Entrapped posteromedial structures in pilon fractures

Tibialis posterior tendon entrapment in posterior malleolar and pilon injuries of the ankle: a retrospective analysis

BACKGROUND

The Tibialis Posterior tendon (TPT) is the only tendon to encounter the distal tibia and is therefore at greatest risk of injury in fractures of the distal tibia. Although TPT injury has been reported rarely with injuries around the ankle, they often have been missed and present late.

AIM

Our aim was to analyse the rate to TPT entrapment in fractures involving the posterior tibia, i.e. Pilon (PLM) and posterior malleolar fractures (PMF).

METHODS

A retrospective analysis of PMF and Pilon fractures over an 8-year period was undertaken. Patients who had undergone surgical fixation of their PMF or PLM were identified from 2014 to 2022, using our prospectively collected database. Any fracture which had undergone a preoperative CT was included. Analysis of their pre-operative CT imaging was utilised to identify TPT entrapment, where if < 50% of the tendon cross section was present in the fracture site, this was denoted as a minor entrapment and if ≥ 50% of the tendon was present in the fracture site was denoted as major.

RESULTS

A total of 363 patients were identified for further analysis, 220 who had a PMF and 143 with PLM injury. The incidence of TPT entrapment was 22% (n = 79) with 64 minor and 15 major entrapments. If the fracture line entered the TPT sheath, there was a 45% rate (72/172) of entrapment as compared to 3.7% (7/190) in fractures not entering the sheath (p < .001). There was no significant difference in TPT entrapment in PMF as compared to PML (p = 0.353).

CONCLUSION

In our assessment, we found significant prevalence of 22% of TPT entrapment in fractures involving the posterior tibia. PMF and PLF had no statistically significant difference in the rate of TPT entrapment. Additionally, we found that there was a significant risk of TPT entrapment when the CT images display the fracture line entering the tendon sheath. We recommend that surgeons consider taking care assessing pre-operative imaging to seek to identify the TPT and to assess intraoperatively where entrapment does occur.

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.

Presurgical Perspective and Postsurgical Evaluation of Tibial Pilon Fractures

Tibial pilon fractures represent only a small percentage of all fractures of the lower limb. But they are a feared entity, both for the interpreting radiologist and the treating surgeon and, ultimately, for the patient because they involve the weight-bearing area of the joint and often have associated soft tissue injury. These factors make them technically challenging, with poor clinical and functional results in many patients, even when a perfect joint reduction is achieved. Presurgical evaluation with computed tomography and individualized staged management is critical for the prognosis, a definitive treatment strategy, and the prevention of future complications.

Anterior Compartment Neurovascular Bundle Entrapment in a Minimally Displaced Distal Tibial Fracture: A Case Report

CASE

A 29-year-old woman presented with a low-energy, minimally displaced pilon fracture with progressive pain and paresthesias in the affected foot, ultimately requiring open reduction and internal fixation. Intraoperatively, the deep peroneal nerve and anterior tibial artery and vein were entrapped within the fracture. After freeing the bundle and fixing the fracture, the paresthesias improved and ultimately resolved.

CONCLUSION

Injury to the anterior leg compartment neurovascular structures should be considered in low-energy, minimally displaced pilon fractures. In this instance, progressive neurologic symptoms not consistent with the radiographic findings indicated the patient for surgical exploration and fixation.

Sciatic Nerve Entrapment and Transection in a Combined Pelvic Ring-Acetabular Fracture: A Case Report

CASE

A traumatic sciatic nerve entrapment and transection because of a combined pelvic ring injury and acetabular fracture has never previously been described. We report such a case of a 32-year-old man who was found intraoperatively to have entrapment and transection of the sciatic nerve within the acetabular fracture.

CONCLUSION

Consideration for urgent intervention should be given to patients who present with a sciatic nerve palsy in the setting of certain acetabular fracture patterns with residual posterior column displacement. Early recognition and intervention with neurolysis may help provide the best environment for recovery.

An Unexpected Intra-operative Encounter of Anterior Tibial Vessels Entrapment in the Fracture of Tibial Pilon: A Case Report and Literature Review

We present a rare case of a comminuted tibial pilon fracture with entrapment of anterior tibial vessels in fracture site, which was unexpectedly discovered intra-operatively. Following safe extrication of vessels and fracture fixation through minimally invasive approach, the patient recovered uneventfully. Phenomenon of anterior neurovascular entrapment should be kept in mind while dealing with high-energy tibial pilon fractures. Astute clinical examination, judicious use of imaging modality, and strict intra-operative vigilance are key to successful outcome.

