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The Journal of Foot & Ankle Surgery 50 (2011) 413–415

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The Journal of Foot & Ankle Surgery

journal homepage: www.j fas .org

Magnetic Resonance Imaging and Incidental Findings of Lateral AnklePathologic Features with Asymptomatic Ankles

Amol Saxena, DPM, FACFAS 1, Amit Luhadiya, DPM2, Brynn Ewen, DPM2, Chris Goumas, MD3

1 Fellowship Director, Palo Alto Division, Palo Alto Foundation Medical Group, Palo Alto, CA2 Fellow, Palo Alto Division, Palo Alto Foundation Medical Group, Palo Alto, CA3 Staff Radiologist, Palo Alto Division, Palo Alto Foundation Medical Group, Palo Alto, CA

a r t i c l e i n f o

Level of Clinical Evidence: 3Keywords:fibulainstabilityligamentperoneal tendonsurgerytalustibia

Financial Disclosure: None reported.Conflict of Interest: None reported.Address correspondence to: Amol Saxena, DPM

Medicine, Palo Alto Foundation Medical Group, ClarPalo Alto, CA 94301.

E-mail address: heysax@aol.com (A. Saxena).

1067-2516/$ - see front matter � 2011 by the Americdoi:10.1053/j.jfas.2011.03.011

a b s t r a c t

We prospectively evaluated 102 magnetic resonance imaging (MRI) examinations in 100 patients withasymptomatic lateral ankles. The patients were undergoing MRI for other ankle pathologic features, includingmedial ankle, posterior ankle, soft tissue masses, or Achilles tendon pain. No patient had had a recent lateralankle injury or any surgery. Whether the anterior talofibular ligament, calcaneofibular ligament, and peronealtendons were intact, torn, or absent was recorded. The average patient age was 46.4 years. Of the 100 patients,67 (66%) had no history of a lateral ankle sprain, and 35 (34%) had sustained 1 or more sprains in the remotepast. Also, 72 had an intact anterior talofibular ligament (71%), 90 had an intact calcaneofibular ligament (89%),67 had intact peroneus brevis tendons (66%), and 68 (67%) had intact peroneus longus tendons. One accessoryperoneal tendon was noted. Approximately 30% of asymptomatic patients undergoing MRI had abnormalanterior talofibular ligaments and peronei. Because the published data show that functional rehabilitation issuccessful for 90% of symptomatic lateral ankle patients, caution is warranted if choosing surgical treatment onthe basis of the MRI findings alone.

� 2011 by the American College of Foot and Ankle Surgeons. All rights reserved.

Lateral ankle sprains have a high incidence among athletes andare the most common musculoskeletal injury in the United States,with an occurrence of 30,000 daily (1). Nonoperative treatment, suchas bracing and physical therapy, yields good results for most patients(1–16). In chronic cases, magnetic resonance imaging (MRI) could beneeded. Other types of ankle pain due to osteochondral defects,Achilles tendinopathy, ankle impingement, ankle synovitis, peronealtendon and retinacular pathologic features, posterior tibial tendondysfunction, degenerative arthrosis, soft tissue masses, and stressfractures also can require MRI examination (8–12). These injuries canbe evaluated through direct examination, radiographic studies (MRI),and functional assessment, and treatment should not determinedfrom the MRI results alone (1, 2, 8–12, 14, 16). False-positive resultscan occur with MRI, and a certain percentage of patients can haveasymptomatically torn peronei or lateral ankle ligaments andtherefore “normal abnormal” findings (1, 3, 8, 15).

The foot position during the MRI study can change the visualiza-tion of the ankle structures. During the MRI examination, the foot

, FACFAS, Department of Sportsk Building, 795 El Camino Real,

an College of Foot and Ankle Surgeon

must be in the proper position to increase visualization and decreasethe “magic angle” effect (pseudo-appearance of torn structures),otherwise false-positive results can occur. Wang et al. (15) stated thatimaging the foot in mild plantar flexion (approximately 20�) can helpdecrease the magic angle effect because the peroneal tendonsdescend down the ankle and the fibers form an angle of 55� with themain magnetic vector, which, in turn, produces increased signalintensity. Taking these calibrations into account should provide bettervisualization of overlooked lateral ankle diseases concomitant withother foot and ankle pathologic features (i.e., plantar fasciitis, poste-rior tibial tendon dysfunction, Achilles tendonitis, tibialis anteriortendonitis). When evaluating peroneal subluxation, MRI should bedone with the ankle dorsiflexed (12).

Because of the reported incidence of false-positive results whenreviewing MRI studies, we studied the incidence of lateral anklepathologic features visualized in asymptomatic individuals. Wespecifically wanted to exclude any patients with a recent history oflateral ankle trauma or any surgery. We recorded the percentage ofpatients with no lateral ankle pain whatsoever who had intact lateralankle ligaments and tendons on MRI.

Patients and Methods

The patients of 1 practitioner (A.S.) in a sports medicine clinic undergoing MRIexamination of their ankles were prospectively studied for lateral ankle pathologic

s. All rights reserved.

