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Incidence of Nonunion After Isolated Arthroscopic Ankle Arthrodesis
Systematic Review
Incidence of Nonunion After Isolated Arthroscopic Ankle Arthrodesis Bradley P. Abicht, D.P.M., A.A.C.F.A.S., and Thomas S. Roukis, D.P.M., Ph.D., F.A.C.F.A.S.
Purpose: To determine the incidence of nonunion after isolated arthroscopic ankle arthrodesis. Methods: Electronic databases and relevant peer-reviewed sources, including OvidSP/Medline (http://ovidsp.tx.ovid.com) and Google, were systematically searched for the terms “arthroscopic ankle arthrodesis” AND “nonunion”. Additionally, we manually searched common American, British, and European orthopaedic and podiatric scientific literature for relevant articles. Studies were eligible for inclusion only if they included the following: isolated ankle arthrodesis, greater than 20 ankles, minimum mean follow-up of 12-months, a 2-portal anterior arthroscopic approach, fixation with 2 or 3 large-diameter cannulated cancellous screws, and the nonunion rate with no restriction on cause. Results: After considering all the potentially eligible articles, 7 (25.9%) met the inclusion criteria. A total of 244 patients (244 ankles)d148 (60.7%) male and 96 (39.3%) female patients, with a weighted mean age of 49.2 yearsdwere included. For those studies that specified the exact follow-up, the weighted mean was 24.1 months. A total of 21 nonunions (8.6%) were reported, with 14 (66.7%) being symptomatic and requiring further intervention. Conclusions: The results of this systematic review reveal an acceptable incidence of nonunion of 8.6%. However it is important to recognize that of these nonunions, 66.7% were symptomatic. This supports the belief that regardless of approach, nonunion of an ankle arthrodesis is problematic. In light of this finding, additional prospective studies are warranted to compare directly the incidence of nonunion between open, minimum incision, and arthroscopic approaches with a variety of fixation constructs. Level of Evidence: Level IV, systematic review of level IV studies.
A
rthrodesis has been proved an acceptable treatment for myriad pathologic conditions involving the ankle joint. Surgical approaches previously described include open, minimum incision, and arthroscopic. Current literature includes reports of successful symptomatic relief in addition to improved function after ankle arthrodesis, regardless of the surgical approach used.1-9 Schneider10 was the first to describe ankle arthrodesis using an arthroscopic approach and reported faster time to union, quicker mobilization, and decreased patient morbidity relative to open approaches (Fig 1). Since this initial report, a plethora of other studies have confirmed
From Department of Orthopaedics (B.P.A; T.S.R.), Podiatry & Sports Medicine, Gundersen Lutheran Medical Center, La Crosse, Wisconsin, U.S.A. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received October 5, 2012; accepted December 4, 2012. Address correspondence to Bradley P. Abicht, D.P.M., Department of Orthopaedics, Podiatry & Sports Medicine, Gundersen Lutheran Medical Center, Second Floor Founder’s Building, 1900 South Avenue, La Crosse, WI 54601. E-mail: [email protected] Ó 2013 by the Arthroscopy Association of North America 0749-8063/12656/$36.00 http://dx.doi.org/10.1016/j.arthro.2012.12.001
his findings.11-21 Recent studies have shown numerous benefits of the arthroscopic approach, including reduction in hospitalization time, as well as in pain, edema, complications, and expense, while simultaneously exhibiting faster time to recovery and fusion.21-27 However regardless of the surgical technique used, nonunion is a known potential complication with significant consequences. It can lead to continued pain, edema, and instability and may require additional or revision surgery, which adds to patient recovery time and increases health care expenses. Despite reports of nonunion being a potential consequence of ankle arthrodesis, irrespective of surgical approach used, the exact incidence of nonunion after arthroscopic ankle arthrodesis remains unknown. In an effort to determine the actual incidence of nonunion after arthroscopic ankle arthrodesis, we undertook a systematic review.
Methods The authors performed a systematic review of electronic databases and relevant peer-reviewed sources including OvidSP/MEDLINE (http://ovidsp.tx.ovid.com) and a general search engine (http://www.google.com). Additionally, we manually searched common American,
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 29, No 5 (May), 2013: pp 949-954
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Fig 1. (A) Arthroscopic image through standard anterolateral portal shows use of ring curette for debridement of remaining talar and tibial cartilaginous surfaces with exposure of subchondral bone plate. (B) Standard anteromedial portal view shows acromionizer debriding through subchondral bone plate down to appropriate level of raw bleeding bone. (C) Intraoperative image intensification through lateral view verifying acromionizer reaching posterior recess of ankle joint with noted retained internal fixation from previous ankle fracture. (D) Standard anterolateral view reveals angled gold-tipped chondral pick showing microfracture technique. (E) Standard anterolateral view reveals angled chondral pick with gold tip buried to proper level showing microfracture technique. (F) Standard anteromedial view shows ankle joint surfaces after debridement and microfracture technique, before deflating thigh tourniquet. (G) Standard anteromedial view shows ankle joint surfaces after debridement and microfracture technique, verifying raw bleeding substrate after deflation of thigh tourniquet. (H) Intraoperative image intensification of anteroposterior view of ankle after final positioning and placement of rigid internal fixation including large-fragment tripod screw construct (with noted retained medial malleolar fixation from previous ankle fracture). (I) Intraoperative image intensification of lateral view of ankle after final positioning and placement of rigid internal fixation (with noted retained medial malleolar fixation from previous ankle fracture).
