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Transcutaneous migration of a tibial bioabsorbable interference screw after anterior cruciate ligament reconstruction
Case Report
Transcutaneous Migration of a Tibial Bioabsorbable Interference Screw After Anterior Cruciate Ligament Reconstruction Greg Sassmannshausen, M.D., and Charles F. Carr, M.D.
Abstract: We present a case of a poly-L-lactic acid (PLLA) tibial bioabsorbable interference screw disengaging and migrating transcutaneously 12 months after successful anterior cruciate ligament reconstruction with quadrupled hamstrings autograft. No graft insufficiency or joint inflammatory reaction was present. The screw was removed surgically with no evidence of resorption. The graft was well incorporated into the tibial tunnel. The patient recovered without difficulties and returned to her preinjury level of activity. To our knowledge, this is the first case reported of disengagement and extrusion of a PLLA bioabsorbable interference screw. Key Words: Anterior cruciate ligament reconstruction—Bioabsorbable—Interference screw—PLLA—Complication.
I
nterference screw fixation has proven to be an adequate adjunct for graft fixation in anterior cruciate ligament (ACL) reconstruction. Although biodegradable fixation has been used in trauma and in shoulder surgery for some time, bioabsorbable interference screws in ACL reconstruction were first used approximately 5 years ago. Reasons for their development included aiding in imaging postoperatively, allowing for ease of revision without the need for removing hardware, and avoiding graft injury encountered with aperture fixation using metallic screws. Multiple biomechanical and clinical studies have confirmed that the bioabsorbable interference screw provides adequate fixation for assorted grafts with results similar or superior to metal screws.1-6 As with any new technical device, caution is warranted while evaluating it for complications. Few complications from bioabsorbable interference screws have been reported.2,7,8
From the Department of Orthopaedics, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, U.S.A. Address correspondence and reprint requests to Charles F. Carr, M.D., 1 Medical Center Dr, Lebanon, NH 03756, U.S.A. E-mail: [email protected] © 2003 by the Arthroscopy Association of North America 0749-8063/03/1909-3545$30.00/0 doi:10.1016/S0749-8063(03)00832-6
We report the case of a tibial bioabsorbable interference screw disengaging from the tibial tunnel and undergoing subsequent transcutaneous migration.
CASE REPORT The patient is a 28-year-old woman who experienced a rotary-type injury to her right knee in January 2000 while skiing. After this acute event, she began to develop a sense of instability with persistent swelling. Subsequent evaluation noted a 2⫹ Lachman test, a KT-1000 showing 2.5-mm side-to-side difference, and a magnetic resonance imaging (MRI) scan showing a complete tear of the ACL. Because the patient had persistent symptoms despite a course of physical therapy and activity modifications, she underwent an endoscopic ACL reconstruction with a quadrupled autologous hamstring graft. Intraoperatively, no meniscal or chondral pathology was noted. The tibial tunnel was drilled to 6 mm and subsequently dilated to 7 mm in half-millimeter increments. Fixation on the femoral side was performed with 2 poly-L-lactic acid (PLLA) bioabsorbable cross pins. Tibial fixation included nonabsorbable sutures tied over a tibial screw along with an 8 ⫻ 28 mm PLLA
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 9 (November), 2003: E79
e133
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G. SASSMANNSHAUSEN AND C. F. CARR
bioabsorbable interference screw (Bio-Interference Screw; Arthrex, Naples, FL) placed anterior to the graft for aperture fixation. The surgery was performed without complications. Postoperatively, wounds healed without difficulties, and the patient was started on a standardized accelerated rehabilitation program, including return to full activities at 6 months. At the 9-month follow-up visit, the patient was doing well subjectively. Objective examination showed negative Lachman and anterior drawer tests. Twelve months after surgery, the patient began noticing erythema at the proximal extent of the anteromedial tibial incision. Over the next 4 weeks, a mass or fullness was felt in this area and subsequently wound dehiscence occurred. The patient noted the tip of the tibial bioabsorbable interference screw readily visible. She contacted us and underwent immediate examination. At no time did the patient complain of fever, chills, or other constitutional symptoms. She never had knee pain, swelling, or feelings of instability. Evaluation at this time showed the screw visible through the wound dehiscence with beefy granulation tissue at the wound edges. No pus or other signs of infection were seen. Examination of the knee showed full range of motion, a negative Lachman test, and no effusion. Radiographs showed minimal tibial tunnel widening without significant osteolysis (Figs 1 and 2). The patient was taken to the operating room for removal of the bioabsorbable interference screw and tibial post. Examination in the operating room again confirmed negative Lachman and pivot shift tests. The wound showed no sign of infection. The interference screw was completely disengaged from the tibial tunnel and rotated 180° with the leading edge of the screw pointing out of the wound (Fig 3). It was easily removed. No evidence of any resorption of the screw was seen. Inspection of the tibial tunnel showed excellent osseous integration of the hamstring autograft with scar tissue filling the screw defect. Tissue was sent for gram stain and culture. The wound was copiously irrigated and closed using absorbable suture. Postoperatively, no complications were noted, and the wound healed uneventfully. All final cultures were negative. The patient resumed her normal activities and has experienced no further episodes of instability or wound problems. DISCUSSION Bioabsorbable screws have become a well-accepted means for ACL graft fixation in reconstructive sur-
FIGURE 1. Anteroposterior radiograph of the knee 12 months after surgery shows tibial tunnel widening from the original 7-mm tunnel.
