CT assessment of the prevalence of retinacular injuries associated with hindfoot fractures

The effect of spanning external fixation on entrapped structures in tibial pilon fractures

PURPOSE

Pilon fractures are often complex injuries involving severe soft tissue injury. Studies have shown pilon fractures may entrap soft tissue structures between fracture fragments. Staged fixation of pilon fractures with spanning external fixation (SEF) is important for soft tissue rest and plays an important role in the management of these injuries. While SEF has been shown to promote soft tissue rest prior to definitive fixation, no studies have shown the effect SEF has on entrapped structures (ES). The purpose of this study was to evaluate how SEF effects ES in pilon fractures.

METHODS

A retrospective review of 212 pilon fractures treated at our institution between 2010 and 2022 was performed. Patients with a CT scan pre-SEF and post-SEF met inclusion criteria. CTs were reviewed to characterize ES in pre- and post-SEF imaging.

RESULTS

Of the 19 patients with ES identified on CT pre-SEF, seven (36.8%) had full release of ES post-SEF and 12 (63.2%) had no release of ES. The posterior tibial tendon was the most commonly ES and remained entrapped in 62.5% of cases. Only 25% of 43-C3 fractures had release of ES post-SEF, while 100% of 43-C1 and 43-C2 fractures demonstrated complete release of ES post-SEF.

CONCLUSION

Entrapped structures in pilon fractures are likely to remain entrapped post-SEF, with only one-third of our cohort demonstrating release. In 43-C3 patterns, if ES are identified on CT pre-SEF, surgeons should consider addressing these either through mini open versus open approaches at the time of SEF as they are likely to remain entrapped post-SEF.

Incidence and clinical results of tendinous injuries in calcaneus and pilon fractures

PURPOSE

The aims of this study were: (1) to define the incidence of tendinous injuries in calcaneus and pilon fractures with different fracture severity and (2) to determine the clinical impact of such injuries.

STUDY DESIGN AND METHODS

CT-scans of 121 patients with calcaneus and pilon fractures were retrospectively analyzed over a 4-year period. The tendinous injuries were identified and correlated with the type of fracture (location and classification). Clinical analysis was performed using the American Orthopedic Foot and Ankle Society (AOFAS) and SF-36 (Short Form-36 Health Survey) scores.

RESULTS

Tendinous injuries were observed in 36% of all CT-scans analyzed, with the most common injury being incarceration (n = 20) and dislocation (n = 24). Calcaneus fractures sanders type 3/4 were 9 times more prone to tendon injury (p < 0.001; OR 8.67; 95% CI 2.49-30.24). Pilon fractures Ruedi-Allgower type 2/3 were 8 times more prone to tendon injury (p = 0.005; OR 7.5; 95% CI 1.72-32.80). No significant differences (p > 0.05) were found in AOFAS and SF-36 scores between patients with/without tendon injuries for fractures with the same severity.

CONCLUSION

The incidence of tendon injuries in calcaneus/pilon fractures is high and may be underreported. Calcaneus fractures are prone to peroneal tendon injury. In pilon fractures, it is important to look for tibialis posterior tendon injury, especially entrapment. The presence of tendinous injuries does not affect function and pain for the same type of calcaneus and pilon fractures at the long term.

LEVEL OF EVIDENCE

Level 3 retrospective study.

