581450

research-article2015

FAIXXX10.1177/1071100715581450Foot & Ankle InternationalPapadelis et al

Article

Isolated Subtalar Distraction Arthrodesis Using Porous Tantalum: A Pilot Study

Foot & Ankle International® 1­–5 © The Author(s) 2015 Reprints and permissions: sagepub.com/journalsPermissions.nav DOI: 10.1177/1071100715581450 fai.sagepub.com

Eustratios A. Papadelis, MD, PhD1, Panagiotis K. Karampinas, MSc, MD, PhD1, Eustratios Kavroudakis, MSc, MD1, John Vlamis, MD, PhD1, Vasilios D. Polizois, MD, PhD1, and Spiros G. Pneumaticos, MD, PhD1

Abstract Background: During reconstructive procedures of the hindfoot, a structural graft is often needed to fill gaps. To eliminate donor site morbidity and limited availability of autografts, porous tantalum was used. Methods: Eighteen patients who underwent subtalar joint distraction arthrodesis by means of trabecular metal augment were reviewed retrospectively. The results were evaluated clinically, with the American Orthopaedic Foot & Ankle Society (AOFAS) score and the visual analog scale (VAS) for pain, and were assessed radiologically. The mean follow-up period was 18 months. Results: Computed tomography showed sound fusion. There was a marked increase in AOFAS scores and a decrease in VAS scores. Arthrodesis was achieved in all cases with no major postoperative complications. Radiographically, there was a marked increase in all measured parameters (talocalcaneal angle, talocalcaneal height, talar declination angle), and the intraoperatively achieved correction was maintained at the last follow-up visit. Conclusion: Our data suggest that porous tantalum may be used as a structural graft option for subtalar arthrodesis. Level of Evidence: Level IV, retrospective case series. Keywords: subtalar arthrodesis, porous tantalum Subtalar bone block arthrodesis is a valuable treatment for various isolated subtalar disorders such as symptomatic primary subtalar arthritis, posttraumatic arthritis (especially after calcaneal fractures due to posterior facet join depression), and nonunion or malunion of attempted subtalar arthrodesis. However, the procedure may result in great functional impairment and may cause altered pressure and force distribution under both feet.11 Structural autograft from iliac crest is considered the gold standard but is associated with donor site morbidity in up to 41% of cases,33 large hematomas in 9.6% and wound dehiscence in 2.7%,31 and limited quantity of grafts and risk of graft collapse.20 Allograft has the risk of infectious disease transmission and failure to integrate.4 Porous tantalum is a trabecular metal that has been used extensively in revision of total hip and total knee arthroplasties for reconstruction of large bony defects,11,16,22,26,29,35,37 in spinal fusions,14 in cranioplasty plates, and in pacemaker electrodes.25 Its use in foot and ankle treatment is new.4,17 Tantalum is a biocompatible material with mechanical properties similar to those of trabecular bone. Its modulus of elasticity is 50 times that of bone, it has high strength and ductility, and it has intrinsically high

friction and stability, enabling osteoconduction and fixation.2,3,34,39 Sufficient bone ingrowth has been shown both in animal studies and in human specimens.9,13 These properties allow tantalum to serve as a scaffold in the setting of arthrodesis.28,38 The aim of our pilot study was to evaluate clinical outcomes and analyze midterm results of subtalar distraction arthrodesis with tantalum. Our method was designed to address the problems of nonunion and donor site morbidity that are frequently encountered with the use of structural autograft and to avoid the loss of the initial talocalcaneal height, achieved intraoperatively, that sometimes is observed with the other methods of subtalar joint arthrodesis.6,7,30,36

1

Third Department of Orthopaedics, University of Athens Medical School, KAT Hospital, Athens, Greece Corresponding Author: Panagiotis K. Karampinas, MSc, MD, PhD, University of Athens Medical School, III Orthopaedic Department, KAT Hospital, 2 Nikis Str, 14561, Kifissia, Athens, Greece. Email: [email protected]