gery. Ultimately, they should provide adequate initial strength to allow for an accelerated rehabilitation while resorbing to allow full osseous integration of the graft. This will allow for unaltered imaging postoperatively with either MRI or computed tomography (CT). This also makes revision surgery easier without necessitating hardware removal. The rate of bioabsorption depends on the chemical make-up of the screw. The rate of breakdown for polyglycolic acid (PGA) is between 6 and 8 weeks. This rapid degradation has been associated with most symptomatic foreign-body reactions owing to the large amount of degradation by-products and subsequent local inflammatory response.9,10 PLLA resorbs in bone at a significantly slower rate, with the time to resorption unknown. Even when exposed to an intraarticular environment, the PLLA screw has been reported to be completely intact 2.5 years after insertion.11 However, the degradation of PLLA has been associated with a foreign body reaction almost 12
BIOABSORBABLE SCREW MIGRATION years after implantation.12 Because of the slow resorption and decreased likelihood of eliciting an inflammatory response, current bioabsorbable interference screws are composed of PLLA or a copolymer containing predominantly PLLA. Few adverse effects relating to the use of bioabsorbable interference screws have been reported. Concerns include intraoperative screw breakage, sterile drainage and effusions, and lack of complete osseous ingrowth into the defect created by the screw.13 Pretibial cyst formation has been reported after fixation using poly D,L-lactide-coglycolide (PDLLA) or polyglyconate bioabsorbable interference screws.2,8 These were believed to be secondary to relatively rapid breakdown of the polymer. In most cases, these resolved spontaneously; however, some required surgical treatment. In none of these cases has evidence of loose or disengaging screws been found. Bottoni et al.7 reported a case of a PLLA tibial bioabsorbable interference
e135
FIGURE 3. Intraoperative photograph shows extruded tibial bioabsorbable interference screw with beefy granulation tissue surrounding it. The screw is completely disengaged from the tibial tunnel, with the leading point migrated through the skin.
screw migrating intra-articularly 7 months after reconstruction. This was removed without difficulty. Stahelin et al.14 reported a case of a highly fragmented PDLLA tibial bioabsorbable interference screw spontaneously extruding from the tibial tunnel 3 weeks after implantation. This was attributed to the short degradation time of the screw. These are the only known reported cases of a bioabsorbable interference screw disengaging and migrating. Biodegradable interference screws continue to gain popularity and acceptance. Although complications have decreased with the use of newer PLLA polymers, care must be taken to be aware of potential complications. We present the only reported case of complete disengagement and extrusion of a nonresorbed PLLA tibial bioabsorbable interference screw with subsequent transcutaneous migration. REFERENCES
FIGURE 2. Lateral radiograph of the knee 12 months after surgery shows tibial tunnel widening from the original 7-mm tunnel.
1. Barber F, Elrod B, McGuire D, Paulos L. Preliminary results of an absorbable interference screw. Arthroscopy 1995;11: 573-588. 2. Benedetto KP, Fellinger M, Lim TE, et al. A new bioabsorbable interference screw: Preliminary results of a prospective, multicenter, randomized clinical trial. Arthroscopy 2000;16: 41-48. 3. Caborn DN, Coen M, Neef R, et al. Quadrupled semitendonosis-gracilis autograft fixation in the femoral tunnel: a comparison between a metal and a bioabsorbable interference screw. Arthroscopy 1998;14:241-245. 4. Kaousa P. Initial fixation strength of bioabsorbable and tita-
e136
5. 6. 7.