British, and European orthopaedic and podiatric scientific literature for relevant articles. Only articles that included isolated ankle arthrodesis, greater than 20 ankles, minimum mean follow-up of 12-months, a 2-portal anterior arthroscopic approach, fixation with 2 or 3 largediameter cannulated cancellous screws, and a nonunion rate with no restrictions on cause were considered. We performed this systematic review between August 2011 and September 2012, with no restriction on date or language and used an inclusive text word query
“arthroscopic ankle arthrodesis” AND “nonunion” in which the uppercase words represent the Boolean operators used. All the articles were reviewed by each of us, and complete agreement was necessary for final inclusion, with the lead author (B.P.A.) being the moderator. Only full-text published articles were considered. For purposes of this review, all types of nonunion were examined, including that seen on radiography and in clinical practice, with delineation of symptomatic versus asymptomatic.
NONUNION AFTER ARTHROSCOPIC ANKLE ARTHRODESIS
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to range from less than 5%2,3,28,29 to 41%.6,30 With the advent of improved surgical techniques and advanced methods of fixation, the incidence of nonunion decreased, but the exact incidence for open approaches is not known. A recent meta-analysis comparing total ankle replacement and ankle arthrodesis found a nonunion rate of 10%, with 65% of revision procedures being performed to treat nonunions in patients with failed ankle arthrodeses.31 In our current systematic review, we found a lower incidence of nonunion (8.6%) using one fixation construct through a 2-portal arthroscopic approach. Apart from a lower incidence of nonunion, we found that the authors of the involved studies in this review repeatedly referenced additional benefits of an arthroscopic approach for isolated ankle arthrodesis, which were also noted in their respective results. Although these benefits are beyond the scope and focus of this article, they have been noted previously and include reduced time to union, shorter hospital stays, fewer complications, and decreased postoperative pain and edema.11-21 Furthermore, in regard to the current atmosphere in medical care and ongoing changes with reimbursement, there may be a fiduciary obligation for further research in this area. Specifically this would include a comparative cost analysis, patient satisfaction measurements, and investigation of overall complication rates between arthroscopic and open ankle arthrodesis procedures. These results may reveal further cost savings and improved patient care by using an arthroscopic approach.
Results The search for potentially eligible information for inclusion in the systematic review yielded a total of 27 articles. We obtained and reviewed all articles identified. We also completed an updated search for new articles in October 2012, which yielded no further studies. After considering all the potentially eligible articles, 7 (25.9%) met our inclusion criteria for the study (Fig 2).21-27 A total of 244 patients (148 [60.7%] male and 96 [39.3%] female patients) and 244 total ankles were included (Table 1). The weighted mean age of the patients was 49.2 years and the weighted mean follow-up of the studies that included the specific time of follow-up was 24.1 months. The incidence of nonunion was 8.6% (21 of 244). Fourteen of the nonunions (66.7%) were symptomatic and required further intervention. The methodologic quality of included studies was generally fair. For the studies involving arthroscopic ankle arthrodesis that met our inclusion criteria, all were full-text articles that were considered evidencebased medicine level IV studies. Furthermore, all were published in known peer-reviewed journals.
Discussion The purpose of this systematic review was to evaluate the overall incidence of nonunion after isolated arthroscopic ankle arthrodesis. Recently, the arthroscopic approach has been shown to offer numerous advantages over open or mini-open techniques. Nevertheless, nonunion remains a potential complication regardless of surgical method. To our knowledge, the overall incidence of nonunion after an isolated arthoscopic ankle arthrodesis has not been previously examined. Historically, nonunion rates after open ankle arthrodesis have been noted
Limitations Numerous weaknesses of this study were considered. First, we performed the search for articles that met
Potentially relevant articles after search in digital databases with each abstract reviewed for more information about study design or surgical procedure (n = 27)
Articles Excluded on Abstract Involved additional surgical procedures (n = 5)
Full-text articles retrieved for detailed comparison with inclusion criteria (n = 22)
Articles Excluded on Full Text Did not meet minimum number of ankles (n = 13) Used portal other than anteromedial or anterolateral (n = 1) Used fixation other than crossed screws (n = 1) Articles included in review (n = 7)
Fig 2. Flowchart of the articles during the selection process for this systematic review.
952 (4.8) (12.8) (5.2) (7.1) (15.5) (3.9) (12) (8.6) 1 5 3 3 4 1 4 21 34 (18-60) 12 (NA) for union; 20.4 (NA) for nonunion Minimum of 12 mo (NA) 27 (12-64) 18.3 (6-75) 36 (17-60) 22 (6-53) 24.1 (6-144) 8.9 (7-14) 6.7 (5.3-10) NA NA NA 10.5 (9-12) NA 8.4 (5.3-14) 95.2 87.2 94.8 92.9 84.6 96.1 88 91.4 (22-65) (40-89) (23-80) (19-75) (31-69) (26-81) (38-86) (19-89) 52.7 65 51 46 NA 52.2 66 49.2 21 39 58 42 26 26 32 244 (14/7) (14/25) (38/20) (26/16) (15/11) (18/8) (23/9) (148/96) NA, not available.
