The distance between the anterior and posterior edges of the fibula at a lateral internal rotation of 15° is associated with postoperative malreduction in patients with an ankle joint fracture combined with a lower tibiofibular syndesmosis injury

BACKGROUND

Malreduction remains a problem in patients with an ankle joint fracture combined with a lower tibiofibular syndesmosis injury. Current methods of malreduction evaluation have many limitations, and novel techniques are required.

OBJECTIVES

The aim of the study was to investigate the association between the distance between the anterior and posterior edges of the fibula at a 15° lateral internal rotation and postoperative malreduction in patients with an ankle joint fracture combined with a lower tibiofibular syndesmosis injury.

MATERIAL AND METHODS

This prospective observational cohort study enrolled 187 patients diagnosed with an ankle joint fracture combined with a lower tibiofibular syndesmosis injury between January 2020 and January 2022. The patients were divided into 2 groups according to their postoperative malreduction condition: the malreduction group and the non-malreduction group. After tibiofibular syndesmosis reduction, a computed tomography (CT) scan was used to measure the distance between the anterior and posterior edges of the fibula at a standard lateral position and a position with a lateral internal rotation of 15°. Demographic data and basic clinical characteristics were recorded for all patients.

RESULTS

The mean distance between the anterior and posterior edges of the fibula was longer in malreduction patients than non-malreduction patients at the standard lateral and 15° lateral internal rotation positions. At a lateral internal rotation of 15°, the distance between the anterior and posterior edges correlated negatively with the postoperative Mazur and American Orthopaedic Foot and Ankle Society (AOFAS) scores, and correlated positively with the length of hospitalization and fracture healing time. Receiver operating characteristic (ROC) curves revealed the potential postoperative malreduction diagnostic value of fibular anterior-posterior edge distance using an internal rotation of 15°. Postoperative AOFAS score, length of hospitalization, fracture healing time, and the distance between the anterior and posterior edges of the fibula at a lateral internal rotation of 15° were independent risk factors of malreduction.

CONCLUSIONS

The fibular anterior-posterior edge distance at an internal rotation of 15° is associated with postoperative ankle joint function and the occurrence of malreduction.

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.

Center-Center Surgical Technique With Dynamic Syndesmosis Fixation: A Cadaveric Pilot Study

The objective of this cadaveric biomechanical study was to evaluate if the center-center surgical technique is a reliable and repeatable method of achieving proper syndesmotic reduction when using dynamic syndesmotic fixation. Nine fresh frozen above-knee cadaveric lower extremities were used. Computerized tomography (CT) scans were first obtained for each intact specimen as the baseline for comparison. A simulated complete syndesmotic disruption was created by transection of all deltoid and syndesmotic ligaments. Instability of the ankle was confirmed with stress imaging using fluoroscopy. Each unstable specimen was repaired using the center-center surgical technique with dynamic syndesmosis fixation. A series of measurements from the axial CT images of intact and repaired specimens were used to determine the anatomic distal tibiofibular relationships for comparison of changes from intact to postfixation. All radiographic measurements were performed by 4 independent foot and ankle surgeons. The level of inter-rater reliability for all the measurements was found to be "moderate" to "excellent" agreement (ICC value: 0.865-0.983, 95% confidence interval: 0.634-0.996). There was no statistical difference found between rotational alignment of native and postfixation (a/b: p = .843; b-a: p = .125; θ: p = .062). There was a statistical difference detected for lateral alignment at the center of fibularis incisura between native and postfixation (average: -0.6 ± 0.8 mm, range: -2.3 to 1.2 mm, p < .001). There was no statistical difference found for the anteroposterior translation alignment between native and postfixation (d/e: p = .251; f: p = .377). This study demonstrated the use of the center-center surgical technique as a viable and repeatable method for achieving anatomical reduction of the tibiofibular syndesmosis when used with dynamic fixation modalities.

