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Electrothermal Collagen Shrinkage
IN BRIEF
Electrothermal Collagen Shrinkage Pedro K. Beredjiklian, MD, Michael Rivlin, MD
BASIC SCIENCE Radiofrequency thermal probes use alternating current at high frequency. This creates a current, or flow of electrons, and ionic agitation that leads to frictional forces in which energy is lost to the surrounding tissues in the form of heat.4 At 60°C, tissue contraction is noted due to coagulation; however, when temperatures exceed 100°C, tissue vaporizes and ablation occurs.5,6 The constituents that are mainly responsible for the physical structure and properties of ligaments are made up of collagen. At 65°C, collagen undergoes structural changes as the triple helix unwinds and denaturation begins. Fibril diameter increases, and fibril size variation decreases; at these temperatures, cross-striations are lost.3 As the contracted collagen mass loses its microscopic fiber organization, its physical properties change, and the tissue becomes increasingly stiff. In vitro, bovine knee capsule begins to shrink7 at 60°C, From the Department of Orthopaedic Surgery, Jefferson Medical College, Philadelphia, PA; Hand Surgery Division, The Rothman Institute, Philadelphia, PA. Received for publication December 20, 2011; accepted in revised form March 5, 2012. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Pedro K. Beredjiklian, MD, Jefferson Medical College, Department of Orthopaedic Surgery, The Rothman Institute, Division of Hand Surgery, 925 Chestnut Street, Philadelphia, PA 19107. 0363-5023/12/37A10-0036$36.00/0 doi:10.1016/j.jhsa.2012.03.011
with maximum shrinkage of near 50% occurring above 65°C. By using these methods, capsular tissue can be shrunk without detrimental effects to its viscoelastic properties.8 In biomedical studies on rabbit joint capsule tissue treated with thermal energy, there was no difference in ultimate stress, yield stress, elastic modulus, or load-to-failure when it was compared with nontreated tissues.9 Collagen shrinkage is followed by fibroblastic nuclear pyknosis, which becomes apparent shortly following the thermal insult. In an experiment on sheep capsule, Hayashi et al demonstrated changes on the cellular level.10 Fibroblasts begin laying down collagen to repair the tissues, using the large denatured collagen fibrils as scaffolding. After the initial necrosis and hyalinization, tissue repair begins with fibroblast activation and capillary sprouting in the affected tissue. By 90 to 180 days, the area appears normal or as slightly hypercellular native tissue. ELECTROTHERMAL COLLAGEN SHRINKAGE IN SHOULDER AND KNEE SURGERY Arthroscopic procedures have improved surgical recovery and decreased postoperative discomfort compared to traditional open procedures. As the initial impetus for the implementation of electrothermal collagen shrinkage (ECS) in shoulder surgery, it was believed that arthroscopic thermal capsulorrhaphy could lead to a reduction in the need for open stabilization procedures. As such, it would be used as an adjunct to open or arthroscopic capsule–labral repairs.6 Gartsman and colleagues11 performed thermal capsulorrhaphy on patients with anterior–inferior glenohumeral instability to complement Bankart lesion repairs, with 92% good to excellent results. This initial enthusiasm waned after longer-term follow-up was evaluated. D’Alessandro and colleagues12 performed a nonrandomized prospective study evaluating the results of thermal capsulorrhaphy in 84 patients, with an average follow-up of 38 months. Using the American Shoulder and Elbow Surgeons shoulder assessment score, they found unsatisfactory outcomes in 31 patients (37%). In addition, complications including attenuation of capsular tissue, axillary nerve injury, and chondrolysis have been reported, further raising concern about ECS.13
© ASSH 䉬 Published by Elsevier, Inc. All rights reserved. 䉬 2165
In Brief
HISTORY The application of heat for coagulation and ablation of human tissues has traditionally posed an appealing method of treating a variety of pathologic conditions. In ophthalmology, the alteration of corneal curvature by means of thermal energy to correct various disorders affecting vision1 dates back to the 1960s. In cardiac surgery, electrochemical ablators have been used to disrupt abnormal conductive properties of cardiac tissues in patients with electrophysiological conductive alterations.2 After their introduction in cardiac surgery, electrothermal probes gained preference as a means to deliver heat to tissues because of their lower operating costs, safer use, ease of maneuverability, and accuracy.
2166
ELECTROTHERMAL COLLAGEN SHRINKAGE
Electrothermal collagen shrinkage in larger joints such as the knee was similarly met with initial interest followed by disappointment.14 When thermal shrinkage was performed on native and stretched graft anterior cruciate ligaments, results showed 79% failure rate for grafts and 38% failure rate for native ligaments.15 As a result, ECS as an adjunct to arthroscopic shoulder and knee surgery has been largely abandoned.