Hindfoot Fractures: Injury Patterns and Relevant Imaging Findings

The hindfoot consists of the talus and calcaneus, spans the tibiotalar to transverse tarsal joints, and is critical for support of body weight and absorption and transfer of physiologic loads during bipedal movements. Hindfoot fractures account for approximately 17% of foot and ankle fractures, with calcaneal fractures being more common than talar fractures. Hindfoot fractures are usually caused by high-impact axial loads such as falls from heights and motor vehicle accidents, and understandably, they are often seen in patients with polytrauma. Long term, these fractures have implications in development of posttraumatic osteoarthrosis with associated pain and stiffness, affecting daily living activities. An overview of the talus and calcaneus is presented, with emphasis on fractures with articular involvement-namely, the tibiotalar and subtalar joints. Articular talar and calcaneal injuries can also alter hindfoot alignment, causing ankle and foot function abnormalities. Optimal treatment-that is, restoration of articular surfaces and hindfoot alignment followed by rigid fixation until fracture union-is dependent on an accurate understanding of the injury that is well depicted with imaging, radiography and CT in particular. The discussion of talar and calcaneal fractures includes a review of the normal anatomy, epidemiologic factors, classification systems, and imaging and pathologic-anatomic features of common injury patterns. This review is intended to aid surgical management and restoration of articular and hindfoot alignment for optimal ankle and foot function, thereby reducing patient morbidity in these often devastating injuries. ^©RSNA, 2022.

Influence of tendon injuries on the clinical outcome of ankle and hindfoot fractures

BACKGROUND

Associations of tendon injuries with ankle and hindfoot fractures is a current concern and recent research has linked specific fractures with specific tendon injuries, despite its functional impact being unknown. The purpose of this study is to assess that impact.

METHODS

Computed tomography scans of patients with ankle and hindfoot fractures were reviewed for tendon injuries. Patients were clinically evaluated with the Visual Analogue Scale (VAS) and the Manchester-Oxford Foot Questionnaire (MOXFQ), via a telephonic interview.

RESULTS

Eighty-five patients were included in the study. The mean age was of 49.9 ± 16.5 (14-80) years and there were 43 females (50,6%). Mean follow-up was of 43,7 ± 15,1 (24,4-82,2) months. Tendon injuries were identified in 23 patients (27,1%) and the most common lesion was tendon entrapment. The tibialis posterior tendon (TP) was injured in 18 patients (21,2%) and comprised 58,1% of all tendon injuries. Tendon injuries were mostly associated with pilon fractures, which was the most common fracture type (44,7%). There was no clinical difference between patients with a tendon injury [VAS of 4,3 ± 2,6 (0-8) and MOXFQ score of 35,1 ± 22,4 (5-80)], and those without [VAS of 3,9 ± 2,5 (0-10) and MOXFQ of 34,3 ± 26,0 (0-95), respectively (p = 0,281 and 0,689)].

CONCLUSION

Tendon injuries were present in 27% of patients with ankle and hindfoot injuries. The most frequently injured tendon was the TP in association with pilon fractures, with entrapment being the most common lesion. These lesions, however, do not seem to reflect in a worse functional outcome at two years of follow-up.

Evaluation of ankle ligaments with CT: A feasibility study

PURPOSE

This study aims to systematically investigate if normal ankle ligaments can be assessed with CT imaging, using MRI as reference standard.

METHODS

35 patients (mean age: 47 ± 15 years; female n = 19) with combined CT and MRI exams and without MR-morphologic signs of ankle ligamental injury were retrospectively identified. 3 readers independently evaluated the syndesmotic, the lateral and medial ankle ligaments in terms of visibility on a 4-point Likert scale (0-3 points) in multiplanar MDCT images in standard bone kernel reconstructions. In consensus CT-based ligament density and thickness were measured and the appearance was rated for each ligament. Results were compared and validated with corresponding MRI images.

RESULTS

Almost all ankle ligaments identified in MRI images could be adequately depicted in standard multiplanar bone kernel CT images with a mean visual score of 2.7/3 (± 0.2). Difficulties in CT morphological delineation of ankle ligaments occurred in cases of filiform TNL and TCL and in cases of concurrent soft tissue edema. Interreader agreement for the CT-assessment of ankle ligaments was excellent, with Fleiss Kappa values >0.8. Mean density of evaluated medial and lateral ankle ligaments was 68 ± 2.9 HU, with substantially inter- and intraindividual variations. Thickness measurements and assessment of appearance of ankle ligaments showed a good concordance between CT and MRI.

CONCLUSIONS

Assessment of normal ankle ligaments via standard CT in bone kernel reconstructions is feasible, with some restrictions concerning the medial collateral ligaments and in the presence of soft tissue edema.

