The diagnostic value of MRI in foot and ankle surgery

Ankle MRI and preceding radiographs: an evaluation of physician ordering practices

OBJECTIVE

Multiple guidelines have been published for appropriate imaging in patients with ankle-related symptoms which suggest radiographs as the initial imaging examination for both acute and chronic ankle abnormalities. Few studies have evaluated adherence to these imaging guidelines. This study retrospectively evaluated the utilization of ankle MRI and preceding radiographs based on ordering provider group and MRI indication.

MATERIALS AND METHODS

A total of 4186 ankle MRIs performed over a 9-year period at a single institution were evaluated for the presence of preceding ankle and/or foot radiographs at two time points, within 3 months and within 6 months of the MRI examination. Ankle MRIs were then categorized based on 6 ordering provider groups and 13 MRI indications.

RESULTS

Of the 4186 MRIs evaluated, 68% had preceding radiographs within 3 months and 77% had radiographs within 6 months. Primary care, sports medicine, and podiatry had the lowest rates of preceding radiographs (73%, 68%, and 64%, respectively, within 6 months). Eighty-six percent of ankle MRIs ordered by orthopedic surgery had preceding radiographs within 6 months and 89% of ankle MRIs ordered by emergency medicine and inpatient providers had preceding radiographs. MRIs intended for evaluation of Achilles tendon or plantar fascia abnormalities were among the least likely indications to have preceding radiographs.

CONCLUSION

Based on established clinical guidelines, there was a lower-than-expected rate of obtaining preceding radiographs for ankle MRIs among most provider groups, particularly non-orthopedic outpatient providers. Additional research is needed to address the lack of adherence to clinical imaging guidelines and ensure appropriate imaging.

Magnetic Resonance Accuracy in the Diagnosis of Anterior Talo-Fibular Ligament Acute Injury: A Systematic Review and Meta-Analysis

BACKGROUND

The studies about injury to the anterior talo-fibular ligament (ATFL) are focused mainly on chronic symptoms and chronic instability, and the literature about the accuracy of magnetic resonance imaging (MRI) in acute injuries is quite lacking.

METHODS

This systematic review with meta-analysis analyzes the diagnostic accuracy of MRI on acute ATFL injury. Relative studies were retrieved after searching three databases (MEDLINE, SCOPUS, and Cochrane Central Register of Controlled Trails). Eligible studies were summarized. The quality of the included articles was assessed using the revised Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool. Data were extracted to calculate pooled sensitivity and specificity of MRI.

RESULTS

Seven studies met our inclusion and exclusion criteria. For MRI, the pooled sensitivities and specificity in diagnosing acute ATFL injury were respectively 1.0 (95% CI: 0.58-1) and 0.9 (95% CI: 0.79-0.96). Pooled LR+ and LR- were respectively 10.4 (95% CI: 4.6-23) and 0 (95% CI: 0-0.82).

CONCLUSION

This systematic review with meta-analysis investigated the accuracy of imaging for the diagnosis of acute ATFL injury. Our results demonstrated that MRI shows high diagnostic accuracy in the diagnosis of acute ATFL lesions. These results suggest that routine MRI in the case of suspected ATFL acute injury may be clinically useful, although this is not done in clinical practice due probably to high cost.

Flexor hallucis longus hypertrophy secondary to Achilles tendon tendinopathy: an MRI-based case-control study

PURPOSE

The purpose of this study was to outline an indirect sign of advanced Achilles tendinopathy on magnetic resonance imaging (MRI), based on the hypothesis that these patients would present with secondary hypertrophy of the flexor hallucis longus muscle (FHL).

METHODS

MRI scans of Achilles tendon were analyzed retrospectively in two cohorts. The study group consisted of consecutive patients presenting with clinical signs of Achilles tendinopathy and no previous surgeries, while the control group were patients that had an MRI due to other reasons and no signs of tendinopathy. Two parameters from two muscle bellies were measured and compared on axial MRI scans 4-5 cm above the ankle joint line at the level of greatest thickness: area and diameter of the triceps surae (TS) and of the FHL muscle. Ratios (FHL/TS) were calculated for area (Ar) and diameter (Dm) measurements. Interobserver agreement was analyzed. A receiver operating characteristic (ROC) curve was created for both ratios to assess potential cutoff points to differentiate between the groups.

