Postoperative Outcomes Between Positive and Negative Electrodiagnosis in Patients With Tarsal Tunnel Syndrome: A Retrospective Comparative Study.

BACKGROUND: The sensitivity of diagnosing tarsal tunnel syndrome with an electrodiagnostic study is just over 50%. Given this low reliability, many surgeons prefer to make a diagnosis solely from a physical examination, despite reported electrodiagnostic findings. Thus, to understand the clinical ramifications between these 2 methods of diagnosis, this investigation compared the postoperative outcomes following a tarsal tunnel release between patients with positive and negative preoperative electrodiagnosis (EDx). METHODS: This study retrospectively reviewed 53 consecutive patients who underwent tarsal tunnel release by a single surgeon between 2015 and 2022. The primary outcome was pain level using visual analog scale (VAS) whereas the secondary outcomes were 36-Item Short Form Health Survey questionnaire, Foot and Ankle Ability Measure, recovery times (time to return to activities of daily living, work, and sports), and complications. Pre- and postoperative functional outcomes were compared within each EDx group using a paired sample t test. Postoperative outcomes between groups were compared using a generalized linear model adjusted for potential confounders. RESULTS: Both EDx groups (positive studies = 31 patients and negative studies = 22 patients) demonstrated significant improvement of all functional outcomes (P < .001). We found no significant difference in recovery time or postoperative outcomes between the 2 groups (P > .05). Multivariable analysis showed diabetes (risk ratio [RR] = 1.79, 95% CI 1.11-2.90) and longer duration of symptoms before surgery (RR = 1.02, 95% CI 1.00-1.04) as prognostic factors for residual pain following tarsal tunnel release. CONCLUSION: In our series, we found that preoperative electrodiagnostic results did not prognosticate postoperative functional outcomes or recovery times after tarsal tunnel release.

Bilateral Os Trigonum Fracture Treated With Simultaneous Posterior Ankle Arthroscopy.

This is a case report of a 21-year-old female undergraduate student who sustained bilateral ankle injuries while jumping from a moving van wearing 3-inch high heel shoes. Upon initial presentation, her injury was treated conservatively as an acute bilateral ankle sprain for 6 weeks. However, the patient reported no improvement of pain and remained unable to self-ambulate. Bilateral MRI and CT scans of both ankles demonstrated bilateral os trigonum fractures. She underwent bilateral posterior ankle arthroscopic débridement of both os trigonum. At the postoperative 36-month follow-up, the patient reported notable improvement of all functional outcomes (36-item Short Form survey and Foot and Ankle Ability Measure), reported return to the same level of sports activities, and experienced no pain (visual analog scale) on either ankle. This is the first report in the literature of bilateral os trigonum fracture treated with simultaneous posterior ankle arthroscopic débridement.

Interaction of loading and ligament injuries in subtalar joint instability quantified by 3D weightbearing computed tomography.

Despite decades of research since its first description, subtalar joint instability remains a diagnostic enigma within the concept of hindfoot instability. This could be attributed to current imaging techniques, which are impeded by two-dimensional measurements. Therefore, we used weightbearing computed tomography imaging to quantify three-dimensional displacement associated with subtalar joint instability. Three-dimensional models were generated in seven paired cadaver specimens to compute talocalcaneal displacement after different patterns of axial load (85 kg) combined with torque in internal and external rotation (10 Nm). Sequential imaging was repeated in the subtalar joint containing intact ligaments to determine reference displacement. Afterward, the interosseus talocalcaneal ligament (ITCL) or calcaneofibular ligament (CFL) was sectioned, then the ITCL with CFL and after the ITCL, CFL with the deltoid ligament (DL). The highest translation could be detected in the dorsal direction and the highest rotation occurred in the internal direction when external torque was applied to the foot without load. These displacements differed significantly from the condition containing intact ligaments, with a mean difference of 1.6 mm (95% CI, 1.3 to 1.9) for dorsal translation and a mean of 12.4° (95% CI, 10.1 to 14.8) for internal rotation. Clinical relevance: Our study provides a novel and noninvasive analysis to quantify subtalar joint instability based on three-dimensional WBCT imaging. This approach overcomes former studies using trans-osseous fixation to determine three-dimensional subtalar joint displacement and implements an imaging device and software modalities that are readily available. Based on our findings, we recommend applying torque in external rotation to the foot to optimize the detection of subtalar joint instability.