Anteroposterior Radiograph of the Ankle with Cross-Sectional Imaging Correlation

The focus of this article is to illustrate various pathologic entities and variants, heralding disease about the ankle, based on scrutiny of AP radiographs of the ankle, with correlative findings on cross-sectional imaging. Many of these entities can only be detected on the AP ankle radiograph and, if not recognized, may lead to delayed diagnosis and persistent morbidity to the patient. However, a vigilant radiologist, equipped with the knowledge of the characteristic appearance and typical locations of the imaging findings, should be able to make the crucial initial diagnosis and surmise additional findings to be confirmed on cross-sectional imaging.

CT can stratify patients as low risk for tibial neuropathy following a talus fracture

OBJECTIVE

Determine the incidence of tibial neuropathy following talus fractures and CT's ability to stratify patients at risk for developing post-traumatic neuropathy.

MATERIALS AND METHODS

In this IRB-approved retrospective analysis, 71 talus fractures and 8 contralateral control ankle CTs were reviewed by one observer blinded to clinical information. CT evidence suggestive of tibial neurovascular bundle injury included nerve displacement, perineural fat effacement/edema, and bone touching nerve. The association between these CT findings and clinically evident tibial neuropathy was analyzed. A semi-quantitative likelihood score was assigned based on the degree of the CT findings around the nerve. Interobserver agreement was calculated between 2 other readers.

RESULTS

Twenty-five percent of patients in this cohort had clinical evidence of tibial neuropathy. There was a high specificity (0.87-0.93) and negative predictive value (0.83-0.87), a moderate accuracy (0.80-0.82), but a lower sensitivity (0.33-0.56) associated with the CT findings. Among the CT findings, nerve displacement (p < 0.0001) and bone touching nerve (p = 0.01) were associated with tibial neuropathy. A likelihood score of 2-5 was associated (p = 0.007-0.015) with tibial neuropathy. The presence of tibial neuropathy and nerve recovery were not associated with hospital length of stay, while CT findings were. There was substantial agreement between the three readers: likelihood scores 2+ (k = 0.78) and 3+ (k = 0.72).

CONCLUSIONS

Tibial neuropathy occurs following talus fractures, and CT findings may help surgeons narrow down the number of patients requiring close neurological follow-up.

Traction radiographs versus CT in the evaluation of fracture morphology and consecutive treatment decisions in OTA/AO 43C3 fractures

BACKGROUND

Standard radiographs are limited in the evaluation of fracture characteristics and preoperative planning of OTA/AO 43C3 fractures. Therefore, CT imaging is an accepted as a useful method. CT is however expensive and has high radiation, and traction radiographs could be an alternative. This study aimed to compare fracture fragment and comminution zone visualization between traction radiographs and CT and any potentially resulting differences in consecutive treatment and surgical approach recommendations.

METHODS

Twenty orthopaedic surgeons assessed traction radiographs and CT images of 12 OTA/AO 43C3 type fractures. Each observer was required to identify the anterolateral, posterolateral, and medial malleolus fragments and the lateral, central, and medial shoulder comminution zones. They then had to recommend treatment (nonoperative, ORIF, closed reduction and external fixation, percutaneous screw fixation, or primary tibiotalar arthrodesis) with the best surgical approach (medial, anterolateral, posterolateral, posteromedial, or combined). Intra- and interobserver reliability, correct identification of fracture fragments and comminution zones on both images, and consistency of treatment recommendations and surgical approaches were analyzed.

RESULTS

The agreement of each observer's assessment of the presence or absence of specific fracture fragments and comminution zones was substantially increased for CT as compared to traction radiographs, particularly for the posterolateral (p = 0.000) and anterolateral fragment (p = 0.000), and the lateral (p = 0.000), central (p = 0.000), and medial shoulder comminution zone (p = 0.000). The interobserver reliability when assessing the three fracture fragments and comminution zones on the traction radiographs was moderate, whereas it was substantial when assessing these characteristics on CT. The medial malleolus fragment was more often correctly identified on traction radiographs than CT images (p = 0.001). The ability to correctly identify lateral, central, and medial shoulder comminution zones was higher for CT than traction radiographs (p = 0.000). The treatment and surgical approach recommendations after traction radiograph and CT evaluation were similar (p < 0.05).

