573050
research-article2015
FAIXXX10.1177/1071100715573050Foot & Ankle InternationalMason et al
Article
Single-Photon-Emission Computed Tomography in Painful Total Ankle Replacements
Foot & Ankle International® 2015, Vol. 36(6) 635–640 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100715573050 fai.sagepub.com
Lyndon W. Mason, MB BCh, MRCS (Eng), FRCS (Tr&Orth)1, James Wyatt, MB ChB1, Clifford Butcher, MB ChB, FRCS (Ed), FRCS (Tr&Orth)1, Hülya Wieshmann, MRCP, FRCR1, and Andrew P. Molloy, MB ChB, MRCS (Ed), FRCS (Tr&Orth)1
Abstract Background: The use of single-photon-emission computed tomography (SPECT) in identifying unexplained pain in the foot and ankle has been described, where other imaging modalities have failed. The investigation of a painful total ankle replacement (TAR) is difficult, often not delineating a definitive cause. Our aim in this study was to investigate the use of SPECT-CT imaging in painful TARs. Methods: We performed a retrospective analysis of SPECT imaging performed for painful TARs in our department between October 2010 and December 2014. There were 14 patients identified who had undergone SPECT-CT imaging for a painful TAR. The mean age was 63.1 years, with a male/female sex ratio of 2:3 and a minimum time from surgery to imaging of 18 months. Results: Of the 14 patients, 13 were positive for increased osteoblastic activity in relation to the periprosthetic area consistent with implant loosening. The most common finding was tracer activity in relation to the talar component in 13 cases. There was additional tracer activity localized to the tibial component in 5 of these cases. In 10 of the 13 cases with prosthetic loosening/failure of bony ongrowth, there was no evidence of loosening on the plain radiographs. Infection was ruled out by using joint aspiration as clinically indicated. Conclusion: In our series, SPECT-CT imaging revealed a high incidence of medial sided talar prosthesis activity consistent with loosening. The finding of a high incidence of talar nonintegration illustrates the limitations of conventional radiology in follow-up of total ankle replacements, as this was not apparent on plain radiographs. We therefore conclude that there should be a high index of suspicion for talar prosthesis nonintegration in patients with otherwise unexplained ongoing medial pain in total ankle replacements. Level of Evidence: Level IV, retrospective case series. Keywords: SPECT, total ankle replacement, failure, aseptic loosening, talar loosening, medial pain The combination of conventional anatomical and functional imaging (hybrid imaging) has proven its value in recent years. The use of 18-Fluorine-FDG positron emission tomography (PET CT) imaging in oncology imaging has shown to have both higher sensitivity and specificity than conventional radiology in the identification of metastasis.31 The increasing use and development of hybrid imaging in musculoskeletal medicine has resulted from the developing success in other medical specialties. In 2005, Groves et al9 described the technique of coregistering bone single-photon-emission computed tomography (SPECT) images of the wrist with multislice CT images using computer software. Since the technique’s presentation, hybrid scanners where SPECT and CT are combined in a single system (SPECT-CT)
have been introduced to the market. The use of SPECT-CT has been advocated in foot and ankle surgery in the assessment of osteoarthritis, postarthrodesis pain, biological activity of talar osteochondral defect, tendinopathies, stress fractures, hindfoot deformity, and coalitions.2,18,22,23,25,34 SPECT-CT imaging has even been used to identify the source of obscure foot and ankle pain.34
1
University Hospital Aintree, Liverpool, UK
Corresponding Author: Lyndon W. Mason, MB BCh, MRCS (Eng), FRCS (Tr&Orth), University Hospital Aintree, Lower Lane, Liverpool, L9 7AL, UK. Email: [email protected]
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The investigation of a painful total ankle replacement (TAR) is difficult, often not defining a conclusive cause. The most common explanations for persistent pain following a TAR include impingement, infection, aseptic loosening, instability, fracture, malposition of the prosthetic components, arthrofibrosis, and cyst formation. Delineating between these causes is difficult, and even with keen clinical acumen and the use of numerous investigations the cause can remain elusive. Recommended investigations of a painful TAR include blood inflammatory markers (ESR, CRP), linear measurements on serial radiological examinations (angular measurement change of 5 degrees, subsidence of talar component on lateral radiograph of 5 mm, radiolucent lines greater than 2 mm or a progressive increase in radiolucency can suggest loosening), and CT.4,5,20 Hintermann et al12 described the use of SPECT-CT as a routine investigation in their workup of a failed TAR. Although a number of authors have alluded to the use of SPECT-CT in identifying loosening or subsidence in TAR, no study has specifically investigated SPECT-CT use in the investigation of painful TAR.1,25 SPECT-CT use in the investigation of painful total knee replacements is more prevalent in the literature, however the natural history and intensity of tracer uptake in relation to different components is relatively unknown with no published studies including control groups.13-16 The tracer uptake identified on SPECT-CT is the result of an increased blood flow and presentation of radiotracer resulting in an increased deposition in any pathology causing hyperemia. This in turn increases the delivery of radiopharmaceuticals to the bone’s osteoblasts. The visually evident increased tracer activity on bone imaging can be due to a number of causes including physiological bone repair as a result of trauma or failure of ongrowth, hypersensitivity reaction to prosthesis material with subsequent loosening, malignancy, infection, and foreign body reaction to implants. The primary purpose of this study was to evaluate the clinical value of SPECT/CT in patients with ongoing pain following TAR. The hypothesis was that the use of SPECT/ CT would have substantial clinical importance in terms of establishment of a diagnosis in patients with ongoing pain following TAR.
