Evaluation of Accuracy of Preoperative Planning of the Femurofibular Angle in Open-Wedge High Tibial Osteotomy for Mild Medial Knee Osteoarthritis.

OBJECTIVE: The purpose of this study was to evaluate the usefulness of preoperative planning of the femurofibular angle (FFA) in medial open-wedge high tibial osteotomy (OWHTO) for mild medial knee osteoarthritis. METHODS: Thirty-two patients (32 knees) with mild medial knee OA were retrospectively reviewed. The patients underwent preoperative planning of the FFA for OWHTO. For preoperative planning, a full-length weight-bearing X-ray photograph of the lower limb was opened within Adobe Photoshop Software, and a targeted corrective mechanical axis line of the lower limb and its intersecting point at the lateral tibial plateau surface was drawn using rectangle selection and filling tools. A frame, which encircled the tibia and fibula, was created around the predicted osteotomy plane and then rotated until the ankle center was on the targeted mechanical axis line. Subsequently, a distal femoral condyle line and a proximal fibula axis line were drawn, and the angle between the two lines was measured and defined as the femurofibular angle (FFA). During biplane OWHTO, the preoperatively determined FFA was used to complete the correction of the mechanical axis. During follow-up, the postoperative mechanical weight-bearing line (WBL) of the lower limb, the mechanical femorotibial angle (mFTA), and the FFA were measured and compared with the preoperatively determined values. RESULTS: The mechanical WBL shifted from a preoperative value of 25.36 ± 5.02% to a postoperative value of 56.19 ± 0.10% from the medial border along the mediolateral width of the tibial plateau, and it was 56.57 ± 0.08% at the final follow-up (P < 0.01). The preoperatively determined value was 56.25%, and no significant difference was found compared with postoperative week-one and final follow-up values (P > 0.05). The mFTA was corrected from a preoperative varus of 4.02 ± 0.63° to a postoperative week-one valgus of 2.37 ± 0.28°, and it had a valgus of 2.48 ± 0.39° at the final follow-up (P < 0.01). No significant difference in the valgus was found compared with the postoperative week-one, final follow-up and preoperatively determined valgus of 2.34 ± 0.26° (P > 0.05). The postoperative week-one and final follow-up FFAs were 90.34 ± 1.53° and 90.33 ± 1.52°, respectively, and no significant difference was found compared with the preoperatively determined value of 90.12 ± 1.72° and the intraoperative setting value of 90.25 ± 1.67° (P > 0.05). All corrected values were within the acceptable range of preoperative planning. CONCLUSION: Preoperative planning of the FFA may be useful in OWHTO for patients with mild medial knee OA. Satisfactory correction of the postoperative targeted mechanical axis line of the lower limb can be obtained.

The fibula and talus position difference in functional and mechanical ankle instability: MRI findings.

PURPOSE: This study aimed to use MRI to evaluate the fibula and talus position difference in functional and mechanical ankle stability patients. METHODS: 61 and 68 patients with functional and mechanical instability, and 60 healthy volunteers were involved. Based on the axial MRI images, the rotation of the talus was identified through the Malleolar Talus Index (MTI). The position relative to the talus (Axial Malleolar Index, AMI) and medial malleolus (Intermalleolar Index, IMI) were used to evaluated the displacement of the fibula. RESULTS: Post hoc analysis showed that the values of malleolar talus index was significantly larger among mechanical instability (89.18° ± 2.31°) than that in functional instability patients (86.55° ±61.65°, P < 0.001) and healthy volunteers (85.59° ± 2.42°, P < 0.001). The axial malleolar index of the mechanical instability patients (11.39° ± 1.41°) were significantly larger than healthy volunteers (7.91° ± 0.83°) (P < 0.0001). There were no statistically significant differences in the above three indexes between the functional instability patients and healthy volunteers. CONCLUSION: The functional instability patients didn't have a posteriorly positioned fibula and an internally rotated talus. The malleolar talus index was significantly larger among mechanical instability patients than that in functional instability patients. Increased malleolar talus index may become a new indirect MRI sign for identifying functional and mechanical instability patients.

Arthroscopic coronal plane syndesmotic instability has been over-diagnosed.