CONCLUSIONS

Traction radiographs may be a useful alternative to CT imaging in the preoperative planning of pilon fracture repair. Despite less reliable fracture fragment and comminution zone identification on traction radiographs, treatment recommendations and surgical approach were not influenced.

Prevalence of Peroneal Tendon Instability in Calcaneus Fractures: A Systematic Review and Meta-Analysis

Peroneal tendon instability associated with an intraarticular calcaneal fracture is a common injury that still often passes undiscovered by both radiologists and orthopedic surgeons. Timely identification of this injury will guide the choice of surgical technique used and treatment of patients. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, several databases were searched through June 2017 for any observational or experimental studies that reported the prevalence/incidence of peroneal tendon subluxation/dislocation with a calcaneus fracture with regard to fracture classifications and the significance of the fleck sign. Nine studies were included, with 1027 patients and 1050 calcaneus fractures. The overall prevalence of peroneal instability (PI) in association with a calcaneus fracture was 29.3%. An increasing prevalence of PI increased the severity of the calcaneus fractures, 5.4% in Sanders I, 19% in Sanders II, 39.4% in Sanders III, and 49.5% in Sanders IV. The presence of a fleck sign is a strong indicator of PI, with a prevalence of 54.7%. The computed tomography findings can overestimate the presence of PI compared with the intraoperative findings. The global reported prevalence of peroneal tendon instability associated with intraarticular calcaneal fractures is high and increases with increasing severity of the calcaneus fracture.

Computed Tomography Assessment of Peroneal Tendon Displacement and Posteromedial Structure Entrapment in Pilon Fractures

OBJECTIVES

To determine the proportion of (1) peroneal tendon displacement (PTD) and posteromedial structure entrapment (PMSE) cases in a sample of pilon fractures, (2) missed diagnoses of PTD and PMSE on computed tomography (CT) by radiologists and attending orthopaedic trauma surgeons, and PTD and PMSE cases by (3) OTA/AO classification, and (4) fibular fracture.

DESIGN

Retrospective cohort review.

SETTING

Regional level 1 Trauma Center.

PATIENTS/PARTICIPANTS

Two hundred patients treated between July 2008 and November 2014.

INTERVENTION

Axial and reconstructed CT images were used in bone and soft tissue windows to identify PTD and PMSE.

MAIN OUTCOME MEASUREMENTS

Medical charts were reviewed to identify OTA/AO fracture classification, the presence of concomitant fibular fracture, whether radiologist CT interpretation noted PTD or PMSE, and whether attending orthopaedic trauma surgeons' operative notes mentioned recognition of and management of PTD or PMSE.

RESULTS

From the retrospective review of CT, PTD was identified in 11.0% and PMSE in 19.0% of all pilon fractures. Of the 22 patients with PTD, 59.1% sustained a concomitant fibular fracture and 90.9% sustained a 43-C fracture. Patients with PTD sustained more 43-C fractures (90.9% vs. 62.9%) but significantly fewer fibular fractures (59.1% vs. 80.3%; P = 0.023) than patients without PTD. Of the 38 patients with PMSE, 81.6% sustained a fibular fracture and 86.8% sustained a 43-C fracture. PMSE was more common in patients with 43-C fractures (86.8% vs. 61.1%). The final preoperative radiologist CT interpretation commented on PTD and PMSE in 50.0% of cases.

CONCLUSIONS

Higher energy pilon fractures (43-C) are associated with higher incidence of PMSE and PTD. Concomitant fibula fracture may play a protective role in PTD in the setting of pilon fractures. Both attending radiologists and attending orthopaedic trauma surgeons frequently fail to recognize the diagnoses of PTD and PMSE.