In Brief
ELECTROTHERMAL COLLAGEN SHRINKAGE IN HAND SURGERY In contrast, ECS has been used with some success in hand surgery, specifically as it relates to treatment of partial or “stretch” injuries of the scapholunate interosseous ligament. Hirsh and colleagues16 reported on 10 patients with structural disruption of the scapholunate interosseous ligament (Geissler type 2 injuries) treated with monopolar ECS of the scapholunate interosseous ligament. At minimum 12 months of followup, 9 patients (90%) were asymptomatic and had returned to their preinjury functional level. One patient developed recurrent symptoms 7 months after surgery and required revision surgery. In a similar study, Shih et al17 reported on 19 patients with static and dynamic scapholunate instability using monopolar ECS. They reported a 79% success rate at a minimum 24-month follow-up. Darlis et al18 reported on 16 patients with partial tears of the scapholunate interosseous ligament treated with ECS. Using the modified Mayo wrist score, they tabulated 14 excellent or good results, 1 fair result, and 1 poor result. No complications were described. In most of these studies, the postoperative course included immobilization in a splint for 6 to 8 weeks after surgery, followed by a course of physical therapy. Other uses in hand surgery have included debridement of triangular fibrocartilage complex tears, treatment of capsular laxity of the thumb carpometacarpal joint after hemitrapeziectomy,19 and treatment of midcarpal instability.20 The results in the literature evaluating the outcomes of ECS in hand surgery should be taken with great caution. This is true in light of the fact that the available data originate from a handful of studies with low levels of evidence, and especially given the experience of this modality in knee and shoulder surgery. Although it is possible that ECS might fall into disfavor, several important differences between the hand and wrist and the other anatomic areas might make this a successful modality in hand surgery. First, the hand and wrist can tolerate prolonged postoperative immobilization well, in contrast with the knee or shoulder. It is possible that the immobilization might allow the tissues to retain the increased stiffness following
the shrinkage and, therefore, decrease the rate of recurrence of laxity. Second, the smaller size of the structures and the lower levels of mechanical stresses might lead to a more favorable mechanical environment for tissues after ECS, although there is no evidence in the literature to support this assertion. Despite these theoretical advantages, it is clear that additional studies are needed to better understand the role, safety, and efficacy of this treatment modality in disorders of the hand and wrist. REFERENCES 1. Stringer H, Parr J. Shrinkage temperature of eye collagen. Nature 1964;204:1307. 2. An HL, Saksena S, Janssen M, Osypka P. Radiofrequency ablation of ventricular myocardium using active fixation and passive contact catheter delivery systems. Am Heart J 1989;118:69 –77. 3. Lopez MJ, Hayashi K, Fanton GS, Thabit G III, Markel MD. The effect of radiofrequency energy on the ultrastructure of joint capsular collagen. Arthroscopy 1998;14:495–501. 4. Van Haesendonck C, Sinnaeve A, Willems R, Vandenbulcke F, Stroobandt R. Biophysical and electrical aspects of radiofrequency catheter ablation. Acta Cardiol 1995;50:105–115. 5. Wallace AL, Hollinshead RM, Frank CB. The scientific basis of thermal capsular shrinkage. J Shoulder Elbow Surg 2000;9:354 –360. 6. Medvecky MJ, Ong BC, Rokito AS, Sherman OH. Thermal capsular shrinkage: Basic science and clinical applications. Arthroscopy 2001;17:624 – 635. 7. Naseef GS III, Foster TE, Trauner K, Solhpour S, Anderson RR, Zarins B. The thermal properties of bovine joint capsule. The basic science of laser- and radiofrequency-induced capsular shrinkage. Am J Sports Med 1997;25:670 – 674. 8. Hayashi K, Markel MD, Thabit G III, Bogdanske JJ, Thielke RJ. The effect of nonablative laser energy on joint capsular properties. An in vitro mechanical study using a rabbit model. Am J Sports Med 1995;23:482– 487. 9. Selecky MT, Vangsness CT Jr, Liao WL, Saadat V, Hedman TP. The effects of laser-induced collagen shortening on the biomechanical properties of the inferior glenohumeral ligament complex. Am J Sports Med 1999;27:168 –172. 