PURPOSE: Ankle arthroscopy is widely used for diagnosis of syndesmotic instability, especially in subtle cases. To date, no published article has systematically reviewed the literature in aggregate to understand which instability values should be used intraoperatively. The primary aim was to systematically review the amount of tibiofibular displacement that correlates with syndesmotic instability after a high ankle sprain. A secondary aim is to assess the quality of such research. METHODS: Systematic searches of EMBASE (Ovid) and MEDLINE via PubMed, CINAHL, Web of Science, and Google Scholar were used. INCLUSION CRITERIA: studies that arthroscopically evaluated the fibular displacement at various stages of syndesmotic ligament injury. Two reviewers independently extracted data and assessed methodological quality using the Anatomical Quality Assessment (AQUA) Tool and methodological index for non-randomized studies (MINORS). RESULTS: Eight cadaveric studies and three clinical studies were included for review. All studies reported displacement in the coronal plane, four studies reported in the sagittal plane, and one reported findings in the rotational plane. Four cadaveric studies had a similar experimental set up and the weighted mean associated with instability in the coronal plane could be calculated and was 2.9 mm at the anterior portion of the distal tibiofibular joint and 3.4 mm at the posterior portion. Syndesmotic instability in the sagittal plane is less extensively studied, however available data from a cadaveric study suggests thresholds of 2.2 mm of posterior fibular translation when performing an anterior to posterior hook test and 2.6 mm of anterior fibular translation when performing a posterior to anterior hook test. CONCLUSIONS: The results have concluded that the commonly used 2.0 mm threshold value of distal tibiofibular diastasis may lead to overtreatment of syndesmotic instability, and that using threshold values of 2.9 mm measured at the anterior portion of the incisura and 3.4 mm at the posterior portion may represent better cut off values. Given the ready availability of 3 mm probes among standard arthroscopic instrumentation, at the very least surgeons should use 3 mm in lieu of 2 mm probes intraoperatively. LEVEL OF EVIDENCE: IV.

Is the Fibular Station on Lateral Ankle Radiographs Symmetric? A Retrospective Observational Radiographic Study.

BACKGROUND: Precise reduction of a syndesmosis after disruption is critical to improve patient physical function. Intraoperative lateral radiographs of the unaffected ankle are often used in clinical practice as a template for anatomic syndesmotic reduction because sagittal plane malreduction is common. However, there is little data to suggest fibular station, or the position of the fibula in the AP plane on the lateral radiograph, is symmetric side-to-side in patients. QUESTIONS/PURPOSES: (1) Is the position of the fibula in the AP plane (fibular station) on lateral ankle radiographs symmetric in an individual? (2) Do the measurements used to judge the position of the fibula on lateral radiographs have good inter- and intraobserver reliability? METHODS: Over the period from August 2016 to October 2018, we identified 478 patients who presented to an orthopaedic clinic with forefoot and midfoot complaints. Skeletally mature patients with acceptable bilateral lateral ankle radiographs, which are common radiographs obtained for new patients to clinic for any complaint, were included. Based on that, 52% (247 of 478 patients) were included with most (22%, 107 patients) excluded for poor lateral radiographs. The most common diagnosis in the patient cohort was midfoot OA (14%, 35 patients). The median (range) age of the included patients was 54 years (15 to 88), and 65% (159 of 247) of the patients were female. Fibular station, defined as the position of the fibula in the AP plane, and fibular length were measured using a digital ruler and goniometer on lateral radiographs. A paired t-test was used to determine if no difference in fibular station existed between the left and right ankles. With 247 paired-samples, with 80% power and an alpha level of 0.05, we could detect a difference between sides of 0.008 for the posterior ratio, 0.010 for the anterior ratio, and 0.012 for fibular length. Two readers, one fellowship-trained orthopaedic traumatologist and one PGY-4, measured 40 patients to determine the inter- and intraobserver reliability by intraclass correlation coefficient (ICC). RESULTS: The posterior fibular station (mean right 0.147 [σ = 0.056], left 0.145 [σ = 0.054], difference = 0.03 [95% CI 0 to 0.06]; p = 0.59), anterior fibular station (right 0.294 [σ = 0.062], left 0.299 [σ = 0.061], difference = 0.04 [95% CI 0 to 0.08]; p = 0.20), and fibular length (right 0.521 [σ = 0.080], left 0.522 [σ = 0.078], difference = 0.05 [95% CI 0.01 to 0.09]; p = 0.87) ratios did not differ with the numbers available between ankles. Inter- and intraobserver reliability were excellent for the posterior ratio (ICC = 0.928 and ICC = 0.985, respectively) and the anterior ratio (ICC = 0.922 and ICC = 0.929, respectively) and moderate-to-good for the fibular length ratio (ICC = 0.732 and ICC = 0.887, respectively). CONCLUSION: The use of lateral radiographs of the contralateral uninjured ankle appears to be a valid template for determining the position of the fibula in the sagittal plane. However, further prospective studies are required to determine the efficacy of this method in reducing the syndesmosis over other methods that exists. LEVEL OF EVIDENCE: Level III, diagnostic study.

