Orthopaedics & Traumatology: Surgery & Research (2011) 97, 870—873 Available online at www.sciencedirect.com TECHNICAL NOTE High lateral portal for sparing the infrapatellar fat-pad during ACL reconstruction B. Sonnery-Cottet ∗, P. Archbold, R. Zayni, M. Thaunat, J. Bortolletto, J.-M. Fayard, P. Chambat Paul-Santy orthopaedic center, 24, avenue Paul-Santy, 69008 Lyon, France Accepted: 23 August 2011 KEYWORDS Summary During arthroscopic ACL reconstruction, intra-articular visualization can be com- Infrapatellar Fat Pad; promised by the interposition of the infrapatellar fat pad (IPFP) between the scope and the Anterior cruciate notch. In this technical note, we describe our technique of using lateral higher arthroscopic ligament portal, starting arthroscopy with the resection of the ligamentum mucosum and performing the reconstruction; tibial tunnel in 40◦ of knee flexion to optimise the intra-articular view without IPFP debride- Arthroscopy; ment. This technique was performed in 112 consecutive arthroscopic ACL reconstructions and Ligamentum compared to that in the previous 112 cases in which a conventional method was used. The use mucosum; of this technique was associated with a shorter operative time and no increase in the difficulty Arthroscopic portal in performing associated meniscal procedures. © 2011 Elsevier Masson SAS. All rights reserved. Introduction can influence patellar and knee kinematics [4]. Scarring of the anterior interval changes the mechanics of the anterior During arthroscopic ACL reconstruction, intra-articular visu- structures of the knee and may lead to refractory anterior alization can be compromised by the interposition of the knee pain [1]. Some studies have shown that the excessive infrapatellar fat pad (IPFP) between the scope and the resection of IPFP can have negative consequences on the notch. In order to allow an adequate view of the notch shav- operated knee [2,4,5]. Therefore, it is important to avoid ing of the IFPP is often required. However, many recent an excessive resection of this tissue. articles highlight the biochemical function of the IPFP [1] In this paper, we describe a technique that uses higher arthroscopic portals [6], resects the ligamentum mucusom in particular its role as a modulator of the inflammation of ◦ the injured knee [2]. In addition, the fat pad participates and performs the tibial tunnel in 40 of knee flexion to opti- in the neo-vascularization of the ACL graft [3]. Biomechan- mise the intra-articular view without IPFP debridement. ically, Bohnsack et al. has found that the resection of IPFP Anatomy of infrapatellar fat pad ∗ Corresponding author. Tel.: +33 (0) 43 75 30 022. The IPFP occupies the anterior compartment of the knee E-mail address: [email protected] (B. Sonnery-Cottet). and is intra-articular but extra-synovial [7]. Its shape and 1877-0568/$ – see front matter © 2011 Elsevier Masson SAS. All rights reserved. doi:10.1016/j.otsr.2011.08.007 High lateral portal for sparing the infrapatellar fat-pad during ACL reconstruction 871 size is variable [8] and its blood supply is ensured by two adjacent arteries communicating through two to three hori- zontal branches [9]. From its posterior surface, in its middle portion, begins a fold of synovium called the infrapatellar plica or ligamentum mucosum. This extends to the apex of the intercondylar notch [10]. The ligamentum mucosum may appear as a single fibrous band or as a true septum that divides the knee in two distinct compartments medial and lateral [10]. According to Abreu et al. [11] and Broker et al. [12], this plica is found in 50 to 79% of the knees and may or may not be connected to the synovial membrane of the anterior cruciate ligament (Video 1). Abreu et al. [11] in a retro- spective MRI study on patients showed that abnormalities of IPFP, such as focal and diffuse edema, tears, scars and synovial proliferation, are more common in knees with torn ACLs than in knees with intact ACLs. This demonstrates its close relationship with the ACL. Surgical procedure Figure 1 Classic portals and high portals. The surgical technique for ACL reconstruction has been previously described [13]. The correct placement of the arthroscopic portals is crucial for a successful and uncompli- cated procedure. We now perform the anterolateral portals The IPFP may also impede adequate visualization when as described by Kim et al. [6]. The lateral portal is per- positioning the tibial guide. When placing the tibial guide- formed at the highest position possible just off the lateral aiming hook on the ACL footprint, the arthroscope can enter edge of the patellar tendon and just off the inferior bor- the IPFP and vision can be reduced. We solve this problem ◦ der of the patella (Fig. 1). This position allows the surgeon by holding the knee in 40 of flexion (Video 2). This helps to to avoid the IPFP and ensures an excellent wide view of the move the IPFP anteriorly