Methods We completed a retrospective analysis of SPECT-CT imaging (SPECT-CT imaging performed by Symbia T2; Siemens, Munich, Germany), used for investigation of painful TARs in our department. The study was performed between October 2010 and December 2014, from the date we gained access to SPECT-CT within our department. Patients who underwent TAR in our unit would be routinely seen in our outpatient department at 2 weeks, 6 weeks, 3 months, 6 months, and 12 months postsurgery. They would
then be routinely followed yearly. Serial weight-bearing anteroposterior, lateral weight-bearing radiographs and Saltzman alignment views were taken at 6 weeks, 3 months, 6 months, and yearly.28 Unremitting pain after 12 months postsurgery was investigated initially with inflammatory markers (full blood count, C-reactive protein, and erythrocyte sedimentation rate) and plain radiographs. SPECT-CT imaging was requested in all cases where the pain continued over 1 year postsurgery. Any suspicion of infection clinically and/or through investigation prompted joint aspiration and microbiological culture. There were 14 patients identified who had undergone SPECT-CT imaging for a painful TAR. The mean age was 63.1 years (range 34-78), with a male to female sex ratio of 2:3. The minimum time from indicative surgery to undergoing SPECT-CT imaging was 18 months. The implants used in this cohort included 11 Mobility® TARs and 3 Buechel-Pappas TARs. For this study, clinical information was gathered from the patient’s documentation and all other relevant imaging was reviewed for the presented cases. The routine nuclear medicine imaging protocol includes spot planar views and SPECT-CT of the lower limbs at 2-hours after the injection of 740 MBq 99mTechnetium labeled Methylene Diphosphonate (99mTc MDP). During the time period covered in this study and the prestudy lead-up to the use of SPECT-CT within our department, there were 66 TARs performed by our 2 senior authors. Both senior authors were fellowship-trained foot and ankle surgeons who performed TAR as part of their routine clinical practice. A mixture of the Mobility total ankle arthroplasty system (DePuy International Ltd, Leeds, UK) and its predecessor the Buechel-Pappas® TAR (Wright Cremascoli Orthopaedics, Europe) were used during this period, dictated by surgeon preference and clinical need. Neither of these devices are currently FDA approved.
Results Of the 14 patients, 13 were positive for increased osteoblastic activity in relation to the periprosthetic area. The abnormal tracer activity in our cohort most commonly localized to the talar component, with 12 cases. The medial aspect of the implant was more commonly afflicted. In 4 of these cases there was abnormal tracer activity around the tibial component also. In 1 case with talar component tracer activity, tracer also localized to the subtalar joint, in keeping with arthropathy. There was 1 case of isolated tibial component activity. There was 1 case negative for osteoblastic activity and infection, where no source for the pain was found. All cases underwent weight-bearing anteroposterior and lateral radiographs of the ankle joint and Saltzman alignment views. Of these, 10 cases showed no evidence of abnormality either osseous or implant related (Figures 1a-b). The remaining 4 cases, showed some abnormality. In 1 case, there was subtalar osteoarthritic change, which corresponded
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Figure 1. Postoperative weight-bearing anteroposterior and lateral radiographs of a painful Mobility total ankle replacement, 4 years following implantation. There is satisfactory alignment and no obvious loosening of the implants.
to that found on SPECT-CT. This was combined with tibial component malalignment although there was no tracer activity in relation to the tibial component, however the talar component had increased activity. One case showed loosening of the tibial component, and this correlated with the SPECT-CT findings, however again the talar component SPECT-CT activity was not demonstrated on plain radiography. There were 2 cases that exhibited talar component lucency, 1 of which with cystic change, both corresponding to the SPECT-CT findings. In all cases, there was no clinical evidence to indicate infection. As part of the routine investigation of a painful prosthesis, inflammatory markers were obtained, but did not show any abnormality in any case. Two cases underwent joint aspiration and microbiology culture, which yielded no microbiological growth. The results of the SPECT-CT imaging, was instrumental in further treatment of this patient cohort. Following the results, 5 patients underwent revision of the ankle replacement to another replacement, 3 underwent conversion of TAR to fusion, 1 patient underwent subtalar fusion, and 4 patients following discussion decided to remain under review. Of the 8 TARs that underwent operative intervention, all displayed poor bony ongrowth in relation to the area indicated with SPECT-CT imaging (Figures 2, 3). Intraoperative sampling at the time of the operation showed no evidence of infection.
Discussion Zaidi36 performed a meta-analysis of TAR outcomes, which included 58 articles with 7942 TARs. They found that the
AOFAS and visual analogue scale scores for pain showed statistically significant improvements 10 years postoperatively. Pain relief, however, is not always complete, with between 24 and 75% reporting no pain at latest followup.1,6,11,17,19,29,32,33 Significant ongoing pain following TAR has been reported in up to 60% of cases.8 In our study, a total of 14 TARs from 66 implanted (21%) experienced significant ongoing pain in relation to the ankle requiring further investigation. Specifically, ongoing medial-sided pain has been associated with the Mobility implant and its predecessor the Buechel-Pappas TAR, with Muir et al24 reporting 14% (18 of 129) of ongoing pain at 4 years with the Mobility, and Kurup and Taylor21 reported 23.5% (8 of 34) medial associated pain with the Buechel-Pappas implant.21,24,27,35 Medial pain is not limited to these implants however, with Rippstein26 reporting occurrence in the Scandinavian Total Ankle Replacement (STAR®) stating that the cause of persistent pain was contact of the talar component with the malleoli. Kim et al17 reported an incidence of medial pain in 47.3% (of 120 ankles) when using the Hintegra system. Barg et al3 classified the etiology of the medial pain in TARs into either impingement/contracture of the medial ligaments or varus/ valgus malalignment. They stated however, that implant failure should not be underestimated. Kurup and Taylor21 implicated medial impingement and ongoing gutter arthritis as the cause of the medial pain, and reported success in 2 cases where debridement was undertaken. Kim et al17 also described success in 7 patients who underwent arthroscopic medial gutter debridement who had ongoing medial sided
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Figure 2. SPECT-CT showing talar component tracer activity.
