The Diagnostic Accuracy of Radiographs and Magnetic Resonance Imaging in Predicting Deltoid Ligament Ruptures in Ankle Fractures

BACKGROUND

Operative indications for supination-external rotation (SER) ankle fractures depend on the integrity of the medial structures. Despite the importance of assessing deep deltoid ligament injuries, the accuracy of common diagnostic tests has not been established.

QUESTIONS/PURPOSES

The objective of this study was to compare the ability of injury (non-stress) and stress radiographs and magnetic resonance imaging (MRI) to diagnose deep deltoid ligament ruptures in operative SER ankle fractures.

METHODS

Patients were included who underwent surgical fixation of SER ankle fractures and had appropriate injury and manual stress test radiographs, pre-operative ankle MRI, and intra-operative assessment of deep deltoid integrity by direct visualization. The medial clear space (MCS) was considered positive for all values over 5 mm on the injury or stress mortise radiographs. MRI analysis of the deep deltoid ligament injury was performed by blinded fellowship-trained musculoskeletal radiologists. Intra-operative direct visualization and assessment of the deltoid was performed using a direct medial ankle approach at the time of operative fracture fixation.

RESULTS

Using intra-operative visualization as the gold standard, MCS measurements and MRI had differing abilities to diagnose a deep deltoid rupture. In cases where the MCS was less than 5 mm on injury radiographs and stress tests were performed, MCS measurements were much less accurate than MRI in predicting deltoid ruptures (46% versus 79%, respectively) with a high false positive rate (80%). In contrast, an MCS measurement of greater than 5 mm on injury radiographs was a strong predictor of deep deltoid rupture (accuracy of 95%).

CONCLUSION

Compared with direct visualization of the deltoid ligament intra-operatively, these data support proceeding with surgery when the MCS on injury radiographs is greater than 5 mm without any additional stress tests or advanced imaging. When the MCS is less than 5 mm, we recommend MRI analysis because of its increased accuracy and decreased false positive rate. Improving our ability to diagnose deltoid ruptures will contribute to more effective management of patients with SER ankle fractures.

Posterior reversible encephalopathy syndrome: temporary visual loss after spinal deformity surgery

Posterior reversible encephalopathy syndrome (PRES) is a rare cause of temporary postoperative visual loss (POVL) after spinal deformity surgery. We report on 2 patients diagnosed with PRES after spinal deformity surgery, who were closely examined postoperatively. A 78-year-old woman with severe disability due to degenerative lumbar spondylosis after laminectomy was treated with transpsoas lumbar interbody fusion from L1 to L4 and posterior spinal fusion from T10 to pelvis. She developed confusion and bilateral visual loss on postoperative day 7. A second patient, a 51-year-old woman with progressive pain and decompensation caused by adult scoliosis, was treated with posterior spinal fusion from T3 to pelvis and interbody fusion from L4 to S1 via a presacral interbody fusion approach. She developed bilateral visual loss on postoperative day 15. Both patients achieved a complete recovery of their vision after medical management of PRES. Timely diagnosis of PRES and prompt intervention allow for a good patient prognosis and complete recovery of eyesight.

MRI safety: a report of current practice and advancements in patient preparation and screening

MRI offers detailed diagnostic images without ionizing radiation; however, there are considerable safety concerns associated with high electromagnetic field strength. With increasing use of high and ultra high (7T) magnetic field strength, adequate patient preparation and screening for ferrous material is increasingly important. We review current safety standards for patient screening and preparation and how they are implemented at our institution. In addition, we describe a novel supplemental screening technique wherein the lights are dimmed in response to detected ferrous metal at the threshold of Zone IV.

Analysis of PITFL injuries in rotationally unstable ankle fractures

BACKGROUND

Reduction and stabilization of the syndesmosis in unstable ankle fractures is important for ankle mortise congruity and restoration of normal tibiotalar contact forces. Of the syndesmotic ligaments, the posterior inferior tibiofibular ligament (PITFL) provides the most strength for maintaining syndesmotic stability, and previous work has demonstrated the significance of restoring PITFL function when it remains attached to a posterior malleolus fracture fragment. However, little is known regarding the nature of a PITFL injury in the absence of a posterior malleolus fracture. The goal of this study was to describe the PITFL injury pattern based on magnetic resonance imaging (MRI) and intraoperative observation.

METHODS

A prospective database of all operatively treated ankle fractures by a single surgeon was used to identify all supination-external rotation (SER) types III and IV ankle fracture patients with complete preoperative orthogonal ankle radiographs and MRI. All patients with a posterior malleolus fracture were excluded. Using a combination of preoperative imaging and intraoperative findings, we analyzed the nature of injuries to the PITFL. In total, 185 SER III and IV operatively treated ankle fractures with complete imaging were initially identified.

RESULTS

Analysis of the preoperative imaging and operative reports revealed 34% (63/185) had a posterior malleolus fracture and were excluded. From the remaining 122 ankle fractures, the PITFL was delaminated from the posterior malleolus in 97% (119/122) of cases. A smaller proportion (3%; 3/122) had an intrasubstance PITFL rupture.

