatric hospital patients between the ages of 12 and 18 sustaining acute ankle trauma with syndesmotic injury. INTERVENTIONS: Participants were assigned to the syndesmotic injury protocol that included a standardized MRI and US. MAIN OUTCOME MEASURES: Anterior-inferior tibiofibular ligament integrity for static assessment and TFCS measurements for dynamic assessment on US. For dynamic assessment, the distance between the distal tibia and fibula was first measured in neutral position and then in external rotation for each ankle. The US results on AiTFL integrity were compared with MRI, considered as our gold standard. Optimal cut-off points of TFCS values were determined with receiver operating characteristics curve analysis. RESULTS: Twenty-six participants were included. Mean age was 14.8 years (SD = 1.3 years). Sensitivity and specificity for AiTFL integrity were 79% and 100%, respectively (4 false negatives on partial tears). For dynamic assessment, the cut-off points for the differences in tibiofibular distance between the 2 ankles in 1) neutral position (TFCS N I-U ) and 2) external rotation (TFCS ER I-U ) were 0.2 mm (sensitivity = 83% and specificity = 80%) and 0.1 mm (sensitivity = 83% and specificity = 80%), respectively. CONCLUSIONS: Static US could be used in a triage context as a diagnostic tool for AiTFL integrity in a pediatric population as it shows good sensitivity and excellent specificity.

Predictive value of clinical features and CT radiomics in the efficacy of hip preservation surgery with fibula allograft.

BACKGROUND: Despite being an effective treatment for osteonecrosis of the femoral head (ONFH), hip preservation surgery with fibula allograft (HPS&FA) still experiences numerous failures. Developing a prediction model based on clinical and radiomics predictors holds promise for addressing this issue. METHODS: This study included 112 ONFH patients who underwent HPS&FA and were randomly divided into training and validation cohorts. Clinical data were collected, and clinically significant predictors were identified using univariate and multivariate analyses to develop a clinical prediction model (CPM). Simultaneously, the least absolute shrinkage and selection operator method was employed to select optimal radiomics features from preoperative hip computed tomography images, forming a radiomics prediction model (RPM). Furthermore, to enhance prediction accuracy, a clinical-radiomics prediction model (CRPM) was constructed by integrating all predictors. The predictive performance of the models was evaluated using receiver operating characteristic curve (ROC), area under the curve (AUC), DeLong test, calibration curve, and decision curve analysis. RESULTS: Age, Japanese Investigation Committee classification, postoperative use of glucocorticoids or alcohol, and non-weightbearing time were identified as clinical predictors. The AUC of the ROC curve for the CPM was 0.847 in the training cohort and 0.762 in the validation cohort. After incorporating radiomics features, the CRPM showed improved AUC values of 0.875 in the training cohort and 0.918 in the validation cohort. Decision curves demonstrated that the CRPM yielded greater medical benefit across most risk thresholds. CONCLUSION: The CRPM serves as an efficient prediction model for assessing HPS&FA efficacy and holds potential as a personalized perioperative intervention tool to enhance HPS&FA success rates.

Radiological landmark of syndesmotic ligament complex by magnetic resonance imaging correlate with fibula free flap harvesting procedure.

Preservation of syndesmotic ligaments is crucial for preventing adverse sequelae at the donor site following free fibula osteocutaneous flap harvesting. This study sought to determine the relationship between distal tibiofibular ligaments and the fibular segment to identify radiological landmarks that facilitate safe and precise flap. The distances between the distal tibiofibular ligaments (anterior inferior tibiofibular ligament [AITFL], posterior inferior tibiofibular ligament [PITFL]) and the fibular segment, as well as the lower border of the interosseous membrane, were measured on magnetic resonance imaging (MRI) scans of 296 patients without any perceivable ankle abnormalities. The mean distances (± SD) between the distal end of the fibula and the AITFL, PITFL, and lower interosseous membrane border were 3.0 ± 0.4 cm, 2.6 ± 0.4 cm, and 3.9 ± 0.6 cm, respectively. The distance between the talar dome and the PITFL exhibited a range of 0.0-0.5 cm. Our findings support preserving a distal fibular remnant of at least 4 cm to avoid injury to the syndesmotic ligament throughout fibula osteocutaneous flap harvesting. The talar dome could serve as a useful radiological landmark for identifying the upper border of PITFL during preoperative evaluation, and thus facilitating precise and safe flap procurement.