Figure 3. Explanted Mobility talar component of the same patient with only a small bony island of ongrowth visible.
ankle pain. In our series, SPECT-CT imaging revealed a high incidence of medial sided talar prosthesis loosening. This finding was not apparent on plain radiographs, and we suspect this cause for ongoing medial sided pain has been underreported. Zaidi et al36 found that radiological outcomes were reported in 26 articles (3045 ankles). At a mean follow-up of 4.4 years, radiolucencies were reported adjacent to a mean of 21% of the tibial and 1.4% of the talar components. This meta-analysis also found that the best reported results to be by surgeon designers, who reported a mean annual failure rate (AFR) of 1.1%.36 In contrast, published
literature from non-surgeon-designers reported a mean AFR of 1.7%, and national joint registries reported a mean AFR of 3.2%.36 This difference is typical in arthroplasty outcomes, due to a combination of factors such as learning curve, familiarity with implant and possible reporting bias. The Canadian Orthopaedic Foot and Ankle Society (COFAS) group7 reported on a prospective outcome study of 281 TARs, and found a major complication rate of 19% and revision rate of 17% at a mean follow-up of 5 years. Taking the time period from our earliest performed ankle replacement included in this study to the final scan performed, our failure rate using revision as an endpoint was 12% at 8 years. This is comparable with the literature for non-surgeon-designer series. Sproule et al,30 in a prospective multicenter study on the Mobility TAA system implanted in 85 patients, found that radiographic bone implant interface abnormalities were found in 43% of ankles. The majority (91%) of these involved the tibial plate. In 2 ankles, bone-implant interface abnormalities were demonstrated around the tibial stem, and in 1 ankle, they were demonstrated around the talar component. Wood et al35 reported only 14 out of 100 implanted mobility TARs showed areas of loosening at the bone-implant interface. Only 1 of these involved the talar component and in addition there was 1 case of talar subsidence. Data from the Swedish joint registry places time from index surgery to revision for loosening of tibial component at a mean of 2.5 years, loosening of talus and tibia at mean 5.3 years, and loosening of the talus at a mean 7.8 years for all prosthesis.10 We hypothesize that this increase in time to talus failure is the result of the inability to diagnose prosthetic loosening on conventional radiology due to the complex talar prosthesis anatomy. Only when loosening becomes
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Mason et al severe, resulting in talar subsidence or cystic formation is the problem apparent. Muir et al24 reporting on the outcomes of the Mobility TAR, elected not to analyze lucency around the talar component because of difficulties in their assessment. This illustrates the underreporting of talar loosening, a problem with which the SPECT-CT imaging has demonstrated the most common site for bone-prosthesis interface nonintegration. We accept that this is a case specific retrospective study without control, and thus has limitations. Without a control group we cannot confirm if this tracer uptake would not be present in a pain free TAR. SPECT-CT imaging used in total knee arthroplasty is increasingly being recognized as a promising imaging modality.13,15 Hirschmann,13 who has been a major protagonist on the use of SPECT-CT in painful knee arthroplasty, has admitted that the influencing factors such as time from primary arthroplasty surgery, patient morbidity, the patient’s individual tracer variety, and the leg’s mechanical and anatomical alignment have not been investigated and as such we must take caution in attributing our findings solely to implant loosening. In conclusion, the finding of a high incidence of talar nonintegration illustrates the limitations of conventional radiology in follow-up of TARs. However the use of SPECT-CT is expensive, very time-consuming, and not available in all centers. The increased tracer uptake can be due to a variety of causes and further studies are required to ascertain if it is possible to create pathology-specific distribution patterns. Ongoing medial sided pain has been a reported enigma in TARs. In our series, SPECT-CT imaging revealed a high incidence of medial sided talar prosthesis loosening consistent with our subsequent intraoperative findings. The high incidence of talar nonintegration should be suspected as a cause for ongoing medial sided pain. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Barg A, Henninger HB, Knupp M, Hintermann B. Simultaneous bilateral total ankle replacement using a 3-component prosthesis. Acta Orthopaedica. 2011;82:704-710. 2. Barg A, Pagenstert GI, Hügle T, et al. Ankle osteoarthritis: etiology, diagnostics, and classification. Foot Ankle Clin. 2013;18:411-426. 3. Barg A, Suter T, Zwicky L, Knupp M, Hintermann B. Medial pain syndrome in patients with total ankle replacement. Der Orthopade. 2011;40:991-992, 994-999. 4. Bestic JM, Bancroft LW, Peterson JJ, Kransdorf MJ. Postoperative imaging of the total ankle arthroplasty. Radiol