10. Hayashi K, Nieckarz JA, Thabit GIII, Bogdanske JJ, Cooley AJ, Markel MD. Effect of nonablative laser energy on the joint capsule: an in vivo rabbit study using a holmium:YAG laser. Lasers Surg Med 1997;20:164 –171. 11. Gartsman GM, Roddey TS, Hammerman SM. Arthroscopic treatment of anterior-inferior glenohumeral instability. Two to five-year follow-up. J Bone Joint Surg 2000;82A:991–1003. 12. D’Alessandro DF, Bradley JP, Fleischli JE, Connor PM. Prospective evaluation of thermal capsulorrhaphy for shoulder instability: indications and results, two- to five-year follow-up. Am J Sports Med 2004;32:21–33. 13. Levine WN, Bigliani LU, Ahmad CS. Thermal capsulorrhaphy. Orthopedics 2004;27:823– 826. 14. Zheng N, Davis BR, Andrews JR. The effects of thermal capsulorrhaphy of medial parapatellar capsule on patellar lateral displacement. J Orthop Surg Res 2008;3:45. 15. Smith DB, Carter TR, Johnson DH. High failure rate for electrothermal shrinkage of the lax anterior cruciate ligament: a multicenter follow-up past 2 years. Arthroscopy 2008;24:637– 641. 16. Hirsh L, Sodha S, Bozentka D, Monaghan B, Steinberg D, Beredjiklian PK. Arthroscopic electrothermal collagen shrinkage for symptomatic laxity of the scapholunate interosseous ligament. J Hand Surg 2005;30B:643– 647.
JHS 䉬 Vol A, October
ELECTROTHERMAL COLLAGEN SHRINKAGE
carpometacarpal arthritis treated with arthroscopic hemitrapeziectomy and thermal capsular modification without interposition. J Hand Surg 2010;35A:566 –571. 20. Mason WT, Hargreaves DG. Arthroscopic thermal capsulorrhaphy for palmar midcarpal instability. J Hand Surg 2007;32E: 411– 416.
In Brief
17. Shih JT, Lee HM. Monopolar radiofrequency electrothermal shrinkage of the scapholunate ligament. Arthroscopy 2006;22:553–557. 18. Darlis NA, Weiser RW, Sotereanos DG. Partial scapholunate ligament injuries treated with arthroscopic debridement and thermal shrinkage. J Hand Surg 2005;30A:908 –914. 19. Edwards SG, Ramsey PN. Prospective outcomes of stage III thumb
2167
JHS 䉬 Vol A, October
Electrothermal Collagen Shrinkage Pedro K. Beredjiklian, MD, Michael Rivlin, MD
BASIC SCIENCE Radiofrequency thermal probes use alternating current at high frequency. This creates a current, or flow of electrons, and ionic agitation that leads to frictional forces in which energy is lost to the surrounding tissues in the form of heat.4 At 60°C, tissue contraction is noted due to coagulation; however, when temperatures exceed 100°C, tissue vaporizes and ablation occurs.5,6 The constituents that are mainly responsible for the physical structure and properties of ligaments are made up of collagen. At 65°C, collagen undergoes structural changes as the triple helix unwinds and denaturation begins. Fibril diameter increases, and fibril size variation decreases; at these temperatures, cross-striations are lost.3 As the contracted collagen mass loses its microscopic fiber organization, its physical properties change, and the tissue becomes increasingly stiff. In vitro, bovine knee capsule begins to shrink7 at 60°C, From the Department of Orthopaedic Surgery, Jefferson Medical College, Philadelphia, PA; Hand Surgery Division, The Rothman Institute, Philadelphia, PA. Received for publication December 20, 2011; accepted in revised form March 5, 2012. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Pedro K. Beredjiklian, MD, Jefferson Medical College, Department of Orthopaedic Surgery, The Rothman Institute, Division of Hand Surgery, 925 Chestnut Street, Philadelphia, PA 19107. 0363-5023/12/37A10-0036$36.00/0 doi:10.1016/j.jhsa.2012.03.011
with maximum shrinkage of near 50% occurring above 65°C. By using these methods, capsular tissue can be shrunk without detrimental effects to its viscoelastic properties.8 In biomedical studies on rabbit joint capsule tissue treated with thermal energy, there was no difference in ultimate stress, yield stress, elastic modulus, or load-to-failure when it was compared with nontreated tissues.9 Collagen shrinkage is followed by fibroblastic nuclear pyknosis, which becomes apparent shortly following the thermal insult. In an experiment on sheep capsule, Hayashi et al demonstrated changes on the cellular level.10 Fibroblasts begin laying down collagen to repair the tissues, using the large denatured collagen fibrils as scaffolding. After the initial necrosis and hyalinization, tissue repair begins with fibroblast activation and capillary sprouting in the affected tissue. By 90 to 180 days, the area appears normal or as slightly hypercellular native