How to address the posterior malleolus in ankle fractures? A decision-making model based on the computerised tomography findings.

INTRODUCTION: The posterior malleolus (PM) is affected in around the 40% of ankle fractures. Anatomical reduction of the articular surface and fibular notch are essential for ankle stability and functional outcomes. These facts justify the increasing interest in the surgical treatment of PM in ankle fractures. Within this context, pre-operative computed tomography (CT) images and posterior approaches to the ankle play a crucial role. The aim of this paper is to make an accurate description of the literature and describe, according to authors' experience, the best surgical approach to the PM based on the CT findings while assessing their advantages and disadvantages. METHODS: The fracture pattern of PM is classified according to Haraguchi or Bartonícek classification, both based on pre-operative CT scan images. The posterolateral (PLA) and posteromedial (PMA) approaches to the ankle and their corresponding modifications are described. We propose a decision-making algorithm for posterior malleolus fractures to facilitate treatment selection. RESULTS: Posterolateral approach should be the election for Haraguchi I or III and Bartonícek 1, 2, or 4 fractures. Percutaneous PLA might be adequate in Haraguchi I and Bartonícek 1 to improve syndesmotic stability. In PL approaches, the fibula fracture may be addressed and fixed with a posterolateral plate or through a subcutaneous window that allows lateral reduction and fixation. Posteromedial approach should be the election for Haraguchi II and Bartonícek 3 fractures. A modified PMA might be the election to reduce and fix any fragment dependent on the anterior inferior tibiofibular ligament (AITFL). The modified PMA is performed in a supine position and allows us to check the articular reduction under direct vision. Both PMA are associated with a lateral fibular approach. CONCLUSION: To address the posterior malleolus when treating ankle fractures, surgeons should choose the most adequate approach based on the fracture pattern and their own experience. Anatomical reduction and stable fixation are critical to improve outcomes.

Fibular-Lengthening Osteotomy in Patient with Progressive Valgus Deformity After an Ankle Fracture.

BACKGROUND The fibular fracture requires an anatomical reduction. When a malunion occurs, it can lead to a valgus deformity with an opening of the ankle mortise. CASE REPORT This case deals with a 23-year-old patient with pain and limited movement in the right ankle, caused by a fracture healed in an incorrect position, with shortening of the fibula and progressive displacement of the valgus, after surgery 12 months earlier for an ankle fracture. The patient underwent a corrective procedure consisting of extemporaneous lengthening of the fibula, with interposition of autologous bone graft and fixation using a compression plate. Six months after surgery, the patient did not present pain or limited movement, and was able to return to his habitual sporting activity. CONCLUSIONS Fibular-lengthening osteotomy is a procedure indicated for patients with malunion fracture of the distal fibula, with shortening and progressive valgus deformity. This surgery allows the restoration of the joint surface, reduces stress on the cartilage and prevents the development of arthropathy of the ankle.

The fibular shaft axis and medial cortex of the proximal fibula are reliable landmarks for the mechanical axis of the tibia in patients with knee osteoarthritis.