CONCLUSIONS

Accurate and stable syndesmotic reduction is a significant component of restoring the ankle mortise after unstable ankle fractures. In our large cohort of rotationally unstable ankle fractures without posterior malleolus fractures, we found that most PITFL injuries occur as a delamination off the posterior malleolus. This predictable PITFL injury pattern may be used to guide new methods for stabilizing the syndesmosis in these patients.

LEVEL OF EVIDENCE

Level IV, case series.

Ankle fracture spur sign is pathognomonic for a variant ankle fracture

BACKGROUND

The hyperplantarflexion variant ankle fracture is composed of a posterior tibial lip fracture with posterolateral and posteromedial fracture fragments separated by a vertical fracture line. This infrequently reported injury pattern often includes an associated "spur sign" or double cortical density at the inferomedial tibial metaphysis. The objective of this study was to quantitatively establish the association of the ankle fracture spur sign with the hyperplantarflexion variant ankle fracture.

METHODS

Our clinical database of operative ankle fractures was retrospectively reviewed for the incidence of hyperplantarflexion variant and nonvariant ankle fractures as determined by assessment of injury radiographs, preoperative advanced imaging, and intraoperative observation. Injury radiographs were then evaluated for the presence of the spur sign, and association between the spur sign and variant fractures was analyzed.

RESULTS

The incidence of the hyperplantarflexion variant fracture among all ankle fractures was 6.7% (43/640). The spur sign was present in 79% (34/43) of variant fractures and absent in all nonvariant fractures, conferring a specificity of 100% in identifying variant fractures. Positive predictive value and negative predictive value were 100% and 99%, respectively.

CONCLUSION

The ankle fracture spur sign was pathognomonic for the hyperplantarflexion variant ankle fracture. It is important to identify variant fractures preoperatively as patient positioning, operative approach, and fixation construct of variant fractures often differ from those employed for osteosynthesis of nonvariant fractures. Identification of the spur sign should prompt acquisition of advanced imaging to formulate an appropriate operative plan to address the variant fracture pattern.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Benign osseous and articular abnormalities of the pelvis: a review of CT imaging findings

Computed tomography (CT) has become the standard of care for evaluation and follow-up for a wide range of abdominal and pelvic pathology. Many incidental osseous and articular abnormalities of the pelvis are detected on these studies, most of which have a benign etiology. However, most of these studies are interpreted by nonmusculoskeletal radiologists, who may not be familiar with the CT appearances of these benign musculoskeletal abnormalities. Uncertainty often leads to mischaracterization or unnecessary follow-up, resulting in increased health care costs and patient anxiety. This article reviews the CT appearance of the benign musculoskeletal entities that occur in pelvis.

Interventional therapy for carotid artery disease using angioplasty and stenting with embolic protection

Carotid artery angioplasty with stenting (CAS) has emerged as a viable alternative to endarterectomy for the treatment of occlusive vascular disease. Advances in endovascular techniques and the improvement of specialized stents have served to rapidly close the gap with the traditional gold standard surgery. Furthermore, the development of cerebral embolic protection devices has reduced the occurrence of distal embolization of atheromatous material during such interventions and has reduced periprocedural stroke rates considerably. Continued improvements in distal embolic protection have further improved the risk profile of CAS, and increased operator experience with these interventional procedures has also been shown to reduce periprocedural complication rates. Outcomes may continue to improve as more providers gain experience with the evolving endovascular device technology, and several prospective clinical trials are currently investigating the efficacy of CAS with embolization protection versus endarterectomy in different cohorts. This review will survey the background and current literature covering angioplasty and stenting for occlusive disease in the carotid arteries and discuss the current methods employed to prevent distal emboli during intervention.

Metabolism and distribution of [2,3-(14)C]acrolein in lactating goats

The metabolism and distribution of [2,3-(14)C]acrolein were studied in a lactating goat orally administered 0.82 mg/kg of body weight/day for 5 days. Milk, urine, feces, and expired air were collected. The goat was killed 12 h after the last dose, and edible tissues were collected. The nature of the radioactive residues was determined in milk and tissues. All of the identified metabolites were the result of the incorporation of acrolein into the normal, natural products of intermediary metabolism. There was evidence that the three-carbon unit of acrolein was incorporated intact into glucose, and subsequently lactose, and into glycerol. In the case of other natural products, the incorporation of radioactivity appeared to result from the metabolism of acrolein to smaller molecules followed by incorporation of these metabolites into the normal biosynthetic pathways.

Metabolism and distribution of [2,3-(14)C]acrolein in laying hens

The metabolism and distribution of [2,3-(14)C]-acrolein were studied in 10 laying hens orally administered 1.09 mg/kg of body weight/day for 5 days. Eggs, excreta, and expired air were collected. The hens were killed 12-14 h after the last dose and edible tissues collected. The nature of radioactive residues was determined in tissues and eggs. All of the identified metabolites were the result of the incorporation of acrolein-derived radioactivity into normal natural products of intermediary metabolism in the hen except for 1,3-propanediol, which is a known degradation product of glycerol in bacteria.