The Knee
Volume 18, Issue 1 , Pages 55-58, January 2011

Arthroscopic loose body removal and cyst decompression using a posterior trans-septal portal in the blind spot during knee arthroscopy—Technical report

  • Yong Seuk Lee

      Affiliations

    • Ajou University Medical Center, Republic of Korea
    • Corresponding Author InformationCorresponding author. Department of Orthopaedic Surgery, Ajou University Medical Center, San5, Wonchon-dong, Yeongtong-gu, Suwon, 443-721, Republic of Korea. Tel.: +82 31 219 5545, +82 10 2692 0765.
    • ,
  • Jin Hwan Ahn

      Affiliations

    • Samsung Medical Center, Sungkyunkwan University, Seoul, Republic of Korea
    • ,
  • Byoung-Hyun Min

      Affiliations

    • Ajou University Medical Center, Republic of Korea
    • ,
  • Kyung Wook Nha

      Affiliations

    • Inje University, Ilsanpaik Hospital, Republic of Korea

Received 3 November 2009; received in revised form 13 January 2010; accepted 16 January 2010. published online 17 February 2010.

Article Outline

Abstract 

Some lesions such as cyst, loose body, and mass around the knee joint tend to localize at the posterior aspect of the proximal tibia. Although arthroscopic procedures of the knee joint's posterior compartment have been developed through posteromedial, posterolateral, and posterior trans-septal portals, the posterior aspect of the proximal tibia remains difficult to access and manipulate. We report an arthroscopic loose body removal and cyst decompression on the posterolateral aspect of the proximal tibia using a posterior trans-septal portal. This area represents a blind spot in knee arthroscopy.

Keywords: Knee, Blind spot, Loose body, Cyst, Arthroscopy, Trans-septal portal

 

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1. Introduction 

Arthroscopy is considered to be the standard technique for loose body removal and cyst decompression in the knee joint [1], [2], [3], [4]. Despite remarkable advances in arthroscopic technology over the past decades through posteromedial, posterolateral, and posterior trans-septal portals, visualization of the posterior compartment remains difficult to see [4], [5].

In particular, the posterior aspect of the proximal tibia, a blind spot in knee arthroscopy, is difficult to access and manipulate. Accessory posterolateral portals and posteromedial portals were introduced to better access to see better [5]. We report an arthroscopic loose body removal and cyst decompression on the posteolateral aspect of the proximal tibia using a posterior trans-septal portal without an accessory portal.

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2. Technical report 

A 55-year-old woman presented to our clinic with a 1-year history of pain and discomfort in the medial side and popliteal area of the left knee joint. Physical examination revealed mild effusion, medial joint line tenderness, a positive McMurray test, and a 20° limitation of flexion compared to the right side. Plain radiographs of the left knee showed mild joint space narrowing. Magnetic resonance imaging (MRI) showed an articular cartilage defect at the medial femoral condyle and a popliteal cyst with loose bodies on the posterolateral aspect of the popliteus muscle–tendon junction. MRI showed that the cyst was connected to the posterior aspect of the posterior cruciate ligament (PCL) (Fig. 1). We felt that it was possible to decompress the lesion with a posterior trans-septal portal without an accessory posterolateral portal [5].

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  • Fig. 1 

    A 1.5-T MRI (Signa; General Electric Medical System, Milwaukee, Wisconsin) was used. Fat-suppression T2-weighted image (TR=3100, TE=54) (A) showing a cyst with loose bodies located on the posterior aspect of the popliteus muscle–tendon junction. Fat-suppression T2-weighted image [(B) coronal, (C) axial] showing a cyst connected to the PCL's posterior aspect.

An arthroscopic examination under general anesthesia was performed on the left knee. There was no ligamentous or meniscal injury, but there was a 1×3cm-sized osteochondral defect in the medial femoral condyle. We performed chondroplasty with a microfracture technique to treat the defect and then established posteromedial and posterolateral portals. Next, we tried to establish the posterior trans-septal portal as described in a previous report. The first step is to establish a posteromedial portal and the second step is to establish a posterolateral portal. The third step is to make an aperture at the posterior septum. An arthroscope is placed through the posteromedial portal, viewing the PCL and the posterior septum. The posterior septum is pushed medially by the switching stick which is placed through the posterolateral portal [6]. The posterior trans-septal portal was extended inferiorly to approach the cyst (Fig. 2). The procedure was performed at the just posterior aspect of the proximal tibia to prevent iatrogenic neurovascular injury. The cyst was automatically decompressed during the procedure and two loose bodies were found (Fig. 3). the loose bodies were removed through the posterolateral portal after viewing them from the posteromedial portal through the trans-septal portal. The patient's post-operative course was uneventful; 6months after surgery she had fully recovered the range of motion in her left knee and did not complain of any symptoms.