BACKGROUND: This study aimed to evaluate the validity of proximal fibular anatomic landmarks for measuring the coronal tibial mechanical axis in patients with knee osteoarthritis and to investigate individual factors associated with their reliability. METHODS: A total of 106 knees in 96 patients were retrospectively reviewed. The angles between the tibial mechanical axis and fibular shaft axis (TFA), medial cortex of the proximal fibular shaft (MTA), and lateral cortex of the proximal fibular shaft (LTA) were measured from full-leg standing digital anteroposterior radiographs. An angle within three degrees was considered reliable. The association between the above three angles and individual factors, such as age, sex, body mass index (BMI), and varus-valgus knee malalignment, was determined to investigate individual factors associated with their reliability. RESULTS: The median TFA, MTA, and LTA were 1.52°, 1.56°, and 2.62°, respectively. The reliability rates of TFA, MTA, and LTA were 73.6% (95% CI: 65.19-81.98%), 82.1% (74.77-89.38%), and 58.5% (49.11-67.87%), respectively. The reliability of TFA and MTA was not associated with individual variables. The reliability of LTA was associated with BMI. Among patients with BMI greater than 25.3 kg/m2, LTA was considered reliable in 65.7%; this rate was significantly higher than that among patients with BMI less than 25.3 kg/m2. CONCLUSIONS: The fibular shaft axis and medial cortex of the proximal fibular shaft are reliable landmarks of the mechanical axis of the tibia. However, the reliability of the lateral cortex of the proximal fibular shaft is less satisfactory, especially in patients with BMI less than 25.3 kg/m2.

Does fracture obliquity in Weber B fibula fractures correlate with mortise instability?

BACKGROUND: The diagnosis of instability in the apparent, isolated distal fibula fracture can be challenging and often necessitates stress radiography. Danis & Weber classified lateral malleolar fractures based on the level of the fracture in relation to the syndesmosis. While Weber B fractures occur at the level of the syndesmosis, some such injuries present with a long, oblique pattern extending well above the syndesmosis. Given the well-established literature demonstrating that fractures above the syndesmosis correlate with a higher level of concomitant syndesmotic and deltoid ligament injury, we hypothesize that increased fracture obliquity, length and height of Weber B fibula fractures similarly correlates with increased mortise instability. METHODS: All patients with isolated Weber B fibula fractures who underwent gravity stress radiography met inclusion criteria. Fracture height was measured on mortise radiographs as: (1) the distance from the distal tip of the fibula to fracture apex, (2) the distance to the fracture apex as measured on a line drawn perpendicular to a line parallel to the plafond, (3) an angle subtended by a line drawn parallel to the plafond and a line drawn to the fracture apex and (4) a ratio of the absolute length as compared to fibular width. RESULTS: 51 patients were included in the study. The group of 39 patients with stable ankles had a mean medial clear space of 3.12 ±â€¯0.65 mm (range, 1.5 mm to 4.0 mm). The group of 12 patients with unstable ankles had a mean medial clear space of 6.29 ±â€¯3.11 mm (range, 4.1 mm to 14.0 mm). These groups showed no significant difference in fracture angle (p = 0.93), fracture height from plafond (p = 0.49), fracture height from tip of fibula (p = 0.42), and as a ratio of absolute length to fibular width (p = 0.85). CONCLUSION: Increased fracture obliquity, length and height of Weber B fibula fractures did not correlate with a higher incidence of mortise instability. Despite the lack of positive correlation, future studies should continue to investigate and identify radiographic parameters of distal fibula fractures that are most predictive of instability.

Range of Normal and Abnormal Syndesmotic Measurements Using Weightbearing CT.

BACKGROUND: Early recognition of syndesmotic instability is critical for optimizing clinical outcome. Injuries causing a more subtle instability, however, can be difficult to diagnose. The purpose of this study was to evaluate both distal tibiofibular articulations using weightbearing computed tomography (CT) in patients with known syndesmotic instability, thereafter comparing findings between the injured and uninjured sides. We also aimed to define the range of normal measurement variation among patients without syndesmotic injury. METHODS: Patients with unilateral syndesmotic instability requiring operative fixation (n = 12) underwent preoperative bilateral ankle weightbearing CT. A separate cohort of patients without ankle injury who also underwent bilateral ankle weightbearing CT were included as comparative controls (n = 24). For each weightbearing CT, a series of 7 axial plane tibiofibular joint measurements, including 1 angular measurement, were utilized to evaluate parameters of the syndesmotic anatomy at a level 1 cm above the tibial plafond. Values were recorded by 2 independent observers to assess for interobserver reliability. RESULTS: Among those with unilateral syndesmotic instability, values differed between the injured and uninjured sides in 4 of the 7 measurements performed including the syndesmotic area: direct anterior, middle, and posterior differences, and sagittal translation (P < .001, < .001, < .001, and < .001, respectively). In the control population without ankle injury, no differences were identified between any of the bilateral measurements (P value range, .172-.961). CONCLUSION: This study highlights the ability of weightbearing CT to effectively differentiate syndesmotic diastasis among patients with surgically confirmed syndesmotic instability from those without syndesmotic instability. It underscores the substantial utility and importance of using the contralateral, uninjured side as a valid internal control whenever the need for confirming potential syndesmotic instability arises. Prospective studies are necessary to fully understand the accuracy of weightbearing CT in diagnosing occult syndesmotic instability among patients for whom the diagnosis remains in question. LEVEL OF EVIDENCE: Level III, comparative diagnostic study.