Comparison of different fibula procedures in tibiotalocalcaneal arthrodesis with a retrograde intramedullary nail: a mid-term retrospective study.

BACKGROUND: Tibiotalocalcaneal (TTC) arthrodesis with a retrograde intramedullary nail for severe tibiotalar and talocalcaneal arthritis has a high fusion rate; however, no studies have focused on how to handle the fibula intraoperatively to achieve better results. This study aimed to compare the efficacies of various fibular procedures. METHODS: We retrospectively reviewed the cases of severe tibiotalar and talocalcaneal arthritis in adults treated with TTC arthrodesis using a retrograde intramedullary nail between January 2012 and July 2017. The patients were divided into three groups according to different fibular procedures: Fibular osteotomy (FO), fibular strut (FS), and fibular preservation (FP). Functional outcomes and pain were assessed using the American Orthopedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and visual analog scales (VAS), respectively. The operation time, fusion time, radiographic evaluation, and complications were also recorded. RESULTS: Fifty-eight patients with an average age of 53.2 (range, 32-69) years were enrolled in the final analysis. The numbers of patients enrolled in the three groups were 21, 19, and 18 in the FO, FS, and FP groups, respectively. The mean postoperative follow-up time was 66.0 (range, 60-78) months. All groups showed a high fusion rate (90.5% for FO, 94.7% for FS, and 94.4% for FP) and significant improvement in AOFAS ankle and hindfoot scores and VAS scores at the latest follow-up. There were no significant differences in these parameters among the three groups. The mean operation time of FS (131.3 ± 17.1 min) was longer than that of FO (119.3 ± 11.7 min) and FS (112.2 ± 12.6 min), but the fusion time was shorter (15.1 ± 2.8 weeks for FS, 17.2 ± 1.9 weeks for FO, and 16.8 ± 1.9 weeks for FP). Statistically significant differences were observed in these parameters. CONCLUSIONS: TTC arthrodesis using a retrograde intramedullary nail is an effective procedure with a high rate of fusion to treat severe tibiotalar and talocalcaneal arthritis in adults; however, FSs can shorten fusion time when compared with FO and FP. LEVEL OF CLINICAL EVIDENCE: Level 3.

Automatic segmentation of inconstant fractured fragments for tibia/fibula from CT images using deep learning.

Orthopaedic surgeons need to correctly identify bone fragments using 2D/3D CT images before trauma surgery. Advances in deep learning technology provide good insights into trauma surgery over manual diagnosis. This study demonstrates the application of the DeepLab v3+ -based deep learning model for the automatic segmentation of fragments of the fractured tibia and fibula from CT images and the results of the evaluation of the performance of the automatic segmentation. The deep learning model, which was trained using over 11 million images, showed good performance with a global accuracy of 98.92%, a weighted intersection over the union of 0.9841, and a mean boundary F1 score of 0.8921. Moreover, deep learning performed 5-8 times faster than the experts' recognition performed manually, which is comparatively inefficient, with almost the same significance. This study will play an important role in preoperative surgical planning for trauma surgery with convenience and speed.

Impact of the adjacent bone on pseudarthrosis in mandibular reconstruction with fibula free flaps.

BACKGROUND: Mechanical and morphological factors have both been described to influence the rate of pseudarthrosis in mandibular reconstruction. By minimizing mechanical confounders, the present study aims to evaluate the impact of bone origin at the intersegmental gap on osseous union. METHODS: Patients were screened retrospectively for undergoing multi-segment fibula free flap reconstruction of the mandible including the anterior part of the mandible and osteosynthesis using patient-specific 3D-printed titanium reconstruction plates. Percentage changes in bone volume and width at the bone interface between the fibula/fibula and fibula/mandible at the anterior intersegmental gaps within the same patient were determined using cone-beam computed tomography (CBCT). Additionally, representative samples of the intersegmental zones were assessed histologically and using micro-computed tomography (µCT). RESULTS: The bone interface (p = 0.223) did not significantly impact the change in bone volume at the intersegmental gap. Radiotherapy (p < 0.001), time between CBCT scans (p = 0.006) and wound healing disorders (p = 0.005) were independent risk factors for osseous non-union. Preliminary analysis of the microstructure of the intersegmental bone did not indicate morphological differences between fibula-fibula and fibula-mandible intersegmental bones. CONCLUSIONS: The bone interface at the intersegmental gap in mandibular reconstruction did not influence long-term bone healing significantly. Mechanical and clinical properties seem to be more relevant for surgical success.