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  • Fig. 2 

    These schematic diagrams show extended posterior trans-septal portal. The loose body laden cyst is extended with the extension of posterior trans-septal portal. A: sagittal plane pre-extension, B: sagittal plane post-extension, C: coronal plane pre-extension, and D: coronal plane post-extension. PC: posterior capsule, PCL: posterior cruciate ligament, and P: popliteus.

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  • Fig. 3 

    As viewed from the posterolateral portal, a trans-septal portal was extended infero-laterally (A). Popliteus muscle was exposed and loose bodies were found (B). Digital pressure was applied to the posterolateral aspect of proximal tibia and loose bodies were moved to the proximal trans-septal portal area and these were extracted via posteromedial portal. MFC: medial femoral condyle, PC: posterior capsule, PCL: posterior cruciate ligament, and P: popliteus.

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3. Discussion 

The introduction of the posterior trans-septal portal greatly improved visualization of the posterosuperior aspect of the femoral condyles, the posterior portion of the PCL, the entire periphery of the posterior horn of the meniscus, the posterior meniscofemoral ligament, and the posterior aspect of the capsule [5]. This portal allows visual access through the posteromedial portal and instrument insertion through the posterior trans-septal portal, and vice versa [5]. This portal is useful in many arthroscopic surgeries [6].

Despite the advantages of a posterior trans-septal portal, some areas of the proximal tibia's posterior aspect remain visually inaccessible [5]. Oztekin reported a broken probe tip in the popliteal fossa; he believed that the broken probe migrated through a popliteal hiatus into the popliteal fossa during surgery [7]. Such occurrences compel knee surgeons to consider open surgery. It is possible to see down the popliteus tendon through the anterolateral portal and get an instrument down from a superolateral portal. However, it is difficult to access to the deep or medial portion of popliteal hiatus. Ahn et al. devised a new arthroscopic approach to the popliteal hiatus using two accessory portals [5]. Our case involved a cyst with loose bodies in the popliteal fossa, similar to the aforementioned report [5]. However, it was connected to the PCL's posterior aspect, which is usually decompressed during trans-septal portal formation. We thought that it would be possible to decompress the cyst using a trans-septal portal if it was extended inferiorly, because we usually extend the portal inferiorly in a trans-tibial PCL reconstruction using a trans-septal portal [8].

In summary, it is possible to perform arthroscopic surgery using a trans-septal portal in some cases, even when the lesion is located in the visually inaccessible popliteal fossa.

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4. Conflict of interest 

All authors certify that they not have signed any agreement with a commercial interest related to this study which would in any way limit publication of any and all data generated for the study or to delay publication for any reason.

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References 

  1. Ahn JH, Yoo JC, Lee SH. Arthroscopic loose-body removal in posterior compartment of the knee joint: a technical note. Knee Surg Sports Traumatol Arthrosc. 2007;15:100–106
  2. Dandy DJ, O'Carroll PF. The removal of loose bodies from the knee under arthroscopic control. J Bone Joint Surg Br. 1982;64:473–474
  3. McGinty JB. Arthroscopic removal of loose bodies. Orthop Clin North Am. 1982;13:313–328
  4. Morin WD, Steadman JR. Arthroscopic assessment of the posterior compartments of the knee via the intercondylar notch: the arthroscopist's field of view. Arthroscopy. 1993;9:284–290
  5. Ahn JH, Lee DH, Lee YS, Wang JH, Ha HC. Clearing a blind spot in knee arthroscopy: popliteal bursa. Knee Surg Sports Traumatol Arthrosc. 2008;16:549–552
  6. Ahn JH, Ha CW. Posterior trans-septal portal for arthroscopic surgery of the knee joint. Arthroscopy. 2000;16:774–779
  7. Oztekin HH. An unusual complication of knee arthroscopy: an extra-articular migrated asymptomatic broken probe from the knee joint. Arch Orthop Trauma Surg. 2005;125:285–287
  8. Lee YS, Ahn JH, Jung YB, Wang JH, Yoo JC, Jung HJ, et al. Transtibial double bundle posterior cruciate ligament reconstruction using TransFix tibial fixation. Knee Surg Sports Traumatol Arthrosc. 2007;15:973–977

PII: S0968-0160(10)00031-1

doi:10.1016/j.knee.2010.01.008

The Knee
Volume 18, Issue 1 , Pages 55-58, January 2011

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