Vascular bundle transplantation combined with porous bone substituted scaffold for the treatment of early-stage avascular necrosis of femoral head.

Various reasons leading to disruption of blood supply will result in avascular femoral head necrosis. Decompression of lesion area, structural support to subchondral bone, and rebuilding of blood supply system are the keys for a successful hip preserve surgery. Reconstruction of local vascular network is always a huge challenge in clinical. Based on tantalum rod implantation and free vascularized fibular grafting, we propose the combined application of vascular bundle transplantation and porous bone substitute scaffold implantation as a potential novel treatment method. It may simultaneously achieve decompression, support and blood supply reconstruction. The hypothesis provides some new ideals and possibilities for solving this clinical problem of femoral head necrosis.

Influence of ankle joint position on angles and distances of the ankle mortise using intraoperative cone beam CT: A cadaveric study.

BACKGROUND: The precise anatomical reduction of the ankle mortise is crucial for the clinical outcome in unstable syndesmotic injuries. Intraoperative cone beam computed tomography (CT), in addition to two-dimensional fluoroscopy, provides detailed information about the reduction and implant placement. The aim of this study was to analyze the influence of the joint position on the fibula position in the incisural notch and to determine the inter- and intraindividual anatomical differences in the intact ankle joints. METHODS: A total of 20 fresh-frozen lower legs disarticulated in the knee joint of 10 individuals were included. The measurements were performed using a cone beam CT. The distances and angles were measured in the standard imaging planes. The mean values of distances and angles were compared during the different joint positions: 10° dorsiflexion, 0° neutral position and 20° plantar flexion. RESULTS: The influence of the joint position was on average as follows: The anterior tibiofibular distance was 3.68 mm in 10° dorsiflexion, 3.66 mm (0° neutral position) and 3.59 mm (20° plantar flexion). The posterior tibiofibular distance measured 7.82mm, 7.76mm and 7.82mm. The rotation of the fibula measured ten millimeters proximal the joint line was 1.2°, 1.3° and 1.05°. The fibular rotation determined 4mm was 9.3°, 9.4° and 9.4°. On average, the following intraindividual variations were observed: superior tibiotalar clear space of 0.27mm and 0.15mm medial; and anterior tibiofibular distance of 0.42mm, 0.38mm posterior and 0.24mm in the incisural notch. The proximal angle of the fibular rotation was 0.2° and distal 0.4°. The interindividual variations of the angles and distances exceeded the intraindividual values partly by 3 to 4 fold. CONCLUSIONS: Within the scope of this study neither the tibiofibular distance, nor the tibiofibular angle changed significantly through the different joint positions. The intraindividual differences were little while the interindividual variations of the parameters were distinctive.

Anatomical Adaptation of Fibula and its Mechanism of Proximal Partial Fibulectomy Associated with Medial Compartment Knee Osteoarthritis.