The Center-Center Image Closely Approximates Other Methods for Syndesmosis Reduction Clamp Placement

BACKGROUND

The optimal placement for a syndesmosis reduction clamp remains an open question. This study compared the center-center axis, which localizes clamp placement using only an internally rotated lateral ankle X-ray, with other common approaches, whose accuracy can only be confirmed using computed tomography (CT).

METHODS

Bone models of anatomically aligned (n = 6) and malreduced (n = 48) limbs were generated from CT scans of cadaveric specimens. Four axes for guiding clamp placement (center-center, centroid, B2, and trans-syndesmotic) were then analyzed, using digitally reconstructed radiographs derived from the bone models. Each axis' location was defined using angle-height pairs that describe axis orientation along the full anatomical region where syndesmosis fixation occurs.

RESULTS

In anatomically aligned limbs, the center-center axis was located on average (±95% CI [confidence interval]), 0.64° (±0.50°) internal rotation, 1.03° (±0.73°) internal rotation, and 2.09° (±7.29°) external rotation from the centroid, B2, and trans-syndesmotic axes, respectively. Fibular displacement altered the magnitude of limb rotation needed to identify the center-center axis.

CONCLUSION

The center-center technique is a valid method that closely approximates previously described methods for syndesmosis clamp placement without using CT, and the magnitude of C-arm rotation needed to transition from a talar dome lateral to a center-center view may be a potential method for assessing syndesmosis reduction.

LEVELS OF EVIDENCE

Level III: Retrospective comparative study.

Post-Operative Greater Tuberosity Resorption or Malreduction Is Associated with Poor Prognostic Outcomes in Patients with Proximal Humeral Fractures Treated Operatively-A Single-Center Retrospective Cohort Study

(1) Background: Proximal humerus fractures can be a debilitating condition if not properly treated. These fracture patterns are varied and differ in every patient. Functional outcomes may be determined by the integrity of the shoulder girdle involving the rotator cuff insertion. The post-operative resorption or malreduction of the greater tuberosity (GT) is an important factor contributing to the poor functional outcome of a patient. Thus, we intend to evaluate the cause-and-effect relationship between GT complications and clinical prognosis and outcomes. (2) Methods: A single-center retrospective comparative study was performed to evaluate the functional outcomes of patients undergoing operative fixation for this injury. A total of 387 consecutive cases treated operatively from 2019-2021 were included for analysis. (3) Results: 94 cases fulfilled our criteria for analysis. A matched-group comparison of 19 patients each was performed to compare demographics, post-operative fracture characteristics and clinical outcomes. (4) Conclusions: The resorption or malreduction of the GT contributes greatly to the prognostic outcome in patients treated with open reduction and internal fixation (ORIF) surgery. In our demographic study, obesity is another contributing factor affecting the parameters of post-operative reduction in proximal humerus fractures. Appropriate surgical planning and post-operative multidisciplinary care must be taken into consideration to attain a satisfactory prognostic outcome.

Reduction of Posterior Malleolus Fractures With Open Fixation Compared to Percutaneous Treatment

Background

Operative decision making between approaches to posterior malleolus reduction remains a challenge. The purpose of this study is to compare the quality of reduction between percutaneous and open reduction of posterior malleolus fractures and to identify factors associated with malreduction.

Methods

Operatively managed ankle fractures that included posterior malleolus fixation were reviewed. Fracture characteristics were determined on preoperative CT scans. Initial postoperative radiographs were used to measure reduction of the posterior malleolus articular surface and graded as satisfactory (<2 mm step-off) or malreduced (≥2 mm step-off). Final postoperative PROMIS scores and 1-year complications were compared between percutaneous and open cohorts. A multivariate stepwise regression model was used to evaluate predictors for malreduction.