Downloaded from fai.sagepub.com at FLORIDA STATE UNIV LIBRARY on September 28, 2015

2

Foot & Ankle International 

Methods We retrospectively reviewed 18 patients who had posttraumatic subtalar joint arthritis after calcaneal fracture or primary subtalar arthritis and who underwent subtalar distraction arthrodesis between May 2008 and April 2012. All patients had severe subtalar pain, loss of the longitudinal arch, and loss of calcaneal height. All patients had failed nonoperative treatment, which consisted of modification of activities, use of an orthosis, and physical therapy. The group consisted of 11 men and 7 women with a mean age 42.6 years (range, 36-48 years). Patients provided informed consent, and the study was approved by the institutional review board of KAT-EKA Trauma Hospital of Athens. Each patient’s height, weight, activity level, occupation, history of illness, and smoking status were determined. A standard preoperative clinical assessment was performed, and the American Orthopaedic Foot & Ankle Society (AOFAS) hindfoot score was documented preoperatively and at the last follow-up visit. Of the possible 100 points on the hindfoot score, the maximum possible for a patient with subtalar arthrodesis is 94 due to loss of subtalar movement. Dorsiflexion and plantar flexion of the ankle were measured with a goniometer, alignment of the hindfoot was assessed from posterior view, and gait was observed to assess limp. Pain was evaluated with a visual analog scale (VAS) during full weight bearing and ambulation. Radiological analysis was based on lateral and Broden views taken before surgery, immediately after surgery, and at the last follow-up visit.5 The fusion rate and the achievement of arthrodesis were based on radiological, clinical, and computed tomography (CT) findings. The talocalcaneal angle was measured by drawing a line representing the long axis of the talus and its intersection with the longitudinal axis of the calcaneus.1 The talar declination angle, which is formed by the axis of the talus to the plane of support, and the talocalcaneal height, measured from the dome of the talus to the base of the calcaneus, were also assessed.

Operative Technique All the operations were performed by the same senior surgeon, with the same surgical approach and the same implants. The procedure was performed with the patient in the prone position. A longitudinal posterolateral incision was made to allow closure without tension after distraction, the sural nerve was identified, and its main trunk and branches were protected. The peroneal tendons were protected. Lateral wall decompression was then performed with an osteotome.21 The subtalar joint was exposed, and visualization was improved with the use of a lamina spreader. The residual cartilage was denuded from the subtalar joint with an osteotome, and the surfaces were assessed

Figure 1.  Last follow-up ankle radiograph demonstrating subtalar fusion with porous tantalum.

for adequate vascularity. The subchondral surfaces were then fish-scaled to increase the surface area. The lamina spreader, when used, was left in place for provisional distraction. Intraoperative fluoroscopy was used to ensure that adequate distraction had been achieved. A tantalum block, a trabecular metal augment (Zimmer; Warsaw, IN), was contoured intraoperatively to match the appropriate height and was wedged into the subtalar joint as the lamina spreader was removed. The size of the block was determined by the amount of distraction required to correct the talar inclination angle and by the amount of the removed bone. Intraoperative fluoroscopy was used to confirm that the block was in a satisfactory position and that the proper position of the talus and adequate correction had been achieved. Postoperatively, all patients wore a cast and were non-weight-bearing using crutches. The sutures were removed after 2 weeks, the cast was exchanged at 6 weeks, and patients were allowed touch weight bearing. At 12 weeks, the cast was removed, radiographs were taken, and the patient was allowed weight bearing as tolerated. The patients were evaluated both clinically and radiographically at regular 4-week intervals until we judged the presence of union (Figure 1). Clinical criteria for fusion were clinical stability and lack of clinical symptoms with stress applied to the former subtalar joint. Radiographic criteria for fusion were signs of bony incorporation of the tantalum and absence of zones or gaps in the bone block of the tantalum interface. The treating surgeon and the hospital radiologist independently determined the occurrence of fusion clinically and radiographically. If the fusion had not been verified (9 patients), a CT scan was performed to show signs of bony incorporation of the tantalum, evidence of trabecular interdigitation, and absence of radiolucency (Figure 2). At the final follow-up, the AOFAS score was determined23 and clinical outcome complications were assessed.