with the patellar tendon, taking it intra-articular structures, especially the intercondylar notch away from the arthroscopic view. (Fig. 2). The anteromedial portal is performed just below This technique was performed in 112 consecutive arthro- the inferior border of the patella and about 4 mm medially scopic ACL reconstructions and compared to that in the to the medial border of the patellar tendon. Once inside previous 112 cases in which a conventional method was used. the articulation, the first structure we find and resect is the The ligamentum mucosum was present in 78% of knees. ligamentum mucosum. This is performed with a 90◦ flexed We encountered no particular problems in performing these knee orienting the scope toward the anterior aspect of the procedures using the higher portals. The mean operating notch. When the ligamentum mucosum is released, the IPFP time using the classical portals were 38,3 mins (min 22, is pushed anteriorly by the pressure of the intrarticular liquid max 63) and 33,2 mins (min 20, max 48) using the modified (Video 1). technique to preserve the IPFP. Figure 2 Cadaveric dissection of a left knee. A Classic anteromedial portal: the scope passes through the IPFP,making its resection necessary to adequately visualise the notch. B. A higher portal avoids the IPFP and makes the resection of the ligamentum mucosum easier. MFC: Medial femoral condyle. IPFP: Infra patellar fat pad. LM: Ligamentum mucosum. 872 B. Sonnery-Cottet et al. Discussion In conclusion, during ACL reconstruction evidence sug- gests that it is important to preserve the IPFP. In our The classical anterolateral portal has been described as practice, this can be achieved by the use of higher arthro- being located approximately 1 cm lateral to the patellar ten- scopic portals, by resecting the ligamentum mucosum at the don and 1 cm superior to the lateral joint line. Alternatively, start of the procedure and by performing the tibial tunnel in ◦ it can be just lateral to the patellar tendon and approxi- 40 of knee flexion. This results in a shorter operative time mately 2 mm above the anterior horn of the lateral meniscus with no additional increase in the difficulty of performing identified by palpating the depression above Gerdy’s tuber- additional meniscal procedures. cle and incising just above it [14]. The inferior pole of the patella is commonly used as a vertical landmark for this por- Disclosure of interest tal. As advocated by Kim [6], we believe that the best way to avoid the fat pad is to perform a high anterolateral portal (Fig. 2). Moreover, higher portal placement allows a wider The authors declare that they have no conflicts of interest field of view, facilitates visualization of the medial gutter concerning this article. and the anterior horn of the lateral meniscus, which can be hard to see through a lower anterolateral portal. The Appendix A. Supplementary data use of a high anteromedial portal decreases the risk of IPFP penetration and facilitates the resection of the ligamen- tum mucosum. As we routinely use an outside in femoral Supplementary data associated with this article can guide, femoral tunnel positioning is not compromised with be found, in the online version, at http://www. this high portal but this could be challenging using an inside sciencedirect.com and doi:10.1016/j.otsr.2011.08.007. out technique. Surgeons can be reluctant to perform high portals in References case of a simultaneous meniscal and ACL tear, as por- tal placement is critical while performing meniscectomy [1] Jurgens WJ, van Dijk A, Doulabi BZ, et al. Freshly isolated or meniscal repairs. However, if a lateral tear is encoun- stromal cells from the infrapatellar fat pad are suitable for tered, high portals do not limit the access to the meniscus a one-step surgical procedure to regenerate cartilage tissue. because the anteromedial portal needs to be high to allow Cytotherapy 2009;11:1052—64. instruments to pass freely above the tibial spines. Fur- [2] Clockaerts S, Bastiaansen-Jenniskens YM, Runhaar J, et al. thermore, when the knee is positioned in the four-figure The infrapatellar fat pad should be considered as an active position high portals afford an excellent view and easy osteoarthritic joint tissue: a narrative review. Osteoarthritis access within the joint. The main concern with high por- Cartilage 2010;18:876—82. tals is how to perform a posteromedial meniscectomy or [3] Arnoczky SP, Tarvin GB, Marshall JL. Anterior cruciate lig- a posteromedial meniscal repair without damaging the ament replacement using patellar tendon. An evaluation of graft revascularizatioin the dog. J Bone Joint Surg Am articular surface of the medial condyle. A high portal 1982;64:217—24. allows this type of procedure to be performed without [4] Bohnsack M, Wilharm A, Hurschler C, Ruhmann O, Stukenborg- increased difficulty, especially when using the specific Colsman C, Wirth CJ.