Micro-CT analysis of the Lisfranc complex reveals higher bone mineral density in dorsal compared to plantar regions.

Injuries to the Lisfranc complex may require surgical fixation, the stability of which may be correlated with bone mineral density (BMD). However, there is limited research on regional BMD variations in the Lisfranc complex. This study used quantitative micro-CT to characterize regional BMD in the four bones (medial cuneiform, intermediate cuneiform, first metatarsal, and second metatarsal) of this complex. Twenty-four cadaveric specimens were imaged with a calibration phantom using micro-CT. Each bone was segmented and divided into eight regions based on an anatomical coordinate system. BMD for each octant was calculated using scan-specific calibration equations and average image intensity. Differences between regions were analyzed using ANOVA with post hoc analysis and differences between groups of four octants in each plane were analyzed with t-tests with significance level α = 0.05. The highest density region in the medial cuneiform was the distal-dorsal-lateral and dorsal regions showed significantly higher BMD than plantar regions. The intermediate cuneiform had the highest density in the distal-dorsal-medial region and the dorsal and medial regions had higher BMD than the plantar and lateral regions, respectively. The densest region of the first metatarsal was the distal-dorsal-lateral and distal regions had significantly higher BMD than proximal regions. In the second metatarsal, the distal-dorsal-medial region had the highest density, and the distal, dorsal, and medial regions had significantly higher BMD than the proximal, plantar, and lateral regions, respectively. The predominant finding was a pattern of increased density in the dorsal bone regions, which may be relevant in the surgical management of Lisfranc injuries.

Talar Dome Access Through Posteromedial Surgical Intervals for Fracture Care.

BACKGROUND: Posterior talar body fractures are rare injuries without a consensus surgical approach. This study evaluates the accessible area of the talar dome through 2 posteromedial approach intervals (posteromedial [PM] and modified posteromedial [mPM]) both with and without distraction. METHODS: Ten male cadaveric legs (5 matched pairs) were included. A PM approach, between flexor hallucis longus (FHL) and the tibial neurovascular bundle, and an mPM approach, between FHL and Achilles tendon, was performed on each pair. In total, 4 mm of distraction across the tibiotalar joint was applied with the foot held in neutral position. Accessible dome surface area (DSA) was outlined by drilling with a 1.6-mm Kirschner wire with and without distraction. Specimens were explanted and analyzed by micro-computed tomography with 3-dimensional reconstruction. Primary outcomes were total accessible DSA and sagittal plane access at predetermined intervals. RESULTS: The PM approach allowed access to 19.1% of the talar DSA without distraction and 33.1% of the talar dome with distraction (P < .001). The mPM approach provided access to 20.4% and 35.6% of the talar DSA without and with distraction (P < .001). Both approaches demonstrated similar sagittal plane access at all intervals except the lateral border of the talus, where the mPM approach provided greater access both without distraction (20.5% vs 4.38%, P = .002) and with distraction (34.3% vs 17.8%, P = .02). CONCLUSION: The mPM approach, using an interval between FHL and Achilles tendon, provides similar access to the posterior surface of talar dome and better sagittal plane access to the most lateral portion of the dome. The mPM interval provides the advantage of avoiding direct dissection of the tibial nerve or posterior tibial artery. Using an external fixator for distraction can improve talar dome visualization substantially. LEVEL OF EVIDENCE: Level V, Cadaveric Study.

Outcomes and Complications of Open vs Posterior Arthroscopic Subtalar Arthrodesis: A Prospective Randomized Controlled Multicenter Study.