Results

A total of 120 patients were included. Open reduction was performed in 91 (75.8%) compared with 29 (24.2%) who underwent percutaneous reduction. Malreduction (≥2-mm articular step-off) occurred in 11.7% of patients. Malreduction rates were significantly higher with percutaneous fixation than open fixation (24.1% vs 7.7%, P = .02). Multiple fragments and those with ≥5 mm of displacement demonstrated higher malreduction rates with percutaneous fixation (P < .05 for both), whereas single fragments and those with <5 mm of displacement experienced similar malreduction rates with percutaneous or open fixation. Initial displacement ≥5 mm (relative risk [RR] = 3.8, 95% CI = 1.2-11.5, P = .02) and percutaneous treatment (RR = 4.1, 95% CI = 1.6-10.5, P < .01) were identified as independent risk factors for malreduction. There were no significant differences in 1-year complication rates or final PROMIS scores between groups.

Conclusion

Open reduction of the posterior malleolus may lead to improved fracture reduction compared to percutaneous reduction without significant increase in complications. Open fixation improves reduction among fractures with multiple fragments or ≥5 mm of displacement, whereas fractures with a single fragment or <5 mm of displacement achieve similar reductions regardless of approach. Initial displacement ≥5 mm and percutaneous reduction are independent risk factors for malreduction.

Level of evidence

Level III, therapeutic.

Prospective Results of the Modified Glide Path Technique for Improved Syndesmotic Reduction During Ankle Fracture Fixation

BACKGROUND

Malreduction after syndesmotic stabilization occurs in as many as 52% of cases and has been shown to detrimentally affect clinical outcomes. We propose that the modified Glide Path technique reduces the occurrence of syndesmotic malreduction.

METHODS

This study is a prospective series comparing 16 patients reduced with the modified Glide Path technique with a retrospectively reviewed series of 25 patients reduced with a traditional technique using fluoroscopy and a clamp. The modified Glide Path technique consists of manual reduction of the fibula and placement of a Kirschner wire through the fibula and tibia along the transmalleolar axis. The syndesmosis can then be reduced along the glide path created by the Kirschner wire to prevent posterior or anterior malreduction. Computed tomographic scans of the repaired and contralateral ankles were obtained postoperatively to assess reduction.

RESULTS

We found a statistically significant decrease of syndesmotic malreductions using the modified Glide Path technique when compared with technique that did not use a glide path. In our study, 2 of 16 patients (12.5%) had syndesmotic malreductions using the modified Glide Path technique, compared with 11 of 25 patients (44%) with syndesmotic malreductions in the historical cohort.

CONCLUSION

The modified Glide Path technique is a simple method for ankle syndesmotic reduction. The technique has lower rates of malreduction compared with historical methods and may be useful for most operative syndesmotic injuries.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Does Proximal Placement of the Syndesmotic Reduction Clamp Affect the Optimal Position for the Medial Tine? A Cadaveric Pilot Study

Sagittal plane syndesmotic malreduction is associated with off-axis, eccentric reduction clamping and preferential placement of the medial tine anteriorly has been proposed to minimize the malreduction risk. Although clamp placement 1cm proximal to the plafond is recommend, no previous study has assessed whether differences in the anatomic position of the fibula within the incisura (eccentric 1cm superior and concentric 2 cm superior to the tibial plafond) affect the optimal position for the clamps medial tine during reduction of the syndesmosis. The purpose of the present cadaveric pilot study was to evaluate and compare the sagittal syndesmotic malreduction rate with various clamping vectors, 1cm and 2cm from the tibial plafond, respectively. Six through the knee cadaveric specimens were obtained. Kirschner wires and a surgical maker were used to denote placement of the reduction clamp laterally on the peroneal ridge of the fibula, and medially within the anterior, middle, and posterior thirds (Zones A, B, C) of tibia's width; 1 cm and 2 cm from the plafond. CT scans were obtained as controls, followed by destabilization of the syndesmosis. Reductions were then performed sequentially at each level (1 cm, 2 cm) and zone (A, B, C); and CT scans repeated for assessment. In most specimens (n = 5), an eccentric (1 cm) to concentric (2 cm) positional transition was observed within incisura fibularis. The transition altered the resulting fibular displacements in some specimens (2A anterior, vs 2B posterior), resulting in a higher malreduction rate with anterior (zone 2A, 33%) vs central (Zone 2B, 17%) positioning of medial tine. Although no definitive conclusions can be reached from the present pilot study, future studies with a greater number of specimens and clamping vectors are warranted to determine whether positional transitions of the fibula within the incisura fibularis affect the optimal position for the clamps medial tine.

