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Case Report

Extra-articular and transcutaneous migration of the poly- l/d-lactide interference screw after popliteal tendon reconstruction

Migração extra-articular e transcutânea de parafuso de interferência de poly L,D-lactide após reconstrução do tendão poplíteo

Camilo Partezani Helito*, Noel O. Foni, Marcelo Batista Bonadio, José Ricardo Pécora, Marco Kawamura Demange, Fabio Janson Angelini


    Knee ligament reconstructions are commonly performed orthopedic procedures. Graft fixation is generally performed with metallic or absorbable interference screws. In a recent study, only ten reports of screw migration were retrieved; of these, only one was not related to the anterior cruciate ligament, and the majority was related to the use ofpoly-l-lactic acid (PLLA) screws. Only one case retrieved in the literature reported screw migration in reconstructions of the posterolateral corner, and that was to the intra-articular region. In the present article, the authors report a case of extra-articular and transcutaneous migration of a poly-l/dlactide (PDLLA) interference screw following popliteal tendon reconstruction. Besides being the first case of popliteal tendon migration with extra-articular screw migration, no reports of PDLLA screw migration were retrieved in the literature.


    As reconstruc¸ões ligamentares do joelho são procedimentos ortopédicos frequentes. As fixac¸ões dos enxertos são mais comumente feitas com parafusos de interferência, metá- licos ou absorvíveis. Em estudo recente, somente dez relatos sobre migrac¸ão de parafusos foram encontrados; somente um deles não estava relacionado ao ligamento cruzado anterior (LCA) e a maioria estava relacionada a parafusos de poly-L-lactic acid (PLLA). Apenas um caso da literatura reportou migrac¸ão de parafuso em reconstruc¸ões do canto posterolateral, essa para a região intra-articular. Neste artigo, os autores relatam um caso de migrac¸ão extra-articular e transcutânea de um parafuso de interferência de poly L,D-lactide (PDLLA) após a reconstruc¸ão do tendão poplíteo. Além de ser o primeiro caso de reconstruc¸ão do tendão do poplíteo com migrac¸ão extra-articular do parafuso, não foram encontrados na literatura relatos de migrac¸ão de parafusos de PDLLA.  

Universidade de São Paulo (USP), Hospital das Clínicas, Instituto de Ortopedia e Traumatologia, São Paulo, SP, Brazil



Ligament reconstructions of the knee are fairly frequent orthopedic procedures. Among all reconstructions, surgery of the anterior cruciate ligament (ACL) is the most common,1 but 16% of these lesions also involve the posterolateral ligament complex.2

Bone fixations of the grafts used can be made with numerous devices, but the most commonly used are interference screws, which may be metallic or absorbable. Recent comparative studies have found no functional differences between patients in whom metallic or absorbable screws were used.3,4 As disadvantages, metallic screws present the risk of damaging the graft, especially in the case of soft tissue grafts, and making the reconstruction more fragile, as well as turning into artifacts on magnetic resonance imaging and often requiring removal in revision ligament reconstruction surgeries.3,5–7 In turn, absorbable screws have as disadvantages the possibility of breakage and migration, as well as inflammatory synovitis. In a recent study by Pereira et al.,8 the authors found only ten case reports on migration of absorbable screws, and only one of them was not related to the ACL. Most common migration was to the intra-articular region; only two cases migrated to the extra-articular region, one in the femur and one in the tibia. Only one case in the literature reported the migration of part of a screw in reconstructions of the posterolateral corner (PC); this migration was into the intra-articular region.

The authors report a case of extra-articular and transcutaneous migration of an absorbable interference screw after reconstruction of the popliteus tendon in a condition of posterolateral ligament insufficiency. Case report

In June 2011, a 33-year-old male patient was involved in a car accident that caused dislocation of his right knee. He was initially treated in a regional emergency service, in which a closed reduction of the dislocation and immobilization with an extension brace was performed. Patient did not present neurovascular lesions or other associated orthopedic lesions. He was then transferred to a referral service for definitive treatment of the lesions. The posterior and anterior drawer test were positive, as well as posterolateral tibial rotation and varus stress; therefore, posterior cruciate ligament (PCL), PC, and ACL lesions were diagnosed.9,10

In August 2011, two months after the initial injury and after a gain in range of motion (ROM), patient underwent inlay PCL reconstruction with Achilles tendon from tissue bank with bone plug, and PC reconstruction with two posterior tibial grafts from a tissue bank. The lateral collateral ligament, popliteus tendon, and popliteal fibular ligament were reconstructed. No ACL reconstruction was performed. After the reconstructions, an articulated external fixator was installed for early ROM gain and protection of grafts. Fixations were made with absorbable interference screws made of poly-d,llactide (PDLLA) except for the tibial inlay PCL fixation. Fixation was removed six weeks after surgery.11–14 From a functional standpoint, patient is progressing well, with a return to pre-injury activities after eight months of rehabilitation. He did not present complaints until 15 months postoperatively, when he noticed a bulging appearance in the anterolateral region of the leg. Initially, he did not seek medical attention, but after four weeks of symptoms he noticed the protrusion of part of one of the screws and came to the hospital (Fig. 1).