21 39 58 42 26 26 32 244 Zvijac et al.21 (2002) (IV) Collman et al.22 (2006) (IV) Nielsen et al.23 (2008) (IV) Crosby et al.24 (1996) (IV) Jerosch et al.25 (1996) (IV) Saragas26 (2004) (IV) Odutola et al.27 (2012) (IV) Total
Average Time to Union in Weeks (range) Ankle Arthrodesis Rate (%) Average Age in Years (range) Total No. of Ankles Total No. of Patients (M/F) Author (Year) (Level of Evidence)
Table 1. Statistical Description of the Studies That Met the Criteria for Inclusion in the Systematic Review
Average Follow-up in Months (range)
Total No. of Nonunions (%)
B. P. ABICHT AND T. S. ROUKIS
inclusion criteria through electronic databases. It is inherently possible that pertinent references may have been inadvertently overlooked or excluded. Moreover, the search did not include every potential electronic database and was restricted to only full-text articles. A more expansive search may have yielded supplementary articles for inclusion. In addition, the inclusion criteria were quite narrow. This produced a small subset of articles for evaluation. The fixation construct included was 2 or 3 large-diameter cannulated cancellous screws, which was by far the most common fixation construct noted throughout the literature. Patients who received a third screw may have subsequently gained a more rigid internal fixation construct, thereby influencing their risk of nonunion and altering a given article’s reported incidence of nonunion. Three versus 2 screws was not controlled for, but selecting either a 2-screw construct or a 3-screw construct would have eliminated many potential studies that were otherwise included in this review. Additionally, there was one study that involved fixation with 2 headless fully threaded cancellous screws, with the intention of obviating future screw removal secondary to prominent hardware.27 These authors were correct in their hypothesis because none of the 32 patients involved in their study required hardware removal for the duration of their published follow-up (mean follow-up of 22 months). Considering the significant options available for alternative fixation and accessory arthroscopic portals, we felt that a narrower search would better ensure critical analysis of the arthroscopic ankle arthrodesis procedure. Furthermore, the fixation construct used in our inclusion criteria is one that was noted throughout most of the potential articles reviewed. Second, the inclusion criteria eliminated studies that included adjunctive procedures with arthroscopic ankle arthrodesis, such as calcaneal osteotomy, subtalar joint arthrodesis, gastrocnemius lengthening, and so on. Excluding these studies32-34 eliminated 251 potential ankles and increased the incidence of nonunion from 7.5% to the current review’s result of 8.6%. The lower rate may be a more realistic value because adjunctive procedures are often necessary to provide patients with optimal outcomes, and sometimes these additional procedures are not anticipated until the surgeon and patient are in the intraoperative setting. Although studies that failed to involve only isolated ankle arthrodesis procedures were ultimately excluded in this review, surgeons should note that the incidence of nonunion may actually be less than the stated 8.6%, especially when indicated adjunctive procedures are performed. Third, we did not specifically examine the type and period of immobilization for the operative lower extremity in this review, nor were they involved in the inclusion criteria. However the postoperative care was not consistent throughout the included studies. In the
NONUNION AFTER ARTHROSCOPIC ANKLE ARTHRODESIS
majority of cases, patients were immobilized initially with a posterior splint and then transitioned to a short-leg cast at the first postoperative follow-up visit, in addition to being kept on a noneweight-bearing regimen for 4 to 6 weeks. One study did apply a partial weight-bearing walking cast as early as 1 week postoperatively.21 Some studies initially placed a below-knee back slab,21,26 whereas others added a U-splint22 or went straight to a complete cast23-25 for further immobilization. Furthermore, various studies used plaster, whereas others used fiberglass or did not specify what type of material was used. This variability in postoperative management may have an impact on the overall incidence of nonunion but remains a matter for conjecture. Finally, our inclusion criteria failed to address deformity. Historically, the arthroscopic approach has been reserved for end-stage ankle arthrosis for various causes with either no or minimal deformity, which is defined as less than 15 of ankle varus or valgus malalignment in the frontal plane. One study,32 which was excluded from our analysis, specifically analyzed the impact of preoperative ankle deformity, comparing 2 different cohorts treated with ankle arthrodesis through an arthroscopic approach. The first cohort in their study included patients with ankles with 15 or less varus or valgus deformity. The comparative group included patients with ankles with greater than 15 varus or valgus deformity, but no greater than 45 as measured on a standard anteroposterior weight-bearing radiograph. Both groups experienced high fusion rates and there was no statistically significant difference, with the authors stating that the arthroscopic approach may be used in cases of significant ankle deformity. A similar study,34 which was also excluded from our analysis, compared one group of patients with up to 15 varus/ valgus deformity and another group of patients with 15 degree deformity or greater that had similar findings. An overall fusion rate of 91% was noted, with a 94% fusion rate in the group with lesser deformity compared with 88% for the group with greater deformity. A third study,23 which was included in our review, pitted an arthroscopic ankle arthrodesis group of patients with minimal deformity (5 or less of varus/ valgus malalignment in the frontal plane) versus an open ankle arthrodesis group of patients with deformity (varus/valgus malalignment greater than 5 in the frontal plane). At 12 weeks there was a statistically significant difference in fusion ratesd90% in the arthroscopic group and only 57% in the open group. At 1 year the fusion rates remained greater for the arthroscopic group than for the open group, but this was not statistically significant, with fusion rates being 95% and 84%, respectively. One may infer that the arthroscopic approach requires less time to achieve union than does the open approach, but the degree of deformity was not equal across cohorts. A fourth
953
study,33 which was excluded from our analysis, did not control for ankle deformity, including 118 arthroscopic ankle arthrodesis procedures with preoperative deformity ranging from 22 valgus to 28 varus. Their incidence of nonunion was 7.6%, which is noted to be less than the results of this review (8.6%). Ultimately, the dynamics of adjunctive surgical procedures, alternative fixation constructs, postoperative immobilization preference, and degree of preoperative ankle deformity may impart significant influence on the overall incidence of nonunion associated with the arthroscopic ankle arthrodesis procedure. Future prospective studies are required to further investigate their influence on nonunion rates in arthroscopic ankle arthrodesis. Once this is identified, the incidence of nonunion may decrease further. Combining a low nonunion rate with the aforementioned benefits inherent in an arthroscopic approach, the safety and efficacy may prove superior to the traditional open approach.