RESULTS

A total of 60 patients for each study group were included. Both ratios Ar(FHL/TS) and Dm(FHL/TS) showed significant higher values in the tendinopathy group (p < 0.001). There were strong to very strong intraclass correlation coefficients (ICC = 0.75-0.93). A diameter ratio Dm (FHL/TS) of 2.0 or higher had a sensitivity of 49% and specificity of 90% for concomitant Achilles tendinopathy.

CONCLUSION

In our patient cohort, FHL hypertrophy was observed in patients with Achilles tendinopathy as a possible compensatory mechanism. Measuring a diameter ratio Dm(FHL/TS) of 2.0 or higher on an axial MRI, may be indicative as an indirect sign of functional deterioration of the Achilles tendon.

Relevance of SPECT-CT in Complex Cases of Foot and Ankle Surgery: A Comparison With MRI

BACKGROUND

Finding the right diagnoses in patients with complex foot and ankle disorders can be challenging. Single-photon emission computed tomography and computed tomography (SPECT-CT) has shown to be feasible in foot and ankle surgery. The aim of this study was to evaluate the reliability and accuracy of SPECT-CT and thereby its impact on final treatment decision compared with magnetic resonance imaging (MRI).

METHODS

A retrospective study was performed on 49 patients treated at our institution. Experienced foot and ankle surgeons independently, and blinded, analyzed clinical data and radiographs together with MRI, SPECT-CT, or a combination of both. Based on the determined final treatment decision Cohen's kappa values were calculated to illustrate interrater and intrarater reliability.

RESULTS

The kappa values for interrater reliability were higher for SPECT-CT at .68 and MRI + SPECT-CT at .71 compared to 0.38 for MRI alone (P < .05). The kappa values for intrarater reliability of MRI + SPECT-CT were higher at .75 compared with SPECT-CT alone at .67 (P < .05) and MRI at .35 (P < .01).

CONCLUSION

We found a higher interrater and intrarater reliability for SPECT-CT compared with MRI alone for diagnosing complex foot and ankle pathologies. SPECT-CT has a high impact on final treatment decision. The main indications are bony pathologies with diagnostic uncertainty especially in closely adjacent structures as the joints of the midfoot, occult coalitio, stress fractures, verification or exclusion of nonfusion, periprosthetic disorders after total ankle replacement and osteochondral lesion in cases of combined pathologies.Levels of Evidence: Level IV: Retrospective study.

Approaching Foot and Ankle Injuries in the Ambulatory Setting

Foot and ankle injuries account for a significant volume of primary care office visits each year. Given the incidence of injury and concern for long-term sequelae, it is imperative that primary care physicians familiarize themselves with commonly encountered foot and ankle injuries. Coupling a sound understanding of key anatomic structures with an appropriately gathered history can help to quickly narrow the differential diagnosis in this clinical presentation. This article focuses on key elements from the history and physical examination as well as provides a concise review of imaging modalities and recommended treatment strategies.

Methods to detect inappropriate use of MRI and CT for musculoskeletal conditions: A scoping review

OBJECTIVE

Identify and evaluate methods suitable for detecting inappropriate use of MRI or CT in the musculoskeletal system.

DESIGN

Systematic review of studies that described methods to measure inappropriate use of MRI or CT in the musculoskeletal system. We used a multi-step strategy to classify identified methods into categories. These categories were then analyzed according to the data needed and their limitations.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

English or German language studies that measured inappropriate use of MRI or CT in the musculoskeletal system. Articles were also included if they reported a general approach to the measurement of inappropriate imaging regardless of body region. Expert opinions, unsystematic reviews, commentaries, articles without abstracts, and studies on cancer were excluded.

RESULTS

47 studies met the inclusion criteria. The categorization of the studies resulted in seven individual approaches to measure inappropriate use: (1) availability of meaningful diagnostic information; (2) predictors associated with imaging use; (3) comparison with guideline recommendations; (4) assessment by experts; (5) comparison or analysis of patients' paths; (6) comparison with surgery findings; (7) geographic variation. All these approaches have specific data requirements and individual advantages and disadvantages regarding risk of bias and needed data.