Dual-construct fixation is recommended in ipsilateral femoral neck fractures with infra-isthmus shaft fracture: A STROBE compliant study

ABSTRACT

The aim of this study was to evaluate the risk factors related to osteosynthesis failure in patients with concomitant ipsilateral femoral neck and shaft fractures, including old age; smoking habit; comminuted fragments; infra-isthmus fracture; angular malreduction; unsatisfactory reduction (fracture gap >5 mm); and treatment with single construct.Patients over the age of 20 with concomitant ipsilateral femoral neck and shaft fractures diagnosed at a level one medical center between 2003 and 2019 were included. Treatment modalities included single construct with/without an antirotational screw for the neck and dual constructs. Radiographic outcomes were assessed from anteroposterior and lateral hip radiographs at follow-up. Fisher exact test was used to analyze categorical variables. The presence of avascular necrosis of the femoral head, delayed union, atrophic or hypertrophic nonunion of the femoral shaft fracture, and loss of reduction were identified as factors related to treatment failure.A total of 22 patients were included in this study. The average age was 58.5 years, and the majority was male (68.2%). The minimum radiographic follow-up duration was 12 months, and the median follow-up time was 12 (interquartile range 12-24) months.Femoral neck osteosynthesis failed in 3 patients, whereas femoral shaft osteosynthesis failed in 12 patients. Fisher exact test demonstrated the failure of femoral shaft osteosynthesis was significantly more frequent in the single-construct cohort in 16 infra-isthmus femoral fracture cases (P = .034).In ipsilateral femoral neck and infra-isthmus shaft fractures, it is better to treat the neck and shaft fractures with separate implants (dual constructs).In a dual-construct cohort, separate plate fixation of the femoral shaft achieved a better result in terms of bone union than retrograde nailing of the shaft (bone union rate: 4/8 vs 0/2).

Reliability of the "Clinical Tibiofibular Line" Technique for Open Syndesmosis Reduction Assessment

BACKGROUND

When intraoperative computed tomography (CT) is unavailable, open syndesmosis assessment is a universally available, safe alternative that is more accurate than radiographic assessment. However, it has a documented malreduction rate of up to 16%. This may be improved upon with a validated technique for assessing the accuracy of open syndesmosis reductions. The "tibiofibular line" (TFL) is a CT-based technique found to be sensitive for malreduction. The purpose of this study was to assess the feasibility of adapting the CT-TFL method into a reliable intraoperative open technique by refining the methodology of previous work exploring the clinical TFL technique.

METHODS

Three observers were instructed to clinically simulate the TFL on cadaveric lower limbs. For each specimen, observers repeated and recorded 3 clinical TFL measurements for each of 4 measurement series representing different degrees of fibula reduction. Intraclass correlation was used to assess intra- and interobserver reliabilities.

RESULTS

Mean intraobserver reliability was .88. Mean interobserver reliability was .75. Both intra- and interobserver reliabilities were highest for anatomic syndesmosis reduction.

CONCLUSION

The findings of excellent to near perfect intraobserver and good to excellent interobserver reliability indicate the feasibility of translating the CT-TFL into a reliable open technique.

LEVELS OF EVIDENCE

Level III: Diagnostic study.

Predictors of Malreduction in Zone II and III Fifth Metatarsal Fractures Fixed With an Intramedullary Screw

BACKGROUND

Proper implant selection and placement is crucial during fixation of zone II and III fifth metatarsal fractures to avoid postoperative complications. This study examined the effects of screw parameters and placement on malreduction, delayed union, nonunion, and refracture rate.