OBJECTIVES: To reveal the anatomical adaptation of the fibula and its relations to age and settlement of the medial tibial plateau, and to explore the mechanism of proximal partial fibulectomy in treating medial compartment knee osteoarthritis (OA). METHODS: A retrospective study was performed in the Third Hospital of Hebei Medical University. Weight-bearing full-leg anteroposterior (AP) radiographs of 280 adults (560 knees) obtained from 1 January 2018 to 31 October 2018 were enrolled according to our inclusion and exclusion criteria, including 157 men and 123 women, with an average age of 50.3 ± 14.8 years (range, 19-80 years). Radiographic severity of knee OA was assessed using Kellgren and Lawrence (K-L) grading. The settlement of the medial tibial plateau was evaluated using the medial proximal tibial angle (MPTA). Curvatures of the tibia and the fibula were measured as proximal tibial curvature (PTC), distal tibial curvature (DTC), proximal fibular curvature (PFC), and distal fibular curvature (DFC). Two orthopaedic surgeons performed all the radiological measurements for 30 randomly selected patients, and repeated the measurements 1 week later. Based on the satisfactory intra-observer and inter-observer reliabilities (ICC > 0.9), each parameter was analyzed in this study. Multivariable linear regression models were used to examine relations between radiological measurements and age. RESULTS: The mean MPTA, PTC, DTC, PFC, and DFC were 85.4° ± 2.8°, 176.2° ± 1.9°, 176.8° ± 1.8°, 176.8° ± 1.9°, and 177.0° ± 2.0°, respectively. Ninety-three knees of K-L grade I were categorized as non-knee OA, and 467 knees of K-L grades II-IV were categorized as knee OA. The MPTA, PTC, and PFC of the knee OA group were significantly smaller than those of non-knee OA group (P < 0.05). The K-L grade of knee OA significantly increased with age (χ 2 = 182.169, P < 0.01). The multivariate linear regression analysis indicated that the MPTA and fibular curvatures were negatively correlated with age (the regression equation is age = 561.165-0.945 MPTA-0.937 PFC-0.959 DFC, P < 0.05), and the MPTA was negatively correlated with PFC (the regression equation is MPTA = 7.827 + 0.099 DFC, P < 0.05). CONCLUSIONS: The proximal curve of the fibula increased in patients with medial compartment knee OA, and this change was positively correlated with age and settlement of the medial tibial plateau. This anatomical adaptation of the fibula was associated with greater fibular axial load and the pulling from the peroneus longus. The proximal partial fibulectomy procedure effected a receptive foot pronation to reduce KAM and rebalance the biceps-proximal fibula-peroneus longus complex, consequently achieving medial compartment unloading.

Changes in ankle joint alignment after proximal fibular osteotomy.

The purpose of this study was to assess the effect of proximal fibular osteotomy (PFO) on ankle joint. 49 patients or 53 lower limbs were included and followed-up with a minimum of one year in the study prospectively. Patients were evaluated radiographically and clinically. The questionnaires of the American Knee Society Score (KSS), the Ankle-Hindfoot Scale of the American Orthopedic Foot and Ankle Society (AOFAS), Visual Analogue Scale/Score (VAS) were used to assess the patients clinically. Radiographic evaluations were measured by the hip-knee-ankle angle (HKA), the femoro-tibial angle (FTA), tibial inclination (TI), distal tibial articural surface (TAS), talar tilt (TT), length of fibular (FL), and hind foot alignment such as hindfoot alignment view angle (HAVA), hindfoot alignment ratio (HAR), and hindfoot moment arm (HMA). Of the 53 subjects, no significant differences were exhibited in AOFAS, VAS scores and FL in ankle joint, but a significant differences were demonstrated in KSS score, HKA, FTA, TI, TT, HAVA, HAR and HMA after PFO. Due to the structural improvements of ankle joint, PFO not only improves joint function but also the alignment of ankle joint radiographically, and is still recommended as a safe surgery in treating medial compartment osteoarthritis of knee.

Achilles Tension Mitigates Fibular Malalignment Measured in Cadaveric Studies of Syndesmotic Clamping.