CONCLUSIONS

We could not find a single method of choice to detect inappropriate use of MRI or CT in the musculoskeletal system. A combination of different approaches is the preferred strategy to deal with the advantages and disadvantages of the individual methods.

Appropriateness of the Use of Magnetic Resonance Imaging in the Diagnosis and Treatment of Wrist Soft Tissue Injury

BACKGROUND

When diagnosing wrist soft tissue injury, the authors hypothesize that magnetic resonance imaging is used injudiciously and is associated with unnecessary cost.

METHODS

A retrospective review was conducted of patients aged 20 to 60 years who underwent magnetic resonance imaging for possible wrist soft tissue injury at a tertiary care center between 2009 and 2014. Treatment recommendation was classified as nonoperative, operative, or equivocal. If the magnetic resonance imaging-directed treatment recommendation differed from the pre-imaging recommendation, it was noted that the imaging influenced patient care (impact study). The cost estimate of an impact study was calculated by dividing the total studies performed by the number of studies that impacted the treatment recommendation and multiplying this value by the institutional wrist magnetic resonance imaging cost ($2246 in 2016).

RESULTS

One hundred forty patients were included. Magnetic resonance imaging affected treatment recommendation in 28 percent of patients. Independent predictors of impact on treatment recommendation were "question specific injury" (OR, 9.46; 95 percent CI, 3.18 to 28.16; p < 0.001) and "question scapholunate injury" (OR, 2.88; 95 percent CI, 1.21 to 6.88; p = 0.02). The only independent predictor of surgery was ordering physician (hand surgeon) (OR, 3.69; 95 percent CI, 1.34 to 10.13; p = 0.01). The cost of an impact study ordered by a non-hand surgeon versus a hand surgeon was $13,359 versus $6491, respectively.

CONCLUSIONS

The provider must carefully consider the pretest probability of ordering a study that will affect treatment recommendation. Injudicious screening with magnetic resonance imaging ($15,565) incurred a cost nearly seven times the cost of the one imaging scan ($2246) before impacting one treatment recommendation. In the current era of cost containment and bundled payment, diagnostic test probability must be appreciated to guide physician ordering practices.

Accuracy of magnetic resonance imaging in diagnosing lateral ankle ligament injuries: A comparative study with surgical findings and timings of scans

Objective

This study aimed to evaluate the accuracy of magnetic resonance imaging (MRI) in diagnosing lateral ankle ligament injuries and the effect of differences in time duration from injury to MRI.

Methods

Data were collected prospectively from 82 patients who underwent MRI and lateral ligament reconstruction, and were divided into either acute (≤3 months) or chronic (>3 months) group based on injury interval. Findings were classified as normal, partial, or complete tears of the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL). MRI results were compared with intraoperative findings and their accuracies were assessed using descriptive statistics.

Results

The accuracy of MRI for partial and complete tears of the ATFL was 74% and 79%, respectively, with sensitivity and specificity of 64% and 86% for partial tears, and 78% and 80% for complete tears, respectively. The accuracy of MRI was 66% and 88% for partial and complete tears of the CFL with a sensitivity and specificity of 41% and 87% for partial tears, and 61% and 95% for complete tears, respectively. A decrease in the MRI accuracy was observed in the chronic group.

Conclusion

MRI is accurate in diagnosing ATFL injuries. It is specific but not sensitive for CFL tears. The accuracy is higher in the acute setting of 3 months or less from time of injury to MRI.

Validation of a novel ultrasound measurement of achilles tendon length

PURPOSE

A clinically applicable and accurate method for measuring Achilles tendon length is needed to investigate the influence of elongation of the Achilles tendon after acute rupture. The purpose of this study was to develop and validate an ultrasonographic (US) length measurement of the Achilles tendon-aponeurosis complex.

METHODS

Both legs of 19 non-injured subjects were examined by magnetic resonance imaging (MRI) and US. The length from calcaneus to the medial head of m. Gastrocnemius was measured by three independent US examiners. Repeated US measurements were performed and compared to MRI measurements. Intra-rater and inter-rater reliability and the agreement between MRI and US were determined. Data were evaluated using the intraclass correlation coefficient (ICC), the standard error of the measurement (SEM) and the minimal detectable change (MDC).

