Case Report
Intra-articular Migration of Femoral Interference Screw: Open or Arthroscopic Removal Sudheer L. Karlakki, F.R.C.S.(Orth), M.Sc.(Orth Eng), and Malcolm E. Downes, F.R.C.S.
Abstract: Migration of the femoral interference screw in to the knee joint following anterior cruciate reconstruction is a rare complication. A migrated interference screw usually requires removal as it often results in mechanical symptoms. Formal arthrotomy may be required to remove a dislodged screw lying in the femoral notch because arthroscopic removal can be difficult or not possible in the presence of an intact integrated anterior cruciate ligament graft or scarring in the notch. When attempting arthroscopic removal in a similar situation, one should foresee the possibility of a formal arthrotomy and this should be discussed with the patient and consent obtained preoperatively. Key Words: Knee joint—Anterior cruciate ligament—Femoral interference screw—Intra-articular migration.
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20-year-old man presented with a painful knee that had swelled immediately after a rugby tackle during training. Examination revealed a painful and locked knee with effusion. Arthroscopy was performed acutely in view of the persistent locking. There was grade 2 anterior cruciate laxity on evaluation under anesthesia. Arthroscopy revealed a midsubstance tear of the anterior cruciate ligament (ACL) and a minor peripheral lateral meniscal tear which was trimmed. The knee was treated with physiotherapy initially. Six weeks later, an ACL reconstruction was performed because of persistent and increasing symptoms of instability (Fig 1). ACL reconstruction was carried out using a middlethird bone–patellar tendon– bone graft and secured with interference screws through an open technique. The graft was secured using 2 cannulated screws, 7 ⫻
From the Department of Trauma and Orthopaedics, Swansea Hospital NHS Trust, Morriston, Swansea, United Kingdom. Address correspondence and reprint requests to Sudheer L. Karlakki, F.R.C.S.(Orth), M.Sc.(Orth Eng), Centre for Hip Surgery, Wrightington Hospital, Wrightington WN6 9EP, United Kingdom. E-mail:
[email protected] © 2003 by the Arthroscopy Association of North America 1526-3231/03/1903-3272$30.00/0 doi:10.1053/jars.2003.50070
20 mm, for the femoral tunnel and a 9 ⫻ 20 mm screw for the tibial tunnel. Bone quality was noted to be good and secure fixation was obtained. Postoperatively, the knee was treated with an accelerated rehabilitation regime without an external support. One year postoperatively, the patient was satisfied with the procedure, had returned to playing rugby, and had no symptoms of instability. A side-to-side difference of about 5 mm anterior cruciate laxity was noted on examination. The patient returned 8 months later (20 months postoperatively) after a minor injury with complaints of posteromedial knee pain, lack of full extension, and intermittent locking. On examination, there was a moderate effusion and grade I anterior cruciate laxity. The radiograph of the knee showed a dislodged femoral interference screw, lying in the posteromedial aspect of the femoral notch (Fig 2). The patient was listed for an arthroscopy with the aim of removing the screw arthroscopically, on the assumption that the graft would likely have failed, leaving access to the screw. On evaluation under anesthesia, there was 5 to 10 mm of anterior cruciate laxity compared with the other knee. Arthroscopy revealed a well-fixed graft except for minor anterior fraying. Attempts to remove the screw arthroscopically failed because the screw could not be seen or
Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 19, No 3 (March), 2003: p E19
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S. KARLAKKI AND M. E. DOWNES
FIGURE 1.
(A) Anteroposterior and (B) lateral radiographs of the knee in the immediate postoperative period.
reached due to the intact anterior cruciate graft and scarring in the femoral notch. A degenerative tear of the body and posterior horn of the medial meniscus was also found and was trimmed to the stable base. Because the patient had not given consent for the probable arthrotomy, the screw had to be removed at a later date in a second procedure through a posterior arthrotomy. On opening the knee joint, the screw was found to lie behind the cruciate ligaments and the scar tissue in the femoral notch. The screw was removed without further difficulty. The patient’s symptoms rapidly resolved after this procedure. DISCUSSION Lambert1 first described the use of interference screws for bone–patellar tendon– bone graft fixation in 1983. Since then, different types of screws have been tried with varying surface geometry and materials. Differing technical aspects on the length, diameter,
thread pattern of the screw, length of the bone plug, and the length of engagement of the screw over the graft are still being studied and reported.2-5 Evidence to date suggests that interference screw fixation is a good method of graft fixation, especially for the bone– patellar tendon– bone graft. The causes of loss of screw fixation have been well discussed2,5-7 and include smaller diameter screw, poor bone quality, screw divergence, and bone resorption. Migration of an interference screw with a wellfixed graft is rare and only 3 similar cases have been reported in the literature.6-8 In all of these cases, the migration of the screw was in the early postoperative period. Bone resorption during the remodeling phase was thought be the possible cause in 2 of these cases.6,7 In this particular case, we do not know the cause of the screw migration. We presume that it occurred late and displacement was precipitated during the second minor injury. However, we believe it to be highly likely that the majority of the screw had already mi-
MIGRATION OF FEMORAL INTERFERENCE SCREW
FIGURE 2.
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(A) Anteroposterior and (B) lateral radiographs after 2 years when the patient presented with pain and locking.
grated in the early remodeling phase with the second injury simply dislodging it completely. Another possibility is that the screw might not have been sufficiently advanced into the femoral tunnel initially but was sufficient to hold the graft in place and that the screw displacement occurred later. The second point we wish to highlight in this case report is that, even though the radiographic appearances suggested that the screw in the notch was easily accessible, the presence of a well-integrated graft and scarring in the notch made it difficult to visualize or access the screw for arthroscopic removal, even after debridement. Faced with a similar situation, one should foresee the possibility of formal arthrotomy and, hence, this should be discussed with the patient and appropriate consent obtained preoperatively. REFERENCES 1. Lambert KL. Vascularized patella graft with rigid internal fixation for anterior cruciate ligament instability. Clin Orthop 1983;172:85-89.
2. McGuire DA, Wolchok JC. Consistent and accurate graft passage and interference screw guide wire placement during single incision anterior cruciate ligament reconstruction. Arthroscopy 1997;13:526-529. 3. Schroeder FJ. Reduction of femoral interference screw divergence during endoscopic anterior cruciate ligament reconstruction. Arthroscopy 1999;15:41-48. 4. Pomeroy G, Baltz M, Pierz K, Nowak M, Post W, Fulkerson JP. The effects of bone plug length and screw diameter on the holding strength of bone-tendon-bone grafts. Arthroscopy 1998;14:148-152. 5. Mathews LS, Parks BG, Sabbagh RC. Determination of fixation strength of large diameter interference screws. Arthroscopy 1998;14:70-74. 6. Sidhu DS, Wroble RR. Intraarticular migration of a femoral interference fit screw—A complication of anterior cruciate ligament reconstruction. Am J Sports Med 1997;25:268271. 7. Joseph BR. Migration of femoral interference screw after anterior cruciate ligament reconstruction. Am J Knee Surg 1998;11:32-34. 8. Bottoni CR, DeBerardino TM, Fester EW, Mitchell D, Penrod BJ. An intra-articular bioabsorbable interference screw mimicking an acute meniscal tear 8 months after an anterior cruciate ligament reconstruction. Arthroscopy 2000;16:395398.