Conclusions We performed a systematic review using electronic databases to determine the actual incidence of nonunion after arthroscopic ankle arthrodesis. Based on the inclusion criteria, a total of 7 studies were included in the analysis. The methodologic design of the studies was fair. Compared with published nonunion rates after traditional open techniques, the results of these studies reveal a relatively low incidence of nonunion of 8.6% (21 of 244) after isolated arthroscopic ankle arthrodesis using a standard anterior 2-portal technique with fixation using 2 or 3 large-diameter cancellous screws. However given the limited data available for review, additional prospective investigations are necessary. Furthermore, direct comparative studies on ankle arthrodesis procedures through open, mini-open, and arthroscopic approaches are warranted to further delineate the differences in nonunion rates and reveal potential supplemental benefits as described previously.
References 1. Morrey BF, Wiedeman GP. Complications and long-term results of ankle arthrodesis following trauma. J Bone Joint Surg Am 1980;62:777-784. 2. Mazur JM, Schwartz E, Simon SR. Ankle arthrodesis: Long-term follow-up with gait analysis. J Bone Joint Surg Am 1979;61:964-975. 3. Morgan CD, Henke JA, Baily RW, Kaufer H. Long-term results of tibiotalar arthrodesis. J Bone Joint Surg Am 1985;67:546-549. 4. Mann RA, Van Manen JW, Wapner K, Martin J. Ankle fusion. Clin Orthop 1991;268:49-55. 5. Ratliff AHC. Compression arthrodesis of the ankle. J Bone Joint Surg Br 1959;41:524-534. 6. Hagen RJ. Ankle arthrodesis: Problems and pitfalls. Clin Orthop Relat Res 1986;202:152-162.
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7. Lance EM, Paval A, Fries I, Larson I, Patterson RL. Arthrodesis of the ankle joint: A follow-up study. Clin Orthop 1979;142:146-158. 8. Lynch AF, Bourne RB, Rorabeck CH. The long-term results of ankle arthrodesis. J Bone Joint Surg Br 1988;70: 113-116. 9. Buck P, Morrey BF, Chao EYS. The optimum position of arthrodesis of the ankle: A gait study of the knee and ankle. J Bone Joint Surg Am 1987;69:1052-1062. 10. Schneider D. Arthroscopic ankle fusion. Arthroscopic Video J 1983;3. 11. Corso SJ, Zimmer TJ. Technique and clinical evaluation of arthroscopic ankle arthrodesis. Arthroscopy 1995;11: 585-590. 12. Ferkel RD, Hewitt M. Long-term results of arthroscopic ankle arthrodesis. Foot Ankle Int 2005;26:275-280. 13. Fisher RL, Ryan WR, Dugdale TN, Zimmermann GA. Arthroscopic ankle fusion. Conn Med 1997;61:643-646. 14. Glick JM, Morgan CD, Myerson MS, Sampson TG, Mann JA. Ankle arthrodesis using an arthroscopic method: Long term follow-up of 34 cases. Arthroscopy 1996;12:428-434. 15. Kats J, van Kampen A, de Waal-Malefijt MC. Improvement in technique for arthroscopic ankle fusion: Results in 15 patients. Knee Surg Sports Traumatol Arthrosc 2003;11: 46-49. 16. Myerson MS, Quill G. Ankle arthrodesis: a comparison of an arthroscopic and an open method of treatment. Clin Orthop 1991;268:84-95. 17. O’Brien TS, Hart TS, Shereff MJ, Stone J, Johnson J. Open versus arthroscopic ankle arthrodesis: a comparative study. Foot Ankle Int 1999;20:368-374. 18. Ogilvie-Harris DJ, Lieberman I, Fitsialos D. Arthroscopically assisted arthrodesis for osteoarthrotic ankles. J Bone Joint Surg 1993;75-A:1167-1174. 19. Pierre A, Hulet C, Locker B, Souquet D, Jambou S, Vielpeau C. Arthroscopic tibio-talar arthrodesis: Limitations and indications in 20 patients [Article in French]. Rev Chir Orthop Reparatrice Appar Mot 2003;89:144-151. 20. Turan I, Wredmark T, Fellander-Tsai L. Arthroscopic ankle arthrodesis in rheumatoid arthritis. Clin Orthop 1995;320:110-114.