Downloaded from fai.sagepub.com at FLORIDA STATE UNIV LIBRARY on September 28, 2015

3

Papadelis et al

Despite the fact that 1 patient had to quit hiking and 2 patients quit bicycling, all of them returned to their previous occupations. All patients reported that they were satisfied with the results and they would recommend this procedure to anyone having the same problem. There was no dehiscence, infection, or other skin complication.

Radiographic Results Preoperative and follow-up radiographs were available for 18 patients. The mean talocalcaneal angle increased from 21.6 degrees (range, 5-34 degrees) to 29.16 degrees (range, 10-40 degrees). The mean talar declination angle increased from 5.8 degrees (range, –10 to 21 degrees) to 24.1 degrees (range, 13-33 degrees). The talocalcaneal height increased from an average of 63.7 degrees (range, 52-76 degrees) to an average of 71.8 degrees (range, 63-80 degrees). This increase was maintained even at the last follow-up visit after complete weight bearing had been allowed for at least 4 weeks. Statistical analysis showed significant differences between the preoperative and follow-up findings in the talocalcaneal height and talocalcaneal and talar declination angles (P < .001). CT scanning was performed in suspected cases of delayed or nonunion (9 patients) according to the treating surgeon’s and independent radiologist’s instructions. The CT scans all showed signs of bone incorporation of the tantalum, evidence of trabecular interdigitation into the device, and absence of radiolucency. Figure 2.  Last follow-up computed tomography scan presenting evidence of trabecular interdigitation into the material, absence of radiolucency, and signs of bone incorporation of the tantalum.

Results At the final follow-up (mean final follow-up 17.7 months; range, 17.21-18.13 months), all 18 arthrodeses were fused. We observed no infection, no lateral impingement, no malalignment of the hindfoot (defined as more than 10 degrees of valgus or more than 5 degrees of varus relative to anatomical alignment), no prominent hardware, and no sural neuralgia.

Clinical Outcome The AOFAS hindfoot score (maximum 94 points) increased from a mean preoperative value of 41.3 (from 23 to 58) to a mean postoperative value of 71.5 (from 67 to 76). There was a marked decrease in VAS pain scores, from a mean preoperative value of 8.6 (from 7 to 10) to a postoperative 2.4 (from 0 to 4). All of the above changes were statistically significant (P < .0001). Most of our patients (15/18) were able to assume everyday activities without serious limitations.

Discussion Symptomatic subtalar arthritis, primary or after intra-articular calcaneal fractures, can be treated by subtalar arthrodesis in situ.8,10,15,27,32 However, in deformities that involve collapse of the subtalar joint, in situ subtalar arthrodesis cannot restore height. Bone block distraction arthrodesis has been used when there is a decrease in talar inclination. Distraction under the body of the talus can restore a nearanatomical talar inclination.18 Carr et al6 introduced subtalar bone block distraction arthrodesis to restore satisfactory orientation of the hindfoot in an attempt to improve function. The concept was that substantial loss of heel height may lead to symptomatic anterior tibiotalar impingement, and the investigators recommended that this deformity be corrected. Today, the use of autograft (iliac crest graft) is considered to be the gold standard for distraction arthrodesis. Although it has a low cost and an excellent osteoinductive potential, it is associated with donor site morbidity in up to 48% of cases, whereas the alternative, allograft, carries the risk of disease transmission and collapse. Fitzgibbons et al13 advocated the use of concentrated osteoprogenitor cells from bone marrow aspirate in combination with allograft preparations. The resultant product is able to promote

Downloaded from fai.sagepub.com at FLORIDA STATE UNIV LIBRARY on September 28, 2015