Clin North Am. 2008;46:1003-1015, v-vi. http://dx.doi. org/10.1016/j.rcl.2008.08.002. 5. Bestic JM, Peterson JJ, DeOrio JK, et al. Postoperative evaluation of the total ankle arthroplasty. AJR Am J Roentgenol. 2008;190:1112-1123. http://dx.doi.org/10.2214/ AJR.07.2729. 6. Bonnin M, Judet T, Colombier JA, et al. Midterm results of the Salto total ankle prosthesis. Clin Orthop Relat Res. 2004;424:6-18. 7. Daniels TR, Younger AS, Penner M, et al. Intermediateterm results of total ankle replacement and ankle arthrodesis: a COFAS multicenter study. J Bone Joint Surg Am. 2014;96:135-142. http://dx.doi.org/10.2106/JBJS.L.01597. 8. Gougoulias N, Khanna A, Maffulli N. How successful are current ankle replacements? A systematic review of the literature. Clin Orthop Relat Res. 2010;468:199-208. 9. Groves AM, Bird N, Tabor I, Cheow HK, Balan KK. 16-Detector multislice CT-skeletal scintigraphy image coregistration. Nucl Med Commun. 2004;25:1151-1155. 10. Henricson A, Nilsson JA, Carlsson A. 10-year survival of total ankle arthroplasties. A report on 780 cases from the Swedish Ankle Register. Acta Orthopaedica. 2011;82:655-659. 11. Hintermann B, Valderrabano V, Dereymaeker G, Dick W. The HINTEGRA ankle: rationale and short-term results of 122 consecutive ankles. Clin Orthop Relat Res. 2004;424:57-68. 12. Hintermann B, Zwicky L, Knupp M, Henninger HB, Barg A. HINTEGRA revision arthroplasty for failed total ankle prostheses. J Bone Joint Surg Am. 2013;95:1166-1174. http:// dx.doi.org/10.2106/JBJS.L.00538. 13. Hirschmann MT, Henckel J, Rasch H. SPECT/CT in patients with painful knee arthroplasty—what is the evidence? Skeletal Radiol. 2013;42:1201-1207. 14. Hirschmann MT, Iranpour F, Davda K, et al. Combined single-photon emission computerized tomography and conventional computerized tomography (SPECT/CT):clinical value for the knee surgeons? Knee Surg Sports Traumatol Arthrosc. 2010;18:341-345. http://dx.doi.org/10.1007/s00167009-0879-9. 15. Hirschmann MT, Konala P, Iranpour F, et al. Clinical value of SPECT/CT for evaluation of patients with painful knees after total knee arthroplasty—a new dimension of diagnostics? BMC Musculoskelet Disord. 2010;12:36. http://dx.doi. org/10.1186/1471-2474-12-36. 16. Hirschmann MT, Wagner CR, Rasch H, Henckel J. Standardized volumetric 3D-analysis of SPECT/CT imaging in orthopaedics: overcoming the limitations of qualitative 2D analysis. BMC Med Imaging. 2012;12:5. http://dx.doi. org/10.1186/1471-2342-12-5. 17. Kim BS, Choi WJ, Kim J, Lee JW. Residual pain due to soft-tissue impingement after uncomplicated total ankle replacement. Bone Joint J. 2013;95-B:378-383. http://dx.doi. org/10.1302/0301-620X.95B3.31219. 18. Knupp M, Pagenstert GI, Barg A, et al. SPECT-CT Compared with Conventional Imaging Modalities for the Assessment of the Varus and Valgus Malaligned Hindfoot. J Orthop Res. 2009;27:1461-1466. 19. Kopp FJ, Patel MM, Deland JT, O’Malley MJ. Total ankle arthroplasty with the Agility prosthesis: clinical and radiographic evaluation. Foot Ankle Int. 2006;27(2):97-103.
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20. Kotnis R, Pasapula C, Anwar F, Cooke PH, Sharp RJ. The management of failed ankle replacement. J Bone Joint Surg Br. 2006;88:1039-1047. http://dx.doi.org/10.1302/0301620X.88B8.16768. 21. Kurup HV, Taylor GR. Medial impingement after ankle replacement. Int Orthop. 2008;32:243-246. 22. Leumann A, Valderrabano V, Plaass C, et al. A novel imaging method for osteochondral lesions of the talus— comparison of SPECT-CT with MRI. Am J Sports Med. 2011;39:1095-1101. 23. Mohan HK, Gnanasegaran G, Vijayanathan S, Fogelman I. SPECT/CT in imaging foot and ankle pathology—the demise of other coregistration techniques. Semin Nucl Med. 2010;40:41-51. 24. Muir D, Aoina J, Hong T, Mason R. The outcome of the Mobility total ankle replacement at a mean of four years. Can poor outcomes be predicted from pre- and post-operative analysis? Bone Joint J. 2013;95-B:1366-1371. 25. Pagenstert GI, Barg A, Leumann AG, et al. SPECT-CT imaging in degenerative joint disease of the foot and ankle. J Bone Joint Surg Br. 2009;91-B:1191-1196. 26. Rippstein PF. Clinical experiences with three differ ent designs of ankle prostheses. Foot Ankle Clin. 2002;7: 817-831. 27. Rippstein PF, Huber M, Coetzee JC, Naal FD. Total ankle replacement with use of a new three-component implant. J Bone Joint Surg Am. 2011;93A:1426-1435.
28. Saltzman CL, el-Khoury GY. The hindfoot alignment view. Foot Ankle Int. 1996;16(9):572-576. 29. San Giovanni TP, Keblish DJ, Thomas WH, Wilson MG. Eight-year results of a minimally constrained total ankle arthroplasty. Foot Ankle Int. 2006;27(6):418-426. 30. Sproule JA, Chin T, Amin A, et al. Clinical and radiographic outcomes of the mobility total ankle arthroplasty system: early results from a prospective multicenter study. Foot Ankle Int. 2013;34(4):491-497. 31. Toloza EM, Harpole L, McCrory DC. Noninvasive staging of non-small cell lung cancer. Chest. 2003;123:137-146. 32. Valderrabano V, Hintermann B, Dick W. Scandinavian total ankle replacement: a 3.7-year average followup of 65 patients. Clin Orthop Relat Res. 2006;(424):47-56. 33. Valderrabano V, Pagenstert G, Horisberger M, Knupp M, Hintermann B. Sports and recreation activity of ankle arthritis patients before and after total ankle replacement. Am J Sports Med. 2006;34(4):993-999. http://dx.doi. org/10.1177/0363546505284189. 34. Williams T, Cullen N, Goldberg A, Singh D. SPECT-CT imaging of obscure foot and ankle pain. Foot Ankle Surg. 2012;18:30-33. 35. Wood PLR, Karski MT, Watmough P. Total ankle replacement. The results of 100 mobility total ankle replacements. J Bone Joint Surg Br. 2010;92-B:958-962. 36. Zaidi R, Cro S, Gurusamy K, et al. The outcome of total ankle replacement. A systematic review and meta-analysis. Bone Joint J. 2013;95-B:1500-1507.