21. Zvijac JE, Lemak L, Schurhoff MR, Hechtman KS, Uribe JW. Analysis of arthroscopically assisted ankle arthrodesis. Arthroscopy 2002;18:70-75. 22. Collman D, Kaas MH, Schuberth J. Arthroscopic ankle arthrodesis: Factors influencing union in 39 consecutive patients. Foot Ankle Int 2006;27:1079-1085. 23. Nielsen K, Linde F, Jensen N. The outcome of arthroscopic and open surgery ankle arthrodesis: A comparative retrospective study on 107 patients. Foot Ankle Surg 2008; 14:153-157. 24. Crosby L, Yee T, Formanek T, Fitzgibbons T. Complications following arthroscopic ankle arthrodesis. Foot Ankle Int 1996;17:340-342. 25. Jerosch J, Steinbeck J, Schröder M, Reer R. Arthroscopically assisted arthrodesis of the ankle joint. Arch Orthop Trauma Surg 1996;115:182-189. 26. Saragas N. Results of arthroscopic arthrodesis of the ankle. Foot Ankle Surg 2004;10:141-143. 27. Odutola A, Sheridan B, Kelly A. Headless compression screw fixation prevents symptomatic metalwork in arthroscopic ankle arthrodesis. Foot Ankle Surg 2012;18: 111-113. 28. Scranton P. Use of internal compression in arthrodesis of the ankle. J Bone Joint Surg Am 1985;67:550-555. 29. Stewart M, Beeler T, McConnell J. Compression arthrodesis of the ankle. Evaluation of a cosmetic modification. J Bone Joint Surg Am 1983;65:219-225. 30. Hallock H. Arthrodesis of the ankle joint for old painful fractures. J Bone Joint Surg Am 1945;27:49-58. 31. Haddad S, Coetzee J, Estok R, Fahrbach K, Banel D, Nalysnyk L. Intermediate and long-term outcomes of total ankle arthroplasty and ankle arthrodesis. A systematic review of the literature. J Bone Joint Surg Am 2007;89: 1899-1905. 32. Gougoulias N, Agathangelidis F, Parsons S. Arthroscopic ankle arthrodesis. Foot Ankle Int 2007;28:695-706. 33. Winson I, Robinson D, Allen P. Arthroscopic ankle arthrodesis. J Bone Joint Surg Br 2005;87-B:343-347. 34. Dannawi Z, Nawabi D, Patel A, Leong J, Moore D. Arthroscopic ankle arthrodesis: Are results reproducible irrespective of pre-operative deformity? Foot Ankle Surg 2011;17:294-299.
Incidence of Nonunion After Isolated Arthroscopic Ankle Arthrodesis Bradley P. Abicht, D.P.M., A.A.C.F.A.S., and Thomas S. Roukis, D.P.M., Ph.D., F.A.C.F.A.S.
Purpose: To determine the incidence of nonunion after isolated arthroscopic ankle arthrodesis. Methods: Electronic databases and relevant peer-reviewed sources, including OvidSP/Medline (http://ovidsp.tx.ovid.com) and Google, were systematically searched for the terms “arthroscopic ankle arthrodesis” AND “nonunion”. Additionally, we manually searched common American, British, and European orthopaedic and podiatric scientific literature for relevant articles. Studies were eligible for inclusion only if they included the following: isolated ankle arthrodesis, greater than 20 ankles, minimum mean follow-up of 12-months, a 2-portal anterior arthroscopic approach, fixation with 2 or 3 large-diameter cannulated cancellous screws, and the nonunion rate with no restriction on cause. Results: After considering all the potentially eligible articles, 7 (25.9%) met the inclusion criteria. A total of 244 patients (244 ankles)d148 (60.7%) male and 96 (39.3%) female patients, with a weighted mean age of 49.2 yearsdwere included. For those studies that specified the exact follow-up, the weighted mean was 24.1 months. A total of 21 nonunions (8.6%) were reported, with 14 (66.7%) being symptomatic and requiring further intervention. Conclusions: The results of this systematic review reveal an acceptable incidence of nonunion of 8.6%. However it is important to recognize that of these nonunions, 66.7% were symptomatic. This supports the belief that regardless of approach, nonunion of an ankle arthrodesis is problematic. In light of this finding, additional prospective studies are warranted to compare directly the incidence of nonunion between open, minimum incision, and arthroscopic approaches with a variety of fixation constructs. Level of Evidence: Level IV, systematic review of level IV studies.
