Lateral extra-articular tenodesis (LET) does not Increase lateral compartment contact pressures even in the face of subtotal meniscectomy

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1 Click to edit Master title style Lateral extra-articular tenodesis (LET) does not Increase lateral compartment contact pressures even in the face of subtotal meniscectomy Tomoyuki Shimakawa 1, Timothy A. Burkhart 1, Ryan M. Degen 1, Alan Getgood 1, 1 Fowler Kennedy Sports Medicine Clinic, Western University, London, ON, Canada

2 Click Disclosures to edit Master title style Tomoyuki Shimakawa Timothy Burkhart Ryan Degen Alan Getgood I have no financial conflicts to disclose. Support received from: Smith and Nephew I have no financial conflicts to disclose. Speaker: Conmed Paid Consultant: Smith and Nephew; Ossur; Collagen Solutions Support received from: Smith and Nephew; Ossur; Anthrax, Eupraxia

3 Introduction Click to edit Master title style Residual anterolateral laxity may persist following ACL reconstruction and may contribute to ACLR failure or early onset of osteoarthritis (OA) 1 An ACL reconstruction in combination with an LET has shown to be effective in reducing the pivot shift 2,3 However, there are concerns that the LET may cause overconstraint In addition, lateral meniscectomy may also increase the contact pressure, further increasing the risk of OA

4 Click Purpose to edit and Master Hypotheses title style Quantify changes in tibiofemoral joint contact pressures following isolated ACLR and combined ACLR/LET with varying states of lateral meniscal injury We hypothesized that: i) an LET in combination with an ACLR would not increase the lateral compartment pressures; and ii) a lateral meniscectomy following an LET would not increase the lateral compartment pressures

5 Click to edit Master title style Methods Femur Lateral femoral condyle Lateral meniscus Tibia Pressure Sensor Specimen Preparation Eight fresh-frozen cadaveric knees Mean (SD) age =60 (3.4 years) Mid-tibia to Mid-femur Tekscan pressure sensor arthroscopically inserted under the lateral meniscus

6 Click Methods to edit Master title style Experimental Conditions Baseline (ALL deficient ACL deficient) ACLR/LET/ Partial lateral meniscectomy ACLR (tibialis anterior allograft) ACLR/LET/ Subtotal lateral meniscectomy ACLR/LET (Modified Lemaire at 20N and 70 ) ACLR/total/LET release

7 Click to edit Master title style Methods Experimental Setup and Loading Protocol Specimens secured within an Instron materials testing system Pressure data collected when axially loaded at: 735N mean body weight force simulating single leg standing Loads applied at knee flexion angles between 0-90 at 30 increments Peak contact pressure, mean contact pressure and location of center of pressure measured for all conditions

8 Click Results to edit Master title style Mean and Peak Contact Pressure Significant difference in the mean contact pressure between baseline and ACLR/LET/Total and baseline and ACLR/Total/LET- at 0 (*p<0.05) Significant difference in the mean contact pressure between baseline and ACLR/LET at 30 (*p<0.05)

9 Results Click to edit Master title style Centre of Pressure Location The center of pressure was observed to be located significantly more anterior following partial meniscectomy (0,30 ), subtotal meniscectomy (0, 60 ), and when the LET was released (0,30,60 )

10 Click Discussion to edit and Master Conclusions title style Overall there was no increase in the lateral compartment pressure following an LET with and without various stages of meniscectomy This suggests that the LET does not over-constrain the lateral tibiofemoral compartment The LET was tensioned as per, Inderhaug et al., 4 who found that the lateral compartment contact pressure did not increase when fixation of LET at 20N These results are supported by long-term outcomes of LET that show no association between LET and lateral compartment OA at 20-years 5 Therefore, it may be safe to perform an LET in conjunction with ACLR with graft fixation at 70 flexion and 20N tension without significantly altering lateral compartment pressures

11 Click References to edit Master title style 1. Ferretti A. Extra-articular reconstruction in the anterior cruciate ligament deficient knee: a commentary. Joints 2014;2(1): Hewison CE, Tran MN, Kaniki N, Remtulla A, Bryant D, Getgood AM. Lateral Extraarticular Tenodesis Reduces Rotational Laxity When Combined With Anterior Cruciate Ligament Reconstruction: A Systematic Review of the Literature. Arthroscopy 2015;31(10): doi: /j.arthro Rezende FC, de Moraes VY, Martimbianco ALC, Luzo MV, da Silveira Franciozi CE, Belloti JC. Does Combined Intra- and Extraarticular ACL Reconstruction Improve Function and Stability? A Meta-analysis. Clin. Orthop. Relat. Res. 2015;473(8): doi: /s y. 4. Inderhaug E, Stephen JM, Williams A, Amis AA. Anterolateral Tenodesis or Anterolateral Ligament Complex Reconstruction: Effect of Flexion Angle at Graft Fixation When Combined With ACL Reconstruction. Am. J. Sports Med. 2017: doi: / Zaffagnini S, Marcheggiani Muccioli GM, Grassi A, et al. Over-the-top ACL Reconstruction Plus Extra-articular Lateral Tenodesis With Hamstring Tendon Grafts: Prospective Evaluation With 20-Year Minimum Follow-up. Am. J. Sports Med. 2017;45(14): doi: /