4

Foot & Ankle International 

osteoconduction, osteoinduction, and osteogenesis with limited morbidity but with an increase in the overall cost due to the use of selective retention systems.13 Emerging techniques have enabled the development of a seemingly unlimited supply of alternative bone graft materials with osteoconductive properties.18 In hip surgery, the use of tantalum augments has virtually eliminated the need for bulk allografts in the revision of acetabulum.24 In hindfoot surgery, tantalum has mainly been used in salvage procedures after failure of ankle arthroplasty in combination with intramedullary nails to fill large bone defects.17 A problem that is frequently encountered with the aforementioned methods of subtalar arthrodesis is a relatively small loss of the initial correction of talocalcaneal height with time, as the graft settles into the fusion site.6,7,30,36 Nonunion is another possible complication of arthrodesis that has been attributed mainly to avascular necrosis and smoking.12 To avoid donor site morbidity, risk of disease transmission, and nonunion but at the same time achieve a rapid and stable arthrodesis, we decided to implant trabecular metal (tantalum) in the subtalar joint. We observed no loss of deformity correction and no complications. This is consistent with the observations of Frigg et al,17 who were able to verify rapid bone ingrowth to the trabecular metal by means of micro-CT. The amount of foreign material needed to position inside the joint was minimal, thus minimizing the danger of future infection and severe bone loss in case of revision surgery. In current literature there is some concern as to the rate of union after bone block distraction arthrodesis. With an interpositional bone graft, 2 interfaces must unite, and most, but not all, studies have shown a rate of union close to 100%.5,6,30,34 Our results with the use of porous tantalum were similar as all of our patients achieved a sound fusion. Our results are in accordance with those of previous reports concerning functional outcome30,34; the mean AOFAS hindfoot score was significantly improved from 41.3 points preoperatively to 71.5 points at a mean final follow-up of 17.7 months (range, 17.21-18.13). Pain was significantly decreased, and the overall patient satisfaction was good. Henricson and Rydhom19 were also able to avoid loss of initial correction in salvage arthrodesis after failed ankle arthroplasty with a greater amount of hardware. Chan and Alexander7 found a mean loss of 4.7 mm in heel height from the time of surgery to final follow-up. This loss was seen when a single tricortical graft of the iliac crest was used. Trnka et al36 reported that the mean loss with a singlegraft technique was 1.0 mm. Carr et al6 noted loss of heel height in 2 patients, both of whom lacked internal fixation with which to secure the bone block. Our pilot study has certain limitations. First, our group of patients was small and our results, although they look

promising, cannot be considered absolutely safe. Second, the imaging of tantalum by CT was associated with artifacts that made precise assessment of bone ingrowth problematic. Third, we do not know the long-term outcome. Larger and comparative clinical trials are needed to document the efficacy of our method by comparing it with the use of autogenous iliac crest structural bone graft. Assessment of the microanatomy with histological studies and mechanical tests is warranted to ascertain the potential of porous tantalum for isolated subtalar distraction arthrodesis.