RESULTS

Intra-rater reliability of US assessment showed no significant differences between test days: ICC 0.96, SEM 4 mm and MDC 10 mm. Inter-rater reliability showed a systematic difference between US observers of 2-5 mm (p = 0.001-0.036); ICC 0.97, SEM 3 mm and MDC 9 mm. MRI measurements were on average 4 mm longer than US (p = 0.001).

CONCLUSION

The novel ultrasound measurement showed good reliability and accuracy. For comparison between groups of non-injured subjects differences of more than 4 mm can be detected. For repeated assessment of individual subjects differences of more than 10 mm can be detected. The measurement needs to be further assessed in the setting of acute Achilles tendon rupture.

CLINICAL RELEVANCE

This new ultrasound measurement might allow for length measurement of ruptured Achilles tendons in the acute and chronic state after rupture.

LEVEL OF EVIDENCE

II.

MRI is unnecessary for diagnosing acute Achilles tendon ruptures: clinical diagnostic criteria

BACKGROUND

Achilles tendon ruptures are common in middle-aged athletes. Diagnosis is based on clinical examination or imaging. Although MRI is commonly used to document ruptures, there is no literature supporting its routine use and we wondered whether it was necessary.

QUESTIONS/PURPOSES

We (1) determined the sensitivity of physical examination in diagnosing acute Achilles ruptures, (2) compared the sensitivity of physical examination with that of MRI, and (3) assessed care delays and impact attributable to MRI.

METHODS

We retrospectively compared 66 patients with surgically confirmed acute Achilles ruptures and preoperative MRI with a control group of 66 patients without preoperative MRI. Clinical diagnostic criteria were an abnormal Thompson test, decreased resting tension, and palpable defect. Time to diagnosis and surgical procedures were compared with those of the control group.

RESULTS

All patients had all three clinical findings preoperatively and complete ruptures intraoperatively (sensitivity of 100%). MR images were read as complete tears in 60, partial in four, and inconclusive in two patients. It took a mean of 5.1 days to obtain MRI after the injury, 8.8 days for initial evaluation, and 12.4 days for surgical intervention. In the control group, initial evaluation occurred at 2.5 days and surgical intervention at 5.6 days after injury. Nineteen patients in the MRI group had additional procedures whereas none of the control group patients had additional procedures.

CONCLUSIONS

Physical examination findings were more sensitive than MRI. MRI is time consuming, expensive, and can lead to treatment delays. Clinicians should rely on the history and physical examination for accurate diagnosis and reserve MRI for ambiguous presentations and subacute or chronic injuries for preoperative planning.

LEVEL OF EVIDENCE

Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Magnetic resonance imaging in evaluating workers' compensation patients

PURPOSE

We studied the utility of magnetic resonance imaging (MRI) studies for workers' compensation patients with hand conditions in which the referring doctor obtained the images. We compared the MRI findings with the eventual clinical findings. We also investigated the approximate cost of these MRI studies.

METHODS

We retrospectively reviewed the charts of all workers' compensation patients seen in a hand and upper extremity practice over the course of 3 years. We selected patients who had MRI studies of the affected upper extremities before referral to the senior author (G.R.). We reviewed the charts for information regarding demographics, referral diagnoses, MRI diagnoses made by the radiologist, the area of the upper extremity studied, and eventual clinical diagnoses by the senior author. We made a determination as to whether a hand surgeon could have adequately diagnosed and treated the patients' conditions without the imaging studies. We also investigated the cost associated with these MRIs.

RESULTS

We included 62 patients with a total of 67 MRI scans in this study. The MRI studies did not contribute to clinically diagnosing the patients' conditions in any of the cases we reviewed. The hand surgeon's clinical diagnosis disagreed with the radiologist's MRI diagnosis in 63% of patients. The MRI was unnecessary to arrive at the clinical diagnosis and did not influence the treatment offered for any of the 62 patients. The total cost for the 67 non-contrast MRI studies was approximately $53,000.

CONCLUSIONS

Costly imaging studies are frequently done to determine the validity of a patient's reported problems; unfortunately, these tests are frequently unnecessary and waste resources. Magnetic resonance imaging scans may not be the standard for accurate diagnosis and can misdirect care.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic III.