8. 9.
G. SASSMANNSHAUSEN AND C. F. CARR
nium interference screws in anterior cruciate ligament reconstruction: Biomechanical evaluation by single cycle and cyclic loading. Am J Sports Med 2001;29:420-425. McGuire DA, Barber FA, Elrod BF, Paulos LE. Bioabsorbable interference screws for graft fixation in anterior cruciate ligament reconstruction. Arthroscopy 1999;15:463-473. Weiler A, Hoffman R, Stahelin A, et al. Hamstring tendon fixation using interference screws: a biomechanical study in calf tibial bone. Arthroscopy 1998;14:29-37. Bottoni CR, DeBerardino TM, Fester EW, et al. An intraarticular bioabsorbable interference screw mimicking an acute meniscal tear 8 months after an anterior cruciate ligament reconstruction. Arthroscopy 2000;16:395-398. Martinek V, Friederich N. Tibial and pretibial cyst formation after anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation. Arthroscopy 1999;15:317-320. Bostman OM. Osteolytic changes accompanying degradation
10. 11. 12. 13. 14.
of absorbable fracture fixation implants. J Bone Joint Surg Br 1991;73:679-682. Burkhart A, Imhoff AB, Roscher E. Foreign-body reaction to the bioabsorbable Suretac device. Arthroscopy 2000;16:91-95. Martinek V, Seil R, Latterman C, et al. The fate of the poly-L-lactic acid interference screw after anterior cruciate ligament reconstruction. Arthroscopy 2001;17:73-76. Bostman OM, Pihlajamaki HK. Late foreign-body reaction to an intraosseous bioabsorbable polylactic acid screw. J Bone Joint Surg Am 1998;80:1791-1794. Ciccone WJ, Motz C, Bentley C, Tasto J. Bioabsorbable implants in orthopaedics: New developments and clinical applications. J Am Acad Orthop Surg 2001;9:280-288. Stahelin AC, Weiler A, Rufenacht H, et al. Clinical degradation and biocompatibility of different bioabsorbable interference screws: A report of 6 cases. Arthroscopy 1997;13:238244.
Transcutaneous Migration of a Tibial Bioabsorbable Interference Screw After Anterior Cruciate Ligament Reconstruction Greg Sassmannshausen, M.D., and Charles F. Carr, M.D.
Abstract: We present a case of a poly-L-lactic acid (PLLA) tibial bioabsorbable interference screw disengaging and migrating transcutaneously 12 months after successful anterior cruciate ligament reconstruction with quadrupled hamstrings autograft. No graft insufficiency or joint inflammatory reaction was present. The screw was removed surgically with no evidence of resorption. The graft was well incorporated into the tibial tunnel. The patient recovered without difficulties and returned to her preinjury level of activity. To our knowledge, this is the first case reported of disengagement and extrusion of a PLLA bioabsorbable interference screw. Key Words: Anterior cruciate ligament reconstruction—Bioabsorbable—Interference screw—PLLA—Complication.
I
nterference screw fixation has proven to be an adequate adjunct for graft fixation in anterior cruciate ligament (ACL) reconstruction. Although biodegradable fixation has been used in trauma and in shoulder surgery for some time, bioabsorbable interference screws in ACL reconstruction were first used approximately 5 years ago. Reasons for their development included aiding in imaging postoperatively, allowing for ease of revision without the need for removing hardware, and avoiding graft injury encountered with aperture fixation using metallic screws. Multiple biomechanical and clinical studies have confirmed that the bioabsorbable interference screw provides adequate fixation for assorted grafts with results similar or superior to metal screws.1-6 As with any new technical device, caution is warranted while evaluating it for complications. Few complications from bioabsorbable interference screws have been reported.2,7,8
From the Department of Orthopaedics, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire, U.S.A. Address correspondence and reprint requests to Charles F. Carr, M.D., 1 Medical Center Dr, Lebanon, NH 03756, U.S.A. E-mail: [email protected] © 2003 by the Arthroscopy Association of North America 0749-8063/03/1909-3545$30.00/0 doi:10.1016/S0749-8063(03)00832-6
We report the case of a tibial bioabsorbable interference screw disengaging from the tibial tunnel and undergoing subsequent transcutaneous migration.