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research-article2015
FAIXXX10.1177/1071100715573050Foot & Ankle InternationalMason et al
Article
Single-Photon-Emission Computed Tomography in Painful Total Ankle Replacements
Foot & Ankle International® 2015, Vol. 36(6) 635–640 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100715573050 fai.sagepub.com
Lyndon W. Mason, MB BCh, MRCS (Eng), FRCS (Tr&Orth)1, James Wyatt, MB ChB1, Clifford Butcher, MB ChB, FRCS (Ed), FRCS (Tr&Orth)1, Hülya Wieshmann, MRCP, FRCR1, and Andrew P. Molloy, MB ChB, MRCS (Ed), FRCS (Tr&Orth)1
Abstract Background: The use of single-photon-emission computed tomography (SPECT) in identifying unexplained pain in the foot and ankle has been described, where other imaging modalities have failed. The investigation of a painful total ankle replacement (TAR) is difficult, often not delineating a definitive cause. Our aim in this study was to investigate the use of SPECT-CT imaging in painful TARs. Methods: We performed a retrospective analysis of SPECT imaging performed for painful TARs in our department between October 2010 and December 2014. There were 14 patients identified who had undergone SPECT-CT imaging for a painful TAR. The mean age was 63.1 years, with a male/female sex ratio of 2:3 and a minimum time from surgery to imaging of 18 months. Results: Of the 14 patients, 13 were positive for increased osteoblastic activity in relation to the periprosthetic area consistent with implant loosening. The most common finding was tracer activity in relation to the talar component in 13 cases. There was additional tracer activity localized to the tibial component in 5 of these cases. In 10 of the 13 cases with prosthetic loosening/failure of bony ongrowth, there was no evidence of loosening on the plain radiographs. Infection was ruled out by using joint aspiration as clinically indicated. Conclusion: In our series, SPECT-CT imaging revealed a high incidence of medial sided talar prosthesis activity consistent with loosening. The finding of a high incidence of talar nonintegration illustrates the limitations of conventional radiology in follow-up of total ankle replacements, as this was not apparent on plain radiographs. We therefore conclude that there should be a high index of suspicion for talar prosthesis nonintegration in patients with otherwise unexplained ongoing medial pain in total ankle replacements. Level of Evidence: Level IV, retrospective case series. Keywords: SPECT, total ankle replacement, failure, aseptic loosening, talar loosening, medial pain The combination of conventional anatomical and functional imaging (hybrid imaging) has proven its value in recent years. The use of 18-Fluorine-FDG positron emission tomography (PET CT) imaging in oncology imaging has shown to have both higher sensitivity and specificity than conventional radiology in the identification of metastasis.31 The increasing use and development of hybrid imaging in musculoskeletal medicine has resulted from the developing success in other medical specialties. In 2005, Groves et al9 described the technique of coregistering bone single-photon-emission computed tomography (SPECT) images of the wrist with multislice CT images using computer software. Since the technique’s presentation, hybrid scanners where SPECT and CT are combined in a single system (SPECT-CT)
have been introduced to the market. The use of SPECT-CT has been advocated in foot and ankle surgery in the assessment of osteoarthritis, postarthrodesis pain, biological activity of talar osteochondral defect, tendinopathies, stress fractures, hindfoot deformity, and coalitions.2,18,22,23,25,34 SPECT-CT imaging has even been used to identify the source of obscure foot and ankle pain.34
1
University Hospital Aintree, Liverpool, UK
Corresponding Author: Lyndon W. Mason, MB BCh, MRCS (Eng), FRCS (Tr&Orth), University Hospital Aintree, Lower Lane, Liverpool, L9 7AL, UK. Email: [email protected]
Downloaded from fai.sagepub.com at UNIV NEBRASKA LIBRARIES on October 9, 2015
636
Foot & Ankle International 36(6)
The investigation of a painful total ankle replacement (TAR) is difficult, often not defining a conclusive cause. The most common explanations for persistent pain following a TAR include impingement, infection, aseptic loosening, instability, fracture, malposition of the prosthetic components, arthrofibrosis, and cyst formation. Delineating between these causes is difficult, and even with keen clinical acumen and the use of numerous investigations the cause can remain elusive. Recommended investigations of a painful TAR include blood inflammatory markers (ESR, CRP), linear measurements on serial radiological examinations (angular measurement change of 5 degrees, subsidence of talar component on lateral radiograph of 5 mm, radiolucent lines greater than 2 mm or a progressive increase in radiolucency can suggest loosening), and CT.4,5,20 Hintermann et al12 described the use of SPECT-CT as a routine investigation in their workup of a failed TAR. Although a number of authors have alluded to the use of SPECT-CT in identifying loosening or subsidence in TAR, no study has specifically investigated SPECT-CT use in the investigation of painful TAR.1,25 SPECT-CT use in the investigation of painful total knee replacements is more prevalent in the literature, however the natural history and intensity of tracer uptake in relation to different components is relatively unknown with no published studies including control groups.13-16 The tracer uptake identified on SPECT-CT is the result of an increased blood flow and presentation of radiotracer resulting in an increased deposition in any pathology causing hyperemia. This in turn increases the delivery of radiopharmaceuticals to the bone’s osteoblasts. The visually evident increased tracer activity on bone imaging can be due to a number of causes including physiological bone repair as a result of trauma or failure of ongrowth, hypersensitivity reaction to prosthesis material with subsequent loosening, malignancy, infection, and foreign body reaction to implants. The primary purpose of this study was to evaluate the clinical value of SPECT/CT in patients with ongoing pain following TAR. The hypothesis was that the use of SPECT/ CT would have substantial clinical importance in terms of establishment of a diagnosis in patients with ongoing pain following TAR.