BACKGROUND: Open subtalar arthrodesis is the standard treatment for subtalar arthritis. Posterior arthroscopic subtalar arthrodesis (PASTA) has recently gained increasing popularity due to a shorter recovery time and better cosmesis. However, studies comparing outcomes and complications between these 2 techniques are limited. METHODS: In total, 56 patients with subtalar joint arthritis were prospectively randomized to 2 parallel groups to receive either PASTA (n = 28 patients) or open subtalar arthrodesis (n = 28 patients). The minimum follow-up period was 12 months. Primary outcome was union rate confirmed on postoperative computed tomography (CT) scan. Secondary outcomes were union time; visual analog scale (VAS), Short Form-36 (SF-36), and Foot and Ankle Ability Measure (FAAM) scores; tourniquet time; and complications. RESULTS: Union time (9.4 vs 12.8 weeks) and recovery time (time to return to activities of daily living [8.4 vs 10.8 weeks], work [10.6 vs 12.9 weeks], and sports [24.9 vs 32.7 weeks]) were significantly shorter with PASTA than with the open technique (P < .05 all). Both techniques led to significant improvements in all functional outcomes (FAAM, SF-36, and VAS scores; P < .01 all); however, there was no significant difference between the techniques in these outcomes (P > .05 all). Other outcomes, including tourniquet time (55.8 vs 67.2 min), union rate (96.3% vs 100%), and complication rate, were not significantly different between the techniques. CONCLUSION: Both open and PASTA techniques led to significant improvements in pain and function in patients with isolated subtalar joint arthritis. Although short-term functional outcomes and complication rates were not significantly different between the techniques, the PASTA technique was better at shortening the union and recovery times. LEVEL OF EVIDENCE: Level I, prospective multicenter randomized controlled trial.

Assessment of Hindfoot Alignment Comparing Weightbearing Radiography to Weightbearing Computed Tomography.

BACKGROUND: Hindfoot alignment view (HAV) radiographs are widely utilized for 2-dimensional (2D) radiographic assessment of hindfoot alignment; however, the development of weightbearing computed tomography (WBCT) may provide more accurate methods of quantifying 3-dimensional (3D) hindfoot alignment. The aim of this study was to compare the 2D calcaneal moment arm measurements on HAV radiographs with WBCT. METHODS: This retrospective cohort study included 375 consecutive patients with both HAV radiographs and WBCT imaging. Measurement of the 2D hindfoot alignment moment arm was compared between both imaging modalities. The potential confounding influence of valgus/varus/neutral alignment, presence of hardware, and motion artifact were further analyzed. RESULTS: The intraclass correlation coefficients (ICCs) of interobserver and intraobserver reliability for measurements with both imaging modalities were excellent. Both modalities were highly correlated (Spearman coefficient, 0.930; P < .001). HAV radiographs exhibited a mean calcaneal moment arm difference of 3.9 mm in the varus direction compared with WBCT (95% CI, -4.9 to 12.8). The difference of hindfoot alignment between both modalities was comparable in subgroups with neutral/valgus/varus alignment, presence of hardware, and motion artifact. CONCLUSION: Both HAV radiographs and WBCT are highly reliable and highly correlated imaging methods for assessing hindfoot alignment. Measurements were not influenced by severe malalignment, the presence of hardware, or motion artifact on WBCT. On average, HAV radiographs overestimated 3.9 mm of varus alignment as compared with WBCT. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Imaging of Peritalar Instability.

Undiagnosed medial ankle instability can be a prerequisite for pathogenic progression in the foot, particularly for adult acquired flatfoot deformity. With the complex anatomy in this region, and the limitations of each individual investigational method, accurately identifying peritalar instability remains a serious challenge to clinicians. Performing a thorough clinical examination aided by evaluation with advanced imaging can improve the threshold of detection for this condition and allow early proper treatment to prevent further manifestations of the instability.

Mapping of Posterior Talar Dome Access Through Posteromedial Versus Posterolateral Approaches.

OBJECTIVE: To evaluate the accessible area of the talar dome through 2 standard posterior approaches [posteromedial (PM) and posterolateral (PL)] with and without distraction. METHODS: A standard PM or PL approach was performed with and without external fixator distraction on 12 through-knee cadaveric legs (6 matched pairs). The accessible area of the talar dome was outlined and imaged in a microcomputed tomography scanner to achieve 3D reconstructions of the accessible surface area. The study outcomes were accessible surface area of the talar dome in (1) total surface area and (2) sagittal plane distance of the talar dome at predetermined intervals. RESULTS: The PM approach provided significantly more access to the talar dome than did the PL approach both with and without distraction (P < 0.001). The PM approach allowed access to 15.8% (SD = 4.7) of the talar dome without distraction and 26.4% (SD = 8.0, P < 0.001) of the talar dome with distraction. The PL approach provided access to 6.69% (SD = 2.69, P = 0.006 compared with PM) and 14.6% (SD = 6.24, P = 0.006 compared with PM) of the talar dome surface area without and with distraction. At the difficult to access posterocentral region (L50) of the talus, the PM approach without and with distraction allowed 26.7% (SD = 4.1) and 38.6% (SD = 5.6, P < 0.001) sagittal plane access compared with 18.7% (SD = 5.61, P = 0.03) and 27.5% (SD = 7.11, P = 0.003) through a PL approach. CONCLUSION: The PM approach provides greater access to the posterocentral and PM talus. Using an external fixator for distraction can improve intraoperative visualization by at least 40%. This study provides a roadmap that can help guide talar dome surgical access for treatment of posterior talus fractures and help determine when an approach that includes an osteotomy can be avoided.