tissue. ELECTROTHERMAL COLLAGEN SHRINKAGE IN SHOULDER AND KNEE SURGERY Arthroscopic procedures have improved surgical recovery and decreased postoperative discomfort compared to traditional open procedures. As the initial impetus for the implementation of electrothermal collagen shrinkage (ECS) in shoulder surgery, it was believed that arthroscopic thermal capsulorrhaphy could lead to a reduction in the need for open stabilization procedures. As such, it would be used as an adjunct to open or arthroscopic capsule–labral repairs.6 Gartsman and colleagues11 performed thermal capsulorrhaphy on patients with anterior–inferior glenohumeral instability to complement Bankart lesion repairs, with 92% good to excellent results. This initial enthusiasm waned after longer-term follow-up was evaluated. D’Alessandro and colleagues12 performed a nonrandomized prospective study evaluating the results of thermal capsulorrhaphy in 84 patients, with an average follow-up of 38 months. Using the American Shoulder and Elbow Surgeons shoulder assessment score, they found unsatisfactory outcomes in 31 patients (37%). In addition, complications including attenuation of capsular tissue, axillary nerve injury, and chondrolysis have been reported, further raising concern about ECS.13
© ASSH 䉬 Published by Elsevier, Inc. All rights reserved. 䉬 2165
In Brief
HISTORY The application of heat for coagulation and ablation of human tissues has traditionally posed an appealing method of treating a variety of pathologic conditions. In ophthalmology, the alteration of corneal curvature by means of thermal energy to correct various disorders affecting vision1 dates back to the 1960s. In cardiac surgery, electrochemical ablators have been used to disrupt abnormal conductive properties of cardiac tissues in patients with electrophysiological conductive alterations.2 After their introduction in cardiac surgery, electrothermal probes gained preference as a means to deliver heat to tissues because of their lower operating costs, safer use, ease of maneuverability, and accuracy.
2166
ELECTROTHERMAL COLLAGEN SHRINKAGE
Electrothermal collagen shrinkage in larger joints such as the knee was similarly met with initial interest followed by disappointment.14 When thermal shrinkage was performed on native and stretched graft anterior cruciate ligaments, results showed 79% failure rate for grafts and 38% failure rate for native ligaments.15 As a result, ECS as an adjunct to arthroscopic shoulder and knee surgery has been largely abandoned.
In Brief
ELECTROTHERMAL COLLAGEN SHRINKAGE IN HAND SURGERY In contrast, ECS has been used with some success in hand surgery, specifically as it relates to treatment of partial or “stretch” injuries of the scapholunate interosseous ligament. Hirsh and colleagues16 reported on 10 patients with structural disruption of the scapholunate interosseous ligament (Geissler type 2 injuries) treated with monopolar ECS of the scapholunate interosseous ligament. At minimum 12 months of followup, 9 patients (90%) were asymptomatic and had returned to their preinjury functional level. One patient developed recurrent symptoms 7 months after surgery and required revision surgery. In a similar study, Shih et al17 reported on 19 patients with static and dynamic scapholunate instability using monopolar ECS. They reported a 79% success rate at a minimum 24-month follow-up. Darlis et al18 reported on 16 patients with partial tears of the scapholunate interosseous ligament treated with ECS. Using the modified Mayo wrist score, they tabulated 14 excellent or good results, 1 fair result, and 1 poor result. No complications were described. In most of these studies, the postoperative course included immobilization in a splint for 6 to 8 weeks after surgery, followed by a course of physical therapy. Other uses in hand surgery have included debridement of triangular fibrocartilage complex tears, treatment of capsular laxity of the thumb carpometacarpal joint after hemitrapeziectomy,19 and treatment of midcarpal instability.20 The results in the literature evaluating the outcomes of ECS in hand surgery should be taken with great caution. This is true in light of the fact that the available data originate from a handful of studies with low levels of evidence, and especially given the experience of this modality in knee and shoulder surgery. Although it is possible that ECS might fall into disfavor, several important differences between the hand and wrist and the other anatomic areas might make this a successful modality in hand surgery. First, the hand and wrist can tolerate prolonged postoperative immobilization well, in contrast with the knee or shoulder. It is possible that the immobilization might allow the tissues to retain the increased stiffness following