CASE REPORT The patient is a 28-year-old woman who experienced a rotary-type injury to her right knee in January 2000 while skiing. After this acute event, she began to develop a sense of instability with persistent swelling. Subsequent evaluation noted a 2⫹ Lachman test, a KT-1000 showing 2.5-mm side-to-side difference, and a magnetic resonance imaging (MRI) scan showing a complete tear of the ACL. Because the patient had persistent symptoms despite a course of physical therapy and activity modifications, she underwent an endoscopic ACL reconstruction with a quadrupled autologous hamstring graft. Intraoperatively, no meniscal or chondral pathology was noted. The tibial tunnel was drilled to 6 mm and subsequently dilated to 7 mm in half-millimeter increments. Fixation on the femoral side was performed with 2 poly-L-lactic acid (PLLA) bioabsorbable cross pins. Tibial fixation included nonabsorbable sutures tied over a tibial screw along with an 8 ⫻ 28 mm PLLA
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 9 (November), 2003: E79
e133
e134
G. SASSMANNSHAUSEN AND C. F. CARR
bioabsorbable interference screw (Bio-Interference Screw; Arthrex, Naples, FL) placed anterior to the graft for aperture fixation. The surgery was performed without complications. Postoperatively, wounds healed without difficulties, and the patient was started on a standardized accelerated rehabilitation program, including return to full activities at 6 months. At the 9-month follow-up visit, the patient was doing well subjectively. Objective examination showed negative Lachman and anterior drawer tests. Twelve months after surgery, the patient began noticing erythema at the proximal extent of the anteromedial tibial incision. Over the next 4 weeks, a mass or fullness was felt in this area and subsequently wound dehiscence occurred. The patient noted the tip of the tibial bioabsorbable interference screw readily visible. She contacted us and underwent immediate examination. At no time did the patient complain of fever, chills, or other constitutional symptoms. She never had knee pain, swelling, or feelings of instability. Evaluation at this time showed the screw visible through the wound dehiscence with beefy granulation tissue at the wound edges. No pus or other signs of infection were seen. Examination of the knee showed full range of motion, a negative Lachman test, and no effusion. Radiographs showed minimal tibial tunnel widening without significant osteolysis (Figs 1 and 2). The patient was taken to the operating room for removal of the bioabsorbable interference screw and tibial post. Examination in the operating room again confirmed negative Lachman and pivot shift tests. The wound showed no sign of infection. The interference screw was completely disengaged from the tibial tunnel and rotated 180° with the leading edge of the screw pointing out of the wound (Fig 3). It was easily removed. No evidence of any resorption of the screw was seen. Inspection of the tibial tunnel showed excellent osseous integration of the hamstring autograft with scar tissue filling the screw defect. Tissue was sent for gram stain and culture. The wound was copiously irrigated and closed using absorbable suture. Postoperatively, no complications were noted, and the wound healed uneventfully. All final cultures were negative. The patient resumed her normal activities and has experienced no further episodes of instability or wound problems. DISCUSSION Bioabsorbable screws have become a well-accepted means for ACL graft fixation in reconstructive sur-
FIGURE 1. Anteroposterior radiograph of the knee 12 months after surgery shows tibial tunnel widening from the original 7-mm tunnel.
gery. Ultimately, they should provide adequate initial strength to allow for an accelerated rehabilitation while resorbing to allow full osseous integration of the graft. This will allow for unaltered imaging postoperatively with either MRI or computed tomography (CT). This also makes revision surgery easier without necessitating hardware removal. The rate of bioabsorption depends on the chemical make-up of the screw. The rate of breakdown for polyglycolic acid (PGA) is between 6 and 8 weeks. This rapid degradation has been associated with most symptomatic foreign-body reactions owing to the large amount of degradation by-products and subsequent local inflammatory response.9,10 PLLA resorbs in bone at a significantly slower rate, with the time to resorption unknown. Even when exposed to an intraarticular environment, the PLLA screw has been reported to be completely intact 2.5 years after insertion.11 However, the degradation of PLLA has been associated with a foreign body reaction almost 12
BIOABSORBABLE SCREW MIGRATION years after implantation.12 Because of the slow resorption and decreased likelihood of eliciting an inflammatory response, current bioabsorbable interference screws are composed of PLLA or a copolymer containing predominantly PLLA. Few adverse effects relating to the use of bioabsorbable interference screws have been reported. Concerns include intraoperative screw breakage, sterile drainage and effusions, and lack of complete osseous ingrowth into the defect created by the screw.13 Pretibial cyst formation has been reported after fixation using poly D,L-lactide-coglycolide (PDLLA) or polyglyconate bioabsorbable interference screws.2,8 These were believed to be secondary to relatively rapid breakdown of the polymer. In most cases, these resolved spontaneously; however, some required surgical treatment. In none of these cases has evidence of loose or disengaging screws been found. Bottoni et al.7 reported a case of a PLLA tibial bioabsorbable interference
e135
FIGURE 3. Intraoperative photograph shows extruded tibial bioabsorbable interference screw with beefy granulation tissue surrounding it. The screw is completely disengaged from the tibial tunnel, with the leading point migrated through the skin.