Anatomy and biomechanics of the Lisfranc ligamentous complex: A systematic literature review.

Lisfranc injuries are challenging to treat and can have a detrimental effect on active individuals. Over the past decade researchers have investigated methods for the reconstruction of the Lisfranc ligamentous complex (LLC) to preserve its functional stability and mobility. To aid in this innovation, this study presents the current understanding of the anatomical and biomechanical characteristics of the LLC through a systematic review. Three medical databases (PubMed, Scopus, and Embase) were searched from inception through July 2019. Original studies investigating the anatomy and/or biomechanical properties of the LLC were considered for inclusion. Data recorded from each study included: number of cadavers, number of feet, gender, laterality, age, type of specimen, measurement methods, reported ligamentous bundles, ligament origins and insertions, geometric characteristics, and biomechanical properties of the LLC. The Quality Appraisal for Cadaveric Studies (QUACS) scale was used to assess the methodologic quality of included articles. Eight cadaveric studies investigating the LLC were included out of 1204 screened articles. Most articles described the LLC as three distinct structures: the dorsal- (DLL), interosseous- (ILL), and plantar- (PLL) Lisfranc Ligaments. The ILL had the largest thickness and insertional area of osseous attachment. Biomechanically, the ILL also had the highest stiffness and resistance to load prior to failure when loaded parallel to its fiber orientation. Current knowledge of the anatomical and biomechanical properties of the LLC are presented and highlight its significant role of stabilizing the tarsometatarsal articulation. Appreciating the biomechanical characteristics of the ILL may improve clinical insight in managing LLC injuries.

Semi-automatic micro-CT segmentation of the midfoot using calibrated thresholds.

PURPOSE: In the field of skeletal research, accurate and reliable segmentation methods are necessary for quantitative micro-CT analysis to assess bone quality. We propose a method of semi-automatic image segmentation of the midfoot, using the cuneiform bones as a model, based on thresholds set by phantom calibration that allows reproducible results in low cortical thickness bones. METHODS: Manual and semi-automatic segmentation methods were compared in micro-CT scans of the medial and intermediate cuneiforms of 24 cadaveric specimens. The manual method used intensity thresholds, hole filling, and manual cleanup. The semi-automatic method utilized calibrated bone and soft tissue thresholds Boolean subtraction to cleanly identify edges before hole filling. Intra- and inter-rater reliability was tested for the semi-automatic method in all specimens. Mask volume and average bone mineral density (BMD) were measured for all masks, and the three-dimensional models were compared to the initial semi-automatic segmentation using an unsigned distance part comparison analysis. Segmentation methods were compared with paired t-tests with significance level 0.05, and reliability was analyzed by calculating intra-class correlation coefficients. RESULTS: There were statistically significant differences in mask volume and BMD between the manual and semi-automatic segmentation methods in both bones. The intra- and inter-reliability was excellent for mask volume and bone density in both bones. Part comparisons showed a higher maximum distance between surfaces for the manual segmentation than the repeat semi-automatic segmentations. CONCLUSION: We developed a semi-automatic micro-CT segmentation method based on calibrated thresholds. This method was designed specifically for use in bones with high rates of curvature and low cortical bone density, such as the cuneiforms, where traditional threshold-based segmentation is more challenging. Our method shows improvement over manual segmentation and was highly reliable, making it appropriate for use in quantitative micro-CT analysis.

Limitations of accessibility of the talar dome with different open surgical approaches.