A
rthrodesis has been proved an acceptable treatment for myriad pathologic conditions involving the ankle joint. Surgical approaches previously described include open, minimum incision, and arthroscopic. Current literature includes reports of successful symptomatic relief in addition to improved function after ankle arthrodesis, regardless of the surgical approach used.1-9 Schneider10 was the first to describe ankle arthrodesis using an arthroscopic approach and reported faster time to union, quicker mobilization, and decreased patient morbidity relative to open approaches (Fig 1). Since this initial report, a plethora of other studies have confirmed
From Department of Orthopaedics (B.P.A; T.S.R.), Podiatry & Sports Medicine, Gundersen Lutheran Medical Center, La Crosse, Wisconsin, U.S.A. The authors report that they have no conflicts of interest in the authorship and publication of this article. Received October 5, 2012; accepted December 4, 2012. Address correspondence to Bradley P. Abicht, D.P.M., Department of Orthopaedics, Podiatry & Sports Medicine, Gundersen Lutheran Medical Center, Second Floor Founder’s Building, 1900 South Avenue, La Crosse, WI 54601. E-mail: [email protected] Ó 2013 by the Arthroscopy Association of North America 0749-8063/12656/$36.00 http://dx.doi.org/10.1016/j.arthro.2012.12.001
his findings.11-21 Recent studies have shown numerous benefits of the arthroscopic approach, including reduction in hospitalization time, as well as in pain, edema, complications, and expense, while simultaneously exhibiting faster time to recovery and fusion.21-27 However regardless of the surgical technique used, nonunion is a known potential complication with significant consequences. It can lead to continued pain, edema, and instability and may require additional or revision surgery, which adds to patient recovery time and increases health care expenses. Despite reports of nonunion being a potential consequence of ankle arthrodesis, irrespective of surgical approach used, the exact incidence of nonunion after arthroscopic ankle arthrodesis remains unknown. In an effort to determine the actual incidence of nonunion after arthroscopic ankle arthrodesis, we undertook a systematic review.
Methods The authors performed a systematic review of electronic databases and relevant peer-reviewed sources including OvidSP/MEDLINE (http://ovidsp.tx.ovid.com) and a general search engine (http://www.google.com). Additionally, we manually searched common American,
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 29, No 5 (May), 2013: pp 949-954
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Fig 1. (A) Arthroscopic image through standard anterolateral portal shows use of ring curette for debridement of remaining talar and tibial cartilaginous surfaces with exposure of subchondral bone plate. (B) Standard anteromedial portal view shows acromionizer debriding through subchondral bone plate down to appropriate level of raw bleeding bone. (C) Intraoperative image intensification through lateral view verifying acromionizer reaching posterior recess of ankle joint with noted retained internal fixation from previous ankle fracture. (D) Standard anterolateral view reveals angled gold-tipped chondral pick showing microfracture technique. (E) Standard anterolateral view reveals angled chondral pick with gold tip buried to proper level showing microfracture technique. (F) Standard anteromedial view shows ankle joint surfaces after debridement and microfracture technique, before deflating thigh tourniquet. (G) Standard anteromedial view shows ankle joint surfaces after debridement and microfracture technique, verifying raw bleeding substrate after deflation of thigh tourniquet. (H) Intraoperative image intensification of anteroposterior view of ankle after final positioning and placement of rigid internal fixation including large-fragment tripod screw construct (with noted retained medial malleolar fixation from previous ankle fracture). (I) Intraoperative image intensification of lateral view of ankle after final positioning and placement of rigid internal fixation (with noted retained medial malleolar fixation from previous ankle fracture).
British, and European orthopaedic and podiatric scientific literature for relevant articles. Only articles that included isolated ankle arthrodesis, greater than 20 ankles, minimum mean follow-up of 12-months, a 2-portal anterior arthroscopic approach, fixation with 2 or 3 largediameter cannulated cancellous screws, and a nonunion rate with no restrictions on cause were considered. We performed this systematic review between August 2011 and September 2012, with no restriction on date or language and used an inclusive text word query
“arthroscopic ankle arthrodesis” AND “nonunion” in which the uppercase words represent the Boolean operators used. All the articles were reviewed by each of us, and complete agreement was necessary for final inclusion, with the lead author (B.P.A.) being the moderator. Only full-text published articles were considered. For purposes of this review, all types of nonunion were examined, including that seen on radiography and in clinical practice, with delineation of symptomatic versus asymptomatic.
NONUNION AFTER ARTHROSCOPIC ANKLE ARTHRODESIS
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to range from less than 5%2,3,28,29 to 41%.6,30 With the advent of improved surgical techniques and advanced methods of fixation, the incidence of nonunion decreased, but the exact incidence for open approaches is not known. A recent meta-analysis comparing total ankle replacement and ankle arthrodesis found a nonunion rate of 10%, with 65% of revision procedures being performed to treat nonunions in patients with failed ankle arthrodeses.31 In our current systematic review, we found a lower incidence of nonunion (8.6%) using one fixation construct through a 2-portal arthroscopic approach. Apart from a lower incidence of nonunion, we found that the authors of the involved studies in this review repeatedly referenced additional benefits of an arthroscopic approach for isolated ankle arthrodesis, which were also noted in their respective results. Although these benefits are beyond the scope and focus of this article, they have been noted previously and include reduced time to union, shorter hospital stays, fewer complications, and decreased postoperative pain and edema.11-21 Furthermore, in regard to the current atmosphere in medical care and ongoing changes with reimbursement, there may be a fiduciary obligation for further research in this area. Specifically this would include a comparative cost analysis, patient satisfaction measurements, and investigation of overall complication rates between arthroscopic and open ankle arthrodesis procedures. These results may reveal further cost savings and improved patient care by using an arthroscopic approach.