the shrinkage and, therefore, decrease the rate of recurrence of laxity. Second, the smaller size of the structures and the lower levels of mechanical stresses might lead to a more favorable mechanical environment for tissues after ECS, although there is no evidence in the literature to support this assertion. Despite these theoretical advantages, it is clear that additional studies are needed to better understand the role, safety, and efficacy of this treatment modality in disorders of the hand and wrist. REFERENCES 1. Stringer H, Parr J. Shrinkage temperature of eye collagen. Nature 1964;204:1307. 2. An HL, Saksena S, Janssen M, Osypka P. Radiofrequency ablation of ventricular myocardium using active fixation and passive contact catheter delivery systems. Am Heart J 1989;118:69 –77. 3. Lopez MJ, Hayashi K, Fanton GS, Thabit G III, Markel MD. The effect of radiofrequency energy on the ultrastructure of joint capsular collagen. Arthroscopy 1998;14:495–501. 4. Van Haesendonck C, Sinnaeve A, Willems R, Vandenbulcke F, Stroobandt R. Biophysical and electrical aspects of radiofrequency catheter ablation. Acta Cardiol 1995;50:105–115. 5. Wallace AL, Hollinshead RM, Frank CB. The scientific basis of thermal capsular shrinkage. J Shoulder Elbow Surg 2000;9:354 –360. 6. Medvecky MJ, Ong BC, Rokito AS, Sherman OH. Thermal capsular shrinkage: Basic science and clinical applications. Arthroscopy 2001;17:624 – 635. 7. Naseef GS III, Foster TE, Trauner K, Solhpour S, Anderson RR, Zarins B. The thermal properties of bovine joint capsule. The basic science of laser- and radiofrequency-induced capsular shrinkage. Am J Sports Med 1997;25:670 – 674. 8. Hayashi K, Markel MD, Thabit G III, Bogdanske JJ, Thielke RJ. The effect of nonablative laser energy on joint capsular properties. An in vitro mechanical study using a rabbit model. Am J Sports Med 1995;23:482– 487. 9. Selecky MT, Vangsness CT Jr, Liao WL, Saadat V, Hedman TP. The effects of laser-induced collagen shortening on the biomechanical properties of the inferior glenohumeral ligament complex. Am J Sports Med 1999;27:168 –172. 10. Hayashi K, Nieckarz JA, Thabit GIII, Bogdanske JJ, Cooley AJ, Markel MD. Effect of nonablative laser energy on the joint capsule: an in vivo rabbit study using a holmium:YAG laser. Lasers Surg Med 1997;20:164 –171. 11. Gartsman GM, Roddey TS, Hammerman SM. Arthroscopic treatment of anterior-inferior glenohumeral instability. Two to five-year follow-up. J Bone Joint Surg 2000;82A:991–1003. 12. D’Alessandro DF, Bradley JP, Fleischli JE, Connor PM. Prospective evaluation of thermal capsulorrhaphy for shoulder instability: indications and results, two- to five-year follow-up. Am J Sports Med 2004;32:21–33. 13. Levine WN, Bigliani LU, Ahmad CS. Thermal capsulorrhaphy. Orthopedics 2004;27:823– 826. 14. Zheng N, Davis BR, Andrews JR. The effects of thermal capsulorrhaphy of medial parapatellar capsule on patellar lateral displacement. J Orthop Surg Res 2008;3:45. 15. Smith DB, Carter TR, Johnson DH. High failure rate for electrothermal shrinkage of the lax anterior cruciate ligament: a multicenter follow-up past 2 years. Arthroscopy 2008;24:637– 641. 16. Hirsh L, Sodha S, Bozentka D, Monaghan B, Steinberg D, Beredjiklian PK. Arthroscopic electrothermal collagen shrinkage for symptomatic laxity of the scapholunate interosseous ligament. J Hand Surg 2005;30B:643– 647.
JHS 䉬 Vol A, October
ELECTROTHERMAL COLLAGEN SHRINKAGE
carpometacarpal arthritis treated with arthroscopic hemitrapeziectomy and thermal capsular modification without interposition. J Hand Surg 2010;35A:566 –571. 20. Mason WT, Hargreaves DG. Arthroscopic thermal capsulorrhaphy for palmar midcarpal instability. J Hand Surg 2007;32E: 411– 416.
In Brief
17. Shih JT, Lee HM. Monopolar radiofrequency electrothermal shrinkage of the scapholunate ligament. Arthroscopy 2006;22:553–557. 18. Darlis NA, Weiser RW, Sotereanos DG. Partial scapholunate ligament injuries treated with arthroscopic debridement and thermal shrinkage. J Hand Surg 2005;30A:908 –914. 19. Edwards SG, Ramsey PN. Prospective outcomes of stage III thumb
2167
JHS 䉬 Vol A, October