METHODS

A retrospective review of zone II and proximal zone III fifth metatarsal fractures managed with intramedullary screw fixation was conducted. Comparisons were made between cortex distraction (gap) and ratios of screw length, diameter, and entry point. Further analysis was carried out between time to union and distraction in the lateral and plantar cortices.

RESULTS

The plantar and lateral gaps were both associated with the mean entry point ratio on the lateral and anteroposterior (AP) views (P < .001 for both views). No association between the plantar and lateral gaps and the screw diameter ratio (P = .393 for AP and P = .981 for lateral) or the screw length ratio (P = .966 for AP and P = .740 for lateral) was identified. The ratio of postoperative to preoperative apex height on AP and lateral views was correlated with the presence of lateral and plantar fracture gaps (P < .001). The presence of a plantar gap was associated with increased time to union (P = .022). A majority of fractures showed radiographic union at 12 weeks (38/43). Only 5 of 38 patients had delayed union. There were no refractures or nonunions as per available records.

CONCLUSION

Plantar or lateral fracture site distraction (gap) was not influenced by screw diameter ratio or screw length ratio. The entry point ratio had a significant effect on plantar and lateral gaps on postoperative radiographs, with lateral and inferior placement leading to fracture site distraction. Patients with a plantar gap did have an increased risk of delayed union. The results of this study emphasize the significance of the entry point when managing zone II and III fifth metatarsal base fractures.

LEVEL OF EVIDENCE

Level IV, case series.

Getting the Starting Point Right: Prevention of Skiving and Fibular Cortical Breach During Suture Button Placement for Syndesmotic Ankle Injuries

The use of suture button (SB) devices in the treatment of syndesmotic ankle injuries is increasing. These constructs have demonstrated better syndesmotic reduction, improved clinical outcomes, and lower rates of hardware removal compared with screw fixation. However, placing a SB device without a fibular plate can be technically challenging. In this technique tip, we use an illustrative case to demonstrate a technique tip that minimizes the risk of anterior or posterior cortical breach of the fibula and helps facilitate more accurate placement of a SB device.Levels of Evidence: Level V: Expert opinion.

Functional Outcomes Following Operative and Nonoperative Management of Weber C Ankle Fractures: A Systematic Review

Weber C ankle fractures are unstable ankle fractures occurring above the syndesmosis. These fractures are often managed operatively, although a small population of patients are still selected for nonoperative management. This study primarily aimed to summarize the current evidence on functional outcomes for Weber C patients managed operatively and nonoperatively. Evidence on secondary outcomes such as complications and radiographic outcomes were also reviewed. This systematic search was conducted according to PRISMA guidelines. A literature search was conducted using the EMBASE, Medline, and Central databases. A total of 26 studies were included in the final analysis. All papers studied the management of Weber C fractures using open reduction and internal fixation (ORIF). Three main functional outcome scores were identified: American Orthopedic Foot and Ankle Society score, Olerud-Molander Ankle Score, and Foot and Ankle Outcome Score. Only 1 study compared operative and conservative management, which showed similar outcomes for either option (median Olerud-Molander Ankle Score 95 [range 20 to 95] vs 100 [70 to 100], respectively). Complications associated with operative management included infection, wound dehiscence, implant failure, and malunion or nonunion. The mean rate of syndesmosis malreduction was 18.2%. This study showed that operative management, regardless of the method of ORIF used, as well as nonoperative management resulted in good functional outcomes, indicating that patient selection for either method is important. However, there is limited evidence on the complications and radiographic outcomes associated with nonoperative management. We recommend further studies to compare all ORIF methods with conservative management and examine the complications associated with nonoperative management.