Patient was taken to the operating room, whereupon screw was completely removed, associated with surgical cleaning and closure of the puncture. The screw was intact, with no signs of degradation at the time of its removal (Fig. 2). Cultures collected intraoperatively indicated the presence of Staphylococcus aureus. Patient was treated with oxacillin and rifampicin according to the protocol of the infection committee of this institution, with success. At the time of surgery he was examined under anesthesia, demonstrating no posterior or posterolateral instability. In his last follow-up evaluation, four years after the reconstruction surgery, he presented complete clinical improvement, without complaints, with normal range of motion and no instability (Figs. 3 and 4).

Discussion The case presented is unique since it shows extra-articular and transcutaneous migration of an absorbable interference screw after PCL reconstruction, more specifically the tunnel used for reconstruction of the popliteus tendon.

Migration of extra-articular and transcutaneous implants of the knee are not uncommon; there are reports of migration ranging from prosthetic components to interference screws.8,15,16 Screw migrations are more common after ACL reconstruction, albeit still low in number.

Among the reports retrieved in the literature, the most common material to present migration is poly-l-lactic acid (PLLA). This polymer is most often used in orthopedic materials and presented good results in published studies,17,18 but adverse effects of its degradation can be observed up to three years after surgery. The development of PDLLA screws aimed

to improve implants by lowering PLLA reactions, but complications from their use, such as formation of pre-tibial cysts, have been reported.19 Nonetheless, to the best of the authors’ knowledge, there are no cases of screw migration with the use of this material to date.

The bioabsorbable material passes through the following steps after its implantation: hydration, depolymerization, mass loss, absorption, and elimination. During degradation, hydrolysis may occur and particles may be phagocytosed by Fig. 2 – Intact poly- d, l-lactide interference screw removed after transcutaneous migration. macrophages. Such process may be associated with formation of cysts.19–21 The authors postulate that screw migration can also be related to some complications in the process. Due to the small number ofreports in the literature, it is not possible to establish a causal relationship regarding the reason for this complication. It was hypothesized that there is a relationship between tunnel and screw size with its migration, which was discarded in previous articles.8

It is always important to considerthe differential diagnoses of screw migration, such as meniscal injury, periarticular fracture, and ACL rupture.22 Typically, this diagnosis is not easily made, since a small migration can be mistaken with other pathologies. This difficulty occurs only in cases of intra-articular migration of the implant. As the screw migration in the present patient was extra-articular and transcutaneous, visible outside the patient’s knee, the diagnosis was made with no intercurrences. Imaging studies may be important to differentiate this migration from the formation of pre-tibial cysts in cases of diagnostic doubt.18,19

As the migration occurred 15 months postoperatively, patient did not present any problems regarding knee instability, despite the reconstructions having been made with tissue grafts, which have slower bone integration than autologous grafts.23

The authors reported a case of a patient undergoing posterolateral reconstruction who evolved with extra-articular and transcutaneous migration of the bioabsorbable screw. There are no similar studies in the literature with the type of polymer used in the reconstruction.

Conflicts of interest
The authors declare no conflicts of interest.