Proximal fibular axis is a reliable landmark for tibial coronal alignment in patients with or without knee osteoarthritis: A radiological comparative study.

BACKGROUND: Proper coronal alignment of the limb is of vital importance in the progression of knee osteoarthritis even in the long-term survivorship of component after total knee arthroplasty (TKA). Nevertheless, to the best of our knowledge, the relationship between coronal fibular axis and tibial mechanical axis had not reached a consensus in the literatures available. The current study aimed to explore the anatomic relationship between tibia and fibula alignment. METHODS: A total of 100 patients with knee osteoarthritis scheduled for total knee arthroplasty were enrolled in this study (Group A), and radiographic measurement was compared to a control group of 100 healthy volunteers without knee osteoarthritis (Group B). Full-length standing hip-to-ankle radiographs were used to assess limb alignment. The angle between coronal proximal fibular anatomic axis and tibia mechanical axis (PFTA) was used to represent the anatomic relationship between tibia and fibula alignment. A negative value indicates fibula varus relative to tibia mechanical axis, while a positive value indicates fibula valgus. RESULTS: The mean PFTAs were -0.9° ± 0.9° and -1.0° ± 0.8° in Groups A and B. There was no significant difference between the two groups. No significant difference was detected in PFTA distribution in the group A and B. When the mean value of PFTA is used as baseline data, the percentage of subjects in which the PFTA deviation was within 0.5°, 1°, and 1.5° was 51%, 84%, and 94% in Group A and 53%, 87%, and 96% in Group B. There was also no significant difference in distribution deviation between the two groups. No patient-specific factors were correlated with the PFTA. CONCLUSIONS: The proximal fibular anatomic axis is a reliable landmark for tibial mechanical axis in the coronal plane in patients with or without knee osteoarthritis.

Does Fibular Displacement Predict Tibial Malrotation in Simulated Tibia-Fibula Fractures.

INTRODUCTION: Tibial malrotation can occur with medullary nailing of diaphyseal tibial fractures. Fibular alignment has been proposed as a surrogate for axial plane reduction intraoperatively. The purpose of this study was to determine whether fibular alignment is a reliable marker of accurate tibial rotation. METHODS: Deidentified CT scans of 50 patients with normal tibial anatomy were selected. Using ImageJ software, we simulated osteotomies at three sites (proximal third, mid-diaphysis, and distal third). We overlaid adjacent CT slices and rotated them around the central axis of the tibia in 5° increments of external rotation (ER) and internal rotation (IR). At each increment, measurements of fibular overlap (%) were obtained from anteroposterior (AP) and lateral views. To simulate fixation of the fibula, we repeated rotation around the axis of the fibula with and without a simulated medullary implant in the tibia. RESULTS: A total of 50 patients were included. The mean age was 62 years, average BMI was 25.8, and 28 of 50 patients (56%) were male. Earliest loss of fibular contact occurred at 24° ER and 22° IR at the proximal site. Contact was lost at 26° ER and 28° IR on the AP view and 42° ER and 29° IR on the lateral view. The mean fibular contact at each 5° increment was similar for ER and IR. Fibular contact was reduced to 50% at 10 to 15° of rotation in ER and IR at all sites. Tibial canal contact was lost at 24° in both ER and IR around the fibula. With a virtual medullary implant, the mean maximal rotation was 6°. DISCUSSION: Surgeons should be aware that 20° or more of malrotation is likely present when fibular contact is lost during medullary nailing of the tibia. Greater than 50% loss of contact should raise suspicion for malrotation. A fixed fibula and medullary tibial implant theoretically preclude significant tibial malrotation.