screw migrating intra-articularly 7 months after reconstruction. This was removed without difficulty. Stahelin et al.14 reported a case of a highly fragmented PDLLA tibial bioabsorbable interference screw spontaneously extruding from the tibial tunnel 3 weeks after implantation. This was attributed to the short degradation time of the screw. These are the only known reported cases of a bioabsorbable interference screw disengaging and migrating. Biodegradable interference screws continue to gain popularity and acceptance. Although complications have decreased with the use of newer PLLA polymers, care must be taken to be aware of potential complications. We present the only reported case of complete disengagement and extrusion of a nonresorbed PLLA tibial bioabsorbable interference screw with subsequent transcutaneous migration. REFERENCES
FIGURE 2. Lateral radiograph of the knee 12 months after surgery shows tibial tunnel widening from the original 7-mm tunnel.
1. Barber F, Elrod B, McGuire D, Paulos L. Preliminary results of an absorbable interference screw. Arthroscopy 1995;11: 573-588. 2. Benedetto KP, Fellinger M, Lim TE, et al. A new bioabsorbable interference screw: Preliminary results of a prospective, multicenter, randomized clinical trial. Arthroscopy 2000;16: 41-48. 3. Caborn DN, Coen M, Neef R, et al. Quadrupled semitendonosis-gracilis autograft fixation in the femoral tunnel: a comparison between a metal and a bioabsorbable interference screw. Arthroscopy 1998;14:241-245. 4. Kaousa P. Initial fixation strength of bioabsorbable and tita-
e136
5. 6. 7.
8. 9.
G. SASSMANNSHAUSEN AND C. F. CARR
nium interference screws in anterior cruciate ligament reconstruction: Biomechanical evaluation by single cycle and cyclic loading. Am J Sports Med 2001;29:420-425. McGuire DA, Barber FA, Elrod BF, Paulos LE. Bioabsorbable interference screws for graft fixation in anterior cruciate ligament reconstruction. Arthroscopy 1999;15:463-473. Weiler A, Hoffman R, Stahelin A, et al. Hamstring tendon fixation using interference screws: a biomechanical study in calf tibial bone. Arthroscopy 1998;14:29-37. Bottoni CR, DeBerardino TM, Fester EW, et al. An intraarticular bioabsorbable interference screw mimicking an acute meniscal tear 8 months after an anterior cruciate ligament reconstruction. Arthroscopy 2000;16:395-398. Martinek V, Friederich N. Tibial and pretibial cyst formation after anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation. Arthroscopy 1999;15:317-320. Bostman OM. Osteolytic changes accompanying degradation
10. 11. 12. 13. 14.
of absorbable fracture fixation implants. J Bone Joint Surg Br 1991;73:679-682. Burkhart A, Imhoff AB, Roscher E. Foreign-body reaction to the bioabsorbable Suretac device. Arthroscopy 2000;16:91-95. Martinek V, Seil R, Latterman C, et al. The fate of the poly-L-lactic acid interference screw after anterior cruciate ligament reconstruction. Arthroscopy 2001;17:73-76. Bostman OM, Pihlajamaki HK. Late foreign-body reaction to an intraosseous bioabsorbable polylactic acid screw. J Bone Joint Surg Am 1998;80:1791-1794. Ciccone WJ, Motz C, Bentley C, Tasto J. Bioabsorbable implants in orthopaedics: New developments and clinical applications. J Am Acad Orthop Surg 2001;9:280-288. Stahelin AC, Weiler A, Rufenacht H, et al. Clinical degradation and biocompatibility of different bioabsorbable interference screws: A report of 6 cases. Arthroscopy 1997;13:238244.