Fig. 1. (A) MRI scan showing intact anterior talofibular ligament. (B) MRI scan showingintact calcaneofibular ligament and peronei.

A. Saxena et al. / The Journal of Foot & Ankle Surgery 50 (2011) 413–415414

findings. The institutional review board approved the present study. The ankles werescanned using a Philips Achieva 3T (Philips, Amsterdam, The Netherlands) with anInvivo 8-channel foot and ankle array (Invivo, Amsterdam, The Netherlands). Thereports were evaluated for the presence, absence, or abnormal findings of the lateralankle ligaments and peroneal tendons. Specifically, the data were recorded if theanterior talofibular ligament, calcaneofibular ligament, and peroneal tendons wereintact, torn, or absent. Incidental findings of accessory ossicles and other lesions werealso recorded. The inclusion criteria were patients undergoing an MRI examinationfrom June 2007 to July 2009 for evaluation of nonlateral ankle pain. These patientstypically complained of medial ankle, posterior ankle, soft tissue masses, or Achillestendon pain. The exclusion criteria were any concurrent lateral ankle pain. Any patientswith an injury in the previous 10 years or any previous lateral ankle surgery were alsoexcluded. We sought to ensure that none of the potential pathologic features found inthe lateral ankle onMRI had resulted from any residual injury. Because of these criteria,253 patents were excluded, underscoring the frequency of lateral ankle sprains in thesports medicine population. A total of 100 patients undergoing 102 MRI examinations(2 bilateral) fulfilled the criteria. Typical examples of normal (Figure 1), asymptomatic“abnormal” (Figure 2), and symptomatic abnormal (Figure 3) MRI scans were collected.

Results

A total of 102MRI examinations from 100 patients were evaluated;52 on the right and 50 on the left ankle (2 patients had bilateral

Fig. 2. (A) MRI scan showing “abnormal” anterior talofibular ligament in asymptomatic patie(C) MRI scan showing “abnormal” split peroneus brevis in asymptomatic patient.

examinations). Of the 100 patients, 50 each were male and females,with an average age of 46.4 years. Twenty-five patients eventuallyunderwent surgery for nonlateral ankle pathologic features. The mostcommon abnormality being evaluated by MRI was Achilles tendin-opathy (N ¼ 40), followed by posterior tibial tendon dysfunction(N ¼ 26). Of the 100 patients (102 examinations), 67 (66%) had nohistory of a lateral ankle sprain and 35 (34%) had sustained 1 or moresprains in the remote past. Of these patients, 72 had an intact anteriortalofibular ligament (71%), 90 had an intact calcaneofibular ligament(89%), 67 (66%) had intact peroneus brevis tendons, and 68 (67%) hadintact peroneus longus tendons. One accessory peroneal tendon wasnoted. Also, 20 accessory ossicles (with os trigonum the mostcommon with 7 occurrences) and 15 osteochondral defects (8 medialand 7 lateral) were noted. One lateral talar lesion necessitated surgeryfor subtalar arthrosis. The MRI study changed the original diagnosis in2 cases.

The practitioner ordering the examinations tallied the number ofankle stabilizations performed for symptomatic ankle instabilityunresponsive to physical therapy and bracing during the same studyperiod. He performed 42 lateral ankle stabilizations, often withconcomitant tendon or chondral repair. This was compared with thenumber of ankle sprains (N¼ 424) treated during the same period, fora 10% surgical repair rate.

Discussion

Our study has shown that approximately 30% or more of patientswith asymptomatic lateral ankles have abnormal anterior talofibularligament ligaments or peroneal tendons. This can be significant ifclinicians rely on MRI reports onwhich to base treatment. If cliniciansor patients rely on the MRI results for treatment, they could be misledand unjustly choose lateral ankle surgery. This needs to be studiedfurthered in patients with lateral ankle pain. The study limitationsinclude that the ankles studied were not truly asymptomatic. Ideally,truly asymptomatic patients with no history of ankle injuries shouldbe studied.

Patients with symptoms from lateral ankle instability can betreated in most cases nonsurgically. In cases inwhich the patient doeshave acute or chronic ankle instability, Schenck and Coughlin (12)stated that ankle instability is a common problem that is routinelytreated nonoperatively, with a 90% success rate. This should be

nt. (B) MRI scan showing “abnormal” calcaneofibular ligament in asymptomatic patient.

Fig. 3. (A) MRI scan showing ruptured (Grade 3) anterior talofibular ligament in patientwith acute lateral ankle sprain. (B) MRI scan showing ruptured calcaneofibular ligamentand peronei in patient with acute lateral ankle sprain.

A. Saxena et al. / The Journal of Foot & Ankle Surgery 50 (2011) 413–415 415

studied prospectively with a larger study and surgeon population. Thefinding reported in the present study of the senior author’s (A.S.)surgical rate in symptomatic patients of 10% is consistent with thepublished data. We did not study whether the remaining 90% ofpatients had undergone surgical treatment elsewhere.