PURPOSE: The aim of this study is to systematically review the current, relevant literature and provide a thorough understanding of the various open surgical approaches utilized to gain access to the talar dome for treatment of osteochondral lesions. Realizing the limits of access from soft tissue exposures and osteotomies, with and without external distraction, will help surgeons to select the appropriate approach for each individual clinical situation. METHODS: A literature search was performed using three major medical databases: PubMed (MEDLINE), Scopus, and Embase. The Quality Appraisal for Cadaveric Studies (QUACS) scale was used to assess the methodological quality of each included study. RESULTS: Of 3108 reviewed articles, nine cadaveric studies (113 limbs from 83 cadavers) evaluating the accessibility of the talar dome were included in the final analysis. Most of these (7/9 studies) investigated talar dome access in the context of treating osteochondral lesions of the talus (OLTs) requiring perpendicular visualization of the involved region. Five surgical approaches (anteromedial; AM, anterolateral; AL, posteromedial; PM, posterolateral; PL, and direct posterior via an Achilles tendon splitting; DP), four types of osteotomy (anterolateral tibial, medial malleolar, distal fibular, and plafondplasty), and two methods of distraction (Hintermann retractor and external fixator) were used among the included studies. The most commonly used methods quantified talar access in the sagittal plane (6/9 studies, 66.7%). The greatest exposure of the talar dome can be achieved perpendicularly by performing an additional malleolar osteotomy (90.9% for lateral, and 100% for medial). The methodological quality of all included studies was determined to be satisfactory. CONCLUSION: Gaining perpendicular access to the central portion of the talar dome, measured in the sagittal plane, has clear limitations via soft tissue approaches either medially or laterally from the anterior or posterior aspects of the ankle. It is possible to access a greater talar dome area in a non-perpendicular fashion, especially from the posterior soft tissue approach. Various types of osteotomies can provide greater accessibility to the talar dome. This systematic review can help surgeons to select the appropriate approach for treatment of OLTs in each individual patient preoperatively. LEVEL OF EVIDENCE: Level IV.

Can a fibular malunion be corrected by a Z-shaped fibular osteotomy?

BACKGROUND: The aim of this study was to assess the short-term clinical and radiographic outcomes in patients who underwent realigning Z­shaped fibular osteotomy. METHODS: Between January 2007 and December 2014, 28 patients with a painful fibular malunion underwent a Z-shaped realignment fibular osteotomy. The mean age was 42.2 ± 14.1 years (range 19.1-67.8 years) and the mean follow-up was 7.0 ± 1.7 years (range 4.0-9.7 years), with no loss to follow-up. Weight-bearing radiographs were used to determine the distal fibula alignment based on Weber's criteria. Degenerative changes of the tibiotalar joint were assessed using the Kellgren-Lawrence scale. Clinical assessment included pain evaluation, measurement of ankle range of motion (ROM), sports activities, and quality of life outcomes. RESULTS: There were no intraoperative or perioperative complications. No delayed unions or nonunions were observed. One patient had radiographic progression of degenerative changes in the tibiotalar joint. Postoperative complications included removal of hardware (n = 15) and arthroscopic tibiotalar joint debridement (n = 2). At the last follow-up the mean visual analog scale (VAS) decreased from 6.5 ± 1.1 to 2.1 ± 1.1 (p < 0.001),the ROM improved from 39ºâ€¯± 6º to 45ºâ€¯± 4.5º (p < 0.001), the short form health survey questionnaire (SF-36) physical and mental outcome scores improved from 49 ± 8 to 84 ± 7 (p < 0.001) and from 61 ± 4 to 83 ± 5 (p < 0.001), respectively. CONCLUSION: The Z­shaped realignment osteotomy of the distal fibula can provide pain relief and functional improvement in the treatment of fibular malunion. Further studies are needed to address long-term outcomes in this patient cohort.

Reliability of measurements assessing the Lisfranc joint using weightbearing computed tomography imaging.