BACKGROUND:: Fibular malreduction is becoming a commonly recognized complication of surgical repair of the syndesmosis when a reduction clamp is used. The goal of this work was to determine the interdependent effects of transsyndesmotic reduction clamp position and applied compression force on fibular alignment in a realistic cadaveric preparation of complete syndesmotic injury. METHODS:: Six through-the-knee cadaveric specimens were CT scanned intact, with the distal syndesmosis fully destabilized, and with 53, 102, and 160 N clamping forces each applied along an anteriorly, centrally, and posteriorly directed transsyndesmotic axis. Testing was repeated incorporating 178 N of Achilles tendon tension using all 3 clamping forces applied along the centrally directed axis. Fibular reduction was automatically quantified from CT scan-generated bony surfaces as rotation of the fibula around the tibia, rotation of the fibula within the incisura, medial/lateral fibular displacement, and anterior/posterior fibular displacement. RESULTS:: Transsyndesmotic clamping along the anteriorly directed axis resulted in the best reduction quality by all 4 quantified measures. Along the centrally and posteriorly directed axes, progressively greater forces caused significantly greater sagittal plane fibular malreduction. Addition of Achilles tension reduced the magnitude of fibular malreduction and overcompression. CONCLUSION:: Placing the medial tine of a transsyndesmotic reduction clamp on the anterior medial tibia resulted in the most accurate syndesmotic reduction and provided some protection against overcompression with large reduction clamp forces. Achilles tension appeared to contribute to reduction, decreasing the magnitude of measured malreduction from clamping. CLINICAL RELEVANCE:: Previous studies estimating fibular malpositioning in cadaveric models that lacked passive muscle tension may have overestimated expected magnitudes of malalignment in patients treated with syndesmotic clamping. However, syndesmotic malreduction, particularly in the sagittal plane, was a real complication of syndesmotic clamping that was reduced by using an anterior position of the medial tine on the tibia.

The Role of Calcaneofibular Ligament Injury in Ankle Instability: Implications for Surgical Management.

BACKGROUND: Acute inversion ankle sprains are among the most common musculoskeletal injuries. Higher grade sprains, including anterior talofibular ligament (ATFL) and calcaneofibular ligament (CFL) injury, can be particularly challenging. The precise effect of CFL injury on ankle instability is unclear. HYPOTHESIS: CFL injury will result in decreased stiffness, decreased peak torque, and increased talar and calcaneal motion and will alter ankle contact mechanics when compared with the uninjured ankle and the ATFL-only injured ankle in a cadaveric model. STUDY DESIGN: Descriptive laboratory study. METHODS: Ten matched pairs of cadaver specimens with a pressure sensor in the ankle joint and motion trackers on the fibula, talus, and calcaneus were mounted on a material testing system with 20° of ankle plantarflexion and 15° of internal rotation. Intact specimens were axially loaded to body weight and then underwent inversion along the anatomic axis of the ankle from 0° to 20°. The ATFL and CFL were sequentially sectioned and underwent inversion testing for each condition. Linear mixed models were used to determine significance for stiffness, peak torque, peak pressure, contact area, and inversion angles of the talus and calcaneus relative to the fibula across the 3 conditions. RESULTS: Stiffness and peak torque did not significantly decrease after sectioning of the ATFL but decreased significantly after sectioning of the CFL. Peak pressures in the tibiotalar joint decreased and mean contact area increased significantly after CFL release. Significantly more inversion of the talus and calcaneus as well as calcaneal medial displacement was seen with weightbearing inversion after sectioning of the CFL. CONCLUSION: The CFL contributes considerably to lateral ankle instability. Higher grade sprains that include CFL injury result in significant decreases in rotation stiffness and peak torque, substantial alteration of contact mechanics at the ankle joint, increased inversion of the talus and calcaneus, and increased medial displacement of the calcaneus. CLINICAL RELEVANCE: Repair of an injured CFL should be considered during lateral ligament reconstruction, and there may be a role for early repair in high-grade injuries to avoid intermediate and long-term consequences of a loose or incompetent CFL.

Distal fibular malrotation and lateral ankle contact characteristics.

BACKGROUND: Any amount of malreduction of the syndesmotic joint compared with the uninjured syndesmosis has been associated with an adverse effect on functional outcome. The amount of malrotation that may lead to clinically relevant pressure change in this joint has not been reported. Our purpose was to determine whether small degrees of external and internal malrotation would be associated with statistically significant changes in contact pressure in the tibiofibular and talofibular articulations. METHODS: Twelve cadaveric ankles were osteotomized above the syndesmosis and instrumented with a rotatable distal fibula plate. Sensors at the distal tibiofibular and talofibular articulations recorded contact pressure and area at neutral position and at 5 and 10° of external and internal malrotation through a full range of ankle motion. RESULTS: Compared with neutral rotation, there was a significant decrease in contact pressure at the talofibular articulation with external rotation of 5° (103±113kPa versus 52±69kPa; P=0.01) and 10° (43±62kPa; P=0.01) in plantarflexion.Contact pressure at the tibiofibular articulation in plantarflexion increased with 10° of internal malrotation compared with neutral rotation (56±30kPa versus 74±38kPa; P=0.05) in plantarflexion. Contact area decreased significantly with plantarflexion and 10° of external rotation and increased significantly in plantarflexion and after cyclic loading with 10° of internal rotation (P≤0.05). CONCLUSION: Any degree of distal fibular external rotation significantly reduced contact pressure in the talofibular articulation with plantarflexion. A minimal increase in contact pressure was found in the tibiofibular and talofibular joints with plantarflexion and mild internal rotation of 5°, but pressure increased significantly in both articulations with 10° of internal rotation. The findings support clinical findings that subtle degrees of fibular malrotation may be associated with alteration of lateral ankle mechanics. LEVEL OF EVIDENCE: Controlled biomechanical study.