Reconstruction of complicated spinal tuberculosis with long-segment fibula transplantation: a case report.

BACKGROUND: Treating complex cases of spinal tuberculosis (STB) that involve multiple vertebral bodies and cause destruction of the spinal structure, kyphotic deformity, and acute nerve injury can be challenging. This report describes the course of treatment and 5-year follow-up of a complex case of multisegmental STB. CASE PRESENTATION: This report describes a case of tuberculosis affecting the vertebrae extending from thoracic 12 to lumbar 5 in a 60-year-old woman who suffered sudden paralysis in both lower extremities. The patient underwent emergency posterior paraspinal abscess clearance, laminectomy with spinal decompression. Partial correction of the kyphotic deformity via long-segment fixation from the T9 vertebral body to the ilium in a one-stage posterior procedure. The patient's neurological status was diagnosed as grade E on the American Spinal Injury Association (ASIA) scale after the one-stage operation. Following standardized 4-combination anti-tuberculosis drug therapy for three months in postoperative patients, the patient underwent two-stage transabdominal anterior abscess removal, partial debridement of the lesion and bilateral fibula graft support. One year after the two-stage operation, the patient's visual analog scale (VAS) score of back pain was 1 point, and the patient's erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels returned to normal. Five years after the second-stage operation, the Oswestry disability index (ODI) of patient quality of life was 14 points. There was a 4-degree change in the Cobb angle over five years. During the five-year follow-up period, the grafted fibula did not experience any subsidence. CONCLUSION: For patients with spinal tuberculosis and acute paralysis, it is essential to relieve spinal cord compression as soon as possible to recover spinal cord function. For lesions that cannot be debrided entirely, although limited debridement combined with anti-tuberculosis drug therapy has the risk of sinus formation and tuberculosis recurrence, it is much safer than the risk of thorough debridement surgery. In this case, an unconventional long-segment fibula graft, pelvis-vertebral support, was an effective reconstruction method.

Pediatric Peroneal Nerve Palsy Secondary to Fibular Osteochondroma.

Peripheral nerve injuries due to mass effect from bony lesions can occur when the nerve exists in an anatomically constrained location, such as the common peroneal nerve at the fibular head which passes into the tight fascia of the lateral leg compartment. We report a case of a pediatric patient who developed a common peroneal nerve palsy secondary to an osteochondroma of the fibular head and describe the clinical evaluation, radiographic findings, and surgical approach. Rapid diagnosis and nerve decompression after the onset of symptoms restored full motor function at the 8-month postoperative mark.

Fibular Fixation in Same-Level Distal Third Tibiofibular Fractures: Is Fibular Fracture Regarded as a Secondary Importance?

Background: Although most studies focused on the alignment or union of the tibia in same-level distal third tibiofibular fractures, the outcome of a concomitant fibular fracture is generally regarded as being of secondary importance in the literature. This study aimed to assess the outcomes of fibular fractures in same-level distal third tibiofibular fractures. Methods: In this retrospective study, we enrolled 111 patients with same-level distal third tibiofibular fractures treated at our institute between January 2016 and August 2020. Tibial fractures were stabilized with intramedullary nailing, and the cases were divided into two groups based on whether they additionally underwent fibular fixation (group 1, 57 cases) or not (group 2, 54 cases). Clinical and radiographic outcomes were used for the evaluation of tibial and fibular alignments, union of the tibia and fibula, number of interlocking screws in the distal tibial fragment, range of motion of the ankle joint, and complications. Results: No statistically significant differences in the tibial union rate or mean tibial alignment were observed between the two groups on either the immediate postoperative or final radiographs. The fibular union rate in group 1 was significantly higher than that in group 2 (fibular nonunion, 0 vs. 15; p < 0.001). Statistically significant differences in fibular displacement were observed on immediate postoperative radiographs between patients with fibular union and those without it. At the final follow-up, the mean range of ankle motion and lower extremity functional scale scores did not differ between the two groups. Conclusions: Regardless of whether fibular fixation was performed, the overall tibial alignment with intramedullary nailing was well restored and the union rate of the tibia was comparable in the two groups. Fibular nonunion is not uncommon in unfixed fibula fractures. Displacement of the fibula as seen on immediate postoperative radiographs was related to fibular nonunion.