INTRODUCTION: Subtle Lisfranc joint injuries remain challenging to diagnose in clinical practice. Although of questionable accuracy, bilateral weightbearing radiographs are considered the current gold standard to assess these injuries. However, weightbearing computed tomography (WBCT), which provides clearer visualization of bony landmarks, can also be used for evaluation. This study aims to design a protocol that reliably measures the distance between the medial cuneiform (C1) and second metatarsal (M2) to assess the Lisfranc joint using WBCT imaging. METHODS: Two unique methods of measuring the C1-M2 distance were designed that localize the center of the interosseous Lisfranc ligament (ILL, reference point). This reference point was located by (I) measuring a specific distance at the M2 base, or (II) approximating from nearby bony landmarks, on both axial (Ax) and coronal (Cor) WBCT images. Four parameters (I-Ax, I-Cor, II-Ax, and II-Cor) were evaluated for each of 96 specimens. Measurements were recorded by three independent observers and repeated for inter- and intra-observer agreement. RESULTS: In total, 96 patient image series were included and assessed in our study with an average age of 46 (19-66, SD 16.1) and average BMI of 25.8 (17.8-30.5, SD 4.3). I-Ax showed excellent agreement for intra-observer evaluation (R = 0.802) and good agreement for inter-observer evaluation (R = 0.727). I-Cor demonstrated excellent inter- (R = 0.814) and intra-observer (R = 0.840) agreement. Good agreement was found for both II-Ax and II-Cor for both intra- (R = 0.730, R = 0.708) and inter-observer (R = 0.705, R = 0.645) evaluation. CONCLUSION: Measuring the C1-M2 joint space with coronal WBCT imaging through a protocol that localizes the ILL is reproducible, simple, and can potentially be utilized clinically to evaluate the Lisfranc joint.

3D Assessment in Posttraumatic Ankle Osteoarthritis.

BACKGROUND: Auto-generated 3-dimensional (3D) measurements based on weightbearing cone-beam computed tomography (CT) scan technology may allow for a more accurate hind- and midfoot assessment. The current study evaluated the reliability and clinical relevance of such measurements in patients with posttraumatic end-stage ankle osteoarthritis. METHODS: Seventy-two patients treated at our institution for posttraumatic end-stage ankle osteoarthritis, with available weightbearing conventional radiographs and a cone-beam CT scan, were analyzed. Twenty healthy individuals aged between 40 and 70 years served as controls. Seven variables were measured on weightbearing conventional radiographs (2D) and compared to 3D measurements that were based on reconstructions from weightbearing cone-beam CT scans. The reliability of each measurement was calculated and subgroups formed according to commonly observed deformities. RESULTS: Inter- and intraobserver reliability was superior for 3D compared to 2D measurements. The accuracy of 3D measurements performed on osteoarthritic ankles was similar to 3D measurements performed on healthy individuals. Thirty-three of the 72 included patients (46%) evidenced an inframalleolar compensation of a supramalleolar/intra-articular ankle deformity (78% = varus compensation; 22% = valgus compensation), whereas 24 of those 72 patients (33%) showed no compensation or a further increase of a supramalleolar/intra-articular ankle deformity (67% = varus deformity; 33% = valgus deformity). CONCLUSION: Auto-generated 3D measurements of the hind- and midfoot were found to be reliable in both healthy individuals and patients with posttraumatic end-stage ankle osteoarthritis. Such measurements may be crucial for a detailed understanding of the location and extent of hindfoot deformities, possibly impacting decision making in the treatment of end-stage ankle osteoarthritis. LEVEL OF EVIDENCE: Level III, comparative study.

Comparative assessment of midfoot osteoarthritis diagnostic sensitivity using weightbearing computed tomography vs weightbearing plain radiography.

PURPOSE: Accuracy in diagnosing osteoarthritis in the midfoot using weightbearing plain radiography (WBPR) remains questionable due to the overlapping osseous architecture present, occluding visualization. Weightbearing computed tomography (WBCT), providing clearer bony landmark identification and joint space visualization, can also be used for evaluation. The aim of this project is to perform a standardized retrospective intra-patient analysis identifying the discrepancy of midfoot osteoarthritis diagnosis and osteoarthritis severity grading between WBPR and WBCT. METHODS AND MATERIALS: A cohort of 302 patient feet was acquired from an internal, consecutive patient database using detailed inclusion criteria. The musculoskeletal radiologist interpretation of the WBCT and WBPR of each specimen was then assessed for any direct diagnosis or mention of osteoarthritic signs in specific articulations of 3 midfoot joint groups (Chopart, "central", and tarsometatarsal). WBPR sensitivity and specificity metrics were calculated with WBCT considered the gold standard for comparison. RESULTS: From the WBPR radiologist interpretation, we found diagnostic sensitivity of 72.5 % and specificity of 87.9 % for Chopart joints; 61.5 % sensitivity, and 96.1 % specificity for central joints; and 68.4 % sensitivity, and 92.9 % specificity for tarsometatarsal joints. The severity of degenerative changes was also consistently underestimated when interpreted from WBPR relative to WBCT. CONCLUSIONS: In this series, midfoot osteoarthritis was often undetected on WBPR. WBCT imaging facilitates an earlier, more reliable diagnosis and grading of midfoot osteoarthritis relative to WBPR.