Conclusion The use of a trabecular metal augment (tantalum) when bone block arthrodesis was indicated had a low complication rate and was able to achieve a stable arthrodesis of the subtalar joint. The initial deformity correction was maintained, and the functional outcome was satisfactory. 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. Aronson J, Nunley J, Frankovitch K. Lateral talocalcaneal angle in assessment of subtalar valgus: follow-up of seventy Grice-Green arthrodeses. Foot Ankle. 1983;4(2):56-63. 2. Bobyn JD, Stackpool GJ, Hacking SA, Tanzer M, Krygier JJ. Characteristics of bone ingrowth and interface mechanics of a new porous tantalum biomaterial. J Bone Joint Surg Br. 1999;81(5):907-914. 3. Bobyn JD, Toh KK, Hacking SA, Tanzer M, Krygier JJ. Tissue response to porous tantalum acetabular cups: a canine model. J Arthroplasty. 1999;14(3):347-354. 4. Bouchard M, Barker LG, Claridge RJ. Technique tip: tantalum: a structural bone graft option for foot and ankle surgery. Foot Ankle Int. 2004;25(1):39-42. 5. Buch BD, Myerson MS, Miller SD. Primary subtalar arthrodesis for the treatment of comminuted calcaneal fractures. Foot Ankle Int. 1996;17(2):61-70. 6. Carr JB, Hansen ST, Benirschke SK. Subtalar distraction bone block fusion for late complications of os calcis fractures. Foot Ankle. 1988;9(2):81-86. 7. Chan SC, Alexander IJ. Subtalar arthrodesis with interposition tricortical iliac crest graft for late pain and deformity after calcaneus fracture. Foot Ankle Int. 1997;18(10):613-615. 8. Chandler JT, Bonar SK, Anderson RB, Davis WH. Results of in situ subtalar arthrodesis for late sequelae of calcaneus fractures. Foot Ankle Int. 1999;20(1):18-24.

Downloaded from fai.sagepub.com at FLORIDA STATE UNIV LIBRARY on September 28, 2015

5

Papadelis et al 9. D’Angelo F, Murena L, Campagnolo M, Zatti G, Cherubino P. Analysis of bone ingrowth on a tantalum cup. Indian J Orthop. 2008;42(3):275-278. 10. Dahm DL, Kitaoka HB. Subtalar arthrodesis with internal compression for post-traumatic arthritis. J Bone Joint Surg Br. 1998;80(1):134-138. 11. Diezi C, Favre P, Vienne P. Primary isolated subtalar arthrodesis: outcome after 2 to 5 years follow-up. Foot Ankle Int. 2008;29(12):1195-1202. 12. Easley ME, Trnka HJ, Schon LC, Myerson MS. Isolated subtalar arthrodesis. J Bone Joint Surg Am. 2000;82(5):613-624. 13. Fitzgibbons TC, Hawks MA, McMullen ST, Inda DJ. Bone grafting in surgery about the foot and ankle: indications and techniques. J Am Acad Orthop Surg. 2011;19(2):112-120. 14. Fernández-Fairen M, Sala P, Dufoo M Jr, Ballester J, Murcia A, Merzthal L. Anterior cervical fusion with tantalum implant: a prospective randomized controlled study. Spine (Phila Pa 1976). 2008;33(5):465-472. 15. Flemister AS Jr, Infante AF, Sanders RW, Walling AK. Subtalar arthrodesis for complications of intra-articular calcaneal fractures. Foot Ankle Int. 2000;21(5):392-399. 16. Flecher X, Paprosky W, Grillo JC, Aubaniac JM, Argenson JN. Do tantalum components provide adequate primary fixation in all acetabular revisions? Orthop Traumatol Surg Res. 2010;96(3):235-241. 17. Frigg A, Dougall H, Boyd S, Nigg B. Can porous tantalum be used to achieve ankle and subtalar arthrodesis? A pilot study. Clin Orthop Relat Res. 2010;468(1):209-216. 18. Haddad SL, Coetzee JC, 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(9):1899-1905. 19. Henricson A, Rydholm U. Use of a trabecular metal implant in ankle arthrodesis after failed total ankle replacement. Acta Orthop. 2010;81(6):745-747. 20. Jäger M, Westhoff B, Wild A, Krauspe R. Bone harvesting from the iliac crest. Orthopade. 2005;34(10):976-982, 984, 986-990, 992-994. 21. Johansson JE, Harrison J, Greenwood FA. Subtalar arthrodesis for adult traumatic arthritis. Foot Ankle. 1982;2(5):294298. 22. Kim WY, Greidanus NV, Duncan CP, Masri BA, Garbuz DS. Porous tantalum uncemented acetabular shells in revision total hip replacement: two to four year clinical and radiographic results. Hip Int. 2008;18(1):17-22. 23. Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M. Clinical rating systems for the anklehindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int. 1994;15(7):349-353. 24. Lachiewicz PF, Soileau ES. Tantalum components in difficult acetabular revisions. Clin Orthop Relat Res, 2010;468(2):454-458.