LEVEL OF EVIDENCE

Prognostic level III. See Instructions for Authors for a complete description of levels of evidence.

Medial-sided Ankle Pain: Deltoid Ligament and Beyond

Abnormalities of the medial ligaments and posterior tibial tendon can occur because of acute injury or chronic instability or malalignment. Medial ankle injuries may occur because of pronation or supination-external rotation injuries. Deltoid ligament injuries have a significant impact on lateral ankle instability but can be overlooked in patients with lateral ligament injuries. Posterior tibial tendon dysfunction is usually associated with spring ligament or flexor retinaculum injury. Tarsal tunnel syndrome, accessory flexor muscles, and subtalar coalition should be considered as well as ligament and tendon tears in differential diagnosis of chronic medial ankle pain.

Ultrasound Guidance in Performing a Tendoscopic Surgery to Treat Posterior Tibial Tendinitis: A Useful Tool?

A 25-year-old man with a pronation-external rotation type of fracture was surgically treated using a fibular plate. Five years later, he underwent resection of bone hyperplasia because of the ankle pain and limitation of range of motion. Thereafter, the left ankle became intermittently painful, which persisted for about one year. He presented at the age of 43 with persistent ankle pain. Physical and image analysis findings indicated a diagnosis of posttraumatic posterior tibial tendinitis, which we surgically treated using tendoscopy. Endoscopic findings showed tenosynovitis and fibrillation on the tendon surface. We cleaned and removed the synovium surrounding the tendon and deepened the posterior tibial tendon groove to allow sufficient space for the posterior tibial tendon. Full weight-bearing ambulation was permitted one day after surgery and he returned to his occupation in the construction industry six weeks after surgery. The medial aspect of the ankle was free of pain and symptoms at a review two years after surgery. Although tendoscopic surgery for stage 1 posterior tibial tendon dysfunction has been reported, tendoscopic surgery to treat posttraumatic posterior tibial tendinitis has not. Our experience with this patient showed that tendoscopic surgery is useful not only for stage 1 posterior tibial dysfunction, but also for posttraumatic posterior tibial tendinitis.

Incidence of tendon entrapment and dislocation with calcaneus and pilon fractures on CT examination

OBJECTIVE

To examine the association between tibial pilon and calcaneal fracture classification and tendon entrapment or dislocation.

MATERIALS AND METHODS

After institutional review board approval, we retrospectively reviewed consecutive CT scans with calcaneal or pilon fractures from 5 years at a level 1 trauma center. We categorized calcaneal fractures according to the Sanders classification, and pilon fractures according to the Ruedi and Allgower and the Arbeitsgemeinschaft für Osteosynthesefragen-Orthopaedic Trauma Association (AO-OTA) classifications. Ankle tendons were assessed for dislocation or entrapment. Fisher's exact test was used for statistical analysis with significance at p < 0.05.

RESULTS

A total of 312 fractures (91 pilon only, 193 calcaneal only, and 14 ankles with ipsilateral pilon and calcaneal fractures) were identified in 273 patients. Twenty-two pilon, 42 calcaneal, and nine combination fractures were associated with 99 occurrences of tendon entrapment or superior peroneal retinacular injury. Such findings were associated with multiple fractures (p = 0.002). Multifragmentary pilon fractures were associated with posterior tibial and flexor digitorum longus tendon entrapment (p < 0.0001 and p = 0.0003 for Ruedi/Allgower and AO-OTA, respectively), and multifragmentary Sanders type 3 or 4 calcaneal fractures were associated with superior peroneal retinacular injury (p = 0.0473) compared to simple fracture patterns. Thirty-nine percent of tendon entrapments or retinacular injuries were prospectively identified, 85 % by musculoskeletal radiologists (p < 0.0001).

CONCLUSIONS

Approximately 25 % of calcaneal and pilon fractures were retrospectively identified to contain posteromedial tendon entrapment or superior peroneal retinacular injury. Radiologists should meticulously search for such injuries, particularly when analyzing multifragmentary and multiple fractures.