Change in the First Cuneiform-Second Metatarsal Distance After Simulated Ligamentous Lisfranc Injury Evaluated by Weightbearing CT Scans.

BACKGROUND: This study aimed to investigate the widening between the first cuneiform (C1) and second metatarsal (M2) in a Lisfranc ligamentous complex (LLC) joint injury model subjected to successive ligament dissections evaluated by weightbearing computed tomography (CT) scans. METHODS: Twenty-four intact cadaveric feet served as the control (condition 1). Each component of the LLC (dorsal, interosseous, and plantar ligaments-conditions 2, 3, and 4, respectively) were then sequentially dissected. The specimens were equally randomized to 1 of 3 additional dissections (first or second tarsometatarsal [TMT] joint capsule or first-second intercuneiform ligament [ICL]-conditions 5a, 5b, and 5c, respectively). One additional ligament was then randomly transected (eg, condition 6ac-transection of the first TMT capsule and ICL). Finally, the remaining ligament was transected (condition 7). After each dissection, CT scans were acquired under nonweightbearing (NWB, 0 kg), partial-weightbearing (PWB, 40 kg), and full-weightbearing (FWB, 80 kg) conditions. The distance between the lateral border of C1 and the medial border of M2 was assessed to evaluate diastasis. Linear regressions with 95% CIs and converted q values were used to compare the measured data. RESULTS: No significant differences were found within the control. In condition 4, an average axial plane widening relative to control of 1.6 mm (95% CI, 1.5-1.8) and 2.1 mm (95% CI, 1.9-2.2) was observed under PWB and FWB. A coronal plane widening of 1.5 mm (95% CI, 1.3-1.6) and 1.9 mm (95% CI, 1.7-2.1) under PWB and FWB, respectively, was measured. A 95% CI of at least a 2-mm widening during PWB was demonstrated in 5c, 6ac, 6bc, and 7. CONCLUSIONS: Weightbearing computed tomography (WBCT) scans were used to detect ligamentous Lisfranc injuries in a cadaveric model. Relative axial widening greater than 1.5 mm under PWB conditions could indicate a complete LLC injury. Complete transection of the intercuneiform 1-2 ligament was required to detect a 2-mm widening in the nonweightbearing condition. CLINICAL RELEVANCE: This study provides insight on the detection of various severities of LLC injuries using WBCT imaging.

Asymmetric lambda sign of the second tarsometatarsal joint on axial weight-bearing cone-beam CT scans of the foot: preliminary investigation for diagnosis of subtle ligamentous Lisfranc injuries in a cadaveric model.

BACKGROUND: Subtle Lisfranc joint injuries remain challenging to diagnose. Although of questionable accuracy, the current gold standard to assess these injuries is through bilateral weight-bearing radiography. However, weight-bearing cone beam-computed tomography (CBCT), providing clearer visualization of bony landmarks, can also be utilized for evaluation. This study aims to establish the hypothesis that a specific weight-bearing CBCT finding (asymmetric lambda sign) can serve as an independent indicator of a subtle Lisfranc injury. METHODS: Weight-bearing CBCT images of 24 match-paired cadaveric legs were acquired, initially intact, and then following sequential dissection of each aspect (dorsal, interosseous, and plantar ligaments, respectively) of the Lisfranc ligamentous complex (LLC). All scans were taken in non- (NWB, 0 kg), partial- (PWB, 40 kg), and full-weight-bearing (FWB, 80 kg) manners. The lambda sign was then inspected axially for asymmetry (positive sign) by identifying three symmetrical joint spaces created between the medial cuneiform and the second metatarsal base (C1-M2), the medial and middle cuneiform (C1-C2), and the second metatarsal base and middle cuneiform (M2-C2). RESULTS: A positive sign was observed in 25.6% (221/864) of all studies. Most notably, the fully dissected specimens demonstrated an asymmetric lambda sign in 33.3%, 72.2%, and 83.3% in NWB, PWB, and FWB conditions, respectively. The inter- and intra-observer reliability kappa value was calculated to be 0.843 and 0.912. CONCLUSION: An asymmetric lambda sign is a simple and useful indicator for a complete LLC injury in PWB and FWB conditions using a cadaver model.