25. Levine B, Sporer S, Della Valle CJ, Jacobs JJ, Paprosky W. Porous tantalum in reconstructive surgery of the knee: a review. J Knee Surg. 2007;20(3):185-194. 26. Levine BR, Sporer S, Poggie RA, Della Valle CJ, Jacobs JJ. Experimental and clinical performance of porous tantalum in orthopedic surgery. Biomaterials. 2006;27(27):4671-4681. 27. Mann RA, Beaman CN, Horton GA. Isolated subtalar arthrodesis. Foot Ankle Int. 1998;19(8):511-519. 28. Matsuno H, Yokoyama A, Watari F, Uo M, Kawasaki T. Biocompatibility and osteogenesis of refractory metal implants, titanium, hafnium, niobium, tantalum and rhenium. Biomaterials. 2001;22(11):1253-1262. 29. Meneghini RM, Lewallen DG, Hanssen AD. Use of porous tantalum metaphyseal cones for severe tibial bone loss during revision total knee replacement. J Bone Joint Surg Am. 2008;90(1):78-84. 30. Myerson M, Quill GE Jr. Late complications of fractures of the calcaneus. J Bone Joint Surg Am. 1993;75(3):331-341. 31. Niedhart C, Pingsmann A, Jürgens C, Marr A, Blatt R, Niethard FU. Complications after harvesting of autologous bone from the ventral and dorsal iliac crest—a prospective, controlled study. Z Orthop Ihre Grenzgeb. 2003;141(4): 481-486. 32. Russotti GM, Cass JR, Johnson KA. Isolated talocalcaneal arthrodesis: a technique using moldable bone graft. J Bone Joint Surg Am. 1988;70(10):1472-1478. 33. Sasso RC, LeHuec JC, Shaffrey C; Spine Interbody Research Group. Iliac crest bone graft donor site pain after anterior lumbar interbody fusion: a prospective patient satisfaction outcome assessment. J Spinal Disord Tech. 2005;18(suppl):S77-S81. 34. Shimko DA, Shimko VF, Sander EA, Dickson KF, Nauman EA. Effect of porosity on the fluid flow characteristics and mechanical properties of tantalum scaffolds. J Biomed Mater Res B Appl Biomater. 2005;73(2):315-324. 35. Stiehl JB. Trabecular metal in hip reconstructive surgery. Orthopedics. 2005;28(7):662-670. 36. Trnka HJ, Easley ME, Lam PW, Anderson CD, Schon LC, Myerson MS. Subtalar distraction bone block arthrodesis. J Bone Joint Surg Br. 2001;83(6):849-854. 37. Unger AS, Lewis RJ, Gruen T. Evaluation of a porous tantalum uncemented acetabular cup in revision total hip arthroplasty: clinical and radiological results of 60 hips. J Arthroplasty. 2005;20(8):1002-1009. 38. Zardiackas LD, Parsell DE, Dillon LD, Mitchell DW, Nunnery LA, Poggie R. Structure, metallurgy, and mechanical properties of a porous tantalum foam. J Biomed Mater Res. 2001;58(2):180-187. 39. Zhang Y, Li L, Shi ZJ, Wang J, Li ZH. Porous tantalum rod implant is an effective and safe choice for early-stage femoral head necrosis: a meta-analysis of clinical trials. Eur J Orthop Surg Traumatol. 2013;23(2):211-217.

Downloaded from fai.sagepub.com at FLORIDA STATE UNIV LIBRARY on September 28, 2015

Isolated Subtalar Distraction Arthrodesis Using Porous Tantalum: A Pilot Study.

During reconstructive procedures of the hindfoot, a structural graft is often needed to fill gaps. To eliminate donor site morbidity and limited avail...
319KB Sizes 2 Downloads 10 Views