Three-Dimensional Computed Tomographic Characterization of Normal Anatomic Morphology and Variations of the Distal Tibiofibular Syndesmosis

Malreduction of distal tibiofibular syndesmosis (DTFS) leads to poor functional outcomes after ankle fracture surgery. Difficulty achieving anatomic alignment of the syndesmosis is due to variable morphology of the fibular incisura of the tibia and a paucity of literature regarding its morphologic characteristics. We surveyed 775 consecutive ankle computed tomography (CT) scans performed from June 2008 to December 2011, and 203 (26.2%) were included for evaluation. Two observers performed quantitative measurements and qualitative evaluated fibular incisura morphology. Tang ratios for fibular rotation, anterior and posterior tibiofibular distances, fibular incisura depth, and subjective morphologies on CT were assessed using conventional multiplanar reconstruction (MPR) and maximum intensity projections (MIPs). On conventional CT, the mean Tang ratio was 0.97 ± 0.06; the mean anterior tibiofibular distance was 2.17 ± 0.87 mm; the mean posterior tibiofibular distance was 3.52 ± 0.94 mm; and the mean depth of fibular incisura was 3.29 ± 1.19 mm. Five morphologic variations of the fibular incisura were identified: crescentic, trapezoid, flat, chevron, and widow's peak. The most common fibular incisura morphology was crescentic (61.3%), followed by trapezoid shape (25.1%); the least common morphology was flat (3.1%). Interobserver variability with intraclass correlation coefficient (ICC) was slightly higher for all quantitative measures on MPR (ICC = 0.72 to .81) versus MIP (ICC = 0.64 to 0.75). ICC for incisura shape and depth assessments was poor on both modalities (0.13 to 0.38). This comprehensive CT study reports on quantitative and qualitative descriptive measures to evaluate fibular incisura morphologies and fibular orientation. It also defines the frequency of DTFS measures and the interobserver performance on 2 CT evaluation methods.

Is It Possible to Overcompress the Syndesmosis?

The case we present suggests that it might be possible to overcompress the syndesmosis, causing subluxation of the talus within the ankle mortise. A 26-year-old female patient had had a Weber Type C ankle fracture internally fixed with a lateral plate and syndesmosis screws. Despite the fibula appearing well reduced and computed tomography imaging showing a well-aligned fibula within the fibular notch, anteromedial subluxation of the talus was present in the ankle mortise. Examination with the patient under anesthesia revealed a stable syndesmosis fixation; however, talar malpositioning was not affected by the foot position. The syndesmosis fixation was revised sequentially. As the fixation was relaxed sequentially, the talus appeared to reduce within the ankle mortise, with restoration of the previously obliterated medial clear space. The syndesmosis was stabilized with a single 3.5-mm cortical screw in a reduced position. The patient had made a full recovery at the 12-month follow-up examination, having undergone elective syndesmosis screw removal at 12 weeks postoperatively. Several studies have suggested that it might not be possible to overcompress the syndesmosis and have even advocated the use of a lag screw technique for syndesmosis fixation. Based on the present case, we would advise a degree of caution with this approach, because it might be possible to overcompress the syndesmosis and cause significant subluxation of the tibiotalar articulation.

Effects of Volar Tilt, Wrist Extension, and Plate Position on Contact Between Flexor Pollicis Longus Tendon and Volar Plate

PURPOSE

Volar plates positioned at, or distal to, the watershed line have been shown to have a higher incidence of attritional rupture of the flexor pollicis longus (FPL). In this study, we aimed to evaluate the effect of wrist extension and volar tilt on the contact between the plate and the FPL tendon in a cadaver model. We hypothesized that, following volar plate application, loss of native volar tilt increases the contact between the FPL and the plate at lower degrees of wrist extension.

METHODS

A volar locking plate was applied on 6 fresh-frozen cadavers. To determine the contact between the plate and the FPL tendon, both structures were wrapped with copper wire and circuit conductivity was monitored throughout wrist motion. A lateral wrist radiograph was obtained at each circuit closure, indicating tendon-plate contact. Baseline measurements were obtained with plate positioned at Soong grades 0, 1, and 2. An extra-articular osteotomy was made and contact was recorded at various volar tilt angles (+5°, 0°, -5°, -10°, -15°, and -20°) in 3 different plate positions. A blinded observer measured the degree of wrist extension on all lateral radiographs. Data were analyzed using linear mixed-effects regression model.