Results The search for potentially eligible information for inclusion in the systematic review yielded a total of 27 articles. We obtained and reviewed all articles identified. We also completed an updated search for new articles in October 2012, which yielded no further studies. After considering all the potentially eligible articles, 7 (25.9%) met our inclusion criteria for the study (Fig 2).21-27 A total of 244 patients (148 [60.7%] male and 96 [39.3%] female patients) and 244 total ankles were included (Table 1). The weighted mean age of the patients was 49.2 years and the weighted mean follow-up of the studies that included the specific time of follow-up was 24.1 months. The incidence of nonunion was 8.6% (21 of 244). Fourteen of the nonunions (66.7%) were symptomatic and required further intervention. The methodologic quality of included studies was generally fair. For the studies involving arthroscopic ankle arthrodesis that met our inclusion criteria, all were full-text articles that were considered evidencebased medicine level IV studies. Furthermore, all were published in known peer-reviewed journals.
Discussion The purpose of this systematic review was to evaluate the overall incidence of nonunion after isolated arthroscopic ankle arthrodesis. Recently, the arthroscopic approach has been shown to offer numerous advantages over open or mini-open techniques. Nevertheless, nonunion remains a potential complication regardless of surgical method. To our knowledge, the overall incidence of nonunion after an isolated arthoscopic ankle arthrodesis has not been previously examined. Historically, nonunion rates after open ankle arthrodesis have been noted
Limitations Numerous weaknesses of this study were considered. First, we performed the search for articles that met
Potentially relevant articles after search in digital databases with each abstract reviewed for more information about study design or surgical procedure (n = 27)
Articles Excluded on Abstract Involved additional surgical procedures (n = 5)
Full-text articles retrieved for detailed comparison with inclusion criteria (n = 22)
Articles Excluded on Full Text Did not meet minimum number of ankles (n = 13) Used portal other than anteromedial or anterolateral (n = 1) Used fixation other than crossed screws (n = 1) Articles included in review (n = 7)
Fig 2. Flowchart of the articles during the selection process for this systematic review.
952 (4.8) (12.8) (5.2) (7.1) (15.5) (3.9) (12) (8.6) 1 5 3 3 4 1 4 21 34 (18-60) 12 (NA) for union; 20.4 (NA) for nonunion Minimum of 12 mo (NA) 27 (12-64) 18.3 (6-75) 36 (17-60) 22 (6-53) 24.1 (6-144) 8.9 (7-14) 6.7 (5.3-10) NA NA NA 10.5 (9-12) NA 8.4 (5.3-14) 95.2 87.2 94.8 92.9 84.6 96.1 88 91.4 (22-65) (40-89) (23-80) (19-75) (31-69) (26-81) (38-86) (19-89) 52.7 65 51 46 NA 52.2 66 49.2 21 39 58 42 26 26 32 244 (14/7) (14/25) (38/20) (26/16) (15/11) (18/8) (23/9) (148/96) NA, not available.
21 39 58 42 26 26 32 244 Zvijac et al.21 (2002) (IV) Collman et al.22 (2006) (IV) Nielsen et al.23 (2008) (IV) Crosby et al.24 (1996) (IV) Jerosch et al.25 (1996) (IV) Saragas26 (2004) (IV) Odutola et al.27 (2012) (IV) Total
Average Time to Union in Weeks (range) Ankle Arthrodesis Rate (%) Average Age in Years (range) Total No. of Ankles Total No. of Patients (M/F) Author (Year) (Level of Evidence)
Table 1. Statistical Description of the Studies That Met the Criteria for Inclusion in the Systematic Review
Average Follow-up in Months (range)
Total No. of Nonunions (%)
B. P. ABICHT AND T. S. ROUKIS
inclusion criteria through electronic databases. It is inherently possible that pertinent references may have been inadvertently overlooked or excluded. Moreover, the search did not include every potential electronic database and was restricted to only full-text articles. A more expansive search may have yielded supplementary articles for inclusion. In addition, the inclusion criteria were quite narrow. This produced a small subset of articles for evaluation. The fixation construct included was 2 or 3 large-diameter cannulated cancellous screws, which was by far the most common fixation construct noted throughout the literature. Patients who received a third screw may have subsequently gained a more rigid internal fixation construct, thereby influencing their risk of nonunion and altering a given article’s reported incidence of nonunion. Three versus 2 screws was not controlled for, but selecting either a 2-screw construct or a 3-screw construct would have eliminated many potential studies that were otherwise included in this review. Additionally, there was one study that involved fixation with 2 headless fully threaded cancellous screws, with the intention of obviating future screw removal secondary to prominent hardware.27 These authors were correct in their hypothesis because none of the 32 patients involved in their study required hardware removal for the duration of their published follow-up (mean follow-up of 22 months). Considering the significant options available for alternative fixation and accessory arthroscopic portals, we felt that a narrower search would better ensure critical analysis of the arthroscopic ankle arthrodesis procedure. Furthermore, the fixation construct used in our inclusion criteria is one that was noted throughout most of the potential articles reviewed. Second, the inclusion criteria eliminated studies that included adjunctive procedures with arthroscopic ankle arthrodesis, such as calcaneal osteotomy, subtalar joint arthrodesis, gastrocnemius lengthening, and so on. Excluding these studies32-34 eliminated 251 potential ankles and increased the incidence of nonunion from 7.5% to the current review’s result of 8.6%. The lower rate may be a more realistic value because adjunctive procedures are often necessary to provide patients with optimal outcomes, and sometimes these additional procedures are not anticipated until the surgeon and patient are in the intraoperative setting. Although studies that failed to involve only isolated ankle arthrodesis procedures were ultimately excluded in this review, surgeons should note that the incidence of nonunion may actually be less than the stated 8.6%, especially when indicated adjunctive procedures are performed. Third, we did not specifically examine the type and period of immobilization for the operative lower extremity in this review, nor were they involved in the inclusion criteria. However the postoperative care was not consistent throughout the included studies. In the