Methods We completed a retrospective analysis of SPECT-CT imaging (SPECT-CT imaging performed by Symbia T2; Siemens, Munich, Germany), used for investigation of painful TARs in our department. The study was performed between October 2010 and December 2014, from the date we gained access to SPECT-CT within our department. Patients who underwent TAR in our unit would be routinely seen in our outpatient department at 2 weeks, 6 weeks, 3 months, 6 months, and 12 months postsurgery. They would
then be routinely followed yearly. Serial weight-bearing anteroposterior, lateral weight-bearing radiographs and Saltzman alignment views were taken at 6 weeks, 3 months, 6 months, and yearly.28 Unremitting pain after 12 months postsurgery was investigated initially with inflammatory markers (full blood count, C-reactive protein, and erythrocyte sedimentation rate) and plain radiographs. SPECT-CT imaging was requested in all cases where the pain continued over 1 year postsurgery. Any suspicion of infection clinically and/or through investigation prompted joint aspiration and microbiological culture. There were 14 patients identified who had undergone SPECT-CT imaging for a painful TAR. The mean age was 63.1 years (range 34-78), with a male to female sex ratio of 2:3. The minimum time from indicative surgery to undergoing SPECT-CT imaging was 18 months. The implants used in this cohort included 11 Mobility® TARs and 3 Buechel-Pappas TARs. For this study, clinical information was gathered from the patient’s documentation and all other relevant imaging was reviewed for the presented cases. The routine nuclear medicine imaging protocol includes spot planar views and SPECT-CT of the lower limbs at 2-hours after the injection of 740 MBq 99mTechnetium labeled Methylene Diphosphonate (99mTc MDP). During the time period covered in this study and the prestudy lead-up to the use of SPECT-CT within our department, there were 66 TARs performed by our 2 senior authors. Both senior authors were fellowship-trained foot and ankle surgeons who performed TAR as part of their routine clinical practice. A mixture of the Mobility total ankle arthroplasty system (DePuy International Ltd, Leeds, UK) and its predecessor the Buechel-Pappas® TAR (Wright Cremascoli Orthopaedics, Europe) were used during this period, dictated by surgeon preference and clinical need. Neither of these devices are currently FDA approved.
Results Of the 14 patients, 13 were positive for increased osteoblastic activity in relation to the periprosthetic area. The abnormal tracer activity in our cohort most commonly localized to the talar component, with 12 cases. The medial aspect of the implant was more commonly afflicted. In 4 of these cases there was abnormal tracer activity around the tibial component also. In 1 case with talar component tracer activity, tracer also localized to the subtalar joint, in keeping with arthropathy. There was 1 case of isolated tibial component activity. There was 1 case negative for osteoblastic activity and infection, where no source for the pain was found. All cases underwent weight-bearing anteroposterior and lateral radiographs of the ankle joint and Saltzman alignment views. Of these, 10 cases showed no evidence of abnormality either osseous or implant related (Figures 1a-b). The remaining 4 cases, showed some abnormality. In 1 case, there was subtalar osteoarthritic change, which corresponded
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Figure 1. Postoperative weight-bearing anteroposterior and lateral radiographs of a painful Mobility total ankle replacement, 4 years following implantation. There is satisfactory alignment and no obvious loosening of the implants.
to that found on SPECT-CT. This was combined with tibial component malalignment although there was no tracer activity in relation to the tibial component, however the talar component had increased activity. One case showed loosening of the tibial component, and this correlated with the SPECT-CT findings, however again the talar component SPECT-CT activity was not demonstrated on plain radiography. There were 2 cases that exhibited talar component lucency, 1 of which with cystic change, both corresponding to the SPECT-CT findings. In all cases, there was no clinical evidence to indicate infection. As part of the routine investigation of a painful prosthesis, inflammatory markers were obtained, but did not show any abnormality in any case. Two cases underwent joint aspiration and microbiology culture, which yielded no microbiological growth. The results of the SPECT-CT imaging, was instrumental in further treatment of this patient cohort. Following the results, 5 patients underwent revision of the ankle replacement to another replacement, 3 underwent conversion of TAR to fusion, 1 patient underwent subtalar fusion, and 4 patients following discussion decided to remain under review. Of the 8 TARs that underwent operative intervention, all displayed poor bony ongrowth in relation to the area indicated with SPECT-CT imaging (Figures 2, 3). Intraoperative sampling at the time of the operation showed no evidence of infection.
Discussion Zaidi36 performed a meta-analysis of TAR outcomes, which included 58 articles with 7942 TARs. They found that the
AOFAS and visual analogue scale scores for pain showed statistically significant improvements 10 years postoperatively. Pain relief, however, is not always complete, with between 24 and 75% reporting no pain at latest followup.1,6,11,17,19,29,32,33 Significant ongoing pain following TAR has been reported in up to 60% of cases.8 In our study, a total of 14 TARs from 66 implanted (21%) experienced significant ongoing pain in relation to the ankle requiring further investigation. Specifically, ongoing medial-sided pain has been associated with the Mobility implant and its predecessor the Buechel-Pappas TAR, with Muir et al24 reporting 14% (18 of 129) of ongoing pain at 4 years with the Mobility, and Kurup and Taylor21 reported 23.5% (8 of 34) medial associated pain with the Buechel-Pappas implant.21,24,27,35 Medial pain is not limited to these implants however, with Rippstein26 reporting occurrence in the Scandinavian Total Ankle Replacement (STAR®) stating that the cause of persistent pain was contact of the talar component with the malleoli. Kim et al17 reported an incidence of medial pain in 47.3% (of 120 ankles) when using the Hintegra system. Barg et al3 classified the etiology of the medial pain in TARs into either impingement/contracture of the medial ligaments or varus/ valgus malalignment. They stated however, that implant failure should not be underestimated. Kurup and Taylor21 implicated medial impingement and ongoing gutter arthritis as the cause of the medial pain, and reported success in 2 cases where debridement was undertaken. Kim et al17 also described success in 7 patients who underwent arthroscopic medial gutter debridement who had ongoing medial sided
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Figure 2. SPECT-CT showing talar component tracer activity.