Comparison of four posterior approaches of the ankle: A cadaveric study

OBJECTIVES

The purpose of this study is to provide a detailed comparison of 4 posterior approaches of the ankle: the posteromedial, modified posteromedial (mPM), Achilles tendon-splitting (TS), and posterolateral approaches.

METHODS

Cadaveric dissections were performed to assess the influence of the medial and lateral retraction forces on the neuro-vascular bundle with suspension scales and to measure the medial and lateral exposed areas of the posterior tibia and talus. Data was acquired with the ankle in neutral position and in plantar flexion.

RESULTS

Both the mPM and TS approaches provided excellent visualization of the posterior tibia with the ankle in plantar flexion (16.6 cm2 and 16.2 cm2, respectively). The medial aspect of the posterior tibia, however, was significantly better exposed in the mPM approach than in the TS approach with the ankle in neutral position (8.9 cm2 vs 6.5 cm2). The lower value for medial retraction force in the mPM approach (1.9 N in neutral position and 0.9 N in plantar flexion) indicated a lower risk of injury to the neuro-vascular bundle (the tibial nerve and the posterior tibial artery). The posterior talus, however, is best visualized through the TS approach with the ankle in neutral position (4.5 cm2).

CONCLUSIONS

The current study demonstrated the usefulness of the mPM approach. When internal fixation of the fibula is unnecessary, the mPM approach is preferable, considering the potential damage to the Achilles tendon associated with the TS approach.

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.

Evolution in Management of Tibial Pilon Fractures

PURPOSE OF REVIEW

Tibial plafond, or pilon, fractures can be some of the most difficult fractures to manage. As they are often associated with high-energy trauma, both the soft tissue involvement and the comminuted fracture pattern pose challenges to fixation. Furthermore, the complex anatomy and trauma to the cartilage at the time of injury predispose pilon fractures to poor functional outcomes and high rates of posttraumatic arthritis. This review will discuss the recent developments in the treatment of tibial pilon fractures.

RECENT FINDINGS

Historically, surgical management of pilon fractures has been associated with high rates of complications, including wound complications, infections, nonunions, and even the need for amputation. In response, staged protocols were created. However, recent studies have called this into question, demonstrating low wound complications with early definitive fixation. Additional studies are evaluating adjuvants to minimize wound complications, including the use of vancomycin powder and oxygen supplementation, while another study challenges the 7-cm myth regarding the distance needed between skin incisions. Additional research has been focused on alternative methods of managing these complex, and sometimes non-reconstructable, injuries with the use of external fixation, minimally invasive internal fixation, and primary arthrodesis. Tibial pilon fractures remain difficult to treat for even the most skilled orthopedic trauma surgeons. With improvements in surgical techniques and implants, complication rates have declined and outcomes have improved; however, the overall prognosis for these injuries often remains poor.

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.

Modified posteromedial approach for treatment of posterior pilon variant fracture

Background

Posterior pilon variant fracture is a recently described posterior malleolus fracture characterized by the involvement of both posterolateral and posteromedial malleolar fragment. The associated surgical approach remains controversial. The aim of this study was to present the application of modified posteromedial approach in the treatment for posterior pilon variant fracture.

Methods

Sixteen patients were identified with posterior pilon variant fractures. All fractures were operated via modified posteromedial approach. Fragment length ratio, area ratio and height were measured as morphologic assessments. The clinical outcome was evaluated with American Orthopaedic Foot & Ankle Society ankle-hind foot score and visual analogue scale. Radiological images were evaluated using osteoarthritis-score.

Results

According to the radiological measurements, the average fragment length ratio of posteromedial and posterolateral fragment was 25.3 and 31.5 % respectively. All fractures healed within a mean period of 13.1 weeks without malalignment or articular step-off. Fourteen patients were followed up, and all achieved good or excellent ankle function. The average score of American Orthopaedic Foot & Ankle Society and visual analogue scale at rest, motion and weight bearing walking was 85.6 and 0.25, 0.81, 1.31 respectively.

Conclusion

Modified posteromedial approach provides an alternative surgical treatment for posterior pilon variant fractures, and the short-term outcome was good.

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1182-9) contains supplementary material, which is available to authorized users.

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.