NONUNION AFTER ARTHROSCOPIC ANKLE ARTHRODESIS
majority of cases, patients were immobilized initially with a posterior splint and then transitioned to a short-leg cast at the first postoperative follow-up visit, in addition to being kept on a noneweight-bearing regimen for 4 to 6 weeks. One study did apply a partial weight-bearing walking cast as early as 1 week postoperatively.21 Some studies initially placed a below-knee back slab,21,26 whereas others added a U-splint22 or went straight to a complete cast23-25 for further immobilization. Furthermore, various studies used plaster, whereas others used fiberglass or did not specify what type of material was used. This variability in postoperative management may have an impact on the overall incidence of nonunion but remains a matter for conjecture. Finally, our inclusion criteria failed to address deformity. Historically, the arthroscopic approach has been reserved for end-stage ankle arthrosis for various causes with either no or minimal deformity, which is defined as less than 15 of ankle varus or valgus malalignment in the frontal plane. One study,32 which was excluded from our analysis, specifically analyzed the impact of preoperative ankle deformity, comparing 2 different cohorts treated with ankle arthrodesis through an arthroscopic approach. The first cohort in their study included patients with ankles with 15 or less varus or valgus deformity. The comparative group included patients with ankles with greater than 15 varus or valgus deformity, but no greater than 45 as measured on a standard anteroposterior weight-bearing radiograph. Both groups experienced high fusion rates and there was no statistically significant difference, with the authors stating that the arthroscopic approach may be used in cases of significant ankle deformity. A similar study,34 which was also excluded from our analysis, compared one group of patients with up to 15 varus/ valgus deformity and another group of patients with 15 degree deformity or greater that had similar findings. An overall fusion rate of 91% was noted, with a 94% fusion rate in the group with lesser deformity compared with 88% for the group with greater deformity. A third study,23 which was included in our review, pitted an arthroscopic ankle arthrodesis group of patients with minimal deformity (5 or less of varus/ valgus malalignment in the frontal plane) versus an open ankle arthrodesis group of patients with deformity (varus/valgus malalignment greater than 5 in the frontal plane). At 12 weeks there was a statistically significant difference in fusion ratesd90% in the arthroscopic group and only 57% in the open group. At 1 year the fusion rates remained greater for the arthroscopic group than for the open group, but this was not statistically significant, with fusion rates being 95% and 84%, respectively. One may infer that the arthroscopic approach requires less time to achieve union than does the open approach, but the degree of deformity was not equal across cohorts. A fourth
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study,33 which was excluded from our analysis, did not control for ankle deformity, including 118 arthroscopic ankle arthrodesis procedures with preoperative deformity ranging from 22 valgus to 28 varus. Their incidence of nonunion was 7.6%, which is noted to be less than the results of this review (8.6%). Ultimately, the dynamics of adjunctive surgical procedures, alternative fixation constructs, postoperative immobilization preference, and degree of preoperative ankle deformity may impart significant influence on the overall incidence of nonunion associated with the arthroscopic ankle arthrodesis procedure. Future prospective studies are required to further investigate their influence on nonunion rates in arthroscopic ankle arthrodesis. Once this is identified, the incidence of nonunion may decrease further. Combining a low nonunion rate with the aforementioned benefits inherent in an arthroscopic approach, the safety and efficacy may prove superior to the traditional open approach.
Conclusions We performed a systematic review using electronic databases to determine the actual incidence of nonunion after arthroscopic ankle arthrodesis. Based on the inclusion criteria, a total of 7 studies were included in the analysis. The methodologic design of the studies was fair. Compared with published nonunion rates after traditional open techniques, the results of these studies reveal a relatively low incidence of nonunion of 8.6% (21 of 244) after isolated arthroscopic ankle arthrodesis using a standard anterior 2-portal technique with fixation using 2 or 3 large-diameter cancellous screws. However given the limited data available for review, additional prospective investigations are necessary. Furthermore, direct comparative studies on ankle arthrodesis procedures through open, mini-open, and arthroscopic approaches are warranted to further delineate the differences in nonunion rates and reveal potential supplemental benefits as described previously.
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