1. Chambat P, Guier C, Sonnery-Cottet B, Fayard JM, Thaunat M. The evolution of ACL reconstruction over the last fifty years. Int Orthop. 2013;37(2):181–6. 2. Crespo B, James EW, Metsavaht L, LaPrade RF. Injuries to posterolateral corner of the knee: a comprehensive review from anatomy to surgical treatment. Rev Bras Ortop. 2014;50(4):363–70. 3. Emond CE, Woelber EB, Kurd SK, Ciccotti MG, Cohen SB. A comparison of the results of anterior cruciate ligament reconstruction using bioabsorbable versus metal interference screws: a meta-analysis. J Bone Joint Surg Am. 2011;93(6):572–80. 4. Shen C, Jiang SD, Jiang LS, Dai LY. Bioabsorbable versus metallic interference screw fixation in anterior cruciate ligament reconstruction: a meta-analysis of randomized controlled trials. Arthroscopy. 2010;26(5):705–13. 5. Halewood C, Hirschmann MT, Newman S, Hleihil J, Chaimski G, Amis AA. The fixation strength of a novel ACL soft-tissue graft fixation device compared with conventional interference screws: a biomechanical study in vitro. Knee Surg Sports Traumatol Arthrosc. 2011;19(4):559–67. 6. Drogset JO, Straume LG, Bjørkmo I, Myhr G. A prospective randomized study of ACL-reconstructions using bone-patellar tendon-bone grafts fixed with bioabsorbable or metal interference screws. Knee Surg Sports Traumatol Arthrosc. 2011;19(5):753–9. 7. Moisala AS, Järvelä T, Paakkala A, Paakkala T, Kannus P, Järvinen M. Comparison ofthe bioabsorbable and metal screw fixation after ACL reconstruction with a hamstring autograft in MRI and clinical outcome: a prospective randomized study. Knee Surg Sports Traumatol Arthrosc. 2008;16(12):1080–6. 8. Pereira H, Correlo VM, Silva-Correia J, Oliveira JM, Reis RL, Espregueira-Mendes J. Migration of bioabsorbable screws in ACL repair. How much do we know? A systematic review. Knee Surg Sports Traumatol Arthrosc. 2013;21(4):986–94. 9. Rihn JA, Groff YJ, Harner CD, Cha PS. The acutely dislocated knee: evaluation and management. J Am Acad Orthop Surg. 2004;12(5):334–46. 10. Angelini FJ, Bonadio MB, Helito CP, da Mota E, Albuquerque RF, Pécora JR, et al. Description of the posterolateral rotatory drawer maneuver for the identification of posterolateral corner injury. Arthrosc Tech. 2014;3(2):e299–302. 11. Angelini FJ, Helito CP, Bonadio MB, Guimarães TM, Barreto RB, Pécora JR, et al. External fixator for treatment of the sub-acute and chronic multi-ligament-injured knee. Knee Surg Sports Traumatol Arthrosc. 2015;23(10):3012–8. 12. Marcacci M, Zaffagnini S, Bonanzinga T, Pizzoli A, Manca M, Caiaffa E. Surgical technique: articulated external fixator for treatment of complex knee dislocation. Clin Orthop Relat Res. 2012;470(3):869–76. 13. Stannard JP, Nuelle CW, McGwin G, Volgas DA. Hinged external fixation in the treatment of knee dislocations: a prospective randomized study. J Bone Joint Surg Am. 2014;96(3):184–91. 14. Angelini FJ, Helito CP, Bonadio MB, Albuquerque RFM, Pecora JR, Camanho GL. Surgical management of knee dislocations with ligament reconstruction associated with a hinged external fixator. Orthop Traumatol Surg Res. 2015;101(1):77–81.15. Helito CP, Gobbi RG, Tirico LE, Pecora JR, Camanho GL. Loosening of the patellar component and extra-articular and transcutaneous migration after TKA. Orthopedics. 2014;37(2):e211–3. 16. Chatterji U, Almedghio S. Complete dislodgement of a femoral component of a knee arthroplasty and expulsion through an infected sinus. J Arthroplasty. 2012;27(3), 494.e17–8. 17. Maletis GB, Cameron SL, Tengan JJ, Burchette RJ. A prospective randomized study of anterior cruciate ligament reconstruction: a comparison of patellar tendon and quadruple-strand semitendinosus/gracilis tendons fixed with bioabsorbable interference screws. Am J Sports Med. 2007;35(3):384–94. 18. Drogset JO, Grøntvedt T, Myhr G. Magnetic resonance imaging analysis of bioabsorbable interference screws used for fixation of bone-patellar tendon-bone autografts in endoscopic reconstruction of the anterior cruciate ligament. Am J Sports Med. 2006;34(7):1164–9. 19. Martinek V, Friederich NF. Tibial and pretibial cyst formation after anterior cruciate ligament reconstruction with bioabsorbable interference screw fixation. Arthroscopy. 1999;15(3):317–20. 20. Malhan K, Kumar A, Rees D. Tibial cyst formation after anterior cruciate ligament reconstruction using a new bioabsorbable screw. Knee. 2002;9(1):73–5. 21. Gonzalez-Lomas G, Cassilly RT, Remotti F, Levine WN. Is the etiology of pretibial cyst formation after absorbable interference screw use related to a foreign body reaction? Clin Orthop Relat Res. 2011;469(4):1082–8. 22. Sharma V, Curtis C, Micheli L. Extra-articular extraosseous migration of a bioabsorbable femoral interference screw after ACL reconstruction. Orthopedics. 2008;31(10), pii: 23. Cerulli G, Placella G, Sebastiani E, Tei MM, Speziali A, Manfreda F. ACL reconstruction choosing the graft. Joints. 2013;1(1):18–24.