Avulsion fracture of the distal fibula is associated with recurrent sprain after ankle sprain in children.

PURPOSE: The purpose of this study was to clarify radiographic and clinical outcomes, as well as their association, of ankle sprain in children. METHODS: Patients who sustained a first-time ankle sprain were prospectively surveyed. Patients underwent radiography of the ankle in the mortise, lateral, anterior talofibular ligament (ATFL), and calcaneofibular ligament views at the first clinic visit to assess avulsion fractures of the distal fibula. Patients with avulsion fractures underwent radiography after 8 weeks to assess bone union. The treatment method was not standardized and was determined by the patient, their parents, and the treating physician. Recurrent sprain and quality of life were evaluated by using the Self-Administered Foot Evaluation Questionnaire and reviewing the medical records of patients. The association between avulsion fracture and recurrent sprain was assessed using univariate and multivariate analyses. RESULTS: A total of 143 patients with a median age of 9 (range 6-12) years were analyzed. Avulsion fractures were present in 89 (62%) patients. The sensitivity of the ATFL view for the diagnosis of avulsion fractures was 0.94, whereas that for the anteroposterior and lateral views was significantly lower at 0.46 (P < 0.001). Only 17% of fractures united at 8 weeks. Of 114 (follow-up rate, 80%) patients who were followed up for a median period of 24 months, recurrent sprain occurred in 41 (36%) patients. The incidence rate was significantly higher in patients with avulsion fractures than in patients without the fractures (44 vs. 23%, P = 0.027). In multivariate logistic regression analysis, avulsion fracture was independently associated with recurrent sprain (P = 0.027). CONCLUSION: More than one-third of patients experienced recurrent sprain. The presence of avulsion fracture was associated with an increased risk of recurrent sprain. Patients with avulsion fracture and their parents should be informed about the risk of recurrent sprain and subsequent ankle instability, and careful follow-up is needed for these patients. LEVEL OF EVIDENCE: III.

Assessment of Bony Subfibular Impingement in Flatfoot Patients Using Weight-Bearing CT Scans.

BACKGROUND:: Lateral hindfoot pain in patients with flatfoot deformity is frequently attributed to subfibular impingement. It remains unclear whether this is primarily due to bony or soft-tissue impingement. No studies have used weight-bearing CT scans to evaluate subfibular impingement. METHODS:: Patients with posterior tibial tendonitis were retrospectively searched and reviewed. Subjects had documented flatfoot deformity, posterior tibial tenderness, weight-bearing plain radiographs, and a weight-bearing CT scan. CT scans were evaluated for calcaneofibular impingement on the coronal view and talocalcaneal impingement on the sagittal view. The distance between these structures was measured, along with the sinus tarsi volume. In the second part of this study, 6 normal volunteers underwent weight-bearing CT scans on a platform that held both feet in 20 degrees of varus, followed by 20 degrees of valgus. The same measurements were performed. RESULTS:: Thirty-five percent of flatfoot patients with posterior tibial tendonitis had bony impingement between the fibula and calcaneus on the coronal view. Thirty-eight percent had bony impingement between the talus and calcaneus on the sagittal view. Subjects with bony impingement based on CT scan had significantly higher talonavicular abduction angles on plain radiographs than those without impingement. Sinus tarsi volume decreased by more than half when the subtalar joint moved from varus to valgus in normal controls. CONCLUSION:: Bony subfibular impingement in patients with flatfeet was less common than previously reported. Accurate diagnosis of bony impingement may be useful for surgical decision-making. LEVEL OF EVIDENCE:: Level III, retrospective comparative study.