RESULTS

Plates placed distal to the watershed line had the most contact throughout wrist range of motion. Significantly, less wrist extension was required for contact in wrists with neutral or dorsal tilt and in distally placed volar plates. Volar tilt, wrist extension, and plate position were 3 independent risk factors determining contact between plate and tendon.

CONCLUSIONS

Loss of volar tilt, increased wrist extension, and higher Soong grade plate position result in greater contact between wire-wrapped FPL tendon and plate.

CLINICAL RELEVANCE

The FPL/plate contact chart generated in this study may be used to assess the risk of rupture in the clinical setting.

Medial Clamp Tine Positioning Affects Ankle Syndesmosis Malreduction

OBJECTIVES

To determine whether the position of the medial clamp tine during syndesmotic reduction affected reduction accuracy.

DESIGN

Prospective cohort.

SETTING

Urban Level 1 trauma center.

PATIENTS

Seventy-two patients with operatively treated syndesmotic injuries.

INTERVENTION

Patients underwent operative fixation of their ankle syndesmotic injuries using reduction forceps. The position of the medial clamp tine was then recorded with intraoperative fluoroscopy. Malreduction rates were then assessed with bilateral ankle computerized tomography.

MAIN OUTCOME MEASUREMENT

Fibular position within the incisura was measured with respect to the uninjured side to determine whether a malreduction had occurred. Malreductions were then analyzed for associations with injury pattern, patient demographics, and the location of the medial clamp tine.

RESULTS

A statistically significant association was found between medial clamp position and sagittal plane syndesmosis malreduction. In reference to anterior fibular translation, there was a 0% malreduction rate in the 18 patients where the clamp tine was placed in the anterior third, a 19.4% malreduction rate in the middle third, and 60% malreduction rate in the posterior third (P = 0.006). In reference to posterior fibular translation, there was a 11.1% malreduction when clamp placement was in the anterior third, a 16.1% malreduction rate in the middle third, and 60% malreduction rate in the posterior third (P = 0.062). There were no significant associations between medial clamp position and coronal plane malreductions (overcompression or undercompression) (P = 1).

CONCLUSIONS

When using reduction forceps for syndesmotic reduction, the position of the medial clamp tine can be highly variable. The angle created with off-axis syndesmotic clamping is likely a major culprit in iatrogenic malreduction. Sagittal plane malreduction appears to be highly sensitive to clamp obliquity, which is directly related to the medial clamp tine placement. Based on these data, we recommend placing the medial clamp tine in the anterior third of the tibial line on the lateral view to minimize malreduction risk.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Incisura Morphology as a Risk Factor for Syndesmotic Malreduction

BACKGROUND

The goal of this study was to objectively assess if rotational or translational syndesmotic malreduction is associated with certain syndesmotic morphologies. Prior studies based on subjective assessment of syndesmotic morphology and reduction have not shown any difference between groups.

METHODS

Thirty-five prospectively recruited patients with operatively treated syndesmotic injuries were recruited at an Urban Level I Trauma Center. Patients underwent postoperative bilateral computed tomographic (CT) scans of the ankle to assess incisura depth and syndesmotic reduction. The uninjured extremity was used as a control. Side-to-side differences of syndesmotic reduction were measured at several anatomic points and compared to the incisura depth.