Maffulli and Ferran (9) studied cast immobilization versus func-tional management (rest, ice, compression, elevation [RICE] followedby rehabilitation, i.e., proprioceptive retraining and strengtheningexercises) for the acute ankle sprain. Using randomized controlledtrials, they reported that functional management allowed for earlierresumption of sports training, with fewer symptoms 3 to 6 monthsafter injury (9). Kerkhoffs et al (5, 6) stated that conservative treat-ment leads to a full functional recovery for most people. Richie (11)and others (12, 13, 16) addressed conservative treatment of acute orchronic ankle instability and also showed the benefits of mechanicalsupportive aid to the ankle in the form of taping or bracing.

With respect to lateral ankle ligament pathologic findings insymptomatic patients andMRI, in a retrospective study of 32 patients,Lamm et al. (8) showed that a MRI diagnosis of a peroneus brevistendon tear had a 83% sensitivity and 75% specificity to the intra-operative findings. Coexisting conditions identified on MRI includeda low lying muscle belly/peroneus quartus (44%), anterior talofibularligament rupture (50%), flattened/hypertrophy peroneus longustendon (56%), increased signal intensity within the peroneus longus

tendon (53%), and a flat/convex fibular groove (78%) (8). In our study,we did not assess the fibular groove.

The overall incidence of lateral ankle pathologic findings inasymptomatic individuals is significant. Approximately 30% ofasymptomatic individuals have abnormal anterior talofibular liga-ments and peroneal tendons. Because of the success rate of nonop-erative treatment of lateral ankle sprains and the incidence ofasymptomatic patients, practitioners should use caution whenconsidering surgery for lateral ankle pain according to the MRI find-ings, particularly in this patient population.

References

1. DiGiovanni CW, Brodsky A. Current concepts: lateral ankle instability. Foot AnkleInt 27:854–866, 2006.

2. de Vries JS, Krips R, Sierevelt IN, Blankevoort L, van Dijk CN. Interventions fortreating chronic ankle instability. Cochrane Database System Rev, Issue4:CD004124, 2006.

3. Heckman D, Reddy S, Pedowitz D, Wapner K, Parekh S. Operative treatment forperoneal disorders. J Bone Joint Surg Am 90:404–418, 2008.

4. Karlsson J, Lundin O, Lind K, Styf J. Early mobilization versus immobilization afterankle ligament stabilization. Scand J Med Sci Sports 9:299–303, 1999.

5. Kerkhoffs GMMJ, Handoll HHG, de Bie R, Rowe BH, Strujis PAA. Surgical versusconservative treatment for acute injuries of the lateral ligament complex of theankle in adults. Cochrane Database System Rev, Issue 2:CD000380, 2002.

6. Kerkhoffs GMMJ, Struyss PAA, Marti RK, Assendelft WJJ, Blankevoort L, vanDijk CN. Different functional treatment strategies for acute lateral ankle ligamentinjuries in adults. Cochrane Database System Rev, Issue 3:CD002938, 2002.

7. Klenerman L. The management of sprained ankle. J Bone Joint Surg Br 80:11–12,1998.

8. Lamm BM, Myers DT, Dombek M, Mendicino RW, Catanzariti AR, Saltrick K.Magnetic resonance imaging and surgical correlation of peroneus brevis tears.J Foot Ankle Surg 43:30–36, 2004.

9. Maffulli N, Ferran N. Management of acute and chronic ankle instability. J Am AcadOrthop Surg 16:608–615, 2008.

10. Pijnenburg AC, Bogaard K, Krips R, Marti RK, Bossuyt PM, Van Dijk CN. Operativeand functional treatment of the lateral ligament of the ankle: a randomized,prospective trial. J Bone Joint Surg Br 85:525–530, 2003.

11. Richie DH Jr. Functional Instability of the ankle and the role of neuromuscularcontrol: a comprehensive review. J Foot Ankle Surg 40:240–251, 2001.

12. Schenck R Jr, Coughlin M. Lateral ankle instability and revision surgery alternativesin the athlete. Foot Ankle Clin North Am 14:205–214, 2009.

13. Specchiulli F, Cofano RE. A comparison of surgical and conservative treatment inankle ligament tears. Orthopedics 24:686–688, 2001.

14. Van Dijk CN, Lim LS, Bossuyt PM, Marti RK. Physical examination is sufficient forthe diagnosis of sprained ankles. J Bone Joint Surg Br 78:958–962, 1996.

15. Wang X, Rosenberg Z, Mechlin M, Schweitzer M. Normal variants and diseases ofthe peroneal tendons and superior peroneal retinaculum: MR imaging features.Radiographics 25:587–602, 2005.

16. Zwipp H, Tscherne H, Hoffmann R, Thermann H. Ankle ligament tears: operative orconservative treatment [Rib der knochelbander: operative oder konservativbehandlung?]. Deutsches Arzteblatt 31:B2019–B2022, 1988.