Surgical outcome of chronic Lisfranc injury without secondary degenerative arthritis: A systematic literature review✰.

BACKGROUND: Chronic Lisfranc joint injuries (tarsometatarsal, TMT) can present as a variety of clinical symptoms and radiographic findings. If significant arthritis at the Lisfranc joint is present, salvage arthrodesis is an option. For patients who receive a delayed diagnosis and/or present with no signs of arthritic changes, selecting the most appropriate treatment can be challenging. This article provides a systematic review of current surgical treatment options and outcomes for patients with a chronic Lisfranc injury but no secondary degenerative changes. METHODS: Four major medical databases were searched from inception through March 5, 2019: PubMed, Science Direct, Scopus, and Embase. Studies were included if they were original research studies that assessed the outcome of patients treated surgically for chronic Lisfranc injuries without secondary osteoarthritic changes. Only studies written in English and German were considered. The following data were recorded from each study: number of patients and feet included, study design (prospective vs. retrospective, single vs. multicenter, level of evidence), time between initial injury and operation, operative techniques, age, mechanism of injury, type of injury (purely ligamentous or ligamentous with concomitant bony fractures), indications for surgery, pre-operative assessment, postoperative follow-up time, time to return to activity or sport, and clinical outcome. The modified Coleman Score was used to assess the methodologic quality of the included studies. RESULTS: Of the 6,845 screened, ten studies met the above criteria and were included. All but one were single center studies. All studies were either retrospective or prospective case series. Overall, studies generally reported low complication rates and good functional outcomes. Postoperative outcomes were most frequently measured with the American Orthopaedic Foot and Ankle (AOFAS) score; the overall mean preoperative AOFAS scores of 55.7 significantly improved to 88.1 at final follow-up. CONCLUSIONS: No definitive consensus exists on how Lisfranc instability without concurrent osteoarthritis should be surgically managed. Despite the delay in diagnosis, patients who undergo surgical repair for chronic, unstable Lisfranc injury without osteoarthritis have improved patient outcome and few post-surgical complications. While the quality of these studies is satisfactory, a larger patient cohort and prospective analysis could further strengthen arguments for or against certain surgeries. LEVEL OF EVIDENCE: Level IV; Systematic Review of Level IV Studies.

Imaging in Lisfranc injury: a systematic literature review.

OBJECTIVES: To systematically review current diagnostic imaging options for assessment of the Lisfranc joint. MATERIALS AND METHODS: PubMed and ScienceDirect were systematically searched. Thirty articles were subdivided by imaging modality: conventional radiography (17 articles), ultrasonography (six articles), computed tomography (CT) (four articles), and magnetic resonance imaging (MRI) (11 articles). Some articles discussed multiple modalities. The following data were extracted: imaging modality, measurement methods, participant number, sensitivity, specificity, and measurement technique accuracy. Methodological quality was assessed by the QUADAS-2 tool. RESULTS: Conventional radiography commonly assesses Lisfranc injuries by evaluating the distance between either the first and second metatarsal base (M1-M2) or the medial cuneiform and second metatarsal base (C1-M2) and the congruence between each metatarsal base and its connecting tarsal bone. For ultrasonography, C1-M2 distance and dorsal Lisfranc ligament (DLL) length and thickness are evaluated. CT clarifies tarsometatarsal (TMT) joint alignment and occult fractures obscured on radiographs. Most MRI studies assessed Lisfranc ligament integrity. Overall, included studies show low bias for all domains except patient selection and are applicable to daily practice. CONCLUSIONS: While conventional radiography can demonstrate frank diastasis at the TMT joints; applying weightbearing can improve the viewer's capacity to detect subtle Lisfranc injury by radiography. Although ultrasonography can evaluate the DLL, its accuracy for diagnosing Lisfranc instability remains unproven. CT is more beneficial than radiography for detecting non-displaced fractures and minimal osseous subluxation. MRI is clearly the best for detecting ligament abnormalities; however, its utility for detecting subtle Lisfranc instability needs further investigation. Overall, the available studies' methodological quality was satisfactory.