RESULTS

There was a significant correlation between more shallow syndesmoses and increased anterior translation of the fibula in the incisura (r = -0.63, P ≤ .001). Six of 8 patients with "shallow" (≤2.5 mm) incisura were anteriorly malreduced greater than or equal to 1.5 mm compared to the contralateral ankle. The anterior malreduction rate in those with a shallow incisura was significantly greater than in the "non-shallow" patients (P < .001). There were 9 patients with incisurae greater than or equal to 4.5 mm deep. Five of the "deep" patients had posterior malreductions greater than or equal to 1.5 mm. The posterior malreduction rate in the "deep" group was significantly greater than the "non-deep" patients (P = .02). There was a significant correlation between increasing syndesmotic depth and increased malrotation (r = .46, P = .01).

CONCLUSION

Syndesmotic morphology was found to be associated with specific malreduction patterns. Shallow syndesmoses were correlated with anterior fibular malreduction, and were less likely to be malrotated. Conversely, deep syndesmoses predisposed to posterior sagittal plane and rotational malalignment. Preoperative CT scans that assess the syndesmosis morphology may allow surgeons to alter reduction strategies to avoid syndesmotic malreduction.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Increased Reduction Clamp Force Associated With Syndesmotic Overcompression

BACKGROUND

The distal tibiofibular syndesmosis is disrupted in up to 45% of operatively treated ankle fractures, and syndesmotic malreduction has historically been correlated with poor outcome. The purpose of this study was to quantify the clamp force used during syndesmotic reduction and to evaluate the effect of clamp force on fibular overmedialization (overcompression) at the level of the distal tibiofibular syndesmosis.

METHODS

A prospectively recruited cohort of 21 patients underwent operative syndesmotic reduction and fixation. A ball point periarticular reduction forceps that was modified to include a load cell in one tine was used for the reduction, and the clamp force required for reduction was measured. Patients underwent postoperative bilateral computed tomographic scans of the ankle and hindfoot to assess syndesmotic reduction. The uninjured extremity was used as a control. Side-to-side differences in fibular medialization, translation, and rotation within the tibial incisura were measured. These findings were correlated with the reduction clamp force utilized to obtain the reduction.

RESULTS

Syndesmotic overcompression (fibular medialization greater than 1.0 mm when compared with noninjured ankle) was seen in 11 of 21 patients (52%). Increased clamp force significantly correlated with syndesmotic overcompression. The mean reduction clamp forces were 88 N for the undercompressed group, 130 N for the adequately compressed group, and 163 N for the overcompressed group.

CONCLUSION

This study demonstrated a significant correlation between increased clamp forces and syndesmotic overcompression, and determined objective forces that lead to overcompression. Our results indicate that surgeons should be cognizant of the clamp force used for syndesmotic reduction.

LEVEL OF EVIDENCE

Level III, case-control series, in accordance with STROBE guidelines.

Use of a Hybrid Operating Room to Improve Reduction of Syndesmotic Injuries in Ankle Fractures: A Case Report

Ankle fractures are one of the most common orthopedic injuries requiring operative treatment, and approximately 1 in 4 ankle fractures will have an associated distal tibiofibular syndesmosis disruption. Syndesmotic reduction is crucial to restoring ankle function and preventing the development of arthritis. The hybrid operating room provides 3-dimensional intraoperative imaging capabilities that can enable the surgeon to ensure the syndesmosis is appropriately reduced, particularly by comparing it with the contralateral ankle. By confirming the syndesmosis reduction intraoperatively, the risk of a return to the operating room for revision surgery is decreased.

Technical Considerations in the Treatment of Syndesmotic Injuries Associated With Ankle Fractures

Malleolar ankle fractures associated with syndesmotic injuries are common. Diagnosis of the syndesmotic injury can be difficult and often requires intraoperative fluoroscopic stress testing. Accurate reduction and stable fixation of the syndesmosis are critical to maximize patient outcomes. Recent literature has demonstrated that the unstable syndesmosis is particularly prone to iatrogenic malreduction. Multiple types of malreduction can occur, including translational, rotational, and overcompression. Knowledge of the technical details regarding intraoperative reduction methods and reduction assessment can minimize the risk of syndesmotic malreduction and improve patient outcomes.