The safe zone of distal fibula was determined based on the classification of lateral malleolus fossa.

BACKGROUND: Lateral malleolus fractures are very common, and the distal fibular geometry is complex. This study aimed to classify the lateral malleolus fossa (MF) into different types by characterizing the lateral MF imaging morphology and exploring the relationship between the lateral MF and internal fixation position after distal fibula fractures. METHODS: Anteroposterior CT reconstruction was performed on 248 subjects. After reconstruction, the deepest point of the lateral MF was located, and then, the cross-sectional shape of the lateral MF was observed and classified. RESULTS: According to the morphology of the CT cross section, the lateral MF was divided into three types: type C (43.1%), type V (32.2%), and type Flat (24.7%). Type V (3.98 ± 0.82) was significantly longer than type C(2.83 ± 0.54) and type Flat (1.84 ± 0.42) in cd. Similarly, in ∠α, Type Flat(136.31 ± 9.63) was the largest, followed by type C (116.51 ± 8.79), and type V (89.31 ± 9.07) was the smallest. Other measurements were not found any significant differences between the above. CONCLUSION: According to the morphology of the CT cross section, the lateral MF was divided into three types: type C, type V and type Flat. Type V is most likely to be invaded when fixing the distal fibula. Screws less than 9 mm should be selected when fixing, and screws no more than 10 mm should be selected when there are type C and type Flat of MF.

The lowest point of fibula (LPF) could be used as a reliable bony landmark for arthroscopic anchor placement of lateral ankle ligaments ----compared with open Broström procedure.

BACKGROUND: Arthroscopic technique procedures was wide accepted for the treatment of chronic ankle instability (CAI). But little acknowledge was involved to the bony landmarks and anatomic features of different bundles of lateral ligaments under arthroscopic view. METHODS: Sixty patients with acute or chronic lateral ankle ligaments injury (LAI) were collected prospectively, and divided randomly into two groups. In arthroscopic group, the bone tunnels were made on the LPF arthroscopically. And in open group, the bone tunnels were made on the Fibular obscure tubercle (FOT) in open procedure. The inferior bundle of ATFL and Arcuate fibre was also identified reference to the LPF and labeled by a PDS II suture penetration. Following that, The distances of the bone tunnels to the different bony markers were measured and compare between two groups. The penetrating locations of PDS II on the inferior bundle of ATFL and Arcuate fibre were also confirmed intraoperatively. And the safe angle of anchor implantation on the axial view was measured on postoperative CT scan. RESULTS: The distances of bone tunnel to the fibular tip, the fibular insertion of anterior-inferior tibiofibular ligament (AITFL), and the FOT in arthroscopic and open locating groups were 4.9 ± 2.2 and 6.3 ± 2.2 mm, 13.5 ± 2.7 and 12.4 ± 1.1 mm, 5.8 ± 2.2 and 5.6 ± 1.0 mm, respectively. The distances of bone tunnels to the FOT and fibular tip on 3d-CT view was 4.4 ± 1.5 and 4.6 ± 0.9 mm, 14.4 ± 3.2 and 13.2 ± 1.8 mm in arthroscopic and open group, and there were no significant differences between two groups. The safe angle of arthroscopic anchor placement on the axial plan was ranged from 24.9 ± 6.3o to 58.1 ± 8.0o. The PDS II sutures penetrating on the inferior bundles of ATFL and the arciform fibres were also comfirmed successfully by open visualizaion.The average distance of penetration point to the horizontal line cross the fibular tip was 2.3 ± 2.7 mm (ranged from - 3.1 to 6.0 mm), and to the vertical line cross the FOT was 2.7 ± 2.7 mm (ranged from - 2.5 to 7.5 mm). CONCLUSION: Take the lowest point of fibula under arthroscopy (LPF) as a bony reference, we could identify the iATFL under arthroscopic visualization. By this way, we could place the suture anchors properly to the fibular footprint and suture the iATFL fibres successfully.