Figure 3. Explanted Mobility talar component of the same patient with only a small bony island of ongrowth visible.
ankle pain. In our series, SPECT-CT imaging revealed a high incidence of medial sided talar prosthesis loosening. This finding was not apparent on plain radiographs, and we suspect this cause for ongoing medial sided pain has been underreported. Zaidi et al36 found that radiological outcomes were reported in 26 articles (3045 ankles). At a mean follow-up of 4.4 years, radiolucencies were reported adjacent to a mean of 21% of the tibial and 1.4% of the talar components. This meta-analysis also found that the best reported results to be by surgeon designers, who reported a mean annual failure rate (AFR) of 1.1%.36 In contrast, published
literature from non-surgeon-designers reported a mean AFR of 1.7%, and national joint registries reported a mean AFR of 3.2%.36 This difference is typical in arthroplasty outcomes, due to a combination of factors such as learning curve, familiarity with implant and possible reporting bias. The Canadian Orthopaedic Foot and Ankle Society (COFAS) group7 reported on a prospective outcome study of 281 TARs, and found a major complication rate of 19% and revision rate of 17% at a mean follow-up of 5 years. Taking the time period from our earliest performed ankle replacement included in this study to the final scan performed, our failure rate using revision as an endpoint was 12% at 8 years. This is comparable with the literature for non-surgeon-designer series. Sproule et al,30 in a prospective multicenter study on the Mobility TAA system implanted in 85 patients, found that radiographic bone implant interface abnormalities were found in 43% of ankles. The majority (91%) of these involved the tibial plate. In 2 ankles, bone-implant interface abnormalities were demonstrated around the tibial stem, and in 1 ankle, they were demonstrated around the talar component. Wood et al35 reported only 14 out of 100 implanted mobility TARs showed areas of loosening at the bone-implant interface. Only 1 of these involved the talar component and in addition there was 1 case of talar subsidence. Data from the Swedish joint registry places time from index surgery to revision for loosening of tibial component at a mean of 2.5 years, loosening of talus and tibia at mean 5.3 years, and loosening of the talus at a mean 7.8 years for all prosthesis.10 We hypothesize that this increase in time to talus failure is the result of the inability to diagnose prosthetic loosening on conventional radiology due to the complex talar prosthesis anatomy. Only when loosening becomes
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Mason et al severe, resulting in talar subsidence or cystic formation is the problem apparent. Muir et al24 reporting on the outcomes of the Mobility TAR, elected not to analyze lucency around the talar component because of difficulties in their assessment. This illustrates the underreporting of talar loosening, a problem with which the SPECT-CT imaging has demonstrated the most common site for bone-prosthesis interface nonintegration. We accept that this is a case specific retrospective study without control, and thus has limitations. Without a control group we cannot confirm if this tracer uptake would not be present in a pain free TAR. SPECT-CT imaging used in total knee arthroplasty is increasingly being recognized as a promising imaging modality.13,15 Hirschmann,13 who has been a major protagonist on the use of SPECT-CT in painful knee arthroplasty, has admitted that the influencing factors such as time from primary arthroplasty surgery, patient morbidity, the patient’s individual tracer variety, and the leg’s mechanical and anatomical alignment have not been investigated and as such we must take caution in attributing our findings solely to implant loosening. In conclusion, the finding of a high incidence of talar nonintegration illustrates the limitations of conventional radiology in follow-up of TARs. However the use of SPECT-CT is expensive, very time-consuming, and not available in all centers. The increased tracer uptake can be due to a variety of causes and further studies are required to ascertain if it is possible to create pathology-specific distribution patterns. Ongoing medial sided pain has been a reported enigma in TARs. In our series, SPECT-CT imaging revealed a high incidence of medial sided talar prosthesis loosening consistent with our subsequent intraoperative findings. The high incidence of talar nonintegration should be suspected as a cause for ongoing medial sided pain. Declaration of Conflicting Interests The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding The author(s) received no financial support for the research, authorship, and/or publication of this article.
References 1. Barg A, Henninger HB, Knupp M, Hintermann B. Simultaneous bilateral total ankle replacement using a 3-component prosthesis. Acta Orthopaedica. 2011;82:704-710. 2. Barg A, Pagenstert GI, Hügle T, et al. Ankle osteoarthritis: etiology, diagnostics, and classification. Foot Ankle Clin. 2013;18:411-426. 3. Barg A, Suter T, Zwicky L, Knupp M, Hintermann B. Medial pain syndrome in patients with total ankle replacement. Der Orthopade. 2011;40:991-992, 994-999. 4. Bestic JM, Bancroft LW, Peterson JJ, Kransdorf MJ. Postoperative imaging of the total ankle arthroplasty. Radiol
Clin North Am. 2008;46:1003-1015, v-vi. http://dx.doi. org/10.1016/j.rcl.2008.08.002. 5. Bestic JM, Peterson JJ, DeOrio JK, et al. Postoperative evaluation of the total ankle arthroplasty. AJR Am J Roentgenol. 2008;190:1112-1123. http://dx.doi.org/10.2214/ AJR.07.2729. 6. Bonnin M, Judet T, Colombier JA, et al. Midterm results of the Salto total ankle prosthesis. Clin Orthop Relat Res. 2004;424:6-18. 7. Daniels TR, Younger AS, Penner M, et al. Intermediateterm results of total ankle replacement and ankle arthrodesis: a COFAS multicenter study. J Bone Joint Surg Am. 2014;96:135-142. http://dx.doi.org/10.2106/JBJS.L.01597. 8. Gougoulias N, Khanna A, Maffulli N. How successful are current ankle replacements? A systematic review of the literature. Clin Orthop Relat Res. 2010;468:199-208. 9. Groves AM, Bird N, Tabor I, Cheow HK, Balan KK. 16-Detector multislice CT-skeletal scintigraphy image coregistration. Nucl Med Commun. 2004;25:1151-1155. 10. Henricson A, Nilsson JA, Carlsson A. 10-year survival of total ankle arthroplasties. A report on 780 cases from the Swedish Ankle Register. Acta Orthopaedica. 2011;82:655-659. 11. Hintermann B, Valderrabano V, Dereymaeker G, Dick W. The HINTEGRA ankle: rationale and short-term results of 122 consecutive ankles. Clin Orthop Relat Res. 2004;424:57-68. 12. Hintermann B, Zwicky L, Knupp M, Henninger HB, Barg A. HINTEGRA revision arthroplasty for failed total ankle prostheses. J Bone Joint Surg Am. 2013;95:1166-1174. http:// dx.doi.org/10.2106/JBJS.L.00538. 13. Hirschmann MT, Henckel J, Rasch H. SPECT/CT in patients with painful knee arthroplasty—what is the evidence? Skeletal Radiol. 2013;42:1201-1207. 14. Hirschmann MT, Iranpour F, Davda K, et al. Combined single-photon emission computerized tomography and conventional computerized tomography (SPECT/CT):clinical value for the knee surgeons? Knee Surg Sports Traumatol Arthrosc. 2010;18:341-345. http://dx.doi.org/10.1007/s00167009-0879-9. 15. Hirschmann MT, Konala P, Iranpour F, et al. Clinical value of SPECT/CT for evaluation of patients with painful knees after total knee arthroplasty—a new dimension of diagnostics? BMC Musculoskelet Disord. 2010;12:36. http://dx.doi. org/10.1186/1471-2474-12-36. 16. Hirschmann MT, Wagner CR, Rasch H, Henckel J. Standardized volumetric 3D-analysis of SPECT/CT imaging in orthopaedics: overcoming the limitations of qualitative 2D analysis. BMC Med Imaging. 2012;12:5. http://dx.doi. org/10.1186/1471-2342-12-5. 17. Kim BS, Choi WJ, Kim J, Lee JW. Residual pain due to soft-tissue impingement after uncomplicated total ankle replacement. Bone Joint J. 2013;95-B:378-383. http://dx.doi. org/10.1302/0301-620X.95B3.31219. 18. Knupp M, Pagenstert GI, Barg A, et al. SPECT-CT Compared with Conventional Imaging Modalities for the Assessment of the Varus and Valgus Malaligned Hindfoot. J Orthop Res. 2009;27:1461-1466. 19. Kopp FJ, Patel MM, Deland JT, O’Malley MJ. Total ankle arthroplasty with the Agility prosthesis: clinical and radiographic evaluation. Foot Ankle Int. 2006;27(2):97-103.
Downloaded from fai.sagepub.com at UNIV NEBRASKA LIBRARIES on October 9, 2015
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20. Kotnis R, Pasapula C, Anwar F, Cooke PH, Sharp RJ. The management of failed ankle replacement. J Bone Joint Surg Br. 2006;88:1039-1047. http://dx.doi.org/10.1302/0301620X.88B8.16768. 21. Kurup HV, Taylor GR. Medial impingement after ankle replacement. Int Orthop. 2008;32:243-246. 22. Leumann A, Valderrabano V, Plaass C, et al. A novel imaging method for osteochondral lesions of the talus— comparison of SPECT-CT with MRI. Am J Sports Med. 2011;39:1095-1101. 23. Mohan HK, Gnanasegaran G, Vijayanathan S, Fogelman I. SPECT/CT in imaging foot and ankle pathology—the demise of other coregistration techniques. Semin Nucl Med. 2010;40:41-51. 24. Muir D, Aoina J, Hong T, Mason R. The outcome of the Mobility total ankle replacement at a mean of four years. Can poor outcomes be predicted from pre- and post-operative analysis? Bone Joint J. 2013;95-B:1366-1371. 25. Pagenstert GI, Barg A, Leumann AG, et al. SPECT-CT imaging in degenerative joint disease of the foot and ankle. J Bone Joint Surg Br. 2009;91-B:1191-1196. 26. Rippstein PF. Clinical experiences with three differ ent designs of ankle prostheses. Foot Ankle Clin. 2002;7: 817-831. 27. Rippstein PF, Huber M, Coetzee JC, Naal FD. Total ankle replacement with use of a new three-component implant. J Bone Joint Surg Am. 2011;93A:1426-1435.
28. Saltzman CL, el-Khoury GY. The hindfoot alignment view. Foot Ankle Int. 1996;16(9):572-576. 29. San Giovanni TP, Keblish DJ, Thomas WH, Wilson MG. Eight-year results of a minimally constrained total ankle arthroplasty. Foot Ankle Int. 2006;27(6):418-426. 30. Sproule JA, Chin T, Amin A, et al. Clinical and radiographic outcomes of the mobility total ankle arthroplasty system: early results from a prospective multicenter study. Foot Ankle Int. 2013;34(4):491-497. 31. Toloza EM, Harpole L, McCrory DC. Noninvasive staging of non-small cell lung cancer. Chest. 2003;123:137-146. 32. Valderrabano V, Hintermann B, Dick W. Scandinavian total ankle replacement: a 3.7-year average followup of 65 patients. Clin Orthop Relat Res. 2006;(424):47-56. 33. Valderrabano V, Pagenstert G, Horisberger M, Knupp M, Hintermann B. Sports and recreation activity of ankle arthritis patients before and after total ankle replacement. Am J Sports Med. 2006;34(4):993-999. http://dx.doi. org/10.1177/0363546505284189. 34. Williams T, Cullen N, Goldberg A, Singh D. SPECT-CT imaging of obscure foot and ankle pain. Foot Ankle Surg. 2012;18:30-33. 35. Wood PLR, Karski MT, Watmough P. Total ankle replacement. The results of 100 mobility total ankle replacements. J Bone Joint Surg Br. 2010;92-B:958-962. 36. Zaidi R, Cro S, Gurusamy K, et al. The outcome of total ankle replacement. A systematic review and meta-analysis. Bone Joint J. 2013;95-B:1500-1507.
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